Oncogenically active MYD88 mutations in human lymphoma.

PubMed

Ngo, Vu N; Young, Ryan M; Schmitz, Roland; Jhavar, Sameer; Xiao, Wenming; Lim, Kian-Huat; Kohlhammer, Holger; Xu, Weihong; Yang, Yandan; Zhao, Hong; Shaffer, Arthur L; Romesser, Paul; Wright, George; Powell, John; Rosenwald, Andreas; Muller-Hermelink, Hans Konrad; Ott, German; Gascoyne, Randy D; Connors, Joseph M; Rimsza, Lisa M; Campo, Elias; Jaffe, Elaine S; Delabie, Jan; Smeland, Erlend B; Fisher, Richard I; Braziel, Rita M; Tubbs, Raymond R; Cook, J R; Weisenburger, Denny D; Chan, Wing C; Staudt, Louis M

2011-02-03

The activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) remains the least curable form of this malignancy despite recent advances in therapy. Constitutive nuclear factor (NF)-κB and JAK kinase signalling promotes malignant cell survival in these lymphomas, but the genetic basis for this signalling is incompletely understood. Here we describe the dependence of ABC DLBCLs on MYD88, an adaptor protein that mediates toll and interleukin (IL)-1 receptor signalling, and the discovery of highly recurrent oncogenic mutations affecting MYD88 in ABC DLBCL tumours. RNA interference screening revealed that MYD88 and the associated kinases IRAK1 and IRAK4 are essential for ABC DLBCL survival. High-throughput RNA resequencing uncovered MYD88 mutations in ABC DLBCL lines. Notably, 29% of ABC DLBCL tumours harboured the same amino acid substitution, L265P, in the MYD88 Toll/IL-1 receptor (TIR) domain at an evolutionarily invariant residue in its hydrophobic core. This mutation was rare or absent in other DLBCL subtypes and Burkitt's lymphoma, but was observed in 9% of mucosa-associated lymphoid tissue lymphomas. At a lower frequency, additional mutations were observed in the MYD88 TIR domain, occurring in both the ABC and germinal centre B-cell-like (GCB) DLBCL subtypes. Survival of ABC DLBCL cells bearing the L265P mutation was sustained by the mutant but not the wild-type MYD88 isoform, demonstrating that L265P is a gain-of-function driver mutation. The L265P mutant promoted cell survival by spontaneously assembling a protein complex containing IRAK1 and IRAK4, leading to IRAK4 kinase activity, IRAK1 phosphorylation, NF-κB signalling, JAK kinase activation of STAT3, and secretion of IL-6, IL-10 and interferon-β. Hence, the MYD88 signalling pathway is integral to the pathogenesis of ABC DLBCL, supporting the development of inhibitors of IRAK4 kinase and other components of this pathway for the treatment of tumours bearing oncogenic MYD88 mutations.

Effect of β-elemene on the kinetics of intracellular transport of d-luciferin potassium salt (ABC substrate) in doxorubicin-resistant breast cancer cells and the associated molecular mechanism.

PubMed

Tang, Chao-Yuan; Zhu, Li-Xin; Yu, Jian-Dong; Chen, Zhi; Gu, Man-Cang; Mu, Chao-Feng; Liu, Qi; Xiong, Yang

2018-07-30

In order to explore the mechanism of the reversing multidrug resistance (MDR) phenotypes by β-elemene (β-ELE) in doxorubicin (DOX)-resistant breast cancer cells (MCF-7/DOX), both the functionality and quantity of the ABC transporters in MCF-7/DOX were studied. Bioluminescence imaging (BLI) was used to study the efflux of d-luciferin potassium salt, the substrate of ATP-binding cassette transporters (ABC transporters), in MCF-7/DOX cells treated by β-ELE. At the same time three major ABC transport proteins and genes-related MDR, P-glycoprotein (P-gp, ABCB1) and multidrug resistance-associated protein 1 (MRP, ABCC1) as well as breast cancer resistance protein (BCRP, ABCG2) were analyzed by q-PCR and Western blot. To investigate the efflux functionality of ABC transporters, MCF-7/DOX Fluc cell line with stably-overexpressed luciferase was established. BLI was then used to real-time monitor the efflux kinetics of d-luciferin potassium salt before and after MCF-7/DOX Fluc cells being treated with β-ELE or not. The results showed that the efflux of d-luciferin potassium salt from MCF-7/DOX Fluc was lessened when pretreated with β-ELE, which means that β-ELE may dampen the functionality of ABC transporters, thus decrease the efflux of d-fluorescein potassium or other chemotherapies which also serve as the substrates of ABC transporters. As the effect of β-ELE on the expression of ABC transporters, the results of q-PCR and Western blot showed that gene and protein expression of ABC transporters such as P-gp, MRP, and BCRP were down-regulated after the treatment of β-ELE. To verify the efficacy of β-ELE on reversing MDR, MCF-7/DOX cells were treated with the combination of DOX and β-ELE. MTT assay showed that β-ELE increased the inhibitory effect of DOX on the proliferation of MCF-7/DOX, and the IC 50 of the combination group was much lower than that of the single DOX or β-ELE treatment. In all, β-ELE may reverse MDR through the substrates of ABC transporters by two ways, to lessen the ABC protein efflux by weakening their functionality, or to reduce the quantity of ABC gene and protein expression. Copyright © 2018. Published by Elsevier B.V.

75 FR 11991 - ABC & D Recycling, Inc.-Lease and Operation Exemption-a Line of Railroad in Ware, MA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-12

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [STB Finance Docket No. 35356] ABC & D Recycling, Inc.--Lease and Operation Exemption--a Line of Railroad in Ware, MA ABC & D Recycling, Inc. (ABC & D), a noncarrier, has filed a verified notice of exemption under 49 CFR 1150.31 to lease from O...

The phytoestrogen genistein enhances multidrug resistance in breast cancer cell lines by translational regulation of ABC transporters.

PubMed

Rigalli, Juan Pablo; Tocchetti, Guillermo Nicolás; Arana, Maite Rocío; Villanueva, Silvina Stella Maris; Catania, Viviana Alicia; Theile, Dirk; Ruiz, María Laura; Weiss, Johanna

2016-06-28

Breast cancer is the most frequent malignancy in women. Multidrug resistance due to overexpression of ABC drug transporters is a common cause of chemotherapy failure and disease recurrence. Genistein (GNT) is a phytoestrogen present in soybeans and hormone supplements. We investigated the effect of GNT on the expression and function of ABC transporters in MCF-7 and MDA-MB-231 breast cancer cell lines. Results demonstrated an induction at the protein level of ABCC1 and ABCG2 and of ABCC1 in MCF-7 and MDA-MB-231, respectively. MCF-7 cells showed a concomitant increase in doxorubicin and mitoxantrone efflux and resistance, dependent on ABCG2 activity. ABCC1 induction by GNT in MDA-MB-231 cells modified neither drug efflux nor chemoresistance due to simultaneous acute inhibition of the transporter activity by GNT. All inductions took place at the translational level, as no increment in mRNA was observed and protein increase was prevented by cycloheximide. miR-181a, already demonstrated to inhibit ABCG2 translation, was down-regulated by GNT, explaining translational induction. Effects were independent of classical estrogen receptors. Results suggest potential nutrient-drug interactions that could threaten chemotherapy efficacy, especially in ABCG2-expressing tumors treated with substrates of this transporter. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Systemic treatment in advanced biliary cancers: A multicenter Australian analysis and review.

PubMed

Brungs, Daniel; Aghmesheh, Morteza; Sjoquist, Katrin; Goldstein, David

2017-10-01

While first-line palliative chemotherapy (CT1) improves survival and quality of life in advanced biliary cancer (ABC), there is no randomized evidence to support second-line chemotherapy (CT2) in ABC. We aim to explore to role of CT2 in ABC. We performed a retrospective review of all patients who received one or more lines of chemotherapy for ABC at four Australian cancer centers between 2008 and 2011. A Cox proportional hazard model was developed to determine the impact of clinicopathologic variables on overall survival (OS) from time of progression on CT1. We identified 73 patients who received palliative chemotherapy for ABC. Twenty-five patients (34%) received two or more lines of chemotherapy. Patients with a preserved performance status on progression on first-line chemotherapy (CT1) were more likely to receive second-line chemotherapy (CT2) (P < 0.001). Disease control rate with CT2 was 36%, and mean progression-free survival was 3.2 months (95% confidence interval 1.5-4.9 months). The following variables were significant in the univariate analysis of OS from time of progression on CT1: lines of chemotherapy (P = 0.0001), Eastern Cooperative Oncology Group performance status at progression on CT1 (P < 0.0001) and disease control with CT1 (P = 0.027). Lines of chemotherapy received and performance status remained significant in the multivariate analysis for OS from progression on CT1. Second-line chemotherapy is feasible in a subset of patients with ABC. Even after accounting for confounding variables, CT2 appears to increase OS in ABC, although we are unable to exclude other unmeasured factors such as tumor biology. These findings warrant further evaluation with prospective trials. © 2016 John Wiley & Sons Australia, Ltd.

A novel cell division factor from tobacco 2B-13 cells that induced cell division in auxin-starved tobacco BY-2 cells

NASA Astrophysics Data System (ADS)

Shimizu, Takashi; Eguchi, Kentaro; Nishida, Ikuo; Laukens, Kris; Witters, Erwin; van Onckelen, Harry; Nagata, Toshiyuki

2006-06-01

Effects of auxin as plant hormones are widespread; in fact in almost all aspects of plant growth and development auxin plays a pivotal role. Although auxin is required for propagating cell division in plant cells, its effect upon cell division is least understood. If auxin is depleted from the culture medium, cultured cells cease to divide. It has been demonstrated in this context that the addition of auxin to auxin-starved nondividing tobacco BY-2 cells induced semisynchronous cell division. On the other hand, there are some cell lines, named habituated cells, that can grow without auxin. The cause and reason for the habituated cells have not been clarified. A habituated cell line named 2B-13 is derived from the tobacco BY-2 cell line, which has been most intensively studied among plant cell lines. When we tried to find the difference between two cell lines of BY-2 and 2B-13 cells, we found that the addition of culture filtrated from the auxin-habituated 2B-13 cells induced semisynchronous cell division in auxin-starved BY-2 cells. The cell division factor (CDF) that is responsible for inducing cell division in auxin-starved BY-2 cells was purified to near-homogeneity by sequential passage through a hydroxyapatite column, a ConA Sepharose column and a Sephadex gel filtration column. The resulting purified fraction appeared as a single band of high molecular weight on sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels by silver staining and was able to induce cell division in auxin-starved BY-2 cells. Identification of the protein by MALD-TOF-MS/MS revealed that it is structurally related to P-glycoprotein from Gossypioides kirkii, which belongs to ATP-binding cassette (ABC)-transporters. The significance of CDF as a possible ABC-transporter is discussed in relationship to auxin-autotrophic growth and auxin-signaling pathway.

FOXP2-positive diffuse large B-cell lymphomas exhibit a poor response to R-CHOP therapy and distinct biological signatures

PubMed Central

Wong, Kah Keng; Gascoyne, Duncan M.; Soilleux, Elizabeth J.; Lyne, Linden; Spearman, Hayley; Roncador, Giovanna; Pedersen, Lars M.; Møller, Michael B.; Green, Tina M.; Banham, Alison H.

2016-01-01

FOXP2 shares partially overlapping normal tissue expression and functionality with FOXP1; an established diffuse large B-cell lymphoma (DLBCL) oncogene and marker of poor prognosis. FOXP2 is expressed in the plasma cell malignancy multiple myeloma but has not been studied in DLBCL, where a poor prognosis activated B-cell (ABC)-like subtype display partially blocked plasma cell differentiation. FOXP2 protein expression was detected in ABC-DLBCL cell lines, and in primary DLBCL samples tumoral FOXP2 protein expression was detected in both germinal center B-cell-like (GCB) and non-GCB DLBCL. In biopsies from DLBCL patients treated with immunochemotherapy (R-CHOP), ≥ 20% nuclear tumoral FOXP2-positivity (n = 24/158) correlated with significantly inferior overall survival (OS: P = 0.0017) and progression-free survival (PFS: P = 0.0096). This remained significant in multivariate analysis against either the international prognostic index score or the non-GCB DLBCL phenotype (P < 0.05 for both OS and PFS). Expression of BLIMP1, a marker of plasmacytic differentiation that is commonly inactivated in ABC-DLBCL, did not correlate with patient outcome or FOXP2 expression in this series. Increased frequency of FOXP2 expression significantly correlated with FOXP1-positivity (P = 0.0187), and FOXP1 co-immunoprecipitated FOXP2 from ABC-DLBCL cells indicating that these proteins can co-localize in a multi-protein complex. FOXP2-positive DLBCL had reduced expression of HIP1R (P = 0.0348), which is directly repressed by FOXP1, and exhibited distinct patterns of gene expression. Specifically in ABC-DLBCL these were associated with lower expression of immune response and T-cell receptor signaling pathways. Further studies are warranted to investigate the potential functional cooperativity between FOXP1 and FOXP2 in repressing immune responses during the pathogenesis of high-risk DLBCL. PMID:27224915

FOXP2-positive diffuse large B-cell lymphomas exhibit a poor response to R-CHOP therapy and distinct biological signatures.

PubMed

Wong, Kah Keng; Gascoyne, Duncan M; Soilleux, Elizabeth J; Lyne, Linden; Spearman, Hayley; Roncador, Giovanna; Pedersen, Lars M; Møller, Michael B; Green, Tina M; Banham, Alison H

2016-08-16

FOXP2 shares partially overlapping normal tissue expression and functionality with FOXP1; an established diffuse large B-cell lymphoma (DLBCL) oncogene and marker of poor prognosis. FOXP2 is expressed in the plasma cell malignancy multiple myeloma but has not been studied in DLBCL, where a poor prognosis activated B-cell (ABC)-like subtype display partially blocked plasma cell differentiation. FOXP2 protein expression was detected in ABC-DLBCL cell lines, and in primary DLBCL samples tumoral FOXP2 protein expression was detected in both germinal center B-cell-like (GCB) and non-GCB DLBCL. In biopsies from DLBCL patients treated with immunochemotherapy (R-CHOP), ≥ 20% nuclear tumoral FOXP2-positivity (n = 24/158) correlated with significantly inferior overall survival (OS: P = 0.0017) and progression-free survival (PFS: P = 0.0096). This remained significant in multivariate analysis against either the international prognostic index score or the non-GCB DLBCL phenotype (P < 0.05 for both OS and PFS). Expression of BLIMP1, a marker of plasmacytic differentiation that is commonly inactivated in ABC-DLBCL, did not correlate with patient outcome or FOXP2 expression in this series. Increased frequency of FOXP2 expression significantly correlated with FOXP1-positivity (P = 0.0187), and FOXP1 co-immunoprecipitated FOXP2 from ABC-DLBCL cells indicating that these proteins can co-localize in a multi-protein complex. FOXP2-positive DLBCL had reduced expression of HIP1R (P = 0.0348), which is directly repressed by FOXP1, and exhibited distinct patterns of gene expression. Specifically in ABC-DLBCL these were associated with lower expression of immune response and T-cell receptor signaling pathways. Further studies are warranted to investigate the potential functional cooperativity between FOXP1 and FOXP2 in repressing immune responses during the pathogenesis of high-risk DLBCL.

Immunotechnology: Preparation of Immunotherapeutic Reagents and Development of Immunopharmacologic Vaccines.

DTIC Science & Technology

1981-10-01

Cryopreservation and HLA Typing of the Panel We have assembled a group of volunteer and paid blood donors, some of whom have been selected on the basis of...reagents used as controls. The cell donor panel is typed for human histocompatibility antigens. Dr. A.H. Johnson determines the HLA -A,B,C phenotypes and Dr...2 microglobulin and anti- HLA antibodies. Screening the fusions on glutaraldehyde fixed monolayers of B lymphoblastoid lines, T cell leukaemic lines

Loss of plastoglobule kinases ABC1K1 and ABC1K3 causes conditional degreening, modified prenyl-lipids, and recruitment of the jasmonic acid pathway

USDA-ARS?s Scientific Manuscript database

Plastoglobules (PGs) are plastid lipid-protein particles. This study examines the function of PG-localized kinases ABC1K1 and ABC1K3 in Arabidopsis thaliana. Several lines of evidence suggested that ABC1K1 and ABC1K3 form a protein complex. Null mutants for both genes (abc1k1 and abc1k3) and the dou...

Rational Targeting of Cellular Cholesterol in Diffuse Large B-Cell Lymphoma (DLBCL) Enabled by Functional Lipoprotein Nanoparticles: A Therapeutic Strategy Dependent on Cell of Origin.

PubMed

Rink, Jonathan S; Yang, Shuo; Cen, Osman; Taxter, Tim; McMahon, Kaylin M; Misener, Sol; Behdad, Amir; Longnecker, Richard; Gordon, Leo I; Thaxton, C Shad

2017-11-06

Cancer cells have altered metabolism and, in some cases, an increased demand for cholesterol. It is important to identify novel, rational treatments based on biology, and cellular cholesterol metabolism as a potential target for cancer is an innovative approach. Toward this end, we focused on diffuse large B-cell lymphoma (DLBCL) as a model because there is differential cholesterol biosynthesis driven by B-cell receptor (BCR) signaling in germinal center (GC) versus activated B-cell (ABC) DLBCL. To specifically target cellular cholesterol homeostasis, we employed high-density lipoprotein-like nanoparticles (HDL NP) that can generally reduce cellular cholesterol by targeting and blocking cholesterol uptake through the high-affinity HDL receptor, scavenger receptor type B-1 (SCARB1). As we previously reported, GC DLBCL are exquisitely sensitive to HDL NP as monotherapy, while ABC DLBCL are less sensitive. Herein, we report that enhanced BCR signaling and resultant de novo cholesterol synthesis in ABC DLBCL drastically reduces the ability of HDL NPs to reduce cellular cholesterol and induce cell death. Therefore, we combined HDL NP with the BCR signaling inhibitor ibrutinib and the SYK inhibitor R406. By targeting both cellular cholesterol uptake and BCR-associated de novo cholesterol synthesis, we achieved cellular cholesterol reduction and induced apoptosis in otherwise resistant ABC DLBCL cell lines. These results in lymphoma demonstrate that reduction of cellular cholesterol is a powerful mechanism to induce apoptosis. Cells rich in cholesterol require HDL NP therapy to reduce uptake and molecularly targeted agents that inhibit upstream pathways that stimulate de novo cholesterol synthesis, thus, providing a new paradigm for rationally targeting cholesterol metabolism as therapy for cancer.

Mechanisms of Drug Resistance in Veterinary Oncology—A Review with an Emphasis on Canine Lymphoma

PubMed Central

Zandvliet, Maurice; Teske, Erik

2015-01-01

Drug resistance (DR) is the major limiting factor in the successful treatment of systemic neoplasia with cytotoxic chemotherapy. DR can be either intrinsic or acquired, and although the development and clinical implications are different, the underlying mechanisms are likely to be similar. Most causes for DR are pharmacodynamic in nature, result from adaptations within the tumor cell and include reduced drug uptake, increased drug efflux, changes in drug metabolism or drug target, increased capacity to repair drug-induced DNA damage or increased resistance to apoptosis. The role of active drug efflux transporters, and those of the ABC-transporter family in particular, have been studied extensively in human oncology and to a lesser extent in veterinary medicine. Methods reported to assess ABC-transporter status include detection of the actual protein (Western blot, immunohistochemistry), mRNA or ABC-transporter function. The three major ABC-transporters associated with DR in human oncology are ABCB1 or P-gp, ABCC1 or MRP1, and ABCG2 or BCRP, and have been demonstrated in canine cell lines, healthy dogs and dogs with cancer. Although this supports a causative role for these ABC-transporters in DR cytotoxic agents in the dog, the relative contribution to the clinical phenotype of DR in canine cancer remains an area of debate and requires further prospective studies. PMID:29061939

Combination of Ibrutinib and ABT-199 in Diffuse Large B-Cell Lymphoma and Follicular Lymphoma.

PubMed

Kuo, Hsu-Ping; Ezell, Scott A; Schweighofer, Karl J; Cheung, Leo W K; Hsieh, Sidney; Apatira, Mutiah; Sirisawad, Mint; Eckert, Karl; Hsu, Ssucheng J; Chen, Chun-Te; Beaupre, Darrin M; Versele, Matthias; Chang, Betty Y

2017-07-01

Diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma are the most prevalent B-lymphocyte neoplasms in which abnormal activation of the Bruton tyrosine kinase (BTK)-mediated B-cell receptor signaling pathway contributes to pathogenesis. Ibrutinib is an oral covalent BTK inhibitor that has shown some efficacy in both indications. To improve ibrutinib efficacy through combination therapy, we first investigated differential gene expression in parental and ibrutinib-resistant cell lines to better understand the mechanisms of resistance. Ibrutinib-resistant TMD8 cells had higher BCL2 gene expression and increased sensitivity to ABT-199, a BCL-2 inhibitor. Consistently, clinical samples from ABC-DLBCL patients who experienced poorer response to ibrutinib had higher BCL2 gene expression. We further demonstrated synergistic growth suppression by ibrutinib and ABT-199 in multiple ABC-DLBCL, GCB-DLBCL, and follicular lymphoma cell lines. The combination of both drugs also reduced colony formation, increased apoptosis, and inhibited tumor growth in a TMD8 xenograft model. A synergistic combination effect was also found in ibrutinib-resistant cells generated by either genetic mutation or drug treatment. Together, these findings suggest a potential clinical benefit from ibrutinib and ABT-199 combination therapy. Mol Cancer Ther; 16(7); 1246-56. ©2017 AACR . ©2017 American Association for Cancer Research.

Requirement of ABC transporter inhibition and Hoechst 33342 dye deprivation for the assessment of side population-defined C6 glioma stem cell metabolism using fluorescent probes.

PubMed

Murota, Yoshitaka; Tabu, Kouichi; Taga, Tetsuya

2016-11-04

Elucidating the precise properties of cancer stem cells (CSCs) is indispensable for the development of effective therapies against tumors, because CSCs are key drivers of tumor development, metastasis and relapse. We previously reported that the Hoechst 33342 dye-low staining side population (SP) method can enrich for CSCs in the C6 glioma cell line, and that the positively stained main population (MP) cells are non-CSCs. Presence of cancer stem-like SP cells is reported in various types of cancer. Although altered cellular energy metabolism is a hallmark of cancer, very little has been studied on the applicability of fluorescent probes for the understanding of CSC energy metabolism. The metabolic status of C6 SP and MP cells are evaluated by CellROX, MitoTracker Green (MTG) and JC-1 for cellular oxidative stress, mitochondrial amount, and mitochondrial membrane potential, respectively. SP cells were found to exhibit significantly lower fluorescent intensities of CellROX and MTG than MP cells. However, inhibition of ATP binding cassette (ABC) transporters by verapamil enhanced the intensities of these probes in SP cells to the levels similar to those in MP cells, indicating that SP cells expel the probes outside of the cells through ABC transporters. Next, SP cells were stained with JC-1 dye which exhibits membrane potential dependent accumulation in mitochondrial matrix, followed by formation of aggregates. The mitochondrial membrane potential indicated by the aggregates of JC-1 was 5.0-fold lower in SP cells than MP cells. Inhibition of ABC transporters enhanced the fluorescent intensities of the JC-1 aggregates in both SP and MP cells, the former of which was still 2.2-fold lower than the latter. This higher JC-1 signal in MP cells was further found to be due to the Hoechst 33342 dye existing in MP cells. When SP and MP cells were recultured to deprive the intracellular Hoechst 33342 dye and then stained with JC-1 in the presence of verapamil, the intensities of JC-1 aggregates in such SP and MP cells became comparable. Inhibiting ABC transporters and depriving Hoechst 33342 dye are required for the accurate assessment of side population-defined C6 glioma stem cell metabolism using fluorescent probes.

Therapeutic implications of an enriched cancer stem-like cell population in a human osteosarcoma cell line

PubMed Central

2012-01-01

Background Osteosarcoma is a bone-forming tumor of mesenchymal origin that presents a clinical pattern that is consistent with the cancer stem cell model. Cells with stem-like properties (CSCs) have been identified in several tumors and hypothesized as the responsible for the relative resistance to therapy and tumor relapses. In this study, we aimed to identify and characterize CSCs populations in a human osteosarcoma cell line and to explore their role in the responsiveness to conventional therapies. Methods CSCs were isolated from the human MNNG/HOS cell line using the sphere formation assay and characterized in terms of self-renewal, mesenchymal stem cell properties, expression of pluripotency markers and ABC transporters, metabolic activity and tumorigenicity. Cell's sensitivity to conventional chemotherapeutic agents and to irradiation was analyzed and related with cell cycle-induced alterations and apoptosis. Results The isolated CSCs were found to possess self-renewal and multipotential differentiation capabilities, express markers of pluripotent embryonic stem cells Oct4 and Nanog and the ABC transporters P-glycoprotein and BCRP, exhibit low metabolic activity and induce tumors in athymic mice. Compared with parental MNNG/HOS cells, CSCs were relatively more resistant to both chemotherapy and irradiation. None of the treatments have induced significant cell-cycle alterations and apoptosis in CSCs. Conclusions MNNG/HOS osteosarcoma cells contain a stem-like cell population relatively resistant to conventional chemotherapeutic agents and irradiation. This resistant phenotype appears to be related with some stem features, namely the high expression of the drug efflux transporters P-glycoprotein and BCRP and their quiescent nature, which may provide a biological basis for resistance to therapy and recurrence commonly observed in osteosarcoma. PMID:22475227

OsAGSW1, an ABC1-like kinase gene, is involved in the regulation of grain size and weight in rice.

PubMed

Li, Tao; Jiang, Jieming; Zhang, Shengchun; Shu, Haoran; Wang, Yaqin; Lai, Jianbin; Du, Jinju; Yang, Chengwei

2015-09-01

Grain shape and weight are two determining agronomic traits of rice yield. ABC1 (Activity of bc1 complex) is a newly found atypical kinase in plants. Here, we report on an ABC1 protein kinase gene, OsAGSW1 (ABC1-like kinase related to Grain size and Weight). Expression of OsAGSW1-GFP in rice revealed that OsAGSW1 is localized to the chloroplasts in rice. Analysis of OsAGSW1 promoter::β-glucuronidase transgenic rice indicated that this gene was highly expressed in vascular bundles in shoot, hull and caryopsis. Furthermore, OsAGSW1-RNAi and overexpressed transgenic rice lines were generated. Stable transgenic lines overexpressing OsAGSW1 exhibited a phenotype with a significant increase in grain size, grain weight, grain filling rate and 1000-grain weight compared with the wild-type and RNAi transgenic plants. Microscopy analysis showed that spikelet hulls just before heading were different in the OsAGSW1-overexpressed plants compared with wild-type and OsAGSW1 RNAi rice. Further cytological analysis showed that the number of external parenchyma cells in rice hulls of OsAGSW1-overexpressed plants increased, leading to wider and longer spikelet hulls than those of the wild-type and OsAGSW1-RNAi plants. The vascular cross-sectional area in lemma, carpopodium and ovules also strikingly increased and area of both xylem and phloem were enlarged in the OsAGSW1-overexpressed plants. Thus, our results demonstrated that OsAGSW1 plays an important role in seed shape and size of rice by regulating the number of external parenchyma cells and the development of vascular bundles, providing a new insight into the functions of ABC1 genes in plants. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Increasing the cytotoxicity of doxorubicin in breast cancer MCF-7 cells with multidrug resistance using a mesoporous silica nanoparticle drug delivery system.

PubMed

Wang, Xin; Teng, Zhaogang; Wang, Haiyan; Wang, Chunyan; Liu, Ying; Tang, Yuxia; Wu, Jiang; Sun, Jin; Wang, Hai; Wang, Jiandong; Lu, Guangming

2014-01-01

Resistance to cytotoxic chemotherapy is the main cause of therapeutic failure and death in women with breast cancer. Overexpression of various members of the superfamily of adenosine triphosphate binding cassette (ABC)-transporters has been shown to be associated with multidrug resistance (MDR) phenotype in breast cancer cells. MDR1 protein promotes the intracellular efflux of drugs. A novel approach to address cancer drug resistance is to take advantage of the ability of nanocarriers to sidestep drug resistance mechanisms by endosomal delivery of chemotherapeutic agents. Doxorubicin (DOX) is an anthracycline antibiotic commonly used in breast cancer chemotherapy and a substrate for ABC-mediated drug efflux. In the present study, we developed breast cancer MCF-7 cells with overexpression of MDR1 and designed mesoporous silica nanoparticles (MSNs) which were used as a drug delivery system. We tested the efficacy of DOX in the breast cancer cell line MCF-7/MDR1 and in a MCF-7/MDR1 xenograft nude mouse model using the MSNs drug delivery system. Our data show that drug resistance in the human breast cancer cell line MCF-7/MDR1 can be overcome by treatment with DOX encapsulated within mesoporous silica nanoparticles.

[Role of let-7 in maintaining characteristics of breast cancer stem cells].

PubMed

Sun, Xin; Fan, Chong; Hu, Li-juan; Du, Ning; Xu, Chong-wen; Ren, Hong

2012-08-01

To observe the expression of let-7 in breast cancer stem cells and explore the role of let-7 in maintaining the characteristics of breast cancer stem cells. We separated breast cancer stem cells (SP and NSP) from MCF-7 cell line using SP sorting, and observed the expression of let-7a/b/c on SP and NSP cells using quantitative real-time PCR and the expressions of Ras and ERK using Western blotting to study the mechanism by which let-7 maintains the characteristics of breast cancer stem cells. The SP cells accounted for 3.3% in MCF-7 cells, however, the rate dropped to 0.4% when verapamil was added into the process of seperation. The level of Let-7a/b/c in SP cells were lower than that in NSP cells, and among let-7 miRNAs, let-7b/c showed the most obvious difference. The expressions of t-Ras and t-ERK showed no difference between SP and NSP cells, nevertheless, the expressions of p-Ras, p-ERK were higher in SP cells than in NSP cells. SP sorting is an effective method to separate cancer stem cells. There do exist cancer stem cells in MCF-7 breast cancer cell line. Let-7 is down-regulated in SP cells, and the down-regulation makes let-7 lose the opportunity to restrain Ras mRNA, finally, p-Ras and p-ERK are activated. They play an important role in maintaining the characteristics of breast cancer stem cells.

ABCE1 is essential for S phase progression in human cells

PubMed Central

Toompuu, Marina; Kärblane, Kairi; Pata, Pille; Truve, Erkki; Sarmiento, Cecilia

2016-01-01

ABSTRACT ABCE1 is a highly conserved protein universally present in eukaryotes and archaea, which is crucial for the viability of different organisms. First identified as RNase L inhibitor, ABCE1 is currently recognized as an essential translation factor involved in several stages of eukaryotic translation and ribosome biogenesis. The nature of vital functions of ABCE1, however, remains unexplained. Here, we study the role of ABCE1 in human cell proliferation and its possible connection to translation. We show that ABCE1 depletion by siRNA results in a decreased rate of cell growth due to accumulation of cells in S phase, which is accompanied by inefficient DNA synthesis and reduced histone mRNA and protein levels. We infer that in addition to the role in general translation, ABCE1 is involved in histone biosynthesis and DNA replication and therefore is essential for normal S phase progression. In addition, we analyze whether ABCE1 is implicated in transcript-specific translation via its association with the eIF3 complex subunits known to control the synthesis of cell proliferation-related proteins. The expression levels of a few such targets regulated by eIF3A, however, were not consistently affected by ABCE1 depletion. PMID:26985706

Regulation of Human γδ T Cells by BTN3A1 Protein Stability and ATP-Binding Cassette Transporters

PubMed Central

Rhodes, David A.; Chen, Hung-Chang; Williamson, James C.; Hill, Alfred; Yuan, Jack; Smith, Sam; Rhodes, Harriet; Trowsdale, John; Lehner, Paul J.; Herrmann, Thomas; Eberl, Matthias

2018-01-01

Activation of human Vγ9/Vδ2 T cells by “phosphoantigens” (pAg), the microbial metabolite (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP) and the endogenous isoprenoid intermediate isopentenyl pyrophosphate, requires expression of butyrophilin BTN3A molecules by presenting cells. However, the precise mechanism of activation of Vγ9/Vδ2 T cells by BTN3A molecules remains elusive. It is not clear what conformation of the three BTN3A isoforms transmits activation signals nor how externally delivered pAg accesses the cytosolic B30.2 domain of BTN3A1. To approach these problems, we studied two HLA haplo-identical HeLa cell lines, termed HeLa-L and HeLa-M, which showed marked differences in pAg-dependent stimulation of Vγ9/Vδ2 T cells. Levels of IFN-γ secretion by Vγ9/Vδ2 T cells were profoundly increased by pAg loading, or by binding of the pan-BTN3A specific agonist antibody CD277 20.1, in HeLa-M compared to HeLa-L cells. IL-2 production from a murine hybridoma T cell line expressing human Vγ9/Vδ2 T cell receptor (TCR) transgenes confirmed that the differential responsiveness to HeLa-L and HeLa-M was TCR dependent. By tissue typing, both HeLa lines were shown to be genetically identical and full-length transcripts of the three BTN3A isoforms were detected in equal abundance with no sequence variation. Expression of BTN3A and interacting molecules, such as periplakin or RhoB, did not account for the functional variation between HeLa-L and HeLa-M cells. Instead, the data implicate a checkpoint controlling BTN3A1 stability and protein trafficking, acting at an early time point in its maturation. In addition, plasma membrane profiling was used to identify proteins upregulated in HMB-PP-treated HeLa-M. ABCG2, a member of the ATP-binding cassette (ABC) transporter family was the most significant candidate, which crucially showed reduced expression in HeLa-L. Expression of a subset of ABC transporters, including ABCA1 and ABCG1, correlated with efficiency of T cell activation by cytokine secretion, although direct evidence of a functional role was not obtained by knockdown experiments. Our findings indicate a link between members of the ABC protein superfamily and the BTN3A-dependent activation of γδ T cells by endogenous and exogenous pAg. PMID:29670629

Cytotoxicity of South-African medicinal plants towards sensitive and multidrug-resistant cancer cells.

PubMed

Saeed, Mohamed E M; Meyer, Marion; Hussein, Ahmed; Efferth, Thomas

2016-06-20

Traditional medicine plays a major role for primary health care worldwide. Cancer belongs to the leading disease burden in industrialized and developing countries. Successful cancer therapy is hampered by the development of resistance towards established anticancer drugs. In the present study, we investigated the cytotoxicity of 29 extracts from 26 medicinal plants of South-Africa against leukemia cell lines, most of which are used traditionally to treat cancer and related symptoms. We have investigated the plant extracts for their cytotoxic activity towards drug-sensitive parental CCRF-CEM leukemia cells and their multidrug-resistant P-glycoprotein-overexpressing subline, CEM/ADR5000 by means of the resazurin assay. A panel of 60 NCI tumor cell lines have been investigated for correlations between selected phytochemicals from medicinal plants and the expression of resistance-conferring genes (ABC-transporters, oncogenes, tumor suppressor genes). Seven extracts inhibited both cell lines (Acokanthera oppositifolia, Hypoestes aristata, Laurus nobilis, Leonotis leonurus, Plectranthus barbatus, Plectranthus ciliates, Salvia apiana). CEM/ADR5000 cells exhibited a low degree of cross-resistance (3.35-fold) towards the L. leonurus extract, while no cross-resistance was observed to other plant extracts, although CEM/ADR5000 cells were highly resistant to clinically established drugs. The log10IC50 values for two out of 14 selected phytochemicals from these plants (acovenoside A and ouabain) of 60 tumor cell lines were correlated to the expression of ABC-transporters (ABCB1, ABCB5, ABCC1, ABCG2), oncogenes (EGFR, RAS) and tumor suppressors (TP53). Sensitivity or resistance of the cell lines were not statistically associated with the expression of these genes, indicating that multidrug-resistant, refractory tumors expressing these genes may still respond to acovenoside A and ouabain. The bioactivity of South African medicinal plants may represent a basis for the development of strategies to treat multidrug-resistant tumors either by phytotherapeutic approaches with whole plant preparations or by classical drug development with isolated compounds such as acovenoside A or ouabain. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Expression and activity of multidrug resistance protein 1 in a murine thymoma cell line

PubMed Central

Echevarria-Lima, Juliana; Kyle-Cezar, Fernanda; Leite, Daniela F P; Capella, Luiz; Capella, Márcia A M; Rumjanek, Vivian M

2005-01-01

Multidrug resistance proteins [MRPs and P-glycoprotein (Pgp)] are members of the family of ATP-binding cassette (ABC) transport proteins, originally described as being involved in the resistance against anti-cancer agents in tumour cells. These proteins act as ATP-dependent efflux pumps and have now been described in normal cells where they exert physiological roles. The aim of this work was to investigate the expression and activity of MRP and Pgp in the thymoma cell line, EL4. It was observed that EL4 cells expressed mRNA for MRP1, but not for MRP2, MRP3 or Pgp. The activity of ABC transport proteins was evaluated by using the efflux of the fluorescent probes carboxy-2′-7′-dichlorofluorescein diacetate (CFDA) and rhodamine 123 (Rho 123). EL4 cells did not retain CFDA intracellularly, and MRP inhibitors (probenecid, indomethacin and MK 571) decreased MRP1 activity in a concentration-dependent manner. As expected, EL4 cells accumulated Rho 123, and the presence of cyclosporin A and verapamil did not modify this accumulation. Most importantly, when EL4 cells were incubated in the presence of the MRP1 inhibitors indomethacin and MK 571 for 6 days, they started to express CD4 and CD8 molecules on their surface, producing double-positive cells and CD8 single-positive cells. Our results suggest that MRP activity is important for the maintenance of the undifferentiated state in this cell type. This finding might have implications in the physiological process of normal thymocyte maturation. PMID:15804283

Hospicells promote upregulation of the ATP-binding cassette genes by insulin-like growth factor-I via the JAK2/STAT3 signaling pathway in an ovarian cancer cell line.

PubMed

Benabbou, Nadia; Mirshahi, Pezhman; Cadillon, Mélodie; Soria, Jeannette; Therwath, Amu; Mirshahi, Massoud

2013-09-01

Interaction between tumor cells and their micro-environment has a crucial role in the development, progression and drug resistance of cancer. Our objective was to confirm the role of Hospicells, which are stromal cells from the cancer microenvironment, in drug resistance and tumor cell growth. We demonstrated that soluble factors secreted by Hospicells activate several genes and upregulate the JAK/STAT signaling pathway in ovarian cancer cell lines. Hospicells express all insulin-like growth factor (IGF) family as detected by gene array, RT-PCR, protein array and immunocytochemistry. While focusing attention on the microenvironment, we considered the role of IGF-I in proliferation and survival of ovarian cancer cells. Indeed, IGF-I is a major regulator of different stages of cancer development. We studied the effect of exogenously added IGF-I on the regulation of ATP-binding cassette (ABC) genes (MDR1, MRP1, MRP2, MRP3, MRP5 and BCRP) in the ovarian cancer cell line OVCAR3 and validated the results obtained using the IGF-IR antagonist picropodophyllin. IGF-I regulates the expression of ABC genes in OVCAR3 cells via the PI3-kinase, MEK and JAK2/STAT3 signaling pathways. The OVCAR3 cell line when co-cultured with Hospicells showed a marked degree of drug resistance. The drug resistance observed could be amplified with exogenous IGF-I. Addition of IGF-IR inhibitor, however, reduced the degree of resistance in these exposed cells. Cells that were treated with anticancer drugs and then exposed to IGF-I showed an increase in drug resistance and, thereby, an increase in cell survival. This observation indicates that drug resistance of OVCAR3 cells increases when there is synergy between OVCAR3 cells and Hospicells and it is amplified when IGF-I was exogenously added. In conclusion, inhibition of IGF-IR and targeting of the JAK2/STAT3 signaling pathway can be a target for ovarian cancer therapy.

Hospicells promote upregulation of the ATP-binding cassette genes by insulin-like growth factor-I via the JAK2/STAT3 signaling pathway in an ovarian cancer cell line

PubMed Central

BENABBOU, NADIA; MIRSHAHI, PEZHMAN; CADILLON, MÉLODIE; SORIA, JEANNETTE; THERWATH, AMU; MIRSHAHI, MASSOUD

2013-01-01

Interaction between tumor cells and their microenvironment has a crucial role in the development, progression and drug resistance of cancer. Our objective was to confirm the role of Hospicells, which are stromal cells from the cancer microenvironment, in drug resistance and tumor cell growth. We demonstrated that soluble factors secreted by Hospicells activate several genes and upregulate the JAK/STAT signaling pathway in ovarian cancer cell lines. Hospicells express all insulin-like growth factor (IGF) family as detected by gene array, RT-PCR, protein array and immunocytochemistry. While focusing attention on the microenvironment, we considered the role of IGF-I in proliferation and survival of ovarian cancer cells. Indeed, IGF-I is a major regulator of different stages of cancer development. We studied the effect of exogenously added IGF-I on the regulation of ATP-binding cassette (ABC) genes (MDR1, MRP1, MRP2, MRP3, MRP5 and BCRP) in the ovarian cancer cell line OVCAR3 and validated the results obtained using the IGF-IR antagonist picropodophyllin. IGF-I regulates the expression of ABC genes in OVCAR3 cells via the PI3-kinase, MEK and JAK2/STAT3 signaling pathways. The OVCAR3 cell line when co-cultured with Hospicells showed a marked degree of drug resistance. The drug resistance observed could be amplified with exogenous IGF-I. Addition of IGF-IR inhibitor, however, reduced the degree of resistance in these exposed cells. Cells that were treated with anticancer drugs and then exposed to IGF-I showed an increase in drug resistance and, thereby, an increase in cell survival. This observation indicates that drug resistance of OVCAR3 cells increases when there is synergy between OVCAR3 cells and Hospicells and it is amplified when IGF-I was exogenously added. In conclusion, inhibition of IGF-IR and targeting of the JAK2/STAT3 signaling pathway can be a target for ovarian cancer therapy. PMID:23857432

Aberrant immunoglobulin class switch recombination and switch translocations in activated B cell-like diffuse large B cell lymphoma.

PubMed

Lenz, Georg; Nagel, Inga; Siebert, Reiner; Roschke, Anna V; Sanger, Warren; Wright, George W; Dave, Sandeep S; Tan, Bruce; Zhao, Hong; Rosenwald, Andreas; Muller-Hermelink, Hans Konrad; Gascoyne, Randy D; Campo, Elias; Jaffe, Elaine S; Smeland, Erlend B; Fisher, Richard I; Kuehl, W Michael; Chan, Wing C; Staudt, Louis M

2007-03-19

To elucidate the mechanisms underlying chromosomal translocations in diffuse large B cell lymphoma (DLBCL), we investigated the nature and extent of immunoglobulin class switch recombination (CSR) in these tumors. We used Southern blotting to detect legitimate and illegitimate CSR events in tumor samples of the activated B cell-like (ABC), germinal center B cell-like (GCB), and primary mediastinal B cell lymphoma (PMBL) subgroups of DLBCL. The frequency of legitimate CSR was lower in ABC DLBCL than in GCB DLBCL and PMBL. In contrast, ABC DLBCL had a higher frequency of internal deletions within the switch mu (Smu) region compared with GCB DLBCL and PMBL. ABC DLBCLs also had frequent deletions within Sgamma and other illegitimate switch recombinations. Sequence analysis revealed ongoing Smu deletions within ABC DLBCL tumor clones, which were accompanied by ongoing duplications and activation-induced cytidine deaminase-dependent somatic mutations. Unexpectedly, short fragments derived from multiple chromosomes were interspersed within Smu in one case. These findings suggest that ABC DLBCLs have abnormalities in the regulation of CSR that could predispose to chromosomal translocations. Accordingly, aberrant switch recombination was responsible for translocations in ABC DLBCLs involving BCL6, MYC, and a novel translocation partner, SPIB.

Activation of the STAT3 Signaling Pathway Is Associated With Poor Survival in Diffuse Large B-Cell Lymphoma Treated With R-CHOP

PubMed Central

Huang, Xin; Meng, Bin; Iqbal, Javeed; Ding, B. Belinda; Perry, Anamarija M.; Cao, Wenfeng; Smith, Lynette M.; Bi, Chengfeng; Jiang, Chunsun; Greiner, Timothy C.; Weisenburger, Dennis D.; Rimsza, Lisa; Rosenwald, Andreas; Ott, German; Delabie, Jan; Campo, Elias; Braziel, Rita M.; Gascoyne, Randy D.; Cook, James R.; Tubbs, Raymond R.; Jaffe, Elaine S.; Armitage, James O.; Vose, Julie M.; Staudt, Louis M.; McKeithan, Timothy W.; Chan, Wing C.; Ye, B. Hilda; Fu, Kai

2013-01-01

Purpose We previously reported that constitutive STAT3 activation is a prominent feature of the activated B-cell subtype of diffuse large B-cell lymphomas (ABC-DLBCL). In this study, we investigated whether STAT3 activation can risk stratify patients with DLBCL. Patients and Methods By an immunohistochemical method, we investigated phosphotyrosine STAT3 (PY-STAT3) expression from 185 patients with DLBCL treated with R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone). Cell line-based siRNA experiments were also performed to generate an 11-gene, PY-STAT3 activation signature, which was used to study a previously published cohort of 222 patients with DLBCL. The STAT3 activation status determined by these two methods and by STAT3 mRNA levels were then correlated with survival. Results PY-STAT3 was detected in 37% of DLBCL and enriched in ABC-DLBCL cases (P = .03). PY-STAT3 positivity significantly correlated with poor overall survival (OS; P = .01) and event-free survival (EFS; P = .006). Similar observations were made for high levels of STAT3 mRNA. In multivariable analysis, PY-STAT3 status (P = .02), International Prognostic Index (P = .02), and BCL2 expression (P = .046) were independent prognosticators of OS in this cohort. Among the cell-of-origin subgroups, PY-STAT3 was associated with poor EFS among non–germinal center B-cell DLBCL cases only (P = .027). Similarly, the 11-gene STAT3 activation signature correlated with poor survival in the entire DLBCL cohort (OS, P < .001; EFS, P < .001) as well as the ABC-DLBCL subgroup (OS, P = .029; EFS, P = .025). Conclusion STAT3 activation correlated with poor survival in patients with DLBCL treated with R-CHOP, especially those with tumors of the ABC-DLBCL subtype. PMID:24220563

Purification and biochemical characterization of NpABCG5/NpPDR5, a plant pleiotropic drug resistance transporter expressed in Nicotiana tabacum BY-2 suspension cells.

PubMed

Toussaint, Frédéric; Pierman, Baptiste; Bertin, Aurélie; Lévy, Daniel; Boutry, Marc

2017-05-04

Pleiotropic drug resistance (PDR) transporters belong to the ABCG subfamily of ATP-binding cassette (ABC) transporters and are involved in the transport of various molecules across plasma membranes. During evolution, PDR genes appeared independently in fungi and in plants from a duplication of a half-size ABC gene. The enzymatic properties of purified PDR transporters from yeast have been characterized. This is not the case for any plant PDR transporter, or, incidentally, for any purified plant ABC transporter. Yet, plant PDR transporters play important roles in plant physiology such as hormone signaling or resistance to pathogens or herbivores. Here, we describe the expression, purification, enzymatic characterization and 2D analysis by electron microscopy of NpABCG5/NpPDR5 from Nicotiana plumbaginifolia , which has been shown to be involved in the plant defense against herbivores. We constitutively expressed NpABCG5/NpPDR5, provided with a His-tag in a homologous system: suspension cells from Nicotiana tabacum (Bright Yellow 2 line). NpABCG5/NpPDR5 was targeted to the plasma membrane and was solubilized by dodecyl maltoside and purified by Ni-affinity chromatography. The ATP-hydrolyzing specific activity (27 nmol min -1  mg -1 ) was stimulated seven-fold in the presence of 0.1% asolectin. Electron microscopy analysis indicated that NpABCG5/NpPDR5 is monomeric and with dimensions shorter than those of known ABC transporters. Enzymatic data (optimal pH and sensitivity to inhibitors) confirmed that plant and fungal PDR transporters have different properties. These data also show that N. tabacum suspension cells are a convenient host for the purification and biochemical characterization of ABC transporters. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

Detection and functional characterization of Pgp1 (ABCB1) and MRP3 (ABCC3) efflux transporters in the PLHC-1 fish hepatoma cell line.

PubMed

Zaja, Roko; Klobucar, Roberta Sauerborn; Smital, Tvrtko

2007-03-30

The PLHC-1 hepatoma cell line derived from topminnow (Poeciliopsis lucida) is one of the most frequently used fish cell lines in aquatic ecotoxicology. These cells have been well characterized regarding the presence of phase I and phase II enzymes involved in the metabolism of xenobiotics. However, the presence of the ABC transport proteins possibly involved in the MultiXenobiotic Resistance (MXR) mechanism as phase III of cellular detoxification has never been described in the PLHC-1 cells. The main goal of this study was the detection and functional characterization of toxicologically relevant xenobiotic efflux transporters from ABCB and ABCC subfamily in the PLHC-1 cells. Using specific primer pairs two PCR products 1769 and 1023bp in length were successfully cloned and sequenced. Subsequent multiple alignment and phylogenetic analysis showed that these sequences share a high degree of homology with the P-glycoprotein (Pgp1; ABCB1) and the MRP3 (ABCC3). Functional experiments with fluorescent model substrates and specific inhibitors were used to verify that transport activities of Pgp- and MRP-related proteins are indeed present in PLHC-1 cells. Accumulation or efflux/retention rates of rhodamine 123, calcein-AM or monochlorbimane were time- and concentration-dependent. Cyclosporine A, MK571, verapamil, reversine 205, indomethacine and probenecid were used as specific inhibitors of Pgp1 and/or MRPs transport activities, resulting in a dose dependent inhibition of related transport activities in PLHC-1 cells. Similar to mammalian systems, the obtained IC(50) values were in the lower micromolar range. Taken together these data demonstrate that: (1) the PLHC-1 cells do express a functional MXR mechanism mediated by toxicologically relevant ABC efflux transporters; and (2) the presence of all three critical phases of cellular detoxification additionally affirms the PLHC-1 cells as a reliable in vitro model in aquatic toxicology.

Expression, purification and characterization of GAPDH-ChSase ABC I from Proteus vulgaris in Escherichia coli.

PubMed

Li, Ye; Chen, Zhenya; Zhou, Zhao; Yuan, Qipeng

2016-12-01

Chondroitinases (ChSases) are a family of polysaccharide lyases that can depolymerize high molecular weight chondroitin sulfate (CS) and dermatan sulfate (DS). In this study, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which is stably expressed in different cells like normal cells and cancer cells and the expression is relatively insensitive to experimental conditions, was expressed as a fusion protein with ChSase ABC I. Results showed that the expression level and enzyme activity of GAPDH-ChSase ABC I were about 2.2 and 3.0 times higher than those of ChSase ABC I. By optimization of fermentation conditions, higher productivity of ChSase ABC I was achieved as 880 ± 61 IU/g wet cell weight compared with the reported ones. The optimal temperature and pH of GAPDH-ChSase ABC I were 40 °C and 7.5, respectively. GAPDH-ChSase ABC I had a kcat/Km of 131 ± 4.1 L/μmol s and the catalytic efficiency was decreased as compared to ChSase ABC I. The relative activity of GAPDH-ChSase ABC I remained 89% after being incubated at 30 °C for 180 min and the thermostability of ChSase ABC I was enhanced by GAPDH when it was incubated at 30, 35, 40 and 45 °C. Copyright © 2016 Elsevier Inc. All rights reserved.

The Role of Activity Based Costing (ABC) in Educational Support Services: A White Paper.

ERIC Educational Resources Information Center

Edds, Daniel B.

Many front-line managers who are assuming more financial responsibility for their organizations find traditional cost accounting inadequate for their needs and are turning to Activity Based Costing (ABC). ABC is not a financial reporting system to serve the needs of regulatory agencies, but a tool that tracks costs from the general ledger…

Identification of drug-resistant subpopulations in canine hemangiosarcoma

PubMed Central

Khammanivong, A.; Gorden, B. H.; Frantz, A. M.; Graef, A. J.; Dickerson, E. B.

2017-01-01

Canine hemangiosarcoma is a rapidly progressive disease that is poorly responsive to conventional chemotherapy. Despite numerous attempts to advance treatment options and improve outcomes, drug resistance remains a hurdle to successful therapy. To address this problem, we used recently characterized progenitor cell populations derived from canine hemangiosarcoma cell lines and grown as non-adherent spheres to identify potential drug resistance mechanisms as well as drug-resistant cell populations. Cells from sphere-forming cultures displayed enhanced resistance to chemotherapy drugs, expansion of dye-excluding side populations and altered ATP-binding cassette (ABC) transporter expression. Invasion studies demonstrated variability between cell lines as well as between sphere and monolayer cell populations. Collectively, our results suggest that sphere cell populations contain distinct subpopulations of drug-resistant cells that utilize multiple mechanisms to evade cytotoxic drugs. Our approach represents a new tool for the study of drug resistance in hemangiosarcoma, which could alter approaches for treating this disease. PMID:25112808

Targeting receptor-activator of nuclear kappaB ligand in aneurysmal bone cysts: verification of target and therapeutic response.

PubMed

Pelle, Dominic W; Ringler, Jonathan W; Peacock, Jacqueline D; Kampfschulte, Kevin; Scholten, Donald J; Davis, Mary M; Mitchell, Deanna S; Steensma, Matthew R

2014-08-01

Aneurysmal bone cyst (ABC) is a benign tumor of bone presenting as a cystic, expansile lesion in both the axial and appendicular skeleton. Axial lesions demand special consideration, because treatment-related morbidity can be devastating. In similar lesions, such as giant cell tumor of bone (GCTB), the receptor-activator of nuclear kappaB ligand (RANKL)-receptor-activator of nuclear kappaB (RANK) signaling axis is essential to tumor progression. Although ABC and GCTB are distinct entities, they both contain abundant multinucleated giant cells and are osteolytic characteristically. We hypothesize that ABCs express both RANKL and RANK similarly in a cell-type specific manner, and that targeted RANKL therapy will mitigate ABC tumor progression. Cellular expression of RANKL and RANK was determined in freshly harvested ABC samples using laser confocal microscopy. A consistent cell-type-specific pattern was observed: fibroblastlike stromal cells expressed RANKL strongly whereas monocyte/macrophage precursor and multinucleated giant cells expressed RANK. Relative RANKL expression was determined by quantitative real-time polymerase chain reaction in ABC and GCTB tissue samples; no difference in relative expression was observed (P > 0.05). In addition, we review the case of a 5-year-old boy with a large, aggressive sacral ABC. After 3 months of targeted RANKL inhibition with denosumab, magnetic resonance imaging demonstrated tumor shrinkage, bone reconstitution, and healing of a pathologic fracture. Ambulation, and bowel and bladder function were restored at 6 months. Denosumab treatment was well tolerated. Post hoc analysis demonstrated strong RANKL expression in the pretreatment tumor sample. These findings demonstrate that RANKL-RANK signal activation is essential to ABC tumor progression. RANKL-targeted therapy may be an effective alternative to surgery in select ABC presentations. Copyright © 2014 Mosby, Inc. All rights reserved.

Piperine, a piperidine alkaloid from Piper nigrum re-sensitizes P-gp, MRP1 and BCRP dependent multidrug resistant cancer cells.

PubMed

Li, Sen; Lei, Yu; Jia, Yingjie; Li, Na; Wink, Michael; Ma, Yonggang

2011-12-15

Over-expression of P-gp, MRP1 and BCRP in tumor cells is one of the important mechanisms leading to multidrug resistance (MDR), which impairs the efficacy of chemotherapy. P-gp, MRP1 and BCRP are ABC (ATP-Binding Cassette) transporters, which can expel a variety of lipophilic anti-cancer drugs and protect tumor cells. During a screening of MDR reversal agents among alkaloids of various structural types, a piperidine alkaloid, piperine (a main piperidine alkaloid in Piper nigurm) was identified as an inhibitor. Piperine can potentiate the cytotoxicity of anti-cancer drugs in resistant sublines, such as MCF-7/DOX and A-549/DDP, which were derived from MCF-7 and A-549 cell lines. At a concentration of 50 μM piperine could reverse the resistance to doxorubicin 32.16 and 14.14 folds, respectively. It also re-sensitized cells to mitoxantrone 6.98 folds. In addition, long-term treatment of cells by piperine inhibits transcription of the corresponding ABC transporter genes. These results suggest that piperine can reverse MDR by multiple mechanisms and it may be a promising lead compound for future studies. Copyright © 2011 Elsevier GmbH. All rights reserved.

An ATP-driven efflux pump is a novel pathogenicity factor in rice blast disease.

PubMed Central

Urban, M; Bhargava, T; Hamer, J E

1999-01-01

Cells tolerate exposure to cytotoxic compounds through the action of ATP-driven efflux pumps belonging to the ATP-binding cassette (ABC) superfamily of membrane transporters. Phytopathogenic fungi encounter toxic environments during plant invasion as a result of the plant defense response. Here we demonstrate the requirement for an ABC transporter during host infection by the fungal plant pathogen Magnaporthe grisea. The ABC1 gene was identified in an insertional mutagenesis screen for pathogenicity mutants. The ABC1 insertional mutant and a gene-replacement mutant arrest growth and die shortly after penetrating either rice or barley epidermal cells. The ABC1-encoded protein is similar to yeast ABC transporters implicated in multidrug resistance, and ABC1 gene transcripts are inducible by toxic drugs and a rice phytoalexin. However, abc1 mutants are not hypersensitive to antifungal compounds. The non-pathogenic, insertional mutation in ABC1 occurs in the promoter region and dramatically reduces transcript induction by metabolic poisons. These data strongly suggest that M.grisea requires the up-regulation of specific ABC transporters for pathogenesis; most likely to protect itself against plant defense mechanisms. PMID:9927411

Novel Compounds Line up to Combat Drug Resistance in Cancer Cells | Center for Cancer Research

Cancer.gov

As the war on cancer has intensified and new molecular attacks on cancer cells have been developed, cancer cells have devised innovative ways of defending themselves. Many drugs have been designed or discovered and used to kill cancer cells; in response, these cells are staging new mechanisms to resist the effects of a variety of drugs, a phenomenon called multidrug resistance (MDR). One way cancer cells accomplish this is by catching the intruding drug and throwing it out of the cell before it can act. The arsenal that the cancer cell uses to accomplish this task is a collection of specialized proteins on its membrane called ATP-binding cassette (ABC) transporters.

Venetoclax Synergizes with Radiotherapy for Treatment of B-cell Lymphomas.

PubMed

O'Steen, Shyril; Green, Damian J; Gopal, Ajay K; Orozco, Johnnie J; Kenoyer, Aimee L; Lin, Yukang; Wilbur, D Scott; Hamlin, Donald K; Fisher, Darrell R; Hylarides, Mark D; Gooley, Theodore A; Waltman, Amelia; Till, Brian G; Press, Oliver W

2017-07-15

Constitutive B-cell receptor signaling leads to overexpression of the antiapoptotic BCL-2 protein and is implicated in the pathogenesis of many types of B-cell non-Hodgkin lymphoma (B-NHL). The BCL-2 small-molecule inhibitor venetoclax shows promising clinical response rates in several lymphomas, but is not curative as monotherapy. Radiotherapy is a rational candidate for combining with BCL-2 inhibition, as DNA damage caused by radiotherapy increases the activity of pro-apoptotic BCL-2 pathway proteins, and lymphomas are exquisitely sensitive to radiation. We tested B-NHL responses to venetoclax combined with either external beam radiotherapy or radioimmunotherapy (RIT), which joins the selectivity of antibody targeting with the effectiveness of irradiation. We first tested cytotoxicity of cesium-137 irradiation plus venetoclax in 14 B-NHL cell lines representing five lymphoma subtypes. Combination treatment synergistically increased cell death in 10 of 14 lines. Lack of synergy was predicted by resistance to single-agent venetoclax and high BCL-XL expression. We then assessed the efficacy of external beam radiotherapy plus venetoclax in murine xenograft models of mantle cell (MCL), germinal-center diffuse large B-cell (GCB-DLBCL), and activated B-cell (ABC-DLBCL) lymphomas. In each model, external beam radiotherapy plus venetoclax synergistically increased mouse survival time, curing up to 10%. We finally combined venetoclax treatment of MCL and ABC-DLBCL xenografts with a pretargeted RIT (PRIT) system directed against the CD20 antigen. Optimal dosing of PRIT plus venetoclax cured 100% of mice with no detectable toxicity. Venetoclax combined with radiotherapy may be a promising treatment for a wide range of lymphomas Cancer Res; 77(14); 3885-93. ©2017 AACR . ©2017 American Association for Cancer Research.

High-efficiency lysis of cervical cancer by allogeneic NK cells derived from umbilical cord progenitors is independent of HLA status.

PubMed

Veluchamy, John P; Heeren, A Marijne; Spanholtz, Jan; van Eendenburg, Jaap D H; Heideman, Daniëlle A M; Kenter, Gemma G; Verheul, Henk M; van der Vliet, Hans J; Jordanova, Ekaterina S; de Gruijl, Tanja D

2017-01-01

Down-regulation of HLA in tumor cells, low numbers and dysfunctionality of NK cells are commonly observed in patients with end-stage cervical cancer. Adoptive transfer of high numbers of cytotoxic NK cells might be a promising treatment approach in this setting. Here, we explored the cytotoxic efficacy on ten cervical cancer cell lines of activated allogeneic NK cells from two sources, i.e., peripheral blood (PBNK) with and without cetuximab (CET), a tumor-specific monoclonal antibody directed against EGFR, or derived from umbilical cord blood (UCB-NK). Whereas CET monotherapy was ineffective against the panel of cervical cancer cell lines, irrespective of their EGFR expression levels and despite their RAS wt status, it significantly enhanced the in vitro cytotoxic efficacy of activated PBNK (P = 0.002). Equally superior cytotoxicity over activated PBNK alone was achieved by UCB-NK (P < 0.001). Both PBNK- and UCB-NK-mediated cytotoxic activity was dependent on the NK-activating receptors natural killer group 2, member D receptor (NKG2D) and DNAX accessory molecule-1 (DNAM-1) (P < 0.05) and unrelated to expression levels of the inhibitory receptors HLA-E and/or HLA-G. Most strikingly, whereas the PBNK's cytotoxic activity was inversely correlated with HLA-ABC levels (P = 0.036), PBNK + CET and UCB-NK cytotoxicity were entirely independent of HLA-ABC expression. In conclusion, this study provides a rationale to initiate a clinical trial for cervical cancer with adoptively transferred allogeneic NK cells, employing either UCB-NK or PBNK + CET for EGFR-expressing tumors. Adoptive transfer of UCB-NK might serve as a generally applicable treatment for cervical cancer, enabled by HLA-, histology- and HPV-independent killing mechanisms.

Regulation of voltage-gated potassium channels attenuates resistance of side-population cells to gefitinib in the human lung cancer cell line NCI-H460.

PubMed

Choi, Seon Young; Kim, Hang-Rae; Ryu, Pan Dong; Lee, So Yeong

2017-02-21

Side-population (SP) cells that exclude anti-cancer drugs have been found in various tumor cell lines. Moreover, SP cells have a higher proliferative potential and drug resistance than main population cells (Non-SP cells). Also, several ion channels are responsible for the drug resistance and proliferation of SP cells in cancer. To confirm the expression and function of voltage-gated potassium (Kv) channels of SP cells, these cells, as well as highly expressed ATP-binding cassette (ABC) transporters and stemness genes, were isolated from a gefitinib-resistant human lung adenocarcinoma cell line (NCI-H460), using Hoechst 33342 efflux. In the present study, we found that mRNA expression of Kv channels in SP cells was different compared to Non-SP cells, and the resistance of SP cells to gefitinib was weakened with a combination treatment of gefitinib and Kv channel blockers or a Kv7 opener, compared to single-treatment gefitinib, through inhibition of the Ras-Raf signaling pathway. The findings indicate that Kv channels in SP cells could be new targets for reducing the resistance to gefitinib.

Implementation of activity-based costing (ABC) to drive cost reduction efforts in a semiconductor manufacturing operation

NASA Astrophysics Data System (ADS)

Naguib, Hussein; Bol, Igor I.; Lora, J.; Chowdhry, R.

1994-09-01

This paper presents a case study on the implementation of ABC to calculate the cost per wafer and to drive cost reduction efforts for a new IC product line. The cost reduction activities were conducted through the efforts of 11 cross-functional teams which included members of the finance, purchasing, technology development, process engineering, equipment engineering, production control, and facility groups. The activities of these cross functional teams were coordinated by a cost council. It will be shown that these activities have resulted in a 57% reduction in the wafer manufacturing cost of the new product line. Factors contributed to successful implementation of an ABC management system are discussed.

Thermo-responsive magnetic liposomes for hyperthermia-triggered local drug delivery.

PubMed

Dai, Min; Wu, Cong; Fang, Hong-Ming; Li, Li; Yan, Jia-Bao; Zeng, Dan-Lin; Zou, Tao

2017-06-01

We prepared and characterised thermo-responsive magnetic liposomes, which were designed to combine features of magnetic targeting and thermo-responsive control release for hyperthermia-triggered local drug delivery. The particle size and zeta-potential of the thermo-responsive magnetic ammonium bicarbonate (MagABC) liposomes were about 210 nm and -14 mV, respectively. The MagABC liposomes showed encapsulation efficiencies of about 15% and 82% for magnetic nanoparticles (mean crystallite size 12 nm) and doxorubicin (DOX), respectively. The morphology of the MagABC liposomes was visualised using transmission electron microscope (TEM). The MagABC liposomes showed desired thermo-responsive release. The MagABC liposomes, when physically targeted to tumour cells in culture by a permanent magnetic field yielded a substantial increase in intracellular accumulation of DOX as compared to non-magnetic ammonium bicarbonate (ABC) liposomes. This resulted in a parallel increase in cytotoxicity for DOX loaded MagABC liposomes over DOX loaded ABC liposomes in tumour cells.

[Immunohistochemical observation on keratin filaments of cultured tumor cells by ABC staining].

PubMed

Wang, J; Yang, F

1991-06-01

Avidin-Biotin Peroxidase complex technique, ABV staining, was employed by using monoclonal anti-keratin antibody HK2 in this study. The organization and dynamics of keratins in both interphase and mitotic T56 and HeLa cells were analysed. We also observed the effects of microtubule (MT) and microfilament (MF) inhibitors, colchicine and cytochalasin B, on the organization of keratin filaments in T56 and HeLa cells. The results showed that a significant alteration in the structural organization and distribution of keratin filaments occurred during mitosis, and an extensive rearrangement of keratin networks of the two cell lines was induced in interphase after the MT and MF were disrupted by combined treatment with the two drugs, colchicine and cytochalasin B; the keratin networks turned into a star-like lattice rapidly within 1-2h. Neither colchicine nor cytochalasin B alone elicited significant organizational change in the keratin networks of the two cell lines.

The mitochondrial transporter ABC-me (ABCB10), a downstream target of GATA-1, is essential for erythropoiesis in vivo.

PubMed

Hyde, B B; Liesa, M; Elorza, A A; Qiu, W; Haigh, S E; Richey, L; Mikkola, H K; Schlaeger, T M; Shirihai, O S

2012-07-01

The mitochondrial transporter ATP binding cassette mitochondrial erythroid (ABC-me/ABCB10) is highly induced during erythroid differentiation by GATA-1 and its overexpression increases hemoglobin production rates in vitro. However, the role of ABC-me in erythropoiesis in vivo is unknown. Here we report for the first time that erythrocyte development in mice requires ABC-me. ABC-me-/- mice die at day 12.5 of gestation, showing nearly complete eradication of primitive erythropoiesis and lack of hemoglobinized cells at day 10.5. ABC-me-/- erythroid cells fail to differentiate because they exhibit a marked increase in apoptosis, both in vivo and ex vivo. Erythroid precursors are particularly sensitive to oxidative stress and ABC-me in the heart and its yeast ortholog multidrug resistance-like 1 have been shown to protect against oxidative stress. Thus, we hypothesized that increased apoptosis in ABC-me-/- erythroid precursors was caused by oxidative stress. Within this context, ABC-me deletion causes an increase in mitochondrial superoxide production and protein carbonylation in erythroid precursors. Furthermore, treatment of ABC-me-/- erythroid progenitors with the mitochondrial antioxidant MnTBAP (superoxide dismutase 2 mimetic) supports survival, ex vivo differentiation and increased hemoglobin production. Altogether, our findings demonstrate that ABC-me is essential for erythropoiesis in vivo.

Degree of Suppression of Mouse Myoblast Cell Line C₂C12 Differentiation Varies According to Chondroitin Sulfate Subtype.

PubMed

Warita, Katsuhiko; Oshima, Nana; Takeda-Okuda, Naoko; Tamura, Jun-Ichi; Hosaka, Yoshinao Z

2016-10-21

Chondroitin sulfate (CS), a type of glycosaminoglycan (GAG), is a factor involved in the suppression of myogenic differentiation. CS comprises two repeating sugars and has different subtypes depending on the position and number of bonded sulfate groups. However, the effect of each subtype on myogenic differentiation remains unclear. In this study, we spiked cultures of C₂C 12 myoblasts, cells which are capable of undergoing skeletal muscle differentiation, with one of five types of CS (CS-A, -B, -C, -D, or -E) and induced differentiation over a fixed time. After immunostaining of the formed myotubes with an anti-MHC antibody, we counted the number of nuclei in the myotubes and then calculated the fusion index (FI) as a measure of myotube differentiation. The FI values of all the CS-treated groups were lower than the FI value of the control group, especially the group treated with CS-E, which displayed notable suppression of myotube formation. To confirm that the sugar chain in CS-E is important in the suppression of differentiation, chondroitinase ABC (ChABC), which catabolizes CS, was added to the media. The addition of ChABC led to the degradation of CS-E, and neutralized the suppression of myotube formation by CS-E. Collectively, it can be concluded that the degree of suppression of differentiation depends on the subtype of CS and that CS-E strongly suppresses myogenic differentiation. We conclude that the CS sugar chain has inhibitory action against myoblast cell fusion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niu, Mingshan; Jiangsu Key Laboratory of Bone Marrow Stem Cell, Xuzhou Medical College, Xuzhou, Jiangsu; Department of Hematology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu

Constitutive NF-κB activation is required for survival of activated B cell-like subtype of diffuse large B cell lymphoma (ABC-DLBCL). However, current NF-κB targeting strategies lack cancer cell specificity. Here, we identified a novel inhibitor, piperlongumine, features direct binding to NF-κB p65 subunit and suppression of p65 nuclear import. This was accompanied by NF-κB reporter activity suppression and NF-κB target gene downregulation. Moreover, mutation of Cys{sup 38} to Ser in p65 abolished this effect of piperlongumine on inhibition of p65 nuclear import. Furthermore, we show that piperlongumine selectively inhibited proliferation and induced apoptosis of ABC-DLBCL cells. Most notably, it has beenmore » reported that piperlongumine did not affect normal cells even at high doses and was nontoxic to animals. Hence, our current study provides new insight into piperlongumine's mechanism of action and novel approach to ABC-DLBCL target therapy. - Highlights: • Current NF-κB targeting strategies lack cancer cell specificity. • Piperlongumine inhibits NF-κB p65 subunit nuclear import via directly binding to p65. • Piperlongumine selectively inhibits proliferation of ABC-DLBCL cells. • This study provides a novel approach to ABC-DLBCL target therapy.« less

Identification of drug-resistant subpopulations in canine hemangiosarcoma.

PubMed

Khammanivong, A; Gorden, B H; Frantz, A M; Graef, A J; Dickerson, E B

2016-09-01

Canine hemangiosarcoma is a rapidly progressive disease that is poorly responsive to conventional chemotherapy. Despite numerous attempts to advance treatment options and improve outcomes, drug resistance remains a hurdle to successful therapy. To address this problem, we used recently characterized progenitor cell populations derived from canine hemangiosarcoma cell lines and grown as non-adherent spheres to identify potential drug resistance mechanisms as well as drug-resistant cell populations. Cells from sphere-forming cultures displayed enhanced resistance to chemotherapy drugs, expansion of dye-excluding side populations and altered ATP-binding cassette (ABC) transporter expression. Invasion studies demonstrated variability between cell lines as well as between sphere and monolayer cell populations. Collectively, our results suggest that sphere cell populations contain distinct subpopulations of drug-resistant cells that utilize multiple mechanisms to evade cytotoxic drugs. Our approach represents a new tool for the study of drug resistance in hemangiosarcoma, which could alter approaches for treating this disease. © 2014 John Wiley & Sons Ltd.

Variables affecting the quantitation of CD22 in neoplastic B cells.

PubMed

Jasper, Gregory A; Arun, Indu; Venzon, David; Kreitman, Robert J; Wayne, Alan S; Yuan, Constance M; Marti, Gerald E; Stetler-Stevenson, Maryalice

2011-03-01

Quantitative flow cytometry (QFCM) is being applied in the clinical flow cytometry laboratory for diagnosis, prognosis, and assessment of patients receiving antibody-based therapy. ABC values and the effect of technical variables on CD22 quantitation in acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), follicular lymphoma (FCL), hairy cell leukemia (HCL) and normal B cells were studied. The QuantiBrite System® was used to determine the level of CD22 expression (mean antibody bound per cell, ABC) by malignant and normal B cells. The intra-assay variability, number of cells required for precision, effect of delayed processing as well as shipment of peripheral blood specimens (delayed processing and exposure to noncontrolled environments), and the effect of paraformaldehyde fixation on assay results were studied. The QuantiBRITE method of measuring CD22 ABC is precise (median CV 1.6%, 95% confidence interval, 1.2-2.3%) but a threshold of 250 malignant cells is required for reliable CD22 ABC values. Delayed processing and overnight shipment of specimens resulted in significantly different ABC values whereas fixation for up to 12 h had no significant effect. ABC measurements determined that CD22 expression is lower than normal in ALL, CLL, FCL, and MCL but higher than normal in HCL. CD22 expression was atypical in the hematolymphoid malignancies studied and may have diagnostic utility. Technical variables such as cell number analyzed and delayed processing or overnight shipment of specimens impact significantly on the measurement of antigen expression by QFCM in the clinical laboratory. Published 2010 Wiley-Liss, Inc.

The mitochondrial transporter ABC-me (ABCB10), a downstream target of GATA-1, is essential for erythropoiesis in vivo

PubMed Central

Hyde, B B; Liesa, M; Elorza, A A; Qiu, W; Haigh, S E; Richey, L; Mikkola, H K; Schlaeger, T M; Shirihai, O S

2012-01-01

The mitochondrial transporter ATP binding cassette mitochondrial erythroid (ABC-me/ABCB10) is highly induced during erythroid differentiation by GATA-1 and its overexpression increases hemoglobin production rates in vitro. However, the role of ABC-me in erythropoiesis in vivo is unknown. Here we report for the first time that erythrocyte development in mice requires ABC-me. ABC-me−/− mice die at day 12.5 of gestation, showing nearly complete eradication of primitive erythropoiesis and lack of hemoglobinized cells at day 10.5. ABC-me−/− erythroid cells fail to differentiate because they exhibit a marked increase in apoptosis, both in vivo and ex vivo. Erythroid precursors are particularly sensitive to oxidative stress and ABC-me in the heart and its yeast ortholog multidrug resistance-like 1 have been shown to protect against oxidative stress. Thus, we hypothesized that increased apoptosis in ABC-me−/− erythroid precursors was caused by oxidative stress. Within this context, ABC-me deletion causes an increase in mitochondrial superoxide production and protein carbonylation in erythroid precursors. Furthermore, treatment of ABC-me−/− erythroid progenitors with the mitochondrial antioxidant MnTBAP (superoxide dismutase 2 mimetic) supports survival, ex vivo differentiation and increased hemoglobin production. Altogether, our findings demonstrate that ABC-me is essential for erythropoiesis in vivo. PMID:22240895

Profiling of ABC transporters ABCB5, ABCF2 and nestin-positive stem cells in nevi, in situ and invasive melanoma.

PubMed

Setia, Namrata; Abbas, Ossama; Sousa, Yessica; Garb, Jane L; Mahalingam, Meera

2012-08-01

Distinct ABCB5 forms and ABCF2, members of the ATP-binding cassette (ABC) superfamily of transporters, are normally expressed in various tissues and cells, and enhanced expression of both has been demonstrated in select cancers. In melanoma cell lines, gene expression profiling of ABC transporters has revealed enhanced expression of melanocyte-specific ABCB5 and ABCF2 proteins. Given this, our primary aim was to ascertain immunohistochemical expression of the ABC transporters ABCB5 and ABCF2 and, the stem cell marker, nestin in a spectrum of benign and malignant nevomelanocytic proliferations, including nevi (n=30), in situ (n=31) and invasive (n=24) primary cutaneous melanomas to assess their role in the stepwise development of malignancy. In addition, their expression was compared with established melanoma prognosticators to ascertain their utility as independent prognosticators. A semiquantitative scoring system was utilized by deriving a cumulative score (based on percentage positivity cells and intensity of expression) and statistical analyses was carried out using analysis of variance with linear contrasts. Mean cumulative score in nevi, in situ and invasive melanoma were as follows: 3.8, 4.4 and 5.3 for ABCB5, respectively (P<0.005 for all), and 4.6, 4.6 and 5.3 for nestin, respectively (P=not significant for all). No appreciable expression of ABCF2 was noted in any of the groups. While ulcerated lesions of melanoma demonstrated lower levels of expression of ABCB5 and nestin than non-ulcerated lesions, and nestin expression was lower in lesions with mitoses >1, after controlling for the presence of ulceration and mitotic activity, the expression of both proteins did not significantly correlate with known melanoma prognosticators. The gradual increase in the expression of ABCB5 from benign nevus to in situ to invasive melanoma suggests that it plays a role in melanomagenesis. On the basis of our findings, a prospective study with follow-up data is required to ascertain the utility of ABCB5 as a therapeutic target.

ABCE1 Is a Highly Conserved RNA Silencing Suppressor

PubMed Central

Kärblane, Kairi; Gerassimenko, Jelena; Nigul, Lenne; Piirsoo, Alla; Smialowska, Agata; Vinkel, Kadri; Kylsten, Per; Ekwall, Karl; Swoboda, Peter; Truve, Erkki; Sarmiento, Cecilia

2015-01-01

ATP-binding cassette sub-family E member 1 (ABCE1) is a highly conserved protein among eukaryotes and archaea. Recent studies have identified ABCE1 as a ribosome-recycling factor important for translation termination in mammalian cells, yeast and also archaea. Here we report another conserved function of ABCE1. We have previously described AtRLI2, the homolog of ABCE1 in the plant Arabidopsis thaliana, as an endogenous suppressor of RNA silencing. In this study we show that this function is conserved: human ABCE1 is able to suppress RNA silencing in Nicotiana benthamiana plants, in mammalian HEK293 cells and in the worm Caenorhabditis elegans. Using co-immunoprecipitation and mass spectrometry, we found a number of potential ABCE1-interacting proteins that might support its function as an endogenous suppressor of RNA interference. The interactor candidates are associated with epigenetic regulation, transcription, RNA processing and mRNA surveillance. In addition, one of the identified proteins is translin, which together with its binding partner TRAX supports RNA interference. PMID:25659154

Salinomycin overcomes ABC transporter-mediated multidrug and apoptosis resistance in human leukemia stem cell-like KG-1a cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuchs, Dominik; Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg; Daniel, Volker

2010-04-16

Leukemia stem cells are known to exhibit multidrug resistance by expression of ATP-binding cassette (ABC) transporters which constitute transmembrane proteins capable of exporting a wide variety of chemotherapeutic drugs from the cytosol. We show here that human promyeloblastic leukemia KG-1a cells exposed to the histone deacetylase inhibitor phenylbutyrate resemble many characteristics of leukemia stem cells, including expression of functional ABC transporters such as P-glycoprotein, BCRP and MRP8. Consequently, KG-1a cells display resistance to the induction of apoptosis by various chemotherapeutic drugs. Resistance to apoptosis induction by chemotherapeutic drugs can be reversed by cyclosporine A, which effectively inhibits the activity ofmore » P-glycoprotein and BCRP, thus demonstrating ABC transporter-mediated drug resistance in KG-1a cells. However, KG-1a are highly sensitive to apoptosis induction by salinomycin, a polyether ionophore antibiotic that has recently been shown to kill human breast cancer stem cell-like cells and to induce apoptosis in human cancer cells displaying multiple mechanisms of drug and apoptosis resistance. Whereas KG-1a cells can be adapted to proliferate in the presence of apoptosis-inducing concentrations of bortezomib and doxorubicin, salinomycin does not permit long-term adaptation of the cells to apoptosis-inducing concentrations. Thus, salinomycin should be regarded as a novel and effective agent for the elimination of leukemia stem cells and other tumor cells exhibiting ABC transporter-mediated multidrug resistance.« less

Aggressive aneurysmal bone cyst of the maxilla confused with telangiectatic osteosarcoma.

PubMed

Lee, Hyun-Min; Cho, Kyu-Sup; Choi, Kyung-Un; Roh, Hwan-Jung

2012-06-01

Aneurysmal bone cyst (ABC) is a benign, expansile lesion typically affecting the long bones and vertebrae of patients younger than 20 years. Approximately 2% of ABCs occur in the head and neck region, most commonly affecting the mandible. Although the most common co-existing lesion associated with ABCs is the giant cell tumor, ABCs can be radiologically confused with telangiectatic osteosarcoma in cases of aggressive behavior and rapid growth. Here, we report a case of an aggressive ABC of the maxilla confused with telangiectatic osteosarcoma in a patient who underwent several operations for an osteoblastoma that was diagnosed histopathologically. This case highlights the need for a differential diagnosis both radiologically and histopathologically, because ABCs can easily be interpreted as a giant cell tumor or an osteoblastoma, and, on occasion, can be mistaken for osteogenic malignancies. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

[The ABC transporters of Saccharomyces cerevisiae].

PubMed

Wawrzycka, Donata

2011-01-01

The ABC transporters (ATP Binding Cassette) compose one of the bigest protein family with the great medical, industrial and economical impact. They are found in all organism from bacteria to man. ABC proteins are responsible for resistance of microorganism to antibiotics and fungicides and multidrug resistance of cancer cells. Mutations in ABC transporters genes cause seriuos deseases like cystic fibrosis, adrenoleucodystrophy or ataxia. Transport catalized by ABC proteins is charged with energy from the ATP hydrolysis. The ABC superfamily contains transporters, canals, receptors. Analysis of the Saccharomyces cerevisiae genome allowed to distinguish 30 potential ABC proteins which are classified into 6 subfamilies. The structural and functional similarity of the yeast and human ABC proteins allowes to use the S. cerevisiae as a model organism for ABC transporters characterisation. In this work the present state of knowleadge on yeast S. cerevisiae ABC proteins was summarised.

Combinatorial BTK and MALT1 inhibition augments killing of CD79 mutant diffuse large B cell lymphoma

PubMed Central

Nagel, Daniel; Bognar, Miriam; Eitelhuber, Andrea C.; Kutzner, Kerstin; Vincendeau, Michelle; Krappmann, Daniel

2015-01-01

Survival of activated B cell-subtype (ABC) of diffuse large B cell lymphoma (DLBCL) is driven by chronic B cell receptor (BCR) signaling that activates the canonical NF-κB pathway. Inhibition of BTK by Ibrutinib has been shown to kill ABC DLBCL cells that carry activating mutations in the BCR adaptor CD79. However, mutations in BTK or in downstream components such as CARMA1/CARD11 can render lymphomas Ibrutinib resistant. Therefore, we assessed here the simultaneous inhibition of BTK and the protease MALT1 that acts downstream of CARMA1 and is essential for ABC DLBCL tumor growth. We show that in CD79 mutant cells BTK is a crucial upstream regulator of MALT1, but dispensable in CARMA1 mutant ABC DLBCL. Combined inhibition of BTK by Ibrutinib and MALT1 by S-Mepazine additively impaired MALT1 cleavage activity and expression of NF-κB pro-survival factors. Thereby, combinatorial Ibrutinib and S-Mepazine treatment enhanced killing of CD79 mutant ABC DLBCL cells. Moreover, while expression of oncogenic CARMA1 in CD79 mutant cells conferred Ibrutinib resistance, double mutant cells were still sensitive to MALT1 inhibition by S-Mepazine. Thus, based on the genetic background combinatorial BTK and MALT1 inhibition may improve effectiveness of therapeutic treatment and reduce the chances for the development of drug resistances. PMID:26540570

Suppression of c-Myc is involved in multi-walled carbon nanotubes' down-regulation of ATP-binding cassette transporters in human colon adenocarcinoma cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhaojing; Xu, Yonghong; Meng, Xiangning

Over-expression of ATP-binding cassette (ABC) transporters, a large family of integral membrane proteins that decrease cellular drug uptake and accumulation by active extrusion, is one of the major causes of cancer multi-drug resistance (MDR) that frequently leads to failure of chemotherapy. Carbon nanotubes (CNTs)-based drug delivery devices hold great promise in enhancing the efficacy of cancer chemotherapy. However, CNTs' effects on the ABC transporters remain under-investigated. In this study, we found that multiwalled carbon nanotubes (MWCNTs) reduced transport activity and expression of ABC transporters including ABCB1/Pgp and ABCC4/MRP4 in human colon adenocarcinoma Caco-2 cells. Proto-oncogene c-Myc, which directly regulates ABCmore » gene expression, was concurrently decreased in MWCNT-treated cells and forced over-expression of c-Myc reversed MWCNTs' inhibitory effects on ABCB1 and ABCC4 expression. MWCNT-cell membrane interaction and cell membrane oxidative damage were observed. However, antioxidants such as vitamin C, β-mecaptoethanol and dimethylthiourea failed to antagonize MWCNTs' down-regulation of ABC transporters. These data suggest that MWCNTs may act on c-Myc, but not through oxidative stress, to down-regulate ABC transporter expression. Our findings thus shed light on CNTs' novel cellular effects that may be utilized to develop CNTs-based drug delivery devices to overcome ABC transporter-mediated cancer chemoresistance.« less

RECEPTORS ON IMMUNOCOMPETENT CELLS

PubMed Central

Davie, Joseph M.; Paul, William E.

1971-01-01

Nonimmunized guinea pigs possess rare lymphocytes which bind sufficient 2,4-dinitrophenyl-guinea pig albumin-125I (DNP-GPA) to their surface to be detected by short-term radioautography. The cells occur in the lymph nodes, spleen, peripheral blood, and bone marrow with a frequency of ∼40/100,000 lymphocytes, but are absent from the thymus. The receptors of these cells are largely specific for the haptenic group (ε-DNP-L-lysine) as shown by inhibition of DNP-GPA-125I binding with ε-DNP-L-lysine and with DNP bovine serum albumin (DNP-BSA). Furthermore, these cells specifically adsorb to agarose beads to which either DNP-GPA, DNP-BSA, or DNP-keyhole limpet hemocyanin (KLH) has been covalently linked. This hapten specific depletion of DNP-GPA-125I antigen-binding cells (ABC) correlates with a similar diminution in the capacity of adsorbed populations to transfer primary responsiveness to DNP-KLH to irradiated syngeneic recipients. Fluoresceinated anti-immunoglobulin binds to the surface of some guinea pig lymphocytes, and all DNP-GPA-125I ABC, as shown by a double-label technique. The great majority of DNP-GPA ABC and human γ-globulin ABC possess surface Ig molecules of the γ2 heavy chain class. Preincubation of cell suspensions with anti-γ2 antibody markedly diminishes the number of DNP-GPA-125I ABC which are detected, strongly suggesting that the receptors of these cells are immunoglobulin molecules, most of which possess γ2 heavy chains. The specificity characteristics of DNP-GPA-125I ABC are strikingly different from those of cells mediating a cellular immune response to DNP-GPA, indicating major differences in the specificity and nature of the receptors of these cell types. PMID:4934503

Use of novel chitosan hydrogels for chemical tissue bonding of autologous chondral transplants.

PubMed

Gittens, Jamila; Haleem, Amgad M; Grenier, Stephanie; Smyth, Niall A; Hannon, Charles P; Ross, Keir A; Torzilli, Peter A; Kennedy, John G

2016-07-01

The objective of this study was to evaluate the effect of chemical tissue bonding (CTB) on adhesion strength, fluid permeability, and cell viability across a cartilaginous graft-host interface in an in vitro autologous chondral transplant (ACT) model. Chitosan-based cross-linkers; Chitosan-Rose Bengal [Chi-RB (Ch-ABC)], Chitosan-Genipin [Chi-GP (Ch-ABC)], and Chitosan-Rose Bengal-Genipin [Chi-RB-GP (Ch-ABC)] were applied to bovine immature cartilage explants after pre-treatment with surface degrading enzyme, Chondroitinase-ABC (Ch-ABC). Adhesion strength, fluid permeability and cell viability were assessed via mechanical push-out shear testing, fluid transport and live/dead cell staining, respectively. All three chitosan-based cross-linkers significantly increased the adhesion strength at the graft-host interface, however, only a statistically significant decrease in fluid permeability was noted in Chi-GP (Ch-ABC) specimen compared to untreated controls. Cell viability was maintained for 7 days of culture across all three treatment groups. These results show the potential clinical relevance of novel chitosan-based hydrogels in enhancing tissue integration and reducing synovial fluid penetration after ACT procedures in diarthoidal joints such as the knee and ankle. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1139-1146, 2016. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Role for chondroitin sulfate glycosaminoglycan in NEDD9-mediated breast cancer cell growth.

PubMed

Iida, Joji; Dorchak, Jesse; Clancy, Rebecca; Slavik, Juliana; Ellsworth, Rachel; Katagiri, Yasuhiro; Pugacheva, Elena N; van Kuppevelt, Toin H; Mural, Richard J; Cutler, Mary Lou; Shriver, Craig D

2015-01-15

There are lines of evidence demonstrating that NEDD9 (Cas-L, HEF-1) plays a key role in the development, progression, and metastasis of breast cancer cells. We previously reported that NEDD9 plays a critical role for promoting migration and growth of MDA-MB-231. In order to further characterize the mechanisms of NEDD9-mediated cancer migration and growth, stable cells overexpressing NEDD9 were generated using HCC38 as a parental cell line which expresses low level of endogenous NEDD9. Microarray studies demonstrated that core proteins of CD44 and Serglycin were markedly upregulated in HCC38(NEDD9) cells compared to HCC38(Vector) cells, while those of Syndecan-1, Syndecan-2, and Versican were downregulated in HCC38(NEDD9). Importantly, enzymes generating chondroitin sulfate glycosaminoglycans (CS) such as CHST11, CHST15, and CSGALNACT1 were upregulated in HCC38(NEDD9) compared to HCC38(Vector). Immunofluorescence studies using specific antibody, GD3G7, confirmed the enhanced expression of CS-E subunit in HCC38(NEDD9). Immunoprecipitation and western blotting analysis demonstrated that CS-E was attached to CD44 core protein. We demonstrated that removing CS by chondroitinase ABC significantly inhibited anchorage-independent colony formation of HCC38(NEDD9) in methylcellulose. Importantly, the fact that GD3G7 significantly inhibited colony formation of HCC38(NEDD9) cells suggests that CS-E subunit plays a key role in this process. Furthermore, treatment of HCC38(NEDD9) cells with chondroitinase ABC or GD3G7 significantly inhibited mammosphere formation. Exogenous addition of CS-E enhanced colony formation and mammosphere formation of HCC38 parental and HCC38(Vector) cells. These results suggest that NEDD9 regulates the synthesis and expression of tumor associated glycocalyx structures including CS-E, which plays a key role in promoting and regulating breast cancer progression and metastasis and possibly stem cell phenotypes. Copyright © 2014 Elsevier Inc. All rights reserved.

Transcription of putative tonoplast transporters in response to glyphosate and paraquat stress in Conyza bonariensis and Conyza canadensis and selection of reference genes for qRT-PCR.

PubMed

Moretti, Marcelo L; Alárcon-Reverte, Rocio; Pearce, Stephen; Morran, Sarah; Hanson, Bradley D

2017-01-01

Herbicide resistance is a challenge for modern agriculture further complicated by cases of resistance to multiple herbicides. Conyza bonariensis and Conyza canadensis are invasive weeds of field crops, orchards, and non-cropped areas in many parts of the world. In California, USA, Conyza populations resistant to the herbicides glyphosate and paraquat have recently been described. Although the mechanism conferring resistance to glyphosate and paraquat in these species was not elucidated, reduced translocation of these herbicides was observed under experimental conditions in both species. Glyphosate and paraquat resistance associated with reduced translocation are hypothesized to be a result of sequestration of herbicides into the vacuole, with the possible involvement of over-expression of genes encoding tonoplast transporters of ABC-transporter families in cases of glyphosate resistance or cationic amino acid transporters (CAT) in cases of paraquat resistance. However, gene expression in response to herbicide treatment has not been studied in glyphosate and paraquat resistant populations. In the current study, we evaluated the transcript levels of genes possibly involved in resistance using real-time PCR. First, we evaluated eight candidate reference genes following herbicide treatment and selected three genes that exhibited stable expression profiles; ACTIN, HEAT-SHOCK-PROTEIN-70, and CYCLOPHILIN. The reference genes identified here can be used for further studies related to plant-herbicide interactions. We used these reference genes to assay the transcript levels of EPSPS, ABC transporters, and CAT in response to herbicide treatment in susceptible and resistant Conyza spp. lines. No transcription changes were observed in EPSPS or CAT genes after glyphosate or paraquat treatment, suggesting that these genes are not involved in the resistance mechanism. Transcription of the two ABC transporter genes increased following glyphosate treatment in all Conyza spp. lines. Transcription of ABC transporters also increased after paraquat treatment in all three lines of C. bonariensis. However, in C. canadensis, paraquat treatment increased transcription of only one ABC transporter gene in the susceptible line. The increase in transcription of ABC transporters after herbicide treatment is likely a stress response based on similar response observed across all Conyza lines regardless of resistance or sensitivity to glyphosate or paraquat, thus these genes do not appear to be directly involved in the mechanism of resistance in Conyza spp.

Transcription of putative tonoplast transporters in response to glyphosate and paraquat stress in Conyza bonariensis and Conyza canadensis and selection of reference genes for qRT-PCR

PubMed Central

Alárcon-Reverte, Rocio; Pearce, Stephen; Morran, Sarah; Hanson, Bradley D.

2017-01-01

Herbicide resistance is a challenge for modern agriculture further complicated by cases of resistance to multiple herbicides. Conyza bonariensis and Conyza canadensis are invasive weeds of field crops, orchards, and non-cropped areas in many parts of the world. In California, USA, Conyza populations resistant to the herbicides glyphosate and paraquat have recently been described. Although the mechanism conferring resistance to glyphosate and paraquat in these species was not elucidated, reduced translocation of these herbicides was observed under experimental conditions in both species. Glyphosate and paraquat resistance associated with reduced translocation are hypothesized to be a result of sequestration of herbicides into the vacuole, with the possible involvement of over-expression of genes encoding tonoplast transporters of ABC-transporter families in cases of glyphosate resistance or cationic amino acid transporters (CAT) in cases of paraquat resistance. However, gene expression in response to herbicide treatment has not been studied in glyphosate and paraquat resistant populations. In the current study, we evaluated the transcript levels of genes possibly involved in resistance using real-time PCR. First, we evaluated eight candidate reference genes following herbicide treatment and selected three genes that exhibited stable expression profiles; ACTIN, HEAT-SHOCK-PROTEIN-70, and CYCLOPHILIN. The reference genes identified here can be used for further studies related to plant-herbicide interactions. We used these reference genes to assay the transcript levels of EPSPS, ABC transporters, and CAT in response to herbicide treatment in susceptible and resistant Conyza spp. lines. No transcription changes were observed in EPSPS or CAT genes after glyphosate or paraquat treatment, suggesting that these genes are not involved in the resistance mechanism. Transcription of the two ABC transporter genes increased following glyphosate treatment in all Conyza spp. lines. Transcription of ABC transporters also increased after paraquat treatment in all three lines of C. bonariensis. However, in C. canadensis, paraquat treatment increased transcription of only one ABC transporter gene in the susceptible line. The increase in transcription of ABC transporters after herbicide treatment is likely a stress response based on similar response observed across all Conyza lines regardless of resistance or sensitivity to glyphosate or paraquat, thus these genes do not appear to be directly involved in the mechanism of resistance in Conyza spp. PMID:28700644

Factors associated with prolonged time to treatment failure with fulvestrant 500 mg in patients with post-menopausal estrogen receptor-positive advanced breast cancer: a sub-group analysis of the JBCRG-C06 Safari study.

PubMed

Kawaguchi, Hidetoshi; Masuda, Norikazu; Nakayama, Takahiro; Aogi, Kenjiro; Anan, Keisei; Ito, Yoshinori; Ohtani, Shoichiro; Sato, Nobuaki; Saji, Shigehira; Takano, Toshimi; Tokunaga, Eriko; Nakamura, Seigo; Hasegawa, Yoshie; Hattori, Masaya; Fujisawa, Tomomi; Morita, Satoshi; Yamaguchi, Miki; Yamashita, Hiroko; Yamashita, Toshinari; Yamamoto, Yutaka; Yotsumoto, Daisuke; Toi, Masakazu; Ohno, Shinji

2018-01-01

The JBCRG-C06 Safari study showed that earlier fulvestrant 500 mg (F500) use, a longer time from diagnosis to F500 use, and no prior palliative chemotherapy were associated with significantly longer time to treatment failure (TTF) among Japanese patients with estrogen receptor-positive (ER+) advanced breast cancer (ABC). The objective of this sub-group analysis was to further examine data from the Safari study, focusing on ER + and human epidermal growth factor receptor-negative (HER2-) cases. The Safari study (UMIN000015168) was a retrospective, multi-center cohort study, conducted in 1,072 patients in Japan taking F500 for ER + ABC. The sub-analysis included only patients administered F500 as second-line or later therapy (n = 960). Of these, 828 patients were HER2-. Results Multivariate analysis showed that advanced age (≥65 years; p = .035), longer time (≥3 years) from ABC diagnosis to F500 use (p < .001), no prior chemotherapy (p < .001), and F500 treatment line (p < .001) were correlated with prolonged TTF (median = 5.39 months). In ER+/HER2- patients receiving F500 as a second-line or later therapy, treatment line, advanced age, no prior palliative chemotherapy use, and a longer period from ABC diagnosis to F500 use were associated with longer TTF.

Harnessing Drug Resistance: Using ABC Transporter Proteins To Target Cancer Cells

PubMed Central

Leitner, Heather M.; Kachadourian, Remy; Day, Brian J.

2007-01-01

The ATP-binding cassette (ABC) class of proteins is one of the most functionally diverse transporter families found in biological systems. Although the abundance of ABC proteins varies between species, they are highly conserved in sequence and often demonstrate similar functions across prokaryotic and eukaryotic organisms. Beginning with a brief summary of the events leading to our present day knowledge of ABC transporters, the purpose of this review is to discuss the potential for utilizing ABC transporters as a means for cellular glutathione (GSH) modulation. GSH is one of the most abundant thiol antioxidants in cells. It is involved in cellular division, protein and DNA synthesis, maintenance of cellular redox status and xenobiotic metabolism. Cellular GSH levels are often altered in many disease states including cancer. Over the past two decades there has been considerable emphasis on methods to sensitize cancer cells to chemotherapeutics and ionization radiation therapy by GSH depletion. We contend that ABC transporters, particularly multi-drug resistant proteins (MRPs), may be used as therapeutic targets for applications aimed at modulation of GSH levels. This review will emphasize MRP-mediated modulation of intracellular GSH levels as a potential alternative and adjunctive approach for cancer therapy. PMID:17585883

Characterization and regulation of the resistance-nodulation-cell division-type multidrug efflux pumps MdtABC and MdtUVW from the fire blight pathogen Erwinia amylovora.

PubMed

Pletzer, Daniel; Weingart, Helge

2014-07-11

The Gram-negative bacterium Erwinia amylovora is the causal agent of the devastating disease fire blight in rosaceous plants such as apple, pear, quince, raspberry, and cotoneaster. In order to survive and multiply in a host, microbes must be able to circumvent the toxic effects of antimicrobial plant compounds, such as flavonoids and tannins. E. amylovora uses multidrug efflux transporters that recognize and actively export toxic compounds out of the cells. Here, two heterotrimeric resistance-nodulation-cell division (RND)-type multidrug efflux pumps, MdtABC and MdtUVW, from E. amylovora were identified. These RND systems are unusual in that they contain two different RND proteins forming a functional pump. To find the substrate specificities of the two efflux systems, we overexpressed the transporters in a hypersensitive mutant lacking the major RND pump AcrB. Both transporters mediated resistance to several flavonoids, fusidic acid and novobiocin. Additionally, MdtABC mediated resistance towards josamycin, bile salts and silver nitrate, and MdtUVW towards clotrimazole. The ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock was reduced. Quantitative RT-PCR analyses revealed that the expression of the transporter genes was induced during infection of apple rootstock. The polyphenolic plant compound tannin, as well as the heavy metal salt tungstate was found to induce the expression of mdtABC. Finally, the expression of the mdtABC genes was shown to be regulated by BaeR, the response regulator of the two-component system BaeSR, a cell envelope stress response system that controls the adaptive responses to changes in the environment. The expression of MdtABC and MdtUVW is induced during growth of E. amylovora in planta. We identified the plant polyphenol tannin as inducer of mdtABC expression. The reduced ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock suggests that the efflux pumps are involved in resistance to plant antimicrobials, maybe including flavonoids, which were identified as substrates of both pumps. Furthermore, we found that the mdtABC operon belongs to the regulon of the two-component regulator BaeR suggesting a role of this RND transporter in the cell envelope stress response of E. amylovora.

Characterization and regulation of the Resistance-Nodulation-Cell Division-type multidrug efflux pumps MdtABC and MdtUVW from the fire blight pathogen Erwinia amylovora

PubMed Central

2014-01-01

Background The Gram-negative bacterium Erwinia amylovora is the causal agent of the devastating disease fire blight in rosaceous plants such as apple, pear, quince, raspberry, and cotoneaster. In order to survive and multiply in a host, microbes must be able to circumvent the toxic effects of antimicrobial plant compounds, such as flavonoids and tannins. E. amylovora uses multidrug efflux transporters that recognize and actively export toxic compounds out of the cells. Here, two heterotrimeric resistance-nodulation-cell division (RND)-type multidrug efflux pumps, MdtABC and MdtUVW, from E. amylovora were identified. These RND systems are unusual in that they contain two different RND proteins forming a functional pump. Results To find the substrate specificities of the two efflux systems, we overexpressed the transporters in a hypersensitive mutant lacking the major RND pump AcrB. Both transporters mediated resistance to several flavonoids, fusidic acid and novobiocin. Additionally, MdtABC mediated resistance towards josamycin, bile salts and silver nitrate, and MdtUVW towards clotrimazole. The ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock was reduced. Quantitative RT-PCR analyses revealed that the expression of the transporter genes was induced during infection of apple rootstock. The polyphenolic plant compound tannin, as well as the heavy metal salt tungstate was found to induce the expression of mdtABC. Finally, the expression of the mdtABC genes was shown to be regulated by BaeR, the response regulator of the two-component system BaeSR, a cell envelope stress response system that controls the adaptive responses to changes in the environment. Conclusions The expression of MdtABC and MdtUVW is induced during growth of E. amylovora in planta. We identified the plant polyphenol tannin as inducer of mdtABC expression. The reduced ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock suggests that the efflux pumps are involved in resistance to plant antimicrobials, maybe including flavonoids, which were identified as substrates of both pumps. Furthermore, we found that the mdtABC operon belongs to the regulon of the two-component regulator BaeR suggesting a role of this RND transporter in the cell envelope stress response of E. amylovora. PMID:25012600

Osimertinib (AZD9291), a Mutant-Selective EGFR Inhibitor, Reverses ABCB1-Mediated Drug Resistance in Cancer Cells.

PubMed

Zhang, Xiao-Yu; Zhang, Yun-Kai; Wang, Yi-Jun; Gupta, Pranav; Zeng, Leli; Xu, Megan; Wang, Xiu-Qi; Yang, Dong-Hua; Chen, Zhe-Sheng

2016-09-15

In recent years, tyrosine kinase inhibitors (TKIs) have been shown capable of inhibiting the ATP-binding cassette (ABC) transporter-mediated multidrug resistance (MDR). In this study, we determine whether osimertinib, a novel selective, irreversible EGFR (epidermal growth factor receptor) TKI, could reverse ABC transporter-mediated MDR. The results showed that, at non-toxic concentrations, osimertinib significantly sensitized both ABCB1-transfected and drug-selected cell lines to substrate anticancer drugs colchicine, paclitaxel, and vincristine. Osimertinib significantly increased the accumulation of [³H]-paclitaxel in ABCB1 overexpressing cells by blocking the efflux function of ABCB1 transporter. In contrast, no significant alteration in the expression levels and localization pattern of ABCB1 was observed when ABCB1 overexpressing cells were exposed to 0.3 µM osimertinib for 72 h. In addition, ATPase assay showed osimertinib stimulated ABCB1 ATPase activity. Molecular docking and molecular dynamic simulations showed osimertinib has strong and stable interactions at the transmembrane domain of human homology ABCB1. Taken together, our findings suggest that osimertinib, a clinically-approved third-generation EGFR TKI, can reverse ABCB1-mediated MDR, which supports the combination therapy with osimertinib and ABCB1 substrates may potentially be a novel therapeutic stategy in ABCB1-positive drug resistant cancers.

Sensitivity to PI3K and AKT inhibitors is mediated by divergent molecular mechanisms in subtypes of DLBCL.

PubMed

Erdmann, Tabea; Klener, Pavel; Lynch, James T; Grau, Michael; Vočková, Petra; Molinsky, Jan; Tuskova, Diana; Hudson, Kevin; Polanska, Urszula M; Grondine, Michael; Mayo, Michele; Dai, Beiying; Pfeifer, Matthias; Erdmann, Kristian; Schwammbach, Daniela; Zapukhlyak, Myroslav; Staiger, Annette M; Ott, German; Berdel, Wolfgang E; Davies, Barry R; Cruzalegui, Francisco; Trneny, Marek; Lenz, Peter; Barry, Simon T; Lenz, Georg

2017-07-20

Activated B-cell-like (ABC) and germinal center B-cell-like diffuse large B-cell lymphoma (DLBCL) represent the 2 major molecular DLBCL subtypes. They are characterized by differences in clinical course and by divergent addiction to oncogenic pathways. To determine activity of novel compounds in these 2 subtypes, we conducted an unbiased pharmacologic in vitro screen. The phosphatidylinositol-3-kinase (PI3K) α/δ (PI3Kα/δ) inhibitor AZD8835 showed marked potency in ABC DLBCL models, whereas the protein kinase B (AKT) inhibitor AZD5363 induced apoptosis in PTEN-deficient DLBCLs irrespective of their molecular subtype. These in vitro results were confirmed in various cell line xenograft and patient-derived xenograft mouse models in vivo. Treatment with AZD8835 induced inhibition of nuclear factor κB signaling, prompting us to combine AZD8835 with the Bruton's tyrosine kinase inhibitor ibrutinib. This combination was synergistic and effective both in vitro and in vivo. In contrast, the AKT inhibitor AZD5363 was effective in PTEN-deficient DLBCLs through downregulation of the oncogenic transcription factor MYC. Collectively, our data suggest that patients should be stratified according to their oncogenic dependencies when treated with PI3K and AKT inhibitors. © 2017 by The American Society of Hematology.

Characterization of acquired paclitaxel resistance of breast cancer cells and involvement of ABC transporters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Němcová-Fürstová, Vlasta, E-mail: vlasta.furstova@

Development of taxane resistance has become clinically very important issue. The molecular mechanisms underlying the resistance are still unclear. To address this issue, we established paclitaxel-resistant sublines of the SK-BR-3 and MCF-7 breast cancer cell lines that are capable of long-term proliferation in 100 nM and 300 nM paclitaxel, respectively. Application of these concentrations leads to cell death in the original counterpart cells. Both sublines are cross-resistant to doxorubicin, indicating the presence of the MDR phenotype. Interestingly, resistance in both paclitaxel-resistant sublines is circumvented by the second-generation taxane SB-T-1216. Moreover, we demonstrated that it was not possible to establish sublinesmore » of SK-BR-3 and MCF-7 cells resistant to this taxane. It means that at least the tested breast cancer cells are unable to develop resistance to some taxanes. Employing mRNA expression profiling of all known human ABC transporters and subsequent Western blot analysis of the expression of selected transporters, we demonstrated that only the ABCB1/PgP and ABCC3/MRP3 proteins were up-regulated in both paclitaxel-resistant sublines. We found up-regulation of ABCG2/BCRP and ABCC4 proteins only in paclitaxel-resistant SK-BR-3 cells. In paclitaxel-resistant MCF-7 cells, ABCB4/MDR3 and ABCC2/MRP2 proteins were up-regulated. Silencing of ABCB1 expression using specific siRNA increased significantly, but did not completely restore full sensitivity to both paclitaxel and doxorubicin. Thus we showed a key, but not exclusive, role for ABCB1 in mechanisms of paclitaxel resistance. It suggests the involvement of multiple mechanisms in paclitaxel resistance in tested breast cancer cells. - Highlights: • Expression of all ABC transporters in paclitaxel-resistant sublines of SK-BR-3 and MCF-7 cells was analyzed. • SK-BR-3 and MCF-7 cells are unable to develop resistance to some taxanes. • Some taxanes are able to overcome developed resistance to paclitaxel. • Paclitaxel resistance was associated with increased levels of ABCB1 and ABCC3 protein. • ABCB1 silencing increased significantly sensitivity to both paclitaxel and doxorubicin.« less

ABCF2, an Nrf2 target gene, contributes to cisplatin resistance in ovarian cancer cells.

PubMed

Bao, Lingjie; Wu, Jianfa; Dodson, Matthew; Rojo de la Vega, Elisa Montserrat; Ning, Yan; Zhang, Zhenbo; Yao, Ming; Zhang, Donna D; Xu, Congjian; Yi, Xiaofang

2017-06-01

Previously, we have demonstrated that NRF2 plays a key role in mediating cisplatin resistance in ovarian cancer. To further explore the mechanism underlying NRF2-dependent cisplatin resistance, we stably overexpressed or knocked down NRF2 in parental and cisplatin-resistant human ovarian cancer cells, respectively. These two pairs of stable cell lines were then subjected to microarray analysis, where we identified 18 putative NRF2 target genes. Among these genes, ABCF2, a cytosolic member of the ABC superfamily of transporters, has previously been reported to contribute to chemoresistance in clear cell ovarian cancer. A detailed analysis on ABCF2 revealed a functional antioxidant response element (ARE) in its promoter region, establishing ABCF2 as an NRF2 target gene. Next, we investigated the contribution of ABCF2 in NRF2-mediated cisplatin resistance using our stable ovarian cancer cell lines. The NRF2-overexpressing cell line, containing high levels of ABCF2, was more resistant to cisplatin-induced apoptosis compared to its control cell line; whereas the NRF2 knockdown cell line with low levels of ABCF2, was more sensitive to cisplatin treatment than its control cell line. Furthermore, transient overexpression of ABCF2 in the parental cells decreased apoptosis and increased cell viability following cisplatin treatment. Conversely, knockdown of ABCF2 using specific siRNA notably increased apoptosis and decreased cell viability in cisplatin-resistant cells treated with cisplatin. This data indicate that the novel NRF2 target gene, ABCF2, plays a critical role in cisplatin resistance in ovarian cancer, and that targeting ABCF2 may be a new strategy to improve chemotherapeutic efficiency. © 2017 Wiley Periodicals, Inc.

Bfr1p is responsible for tributyltin resistance in Schizosaccharomyces pombe.

PubMed

Akiyama, Koichi; Iwaki, Tomoko; Sugimoto, Naoko; Chardwiriyapreecha, Soracom; Kawano, Miyuki; Nishimoto, Sogo; Sugahara, Takuya; Sekito, Takayuki; Kakinuma, Yoshimi

2011-01-01

ATP-binding cassette (ABC) transporter plays an important role for resistance against xenobiotics. There are eleven ABC transporter genes in the genome of fission yeast Schizosaccharomyces pombe. We examined the role of ABC transporter against the toxicity of tributyltin chloride (TBT), a widespread environmental pollutant, in cell growth. Among individual ABC transporter mutants, the growth of a mutant deficient in Bfr1p, a plasma membrane-embedded transporter, was extremely sensitive to TBT. The lethal TBT concentration inducing 50% of cell death (LC(50)) was 25 µM for the parent strain and 10.2 µM for the bfr1∆ mutant. Thus, Bfr1p was responsible for TBT resistance in S. pombe.

The Role of ABC Proteins in Drug Resistant Breast Cancer Cells

DTIC Science & Technology

2008-04-01

are indicated. (B) Cartoon of the predicted PfMDR1 secondary structure indicating helices ( gray ), loops (lines), and Walker A (vertical stripes...GTC 6 22 2 18 11 GTG 11 20 5 2 13 GTT 41 41 31 13 5 6064 Biochemistry, Vol. 46, No. 20, 2007 Amoah et al. to vanadate (Figure 4E) but high sensitivity... gray vs black bars) as were inhibitory effects seen at high dose CQ (Figure 9C, solid bars). DISCUSSION Reproducible high level overexpression of

Diagnosing and discriminating between primary and secondary aneurysmal bone cysts

PubMed Central

Sasaki, Hiromi; Nagano, Satoshi; Shimada, Hirofumi; Yokouchi, Masahiro; Setoguchi, Takao; Ishidou, Yasuhiro; Kunigou, Osamu; Maehara, Kosuke; Komiya, Setsuro

2017-01-01

Aneurysmal bone cysts (ABCs) are benign bony lesions frequently accompanied by multiple cystic lesions and aggressive bone destruction. They are relatively rare lesions, representing only 1% of bone tumors. The pathogenesis of ABCs has yet to be elucidated. In the present study, a series of 22 cases of primary and secondary ABC from patients treated in Department of Orthopedic Surgery, Kagoshima University Hospital (Kagoshima, Japan) from 2001–2015 were retrospectively analyzed. The average age at the time of diagnosis of primary ABC was 17.9 years. Intralesional curettage and artificial bone grafting were performed in the majority of the patients with primary ABC. The local recurrence rate following curettage for primary ABC was 18%, and the cause of local recurrence was considered to be insufficient curettage. Although no adjuvant therapy was administered during the surgeries, it may assist the prevention of local recurrence in certain cases. The cases of secondary ABC were preceded by benign bone tumors, including fibrous dysplasia, giant cell tumors, chondroblastoma and non-ossifying fibroma. The features of the secondary ABC typically reflected those of the preceding bone tumor. In the majority of cases, distinguishing the primary ABC from the secondary ABC was possible based on characteristic features, including age of the patient at diagnosis and the tumor location. In cases that exhibit ambiguous features, including a soft tissue mass or a thick septal enhancement on the preoperative magnetic resonance images, a biopsy must be obtained in order to exclude other types of aggressive bone tumors, including giant cell tumor, osteosarcoma and telangiectatic osteosarcoma. PMID:28454393

An alternative physiological role for the EmhABC efflux pump in Pseudomonas fluorescens cLP6a

PubMed Central

2011-01-01

Background Efflux pumps belonging to the resistance-nodulation-division (RND) superfamily in bacteria are involved in antibiotic resistance and solvent tolerance but have an unknown physiological role. EmhABC, a RND-type efflux pump in Pseudomonas fluorescens strain cLP6a, extrudes hydrophobic antibiotics, dyes and polycyclic aromatic hydrocarbons including phenanthrene. The effects of physico-chemical factors such as temperature or antibiotics on the activity and expression of EmhABC were determined in order to deduce its physiological role(s) in strain cLP6a in comparison to the emhB disruptant strain, cLP6a-1. Results Efflux assays conducted with 14C-phenanthrene showed that EmhABC activity is affected by incubation temperature. Increased phenanthrene efflux was measured in cLP6a cells grown at 10°C and decreased efflux was observed at 35°C compared with cells grown at the optimum temperature of 28°C. Membrane fatty acids in cLP6a cells were substantially altered by changes in growth temperature and in the presence of tetracycline. Changed membrane fatty acids and increased membrane permeability were associated with ~30-fold increased expression of emhABC in cLP6a cells grown at 35°C, and with increased extracellular free fatty acids. Growth of P. fluorescens cLP6a at supra-optimal temperature was enhanced by the presence of EmhABC compared to strain cLP6a-1. Conclusions Combined, these observations suggest that the EmhABC efflux pump may be involved in the management of membrane stress effects such as those due to unfavourable incubation temperatures. Efflux of fatty acids replaced as a result of membrane damage or phospholipid turnover may be the primary physiological role of the EmhABC efflux pump in P. fluorescens cLP6a. PMID:22085438

ATP-binding cassette transporters in tumor endothelial cells and resistance to metronomic chemotherapy.

PubMed

Hida, Kyoko; Kikuchi, Hiroshi; Maishi, Nako; Hida, Yasuhiro

2017-08-01

Drug resistance is a major problem in anticancer therapy. ATP-binding cassette (ABC) transporters have a role in the multidrug resistance. A new regimen of chemotherapy has been proposed, called "metronomic chemotherapy". Metronomic chemotherapy is the frequent, regular administration of drug doses designed to maintain low, but active, concentrations of chemotherapeutic drugs over prolonged periods of time, without causing serious toxicities. Metronomic chemotherapy regimens were developed to optimize the antitumor efficacy of agents that target the tumor vasculature instead of tumor cells, and to reduce toxicity of antineoplastic drugs [1]. Nevertheless, recent studies revealed that ABC transporters are expressed at a higher level in the endothelium in the tumor. To avoid resistance to metronomic anti-angiogenic chemotherapy, ABC transporter inhibition of tumor endothelial cells may be a promising strategy. In this mini-review, we discuss the possible mechanism of resistance to metronomic chemotherapy from the viewpoint of tumor endothelial cell biology, focusing on ABC transporters. Copyright © 2017. Published by Elsevier B.V.

Investigation of the quaternary structure of an ABC transporter in living cells using spectrally resolved resonance energy transfer

NASA Astrophysics Data System (ADS)

Singh, Deo Raj

Forster resonance energy transfer (FRET) has become an important tool to study proteins inside living cells. It has been used to explore membrane protein folding and dynamics, determine stoichiometry and geometry of protein complexes, and measure the distance between two molecules. In this dissertation, we use a method based on FRET and optical micro-spectroscopy (OptiMiS) technology, developed in our lab, to probe the structure of dynamic (as opposed to static) protein complexes in living cells. We use this method to determine the association stoichiometry and quaternary structure of an ABC transporter in living cells. Specifically, the transporter we investigate originates from the pathogen Pseudomonas aeruginosa, which is a Gram-negative bacterium with several virulence factors, lipopolysaccharides being one of them. This pathogen coexpresses two unique forms of lipopolysaccharides on its surface, the A- and B-bands. The A-band polysaccharides, synthesized in the cytoplasm, are translocated into the periplasm through an ATP-binding-cassette (ABC) transporter consisting of a transmembranar protein, Wzm, and a nucleotide-binding protein, Wzt. In P. aeruginosa, all of the biochemical studies of A-band LPS are concentrated on the stages of the synthesis and ligation of polysaccharides (PSs), leaving the export stage involving ABC transporter unexplored. The mode of PS export through ABC transporters is still unknown. This difficulty is due to the lack of information about sub-unit composition and structure of this bi-component ABC transporter. Using the FRET-OptiMiS combination method developed by our lab, we found that Wzt forms a rhombus-shaped homo-tetramer which becomes a square upon co-expression with Wzm, and that Wzm forms a square-shaped homo-tetramer both in the presence and absence of Wzt. Based on these results, we propose a structural model for the double-tetramer complex formed by the bi-component ABC transporter in living cells. An understanding of the structure and behavior of this ABC transporter will help develop antibiotics targeting the biosynthesis of the A-band LPS endotoxin.

Regulation of Expression of abcA and Its Response to Environmental Conditions

PubMed Central

Villet, Regis A.; Truong-Bolduc, Que Chi; Wang, Yin; Estabrooks, Zoe; Medeiros, Heidi

2014-01-01

The ATP-dependent transporter gene abcA in Staphylococcus aureus confers resistance to hydrophobic β-lactams. In strain ISP794, abcA is regulated by the transcriptional regulators MgrA and NorG and shares a 420-nucleotide intercistronic region with the divergently transcribed pbp4 gene, which encodes the transpeptidase Pbp4. Exposure of exponentially growing cells to iron-limited media, oxidative stress, and acidic pH (5.5) for 0.5 to 2 h had no effect on abcA expression. In contrast, nutrient limitation produced a significant increase in abcA transcripts. We identified three additional regulators (SarA, SarZ, and Rot) that bind to the overlapping promoter region of abcA and pbp4 in strain MW2 and investigated their role in the regulation of abcA expression. Expression of abcA is decreased by 10.0-fold in vivo in a subcutaneous abscess model. In vitro, abcA expression depends on rot and sarZ regulators. Moenomycin A exposure of strain MW2 produced an increase in abcA transcripts. Relative to MW2, the MIC of moenomycin was decreased 8-fold for MW2ΔabcA and increased 10-fold for the MW2 abcA overexpresser, suggesting that moenomycin is a substrate of AbcA. PMID:24509312

MC70 potentiates doxorubicin efficacy in colon and breast cancer in vitro treatment.

PubMed

Azzariti, Amalia; Quatrale, Anna E; Porcelli, Letizia; Colabufo, Nicola A; Cantore, Mariangela; Cassano, Giuseppe; Gasparre, Giuseppe; Iannelli, Giuseppina; Tommasi, Stefania; Panaro, Maria A; Paradiso, Angelo

2011-11-16

A major limitation of cancer treatment is the ability of cancer cells to develop resistance to chemotherapeutic drugs, by the establishment of multidrug resistance. Here, we characterize MC70 as ABC transporters inhibitor and anticancer agent, alone or with chemotherapy. MC70 was analyzed for its interaction with ABCB1, ABCG2 and ABCC1 by specific transport assays. In breast and colon cancer cell lines, cell growth and apoptosis were measured by MTT assay and DNA laddering Elisa kit, respectively. Cell cycle perturbation and cellular targets modulation were analyzed by Flow-cytometry and Western blotting, respectively. MC70 interacted with ABC transporters. In breast cancer cells, MC70 slightly inhibited cell proliferation strongly enhancing doxorubicin effectiveness. By contrast, MC70 was found to inhibit cell growth in colon cancer cells without affecting doxorubicin efficacy and in combination with topoisomerase I inhibitors it could be a promising therapeutic approach. What is more, it was also observed that MC70 induced apoptosis, canceled in favor of necrosis when given in combination with high doses of doxorubicin. MC70 inhibited cell migration probably through its interaction with sigma-1 receptor. Modulations of i) cell cycle, ii) pAkt and the phosphorylation of the three MAPKs were highlighted, while any activity was excluded at transcription level, thus accounting for the phenotypic effects observed. MC70 might be considered as a new potential anticancer agent capable to i) enhance chemotherapy effectiveness and ii) to play a contributory role in the treatment of chemotherapy resistant tumors. Copyright © 2011 Elsevier B.V. All rights reserved.

Sensitive and Specific Fluorescent Probes for Functional Analysis of the Three Major Types of Mammalian ABC Transporters

PubMed Central

Lebedeva, Irina V.; Pande, Praveen; Patton, Wayne F.

2011-01-01

An underlying mechanism for multi drug resistance (MDR) is up-regulation of the transmembrane ATP-binding cassette (ABC) transporter proteins. ABC transporters also determine the general fate and effect of pharmaceutical agents in the body. The three major types of ABC transporters are MDR1 (P-gp, P-glycoprotein, ABCB1), MRP1/2 (ABCC1/2) and BCRP/MXR (ABCG2) proteins. Flow cytometry (FCM) allows determination of the functional expression levels of ABC transporters in live cells, but most dyes used as indicators (rhodamine 123, DiOC2(3), calcein-AM) have limited applicability as they do not detect all three major types of ABC transporters. Dyes with broad coverage (such as doxorubicin, daunorubicin and mitoxantrone) lack sensitivity due to overall dimness and thus may yield a significant percentage of false negative results. We describe two novel fluorescent probes that are substrates for all three common types of ABC transporters and can serve as indicators of MDR in flow cytometry assays using live cells. The probes exhibit fast internalization, favorable uptake/efflux kinetics and high sensitivity of MDR detection, as established by multidrug resistance activity factor (MAF) values and Kolmogorov-Smirnov statistical analysis. Used in combination with general or specific inhibitors of ABC transporters, both dyes readily identify functional efflux and are capable of detecting small levels of efflux as well as defining the type of multidrug resistance. The assay can be applied to the screening of putative modulators of ABC transporters, facilitating rapid, reproducible, specific and relatively simple functional detection of ABC transporter activity, and ready implementation on widely available instruments. PMID:21799851

Long-term drug modification to the surface of mesenchymal stem cells by the avidin-biotin complex method.

PubMed

Takayama, Yukiya; Kusamori, Kosuke; Hayashi, Mika; Tanabe, Noriko; Matsuura, Satoru; Tsujimura, Mari; Katsumi, Hidemasa; Sakane, Toshiyasu; Nishikawa, Makiya; Yamamoto, Akira

2017-12-05

Mesenchymal stem cells (MSCs) have various functions, making a significant contribution to tissue repair. On the other hand, the viability and function of MSCs are not lasting after an in vivo transplant, and the therapeutic effects of MSCs are limited. Although various chemical modification methods have been applied to MSCs to improve their viability and function, most of conventional drug modification methods are short-term and unstable and cause cytotoxicity. In this study, we developed a method for long-term drug modification to C3H10T1/2 cells, murine mesenchymal stem cells, without any damage, using the avidin-biotin complex method (ABC method). The modification of NanoLuc luciferase (Nluc), a reporter protein, to C3H10T1/2 cells by the ABC method lasted for at least 14 days in vitro without major effects on the cellular characteristics (cell viability, cell proliferation, migration ability, and differentiation ability). Moreover, in vivo, the surface Nluc modification to C3H10T1/2 cells by the ABC method lasted for at least 7 days. Therefore, these results indicate that the ABC method may be useful for long-term surface modification of drugs and for effective MSC-based therapy.

Inducing articular cartilage phenotype in costochondral cells

PubMed Central

2013-01-01

Introduction Costochondral cells may be isolated with minimal donor site morbidity and are unaffected by pathologies of the diarthrodial joints. Identification of optimal exogenous stimuli will allow abundant and robust hyaline articular cartilage to be formed from this cell source. Methods In a three factor, two level full factorial design, the effects of hydrostatic pressure (HP), transforming growth factor β1 (TGF-β1), and chondroitinase ABC (C-ABC), and all resulting combinations, were assessed in third passage expanded, redifferentiated costochondral cells. After 4 wks, the new cartilage was assessed for matrix content, superficial zone protein (SZP), and mechanical properties. Results Hyaline articular cartilage was generated, demonstrating the presence of type II collagen and SZP, and the absence of type I collagen. TGF-β1 upregulated collagen synthesis by 175% and glycosaminoglycan synthesis by 75%, resulting in a nearly 200% increase in tensile and compressive moduli. C-ABC significantly increased collagen content, and fibril density and diameter, leading to a 125% increase in tensile modulus. Hydrostatic pressure increased fibril diameter by 30% and tensile modulus by 45%. Combining TGF-β1 with C-ABC synergistically increased collagen content by 300% and tensile strength by 320%, over control. No significant differences were observed between C-ABC/TGF-β1 dual treatment and HP/C-ABC/TGF-β1. Conclusions Employing biochemical, biophysical, and mechanical stimuli generated robust hyaline articular cartilage with a tensile modulus of 2 MPa and a compressive instantaneous modulus of 650 kPa. Using expanded, redifferentiated costochondral cells in the self-assembling process allows for recapitulation of robust mechanical properties, and induced SZP expression, key characteristics of functional articular cartilage. PMID:24330640

The ABC transporter Rv1272c of Mycobacterium tuberculosis enhances the import of long-chain fatty acids in Escherichia coli.

PubMed

Martin, Audrey; Daniel, Jaiyanth

2018-02-05

Mycobacterium tuberculosis (Mtb), which causes tuberculosis, is capable of accumulating triacylglycerol (TAG) by utilizing fatty acids from host cells. ATP-binding cassette (ABC) transporters are involved in transport processes in all organisms. Among the classical ABC transporters in Mtb none have been implicated in fatty acid import. Since the transport of fatty acids from the host cell is important for dormancy-associated TAG synthesis in the pathogen, mycobacterial ABC transporter(s) could potentially be involved in this process. Based on sequence identities with a bacterial ABC transporter that mediates fatty acid import for TAG synthesis, we identified Rv1272c, a hitherto uncharacterized ABC-transporter in Mtb that also shows sequence identities with a plant ABC transporter involved in fatty acid transport. We expressed Rv1272c in E. coli and show that it enhances the import of radiolabeled fatty acids. We also show that Rv1272c causes a significant increase in the metabolic incorporation of radiolabeled long-chain fatty acids into cardiolipin, a tetra-acylated phospholipid, and phosphatidylglycerol in E. coli. This is the first report on the function of Rv1272c showing that it displays a long-chain fatty acid transport function. Copyright © 2018 Elsevier Inc. All rights reserved.

Anti-Campylobacter activity of resveratrol and an extract from waste Pinot noir grape skins and seeds, and resistance of Camp. jejuni planktonic and biofilm cells, mediated via the CmeABC efflux pump.

PubMed

Klančnik, A; Šikić Pogačar, M; Trošt, K; Tušek Žnidarič, M; Mozetič Vodopivec, B; Smole Možina, S

2017-01-01

To define anti-Campylobacter jejuni activity of an extract from waste skins and seeds of Pinot noir grapes (GSS), resveratrol and possible resistance mechanisms, and the influence of these on Camp. jejuni morphology. Using gene-specific knock-out Camp. jejuni mutants and an efflux pump inhibitor, we showed CmeABC as the most active efflux pump for extrusion across the outer membrane of GSS extract and resveratrol. Using polystyrene surface and pig small intestine epithelial (PSI) and human foetal small intestine (H4) cell lines, GSS extract shows an efficient inhibition of adhesion of Camp. jejuni to these abiotic and biotic surfaces. Low doses of GSS extract can inhibit Camp. jejuni adhesion to polystyrene surfaces and to PSI and H4 cells, and can thus modulate Camp. jejuni invasion and intracellular survival. An understanding of the activities of GSS extract and resveratrol as bacterial growth inhibitors and the specific mechanisms of cell accumulation is crucial for our understanding of Camp. jejuni resistance. GSS extract inhibition of Camp. jejuni adhesion to abiotic and biotic surfaces provides a further step towards the application of new innovative strategies to control Campylobacter contamination and infection via the food chain. © 2016 The Society for Applied Microbiology.

Rerouting Cellular Electron Flux To Increase the Rate of Biological Methane Production

PubMed Central

Catlett, Jennie L.; Ortiz, Alicia M.

2015-01-01

Methanogens are anaerobic archaea that grow by producing methane, a gas that is both an efficient renewable fuel and a potent greenhouse gas. We observed that overexpression of the cytoplasmic heterodisulfide reductase enzyme HdrABC increased the rate of methane production from methanol by 30% without affecting the growth rate relative to the parent strain. Hdr enzymes are essential in all known methane-producing archaea. They function as the terminal oxidases in the methanogen electron transport system by reducing the coenzyme M (2-mercaptoethane sulfonate) and coenzyme B (7-mercaptoheptanoylthreonine sulfonate) heterodisulfide, CoM-S-S-CoB, to regenerate the thiol-coenzymes for reuse. In Methanosarcina acetivorans, HdrABC expression caused an increased rate of methanogenesis and a decrease in metabolic efficiency on methylotrophic substrates. When acetate was the sole carbon and energy source, neither deletion nor overexpression of HdrABC had an effect on growth or methane production rates. These results suggest that in cells grown on methylated substrates, the cell compensates for energy losses due to expression of HdrABC with an increased rate of substrate turnover and that HdrABC lacks the appropriate electron donor in acetate-grown cells. PMID:26162885

Inhibition of mitogen-activated protein kinase Erk1/2 promotes protein degradation of ATP binding cassette transporters A1 and G1 in CHO and HuH7 cells.

PubMed

Mulay, Vishwaroop; Wood, Peta; Manetsch, Melanie; Darabi, Masoud; Cairns, Rose; Hoque, Monira; Chan, Karen Cecilia; Reverter, Meritxell; Alvarez-Guaita, Anna; Rye, Kerry-Anne; Rentero, Carles; Heeren, Joerg; Enrich, Carlos; Grewal, Thomas

2013-01-01

Signal transduction modulates expression and activity of cholesterol transporters. We recently demonstrated that the Ras/mitogen-activated protein kinase (MAPK) signaling cascade regulates protein stability of Scavenger Receptor BI (SR-BI) through Proliferator Activator Receptor (PPARα) -dependent degradation pathways. In addition, MAPK (Mek/Erk 1/2) inhibition has been shown to influence liver X receptor (LXR) -inducible ATP Binding Cassette (ABC) transporter ABCA1 expression in macrophages. Here we investigated if Ras/MAPK signaling could alter expression and activity of ABCA1 and ABCG1 in steroidogenic and hepatic cell lines. We demonstrate that in Chinese Hamster Ovary (CHO) cells and human hepatic HuH7 cells, extracellular signal-regulated kinase 1/2 (Erk1/2) inhibition reduces PPARα-inducible ABCA1 protein levels, while ectopic expression of constitutively active H-Ras, K-Ras and MAPK/Erk kinase 1 (Mek1) increases ABCA1 protein expression, respectively. Furthermore, Mek1/2 inhibitors reduce ABCG1 protein levels in ABCG1 overexpressing CHO cells (CHO-ABCG1) and human embryonic kidney 293 (HEK293) cells treated with LXR agonist. This correlates with Mek1/2 inhibition reducing ABCG1 cell surface expression and decreasing cholesterol efflux onto High Density Lipoproteins (HDL). Real Time reverse transcriptase polymerase chain reaction (RT-PCR) and protein turnover studies reveal that Mek1/2 inhibitors do not target transcriptional regulation of ABCA1 and ABCG1, but promote ABCA1 and ABCG1 protein degradation in HuH7 and CHO cells, respectively. In line with published data from mouse macrophages, blocking Mek1/2 activity upregulates ABCA1 and ABCG1 protein levels in human THP1 macrophages, indicating opposite roles for the Ras/MAPK pathway in the regulation of ABC transporter activity in macrophages compared to steroidogenic and hepatic cell types. In summary, this study suggests that Ras/MAPK signaling modulates PPARα- and LXR-dependent protein degradation pathways in a cell-specific manner to regulate the expression levels of ABCA1 and ABCG1 transporters.

Comparison of immunodulatory properties of dental pulp stem cells derived from healthy and inflamed teeth.

PubMed

Yazid, Farinawati Binti; Gnanasegaran, Nareshwaran; Kunasekaran, Wijenthiran; Govindasamy, Vijayendran; Musa, Sabri

2014-12-01

The aim of this study was to investigate the immunodulatory properties of dental pulp stem cells derived from healthy (SCD) and inflamed pulp deciduous (SCDIP) tissues. The overall hypothesis is that SCDIP possess equal immune properties with SCD and could be used as an alternative tissue source in regenerative medicine. An intra-oral examination was carried out to assess the status of the pulp tissues and group them according to healthy or inflamed. Primary cells were established from these groups, and basic mesenchymal stem cells (MSC) characterizations were conducted. The expression of human leukocyte antigen (HLA), namely HLA-G, HLA-DR, and HLA-ABC were examined in both cell lines using flow cytometry. We further compared the immunosuppressive effects of SCD and SCDIP on phytohemagglutinin-induced T cell proliferation. Supernatants were tested for cytokine profiling using multiplex array. While SCD exhibited typical MSC characteristics, SCDIP on the other hand, did not. Compared with SCDIP, SCD effectively suppresses mitogen-induced T cells proliferation in a dose-dependent manner, as well as express a higher percentage of HLA-ABC and HLA-G. In addition, levels of several cytokines, such as TNF-α, TNF-β, and IL-2, were drastically suppressed in SCD than SCDIP. Furthermore, a high level of IL-10, an important anti-inflammatory cytokine, was present in SCD compared with SCDIP. These findings suggest that SCDIP is highly dysfunctional in terms of their stemness and immunomodulatory properties. SCDIP is not a viable therapeutic cell source especially when used in graft versus host disease (GvHD) and organ rejection.

Comparison of the algorithms classifying the ABC and GCB subtypes in diffuse large B-cell lymphoma.

PubMed

Boltežar, Lučka; Prevodnik, Veronika Kloboves; Perme, Maja Pohar; Gašljević, Gorana; Novaković, Barbara Jezeršek

2018-05-01

Different immunohistochemical algorithms for the classification of the activated B-cell (ABC) and germinal center B-cell (GCB) subtypes of diffuse large B-cell lymphoma (DLBCL) are applied in different laboratories. In the present study, 127 patients with DLCBL were investigated, all treated with rituximab and cyclophosphamide, hydroxydaunorubicin, oncovin and prednisone (CHOP) or CHOP-like regimens between April 2004 and December 2010. Multi-tumor tissue microarrays were prepared and were tested according to 4 algorithms: Hans; modified Hans; Choi; and modified Choi. For 39 patients, the flow cytometric quantification of CD19 and CD20 antigen expression was performed and the level of expression presented as molecules of equivalent soluble fluorochrome units. The Choi algorithm was demonstrated to be prognostic for OS and classified patients into the GCB subgroup with an HR of 0.91. No difference in the expression of the CD19 antigen between the ABC and GCB groups was observed, but the ABC subtype exhibited a decreased expression of the CD20 antigen compared with the GCB subtype.

Quantification and in situ localisation of abcb1 and abcc9genes in toxicant-exposed sea urchin embryos.

PubMed

Bošnjak, Ivana; Pleić, Ivana Lepen; Borra, Marco; Mladineo, Ivona

2013-12-01

A multixenobiotic resistance (MXR) mechanism mediated by ABC binding cassette (ABC) transport proteins is an efficient chemical defence mechanism in sea urchin embryos. The aim of our work was to evidence whether exposure to sub-lethal doses of specific contaminants (oxybenzone (OXI), mercuric chloride (HgCl2) and trybutiltin (TBT)) would induce MXR transporter activity during embryonic development (from zygote to blastula stage) in purple sea urchin (Paracentrotus lividus) embryos. Further, we present data on molecular identification, transport function, expression levels and gene localisation of two ABC efflux transporters-P-glycoprotein (ABCB1/P-gp) and sulfonylurea-receptor-like protein (ABCC9/SUR-like). Partial cDNA sequences of abcb1 and abcc9 were identified and quantitative PCR (qPCR) evidenced an increase in mRNA transcript levels of both ABC transporters during the two-cell, as well as an overall decrease during the blastulae stage. Calcein-AM efflux activity assay indicated the activation of multidrug resistance-associated protein/ABCC-like transport in the presence of HgCl2 and TBT in exposed blastulae. The in situ hybridisation of the two-cell and blastula stages showed ubiquitous localisation of both transcripts within cells, supporting qPCR data. In conclusion, ABCB1 and ABCC9 are constitutive, as are HgCl2, TBT and OXI-inducible ABC membrane transporters, coexpressed in the zygote, two-cell and blastula stages of the P. lividus. Their ubiquitous cell localisation further fortifies their protective role in early embryonic development.

eUnaG: a new ligand-inducible fluorescent reporter to detect drug transporter activity in live cells

PubMed Central

Yeh, Johannes T.-H.; Nam, Kwangho; Yeh, Joshua T.-H.; Perrimon, Norbert

2017-01-01

The absorption, distribution, metabolism and excretion (ADME) of metabolites and toxic organic solutes are orchestrated by the ATP-binding cassette (ABC) transporters and the organic solute carrier family (SLC) proteins. A large number of ABC and SLC transpoters exist; however, only a small number have been well characterized. To facilitate the analysis of these transporters, which is important for drug safety and physiological studies, we developed a sensitive genetically encoded bilirubin (BR)-inducible fluorescence sensor (eUnaG) to detect transporter-coupled influx/efflux of organic compounds. This sensor can be used in live cells to measure transporter activity, as excretion of BR depends on ABC and SLC transporters. Applying eUnaG in functional RNAi screens, we characterize l(2)03659 as a Drosophila multidrug resistant-associated ABC transporter. PMID:28176814

Enzastaurin inhibits ABCB1-mediated drug efflux independently of effects on protein kinase C signalling and the cellular p53 status.

PubMed

Michaelis, Martin; Rothweiler, Florian; Löschmann, Nadine; Sharifi, Mohsen; Ghafourian, Taravat; Cinatl, Jindrich

2015-07-10

The PKCβ inhibitor enzastaurin was tested in parental neuroblastoma and rhabdomyosarcoma cell lines, their vincristine-resistant sub-lines, primary neuroblastoma cells, ABCB1-transduced, ABCG2-transduced, and p53-depleted cells. Enzastaurin IC50s ranged from 3.3 to 9.5 μM in cell lines and primary cells independently of the ABCB1, ABCG2, or p53 status. Enzastaurin 0.3125 μM interfered with ABCB1-mediated drug transport. PKCα and PKCβ may phosphorylate and activate ABCB1 under the control of p53. However, enzastaurin exerted similar effects on ABCB1 in the presence or absence of functional p53. Also, enzastaurin inhibited PKC signalling only in concentrations ≥ 1.25 μM. The investigated cell lines did not express PKCβ. PKCα depletion reduced PKC signalling but did not affect ABCB1 activity. Intracellular levels of the fluorescent ABCB1 substrate rhodamine 123 rapidly decreased after wash-out of extracellular enzastaurin, and enzastaurin induced ABCB1 ATPase activity resembling the ABCB1 substrate verapamil. Computational docking experiments detected a direct interaction of enzastaurin and ABCB1. These data suggest that enzastaurin directly interferes with ABCB1 function. Enzastaurin further inhibited ABCG2-mediated drug transport but by a different mechanism since it reduced ABCG2 ATPase activity. These findings are important for the further development of therapies combining enzastaurin with ABC transporter substrates.

Temporal dynamics of the ABC transporter response to insecticide treatment: insights from the malaria vector Anopheles stephensi

NASA Astrophysics Data System (ADS)

Epis, Sara; Porretta, Daniele; Mastrantonio, Valentina; Urbanelli, Sandra; Sassera, Davide; De Marco, Leone; Mereghetti, Valeria; Montagna, Matteo; Ricci, Irene; Favia, Guido; Bandi, Claudio

2014-12-01

In insects, ABC transporters have been shown to contribute to defence/resistance to insecticides by reducing toxic concentrations in cells/tissues. Despite the extensive studies about this detoxifying mechanism, the temporal patterns of ABC transporter activation have been poorly investigated. Using the malaria vector Anopheles stephensi as a study system, we investigated the expression profile of ABC genes belonging to different subfamilies in permethrin-treated larvae at different time points (30 min to 48 h). Our results showed that the expression of ABCB and ABCG subfamily genes was upregulated at 1 h after treatment, with the highest expression observed at 6 h. Therefore, future investigations on the temporal dynamics of ABC gene expression will allow a better implementation of insecticide treatment regimens, including the use of specific inhibitors of ABC efflux pumps.

TaABC1, a member of the activity of bc1 complex protein kinase family from common wheat, confers enhanced tolerance to abiotic stresses in Arabidopsis

PubMed Central

Wang, Caixiang; Jing, Ruilian; Mao, Xinguo; Chang, Xiaoping; Li, Ang

2011-01-01

Abiotic stresses such as drought, salinity, and low temperature have drastic effects on plant growth and development. However, the molecular mechanisms regulating biochemical and physiological changes in response to stresses are not well understood. Protein kinases are major signal transduction factors among the reported molecular mechanisms mediating acclimation to environmental changes. Protein kinase ABC1 (activity of bc1 complex) is involved in regulating coenzyme Q biosynthesis in mitochondria in yeast (Saccharomyces cersvisiae), and in balancing oxidative stress in chloroplasts in Arabidopsis thaliana. In the current study, TaABC1 (Triticum aestivum L. activity of bc1 complex) protein kinase was localized to the cell membrane, cytoplasm, and nucleus. The effects of overexpressing TaABC1 in transgenic Arabidopsis plants on responses to drought, salt, and cold stress were further investigated. Transgenic Arabidopsis overexpressing the TaABC1 protein showed lower water loss and higher osmotic potential, photochemistry efficiency, and chlorophyll content, while cell membrane stability and controlled reactive oxygen species homeostasis were maintained. In addition, overexpression of TaABC1 increased the expression of stress-responsive genes, such as DREB1A, DREB2A, RD29A, ABF3, KIN1, CBF1, LEA, and P5CS, detected by real-time PCR analysis. The results suggest that TaABC1 overexpression enhances drought, salt, and cold stress tolerance in Arabidopsis, and imply that TaABC1 may act as a regulatory factor involved in a multiple stress response pathways. PMID:21115661

High absolute basophil count is a powerful independent predictor of inferior overall survival in patients with primary myelofibrosis.

PubMed

Lucijanic, Marko; Livun, Ana; Stoos-Veic, Tajana; Pejsa, Vlatko; Jaksic, Ozren; Cicic, David; Lucijanic, Jelena; Romic, Zeljko; Orehovec, Biserka; Aralica, Gorana; Miletic, Marko; Kusec, Rajko

2018-05-01

To investigate the clinical and prognostic significance of absolute basophil count (ABC) in patients with primary myelofibrosis (PMF). We retrospectively investigated 58 patients with PMF treated in our institution in the period from 2006 to 2017. ABC was obtained in addition to other hematological and clinical parameters. Patients were separated into high and low ABC groups using the Receiver operating characteristic curve analysis. ABC was higher in PMF patients than in healthy controls (P < 0.001). Patients with high ABC had higher white blood cells (P < 0.001), higher red cell distribution width (P = 0.035), higher lactate dehydrogenase (P < 0.001), more frequently had circulatory blasts (P < 0.001), constitutional symptoms (P = 0.030) and massive splenomegaly (P = 0.014). ABC was also positively correlated with absolute monocyte count (AMC) (P < 0.001) and other components of differential blood count. There was no difference in ABC regarding driver mutations or degree of bone marrow fibrosis. Univariately, high ABC was significantly associated with inferior overall survival (hazard ratio (HR) 4.79, P < 0.001). This effect remained statistically significant (HR 4.27, P = 0.009) in a multivariate Cox regression model adjusted for age, gender, Dynamic International Prognostic Scoring System (HR 2.6, P = 0.001) and AMC (HR 8.45, P = 0.002). High ABC reflects higher disease activity and stronger proliferative potential of disease. ABC and AMC independently predict survival and therefore seem to reflect different underlying pathophysiologic processes. Hence, both have a potential for improvement of current prognostic scores. Basophils represent a part of malignant clone in PMF and are associated with unfavorable disease features and poor prognosis which is independent of currently established prognostic scoring system and monocytosis.

ABCB1 and ABCC1-like transporters in immune system cells from sea urchins Echinometra lucunter and Echinus esculentus and oysters Crassostrea gasar and Crassostrea gigas.

PubMed

Marques-Santos, Luis Fernando; Hégaret, Hélène; Lima-Santos, Leonardo; Queiroga, Fernando Ramos; da Silva, Patricia Mirella

2017-11-01

ABC transporters activity and expression have been associated with the multixenobiotic resistance phenotype (MXR). The activity of these proteins leads to a reduction in the intracellular concentration of several xenobiotics, thus reducing their toxicity. However, little attention has been given to the expression of ABC transporters in marine invertebrates and few studies have investigated their role in immune system cells of sea urchins and shellfish bivalves. The aim of the present study was to investigate the activity of the ABC transporters ABCB1 and ABCC1 in immune system cells of sea urchins (coelomocytes) and oysters (hemocytes) from different climatic regions (Brazil and France). Sea urchins and oysters were collected at Paraíba coast; Brazil (Echinometra lucunter and Crassostrea gasar) and Rade of Brest; France (Echinus esculentus and Crassostrea gigas). Coelomocytes and hemocytes were stained with the ABC transporter substrate calcein-AM and dye accumulation analyzed under flow cytometry. Reversin 205 (ABCB1 transporter blocker) and MK571 (ABCC1 transporter blocker) were used as pharmacological tools to investigate ABC transporter activity. A different pattern of calcein accumulation was observed in coelomocytes: phagocytes > colorless spherulocytes > vibrate cells > red spherulocytes. The treatment with MK571 increased calcein fluorescence levels in coelomocytes from both species. However, reversin 205 treatment was not able to increase calcein fluorescence in E. esculentus coelomocytes. These data suggest that ABCC1-like transporter activity is present in both sea urchin species, but ABCB1-like transporter activity might only be present in E. lucunter coelomocytes. The activity of ABCC1-like transporter was observed in all cell types from both bivalve species. However, reversin 205 only increased calcein accumulation in hyalinocytes of the oyster C. gasar, suggesting the absence of ABCB1-like transporter activity in all other cell types, including hyalinocytes from the oyster C. gigas. Additionally, our results showed that C. gigas exhibited higher activity of ABCC1-like transporter in all hemocyte types than C. gasar. The present work is the first to characterize ABCB1 and ABCC1-like transporter activity in the immune system cells of sea urchins E. lucunter and E. esculentus and oysters. Our findings encourage the performing studies regarding ABC transporters activity/expression in immune system cells form marine invertebrates under stress conditions and the possible use of ABC transporters as biomarkers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anticancer Effects of the Nitric Oxide-Modified Saquinavir Derivative Saquinavir-NO against Multidrug-Resistant Cancer Cells12

PubMed Central

Rothweiler, Florian; Michaelis, Martin; Brauer, Peter; Otte, Jürgen; Weber, Kristoffer; Fehse, Boris; Doerr, Hans Wilhelm; Wiese, Michael; Kreuter, Jörg; Al-Abed, Yousef; Nicoletti, Ferdinando; Cinatl, Jindrich

2010-01-01

The human immunodeficiency virus (HIV) protease inhibitor saquinavir shows anticancer activity. Although its nitric oxide-modified derivative saquinavir-NO (saq-NO) was less toxic to normal cells, it exerted stronger inhibition of B16 melanoma growth in syngeneic C57BL/6 mice than saquinavir did. Saq-NO has been shown to block proliferation, upregulate p53 expression, and promote differentiation of C6 glioma and B16 cells. The anticancer activity of substances is frequently hampered by cancer cell chemoresistance mechanisms. Therefore, we here investigated the roles of p53 and the ATP-binding cassette (ABC) transporters P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), and breast cancer resistance protein 1 (BCRP1) in cancer cell sensitivity to saq-NO to get more information about the potential of saq-NO as anticancer drug. Saq-NO exerted anticancer effects in lower concentrations than saquinavir in a panel of human cancer cell lines. Neither p53 mutation or depletion nor expression of P-gp, MRP1, or BCRP1 affected anticancer activity of saq-NO or saquinavir. Moreover, saq-NO sensitized P-gp-, MRP1-, or BCRP1-expressing cancer cells to chemotherapy. Saq-NO induced enhanced sensitization of P-gp- or MRP1-expressing cancer cells to chemotherapy compared with saquinavir, whereas both substances similarly sensitized BCRP1-expressing cells. Washout kinetics and ABC transporter ATPase activities demonstrated that saq-NO is a substrate of P-gp as well as of MRP1. These data support the further investigation of saq-NO as an anticancer drug, especially in multidrug-resistant tumors. PMID:21170266

Inhibition of sirtuins 1 and 2 impairs cell survival and migration and modulates the expression of P-glycoprotein and MRP3 in hepatocellular carcinoma cell lines.

PubMed

Ceballos, María Paula; Decándido, Giulia; Quiroga, Ariel Darío; Comanzo, Carla Gabriela; Livore, Verónica Inés; Lorenzetti, Florencia; Lambertucci, Flavia; Chazarreta-Cifre, Lorena; Banchio, Claudia; Alvarez, María de Luján; Mottino, Aldo Domingo; Carrillo, María Cristina

2018-06-01

Sirtuins (SIRTs) 1 and 2 deacetylases are overexpressed in hepatocellular carcinoma (HCC) and are associated with tumoral progression and multidrug resistance (MDR). In this study we analyzed whether SIRTs 1 and 2 activities blockage was able to affect cellular survival and migration and to modulate p53 and FoxO1 acetylation in HepG2 and Huh7 cells. Moreover, we analyzed ABC transporters P-glycoprotein (P-gp) and multidrug resistance-associated protein 3 (MRP3) expression. We used cambinol and EX-527 as SIRTs inhibitors. Both drugs reduced cellular viability, number of colonies and cellular migration and augmented apoptosis. In 3D cultures, SIRTs inhibitors diminished spheroid growth and viability. 3D culture was less sensitive to drugs than 2D culture. The levels of acetylated p53 and FoxO1 increased after treatments. Drugs induced a decrease in ABC transporters mRNA and protein levels in HepG2 cells; however, only EX-527 was able to reduce MRP3 mRNA and protein levels in Huh7 cells. This is the first work demonstrating the regulation of MRP3 by SIRTs. In conclusion, both drugs decreased HCC cells survival and migration, suggesting SIRTs 1 and 2 activities blockage could be beneficial during HCC therapy. Downregulation of the expression of P-gp and MRP3 supports the potential application of SIRTs 1 and 2 inhibitions in combination with conventional chemotherapy. Copyright © 2018 Elsevier B.V. All rights reserved.

ABC Transporters Involved in Export of Cell Surface Glycoconjugates

PubMed Central

Cuthbertson, Leslie; Kos, Veronica; Whitfield, Chris

2010-01-01

Summary: Complex glycoconjugates play critical roles in the biology of microorganisms. Despite the remarkable diversity in glycan structures and the bacteria that produce them, conserved themes are evident in the biosynthesis-export pathways. One of the primary pathways involves representatives of the ATP-binding cassette (ABC) transporter superfamily. These proteins are responsible for the export of a wide variety of cell surface oligo- and polysaccharides in both Gram-positive and Gram-negative bacteria. Recent investigations of the structure and function of ABC transporters involved in the export of lipopolysaccharide O antigens have revealed two fundamentally different strategies for coupling glycan polymerization to export. These mechanisms are distinguished by the presence (or absence) of characteristic nonreducing terminal modifications on the export substrates, which serve as chain termination and/or export signals, and by the presence (or absence) of a discrete substrate-binding domain in the nucleotide-binding domain polypeptide of the ABC transporter. A bioinformatic survey examining ABC exporters from known oligo- and polysaccharide biosynthesis loci identifies conserved nucleotide-binding domain protein families that correlate well with themes in the structures and assembly of glycans. The familial relationships among the ABC exporters generate hypotheses concerning the biosynthesis of structurally diverse oligo- and polysaccharides, which play important roles in the biology of bacteria with different lifestyles. PMID:20805402

Identification of biomarkers associated with partial epithelial to mesenchymal transition in the secretome of slug over-expressing hepatocellular carcinoma cells.

PubMed

Karaosmanoğlu, Oğuzhan; Banerjee, Sreeparna; Sivas, Hülya

2018-06-01

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. Complete epithelial to mesenchymal transition (EMT) has long been considered as a crucial step for metastasis initiation. It has, however, become apparent that many carcinoma cells can metastasize without complete loss of epithelial traits or with incomplete gain of mesenchymal traits, i.e., partial EMT. Here, we aimed to determine the similarities and differences between complete and partial EMT through over-expression of the EMT-associated transcription factor Slug in different HCC-derived cell lines. Slug over-expressing HCC-derived HepG2 and Huh7 cells were assessed for their EMT, chemo-resistance and stemness features using Western blotting, qRT-PCR, neutral red uptake, doxorubicin accumulation and scratch wound healing assays. We also collected conditioned media from Slug over-expressing HCC cells and analyzed its exosomal protein content for the presence of chemo-resistance and partial EMT markers using MALDI-TOF/TOF and ELISA assays, respectively. We found that Slug over-expression resulted in the induction of both complete and partial EMT in the different HCC-derived cell lines tested. Complete EMT was characterized by downregulation of E-cadherin and upregulation of ZEB2. Partial EMT was characterized by upregulation of E-cadherin and downregulation of vimentin and ZEB2. Interestingly, we found that Slug induced chemo-resistance through downregulation of the ATP binding cassette (ABC) transporter ABCB1 and upregulation of the ABC transporter ABCG2, as well as through expression of CD133, a stemness marker that exhibited a similar expression pattern in cells with either a complete or a partial EMT phenotype. In addition, we found that Slug-mediated partial EMT was associated with enhanced exosomal secretion of post-translationally modified fibronectin 1 (FN1), collagen type II alpha 1 (COL2A1) and native fibrinogen gamma chain (FGG). From our data we conclude that the exosomal proteins identified may be considered as potential non-invasive biomarkers for chemo-resistance and partial EMT in HCC.

LC-MS/MS Based Quantitation of ABC and SLC Transporter Proteins in Plasma Membranes of Cultured Primary Human Retinal Pigment Epithelium Cells and Immortalized ARPE19 Cell Line.

PubMed

Pelkonen, Laura; Sato, Kazuki; Reinisalo, Mika; Kidron, Heidi; Tachikawa, Masanori; Watanabe, Michitoshi; Uchida, Yasuo; Urtti, Arto; Terasaki, Tetsuya

2017-03-06

The retinal pigment epithelium (RPE) forms the outer blood-retinal barrier between neural retina and choroid. The RPE has several important vision supporting functions, such as transport mechanisms that may also modify pharmacokinetics in the posterior eye segment. Expression of plasma membrane transporters in the RPE cells has not been quantitated. The aim of this study was to characterize and compare transporter protein expression in the ARPE19 cell line and hfRPE (human fetal RPE) cells by using quantitative targeted absolute proteomics (QTAP). Among 41 studied transporters, 16 proteins were expressed in hfRPE and 13 in ARPE19 cells. MRP1, MRP5, GLUT1, 4F2hc, TAUT, CAT1, LAT1, and MATE1 proteins were detected in both cell lines within 4-fold differences. MPR7, OAT2 and RFC1 were detected in the hfRPE cells, but their expression levels were below the limit of quantification in ARPE19 cells. PCFT was detected in both studied cell lines, but the expression was over 4-fold higher in hfRPE cells. MCT1, MCT4, MRP4, and Na + /K + ATPase were upregulated in the ARPE19 cell line showing over 4-fold differences in the quantitative expression values. Expression levels of 25 transporters were below the limit of quantification in both cell models. In conclusion, we present the first systematic and quantitative study on transporter protein expression in the plasma membranes of ARPE19 and hfRPE cells. Overall, transporter expression in the ARPE19 and hfRPE cells correlated well and the absolute expression levels were similar, but not identical. The presented quantitative expression levels could be a useful basis for further studies on drug permeation in the outer blood-retinal barrier.

Expression of Genes for Drug Transporters in the Human Female Genital Tract and Modulatory Effect of Antiretroviral Drugs.

PubMed

Hijazi, Karolin; Cuppone, Anna M; Smith, Kieron; Stincarelli, Maria A; Ekeruche-Makinde, Julia; De Falco, Giulia; Hold, Georgina L; Shattock, Robin; Kelly, Charles G; Pozzi, Gianni; Iannelli, Francesco

2015-01-01

Anti-retroviral (ARV) -based microbicides are one of the strategies pursued to prevent HIV-1 transmission. Delivery of ARV drugs to subepithelial CD4+ T cells at concentrations for protection is likely determined by drug transporters expressed in the cervicovaginal epithelium. To define the role of drug transporters in mucosal disposition of topically applied ARV-based microbicides, these must be tested in epithelial cell line-based biopharmaceutical assays factoring the effect of relevant drug transporters. We have characterised gene expression of influx and efflux drug transporters in a panel of cervicovaginal cell lines and compared this to expression in cervicovaginal tissue. We also investigated the effect of dapivirine, darunavir and tenofovir, currently at advanced stages of microbicides development, on expression of drug transporters in cell lines. Expression of efflux ABC transporters in cervical tissue was best represented in HeLa, Ect1/E6E7 and End1/E6E7 cell lines. Expression of influx OCT and ENT transporters in ectocervix matched expression in Hela while expression of influx SLCO transporters in vagina was best reflected in VK2/E6E7 cell line. Stimulation with darunavir and dapivirine upregulated MRP transporters, including MRP5 involved in transport of tenofovir. Dapivirine also significantly downregulated tenofovir substrate MRP4 in cervical cell lines. Treatment with darunavir and dapivirine showed no significant effect on expression of BCRP, MRP2 and P-glycoprotein implicated in efflux of different ARV drugs. Darunavir strongly induced expression in most cell lines of CNT3 involved in cell uptake of nucleotide/nucleoside analogue reverse transcriptase inhibitors and SLCO drug transporters involved in cell uptake of protease inhibitors. This study provides insight into the suitability of cervicovaginal cell lines for assessment of ARV drugs in transport kinetics studies. The modulatory effect of darunavir and dapivirine on expression of drug transporters involved in transport of tenofovir points to the possibility of combining these drugs to improve retention of individual drugs at target tissues.

Expression of Genes for Drug Transporters in the Human Female Genital Tract and Modulatory Effect of Antiretroviral Drugs

PubMed Central

Hijazi, Karolin; Cuppone, Anna M.; Smith, Kieron; Stincarelli, Maria A.; Ekeruche-Makinde, Julia; De Falco, Giulia; Hold, Georgina L.; Shattock, Robin; Kelly, Charles G.; Pozzi, Gianni; Iannelli, Francesco

2015-01-01

Anti-retroviral (ARV) –based microbicides are one of the strategies pursued to prevent HIV-1 transmission. Delivery of ARV drugs to subepithelial CD4+ T cells at concentrations for protection is likely determined by drug transporters expressed in the cervicovaginal epithelium. To define the role of drug transporters in mucosal disposition of topically applied ARV-based microbicides, these must be tested in epithelial cell line-based biopharmaceutical assays factoring the effect of relevant drug transporters. We have characterised gene expression of influx and efflux drug transporters in a panel of cervicovaginal cell lines and compared this to expression in cervicovaginal tissue. We also investigated the effect of dapivirine, darunavir and tenofovir, currently at advanced stages of microbicides development, on expression of drug transporters in cell lines. Expression of efflux ABC transporters in cervical tissue was best represented in HeLa, Ect1/E6E7 and End1/E6E7 cell lines. Expression of influx OCT and ENT transporters in ectocervix matched expression in Hela while expression of influx SLCO transporters in vagina was best reflected in VK2/E6E7 cell line. Stimulation with darunavir and dapivirine upregulated MRP transporters, including MRP5 involved in transport of tenofovir. Dapivirine also significantly downregulated tenofovir substrate MRP4 in cervical cell lines. Treatment with darunavir and dapivirine showed no significant effect on expression of BCRP, MRP2 and P-glycoprotein implicated in efflux of different ARV drugs. Darunavir strongly induced expression in most cell lines of CNT3 involved in cell uptake of nucleotide/nucleoside analogue reverse transcriptase inhibitors and SLCO drug transporters involved in cell uptake of protease inhibitors. This study provides insight into the suitability of cervicovaginal cell lines for assessment of ARV drugs in transport kinetics studies. The modulatory effect of darunavir and dapivirine on expression of drug transporters involved in transport of tenofovir points to the possibility of combining these drugs to improve retention of individual drugs at target tissues. PMID:26102284

A retrospective case-cohort study comparing treatment outcomes in abacavir versus stavudine containing first line antiretroviral treatment regimens in children <3yrs old, at a paediatric programme based in Soweto, South Africa

PubMed Central

Otwombe, Kennedy; Lazarus, Erica; Liberty, Afaaf; Gray, Glenda E.; Greeff, Oppel B. W.; Violari, Avy

2017-01-01

Introduction The current World Health Organization guideline for first line antiretroviral therapy (ART) in HIV-infected children recommends the use of abacavir and lamivudine as nucleoside backbones and no longer includes stavudine. We compared treatment outcomes with abacavir (ABC) versus stavudine (d4T) in a cohort of HIV-1 infected children 6 and 12 months after antiretroviral therapy was initiated. Methods This was a retrospective case-cohort study, using programmatic data from children enrolled in the Paediatric Wellness Programme at the Perinatal HIV Research Unit in Soweto, South Africa between 2005 and 2013. Children on abacavir/stavudine who had initiated ART at age <3 years with a regimen including lamivudine and lopinavir/ritonavir and had at least one 6 or 12 month viral load result were eligible. All ABC cases identified were matched for age at ART initiation and gender to eligible d4T controls (1:2). Outcomes analysed at 6 and 12 months post ART initiation included virological failure, mortality, immunological failure and anthropometry. Chi-square tests compared categorical measures while Kruskal-Wallis compared continuous measures. Results We identified 57 eligible ABC cases and selected 114 matched d4T controls. Overall, 57% were females and 89% started treatment at age <1year. The median age at ART initiation was 3.11 (IQR: 1.98–6.05) months. There was no difference in the proportion of children virologically suppressed between the groups at 6 (ABC 54.5% vs. d4T 67.0%, p = 0.125) and 12 (ABC 66.7% vs. d4T 71.6%, p = 0.53) months post ART-initiation. The proportion of children with adherence levels >90% for ABC and d4T were similar too (95% in ABC vs. 86% in d4T, p = 0.10). The proportion of children who died over 12 months was 3.5% in the ABC and 7.9% in the d4T group (p = 0.27). Similarly, the anthropometric measures were comparable. Conclusions It is reassuring that in the short term, in this group of patients, the treatment outcomes were similar. PMID:28686654

A retrospective case-cohort study comparing treatment outcomes in abacavir versus stavudine containing first line antiretroviral treatment regimens in children <3yrs old, at a paediatric programme based in Soweto, South Africa.

PubMed

Cassim, Haseena; Otwombe, Kennedy; Lazarus, Erica; Liberty, Afaaf; Gray, Glenda E; Greeff, Oppel B W; Violari, Avy

2017-01-01

The current World Health Organization guideline for first line antiretroviral therapy (ART) in HIV-infected children recommends the use of abacavir and lamivudine as nucleoside backbones and no longer includes stavudine. We compared treatment outcomes with abacavir (ABC) versus stavudine (d4T) in a cohort of HIV-1 infected children 6 and 12 months after antiretroviral therapy was initiated. This was a retrospective case-cohort study, using programmatic data from children enrolled in the Paediatric Wellness Programme at the Perinatal HIV Research Unit in Soweto, South Africa between 2005 and 2013. Children on abacavir/stavudine who had initiated ART at age <3 years with a regimen including lamivudine and lopinavir/ritonavir and had at least one 6 or 12 month viral load result were eligible. All ABC cases identified were matched for age at ART initiation and gender to eligible d4T controls (1:2). Outcomes analysed at 6 and 12 months post ART initiation included virological failure, mortality, immunological failure and anthropometry. Chi-square tests compared categorical measures while Kruskal-Wallis compared continuous measures. We identified 57 eligible ABC cases and selected 114 matched d4T controls. Overall, 57% were females and 89% started treatment at age <1year. The median age at ART initiation was 3.11 (IQR: 1.98-6.05) months. There was no difference in the proportion of children virologically suppressed between the groups at 6 (ABC 54.5% vs. d4T 67.0%, p = 0.125) and 12 (ABC 66.7% vs. d4T 71.6%, p = 0.53) months post ART-initiation. The proportion of children with adherence levels >90% for ABC and d4T were similar too (95% in ABC vs. 86% in d4T, p = 0.10). The proportion of children who died over 12 months was 3.5% in the ABC and 7.9% in the d4T group (p = 0.27). Similarly, the anthropometric measures were comparable. It is reassuring that in the short term, in this group of patients, the treatment outcomes were similar.

Proteasomal degradation of sphingosine kinase 1 and inhibition of dihydroceramide desaturase by the sphingosine kinase inhibitors, SKi or ABC294640, induces growth arrest in androgen-independent LNCaP-AI prostate cancer cells.

PubMed

McNaughton, Melissa; Pitman, Melissa; Pitson, Stuart M; Pyne, Nigel J; Pyne, Susan

2016-03-29

Sphingosine kinases (two isoforms termed SK1 and SK2) catalyse the formation of the bioactive lipid sphingosine 1-phosphate. We demonstrate here that the SK2 inhibitor, ABC294640 (3-(4-chlorophenyl)-adamantane-1-carboxylic acid (pyridin-4-ylmethyl)amide) or the SK1/SK2 inhibitor, SKi (2-(p-hydroxyanilino)-4-(p-chlorophenyl)thiazole)) induce the proteasomal degradation of SK1a (Mr = 42 kDa) and inhibit DNA synthesis in androgen-independent LNCaP-AI prostate cancer cells. These effects are recapitulated by the dihydroceramide desaturase (Des1) inhibitor, fenretinide. Moreover, SKi or ABC294640 reduce Des1 activity in Jurkat cells and ABC294640 induces the proteasomal degradation of Des1 (Mr = 38 kDa) in LNCaP-AI prostate cancer cells. Furthermore, SKi or ABC294640 or fenretinide increase the expression of the senescence markers, p53 and p21 in LNCaP-AI prostate cancer cells. The siRNA knockdown of SK1 or SK2 failed to increase p53 and p21 expression, but the former did reduce DNA synthesis in LNCaP-AI prostate cancer cells. Moreover, N-acetylcysteine (reactive oxygen species scavenger) blocked the SK inhibitor-induced increase in p21 and p53 expression but had no effect on the proteasomal degradation of SK1a. In addition, siRNA knockdown of Des1 increased p53 expression while a combination of Des1/SK1 siRNA increased the expression of p21. Therefore, Des1 and SK1 participate in regulating LNCaP-AI prostate cancer cell growth and this involves p53/p21-dependent and -independent pathways. Therefore, we propose targeting androgen-independent prostate cancer cells with compounds that affect Des1/SK1 to modulate both de novo and sphingolipid rheostat pathways in order to induce growth arrest.

Extensive sphingolipid depletion does not affect lipid raft integrity or lipid raft localization and efflux function of the ABC transporter MRP1.

PubMed

Klappe, Karin; Dijkhuis, Anne-Jan; Hummel, Ina; van Dam, Annie; Ivanova, Pavlina T; Milne, Stephen B; Myers, David S; Brown, H Alex; Permentier, Hjalmar; Kok, Jan W

2010-09-15

We show that highly efficient depletion of sphingolipids in two different cell lines does not abrogate the ability to isolate Lubrol-based DRMs (detergent-resistant membranes) or detergent-free lipid rafts from these cells. Compared with control, DRM/detergent-free lipid raft fractions contain equal amounts of protein, cholesterol and phospholipid, whereas the classical DRM/lipid raft markers Src, caveolin-1 and flotillin display the same gradient distribution. DRMs/detergent-free lipid rafts themselves are severely depleted of sphingolipids. The fatty acid profile of the remaining sphingolipids as well as that of the glycerophospholipids shows several differences compared with control, most prominently an increase in highly saturated C(16) species. The glycerophospholipid headgroup composition is unchanged in sphingolipid-depleted cells and cell-derived detergent-free lipid rafts. Sphingolipid depletion does not alter the localization of MRP1 (multidrug-resistance-related protein 1) in DRMs/detergent-free lipid rafts or MRP1-mediated efflux of carboxyfluorescein. We conclude that extensive sphingolipid depletion does not affect lipid raft integrity in two cell lines and does not affect the function of the lipid-raft-associated protein MRP1.

Extensive sphingolipid depletion does not affect lipid raft integrity or lipid raft localization and efflux function of the ABC transporter MRP1

PubMed Central

Klappe, Karin; Dijkhuis, Anne-Jan; Hummel, Ina; vanDam, Annie; Ivanova, Pavlina T.; Milne, Stephen B.; Myers, David S.; Brown, H. Alex; Permentier, Hjalmar; Kok, Jan W.

2013-01-01

We show that highly efficient depletion of sphingolipids in two different cell lines does not abrogate the ability to isolate Lubrol-based DRMs (detergent-resistant membranes) or detergent-free lipid rafts from these cells. Compared with control, DRM/detergent-free lipid raft fractions contain equal amounts of protein, cholesterol and phospholipid, whereas the classical DRM/lipid raft markers Src, caveolin-1 and flotillin display the same gradient distribution. DRMs/detergent-free lipid rafts themselves are severely depleted of sphingolipids. The fatty acid profile of the remaining sphingolipids as well as that of the glycerophospholipids shows several differences compared with control, most prominently an increase in highly saturated C16 species. The glycerophospholipid headgroup composition is unchanged in sphingolipid-depleted cells and cell-derived detergent-free lipid rafts. Sphingolipid depletion does not alter the localization of MRP1 (multidrug-resistance-related protein 1) in DRMs/detergent-free lipid rafts or MRP1-mediated efflux of carboxyfluorescein. We conclude that extensive sphingolipid depletion does not affect lipid raft integrity in two cell lines and does not affect the function of the lipid-raft-associated protein MRP1. PMID:20604746

Characterisation of single domain ATP-binding cassette protien homologues of Theileria parva.

PubMed

Kibe, M K; Macklin, M; Gobright, E; Bishop, R; Urakawa, T; ole-MoiYoi, O K

2001-09-01

Two distinct genes encoding single domain, ATP-binding cassette transport protein homologues of Theileria parva were cloned and sequenced. Neither of the genes is tandemly duplicated. One gene, TpABC1, encodes a predicted protein of 593 amino acids with an N-terminal hydrophobic domain containing six potential membrane-spanning segments. A single discontinuous ATP-binding element was located in the C-terminal region of TpABC1. The second gene, TpABC2, also contains a single C-terminal ATP-binding motif. Copies of TpABC2 were present at four loci in the T. parva genome on three different chromosomes. TpABC1 exhibited allelic polymorphism between stocks of the parasite. Comparison of cDNA and genomic sequences revealed that TpABC1 contained seven short introns, between 29 and 84 bp in length. The full-length TpABC1 protein was expressed in insect cells using the baculovirus system. Application of antibodies raised against the recombinant antigen to western blots of T. parva piroplasm lysates detected an 85 kDa protein in this life-cycle stage.

Low levels of graphene and graphene oxide inhibit cellular xenobiotic defense system mediated by efflux transporters.

PubMed

Liu, Su; Jiang, Wei; Wu, Bing; Yu, Jing; Yu, Haiyan; Zhang, Xu-Xiang; Torres-Duarte, Cristina; Cherr, Gary N

2016-01-01

Low levels of graphene and graphene oxide (GO) are considered to be environmentally safe. In this study, we analyzed the potential effects of graphene and GO at relatively low concentrations on cellular xenobiotic defense system mediated by efflux transporters. The results showed that graphene (<0.5 μg/mL) and GO (<20 μg/mL) did not decrease cell viability, generate reactive oxygen species, or disrupt mitochondrial function. However, graphene and GO at the nontoxic concentrations could increase calcein-AM (CAM, an indicator of membrane ATP-binding cassette (ABC) transporter) activity) accumulation, indicating inhibition of ABC transporters' efflux capabilities. This inhibition was observed even at 0.005 μg/mL graphene and 0.05 μg/mL GO, which are 100 times and 400 times lower than their lowest toxic concentration from cytotoxicity experiments, respectively. The inhibition of ABC transporters significantly increased the toxicity of paraquat and arsenic, known substrates of ABC transporters. The inhibition of ABC transporters was found to be based on graphene and GO damaging the plasma membrane structure and fluidity, thus altering functions of transmembrane ABC transporters. This study demonstrates that low levels of graphene and GO are not environmentally safe since they can significantly make cell more susceptible to other xenobiotics, and this chemosensitizing activity should be considered in the risk assessment of graphene and GO.

Multidrug resistance in parasites: ABC transporters, P-glycoproteins and molecular modelling.

PubMed

Jones, P M; George, A M

2005-04-30

Parasitic diseases, caused by protozoa, helminths and arthropods, rank among the most important problems in human and veterinary medicine, and in agriculture, leading to debilitating sicknesses and loss of life. In the absence of vaccines and with the general failure of vector eradication programs, drugs are the main line of defence, but the newest drugs are being tracked by the emergence of resistance in parasites, sharing ominous parallels with multidrug resistance in bacterial pathogens. Any of a number of mechanisms will elicit a drug resistance phenotype in parasites, including: active efflux, reduced uptake, target modification, drug modification, drug sequestration, by-pass shunting, or substrate competition. The role of ABC transporters in parasitic multidrug resistance mechanisms is being subjected to more scrutiny, due in part to the established roles of certain ABC transporters in human diseases, and also to an increasing portfolio of ABC transporters from parasite genome sequencing projects. For example, over 100 ABC transporters have been identified in the Escherichia coli genome, but to date only about 65 in all parasitic genomes. Long established laboratory investigations are now being assisted by molecular biology, bioinformatics, and computational modelling, and it is in these areas that the role of ABC transporters in parasitic multidrug resistance mechanisms may be defined and put in perspective with that of other proteins. We discuss ABC transporters in parasites, and conclude with an example of molecular modelling that identifies a new interaction between the structural domains of a parasite P-glycoprotein.

CD79B limits response of diffuse large B cell lymphoma to ibrutinib.

PubMed

Kim, Joo Hyun; Kim, Won Seog; Ryu, Kyungju; Kim, Seok Jin; Park, Chaehwa

2016-01-01

Blockage of B cell receptor signaling with ibrutinib presents a promising clinical approach for treatment of B-cell malignancies. However, many patients show primary resistance to the drug or develop secondary resistance. In the current study, cDNA microarray and Western blot analyses revealed CD79B upregulation in the activated B cell-like diffuse large B-cell lymphoma (ABC-DLBCL) that display differential resistance to ibrutinib. CD79B overexpression was sufficient to induce resistance to ibrutinib and enhanced AKT and MAPK activation, indicative of an alternative mechanism underlying resistance. Conversely, depletion of CD79B sensitized primary refractory cells to ibrutinib and led to reduced phosphorylation of AKT or MAPK. Combination of the AKT inhibitor or the MAPK inhibitor with ibrutinib resulted in circumvention of both primary and acquired resistance in ABC-DLBCL. Our data collectively indicate that CD79B overexpression leading to activation of AKT/MAPK is a potential mechanism underlying primary ibrutinib resistance in ABC-DLBCL, and support its utility as an effective biomarker to predict therapeutic response to ibrutinib.

Gene Expression in Single Cells Isolated from the CWR-R1 Prostate Cancer Cell Line and Human Prostate Tissue Based on the Side Population Phenotype.

PubMed

Gangavarapu, Kalyan J; Miller, Austin; Huss, Wendy J

2016-09-01

Defining biological signals at the single cell level can identify cancer initiating driver mutations. Techniques to isolate single cells such as microfluidics sorting and magnetic capturing systems have limitations such as: high cost, labor intense, and the requirement of a large number of cells. Therefore, the goal of our current study is to identify a cost and labor effective, reliable, and reproducible technique that allows single cell isolation for analysis to promote regular laboratory use, including standard reverse transcription PCR (RT-PCR). In the current study, we utilized single prostate cells isolated from the CWR-R1 prostate cancer cell line and human prostate clinical specimens, based on the ATP binding cassette (ABC) transporter efflux of dye cycle violet (DCV), side population assay. Expression of four genes: ABCG2; Aldehyde dehydrogenase1A1 (ALDH1A1); androgen receptor (AR); and embryonic stem cell marker, Oct-4, were determined. Results from the current study in the CWR-R1 cell line showed ABCG2 and ALDH1A1 gene expression in 67% of single side population cells and in 17% or 100% of non-side population cells respectively. Studies using single cells isolated from clinical specimens showed that the Oct-4 gene is detected in only 22% of single side population cells and in 78% of single non-side population cells. Whereas, AR gene expression is in 100% single side population and non-side population cells isolated from the same human prostate clinical specimen. These studies show that performing RT-PCR on single cells isolated by FACS can be successfully conducted to determine gene expression in single cells from cell lines and enzymatically digested tissue. While these studies provide a simple yes/no expression readout, the more sensitive quantitative RT-PCR would be able to provide even more information if necessary.

Gene Expression in Single Cells Isolated from the CWR-R1 Prostate Cancer Cell Line and Human Prostate Tissue Based on the Side Population Phenotype

PubMed Central

Gangavarapu, Kalyan J; Miller, Austin; Huss, Wendy J

2016-01-01

Defining biological signals at the single cell level can identify cancer initiating driver mutations. Techniques to isolate single cells such as microfluidics sorting and magnetic capturing systems have limitations such as: high cost, labor intense, and the requirement of a large number of cells. Therefore, the goal of our current study is to identify a cost and labor effective, reliable, and reproducible technique that allows single cell isolation for analysis to promote regular laboratory use, including standard reverse transcription PCR (RT-PCR). In the current study, we utilized single prostate cells isolated from the CWR-R1 prostate cancer cell line and human prostate clinical specimens, based on the ATP binding cassette (ABC) transporter efflux of dye cycle violet (DCV), side population assay. Expression of four genes: ABCG2; Aldehyde dehydrogenase1A1 (ALDH1A1); androgen receptor (AR); and embryonic stem cell marker, Oct-4, were determined. Results from the current study in the CWR-R1 cell line showed ABCG2 and ALDH1A1 gene expression in 67% of single side population cells and in 17% or 100% of non-side population cells respectively. Studies using single cells isolated from clinical specimens showed that the Oct-4 gene is detected in only 22% of single side population cells and in 78% of single non-side population cells. Whereas, AR gene expression is in 100% single side population and non-side population cells isolated from the same human prostate clinical specimen. These studies show that performing RT-PCR on single cells isolated by FACS can be successfully conducted to determine gene expression in single cells from cell lines and enzymatically digested tissue. While these studies provide a simple yes/no expression readout, the more sensitive quantitative RT-PCR would be able to provide even more information if necessary. PMID:27785389

A Graduate Management Project to Improve the Supplemental Care System at Walter Reed Army Medical Center

DTIC Science & Technology

1990-07-20

certain specified parameters. A method of establishing parameters for exceptions to the routine is called the ABC analysis of inventory control...Undcr ABC analysis, the A group is the 20% of line items which are most expensive per item, the B group is the next 20%, and the C group is the...part of a rational, orderly sytem which delivers the health care outputs required by the users, but allows the system managers to maintain control

Inactivation and deficiency of core proteins of photosystems I and II caused by genetical phylloquinone and plastoquinone deficiency but retained lamellar structure in a T-DNA mutant of Arabidopsis.

PubMed

Shimada, Hiroshi; Ohno, Ryoichi; Shibata, Masaru; Ikegami, Isamu; Onai, Kiyoshi; Ohto, Masa-aki; Takamiya, Ken-ichiro

2005-02-01

Phylloquinone, a substituted 1,4-naphthoquinone with an 18-carbon-saturated phytyl tail, functions as a bound one-electron carrier cofactor at the A1 site of photosystem I (PSI). A Feldmann tag line mutant, no. 2755 (designated as abc4 hereafter), showed pale-green young leaves and white old leaves. The mutated nuclear gene encoded 1,4-dihydroxy-2-naphtoic acid phytyltransferase, an enzyme of phylloquinone biosynthesis, and high-performance liquid chromatography analysis revealed that the abc4 mutant contained no phylloquinone, and only about 3% plastoquinone. Photooxidation of P700 of PSI in the abc4 mutant was not observed, and reduced-versus-oxidized difference spectroscopy indicated that the abc4 mutant had no P700. The maximum quantum yield of photosystem II (PSII) in the abc4 mutant was much decreased, and the electron transfer from PSII to PSI in the abc4 mutant did not occur. For the pale-green leaves of the abc4 mutant plant, the ultrastructure of the chloroplasts was almost the same as that of the wild-type plant. However, the chloroplasts in the albino leaves of the mutant were smaller and had a lot of grana thylakoids and few stroma thylakoids. The amounts of PSI and PSII core subunits in the abc4 mutant were significantly decreased compared with those in the wild type. These results suggested that a deficiency of phylloquinone in PSI caused the abolishment of PSI and a partial defect of PSII due to a significant decrease of plastoquinone, but did not influence the ultrastructure of the chloroplasts in young leaves.

Probing gas and dust in the tidal tail of NGC 5221 with the type Ia supernova iPTF16abc

NASA Astrophysics Data System (ADS)

Ferretti, R.; Amanullah, R.; Goobar, A.; Petrushevska, T.; Borthakur, S.; Bulla, M.; Fox, O.; Freeland, E.; Fremling, C.; Hangard, L.; Hayes, M.

2017-10-01

Context. Type Ia supernovae (SNe Ia) can be used to address numerous questions in astrophysics and cosmology. Due to their well known spectral and photometric properties, SNe Ia are well suited to study gas and dust along the lines-of-sight to the explosions. For example, narrow Na I D and Ca II H&K absorption lines can be studied easily, because of the well-defined spectral continuum of SNe Ia around these features. Aims: We aim to study the gas and dust along the line-of-sight to iPTF16abc, which occurred in an unusual location, in a tidal arm, 80 kpc from centre of the galaxy NGC 5221. Methods: Using a time-series of high-resolution spectra, we have examined narrow Na I D and Ca II H&K absorption features for variations in time, which would be indicative for circumstellar (CS) matter. Furthermore, we have taken advantage of the well known photometric properties of SNe Ia to determine reddening due to dust along the line-of-sight. Results: From the lack of variations in Na I D and Ca II H&K, we determine that none of the detected absorption features originate from the CS medium of iPTF16abc. While the Na I D and Ca II H&K absorption is found to be optically thick, a negligible amount of reddening points to a small column of interstellar dust. Conclusions: We find that the gas along the line-of-sight to iPTF16abc is typical of what might be found in the interstellar medium (ISM) within a galaxy. It suggests that we are observing gas that has been tidally stripped during an interaction of NGC 5221 with one of its neighbouring galaxies in the past 109 yr. In the future, the gas clouds could become the locations of star formation. On a longer time scale, the clouds might diffuse, enriching the circum-galactic medium (CGM) with metals. The gas profile along the line-of-sight should be useful for future studies of the dynamics of the galaxy group containing NGC 5221. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO DDT programme 297.D-5005(A), P. I. Ferretti.

Isolation and Applications of Prostate Side Population Cells Based on Dye Cycle Violet Efflux

PubMed Central

Gangavarapu, Kalyan J.; Huss, Wendy J.

2011-01-01

This unit describes methods for the digestion of human prostate clinical specimens, dye cycle violet (DCV) staining procedure for the identification, isolation, and quantitation of radiolabeled dihydrotestosterone (DHT) retention of side population cells. The principle of the side population assay is based on differential efflux of DCV, a cell membrane permeable fluorescent dye, by cells with high ATP binding cassette (ABC) transporter activity. Cells with high ABC transporter activity efflux DCV and fall in the lower left quadrant of a flow cytograph are designated as “side population” cells. This unit emphasizes tissue digestion, DCV staining, flow settings for sorting side population cells and quantitation of radiolabeled DHT retention. PMID:21400686

Repositioning of Tyrosine Kinase Inhibitors as Antagonists of ATP-Binding Cassette Transporters in Anticancer Drug Resistance

PubMed Central

Wang, Yi-Jun; Zhang, Yun-Kai; Kathawala, Rishil J.; Chen, Zhe-Sheng

2014-01-01

The phenomenon of multidrug resistance (MDR) has attenuated the efficacy of anticancer drugs and the possibility of successful cancer chemotherapy. ATP-binding cassette (ABC) transporters play an essential role in mediating MDR in cancer cells by increasing efflux of drugs from cancer cells, hence reducing the intracellular accumulation of chemotherapeutic drugs. Interestingly, small-molecule tyrosine kinase inhibitors (TKIs), such as AST1306, lapatinib, linsitinib, masitinib, motesanib, nilotinib, telatinib and WHI-P154, have been found to have the capability to overcome anticancer drug resistance by inhibiting ABC transporters in recent years. This review will focus on some of the latest and clinical developments with ABC transporters, TKIs and anticancer drug resistance. PMID:25268163

Mast Cells Produce a Unique Chondroitin Sulfate Epitope.

PubMed

Farrugia, Brooke L; Whitelock, John M; O'Grady, Robert; Caterson, Bruce; Lord, Megan S

2016-02-01

The granules of mast cells contain a myriad of mediators that are stored and protected by the sulfated glycosaminoglycan (GAG) chains that decorate proteoglycans. Whereas heparin is the GAG predominantly associated with mast cells, mast cell proteoglycans are also decorated with heparan sulfate and chondroitin sulfate (CS). This study investigated a unique CS structure produced by mast cells that was detected with the antibody clone 2B6 in the absence of chondroitinase ABC digestion. Mast cells in rodent tissue sections were characterized using toluidine blue, Leder stain and the presence of mast cell tryptase. The novel CS epitope was identified in rodent tissue sections and localized to cells that were morphologically similar to cells chemically identified as mast cells. The rodent mast cell-like line RBL-2H3 was also shown to express the novel CS epitope. This epitope co-localized with multiple CS proteoglycans in both rodent tissue and RBL-2H3 cultured cells. These findings suggest that the novel CS epitope that decorates mast cell proteoglycans may play a role in the way these chains are structured in mast cells. © 2016 The Histochemical Society.

Drug resistance-associated changes in sphingolipids and ABC transporters occur in different regions of membrane domains.

PubMed

Hinrichs, John W J; Klappe, Karin; van Riezen, Manon; Kok, Jan W

2005-11-01

We have recently shown that two ATP binding cassette (ABC) transporters are enriched in Lubrol-resistant noncaveolar membrane domains in multidrug-resistant human cancer cells [Hinrichs, J. W. J., K. Klappe, I. Hummel, and J. W. Kok. 2004. ATP-binding cassette transporters are enriched in non-caveolar detergent-insoluble glycosphingolipid-enriched membrane domains (DIGs) in human multidrug-resistant cancer cells. J. Biol. Chem. 279: 5734-5738]. Here, we show that aminophospholipids are relatively enriched in Lubrol-resistant membrane domains compared with Triton X-100-resistant membrane domains, whereas sphingolipids are relatively enriched in the latter. Moreover, Lubrol-resistant membrane domains contain more protein and lipid mass. Based on these results, we postulate a model for detergent-insoluble glycosphingolipid-enriched membrane domains consisting of a Lubrol-insoluble/Triton X-100-insoluble region and a Lubrol-insoluble/Triton X-100-soluble region. The latter region contains most of the ABC transporters as well as lipids known to be necessary for their efflux activity. Compared with drug-sensitive cells, the detergent-insoluble glycosphingolipid-enriched membrane domains (DIGs) in drug-resistant cells differ specifically in sphingolipid content and not in protein, phospholipid, or cholesterol content. In drug-resistant cells, sphingolipids with specific fatty acids (especially C24:1) are enriched in these membrane domains. Together, these data show that multidrug resistance-associated changes in both sphingolipids and ABC transporters occur in DIGs, but in different regions of these domains.

Antigen-binding cells in the peripheral blood of sockeye salmon, Oncorhynchus nerka Walbaum, induced by immersion or intraperitoneal injection of Vibrio languilarum bacterin

USGS Publications Warehouse

1981-01-01

We used an immunocytoadherence assay to monitor the response of antigen-binding cells (ABC) in the peripheral blood of sockeye salmon, Oncorhynchus nerka, after immersion in, or intraperitoneal injection of, Vibrio anguillarum LS 1–74 bacterin. Both methods initiated an elevated ABC response in less than one day; this response persisted one week longer in the injected than in the immersed fish.

UPregulated single-stranded DNA-binding protein 1 induces cell chemoresistance to cisplatin in lung cancer cell lines.

PubMed

Zhao, Xiang; He, Rong; Liu, Yu; Wu, Yongkai; Kang, Leitao

2017-07-01

Cisplatin and its analogues are widely used as anti-tumor drugs in lung cancer but many cisplatin-resistant lung cancer cases have been identified in recent years. Single-stranded DNA-binding protein 1 (SSDBP1) can effectively induce H69 cell resistance to cisplatin in our previous identification; thus, it is necessary to explore the mechanism underlying the effects of SSDBP1-induced resistance to cisplatin. First, SSDBP1-overexpressed or silent cell line was constructed and used to analyze the effects of SSDBP1 on chemoresistance of lung cancer cells to cisplatin. SSDBP1 expression was assayed by real-time PCR and Western blot. Next, the effects of SSDBP1 on cisplatin sensitivity, proliferation, and apoptosis of lung cancer cell lines were assayed by MTT and flow cytometry, respectively; ABC transporters, apoptosis-related genes, and cell cycle-related genes by real-time PCR, and DNA wound repair by comet assay. Low expression of SSDBP1 was observed in H69 cells, while increased expression in cisplatin-resistant H69 cells. Upregulated expression of SSDBP1 in H69AR cells was identified to promote proliferation and cisplatin resistance and inhibit apoptosis, while downregulation of SSDBP1 to inhibit cisplatin resistance and proliferation and promoted apoptosis. Moreover, SSDBP1 promoted the expression of P2gp, MRP1, Cyclin D1, and CDK4 and inhibited the expression of caspase 3 and caspase 9. Furthermore, SSDBP1 promoted the DNA wound repair. These results indicated that SSDBP1 may induce cell chemoresistance of cisplatin through promoting DNA repair, resistance-related gene expression, cell proliferation, and inhibiting apoptosis.

Patient-reported Quality of Life and Treatment Satisfaction in Patients With HR+/HER2- Advanced/Metastatic Breast Cancer.

PubMed

Wood, Robert; Mitra, Debanjali; de Courcy, Jonathan; Iyer, Shrividya

2017-08-01

Globally, around 1.67 million new cases of breast cancer are diagnosed each year, with advanced breast cancer (ABC-Stage III) and metastatic breast cancer (MBC-Stage IV) together accounting for up to 22% of incident cases. Hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR + /HER2 - ) breast cancer comprises 66% of ABC/MBC. Understanding disease-specific health-related quality of life and patient satisfaction with treatments currently available for HR + /HER2 - ABC/MBC in clinical practice is essential for assessing potential unmet need in this patient population. Data on treatment patterns in patients with HR + /HER2 - ABC/MBC were collected from oncology practices across the United States and Europe in a cross-sectional study in a clinical practice setting, the Adelphi Real World Advanced Breast Cancer Disease Specific Programme. A subset of patients included in the study completed several self-reported tools, including the Functional Assessment of Cancer Therapy-Breast and the Cancer Therapy Satisfaction Questionnaire. Analyses were conducted using data from the overall cohort and stratified by current treatment, metastatic sites, and number of prior therapy lines. Overall, 739 patients were recruited by 173 oncologists; 83% of patients had MBC, with the balance having ABC. The majority of patients with MBC had visceral metastases without bone metastases, and similar percentages of the total study population (≈40%) were receiving chemotherapy and endocrine therapy. Patients receiving only endocrine therapy had significantly better cancer-specific quality of life than did those receiving chemotherapy. Endocrine therapy also associated with fewer concerns about side effects and higher treatment satisfaction than chemotherapy. Statistically lower scores, indicating poorer well-being, were observed in patients with both bone and visceral metastases compared with those with either bone-only or visceral-only metastases for all but the Social/Family Well-Being and Functional Well-Being domains of the Functional Assessment of Cancer Therapy-Breast. Patients with bone and visceral metastases had significantly greater concerns about treatment side effects than those with metastases at other sites. Receipt of a greater number of prior lines of therapy was associated with poorer well-being scores. There was a significant negative association between number of lines of treatment and treatment expectations. Findings from this study from clinical practice suggest that treatment outcomes in HR + /HER2 - ABC/MBC could be optimized through improved understanding of the impact that components of patient care have on health-related quality of life and treatment satisfaction. Copyright © 2017 Elsevier HS Journals, Inc. All rights reserved.

Multidrug Resistance-Associated Protein 3 (Mrp3/Abcc3/Moat-D) Is Expressed in the SAE Squalus acanthias Shark Embryo–Derived Cell Line

PubMed Central

Kobayashi, Hiroshi; Parton, Angela; Czechanski, Anne; Durkin, Christopher; Kong, Chi-Chon; Barnes, David

2008-01-01

The multidrug resistance-associated protein 3 (MRP3/Mrp3) is a member of the ATP-binding cassette (ABC) protein family of membrane transporters and related proteins that act on a variety of xenobiotic and anionic molecules to transfer these substrates in an ATP-dependent manner. In recent years, useful comparative information regarding evolutionarily conserved structure and transport functions of these proteins has accrued through the use of primitive marine animals such as cartilaginous fish. Until recently, one missing tool in comparative studies with cartilaginous fish was cell culture. We have derived from the embryo of Squalus acanthias, the spiny dogfish shark, the S. acanthias embryo (SAE) mesenchymal stem cell line. This is the first continuously proliferating cell line from a cartilaginous fish. We identified expression of Mrp3 in this cell line, cloned the molecule, and examined molecular and cellular physiological aspects of the protein. Shark Mrp3 is characterized by three membrane-spanning domains and two nucleotide-binding domains. Multiple alignments with other species showed that the shark Mrp3 amino acid sequence was well conserved. The shark sequence was overall 64% identical to human MRP3, 72% identical to chicken Mrp3, and 71% identical to frog and stickleback Mrp3. Highest identity between shark and human amino acid sequence (82%) was seen in the carboxyl-terminal nucleotide-binding domain of the proteins. Cell culture experiments showed that mRNA for the protein was induced as much as 25-fold by peptide growth factors, fetal bovine serum, and lipid nutritional components, with the largest effect mediated by a combination of lipids including unsaturated and saturated fatty acids, cholesterol, and vitamin E. PMID:18284333

Multidrug resistance-associated protein 3 (Mrp3/Abcc3/Moat-D) is expressed in the SAE Squalus acanthias shark embryo-derived cell line.

PubMed

Kobayashi, Hiroshi; Parton, Angela; Czechanski, Anne; Durkin, Christopher; Kong, Chi-Chon; Barnes, David

2007-01-01

The multidrug resistance-associated protein 3 (MRP3/Mrp3) is a member of the ATP-binding cassette (ABC) protein family of membrane transporters and related proteins that act on a variety of xenobiotic and anionic molecules to transfer these substrates in an ATP-dependent manner. In recent years, useful comparative information regarding evolutionarily conserved structure and transport functions of these proteins has accrued through the use of primitive marine animals such as cartilaginous fish. Until recently, one missing tool in comparative studies with cartilaginous fish was cell culture. We have derived from the embryo of Squalus acanthias, the spiny dogfish shark, the S. acanthias embryo (SAE) mesenchymal stem cell line. This is the first continuously proliferating cell line from a cartilaginous fish. We identified expression of Mrp3 in this cell line, cloned the molecule, and examined molecular and cellular physiological aspects of the protein. Shark Mrp3 is characterized by three membrane-spanning domains and two nucleotide-binding domains. Multiple alignments with other species showed that the shark Mrp3 amino acid sequence was well conserved. The shark sequence was overall 64% identical to human MRP3, 72% identical to chicken Mrp3, and 71% identical to frog and stickleback Mrp3. Highest identity between shark and human amino acid sequence (82%) was seen in the carboxyl-terminal nucleotide-binding domain of the proteins. Cell culture experiments showed that mRNA for the protein was induced as much as 25-fold by peptide growth factors, fetal bovine serum, and lipid nutritional components, with the largest effect mediated by a combination of lipids including unsaturated and saturated fatty acids, cholesterol, and vitamin E.

NEMO Binding Domain peptide inhibits constitutive NF-κB activity and reduces tumor burden in a canine model of relapsed, refractory Diffuse Large B-Cell Lymphoma

PubMed Central

Gaurnier-Hausser, Anita; Patel, Reema; Baldwin, Albert S.; May, Michael J.; Mason, Nicola J.

2011-01-01

Purpose Activated B-Cell Diffuse Large B-Cell Lymphoma (ABC-DLBCL) is an aggressive, poorly chemoresponsive lymphoid malignancy characterized by constitutive canonical NF-κB activity that promotes lymphomagenesis and chemotherapy resistance via over-expression of anti-apoptotic NF-κB target genes. Inhibition of the canonical NF-κB pathway may therefore have therapeutic relevance in ABC-DLBCL. Here we set out to determine whether dogs with spontaneous DLBCL have comparative aberrant constitutive NF-κB activity and to determine the therapeutic relevance of NF-κB inhibition in dogs with relapsed, resistant DLBCL. Experimental Design Canonical NF-κB activity was evaluated by electrophoretic mobility shift assays and immunoblot analyses, and NF-κB target gene expression was measured by qRT-PCR. Primary malignant canine B lymphocytes were treated with the selective IKK complex inhibitor Nemo Binding Domain (NBD) peptide, and evaluated for NF-κB activity and apoptosis. NBD peptide was administered intra-nodally to dogs with relapsed B-cell lymphoma and NF-κB target gene expression and tumor burden were evaluated pre and post treatment. Results Constitutive canonical NF-κB activity and increased NF-κB target gene expression was detected in primary DLBCL tissue. NBD peptide inhibited this activity and induced apoptosis of primary malignant B cells in vitro. Intra-tumoral injections of NBD peptide to dogs with relapsed DLBCL inhibited NF-κB target gene expression and reduced tumor burden. Conclusions This work shows that dogs with spontaneous DLBCL represent a clinically relevant, spontaneous, large animal model for human ABC-DLBCL and demonstrates the therapeutic relevance of NF-κB inhibition in the treatment of ABC-DLBCL. These results have important translational relevance for ABC-DLBCL treatment in human patients. PMID:21610150

Design, Synthesis and Biological Evaluation of Novel Phosphorylated Abacavir Derivatives as Antiviral Agents Against Newcastle Disease Virus Infection in Chicken.

PubMed

K A, Suresh; Venkata Subbaiah, Kadiam C; Lavanya, Rayapu; Chandrasekhar, Kuruva; Chamarti, Naga Raju; Kumar, M Suresh; Wudayagiri, Rajendra; Valluru, Lokanatha

2016-09-01

Newcastle disease virus is the most devastating virus in poultry industry. It can eradicate the entire poultry flocks once infected. This study is aimed to investigate the antiviral efficacy of novel phosphorylated analogues of the drug abacavir (ABC) against Newcastle disease virus (NDV). About 16 analogues of ABC were designed and docking was performed against fusion protein of NDV. Three compounds were identified and selected for synthesis and biological evaluation based on binding affinity and docking scores. The compounds were synthesized and characterized by IR, (1)H, (13)C, (31)P and CHN analysis and mass spectra. These compounds were tested for antiviral efficacy against NDV-infected DF-1 cells. Compound ABC-1 had shown potent antiviral activity as evidenced by significant reduction in plaque units and cytopathic effect. Therefore, ABC-1 was selected to test for NDV-infected chicken survival rate. Effective dose50 concentrations were determined for ABC-1. Antioxidant enzyme levels in brain, liver and lung tissues were estimated. Superoxide dismutase and catalase were significantly raised and lipid peroxidation and HA titer levels were decreased upon treatment with 2 mg/kg body weight ABC-1. Histopathological modifications were also restored in the ABC-1-treated group. These findings demonstrated ABC-1 as a potential antiviral agent against NDV in chicken.

A bacterial-type ABC transporter is involved in aluminum tolerance in rice.

PubMed

Huang, Chao Feng; Yamaji, Naoki; Mitani, Namiki; Yano, Masahiro; Nagamura, Yoshiaki; Ma, Jian Feng

2009-02-01

Aluminum (Al) toxicity is a major factor limiting crop production in acidic soil, but the molecular mechanisms of Al tolerance are poorly understood. Here, we report that two genes, STAR1 (for sensitive to Al rhizotoxicity1) and STAR2, are responsible for Al tolerance in rice. STAR1 encodes a nucleotide binding domain, while STAR2 encodes a transmembrane domain, of a bacterial-type ATP binding cassette (ABC) transporter. Disruption of either gene resulted in hypersensitivity to aluminum toxicity. Both STAR1 and STAR2 are expressed mainly in the roots and are specifically induced by Al exposure. Expression in onion epidermal cells, rice protoplasts, and yeast showed that STAR1 interacts with STAR2 to form a complex that localizes to the vesicle membranes of all root cells, except for those in the epidermal layer of the mature zone. When expressed together in Xenopus laevis oocytes, STAR1/2 shows efflux transport activity specific for UDP-glucose. Furthermore, addition of exogenous UDP-glucose rescued root growth in the star1 mutant exposed to Al. These results indicate that STAR1 and STAR2 form a complex that functions as an ABC transporter, which is required for detoxification of Al in rice. The ABC transporter transports UDP-glucose, which may be used to modify the cell wall.

Comparison of a Rat Primary Cell-Based Blood-Brain Barrier Model With Epithelial and Brain Endothelial Cell Lines: Gene Expression and Drug Transport.

PubMed

Veszelka, Szilvia; Tóth, András; Walter, Fruzsina R; Tóth, Andrea E; Gróf, Ilona; Mészáros, Mária; Bocsik, Alexandra; Hellinger, Éva; Vastag, Monika; Rákhely, Gábor; Deli, Mária A

2018-01-01

Cell culture-based blood-brain barrier (BBB) models are useful tools for screening of CNS drug candidates. Cell sources for BBB models include primary brain endothelial cells or immortalized brain endothelial cell lines. Despite their well-known differences, epithelial cell lines are also used as surrogate models for testing neuropharmaceuticals. The aim of the present study was to compare the expression of selected BBB related genes including tight junction proteins, solute carriers (SLC), ABC transporters, metabolic enzymes and to describe the paracellular properties of nine different culture models. To establish a primary BBB model rat brain capillary endothelial cells were co-cultured with rat pericytes and astrocytes (EPA). As other BBB and surrogate models four brain endothelial cells lines, rat GP8 and RBE4 cells, and human hCMEC/D3 cells with or without lithium treatment (D3 and D3L), and four epithelial cell lines, native human intestinal Caco-2 and high P-glycoprotein expressing vinblastine-selected VB-Caco-2 cells, native MDCK and MDR1 transfected MDCK canine kidney cells were used. To test transporter functionality, the permeability of 12 molecules, glucopyranose, valproate, baclofen, gabapentin, probenecid, salicylate, rosuvastatin, pravastatin, atorvastatin, tacrine, donepezil, was also measured in the EPA and epithelial models. Among the junctional protein genes, the expression level of occludin was high in all models except the GP8 and RBE4 cells, and each model expressed a unique claudin pattern. Major BBB efflux (P-glycoprotein or ABCB1) and influx transporters (GLUT-1, LAT-1) were present in all models at mRNA levels. The transcript of BCRP (ABCG2) was not expressed in MDCK, GP8 and RBE4 cells. The absence of gene expression of important BBB efflux and influx transporters BCRP, MRP6, -9, MCT6, -8, PHT2, OATPs in one or both types of epithelial models suggests that Caco-2 or MDCK models are not suitable to test drug candidates which are substrates of these transporters. Brain endothelial cell lines GP8, RBE4, D3 and D3L did not form a restrictive paracellular barrier necessary for screening small molecular weight pharmacons. Therefore, among the tested culture models, the primary cell-based EPA model is suitable for the functional analysis of the BBB.

The ABC of BTC: structural properties and biological roles of betacellulin.

PubMed

Dahlhoff, Maik; Wolf, Eckhard; Schneider, Marlon R

2014-04-01

Betacellulin was initially detected as a growth-promoting factor in the conditioned medium of a mouse pancreatic β-cell tumor cell line. Sequencing of the purified protein and of the cloned cDNA supported the assumption that betacellulin is a new ligand of the epidermal growth factor receptor (EGFR), which was later confirmed experimentally. As a typical EGFR ligand, betacellulin is expressed by a variety of cell types and tissues, and the soluble growth factor is proteolytically cleaved from a larger membrane-anchored precursor. Importantly, BTC can - in addition to the EGFR - bind and activate all possible heterodimeric combinations of the related ERBB receptors including the highly oncogenic ERBB2/3 dimer, as well as homodimers of ERBB4. While a large number of studies attest a role for betacellulin in the differentiation of pancreatic β-cells, the last decade witnessed the association of betacellulin with a large number of additional biological processes, ranging from reproduction to the control of neural stem cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

Karanjin interferes with ABCB1, ABCC1, and ABCG2.

PubMed

Michaelis, Martin; Rothweiler, Florian; Nerreter, Thomas; Sharifi, Mohsen; Ghafourian, Taravat; Cinatl, Jindrich

2014-01-01

The prominent ATP-binding cassette (ABC) transporters ABCB1, ABCC1, and ABCG2 are involved in substance transport across physiological barriers and therefore in drug absorption, distribution, and elimination. They also mediate multi-drug resistance in cancer cells. Different flavonoids are known to interfere with different ABC transporters. Here, the effect of the furanoflavonol karanjin, a potential drug with antiglycaemic, gastroprotective, antifungal, and antibacterial effects, was investigated on ABCB1, ABCC1, and ABCG2-mediated drug transport in comparison to the flavonoids apigenin, genistein, and naringenin. Cells expressing the relevant transporters (ABCB1: UKF-NB-3(ABCB1), UKF-NB-3(r)VCR¹⁰; ABCC1: G62, PC-3(r)VCR²⁰; ABCG2: UKF-NB-3(ABCG2)) were used in combination with specific fluorescent and cytotoxic ABC transporter substrates and ABC transporter inhibitors to study ABC transporter function. Moreover, the effects of the investigated flavonoids were determined on the ABC transporter ATPase activities. Karanjin interfered with drug efflux mediated by ABCB1, ABCC1, and ABCG2 and enhanced the ATPase activity of all three transporters. Moreover, karanjin exerted more pronounced effects than the control flavonoids apigenin, genistein, and naringenin on all three transporters. Most notably, karanjin interfered with ABCB1 at low concentrations being about 1 µM. Taken together, these findings should be taken into account during further consideration of karanjin as a potential drug for different therapeutic indications. The effects on ABCB1, ABCC1, and ABCG2 may affect the pharmacokinetics of co-administered drugs.

Differential Adipose Tissue Gene Expression Profiles in Abacavir Treated Patients That May Contribute to the Understanding of Cardiovascular Risk: A Microarray Study

PubMed Central

Shahmanesh, Mohsen; Phillips, Kenneth; Boothby, Meg; Tomlinson, Jeremy W.

2015-01-01

Objective To compare changes in gene expression by microarray from subcutaneous adipose tissue from HIV treatment naïve patients treated with efavirenz based regimens containing abacavir (ABC), tenofovir (TDF) or zidovidine (AZT). Design Subcutaneous fat biopsies were obtained before, at 6- and 18–24-months after treatment, and from HIV negative controls. Groups were age, ethnicity, weight, biochemical profile, and pre-treatment CD4 count matched. Microarray data was generated using the Agilent Whole Human Genome Microarray. Identification of differentially expressed genes and genomic response pathways was performed using limma and gene set enrichment analysis. Results There were significant divergences between ABC and the other two groups 6 months after treatment in genes controlling cell adhesion and environmental information processing, with some convergence at 18–24 months. Compared to controls the ABC group, but not AZT or TDF showed enrichment of genes controlling adherence junction, at 6 months and 18–24 months (adjusted p<0.05) and focal adhesions and tight junction at 6 months (p<0.5). Genes controlling leukocyte transendothelial migration (p<0.05) and ECM-receptor interactions (p = 0.04) were over-expressed in ABC compared to TDF and AZT at 6 months but not at 18–24 months. Enrichment of pathways and individual genes controlling cell adhesion and environmental information processing were specifically dysregulated in the ABC group in comparison with other treatments. There was little difference between AZT and TDF. Conclusion After initiating treatment, there is divergence in the expression of genes controlling cell adhesion and environmental information processing between ABC and both TDF and AZT in subcutaneous adipose tissue. If similar changes are also taking place in other tissues including the coronary vasculature they may contribute to the increased risk of cardiovascular events reported in patients recently started on abacavir-containing regimens. PMID:25617630

IMG-ABC: An Atlas of Biosynthetic Gene Clusters to Fuel the Discovery of Novel Secondary Metabolites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, I-Min; Chu, Ken; Ratner, Anna

2014-10-28

In the discovery of secondary metabolites (SMs), large-scale analysis of sequence data is a promising exploration path that remains largely underutilized due to the lack of relevant computational resources. We present IMG-ABC (https://img.jgi.doe.gov/abc/) -- An Atlas of Biosynthetic gene Clusters within the Integrated Microbial Genomes (IMG) system1. IMG-ABC is a rich repository of both validated and predicted biosynthetic clusters (BCs) in cultured isolates, single-cells and metagenomes linked with the SM chemicals they produce and enhanced with focused analysis tools within IMG. The underlying scalable framework enables traversal of phylogenetic dark matter and chemical structure space -- serving as a doorwaymore » to a new era in the discovery of novel molecules.« less

[Biological characteristics of an enteroinvasive Escherichia coli strain with tatABC deletion].

PubMed

Gong, Zhaolong; Ye, Changyun; Liu, Xiaobing; Zhang, Min; Zhuo, Qin

2013-05-04

To study the relationship between twin-arginine translocation system (Tat) system with the biological characteristics of enteroinvasive Escherichia coli (EIEC). Through homologous recombination, we constructed EIEC's tatABC gene deletion strain and complementary strain, and explored their impact on bacterial form, substrate transport function as well as on HeLa cells and guinea pig's corneal invasion force. The tatABC gene deletion strain had apparent changes in bacterial form, loss of substrate transporter function, and significant weakened bacterial invasion force (the number of the deletion strain invading into HeLa cells was decreased significantly, and the ability of its corneal lesion capacity of the guinea pig was significantly weakened), while the complementary strain was similar to the wild strain in the above respects. EIEC's Tat protein transport system is closely related with the biological characteristics of EIEC.

Hypersensitivity Reaction Associated with Abacavir Therapy in an Indian HIV Patient - A Case Report.

PubMed

Janardhanan, Manju; Amberkar V, Mohan Babu; Vidyasagar, Sudha; Kumari K, Meena; Holla, Sadhana N

2014-09-01

The most important and unique adverse effect of abacavir (ABC) is fatal hypersensitivity reaction (HSR). The objective of this report is to describe a case of ABC induced HSR that occurred in an Indian HIV patient during treatment. Although this adverse effect is not uncommon, it is perhaps underreported or has never been reported so far in an Indian case scenario. A 44-year-old known case of HIV-1 was admitted in view of his worsening condition and very low CD4 cell counts 3 cells/μL. He was on anti-retroviral therapy since three years but not regular. On the basis of treatment failure, non-compliance and progressive low CD4 counts, the anti HIV regime was switched over to abacavir 600 mg+ atazanavir/ ritonavir 300mg/100mg Two weeks after ABC therapy he presented with maculopapular rash, headache and signs of hepatic damage (serum AST, ALP and ALT increased to 3-4 fold) suggestive of hypersensitivity reaction. As we know discontinuation of the drug is the ultimate litmus test to confirm diagnosis of drug induced adverse reaction. We did confirm ABC induced HSR by de-challenge wherein, rash disappeared within 2-3 days and LFT came back to normal within 5 days. However, no rechallenge was done. HSR was more in favour of ABC because atazanavir failed to produce any similar reaction after re-challenge.

NFκBP65 transcription factor modulates resistance to doxorubicin through ABC transporters in breast cancer.

PubMed

Velaei, Kobra; Samadi, Nasser; Soltani, Sina; Barazvan, Balal; Soleimani Rad, Jafar

2017-07-01

Shedding light on chemoresistance biology of breast cancer could contribute to enhance the clinical outcome. Intrinsic or acquired resistance to chemotherapy is a major problem in breast cancer treatment. The NFκB pathway by siRNAP65 and JSH-23 as a translocational inhibitor of NFκBP65 in the doxorubicin-resistant MCF-7 (MCF-7/Dox) and MCF-7 cells was blocked. Then, the ABC transporter expression and function were assessed by real-time qRT-PCR and flow cytometry, respectively. Induction of apoptosis was evaluated after inhibition of the NFΚB pathway as well. Our study underlined the upregulation of NFκBP65 and anti-apoptotic Bcl-2 and downregulation of pro-apoptotic Bax in the MCF-7/Dox cells compared with control MCF-7 cells. Here, we showed that interplay between nuclear factor kappa B P65 (NFkBP65) as a transcriptional regulator and ABC transporters in the MCF-7/Dox cancer cells. We found that inhibition of the elevated expression of NFκBP65 in the resistant breast cancer, whether translocational inhibition or silencing by siRNA, decreased the expression and function of MDR1 and MRP1 efflux pumps. Furthermore, the blockade of NFκBP65 promoted apoptosis via modulating Bcl-2 and BAX expression. After inhibition of the NFκBP65 signaling pathway, elevated baseline expression of survival Bcl-2 gene in the resistant breast cells significantly decreased. Suppression of the NFκB pathway has a profound dual impact on promoting the intrinsic apoptotic pathway and reducing ABC transporter function and expression, which are some of the chemoresistance features. It was speculated that the NFκB pathway directly acts on doxorubicin-induced MDR1 and MRP1 expression in MCF-7/Dox cells.

Dual Pathology of Mandible

PubMed Central

Rajurkar, Suday G.; Deshpande, Mohan D.; Kazi, Noaman; Jadhav, Dhanashree; Ranadive, Pallavi; Ingole, Snehal

2017-01-01

Aneurysmal Bone cyst (ABC)is a rare benign lesion of the bone which is infrequent in craniofacial region (12%). Rapid growth pattern causing bone expansion and facial asymmetry is a characteristic feature of ABC. Giant cell lesion is another distinct pathological entity. Here we present to you a rare case of dual pathology in an 11 year old female patient who presented with a large expansile lesion in the left hemimandible. All radiographic investigations were suggestive of ABC, aspiration of the lesion resulted in blood aspirate. However only after a histologic examination the dual nature of the lesion was revealed. PMID:29264307

Dual Pathology of Mandible.

PubMed

Rajurkar, Suday G; Deshpande, Mohan D; Kazi, Noaman; Jadhav, Dhanashree; Ranadive, Pallavi; Ingole, Snehal

2017-01-01

Aneurysmal Bone cyst (ABC)is a rare benign lesion of the bone which is infrequent in craniofacial region (12%). Rapid growth pattern causing bone expansion and facial asymmetry is a characteristic feature of ABC. Giant cell lesion is another distinct pathological entity. Here we present to you a rare case of dual pathology in an 11 year old female patient who presented with a large expansile lesion in the left hemimandible. All radiographic investigations were suggestive of ABC, aspiration of the lesion resulted in blood aspirate. However only after a histologic examination the dual nature of the lesion was revealed.

Montelukast is a potent and durable inhibitor of multidrug resistance protein 2 (MRP2)-mediated efflux of taxol and saquinavir

PubMed Central

Roy, Upal; Chakravarty, Geetika; Honer Zu Bentrup, Kerstin; Mondal, Debasis

2009-01-01

The ATP binding cassette (ABC)-transporters are energy dependent efflux pumps which regulate the pharmacokinetics of both anti-cancer chemotherapeutic agents, e.g. taxol, and of HIV-1 protease inhibitors (HPIs), e.g. saquinavir. Increased expression of several ABC-transporters, especially P-gp and MRP2, are observed in multidrug resistant (MDR) tumor cells and on HIV-1 infected lymphocytes. In addition, due to their apical expression on vascular endothelial barriers, both P-gp and MRP2 are of crucial importance towards dictating drug access into sequestered tissues. However, although a number of P-gp inhibitors are currently in clinical trials, possible inhibitors of MRP2 are not being thoroughly investigated. The experimental leukotriene receptor antagonist (LTRA), MK-571 is known to be a potent inhibitor of MRP transporters. Using the MRP2 over-expressing cell line, MDCKII-MRP2, we evaluated whether the clinically approved LTRAs, e.g. montelukast (Singulair™) and zafirlukast (Accolate™), can similarly suppress MRP2-mediated efflux. We compared the efficacy of increasing concentrations (20-100 μM) of MK-571, montelukast, and zafirlukast, in suppressing the efflux of calcein-AM, a fluorescent MRP substrate, and the radiolabeled [3H-] drugs, taxol and saquinavir. Montelukast was the most potent inhibitor (p<0.01) of MRP2-mediated efflux of all three substrates. Montelukast also increased (p<0.01) the duration of intracellular retention of both taxol and saquinavir. More than 50% of the drugs were retained in cells even after 90 mins post removal of montelukast from the medium. Our findings implicate that montelukast, a relatively safe anti-asthmatic agent, may be used as an adjunct therapy to suppress the efflux of taxol and saquinavir from MRP2 overexpressing cells. PMID:19952419

Neuronal glycosylation differentials in normal, injured and chondroitinase-treated environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kilcoyne, Michelle; Sharma, Shashank; McDevitt, Niamh

2012-04-13

Highlights: Black-Right-Pointing-Pointer Carbohydrates are important in the CNS and ChABC has been used for spinal cord injury (SCI) treatment. Black-Right-Pointing-Pointer Neuronal glycosylation in injury and after ChABC treatment is unknown. Black-Right-Pointing-Pointer In silico mining verified that glyco-related genes were differentially regulated after SCI. Black-Right-Pointing-Pointer In vitro model system revealed abnormal sialylation in an injured environment. Black-Right-Pointing-Pointer The model indicated a return to normal neuronal glycosylation after ChABC treatment. -- Abstract: Glycosylation is found ubiquitously throughout the central nervous system (CNS). Chondroitin sulphate proteoglycans (CSPGs) are a group of molecules heavily substituted with glycosaminoglycans (GAGs) and are found in the extracellularmore » matrix (ECM) and cell surfaces. Upon CNS injury, a glial scar is formed, which is inhibitory for axon regeneration. Several CSPGs are up-regulated within the glial scar, including NG2, and these CSPGs are key inhibitory molecules of axonal regeneration. Treatment with chondroitinase ABC (ChABC) can neutralise the inhibitory nature of NG2. A gene expression dataset was mined in silico to verify differentially regulated glycosylation-related genes in neurons after spinal cord injury and identify potential targets for further investigation. To establish the glycosylation differential of neurons that grow in a healthy, inhibitory and ChABC-treated environment, we established an indirect co-culture system where PC12 neurons were grown with primary astrocytes, Neu7 astrocytes (which overexpress NG2) and Neu7 astrocytes treated with ChABC. After 1, 4 and 8 days culture, lectin cytochemistry of the neurons was performed using five fluorescently-labelled lectins (ECA MAA, PNA, SNA-I and WFA). Usually {alpha}-(2,6)-linked sialylation scarcely occurs in the CNS but this motif was observed on the neurons in the injured environment only at day 8. Treatment with ChABC was successful in returning neuronal glycosylation to normal conditions at all timepoints for MAA, PNA and SNA-I staining, and by day 8 in the case of WFA. This study demonstrated neuronal cell surface glycosylation changes in an inhibitory environment and indicated a return to normal glycosylation after treatment with ChABC, which may be promising for identifying potential therapies for neuronal regeneration strategies.« less

Comparison of mechanistic transport cycle models of ABC exporters.

PubMed

Szöllősi, Dániel; Rose-Sperling, Dania; Hellmich, Ute A; Stockner, Thomas

2018-04-01

ABC (ATP binding cassette) transporters, ubiquitous in all kingdoms of life, carry out essential substrate transport reactions across cell membranes. Their transmembrane domains bind and translocate substrates and are connected to a pair of nucleotide binding domains, which bind and hydrolyze ATP to energize import or export of substrates. Over four decades of investigations into ABC transporters have revealed numerous details from atomic-level structural insights to their functional and physiological roles. Despite all these advances, a comprehensive understanding of the mechanistic principles of ABC transporter function remains elusive. The human multidrug resistance transporter ABCB1, also referred to as P-glycoprotein (P-gp), is one of the most intensively studied ABC exporters. Using ABCB1 as the reference point, we aim to compare the dominating mechanistic models of substrate transport and ATP hydrolysis for ABC exporters and to highlight the experimental and computational evidence in their support. In particular, we point out in silico studies that enhance and complement available biochemical data. "This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain." Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Searching for the fastest dynamo: laminar ABC flows.

PubMed

Alexakis, Alexandros

2011-08-01

The growth rate of the dynamo instability as a function of the magnetic Reynolds number R(M) is investigated by means of numerical simulations for the family of the Arnold-Beltrami-Childress (ABC) flows and for two different forcing scales. For the ABC flows that are driven at the largest available length scale, it is found that, as the magnetic Reynolds number is increased: (a) The flow that results first in a dynamo is the 2 1/2-dimensional flow for which A=B and C=0 (and all permutations). (b) The second type of flow that results in a dynamo is the one for which A=B≃2C/5 (and permutations). (c) The most symmetric flow, A=B=C, is the third type of flow that results in a dynamo. (d) As R(M) is increased, the A=B=C flow stops being a dynamo and transitions from a local maximum to a third-order saddle point. (e) At larger R(M), the A=B=C flow reestablishes itself as a dynamo but remains a saddle point. (f) At the largest examined R(M), the growth rate of the 2 1/2-dimensional flows starts to decay, the A=B=C flow comes close to a local maximum again, and the flow A=B≃2C/5 (and permutations) results in the fastest dynamo with growth rate γ≃0.12 at the largest examined R(M). For the ABC flows that are driven at the second largest available length scale, it is found that (a) the 2 1/2-dimensional flows A=B,C=0 (and permutations) are again the first flows that result in a dynamo with a decreased onset. (b) The most symmetric flow, A=B=C, is the second type of flow that results in a dynamo. It is, and it remains, a local maximum. (c) At larger R(M), the flow A=B≃2C/5 (and permutations) appears as the third type of flow that results in a dynamo. As R(M) is increased, it becomes the flow with the largest growth rate. The growth rates appear to have some correlation with the Lyapunov exponents, but constructive refolding of the field lines appears equally important in determining the fastest dynamo flow.

Trafficking and processing of bacterial proteins by mammalian cells: Insights from chondroitinase ABC.

PubMed

Muir, Elizabeth; Raza, Mansoor; Ellis, Clare; Burnside, Emily; Love, Fiona; Heller, Simon; Elliot, Matthew; Daniell, Esther; Dasgupta, Debayan; Alves, Nuno; Day, Priscilla; Fawcett, James; Keynes, Roger

2017-01-01

There is very little reported in the literature about the relationship between modifications of bacterial proteins and their secretion by mammalian cells that synthesize them. We previously reported that the secretion of the bacterial enzyme Chondroitinase ABC by mammalian cells requires the strategic removal of at least three N-glycosylation sites. The aim of this study was to determine if it is possible to enhance the efficacy of the enzyme as a treatment for spinal cord injury by increasing the quantity of enzyme secreted or by altering its cellular location. To determine if the efficiency of enzyme secretion could be further increased, cells were transfected with constructs encoding the gene for chondroitinase ABC modified for expression by mammalian cells; these contained additional modifications of strategic N-glycosylation sites or alternative signal sequences to direct secretion of the enzyme from the cells. We show that while removal of certain specific N-glycosylation sites enhances enzyme secretion, N-glycosylation of at least two other sites, N-856 and N-773, is essential for both production and secretion of active enzyme. Furthermore, we find that the signal sequence directing secretion also influences the quantity of enzyme secreted, and that this varies widely amongst the cell types tested. Last, we find that replacing the 3'UTR on the cDNA encoding Chondroitinase ABC with that of β-actin is sufficient to target the enzyme to the neuronal growth cone when transfected into neurons. This also enhances neurite outgrowth on an inhibitory substrate. Some intracellular trafficking pathways are adversely affected by cryptic signals present in the bacterial gene sequence, whilst unexpectedly others are required for efficient secretion of the enzyme. Furthermore, targeting chondroitinase to the neuronal growth cone promotes its ability to increase neurite outgrowth on an inhibitory substrate. These findings are timely in view of the renewed prospects for gene therapy, and of direct relevance to strategies aimed at expressing foreign proteins in mammalian cells, in particular bacterial proteins.

High-Affinity Vanadate Transport System in the Cyanobacterium Anabaena variabilis ATCC 29413

PubMed Central

Pratte, Brenda S.; Thiel, Teresa

2006-01-01

High-affinity vanadate transport systems have not heretofore been identified in any organism. Anabaena variabilis, which can fix nitrogen by using an alternative V-dependent nitrogenase, transported vanadate well. The concentration of vanadate giving half-maximum V-nitrogenase activity when added to V-starved cells was about 3 × 10−9 M. The genes for an ABC-type vanadate transport system, vupABC, were found in A. variabilis about 5 kb from the major cluster of genes encoding the V-nitrogenase, and like those genes, the vupABC genes were repressed by molybdate; however, unlike the V-nitrogenase genes the vanadate transport genes were expressed in vegetative cells. A vupB mutant failed to grow by using V-nitrogenase unless high levels of vanadate were provided, suggesting that there was also a low-affinity vanadate transport system that functioned in the vupB mutant. The vupABC genes belong to a family of putative metal transport genes that include only one other characterized transport system, the tungstate transport genes of Eubacterium acidaminophilum. Similar genes are not present in the complete genomes of other bacterial strains that have a V-nitrogenase, including Azotobacter vinelandii, Rhodopseudomonas palustris, and Methanosarcina barkeri. PMID:16385036

Anticancer copper(II) phosphorus dendrimers are potent proapoptotic Bax activators.

PubMed

Mignani, Serge; El Brahmi, Nabil; Eloy, Laure; Poupon, Joel; Nicolas, Valérie; Steinmetz, Anke; El Kazzouli, Said; Bousmina, Mosto M; Blanchard-Desce, Mireille; Caminade, Anne-Marie; Majoral, Jean-Pierre; Cresteil, Thierry

2017-05-26

A multivalent phosphorus dendrimer 1G 3 and its corresponding Cu-complex, 1G 3 -Cu have been recently identified as agents retaining high antiproliferative potency. This antiproliferative capacity was preserved in cell lines overexpressing the efflux pump ABC B1, whereas cross-resistance was observed in ovarian cancer cell lines resistant to cisplatin. Theoretical 3D models were constructed: the dendrimers appear as irregularly shaped disk-like nano-objects of about 22 Å thickness and 49 Å diameter, which accumulated in cells after penetration by endocytosis. To get insight in their mode of action, cell death pathways have been examined in human cancer cell lines: early apoptosis was followed by secondary necrosis after multivalent phosphorus dendrimers exposure. The multivalent plain phosphorus dendrimer 1G 3 moderately activated caspase-3 activity, in contrast with the multivalent Cu-conjugated phosphorus dendrimer 1G 3 -Cu which strikingly reduced the caspase-3 content and activity. This decrease of caspase activity is not related to the presence of copper, since inorganic copper has no or little effect on caspase-3. Conversely the potent apoptosis activation could be related to a noticeable translocation of Bax to the mitochondria, resulting in the release of AIF into the cytosol, its translocation to the nucleus and a severe DNA fragmentation, without alteration of the cell cycle. The multivalent Cu-conjugated phosphorus dendrimer is more efficient than its non-complexed analog to activate this pathway in close relationship with the higher antiproliferative potency. Therefore, this multivalent Cu-conjugated phosphorus dendrimer 1G 3 -Cu can be considered as a new and promising first-in-class antiproliferative agent with a distinctive mode of action, inducing apoptosis tumor cell death through Bax activation pathway. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

ABCA1, ABCG1 and SR-BI: hormonal regulation in primary rat hepatocytes and human cell lines

PubMed Central

Sporstøl, Marita; Mousavi, Seyed Ali; Eskild, Winnie; Roos, Norbert; Berg, Trond

2007-01-01

Background Scavenger receptor type B class I (SR-BI), ABC transporter A1 (ABCA1) -and G1 (ABCG1) all play important roles in the reverse cholesterol transport. Reverse cholesterol transport is a mechanism whereby the body can eliminate excess cholesterol. Here, the regulation of SR-BI, ABCA1, and ABCG1 by dexamethasone (a synthetic glucocorticoid) and insulin were studied in order to gain more insight into the role of these two hormones in the cholesterol metabolism. Results By use of real time RT-PCR and Western blotting we examined the expression of our target genes. The results show that SR-BI, ABCA1 and ABCG1 mRNA expression increased in response to dexamethasone while insulin treatment reduced the expression in primary rat hepatocytes. The stimulatory effect of dexamethasone was reduced by the addition of the anti-glucocorticoid mifepristone. In HepG2 cells and THP-1 macrophages, however, the effect of dexamethasone was absent or inhibitory with no significant change in the presence of mifepristone. The latter observation may be a result of the low protein expression of glucocorticoid receptor (GR) in these cell lines. Conclusion Our results illustrates that insulin and glucocorticoids, two hormones crucial in the carbohydrate metabolism, also play an important role in the regulation of genes central in reverse cholesterol transport. We found a marked difference in mRNA expression between the primary cells and the two established cell lines when studying the effect of dexamethasone which may result from the varying expression levels of GR. PMID:17241464

ABCA1, ABCG1 and SR-BI: hormonal regulation in primary rat hepatocytes and human cell lines.

PubMed

Sporstøl, Marita; Mousavi, Seyed Ali; Eskild, Winnie; Roos, Norbert; Berg, Trond

2007-01-22

Scavenger receptor type B class I (SR-BI), ABC transporter A1 (ABCA1) -and G1 (ABCG1) all play important roles in the reverse cholesterol transport. Reverse cholesterol transport is a mechanism whereby the body can eliminate excess cholesterol. Here, the regulation of SR-BI, ABCA1, and ABCG1 by dexamethasone (a synthetic glucocorticoid) and insulin were studied in order to gain more insight into the role of these two hormones in the cholesterol metabolism. By use of real time RT-PCR and Western blotting we examined the expression of our target genes. The results show that SR-BI, ABCA1 and ABCG1 mRNA expression increased in response to dexamethasone while insulin treatment reduced the expression in primary rat hepatocytes. The stimulatory effect of dexamethasone was reduced by the addition of the anti-glucocorticoid mifepristone. In HepG2 cells and THP-1 macrophages, however, the effect of dexamethasone was absent or inhibitory with no significant change in the presence of mifepristone. The latter observation may be a result of the low protein expression of glucocorticoid receptor (GR) in these cell lines. Our results illustrates that insulin and glucocorticoids, two hormones crucial in the carbohydrate metabolism, also play an important role in the regulation of genes central in reverse cholesterol transport. We found a marked difference in mRNA expression between the primary cells and the two established cell lines when studying the effect of dexamethasone which may result from the varying expression levels of GR.

Targeting the chromatin remodeling enzyme BRG1 increases the efficacy of chemotherapy drugs in breast cancer cells

PubMed Central

Wu, Qiong; Sharma, Soni; Cui, Hang; LeBlanc, Scott E.; Zhang, Hong; Muthuswami, Rohini; Nickerson, Jeffrey A.; Imbalzano, Anthony N.

2016-01-01

Brahma related gene product 1 (BRG1) is an ATPase that drives the catalytic activity of a subset of the mammalian SWI/SNF chromatin remodeling enzymes. BRG1 is overexpressed in most human breast cancer tumors without evidence of mutation and is required for breast cancer cell proliferation. We demonstrate that knockdown of BRG1 sensitized triple negative breast cancer cells to chemotherapeutic drugs used to treat breast cancer. An inhibitor of the BRG1 bromodomain had no effect on breast cancer cell viability, but an inhibitory molecule that targets the BRG1 ATPase activity recapitulated the increased drug efficacy observed in the presence of BRG1 knockdown. We further demonstrate that inhibition of BRG1 ATPase activity blocks the induction of ABC transporter genes by these chemotherapeutic drugs and that BRG1 binds to ABC transporter gene promoters. This inhibition increased intracellular concentrations of the drugs, providing a likely mechanism for the increased chemosensitivity. Since ABC transporters and their induction by chemotherapy drugs are a major cause of chemoresistance and treatment failure, these results support the idea that targeting the enzymatic activity of BRG1 would be an effective adjuvant therapy for breast cancer. PMID:27029062

A PhoPQ-Regulated ABC Transporter System Exports Tetracycline in Pseudomonas aeruginosa.

PubMed

Chen, Lin; Duan, Kangmin

2016-05-01

Pseudomonas aeruginosa is an important human pathogen whose infections are difficult to treat due to its high intrinsic resistance to many antibiotics. Here, we show that the disruption of PA4456, encoding the ATP binding component of a putative ATP-binding cassette (ABC) transporter, increased the bacterium's susceptible to tetracycline and other antibiotics or toxic chemicals. Fluorescence spectroscopy and antibiotic accumulation tests showed that the interruption of the ABC transporter caused increased intracellular accumulation of tetracycline, demonstrating a role of the ABC transporter in tetracycline expulsion. Site-directed mutagenesis proved that the conserved residues of E170 in the Walker B motif and H203 in the H-loop, which are important for ATP hydrolysis, were essential for the function of PA4456. Through a genome-wide search, the PhoPQ two-component system was identified as a regulator of the computationally predicted PA4456-4452 operon that encodes the ABC transporter system. A >5-fold increase of the expression of this operon was observed in the phoQ mutant. The results obtained also show that the expression of the phzA1B1C1D1E1 operon and the production of pyocyanin were significantly higher in the ABC transporter mutant, signifying a connection between the ABC transporter and pyocyanin production. These results indicated that the PhoPQ-regulated ABC transporter is associated with intrinsic resistance to antibiotics and other adverse compounds in P. aeruginosa, probably by extruding them out of the cell. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

The use of fluorescent indoline dyes for side population analysis.

PubMed

Kohara, Hiroshi; Watanabe, Kohei; Shintou, Taichi; Nomoto, Tsuyoshi; Okano, Mie; Shirai, Tomoaki; Miyazaki, Takeshi; Tabata, Yasuhiko

2013-01-01

Dye efflux assay evaluated by flow cytometry is useful for stem cell studies. The side population (SP) cells, characterized by the capacity to efflux Hoechst 33342 dye, have been shown to be enriched for hematopoietic stem cells (HSCs) in bone marrow. In addition, SP cells are isolated from various tissues and cell lines, and are also potential candidates for cancer stem cells. However, ultra violet (UV) light, which is not common for every flow cytometer, is required to excite Hoechst 33342. Here we showed that a fluorescent indoline dye ZMB793 can be excited by 488-nm laser, equipped in almost all the modern flow cytometers, and ZMB793-excluding cells showed SP phenotype. HSCs were exclusively enriched in the ZMB793-excluding cells, while ZMB793 was localized in cytosol of bone marrow lineage cells. The efflux of ZMB793 dye was mediated by ATP binding cassette (ABC) transporter Abcg2. Moreover, staining properties were affected by the side-chain structure of the dyes. These data indicate that the fluorescent dye ZMB793 could be used for the SP cell analysis. Copyright © 2012 Elsevier Ltd. All rights reserved.

Antibiotic Resistance Mediated by the MacB ABC Transporter Family: A Structural and Functional Perspective.

PubMed

Greene, Nicholas P; Kaplan, Elise; Crow, Allister; Koronakis, Vassilis

2018-01-01

The MacB ABC transporter forms a tripartite efflux pump with the MacA adaptor protein and TolC outer membrane exit duct to expel antibiotics and export virulence factors from Gram-negative bacteria. Here, we review recent structural and functional data on MacB and its homologs. MacB has a fold that is distinct from other structurally characterized ABC transporters and uses a unique molecular mechanism termed mechanotransmission. Unlike other bacterial ABC transporters, MacB does not transport substrates across the inner membrane in which it is based, but instead couples cytoplasmic ATP hydrolysis with transmembrane conformational changes that are used to perform work in the extra-cytoplasmic space. In the MacAB-TolC tripartite pump, mechanotransmission drives efflux of antibiotics and export of a protein toxin from the periplasmic space via the TolC exit duct. Homologous tripartite systems from pathogenic bacteria similarly export protein-like signaling molecules, virulence factors and siderophores. In addition, many MacB-like ABC transporters do not form tripartite pumps, but instead operate in diverse cellular processes including antibiotic sensing, cell division and lipoprotein trafficking.

Anti-CD22 and anti-CD79B antibody drug conjugates are active in different molecular diffuse large B-cell lymphoma subtypes.

PubMed

Pfeifer, M; Zheng, B; Erdmann, T; Koeppen, H; McCord, R; Grau, M; Staiger, A; Chai, A; Sandmann, T; Madle, H; Dörken, B; Chu, Y-W; Chen, A I; Lebovic, D; Salles, G A; Czuczman, M S; Palanca-Wessels, M C; Press, O W; Advani, R; Morschhauser, F; Cheson, B D; Lenz, P; Ott, G; Polson, A G; Mundt, K E; Lenz, G

2015-07-01

Antibody drug conjugates (ADCs), in which cytotoxic drugs are linked to antibodies targeting antigens on tumor cells, represent promising novel agents for the treatment of malignant lymphomas. Pinatuzumab vedotin is an anti-CD22 ADC and polatuzumab vedotin an anti-CD79B ADC that are both linked to the microtubule-disrupting agent monomethyl auristatin E (MMAE). In the present study, we analyzed the activity of these agents in different molecular subtypes of diffuse large B-cell lymphoma (DLBCL) both in vitro and in early clinical trials. Both anti-CD22-MMAE and anti-CD79B-MMAE were highly active and induced cell death in the vast majority of activated B-cell-like (ABC) and germinal center B-cell-like (GCB) DLBCL cell lines. Similarly, both agents induced cytotoxicity in models with and without mutations in the signaling molecule CD79B. In line with these observations, relapsed and refractory DLBCL patients of both subtypes responded to these agents. Importantly, a strong correlation between CD22 and CD79B expression in vitro and in vivo was not detectable, indicating that patients should not be excluded from anti-CD22-MMAE or anti-CD79B-MMAE treatment because of low target expression. In summary, these studies suggest that pinatuzumab vedotin and polatuzumab vedotin are active agents for the treatment of patients with different subtypes of DLBCL.

The ABC7 regimen: a new approach to metastatic breast cancer using seven common drugs to inhibit epithelial-to-mesenchymal transition and augment capecitabine efficacy.

PubMed

Kast, Richard E; Skuli, Nicolas; Cos, Samuel; Karpel-Massler, Georg; Shiozawa, Yusuke; Goshen, Ran; Halatsch, Marc-Eric

2017-01-01

Breast cancer metastatic to bone has a poor prognosis despite recent advances in our understanding of the biology of both bone and breast cancer. This article presents a new approach, the ABC7 regimen (Adjuvant for Breast Cancer treatment using seven repurposed drugs), to metastatic breast cancer. ABC7 aims to defeat aspects of epithelial-to-mesenchymal transition (EMT) that lead to dissemination of breast cancer to bone. As add-on to current standard treatment with capecitabine, ABC7 uses ancillary attributes of seven already-marketed noncancer treatment drugs to stop both the natural EMT process inherent to breast cancer and the added EMT occurring as a response to current treatment modalities. Chemotherapy, radiation, and surgery provoke EMT in cancer generally and in breast cancer specifically. ABC7 uses standard doses of capecitabine as used in treating breast cancer today. In addition, ABC7 uses 1) an older psychiatric drug, quetiapine, to block RANK signaling; 2) pirfenidone, an anti-fibrosis drug to block TGF-beta signaling; 3) rifabutin, an antibiotic to block beta-catenin signaling; 4) metformin, a first-line antidiabetic drug to stimulate AMPK and inhibit mammalian target of rapamycin, (mTOR); 5) propranolol, a beta-blocker to block beta-adrenergic signaling; 6) agomelatine, a melatonergic antidepressant to stimulate M1 and M2 melatonergic receptors; and 7) ribavirin, an antiviral drug to prevent eIF4E phosphorylation. All these block the signaling pathways - RANK, TGF-beta, mTOR, beta-adrenergic receptors, and phosphorylated eIF4E - that have been shown to trigger EMT and enhance breast cancer growth and so are worthwhile targets to inhibit. Agonism at MT1 and MT2 melatonergic receptors has been shown to inhibit both breast cancer EMT and growth. This ensemble was designed to be safe and augment capecitabine efficacy. Given the expected outcome of metastatic breast cancer as it stands today, ABC7 warrants a cautious trial.

ABC-F Proteins Mediate Antibiotic Resistance through Ribosomal Protection.

PubMed

Sharkey, Liam K R; Edwards, Thomas A; O'Neill, Alex J

2016-03-22

Members of the ABC-F subfamily of ATP-binding cassette proteins mediate resistance to a broad array of clinically important antibiotic classes that target the ribosome of Gram-positive pathogens. The mechanism by which these proteins act has been a subject of long-standing controversy, with two competing hypotheses each having gained considerable support: antibiotic efflux versus ribosomal protection. Here, we report on studies employing a combination of bacteriological and biochemical techniques to unravel the mechanism of resistance of these proteins, and provide several lines of evidence that together offer clear support to the ribosomal protection hypothesis. Of particular note, we show that addition of purified ABC-F proteins to anin vitrotranslation assay prompts dose-dependent rescue of translation, and demonstrate that such proteins are capable of displacing antibiotic from the ribosomein vitro To our knowledge, these experiments constitute the first direct evidence that ABC-F proteins mediate antibiotic resistance through ribosomal protection.IMPORTANCEAntimicrobial resistance ranks among the greatest threats currently facing human health. Elucidation of the mechanisms by which microorganisms resist the effect of antibiotics is central to understanding the biology of this phenomenon and has the potential to inform the development of new drugs capable of blocking or circumventing resistance. Members of the ABC-F family, which includelsa(A),msr(A),optr(A), andvga(A), collectively yield resistance to a broader range of clinically significant antibiotic classes than any other family of resistance determinants, although their mechanism of action has been controversial since their discovery 25 years ago. Here we present the first direct evidence that proteins of the ABC-F family act to protect the bacterial ribosome from antibiotic-mediated inhibition. Copyright © 2016 Sharkey et al.

Bloodstream infection caused by extensively drug-resistant Acinetobacter baumannii in cancer patients: high mortality associated with delayed treatment rather than with the degree of neutropenia.

PubMed

Freire, M P; de Oliveira Garcia, D; Garcia, C P; Campagnari Bueno, M F; Camargo, C H; Kono Magri, A S G; Francisco, G R; Reghini, R; Vieira, M F; Ibrahim, K Y; Rossi, F; Hajjar, L; Levin, A S; Hoff, P M; Pierrotti, L C; Abdala, E

2016-04-01

This study aimed to describe severe infections with extensively drug-resistant Acinetobacter baumannii-calcoaceticus complex (XDR-ABC), as well as to investigate risk factors for mortality, in cancer patients. It was a retrospective study including all patients diagnosed with XDR-ABC bacteraemia during hospitalization in the intensive care unit of a cancer hospital between July 2009 and July 2013. Surveillance cultures were collected weekly during the study period, and clonality was analysed using pulsed field gel electrophoresis (PFGE). We analysed underlying diseases, oncology therapy, neutrophil counts, infection site and management of infection, in terms of their correlation with 30-day mortality. During the study period, 92 patients with XDR-ABC bacteraemia were identified, of whom 35 (38.0%) were patients with haematological malignancy. We identified XDR-ABC strains with four different profile patterns, 91.3% of patients harbouring the predominant PFGE type. Of the 92 patients with XDR-ABC bacteraemia, 66 (71.7%) had central line-associated bloodstream infections; infection occurred during neutropenia in 22 (23.9%); and 58 (63.0%) died before receiving the appropriate therapy. All patients were treated with polymyxin, which was used in combination therapy in 30 of them (32.4%). The 30-day mortality rate was 83.7%. Multivariate analysis revealed that septic shock at diagnosis of XDR-ABC infection was a risk factor for 30-day mortality; protective factors were receiving appropriate therapy and invasive device removal within the first 48 h. Among cancer patients, ineffective management of such infection increases the risk of death, more so than do features such as neutropenia and infection at the tumour site. Copyright © 2015 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

A noticeable phenomenon: thiol terminal PEG enhances the immunogenicity of PEGylated emulsions injected intravenously or subcutaneously into rats.

PubMed

Wang, Chunling; Cheng, Xiaobo; Sui, Yue; Luo, Xiang; Jiang, Gongping; Wang, Yu; Huang, Zhenjun; She, Zhennan; Deng, Yihui

2013-11-01

Repeated intravenous injection of long-circulating methoxy-polyethylene glycol (PEG)-liposomes alters the pharmacokinetics and biodistribution of the second administration, regarded as the "accelerated blood clearance (ABC) phenomenon." Nevertheless, the effect of terminal groups of distearoylphosphatidylethanolamine-polyethylene glycol (DSPE-PEG) on the induction of the ABC phenomenon had not been reported previously. In this study, rats were injected intravenously or subcutaneously with PEG coated emulsions (DE) which were prepared using PEG terminated with either the methoxyl (OCH3), hydroxyl (OH), amino (NH2), carboxyl (COOH), or thiol (SH) group. DE-OCH3 demonstrated the longest prolonged half-life in vivo after a single intravenous injection, followed by DE-SH and DE-COOH. In contrast, DE-OH was rapidly removed from the blood circulation, as was DE-NH2. Moreover, we observed a strong positive relationship between the circulation time of initially injected PEGylated emulsions and the extent to which the ABC phenomenon was induced, but a exception of DE-SH increasing the ABC effect. Furthermore, the present study suggested that thiols might stimulate the proliferation and differentiation of B cells to induce the fastest clearance of the second intravenous administration by inducing the synthesis of the cell membrane and cytosolic proteins or reacting with follicular dendritic cells. The results strongly suggested that thiol groups played a stimulatory role in the immune response and provided a considerable implication for multiple drug therapy of thiol groups. Copyright © 2013 Elsevier B.V. All rights reserved.

Functional Dependence between Septal Protein SepJ from Anabaena sp. Strain PCC 7120 and an Amino Acid ABC-Type Uptake Transporter.

PubMed

Escudero, Leticia; Mariscal, Vicente; Flores, Enrique

2015-08-01

In the diazotrophic filaments of heterocyst-forming cyanobacteria, two different cell types, the CO2-fixing vegetative cells and the N2-fixing heterocysts, exchange nutrients, including some amino acids. In the model organism Anabaena sp. strain PCC 7120, the SepJ protein, composed of periplasmic and integral membrane (permease) sections, is located at the intercellular septa joining adjacent cells in the filament. The unicellular cyanobacterium Synechococcus elongatus strain PCC 7942 bears a gene, Synpcc7942_1024 (here designated dmeA), encoding a permease homologous to the SepJ permease domain. Synechococcus strains lacking dmeA or lacking dmeA and expressing Anabaena sepJ were constructed. The Synechococcus dmeA mutant showed a significant 22 to 32% decrease in the uptake of aspartate, glutamate, and glutamine, a phenotype that could be partially complemented by Anabaena sepJ. Synechococcus mutants of an ATP-binding-cassette (ABC)-type transporter for polar amino acids showed >98% decreased uptake of glutamate irrespective of the presence of dmeA or Anabaena sepJ in the same strain. Thus, Synechococcus DmeA or Anabaena SepJ is needed to observe full (or close to full) activity of the ABC transporter. An Anabaena sepJ deletion mutant was significantly impaired in glutamate and aspartate uptake, which also in this cyanobacterium requires the activity of an ABC-type transporter for polar amino acids. SepJ appears therefore to generally stimulate the activity of cyanobacterial ABC-type transporters for polar amino acids. Conversely, an Anabaena mutant of three ABC-type transporters for amino acids was impaired in the intercellular transfer of 5-carboxyfluorescein, a SepJ-related property. Our results unravel possible functional interactions in transport elements important for diazotrophic growth. Membrane transporters are essential for many aspects of cellular life, from uptake and export of substances in unicellular organisms to intercellular molecular exchange in multicellular organisms. Heterocyst-forming cyanobacteria such as Anabaena represent a unique case of multicellularity, in which two cell types exchange nutrients and regulators. The SepJ protein located at the intercellular septa in the filaments of Anabaena contains a permease domain of the drug/metabolite transporter (DMT) superfamily that somehow contributes to intercellular molecular transfer. In this work, we have found that SepJ stimulates the activity of a polar amino acid uptake transporter of the ATP-binding-cassette (ABC) superfamily, which could itself affect an intercellular transfer activity related to SepJ, thus unraveling possible functional interactions between these different transporters. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Upregulation of miR-124 by physcion 8-O-β-glucopyranoside inhibits proliferation and invasion of malignant melanoma cells via repressing RLIP76.

PubMed

Zhang, Di; Han, Yantao; Xu, Luo

2016-12-01

Melanoma is the most malignant type of skin cancer. In recent years, mounting studies have evidenced the involvement of miRNAs in melanoma. One of these miRNAs, miR-124 has been found aberrantly downregulated in a variety of human malignancies. In this study, our results showed that the expression of miR-124 was significantly lower in malignant melanoma tissues and cell lines and miR-124 functioned as a tumor suppressor in melanoma. Moreover, our findings showed that miR-124 exerted anti-tumor effect by directly targeting RLIP76, a stress-inducible non-ABC transporter that plays a crucial role in the development of melanoma. Furthermore, our study also showed that physcion 8-O-β-glucopyranoside, a natural compound from medicinal plant, could inhibit the proliferation and invasion of melanoma cells by targeting miR-124/RLIP76 signaling. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Translating the ABC-02 trial into daily practice: outcome of palliative treatment in patients with unresectable biliary tract cancer treated with gemcitabine and cisplatin.

PubMed

Dierks, J; Gaspersz, M P; Belkouz, A; van Vugt, J L A; Coelen, R J S; de Groot, J W B; Ten Tije, A J; Meijer, W G; Pruijt, J F M; van Voorthuizen, T; van Spronsen, D J; Rentinck, M; Ten Oever, D; Smit, J M; Otten, H M; van Gulik, T M; Wilmink, J W; Groot Koerkamp, B; Klümpen, H

2017-12-21

Biliary tract cancer (BTC) is an uncommon cancer with an unfavorable prognosis. Since 2010, the standard of care for patients with unresectable BTC is palliative treatment with gemcitabine plus cisplatin, based on the landmark phase III ABC-02 trial. This current study aims to evaluate the efficacy and safety of gemcitabine and cisplatin in patients with unresectable cholangiocarcinoma and gallbladder cancer in daily practice that meet the criteria for the ABC-02 trial in comparison to patients who did not. Patients diagnosed with unresectable BTC between 2010 and 2015 with an indication for gemcitabine and cisplatin were included. We divided these patients into three groups: (I) patients who received chemotherapy and met the criteria of the ABC-02 trial, (II) patients who received chemotherapy and did not meet these criteria and (III) patients who had an indication for chemotherapy, but received best supportive care without chemotherapy. Primary outcome was overall survival (OS) and secondary outcome was progression-free survival (PFS). We collected data of 208 patients, of which 138 (66.3%) patients received first line chemotherapy with gemcitabine and cisplatin. Median OS of 69 patients in group I, 63 patients in group II and 65 patients in group III was 9.6 months (95%CI = 6.7-12.5), 9.5 months (95%CI = 7.7-11.3) and 7.6 months (95%CI = 5.0-10.2), respectively. Median PFS was 6.0 months (95%CI = 4.4-7.6) in group I and 5.1 months (95%CI = 3.7-6.5) in group II. Toxicity and number of dose reductions (p = .974) were comparable between the two chemotherapy groups. First-line gemcitabine and cisplatin is an effective and safe treatment for patients with unresectable BTC who do not meet the eligibility criteria for the ABC-02 trial. Median OS, PFS and treatment side effects were comparable between the patients who received chemotherapy (group I vs. group II).

Surface charge-specific interactions between polymer nanoparticles and ABC transporters in Caco-2 cells

NASA Astrophysics Data System (ADS)

Bhattacharjee, Sourav; van Opstal, Edward J.; Alink, Gerrit M.; Marcelis, Antonius T. M.; Zuilhof, Han; Rietjens, Ivonne M. C. M.

2013-06-01

The surface charge-dependent transport of polymeric nanoparticles (PNPs) across Caco-2 monolayers grown on transwell culture systems as an in vitro model for intestinal transport was tested. The transport of well-characterized, monodisperse, and fluorescent tri-block copolymer nanoparticles (TCNPs/size 45 nm) and polystyrene nanoparticles (PSNPs/size 50 nm), with different surface charges (positive and negative), was quantified. The positive PNPs showed a higher intracellular uptake and flux across the Caco-2 monolayers than the negative PNPs. Multidrug resistance/P-glycoprotein (MDR1/P-gp), a specific ATP-binding cassette (ABC) transporter, was found to play a major role in the cellular efflux of positive PNPs, whereas the multidrug resistance protein 1 took part in the efflux of negative PNPs from Caco-2 cells. The positive PNPs also caused an increased cellular uptake and apical to basolateral transport of the carcinogen PhIP across the Caco-2 monolayer. The flavonoid quercetin, which is known to interact with ABC transporters, promoted the intracellular uptake of different PNPs and interfered with the normal distribution patterns of PNPs in the transwell system. These results indicate that PNPs display surface charge-specific interactions with ABC transporters and can even affect the bioavailability of toxic food-borne compounds (like pro-carcinogens).

CD34 expression in human hair follicles and tricholemmoma: a comprehensive study.

PubMed

Misago, Noriyuki; Toda, Shuji; Narisawa, Yutaka

2011-08-01

There has recently been controversy regarding whether clone My10 is superior to clone QBEND-10 for labeling cells of tricholemmal lineage. Moreover, there have been no previous reports on the CD34 expression in human vellus hair follicles. We performed a comprehensive study of the CD34 expression in human terminal and vellus hair follicles and in 10 tricholemmomas using both the QBEND-10 and the My10 clones. We also performed two different procedures of immunostaining, which included the using of the standard avidin-biotin-peroxidase (ABC) complex system and the Envision system. The most sensitive marker of CD34 for normal human hair follicles and tricholemmomas is QBEND-10 using the ABC system. The degree and strength of the CD34 positive staining mainly depended on the method being used (whether it was the ABC system or the Envision system) rather than the clone. CD34 staining was rarely (20-30%) seen in the anagen and catagen vellus hair follicles, and could only be seen by the QBEND-10 clone using the ABC system. CD34 expression in the tricholemmomas represented either a diffuse or peripheral pattern. CD34 may not be a tricholemmal lineage-specific antigen, but may be related to certain functions of the cells. Copyright © 2011 John Wiley & Sons A/S.

Molecular and functional characterization of FcγRIIIb receptor-ligand interaction: implications for neutrophil mediated immune mechanisms in malaria.

PubMed

Simtong, Piyapong; Romphruk, Amornrat V; Traum, Annalena; Burg-Roderfeld, Monika; Bein, Gregor; Jakubowski, Konstantin; Dominik, Andreas; Theisen, Michael; Kana, Ikhlaq Hussain; Sachs, Ulrich J; Santoso, Sentot

2018-05-21

The Fcγ receptor IIIb (FcγRIIIb) is a low-affinity receptor of IgG and is essential in neutrophil mediated effector functions. Different allelic forms of FcγRIIIb carrying human neutrophil antigen (HNA-1a, -1b, -1c and -1d) have been identified. Here, we have generated stable transfected HEK293 cell lines expressing HNA-1aa, -1bb, and -1bc. Of these, cells expressing HNA-1bc interacted significantly stronger (2.277 versus 0.743) with human IgG than cells expressing the HNA-1aa or -1bb alloforms. The higher affinity of IgG towards the HNA-1c alloform was confirmed using neutrophils derived from German blood donors. Neutrophils from HNA-1abc phenotyped individuals bound IgG significantly stronger (1.825 versus 0.903) than neutrophils from HNA-1ab typed individuals. These findings were confirmed by the SPR analysis demonstrating that recombinant HNA-1bc had a higher affinity (KD 7.24 x 10 -6 M) than recombinant HNA-1bb (KD 1.15 x 10 -5 M) against normal IgG. Finally, we demonstrated that Plasmodium falciparum merozoites opsonized with human IgG affinity purified against P. falciparum Glutamate rich protein (GLURP) enhanced stronger ROS emission in neutrophils obtained from HNA-1abc donors compared to neutrophils from HNA-1ab donors. Collectively, these results indicate that the amino acid substitution Ala 78 Asp resulting in the HNA-1c allotype leads to higher affinity towards human IgG, enhancement of neutrophil activation and possibly effective clearance of malaria by intracellular ROS. Copyright © 2018 American Society for Microbiology.

Energy gap formation mechanism through the interference phenomena of electrons in face-centered cubic elements and compounds with the emphasis on half-Heusler and Heusler compounds

NASA Astrophysics Data System (ADS)

Mizutani, U.; Sato, H.

2018-05-01

Many face-centred cubic elements and compounds with the number of atoms per unit cell N equal to 8, 12 and 16 are known to be stabilised by forming either a band gap or a pseudogap at the Fermi level. They are conveniently expressed as cF8, cF12 and cF16, respectively, in the Pearson symbol. From the cF8 family, we worked on three tetravalent elements C (diamond), Si and Ge, SZn-type AsGa compound and NaCl-type compounds like BiLu, AsSc, etc. From the cF12 family, more than 80 compounds were selected, with a particular emphasis on ABC- and half-Heusler-type ternary equiatomic compounds. Among cF16 compounds, both the Heusler compounds ABC2 and Zintl compounds were studied. We revealed that, regardless of whether or not the transition metal (TM) and/or rare-earth (RE) elements are involved as constituent elements, the energy gap formation mechanism for cF8, cF12 and cF16 compounds can be universally discussed in terms of interference phenomenon of itinerant electrons with set of reciprocal lattice planes with ? = 8, 11 and 12, where ? refers to square of the critical reciprocal of lattice vector of an fcc lattice. The number of itinerant electrons per unit cell, e/uc, for all these band gap/pseudogap-bearing compounds is found to fall on a universal line called "3/2-power law" when plotted against ? on a logarithmic scale. This proves the validity of the fulfilment of the interference condition ? in conformity with other pseudogap compounds with different crystal symmetries and different sizes of the unit cell reported in literature.

Amoeba-based computing for traveling salesman problem: long-term correlations between spatially separated individual cells of Physarum polycephalum.

PubMed

Zhu, Liping; Aono, Masashi; Kim, Song-Ju; Hara, Masahiko

2013-04-01

A single-celled, multi-nucleated amoeboid organism, a plasmodium of the true slime mold Physarum polycephalum, can perform sophisticated computing by exhibiting complex spatiotemporal oscillatory dynamics while deforming its amorphous body. We previously devised an "amoeba-based computer (ABC)" to quantitatively evaluate the optimization capability of the amoeboid organism in searching for a solution to the traveling salesman problem (TSP) under optical feedback control. In ABC, the organism changes its shape to find a high quality solution (a relatively shorter TSP route) by alternately expanding and contracting its pseudopod-like branches that exhibit local photoavoidance behavior. The quality of the solution serves as a measure of the optimality of which the organism maximizes its global body area (nutrient absorption) while minimizing the risk of being illuminated (exposure to aversive stimuli). ABC found a high quality solution for the 8-city TSP with a high probability. However, it remains unclear whether intracellular communication among the branches of the organism is essential for computing. In this study, we conducted a series of control experiments using two individual cells (two single-celled organisms) to perform parallel searches in the absence of intercellular communication. We found that ABC drastically lost its ability to find a solution when it used two independent individuals. However, interestingly, when two individuals were prepared by dividing one individual, they found a solution for a few tens of minutes. That is, the two divided individuals remained correlated even though they were spatially separated. These results suggest the presence of a long-term memory in the intrinsic dynamics of this organism and its significance in performing sophisticated computing. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Reproducibility of lung tumor position and reduction of lung mass within the planning target volume using active breathing control (ABC).

PubMed

Cheung, Patrick C F; Sixel, Katharina E; Tirona, Romeo; Ung, Yee C

2003-12-01

The active breathing control (ABC) device allows for temporary immobilization of respiratory motion by implementing a breath hold at a predefined relative lung volume and air flow direction. The purpose of this study was to quantitatively evaluate the ability of the ABC device to immobilize peripheral lung tumors at a reproducible position, increase total lung volume, and thereby reduce lung mass within the planning target volume (PTV). Ten patients with peripheral non-small-cell lung cancer tumors undergoing radiotherapy had CT scans of their thorax with and without ABC inspiration breath hold during the first 5 days of treatment. Total lung volumes were determined from the CT data sets. Each peripheral lung tumor was contoured by one physician on all CT scans to generate gross tumor volumes (GTVs). The lung density and mass contained within a 1.5-cm PTV margin around each peripheral tumor was calculated using CT numbers. Using the center of the GTV from the Day 1 ABC scan as the reference, the displacement of subsequent GTV centers on Days 2 to 5 for each patient with ABC applied was calculated in three dimensions. With the use of ABC inspiration breath hold, total lung volumes increased by an average of 42%. This resulted in an average decrease in lung mass of 18% within a standard 1.5-cm PTV margin around the GTV. The average (+/- standard deviation) displacement of GTV centers with ABC breath hold applied was 0.3 mm (+/- 1.8 mm), 1.2 mm (+/- 2.3 mm), and 1.1 mm (+/- 3.5 mm) in the lateral direction, anterior-posterior direction, and superior-inferior direction, respectively. Results from this study indicate that there remains some inter-breath hold variability in peripheral lung tumor position with the use of ABC inspiration breath hold, which prevents significant PTV margin reduction. However, lung volumes can significantly increase, thereby decreasing the mass of lung within a standard PTV.

The ABC transporter ABCG29 is involved in H2O2 tolerance and biocontrol traits in the fungus Clonostachys rosea.

PubMed

Dubey, Mukesh; Jensen, Dan Funck; Karlsson, Magnus

2016-04-01

For successful biocontrol interactions, biological control organisms must tolerate toxic metabolites produced by themselves or plant pathogens during mycoparasitic/antagonistic interactions, by host plant during colonization of the plant, and xenobiotics present in the environment. ATP-binding cassette (ABC) transporters can play a significant role in tolerance of toxic compounds by mediating active transport across the cellular membrane. This paper reports on functional characterization of an ABC transporter ABCG29 in the biocontrol fungus Clonostachys rosea strain IK726. Gene expression analysis showed induced expression of abcG29 during exposure to the Fusarium spp. mycotoxin zearalenone (ZEA) and the fungicides Cantus, Chipco Green and Apron. Expression of abcG29 in C. rosea was significantly higher during C. rosea-C. rosea (Cr-Cr) interaction or in exposure to C. rosea culture filtrate for 2 h, compared to interaction with Fusarium graminearum or 2 h exposure to F. graminearum culture filtrate. In contrast with gene expression data, ΔabcG29 strains did not display reduced tolerance towards ZEA, fungicides or chemical agents known for inducing oxidative, cell wall or osmotic stress, compared to C. rosea WT. The exception was a significant reduction in tolerance to H2O2 (10 mM) in ΔabcG29 strains when conidia were used as an inoculum. The antagonistic ability of ΔabcG29 strains towards F. graminearum, Fusarium oxysporum or Botrytis cinerea in dual plate assays were not different compared with WT. However, in biocontrol assays ΔabcG29 strains displayed reduced ability to protect Arabidopsis thaliana leaves from B. cinerea, and barley seedling from F. graminearum as measured by an A. thaliana detached leaf assay and a barley foot rot disease assay, respectively. These data show that the ABCG29 is dispensable for ZEA and fungicides tolerance, and antagonism but not H2O2 tolerance and biocontrol effects in C. rosea.

Mechanistic determinants of the directionality and energetics of active export by a heterodimeric ABC transporter

DOE PAGES

Grossmann, Nina; Vakkasoglu, Ahmet S.; Hulpke, Sabine; ...

2014-11-07

The ATP-binding cassette (ABC) transporter associated with antigen processing (TAP) participates in immune surveillance by moving proteasomal products into the endoplasmic reticulum (ER) lumen for major histocompatibility complex class I loading and cell surface presentation to cytotoxic T cells. Here we delineate the mechanistic basis for antigen translocation. Notably, TAP works as a molecular diode, translocating peptide substrates against the gradient in a strict unidirectional way. We reveal the importance of the D-loop at the dimer interface of the two nucleotide-binding domains (NBDs) in coupling substrate translocation with ATP hydrolysis and defining transport vectoriality. Substitution of the converved aspartate, whichmore » coordinates the ATP-binding site, decreases NBD dimerization affinity and turns the unidirectional primary active pump into a passive bidirectional nucleotide-gated facilitator. Thus, ATP hydrolysis is not required for translocation per se, but is essential for both active and unidirectional transport. As a result, our data provide detailed mechanistic insight into how heterodimeric ABC exporters operate.« less

Lymphomagenic CARD11/BCL10/MALT1 signaling drives malignant B-cell proliferation via cooperative NF-κB and JNK activation.

PubMed

Knies, Nathalie; Alankus, Begüm; Weilemann, Andre; Tzankov, Alexandar; Brunner, Kristina; Ruff, Tanja; Kremer, Marcus; Keller, Ulrich B; Lenz, Georg; Ruland, Jürgen

2015-12-29

The aggressive activated B cell-like subtype of diffuse large B-cell lymphoma is characterized by aberrant B-cell receptor (BCR) signaling and constitutive nuclear factor kappa-B (NF-κB) activation, which is required for tumor cell survival. BCR-induced NF-κB activation requires caspase recruitment domain-containing protein 11 (CARD11), and CARD11 gain-of-function mutations are recurrently detected in human diffuse large B-cell lymphoma (DLBCL). To investigate the consequences of dysregulated CARD11 signaling in vivo, we generated mice that conditionally express the human DLBCL-derived CARD11(L225LI) mutant. Surprisingly, CARD11(L225LI) was sufficient to trigger aggressive B-cell lymphoproliferation, leading to early postnatal lethality. CARD11(L225LI) constitutively associated with B-cell CLL/lymphoma 10 (BCL10) and mucosa-associated lymphoid tissue lymphoma translocation gene 1 (MALT1) to simultaneously activate the NF-κB and c-Jun N-terminal kinase (JNK) signaling cascades. Genetic deficiencies of either BCL10 or MALT1 completely rescued the phenotype, and pharmacological inhibition of JNK was, similar to NF-κB blockage, toxic to autonomously proliferating CARD11(L225LI)-expressing B cells. Moreover, constitutive JNK activity was observed in primary human activated B cell-like (ABC)-DLBCL specimens, and human ABC-DLBCL cells were also sensitive to JNK inhibitors. Thus, our results demonstrate that enforced activation of CARD11/BCL10/MALT1 signaling is sufficient to drive transformed B-cell expansion in vivo and identify the JNK pathway as a therapeutic target for ABC-DLBCL.

ATP Binding Cassette Transporter Mediates Both Heme and Pesticide Detoxification in Tick Midgut Cells

PubMed Central

Lara, Flavio Alves; Pohl, Paula C.; Gandara, Ana Caroline; Ferreira, Jessica da Silva; Nascimento-Silva, Maria Clara; Bechara, Gervásio Henrique; Sorgine, Marcos H. F.; Almeida, Igor C.; Vaz, Itabajara da Silva; Oliveira, Pedro L.

2015-01-01

In ticks, the digestion of blood occurs intracellularly and proteolytic digestion of hemoglobin takes place in a dedicated type of lysosome, the digest vesicle, followed by transfer of the heme moiety of hemoglobin to a specialized organelle that accumulates large heme aggregates, called hemosomes. In the present work, we studied the uptake of fluorescent metalloporphyrins, used as heme analogs, and amitraz, one of the most regularly used acaricides to control cattle tick infestations, by Rhipicephalus (Boophilus) microplus midgut cells. Both compounds were taken up by midgut cells in vitro and accumulated inside the hemosomes. Transport of both molecules was sensitive to cyclosporine A (CsA), a well-known inhibitor of ATP binding cassette (ABC) transporters. Rhodamine 123, a fluorescent probe that is also a recognized ABC substrate, was similarly directed to the hemosome in a CsA-sensitive manner. Using an antibody against conserved domain of PgP-1-type ABC transporter, we were able to immunolocalize PgP-1 in the digest vesicle membranes. Comparison between two R. microplus strains that were resistant and susceptible to amitraz revealed that the resistant strain detoxified both amitraz and Sn-Pp IX more efficiently than the susceptible strain, a process that was also sensitive to CsA. A transcript containing an ABC transporter signature exhibited 2.5-fold increased expression in the amitraz-resistant strain when compared with the susceptible strain. RNAi-induced down-regulation of this ABC transporter led to the accumulation of metalloporphyrin in the digestive vacuole, interrupting heme traffic to the hemosome. This evidence further confirms that this transcript codes for a heme transporter. This is the first report of heme transport in a blood-feeding organism. While the primary physiological function of the hemosome is to detoxify heme and attenuate its toxicity, we suggest that the use of this acaricide detoxification pathway by ticks may represent a new molecular mechanism of resistance to pesticides. PMID:26258982

Structure, function, and evolution of bacterial ATP-binding cassette systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davidson, A.L.; Dassa, E.; Orelle, C.

2010-07-27

The ATP-binding cassette (ABC) systems constitute one of the largest superfamilies of paralogous sequences. All ABC systems share a highly conserved ATP-hydrolyzing domain or protein (the ABC; also referred to as a nucleotide-binding domain [NBD]) that is unequivocally characterized by three short sequence motifs (Fig. 1): these are the Walker A and Walker B motifs, indicative of the presence of a nucleotide-binding site, and the signature motif, unique to ABC proteins, located upstream of the Walker B motif (426). Other motifs diagnostic of ABC proteins are also indicated in Fig. 1. The biological significance of these motifs is discussed inmore » Structure, Function, and Dynamics of the ABC. ABC systems are widespread among living organisms and have been detected in all genera of the three kingdoms of life, with remarkable conservation in the primary sequence of the cassette and in the organization of the constitutive domains or subunits (203, 420). ABC systems couple the energy of ATP hydrolysis to an impressively large variety of essential biological phenomena, comprising not only transmembrane (TM) transport, for which they are best known, but also several non-transport-related processes, such as translation elongation (62) and DNA repair (174). Although ABC systems deserve much attention because they are involved in severe human inherited diseases (107), they were first discovered and characterized in detail in prokaryotes, as early as the 1970s (13, 148, 238, 468). The most extensively analyzed systems were the high-affinity histidine and maltose uptake systems of Salmonella enterica serovar Typhimurium and Escherichia coli. Over 2 decades ago, after the completion of the nucleotide sequences encoding these transporters in the respective laboratories of Giovanna Ames and Maurice Hofnung, Hiroshi Nikaido and colleagues noticed that the two systems displayed a global similarity in the nature of their components and, moreover, that the primary sequences of MalK and HisP, the proteins suspected to energize these transporters, shared as much as 32% identity in amino acid residues when their sequences were aligned (171). Later, it was found that several bacterial proteins involved in uptake of nutrients, export of toxins, cell division, bacterial nodulation of plants, and DNA repair displayed the same similarity in their sequences (127, 196). This led to the notion that the conserved protein, which had been shown to bind ATP (198, 201), would probably energize the systems mentioned above by coupling the energy of ATP hydrolysis to transport. The latter was demonstrated with the maltose and histidine transporters by use of isolated membrane vesicles (105, 379) and purified transporters reconstituted into proteoliposomes (30, 98). The determination of the sequence of the first eukaryotic protein strongly similar to these bacterial transporters (the P-glycoprotein, involved in resistance of cancer cells to multiple drugs) (169, 179) demonstrated that these proteins were not restricted to prokaryotes. Two names, 'traffic ATPases' (15) and the more accepted name 'ABC transporters' (193, 218), were proposed for members of this new superfamily. ABC systems can be divided into three main functional categories, as follows. Importers mediate the uptake of nutrients in prokaryotes. The nature of the substrates that are transported is very wide, including mono- and oligosaccharides, organic and inorganic ions, amino acids, peptides, ironsiderophores, metals, polyamine cations, opines, and vitamins. Exporters are involved in the secretion of various molecules, such as peptides, lipids, hydrophobic drugs, polysaccharides, and proteins, including toxins such as hemolysin. The third category of systems is apparently not involved in transport, with some members being involved in translation of mRNA and in DNA repair. Despite the large, diverse population of substrates handled and the difference in the polarity of transport, importers and exporters share a common organization made of two hydrophobic membrane-spanning or integral membrane (IM) domains and two hydrophilic domains carrying the ABC peripherally associated with the IM domains on the cytosolic side of the membrane (26). In importers, these four domains are almost always independent polypeptide chains that come together to form a multimeric complex. In most exporters, including the E. coli hemolysin exporter HlyB, the N-terminal IM and the C-terminal ABC domains are fused as a single polypeptide chain (IM-ABC). An inverted organization in which the IM domain is C-terminal with respect to the ABC domain (ABC-IM) exists, such as in the MacB protein, involved in macrolide resistance in E. coli. No IM domain partners have been identified for ABC proteins falling into the third category, and these proteins consist of two ABCs fused together (ABC2).« less

Antibiotic Resistance Mediated by the MacB ABC Transporter Family: A Structural and Functional Perspective

PubMed Central

Greene, Nicholas P.; Kaplan, Elise; Crow, Allister; Koronakis, Vassilis

2018-01-01

The MacB ABC transporter forms a tripartite efflux pump with the MacA adaptor protein and TolC outer membrane exit duct to expel antibiotics and export virulence factors from Gram-negative bacteria. Here, we review recent structural and functional data on MacB and its homologs. MacB has a fold that is distinct from other structurally characterized ABC transporters and uses a unique molecular mechanism termed mechanotransmission. Unlike other bacterial ABC transporters, MacB does not transport substrates across the inner membrane in which it is based, but instead couples cytoplasmic ATP hydrolysis with transmembrane conformational changes that are used to perform work in the extra-cytoplasmic space. In the MacAB-TolC tripartite pump, mechanotransmission drives efflux of antibiotics and export of a protein toxin from the periplasmic space via the TolC exit duct. Homologous tripartite systems from pathogenic bacteria similarly export protein-like signaling molecules, virulence factors and siderophores. In addition, many MacB-like ABC transporters do not form tripartite pumps, but instead operate in diverse cellular processes including antibiotic sensing, cell division and lipoprotein trafficking. PMID:29892271

ABC transporters and immunity: mechanism of self-defense.

PubMed

Hinz, Andreas; Tampé, Robert

2012-06-26

The transporter associated with antigen processing (TAP) is a prototype of an asymmetric ATP-binding cassette (ABC) transporter, which uses ATP binding and hydrolysis to translocate peptides from the cytosol to the lumen of the endoplasmic reticulum (ER). Here, we review molecular details of peptide binding and ATP binding and hydrolysis as well as the resulting allosteric cross-talk between the nucleotide-binding domains and the transmembrane domains that drive translocation of the solute across the ER membrane. We also discuss the general molecular architecture of ABC transporters and demonstrate the importance of structural and functional studies for a better understanding of the role of the noncanonical site of asymmetric ABC transporters. Several aspects of peptide binding and specificity illustrate details of peptide translocation by TAP. Furthermore, this ABC transporter forms the central part of the major histocompatibility complex class I (MHC I) peptide-loading machinery. Hence, TAP is confronted with a number of viral factors, which prevent antigen translocation and MHC I loading in virally infected cells. We review how these viral factors have been used as molecular tools to decipher mechanistic aspects of solute translocation and discuss how they can help in the structural analysis of TAP.

The interaction of gut microbes with host ABC transporters

PubMed Central

Mercado-Lubo, Regino

2010-01-01

ATP binding cassette (ABC) transporters are increasingly recognized for their ability to modulate the absorption, distribution, metabolism, secretion and toxicity of xenobiotics. In addition to their essential function in drug resistance, there is also emerging evidence documenting the important role ABC transporters play in tissue defense. In this respect, the gastrointestinal tract represents a critical vanguard of defense against oral exposure of drugs while at the same time functions as a physical barrier between the lumenal contents (including bacteria) and the intestinal epithelium. Given emerging evidence suggesting that multidrug resistance protein (MDR) plays an important role in host-bacterial interactions in the gastrointestinal tract, this review will discuss the interplay between MDR of the intestinal epithelial cell barrier and gut microbes in health and disease. In particular, we will explore host-microbe interactions involving three apically restricted ABC transporters of the intestinal epithelium; P-glycoprotein (P-gp), multidrug resistance-associated protein 2 (MRP2) and cystic fibrosis transmembrane regulator (CFTR). PMID:21327038

Development and characterization of a long-acting nanoformulated abacavir prodrug.

PubMed

Singh, Dhirender; McMillan, JoEllyn; Hilaire, James; Gautam, Nagsen; Palandri, Diana; Alnouti, Yazen; Gendelman, Howard E; Edagwa, Benson

2016-08-01

A myristoylated abacavir (ABC) prodrug was synthesized to extend drug half-life and bioavailability. Myristoylated ABC (MABC) was made by esterifying myristic acid to the drug's 5-hydroxy-cyclopentene group. Chemical composition, antiretroviral activity, cell uptake and retention and cellular trafficking of free MABC and poloxamer nanoformulations of MABC were assessed by proton nuclear magnetic resonance and tested in human monocyte-derived macrophages. Pharmacokinetics of ABC and nanoformulated MABC were evaluated after intramuscular injection into mice. MABC antiretroviral activity in monocyte-derived macrophages was comparable to native drug. Encasement of MABC into poloxamer nanoparticles extended drug bioavailability for 2 weeks. MABC synthesis and encasement in polymeric nanoformulations improved intracellular drug accumulation and demonstrate translational potential as part of a long-acting antiretroviral regimen.

Conflict between Israel and Hamas

DTIC Science & Technology

2015-06-12

this plan, war erupted, leading to the free -for-all Arab land grab. The Egyptians usurped Gaza. The Jordanians occupied the West Bank. Then Israel took...102 Yaacov Amidror, “Line in the Sand ,” The BESA Center, February 2, 2015, accessed March 12, 2015, http://besacenter.org/?s=Line+in+the+ Sand . 69...Laub and Fares Akram, “Hamas Consolidates Its Grip on Gaza as Reconstruction Stalls Gaza City,” ABC News, accessed April 28, 2015, http

Conserved Allosteric Hot Spots in the Transmembrane Domains of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Channels and Multidrug Resistance Protein (MRP) Pumps*

PubMed Central

Wei, Shipeng; Roessler, Bryan C.; Chauvet, Sylvain; Guo, Jingyu; Hartman, John L.; Kirk, Kevin L.

2014-01-01

ATP-binding cassette (ABC) transporters are an ancient family of transmembrane proteins that utilize ATPase activity to move substrates across cell membranes. The ABCC subfamily of the ABC transporters includes active drug exporters (the multidrug resistance proteins (MRPs)) and a unique ATP-gated ion channel (cystic fibrosis transmembrane conductance regulator (CFTR)). The CFTR channel shares gating principles with conventional ligand-gated ion channels, but the allosteric network that couples ATP binding at its nucleotide binding domains (NBDs) with conformational changes in its transmembrane helices (TMs) is poorly defined. It is also unclear whether the mechanisms that govern CFTR gating are conserved with the thermodynamically distinct MRPs. Here we report a new class of gain of function (GOF) mutation of a conserved proline at the base of the pore-lining TM6. Multiple substitutions of this proline promoted ATP-free CFTR activity and activation by the weak agonist, 5′-adenylyl-β,γ-imidodiphosphate (AMP-PNP). TM6 proline mutations exhibited additive GOF effects when combined with a previously reported GOF mutation located in an outer collar of TMs that surrounds the pore-lining TMs. Each TM substitution allosterically rescued the ATP sensitivity of CFTR gating when introduced into an NBD mutant with defective ATP binding. Both classes of GOF mutations also rescued defective drug export by a yeast MRP (Yor1p) with ATP binding defects in its NBDs. We conclude that the conserved TM6 proline helps set the energy barrier to both CFTR channel opening and MRP-mediated drug efflux and that CFTR channels and MRP pumps utilize similar allosteric mechanisms for coupling conformational changes in their translocation pathways to ATP binding at their NBDs. PMID:24876383

Conserved allosteric hot spots in the transmembrane domains of cystic fibrosis transmembrane conductance regulator (CFTR) channels and multidrug resistance protein (MRP) pumps.

PubMed

Wei, Shipeng; Roessler, Bryan C; Chauvet, Sylvain; Guo, Jingyu; Hartman, John L; Kirk, Kevin L

2014-07-18

ATP-binding cassette (ABC) transporters are an ancient family of transmembrane proteins that utilize ATPase activity to move substrates across cell membranes. The ABCC subfamily of the ABC transporters includes active drug exporters (the multidrug resistance proteins (MRPs)) and a unique ATP-gated ion channel (cystic fibrosis transmembrane conductance regulator (CFTR)). The CFTR channel shares gating principles with conventional ligand-gated ion channels, but the allosteric network that couples ATP binding at its nucleotide binding domains (NBDs) with conformational changes in its transmembrane helices (TMs) is poorly defined. It is also unclear whether the mechanisms that govern CFTR gating are conserved with the thermodynamically distinct MRPs. Here we report a new class of gain of function (GOF) mutation of a conserved proline at the base of the pore-lining TM6. Multiple substitutions of this proline promoted ATP-free CFTR activity and activation by the weak agonist, 5'-adenylyl-β,γ-imidodiphosphate (AMP-PNP). TM6 proline mutations exhibited additive GOF effects when combined with a previously reported GOF mutation located in an outer collar of TMs that surrounds the pore-lining TMs. Each TM substitution allosterically rescued the ATP sensitivity of CFTR gating when introduced into an NBD mutant with defective ATP binding. Both classes of GOF mutations also rescued defective drug export by a yeast MRP (Yor1p) with ATP binding defects in its NBDs. We conclude that the conserved TM6 proline helps set the energy barrier to both CFTR channel opening and MRP-mediated drug efflux and that CFTR channels and MRP pumps utilize similar allosteric mechanisms for coupling conformational changes in their translocation pathways to ATP binding at their NBDs. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

A chondroitinase-ABC and TGF-β1 treatment regimen for enhancing the mechanical properties of tissue-engineered fibrocartilage.

PubMed

MacBarb, Regina F; Makris, Eleftherios A; Hu, Jerry C; Athanasiou, Kyriacos A

2013-01-01

The development of functionally equivalent fibrocartilage remains elusive despite efforts to engineer tissues such as knee meniscus, intervertebral disc and temporomandibular joint disc. Attempts to engineer these structures often fail to create tissues with mechanical properties on a par with native tissue, resulting in constructs unsuitable for clinical applications. The objective of this study was to engineer a spectrum of biomimetic fibrocartilages representative of the distinct functional properties found in native tissues. Using the self-assembly process, different co-cultures of meniscus cells and articular chondrocytes were seeded into agarose wells and treated with the catabolic agent chondroitinase-ABC (C-ABC) and the anabolic agent transforming growth factor-β1 (TGF-β1) via a two-factor (cell ratio and bioactive treatment), full factorial study design. Application of both C-ABC and TGF-β1 resulted in a beneficial or positive increase in the collagen content of treated constructs compared to controls. Significant increases in both the collagen density and fiber diameter were also seen with this treatment, increasing these values by 32 and 15%, respectively, over control values. Mechanical testing found the combined bioactive treatment to synergistically increase the Young's modulus and ultimate tensile strength of the engineered fibrocartilages compared to controls, with values reaching the lower spectrum of those found in native tissues. Together, these data demonstrate that C-ABC and TGF-β1 interact to develop a denser collagen matrix better able to withstand tensile loading. This study highlights a way to optimize the tensile properties of engineered fibrocartilage using a biochemical and a biophysical agent together to create distinct fibrocartilages with functional properties mimicking those of native tissue. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

A chondroitinase-ABC and TGF-β1 treatment regimen for enhancing the mechanical properties of tissue engineered fibrocartilage

PubMed Central

MacBarb, Regina F.; Makris, Eleftherios A.; Hu, Jerry C.; Athanasiou, Kyriacos A.

2012-01-01

The development of functionally equivalent fibrocartilage remains elusive despite efforts to engineer tissues such as the knee menisci, intervertebral disc, and TMJ disc. Attempts to engineer these structures often fail to create tissues with mechanical properties on par with native tissue, resulting in constructs unsuitable for clinical applications. The objective of this study was to engineer a spectrum of biomimetic fibrocartilages representative of the distinct functional properties found in native tissues. Using the self-assembly process, different co-cultures of meniscus cells (MCs) and articular chondrocytes (ACs) were seeded into agarose wells and treated with the catabolic agent chondroitinase-ABC (C-ABC) and the anabolic agent transforming growth factor-β1 (TGF-β1) via a two-factor (cell ratio and bioactive treatment), full factorial study design. Application of both C-ABC and TGF-β1 resulted in a beneficial or positive increase in the collagen content of treated constructs compared to controls. Significant increases in both the collagen density and fiber diameter were also seen with this treatment, increasing these values 32% and 15%, respectively, over control values. Mechanical testing found the combined bioactive treatment to synergistically increase the Young’s modulus and ultimate tensile strength of the engineered fibrocartilages compared to controls, with values reaching the lower spectrum of those found in native tissues. Together, these data demonstrate that C-ABC and TGF-β1 interact to develop a denser collagen matrix better able to withstand tensile loading. This study highlights a way to optimize the tensile properties of engineered fibrocartilage using a biochemical and biophysical agent together to create distinct fibrocartilages with functional properties mimicking those of native tissue. PMID:23041782

Background staining of visualization systems in immunohistochemistry: comparison of the Avidin-Biotin Complex system and the EnVision+ system.

PubMed

Vosse, Bettine A H; Seelentag, Walter; Bachmann, Astrid; Bosman, Fred T; Yan, Pu

2007-03-01

The aim of this study was to evaluate specific immunostaining and background staining in formalin-fixed, paraffin-embedded human tissues with the 2 most frequently used immunohistochemical detection systems, Avidin-Biotin-Peroxidase (ABC) and EnVision+. A series of fixed tissues, including breast, colon, kidney, larynx, liver, lung, ovary, pancreas, prostate, stomach, and tonsil, was used in the study. Three monoclonal antibodies, 1 against a nuclear antigen (Ki-67), 1 against a cytoplasmic antigen (cytokeratin), and 1 against a cytoplasmic and membrane-associated antigen and a polyclonal antibody against a nuclear and cytoplasmic antigen (S-100) were selected for these studies. When the ABC system was applied, immunostaining was performed with and without blocking of endogenous avidin-binding activity. The intensity of specific immunostaining and the percentage of stained cells were comparable for the 2 detection systems. The use of ABC caused widespread cytoplasmic and rare nuclear background staining in a variety of normal and tumor cells. A very strong background staining was observed in colon, gastric mucosa, liver, and kidney. Blocking avidin-binding capacity reduced background staining, but complete blocking was difficult to attain. With the EnVision+ system no background staining occurred. Given the efficiency of the detection, equal for both systems or higher with EnVision+, and the significant background problem with ABC, we advocate the routine use of the EnVision+ system.

Melanoma Cell Colony Expansion Parameters Revealed by Approximate Bayesian Computation

PubMed Central

Vo, Brenda N.; Drovandi, Christopher C.; Pettitt, Anthony N.; Pettet, Graeme J.

2015-01-01

In vitro studies and mathematical models are now being widely used to study the underlying mechanisms driving the expansion of cell colonies. This can improve our understanding of cancer formation and progression. Although much progress has been made in terms of developing and analysing mathematical models, far less progress has been made in terms of understanding how to estimate model parameters using experimental in vitro image-based data. To address this issue, a new approximate Bayesian computation (ABC) algorithm is proposed to estimate key parameters governing the expansion of melanoma cell (MM127) colonies, including cell diffusivity, D, cell proliferation rate, λ, and cell-to-cell adhesion, q, in two experimental scenarios, namely with and without a chemical treatment to suppress cell proliferation. Even when little prior biological knowledge about the parameters is assumed, all parameters are precisely inferred with a small posterior coefficient of variation, approximately 2–12%. The ABC analyses reveal that the posterior distributions of D and q depend on the experimental elapsed time, whereas the posterior distribution of λ does not. The posterior mean values of D and q are in the ranges 226–268 µm2h−1, 311–351 µm2h−1 and 0.23–0.39, 0.32–0.61 for the experimental periods of 0–24 h and 24–48 h, respectively. Furthermore, we found that the posterior distribution of q also depends on the initial cell density, whereas the posterior distributions of D and λ do not. The ABC approach also enables information from the two experiments to be combined, resulting in greater precision for all estimates of D and λ. PMID:26642072

The ABC7 regimen: a new approach to metastatic breast cancer using seven common drugs to inhibit epithelial-to-mesenchymal transition and augment capecitabine efficacy

PubMed Central

Kast, Richard E; Skuli, Nicolas; Cos, Samuel; Karpel-Massler, Georg; Shiozawa, Yusuke; Goshen, Ran; Halatsch, Marc-Eric

2017-01-01

Breast cancer metastatic to bone has a poor prognosis despite recent advances in our understanding of the biology of both bone and breast cancer. This article presents a new approach, the ABC7 regimen (Adjuvant for Breast Cancer treatment using seven repurposed drugs), to metastatic breast cancer. ABC7 aims to defeat aspects of epithelial-to-mesenchymal transition (EMT) that lead to dissemination of breast cancer to bone. As add-on to current standard treatment with capecitabine, ABC7 uses ancillary attributes of seven already-marketed noncancer treatment drugs to stop both the natural EMT process inherent to breast cancer and the added EMT occurring as a response to current treatment modalities. Chemotherapy, radiation, and surgery provoke EMT in cancer generally and in breast cancer specifically. ABC7 uses standard doses of capecitabine as used in treating breast cancer today. In addition, ABC7 uses 1) an older psychiatric drug, quetiapine, to block RANK signaling; 2) pirfenidone, an anti-fibrosis drug to block TGF-beta signaling; 3) rifabutin, an antibiotic to block beta-catenin signaling; 4) metformin, a first-line antidiabetic drug to stimulate AMPK and inhibit mammalian target of rapamycin, (mTOR); 5) propranolol, a beta-blocker to block beta-adrenergic signaling; 6) agomelatine, a melatonergic antidepressant to stimulate M1 and M2 melatonergic receptors; and 7) ribavirin, an antiviral drug to prevent eIF4E phosphorylation. All these block the signaling pathways – RANK, TGF-beta, mTOR, beta-adrenergic receptors, and phosphorylated eIF4E – that have been shown to trigger EMT and enhance breast cancer growth and so are worthwhile targets to inhibit. Agonism at MT1 and MT2 melatonergic receptors has been shown to inhibit both breast cancer EMT and growth. This ensemble was designed to be safe and augment capecitabine efficacy. Given the expected outcome of metastatic breast cancer as it stands today, ABC7 warrants a cautious trial. PMID:28744157

Recent Abacavir Use Increases Risk of Type 1 and Type 2 Myocardial Infarctions Among Adults With HIV.

PubMed

Elion, Richard A; Althoff, Keri N; Zhang, Jinbing; Moore, Richard D; Gange, Stephen J; Kitahata, Mari M; Crane, Heidi M; Drozd, Daniel R; Stein, James H; Klein, Marina B; Eron, Joseph J; Silverberg, Michael J; Mathews, William C; Justice, Amy C; Sterling, Timothy R; Rabkin, Charles S; Mayor, Angel M; Klein, Daniel B; Horberg, Michael A; Bosch, Ronald J; Eyawo, Oghenowede; Palella, Frank J

2018-05-01

There is persistent confusion as to whether abacavir (ABC) increases the risk of myocardial infarction (MI), and whether such risk differs by type 1 (T1MI) or 2 (T2MI) MI in adults with HIV. Incident MIs in North American Cohort Collaboration on Research and Design participants were identified from 2001 to 2013. Discrete time marginal structural models addressed channeling biases and time-dependent confounding to estimate crude hazard ratio (HR) and adjusted hazard ratio (aHR) and 95% confidence intervals; analyses were performed for T1MI and T2MI separately. A sensitivity analysis evaluated whether Framingham risk score (FRS) modified the effect of ABC on MI occurrence. Eight thousand two hundred sixty-five adults who initiated antiretroviral therapy contributed 29,077 person-years and 123 MI events (65 T1MI and 58 T2MI). Median follow-up time was 2.9 (interquartile range 1.4-5.1) years. ABC initiators were more likely to have a history of injection drug use, hepatitis C virus infection, hypertension, diabetes, impaired kidney function, hyperlipidemia, low (<200 cells/mm) CD4 counts, and a history of AIDS. The risk of the combined MI outcome was greater for persons who used ABC in the previous 6 months [aHR = 1.84 (1.17-2.91)]; and persisted for T1MI (aHR = 1.62 [1.01]) and T2MI [aHR = 2.11 (1.08-4.29)]. FRS did not modify the effect of ABC on MI (P = 0.14) and inclusion of FRS in the MSM did not diminish the effect of recent ABC use on the combined outcome. Recent ABC use was associated with MI after adjustment for known risk factors and for FRS. However, screening for T1MI risks may not identify all or even most persons at risk of ABC use-associated MIs.

Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

PubMed Central

Andersen, Vibeke; Svenningsen, Katrine; Knudsen, Lina Almind; Hansen, Axel Kornerup; Holmskov, Uffe; Stensballe, Allan; Vogel, Ulla

2015-01-01

AIM: To evaluate ATP-binding cassette (ABC) transporters in colonic pathophysiology as they had recently been related to colorectal cancer (CRC) development. METHODS: Literature search was conducted on PubMed using combinations of the following terms: ABC transporters, ATP binding cassette transporter proteins, inflammatory bowel disease, ulcerative, colitis, Crohns disease, colorectal cancer, colitis, intestinal inflammation, intestinal carcinogenesis, ABCB1/P-glycoprotein (P-gp/CD243/MDR1), ABCC2/multidrug resistance protein 2 (MRP2) and ABCG2/breast cancer resistance protein (BCRP), Abcb1/Mdr1a, abcc2/Mrp2, abcg2/Bcrp, knock-out mice, tight junction, membrane lipid function. RESULTS: Recently, human studies reported that changes in the levels of ABC transporters were early events in the adenoma-carcinoma sequence leading to CRC. A link between ABCB1, high fat diet and gut microbes in relation to colitis was suggested by the animal studies. The finding that colitis was preceded by altered gut bacterial composition suggests that deletion of Abcb1 leads to fundamental changes of host-microbiota interaction. Also, high fat diet increases the frequency and severity of colitis in specific pathogen-free Abcb1 KO mice. The Abcb1 KO mice might thus serve as a model in which diet/environmental factors and microbes may be controlled and investigated in relation to intestinal inflammation. Potential molecular mechanisms include defective transport of inflammatory mediators and/or phospholipid translocation from one side to the other of the cell membrane lipid bilayer by ABC transporters affecting inflammatory response and/or function of tight junctions, phagocytosis and vesicle trafficking. Also, diet and microbes give rise to molecules which are potential substrates for the ABC transporters and which may additionally affect ABC transporter function through nuclear receptors and transcriptional regulation. Another critical role of ABCB1 was suggested by the finding that ABCB1 expression identifies a subpopulation of pro-inflammatory Th17 cells which were resistant to treatment with glucocorticoids. The evidence for the involvement of ABCC2 and ABCG2 in colonic pathophysiology was weak. CONCLUSION: ABCB1, diet, and gut microbes mutually interact in colonic inflammation, a well-known risk factor for CRC. Further insight may be translated into preventive and treatment strategies. PMID:26557010

Doxorubicin loaded iron oxide nanoparticles overcome multidrug resistance in cancer in vitro

PubMed Central

Kievit, Forrest M.; Wang, Freddy Y.; Fang, Chen; Mok, Hyejung; Wang, Kui; Silber, John R.; Ellenbogen, Richard G.; Zhang, Miqin

2011-01-01

Multidrug resistance (MDR) is characterized by the overexpression of ATP-binding cassette (ABC) transporters that actively pump a broad class of hydrophobic chemotherapeutic drugs out of cancer cells. MDR is a major mechanism of treatment resistance in a variety of human tumors, and clinically applicable strategies to circumvent MDR remain to be characterized. Here we describe the fabrication and characterization of a drug-loaded iron oxide nanoparticle designed to circumvent MDR. Doxorubicin (DOX), an anthracycline antibiotic commonly used in cancer chemotherapy and substrate for ABC-mediated drug efflux, was covalently bound to polyethylenimine via a pH sensitive hydrazone linkage and conjugated to an iron oxide nanoparticle coated with amine terminated polyethylene glycol. Drug loading, physiochemical properties and pH lability of the DOX-hydrazone linkage were evaluated in vitro. Nanoparticle uptake, retention, and dose-dependent effects on viability were compared in wild-type and DOX-resistant ABC transporter over-expressing rat glioma C6 cells. We found that DOX release from nanoparticles was greatest at acidic pH, indicative of cleavage of the hydrazone linkage. DOX-conjugated nanoparticles were readily taken up by wild-type and drug-resistant cells. In contrast to free drug, DOX-conjugated nanoparticles persisted in drug-resistant cells, indicating that they were not subject to drug efflux. Greater retention of DOX-conjugated nanoparticles was accompanied by reduction of viability relative to cells treated with free drug. Our results suggest that DOX-conjugated nanoparticles could improve the efficacy of chemotherapy by circumventing MDR. PMID:21277920

Simultaneous Inhibition of PI3Kδ and PI3Kα Induces ABC-DLBCL Regression by Blocking BCR-Dependent and -Independent Activation of NF-κB and AKT.

PubMed

Paul, Juliane; Soujon, Maurice; Wengner, Antje M; Zitzmann-Kolbe, Sabine; Sturz, Andrea; Haike, Katja; Keng Magdalene, Koh Hui; Tan, Sze Huey; Lange, Martin; Tan, Soo Yong; Mumberg, Dominik; Lim, Soon Thye; Ziegelbauer, Karl; Liu, Ningshu

2017-01-09

Compared with follicular lymphoma, high PI3Kα expression was more prevalent in diffuse large B cell lymphoma (DLBCL), although both tumor types expressed substantial PI3Kδ. Simultaneous inhibition of PI3Kα and PI3Kδ dramatically enhanced the anti-tumor profile in ABC-DLBCL models compared with selective inhibition of PI3Kδ, PI3Kα, or BTK. The anti-tumor activity was associated with suppression of p-AKT and a mechanism of blocking nuclear factor-κB activation driven by CD79 mut , CARD11 mut , TNFAIP3 mut , or MYD88 mut . Inhibition of PI3Kα/δ resulted in tumor regression in an ibrutinib-resistant CD79B WT /MYD88 mut patient-derived ABC-DLBCL model. Furthermore, rebound activation of BTK and AKT was identified as a mechanism limiting CD79B mut -ABC-DLBCL to show a robust response to PI3K and BTK inhibitor monotherapies. A combination of ibrutinib with the PI3Kα/δ inhibitor copanlisib produced a sustained complete response in vivo in CD79B mut /MYD88 mut ABC-DLBCL models. Copyright © 2017 Elsevier Inc. All rights reserved.

Compact quadruple therapy with the lamivudine/zidovudine combination tablet plus abacavir and efavirenz, followed by the lamivudine/zidovudine/abacavir triple nucleoside tablet plus efavirenz in treatment-naïve HIV-infected adults.

PubMed

Ruane, Peter J; Parenti, David M; Margolis, David M; Shepp, David H; Babinchak, Timothy J; Van Kempen, Amy S; Kauf, Teresa L; Danehower, Susan A; Yau, Linda; Hessenthaler, Siegrid M; Goodwin, Diane; Hernandez, Jaime E

2003-01-01

To assess efficacy, safety, and adherence with compact quadruple therapy comprising one lamivudine 150-mg/zidovudine 300-mg tablet (COM) twice daily + one abacavir (ABC) 300-mg tablet twice daily + three efavirenz (EFV) 200-mg capsules at bedtime for 24 weeks, followed by one lamivudine 150-mg/zidovudine 300-mg/ABC 300-mg triple nucleoside tablet (TZV) twice daily + three EFV 200-mg capsules at bedtime for 24 weeks. A pilot 48-week, prospective, open-label trial in which 38 antiretroviral-naïve HIV-infected adults (baseline median HIV-1 RNA 5.1 log(10) copies/mL, CD4+ cell count 285/microL) received the above treatment and were monitored regularly with respect to plasma HIV-1 RNA levels, CD4+ cell counts, T-cell receptor excision circles (TRECs), adherence, and adverse events. At Week 48, intent-to-treat, switch-included analysis showed plasma HIV-1 RNA levels <400 copies/mL in 100% (29/29) of patients and <50 copies/mL in 93% (27/29); 59% of patients who achieved <50 copies/mL had <3 copies/mL (16/27). Similar virologic suppression was observed in patients with baseline HIV-1 RNA above or below 100000 copies/mL. HIV-1 RNA and CD4+ cell counts changed from baseline by a median of -3.4 log(10) copies/mL and +172 cells/microL, respectively. One virologic failure occurred at Week 16. Median TRECs/100000 peripheral blood lymphocytes increased 6-fold between baseline and Week 48. Median adherence rates were consistently 100% by self-report and 94% by pill count. Grade 2-4 treatment-related adverse events included dreams (16%), nausea (13%), decreased white cells (8%), dizziness (8%), sleep disorders (8%), and malaise and fatigue (8%). A suspected ABC hypersensitivity reaction occurred in 8% (3/38) of patients. COM/ABC/EFV or TZV/EFV produced potent, durable virologic suppression and immunologic benefits, was associated with high adherence rates, and was generally well tolerated.

Development and characterization of a long-acting nanoformulated abacavir prodrug

PubMed Central

Singh, Dhirender; McMillan, JoEllyn; Hilaire, James; Gautam, Nagsen; Palandri, Diana; Alnouti, Yazen; Gendelman, Howard E; Edagwa, Benson

2016-01-01

Aim: A myristoylated abacavir (ABC) prodrug was synthesized to extend drug half-life and bioavailability. Methods: Myristoylated ABC (MABC) was made by esterifying myristic acid to the drug's 5-hydroxy-cyclopentene group. Chemical composition, antiretroviral activity, cell uptake and retention and cellular trafficking of free MABC and poloxamer nanoformulations of MABC were assessed by proton nuclear magnetic resonance and tested in human monocyte-derived macrophages. Pharmacokinetics of ABC and nanoformulated MABC were evaluated after intramuscular injection into mice. Results: MABC antiretroviral activity in monocyte-derived macrophages was comparable to native drug. Encasement of MABC into poloxamer nanoparticles extended drug bioavailability for 2 weeks. Conclusion: MABC synthesis and encasement in polymeric nanoformulations improved intracellular drug accumulation and demonstrate translational potential as part of a long-acting antiretroviral regimen. PMID:27456759

Advanced patient age at diagnosis of diffuse large B-cell lymphoma is associated with molecular characteristics including ABC-subtype and high expression of MYC.

PubMed

Paul, Ulrike; Richter, Julia; Stuhlmann-Laiesz, Christiane; Kreuz, Markus; Nagel, Inga; Horn, Heike; Staiger, Annette M; Aukema, Sietse M; Hummel, Michael; Ott, German; Spang, Rainer; Rosenwald, Andreas; Feller, Alfred C; Cogliatti, Sergio; Stein, Harald; Hansmann, Martin-Leo; Moller, Peter; Szczepanowski, Monika; Burkhardt, Birgit; Pfreundschuh, Michael; Schmitz, Norbert; Loeffler, Markus; Trümper, Lorenz; Siebert, Reiner; Klapper, Wolfram

2018-05-01

The incidence of diffuse large B-cell lymphoma (DLBCL) increases with age being patient age at diagnosis an adverse prognostic factor. However, elderly patients are often underrepresented in common studies. To investigate the effect between age and biological characteristics in DLBCL, we analyzed data of 1534 patients encompassing all adult age groups, enriched for the age ≥75 years. Follicular lymphoma (FL) grade 3B with histopathological characteristics of DLBCLs were included. Gender, centroblastic cytology, FL grade 3B morphology, CD10 expression, and ABC/non-GCB-subtype were significantly associated with age after correction for multiple testing and after adjusting for cohorts. Analysis of a subgroup points towards an association of MYC expression with age. Our data indicate that biological features of DLBCL and FL grade 3B are associated with increasing age among adult patients. The prevalence of the ABC/non-GCB-subtype in elderly patients suggests that therapies targeting this molecular subtype should be specifically explored in this subgroup.

Characterization of the IPEC-J2 MDR1 (iP-gp) cell line as a tool for identification of P-gp substrates.

PubMed

Ozgür, Burak; Saaby, Lasse; Langthaler, Kristine; Brodin, Birger

2018-01-15

Recently, we transfected the porcine intestinal cell line IPEC-J2, with human P-glycoprotein (P-gp, ABCB1). The resulting cell line, iP-gp, has a high expression of functional human P-gp in the apical membrane, and a low expression of nonhuman ATP-binding cassette (ABC) transporters. The aim of the present work was to investigate the usability of iP-gp cell line for determining transepithelial transport kinetics of the prototypical P-gp substrates digoxin and rhodamine 123. The cell line generated tight monolayers after 16days of culture, reflected by high transepithelial electrical resistance values (TEER>15,000Ω·cm 2 ), immunocytochemistry and low fluxes of the paracellular flux marker [ 14 C]-mannitol. Monolayer integrity was not affected the common solvents dimethyl sulfoxide (DMSO), methanol and ethanol in concentrations up to 2% (v/v). Transepithelial fluxes of [ 3 H]-labeled digoxin and rhodamine 123 were measured at varying donor concentrations, and kinetic parameters were estimated. K m and V max of P-gp mediated basolateral-to-apical (B-A) flux of rhodamine 123 were estimated to 332±124μM and 111±16pmol·cm -2 ·min -1 (n=3, total N=6), respectively. V max and K m of digoxin B-A flux could not be estimated due to the low aqueous solubility of digoxin. The half maximal inhibitory concentrations (IC 50 ) of the selective P-gp inhibitor, zosuquidar (LY-335979), were estimated to 0.05±0.01μM (n=3, total N=6) and 0.04±0.01μM (n=3, total N=6) in transport experiments with digoxin and rhodamine 123 as substrates, respectively. Bidirectional fluxes of digoxin and rhodamine 123 were measured in transfected Madin Darby canine kidney cells (MDCK II MDR1) and compared with the fluxes obtained with the iP-gp cell monolayers. Efflux ratios were highest in the iP-gp cells, due to a tighter paracellular pathway. In conclusion, both digoxin and rhodamine 123 could be used to obtain IC 50 values of inhibition, K i values were only possible to obtain using rhodamine 123. The observed tightness, robustness towards solvents and the high efflux ratios confirmed that the iP-gp cell line may serve as a useful screening tool for investigations of substrate-P-gp interactions and modulation of P-gp function. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of Abcg2 During Mouse Embroyonic Stem Cell Diffferentiation

EPA Science Inventory

Role of Abcg2 During Mouse Embryonic Stem Cell Differentiation. Abcg2 is a multidrug resistance ATP-binding cassette (ABC) transporter whose activity may be considered a hallmark of stem cell plasticity. The role of Abcg2 during early embryogenesis, however, is unclear. Studies...

Deficiency of ATP-binding cassette transporters A1 and G1 in macrophages increases inflammation and accelerates atherosclerosis in mice.

PubMed

Westerterp, Marit; Murphy, Andrew J; Wang, Mi; Pagler, Tamara A; Vengrenyuk, Yuliya; Kappus, Mojdeh S; Gorman, Darren J; Nagareddy, Prabhakara R; Zhu, Xuewei; Abramowicz, Sandra; Parks, John S; Welch, Carrie; Fisher, Edward A; Wang, Nan; Yvan-Charvet, Laurent; Tall, Alan R

2013-05-24

Plasma high-density lipoprotein levels are inversely correlated with atherosclerosis. Although it is widely assumed that this is attributable to the ability of high-density lipoprotein to promote cholesterol efflux from macrophage foam cells, direct experimental support for this hypothesis is lacking. To assess the role of macrophage cholesterol efflux pathways in atherogenesis. We developed mice with efficient deletion of the ATP-binding cassette transporters A1 and G1 (ABCA1 and ABCG1) in macrophages (MAC-ABC(DKO) mice) but not in hematopoietic stem or progenitor populations. MAC-ABC(DKO) bone marrow (BM) was transplanted into Ldlr(-/-) recipients. On the chow diet, these mice had similar plasma cholesterol and blood monocyte levels but increased atherosclerosis compared with controls. On the Western-type diet, MAC-ABC(DKO) BM-transplanted Ldlr(-/-) mice had disproportionate atherosclerosis, considering they also had lower very low-density lipoprotein/low-density lipoprotein cholesterol levels than controls. ABCA1/G1-deficient macrophages in lesions showed increased inflammatory gene expression. Unexpectedly, Western-type diet-fed MAC-ABC(DKO) BM-transplanted Ldlr(-/-) mice displayed monocytosis and neutrophilia in the absence of hematopoietic stem and multipotential progenitor cells proliferation. Mechanistic studies revealed increased expressions of machrophage colony stimulating factor and granulocyte colony stimulating factor in splenic macrophage foam cells, driving BM monocyte and neutrophil production. These studies show that macrophage deficiency of ABCA1/G1 is proatherogenic likely by promoting plaque inflammation and uncover a novel positive feedback loop in which cholesterol-laden splenic macrophages signal BM progenitors to produce monocytes, with suppression by macrophage cholesterol efflux pathways.

Automating approximate Bayesian computation by local linear regression.

PubMed

Thornton, Kevin R

2009-07-07

In several biological contexts, parameter inference often relies on computationally-intensive techniques. "Approximate Bayesian Computation", or ABC, methods based on summary statistics have become increasingly popular. A particular flavor of ABC based on using a linear regression to approximate the posterior distribution of the parameters, conditional on the summary statistics, is computationally appealing, yet no standalone tool exists to automate the procedure. Here, I describe a program to implement the method. The software package ABCreg implements the local linear-regression approach to ABC. The advantages are: 1. The code is standalone, and fully-documented. 2. The program will automatically process multiple data sets, and create unique output files for each (which may be processed immediately in R), facilitating the testing of inference procedures on simulated data, or the analysis of multiple data sets. 3. The program implements two different transformation methods for the regression step. 4. Analysis options are controlled on the command line by the user, and the program is designed to output warnings for cases where the regression fails. 5. The program does not depend on any particular simulation machinery (coalescent, forward-time, etc.), and therefore is a general tool for processing the results from any simulation. 6. The code is open-source, and modular.Examples of applying the software to empirical data from Drosophila melanogaster, and testing the procedure on simulated data, are shown. In practice, the ABCreg simplifies implementing ABC based on local-linear regression.

Overexpression of a Phytophthora Cytoplasmic CRN Effector Confers Resistance to Disease, Salinity and Drought in Nicotiana benthamiana.

PubMed

Rajput, Nasir Ahmed; Zhang, Meixiang; Shen, Danyu; Liu, Tingli; Zhang, Qimeng; Ru, Yanyan; Sun, Peng; Dou, Daolong

2015-12-01

The Crinkler (CRN) effector family is produced by oomycete pathogens and may manipulate host physiological and biochemical events inside host cells. Here, PsCRN161 was identified from Phytophthora sojae based on its broad and strong cell death suppression activities. The effector protein contains two predicted nuclear localization signals and localized to nuclei of plant cells, indicating that it may target plant nuclei to modify host cell physiology and function. The chimeric gene GFP:PsCRN161 driven by the Cauliflower mosaic virus (CaMV) 35S promoter was introduced into Nicotiana benthamiana. The four independent PsCRN161-transgenic lines exhibited increased resistance to two oomycete pathogens (P. parasitica and P. capsici) and showed enhanced tolerance to salinity and drought stresses. Digital gene expression profiling analysis showed that defense-related genes, including ABC transporters, Cyt P450 and receptor-like kinases (RLKs), were significantly up-regulated in PsCRN161-transgenic plants compared with GFP (green fluorescent protein) lines, implying that PsCRN161 expression may protect plants from biotic and abiotic stresses by up-regulation of many defense-related genes. The results reveal previously unknown functions of the oomycete effectors, suggesting that the pathogen effectors could be directly used as functional genes for plant molecular breeding for enhancement of tolerance to biotic and abiotic stresses. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

[Effects of auditory integrative training on autistic children].

PubMed

Zhang, Gai-qiao; Gong, Qun; Zhang, Feng-ling; Chen, Sun-min; Hu, Li-qun; Liu, Feng; Cui, Rui-hua; He, Lin

2009-08-18

To explore the short-term treatment effect of the auditory integrative training on autistic children and provide them with clinical support for rehabilitative treatment. A total of 81 cases of autistic children were selected through the standard of DSM-4 and clinical case study was used. They were divided randomly into experimental group and control one, and respectively received auditory integrative training and no training based on the multiple therapies. The patients were investigated using clinical manifestation and Autism Behavior Checklist (ABC) and intelligence quotient (IQ) before and after six months of treatment. The effect was evaluated through the changes of clinical manifestations and scores of ABC and IQ. The changes of scores of IQ were determined with Gesell and WPPSI or WISC-R. Compared with 40 patients of the control group after the six months of the auditory integrative training, 41 of the experimental group had greatly improved in many aspects, such as the disorders of their language, social interactions and typical behavior symptoms while they had not changed in their abnormal behaviors. The scores of IQ or DQ had increased and scores of ABC had dropped. The differences between the two groups were greatly significant in statistics (P < 0.01). The decreasing level of both ABC scores and the increasing level of the IQ scores were negatively correlated with age, and the decreasing level of ABC scores was in line regression(positive correlation) with base IQ. The treatment of auditory integrative training (AIT) could greatly improve on language disorders, the difficulties of social interactions, typical behavior symptoms and developmental levels,therefore it is positive to the autistic children in its short-term treatment effect.

Total nucleated cell and leukocyte differential counts in canine pleural and peritoneal fluid and equine synovial fluid samples: comparison of automated and manual methods.

PubMed

Brudvig, Jean M; Swenson, Cheryl L

2015-12-01

Rapid and precise measurement of total and differential nucleated cell counts is a crucial diagnostic component of cavitary and synovial fluid analyses. The objectives of this study included (1) evaluation of reliability and precision of canine and equine fluid total nucleated cell count (TNCC) determined by the benchtop Abaxis VetScan HM5, in comparison with the automated reference instruments ADVIA 120 and the scil Vet abc, respectively, and (2) comparison of automated with manual canine differential nucleated cell counts. The TNCC and differential counts in canine pleural and peritoneal, and equine synovial fluids were determined on the Abaxis VetScan HM5 and compared with the ADVIA 120 and Vet abc analyzer, respectively. Statistical analyses included correlation, least squares fit linear regression, Passing-Bablok regression, and Bland-Altman difference plots. In addition, precision of the total cell count generated by the VetScan HM5 was determined. Agreement was excellent without significant constant or proportional bias for canine cavitary fluid TNCC. Automated and manual differential counts had R(2)  < .5 for individual cell types (least squares fit linear regression). Equine synovial fluid TNCC agreed but with some bias due to the VetScan HM5 overestimating TNCC compared to the Vet abc. Intra-assay precision of the VetScan HM5 in 3 fluid samples was 2-31%. The Abaxis VetScan HM5 provided rapid, reliable TNCC for canine and equine fluid samples. The differential nucleated cell count should be verified microscopically as counts from the VetScan HM5 and also from the ADVIA 120 were often incorrect in canine fluid samples. © 2015 American Society for Veterinary Clinical Pathology.

Solid Variant of an Aneurysmal Bone Cyst of the Thoracic Spine.

PubMed

Mehta, Varshil; Padalkar, Pravin; Kale, Maya; Kathare, Ambadas

2017-05-01

The solid variant of an aneurysmal bone cyst (ABC) has been observed very rarely, especially those involving the spine. In this case report, we present a very unusual tumour of the thoracic spine which was managed by 360˚ decompression via posterior-only approach and stabilization. A 16-year-old boy presented to us with a sudden onset of weakness in both lower limbs leading to paraplegia. He also had a history of back and chest pain over the past one year. A collapse of the T5 vertebrae on plain radiograph was observed. The patient was immediately shifted to the operation theatre with an initial plan of a total en bloc spondylectomy of the T5. However, intraoperatively, histology favored a solid-ABC variant rather than a spindle cell tumour or giant cell tumour. Thus, the initial plan was revised to a 360˚ decompression without resecting the body en bloc via a posterolateral approach. After surgery, complete resolution of his sensory and motor dysfunction was achieved. His chest and back pain also resolved. The diseased vertebral body gradually healed and new bone formation was seen at 18 months postoperatively. This case report concludes that a solid variant of an ABC should be considered as a differential diagnosis for tumours involving the spine. An intraoperative frozen section procedure should be undertaken, especially during emergency situations. Early diagnosis and appropriate surgical management play an important role in the successful management of a solid variant of ABC.

Describing the role of Drosophila melanogaster ABC transporters in insecticide biology using CRISPR-Cas9 knockouts.

PubMed

Denecke, Shane; Fusetto, Roberto; Batterham, Philip

2017-12-01

ABC transporters have a well-established role in drug resistance, effluxing xenobiotics from cells and tissues within the organism. More recently, research has been dedicated to understanding the role insect ABC transporters play in insecticide toxicity, but progress in understanding the contribution of specific transporters has been hampered by the lack of functional genetic tools. Here, we report knockouts of three Drosophila melanogaster ABC transporter genes, Mdr49, Mdr50, and Mdr65, that are homologous to the well-studied mammalian ABCB1 (P-glycoprotein). Each knockout mutant was created in the same wild type background and tested against a panel of insecticides representing different chemical classes. Mdr65 knockouts were more susceptible to all neuroactive insecticides tested, but Mdr49 and Mdr50 knockouts showed increased susceptibility or resistance depending on the insecticide used. Mdr65 was chosen for further analysis. Calculation of LC 50 values for the Mdr65 knockout allowed the substrate specificity of this transporter to be examined. No obvious distinguishing structural features were shared among MDR65 substrates. A role for Mdr65 in insecticide transport was confirmed by testing the capacity of the knockout to synergize with the ABC inhibitor verapamil and by measuring the levels of insecticide retained in the body of knockout flies. These data unambiguously establish the influence of ABC transporters on the capacity of wild type D. melanogaster to tolerate insecticide exposure and suggest that both tissue and substrate specificity underpin this capacity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Suppression of HIV-1 Infectivity by Human Glioma Cells

PubMed Central

Hoque, Sheikh Ariful; Tanaka, Atsushi; Islam, Salequl; Ahsan, Gias Uddin; Jinno-Oue, Atsushi

2016-01-01

Abstract HIV-1 infection to the central nervous system (CNS) is very common in AIDS patients. The predominant cell types infected in the brain are monocytes and macrophages, which are surrounded by several HIV-1–resistant cell types, such as astrocytes, oligodendrocytes, neurons, and microvascular cells. The effect of these HIV-1–resistant cells on HIV-1 infection is largely unknown. In this study, we examined the stability of HIV-1 cultured with several human glioblastoma cell lines, for example, NP-2, U87MG, T98G, and A172, to determine whether these HIV-1–resistant brain cells could enhance or suppress HIV-1 infection and thus modulate HIV-1 infection in the CNS. The HIV-1 titer was determined using the MAGIC-5A indicator cell line as well as naturally occurring CD4+ T cells. We found that the stability of HIV-1 incubated with NP-2 or U87MG cells at 37°C was significantly shorter (half-life, 2.5–4 h) compared to that of HIV-1 incubated with T98G or A172 cells or in culture medium without cells (half-life, 8–18 h). The spent culture media (SCM) of NP-2 and U87MG cells had the ability to suppress both R5- and X4-HIV-1 infection by inhibiting HIV-1 attachment to target cells. This inhibitory effect was eliminated by the treatment of the SCM with chondroitinase ABC but not heparinase, suggesting that the inhibitory factor(s) secreted by NP-2 and U87MG cells was chiefly mediated by chondroitin sulfate (CS) or CS-like moiety. Thus, this study reveals that some but not all glioma cells secrete inhibitory molecules to HIV-1 infection that may contribute in lowering HIV-1 infection in the CNS in vivo. PMID:26650729

Glutathione S-transferase expression and isoenzyme composition during cell differentiation of Caco-2 cells.

PubMed

Scharmach, E; Hessel, S; Niemann, B; Lampen, A

2009-11-30

The human colon adenocarcinoma cell line Caco-2 is frequently used to study human intestinal metabolism and transport of xenobiotica. Previous studies have shown that both Caco-2 cells and human colon cells constitutively express the multigene family of detoxifying enzymes glutathione S-transferases (GSTs), particularly GST alpha and GST pi. GSTs may play a fundamental role in the molecular interplay between phase I, II enzymes and ABC-transporters. The gut fermentation product, butyrate, can modulate the potential for detoxification. The aim of this study was to investigate the basal expression of further cytosolic GSTs in Caco-2 cells during cell differentiation. In addition, a comparison was made with expression levels in MCF-7 and HepG2, two other cell types with barrier functions. Finally, the butyrate-mediated modulation of gene and protein expression was determined by real time PCR and western blot analysis. In Caco-2, gene and protein expression levels of GST alpha increased during cell differentiation. High levels of GSTO1 and GSTP1 were constantly expressed. No expression of GSTM5 and GSTT1 was detected. HepG2 expressed GSTO1 and MCF-7 GSTZ1 most intensively. No expression of GSTA5, GSTM5, or GSTP1 was detected in either cell. Incubation of Caco-2 cells with butyrate (5 mM) significantly induced GSTA1 and GSTM2 in proliferating Caco-2 cells. In differentiated cells, butyrate tended to increase GSTO1 and GSTP1. The results of this study show that a differentiation-dependent expression of GSTs in Caco-2 cells may reflect the in vivo situation and indicate the potential of butyrate to modify intestinal metabolism. GSTA1-A4 have been identified as good markers for cell differentiation. The Caco-2 cell line is a useful model for assessing the potential of food-related substances to modulate the GST expression pattern.

Alkyl-Lysophospholipid Resistance in Multidrug-Resistant Leishmania tropica and Chemosensitization by a Novel P-Glycoprotein-Like Transporter Modulator

PubMed Central

Pérez-Victoria, José M.; Pérez-Victoria, F. Javier; Parodi-Talice, Adriana; Jiménez, Ignacio A.; Ravelo, Angel G.; Castanys, Santiago; Gamarro, Francisco

2001-01-01

Drug resistance has emerged as a major impediment in the treatment of leishmaniasis. Alkyl-lysophospholipids (ALP), originally developed as anticancer drugs, are considered to be the most promising antileishmanial agents. In order to anticipate probable clinical failure in the near future, we have investigated possible mechanisms of resistance to these drugs in Leishmania spp. The results presented here support the involvement of a member of the ATP-binding cassette (ABC) superfamily, the Leishmania P-glycoprotein-like transporter, in the resistance to ALP. (i) First, a multidrug resistance (MDR) Leishmania tropica line overexpressing a P-glycoprotein-like transporter displays significant cross-resistance to the ALP miltefosine and edelfosine, with resistant indices of 9.2- and 7.1-fold, respectively. (ii) Reduced expression of P-glycoprotein in the MDR line correlates with a significant decrease in ALP resistance. (iii) The ALP were able to modulate the P-glycoprotein-mediated resistance to daunomycin in the MDR line. (iv) We have found a new inhibitor of this transporter, the sesquiterpene C-3, that completely sensitizes MDR parasites to ALP. (v) Finally, the MDR line exhibits a lower accumulation than the wild-type line of bodipy-C5-PC, a fluorescent analogue of phosphatidylcholine that has a structure resembling that of edelfosine. Also, C-3 significantly increases the accumulation of the fluorescent analogue to levels similar to those of wild-type parasites. The involvement of the Leishmania P-glycoprotein-like transporter in resistance to drugs used in the treatment of leishmaniasis also supports the importance of developing new specific inhibitors of this ABC transporter. PMID:11502516

Secondary Metabolites from Plants Inhibiting ABC Transporters and Reversing Resistance of Cancer Cells and Microbes to Cytotoxic and Antimicrobial Agents

PubMed Central

Wink, Michael; Ashour, Mohamed L.; El-Readi, Mahmoud Zaki

2012-01-01

Fungal, bacterial, and cancer cells can develop resistance against antifungal, antibacterial, or anticancer agents. Mechanisms of resistance are complex and often multifactorial. Mechanisms include: (1) Activation of ATP-binding cassette (ABC) transporters, such as P-gp, which pump out lipophilic compounds that have entered a cell, (2) Activation of cytochrome p450 oxidases which can oxidize lipophilic agents to make them more hydrophilic and accessible for conjugation reaction with glucuronic acid, sulfate, or amino acids, and (3) Activation of glutathione transferase, which can conjugate xenobiotics. This review summarizes the evidence that secondary metabolites (SM) of plants, such as alkaloids, phenolics, and terpenoids can interfere with ABC transporters in cancer cells, parasites, bacteria, and fungi. Among the active natural products several lipophilic terpenoids [monoterpenes, diterpenes, triterpenes (including saponins), steroids (including cardiac glycosides), and tetraterpenes] but also some alkaloids (isoquinoline, protoberberine, quinoline, indole, monoterpene indole, and steroidal alkaloids) function probably as competitive inhibitors of P-gp, multiple resistance-associated protein 1, and Breast cancer resistance protein in cancer cells, or efflux pumps in bacteria (NorA) and fungi. More polar phenolics (phenolic acids, flavonoids, catechins, chalcones, xanthones, stilbenes, anthocyanins, tannins, anthraquinones, and naphthoquinones) directly inhibit proteins forming several hydrogen and ionic bonds and thus disturbing the 3D structure of the transporters. The natural products may be interesting in medicine or agriculture as they can enhance the activity of active chemotherapeutics or pesticides or even reverse multidrug resistance, at least partially, of adapted and resistant cells. If these SM are applied in combination with a cytotoxic or antimicrobial agent, they may reverse resistance in a synergistic fashion. PMID:22536197

HLA-B*57:01 allele prevalence in HIV-infected North American subjects and the impact of allele testing on the incidence of abacavir-associated hypersensitivity reaction in HLA-B*57:01-negative subjects.

PubMed

Small, Catherine Butkus; Margolis, David A; Shaefer, Mark S; Ross, Lisa L

2017-04-11

The presence of the HLA-B*57:01 allele in HIV-infected subjects is associated with a higher risk of abacavir-associated hypersensitivity reaction (ABC HSR). HLA-B*57:01 allele prevalence varies in different populations, but HLA-B*57:01 testing with immunological confirmation has had a negative predictive value for ABC HSR between 97 and 100%. In the ASSURE study (EPZ113734), the HLA-B*57:01 prevalence in virologically suppressed, antiretroviral treatment-experienced, HIV-infected subjects from the United States, including Puerto Rico, was assessed. Three hundred eighty-five subjects were screened; 13 were HLA-B*57:01 positive and 372 were negative. Only HLA-B*57:01-negative, abacavir-naive subjects were eligible to enroll into the ASSURE trial. Eleven of the 13 subjects who possessed the HLA-B*57:01 allele were white, the other 2 were African-American. There was no geographic clustering of HLA-B*57:01-positive subjects, and the incidence correlated roughly with those states with the greatest numbers of subjects screened. Similarly, there was no statistically significant correlation between subjects who possessed or lacked the allele and age, gender, ethnicity or CD4+ T-cell numbers. The incidence of ABC HSR following abacavir initiation was also evaluated. Only 1 of 199 HLA-B*57:01-negative subjects (an African-American male) randomized to receive abacavir-containing treatment developed symptoms consistent with suspected ABC HSR; ABC HSR was not immunologically confirmed. These findings confirm the utility of HLA-B*57:01 allele testing to reduce the frequency of ABC HSR. The prevalence of HLA-B*57:01 positivity was higher in white than in African-American subjects. In HLA-B*57:01-negative subjects, suspected ABC HSR is very rare, but should lead to discontinuation of abacavir when ABC HSR cannot be definitively excluded from the differential diagnosis. The ASSURE (EPZ113734) study was registered on ClinicalTrials.gov registration on April 8th 2010 and the registration number is NCT01102972.

Regulation of ATP-binding Cassette Transporters and Cholesterol Efflux by Glucose in Primary Human Monocytes and Murine Bone Marrow-derived Macrophages

PubMed Central

Spartano, N. L.; Lamon-Fava, S.; Matthan, N. R.; Ronxhi, J.; Greenberg, A. S.; Obin, M. S.; Lichtenstein, A. H.

2014-01-01

Purpose Individuals with type 2 diabetes mellitus are at increased risk of developing atherosclerosis. This may be partially attributable to suppression of macrophage ATP-binding cassette (ABC) transporter mediated cholesterol efflux by sustained elevated blood glucose concentrations. 2 models were used to assess this potential relationship: human monocytes/leukocytes and murine bone marrow-derived macrophages (BMDM). Methods 10 subjects (4 F/6 M, 50–85 years, BMI 25–35 kg/m2) underwent an oral glucose challenge. Baseline and 1- and 2-h post-challenge ABC-transporter mRNA expression was determined in monocytes, leukocytes and peripheral blood mononuclear cells (PBMC). In a separate study, murine-BMDM were exposed to 5 mmol/L D-glucose (control) or additional 20 mmol/L D-or L-glucose and 25 ug/mL oxidized low density lipoprotein (oxLDL). High density lipoprotein (HDL)-mediated cholesterol efflux and ABC-transporter (ABCA1 and ABCG1) expression were determined. Results Baseline ABCA1and ABCG1 expression was lower (> 50 %) in human monocytes and PBMC than leukocytes (p < 0.05). 1 h post-challenge leukocyte ABCA1 and ABCG1 expression increased by 37 % and 30 %, respectively (p < 0.05), and began to return to baseline thereafter. There was no significant change in monocyte ABC-transporter expression. In murine BMDM, higher glucose concentrations suppressed HDL-mediated cholesterol efflux (10 %; p < 0.01) without significantly affecting ABCA1 and ABCG1 expression. Data demonstrate that leukocytes are not a reliable indicator of monocyte ABC-transporter expression. Conclusions Human monocyte ABC-transporter gene expression was unresponsive to a glucose challenge. Correspondingly, in BMDM, hyperglycemia attenuated macrophage cholesterol efflux in the absence of altered ABC-transporter expression, suggesting that hyperglycemia, per se, suppresses cholesterol transporter activity. This glucose-related impairment in cholesterol efflux may potentially contribute to diabetes-associated atherosclerosis. PMID:24838154

Examination of the Combined Effects of Chondroitinase ABC, Growth Factors and Locomotor Training following Compressive Spinal Cord Injury on Neuroanatomical Plasticity and Kinematics

PubMed Central

Alluin, Olivier; Fehlings, Michael G.; Rossignol, Serge; Karimi-Abdolrezaee, Soheila

2014-01-01

While several cellular and pharmacological treatments have been evaluated following spinal cord injury (SCI) in animal models, it is increasingly recognized that approaches to address the glial scar, including the use of chondroitinase ABC (ChABC), can facilitate neuroanatomical plasticity. Moreover, increasing evidence suggests that combinatorial strategies are key to unlocking the plasticity that is enabled by ChABC. Given this, we evaluated the anatomical and functional consequences of ChABC in a combinatorial approach that also included growth factor (EGF, FGF2 and PDGF-AA) treatments and daily treadmill training on the recovery of hindlimb locomotion in rats with mid thoracic clip compression SCI. Using quantitative neuroanatomical and kinematic assessments, we demonstrate that the combined therapy significantly enhanced the neuroanatomical plasticity of major descending spinal tracts such as corticospinal and serotonergic-spinal pathways. Additionally, the pharmacological treatment attenuated chronic astrogliosis and inflammation at and adjacent to the lesion with the modest synergistic effects of treadmill training. We also observed a trend for earlier recovery of locomotion accompanied by an improvement of the overall angular excursions in rats treated with ChABC and growth factors in the first 4 weeks after SCI. At the end of the 7-week recovery period, rats from all groups exhibited an impressive spontaneous recovery of the kinematic parameters during locomotion on treadmill. However, although the combinatorial treatment led to clear chronic neuroanatomical plasticity, these structural changes did not translate to an additional long-term improvement of locomotor parameters studied including hindlimb-forelimb coupling. These findings demonstrate the beneficial effects of combined ChABC, growth factors and locomotor training on the plasticity of the injured spinal cord and the potential to induce earlier neurobehavioral recovery. However, additional approaches such as stem cell therapies or a more adapted treadmill training protocol may be required to optimize this repair strategy in order to induce sustained functional locomotor improvement. PMID:25350665

Comparison of cardiovascular disease risk markers in HIV-infected patients receiving abacavir and tenofovir: the nucleoside inflammation, coagulation and endothelial function (NICE) study

PubMed Central

Wohl, David A; Arnoczy, Gretchen; Fichtenbaum, Carl J; Campbell, Thomas; Taiwo, Babafemi; Hicks, Charles; McComsey, Grace A; Koletar, Susan; Sax, Paul; Tebas, Pablo; Ha, Belinda; Massengale, Kelly; Walsh, Kendall; Stein, James H

2015-01-01

Background The association between abacavir (ABC) and cardiovascular disease (CVD) risk in HIV-infected individuals is unclear. Putative mechanisms for an effect of ABC on CVD risk including endothelial dysfunction have been proposed; however, a biological mechanism has not been established. Methods This was a cross-sectional study of HIV-infected subjects with HIV RNA levels <400 copies/ml, who were randomly assigned to ABC or tenofovir (TDF) as initial therapy during a prior clinical trial. A small cohort of subjects on zidovudine (AZT; not randomly assigned) were studied to explore long-term exposure to this agent. All underwent brachial artery ultrasound for flow-mediated dilation (FMD), and D-dimer, high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6) and fasting lipids were measured. Between-arm differences were evaluated by multivariable linear or logistic regression modelling. Results There were 148 subjects (46 on ABC, 72 on TDF and 30 on AZT). Demographic characteristics were balanced across the groups except, as expected, AZT-treated participants were older, had higher CD4+ T-cell counts, and longer antiretroviral therapy duration. After adjusting for age, brachial artery diameter, and treatment duration, FMD was similar in those on ABC (3.9%) and TDF (5.4%; P=0.181). FMD was higher in those on AZT (6.1%; P<0.005). Levels of IL-6, hsCRP and detectable D-dimer were similar between groups. Conclusions Among individuals assigned to ABC or TDF in randomized clinical trials there were no significant differences in FMD or markers of inflammation and coagulation. Whether ABC contributes to risk of CVD remains unclear, but our results suggest that endothelial dysfunction, heightened inflammation, and altered coagulation are unlikely to be mechanisms by which the drug could increase CVD risk above that seen with TDF. PMID:23985706

Enterococcus faecalis Ebp pili are important for cell-cell aggregation and intraspecies gene transfer

PubMed Central

Leanti La Rosa, Sabina; Camila Montealegre, Maria; Singh, Kavindra V.

2016-01-01

Enterococcus faecalis is an opportunistic pathogen that ranks among the leading causes of biofilm-associated infections. We previously demonstrated that the endocarditis- and biofilm-associated pili (Ebp) of E. faecalis play a major role in biofilm formation, adherence to abiotic surfaces and experimental infections. In this study, derivatives of E. faecalis strain OG1 were engineered to further characterize functions of Ebp pili. Loss of pili resulted in a 36-fold decrease in the number of closely associated cells when OG1RFΔebpABC was mixed with OG1SSpΔebpABC, compared with mixing the Ebp+ parental strains. In addition, using the Ebp+ parental strains as donor and recipient, we found a statistically significant increase (280–360 %, P < 0.05) in the frequency of plasmid transfer versus using Ebp−  mutants in the conjugation experiments. These results demonstrate a previously unrecognized role of Ebp pili, namely, as important contributors to microscale cell aggregation and horizontal spread of genetic material. PMID:26967674

Mechanism for the antibacterial action of epigallocatechin gallate (EGCg) on Bacillus subtilis.

PubMed

Nakayama, Motokazu; Shimatani, Kanami; Ozawa, Tadahiro; Shigemune, Naofumi; Tomiyama, Daisuke; Yui, Koji; Katsuki, Mao; Ikeda, Keisuke; Nonaka, Ai; Miyamoto, Takahisa

2015-01-01

Catechins are a class of polyphenols and have high anti-bacterial activity against various microorganisms. Here, we report the mechanism for antibacterial activity of epigallocatechin gallate (EGCg) against Gram-positive bacteria Bacillus subtilis, which is highly sensitive to EGCg. Transmission electron microscope analysis revealed that deposits containing EGCg were found throughout the cell envelope from the outermost surface to the outer surface of cytoplasmic membrane. Aggregating forms of proteins and EGCg were identified as spots that disappeared or showed markedly decreased intensity after the treatment with EGCg compared to the control by two-dimensional electrophoresis. Among the identified proteins included 4 cell surface proteins, such as oligopeptide ABC transporter binding lipoprotein, glucose phosphotransferase system transporter protein, phosphate ABC transporter substrate-binding protein, and penicillin-binding protein 5. Observations of glucose uptake of cells and cell shape B. subtilis after the treatment with EGCg suggested that EGCg inhibits the major functions of these proteins, leading to growth inhibition of B. subtilis.

The short version of the Activities-specific Balance Confidence (ABC) scale: its validity, reliability, and relationship to balance impairment and falls in older adults.

PubMed

Schepens, Stacey; Goldberg, Allon; Wallace, Melissa

2010-01-01

A shortened version of the ABC 16-item scale (ABC-16), the ABC-6, has been proposed as an alternative balance confidence measure. We investigated whether the ABC-6 is a valid and reliable measure of balance confidence and examined its relationship to balance impairment and falls in older adults. Thirty-five community-dwelling older adults completed the ABC-16, including the 6 questions of the ABC-6. They also completed the following clinical balance tests: unipedal stance time (UST), functional reach (FR), Timed Up and Go (TUG), and maximum step length (MSL). Participants reported 12-month falls history. Balance confidence on the ABC-6 was significantly lower than on the ABC-16, however scores were highly correlated. Fallers reported lower balance confidence than non-fallers as measured by the ABC-6 scale, but confidence did not differ between the groups with the ABC-16. The ABC-6 significantly correlated with all balance tests assessed and number of falls. The ABC-16 significantly correlated with all balance tests assessed, but not with number of falls. Test-retest reliability for the ABC-16 and ABC-6 was good to excellent. The ABC-6 is a valid and reliable measure of balance confidence in community-dwelling older adults, and shows stronger relationships to falls than does the ABC-16. The ABC-6 may be a more useful balance confidence assessment tool than the ABC-16. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

Structural basis for allosteric cross-talk between the asymmetric nucleotide binding sites of a heterodimeric ABC exporter.

PubMed

Hohl, Michael; Hürlimann, Lea M; Böhm, Simon; Schöppe, Jendrik; Grütter, Markus G; Bordignon, Enrica; Seeger, Markus A

2014-07-29

ATP binding cassette (ABC) transporters mediate vital transport processes in every living cell. ATP hydrolysis, which fuels transport, displays positive cooperativity in numerous ABC transporters. In particular, heterodimeric ABC exporters exhibit pronounced allosteric coupling between a catalytically impaired degenerate site, where nucleotides bind tightly, and a consensus site, at which ATP is hydrolyzed in every transport cycle. Whereas the functional phenomenon of cooperativity is well described, its structural basis remains poorly understood. Here, we present the apo structure of the heterodimeric ABC exporter TM287/288 and compare it to the previously solved structure with adenosine 5'-(β,γ-imido)triphosphate (AMP-PNP) bound at the degenerate site. In contrast to other ABC exporter structures, the nucleotide binding domains (NBDs) of TM287/288 remain in molecular contact even in the absence of nucleotides, and the arrangement of the transmembrane domains (TMDs) is not influenced by AMP-PNP binding, a notion confirmed by double electron-electron resonance (DEER) measurements. Nucleotide binding at the degenerate site results in structural rearrangements, which are transmitted to the consensus site via two D-loops located at the NBD interface. These loops owe their name from a highly conserved aspartate and are directly connected to the catalytically important Walker B motif. The D-loop at the degenerate site ties the NBDs together even in the absence of nucleotides and substitution of its aspartate by alanine is well-tolerated. By contrast, the D-loop of the consensus site is flexible and the aspartate to alanine mutation and conformational restriction by cross-linking strongly reduces ATP hydrolysis and substrate transport.

Discovering Problem Solving Strategies: What Humans Do and Machines Don’t (Yet)

DTIC Science & Technology

1989-07-21

will.... 124. So, I will go back from B to A. During lines 119-124, the subject waffles abc ,! using rule 6 of the minor move strategy. She seems to...1987). Acquiring effective search control rules: Explanation-based learning in the Prodigy sytem . In P. Langley (Ed.), Proceedings of the Fourth

ABCG2/BCRP decreases the transfer of a food-born chemical carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in perfused term human placenta.

PubMed

Myllynen, Päivi; Kummu, Maria; Kangas, Tiina; Ilves, Mika; Immonen, Elina; Rysä, Jaana; Pirilä, Rauna; Lastumäki, Anni; Vähäkangas, Kirsi H

2008-10-15

We have studied the role of ATP binding cassette (ABC) transporters in fetal exposure to carcinogens using 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) a known substrate for ABC transporters as a model compound. In perfusion of human term placenta, transfer of (14)C-PhIP (2 microM) through the placenta resulted in fetal-to-maternal concentration ratio (FM ratio) of 0.72+/-0.09 at 6 h. The specific ABCG2 inhibitor KO143 increased the transfer of (14)C-PhIP from maternal to fetal circulation (FM ratio 0.90+/-0.08 at 6 h, p<0.05) while the ABCC1/ABCC2 inhibitor probenecid had no effect (FM ratio at 6 h 0.75+/-0.10, p=0.84). There was a negative correlation between the expression of ABCG2 protein in perfused tissue and the FM ratio of (14)C-PhIP (R=-0.81, p<0.01) at the end of the perfusion. The expression of ABCC2 protein did not correlate with FM ratio of PhIP (R: -0.11, p=0.76). In addition, PhIP induced the expression of ABC transporters in BeWo cells at mRNA level. In conclusion, our data indicates that ABCG2 decreases placental transfer of (14)C-PhIP in perfused human placenta. Also, PhIP may modify ABC transporter expression in choriocarcinoma cells.

A phylogenomic analysis of the Actinomycetales mce operons.

PubMed

Casali, Nicola; Riley, Lee W

2007-02-26

The genome of Mycobacterium tuberculosis harbors four copies of a cluster of genes termed mce operons. Despite extensive research that has demonstrated the importance of these operons on infection outcome, their physiological function remains obscure. Expanding databases of complete microbial genome sequences facilitate a comparative genomic approach that can provide valuable insight into the role of uncharacterized proteins. The M. tuberculosis mce loci each include two yrbE and six mce genes, which have homology to ABC transporter permeases and substrate-binding proteins, respectively. Operons with an identical structure were identified in all Mycobacterium species examined, as well as in five other Actinomycetales genera. Some of the Actinomycetales mce operons include an mkl gene, which encodes an ATPase resembling those of ABC uptake transporters. The phylogenetic profile of Mkl orthologs exactly matched that of the Mce and YrbE proteins. Through topology and motif analyses of YrbE homologs, we identified a region within the penultimate cytoplasmic loop that may serve as the site of interaction with the putative cognate Mkl ATPase. Homologs of the exported proteins encoded adjacent to the M. tuberculosis mce operons were detected in a conserved chromosomal location downstream of the majority of Actinomycetales operons. Operons containing linked mkl, yrbE and mce genes, resembling the classic organization of an ABC importer, were found to be common in Gram-negative bacteria and appear to be associated with changes in properties of the cell surface. Evidence presented suggests that the mce operons of Actinomycetales species and related operons in Gram-negative bacteria encode a subfamily of ABC uptake transporters with a possible role in remodeling the cell envelope.

ABCG2/BCRP decreases the transfer of a food-born chemical carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in perfused term human placenta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myllynen, Paeivi; Kummu, Maria; Kangas, Tiina

2008-10-15

We have studied the role of ATP binding cassette (ABC) transporters in fetal exposure to carcinogens using 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) a known substrate for ABC transporters as a model compound. In perfusion of human term placenta, transfer of {sup 14}C-PhIP (2 {mu}M) through the placenta resulted in fetal-to-maternal concentration ratio (FM ratio) of 0.72 {+-} 0.09 at 6 h. The specific ABCG2 inhibitor KO143 increased the transfer of {sup 14}C-PhIP from maternal to fetal circulation (FM ratio 0.90 {+-} 0.08 at 6 h, p < 0.05) while the ABCC1/ABCC2 inhibitor probenecid had no effect (FM ratio at 6 h 0.75 {+-}more » 0.10, p = 0.84). There was a negative correlation between the expression of ABCG2 protein in perfused tissue and the FM ratio of {sup 14}C-PhIP (R = - 0.81, p < 0.01) at the end of the perfusion. The expression of ABCC2 protein did not correlate with FM ratio of PhIP (R: - 0.11, p = 0.76). In addition, PhIP induced the expression of ABC transporters in BeWo cells at mRNA level. In conclusion, our data indicates that ABCG2 decreases placental transfer of {sup 14}C-PhIP in perfused human placenta. Also, PhIP may modify ABC transporter expression in choriocarinoma cells.« less

The effect of epigallocatechin-3-gallate (EGCG) on human alveolar bone cells both in vitro and in vivo.

PubMed

Mah, Yon-Joo; Song, Je Seon; Kim, Seong-Oh; Lee, Jae-Ho; Jeon, Mijeong; Jung, Ui-Won; Moon, Seok Jun; Kim, Jeong-Hee; Choi, Hyung-Jun

2014-05-01

The effects of epigallocatechin-3-gallate (EGCG), a major catechin in green tea, on human and mouse osteoblasts remain controversial. This study investigated the direct effects of EGCG on human alveolar bone-derived cells (hABCs) both in vitro and in vivo. hABCs which were collected from eight children (aged 7-9 years, seven males and one female) were treated with EGCG at various concentrations (1, 5, 10, 25, and 50μM), and a proliferation assay, flow cytometric analysis for apoptosis evaluation, migration assay, and in vitro osteogenic differentiation were performed. hABCs that were pretreated with 10μM EGCG and mixed with calcium phosphate carrier combined with EGCG (0.1, 0.5, or 1.5mg) in vivo were transplanted into immunodeficient mouse. Histological staining, quantitative gene expressions, and alkaline phosphatase activity were evaluated in the retrieved transplants. The proliferation and migration were decreased when EGCG was present at over 25μM. The osteogenic differentiation increased slightly when EGCG was present at up to 10μM, and clearly decreased for higher concentrations of EGCG. In vivo, the potential for hard-tissue formation was slightly higher for the group with 0.1mg of EGCG than for the control group, and decreased sharply for higher concentrations of EGCG. The present observations suggest that EGCG at a low concentration can slightly enhance the osteogenic effect in vivo, whereas at a higher concentration it can prevent the osteogenic differentiation of hABCs both in vitro and in vivo. Copyright © 2014 Elsevier Ltd. All rights reserved.

The enhancing effect of genistein on apoptosis induced by trichostatin A in lung cancer cells with wild type p53 genes is associated with upregulation of histone acetyltransferase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Tzu-Chin; Lin, Yi-Chin; Chen, Hsiao-Ling

Genistein has been shown to enhance the antitumor activity of trichostatin A (TSA) in human lung carcinoma A549 cells. However, whether the combined treatment exerts the same effect in other lung cancer cells is unclear. In the present study we first compared the enhancing effect of genistein on the antitumor effect of TSA in ABC-1, NCI-H460 (H460) and A549 cells. Second, we investigated whether the effects of genistein are associated with increased histone/non-histone protein acetylation. We found that the enhancing effect of genistein on cell-growth-arrest in ABC-1 cells (p53 mutant) was less than in A549 and H460 cells. Genistein enhancedmore » TSA induced apoptosis in A549 and H460 cells rather than in ABC-1 cells. After silencing p53 expression in A549 and H460 cells, the enhancing effect of genistein was diminished. In addition, genistein increased TSA-induced histone H3/H4 acetylation in A549 and H460 cells. Genistein also increased p53 acetylation in H460 cells. The inhibitor of acetyltransferase, anacardic acid, diminished the enhancing effect of genistein on all TSA-induced histone/p53 acetylation and apoptosis. Genistein in combination with TSA increased the expression of p300 protein, an acetyltransferase, in A549 and NCI-H460 cells. Furthermore, we demonstrated that genistein also enhanced the antitumor effect of genistein in A549-tumor-bearing mice. Taken together, these results suggest that the enhancing effects of genistein on TSA-induced apoptosis in lung cancer cells were p53-dependent and were associated with histone/non-histone protein acetylation. - Highlights: • Genistein enhances the antitumor effect of TSA through p53-associated pathways. • Genistein enhances TSA-induced histone acetylation commonly. • An acetyltransferase inhibitor diminishes the antitumor effect of genistein + TSA. • TSA in combination with genistein increases the expression of p300. • Genistein given by i.p. injection increases the antitumor effect of TSA in vivo.« less

Serum albumin promotes ATP-binding cassette transporter-dependent sterol uptake in yeast.

PubMed

Marek, Magdalena; Silvestro, Daniele; Fredslund, Maria D; Andersen, Tonni G; Pomorski, Thomas G

2014-12-01

Sterol uptake in fungi is a multistep process that involves interaction between external sterols and the cell wall, incorporation of sterol molecules into the plasma membrane, and subsequent integration into intracellular membranes for turnover. ATP-binding cassette (ABC) transporters have been implicated in sterol uptake, but key features of their activity remain to be elucidated. Here, we apply fluorescent cholesterol (NBD-cholesterol) to monitor sterol uptake under anaerobic and aerobic conditions in two fungal species, Candida glabrata (Cg) and Saccharomyces cerevisiae (Sc). We found that in both fungal species, ABC transporter-dependent uptake of cholesterol under anaerobic conditions and in mutants lacking HEM1 gene is promoted in the presence of the serum protein albumin that is able to bind the sterol molecule. Furthermore, the C. glabrata ABC transporter CgAus1p expressed in S. cerevisiae requires the presence of serum or albumin for efficient cholesterol uptake. These results suggest that albumin can serve as sterol donor in ABC transporter-dependent sterol uptake, a process potentially important for growth of C. glabrata inside infected humans. © 2014 The Authors. FEMS Yeast Research published by John Wiley & Sons Ltd on behalf of Federation of European Microbiological Societies.

The Approximate Bayesian Computation methods in the localization of the atmospheric contamination source

NASA Astrophysics Data System (ADS)

Kopka, P.; Wawrzynczak, A.; Borysiewicz, M.

2015-09-01

In many areas of application, a central problem is a solution to the inverse problem, especially estimation of the unknown model parameters to model the underlying dynamics of a physical system precisely. In this situation, the Bayesian inference is a powerful tool to combine observed data with prior knowledge to gain the probability distribution of searched parameters. We have applied the modern methodology named Sequential Approximate Bayesian Computation (S-ABC) to the problem of tracing the atmospheric contaminant source. The ABC is technique commonly used in the Bayesian analysis of complex models and dynamic system. Sequential methods can significantly increase the efficiency of the ABC. In the presented algorithm, the input data are the on-line arriving concentrations of released substance registered by distributed sensor network from OVER-LAND ATMOSPHERIC DISPERSION (OLAD) experiment. The algorithm output are the probability distributions of a contamination source parameters i.e. its particular location, release rate, speed and direction of the movement, start time and duration. The stochastic approach presented in this paper is completely general and can be used in other fields where the parameters of the model bet fitted to the observable data should be found.

The importance of activity-based methods in radiology and the technology that now makes this possible.

PubMed

Monge, Paul

2006-01-01

Activity-based methods serve as a dynamic process that has allowed many other industries to reduce and control their costs, increase productivity, and streamline their processes while improving product quality and service. The method could serve the healthcare industry in an equally beneficial way. Activity-based methods encompass both activity based costing (ABC) and activity-based management (ABM). ABC is a cost management approach that links resource consumption to activities that an enterprise performs, and then assigns those activities and their associated costs to customers, products, or product lines. ABM uses the resource assignments derived in ABC so that operation managers can improve their departmental processes and workflows. There are three fundamental problems with traditional cost systems. First, traditional systems fail to reflect the underlying diversity of work taking place within an enterprise. Second, it uses allocations that are, for the most part, arbitrary Single step allocations fail to reflect the real work-the activities being performed and the associate resources actually consumed. Third, they only provide a cost number that, standing alone, does not provide any guidance on how to improve performance by lowering cost or enhancing throughput.

Dolutegravir Plus Two Nucleoside Reverse Transcriptase Inhibitors versus Efavirenz Plus Two Nucleoside Reverse Transcriptase Inhibitors As Initial Antiretroviral Therapy for People with HIV: A Systematic Review.

PubMed

Rutherford, George W; Horvath, Hacsi

2016-01-01

Dolutegravir (DTG) is a once-daily unboosted second-generation integrase-inhibitor that along with two nucleoside reverse transcriptase inhibitors is one of several regimens recommended by the United States, United Kingdom and European Union for first-line antiretroviral treatment of people with HIV infection. Our objective was to review the evidence for the efficacy and safety of DTG-based first-line regimens compared to efavirenz (EFV)-based regimens. We conducted a systematic review. We comprehensively searched a range of databases as well as conference abstracts and a trials registry. We used Cochrane methods in screening and data collection and assessed each study's risk of bias with the Cochrane tool. We meta-analyzed data using a fixed-effects model. We used GRADE to assess evidence quality. From 492 search results, we identified two randomized controlled trials, reported in five peer-reviewed articles and one conference abstract. One trial tested two DTG-based regimens (DTG + abacavir (ABC) + lamivudine (3TC) or DTG + tenofovir + emtricitabine) against an EFV-based regimen (EFV+ ABC+3TC). The other trial tested DTG+ABC+3TC against EFV+ABC+3TC. In meta-analysis, DTG-containing regimens were superior to EFV-containing regimens at 48 weeks and at 96 weeks (RR = 1.10, 95% CI 1.04-1.16; and RR = 1.12, 95% CI 1.04-1.21, respectively). In one trial, the DTG-containing regimen was superior at 144 weeks (RR = 1.13, 95% CI 1.02-1.24). DTG-containing regimens were superior in reducing treatment discontinuation compared to those containing EFV at 96 weeks and at 144 weeks (RR = 0.27, 95% CI 0.15-0.50; and RR = 0.28, 95% CI 0.16-0.48, respectively). Risk of serious adverse events was similar in each regimen at 96 weeks (RR = 1.15, 95% CI 0.80-1.63) and 144 weeks (RR = 0.93, 95% CI 0.68-1.29). Risk of bias was moderate overall, as was GRADE evidence quality. DTG-based regimens should be considered in future World Health Organization guidelines for initial HIV treatment.

ROLE OF ATP BINDING CASSETTE SUB-FAMILY MEMBER 2 (ABCG2) IN MOUSE EMBRYONIC STEM CELL DEVELOPMENT.

EPA Science Inventory

ATP binding cassette sub-family member 2 (ABCG2), is a member of the ABC transporter superfamily and a principal xenobiotic transporter. ABCG2 is also highly expressed in certain stem cell populations where it is thought to be related to stem cell plasticity, although the role o...

Kalkipyrone B, a marine cyanobacterial γ-pyrone possessing cytotoxic and anti-fungal activities

PubMed Central

Bertin, Matthew J; Demirkiran, Ozlem; Navarro, Gabriel; Moss, Nathan A; Lee, John; Goldgof, Gregory M; Vigil, Edgar; Winzeler, Elizabeth A; Valeriote, Fred A; Gerwick, William H

2015-01-01

Bioassay-guided fractionation of two marine cyanobacterial extracts using the H-460 human lung cancer cell line and the OVC-5 human ovarian cancer cell line led to the isolation of three related α-methoxy-β, β’-dimethyl-γ-pyrones each containing a modified alkyl chain, one of which was identified as the previously reported kalkipyrone and designated kalkipyrone A. The second compound was an analog designated kalkipyrone B. The third was identified as the recently reported yoshipyrone A, also isolated from a marine cyanobacterium. Kalkipyrone A and B were obtained from a field-collection of the cyanobacterium Leptolyngbya sp. from Fagasa Bay, American Samoa, while yoshipyrone A was isolated from a field-collection of cyanobacteria (cf. Schizothrix sp.) from Panama. One-dimensional and two-dimensional NMR experiments were used to determine the overall structures and relative configurations of the kalkipyrones, and the absolute configuration of kalkipyrone B was determined by 1H NMR analysis of diastereomeric Mosher’s esters. Kalkipyrone A showed good cytotoxicity to H-460 human lung cancer cells (EC50 = 0.9 µM), w M), while kalkipyrone B and yoshipyrone A were less active (EC50 = 9.0 µM and > 10 µM, respectively). Both kalkipyrone A and B showed moderate toxicity to Saccharomyces cerevisiae ABC16-Monster strain (IC50 = 14.6 and 13.4 µM, respectively), whereas yoshipyrone A was of low toxicity to this yeast strain (IC50 = 63.8 µM). PMID:26632528

Neratinib reverses ATP-binding cassette B1-mediated chemotherapeutic drug resistance in vitro, in vivo, and ex vivo.

PubMed

Zhao, Xiao-qin; Xie, Jing-dun; Chen, Xing-gui; Sim, Hong May; Zhang, Xu; Liang, Yong-ju; Singh, Satyakam; Talele, Tanaji T; Sun, Yueli; Ambudkar, Suresh V; Chen, Zhe-Sheng; Fu, Li-wu

2012-07-01

Neratinib, an irreversible inhibitor of epidermal growth factor receptor and human epidermal receptor 2, is in phase III clinical trials for patients with human epidermal receptor 2-positive, locally advanced or metastatic breast cancer. The objective of this study was to explore the ability of neratinib to reverse tumor multidrug resistance attributable to overexpression of ATP-binding cassette (ABC) transporters. Our results showed that neratinib remarkably enhanced the sensitivity of ABCB1-overexpressing cells to ABCB1 substrates. It is noteworthy that neratinib augmented the effect of chemotherapeutic agents in inhibiting the growth of ABCB1-overexpressing primary leukemia blasts and KBv200 cell xenografts in nude mice. Furthermore, neratinib increased doxorubicin accumulation in ABCB1-overexpressing cell lines and Rhodamine 123 accumulation in ABCB1-overexpressing cell lines and primary leukemia blasts. Neratinib stimulated the ATPase activity of ABCB1 at low concentrations but inhibited it at high concentrations. Likewise, neratinib inhibited the photolabeling of ABCB1 with [(125)I]iodoarylazidoprazosin in a concentration-dependent manner (IC(50) = 0.24 μM). Neither the expression of ABCB1 at the mRNA and protein levels nor the phosphorylation of Akt was affected by neratinib at reversal concentrations. Docking simulation results were consistent with the binding conformation of neratinib within the large cavity of the transmembrane region of ABCB1, which provides computational support for the cross-reactivity of tyrosine kinase inhibitors with human ABCB1. In conclusion, neratinib can reverse ABCB1-mediated multidrug resistance in vitro, ex vivo, and in vivo by inhibiting its transport function.

Neratinib Reverses ATP-Binding Cassette B1-Mediated Chemotherapeutic Drug Resistance In Vitro, In Vivo, and Ex Vivo

PubMed Central

Zhao, Xiao-qin; Xie, Jing-dun; Chen, Xing-gui; Sim, Hong May; Zhang, Xu; Liang, Yong-ju; Singh, Satyakam; Talele, Tanaji T.; Sun, Yueli; Ambudkar, Suresh V.; Chen, Zhe-Sheng

2012-01-01

Neratinib, an irreversible inhibitor of epidermal growth factor receptor and human epidermal receptor 2, is in phase III clinical trials for patients with human epidermal receptor 2-positive, locally advanced or metastatic breast cancer. The objective of this study was to explore the ability of neratinib to reverse tumor multidrug resistance attributable to overexpression of ATP-binding cassette (ABC) transporters. Our results showed that neratinib remarkably enhanced the sensitivity of ABCB1-overexpressing cells to ABCB1 substrates. It is noteworthy that neratinib augmented the effect of chemotherapeutic agents in inhibiting the growth of ABCB1-overexpressing primary leukemia blasts and KBv200 cell xenografts in nude mice. Furthermore, neratinib increased doxorubicin accumulation in ABCB1-overexpressing cell lines and Rhodamine 123 accumulation in ABCB1-overexpressing cell lines and primary leukemia blasts. Neratinib stimulated the ATPase activity of ABCB1 at low concentrations but inhibited it at high concentrations. Likewise, neratinib inhibited the photolabeling of ABCB1 with [125I]iodoarylazidoprazosin in a concentration-dependent manner (IC50 = 0.24 μM). Neither the expression of ABCB1 at the mRNA and protein levels nor the phosphorylation of Akt was affected by neratinib at reversal concentrations. Docking simulation results were consistent with the binding conformation of neratinib within the large cavity of the transmembrane region of ABCB1, which provides computational support for the cross-reactivity of tyrosine kinase inhibitors with human ABCB1. In conclusion, neratinib can reverse ABCB1-mediated multidrug resistance in vitro, ex vivo, and in vivo by inhibiting its transport function. PMID:22491935

Controlling transgene expression in subcutaneous implants using a skin lotion containing the apple metabolite phloretin.

PubMed

Gitzinger, Marc; Kemmer, Christian; El-Baba, Marie Daoud; Weber, Wilfried; Fussenegger, Martin

2009-06-30

Adjustable control of therapeutic transgenes in engineered cell implants after transdermal and topical delivery of nontoxic trigger molecules would increase convenience, patient compliance, and elimination of hepatic first-pass effect in future therapies. Pseudomonas putida DOT-T1E has evolved the flavonoid-triggered TtgR operon, which controls expression of a multisubstrate-specific efflux pump (TtgABC) to resist plant-derived defense metabolites in its rhizosphere habitat. Taking advantage of the TtgR operon, we have engineered a hybrid P. putida-mammalian genetic unit responsive to phloretin. This flavonoid is contained in apples, and, as such, or as dietary supplement, regularly consumed by humans. The engineered mammalian phloretin-adjustable control element (PEACE) enabled adjustable and reversible transgene expression in different mammalian cell lines and primary cells. Due to the short half-life of phloretin in culture, PEACE could also be used to program expression of difficult-to-produce protein therapeutics during standard bioreactor operation. When formulated in skin lotions and applied to the skin of mice harboring transgenic cell implants, phloretin was able to fine-tune target genes and adjust heterologous protein levels in the bloodstream of treated mice. PEACE-controlled target gene expression could foster advances in biopharmaceutical manufacturing as well as gene- and cell-based therapies.

Controlling transgene expression in subcutaneous implants using a skin lotion containing the apple metabolite phloretin

PubMed Central

Gitzinger, Marc; Kemmer, Christian; El-Baba, Marie Daoud; Weber, Wilfried; Fussenegger, Martin

2009-01-01

Adjustable control of therapeutic transgenes in engineered cell implants after transdermal and topical delivery of nontoxic trigger molecules would increase convenience, patient compliance, and elimination of hepatic first-pass effect in future therapies. Pseudomonas putida DOT-T1E has evolved the flavonoid-triggered TtgR operon, which controls expression of a multisubstrate-specific efflux pump (TtgABC) to resist plant-derived defense metabolites in its rhizosphere habitat. Taking advantage of the TtgR operon, we have engineered a hybrid P. putida–mammalian genetic unit responsive to phloretin. This flavonoid is contained in apples, and, as such, or as dietary supplement, regularly consumed by humans. The engineered mammalian phloretin-adjustable control element (PEACE) enabled adjustable and reversible transgene expression in different mammalian cell lines and primary cells. Due to the short half-life of phloretin in culture, PEACE could also be used to program expression of difficult-to-produce protein therapeutics during standard bioreactor operation. When formulated in skin lotions and applied to the skin of mice harboring transgenic cell implants, phloretin was able to fine-tune target genes and adjust heterologous protein levels in the bloodstream of treated mice. PEACE-controlled target gene expression could foster advances in biopharmaceutical manufacturing as well as gene- and cell-based therapies. PMID:19549857

Absorption of Deuterium Fluoride Laser Radiation by the Atmosphere

DTIC Science & Technology

1976-04-01

30 lines, and it would have been prohibitively costly in terms of time and money to measure the ab- sorption on all lines. McClatchey, et al.[3...linear molecule (N2O, CO2, CO) Herzberg [5] gives as an approximation 14 ^ Vi ~_ i’: (45) so that (47) qR(T) hcB V. (ln\\ 1.0 For asymmetric...top molecules (H20, 03) Herzberg [5] gives as an approximation (48) so that ABC \\hc; (49) ±-^f) For spherical top molecules (CH4) Herzberg [5

Both cell fusion and transdifferentiation account for the transformation of human peripheral blood CD34-positive cells into cardiomyocytes in vivo.

PubMed

Zhang, Sui; Wang, Dachun; Estrov, Zeev; Raj, Sean; Willerson, James T; Yeh, Edward T H

2004-12-21

Adult human peripheral blood CD34-positive (CD34+) cells appear to transform into cardiomyocytes in the injured hearts of severe combined immunodeficient mice. It remains unclear, however, whether the apparent transformation is the result of transdifferentiation of the donor stem cells or of fusion of the donor cell with the cardiomyocyte of the recipients. We performed flow cytometry analyses of cells isolated from the hearts of mice that received human CD34+ cells. Human HLA-ABC antigen and cardiac troponin T or Nkx2.5 were used as markers for cardiomyocytes derived from human CD34+ cells, and HLA-ABC and VE-cadherin were used to identify the transformed endothelial cells. The double-positive cells were collected and interphase fluorescence in situ hybridization was used to detect the expression of human and mouse X chromosomes in these cells. We found that 73.3% of nuclei derived from HLA+ and troponin T+ or Nkx2.5+ cardiomyocytes contain both human and mouse X chromosomes and 23.7% contain only human X chromosome. In contrast, the nuclei of HLA-, troponin T+ cells contain only mouse X chromosomes. Furthermore, 97.3% of endothelial cells derived from CD34+ cells contained human X chromosome only. Thus, both cell fusion and transdifferentiation may account for the transformation of peripheral blood CD34+ cells into cardiomyocytes in vivo.

Mechanistic Study of Utilization of Water-Insoluble Saccharomyces cerevisiae Glucans by Bifidobacterium breve Strain JCM1192

PubMed Central

Keung, Hoi Yee; Li, Tsz Kai; Sham, Lok To; Cheung, Man Kit; Cheung, Peter Chi Keung

2017-01-01

ABSTRACT Bifidobacteria exert beneficial effects on hosts and are extensively used as probiotics. However, due to the genetic inaccessibility of these bacteria, little is known about their mechanisms of carbohydrate utilization and regulation. Bifidobacterium breve strain JCM1192 can grow on water-insoluble yeast (Saccharomyces cerevisiae) cell wall glucans (YCWG), which were recently considered as potential prebiotics. According to the results of 1H nuclear magnetic resonance (NMR) spectrometry, the YCWG were composed of highly branched (1→3,1→6)-β-glucans and (1→4,1→6)-α-glucans. Although the YCWG were composed of 78.3% β-glucans and 21.7% α-glucans, only α-glucans were consumed by the B. breve strain. The ABC transporter (malEFG1) and pullulanase (aapA) genes were transcriptionally upregulated in the metabolism of insoluble yeast glucans, suggesting their potential involvement in the process. A nonsense mutation identified in the gene encoding an ABC transporter ATP-binding protein (MalK) led to growth failure of an ethyl methanesulfonate-generated mutant with yeast glucans. Coculture of the wild-type strain and the mutant showed that this protein was responsible for the import of yeast glucans or their breakdown products, rather than the export of α-glucan-catabolizing enzymes. Further characterization of the carbohydrate utilization of the mutant and three of its revertants indicated that this mutation was pleiotropic: the mutant could not grow with maltose, glycogen, dextrin, raffinose, cellobiose, melibiose, or turanose. We propose that insoluble yeast α-glucans are hydrolyzed by extracellular pullulanase into maltose and/or maltooligosaccharides, which are then transported into the cell by the ABC transport system composed of MalEFG1 and MalK. The mechanism elucidated here will facilitate the development of B. breve and water-insoluble yeast glucans as novel synbiotics. IMPORTANCE In general, Bifidobacterium strains are genetically intractable. Coupling classic forward genetics with next-generation sequencing, here we identified an ABC transporter ATP-binding protein (MalK) responsible for the import of insoluble yeast glucan breakdown products by B. breve JCM1192. We demonstrated the pleiotropic effects of the ABC transporter ATP-binding protein in maltose/maltooligosaccharide, raffinose, cellobiose, melibiose, and turanose transport. With the addition of transcriptional analysis, we propose that insoluble yeast glucans are broken down by extracellular pullulanase into maltose and/or maltooligosaccharides, which are then transported into the cell by the ABC transport system composed of MalEFG1 and MalK. The mechanism elucidated here will facilitate the development of B. breve and water-insoluble yeast glucans as novel synbiotics. PMID:28115383

Mechanistic Study of Utilization of Water-Insoluble Saccharomyces cerevisiae Glucans by Bifidobacterium breve Strain JCM1192.

PubMed

Keung, Hoi Yee; Li, Tsz Kai; Sham, Lok To; Cheung, Man Kit; Cheung, Peter Chi Keung; Kwan, Hoi Shan

2017-04-01

Bifidobacteria exert beneficial effects on hosts and are extensively used as probiotics. However, due to the genetic inaccessibility of these bacteria, little is known about their mechanisms of carbohydrate utilization and regulation. Bifidobacterium breve strain JCM1192 can grow on water-insoluble yeast ( Saccharomyces cerevisiae ) cell wall glucans (YCWG), which were recently considered as potential prebiotics. According to the results of 1 H nuclear magnetic resonance (NMR) spectrometry, the YCWG were composed of highly branched (1→3,1→6)-β-glucans and (1→4,1→6)-α-glucans. Although the YCWG were composed of 78.3% β-glucans and 21.7% α-glucans, only α-glucans were consumed by the B. breve strain. The ABC transporter ( malEFG1 ) and pullulanase ( aapA ) genes were transcriptionally upregulated in the metabolism of insoluble yeast glucans, suggesting their potential involvement in the process. A nonsense mutation identified in the gene encoding an ABC transporter ATP-binding protein (MalK) led to growth failure of an ethyl methanesulfonate-generated mutant with yeast glucans. Coculture of the wild-type strain and the mutant showed that this protein was responsible for the import of yeast glucans or their breakdown products, rather than the export of α-glucan-catabolizing enzymes. Further characterization of the carbohydrate utilization of the mutant and three of its revertants indicated that this mutation was pleiotropic: the mutant could not grow with maltose, glycogen, dextrin, raffinose, cellobiose, melibiose, or turanose. We propose that insoluble yeast α-glucans are hydrolyzed by extracellular pullulanase into maltose and/or maltooligosaccharides, which are then transported into the cell by the ABC transport system composed of MalEFG1 and MalK. The mechanism elucidated here will facilitate the development of B. breve and water-insoluble yeast glucans as novel synbiotics. IMPORTANCE In general, Bifidobacterium strains are genetically intractable. Coupling classic forward genetics with next-generation sequencing, here we identified an ABC transporter ATP-binding protein (MalK) responsible for the import of insoluble yeast glucan breakdown products by B. breve JCM1192. We demonstrated the pleiotropic effects of the ABC transporter ATP-binding protein in maltose/maltooligosaccharide, raffinose, cellobiose, melibiose, and turanose transport. With the addition of transcriptional analysis, we propose that insoluble yeast glucans are broken down by extracellular pullulanase into maltose and/or maltooligosaccharides, which are then transported into the cell by the ABC transport system composed of MalEFG1 and MalK. The mechanism elucidated here will facilitate the development of B. breve and water-insoluble yeast glucans as novel synbiotics. Copyright © 2017 American Society for Microbiology.

Chromospherically active stars. 12: ADS 11060 C: A double lined K dwarf binary in a quintuple system

NASA Technical Reports Server (NTRS)

Fekel, Francis C.; Henry, Gregory W.; Hampton, Melissa L.; Fried, Robert; Morton, Mary D.

1994-01-01

ADS 11060 C is a double lined spectroscopic binary with a period of 25.7631 days and an eccentricity of 0.565. Spectral types of the two stars are estimated as K7 V and MO V with a magnitude difference of about 0.55 mag in V. The stars appear to be somewhat metal rich with respect to the Sun. Despite the relatively large masses of 0.53 and 0.51 solar mass, our photometric observations find no evidence for eclipses and we estimate an inclination of 77 deg plus or minus 11 deg. ADS 11060 C is, however, photometrically variable with a period of 9 plus or minus 1 day and an amplitude of 0.05 mag in V. Thus, it is a newly identified BY Draconis variable. The center-of-mass velocity of ADS 11060 C and an estimated parallax of 0.030 sec support its physical association with ADS 11060 AB, making this a quintuple system. The projected separation of the AB-C system is nearly 1200 AU. Although the log lithium abundances of the two components of ADS 11060 C are only upper limits, less than or equal to -0.14, lithium abundances of the AB-C components appear to be consistent with those of similar stars in the alpha Persei and Pleiades clusters, suggesting an age of about 70 Myr for ADS 11060 AB-C. The system is a possible member of the Pleiades moving group. Listed as an optical counterpart to a source in the ROSAT Wide Field Camera extreme-ultraviolet bright source catalog, both ADS 11060 AB and C may contribute to the observed flux.

Basket Study of Entrectinib (RXDX-101) for the Treatment of Patients With Solid Tumors Harboring NTRK 1/2/3 (Trk A/B/C), ROS1, or ALK Gene Rearrangements (Fusions)

ClinicalTrials.gov

2018-06-13

Breast Cancer; Cholangiocarcinoma; Colorectal Cancer; Head and Neck Neoplasms; Lymphoma, Large-Cell, Anaplastic; Melanoma; Neuroendocrine Tumors; Non-Small Cell Lung Cancer; Ovarian Cancer; Pancreatic Cancer; Papillary Thyroid Cancer; Primary Brain Tumors; Renal Cell Carcinoma; Sarcomas; Salivary Gland Cancers; Adult Solid Tumor

Identification of ABC Transporter Genes of Fusarium graminearum with Roles in Azole Tolerance and/or Virulence

PubMed Central

Döll, Katharina; Karlovsky, Petr; Deising, Holger B.; Wirsel, Stefan G. R.

2013-01-01

Fusarium graminearum is a plant pathogen infecting several important cereals, resulting in substantial yield losses and mycotoxin contamination of the grain. Triazole fungicides are used to control diseases caused by this fungus on a worldwide scale. Our previous microarray study indicated that 15 ABC transporter genes were transcriptionally upregulated in response to tebuconazole treatment. Here, we deleted four ABC transporter genes in two genetic backgrounds of F. graminearum representing the DON (deoxynivalenol) and the NIV (nivalenol) trichothecene chemotypes. Deletion of FgABC3 and FgABC4 belonging to group I of ABC-G and to group V of ABC-C subfamilies of ABC transporters, respectively, considerably increased the sensitivity to the class I sterol biosynthesis inhibitors triazoles and fenarimol. Such effects were specific since they did not occur with any other fungicide class tested. Assessing the contribution of the four ABC transporters to virulence of F. graminearum revealed that, irrespective of their chemotypes, deletion mutants of FgABC1 (ABC-C subfamily group V) and FgABC3 were impeded in virulence on wheat, barley and maize. Phylogenetic context and analyses of mycotoxin production suggests that FgABC3 may encode a transporter protecting the fungus from host-derived antifungal molecules. In contrast, FgABC1 may encode a transporter responsible for the secretion of fungal secondary metabolites alleviating defence of the host. Our results show that ABC transporters play important and diverse roles in both fungicide resistance and pathogenesis of F. graminearum. PMID:24244413

Discovering non-random segregation of sister chromatids: the naïve treatment of a premature discovery

PubMed Central

Lark, Karl G.

2013-01-01

The discovery of non-random chromosome segregation (Figure 1) is discussed from the perspective of what was known in 1965 and 1966. The distinction between daughter, parent, or grandparent strands of DNA was developed in a bacterial system and led to the discovery that multiple copies of DNA elements of bacteria are not distributed randomly with respect to the age of the template strand. Experiments with higher eukaryotic cells demonstrated that during mitosis Mendel’s laws were violated; and the initial serendipitous choice of eukaryotic cell system led to the striking example of non-random segregation of parent and grandparent DNA template strands in primary cultures of cells derived from mouse embryos. Attempts to extrapolate these findings to established tissue culture lines demonstrated that the property could be lost. Experiments using plant root tips demonstrated that the phenomenon exists in plants and that it was, at some level, under genetic control. Despite publication in major journals and symposia (Lark et al., 1966, 1967; Lark, 1967, 1969a,b,c) the potential implications of these findings were ignored for several decades. Here we explore possible reasons for the pre-maturity (Stent, 1972) of this discovery. PMID:23378946

Dual system to reinforce biological containment of recombinant bacteria designed for rhizoremediation.

PubMed

Ronchel, M C; Ramos, J L

2001-06-01

Active biological containment (ABC) systems have been designed to control at will the survival or death of a bacterial population. These systems are based on the use of a killing gene, e.g., a porin-inducing protein such as the one encoded by the Escherichia coli gef gene, and a regulatory circuit that controls expression of the killing gene in response to the presence or absence of environmental signals. An ABC system for recombinant microorganisms that degrade a model pollutant was designed on the basis of the Pseudomonas putida TOL plasmid meta-cleavage regulatory circuit. The system consists of a fusion of the Pm promoter to lacI, whose expression is controlled by XylS with 3-methylbenzoate, and a fusion of a synthetic P(lac) promoter to gef. In the presence of the model pollutant, bacterial cells survived and degraded the target compound, whereas in the absence of the aromatic carboxylic acid cell death was induced. The system had two main drawbacks: (i) the slow death of the bacterial cells in soil versus the fast killing rate in liquid cultures in laboratory assays, and (ii) the appearance of mutants, at a rate of about 10(-8) per cell and generation, that did not die after the pollutant had been exhausted. We reinforced the ABC system by including it in a Deltaasd P. putida background. A P. putida Deltaasd mutant is viable only in complex medium supplemented with diaminopimelic acid, methionine, lysine, and threonine. We constructed a P. putida Deltaasd strain, called MCR7, with a Pm::asd fusion in the host chromosome. This strain was viable in the presence of 3-methylbenzoate because synthesis of the essential metabolites was achieved through XylS-dependent induction. In the P. putida MCR7 strain, an ABC system (Pm::lacI, xylS, P(lac)::gef) was incorporated into the host chromosome to yield strain MCR8. The number of MCR8 mutants that escaped killing was below our detection limit (<10(-9) mutants per cell and generation). The MCR8 strain survived and colonized rhizosphere soil with 3-methylbenzoate at a level similar to that of the wild-type strain. However, it disappeared in less than 20 to 25 days in soils without the pollutant, whereas an asd(+), biologically contained counterpart such as P. putida CMC4 was still detectable in soils after 100 days.

AST1306, a potent EGFR inhibitor, antagonizes ATP-binding cassette subfamily G member 2-mediated multidrug resistance.

PubMed

Zhang, Hui; Wang, Yi-Jun; Zhang, Yun-Kai; Wang, De-Shen; Kathawala, Rishil J; Patel, Atish; Talele, Tanaji T; Chen, Zhe-Sheng; Fu, Li-Wu

2014-08-01

AST1306, an inhibitor of EGFR and ErbB2, is currently in phase I of clinical trials. We evaluated the effect of AST306 on the reversal of multidrug resistance (MDR) induced by ATP-binding cassette (ABC) transporters. We found that AST1306 significantly sensitized the ABC subfamily G member 2 (ABCG2)-overexpressing cells to ABCG2 substrate chemotherapeutics. AST1306 significantly increased intracellular accumulation of [(3)H]-mitoxantrone in ABCG2-overexpressing cells by blocking ABCG2 efflux function. Moreover, AST1306 stimulated the ATPase activity of ABCG2. Homology modeling predicted the binding conformation of AST1306 to be within the transmembrane region of ABCG2. In conclusion, AST1306 could notably reverse ABCG2-mediated MDR. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Celecoxib sensitizes imatinib-resistant K562 cells to imatinib by inhibiting MRP1-5, ABCA2 and ABCG2 transporters via Wnt and Ras signaling pathways.

PubMed

Dharmapuri, Gangappa; Doneti, Ravinder; Philip, Gundala Harold; Kalle, Arunasree M

2015-07-01

Imatinib mesylate, a tyrosine kinase inhibitor, is very effective in the treatment of chronic myeloid leukemia (CML). However, development of resistance to imatinib therapy is also a very common mechanism observed with long-term administration of the drug. Our previous studies have highlighted the role of cyclooxygenase-2 (COX-2) in regulating the expression of multidrug resistant protein-1 (MDR1), P-gp, in imatinib-resistant K562 cells (IR-K562) via PGE2-cAMP-PKC-NF-κB pathway and inhibition of COX-2 by celecoxib, a COX-2 specific inhibitor, inhibits this pathway and reverses the drug resistance. Studies have identified that not only MDR1 but other ATP-binding cassette transport proteins (ABC transporters) are involved in the development of imatinib resistance. Here, we tried to study the role of COX-2 in the regulation of other ABC transporters such as MRP1, MRP2, MRP3, ABCA2 and ABCG2 that have been already implicated in imatinib resistance development. The results of the study clearly indicated that overexpression of COX-2 lead to upregulation of MRP family proteins in IR-K562 cells and celecoxib down-regulated the ABC transporters through Wnt and MEK signaling pathways. The study signifies that celecoxib in combination with the imatinib can be a good alternate treatment strategy for the reversal of imatinib resistance. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis of amide isosteres of schweinfurthin-based stilbenes.

PubMed

Stockdale, David P; Beutler, John A; Wiemer, David F

2017-10-15

The schweinfurthins are plant-derived stilbenes with an intriguing profile of anti-cancer activity. To obtain analogues of the schweinfurthins that might preserve the biological activity but have greater water solubility, a formal replacement of the central olefin with an amide has been explored. Two pairs of amides have been prepared, each containing the same hexahydroxanthene "left half" joined through an amide linkage to two different "right halves." In each series, the amide has been inserted in both possible orientations, placing the carbonyl group on the tricyclic ABC ring system and the amine on the D-ring, or placing the amine on the hexahydroxanthene and the carbonyl group on the D-ring. The four new schweinfurthin analogues have been tested in the NCI 60 cell line screen, and in both cases the more active isomer carried the carbonyl group on the C-ring. Copyright © 2017 Elsevier Ltd. All rights reserved.

Amino Acid Transporters and Release of Hydrophobic Amino Acids in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120.

PubMed

Pernil, Rafael; Picossi, Silvia; Herrero, Antonia; Flores, Enrique; Mariscal, Vicente

2015-04-23

Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can use inorganic compounds such as nitrate or ammonium as nitrogen sources. In the absence of combined nitrogen, it can fix N2 in differentiated cells called heterocysts. Anabaena also shows substantial activities of amino acid uptake, and three ABC-type transporters for amino acids have been previously characterized. Seven new loci encoding predicted amino acid transporters were identified in the Anabaena genomic sequence and inactivated. Two of them were involved in amino acid uptake. Locus alr2535-alr2541 encodes the elements of a hydrophobic amino acid ABC-type transporter that is mainly involved in the uptake of glycine. ORF all0342 encodes a putative transporter from the dicarboxylate/amino acid:cation symporter (DAACS) family whose inactivation resulted in an increased uptake of a broad range of amino acids. An assay to study amino acid release from Anabaena filaments to the external medium was set up. Net release of the alanine analogue α-aminoisobutyric acid (AIB) was observed when transport system N-I (a hydrophobic amino acid ABC-type transporter) was engaged in the uptake of a specific substrate. The rate of AIB release was directly proportional to the intracellular AIB concentration, suggesting leakage from the cells by diffusion.

MDR1 and BCRP Transporter-Mediated Drug-Drug Interaction between Rilpivirine and Abacavir and Effect on Intestinal Absorption

PubMed Central

Reznicek, Josef; Ceckova, Martina; Ptackova, Zuzana; Martinec, Ondrej; Tupova, Lenka; Cerveny, Lukas

2017-01-01

ABSTRACT Rilpivirine (TMC278) is a highly potent nonnucleoside reverse transcriptase inhibitor (NNRTI) representing an effective component of combination antiretroviral therapy (cART) in the treatment of HIV-positive patients. Many antiretroviral drugs commonly used in cART are substrates of ATP-binding cassette (ABC) and/or solute carrier (SLC) drug transporters and, therefore, are prone to pharmacokinetic drug-drug interactions (DDIs). The aim of our study was to evaluate rilpivirine interactions with abacavir and lamivudine on selected ABC and SLC transporters in vitro and assess its importance for pharmacokinetics in vivo. Using accumulation assays in MDCK cells overexpressing selected ABC or SLC drug transporters, we revealed rilpivirine as a potent inhibitor of MDR1 and BCRP, but not MRP2, OCT1, OCT2, or MATE1. Subsequent transport experiments across monolayers of MDCKII-MDR1, MDCKII-BCRP, and Caco-2 cells demonstrated that rilpivirine inhibits MDR1- and BCRP-mediated efflux of abacavir and increases its transmembrane transport. In vivo experiments in male Wistar rats confirmed inhibition of MDR1/BCRP in the small intestine, leading to a significant increase in oral bioavailability of abacavir. In conclusion, rilpivirine inhibits MDR1 and BCRP transporters and may affect pharmacokinetic behavior of concomitantly administered substrates of these transporters, such as abacavir. PMID:28696229

A phylogenomic analysis of the Actinomycetales mce operons

PubMed Central

Casali, Nicola; Riley, Lee W

2007-01-01

Background The genome of Mycobacterium tuberculosis harbors four copies of a cluster of genes termed mce operons. Despite extensive research that has demonstrated the importance of these operons on infection outcome, their physiological function remains obscure. Expanding databases of complete microbial genome sequences facilitate a comparative genomic approach that can provide valuable insight into the role of uncharacterized proteins. Results The M. tuberculosis mce loci each include two yrbE and six mce genes, which have homology to ABC transporter permeases and substrate-binding proteins, respectively. Operons with an identical structure were identified in all Mycobacterium species examined, as well as in five other Actinomycetales genera. Some of the Actinomycetales mce operons include an mkl gene, which encodes an ATPase resembling those of ABC uptake transporters. The phylogenetic profile of Mkl orthologs exactly matched that of the Mce and YrbE proteins. Through topology and motif analyses of YrbE homologs, we identified a region within the penultimate cytoplasmic loop that may serve as the site of interaction with the putative cognate Mkl ATPase. Homologs of the exported proteins encoded adjacent to the M. tuberculosis mce operons were detected in a conserved chromosomal location downstream of the majority of Actinomycetales operons. Operons containing linked mkl, yrbE and mce genes, resembling the classic organization of an ABC importer, were found to be common in Gram-negative bacteria and appear to be associated with changes in properties of the cell surface. Conclusion Evidence presented suggests that the mce operons of Actinomycetales species and related operons in Gram-negative bacteria encode a subfamily of ABC uptake transporters with a possible role in remodeling the cell envelope. PMID:17324287

Combination of Engineered Schwann Cell Grafts to Secrete Neurotrophin and Chondroitinase Promotes Axonal Regeneration and Locomotion after Spinal Cord Injury

PubMed Central

Pressman, Yelena; Moody, Alison; Berg, Randall; Muir, Elizabeth M.; Rogers, John H.; Ozawa, Hiroshi; Itoi, Eiji; Pearse, Damien D.; Bunge, Mary Bartlett

2014-01-01

Transplantation of Schwann cells (SCs) is a promising therapeutic strategy for spinal cord repair. SCs introduced into lesions support axon regeneration, but because these axons do not exit the transplant, additional approaches with SCs are needed. Here, we transplanted SCs genetically modified to secrete a bifunctional neurotrophin (D15A) and chondroitinase ABC (ChABC) into a subacute contusion injury in rats. We examined the effects of these modifications on graft volume, SC number, degradation of chondroitin sulfate proteoglycans (CSPGs), astrogliosis, SC myelination of axons, propriospinal and supraspinal axon numbers, locomotor outcome (BBB scoring, CatWalk gait analysis), and mechanical and thermal sensitivity on the hind paws. D15A secreted from transplanted SCs increased graft volume and SC number and myelinated axon number. SCs secreting ChABC significantly decreased CSPGs, led to some egress of SCs from the graft, and increased propriospinal and 5-HT-positive axons in the graft. SCs secreting both D15A and ChABC yielded the best responses: (1) the largest number of SC myelinated axons, (2) more propriospinal axons in the graft and host tissue around and caudal to it, (3) more corticospinal axons closer to the graft and around and caudal to it, (4) more brainstem neurons projecting caudal to the transplant, (5) increased 5-HT-positive axons in the graft and caudal to it, (6) significant improvement in aspects of locomotion, and (7) improvement in mechanical and thermal allodynia. This is the first evidence that the combination of SC transplants engineered to secrete neurotrophin and chondroitinase further improves axonal regeneration and locomotor and sensory function. PMID:24478364

Roles of Chondroitin Sulfate and Dermatan Sulfate in the Formation of a Lesion Scar and Axonal Regeneration after Traumatic Injury of the Mouse Brain

PubMed Central

Li, Hong-Peng; Komuta, Yukari; Kimura-Kuroda, Junko; van Kuppevelt, Toin H.

2013-01-01

Abstract Dermatan sulfate (DS) is synthesized from chondroitin sulfate (CS) by epimerization of glucuronic acid of CS to yield iduronic acid. In the present study, the role of CS and DS was examined in mice that received transection of nigrostriatal dopaminergic pathway followed by injection of glycosaminoglycan degrading enzymes into the lesion site. Two weeks after injury, fibrotic and glial scars were formed around the lesion, and transected axons did not regenerate beyond the fibrotic scar. Injection of chondroitinase ABC (ChABC), which degrades both CS and DS, completely suppressed the fibrotic scar formation, reduced the glial scar, and promoted the regeneration of dopaminergic axons. Injection of the DS-degrading enzyme chondroitinase B (ChB) also yielded similar results. By contrast, injection of chondroitinase AC (ChAC), a CS-degrading enzyme, did not suppress the fibrotic and glial scar formation, but reduced CS immunoreactivity and promoted the axonal regeneration. Addition of transforming growth factor-β1 (TGF-β1) to a co-culture of meningeal fibroblasts and cerebral astrocytes induces a fibrotic scar-like cell cluster. The effect of TGF-β1 on cluster formation was suppressed by treatment with ChABC or ChB, but not by ChAC. TGF-β1-induced cell cluster repelled neurites of neonatal cerebellar neurons, but addition of ChABC or ChAC suppressed the inhibitory property of clusters on neurite outgrowth. The present study is the first to demonstrate that DS and CS play different functions after brain injury: DS is involved in the lesion scar formation, and CS inhibits axonal regeneration. PMID:23438307

Influence of multidrug resistance and drug transport proteins on chemotherapy drug metabolism.

PubMed

Joyce, Helena; McCann, Andrew; Clynes, Martin; Larkin, Annemarie

2015-05-01

Chemotherapy involving the use of anticancer drugs remains an important strategy in the overall management of patients with metastatic cancer. Acquisition of multidrug resistance remains a major impediment to successful chemotherapy. Drug transporters in cell membranes and intracellular drug metabolizing enzymes contribute to the resistance phenotype and determine the pharmacokinetics of anticancer drugs in the body. ATP-binding cassette (ABC) transporters mediate the transport of endogenous metabolites and xenobiotics including cytotoxic drugs out of cells. Solute carrier (SLC) transporters mediate the influx of cytotoxic drugs into cells. This review focuses on the substrate interaction of these transporters, on their biology and what role they play together with drug metabolizing enzymes in eliminating therapeutic drugs from cells. The majority of anticancer drugs are substrates for the ABC transporter and SLC transporter families. Together, these proteins have the ability to control the influx and the efflux of structurally unrelated chemotherapeutic drugs, thereby modulating the intracellular drug concentration. These interactions have important clinical implications for chemotherapy because ultimately they determine therapeutic efficacy, disease progression/relapse and the success or failure of patient treatment.

Gyrotactic suppression and emergence of chaotic trajectories of swimming particles in three-dimensional flows

NASA Astrophysics Data System (ADS)

Richardson, S. I. Heath; Baggaley, A. W.; Hill, N. A.

2018-02-01

We study the effects of imposed three-dimensional flows on the trajectories and mixing of gyrotactic swimming microorganisms and identify phenomena not seen in flows restricted to two dimensions. Through numerical simulation of Taylor-Green and Arnold-Beltrami-Childress (ABC) flows, we explore the role that the flow and the cell shape play in determining the long-term configuration of the cells' trajectories, which often take the form of multiple sinuous and helical "plumelike" structures, even in the chaotic ABC flow. This gyrotactic suppression of Lagrangian chaos persists even in the presence of random noise. Analytical solutions for a number of cases reveal the how plumes form and the nature of the competition between torques acting on individual cells. Furthermore, studies of Lyapunov exponents reveal that, as the ratio of cell swimming speed relative to the flow speed increases from zero, the initial chaotic trajectories are first suppressed and then give way to a second unexpected window of chaotic trajectories at speeds greater than unity, before suppression of chaos at high relative swimming speeds.

Lévy flight artificial bee colony algorithm

NASA Astrophysics Data System (ADS)

Sharma, Harish; Bansal, Jagdish Chand; Arya, K. V.; Yang, Xin-She

2016-08-01

Artificial bee colony (ABC) optimisation algorithm is a relatively simple and recent population-based probabilistic approach for global optimisation. The solution search equation of ABC is significantly influenced by a random quantity which helps in exploration at the cost of exploitation of the search space. In the ABC, there is a high chance to skip the true solution due to its large step sizes. In order to balance between diversity and convergence in the ABC, a Lévy flight inspired search strategy is proposed and integrated with ABC. The proposed strategy is named as Lévy Flight ABC (LFABC) has both the local and global search capability simultaneously and can be achieved by tuning the Lévy flight parameters and thus automatically tuning the step sizes. In the LFABC, new solutions are generated around the best solution and it helps to enhance the exploitation capability of ABC. Furthermore, to improve the exploration capability, the numbers of scout bees are increased. The experiments on 20 test problems of different complexities and five real-world engineering optimisation problems show that the proposed strategy outperforms the basic ABC and recent variants of ABC, namely, Gbest-guided ABC, best-so-far ABC and modified ABC in most of the experiments.

Surface glycosaminoglycans mediate adherence between HeLa cells and Lactobacillus salivarius Lv72.

PubMed

Martín, Rebeca; Martín, Carla; Escobedo, Susana; Suárez, Juan E; Quirós, Luis M

2013-09-17

The adhesion of lactobacilli to the vaginal surface is of paramount importance to develop their probiotic functions. For this reason, the role of HeLa cell surface proteoglycans in the attachment of Lactobacillus salivarius Lv72, a mutualistic strain of vaginal origin, was investigated. Incubation of cultures with a variety of glycosaminoglycans (chondroitin sulfate A and C, heparin and heparan sulfate) resulted in marked binding interference. However, no single glycosaminoglycan was able to completely abolish cell binding, the sum of all having an additive effect that suggests cooperation between them and recognition of specific adhesins on the bacterial surface. In contrast, chondroitin sulfate B enhanced cell to cell attachment, showing the relevance of the stereochemistry of the uronic acid and the sulfation pattern on binding. Elimination of the HeLa surface glycosaminoglycans with lyases also resulted in severe adherence impairment. Advantage was taken of the Lactobacillus-glycosaminoglycans interaction to identify an adhesin from the bacterial surface. This protein, identify as a soluble binding protein of an ABC transporter system (OppA) by MALDI-TOF/(MS), was overproduced in Escherichia coli, purified and shown to interfere with L. salivarius Lv72 adhesion to HeLa cells. These data suggest that glycosaminoglycans play a fundamental role in attachment of mutualistic bacteria to the epithelium that lines the cavities where the normal microbiota thrives, OppA being a bacterial adhesin involved in the process.

Multiple resistance to carcinogens and xenobiotics: P-glycoproteins as universal detoxifiers.

PubMed

Efferth, Thomas; Volm, Manfred

2017-07-01

The detoxification of toxic substances is of general relevance in all biological systems. The plethora of exogenous xenobiotic compounds and endogenous toxic metabolic products explains the evolutionary pressure of all organisms to develop molecular mechanisms to detoxify and excrete harmful substances from the body. P-glycoprotein and other members of the ATP-binding cassette (ABC) transporter family extrude innumerous chemical compounds out of cells. Their specific expression in diverse biological contexts cause different phenotypes: (1) multidrug resistance (MDR) and thus failure of cancer chemotherapy, (2) avoidance of accumulation of carcinogens and prevention of carcinogenesis in healthy tissues, (3) absorption, distribution, metabolization and excretion (ADME) of pharmacological drugs in human patients, (4) protection from environmental toxins in aquatic organisms (multi-xenobiotic resistance, MXR). Hence ABC-transporters may have opposing effects for organismic health reaching from harmful in MDR of tumors to beneficial for maintenance of health in MXR. While their inhibition by specific inhibitors may improve treatment success in oncology and avoid carcinogenesis, blocking of ABC-transporter-driven efflux by environmental pollutants leads to ecotoxicological consequences in marine biotopes. Poisoned seafood may enter the food-chain and cause intoxications in human beings. As exemplified with ABC-transporters, joining forces in interdisciplinary research may, therefore, be a wise strategy to fight problems in human medicine and environmental sciences.

Structure of the MacAB-TolC ABC-type tripartite multidrug efflux pump

PubMed Central

Llabrés, Salomé; Neuberger, Arthur; Blaza, James N.; Bai, Xiao-chen; Okada, Ui; Murakami, Satoshi; van Veen, Hendrik W.; Zachariae, Ulrich; Scheres, Sjors H.W.; Luisi, Ben F.

2017-01-01

The MacA-MacB-TolC assembly of Escherichia coli is a transmembrane machine that spans the cell envelope and actively extrudes substrates, including macrolide antibiotics and polypeptide virulence factors. These transport processes are energized by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. We present an electron cryo-microscopy structure of the ABC-type tripartite assembly at near-atomic resolution. A hexamer of the periplasmic protein MacA bridges between a TolC trimer in the outer membrane and a MacB dimer in the inner membrane, generating a quaternary structure with a central channel for substrate translocation. A gating ring found in MacA is proposed to act as a one-way valve in substrate transport. The MacB structure features an atypical transmembrane domain (TMD) with a closely packed dimer interface and a periplasmic opening that is the likely portal for substrate entry from the periplasm, with subsequent displacement through an allosteric transport mechanism. PMID:28504659

Hfq Influences Multiple Transport Systems and Virulence in the Plant Pathogen Agrobacterium tumefaciens

PubMed Central

Wilms, Ina; Möller, Philip; Stock, Anna-Maria; Gurski, Rosemarie; Lai, Erh-Min

2012-01-01

The Hfq protein mediates gene regulation by small RNAs (sRNAs) in about 50% of all bacteria. Depending on the species, phenotypic defects of an hfq mutant range from mild to severe. Here, we document that the purified Hfq protein of the plant pathogen and natural genetic engineer Agrobacterium tumefaciens binds to the previously described sRNA AbcR1 and its target mRNA atu2422, which codes for the substrate binding protein of an ABC transporter taking up proline and γ-aminobutyric acid (GABA). Several other ABC transporter components were overproduced in an hfq mutant compared to their levels in the parental strain, suggesting that Hfq plays a major role in controlling the uptake systems and metabolic versatility of A. tumefaciens. The hfq mutant showed delayed growth, altered cell morphology, and reduced motility. Although the DNA-transferring type IV secretion system was produced, tumor formation by the mutant strain was attenuated, demonstrating an important contribution of Hfq to plant transformation by A. tumefaciens. PMID:22821981

Structure of a Type-1 Secretion System ABC Transporter.

PubMed

Morgan, Jacob L W; Acheson, Justin F; Zimmer, Jochen

2017-03-07

Type-1 secretion systems (T1SSs) represent a widespread mode of protein secretion across the cell envelope in Gram-negative bacteria. The T1SS is composed of an inner-membrane ABC transporter, a periplasmic membrane-fusion protein, and an outer-membrane porin. These three components assemble into a complex spanning both membranes and providing a conduit for the translocation of unfolded polypeptides. We show that ATP hydrolysis and assembly of the entire T1SS complex is necessary for protein secretion. Furthermore, we present a 3.15-Å crystal structure of AaPrtD, the ABC transporter found in the Aquifex aeolicus T1SS. The structure suggests a substrate entry window just above the transporter's nucleotide binding domains. In addition, highly kinked transmembrane helices, which frame a narrow channel not observed in canonical peptide transporters, are likely involved in substrate translocation. Overall, the AaPrtD structure supports a polypeptide transport mechanism distinct from alternating access. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification and characterization of cancer stem-like cells from primary carcinoma of the cervix uteri.

PubMed

Feng, Dingqing; Peng, Cheng; Li, Cairong; Zhou, Ying; Li, Min; Ling, Bin; Wei, Haiming; Tian, Zhigang

2009-11-01

Like many other solid tumors, cervical cancer contains a heterogeneous population of cancer cells. Several investigators have identified putative stem cells from solid tumors and cancer cell lines via the capacity to self renew and drive tumor formation. The aim of this study was to identify and characterize a cancer stem-like cell population from primary carcinoma of the cervix uteri. Cervical carcinoma from 19 patients staged I-II following International Federation of Gynecology and Obstetrics (FIGO) criteria were disaggregated and subjected to growth conditions selective for stem cells. Eight of nineteen tumor-derived cultures encompassed stem-like cells capable of self-renewal, extensive proliferation as clonal non-adherent spherical clusters. Cell markers of spheroid were identified as CD44+CK17+. Cell survival assays showed the sphere-forming cells were only 48% inhibited by doxorubicin whereas 78% inhibited by paclitaxel. Chemo-resistance may partly attribute to the exclusive expression of ABC transporter. To investigate the tumorigenicity of these stem-like cells, xenoengraftment of 10(5) dissociated spheroid cells allowed full recapitulation of the original tumor, whereas the same amount of tumor cells without non-adherent spheroid selection remained non-tumorigenic. Stemness properties of these spheroid cells were further established by reverse transcription-PCR and Western blotting, demonstrating the expression of embryonic and adult stemness-related genes (Oct-4, Piwil2, C-myc, Stat3 and Sox2). Based on these findings, we assert that cervical cancer contain a subpopulation of tumor initiating cells with stem-like properties, thus facilitating the approach to therapeutic strategies aimed at eradicating the tumorigenic subpopulation within cervical cancer.

Drug resistance is conferred on the model yeast Saccharomyces cerevisiae by expression of full-length melanoma-associated human ATP-binding cassette transporter ABCB5.

PubMed

Keniya, Mikhail V; Holmes, Ann R; Niimi, Masakazu; Lamping, Erwin; Gillet, Jean-Pierre; Gottesman, Michael M; Cannon, Richard D

2014-10-06

ABCB5, an ATP-binding cassette (ABC) transporter, is highly expressed in melanoma cells, and may contribute to the extreme resistance of melanomas to chemotherapy by efflux of anti-cancer drugs. Our goal was to determine whether we could functionally express human ABCB5 in the model yeast Saccharomyces cerevisiae, in order to demonstrate an efflux function for ABCB5 in the absence of background pump activity from other human transporters. Heterologous expression would also facilitate drug discovery for this important target. DNAs encoding ABCB5 sequences were cloned into the chromosomal PDR5 locus of a S. cerevisiae strain in which seven endogenous ABC transporters have been deleted. Protein expression in the yeast cells was monitored by immunodetection using both a specific anti-ABCB5 antibody and a cross-reactive anti-ABCB1 antibody. ABCB5 function in recombinant yeast cells was measured by determining whether the cells possessed increased resistance to known pump substrates, compared to the host yeast strain, in assays of yeast growth. Three ABCB5 constructs were made in yeast. One was derived from the ABCB5-β mRNA, which is highly expressed in human tissues but is a truncation of a canonical full-size ABC transporter. Two constructs contained full-length ABCB5 sequences: either a native sequence from cDNA or a synthetic sequence codon-harmonized for S. cerevisiae. Expression of all three constructs in yeast was confirmed by immunodetection. Expression of the codon-harmonized full-length ABCB5 DNA conferred increased resistance, relative to the host yeast strain, to the putative substrates rhodamine 123, daunorubicin, tetramethylrhodamine, FK506, or clorgyline. We conclude that full-length ABCB5 can be functionally expressed in S. cerevisiae and confers drug resistance.

A new fluorescent dye accumulation assay for parallel measurements of the ABCG2, ABCB1 and ABCC1 multidrug transporter functions.

PubMed

Szabó, Edit; Türk, Dóra; Telbisz, Ágnes; Kucsma, Nóra; Horváth, Tamás; Szakács, Gergely; Homolya, László; Sarkadi, Balázs; Várady, György

2018-01-01

ABC multidrug transporters are key players in cancer multidrug resistance and in general xenobiotic elimination, thus their functional assays provide important tools for research and diagnostic applications. In this study we have examined the potential interactions of three key human ABC multidrug transporters with PhenGreen diacetate (PGD), a cell permeable fluorescent metal ion indicator. The non-fluorescent, hydrophobic PGD rapidly enters the cells and, after cleavage by cellular esterases, in the absence of quenching metal ions, PhenGreen (PG) becomes highly fluorescent. We found that in cells expressing functional ABCG2, ABCB1, or ABCC1 transporters, cellular PG fluorescence is strongly reduced. This fluorescence signal in the presence of specific transporter inhibitors is increased to the fluorescence levels in the control cells. Thus the PG accumulation assay is a new, unique tool for the parallel determination of the function of the ABCG2, ABCB1, and ABCC1 multidrug transporters. Since PG has very low cellular toxicity, the PG accumulation assay also allows the selection, separation and culturing of selected cell populations expressing either of these transporters.

High-throughput combinatorial screening identifies drugs that cooperate with ibrutinib to kill activated B-cell–like diffuse large B-cell lymphoma cells

PubMed Central

Mathews Griner, Lesley A.; Guha, Rajarshi; Shinn, Paul; Young, Ryan M.; Keller, Jonathan M.; Liu, Dongbo; Goldlust, Ian S.; Yasgar, Adam; McKnight, Crystal; Boxer, Matthew B.; Duveau, Damien Y.; Jiang, Jian-Kang; Michael, Sam; Mierzwa, Tim; Huang, Wenwei; Walsh, Martin J.; Mott, Bryan T.; Patel, Paresma; Leister, William; Maloney, David J.; Leclair, Christopher A.; Rai, Ganesha; Jadhav, Ajit; Peyser, Brian D.; Austin, Christopher P.; Martin, Scott E.; Simeonov, Anton; Ferrer, Marc; Staudt, Louis M.; Thomas, Craig J.

2014-01-01

The clinical development of drug combinations is typically achieved through trial-and-error or via insight gained through a detailed molecular understanding of dysregulated signaling pathways in a specific cancer type. Unbiased small-molecule combination (matrix) screening represents a high-throughput means to explore hundreds and even thousands of drug–drug pairs for potential investigation and translation. Here, we describe a high-throughput screening platform capable of testing compounds in pairwise matrix blocks for the rapid and systematic identification of synergistic, additive, and antagonistic drug combinations. We use this platform to define potential therapeutic combinations for the activated B-cell–like subtype (ABC) of diffuse large B-cell lymphoma (DLBCL). We identify drugs with synergy, additivity, and antagonism with the Bruton’s tyrosine kinase inhibitor ibrutinib, which targets the chronic active B-cell receptor signaling that characterizes ABC DLBCL. Ibrutinib interacted favorably with a wide range of compounds, including inhibitors of the PI3K-AKT-mammalian target of rapamycin signaling cascade, other B-cell receptor pathway inhibitors, Bcl-2 family inhibitors, and several components of chemotherapy that is the standard of care for DLBCL. PMID:24469833

Genome-Wide Identification, Characterization and Phylogenetic Analysis of ATP-Binding Cassette (ABC) Transporter Genes in Common Carp (Cyprinus carpio).

PubMed

Liu, Xiang; Li, Shangqi; Peng, Wenzhu; Feng, Shuaisheng; Feng, Jianxin; Mahboob, Shahid; Al-Ghanim, Khalid A; Xu, Peng

2016-01-01

The ATP-binding cassette (ABC) gene family is considered to be one of the largest gene families in all forms of prokaryotic and eukaryotic life. Although the ABC transporter genes have been annotated in some species, detailed information about the ABC superfamily and the evolutionary characterization of ABC genes in common carp (Cyprinus carpio) are still unclear. In this research, we identified 61 ABC transporter genes in the common carp genome. Phylogenetic analysis revealed that they could be classified into seven subfamilies, namely 11 ABCAs, six ABCBs, 19 ABCCs, eight ABCDs, two ABCEs, four ABCFs, and 11 ABCGs. Comparative analysis of the ABC genes in seven vertebrate species including common carp, showed that at least 10 common carp genes were retained from the third round of whole genome duplication, while 12 duplicated ABC genes may have come from the fourth round of whole genome duplication. Gene losses were also observed for 14 ABC genes. Expression profiles of the 61 ABC genes in six common carp tissues (brain, heart, spleen, kidney, intestine, and gill) revealed extensive functional divergence among the ABC genes. Different copies of some genes had tissue-specific expression patterns, which may indicate some gene function specialization. This study provides essential genomic resources for future studies in common carp.

Genome-Wide Identification, Characterization and Phylogenetic Analysis of ATP-Binding Cassette (ABC) Transporter Genes in Common Carp (Cyprinus carpio)

PubMed Central

Peng, Wenzhu; Feng, Shuaisheng; Feng, Jianxin; Mahboob, Shahid; Al-Ghanim, Khalid A.

2016-01-01

The ATP-binding cassette (ABC) gene family is considered to be one of the largest gene families in all forms of prokaryotic and eukaryotic life. Although the ABC transporter genes have been annotated in some species, detailed information about the ABC superfamily and the evolutionary characterization of ABC genes in common carp (Cyprinus carpio) are still unclear. In this research, we identified 61 ABC transporter genes in the common carp genome. Phylogenetic analysis revealed that they could be classified into seven subfamilies, namely 11 ABCAs, six ABCBs, 19 ABCCs, eight ABCDs, two ABCEs, four ABCFs, and 11 ABCGs. Comparative analysis of the ABC genes in seven vertebrate species including common carp, showed that at least 10 common carp genes were retained from the third round of whole genome duplication, while 12 duplicated ABC genes may have come from the fourth round of whole genome duplication. Gene losses were also observed for 14 ABC genes. Expression profiles of the 61 ABC genes in six common carp tissues (brain, heart, spleen, kidney, intestine, and gill) revealed extensive functional divergence among the ABC genes. Different copies of some genes had tissue-specific expression patterns, which may indicate some gene function specialization. This study provides essential genomic resources for future studies in common carp. PMID:27058731

Three dimensional magnetohydrodynamic simulation of linearly polarised Alfven wave dynamics in Arnold-Beltrami-Childress magnetic field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsiklauri, D.

Previous studies (e.g., Malara et al., Astrophys. J. 533, 523 (2000)) considered small-amplitude Alfven wave (AW) packets in Arnold-Beltrami-Childress (ABC) magnetic field using WKB approximation. They draw a distinction between 2D AW dissipation via phase mixing and 3D AW dissipation via exponentially divergent magnetic field lines. In the former case, AW dissipation time scales as S{sup 1∕3} and in the latter as log(S), where S is the Lundquist number. In this work, linearly polarised Alfven wave dynamics in ABC magnetic field via direct 3D magnetohydrodynamic (MHD) numerical simulation is studied for the first time. A Gaussian AW pulse with length-scalemore » much shorter than ABC domain length and a harmonic AW with wavelength equal to ABC domain length are studied for four different resistivities. While it is found that AWs dissipate quickly in the ABC field, contrary to an expectation, it is found the AW perturbation energy increases in time. In the case of the harmonic AW, the perturbation energy growth is transient in time, attaining peaks in both velocity and magnetic perturbation energies within timescales much smaller than the resistive time. In the case of the Gaussian AW pulse, the velocity perturbation energy growth is still transient in time, attaining a peak within few resistive times, while magnetic perturbation energy continues to grow. It is also shown that the total magnetic energy decreases in time and this is governed by the resistive evolution of the background ABC magnetic field rather than AW damping. On contrary, when the background magnetic field is uniform, the total magnetic energy decrease is prescribed by AW damping, because there is no resistive evolution of the background. By considering runs with different amplitudes and by analysing the perturbation spectra, possible dynamo action by AW perturbation-induced peristaltic flow and inverse cascade of magnetic energy have been excluded. Therefore, the perturbation energy growth is attributed to a new instability. The growth rate appears to be dependent on the value of the resistivity and the spatial scale of the AW disturbance. Thus, when going beyond WKB approximation, AW damping, described by full MHD equations, does not guarantee decrease of perturbation energy. This has implications for the MHD wave plasma heating in exponentially divergent magnetic fields.« less

Aneurysmal Bone Cyst: An Analysis of 38 Cases and Report of Four Unusual Surface Ones

PubMed Central

Shooshtarizadeh, Tina; Movahedinia, Sajjadeh; Mostafavi, Hassan; Jamshidi, Khodamorad; Sami, Sam Hajialiloo

2016-01-01

Aneurysmal bone cyst (ABC) is a benign expansile bone tumor, most commonly involving the medulla of long bones. ABC rarely arises within the cortex or in the subperiosteal region, radiographically mimicking other conditions, in particular surface osteosarcomathat is low-grade in nature and may go secondary ABC changes, and telangiectatic osteosarcoma. Both of these are sometimes mistaken microscopically for primary ABC. We review the characteristics of ABC cases in our center and report four unusualsurface ABCs arising in the subperiosteal or cortical region of long bones, identified among 38 histologically proven ABCs during a four-year period in our center. The surface ABCs occurred at an older agewith a predilection for diaphysis of femur, tibia, and humerus. PMID:27200397

Independent activity of the homologous small regulatory RNAs AbcR1 and AbcR2 in the legume symbiont Sinorhizobium meliloti.

PubMed

Torres-Quesada, Omar; Millán, Vicenta; Nisa-Martínez, Rafael; Bardou, Florian; Crespi, Martín; Toro, Nicolás; Jiménez-Zurdo, José I

2013-01-01

The legume symbiont Sinorhizobium meliloti expresses a plethora of small noncoding RNAs (sRNAs) whose function is mostly unknown. Here, we have functionally characterized two tandemly encoded S. meliloti Rm1021 sRNAs that are similar in sequence and structure. Homologous sRNAs (designated AbcR1 and AbcR2) have been shown to regulate several ABC transporters in the related α-proteobacteria Agrobacterium tumefaciens and Brucella abortus. In Rm1021, AbcR1 and AbcR2 exhibit divergent unlinked regulation and are stabilized by the RNA chaperone Hfq. AbcR1 is transcribed in actively dividing bacteria, either in culture, rhizosphere or within the invasion zone of mature alfalfa nodules. Conversely, AbcR2 expression is induced upon entry into stationary phase and under abiotic stress. Only deletion of AbcR1 resulted into a discrete growth delay in rich medium, but both are dispensable for symbiosis. Periplasmic proteome profiling revealed down-regulation of the branched-chain amino acid binding protein LivK by AbcR1, but not by AbcR2. A double-plasmid reporter assay confirmed the predicted specific targeting of the 5'-untranslated region of the livK mRNA by AbcR1 in vivo. Our findings provide evidences of independent regulatory functions of these sRNAs, probably to fine-tune nutrient uptake in free-living and undifferentiated symbiotic rhizobia.

Independent Activity of the Homologous Small Regulatory RNAs AbcR1 and AbcR2 in the Legume Symbiont Sinorhizobium meliloti

PubMed Central

Torres-Quesada, Omar; Millán, Vicenta; Nisa-Martínez, Rafael; Bardou, Florian; Crespi, Martín; Toro, Nicolás; Jiménez-Zurdo, José I.

2013-01-01

The legume symbiont Sinorhizobium meliloti expresses a plethora of small noncoding RNAs (sRNAs) whose function is mostly unknown. Here, we have functionally characterized two tandemly encoded S. meliloti Rm1021 sRNAs that are similar in sequence and structure. Homologous sRNAs (designated AbcR1 and AbcR2) have been shown to regulate several ABC transporters in the related α-proteobacteria Agrobacterium tumefaciens and Brucella abortus. In Rm1021, AbcR1 and AbcR2 exhibit divergent unlinked regulation and are stabilized by the RNA chaperone Hfq. AbcR1 is transcribed in actively dividing bacteria, either in culture, rhizosphere or within the invasion zone of mature alfalfa nodules. Conversely, AbcR2 expression is induced upon entry into stationary phase and under abiotic stress. Only deletion of AbcR1 resulted into a discrete growth delay in rich medium, but both are dispensable for symbiosis. Periplasmic proteome profiling revealed down-regulation of the branched-chain amino acid binding protein LivK by AbcR1, but not by AbcR2. A double-plasmid reporter assay confirmed the predicted specific targeting of the 5′-untranslated region of the livK mRNA by AbcR1 in vivo. Our findings provide evidences of independent regulatory functions of these sRNAs, probably to fine-tune nutrient uptake in free-living and undifferentiated symbiotic rhizobia. PMID:23869210

Statistical Hypothesis Testing in Intraspecific Phylogeography: NCPA versus ABC

PubMed Central

Templeton, Alan R.

2009-01-01

Nested clade phylogeographic analysis (NCPA) and approximate Bayesian computation (ABC) have been used to test phylogeographic hypotheses. Multilocus NCPA tests null hypotheses, whereas ABC discriminates among a finite set of alternatives. The interpretive criteria of NCPA are explicit and allow complex models to be built from simple components. The interpretive criteria of ABC are ad hoc and require the specification of a complete phylogeographic model. The conclusions from ABC are often influenced by implicit assumptions arising from the many parameters needed to specify a complex model. These complex models confound many assumptions so that biological interpretations are difficult. Sampling error is accounted for in NCPA, but ABC ignores important sources of sampling error that creates pseudo-statistical power. NCPA generates the full sampling distribution of its statistics, but ABC only yields local probabilities, which in turn make it impossible to distinguish between a good fitting model, a non-informative model, and an over-determined model. Both NCPA and ABC use approximations, but convergences of the approximations used in NCPA are well defined whereas those in ABC are not. NCPA can analyze a large number of locations, but ABC cannot. Finally, the dimensionality of tested hypothesis is known in NCPA, but not for ABC. As a consequence, the “probabilities” generated by ABC are not true probabilities and are statistically non-interpretable. Accordingly, ABC should not be used for hypothesis testing, but simulation approaches are valuable when used in conjunction with NCPA or other methods that do not rely on highly parameterized models. PMID:19192182

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, J; Hill, G; Spiegel, J

Purpose: To investigate the clinical and dosimetric benefits of automatic gating of left breast mixed with breath-hold technique. Methods: Two Active Breathing Control systems, ABC2.0 and ABC3.0, were used during simulation and treatment delivery. The two systems are different such that ABC2.0 is a breath-hold system without beam control capability, while ABC3.0 has capability in both breath-hold and beam gating. At simulation, each patient was scanned twice: one with free breathing (FB) and one with breath hold through ABC. Treatment plan was generated on the CT with ABC. The same plan was also recalculated on the CT with FB. Thesemore » two plans were compared to assess plan quality. For treatments with ABC2.0, beams with MU > 55 were manually split into multiple subfields. All subfields were identical and shared the total MU. For treatment with ABC3.0, beam splitting was unnecessary. Instead, treatment was delivered in gating mode mixed with breath-hold technique. Treatment delivery efficiency using the two systems was compared. Results: The prescribed dose was 50.4Gy at 1.8Gy/fraction. The maximum heart dose averaged over 10 patients was 46.0±2.5Gy and 24.5±12.2Gy for treatments with FB and with ABC respectively. The corresponding heart V10 was 13.2±3.6% and 1.0±1.6% respectively. The averaged MUs were 99.8±7.5 for LMT, 99.2±9.4 for LLT. For treatment with ABC2.0, normally the original beam was split into 2 subfields. The averaged total time to delivery all beams was 4.3±0.4min for treatments with ABC2.0 and 3.3±0.6min for treatments with ABC3.0 in gating mode. Conclusion: Treatment with ABC tremendously reduced heart dose. Compared to treatments with ABC2.0, gating with ABC3.0 reduced the total treatment time by 23%. Use of ABC3.0 improved the delivery efficiency, and eliminated the possibility of mistreatments. The latter may happen with ABC2.0 where beam is not terminated when breath signal falls outside of the treatment window.« less

Emission of volatile organic compounds from petunia flowers is facilitated by an ABC transporter.

PubMed

Adebesin, Funmilayo; Widhalm, Joshua R; Boachon, Benoît; Lefèvre, François; Pierman, Baptiste; Lynch, Joseph H; Alam, Iftekhar; Junqueira, Bruna; Benke, Ryan; Ray, Shaunak; Porter, Justin A; Yanagisawa, Makoto; Wetzstein, Hazel Y; Morgan, John A; Boutry, Marc; Schuurink, Robert C; Dudareva, Natalia

2017-06-30

Plants synthesize a diversity of volatile molecules that are important for reproduction and defense, serve as practical products for humans, and influence atmospheric chemistry and climate. Despite progress in deciphering plant volatile biosynthesis, their release from the cell has been poorly understood. The default assumption has been that volatiles passively diffuse out of cells. By characterization of a Petunia hybrida adenosine triphosphate-binding cassette (ABC) transporter, PhABCG1, we demonstrate that passage of volatiles across the plasma membrane relies on active transport. PhABCG1 down-regulation by RNA interference results in decreased emission of volatiles, which accumulate to toxic levels in the plasma membrane. This study provides direct proof of a biologically mediated mechanism of volatile emission. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Dolutegravir plus abacavir-lamivudine for the treatment of HIV-1 infection.

PubMed

Walmsley, Sharon L; Antela, Antonio; Clumeck, Nathan; Duiculescu, Dan; Eberhard, Andrea; Gutiérrez, Felix; Hocqueloux, Laurent; Maggiolo, Franco; Sandkovsky, Uriel; Granier, Catherine; Pappa, Keith; Wynne, Brian; Min, Sherene; Nichols, Garrett

2013-11-07

Dolutegravir (S/GSK1349572), a once-daily, unboosted integrase inhibitor, was recently approved in the United States for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in combination with other antiretroviral agents. Dolutegravir, in combination with abacavir-lamivudine, may provide a simplified regimen. We conducted a randomized, double-blind, phase 3 study involving adult participants who had not received previous therapy for HIV-1 infection and who had an HIV-1 RNA level of 1000 copies per milliliter or more. Participants were randomly assigned to dolutegravir at a dose of 50 mg plus abacavir-lamivudine once daily (DTG-ABC-3TC group) or combination therapy with efavirenz-tenofovir disoproxil fumarate (DF)-emtricitabine once daily (EFV-TDF-FTC group). The primary end point was the proportion of participants with an HIV-1 RNA level of less than 50 copies per milliliter at week 48. Secondary end points included the time to viral suppression, the change from baseline in CD4+ T-cell count, safety, and viral resistance. A total of 833 participants received at least one dose of study drug. At week 48, the proportion of participants with an HIV-1 RNA level of less than 50 copies per milliliter was significantly higher in the DTG-ABC-3TC group than in the EFV-TDF-FTC group (88% vs. 81%, P=0.003), thus meeting the criterion for superiority. The DTG-ABC-3TC group had a shorter median time to viral suppression than did the EFV-TDF-FTC group (28 vs. 84 days, P<0.001), as well as greater increases in CD4+ T-cell count (267 vs. 208 per cubic millimeter, P<0.001). The proportion of participants who discontinued therapy owing to adverse events was lower in the DTG-ABC-3TC group than in the EFV-TDF-FTC group (2% vs. 10%); rash and neuropsychiatric events (including abnormal dreams, anxiety, dizziness, and somnolence) were significantly more common in the EFV-TDF-FTC group, whereas insomnia was reported more frequently in the DTG-ABC-3TC group. No participants in the DTG-ABC-3TC group had detectable antiviral resistance; one tenofovir DF-associated mutation and four efavirenz-associated mutations were detected in participants with virologic failure in the EFV-TDF-FTC group. Dolutegravir plus abacavir-lamivudine had a better safety profile and was more effective through 48 weeks than the regimen with efavirenz-tenofovir DF-emtricitabine. (Funded by ViiV Healthcare; SINGLE ClinicalTrials.gov number, NCT01263015 .).

¹⁸FDG a PET tumor diagnostic tracer is not a substrate of the ABC transporter P-glycoprotein.

PubMed

Krasznai, Zoárd T; Trencsényi, György; Krasznai, Zoltán; Mikecz, Pál; Nizsalóczki, Enikő; Szalóki, Gábor; Szabó, Judit P; Balkay, László; Márián, Teréz; Goda, Katalin

2014-11-20

2-[(18)F]fluoro-2-deoxy-d-glucose ((18)FDG) is a tumor diagnostic radiotracer of great importance in both diagnosing primary and metastatic tumors and in monitoring the efficacy of the treatment. P-glycoprotein (Pgp) is an active transporter that is often expressed in various malignancies either intrinsically or appears later upon disease progression or in response to chemotherapy. Several authors reported that the accumulation of (18)FDG in P-glycoprotein (Pgp) expressing cancer cells (Pgp(+)) and tumors is different from the accumulation of the tracer in Pgp nonexpressing (Pgp(-)) ones, therefore we investigated whether (18)FDG is a substrate or modulator of Pgp pump. Rhodamine 123 (R123) accumulation experiments and ATPase assay were used to detect whether (18)FDG is substrate for Pgp. The accumulation and efflux kinetics of (18)FDG were examined in two different human gynecologic (A2780/A2780AD and KB-3-1/KB-V1) and a mouse fibroblast (3T3 and 3T3MDR1) Pgp(+) and Pgp(-) cancer cell line pairs both in cell suspension and monolayer cultures. We found that (18)FDG and its derivatives did not affect either the R123 accumulation in Pgp(+) cells or the basal and the substrate stimulated ATPase activity of Pgp supporting that they are not substrates or modulators of the pump. Measuring the accumulation and efflux kinetics of (18)FDG in different Pgp(+) and Pgp(-) cell line pairs, we have found that the Pgp(+) cells exhibited significantly higher (p⩽0.01) (18)FDG accumulation and slightly faster (18)FDG efflux kinetics compared to their Pgp(-) counterparts. The above data support the idea that expression of Pgp may increase the energy demand of cells resulting in higher (18)FDG accumulation and faster efflux. We concluded that (18)FDG and its metabolites are not substrates of Pgp. Copyright © 2014 Elsevier B.V. All rights reserved.

An Arabidopsis lipid flippase is required for timely recruitment of defenses to the host-pathogen interface at the plant cell surface

USDA-ARS?s Scientific Manuscript database

Deposition of cell wall-reinforcing papillae is an integral component of the plant immune response. The Arabidopsis PENETRATION 3 (PEN3) ATP binding cassette (ABC) transporter plays a role in defense against numerous pathogens and is recruited to sites of pathogen detection where it accumulates with...

Catalytic and transport cycles of ABC exporters.

PubMed

Al-Shawi, Marwan K

2011-09-07

ABC (ATP-binding cassette) transporters are arguably the most important family of ATP-driven transporters in biology. Despite considerable effort and advances in determining the structures and physiology of these transporters, their fundamental molecular mechanisms remain elusive and highly controversial. How does ATP hydrolysis by ABC transporters drive their transport function? Part of the problem in answering this question appears to be a perceived need to formulate a universal mechanism. Although it has been generally hoped and assumed that the whole superfamily of ABC transporters would exhibit similar conserved mechanisms, this is proving not to be the case. Structural considerations alone suggest that there are three overall types of coupling mechanisms related to ABC exporters, small ABC importers and large ABC importers. Biochemical and biophysical characterization leads us to the conclusion that, even within these three classes, the catalytic and transport mechanisms are not fully conserved, but continue to evolve. ABC transporters also exhibit unusual characteristics not observed in other primary transporters, such as uncoupled basal ATPase activity, that severely complicate mechanistic studies by established methods. In this chapter, I review these issues as related to ABC exporters in particular. A consensus view has emerged that ABC exporters follow alternating-access switch transport mechanisms. However, some biochemical data suggest that alternating catalytic site transport mechanisms are more appropriate for fully symmetrical ABC exporters. Heterodimeric and asymmetrical ABC exporters appear to conform to simple alternating-access-type mechanisms.

CXCL4/Platelet Factor 4 is an agonist of CCR1 and drives human monocyte migration.

PubMed

Fox, James M; Kausar, Fahima; Day, Amy; Osborne, Michael; Hussain, Khansa; Mueller, Anja; Lin, Jessica; Tsuchiya, Tomoko; Kanegasaki, Shiro; Pease, James E

2018-06-21

Activated platelets release micromolar concentrations of the chemokine CXCL4/Platelet Factor-4. Deposition of CXCL4 onto the vascular endothelium is involved in atherosclerosis, facilitating monocyte arrest and recruitment by an as yet, unidentified receptor. Here, we demonstrate that CXCL4 drives chemotaxis of the monocytic cell line THP-1. Migration and intracellular calcium responses induced by CXCL4 were pertussis toxin-sensitive, implicating a GPCR in signal transduction. Cell treatment with chondroitinase ABC ablated migration, suggesting that cis presentation of CXCL4 by cell surface glycosaminoglycans to a GPCR is required. Although CXCR3 has been previously described as a CXCL4 receptor, THP-1 cells were unresponsive to CXCR3 ligands and CXCL4-induced migration was insensitive to a CXCR3 antagonist, suggesting that an alternative receptor is involved. Interrogating CC-class chemokine receptor transfectants, we unexpectedly found that CXCL4 could induce the migration of CCR1-expressing cells and also induce CCR1 endocytosis. Extending our findings to primary human monocytes, we observed that CXCL4 induced CCR1 endocytosis and could induce monocyte chemotaxis in a CCR1 antagonist-sensitive manner. Collectively, our data identify CCR1 as a previously elusive monocyte CXCL4 receptor and suggest that CCR1 may play a role in inflammation where the release of CXCL4 is implicated.

4th International Consensus Conference on Advanced Breast Cancer (ABC4), Lisbon, November 4, 2017 : ABC4 Consensus: Assessment by a Panel of German Experts.

PubMed

Untch, Michael; Würstlein, Rachel; Marschner, Norbert; Lüftner, Diana; Augustin, Doris; Briest, Susanne; Ettl, Johannes; Haidinger, Renate; Müller, Lothar; Müller, Volkmar; Ruckhäberle, Eugen; Harbeck, Nadia; Thomssen, Christoph

2018-05-01

The fourth international advanced breast cancer consensus conference (ABC4) on the diagnosis and treatment of advanced breast cancer (ABC) headed by Professor Fatima Cardoso was once again held in Lisbon on November 2 - 4, 2017. To simplify matters, the abbreviation ABC will be used hereinafter in the text. In clinical practice, the abbreviation corresponds to metastatic breast cancer or locally far-advanced disease. This year the focus was on new developments in the treatment of ABC. Topics discussed included the importance of CDK4/6 inhibition in hormone receptor (HR)-positive ABC, the use of dual antibody blockade to treat HER2-positive ABC, PARP inhibition in triple-negative ABC and the potential therapeutic outcomes. Another major area discussed at the conference was BRCA-associated breast cancer, the treatment of cerebral metastasis, and individualized treatment decisions based on molecular testing (so-called precision medicine). As in previous years, close cooperation with representatives from patient organizations from around the world is an important aspect of the ABC conference. This cooperation was reinforced and expanded at the ABC4 conference. A global alliance was founded at the conclusion of the consensus conference, which aims to promote and coordinate the measures considered necessary by patient advocates worldwide. Because the panel of experts was composed of specialists from all over the world, it was inevitable that the ABC consensus also reflected country-specific features. As in previous years, a team of German breast cancer specialists who closely followed the consensus voting of the ABC panelists in Lisbon and intensively discussed the votes has therefore commented on the consensus in the context of the current German guidelines on the diagnosis and treatment of breast cancer 1 ,  2 used in clinical practice in Germany. The ABC consensus is based on the votes of the ABC panelists in Lisbon.

Sustained delivery of thermostabilized chABC enhances axonal sprouting and functional recovery after spinal cord injury.

PubMed

Lee, Hyunjung; McKeon, Robert J; Bellamkonda, Ravi V

2010-02-23

Chondroitin sulfate proteoglycans (CSPGs) are a major class of axon growth inhibitors that are up-regulated after spinal cord injury (SCI) and contribute to regenerative failure. Chondroitinase ABC (chABC) digests glycosaminoglycan chains on CSPGs and can thereby overcome CSPG-mediated inhibition. But chABC loses its enzymatic activity rapidly at 37 degrees C, necessitating the use of repeated injections or local infusions for a period of days to weeks. These infusion systems are invasive, infection-prone, and clinically problematic. To overcome this limitation, we have thermostabilized chABC and developed a system for its sustained local delivery in vivo, obviating the need for chronically implanted catheters and pumps. Thermostabilized chABC remained active at 37 degrees C in vitro for up to 4 weeks. CSPG levels remained low in vivo up to 6 weeks post-SCI when thermostabilized chABC was delivered by a hydrogel-microtube scaffold system. Axonal growth and functional recovery following the sustained local release of thermostabilized chABC versus a single treatment of unstabilized chABC demonstrated significant differences in CSPG digestion. Animals treated with thermostabilized chABC in combination with sustained neurotrophin-3 delivery showed significant improvement in locomotor function and enhanced growth of cholera toxin B subunit-positive sensory axons and sprouting of serotonergic fibers. Therefore, improving chABC thermostability facilitates minimally invasive, sustained, local delivery of chABC that is potentially effective in overcoming CSPG-mediated regenerative failure. Combination therapy with thermostabilized chABC with neurotrophic factors enhances axonal regrowth, sprouting, and functional recovery after SCI.

Francisella tularensis Live Vaccine Strain deficient in capB and overexpressing the fusion protein of IglA, IglB, and IglC from the bfr promoter induces improved protection against F. tularensis respiratory challenge.

PubMed

Jia, Qingmei; Bowen, Richard; Lee, Bai-Yu; Dillon, Barbara Jane; Masleša-Galić, Saša; Horwitz, Marcus A

2016-09-22

A safer and more effective vaccine than the unlicensed Francisella tularensis Live Vaccine Strain (LVS) is needed to protect against the biowarfare agent F. tularensis. Previously, we developed an LVS ΔcapB mutant that is significantly safer than LVS and provides potent protective immunity against F. tularensis respiratory challenge when administered intranasally but limited protection when administered intradermally unless as part of a prime-boost vaccination strategy. To improve the immunogenicity and efficacy of LVS ΔcapB, we developed recombinant LVS ΔcapB (rLVS ΔcapB) strains overexpressing various F. tularensis Francisella Pathogenicity Island (FPI) proteins - IglA, IglB and IglC, and a fusion protein (IglABC) comprising immunodominant epitopes of IglA, IglB, and IglC downstream of different Francisella promoters, including the bacterioferritin (bfr) promoter. We show that rLVS ΔcapB/bfr-iglA, iglB, iglC, and iglABC express more IglA, IglB, IglC or IglABC than parental LVS ΔcapB in broth and in human macrophages, and stably express FPI proteins in macrophages and mice absent antibiotic selection. In response to IglC and heat-inactivated LVS, spleen cells from mice immunized intradermally with rLVS ΔcapB/bfr-iglC or bfr-iglABC secrete greater amounts of interferon-gamma and/or interleukin-17 than those from mice immunized with LVS ΔcapB, comparable to those from LVS-immunized mice. Mice immunized with rLVS ΔcapB/bfr-iglA, iglB, iglC or iglABC produce serum antibodies at levels similar to LVS-immunized mice. Mice immunized intradermally with rLVS ΔcapB/bfr-iglABC and challenged intranasally with virulent F. tularensis Schu S4 survive longer than sham- and LVS ΔcapB-immunized mice. Mice immunized intranasally with rLVS ΔcapB/bfr-iglABC - but not with LVS - just before or after respiratory challenge with F. tularensis Schu S4 are partially protected; protection is correlated with induction of a strong innate immune response. Thus, rLVS ΔcapB/bfr-iglABC shows improved immunogenicity and protective efficacy compared with parental LVS ΔcapB and, in contrast to LVS, has partial efficacy as immediate pre- and post-exposure prophylaxis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Induction of the c-myc protooncogene following antigen binding to hapten-specific B cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Snow, E.C.; Fetherston, J.; Zimmer, S.

1986-03-01

Considerable controversy has centered on the role that the surface immunoglobulin (sIg) receptor for antigen plays during the induction of B cell activation. Stimulation by anti-Ig reagents has been shown to activate G/sub 0/ B cells to enter the cell cycle. The binding of thymus-dependent antigens to hapten-specific B cell populations apparently does not result in the movement of the antigen-binding cells (ABC) into the G/sub 1/ stage of the cell cycle. However, the authors have recently demonstrated that antigen binding to such hapten-specific B cells does result in the initiation of the membrane phosphatidylinositol cycle. In the present experiments,more » hapten-specific B cells (80-90% ABC, 99% in G/sub 0/) were incubated with either the correct hapten-carrier conjugate, with the carrier protein, or only media for 2 hours at 37/sup 0/C. At that time, total cellular RNA was isolated and subsequently analyzed by either dot blots or Northern gel techniques. The blots were probed with a (/sup 32/P)-c-myc SstI-Xhol fragment. The results indicate that hapten carrier stimulation of the hapten-specific B cells induces enhanced transcription of the c-myc gene. These observations lend further support to the premise that antigen binding to the sIg receptor results in the transduction to the cell of important signals and implicates the active participation of sIg during the process of antigen-mediated B cell activation.« less

Hijacking membrane transporters for arsenic phytoextraction

PubMed Central

LeBlanc, Melissa S.; McKinney, Elizabeth C.; Meagher, Richard B.; Smith, Aaron P.

2012-01-01

Arsenic is a toxic metalloid and recognized carcinogen. Arsenate and arsenite are the most common arsenic species available for uptake by plants. As an inorganic phosphate (Pi) analog, arsenate is acquired by plant roots through endogenous Pi transport systems. Inside the cell, arsenate is reduced to the thiol-reactive form arsenite. Glutathione (GSH)-conjugates of arsenite may be extruded from the cell or sequestered in vacuoles by members of the ATP-binding cassette (ABC) family of transporters. In the present study we sought to enhance both plant arsenic uptake through Pi transporter overexpression, and plant arsenic tolerance through ABC transporter overexpression. We demonstrate that Arabidopsis thaliana plants overexpressing the high-affinity Pi transporter family members, AtPht1;1 or AtPht1;7, are hypersensitive to arsenate due to increased arsenate uptake. These plants do not exhibit increased sensitivity to arsenite. Co-overexpression of the yeast ABC transporter YCF1 in combination with AtPht1;1 or AtPht1;7 suppresses the arsenate-sensitive phenotype while further enhancing arsenic uptake. Taken together, our results support an arsenic transport mechanism in which arsenate uptake is increased through Pi transporter overexpression, and arsenic tolerance is enhanced through YCF1-mediated vacuolar sequestration. This work substantiates the viability of coupling enhanced uptake and vacuolar sequestration as a means for developing a prototypical engineered arsenic hyperaccumulator. PMID:23108027

MDR1 and BCRP Transporter-Mediated Drug-Drug Interaction between Rilpivirine and Abacavir and Effect on Intestinal Absorption.

PubMed

Reznicek, Josef; Ceckova, Martina; Ptackova, Zuzana; Martinec, Ondrej; Tupova, Lenka; Cerveny, Lukas; Staud, Frantisek

2017-09-01

Rilpivirine (TMC278) is a highly potent nonnucleoside reverse transcriptase inhibitor (NNRTI) representing an effective component of combination antiretroviral therapy (cART) in the treatment of HIV-positive patients. Many antiretroviral drugs commonly used in cART are substrates of ATP-binding cassette (ABC) and/or solute carrier (SLC) drug transporters and, therefore, are prone to pharmacokinetic drug-drug interactions (DDIs). The aim of our study was to evaluate rilpivirine interactions with abacavir and lamivudine on selected ABC and SLC transporters in vitro and assess its importance for pharmacokinetics in vivo Using accumulation assays in MDCK cells overexpressing selected ABC or SLC drug transporters, we revealed rilpivirine as a potent inhibitor of MDR1 and BCRP, but not MRP2, OCT1, OCT2, or MATE1. Subsequent transport experiments across monolayers of MDCKII-MDR1, MDCKII-BCRP, and Caco-2 cells demonstrated that rilpivirine inhibits MDR1- and BCRP-mediated efflux of abacavir and increases its transmembrane transport. In vivo experiments in male Wistar rats confirmed inhibition of MDR1/BCRP in the small intestine, leading to a significant increase in oral bioavailability of abacavir. In conclusion, rilpivirine inhibits MDR1 and BCRP transporters and may affect pharmacokinetic behavior of concomitantly administered substrates of these transporters, such as abacavir. Copyright © 2017 American Society for Microbiology.

Human breast adipose tissue: characterization of factors that change during tumor progression in human breast cancer.

PubMed

Fletcher, Sabrina Johanna; Sacca, Paula Alejandra; Pistone-Creydt, Mercedes; Coló, Federico Andrés; Serra, María Florencia; Santino, Flavia Eliana; Sasso, Corina Verónica; Lopez-Fontana, Constanza Matilde; Carón, Rubén Walter; Calvo, Juan Carlos; Pistone-Creydt, Virginia

2017-02-07

Adipose microenvironment is involved in signaling pathways that influence breast cancer. We aim to characterize factors that are modified: 1) in tumor and non tumor human breast epithelial cell lines when incubated with conditioned media (CMs) from human breast cancer adipose tissue explants (hATT) or normal breast adipose tissue explants (hATN); 2) in hATN-CMs vs hATT-CMs; 3) in the tumor associated adipocytes vs. non tumor associated adipocytes. We used hATN or hATT- CMs on tumor and non-tumor breast cancer cell lines. We evaluated changes in versican, CD44, ADAMTS1 and Adipo R1 expression on cell lines or in the different CMs. In addition we evaluated changes in the morphology and expression of these factors in slices of the different adipose tissues. The statistical significance between different experimental conditions was evaluated by one-way ANOVA. Tukey's post-hoc tests were performed within each individual treatment. hATT-CMs increase versican, CD44, ADAMTS1 and Adipo R1 expression in breast cancer epithelial cells. Furthermore, hATT-CMs present higher levels of versican expression compared to hATN-CMs. In addition, we observed a loss of effect in cellular migration when we pre-incubated hATT-CMs with chondroitinase ABC, which cleaves GAGs chains bound to the versican core protein, thus losing the ability to bind to CD44. Adipocytes associated with the invasive front are reduced in size compared to adipocytes that are farther away. Also, hATT adipocytes express significantly higher amounts of versican, CD44 and Adipo R1, and significantly lower amounts of adiponectin and perilipin, unlike hATN adipocytes. We conclude that hATT secrete a different set of proteins compared to hATN. Furthermore, versican, a proteoglycan that is overexpressed in hATT-CMs compared to hATN-CMs, might be involved in the tumorogenic behavior observed in both cell lines employed. In addition, we may conclude that adipocytes from the tumor microenvironment show a less differentiated state than adipocytes from normal microenvironment. This would indicate a loss of normal functions in mature adipocytes (such as energy storage), in support of others that might favor tumor growth.

Stereotactic body radiation therapy for early-stage primary lung cancer, is an active breath coordinator necessary? An audit from a tertiary cancer care center.

PubMed

Madhavan, R; Renilmon, P S; Nair, H M; Lal, A; Nair, S S; Unnikrishnan, U G; Makuny, D

2017-01-01

The hypofractionated stereotactic body radiation therapy (SBRT) has emerged as a safe and effective treatment modality for early-stage nonsmall cell lung carcinoma. An audit SBRT in primary lung cancer treated in our center with and without an active breath coordinator (ABC) was undertaken to evaluate its impact on target volumes and clinical outcomes. This was an observational study. Nine patients with lung carcinoma were treated from January 2014 to August 2016. Five patients were simulated using ABC and four patients with free breathing. Volumetric modulated arc therapy plans were generated using Monaco treatment planning software. Three patients were treated with a dose of 54 Gy in three fractions and six patients with a dose of 48 Gy in four fractions. The statistical analysis was performed using Kaplan-Meier survival. The mean planning target volumes (PTV) in ABC and free breathing groups were 42.19cc and 60.17cc, respectively. The mean volume of lung receiving 20, 10, and 5 Gy (V20, V10and V5) in ABC group were 5.37cc, 10.49cc, and 18.45cc whereas in free breathing 6.63cc, 12.74cc, and 20.64cc, respectively. At a median follow-up of 18 months, there were three local recurrences. No significant toxicity occurred in our series. Our initial results show that SBRT is well tolerated with good local control. Although the PTV volume and irradiated normal lung volume was higher in this group compared to ABC group, this did not translate to any added clinical toxicity.

Use of a Short-Form Balance Confidence Scale to Predict Future Recurrent Falls in People With Parkinson Disease.

PubMed

Cole, Michael H; Rippey, Jodi; Naughton, Geraldine A; Silburn, Peter A

2016-01-01

To assess whether the 16-item Activities-specific Balance Confidence scale (ABC-16) and short-form 6-item Activities-specific Balance Confidence scale (ABC-6) could predict future recurrent falls in people with Parkinson disease (PD) and to validate the robustness of their predictive capacities. Twelve-month prospective cohort study. General community. People with idiopathic PD (N=79). Clinical tests were conducted to assess symptom severity, balance confidence, and medical history. Over the subsequent 12 months, participants recorded any falls on daily fall calendars, which they returned monthly by reply paid post. Logistic regression and receiver operating characteristic analyses estimated the sensitivities and specificities of the ABC-16 and ABC-6 for predicting future recurrent falls in this cohort, and "leave-one-out" validation was used to assess their robustness. Of the 79 patients who completed follow-up, 28 (35.4%) fell more than once during the 12-month period. Both the ABC-16 and ABC-6 were significant predictors of future recurrent falls, and moderate sensitivities (ABC-16: 75.0%; ABC-6: 71.4%) and specificities (ABC-16: 76.5%; ABC-6: 74.5%) were reported for each tool for a cutoff score of 77.5 and 65.8, respectively. The results have significant implications and demonstrate that the ABC-16 and ABC-6 independently identify patients with PD at risk of future recurrent falls. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

DS-8201a, a new HER2-targeting antibody-drug conjugate incorporating a novel DNA topoisomerase I inhibitor, overcomes HER2-positive gastric cancer T-DM1 resistance.

PubMed

Takegawa, Naoki; Nonagase, Yoshikane; Yonesaka, Kimio; Sakai, Kazuko; Maenishi, Osamu; Ogitani, Yusuke; Tamura, Takao; Nishio, Kazuto; Nakagawa, Kazuhiko; Tsurutani, Junji

2017-10-15

Anti-HER2 therapies are beneficial for patients with HER2-positive breast or gastric cancer. T-DM1 is a HER2-targeting antibody-drug conjugate (ADC) comprising the antibody trastuzumab, a linker, and the tubulin inhibitor DM1. Although effective in treating advanced breast cancer, all patients eventually develop T-DM1 resistance. DS-8201a is a new ADC incorporating an anti-HER2 antibody, a newly developed, enzymatically cleavable peptide linker, and a novel, potent, exatecan-derivative topoisomerase I inhibitor (DXd). DS-8201a has a drug-to-antibody-ratio (DAR) of 8, which is higher than that of T-DM1 (3.5). Owing to these unique characteristics and unlike T-DM1, DS-8201a is effective against cancers with low-HER2 expression. In the present work, T-DM1-resistant cells (N87-TDMR), established using the HER2-positive gastric cancer line NCI-N87 and continuous T-DM1 exposure, were shown to be susceptible to DS-8201a. The ATP-binding cassette (ABC) transporters ABCC2 and ABCG2 were upregulated in N87-TDMR cells, but HER2 overexpression was retained. Furthermore, inhibition of ABCC2 and ABCG2 by MK571 restored T-DM1 sensitivity. Therefore, resistance to T-DM1 is caused by efflux of its payload DM1, due to aberrant expression of ABC transporters. In contrast to DM1, DXd payload of DS-8201a inhibited the growth of N87-TDMR cells in vitro. This suggests that either DXd may be a poor substrate of ABCC2 and ABCG2 in comparison to DM1, or the high DAR of DS-8201a relative to T-DM1 compensates for increased efflux. Notably, N87-TDMR xenograft tumor growth was prevented by DS-8201a. In conclusion, the efficacy of DS-8201a as a treatment for patients with T-DM1-resistant breast or gastric cancer merits investigation. © 2017 UICC.

Combining Constitutively Active Rheb Expression and Chondroitinase Promotes Functional Axonal Regeneration after Cervical Spinal Cord Injury.

PubMed

Wu, Di; Klaw, Michelle C; Connors, Theresa; Kholodilov, Nikolai; Burke, Robert E; Côté, Marie-Pascale; Tom, Veronica J

2017-12-06

After spinal cord injury (SCI), severed axons in the adult mammalian CNS are unable to mount a robust regenerative response. In addition, the glial scar at the lesion site further restricts the regenerative potential of axons. We hypothesized that a combinatorial approach coincidentally targeting these obstacles would promote axonal regeneration. We combined (1) transplantation of a growth-permissive peripheral nerve graft (PNG) into an incomplete, cervical lesion cavity; (2) transduction of neurons rostral to the SCI site to express constitutively active Rheb (caRheb; a Ras homolog enriched in brain), a GTPase that directly activates the growth-promoting pathway mammalian target of rapamycin (mTOR) via AAV-caRheb injection; and (3) digestion of growth-inhibitory chondroitin sulfate proteoglycans within the glial scar at the distal PNG interface using the bacterial enzyme chondroitinase ABC (ChABC). We found that expressing caRheb in neurons post-SCI results in modestly yet significantly more axons regenerating across a ChABC-treated distal graft interface into caudal spinal cord than either treatment alone. Excitingly, we found that caRheb+ChABC treatment significantly potentiates the formation of synapses in the host spinal cord and improves the animals' ability to use the affected forelimb. Thus, this combination strategy enhances functional axonal regeneration following a cervical SCI. Copyright © 2017 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.

Whole-Genome Survey of the Putative ATP-Binding Cassette Transporter Family Genes in Vitis vinifera

PubMed Central

Çakır, Birsen; Kılıçkaya, Ozan

2013-01-01

The ATP-binding cassette (ABC) protein superfamily constitutes one of the largest protein families known in plants. In this report, we performed a complete inventory of ABC protein genes in Vitis vinifera, the whole genome of which has been sequenced. By comparison with ABC protein members of Arabidopsis thaliana, we identified 135 putative ABC proteins with 1 or 2 NBDs in V. vinifera. Of these, 120 encode intrinsic membrane proteins, and 15 encode proteins missing TMDs. V. vinifera ABC proteins can be divided into 13 subfamilies with 79 “full-size,” 41 “half-size,” and 15 “soluble” putative ABC proteins. The main feature of the Vitis ABC superfamily is the presence of 2 large subfamilies, ABCG (pleiotropic drug resistance and white-brown complex homolog) and ABCC (multidrug resistance-associated protein). We identified orthologs of V. vinifera putative ABC transporters in different species. This work represents the first complete inventory of ABC transporters in V. vinifera. The identification of Vitis ABC transporters and their comparative analysis with the Arabidopsis counterparts revealed a strong conservation between the 2 species. This inventory could help elucidate the biological and physiological functions of these transporters in V. vinifera. PMID:24244377

PubMed Central

Untch, Michael; Würstlein, Rachel; Marschner, Norbert; Lüftner, Diana; Augustin, Doris; Briest, Susanne; Ettl, Johannes; Haidinger, Renate; Müller, Lothar; Müller, Volkmar; Ruckhäberle, Eugen; Harbeck, Nadia; Thomssen, Christoph

2018-01-01

The fourth international advanced breast cancer consensus conference (ABC4) on the diagnosis and treatment of advanced breast cancer (ABC) headed by Professor Fatima Cardoso was once again held in Lisbon on November 2 – 4, 2017. To simplify matters, the abbreviation ABC will be used hereinafter in the text. In clinical practice, the abbreviation corresponds to metastatic breast cancer or locally far-advanced disease. This year the focus was on new developments in the treatment of ABC. Topics discussed included the importance of CDK4/6 inhibition in hormone receptor (HR)-positive ABC, the use of dual antibody blockade to treat HER2-positive ABC, PARP inhibition in triple-negative ABC and the potential therapeutic outcomes. Another major area discussed at the conference was BRCA-associated breast cancer, the treatment of cerebral metastasis, and individualized treatment decisions based on molecular testing (so-called precision medicine). As in previous years, close cooperation with representatives from patient organizations from around the world is an important aspect of the ABC conference. This cooperation was reinforced and expanded at the ABC4 conference. A global alliance was founded at the conclusion of the consensus conference, which aims to promote and coordinate the measures considered necessary by patient advocates worldwide. Because the panel of experts was composed of specialists from all over the world, it was inevitable that the ABC consensus also reflected country-specific features. As in previous years, a team of German breast cancer specialists who closely followed the consensus voting of the ABC panelists in Lisbon and intensively discussed the votes has therefore commented on the consensus in the context of the current German guidelines on the diagnosis and treatment of breast cancer 1 ,  2 used in clinical practice in Germany. The ABC consensus is based on the votes of the ABC panelists in Lisbon. PMID:29880982

Genome-wide identification, phylogenetic analysis, and expression profiles of ATP-binding cassette transporter genes in the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae).

PubMed

Xiao, Lin-Fan; Zhang, Wei; Jing, Tian-Xing; Zhang, Meng-Yi; Miao, Ze-Qing; Wei, Dan-Dan; Yuan, Guo-Rui; Wang, Jin-Jun

2018-03-01

The ATP-binding cassette (ABC) is the largest transporter gene family and the genes play key roles in xenobiotic resistance, metabolism, and development of all phyla. However, the specific functions of ABC gene families in insects is unclear. We report a genome-wide identification, phylogenetic, and transcriptional analysis of the ABC genes in the oriental fruit fly, Bactrocera dorsalis (Hendel). We identified a total of 47 ABC genes (BdABCs) from the transcriptomic and genomic databases of B. dorsalis and classified these genes into eight subfamilies (A-H), including 7 ABCAs, 7 ABCBs, 9 ABCCs, 2 ABCDs, 1 ABCE, 3 ABCFs, 15 ABCGs, and 3 ABCHs. Comparative phylogenetic analysis of the ABCs suggests an orthologous relationship between B. dorsalis and other insect species in which these genes have been related to pesticide resistance and essential biological processes. Comparison of transcriptome and relative expression patterns of BdABCs indicated diverse multifunctions within different B. dorsalis tissues. The expression of 4, 10, and 14 BdABCs from 18 BdABCs was significantly upregulated after exposure to LD 50 s of malathion, avermectin, and beta-cypermethrin, respectively. The maximum expression level of most BdABCs (including BdABCFs, BdABCGs, and BdABCHs) occurred at 48h post exposures, whereas BdABCEs peaked at 24h after treatment. Furthermore, RNA interference-mediated suppression of BdABCB7 resulted in increased toxicity of malathion against B. dorsalis. These data suggest that ABC transporter genes might play key roles in xenobiotic metabolism and biosynthesis in B. dorsalis. Copyright © 2017 Elsevier Inc. All rights reserved.

Regulation of the ATPase activity of ABCE1 from Pyrococcus abyssi by Fe-S cluster status and Mg²⁺: implication for ribosomal function.

PubMed

Sims, Lynn M; Igarashi, Robert Y

2012-08-15

Ribosomal function is dependent on multiple proteins. The ABCE1 ATPase, a unique ABC superfamily member that bears two Fe₄S₄ clusters, is crucial for ribosomal biogenesis and recycling. Here, the ATPase activity of the Pyrococcus abyssi ABCE1 (PabABCE1) was studied using both apo- (without reconstituted Fe-S clusters) and holo- (with full complement of Fe-S clusters reconstituted post-purification) forms, and is shown to be jointly regulated by the status of Fe-S clusters and Mg²⁺. Typically ATPases require Mg²⁺, as is true for PabABCE1, but Mg²⁺ also acts as a negative allosteric effector that modulates ATP affinity of PabABCE1. Physiological [Mg²⁺] inhibits the PabABCE1 ATPase (K(i) of ∼1 μM) for both apo- and holo-PabABCE1. Comparative kinetic analysis of Mg²⁺ inhibition shows differences in degree of allosteric regulation between the apo- and holo-PabABCE1 where the apparent ATP K(m) of apo-PabABCE1 increases >30-fold from ∼30 μM to over 1 mM with M²⁺. This effect would significantly convert the ATPase activity of PabABCE1 from being independent of cellular energy charge (φ) to being dependent on φ with cellular [Mg²⁺]. These findings uncover intricate overlapping effects by both [Mg²⁺] and the status of Fe-S clusters that regulate ABCE1's ATPase activity with implications to ribosomal function. Copyright © 2012 Elsevier Inc. All rights reserved.

LXR agonist treatment of blastic plasmacytoid dendritic cell neoplasm restores cholesterol efflux and triggers apoptosis

PubMed Central

Ceroi, Adam; Masson, David; Roggy, Anne; Roumier, Christophe; Chagué, Cécile; Gauthier, Thierry; Philippe, Laure; Lamarthée, Baptiste; Angelot-Delettre, Fanny; Bonnefoy, Francis; Perruche, Sylvain; Biichle, Sabeha; Preudhomme, Claude; Macintyre, Elisabeth; Lagrost, Laurent; Garnache-Ottou, Francine

2016-01-01

Blastic plasmacytoid dendritic cell (PDC) neoplasm (BPDCN) is an aggressive hematological malignancy with a poor prognosis that derives from PDCs. No consensus for optimal treatment modalities is available today and the full characterization of this leukemia is still emerging. We identified here a BPDCN-specific transcriptomic profile when compared with those of acute myeloid leukemia and T-acute lymphoblastic leukemia, as well as the transcriptomic signature of primary PDCs. This BPDCN gene signature identified a dysregulation of genes involved in cholesterol homeostasis, some of them being liver X receptor (LXR) target genes. LXR agonist treatment of primary BPDCN cells and BPDCN cell lines restored LXR target gene expression and increased cholesterol efflux via the upregulation of adenosine triphosphate–binding cassette (ABC) transporters, ABCA1 and ABCG1. LXR agonist treatment was responsible for limiting BPDCN cell proliferation and inducing intrinsic apoptotic cell death. LXR activation in BPDCN cells was shown to interfere with 3 signaling pathways associated with leukemic cell survival, namely: NF-κB activation, as well as Akt and STAT5 phosphorylation in response to the BPDCN growth/survival factor interleukin-3. These effects were increased by the stimulation of cholesterol efflux through a lipid acceptor, the apolipoprotein A1. In vivo experiments using a mouse model of BPDCN cell xenograft revealed a decrease of leukemic cell infiltration and BPDCN-induced cytopenia associated with increased survival after LXR agonist treatment. This demonstrates that cholesterol homeostasis is modified in BPDCN and can be normalized by treatment with LXR agonists which can be proposed as a new therapeutic approach. PMID:27702801

NtPDR3, an iron-deficiency inducible ABC transporter in Nicotiana tabacum.

PubMed

Ducos, Eric; Fraysse, Staffan; Boutry, Marc

2005-12-19

In plants, the ABC transporter PDR (pleiotropic drug resistance) subfamily is composed of approximately 15 genes, few of which have been analyzed. We have identified NtPDR3, a Nicotiana tabacum PDR gene belonging to a cluster for which no functional data was previously available. NtPDR3 was found to be induced in suspension cells treated with methyl jasmonate, salicylic acid, 1-naphthalene acetic acid, or cembrene, a macrocyclic diterpene. In agreement with the identification of a putative iron deficiency element in the NtPDR3 transcription promoter region, we found that iron deficiency in the culture medium induced NtPDR3 expression, thus suggesting a new function of the PDR transporter family.

Plasma membrane dynamics and tetrameric organisation of ABCG2 transporters in mammalian cells revealed by single particle imaging techniques.

PubMed

Wong, Kelvin; Briddon, Stephen J; Holliday, Nicholas D; Kerr, Ian D

2016-01-01

ABCG2 is one of three human ATP binding cassette (ABC) transporters involved in the export from cells of a chemically and structurally diverse range of compounds. This multidrug efflux capability, together with a broad tissue distribution in the body, means that ABCG2 exerts a range of effects on normal physiology such as kidney urate transport, as well as contributing towards the pharmacokinetic profiles of many exogenous drugs. The primary sequence of ABCG2 contains only half the number of domains required for a functioning ABC transporter and so it must oligomerise in order to function, yet its oligomeric state in intact cell membranes remains uncharacterized. We have analysed ABCG2 in living cell membranes using a combination of fluorescence correlation spectroscopy, photon counting histogram analysis, and stepwise photobleaching to demonstrate a predominantly tetrameric structure for ABCG2 in the presence or absence of transport substrates. These results provide the essential basis for exploring pharmacological manipulation of oligomeric state as a strategy to modulate ABCG2 activity in future selective therapeutics. Copyright © 2015 Elsevier B.V. All rights reserved.

SWIFT: Prospective 48-Week Study to Evaluate Efficacy and Safety of Switching to Emtricitabine/Tenofovir From Lamivudine/Abacavir in Virologically Suppressed HIV-1 Infected Patients on a Boosted Protease Inhibitor Containing Antiretroviral Regimen

PubMed Central

Campo, R.; DeJesus, E.; Bredeek, U. F.; Henry, K.; Khanlou, H.; Logue, K.; Brinson, C.; Benson, P.; Dau, L.; Wang, H.; White, K.; Flaherty, J.; Fralich, T.; Guyer, B.; Piontkowsky, D.

2013-01-01

Background. In the United States, emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) is a preferred nucleoside reverse transcriptase inhibitor (NRTI) backbone with lamivudine/abacavir (3TC/ABC) as a commonly used alternative. For patients infected with human immunodeficiency virus (HIV-1) virologically suppressed on a boosted protease inhibitor (PI) + 3TC/ABC regimen, the merits of switching to FTC/TDF as the NRTI backbone are unknown. Methods. SWIFT was a prospective, randomized, open-label 48-week study to evaluate efficacy and safety of switching to FTC/TDF. Subjects receiving 3TC/ABC + PI + ritonavir (RTV) with HIV-1 RNA < 200 c/mL ≥3 months were randomized to continue 3TC/ABC or switch to FTC/TDF. The primary endpoint was time to loss of virologic response (TLOVR) with noninferiority measured by delta of 12%. Virologic failure (VF) was defined as confirmed rebound or the last HIV-1 RNA measurement on study drug ≥200 c/mL. Results. In total, 311 subjects were treated in this study (155 to PI + RTV + FTC/TDF, 156 to PI + RTV + 3TC/ABC). Baseline characteristics were similar between the arms: 85% male, 28% black, median age, 46 years; and median CD4 532 cells/mm3. By TLOVR through week 48, switching to FTC/TDF was noninferior compared to continued 3TC/ABC (86.4% vs 83.3%, treatment difference 3.0% (95% confidence interval, −5.1% to 11.2%). Fewer subjects on FTC/TDF experienced VF (3 vs 11; P = .034). FTC/TDF showed greater declines in fasting low-density lipoproteins (LDL), total cholesterol (TC), and triglycerides (TG) with significant declines in LDL and TC beginning at week 12 with no TC/HDL ratio change. Switching to FTC/TDF showed improved NCEP thresholds for TC and TG and improved 10-year Framingham TC calculated scores. Decreased epidermal growth factor receptor (eGFR) was observed in both arms with a larger decrease in the FTC/TDF arm. Conclusions. Switching to FTC/TDF from 3TC/ABC maintained virologic suppression, had fewer VFs, improved lipid parameters and Framingham scores but decreased eGFR. ClinicalTrials.gov identifier. NCT00724711. PMID:23362296

The Function of UreB in Klebsiella aerogenes Urease†

PubMed Central

Carter, Eric L.; Boer, Jodi L.; Farrugia, Mark A.; Flugga, Nicholas; Towns, Christopher L.; Hausinger, Robert P.

2011-01-01

Urease from Klebsiella aerogenes is composed of three subunits (UreA, UreB, and UreC) which assemble into a (UreABC)3 quaternary structure. UreC harbors the dinuclear nickel active site, whereas the functions of UreA and UreB remain unknown. UreD and UreF accessory proteins previously were suggested to reposition UreB and increase exposure of the nascent urease active site, thus facilitating metallocenter assembly. In this study, cells were engineered to separately produce (UreAC)3 or UreB, and the purified proteins were characterized. Monomeric UreB spontaneously binds to the trimeric heterodimer of UreA plus UreC to form (UreABC*)3 apoprotein, as shown by gel filtration chromatography, integration of electrophoretic gel band intensities, and mass spectrometry. Similar to authentic urease apoprotein, active enzyme is produced by incubation of (UreABC*)3 with Ni2+ and bicarbonate. Conversely, UreBΔ1-19, lacking the 19 residue potential hinge and tether to UreC, does not form a complex with (UreAC)3 and yields negligible levels of active enzyme when incubated under activation conditions with (UreAC)3. Comparison of activities and nickel contents for (UreAC)3, (UreABC*)3, and (UreABC)3 samples treated with Ni2+ and bicarbonate and then desalted indicates that UreB facilitates efficient incorporation of the metal into the active site and protects the bound metal from chelation. Amylose resin pull-down studies reveal that MBP-UreD (a fusion of maltose binding protein with UreD) forms complexes with (UreABC)3, (UreAC)3, and UreB in vivo, but not in vitro. By contrast, MBP-UreD does not form an in vivo complex with UreBΔ1-19. The soluble MBP-UreD:UreF:UreG complex binds in vitro to (UreABC)3, but not to (UreAC)3 or UreB. Together these data demonstrate that UreB facilitates the interaction of urease with accessory proteins during metallocenter assembly, with the N-terminal hinge and tether region being specifically required for this process. In addition to its role in urease activation, UreB enhances the stability of UreC against proteolytic cleavage. PMID:21939280

On the Huygens absorbing boundary conditions for electromagnetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berenger, Jean-Pierre

A new absorbing boundary condition (ABC) is presented for the solution of Maxwell equations in unbounded spaces. Called the Huygens ABC, this condition is a generalization of two previously published ABCs, namely the multiple absorbing surfaces (MAS) and the re-radiating boundary condition (rRBC). The properties of the Huygens ABC are derived theoretically in continuous spaces and in the finite-difference (FDTD) discretized space. A solution is proposed to render the Huygens ABC effective for the absorption of evanescent waves. Numerical experiments with the FDTD method show that the effectiveness of the Huygens ABC is close to that of the PML ABCmore » in some realistic problems of numerical electromagnetics. It is also shown in the paper that a combination of the Huygens ABC with the PML ABC is very well suited to the solution of some particular problems.« less

Cisplatin and gemcitabine in patients with advanced biliary tract cancer (ABC) and persistent jaundice despite optimal stenting: Effective intervention in patients with luminal disease.

PubMed

Lamarca, Angela; Benafif, Sarah; Ross, Paul; Bridgewater, John; Valle, Juan W

2015-09-01

The advanced biliary tract cancer (ABC)-02 study established cisplatin and gemcitabine (CisGem) as a reference 1(st)-line regimen for patients with advanced/metastatic biliary tract cancer; patients with bilirubin ⩾ 1.5 × upper limit of normal (ULN) were excluded and there are few extant data for systemic treatment in the context of elevated bilirubin. Patients with ABC, receiving CisGem with a baseline bilirubin of ⩾ 1.5 × ULN were eligible for this retrospective analysis; response, toxicity and survival data were collected. Thirty-three patients of 545 screened; median age 59 years, range 23-79; 58% male, 58% with metastases (79% in the liver) of performance status (PS) 0 (33%), 1 (64%) or 2 (3%) were eligible. The median baseline bilirubin was 55 μmol/L (range 32-286); due to biliary tract obstruction (BTO, 76%) or liver metastases (LM, 24%). Toxicity was comparable to the ABC-02 study; bilirubin normalised in 64% during chemotherapy/follow-up. The median progression-free survival (PFS) was 6.9 months (95% confidence interval (CI): 4.4-9.0) and median overall survival (OS) 9.5 months (95% CI: 5.7-12.8). Patients with BTO had a longer PFS and OS than those with LM (7.0 versus 2.6 months; p = 0.1633 and 9.8 versus 4.4 months, hazard ratio (HR) 0.74; p = 0.465, respectively); not statistically significant (due to small sample size). Normalisation of bilirubin and completion of eight CisGem cycles were associated with longer OS (11.4 versus 2.9 months, HR 0.49; p = 0.08 and 15.2 versus 5.4 months, HR 0.12 p < 0.001, respectively). No difference in OS was shown between the bilirubin percentiles (for either PFS or OS). For PS 0-1 patients with ABC and high bilirubin due to luminal disease despite optimal stenting CisGem can be used safely with results similar to those in patients with normal bilirubin. Copyright © 2015 Elsevier Ltd. All rights reserved.

Investigating the compatibility of the biocontrol agent Clonostachys rosea IK726 with prodigiosin-producing Serratia rubidaea S55 and phenazine-producing Pseudomonas chlororaphis ToZa7.

PubMed

Kamou, Nathalie N; Dubey, Mukesh; Tzelepis, Georgios; Menexes, Georgios; Papadakis, Emmanouil N; Karlsson, Magnus; Lagopodi, Anastasia L; Jensen, Dan Funck

2016-05-01

This study was carried out to assess the compatibility of the biocontrol fungus Clonostachys rosea IK726 with the phenazine-producing Pseudomonas chlororaphis ToZa7 or with the prodigiosin-producing Serratia rubidaea S55 against Fusarium oxysporum f. sp. radicis-lycopersici. The pathogen was inhibited by both strains in vitro, whereas C. rosea displayed high tolerance to S. rubidaea but not to P. chlororaphis. We hypothesized that this could be attributed to the ATP-binding cassette (ABC) proteins. The results of the reverse transcription quantitative PCR showed an induction of seven genes (abcB1, abcB20, abcB26, abcC12, abcC12, abcG8 and abcG25) from subfamilies B, C and G. In planta experiments showed a significant reduction in foot and root rot on tomato plants inoculated with C. rosea and P. chlororaphis. This study demonstrates the potential for combining different biocontrol agents and suggests an involvement of ABC transporters in secondary metabolite tolerance in C. rosea.

VEGFR-1 Expressed by Malignant Melanoma-Initiating Cells Is Required for Tumor Growth

PubMed Central

Frank, Natasha Y.; Schatton, Tobias; Kim, Soo; Zhan, Qian; Wilson, Brian J.; Ma, Jie; Saab, Karim R.; Osherov, Veronika; Widlund, Hans R.; Gasser, Martin; Waaga-Gasser, Ana-Maria; Kupper, Thomas S.; Murphy, George F.; Frank, Markus H.

2011-01-01

Melanoma growth is driven by malignant melanoma-initiating cells (MMIC) identified by expression of the ATP-binding cassette (ABC) member ABCB5. ABCB5+ melanoma subpopulations have been shown to overexpress the vasculogenic differentiation markers CD144 (VE-cadherin) and TIE1 and are associated with CD31− vasculogenic mimicry (VM), an established biomarker associated with increased patient mortality. Here we identify a critical role for VEGFR-1 signaling in ABCB5+ MMIC-dependent VM and tumor growth. Global gene expression analyses, validated by mRNA and protein determinations, revealed preferential expression of VEGFR-1 on ABCB5+ tumor cells purified from clinical melanomas and established melanoma lines. In vitro, VEGF induced the expression of CD144 in ABCB5+ subpopulations that constitutively expressed VEGFR-1 but not in ABCB5− bulk populations that were predominantly VEGFR-1−. In vivo, melanoma-specific shRNA-mediated knockdown of VEGFR-1 blocked the development of ABCB5+ VM morphology and inhibited ABCB5+ VM-associated production of the secreted melanoma mitogen laminin. Moreover, melanoma-specific VEGFR-1 knockdown markedly inhibited tumor growth (by >90%). Our results show that VEGFR-1 function in MMIC regulates VM and associated laminin production and show that this function represents one mechanism through which MMICs promote tumor growth. PMID:21212411

VEGFR-1 expressed by malignant melanoma-initiating cells is required for tumor growth.

PubMed

Frank, Natasha Y; Schatton, Tobias; Kim, Soo; Zhan, Qian; Wilson, Brian J; Ma, Jie; Saab, Karim R; Osherov, Veronika; Widlund, Hans R; Gasser, Martin; Waaga-Gasser, Ana-Maria; Kupper, Thomas S; Murphy, George F; Frank, Markus H

2011-02-15

Melanoma growth is driven by malignant melanoma-initiating cells (MMIC) identified by expression of the ATP-binding cassette (ABC) member ABCB5. ABCB5(+) melanoma subpopulations have been shown to overexpress the vasculogenic differentiation markers CD144 (VE-cadherin) and TIE1 and are associated with CD31(-) vasculogenic mimicry (VM), an established biomarker associated with increased patient mortality. Here we identify a critical role for VEGFR-1 signaling in ABCB5(+) MMIC-dependent VM and tumor growth. Global gene expression analyses, validated by mRNA and protein determinations, revealed preferential expression of VEGFR-1 on ABCB5(+) tumor cells purified from clinical melanomas and established melanoma lines. In vitro, VEGF induced the expression of CD144 in ABCB5(+) subpopulations that constitutively expressed VEGFR-1 but not in ABCB5(-) bulk populations that were predominantly VEGFR-1(-). In vivo, melanoma-specific shRNA-mediated knockdown of VEGFR-1 blocked the development of ABCB5(+) VM morphology and inhibited ABCB5(+) VM-associated production of the secreted melanoma mitogen laminin. Moreover, melanoma-specific VEGFR-1 knockdown markedly inhibited tumor growth (by > 90%). Our results show that VEGFR-1 function in MMIC regulates VM and associated laminin production and show that this function represents one mechanism through which MMICs promote tumor growth. ©2011 AACR.

[Impact of siRNA-mediated down-regulation of CD147 on human breast cancer cells].

PubMed

Li, Zhenqian; Li, Daoming; Li, Jiangwei; Huang, Pei; Qin, Hui

2015-10-01

To investigate the influence of siRNA-mediated down-regulation of CD147 on growth, proliferation and movement of human breast cancer cell line MDA-MB-231. The protein expression of CD147, MMP-2 and TIMP-2 of the MDA-MB-231 cells were analyzed by ABC. Lentiviral expression vector of CD147 gene was constructed and transfected into MDA-MB-231 cells. RT-PCR and Western blot were used to detect the mRNA and protein level changes of CD147 genes to identify the optimal time point, followed by detection of changes of mRNA and protein expression of MMP-2 and TIMP-2 genes. CCK-8 reagent method and cell scratch test were used to detect the proliferation and migration change of MDA-MB-231 cells. The nude mouse model of breast cancer by hypodermic injection with MDA-MB-231 cells was established to document the effect of CD147 siRNA on the tumor transplants. After transfection of lentiviral expression vector of CD147 gene, protein of CD147, MMP-2 and TIMP-2 were weakly or negative expressed, significantly weaker than those of control group (P < 0.01). After 72 hours of transfection, average down-regulation rate of CD147 and MMP-2 were 96.03% ± 0.84% and 96.03% ± 0.84%, respectively. Both CD147 mRNA and MMP-2 mRNA expression were down-regulated (P < 0.05), while TIMP-2 mRNA expression showed no significant deference (P > 0.05). No less than 2 days after transfection, cell growth of MDA-MB-231 cell line was found significantly inhibited (P < 0.05). After 24 hours of transection, average migration distance of MDA-MB-231 cell line and control group were (0.64 ± 0.12) mm and (4.69 ± 0.85) mm, respectively, which indicated a lower migrate speed. Down regulation of CD147 led to reduction of volume and mass of nude mouses. The growth of the carcinoma transplant was inhibited upon siRNA-mediated down-regulation of CD147 (P < 0.05), with an average tumor mass of (1.85 ± 0.98) g and both reduction of tumor size and tumor mass. CD147 may alter the MMP-2/TIMP-2 balance in MDA-MB-231 cells. CD147 gene silencing inhibits the proliferation and migration of MDA-MB-231 cells and the growth of carcinoma transplants in nude mice.

The E3 ubiquitin ligase, HECTD1, is involved in ABCA1-mediated cholesterol export from macrophages.

PubMed

Aleidi, Shereen M; Yang, Alryel; Sharpe, Laura J; Rao, Geetha; Cochran, Blake J; Rye, Kerry-Anne; Kockx, Maaike; Brown, Andrew J; Gelissen, Ingrid C

2018-04-01

The ABC lipid transporters, ABCA1 and ABCG1, are essential for maintaining lipid homeostasis in cells such as macrophages by exporting excess cholesterol to extracellular acceptors. These transporters are highly regulated at the post-translational level, including protein ubiquitination. Our aim was to investigate the role of the E3 ubiquitin ligase HECTD1, recently identified as associated with ABCG1, on ABCG1 and ABCA1 protein levels and cholesterol export function. Here, we show that HECTD1 protein is widely expressed in a range of human and murine primary cells and cell lines, including macrophages, neuronal cells and insulin secreting β-cells. siRNA knockdown of HECTD1 unexpectedly decreased overexpressed ABCG1 protein levels and cell growth, but increased native ABCA1 protein in CHO-K1 cells. Knockdown of HECTD1 in unloaded THP-1 macrophages did not affect ABCG1 but significantly increased ABCA1 protein levels, in wild-type as well as THP-1 cells that do not express ABCG1. Cholesterol export from macrophages to apoA-I over time was increased after knockdown of HECTD1, however these effects were not sustained in cholesterol-loaded cells. In conclusion, we have identified a new candidate, the E3 ubiquitin ligase HECTD1, that may be involved in the regulation of ABCA1-mediated cholesterol export from unloaded macrophages to apoA-I. The exact mechanism by which this ligase affects this pathway remains to be elucidated. Copyright © 2018 Elsevier B.V. All rights reserved.

The helicase HAGE expressed by malignant melanoma-initiating cells is required for tumor cell proliferation in vivo.

PubMed

Linley, Adam J; Mathieu, Morgan G; Miles, Amanda K; Rees, Robert C; McArdle, Stephanie E B; Regad, Tarik

2012-04-20

Malignant melanoma-initiating cells (MMIC) are a subpopulation of cells responsible for melanoma tumor growth and progression. They are defined by the expression of the ATP-binding cassette (ABC) subfamily B member 5 (ABCB5). Here, we identified a critical role for the DEAD-box helicase antigen (HAGE) in ABCB5+ MMIC-dependent tumorigenesis and show that HAGE-specific inactivation inhibits melanoma tumor growth mediated by this tumor-initiating population. Knockdown of HAGE led to a significant decrease in RAS protein expression with a concomitant decrease in activation of the AKT and ERK signaling pathways implicated to play an important role in melanoma progression. To confirm that the reduction in NRAS (Neuroblastoma RAS) expression was dependent on the HAGE helicase activity, we showed that NRAS, effectively silenced by siRNA, could be rescued by reintroduction of HAGE in cells lacking HAGE. Furthermore, we provide a mechanism by which HAGE promotes NRAS unwinding in vitro. We also observed using tumor transplantation in Non-obese diabetic/severe combined immunodeficiency mice that the HAGE knockdown in a ABCB5+ melanoma cell line displayed a significant decrease in tumor growth and compared with the control. Our results suggest that the helicase HAGE is required for ABCB5+ MMIC-dependent tumor growth through promoting RAS protein expression and that cancer therapies targeting HAGE helicase may have broad applications for treating malignant melanoma and potentially other cancer types.

The Helicase HAGE Expressed by Malignant Melanoma-Initiating Cells Is Required for Tumor Cell Proliferation in Vivo*

PubMed Central

Linley, Adam J.; Mathieu, Morgan G.; Miles, Amanda K.; Rees, Robert C.; McArdle, Stephanie E. B.; Regad, Tarik

2012-01-01

Malignant melanoma-initiating cells (MMIC) are a subpopulation of cells responsible for melanoma tumor growth and progression. They are defined by the expression of the ATP-binding cassette (ABC) subfamily B member 5 (ABCB5). Here, we identified a critical role for the DEAD-box helicase antigen (HAGE) in ABCB5+ MMIC-dependent tumorigenesis and show that HAGE-specific inactivation inhibits melanoma tumor growth mediated by this tumor-initiating population. Knockdown of HAGE led to a significant decrease in RAS protein expression with a concomitant decrease in activation of the AKT and ERK signaling pathways implicated to play an important role in melanoma progression. To confirm that the reduction in NRAS (Neuroblastoma RAS) expression was dependent on the HAGE helicase activity, we showed that NRAS, effectively silenced by siRNA, could be rescued by reintroduction of HAGE in cells lacking HAGE. Furthermore, we provide a mechanism by which HAGE promotes NRAS unwinding in vitro. We also observed using tumor transplantation in Non-obese diabetic/severe combined immunodeficiency mice that the HAGE knockdown in a ABCB5+ melanoma cell line displayed a significant decrease in tumor growth and compared with the control. Our results suggest that the helicase HAGE is required for ABCB5+ MMIC-dependent tumor growth through promoting RAS protein expression and that cancer therapies targeting HAGE helicase may have broad applications for treating malignant melanoma and potentially other cancer types. PMID:22393060

Natural lignans from Arctium lappa modulate P-glycoprotein efflux function in multidrug resistant cancer cells.

PubMed

Su, Shan; Cheng, Xinlai; Wink, Michael

2015-02-15

Arctium lappa is a well-known traditional medicinal plant in China (TCM) and Europe that has been used for thousands of years to treat arthritis, baldness or cancer. The plant produces lignans as secondary metabolites which have a wide range of bioactivities. Yet, their ability to reverse multidrug resistance (MDR) in cancer cells has not been explored. In this study, we isolated six lignans from A. lappa seeds, namely arctigenin, matairesinol, arctiin, (iso)lappaol A, lappaol C, and lappaol F. The MDR reversal potential of the isolated lignans and the underlying mechanism of action were studied using two MDR cancer cell lines, CaCo2 and CEM/ADR 5000 which overexpress P-gp and other ABC transporters. In two-drug combinations of lignans with the cytotoxic doxorubicin, all lignans exhibited synergistic effects in CaCo2 cells and matairesinol, arctiin, lappaol C and lappaol F display synergistic activity in CEM/ADR 5000 cells. Additionally, in three-drug combinations of lignans with the saponin digitonin and doxorubicin MDR reversal activity was even stronger enhanced. The lignans can increase the retention of the P-gp substrate rhodamine 123 in CEM/ADR 5000 cells, indicating that lignans can inhibit the activity of P-gp. Our study provides a first insight into the potential chemosensitizing activity of a series of natural lignans, which might be candidates for developing novel adjuvant anticancer agents. Copyright © 2015 Elsevier GmbH. All rights reserved.

Human Prostate Side Population Cells Demonstrate Stem Cell Properties in Recombination with Urogenital Sinus Mesenchyme

PubMed Central

Foster, Barbara A.; Gangavarapu, Kalyan J.; Mathew, Grinu; Azabdaftari, Gissou; Morrison, Carl D.; Miller, Austin; Huss, Wendy J.

2013-01-01

Stem cell enrichment provides a tool to examine prostate stem cells obtained from benign and malignant tissue. Functional assays can enrich stem cells based on common stem cell phenotypes, such as high ATP binding cassette (ABC) transporter mediated efflux of Hoechst substrates (side population assay). This functional assay is based upon mechanisms that protect cells from environmental insult thus contributing to the survival and protection of the stem cell population. We have isolated and analyzed cells digested from twelve clinical prostate specimens based on the side population assay. Prostate stem cell properties of the isolated cells were tested by serial recombination with rat urogenital mesenchyme. Recombinants with side population cells demonstrate an increase in the frequency of human ductal growth and the number of glands per recombinant when compared to recombinants with non-side population cells. Isolated cells were capable of prostatic growth for up to three generations in the recombination assay with as little as 125 sorted prostate cells. The ability to reproducibly use cells isolated by fluorescence activated cell sorting from human prostate tissue is an essential step to a better understanding of human prostate stem cell biology. ABC transporter G2 (ABCG2) was expressed in recombinants from side population cells indicating the side population cells have self-renewal properties. Epithelial cell differentiation of recombinants was determined by immunohistochemical analysis for expression of the basal, luminal, and neuroendocrine markers, p63, androgen receptor, prostate specific antigen, and chromogranin A, respectively. Thus, the ABCG2 expressing side population demonstrates multipotency and self-renewal properties indicating stem cells are within this population. PMID:23383057

50 CFR 622.60 - Adjustment of management measures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... markings and identification, allowable biological catch (ABC) and ABC control rules, rebuilding plans, sale... harvested shrimp (maintaining shrimp in whole condition, use as bait), target effort and fishing mortality... identification, vessel markings and identification, ABC and ABC control rules, rebuilding plans, sale and...

50 CFR 622.60 - Adjustment of management measures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... markings and identification, allowable biological catch (ABC) and ABC control rules, rebuilding plans, sale... harvested shrimp (maintaining shrimp in whole condition, use as bait), target effort and fishing mortality... identification, vessel markings and identification, ABC and ABC control rules, rebuilding plans, sale and...

Enhancement of Microbial Biodesulfurization via Genetic Engineering and Adaptive Evolution

PubMed Central

Wang, Jia; Butler, Robert R.; Wu, Fan; Pombert, Jean-François; Kilbane, John J.; Stark, Benjamin C.

2017-01-01

In previous work from our laboratories a synthetic gene encoding a peptide (“Sulpeptide 1” or “S1”) with a high proportion of methionine and cysteine residues had been designed to act as a sulfur sink and was inserted into the dsz (desulfurization) operon of Rhodococcus erythropolis IGTS8. In the work described here this construct (dszAS1BC) and the intact dsz operon (dszABC) cloned into vector pRESX under control of the (Rhodococcus) kstD promoter were transformed into the desulfurization-negative strain CW25 of Rhodococcus qingshengii. The resulting strains (CW25[pRESX-dszABC] and CW25[pRESX-dszAS1BC]) were subjected to adaptive selection by repeated passages at log phase (up to 100 times) in minimal medium with dibenzothiophene (DBT) as sole sulfur source. For both strains DBT metabolism peaked early in the selection process and then decreased, eventually averaging four times that of the initial transformed cells; the maximum specific activity achieved by CW25[pRESX-dszAS1BC] exceeded that of CW25[pRESX-dszABC]. Growth rates increased by 7-fold (CW25[pRESX-dszABC]) and 13-fold (CW25[pRESX-dszAS1BC]) and these increases were stable. The adaptations of CW25[pRESX-dszAS1BC] were correlated with a 3-5X increase in plasmid copy numbers from those of the initial transformed cells; whole genome sequencing indicated that during its selection processes no mutations occurred to any of the dsz, S1, or other genes and promoters involved in sulfur metabolism, stress response, or DNA methylation, and that the effect of the sulfur sink produced by S1 is likely very small compared to the cells’ overall cysteine and methionine requirements. Nevertheless, a combination of genetic engineering using sulfur sinks and increasing Dsz capability with adaptive selection may be a viable strategy to increase biodesulfurization ability. PMID:28060828

Oxidative Stress in HIV Infection and Alcohol Use: Role of Redox Signals in Modulation of Lipid Rafts and ATP-Binding Cassette Transporters.

PubMed

Thangavel, Samikkannu; Mulet, Carmen T; Atluri, Venkata S R; Agudelo, Marisela; Rosenberg, Rhonda; Devieux, Jessy G; Nair, Madhavan P N

2018-02-01

Human immunodeficiency virus (HIV) infection induces oxidative stress and alcohol use accelerates disease progression, subsequently causing immune dysfunction. However, HIV and alcohol impact on lipid rafts-mediated immune dysfunction remains unknown. In this study, we investigate the modulation by which oxidative stress induces reactive oxygen species (ROS) affecting redox expression, lipid rafts caveiloin-1, ATP-binding cassette (ABC) transporters, and transcriptional sterol regulatory element-binding protein (SREBP) gene and protein modification and how these mechanisms are associated with arachidonic acid (AA) metabolites in HIV positive alcohol users, and how they escalate immune dysfunction. In both alcohol using HIV-positive human subjects and in vitro studies of alcohol with HIV-1 gp120 protein in peripheral blood mononuclear cells, increased ROS production significantly affected redox expression in glutathione synthetase (GSS), super oxide dismutase (SOD), and glutathione peroxidase (GPx), and subsequently impacted lipid rafts Cav-1, ABC transporters ABCA1, ABCG1, ABCB1, and ABCG4, and SREBP transcription. The increased level of rate-limiting enzyme 3-hydroxy-3-methylglutaryl HMG-CoA reductase (HMGCR), subsequently, inhibited 7-dehydrocholesterol reductase (DHCR-7). Moreover, the expression of cyclooxygenase-2 (COX-2) and lipoxygenase-5 (5-LOX) mRNA and protein modification tentatively increased the levels of prostaglandin E2 synthases (PGE 2 ) in plasma when compared with either HIV or alcohol alone. This article suggests for the first time that the redox inhibition affects lipid rafts, ABC-transporter, and SREBP transcription and modulates AA metabolites, serving as an important intermediate signaling network during immune cell dysfunction in HIV-positive alcohol users. These findings indicate that HIV infection induces oxidative stress and redox inhibition, affecting lipid rafts and ABC transports, subsequently upregulating AA metabolites and leading to immune toxicity, and further exacerbation with alcohol use. Antioxid. Redox Signal. 28, 324-337.

Deciphering the Routes of invasion of Drosophila suzukii by Means of ABC Random Forest.

PubMed

Fraimout, Antoine; Debat, Vincent; Fellous, Simon; Hufbauer, Ruth A; Foucaud, Julien; Pudlo, Pierre; Marin, Jean-Michel; Price, Donald K; Cattel, Julien; Chen, Xiao; Deprá, Marindia; François Duyck, Pierre; Guedot, Christelle; Kenis, Marc; Kimura, Masahito T; Loeb, Gregory; Loiseau, Anne; Martinez-Sañudo, Isabel; Pascual, Marta; Polihronakis Richmond, Maxi; Shearer, Peter; Singh, Nadia; Tamura, Koichiro; Xuéreb, Anne; Zhang, Jinping; Estoup, Arnaud

2017-04-01

Deciphering invasion routes from molecular data is crucial to understanding biological invasions, including identifying bottlenecks in population size and admixture among distinct populations. Here, we unravel the invasion routes of the invasive pest Drosophila suzukii using a multi-locus microsatellite dataset (25 loci on 23 worldwide sampling locations). To do this, we use approximate Bayesian computation (ABC), which has improved the reconstruction of invasion routes, but can be computationally expensive. We use our study to illustrate the use of a new, more efficient, ABC method, ABC random forest (ABC-RF) and compare it to a standard ABC method (ABC-LDA). We find that Japan emerges as the most probable source of the earliest recorded invasion into Hawaii. Southeast China and Hawaii together are the most probable sources of populations in western North America, which then in turn served as sources for those in eastern North America. European populations are genetically more homogeneous than North American populations, and their most probable source is northeast China, with evidence of limited gene flow from the eastern US as well. All introduced populations passed through bottlenecks, and analyses reveal five distinct admixture events. These findings can inform hypotheses concerning how this species evolved between different and independent source and invasive populations. Methodological comparisons indicate that ABC-RF and ABC-LDA show concordant results if ABC-LDA is based on a large number of simulated datasets but that ABC-RF out-performs ABC-LDA when using a comparable and more manageable number of simulated datasets, especially when analyzing complex introduction scenarios. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Development of a practical costing method for hospitals.

PubMed

Cao, Pengyu; Toyabe, Shin-Ichi; Akazawa, Kouhei

2006-03-01

To realize an effective cost control, a practical and accurate cost accounting system is indispensable in hospitals. In traditional cost accounting systems, the volume-based costing (VBC) is the most popular cost accounting method. In this method, the indirect costs are allocated to each cost object (services or units of a hospital) using a single indicator named a cost driver (e.g., Labor hours, revenues or the number of patients). However, this method often results in rough and inaccurate results. The activity based costing (ABC) method introduced in the mid 1990s can prove more accurate results. With the ABC method, all events or transactions that cause costs are recognized as "activities", and a specific cost driver is prepared for each activity. Finally, the costs of activities are allocated to cost objects by the corresponding cost driver. However, it is much more complex and costly than other traditional cost accounting methods because the data collection for cost drivers is not always easy. In this study, we developed a simplified ABC (S-ABC) costing method to reduce the workload of ABC costing by reducing the number of cost drivers used in the ABC method. Using the S-ABC method, we estimated the cost of the laboratory tests, and as a result, similarly accurate results were obtained with the ABC method (largest difference was 2.64%). Simultaneously, this new method reduces the seven cost drivers used in the ABC method to four. Moreover, we performed an evaluation using other sample data from physiological laboratory department to certify the effectiveness of this new method. In conclusion, the S-ABC method provides two advantages in comparison to the VBC and ABC methods: (1) it can obtain accurate results, and (2) it is simpler to perform. Once we reduce the number of cost drivers by applying the proposed S-ABC method to the data for the ABC method, we can easily perform the cost accounting using few cost drivers after the second round of costing.

Weight and lean body mass change with antiretroviral initiation and impact on bone mineral density.

PubMed

Erlandson, Kristine M; Kitch, Douglas; Tierney, Camlin; Sax, Paul E; Daar, Eric S; Tebas, Pablo; Melbourne, Kathleen; Ha, Belinda; Jahed, Nasreen C; McComsey, Grace A

2013-08-24

To compare the effect that initiating different antiretroviral therapy (ART) regimens has on weight, BMI, and lean body mass (LBM) and explore how changes in body composition are associated with bone mineral density (BMD). A5224s was a sub-study of A5202, a prospective trial of 1857 ART-naive participants randomized to blinded abacavir-lamivudine (ABC/3TC) or tenofovir DF-emtricitabine (TDF/FTC) with open-label efavirenz (EFV) or atazanavir-ritonavir (ATV/r). All participants underwent dual-energy absorptiometry (DXA) and abdominal computed tomography for body composition. Analyses used two-sample t-tests and linear regression. A5224s included 269 participants: 85% men, 47% white non-Hispanic, median age 38 years, HIV-1 RNA 4.6 log10 copies/ml, and CD4 cell count 233 cells/μl. Overall, significant gains occurred in weight, BMI, and LBM at 96 weeks post-randomization (all P<0.001). Assignment to ATV/r (vs. EFV) resulted in significantly greater weight (mean difference 3.35 kg) and BMI gain (0.88 kg/m; both P=0.02), but not LBM (0.67 kg; P=0.15), whereas ABC/3TC and TDF/FTC were not significantly different (P≥0.10). In multivariable analysis, only lower baseline CD4 cell count and higher HIV-1 RNA were associated with greater increase in weight, BMI, or LBM. In multivariable analyses, increased LBM was associated with an increased hip BMD. ABC/3TC vs. TDF/FTC did not differ in change in weight, BMI, or LBM; ATV/r vs. EFV resulted in greater weight and BMI gain but not LBM. A positive association between increased LBM and increased hip BMD should be further investigated through prospective interventional studies to verify the impact of increased LBM on hip BMD.

Telangiectatic osteosarcoma: Outcome analyses and a diagnostic model for differentiation from aneurysmal bone cyst.

PubMed

Yin, Jun-Qiang; Fu, Yi-Wei; Xie, Xian-Biao; Cheng, Xiao-Yu; Yang, Xiao-Yu; Liu, Wei-Hai; Tu, Jian; Gao, Zhen-Hua; Shen, Jing-Nan

2018-06-01

Telangiectatic osteosarcoma (TOS), a rare variant of osteosarcoma, may be easily misdiagnosed as aneurysmal bone cyst (ABC). The aims of this study were to investigate the diagnostic and prognostic factors of TOS by reviewing our experience with TOS and to develop a diagnostic model that may distinguish TOS from ABC. We identified 51 cases of TOS treated at the First Affiliated Hospital of Sun Yat-Sen University from March 2001 to January 2016 and reviewed their records, imaging information and pathological studies. A diagnostic model was developed to differentiate TOS and ABC by Bayes discriminant analysis and was evaluated. The log-rank test was used to analyze the prognostic factors of TOS and to compare the outcome differences between TOS and other high-grade osteosarcoma subtypes. The multi-disciplinary diagnostic method employed that combined clinical, imaging, and pathological studies enhanced the diagnostic accuracy. Age 18 years or younger and pathologic fracture were more common among the TOS patients than among the ABC patients (P = .004 and .005, respectively). The average white blood cell (WBC), platelet, lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) values of the TOS patients were higher than those of the ABC patients ( P = .002, .003, .007, and .007, respectively). Our diagnostic model, including the aforementioned factors, accurately predicted 62% and 78% of the TOS patients in the training and validation sets, respectively. The 5-year estimates of event-free survival and overall survival of the TOS patients were 52.5 ± 9.4% and 54.9 ± 8.8%, respectively, which were similar to those of patients with other osteosarcoma subtypes ( P = .950 and .615, respectively). Tumor volume and the LDH level were predictive prognostic factors ( P = .040 and .044) but not the presence of pathologic fracture or misdiagnosis ( P = .424 and .632, all respectively). The multi-disciplinary diagnostic method and diagnostic model based on predictive factors, i.e. , age, the presence of pathologic fracture, and platelet, LDH, ALP and WBC levels, aided the differentiation of TOS and ABC. Smaller tumors and normal LDH levels were associated with better outcomes.

A Neisseria meningitidis fbpABC mutant is incapable of using nonheme iron for growth.

PubMed

Khun, H H; Kirby, S D; Lee, B C

1998-05-01

The neisserial fbpABC locus has been proposed to act as an iron-specific ABC transporter system. To confirm this assigned function, we constructed an fbpABC mutant in Neisseria meningitidis by insertional inactivation of fbpABC with a selectable antibiotic marker. The mutant was unable to use iron supplied from human transferrin, human lactoferrin, or iron chelates. However, the use of iron from heme and human hemoglobin was unimpaired. These results support the obligatory participation of fbpABC in neisserial periplasmic iron transport and do not indicate a role for this genetic locus in the heme iron pathway.

A Neisseria meningitidis fbpABC Mutant Is Incapable of Using Nonheme Iron for Growth

PubMed Central

Khun, Heng H.; Kirby, Shane D.; Lee, B. Craig

1998-01-01

The neisserial fbpABC locus has been proposed to act as an iron-specific ABC transporter system. To confirm this assigned function, we constructed an fbpABC mutant in Neisseria meningitidis by insertional inactivation of fbpABC with a selectable antibiotic marker. The mutant was unable to use iron supplied from human transferrin, human lactoferrin, or iron chelates. However, the use of iron from heme and human hemoglobin was unimpaired. These results support the obligatory participation of fbpABC in neisserial periplasmic iron transport and do not indicate a role for this genetic locus in the heme iron pathway. PMID:9573125

Chromosomal Fragmentation in "Escherichia Coli": Its Absence in "mutT" Mutants and Its Mechanisms in "seqA" Mutants

ERIC Educational Resources Information Center

Rotman, Ella Rose

2009-01-01

Chromosomal fragmentation in "Escherichia coli" is a lethal event for the cell unless mended by the recombinational repair proteins RecA, RecBCD, and RuvABC. Certain mutations exacerbate problems that cause the cell to be dependent on the recombinational repair proteins for viability. We tested whether the absence of the MutT protein caused…

Modified artificial bee colony for the vehicle routing problems with time windows.

PubMed

Alzaqebah, Malek; Abdullah, Salwani; Jawarneh, Sana

2016-01-01

The natural behaviour of the honeybee has attracted the attention of researchers in recent years and several algorithms have been developed that mimic swarm behaviour to solve optimisation problems. This paper introduces an artificial bee colony (ABC) algorithm for the vehicle routing problem with time windows (VRPTW). A Modified ABC algorithm is proposed to improve the solution quality of the original ABC. The high exploration ability of the ABC slows-down its convergence speed, which may due to the mechanism used by scout bees in replacing abandoned (unimproved) solutions with new ones. In the Modified ABC a list of abandoned solutions is used by the scout bees to memorise the abandoned solutions, then the scout bees select a solution from the list based on roulette wheel selection and replace by a new solution with random routs selected from the best solution. The performance of the Modified ABC is evaluated on Solomon benchmark datasets and compared with the original ABC. The computational results demonstrate that the Modified ABC outperforms the original ABC also produce good solutions when compared with the best-known results in the literature. Computational investigations show that the proposed algorithm is a good and promising approach for the VRPTW.

Three dimensional magnetohydrodynamic simulation of linearly polarised Alfven wave dynamics in Arnold-Beltrami-Childress magnetic field

NASA Astrophysics Data System (ADS)

Tsiklauri, David

2015-04-01

Previous studies (e.g., Malara et al., Astrophys. J. 533, 523 (2000)) considered small-amplitude Alfven wave (AW) packets in Arnold-Beltrami-Childress (ABC) magnetic field using WKB approximation. They draw a distinction between 2D AW dissipation via phase mixing and 3D AW dissipation via exponentially divergent magnetic field lines. In the former case, AW dissipation time scales as S 1/3 and in the latter as log(S) , where S is the Lundquist number. In this work [1], linearly polarised Alfven wave dynamics in ABC magnetic field via direct 3D magnetohydrodynamic (MHD) numerical simulation is studied for the first time. A Gaussian AW pulse with length-scale much shorter than ABC domain length and a harmonic AW with wavelength equal to ABC domain length are studied for four different resistivities. While it is found that AWs dissipate quickly in the ABC field, contrary to an expectation, it is found the AW perturbation energy increases in time. In the case of the harmonic AW, the perturbation energy growth is transient in time, attaining peaks in both velocity and magnetic perturbation energies within timescales much smaller than the resistive time. In the case of the Gaussian AW pulse, the velocity perturbation energy growth is still transient in time, attaining a peak within few resistive times, while magnetic perturbation energy continues to grow. It is also shown that the total magnetic energy decreases in time and this is governed by the resistive evolution of the background ABC magnetic field rather than AW damping. On contrary, when the background magnetic field is uniform, the total magnetic energy decrease is prescribed by AW damping, because there is no resistive evolution of the background. By considering runs with different amplitudes and by analysing the perturbation spectra, possible dynamo action by AW perturbation-induced peristaltic flow and inverse cascade of magnetic energy have been excluded. Therefore, the perturbation energy growth is attributed to a new instability. The growth rate appears to be dependent on the value of the resistivity and the spatial scale of the AW disturbance. Thus, when going beyond WKB approximation, AW damping, described by full MHD equations, does not guarantee decrease of perturbation energy. This has implications for the MHD wave plasma heating in exponentially divergent magnetic fields. [1] D. Tsiklauri, Phys. Plasmas 21, 052902 (2014); http://dx.doi.org/10.1063/1.4875920 This research is funded by the Leverhulme Trust Research Project Grant RPG-311

ATP7A is a novel target of retinoic acid receptor β2 in neuroblastoma cells

PubMed Central

Bohlken, A; Cheung, B B; Bell, J L; Koach, J; Smith, S; Sekyere, E; Thomas, W; Norris, M; Haber, M; Lovejoy, D B; Richardson, D R; Marshall, G M

2009-01-01

Increased retinoic acid receptor β (RARβ2) gene expression is a hallmark of cancer cell responsiveness to retinoid anticancer effects. Moreover, low basal or induced RARβ2 expression is a common feature of many human cancers, suggesting that RARβ2 may act as a tumour suppressor gene in the absence of supplemented retinoid. We have previously shown that low RARβ2 expression is a feature of advanced neuroblastoma. Here, we demonstrate that the ABC domain of the RARβ2 protein alone was sufficient for the growth inhibitory effects of RARβ2 on neuroblastoma cells. ATP7A, the copper efflux pump, is a retinoid-responsive gene, was upregulated by ectopic overexpression of RARβ2. The ectopic overexpression of the RARβ2 ABC domain was sufficient to induce ATP7A expression, whereas, RARβ2 siRNA blocked the induction of ATP7A expression in retinoid-treated neuroblastoma cells. Forced downregulation of ATP7A reduced copper efflux and increased viability of retinoid-treated neuroblastoma cells. Copper supplementation enhanced cell growth and reduced retinoid-responsiveness, whereas copper chelation reduced the viability and proliferative capacity. Taken together, our data demonstrates ATP7A expression is regulated by retinoic acid receptor β and it has effects on intracellular copper levels, revealing a link between the anticancer action of retinoids and copper metabolism. PMID:19127267

Object Detection Based on Template Matching through Use of Best-So-Far ABC

PubMed Central

2014-01-01

Best-so-far ABC is a modified version of the artificial bee colony (ABC) algorithm used for optimization tasks. This algorithm is one of the swarm intelligence (SI) algorithms proposed in recent literature, in which the results demonstrated that the best-so-far ABC can produce higher quality solutions with faster convergence than either the ordinary ABC or the current state-of-the-art ABC-based algorithm. In this work, we aim to apply the best-so-far ABC-based approach for object detection based on template matching by using the difference between the RGB level histograms corresponding to the target object and the template object as the objective function. Results confirm that the proposed method was successful in both detecting objects and optimizing the time used to reach the solution. PMID:24812556

Attenuated mutant strain of Salmonella Typhimurium lacking the ZnuABC transporter contrasts tumor growth promoting anti-cancer immune response.

PubMed

Chirullo, Barbara; Ammendola, Serena; Leonardi, Leonardo; Falcini, Roberto; Petrucci, Paola; Pistoia, Claudia; Vendetti, Silvia; Battistoni, Andrea; Pasquali, Paolo

2015-07-10

Salmonella Typhimurium has been shown to be highly effective as antitumor agent. The aim of this study was to investigate the tumor targeting efficacy and the mechanism of action of a specific attenuated mutant strain of Salmonella Typhimurium (STM) devoid of the whole operon coding for the high-affinity zinc transporter ZnuABC, which is required for bacterial growth in environments poor in zinc and for conferring full virulence to different Gram-negative pathogens.We showed that STM is able to penetrate and replicate into tumor cells in in vitro and in vivo models. The subcutaneous administration of STM in mammary adenocarcinoma mouse model led to both reduction of tumor growth and increase in life expectancy of STM treated mice. Moreover, investigating the potential mechanism behind the favorable clinical outcomes, we provide evidence that STM stimulates a potent inflammatory response and a specific immune pattern, recruiting a large number of innate and adaptive immune cells capable to contrast the immunosuppressive environment generated by tumors.

HG-829 Is a Potent Noncompetitive Inhibitor of the ATP-Binding Cassette Multidrug Resistance Transporter ABCB1

PubMed Central

Caceres, Gisela; Robey, Robert W.; Sokol, Lubomir; McGraw, Kathy L.; Clark, Justine; Lawrence, Nicholas J.; Sebti, Said M.; Wiese, Michael; List, Alan F.

2015-01-01

Transmembrane drug export mediated by the ATP-binding cassette (ABC) transporter P-glycoprotein contributes to clinical resistance to antineoplastics. In this study, we identified the substituted quinoline HG-829 as a novel, noncompetitive, and potent P-glycoprotein inhibitor that overcomes in vitro and in vivo drug resistance. We found that nontoxic concentrations of HG-829 restored sensitivity to P-glycoprotein oncolytic substrates. In ABCB1-overexpressing cell lines, HG-829 significantly enhanced cytotoxicity to daunorubicin, paclitaxel, vinblastine, vincristine, and etoposide. Coadministration of HG-829 fully restored in vivo antitumor activity of daunorubicin in mice without added toxicity. Functional assays showed that HG-829 is not a Pgp substrate or competitive inhibitor of Pgp-mediated drug efflux but rather acts as a noncompetitive modulator of P-glycoprotein transport function. Taken together, our findings indicate that HG-829 is a potent, long-acting, and noncompetitive modulator of P-glycoprotein export function that may offer therapeutic promise for multidrugresistant malignancies. PMID:22761337

Cyclosporin A inhibits hepatitis B and hepatitis D virus entry by cyclophilin-independent interference with the NTCP receptor.

PubMed

Nkongolo, Shirin; Ni, Yi; Lempp, Florian A; Kaufman, Christina; Lindner, Thomas; Esser-Nobis, Katharina; Lohmann, Volker; Mier, Walter; Mehrle, Stefan; Urban, Stephan

2014-04-01

Chronic hepatitis B and hepatitis D are global health problems caused by the human hepatitis B and hepatitis D virus. The myristoylated preS1 domain of the large envelope protein mediates specific binding to hepatocytes by sodium taurocholate co-transporting polypeptide (NTCP). NTCP is a bile salt transporter known to be inhibited by cyclosporin A. This study aimed to characterize the effect of cyclosporin A on HBV/HDV infection. HepaRG cells, primary human hepatocytes, and susceptible NTCP-expressing hepatoma cell lines were applied for infection experiments. The mode of action of cyclosporin A was studied by comparing the effect of different inhibitors, cyclophilin A/B/C-silenced cell lines as well as NTCP variants and mutants. Bile salt transporter and HBV receptor functions were investigated by taurocholate uptake and quantification of HBVpreS binding. Cyclosporin A inhibited hepatitis B and D virus infections during and--less pronounced--prior to virus inoculation. Binding of HBVpreS to NTCP was blocked by cyclosporin A concentrations at 8 μM. An NTCP variant deficient in HBVpreS binding but competent for bile salt transport showed resistance to cyclosporin A. Silencing of cyclophilins A/B/C did not abrogate transporter and receptor inhibition. In contrast, tacrolimus, a cyclophilin-independent calcineurin inhibitor, was inactive. HBV and HDV entry via sodium taurocholate co-transporting polypeptide is inhibited by cyclosporin A. The interaction between the drug and the viral receptor is direct and overlaps with a functional binding site of the preS1 domain, which mediates viral entry. Copyright © 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

50 CFR 648.55 - Framework adjustments to management measures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... establish OFL, ABC, ACL, ACT, DAS allocations, rotational area management programs, percentage allocations... measures will be adjusted. (c) OFL, ABC, ACL, ACT, and AMs. The Council shall specify OFL, ABC, ACL, ACT... derive specifications for ABC, ACL, and ACT, as specified in paragraphs (c)(2) through (c)(5) of this...

50 CFR 648.55 - Framework adjustments to management measures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... establish OFL, ABC, ACL, ACT, DAS allocations, rotational area management programs, percentage allocations... measures will be adjusted. (c) OFL, ABC, ACL, ACT, and AMs. The Council shall specify OFL, ABC, ACL, ACT... derive specifications for ABC, ACL, and ACT, as specified in paragraphs (c)(2) through (c)(5) of this...

50 CFR 648.55 - Framework adjustments to management measures.

Code of Federal Regulations, 2012 CFR

2012-10-01

... establish OFL, ABC, ACL, ACT, DAS allocations, rotational area management programs, percentage allocations... measures will be adjusted. (c) OFL, ABC, ACL, ACT, and AMs. The Council shall specify OFL, ABC, ACL, ACT... derive specifications for ABC, ACL, and ACT, as specified in paragraphs (c)(2) through (c)(5) of this...

50 CFR 648.55 - Framework adjustments to management measures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... establish OFL, ABC, ACL, ACT, DAS allocations, rotational area management programs, percentage allocations... measures will be adjusted. (c) OFL, ABC, ACL, ACT, and AMs. The Council shall specify OFL, ABC, ACL, ACT... derive specifications for ABC, ACL, and ACT, as specified in paragraphs (a)(2) through (5) of this...

Export of extracellular polysaccharides modulates adherence of the Cyanobacterium synechocystis.

PubMed

Fisher, Michael L; Allen, Rebecca; Luo, Yingqin; Curtiss, Roy

2013-01-01

The field of cyanobacterial biofuel production is advancing rapidly, yet we know little of the basic biology of these organisms outside of their photosynthetic pathways. We aimed to gain a greater understanding of how the cyanobacterium Synechocystis PCC 6803 (Synechocystis, hereafter) modulates its cell surface. Such understanding will allow for the creation of mutants that autoflocculate in a regulated way, thus avoiding energy intensive centrifugation in the creation of biofuels. We constructed mutant strains lacking genes predicted to function in carbohydrate transport or synthesis. Strains with gene deletions of slr0977 (predicted to encode a permease component of an ABC transporter), slr0982 (predicted to encode an ATP binding component of an ABC transporter) and slr1610 (predicted to encode a methyltransferase) demonstrated flocculent phenotypes and increased adherence to glass. Upon bioinformatic inspection, the gene products of slr0977, slr0982, and slr1610 appear to function in O-antigen (OAg) transport and synthesis. However, the analysis provided here demonstrated no differences between OAg purified from wild-type and mutants. However, exopolysaccharides (EPS) purified from mutants were altered in composition when compared to wild-type. Our data suggest that there are multiple means to modulate the cell surface of Synechocystis by disrupting different combinations of ABC transporters and/or glycosyl transferases. Further understanding of these mechanisms may allow for the development of industrially and ecologically useful strains of cyanobacteria. Additionally, these data imply that many cyanobacterial gene products may possess as-yet undiscovered functions, and are meritorious of further study.

MsmK, an ATPase, Contributes to Utilization of Multiple Carbohydrates and Host Colonization of Streptococcus suis.

PubMed

Tan, Mei-Fang; Gao, Ting; Liu, Wan-Quan; Zhang, Chun-Yan; Yang, Xi; Zhu, Jia-Wen; Teng, Mu-Ye; Li, Lu; Zhou, Rui

2015-01-01

Acquisition and metabolism of carbohydrates are essential for host colonization and pathogenesis of bacterial pathogens. Different bacteria can uptake different lines of carbohydrates via ABC transporters, in which ATPase subunits energize the transport though ATP hydrolysis. Some ABC transporters possess their own ATPases, while some share a common ATPase. Here we identified MsmK, an ATPase from Streptococcus suis, an emerging zoonotic bacterium causing dead infections in pigs and humans. Genetic and biochemistry studies revealed that the MsmK was responsible for the utilization of raffinose, melibiose, maltotetraose, glycogen and maltotriose. In infected mice, the msmK-deletion mutant showed significant defects of survival and colonization when compared with its parental and complementary strains. Taken together, MsmK is an ATPase that contributes to multiple carbohydrates utilization and host colonization of S. suis. This study gives new insight into our understanding of the carbohydrates utilization and its relationship to the pathogenesis of this zoonotic pathogen.

Activity-based analyses lead to better decision making.

PubMed

Player, S

1998-08-01

Activity-based costing (ABC) and activity-based management (ABM) are cost-management tools that are relatively new to the healthcare industry. ABC is used for strategic decision making. It assesses the costs associated with specific activities and resources and links those costs to specific internal and external customers of the healthcare enterprise (e.g., patients, service lines, and physician groups) to determine the costs associated with each customer. This cost information then can be adjusted to account for anticipated changes and to predict future costs. ABM, on the other hand, supports operations by focusing on the causes of costs and how costs can be reduced. It assesses cost drivers that directly affect the cost of a product or service, and uses performance measures to evaluate the financial or nonfinancial benefit an activity provides. By identifying each cost driver and assessing the value the element adds to the healthcare enterprise, ABM provides a basis for selecting areas that can be changed to reduce costs.

MsmK, an ATPase, Contributes to Utilization of Multiple Carbohydrates and Host Colonization of Streptococcus suis

PubMed Central

Tan, Mei-Fang; Gao, Ting; Liu, Wan-Quan; Zhang, Chun-Yan; Yang, Xi; Zhu, Jia-Wen; Teng, Mu-Ye; Li, Lu; Zhou, Rui

2015-01-01

Acquisition and metabolism of carbohydrates are essential for host colonization and pathogenesis of bacterial pathogens. Different bacteria can uptake different lines of carbohydrates via ABC transporters, in which ATPase subunits energize the transport though ATP hydrolysis. Some ABC transporters possess their own ATPases, while some share a common ATPase. Here we identified MsmK, an ATPase from Streptococcus suis, an emerging zoonotic bacterium causing dead infections in pigs and humans. Genetic and biochemistry studies revealed that the MsmK was responsible for the utilization of raffinose, melibiose, maltotetraose, glycogen and maltotriose. In infected mice, the msmK-deletion mutant showed significant defects of survival and colonization when compared with its parental and complementary strains. Taken together, MsmK is an ATPase that contributes to multiple carbohydrates utilization and host colonization of S. suis. This study gives new insight into our understanding of the carbohydrates utilization and its relationship to the pathogenesis of this zoonotic pathogen. PMID:26222651

Increased expression of the yeast multidrug resistance ABC transporter Pdr18 leads to increased ethanol tolerance and ethanol production in high gravity alcoholic fermentation

PubMed Central

2012-01-01

Background The understanding of the molecular basis of yeast tolerance to ethanol may guide the design of rational strategies to increase process performance in industrial alcoholic fermentations. A set of 21 genes encoding multidrug transporters from the ATP-Binding Cassette (ABC) Superfamily and Major Facilitator Superfamily (MFS) in S. cerevisiae were scrutinized for a role in ethanol stress resistance. Results A yeast multidrug resistance ABC transporter encoded by the PDR18 gene, proposed to play a role in the incorporation of ergosterol in the yeast plasma membrane, was found to confer resistance to growth inhibitory concentrations of ethanol. PDR18 expression was seen to contribute to decreased 3 H-ethanol intracellular concentrations and decreased plasma membrane permeabilization of yeast cells challenged with inhibitory ethanol concentrations. Given the increased tolerance to ethanol of cells expressing PDR18, the final concentration of ethanol produced during high gravity alcoholic fermentation by yeast cells devoid of PDR18 was lower than the final ethanol concentration produced by the corresponding parental strain. Moreover, an engineered yeast strain in which the PDR18 promoter was replaced in the genome by the stronger PDR5 promoter, leading to increased PDR18 mRNA levels during alcoholic fermentation, was able to attain a 6 % higher ethanol concentration and a 17 % higher ethanol production yield than the parental strain. The improved fermentative performance of yeast cells over-expressing PDR18 was found to correlate with their increased ethanol tolerance and ability to restrain plasma membrane permeabilization induced throughout high gravity fermentation. Conclusions PDR18 gene over-expression increases yeast ethanol tolerance and fermentation performance leading to the production of highly inhibitory concentrations of ethanol. PDR18 overexpression in industrial yeast strains appears to be a promising approach to improve alcoholic fermentation performance for sustainable bio-ethanol production. PMID:22839110

Requirements for Information/Education Programs on Hypothermia.

DTIC Science & Technology

1979-10-23

NY (NBC) WEZF - Burlington, VT (ABC) Bangor, ME: 112,800 WLBZ - Bangor, ME (NBC) WABI - Bangor, ME (CBS) WVII - Bangor, ME (ABC) Presque Isle , ME...28,700 WAGM - Presque Isle , ME CBS(ABC-NBC) A-2 MID-ATLANTIC: 18,885,600 New York, NY: 6,375,500 Raleigh-Durham, NC: 451,800 WCBS - New York, NY (CBS...NY (ABC) WICZ - Binghamton, NY (NBC) WilingonNC: 135,300 WWAY -IWilmington, NC (ABC) WECT - Wilmington, NC NBC (CBS) Erie , PA: 132,600 WICU - Erie , PA

Building Self-Esteem of Children and Adolescents through Adventure-Based Counseling.

ERIC Educational Resources Information Center

Nassar-McMillan, Sylvia C.; Cashwell, Craig S.

1997-01-01

Explores ways in which communities and school counselors can foster self-esteem in children and adolescents through adventure-based counseling (ABC). Discusses the importance of self-esteem, the philosophy and tenets of ABC, the effectiveness of ABC, and ways to integrate ABC concepts into groups. Focuses on prevention and intervention. (RJM)

An Enhanced Artificial Bee Colony Algorithm with Solution Acceptance Rule and Probabilistic Multisearch.

PubMed

Yurtkuran, Alkın; Emel, Erdal

2016-01-01

The artificial bee colony (ABC) algorithm is a popular swarm based technique, which is inspired from the intelligent foraging behavior of honeybee swarms. This paper proposes a new variant of ABC algorithm, namely, enhanced ABC with solution acceptance rule and probabilistic multisearch (ABC-SA) to address global optimization problems. A new solution acceptance rule is proposed where, instead of greedy selection between old solution and new candidate solution, worse candidate solutions have a probability to be accepted. Additionally, the acceptance probability of worse candidates is nonlinearly decreased throughout the search process adaptively. Moreover, in order to improve the performance of the ABC and balance the intensification and diversification, a probabilistic multisearch strategy is presented. Three different search equations with distinctive characters are employed using predetermined search probabilities. By implementing a new solution acceptance rule and a probabilistic multisearch approach, the intensification and diversification performance of the ABC algorithm is improved. The proposed algorithm has been tested on well-known benchmark functions of varying dimensions by comparing against novel ABC variants, as well as several recent state-of-the-art algorithms. Computational results show that the proposed ABC-SA outperforms other ABC variants and is superior to state-of-the-art algorithms proposed in the literature.

A novel approach for dimension reduction of microarray.

PubMed

Aziz, Rabia; Verma, C K; Srivastava, Namita

2017-12-01

This paper proposes a new hybrid search technique for feature (gene) selection (FS) using Independent component analysis (ICA) and Artificial Bee Colony (ABC) called ICA+ABC, to select informative genes based on a Naïve Bayes (NB) algorithm. An important trait of this technique is the optimization of ICA feature vector using ABC. ICA+ABC is a hybrid search algorithm that combines the benefits of extraction approach, to reduce the size of data and wrapper approach, to optimize the reduced feature vectors. This hybrid search technique is facilitated by evaluating the performance of ICA+ABC on six standard gene expression datasets of classification. Extensive experiments were conducted to compare the performance of ICA+ABC with the results obtained from recently published Minimum Redundancy Maximum Relevance (mRMR) +ABC algorithm for NB classifier. Also to check the performance that how ICA+ABC works as feature selection with NB classifier, compared the combination of ICA with popular filter techniques and with other similar bio inspired algorithm such as Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). The result shows that ICA+ABC has a significant ability to generate small subsets of genes from the ICA feature vector, that significantly improve the classification accuracy of NB classifier compared to other previously suggested methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

Caenorhabditis elegans ABCRNAi transporters interact genetically with rde-2 and mut-7.

PubMed

Sundaram, Prema; Han, Wang; Cohen, Nancy; Echalier, Benjamin; Albin, John; Timmons, Lisa

2008-02-01

RNA interference (RNAi) mechanisms are conserved and consist of an interrelated network of activities that not only respond to exogenous dsRNA, but also perform endogenous functions required in the fine tuning of gene expression and in maintaining genome integrity. Not surprisingly, RNAi functions have widespread influences on cellular function and organismal development. Previously, we observed a reduced capacity to mount an RNAi response in nine Caenorhabditis elegans mutants that are defective in ABC transporter genes (ABC(RNAi) mutants). Here, we report an exhaustive study of mutants, collectively defective in 49 different ABC transporter genes, that allowed for the categorization of one additional transporter into the ABC(RNAi) gene class. Genetic complementation tests reveal functions for ABC(RNAi) transporters in the mut-7/rde-2 branch of the RNAi pathway. These second-site noncomplementation interactions suggest that ABC(RNAi) proteins and MUT-7/RDE-2 function together in parallel pathways and/or as multiprotein complexes. Like mut-7 and rde-2, some ABC(RNAi) mutants display transposon silencing defects. Finally, our analyses reveal a genetic interaction network of ABC(RNAi) gene function with respect to this part of the RNAi pathway. From our results, we speculate that the coordinated activities of ABC(RNAi) transporters, through their effects on endogenous RNAi-related mechanisms, ultimately affect chromosome function and integrity.

A novel artificial bee colony algorithm based on modified search equation and orthogonal learning.

PubMed

Gao, Wei-feng; Liu, San-yang; Huang, Ling-ling

2013-06-01

The artificial bee colony (ABC) algorithm is a relatively new optimization technique which has been shown to be competitive to other population-based algorithms. However, ABC has an insufficiency regarding its solution search equation, which is good at exploration but poor at exploitation. To address this concerning issue, we first propose an improved ABC method called as CABC where a modified search equation is applied to generate a candidate solution to improve the search ability of ABC. Furthermore, we use the orthogonal experimental design (OED) to form an orthogonal learning (OL) strategy for variant ABCs to discover more useful information from the search experiences. Owing to OED's good character of sampling a small number of well representative combinations for testing, the OL strategy can construct a more promising and efficient candidate solution. In this paper, the OL strategy is applied to three versions of ABC, i.e., the standard ABC, global-best-guided ABC (GABC), and CABC, which yields OABC, OGABC, and OCABC, respectively. The experimental results on a set of 22 benchmark functions demonstrate the effectiveness and efficiency of the modified search equation and the OL strategy. The comparisons with some other ABCs and several state-of-the-art algorithms show that the proposed algorithms significantly improve the performance of ABC. Moreover, OCABC offers the highest solution quality, fastest global convergence, and strongest robustness among all the contenders on almost all the test functions.

Application of activity-based costing (ABC) for a Peruvian NGO healthcare provider.

PubMed

Waters, H; Abdallah, H; Santillán, D

2001-01-01

This article describes the application of activity-based costing (ABC) to calculate the unit costs of the services for a health care provider in Peru. While traditional costing allocates overhead and indirect costs in proportion to production volume or to direct costs, ABC assigns costs through activities within an organization. ABC uses personnel interviews to determine principal activities and the distribution of individual's time among these activities. Indirect costs are linked to services through time allocation and other tracing methods, and the result is a more accurate estimate of unit costs. The study concludes that applying ABC in a developing country setting is feasible, yielding results that are directly applicable to pricing and management. ABC determines costs for individual clinics, departments and services according to the activities that originate these costs, showing where an organization spends its money. With this information, it is possible to identify services that are generating extra revenue and those operating at a loss, and to calculate cross subsidies across services. ABC also highlights areas in the health care process where efficiency improvements are possible. Conclusions about the ultimate impact of the methodology are not drawn here, since the study was not repeated and changes in utilization patterns and the addition of new clinics affected applicability of the results. A potential constraint to implementing ABC is the availability and organization of cost information. Applying ABC efficiently requires information to be readily available, by cost category and department, since the greatest benefits of ABC come from frequent, systematic application of the methodology in order to monitor efficiency and provide feedback for management. The article concludes with a discussion of the potential applications of ABC in the health sector in developing countries.

Virus spread and initial pathological changes in the nervous system in genital herpes simplex virus type 2 infection in mice. A correlative immunohistochemical, light and electron microscopic study.

PubMed

Georgsson, G; Martin, J R; Stoner, G L; Webster, H F

1987-01-01

Mice were infected by the vaginal route with the MS strain of herpes simplex virus type 2 (HSV-2). Serial vaginal cultures were used to confirm infection and to select mice for this study. Two mice were killed by perfusion on days 2-6 post infection (p.i.) and lumbar and sacral cord with cauda were fixed and embedded for electron microscopy. Semithin Epon-sections were stained for viral antigen using a rabbit anti-HSV-2 antiserum and the Avidin-Biotin (ABC) method. Thin sections from antigen-positive blocks were examined by electron microscopy, and the number and types of infected cells detected by these two methods were compared. A good correlation was found between detection of infected cells by these methods. Infected cells included neurons of dorsal root ganglia and spinal cord, satellite cells of dorsal root ganglia, non-myelinating Schwann cells, astrocytes, oligodendrocytes and arachnoidal cells. Infected cells were first detected in the cauda on day 3 p.i. and in the spinal cord on day 5 p.i. The temporal and spatial distribution of infected cells was consistent with neural spread to and within the CNS. The pathological lesions showed a good correlation with the distribution and number of infected cells and are probably due to a direct virus effect. The similar sensitivity of the Epon-ABC method to electron microscopy in detecting infected cells indicates that this method may have useful applications in both experimental and diagnostic work.

SU-E-T-401: Feasibility Study of Using ABC to Gate Lung SBRT Treatment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, D; Xie, X; Shepard, D

2014-06-01

Purpose: The current SBRT treatment techniques include free breathing (FB) SBRT and gated FB SBRT. Gated FB SBRT has smaller target and less lung toxicity with longer treatment time. The recent development of direct connectivity between the ABC and linac allowing for automated beam gating. In this study, we have examined the feasibility of using ABC system to gate the lung SBRT treatment. Methods: A CIRS lung phantom with a 3cm sphere-insert and a moving chest plate was used in this study. Sinusoidal motion was used for the FB pattern. An ABC signal was imported to simulate breath holds. 4D-CTmore » was taken in FB mode and average-intensity-projection (AIP) was used to create FB and 50% gated FB SBRT planning CT. A manually gated 3D CT scan was acquired for ABC gated SBRT planning.An SBRT plan was created for each treatment option. A surface-mapping system was used for 50% gating and ABC system was used for ABC gating. A manually gated CBCT scan was also performed to verify setup. Results: Among three options, the ABC gated plan has the smallest PTV of 35.94cc, which is 35% smaller comparing to that of the FB plan. Consequently, the V20 of the left lung reduced by 15% and 23% comparing to the 50% gated FB and FB plans, respectively. The FB plan took 4.7 minutes to deliver, while the 50% gated FB plan took 18.5 minutes. The ABC gated plan delivery took only 10.6 minutes. A stationary target with 3cm diameter was also obtained from the manually gated CBCT scan. Conclusion: A strategy for ABC gated lung SBRT was developed. ABC gating can significantly reduce the lung toxicity while maintaining the target coverage. Comparing to the 50% gated FB SBRT, ABC gated treatment can also provide less lung toxicity as well as improved delivery efficiency. This research is funded by Elekta.« less

ABC transporters are involved in defense against permethrin insecticide in the malaria vector Anopheles stephensi.

PubMed

Epis, Sara; Porretta, Daniele; Mastrantonio, Valentina; Comandatore, Francesco; Sassera, Davide; Rossi, Paolo; Cafarchia, Claudia; Otranto, Domenico; Favia, Guido; Genchi, Claudio; Bandi, Claudio; Urbanelli, Sandra

2014-07-29

Proteins from the ABC family (ATP-binding cassette) represent the largest known group of efflux pumps, responsible for transporting specific molecules across lipid membranes in both prokaryotic and eukaryotic organisms. In arthropods they have been shown to play a role in insecticide defense/resistance. The presence of ABC transporters and their possible association with insecticide transport have not yet been investigated in the mosquito Anopheles stephensi, the major vector of human malaria in the Middle East and South Asian regions. Here we investigated the presence and role of ABCs in transport of permethrin insecticide in a susceptible strain of this mosquito species. To identify ABC transporter genes we obtained a transcriptome from untreated larvae of An. stephensi and then compared it with the annotated transcriptome of Anopheles gambiae. To analyse the association between ABC transporters and permethrin we conducted bioassays with permethrin alone and in combination with an ABC inhibitor, and then we investigated expression profiles of the identified genes in larvae exposed to permethrin. Bioassays showed an increased mortality of mosquitoes when permethrin was used in combination with the ABC-transporter inhibitor. Genes for ABC transporters were detected in the transcriptome, and five were selected (AnstABCB2, AnstABCB3, AnstABCB4, AnstABCmember6 and AnstABCG4). An increased expression in one of them (AnstABCG4) was observed in larvae exposed to the LD50 dose of permethrin. Contrary to what was found in other insect species, no up-regulation was observed in the AnstABCB genes. Our results show for the first time the involvement of ABC transporters in larval defense against permethrin in An. stephensi and, more in general, confirm the role of ABC transporters in insecticide defense. The differences observed with previous studies highlight the need of further research as, despite the growing number of studies on ABC transporters in insects, the heterogeneity of the results available at present does not allow us to infer general trends in ABC transporter-insecticide interactions.

IFN-γ Stimulated Human Umbilical-Tissue-Derived Cells Potently Suppress NK Activation and Resist NK-Mediated Cytotoxicity In Vitro

PubMed Central

Noone, Cariosa; Kihm, Anthony; O'Dea, Shirley; Mahon, Bernard P.

2013-01-01

Umbilical cord tissue represents a unique source of cells with potential for cell therapy applications for multiple diseases. Human umbilical tissue-derived cells (hUTC) are a developmentally early stage, homogenous population of cells that are HLA-ABC dim, HLA-DR negative, and lack expression of co-stimulatory molecules in the unactivated state. The lack of HLA-DR and co-stimulatory molecule expression on unactivated hUTC may account for their reduced immunogenicity, facilitating their use in allogeneic settings. However, such approaches could be confounded by host innate cells such as natural killer (NK) cells. Here, we evaluate in vitro NK cell interactions with hUTC and compare them with human mesenchymal stem cells (MSC). Our investigations show that hUTC suppress NK activation, through prostaglandin-E2 secretion in a contact-independent manner. Prestimulation of hUTC or human MSC with interferon gamma (IFN-γ) induced expression of the tryptophan degrading enzyme indoleamine 2, 3 dioxygenase, facilitating enhanced suppression. However, resting NK cells of different killer immunoglobulin-like receptor haplotypes did not kill hUTC or MSC; only activated NK cells had the ability to kill nonstimulated hUTC and, to a lesser extent, MSC. The cell killing process involved signaling through the NKG2D receptor and the perforin/granzyme pathway; this was supported by CD54 (ICAM-1) expression by hUTC. IFN-γ-stimulated hUTC or hMSC were less susceptible to NK killing; in this case, protection was associated with elevated HLA-ABC expression. These data delineate the different mechanisms in a two-way interaction between NK cells and two distinct cell therapies, hUTC or hMSC, and how these interactions may influence their clinical applications. PMID:23795941

Chrysin and silibinin sensitize human glioblastoma cells for arsenic trioxide.

PubMed

Gülden, Michael; Appel, Daniel; Syska, Malin; Uecker, Stephanie; Wages, Franziska; Seibert, Hasso

2017-07-01

Arsenic trioxide (ATO) is highly efficient in treating acute promyelocytic leukemia. Other malignancies, however, are often less sensitive. Searching for compounds sensitizing arsenic resistant tumours for ATO the plant polyphenols, chrysin and silibinin, and the ATP binding cassette (ABC) transporter inhibitor MK-571, respectively, were investigated in human glioblastoma A-172 cells. The sensitivity of A-172 cells to ATO was characterized by a median cytotoxic concentration of 6 μM ATO. Subcytotoxic concentrations of chrysin, silibinin and MK-571, respectively, remarkably increased the sensitivity of the cells to ATO by factors of 4-6. Isobolographic analysis revealed synergistic interaction of the polyphenols and MK-571, respectively, with ATO. Sensitization by chrysin was associated with depletion of cellular glutathione and increased accumulation of arsenic. In contrast, silibinin and also MK-571 increased the accumulation of arsenic more strongly but without affecting the glutathione level. The increase of arsenic accumulation could be attributed to a decreased rate of arsenic export and, additionally, in the case of silibinin and MK-571, to an increasing amount of irreversibly accumulated arsenic. Direct interaction with ABC transporters stimulating export of glutathione and inhibiting export of arsenic, respectively, are discussed as likely mechanisms of the sensitizing activity of chrysin and silibinin. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantitative Proteomics Reveals Membrane Protein-Mediated Hypersaline Sensitivity and Adaptation in Halophilic Nocardiopsis xinjiangensis.

PubMed

Zhang, Yao; Li, Yanchang; Zhang, Yongguang; Wang, Zhiqiang; Zhao, Mingzhi; Su, Na; Zhang, Tao; Chen, Lingsheng; Wei, Wei; Luo, Jing; Zhou, Yanxia; Xu, Yongru; Xu, Ping; Li, Wenjun; Tao, Yong

2016-01-04

The genus Nocardiopsis is one of the most dominant Actinobacteria that survives in hypersaline environments. However, the adaptation mechanisms for halophilism are still unclear. Here, we performed isobaric tags for relative and absolute quantification based quantitative proteomics to investigate the functions of the membrane proteome after salt stress. A total of 683 membrane proteins were identified and quantified, of which 126 membrane proteins displayed salt-induced changes in abundance. Intriguingly, bioinformatics analyses indicated that these differential proteins showed two expression patterns, which were further validated by phenotypic changes and functional differences. The majority of ABC transporters, secondary active transporters, cell motility proteins, and signal transduction kinases were up-regulated with increasing salt concentration, whereas cell differentiation, small molecular transporter (ions and amino acids), and secondary metabolism proteins were significantly up-regulated at optimum salinity, but down-regulated or unchanged at higher salinity. The small molecule transporters and cell differentiation-related proteins acted as sensing proteins that played a more important biological role at optimum salinity. However, the ABC transporters for compatible solutes, Na(+)-dependent transporters, and cell motility proteins acted as adaptive proteins that actively counteracted higher salinity stress. Overall, regulation of membrane proteins may provide a major protection strategy against hyperosmotic stress.

LXR agonist treatment of blastic plasmacytoid dendritic cell neoplasm restores cholesterol efflux and triggers apoptosis.

PubMed

Ceroi, Adam; Masson, David; Roggy, Anne; Roumier, Christophe; Chagué, Cécile; Gauthier, Thierry; Philippe, Laure; Lamarthée, Baptiste; Angelot-Delettre, Fanny; Bonnefoy, Francis; Perruche, Sylvain; Biichle, Sabeha; Preudhomme, Claude; Macintyre, Elisabeth; Lagrost, Laurent; Garnache-Ottou, Francine; Saas, Philippe

2016-12-08

Blastic plasmacytoid dendritic cell (PDC) neoplasm (BPDCN) is an aggressive hematological malignancy with a poor prognosis that derives from PDCs. No consensus for optimal treatment modalities is available today and the full characterization of this leukemia is still emerging. We identified here a BPDCN-specific transcriptomic profile when compared with those of acute myeloid leukemia and T-acute lymphoblastic leukemia, as well as the transcriptomic signature of primary PDCs. This BPDCN gene signature identified a dysregulation of genes involved in cholesterol homeostasis, some of them being liver X receptor (LXR) target genes. LXR agonist treatment of primary BPDCN cells and BPDCN cell lines restored LXR target gene expression and increased cholesterol efflux via the upregulation of adenosine triphosphate-binding cassette (ABC) transporters, ABCA1 and ABCG1. LXR agonist treatment was responsible for limiting BPDCN cell proliferation and inducing intrinsic apoptotic cell death. LXR activation in BPDCN cells was shown to interfere with 3 signaling pathways associated with leukemic cell survival, namely: NF-κB activation, as well as Akt and STAT5 phosphorylation in response to the BPDCN growth/survival factor interleukin-3. These effects were increased by the stimulation of cholesterol efflux through a lipid acceptor, the apolipoprotein A1. In vivo experiments using a mouse model of BPDCN cell xenograft revealed a decrease of leukemic cell infiltration and BPDCN-induced cytopenia associated with increased survival after LXR agonist treatment. This demonstrates that cholesterol homeostasis is modified in BPDCN and can be normalized by treatment with LXR agonists which can be proposed as a new therapeutic approach. © 2016 by The American Society of Hematology.

Anti-tumor efficacy study of the Bruton's tyrosine kinase (BTK) inhibitor, ONO/GS-4059, in combination with the glycoengineered type II anti-CD20 monoclonal antibody obinutuzumab (GA101) demonstrates superior in vivo efficacy compared to ONO/GS-4059 in combination with rituximab.

PubMed

Yasuhiro, Tomoko; Sawada, Wako; Klein, Christian; Kozaki, Ryohei; Hotta, Shingo; Yoshizawa, Toshio

2017-03-01

The activated B-cell diffuse large B-cell-like lymphoma (ABC-DLBCL) correlates with poor prognosis. The B-cell receptor signaling pathway is known to be dysregulated in NHL/CLL and given BTK is a downstream mediator of BCR signaling, BTK constitutes an interesting and obvious therapeutic target. Given the high potency and selectivity of the BTK inhibitor, ONO/GS-4059, it was hypothesized that, the anti-tumor activity of ONO/GS-4059 could be further enhanced by combining it with the anti-CD20 Abs, rituximab (RTX) or obinutuzumab (GA101). ONO/GS-4059 combined with GA101 or RTX was significantly better than the respective monotherapy with tumor growth inhibition (TGI) of 90% for the GA101 combination and 86% for the RTX combination. In contrast, ibrutinib (PCI-32765) combined with RTX did not result in improved efficacy compared with respective monotherapy. Taken together these data indicate that the combination of ONO/GS-4059 with rituximab and particularly obinutuzumab may be an effective treatment for ABC-DLBCL.

Expression Profile of Drug and Nutrient Absorption Related Genes in Madin-Darby Canine Kidney (MDCK) Cells Grown under Differentiation Conditions.

PubMed

Quan, Yong; Jin, Yisheng; Faria, Teresa N; Tilford, Charles A; He, Aiqing; Wall, Doris A; Smith, Ronald L; Vig, Balvinder S

2012-06-18

The expression levels of genes involved in drug and nutrient absorption were evaluated in the Madin-Darby Canine Kidney (MDCK) in vitro drug absorption model. MDCK cells were grown on plastic surfaces (for 3 days) or on Transwell® membranes (for 3, 5, 7, and 9 days). The expression profile of genes including ABC transporters, SLC transporters, and cytochrome P450 (CYP) enzymes was determined using the Affymetrix® Canine GeneChip®. Expression of genes whose probe sets passed a stringent confirmation process was examined. Expression of a few transporter (MDR1, PEPT1 and PEPT2) genes in MDCK cells was confirmed by RT-PCR. The overall gene expression profile was strongly influenced by the type of support the cells were grown on. After 3 days of growth, expression of 28% of the genes was statistically different (1.5-fold cutoff, p < 0.05) between the cells grown on plastic and Transwell® membranes. When cells were differentiated on Transwell® membranes, large changes in gene expression profile were observed during the early stages, which then stabilized after 5-7 days. Only a small number of genes encoding drug absorption related SLC, ABC, and CYP were detected in MDCK cells, and most of them exhibited low hybridization signals. Results from this study provide valuable reference information on endogenous gene expression in MDCK cells that could assist in design of drug-transporter and/or drug-enzyme interaction studies, and help interpret the contributions of various transporters and metabolic enzymes in studies with MDCK cells.

Expression Profile of Drug and Nutrient Absorption Related Genes in Madin-Darby Canine Kidney (MDCK) Cells Grown under Differentiation Conditions

PubMed Central

Quan, Yong; Jin, Yisheng; Faria, Teresa N.; Tilford, Charles A.; He, Aiqing; Wall, Doris A.; Smith, Ronald L.; Vig, Balvinder S.

2012-01-01

The expression levels of genes involved in drug and nutrient absorption were evaluated in the Madin-Darby Canine Kidney (MDCK) in vitro drug absorption model. MDCK cells were grown on plastic surfaces (for 3 days) or on Transwell® membranes (for 3, 5, 7, and 9 days). The expression profile of genes including ABC transporters, SLC transporters, and cytochrome P450 (CYP) enzymes was determined using the Affymetrix® Canine GeneChip®. Expression of genes whose probe sets passed a stringent confirmation process was examined. Expression of a few transporter (MDR1, PEPT1 and PEPT2) genes in MDCK cells was confirmed by RT-PCR. The overall gene expression profile was strongly influenced by the type of support the cells were grown on. After 3 days of growth, expression of 28% of the genes was statistically different (1.5-fold cutoff, p < 0.05) between the cells grown on plastic and Transwell® membranes. When cells were differentiated on Transwell® membranes, large changes in gene expression profile were observed during the early stages, which then stabilized after 5–7 days. Only a small number of genes encoding drug absorption related SLC, ABC, and CYP were detected in MDCK cells, and most of them exhibited low hybridization signals. Results from this study provide valuable reference information on endogenous gene expression in MDCK cells that could assist in design of drug-transporter and/or drug-enzyme interaction studies, and help interpret the contributions of various transporters and metabolic enzymes in studies with MDCK cells. PMID:24300234

Application of fluorescent dye substrates for functional characterization of ABC multidrug transporters at a single cell level.

PubMed

Nerada, Zsuzsanna; Hegyi, Zoltán; Szepesi, Áron; Tóth, Szilárd; Hegedüs, Csilla; Várady, György; Matula, Zsolt; Homolya, László; Sarkadi, Balázs; Telbisz, Ágnes

2016-09-01

ABC multidrug transporters are key players in cancer multidrug resistance and in determining the ADME-Tox properties of drugs and xenobiotics. The most sensitive and specific detection of these transporters is based on functional assays. Assessment of the transporter-dependent reduction of cellular uptake of the fluorescent dyes, such as Hoechst 33342 (Ho) and more recently DyeCycle Violet (DCV), have been widely advocated for the characterization of both ABCB1 and ABCG2 multidrug transporters. Detailed comparison of these supravital DNA-binding dyes revealed that DCV is less toxic to ABCG2- and ABCB1-expressing cells than Ho. ATPase measurements imply that DCV and Ho are similarly handled by ABCB1, whereas ABCG2 seems to transport DVC more effectively. In addition, we have developed an image-based high content microscopy screening method for simultaneous in situ measurement of the cellular activity and expression of the ABCG2 multidrug transporter. We demonstrated the applicability of this method for identifying ABCG2-positive cells in heterogeneous cell population by a single dye uptake measurement. These results may promote multidrug transporter studies at a single cell level and allow the quantitative detection of clinically important drug-resistant sub-populations. © 2016 International Society for Advancement of Cytometry. © 2016 International Society for Advancement of Cytometry.

Using a Time-Driven Activity-Based Costing Model To Determine the Actual Cost of Services Provided by a Transgenic Core.

PubMed

Gerwin, Philip M; Norinsky, Rada M; Tolwani, Ravi J

2018-03-01

Laboratory animal programs and core laboratories often set service rates based on cost estimates. However, actual costs may be unknown, and service rates may not reflect the actual cost of services. Accurately evaluating the actual costs of services can be challenging and time-consuming. We used a time-driven activity-based costing (ABC) model to determine the cost of services provided by a resource laboratory at our institution. The time-driven approach is a more efficient approach to calculating costs than using a traditional ABC model. We calculated only 2 parameters: the time required to perform an activity and the unit cost of the activity based on employee cost. This method allowed us to rapidly and accurately calculate the actual cost of services provided, including microinjection of a DNA construct, microinjection of embryonic stem cells, embryo transfer, and in vitro fertilization. We successfully implemented a time-driven ABC model to evaluate the cost of these services and the capacity of labor used to deliver them. We determined how actual costs compared with current service rates. In addition, we determined that the labor supplied to conduct all services (10,645 min/wk) exceeded the practical labor capacity (8400 min/wk), indicating that the laboratory team was highly efficient and that additional labor capacity was needed to prevent overloading of the current team. Importantly, this time-driven ABC approach allowed us to establish a baseline model that can easily be updated to reflect operational changes or changes in labor costs. We demonstrated that a time-driven ABC model is a powerful management tool that can be applied to other core facilities as well as to entire animal programs, providing valuable information that can be used to set rates based on the actual cost of services and to improve operating efficiency.

Paenalcaligenes suwonensis sp. nov., isolated from spent mushroom compost.

PubMed

Moon, Ji-Young; Lim, Jun-Muk; Ahn, Jae-Hyung; Weon, Hang-Yeon; Kwon, Soon-Wo; Kim, Soo-Jin

2014-03-01

A bacterial strain, ABC02-12(T), was isolated from spent mushroom compost, a waste product of button mushroom cultivation. Cells of the strain were Gram-stain-negative, catalase- and oxidase-positive, non-spore-forming, aerobic flagellated rods. Optimum growth occurred at 28 °C and pH 7.0. 16S rRNA gene sequence analysis showed that strain ABC02-12(T) shared the highest sequence similarities with Paenalcaligenes hominis CCUG 53761A(T) (96.0 %), Alcaligenes faecalis subsp. parafaecalis G(T) (95.7 %), Alcaligenes faecalis subsp. faecalis IAM 12369(T) (95.4 %) and Pusillimonas noertemannii BN9(T) (95.3 %). According to the phylogenetic tree, strain ABC02-12(T) formed a robust cluster with Paenalcaligenes hominis CCUG 53761A(T) and Paenalcaligenes hermetiae KBL009(T). The quinone system was ubiquinone Q-8 with minor amounts of Q-7. The major fatty acids (>5 % of total fatty acids) were C16 : 0, C16 : 1ω6c and/or C16 : 1ω7c (summed feature 3), C18 : 1ω7c and/or C18 : 1ω6c (summed feature 8), C17 : 0 cyclo, and iso-C16 : 1 I, C14 : 0 3-OH and/or an unknown fatty acid (summed feature 2). The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and an unknown aminolipid. Putrescine was the principal polyamine, with small amounts of 2-hydroxyputrescine and cadaverine. On the basis of the evidence presented in this study, strain ABC02-12(T) is a representative of a novel species within the genus Paenalcaligenes, for which the name Paenalcaligenes suwonensis sp. nov. is proposed. The type strain is ABC02-12(T) ( = KACC 16537(T) = NBRC 108927(T)).

Volume Quantification of Acute Infratentorial Hemorrhage with Computed Tomography: Validation of the Formula 1/2ABC and 2/3SH

PubMed Central

Zhang, Yunyun; Yan, Jing; Fu, Yi; Chen, Shengdi

2013-01-01

Objective To compare the accuracy of formula 1/2ABC with 2/3SH on volume estimation for hypertensive infratentorial hematoma. Methods One hundred and forty-seven CT scans diagnosed as hypertensive infratentorial hemorrhage were reviewed. Based on the shape, hematomas were categorized as regular or irregular. Multilobular was defined as a special shape of irregular. Hematoma volume was calculated employing computer-assisted volumetric analysis (CAVA), 1/2ABC and 2/3SH, respectively. Results The correlation coefficients between 1/2ABC (or 2/3SH) and CAVA were greater than 0.900 in all subgroups. There were neither significant differences in absolute values of volume deviation nor percentage deviation between 1/2ABC and 2/3SH for regular hemorrhage (P>0.05). While for cerebellar, brainstem and irregular hemorrhages, the absolute values of volume deviation and percentage deviation by formula 1/2ABC were greater than 2/3SH (P<0.05). 1/2ABC and 2/3SH underestimated hematoma volume each by 10% and 5% for cerebellar hemorrhage, 14% and 9% for brainstem hemorrhage, 19% and 16% for regular hemorrhage, 9% and 3% for irregular hemorrhage, respectively. In addition, for the multilobular hemorrhage, 1/2ABC underestimated the volume by 9% while 2/3SH overestimated it by 2%. Conclusions For regular hemorrhage volume calculation, the accuracy of 2/3SH is similar to 1/2ABC. While for cerebellar, brainstem or irregular hemorrhages (including multilobular), 2/3SH is more accurate than 1/2ABC. PMID:23638025

ABC versus CAB for cardiopulmonary resuscitation: a prospective, randomized simulator-based trial.

PubMed

Marsch, Stephan; Tschan, Franziska; Semmer, Norbert K; Zobrist, Roger; Hunziker, Patrick R; Hunziker, Sabina

2013-09-06

After years of advocating ABC (Airway-Breathing-Circulation), current guidelines of cardiopulmonary resuscitation (CPR) recommend CAB (Circulation-Airway-Breathing). This trial compared ABC with CAB as initial approach to CPR from the arrival of rescuers until the completion of the first resuscitation cycle. 108 teams, consisting of two physicians each, were randomized to receive a graphical display of either the ABC algorithm or the CAB algorithm. Subsequently teams had to treat a simulated cardiac arrest. Data analysis was performed using video recordings obtained during simulations. The primary endpoint was the time to completion of the first resuscitation cycle of 30 compressions and two ventilations. The time to execution of the first resuscitation measure was 32 ± 12 seconds in ABC teams and 25 ± 10 seconds in CAB teams (P = 0.002). 18/53 ABC teams (34%) and none of the 55 CAB teams (P = 0.006) applied more than the recommended two initial rescue breaths which caused a longer duration of the first cycle of 30 compressions and two ventilations in ABC teams (31 ± 13 vs.23 ± 6 sec; P = 0.001). Overall, the time to completion of the first resuscitation cycle was longer in ABC teams (63 ± 17 vs. 48 ± 10 sec; P <0.0001). This randomized controlled trial found CAB superior to ABC with an earlier start of CPR and a shorter time to completion of the first 30:2 resuscitation cycle. These findings endorse the change from ABC to CAB in international resuscitation guidelines.

Anticipated Benefits of Care (ABC): psychometrics and predictive value in psychiatric disorders.

PubMed

Warden, D; Trivedi, M H; Carmody, T J; Gollan, J K; Kashner, T M; Lind, L; Crismon, M L; Rush, A J

2010-06-01

Attitudes and expectations about treatment have been associated with symptomatic outcomes, adherence and utilization in patients with psychiatric disorders. No measure of patients' anticipated benefits of treatment on domains of everyday functioning has previously been available. The Anticipated Benefits of Care (ABC) is a new, 10-item questionnaire used to measure patient expectations about the impact of treatment on domains of everyday functioning. The ABC was collected at baseline in adult out-patients with major depressive disorder (MDD) (n=528), bipolar disorder (n=395) and schizophrenia (n=447) in the Texas Medication Algorithm Project (TMAP). Psychometric properties of the ABC were assessed, and the association of ABC scores with treatment response at 3 months was evaluated. Evaluation of the ABC's internal consistency yielded Cronbach's alpha of 0.90-0.92 for patients across disorders. Factor analysis showed that the ABC was unidimensional for all patients and for patients with each disorder. For patients with MDD, lower anticipated benefits of treatment was associated with less symptom improvement and lower odds of treatment response [odds ratio (OR) 0.72, 95% confidence interval (CI) 0.57-0.87, p=0.0011]. There was no association between ABC and symptom improvement or treatment response for patients with bipolar disorder or schizophrenia, possibly because these patients had modest benefits with treatment. The ABC is the first self-report that measures patient expectations about the benefits of treatment on everyday functioning, filling an important gap in available assessments of attitudes and expectations about treatment. The ABC is simple, easy to use, and has acceptable psychometric properties for use in research or clinical settings.

77 FR 6569 - National Institute of Environmental Health Sciences; Notice of Closed Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-08

... Health Sciences, Special Emphasis Panel, Environmental Stem Cells Research. Date: February 29-March 2..., 150 Park Drive, Ballroom ABC, Research Triangle Park, NC 27709. Contact Person: Teresa Nesbitt, Ph.D., DVM, Chief, Scientific Review Branch, Division of Extramural Research and Training, National Institute...

The Role of ABC Proteins in Drug-Resistant Breast Cancer Cells

DTIC Science & Technology

2007-04-01

and a biotin acceptor domain) under control of the alcohol oxidase promoter (Figure 2). Upon methanol induction, the yeast expressed high levels of...as native cDNA. Therefore, we backtranslated the protein into a nucleotide sequence codon-optimized for expression in Pichia pastoris yeast. Yeast

CRTP-13: ABC-GCB Expression Signatures in Human B-cell Lymphoma on the NanoString Platform | Frederick National Laboratory for Cancer Research

Cancer.gov

The CLIA Molecular Diagnostics Laboratory within the Cancer Research Technology Program will perform messenger RNA isolation and expression analysis specific to a 20-gene panel on formalin-fixed paraffin-embedded (FFPE) patient samples using the Nano

mRMR-ABC: A Hybrid Gene Selection Algorithm for Cancer Classification Using Microarray Gene Expression Profiling

PubMed Central

Alshamlan, Hala; Badr, Ghada; Alohali, Yousef

2015-01-01

An artificial bee colony (ABC) is a relatively recent swarm intelligence optimization approach. In this paper, we propose the first attempt at applying ABC algorithm in analyzing a microarray gene expression profile. In addition, we propose an innovative feature selection algorithm, minimum redundancy maximum relevance (mRMR), and combine it with an ABC algorithm, mRMR-ABC, to select informative genes from microarray profile. The new approach is based on a support vector machine (SVM) algorithm to measure the classification accuracy for selected genes. We evaluate the performance of the proposed mRMR-ABC algorithm by conducting extensive experiments on six binary and multiclass gene expression microarray datasets. Furthermore, we compare our proposed mRMR-ABC algorithm with previously known techniques. We reimplemented two of these techniques for the sake of a fair comparison using the same parameters. These two techniques are mRMR when combined with a genetic algorithm (mRMR-GA) and mRMR when combined with a particle swarm optimization algorithm (mRMR-PSO). The experimental results prove that the proposed mRMR-ABC algorithm achieves accurate classification performance using small number of predictive genes when tested using both datasets and compared to previously suggested methods. This shows that mRMR-ABC is a promising approach for solving gene selection and cancer classification problems. PMID:25961028

mRMR-ABC: A Hybrid Gene Selection Algorithm for Cancer Classification Using Microarray Gene Expression Profiling.

PubMed

Alshamlan, Hala; Badr, Ghada; Alohali, Yousef

2015-01-01

An artificial bee colony (ABC) is a relatively recent swarm intelligence optimization approach. In this paper, we propose the first attempt at applying ABC algorithm in analyzing a microarray gene expression profile. In addition, we propose an innovative feature selection algorithm, minimum redundancy maximum relevance (mRMR), and combine it with an ABC algorithm, mRMR-ABC, to select informative genes from microarray profile. The new approach is based on a support vector machine (SVM) algorithm to measure the classification accuracy for selected genes. We evaluate the performance of the proposed mRMR-ABC algorithm by conducting extensive experiments on six binary and multiclass gene expression microarray datasets. Furthermore, we compare our proposed mRMR-ABC algorithm with previously known techniques. We reimplemented two of these techniques for the sake of a fair comparison using the same parameters. These two techniques are mRMR when combined with a genetic algorithm (mRMR-GA) and mRMR when combined with a particle swarm optimization algorithm (mRMR-PSO). The experimental results prove that the proposed mRMR-ABC algorithm achieves accurate classification performance using small number of predictive genes when tested using both datasets and compared to previously suggested methods. This shows that mRMR-ABC is a promising approach for solving gene selection and cancer classification problems.

Linear and nonlinear dynamo properties of time-dependent ABC flows

NASA Astrophysics Data System (ADS)

Brummell, N. H.; Cattaneo, F.; Tobias, S. M.

2001-04-01

The linear and nonlinear dynamo properties of a class of periodically forced flows is considered. The forcing functions are chosen to drive, in the absence of magnetic effects (kinematic regime), a time-dependent version of the ABC flow with A= B= C=1. The time-dependence consists of a harmonic displacement of the origin along the line x= y= z=1 with amplitude ɛ and frequency Ω. The finite-time Lyapunov exponents are computed for several values of ɛ and Ω. It is found that for values of these parameters near unity chaotic streamlines occupy most of the volume. In this parameter range, and for moderate kinetic and magnetic Reynolds numbers, the basic flow is both hydrodynamically and hydromagnetically unstable. However, the dynamo instability has a higher growth rate than the hydrodynamic one, so that the nonlinear regime can be reached with negligible departures from the basic ABC flow. In the nonlinear regime, two distinct classes of behaviour are observed. In one, the exponential growth of the magnetic field saturates and the dynamo settles to a stationary state whereby the magnetic energy is maintained indefinitely. In the other the velocity field evolves to a nondynamo state and the magnetic field, following an initial amplification, decays to zero. The transition from the dynamo to the nondynamo state can be mediated by the hydrodynamic instability or by magnetic perturbations. The properties of the ensuing nonlinear dynamo states are investigated for different parameter values. The implications for a general theory of nonlinear dynamos are discussed.

Barley has two peroxisomal ABC transporters with multiple functions in β-oxidation

PubMed Central

Mendiondo, Guillermina M.; Medhurst, Anne; van Roermund, Carlo W.; Zhang, Xuebin; Devonshire, Jean; Scholefield, Duncan; Fernández, José; Axcell, Barry; Ramsay, Luke; Waterham, Hans R.; Waugh, Robbie; Theodoulou, Frederica L.; Holdsworth, Michael J.

2014-01-01

In oilseed plants, peroxisomal β-oxidation functions not only in lipid catabolism but also in jasmonate biosynthesis and metabolism of pro-auxins. Subfamily D ATP-binding cassette (ABC) transporters mediate import of β-oxidation substrates into the peroxisome, and the Arabidopsis ABCD protein, COMATOSE (CTS), is essential for this function. Here, the roles of peroxisomal ABCD transporters were investigated in barley, where the main storage compound is starch. Barley has two CTS homologues, designated HvABCD1 and HvABCD2, which are widely expressed and present in embryo and aleurone tissues during germination. Suppression of both genes in barley RNA interference (RNAi) lines indicated roles in metabolism of 2,4-dichlorophenoxybutyrate (2,4-DB) and indole butyric acid (IBA), jasmonate biosynthesis, and determination of grain size. Transformation of the Arabidopsis cts-1 null mutant with HvABCD1 and HvABCD2 confirmed these findings. HvABCD2 partially or completely complemented all tested phenotypes of cts-1. In contrast, HvABCD1 failed to complement the germination and establishment phenotypes of cts-1 but increased the sensitivity of hypocotyls to 100 μM IBA and partially complemented the seed size phenotype. HvABCD1 also partially complemented the yeast pxa1/pxa2Δ mutant for fatty acid β-oxidation. It is concluded that the core biochemical functions of peroxisomal ABC transporters are largely conserved between oilseeds and cereals but that their physiological roles and importance may differ. PMID:24913629

Parameter Estimation for a Pulsating Turbulent Buoyant Jet Using Approximate Bayesian Computation

NASA Astrophysics Data System (ADS)

Christopher, Jason; Wimer, Nicholas; Lapointe, Caelan; Hayden, Torrey; Grooms, Ian; Rieker, Greg; Hamlington, Peter

2017-11-01

Approximate Bayesian Computation (ABC) is a powerful tool that allows sparse experimental or other ``truth'' data to be used for the prediction of unknown parameters, such as flow properties and boundary conditions, in numerical simulations of real-world engineering systems. Here we introduce the ABC approach and then use ABC to predict unknown inflow conditions in simulations of a two-dimensional (2D) turbulent, high-temperature buoyant jet. For this test case, truth data are obtained from a direct numerical simulation (DNS) with known boundary conditions and problem parameters, while the ABC procedure utilizes lower fidelity large eddy simulations. Using spatially-sparse statistics from the 2D buoyant jet DNS, we show that the ABC method provides accurate predictions of true jet inflow parameters. The success of the ABC approach in the present test suggests that ABC is a useful and versatile tool for predicting flow information, such as boundary conditions, that can be difficult to determine experimentally.

First MRI application of an active breathing coordinator

NASA Astrophysics Data System (ADS)

Kaza, E.; Symonds-Tayler, R.; Collins, D. J.; McDonald, F.; McNair, H. A.; Scurr, E.; Koh, D.-M.; Leach, M. O.

2015-02-01

A commercial active breathing coordinator (ABC) device, employed to hold respiration at a specific level for a predefined duration, was successfully adapted for magnetic resonance imaging (MRI) use for the first time. Potential effects of the necessary modifications were assessed and taken into account. Automatic MR acquisition during ABC breath holding was achieved. The feasibility of MR-ABC thoracic and abdominal examinations together with the advantages of imaging in repeated ABC-controlled breath holds were demonstrated on healthy volunteers. Five lung cancer patients were imaged under MR-ABC, visually confirming the very good intra-session reproducibility of organ position in images acquired with the same patient positioning as used for computed tomography (CT). Using identical ABC settings, good MR-CT inter-modality registration was achieved. This demonstrates the value of ABC, since application of T1, T2 and diffusion weighted MR sequences provides a wider range of contrast mechanisms and additional diagnostic information compared to CT, thus improving radiotherapy treatment planning and assessment.

First MRI application of an active breathing coordinator.

PubMed

Kaza, E; Symonds-Tayler, R; Collins, D J; McDonald, F; McNair, H A; Scurr, E; Koh, D-M; Leach, M O

2015-02-21

A commercial active breathing coordinator (ABC) device, employed to hold respiration at a specific level for a predefined duration, was successfully adapted for magnetic resonance imaging (MRI) use for the first time. Potential effects of the necessary modifications were assessed and taken into account. Automatic MR acquisition during ABC breath holding was achieved. The feasibility of MR-ABC thoracic and abdominal examinations together with the advantages of imaging in repeated ABC-controlled breath holds were demonstrated on healthy volunteers. Five lung cancer patients were imaged under MR-ABC, visually confirming the very good intra-session reproducibility of organ position in images acquired with the same patient positioning as used for computed tomography (CT). Using identical ABC settings, good MR-CT inter-modality registration was achieved. This demonstrates the value of ABC, since application of T1, T2 and diffusion weighted MR sequences provides a wider range of contrast mechanisms and additional diagnostic information compared to CT, thus improving radiotherapy treatment planning and assessment.

First MRI application of an active breathing coordinator

PubMed Central

Kaza, E; Symonds-Tayler, R; Collins, D J; McDonald, F; McNair, H A; Scurr, E; Koh, D-M; Leach, M O

2015-01-01

Abstract A commercial active breathing coordinator (ABC) device, employed to hold respiration at a specific level for a predefined duration, was successfully adapted for magnetic resonance imaging (MRI) use for the first time. Potential effects of the necessary modifications were assessed and taken into account. Automatic MR acquisition during ABC breath holding was achieved. The feasibility of MR-ABC thoracic and abdominal examinations together with the advantages of imaging in repeated ABC-controlled breath holds were demonstrated on healthy volunteers. Five lung cancer patients were imaged under MR-ABC, visually confirming the very good intra-session reproducibility of organ position in images acquired with the same patient positioning as used for computed tomography (CT). Using identical ABC settings, good MR-CT inter-modality registration was achieved. This demonstrates the value of ABC, since application of T1, T2 and diffusion weighted MR sequences provides a wider range of contrast mechanisms and additional diagnostic information compared to CT, thus improving radiotherapy treatment planning and assessment. PMID:25633183

Effects of a Shuangling Fuzheng anticancer preparation on the proliferation of SGC-7901 cells and immune function in a cyclophosphamide-treated murine model.

PubMed

Chen, Hua-Sheng; Chen, Jue; Cui, De-Li; Zheng, Yuan-Yuan; Xu, Ai-Hua; Chen, Gang; Jia, Ling-Chang

2007-12-28

To study the inhibitory effects of a Shuangling Fuzheng anticancer preparation (SFAP) on the human gastric cancer cell line SGC-7901 in vitro as well as its immune-modulated effects in a cyclophosphamide-treated murine model. MTT experiments and immunocytochemistry ABC experiments were performed for detecting the proliferation of SGC-7901 cells in vitro and protein expression of c-myc. The staphylococcal protein A (SPA) rosette test was utilized for measuring the ratio of T-lymphocyte subsets from peripheral blood in a cyclophosphamide-treated murine model. Enzyme-linked immunosorbant assay (ELISA) was performed for measuring the levels of serum sIL-2R in treated mice, while immunoturbidimetry was used for measuring the levels of immunoglobulins (Ig). SFAP (40-640 mg/L, 48 h) inhibited the proliferation of SGC-7901 cells, and a positive correlation was noted between inhibitory effects and dosage. At a dosage of 160-320 mg/L in cultured cells, the expression of c-myc was decreased. SFAP (50-200 mg/kg) increased the percentage of CD3+ and CD4+ T-lymphocytes, the ratio of CD4/CD8, and the contents of Ig such as IgM, IgG or IgA, but decreased the levels of serum sIL-2R in peripheral blood from cyclophosphamide-treated mice. SFAP can inhibit the proliferation of SGC-7901 cells via the c-myc gene. In addition, SFAP can modulat the cellular and humoral immunity in cyclophosphamide-induced immunosuppressed mice.

A Study of the Communication Capabilities of the OPARS Flight Planning System for Various Levels of Demand.

DTIC Science & Technology

1980-03-01

Oceanography Center (FNOC) is currently testing and evaluating a computerized flight plan system, referred to, for short, as OPARS. This sytem , developed to...replace the Lockheed Jetplan flight plan sytem , provides users at remote sites with direct access to the FNOC computer via 11 telephone lines. The...validity, but only for format. For example, an entry of ABCE , as the four- letter identification code for the destination airfield, would be accepted

Role of Breast Cancer Resistance Protein (BCRP/ABCG2) in Cancer Drug Resistance

PubMed Central

Natarajan, Karthika; Xie, Yi; Baer, Maria R.; Ross, Douglas D.

2012-01-01

Since cloning of the ATP-binding cassette (ABC) family member breast cancer resistance protein (BCRP/ABCG2) and its characterization as a multidrug resistance efflux transporter in 1998, BCRP has been the subject of more than two thousand scholarly articles. In normal tissues, BCRP functions as a defense mechanism against toxins and xenobiotics, with expression in the gut, bile canaliculi, placenta, blood-testis and blood-brain barriers facilitating excretion and limiting absorption of potentially toxic substrate molecules, including many cancer chemotherapeutic drugs. BCRP also plays a key role in heme and folate homeostasis, which may help normal cells survive under conditions of hypoxia. BCRP expression appears to be a characteristic of certain normal tissue stem cells termed “side population cells,” which are identified on flow cytometric analysis by their ability to exclude Hoechst 33342, a BCRP substrate fluorescent dye. Hence, BCRP expression may contribute to the natural resistance and longevity of these normal stem cells. Malignant tissues can exploit the properties of BCRP to survive hypoxia and to evade exposure to chemotherapeutic drugs. Evidence is mounting that many cancers display subpopulations of stem cells that are responsible for tumor self-renewal. Such stem cells frequently manifest the “side population” phenotype characterized by expression of BCRP and other ABC transporters. Along with other factors, these transporters may contribute to the inherent resistance of these neoplasms and their failure to be cured. PMID:22248732

Diversity of ABC transporter genes across the plant kingdom and their potential utility in biotechnology.

PubMed

Lane, Thomas S; Rempe, Caroline S; Davitt, Jack; Staton, Margaret E; Peng, Yanhui; Soltis, Douglas Edward; Melkonian, Michael; Deyholos, Michael; Leebens-Mack, James H; Chase, Mark; Rothfels, Carl J; Stevenson, Dennis; Graham, Sean W; Yu, Jun; Liu, Tao; Pires, J Chris; Edger, Patrick P; Zhang, Yong; Xie, Yinlong; Zhu, Ying; Carpenter, Eric; Wong, Gane Ka-Shu; Stewart, C Neal

2016-05-31

The ATP-binding cassette (ABC) transporter gene superfamily is ubiquitous among extant organisms and prominently represented in plants. ABC transporters act to transport compounds across cellular membranes and are involved in a diverse range of biological processes. Thus, the applicability to biotechnology is vast, including cancer resistance in humans, drug resistance among vertebrates, and herbicide and other xenobiotic resistance in plants. In addition, plants appear to harbor the highest diversity of ABC transporter genes compared with any other group of organisms. This study applied transcriptome analysis to survey the kingdom-wide ABC transporter diversity in plants and suggest biotechnology applications of this diversity. We utilized sequence similarity-based informatics techniques to infer the identity of ABC transporter gene candidates from 1295 phylogenetically-diverse plant transcriptomes. A total of 97,149 putative (approximately 25 % were full-length) ABC transporter gene members were identified; each RNA-Seq library (plant sample) had 88 ± 30 gene members. As expected, simpler organisms, such as algae, had fewer unique members than vascular land plants. Differences were also noted in the richness of certain ABC transporter subfamilies. Land plants had more unique ABCB, ABCC, and ABCG transporter gene members on average (p < 0.005), and green algae, red algae, and bryophytes had significantly more ABCF transporter gene members (p < 0.005). Ferns had significantly fewer ABCA transporter gene members than all other plant groups (p < 0.005). We present a transcriptomic overview of ABC transporter gene members across all major plant groups. An increase in the number of gene family members present in the ABCB, ABCC, and ABCD transporter subfamilies may indicate an expansion of the ABC transporter superfamily among green land plants, which include all crop species. The striking difference between the number of ABCA subfamily transporter gene members between ferns and other plant taxa is surprising and merits further investigation. Discussed is the potential exploitation of ABC transporters in plant biotechnology, with an emphasis on crops.

Falls and confidence related quality of life outcome measures in an older British cohort

PubMed Central

Parry, S; Steen, N; Galloway, S; Kenny, R; Bond, J

2001-01-01

Falls are common in older subjects and result in loss of confidence and independence. The Falls Efficacy Scale (FES) and the Activities-specific Balance Confidence scale (ABC) were developed in North America to quantify these entities, but contain idiom unfamiliar to an older British population. Neither has been validated in the UK. The FES and the ABC were modified for use within British culture and the internal consistency and test-retest reliability of the modified scales (FES-UK and ABC-UK) assessed. A total of 193 consecutive, ambulant, new, and return patients (n=119; 62%) and their friends and relatives ("visitors", n=74; 38%) were tested on both scales, while the last 60 subjects were retested within one week. Internal reliability was excellent for both scales (Cronbach's alpha 0.97 (FES-UK), and 0.98 (ABC-UK)). Test-retest reliability was good for both scales, though superior for the ABC-UK (intraclass correlation coefficient 0.58 (FES-UK), 0.89 (ABC-UK)). There was evidence to suggest that the ABC-UK was better than the FES-UK at distinguishing between older patients and younger patients (|tABC| = 4.4; |tFES| = 2.3); and between fallers and non-fallers (|tABC| = 8.7; |tFES| = 5.0) where the t statistics are based on the comparison of two independent samples. The ABC-UK and FES-UK are both reliable and valid measures for the assessment of falls and balance related confidence in older adults. However, better test-retest reliability and more robust differentiation of subgroups in whom falls related quality of life would be expected to be different make the ABC-UK the current instrument of choice in assessing this entity in older British subjects.


Keywords: quality of life; falls; elderly; health status measurement PMID:11161077

Investigating the dynamic nature of the ABC transporters: ABCB1 and MsbA as examples for the potential synergies of MD theory and EPR applications.

PubMed

Stockner, Thomas; Mullen, Anna; MacMillan, Fraser

2015-10-01

ABC transporters are primary active transporters found in all kingdoms of life. Human multidrug resistance transporter ABCB1, or P-glycoprotein, has an extremely broad substrate spectrum and confers resistance against chemotherapy drug treatment in cancer cells. The bacterial ABC transporter MsbA is a lipid A flippase and a homolog to the human ABCB1 transporter, with which it partially shares its substrate spectrum. Crystal structures of MsbA and ABCB1 have been solved in multiple conformations, providing a glimpse into the possible conformational changes the transporter could be going through during the transport cycle. Crystal structures are inherently static, while a dynamic picture of the transporter in motion is needed for a complete understanding of transporter function. Molecular dynamics (MD) simulations and electron paramagnetic resonance (EPR) spectroscopy can provide structural information on ABC transporters, but the strength of these two methods lies in the potential to characterise the dynamic regime of these transporters. Information from the two methods is quite complementary. MD simulations provide an all atom dynamic picture of the time evolution of the molecular system, though with a narrow time window. EPR spectroscopy can probe structural, environmental and dynamic properties of the transporter in several time regimes, but only through the attachment sites of an exogenous spin label. In this review the synergistic effects that can be achieved by combining the two methods are highlighted, and a brief methodological background is also presented. © 2015 Authors; published by Portland Press Limited.

Hypoxia Induced Impairment of NK Cell Cytotoxicity against Multiple Myeloma Can Be Overcome by IL-2 Activation of the NK Cells

PubMed Central

Sarkar, Subhashis; Germeraad, Wilfred T. V.; Rouschop, Kasper M. A.; Steeghs, Elisabeth M. P.; van Gelder, Michel; Bos, Gerard M. J.; Wieten, Lotte

2013-01-01

Background Multiple Myeloma (MM) is an incurable plasma cell malignancy residing within the bone marrow (BM). We aim to develop allogeneic Natural Killer (NK) cell immunotherapy for MM. As the BM contains hypoxic regions and the tumor environment can be immunosuppressive, we hypothesized that hypoxia inhibits NK cell anti-MM responses. Methods NK cells were isolated from healthy donors by negative selection and NK cell function and phenotype were examined at oxygen levels representative of hypoxic BM using flowcytometry. Additionally, NK cells were activated with IL-2 to enhance NK cell cytotoxicity under hypoxia. Results Hypoxia reduced NK cell killing of MM cell lines in an oxygen dependent manner. Under hypoxia, NK cells maintained their ability to degranulate in response to target cells, though, the percentage of degranulating NK cells was slightly reduced. Adaptation of NK- or MM cells to hypoxia was not required, hence, the oxygen level during the killing process was critical. Hypoxia did not alter surface expression of NK cell ligands (HLA-ABC, -E, MICA/B and ULBP1-2) and receptors (KIR, NKG2A/C, DNAM-1, NCRs and 2B4). It did, however, decrease expression of the activating NKG2D receptor and of intracellular perforin and granzyme B. Pre-activation of NK cells by IL-2 abrogated the detrimental effects of hypoxia and increased NKG2D expression. This emphasized that activated NK cells can mediate anti-MM effects, even under hypoxic conditions. Conclusions Hypoxia abolishes the killing potential of NK cells against multiple myeloma, which can be restored by IL-2 activation. Our study shows that for the design of NK cell-based immunotherapy it is necessary to study biological interactions between NK- and tumor cells also under hypoxic conditions. PMID:23724099

Active Breathing Control for Hodgkin's Disease in Childhood and Adolescence: Feasibility, Advantages, and Limits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Claude, Line; Malet, Claude Phys.; Pommier, Pascal

2007-04-01

Purpose: The challenge in early Hodgkin's disease (HD) in children is to maintain good survival rates while sparing organs at risk. This study assesses the feasibility of active breathing control (ABC) in children, and compares normal tissue irradiation with and without ABC. Methods and Materials: Between May 2003 and June 2004, seven children with HD with mediastinal involvement, median age 15, were treated by chemotherapy and involved-field radiation therapy. A free-breathing computed tomography simulation scan and one additional scan during deep inspiration using ABC were performed. A comparison between planning treatment with clinical target volume including supraclavicular regions, mediastinum, andmore » hila was performed, both in free breathing and using ABC. Results: For a prescription of 36 Gy, pulmonary dose-volume histograms revealed a mean reduction in lung volume irradiated at more than 20 Gy (V20) and 30 Gy (V30) of 25% and 26%, respectively, using ABC (p = 0.016). The mean volume of heart irradiated at 30 Gy or more decreased from 15% to 12% (nonsignificant). The mean dose delivered to breasts in girls was small in both situations (less than 2 Gy) and stable with or without ABC. Considering axillary irradiation, the mean dose delivered to breasts remained low (<9 Gy), without significant difference using ABC or not. The mean radiation dose delivered to thyroid was stable using ABC or not. Conclusions: Using ABC is feasible in childhood. The use of ABC decreases normal lung tissue irradiation. Concerning heart irradiation, a minimal gain is also shown. No significant change has been demonstrated concerning breast and thyroid irradiation.« less

Inactivation of the Ecs ABC transporter of Staphylococcus aureus attenuates virulence by altering composition and function of bacterial wall.

PubMed

Jonsson, Ing-Marie; Juuti, Jarmo T; François, Patrice; AlMajidi, Rana; Pietiäinen, Milla; Girard, Myriam; Lindholm, Catharina; Saller, Manfred J; Driessen, Arnold J M; Kuusela, Pentti; Bokarewa, Maria; Schrenzel, Jacques; Kontinen, Vesa P

2010-12-02

Ecs is an ATP-binding cassette (ABC) transporter present in aerobic and facultative anaerobic gram-positive Firmicutes. Inactivation of Bacillus subtilis Ecs causes pleiotropic changes in the bacterial phenotype including inhibition of intramembrane proteolysis. The molecule(s) transported by Ecs is (are) still unknown. In this study we mutated the ecsAB operon in two Staphylococcus aureus strains, Newman and LS-1. Phenotypic and functional characterization of these Ecs deficient mutants revealed a defect in growth, increased autolysis and lysostaphin sensitivity, altered composition of cell wall proteins including the precursor form of staphylokinase and an altered bacterial surface texture. DNA microarray analysis indicated that the Ecs deficiency changed expression of the virulence factor regulator protein Rot accompanied by differential expression of membrane transport proteins, particularly ABC transporters and phosphate-specific transport systems, protein A, adhesins and capsular polysaccharide biosynthesis proteins. Virulence of the ecs mutants was studied in a mouse model of hematogenous S. aureus infection. Mice inoculated with the ecs mutant strains developed markedly milder infections than those inoculated with the wild-type strains and had consequently lower mortality, less weight loss, milder arthritis and decreased persistence of staphylococci in the kidneys. The ecs mutants had higher susceptibility to ribosomal antibiotics and plant alkaloids chelerythrine and sanguinarine. Our results show that Ecs is essential for staphylococcal virulence and antimicrobial resistance probably since the transport function of Ecs is essential for the normal structure and function of the cell wall. Thus targeting Ecs may be a new approach in combating staphylococcal infection.

Phase 0 and phase III transport in various organs: combined concept of phases in xenobiotic transport and metabolism.

PubMed

Döring, Barbara; Petzinger, Ernst

2014-08-01

The historical phasing concept of drug metabolism and elimination was introduced to comprise the two phases of metabolism: phase I metabolism for oxidations, reductions and hydrolyses, and phase II metabolism for synthesis. With this concept, biological membrane barriers obstructing the accessibility of metabolism sites in the cells for drugs were not considered. The concept of two phases was extended to a concept of four phases when drug transporters were detected that guided drugs and drug metabolites in and out of the cells. In particular, water soluble or charged drugs are virtually not able to overcome the phospholipid membrane barrier. Drug transporters belong to two main clusters of transporter families: the solute carrier (SLC) families and the ATP binding cassette (ABC) carriers. The ABC transporters comprise seven families with about 20 carriers involved in drug transport. All of them operate as pumps at the expense of ATP splitting. Embedded in the former phase concept, the term "phase III" was introduced by Ishikawa in 1992 for drug export by ABC efflux pumps. SLC comprise 52 families, from which many carriers are drug uptake transporters. Later on, this uptake process was referred to as the "phase 0 transport" of drugs. Transporters for xenobiotics in man and animal are most expressed in liver, but they are also present in extra-hepatic tissues such as in the kidney, the adrenal gland and lung. This review deals with the function of drug carriers in various organs and their impact on drug metabolism and elimination.

Export of Extracellular Polysaccharides Modulates Adherence of the Cyanobacterium Synechocystis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisher, ML; Allen, R; Luo, YQ

2013-09-10

The field of cyanobacterial biofuel production is advancing rapidly, yet we know little of the basic biology of these organisms outside of their photosynthetic pathways. We aimed to gain a greater understanding of how the cyanobacterium Synechocystis PCC 6803 (Synechocystis, hereafter) modulates its cell surface. Such understanding will allow for the creation of mutants that autoflocculate in a regulated way, thus avoiding energy intensive centrifugation in the creation of biofuels. We constructed mutant strains lacking genes predicted to function in carbohydrate transport or synthesis. Strains with gene deletions of slr0977 (predicted to encode a permease component of an ABC transporter),more » slr0982 (predicted to encode an ATP binding component of an ABC transporter) and slr1610 (predicted to encode a methyltransferase) demonstrated flocculent phenotypes and increased adherence to glass. Upon bioinformatic inspection, the gene products of slr0977, slr0982, and slr1610 appear to function in O-antigen (OAg) transport and synthesis. However, the analysis provided here demonstrated no differences between OAg purified from wild-type and mutants. However, exopolysaccharides (EPS) purified from mutants were altered in composition when compared to wild-type. Our data suggest that there are multiple means to modulate the cell surface of Synechocystis by disrupting different combinations of ABC transporters and/or glycosyl transferases. Further understanding of these mechanisms may allow for the development of industrially and ecologically useful strains of cyanobacteria. Additionally, these data imply that many cyanobacterial gene products may possess as-yet undiscovered functions, and are meritorious of further study.« less

Abacavir/Lamivudine plus Rilpivirine Is an Effective and Safe Strategy for HIV-1 Suppressed Patients: 48 Week Results of the SIMRIKI Retrospective Study

PubMed Central

Troya, Jesús; Ryan, Pablo; Ribera, Esteban; Podzamczer, Daniel; Hontañón, Victor; Terrón, Jose Alberto; Boix, Vicente; Moreno, Santiago; Barrufet, Pilar; Castaño, Manuel; Carrero, Ana; Galindo, María José; Suárez-Lozano, Ignacio; Knobel, Hernando; Raffo, Miguel; Solís, Javier; Yllescas, María; Esteban, Herminia

2016-01-01

Objectives Based on data from clinical practice, we evaluated the effectiveness and safety of switching to abacavir/lamivudine plus rilpivirine (ABC/3TC+RPV) treatment in virologically suppressed HIV-1-infected patients. Methods We performed a multicenter, non-controlled, retrospective study of HIV-1-infected patients who switched treatment to ABC/3TC+RPV. Patients had an HIV-RNA <50 copies/mL for at least 24 weeks prior to changing treatments. The primary objective was HIV-1 RNA <50 copies/mL at week 48. Effectiveness was analyzed by intention-to-treat (ITT), missing = failure and on-treatment (OT) analyses. The secondary objectives analyzed were adverse effects changes in renal, hepatic or lipid profiles, changes in CD4+ cell count and treatment discontinuations. Results Of the 205 patients included, 75.6% were men and the median age was 49. At baseline, before switching to ABC/3TC+RPV, median time since HIV diagnosis was 13.1 years, median time with undetectable HIV-1 RNA was 6.2 years and median time of previous antiretroviral regimen was 3.1 years (48.3% patients were taking efavirenz and ABC/3TC was the most frequent backbone coformulation in 69.7% of patients). The main reasons for switching were drug toxicity/poor tolerability (60.5%) and simplification (20%). At week 48, the primary objective was achieved by 187 out of 205 (91.2%) patients by ITT analysis, and 187 out of 192 (97.4%) patients by OT analysis. The CD4+ lymphocyte count and CD4+ percentage increased significantly from baseline to week 48 by a median of 48 cells/μL (−50 to 189) and 1.2% (−1.3% to 4.1%), respectively, P<0.001. Thirty-eight adverse events (AE) were detected in 32 patients. Of these, 25 had no clear association with treatment. Three patients interrupted therapy due to AE. We observed a decrease in all lipid parameters, P<0.001, and a slight improvement in the glomerular filtration rate, P<0.01. Therapy was considered to have failed in 18 patients owing to virological failure (5 [2.4%]), toxicity/poor tolerability (4 [2%]), clinical decision (3 [1.5%]), loss to follow-up (3 [1.5%]), death (1 [0.5%]), and no clinical data (2 [1%]). Conclusions The results of this study confirms that ABC/3TC+RPV is an effective, safe, and cost-effective option for the treatment of patients with virologically stable HIV-1 infection. PMID:27727331

Parameter Estimation for a Turbulent Buoyant Jet Using Approximate Bayesian Computation

NASA Astrophysics Data System (ADS)

Christopher, Jason D.; Wimer, Nicholas T.; Hayden, Torrey R. S.; Lapointe, Caelan; Grooms, Ian; Rieker, Gregory B.; Hamlington, Peter E.

2016-11-01

Approximate Bayesian Computation (ABC) is a powerful tool that allows sparse experimental or other "truth" data to be used for the prediction of unknown model parameters in numerical simulations of real-world engineering systems. In this presentation, we introduce the ABC approach and then use ABC to predict unknown inflow conditions in simulations of a two-dimensional (2D) turbulent, high-temperature buoyant jet. For this test case, truth data are obtained from a simulation with known boundary conditions and problem parameters. Using spatially-sparse temperature statistics from the 2D buoyant jet truth simulation, we show that the ABC method provides accurate predictions of the true jet inflow temperature. The success of the ABC approach in the present test suggests that ABC is a useful and versatile tool for engineering fluid dynamics research.

LhnR and upstream operon LhnABC in Agrobacterium vitis regulate the induction of tobacco hypersensitive responses, grape necrosis and swarming motility.

PubMed

Zheng, Desen; Hao, Guixia; Cursino, Luciana; Zhang, Hongsheng; Burr, Thomas J

2012-09-01

The characterization of Tn5 transposon insertional mutants of Agrobacterium vitis strain F2/5 revealed a gene encoding a predicted LysR-type transcriptional regulator, lhnR (for 'LysR-type regulator associated with HR and necrosis'), and an immediate upstream operon consisting of three open reading frames (lhnABC) required for swarming motility, surfactant production and the induction of a hypersensitive response (HR) on tobacco and necrosis on grape. The operon lhnABC is unique to A. vitis among the sequenced members in Rhizobiaceae. Mutagenesis of lhnR and lhnABC by gene disruption and complementation of ΔlhnR and ΔlhnABC confirmed their roles in the expression of these phenotypes. Mutation of lhnR resulted in complete loss of HR, swarming motility, surfactant production and reduced necrosis, whereas mutation of lhnABC resulted in loss of swarming motility, delayed and reduced HR development and reduced surfactant production and necrosis. The data from promoter-green fluorescent protein (gfp) fusions showed that lhnR suppresses the expression of lhnABC and negatively autoregulates its own expression. It was also shown that lhnABC negatively affects its own expression and positively affects the transcription of lhnR. lhnR and lhnABC constitute a regulatory circuit that coordinates the transcription level of lhnR, resulting in the expression of swarming, surfactant, HR and necrosis phenotypes. © 2012 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

Two Topologically Distinct Dirac-Line Semimetal Phases and Topological Phase Transitions in Rhombohedrally Stacked Honeycomb Lattices

NASA Astrophysics Data System (ADS)

Hyart, T.; Ojajärvi, R.; Heikkilä, T. T.

2018-04-01

Three-dimensional topological semimetals can support band crossings along one-dimensional curves in the momentum space (nodal lines or Dirac lines) protected by structural symmetries and topology. We consider rhombohedrally (ABC) stacked honeycomb lattices supporting Dirac lines protected by time-reversal, inversion and spin rotation symmetries. For typical band structure parameters there exists a pair of nodal lines in the momentum space extending through the whole Brillouin zone in the stacking direction. We show that these Dirac lines are topologically distinct from the usual Dirac lines which form closed loops inside the Brillouin zone. In particular, an energy gap can be opened only by first merging the Dirac lines going through the Brillouin zone in a pairwise manner so that they turn into closed loops inside the Brillouin zone, and then by shrinking these loops into points. We show that this kind of topological phase transition can occur in rhombohedrally stacked honeycomb lattices by tuning the ratio of the tunneling amplitudes in the directions perpendicular and parallel to the layers. We also discuss the properties of the surface states in the different phases of the model.

Our bodies are our own: resistance to ABC-based HIV-prevention programmes in northern Tanzanian conservation organisations.

PubMed

Reid-Hresko, John

2014-01-01

ABC-based HIV-prevention programmes have been widely employed in northern Tanzanian wildlife conservation settings in an attempt to (re)shape the sexual behaviours of conservation actors. Utilising findings from 66 semi-structured interviews conducted in 2009-2010, this paper examines ABC prevention as a form of Foucauldian governmentality--circulating technologies of power that mobilise disciplinary technologies and attempt to transform such efforts into technologies of the self--and explores how individuals understand and respond to attempts to govern their behaviour. ABC regimes attempt to rework subjectivity, positioning HIV-related behaviours within a risk-based neoliberal rationality. However, efforts to use ABC as a technology to govern populations and individual bodies are largely incommensurate with existing Tanzanian sociocultural formations, including economic and gendered inequalities, and local understandings of sexuality. The language research participants used to talk about ABC and the justifications they offered for non-compliance illuminate this discrepancy. Data reveal that the recipients of ABC campaigns are active producers of understandings that work for them in their lives, but may not produce the behavioural shifts envisioned by programme goals. These findings corroborate previous research, which questions the continued plausibility of ABC as a stand-alone HIV- prevention framework.

Applying Activity Based Costing (ABC) Method to Calculate Cost Price in Hospital and Remedy Services

PubMed Central

Rajabi, A; Dabiri, A

2012-01-01

Background Activity Based Costing (ABC) is one of the new methods began appearing as a costing methodology in the 1990’s. It calculates cost price by determining the usage of resources. In this study, ABC method was used for calculating cost price of remedial services in hospitals. Methods: To apply ABC method, Shahid Faghihi Hospital was selected. First, hospital units were divided into three main departments: administrative, diagnostic, and hospitalized. Second, activity centers were defined by the activity analysis method. Third, costs of administrative activity centers were allocated into diagnostic and operational departments based on the cost driver. Finally, with regard to the usage of cost objectives from services of activity centers, the cost price of medical services was calculated. Results: The cost price from ABC method significantly differs from tariff method. In addition, high amount of indirect costs in the hospital indicates that capacities of resources are not used properly. Conclusion: Cost price of remedial services with tariff method is not properly calculated when compared with ABC method. ABC calculates cost price by applying suitable mechanisms but tariff method is based on the fixed price. In addition, ABC represents useful information about the amount and combination of cost price services. PMID:23113171

MetaABC--an integrated metagenomics platform for data adjustment, binning and clustering.

PubMed

Su, Chien-Hao; Hsu, Ming-Tsung; Wang, Tse-Yi; Chiang, Sufeng; Cheng, Jen-Hao; Weng, Francis C; Kao, Cheng-Yan; Wang, Daryi; Tsai, Huai-Kuang

2011-08-15

MetaABC is a metagenomic platform that integrates several binning tools coupled with methods for removing artifacts, analyzing unassigned reads and controlling sampling biases. It allows users to arrive at a better interpretation via series of distinct combinations of analysis tools. After execution, MetaABC provides outputs in various visual formats such as tables, pie and bar charts as well as clustering result diagrams. MetaABC source code and documentation are available at http://bits2.iis.sinica.edu.tw/MetaABC/ CONTACT: dywang@gate.sinica.edu.tw; hktsai@iis.sinica.edu.tw Supplementary data are available at Bioinformatics online.

Sulfadiazine resistance in Toxoplasma gondii: no involvement of overexpression or polymorphisms in genes of therapeutic targets and ABC transporters

PubMed Central

Doliwa, Christelle; Escotte-Binet, Sandie; Aubert, Dominique; Sauvage, Virginie; Velard, Frédéric; Schmid, Aline; Villena, Isabelle

2013-01-01

Several treatment failures have been reported for the treatment of toxoplasmic encephalitis, chorioretinitis, and congenital toxoplasmosis. Recently we found three Toxoplasma gondii strains naturally resistant to sulfadiazine and we developed in vitro two sulfadiazine resistant strains, RH-RSDZ and ME-49-RSDZ, by gradual pressure. In Plasmodium, common mechanisms of drug resistance involve, among others, mutations and/or amplification within genes encoding the therapeutic targets dhps and dhfr and/or the ABC transporter genes family. To identify genotypic and/or phenotypic markers of resistance in T. gondii, we sequenced and analyzed the expression levels of therapeutic targets dhps and dhfr, three ABC genes, two Pgp, TgABC.B1 and TgABC.B2, and one MRP, TgABC.C1, on sensitive strains compared to sulfadiazine resistant strains. Neither polymorphism nor overexpression was identified. Contrary to Plasmodium, in which mutations and/or overexpression within gene targets and ABC transporters are involved in antimalarial resistance, T. gondii sulfadiazine resistance is not related to these toxoplasmic genes studied. PMID:23707894

Optimization of Straight Cylindrical Turning Using Artificial Bee Colony (ABC) Algorithm

NASA Astrophysics Data System (ADS)

Prasanth, Rajanampalli Seshasai Srinivasa; Hans Raj, Kandikonda

2017-04-01

Artificial bee colony (ABC) algorithm, that mimics the intelligent foraging behavior of honey bees, is increasingly gaining acceptance in the field of process optimization, as it is capable of handling nonlinearity, complexity and uncertainty. Straight cylindrical turning is a complex and nonlinear machining process which involves the selection of appropriate cutting parameters that affect the quality of the workpiece. This paper presents the estimation of optimal cutting parameters of the straight cylindrical turning process using the ABC algorithm. The ABC algorithm is first tested on four benchmark problems of numerical optimization and its performance is compared with genetic algorithm (GA) and ant colony optimization (ACO) algorithm. Results indicate that, the rate of convergence of ABC algorithm is better than GA and ACO. Then, the ABC algorithm is used to predict optimal cutting parameters such as cutting speed, feed rate, depth of cut and tool nose radius to achieve good surface finish. Results indicate that, the ABC algorithm estimated a comparable surface finish when compared with real coded genetic algorithm and differential evolution algorithm.

ABC1 Consensus Conference - a German Perspective: First International Consensus Conference on Advanced Breast Cancer (ABC1), Lisbon, November 5, 2011.

PubMed

Thomssen, Christoph; Marschner, Norbert; Untch, Michael; Decker, Thomas; Hegewisch-Becker, Susanna; Jackisch, Christian; Janni, Wolfgang; Hans-Joachim, Lück; von Minckwitz, Gunter; Scharl, Anton; Schneeweiss, Andreas; Tesch, Hans; Welt, Anja; Harbeck, Nadia

2012-02-01

A group of German breast cancer experts (medical oncologists and gynaecologists) reviewed and commented on the results of the first international 'Advanced Breast Cancer First Consensus Conference' (ABC1) for the diagnosis and treatment of advanced breast cancer. The ABC1 Conference is an initiative of the European School of Oncology (ESO) Metastatic Breast Cancer Task Force in cooperation with the EBCC (European Breast Cancer Conference), ESMO (European Society of Medical Oncology) and the American JNCI (Journal of the National Cancer Institute). The main focus of the ABC1 Conference was metastatic breast cancer (stage IV). The ABC1 consensus is based on the vote of 33 breast cancer experts from different countries and has been specified as a guideline for therapeutic practice by the German expert group. It is the objective of the ABC1 consensus as well as of the German comments to provide an internationally standardized and evidence-based foundation for qualified decision-making in the treatment of metastatic breast cancer.

Implementation and comparative analysis of the optimisations produced by evolutionary algorithms for the parameter extraction of PSP MOSFET model

NASA Astrophysics Data System (ADS)

Hadia, Sarman K.; Thakker, R. A.; Bhatt, Kirit R.

2016-05-01

The study proposes an application of evolutionary algorithms, specifically an artificial bee colony (ABC), variant ABC and particle swarm optimisation (PSO), to extract the parameters of metal oxide semiconductor field effect transistor (MOSFET) model. These algorithms are applied for the MOSFET parameter extraction problem using a Pennsylvania surface potential model. MOSFET parameter extraction procedures involve reducing the error between measured and modelled data. This study shows that ABC algorithm optimises the parameter values based on intelligent activities of honey bee swarms. Some modifications have also been applied to the basic ABC algorithm. Particle swarm optimisation is a population-based stochastic optimisation method that is based on bird flocking activities. The performances of these algorithms are compared with respect to the quality of the solutions. The simulation results of this study show that the PSO algorithm performs better than the variant ABC and basic ABC algorithm for the parameter extraction of the MOSFET model; also the implementation of the ABC algorithm is shown to be simpler than that of the PSO algorithm.

Incision of trivalent chromium [Cr(III)]-induced DNA damage by Bacillus caldotenax UvrABC endonuclease.

PubMed

O'Brien, Travis J; Jiang, Guohui; Chun, Gina; Mandel, H George; Westphal, Craig S; Kahen, Kaveh; Montaser, Akbar; States, J Christopher; Patierno, Steven R

2006-11-07

Some hexavalent chromium [Cr(VI)]-containing compounds are lung carcinogens. Once within cells, Cr(VI) is reduced to trivalent chromium [Cr(III)] which displays an affinity for both DNA bases and the phosphate backbone. A diverse array of genetic lesions is produced by Cr including Cr-DNA monoadducts, DNA interstrand crosslinks (ICLs), DNA-Cr-protein crosslinks (DPCs), abasic sites, DNA strand breaks and oxidized bases. Despite the large amount of information available on the genotoxicity of Cr, little is known regarding the molecular mechanisms involved in the removal of these lesions from damaged DNA. Recent work indicates that nucleotide excision repair (NER) is involved in the processing of Cr-DNA adducts in human and rodent cells. In order to better understand this process at the molecular level and begin to identify the Cr-DNA adducts processed by NER, the incision of CrCl(3) [Cr(III)]-damaged plasmid DNA was studied using a thermal-resistant UvrABC NER endonuclease from Bacillus caldotenax (Bca). Treatment of plasmid DNA with Cr(III) (as CrCl(3)) increased DNA binding as a function of dose. For example, at a Cr(III) concentration of 1 microM we observed approximately 2 Cr(III)-DNA adducts per plasmid. At this same concentration of Cr(III) we found that approximately 17% of the plasmid DNA contained ICLs ( approximately 0.2 ICLs/plasmid). When plasmid DNA treated with Cr(III) (1 microM) was incubated with Bca UvrABC we observed approximately 0.8 incisions/plasmid. The formation of endonuclease IV-sensitive abasic lesions or Fpg-sensitive oxidized DNA bases was not detected suggesting that the incision of Cr(III)-damaged plasmid DNA by UvrABC was not related to the generation of oxidized DNA damage. Taken together, our data suggest that a sub-fraction of Cr(III)-DNA adducts is recognized and processed by the prokaryotic NER machinery and that ICLs are not necessarily the sole lesions generated by Cr(III) that are substrates for NER.

The Role of ABC Proteins in Drug Resistant Breast Cancer Cells

DTIC Science & Technology

2009-03-01

7] Morris DI, Greenberger LM, Bruggemann EP, Carda relli C, Gottesman MM, Pastan I and Seamon KB. (1994) Localization of the forskolin labeling...sites to both h alves of P-glycoprotein: similarity of the sites labeled by forskolin and prazosin. Mol Pharmacol. 46(2): 329-37. [8] Cooper RA

CGI-58, a key regulator of lipid homeostasis and signaling in plants, also regulates polyamine metabolism

USDA-ARS?s Scientific Manuscript database

Comparative Gene Identification-58 (CGI-58) is an alpha/beta hydrolase-type protein that regulates lipid homeostasis and signaling in eukaryotes by interacting with and stimulating the activity of several different types of proteins, including a lipase in mammalian cells and a peroxisomal ABC transp...

Role of the cell envelope stress regulators BaeR and CpxR in control of RND-type multidrug efflux pumps and transcriptional cross talk with exopolysaccharide synthesis in Erwinia amylovora.

PubMed

Pletzer, Daniel; Stahl, Antje; Oja, Anna Elisabeth; Weingart, Helge

2015-08-01

The purpose of this study was to identify the role of the cell envelope stress-sensing systems BaeSR and CpxARP in regulation of multidrug efflux and exopolysaccharide synthesis in Erwinia amylovora. We have previously reported that BaeR activates transcription of the RND-type efflux pumps AcrD and MdtABC. In this study, we found that a cpxR-deficient mutant was highly susceptible to β-lactams, aminoglycosides and lincomycin, whereas a baeR mutant showed no change in antimicrobial sensitivity. However, overexpression of BaeR in a mutant lacking the major RND pump AcrB increased resistance of E. amylovora to several compounds that are not substrates of AcrD or MdtABC. Furthermore, we observed that overexpression of BaeR significantly increased amylovoran production. Moreover, the expression of RND-type efflux pumps was changed in regulatory mutants of exopolysaccharide production. Our data suggest that BaeSR and CpxARP regulate additional mechanisms, beside efflux, which are responsible for antimicrobial resistance of E. amylovora.

Retinal-specific ATP-binding cassette transporter (ABCR/ABCA4) is expressed at the choroid plexus in rat brain.

PubMed

Bhongsatiern, Jiraganya; Ohtsuki, Sumio; Tachikawa, Masanori; Hori, Satoko; Terasaki, Tetsuya

2005-03-01

ATP-binding cassette (ABC) transporter A4 is a member of the ABC transporter subfamily A which has been reported to be exclusively expressed in the retina. In contrast, a previous report has suggested a possible relationship between ABCA4 and CNS function. The purpose of the present study was to investigate the localization of ABCA4 mRNA and protein in rat brain. In situ hybridization analysis revealed that ABCA4 mRNA was localized in the lateral ventricles. RT-PCR analysis detected ABCA4 mRNA in isolated rat choroid plexus and conditionally immortalized rat choroid plexus epithelial cells (TR-CSFB). Furthermore, ABCA4 protein was also detected in the isolated rat choroid plexus at about 250 kDa by western blot analysis, and its apparent molecular size was reduced by N-glycosidase F treatment. These results suggest that glycosylated ABCA4 protein is expressed in rat choroid plexus epithelial cells. ABCA4 may play a role in the function of the blood-cerebrospinal fluid barrier and affect CSF conditions.

Bombyx mori ABC transporter C2 structures responsible for the receptor function of Bacillus thuringiensis Cry1Aa toxin.

PubMed

Tanaka, Shiho; Endo, Haruka; Adegawa, Satomi; Iizuka, Ami; Imamura, Kazuhiro; Kikuta, Shingo; Sato, Ryoichi

2017-12-01

Because Bombyx mori ABC transporter C2 (BmABCC2) has 1000-fold higher potential than B. mori cadherin-like protein as a receptor for Bacillus thuringiensis Cry1Aa toxin (Tanaka et al., 2013), the gate-opening ability of the latent pore under six extracellular loops (ECLs) of BmABCC2 was expected to be the reason for its higher potential (Heckel, 2012). In this study, cell swelling assays in Sf9 cells showed that BmABCC2 mutants lacking substrate-excreting activity retained receptor activity, indicating that the gate-opening activity of BmABCC2 is not responsible for Cry1Aa toxicity. The analysis of 29 BmABCC2 mutants demonstrated that 770 DYWL 773 of ECL 4 comprise a putative binding site to Cry1Aa. This suggests that specific toxicity of Cry1Aa toxin to a restricted range of lepidopteran insects is dependent on conservation and variation in the amino acid residues around 770 DYWL 773 of ECL 4 in the ABCC2. Copyright © 2017 Elsevier Ltd. All rights reserved.

Iowa ABC connections : [tech transfer summary].

DOT National Transportation Integrated Search

2015-06-01

The Iowa Department of Transportation (DOT) and other organizations have : been developing accelerated bridge construction (ABC) concepts, details, and : processes, and Iowa has come to be viewed as a national leader in the area of : ABC. However, th...

Rhombohedral Multilayer Graphene: A Magneto-Raman Scattering Study.

PubMed

Henni, Younes; Ojeda Collado, Hector Pablo; Nogajewski, Karol; Molas, Maciej R; Usaj, Gonzalo; Balseiro, Carlos A; Orlita, Milan; Potemski, Marek; Faugeras, Clement

2016-06-08

Graphene layers are known to stack in two stable configurations, namely, ABA or ABC stacking, with drastically distinct electronic properties. Unlike the ABA stacking, little has been done to experimentally investigate the electronic properties of ABC graphene multilayers. Here, we report on the first magneto optical study of a large ABC domain in a graphene multilayer flake, with ABC sequences exceeding 17 graphene sheets. ABC-stacked multilayers can be fingerprinted with a characteristic electronic Raman scattering response, which persists even at room temperatures. Tracing the magnetic field evolution of the inter Landau level excitations from this domain gives strong evidence for the existence of a dispersionless electronic band near the Fermi level, characteristic of such stacking. Our findings present a simple yet powerful approach to probe ABC stacking in graphene multilayer flakes, where this highly degenerated band appears as an appealing candidate to host strongly correlated states.

Modified artificial bee colony algorithm for reactive power optimization

NASA Astrophysics Data System (ADS)

Sulaiman, Noorazliza; Mohamad-Saleh, Junita; Abro, Abdul Ghani

2015-05-01

Bio-inspired algorithms (BIAs) implemented to solve various optimization problems have shown promising results which are very important in this severely complex real-world. Artificial Bee Colony (ABC) algorithm, a kind of BIAs has demonstrated tremendous results as compared to other optimization algorithms. This paper presents a new modified ABC algorithm referred to as JA-ABC3 with the aim to enhance convergence speed and avoid premature convergence. The proposed algorithm has been simulated on ten commonly used benchmarks functions. Its performance has also been compared with other existing ABC variants. To justify its robust applicability, the proposed algorithm has been tested to solve Reactive Power Optimization problem. The results have shown that the proposed algorithm has superior performance to other existing ABC variants e.g. GABC, BABC1, BABC2, BsfABC dan IABC in terms of convergence speed. Furthermore, the proposed algorithm has also demonstrated excellence performance in solving Reactive Power Optimization problem.

Interaction of oligomeric breast cancer resistant protein (BCRP) with adjudin: a male contraceptive with anti-cancer activity.

PubMed

Cheng, Yan Ho; Jenardhanan, Pranitha; Mathur, Premendu P; Qian, Xiaojing; Xia, Weiliang; Silvestrini, Bruno; Cheng, Chuen Yan

2014-01-01

Breast cancer resistant protein (BCRP, ABCG2) is an ATP-binding cassette (ABC) transporter, which together with two other ABC efflux drug pumps, namely P-glycoprotein (P-gp, ABCB1) and multidrug resistance-related protein 1 (MRP1, ABCC1) is the most important multidrug resistance protein foun d in eukaryotic cells including cells in the testis. However, unlike P-gp and MRP1, which are components of the Sertoli cell blood-testis barrier (BTB), BCRP is not expressed at the BTB in rodents and human testes. Instead, BCRP is expressed by peritubular myoid cells and endothelial cells of the lymphatic vessel in the tunica propria, residing outside the BTB. As such, the testis is equipped with two levels of defense against xenobiotics or drugs, preventing these harmful substances from entering the adluminal compartment to perturb meiosis and post-meiotic spermatid development: one at the level of the BTB conferred by P-gp and MRP1 and one at the tunica propria conferred by BCRP. The presence of drug transporters at the tunica propria as well as at the Sertoli cell BTB thus poses significant obstacles in developing non-hormonal contraceptives if these drugs (e.g., adjudin) exert their effects in germ cells behind the BTB, such as in the adluminal (apical) compartment of the seminiferous epithelium. Herein, we summarize recent findings pertinent to adjudin, a non-hormonal male contraceptive, and molecular interactions of adjudin with BCRP so that this information can be helpful to devise delivery strategies to evade BCRP in the tunica propria to improve its bioavailability in the testis.

Preclinical properties and human in vivo assessment of 123 I-ABC577 as a novel SPECT agent for imaging amyloid-β

PubMed Central

Okumura, Yuki; Kobayashi, Ryohei; Onishi, Takako; Shoyama, Yoshinari; Barret, Olivier; Alagille, David; Jennings, Danna; Marek, Kenneth; Seibyl, John; Tamagnan, Gilles; Tanaka, Akihiro; Shirakami, Yoshifumi

2016-01-01

Abstract Non-invasive imaging of amyloid-β in the brain, a hallmark of Alzheimer’s disease, may support earlier and more accurate diagnosis of the disease. In this study, we assessed the novel single photon emission computed tomography tracer 123 I-ABC577 as a potential imaging biomarker for amyloid-β in the brain. The radio-iodinated imidazopyridine derivative 123 I-ABC577 was designed as a candidate for a novel amyloid-β imaging agent. The binding affinity of 123 I-ABC577 for amyloid-β was evaluated by saturation binding assay and in vitro autoradiography using post-mortem Alzheimer’s disease brain tissue. Biodistribution experiments using normal rats were performed to evaluate the biokinetics of 123 I-ABC577. Furthermore, to validate 123 I-ABC577 as a biomarker for Alzheimer’s disease, we performed a clinical study to compare the brain uptake of 123 I-ABC577 in three patients with Alzheimer’s disease and three healthy control subjects. 123 I-ABC577 binding was quantified by use of the standardized uptake value ratio, which was calculated for the cortex using the cerebellum as a reference region. Standardized uptake value ratio images were visually scored as positive or negative. As a result, 123 I-ABC577 showed high binding affinity for amyloid-β and desirable pharmacokinetics in the preclinical studies. In the clinical study, 123 I-ABC577 was an effective marker for discriminating patients with Alzheimer’s disease from healthy control subjects based on visual images or the ratio of cortical-to-cerebellar binding. In patients with Alzheimer’s disease, 123 I-ABC577 demonstrated clear retention in cortical regions known to accumulate amyloid, such as the frontal cortex, temporal cortex, and posterior cingulate. In contrast, less, more diffuse, and non-specific uptake without localization to these key regions was observed in healthy controls. At 150 min after injection, the cortical standardized uptake value ratio increased by ∼60% in patients with Alzheimer’s disease relative to healthy control subjects. Both healthy control subjects and patients with Alzheimer’s disease showed minimal 123 I-ABC577 retention in the white matter. These observations indicate that 123 I-ABC577 may be a useful single photon emission computed tomography imaging maker to identify amyloid-β in the human brain. The availability of an amyloid-β tracer for single photon emission computed tomography might increase the accessibility of diagnostic imaging for Alzheimer’s disease. PMID:26490333

Expressing Constitutively Active Rheb in Adult Dorsal Root Ganglion Neurons Enhances the Integration of Sensory Axons that Regenerate Across a Chondroitinase-Treated Dorsal Root Entry Zone Following Dorsal Root Crush

PubMed Central

Wu, Di; Klaw, Michelle C.; Kholodilov, Nikolai; Burke, Robert E.; Detloff, Megan R.; Côté, Marie-Pascale; Tom, Veronica J.

2016-01-01

While the peripheral branch of dorsal root ganglion neurons (DRG) can successfully regenerate after injury, lesioned central branch axons fail to regrow across the dorsal root entry zone (DREZ), the interface between the dorsal root and the spinal cord. This lack of regeneration is due to the limited regenerative capacity of adult sensory axons and the growth-inhibitory environment at the DREZ, which is similar to that found in the glial scar after a central nervous system (CNS) injury. We hypothesized that transduction of adult DRG neurons using adeno-associated virus (AAV) to express a constitutively-active form of the GTPase Rheb (caRheb) will increase their intrinsic growth potential after a dorsal root crush. Additionally, we posited that if we combined that approach with digestion of upregulated chondroitin sulfate proteoglycans (CSPG) at the DREZ with chondroitinase ABC (ChABC), we would promote regeneration of sensory axons across the DREZ into the spinal cord. We first assessed if this strategy promotes neuritic growth in an in vitro model of the glial scar containing CSPG. ChABC allowed for some regeneration across the once potently inhibitory substrate. Combining ChABC treatment with expression of caRheb in DRG significantly improved this growth. We then determined if this combination strategy also enhanced regeneration through the DREZ after dorsal root crush in adult rats in vivo. After unilaterally crushing C4-T1 dorsal roots, we injected AAV5-caRheb or AAV5-GFP into the ipsilateral C5-C8 DRGs. ChABC or PBS was injected into the ipsilateral dorsal horn at C5-C8 to digest CSPG, for a total of four animal groups (caRheb + ChABC, caRheb + PBS, GFP + ChABC, GFP + PBS). Regeneration was rarely observed in PBS-treated animals, whereas short-distance regrowth across the DREZ was observed in ChABC-treated animals. No difference in axon number or length between the ChABC groups was observed, which may be related to intraganglionic inflammation induced by the injection. ChABC-mediated regeneration is functional, as stimulation of ipsilateral median and ulnar nerves induced neuronal c-Fos expression in deafferented dorsal horn in both ChABC groups. Interestingly, caRheb + ChABC animals had significantly more c-Fos+ nuclei indicating that caRheb expression in DRGs promoted functional synaptogenesis of their axons that regenerated beyond a ChABC-treated DREZ. PMID:27458339

ABC-B transporter genes in Dirofilaria immitis.

PubMed

Bourguinat, Catherine; Che, Hua; Mani, Thangadurai; Keller, Kathy; Prichard, Roger K

2016-08-01

Dirofilaria immitis is a filarial nematode causing infection and heartworm disease in dogs and other canids, cats, and occasionally in humans. Prevention with macrocyclic lactones (ML) is recommended during the mosquito transmission season. Recently, ML resistance has been reported. ABC-B transporter genes are thought to be involved in the mechanism of ML resistance in other nematodes. This study aimed to identify all the ABC-B transporter genes in D. immitis using as a reference the nDi.2.2 D. immitis whole genome, which is not completely annotated. Using bioinformatic tools and PCR amplification on pooled D. immitis genomic DNA and on pooled cDNA, nine ABC transporter genes including one pseudogene were characterized. Bioinformatic and phylogenetic analyses allowed identification of three P-glycoproteins (Pgps) (Dim-pgp-3 Dim-pgp-10, Dim-pgp-11), of two ABC-B half transporter genes (one ortholog of Cel-haf-4 and Cel-haf-9; and one ortholog of Cel-haf-1 and Cel-haf-3), of one ABC half transporter gene (ortholog of Cel-haf-5) that contained an ABC-C motif, and of one additional half transporter that would require functional study for characterization. The number of ABC-B transporter genes identified was lower than in Caenorhabditis elegans and Haemonchus contortus. Further studies are needed to understand their possible role in ML resistance in D. immitis. These ABC transporters constitute a base for ML resistance investigation in D. immitis and advance our understanding of the molecular biology of this parasite. Copyright © 2016. Published by Elsevier Ltd.

CD73 expression identifies a subset of IgM+ antigen-experienced cells with memory attributes that is T cell and CD40 signalling dependent.

PubMed

D'Souza, Lucas; Gupta, Sneh Lata; Bal, Vineeta; Rath, Satyajit; George, Anna

2017-12-01

B-cell memory was long characterized as isotype-switched, somatically mutated and germinal centre (GC)-derived. However, it is now clear that the memory pool is a complex mixture that includes unswitched and unmutated cells. Further, expression of CD73, CD80 and CD273 has allowed the categorization of B-cell memory into multiple subsets, with combinatorial expression of the markers increasing with GC progression, isotype-switching and acquisition of somatic mutations. We have extended these findings to determine whether these markers can be used to identify IgM memory phenotypically as arising from T-dependent versus T-independent responses. We report that CD73 expression identifies a subset of antigen-experienced IgM + cells that share attributes of functional B-cell memory. This subset is reduced in the spleens of T-cell-deficient and CD40-deficient mice and in mixed marrow chimeras made with mutant and wild-type marrow, the proportion of CD73 + IgM memory is restored in the T-cell-deficient donor compartment but not in the CD40-deficient donor compartment, indicating that CD40 ligation is involved in its generation. We also report that CD40 signalling supports optimal expression of CD73 on splenic T cells and age-associated B cells (ABCs), but not on other immune cells such as neutrophils, marginal zone B cells, peritoneal cavity B-1 B cells and regulatory T and B cells. Our data indicate that in addition to promoting GC-associated memory generation during B-cell differentiation, CD40-signalling can influence the composition of the unswitched memory B-cell pool. They also raise the possibility that a fraction of ABCs may represent T-cell-dependent IgM memory. © 2017 John Wiley & Sons Ltd.

Three-dimensional graphdiyne as a topological nodal-line semimetal

NASA Astrophysics Data System (ADS)

Nomura, Takafumi; Habe, Tetsuro; Sakamoto, Ryota; Koshino, Mikito

2018-05-01

We study the electronic band structure of three-dimensional ABC-stacked (rhombohedral) graphdiyne, which is a new planar carbon allotrope recently fabricated. Using first-principles calculation, we show that the system is a nodal-line semimetal, in which the conduction band and valence band cross at a closed ring in the momentum space. We derive the minimum tight-binding model and the low-energy effective Hamiltonian in a 4 ×4 matrix form. The nodal line is protected by a nontrivial winding number, and it ensures the existence of the topological surface state in a finite-thickness slab. The Fermi surface of the doped system exhibits a peculiar, self-intersecting hourglass structure, which is quite different from the torus or pipe shape in the previously proposed nodal semimetals. Despite its simple configuration, three-dimensional graphdiyne offers unique electronic properties distinct from any other carbon allotropes.

Homologues of the human multidrug resistance genes MRP and MDR contribute to heavy metal resistance in the soil nematode Caenorhabditis elegans.

PubMed Central

Broeks, A; Gerrard, B; Allikmets, R; Dean, M; Plasterk, R H

1996-01-01

Acquired resistance of mammalian cells to multiple chemotherapeutic drugs can result from enhanced expression of the multidrug resistance-associated protein (MRP), which belongs to the ABC transporter superfamily. ABC transporters play a role in the protection of organisms against exogenous toxins by cellular detoxification processes. We have identified four MRP homologues in the soil nematode Caenorhabditis elegans, and we have studied one member, mrp-1, in detail. Using an mrp::lacZ gene fusion, mrp-l expression was found in cells of the pharynx, the pharynx-intestinal valve and the anterior intestinal cells, the rectum-intestinal valve and the epithelial cells of the vulva. Targeted inactivation of mrp-l resulted in increased sensitivity to the heavy metal ions cadmium and arsenite, to which wild-type worms are highly tolerant. The most pronounced effect of the mrp-1 mutation is on the ability of animals to recover from temporary exposure to high concentrations of heavy metals. Nematodes were found to be hypersensitive to heavy metals when both the MRP homologue, mrp-1, and a member of the P-glycoprotein (Pgp) gene family, pgp-1, were deleted. We conclude that nematodes have multiple proteins, homologues of mammalian proteins involved in the cellular resistance to chemotherapeutic drugs, that protect them against heavy metals. Images PMID:8947035

Inhibition of multidrug resistance protein 1 (MRP1) improves chemotherapy drug response in primary and recurrent glioblastoma multiforme.

PubMed

Tivnan, Amanda; Zakaria, Zaitun; O'Leary, Caitrín; Kögel, Donat; Pokorny, Jenny L; Sarkaria, Jann N; Prehn, Jochen H M

2015-01-01

Glioblastoma multiforme (GBM) is a highly aggressive brain cancer with extremely poor prognostic outcome despite intensive treatment. All chemotherapeutic agents currently used have no greater than 30-40% response rate, many fall into the range of 10-20%, with delivery across the blood brain barrier (BBB) or chemoresistance contributing to the extremely poor outcomes despite treatment. Increased expression of the multidrug resistance protein 1(MRP1) in high grade glioma, and it's role in BBB active transport, highlights this member of the ABC transporter family as a target for improving drug responses in GBM. In this study we show that small molecule inhibitors and gene silencing of MRP1 had a significant effect on GBM cell response to temozolomide (150 μM), vincristine (100 nM), and etoposide (2 μM). Pre-treatment with Reversan (inhibitor of MRP1 and P-glycoprotein) led to a significantly improved response to cell death in the presence of all three chemotherapeutics, in both primary and recurrent GBM cells. The presence of MK571 (inhibitor of MRP1 and multidrug resistance protein 4 (MRP4) led to an enhanced effect of vincristine and etoposide in reducing cell viability over a 72 h period. Specific MRP1 inhibition led to a significant increase in vincristine and etoposide-induced cell death in all three cell lines assessed. Treatment with MK571, or specific MRP1 knockdown, did not have any effect on temozolomide drug response in these cells. These findings have significant implications in providing researchers an opportunity to improve currently used chemotherapeutics for the initial treatment of primary GBM, and improved treatment for recurrent GBM patients.

Application of the Approximate Bayesian Computation methods in the stochastic estimation of atmospheric contamination parameters for mobile sources

NASA Astrophysics Data System (ADS)

Kopka, Piotr; Wawrzynczak, Anna; Borysiewicz, Mieczyslaw

2016-11-01

In this paper the Bayesian methodology, known as Approximate Bayesian Computation (ABC), is applied to the problem of the atmospheric contamination source identification. The algorithm input data are on-line arriving concentrations of the released substance registered by the distributed sensors network. This paper presents the Sequential ABC algorithm in detail and tests its efficiency in estimation of probabilistic distributions of atmospheric release parameters of a mobile contamination source. The developed algorithms are tested using the data from Over-Land Atmospheric Diffusion (OLAD) field tracer experiment. The paper demonstrates estimation of seven parameters characterizing the contamination source, i.e.: contamination source starting position (x,y), the direction of the motion of the source (d), its velocity (v), release rate (q), start time of release (ts) and its duration (td). The online-arriving new concentrations dynamically update the probability distributions of search parameters. The atmospheric dispersion Second-order Closure Integrated PUFF (SCIPUFF) Model is used as the forward model to predict the concentrations at the sensors locations.

Syntrophomonas wolfei Uses an NADH-Dependent, Ferredoxin-Independent [FeFe]-Hydrogenase To Reoxidize NADH

PubMed Central

Losey, Nathaniel A.; Mus, Florence; Peters, John W.; Le, Huynh M.

2017-01-01

ABSTRACT Syntrophomonas wolfei syntrophically oxidizes short-chain fatty acids (four to eight carbons in length) when grown in coculture with a hydrogen- and/or formate-using methanogen. The oxidation of 3-hydroxybutyryl-coenzyme A (CoA), formed during butyrate metabolism, results in the production of NADH. The enzyme systems involved in NADH reoxidation in S. wolfei are not well understood. The genome of S. wolfei contains a multimeric [FeFe]-hydrogenase that may be a mechanism for NADH reoxidation. The S. wolfei genes for the multimeric [FeFe]-hydrogenase (hyd1ABC; SWOL_RS05165, SWOL_RS05170, SWOL_RS05175) and [FeFe]-hydrogenase maturation proteins (SWOL_RS05180, SWOL_RS05190, SWOL_RS01625) were coexpressed in Escherichia coli, and the recombinant Hyd1ABC was purified and characterized. The purified recombinant Hyd1ABC was a heterotrimer with an αβγ configuration and a molecular mass of 115 kDa. Hyd1ABC contained 29.2 ± 1.49 mol of Fe and 0.7 mol of flavin mononucleotide (FMN) per mole enzyme. The purified, recombinant Hyd1ABC reduced NAD+ and oxidized NADH without the presence of ferredoxin. The HydB subunit of the S. wolfei multimeric [FeFe]-hydrogenase lacks two iron-sulfur centers that are present in known confurcating NADH- and ferredoxin-dependent [FeFe]-hydrogenases. Hyd1ABC is a NADH-dependent hydrogenase that produces hydrogen from NADH without the need of reduced ferredoxin, which differs from confurcating [FeFe]-hydrogenases. Hyd1ABC provides a mechanism by which S. wolfei can reoxidize NADH produced during syntrophic butyrate oxidation when low hydrogen partial pressures are maintained by a hydrogen-consuming microorganism. IMPORTANCE Our work provides mechanistic understanding of the obligate metabolic coupling that occurs between hydrogen-producing fatty and aromatic acid-degrading microorganisms and their hydrogen-consuming partners in the process called syntrophy (feeding together). The multimeric [FeFe]-hydrogenase used NADH without the involvement of reduced ferredoxin. The multimeric [FeFe]-hydrogenase would produce hydrogen from NADH only when hydrogen concentrations were low. Hydrogen production from NADH by Syntrophomonas wolfei would likely cease before any detectable amount of cell growth occurred. Thus, continual hydrogen production requires the presence of a hydrogen-consuming partner to keep hydrogen concentrations low and explains, in part, the obligate requirement that S. wolfei has for a hydrogen-consuming partner organism during growth on butyrate. We have successfully expressed genes encoding a multimeric [FeFe]-hydrogenase in E. coli, demonstrating that such an approach can be advantageous to characterize complex redox proteins from difficult-to-culture microorganisms. PMID:28802265

Long-term efficacy and safety of rilpivirine plus abacavir and lamivudine in HIV-1 infected patients with undetectable viral load.

PubMed

Galizzi, Nadia; Galli, Laura; Poli, Andrea; Gianotti, Nicola; Carini, Elisabetta; Bigoloni, Alba; Tambussi, Giuseppe; Nozza, Silvia; Lazzarin, Adriano; Castagna, Antonella; Mancusi, Daniela; Termini, Roberta

2018-01-01

A regimen with rilpivirine (RPV), abacavir (ABC) and lamivudine (3TC) is simple and may allow the sparing of tenofovir and protease inhibitors. However, data on use of this combination as a strategy of switch are limited. Aims of the study were to assess the long-term efficacy and safety of this regimen. Retrospective study on HIV-1 infected patients followed at the Infectious Disease Department of the San Raffaele Scientific Institute, HBsAg-negative, HLA B5701-negative, with no documented resistance to RPV, ABC and 3TC, with HIV-RNA<50 copies/mL who started RPV plus ABC/3TC from March 2013 to September 2015. The primary outcome was durability [no treatment failure (TF)]. Secondary objectives were to evaluate changes in immunological, metabolic and other safety parameters. TF was defined as the occurrence of virological failure (VF, 2 consecutive values >50 copies/mL) or discontinuation of any drug in the regimen for any reason. Patients' follow-up accrued from the date of RPV plus ABC/3TC initiation to the date of TF (VF or discontinuation of any drug in the regimen) or to the date of last available visit. Time to TF was evaluated by use of the Kaplan-Meier curves. Mixed linear models were applied to evaluate changes in immunological, metabolic and other safety parameters. In this analysis, 100 patients starting RPV plus ABC/3TC were included. By 12, 24 and 36 months after switching to RPV plus ABC/3TC, the proportions of individuals without TF were 88% [95% confidence interval (CI): 79%-93%], 82% (95% CI:73%-89%) and 78% (95% CI:68%-86%), respectively. Time to TF was not significantly influenced by CD4+ nadir (≤200 vs >200 cells/μl; log-rank test: p = 0.311) or pre-ART viral load (<100000 vs ≥100000 copies/mL; log-rank test: p = 0.574) or the type of previous antiretroviral regimen (PI+2NRTIs vs NNRTI+2NRTIs vs Other; log-rank test: p = 0.942). Over a median follow-up of 2.9 years (IQR: 1.9-3.5), 26 subjects discontinued the treatment [10 due to toxicity, 7 for interactions with other drugs, 3 due to cardiovascular risk concern, 2 due to single viral blip, 1 due to VF, 1 for asthma, 1 patient's decision, 1 due to enrolment in a study protocol]. In this retrospective study, long-term use of RPV plus ABC/3TC regimen is effective and safe. Efficacy of this regimen was not found to be affected by low CD4+ nadir or high pre-ART viral load.

Epstein-Barr virus latent gene sequences as geographical markers of viral origin: unique EBNA3 gene signatures identify Japanese viruses as distinct members of the Asian virus family.

PubMed

Sawada, Akihisa; Croom-Carter, Deborah; Kondo, Osamu; Yasui, Masahiro; Koyama-Sato, Maho; Inoue, Masami; Kawa, Keisei; Rickinson, Alan B; Tierney, Rosemary J

2011-05-01

Polymorphisms in Epstein-Barr virus (EBV) latent genes can identify virus strains from different human populations and individual strains within a population. An Asian EBV signature has been defined almost exclusively from Chinese viruses, with little information from other Asian countries. Here we sequenced polymorphic regions of the EBNA1, 2, 3A, 3B, 3C and LMP1 genes of 31 Japanese strains from control donors and EBV-associated T/NK-cell lymphoproliferative disease (T/NK-LPD) patients. Though identical to Chinese strains in their dominant EBNA1 and LMP1 alleles, Japanese viruses were subtly different at other loci. Thus, while Chinese viruses mainly fall into two families with strongly linked 'Wu' or 'Li' alleles at EBNA2 and EBNA3A/B/C, Japanese viruses all have the consensus Wu EBNA2 allele but fall into two families at EBNA3A/B/C. One family has variant Li-like sequences at EBNA3A and 3B and the consensus Li sequence at EBNA3C; the other family has variant Wu-like sequences at EBNA3A, variants of a low frequency Chinese allele 'Sp' at EBNA3B and a consensus Sp sequence at EBNA3C. Thus, EBNA3A/B/C allelotypes clearly distinguish Japanese from Chinese strains. Interestingly, most Japanese viruses also lack those immune-escape mutations in the HLA-A11 epitope-encoding region of EBNA3B that are so characteristic of viruses from the highly A11-positive Chinese population. Control donor-derived and T/NK-LPD-derived strains were similarly distributed across allelotypes and, by using allelic polymorphisms to track virus strains in patients pre- and post-haematopoietic stem-cell transplant, we show that a single strain can induce both T/NK-LPD and B-cell-lymphoproliferative disease in the same patient.

Biological and Clinical Relevance of Associated Genomic Alterations in MYD88 L265P and non-L265P-Mutated Diffuse Large B-Cell Lymphoma: Analysis of 361 Cases.

PubMed

Dubois, Sydney; Viailly, Pierre-Julien; Bohers, Elodie; Bertrand, Philippe; Ruminy, Philippe; Marchand, Vinciane; Maingonnat, Catherine; Mareschal, Sylvain; Picquenot, Jean-Michel; Penther, Dominique; Jais, Jean-Philippe; Tesson, Bruno; Peyrouze, Pauline; Figeac, Martin; Desmots, Fabienne; Fest, Thierry; Haioun, Corinne; Lamy, Thierry; Copie-Bergman, Christiane; Fabiani, Bettina; Delarue, Richard; Peyrade, Frédéric; André, Marc; Ketterer, Nicolas; Leroy, Karen; Salles, Gilles; Molina, Thierry J; Tilly, Hervé; Jardin, Fabrice

2017-05-01

Purpose: MYD88 mutations, notably the recurrent gain-of-function L265P variant, are a distinguishing feature of activated B-cell like (ABC) diffuse large B-cell lymphoma (DLBCL), leading to constitutive NFκB pathway activation. The aim of this study was to examine the distinct genomic profiles of MYD88 -mutant DLBCL, notably according to the presence of the L265P or other non-L265P MYD88 variants. Experimental Design: A cohort of 361 DLBCL cases (94 MYD88 mutant and 267 MYD88 wild-type) was submitted to next-generation sequencing (NGS) focusing on 34 genes to analyze associated mutations and copy number variations, as well as gene expression profiling, and clinical and prognostic analyses. Results: Importantly, we highlighted different genomic profiles for MYD88 L265P and MYD88 non-L265P-mutant DLBCL, shedding light on their divergent backgrounds. Clustering analysis also segregated subgroups according to associated genetic alterations among patients with the same MYD88 mutation. We showed that associated CD79B and MYD88 L265P mutations act synergistically to increase NFκB pathway activation, although the majority of MYD88 L265P-mutant cases harbors downstream NFκB alterations, which can predict BTK inhibitor resistance. Finally, although the MYD88 L265P variant was not an independent prognostic factor in ABC DLBCL, associated CD79B mutations significantly improved the survival of MYD88 L265P-mutant ABC DLBCL in our cohort. Conclusions: This study highlights the relative heterogeneity of MYD88 -mutant DLBCL, adding to the field's knowledge of the theranostic importance of MYD88 mutations, but also of associated alterations, emphasizing the usefulness of genomic profiling to best stratify patients for targeted therapy. Clin Cancer Res; 23(9); 2232-44. ©2016 AACR . ©2016 American Association for Cancer Research.

Approximate Bayesian computation in large-scale structure: constraining the galaxy-halo connection

NASA Astrophysics Data System (ADS)

Hahn, ChangHoon; Vakili, Mohammadjavad; Walsh, Kilian; Hearin, Andrew P.; Hogg, David W.; Campbell, Duncan

2017-08-01

Standard approaches to Bayesian parameter inference in large-scale structure assume a Gaussian functional form (chi-squared form) for the likelihood. This assumption, in detail, cannot be correct. Likelihood free inferences such as approximate Bayesian computation (ABC) relax these restrictions and make inference possible without making any assumptions on the likelihood. Instead ABC relies on a forward generative model of the data and a metric for measuring the distance between the model and data. In this work, we demonstrate that ABC is feasible for LSS parameter inference by using it to constrain parameters of the halo occupation distribution (HOD) model for populating dark matter haloes with galaxies. Using specific implementation of ABC supplemented with population Monte Carlo importance sampling, a generative forward model using HOD and a distance metric based on galaxy number density, two-point correlation function and galaxy group multiplicity function, we constrain the HOD parameters of mock observation generated from selected 'true' HOD parameters. The parameter constraints we obtain from ABC are consistent with the 'true' HOD parameters, demonstrating that ABC can be reliably used for parameter inference in LSS. Furthermore, we compare our ABC constraints to constraints we obtain using a pseudo-likelihood function of Gaussian form with MCMC and find consistent HOD parameter constraints. Ultimately, our results suggest that ABC can and should be applied in parameter inference for LSS analyses.

The minimal-ABC trees with B1-branches.

PubMed

Dimitrov, Darko; Du, Zhibin; Fonseca, Carlos M da

2018-01-01

The atom-bond connectivity index (or, for short, ABC index) is a molecular structure descriptor bridging chemistry to graph theory. It is probably the most studied topological index among all numerical parameters of a graph that characterize its topology. For a given graph G = (V, E), the ABC index of G is defined as [Formula: see text], where di denotes the degree of the vertex i, and ij is the edge incident to the vertices i and j. A combination of physicochemical and the ABC index properties are commonly used to foresee the bioactivity of different chemical composites. Additionally, the applicability of the ABC index in chemical thermodynamics and other areas of chemistry, such as in dendrimer nanostars, benzenoid systems, fluoranthene congeners, and phenylenes is well studied in the literature. While finding of the graphs with the greatest ABC-value is a straightforward assignment, the characterization of the tree(s) with minimal ABC index is a problem largely open and has recently given rise to numerous studies and conjectures. A B1-branch of a graph is a pendent path of order 2. In this paper, we provide an important step forward to the full characterization of these minimal trees. Namely, we show that a minimal-ABC tree contains neither 4 nor 3 B1-branches. The case when the number of B1-branches is 2 is also considered.

Use of an autologous bioengineered composite skin in extensive burns: Clinical and functional outcomes. A multicentric study.

PubMed

Gómez, C; Galán, J M; Torrero, V; Ferreiro, I; Pérez, D; Palao, R; Martínez, E; Llames, S; Meana, A; Holguín, P

2011-06-01

We report clinical and functional outcomes obtained after application of an autologous bioengineered composite skin (ABCS) produced in a single Spanish tissue-engineering unit. Twenty-five burned patients treated with ABCS from 1999 to 2007 in five burn centres were included in the study. Mean age was 29 years (SD 11), with mean total body surface area (TBSA) burned being 74% (SD 17) and mean full-thickness injury of 61% (SD 19) of TBSA. The mean area initially engrafted with ABCS was 24% (SD 13) of TBSA, with a final take of 49% (SD 30, range 0-100%). ABCS achieved permanent coverage of a mean of 11% (SD 8) of TBSA. In subset analyses, lack of pre- and post-application wound bed infection and lack of serious acute systemic complications at the time of engraftment were significantly associated with better ABCS take. Final take obtained with ABCS could be improved with the use of non-cytotoxic topical antibiotics following engraftment. The use of plasma to prepare ABCS reduces production costs: cost-effectiveness ratio is not a limitation for its use. In terms of patient satisfaction, cosmetic/functional outcomes (general appearance, texture, flexibility, sensitivity and colour) of ABCS and split-thickness autografts are not different statistically. Copyright © 2010 Elsevier Ltd and ISBI. All rights reserved.

The ABC and AUSSAT.

ERIC Educational Resources Information Center

McGarritty, Ian

1985-01-01

Discusses the Australian Broadcasting Corporation's (ABC) utilization of the AUSSAT telecommunications satellite to extend its television and radio transmission range to reach remote Australian audiences; the satellite's program gathering and interchange capabilities; and ABC's generation of other benefits to offset cost of satellite services.…

Activities-specific balance confidence scale for predicting future falls in Indian older adults.

PubMed

Moiz, Jamal Ali; Bansal, Vishal; Noohu, Majumi M; Gaur, Shailendra Nath; Hussain, Mohammad Ejaz; Anwer, Shahnawaz; Alghadir, Ahmad

2017-01-01

Activities-specific balance confidence (ABC) scale is a subjective measure of confidence in performing various ambulatory activities without falling or experiencing a sense of unsteadiness. This study aimed to examine the ability of the Hindi version of the ABC scale (ABC-H scale) to discriminate between fallers and non-fallers and to examine its predictive validity for prospective falls. This was a prospective cohort study. A total of 125 community-dwelling older adults (88 were men) completed the ABC-H scale. The occurrence of falls over the follow-up period of 12 months was recorded. Discriminative validity was analyzed by comparing the total ABC-H scale scores between the faller and non-faller groups. A receiver operating characteristic curve analysis and a logistic regression analysis were used to examine the predictive accuracy of the ABC-H scale. The mean ABC-H scale score of the faller group was significantly lower than that of the non-faller group (52.6±8.1 vs 73.1±12.2; P <0.001). The optimal cutoff value for distinguishing faller and non-faller adults was ≤58.13. The sensitivity, specificity, area under the curve, and positive and negative likelihood ratios of the cutoff score were 86.3%, 87.3%, 0.91 ( P <0.001), 6.84, and 0.16, respectively. The percentage test accuracy and false-positive and false-negative rates were 86.87%, 12.2%, and 13.6%, respectively. A dichotomized total ABC-H scale score of ≤58.13% (adjusted odds ratio =0.032, 95% confidence interval =0.004-0.25, P =0.001) was significantly related with future falls. The ABC-H scores were significantly and independently related with future falls in the community-dwelling Indian older adults. The ability of the ABC-H scale to predict future falls was adequate with high sensitivity and specificity values.

IMG-ABC: A Knowledge Base To Fuel Discovery of Biosynthetic Gene Clusters and Novel Secondary Metabolites.

PubMed

Hadjithomas, Michalis; Chen, I-Min Amy; Chu, Ken; Ratner, Anna; Palaniappan, Krishna; Szeto, Ernest; Huang, Jinghua; Reddy, T B K; Cimermančič, Peter; Fischbach, Michael A; Ivanova, Natalia N; Markowitz, Victor M; Kyrpides, Nikos C; Pati, Amrita

2015-07-14

In the discovery of secondary metabolites, analysis of sequence data is a promising exploration path that remains largely underutilized due to the lack of computational platforms that enable such a systematic approach on a large scale. In this work, we present IMG-ABC (https://img.jgi.doe.gov/abc), an atlas of biosynthetic gene clusters within the Integrated Microbial Genomes (IMG) system, which is aimed at harnessing the power of "big" genomic data for discovering small molecules. IMG-ABC relies on IMG's comprehensive integrated structural and functional genomic data for the analysis of biosynthetic gene clusters (BCs) and associated secondary metabolites (SMs). SMs and BCs serve as the two main classes of objects in IMG-ABC, each with a rich collection of attributes. A unique feature of IMG-ABC is the incorporation of both experimentally validated and computationally predicted BCs in genomes as well as metagenomes, thus identifying BCs in uncultured populations and rare taxa. We demonstrate the strength of IMG-ABC's focused integrated analysis tools in enabling the exploration of microbial secondary metabolism on a global scale, through the discovery of phenazine-producing clusters for the first time in Alphaproteobacteria. IMG-ABC strives to fill the long-existent void of resources for computational exploration of the secondary metabolism universe; its underlying scalable framework enables traversal of uncovered phylogenetic and chemical structure space, serving as a doorway to a new era in the discovery of novel molecules. IMG-ABC is the largest publicly available database of predicted and experimental biosynthetic gene clusters and the secondary metabolites they produce. The system also includes powerful search and analysis tools that are integrated with IMG's extensive genomic/metagenomic data and analysis tool kits. As new research on biosynthetic gene clusters and secondary metabolites is published and more genomes are sequenced, IMG-ABC will continue to expand, with the goal of becoming an essential component of any bioinformatic exploration of the secondary metabolism world. Copyright © 2015 Hadjithomas et al.

Interaction of ABC multidrug transporters with anticancer protein kinase inhibitors: substrates and/or inhibitors?

PubMed

Hegedus, Csilla; Ozvegy-Laczka, Csilla; Szakács, Gergely; Sarkadi, Balázs

2009-05-01

Protein kinase inhibitors (PKI) are becoming key agents in modern cancer chemotherapy, and combination of PKIs with classical chemotherapeutic drugs may help to overcome currently untreatable metastatic cancers. Since chemotherapy resistance is a recurrent problem, mechanisms of resistance should be clarified in order to help further drug development. Here we suggest that in addition to PKI resistance based on altered target structures, the active removal of these therapeutic agents by the MDR-ABC transporters should also be considered as a major cause of clinical resistance. We discuss the occurring systemic and cellular mechanisms, which may hamper PKI efficiency, and document the role of selected MDR-ABC transporters in these phenomena through their interactions with these anticancer agents. Moreover, we suggest that PKI interactions with ABC transporters may modulate overall drug metabolism, including the fate of diverse, chemically or target-wise unrelated drugs. These effects are based on multiple forms of MDR-ABC transporter interaction with PKIs, as these compounds may be both substrates and/or inhibitors of an ABC transporter. We propose that these interactions should be carefully considered in clinical application, and a combined MDR-ABC transporter and PKI effect may bring a major advantage in future drug development.

Laboratory investigation of grouted coupler connection details for ABC bridge projects.

DOT National Transportation Integrated Search

2015-08-01

With an ever increasing desire to utilize accelerated bridge construction (ABC) techniques, it is becoming critical that bridge : designers and contractors have confidence in typical details. The Keg Creek Bridge on US 6 in Iowa was a recent ABC exam...

The ABC protein turned chloride channel whose failure causes cystic fibrosis

NASA Astrophysics Data System (ADS)

Gadsby, David C.; Vergani, Paola; Csanády, László

2006-03-01

CFTR chloride channels are encoded by the gene mutated in patients with cystic fibrosis. These channels belong to the superfamily of ABC transporter ATPases. ATP-driven conformational changes, which in other ABC proteins fuel uphill substrate transport across cellular membranes, in CFTR open and close a gate to allow transmembrane flow of anions down their electrochemical gradient. New structural and biochemical information from prokaryotic ABC proteins and functional information from CFTR channels has led to a unifying mechanism explaining those ATP-driven conformational changes.

CREATING AN IPHONE APPLICATION FOR COLLECTING CONTINUOUS ABC DATA

PubMed Central

Whiting, Seth W; Dixon, Mark R

2012-01-01

This paper provides an overview and task analysis for creating a continuous ABC data-collection application using Xcode on a Mac computer. Behavior analysts can program an ABC data collection system, complete with a customized list of target clients, antecedents, behaviors, and consequences to be recorded, and have the data automatically sent to an e-mail account after observations have concluded. Further suggestions are provided to customize the ABC data- collection system for individual preferences and clinical needs. PMID:23060682

Creating an iPhone application for collecting continuous ABC data.

PubMed

Whiting, Seth W; Dixon, Mark R

2012-01-01

This paper provides an overview and task analysis for creating a continuous ABC data-collection application using Xcode on a Mac computer. Behavior analysts can program an ABC data collection system, complete with a customized list of target clients, antecedents, behaviors, and consequences to be recorded, and have the data automatically sent to an e-mail account after observations have concluded. Further suggestions are provided to customize the ABC data- collection system for individual preferences and clinical needs.

ABCC1, an ATP Binding Cassette Protein from Grape Berry, Transports Anthocyanidin 3-O-Glucosides[W][OA

PubMed Central

Francisco, Rita Maria; Regalado, Ana; Ageorges, Agnès; Burla, Bo J.; Bassin, Barbara; Eisenach, Cornelia; Zarrouk, Olfa; Vialet, Sandrine; Marlin, Thérèse; Chaves, Maria Manuela; Martinoia, Enrico; Nagy, Réka

2013-01-01

Accumulation of anthocyanins in the exocarp of red grapevine (Vitis vinifera) cultivars is one of several events that characterize the onset of grape berry ripening (véraison). Despite our thorough understanding of anthocyanin biosynthesis and regulation, little is known about the molecular aspects of their transport. The participation of ATP binding cassette (ABC) proteins in vacuolar anthocyanin transport has long been a matter of debate. Here, we present biochemical evidence that an ABC protein, ABCC1, localizes to the tonoplast and is involved in the transport of glucosylated anthocyanidins. ABCC1 is expressed in the exocarp throughout berry development and ripening, with a significant increase at véraison (i.e., the onset of ripening). Transport experiments using microsomes isolated from ABCC1-expressing yeast cells showed that ABCC1 transports malvidin 3-O-glucoside. The transport strictly depends on the presence of GSH, which is cotransported with the anthocyanins and is sensitive to inhibitors of ABC proteins. By exposing anthocyanin-producing grapevine root cultures to buthionine sulphoximine, which reduced GSH levels, a decrease in anthocyanin concentration is observed. In conclusion, we provide evidence that ABCC1 acts as an anthocyanin transporter that depends on GSH without the formation of an anthocyanin-GSH conjugate. PMID:23723325

Poor concordance among nine immunohistochemistry classifiers of cell-of-origin for diffuse large B-cell lymphoma: implications for therapeutic strategies.

PubMed

Coutinho, Rita; Clear, Andrew James; Owen, Andrew; Wilson, Andrew; Matthews, Janet; Lee, Abigail; Alvarez, Rute; Gomes da Silva, Maria; Cabeçadas, José; Calaminici, Maria; Gribben, John G

2013-12-15

The opportunity to improve therapeutic choices on the basis of molecular features of the tumor cells is on the horizon in diffuse large B-cell lymphoma (DLBCL). Agents such as bortezomib exhibit selective activity against the poor outcome activated B-cell type (ABC) DLBCL. In order for targeted therapies to succeed in this disease, robust strategies that segregate patients into molecular groups with high reliability are needed. Although molecular studies are considered gold standard, several immunohistochemistry (IHC) algorithms have been published that claim to be able to stratify patients according to their cell-of-origin and to be relevant for patient outcome. However, results are poorly reproducible by independent groups. We investigated nine IHC algorithms for molecular classification in a dataset of DLBCL diagnostic biopsies, incorporating immunostaining for CD10, BCL6, BCL2, MUM1, FOXP1, GCET1, and LMO2. IHC profiles were assessed and agreed among three expert observers. A consensus matrix based on all scoring combinations and the number of subjects for each combination allowed us to assess reliability. The survival impact of individual markers and classifiers was evaluated using Kaplan-Meier curves and the log-rank test. The concordance in patient's classification across the different algorithms was low. Only 4% of the tumors have been classified as germinal center B-cell type (GCB) and 21% as ABC/non-GCB by all methods. None of the algorithms provided prognostic information in the R-CHOP (rituximab plus cyclophosphamide-adriamycin-vincristine-prednisone)-treated cohort. Further work is required to standardize IHC algorithms for DLBCL cell-of-origin classification for these to be considered reliable alternatives to molecular-based methods to be used for clinical decisions. ©2013 AACR.

Mapping heterogeneity in patient-derived melanoma cultures by single-cell RNA-seq

PubMed Central

Loeffler-Wirth, Henry; Hopp, Lydia; Schadendorf, Dirk; Schartl, Manfred; Anderegg, Ulf; Camp, Gray; Treutlein, Barbara; Binder, Hans; Kunz, Manfred

2017-01-01

Recent technological advances in single-cell genomics make it possible to analyze cellular heterogeneity of tumor samples. Here, we applied single-cell RNA-seq to measure the transcriptomes of 307 single cells cultured from three biopsies of three different patients with a BRAF/NRAS wild type, BRAF mutant/NRAS wild type and BRAF wild type/NRAS mutant melanoma metastasis, respectively. Analysis based on self-organizing maps identified sub-populations defined by multiple gene expression modules involved in proliferation, oxidative phosphorylation, pigmentation and cellular stroma. Gene expression modules had prognostic relevance when compared with gene expression data from published melanoma samples and patient survival data. We surveyed kinome expression patterns across sub-populations of the BRAF/NRAS wild type sample and found that CDK4 and CDK2 were consistently highly expressed in the majority of cells, suggesting that these kinases might be involved in melanoma progression. Treatment of cells with the CDK4 inhibitor palbociclib restricted cell proliferation to a similar, and in some cases greater, extent than MAPK inhibitors. Finally, we identified a low abundant sub-population in this sample that highly expressed a module containing ABC transporter ABCB5, surface markers CD271 and CD133, and multiple aldehyde dehydrogenases (ALDHs). Patient-derived cultures of the BRAF mutant/NRAS wild type and BRAF wild type/NRAS mutant metastases showed more homogeneous single-cell gene expression patterns with gene expression modules for proliferation and ABC transporters. Taken together, our results describe an intertumor and intratumor heterogeneity in melanoma short-term cultures which might be relevant for patient survival, and suggest promising targets for new treatment approaches in melanoma therapy. PMID:27903987

ArgR is an essential local transcriptional regulator of the arcABC operon in Streptococcus suis and is crucial for biological fitness in an acidic environment.

PubMed

Fulde, Marcus; Willenborg, Joerg; de Greeff, Astrid; Benga, Laurentiu; Smith, Hilde E; Valentin-Weigand, Peter; Goethe, Ralph

2011-02-01

Streptococcus suis is one of the most important pathogens in pigs and can also cause severe infections in humans. Despite its clinical relevance, very little is known about the factors that contribute to its virulence. Recently, we identified a new putative virulence factor in S. suis, the arginine deiminase system (ADS), an arginine catabolic enzyme system encoded by the arcABC operon, which enables S. suis to survive in an acidic environment. In this study, we focused on ArgR, an ADS-associated regulator belonging to the ArgR/AhrC arginine repressor family. Using an argR knockout strain we were able to show that ArgR is essential for arcABC operon expression and necessary for the biological fitness of S. suis. By cDNA expression microarray analyses and quantitative real-time RT-PCR we found that the arcABC operon is the only gene cluster regulated by ArgR, which is in contrast to the situation in many other bacteria. Reporter gene analysis with gfp under the control of the arcABC promoter demonstrated that ArgR is able to activate the arcABC promoter. Electrophoretic mobility shift assays with fragments of the arcABC promoter and recombinant ArgR, and chromatin immunoprecipitation with antibodies directed against ArgR, revealed that ArgR interacts with the arcABC promoter in vitro and in vivo by binding to a region from -147 to -72 bp upstream of the transcriptional start point. Overall, our results show that in S. suis, ArgR is an essential, system-specific transcriptional regulator of the ADS that interacts directly with the arcABC promoter in vivo.

Transcriptome-Based Identification of ABC Transporters in the Western Tarnished Plant Bug Lygus hesperus

PubMed Central

Hull, J. Joe; Chaney, Kendrick; Geib, Scott M.; Fabrick, Jeffrey A.; Brent, Colin S.; Walsh, Douglas; Lavine, Laura Corley

2014-01-01

ATP-binding cassette (ABC) transporters are a large superfamily of proteins that mediate diverse physiological functions by coupling ATP hydrolysis with substrate transport across lipid membranes. In insects, these proteins play roles in metabolism, development, eye pigmentation, and xenobiotic clearance. While ABC transporters have been extensively studied in vertebrates, less is known concerning this superfamily in insects, particularly hemipteran pests. We used RNA-Seq transcriptome sequencing to identify 65 putative ABC transporter sequences (including 36 full-length sequences) from the eight ABC subfamilies in the western tarnished plant bug (Lygus hesperus), a polyphagous agricultural pest. Phylogenetic analyses revealed clear orthologous relationships with ABC transporters linked to insecticide/xenobiotic clearance and indicated lineage specific expansion of the L. hesperus ABCG and ABCH subfamilies. The transcriptional profile of 13 LhABCs representative of the ABCA, ABCB, ABCC, ABCG, and ABCH subfamilies was examined across L. hesperus development and within sex-specific adult tissues. All of the transcripts were amplified from both reproductively immature and mature adults and all but LhABCA8 were expressed to some degree in eggs. Expression of LhABCA8 was spatially localized to the testis and temporally timed with male reproductive development, suggesting a potential role in sexual maturation and/or spermatozoa protection. Elevated expression of LhABCC5 in Malpighian tubules suggests a possible role in xenobiotic clearance. Our results provide the first transcriptome-wide analysis of ABC transporters in an agriculturally important hemipteran pest and, because ABC transporters are known to be important mediators of insecticidal resistance, will provide the basis for future biochemical and toxicological studies on the role of this protein family in insecticide resistance in Lygus species. PMID:25401762

SPECT Analysis of Cardiac Perfusion Changes After Whole-Breast/Chest Wall Radiation Therapy With or Without Active Breathing Coordinator: Results of a Randomized Phase 3 Trial

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zellars, Richard, E-mail: zellari@jhmi.edu; Bravo, Paco E.; Tryggestad, Erik

2014-03-15

Purpose: Cardiac muscle perfusion, as determined by single-photon emission computed tomography (SPECT), decreases after breast and/or chest wall (BCW) irradiation. The active breathing coordinator (ABC) enables radiation delivery when the BCW is farther from the heart, thereby decreasing cardiac exposure. We hypothesized that ABC would prevent radiation-induced cardiac toxicity and conducted a randomized controlled trial evaluating myocardial perfusion changes after radiation for left-sided breast cancer with or without ABC. Methods and Materials: Stages I to III left breast cancer patients requiring adjuvant radiation therapy (XRT) were randomized to ABC or No-ABC. Myocardial perfusion was evaluated by SPECT scans (before andmore » 6 months after BCW radiation) using 2 methods: (1) fully automated quantitative polar mapping; and (2) semiquantitative visual assessment. The left ventricle was divided into 20 segments for the polar map and 17 segments for the visual method. Segments were grouped by anatomical rings (apical, mid, basal) or by coronary artery distribution. For the visual method, 2 nuclear medicine physicians, blinded to treatment groups, scored each segment's perfusion. Scores were analyzed with nonparametric tests and linear regression. Results: Between 2006 and 2010, 57 patients were enrolled and 43 were available for analysis. The cohorts were well matched. The apical and left anterior descending coronary artery segments had significant decreases in perfusion on SPECT scans in both ABC and No-ABC cohorts. In unadjusted and adjusted analyses, controlling for pretreatment perfusion score, age, and chemotherapy, ABC was not significantly associated with prevention of perfusion deficits. Conclusions: In this randomized controlled trial, ABC does not appear to prevent radiation-induced cardiac perfusion deficits.« less

Constitutive androstane receptor upregulates Abcb1 and Abcg2 at the blood-brain barrier after CITCO activation.

PubMed

Lemmen, Julia; Tozakidis, Iasson E P; Bele, Prachee; Galla, Hans-Joachim

2013-03-21

ATP-driven efflux transporters are considered to be the major hurdle in the treatment of central nervous system (CNS) diseases. Abcb1 (P-glycoprotein) and Abcg2 (breast cancer resistance protein/brain multidrug resistance protein) belong to the best known ABC-transporters. These ABC-transporters limit the permeability of the blood-brain barrier and protect the brain against toxic compounds in the blood but on the other hand they also reduce the efficacy of CNS pharmacotherapy. Even after 40 years of extensive research, the regulatory mechanisms of these efflux transporters are still not completely understood. To unravel the efflux transporter regulation, we analyzed the effect of the nuclear receptor CAR (constitutive androstane receptor) on the expression of Abcb1 and Abcg2 in primary cultures of porcine brain capillary endothelial cells (PBCEC). CAR is a xenobiotic-activated transcription factor, which is, like the other important nuclear receptor pregnane X receptor (PXR), highly expressed in barrier tissue and known to be a positive regulator of ABC-transporters. We demonstrate that activation of porcine CAR by the human CAR (hCAR) ligand CITCO (6-(4-chlorophenyl)-imidazo[2,1-b]thiazole-5-carbaldehyde) leads to an up-regulation of both transporters, whereas the mouse-specific CAR ligand TCPOBOP (1,4-bis-[2-(3,5-dichloropyridyloxy)]benzene) had no effect on transporter expression. The stimulation of PBCEC with CITCO caused a significant up-regulation of both efflux-transporters on RNA-level, protein level and transport level. Furthermore the additional application of a CAR inhibitor significantly decreased the transporter expression to control niveau. In conclusion our data prove CAR activation only by the human ligand CITCO leading to an increased ABC-transporter expression and transport activity. Copyright © 2013 Elsevier B.V. All rights reserved.

Yang-Mills theory and the ABC conjecture

NASA Astrophysics Data System (ADS)

He, Yang-Hui; Hu, Zhi; Probst, Malte; Read, James

2018-05-01

We establish a precise correspondence between the ABC Conjecture and 𝒩 = 4 super-Yang-Mills theory. This is achieved by combining three ingredients: (i) Elkies’ method of mapping ABC-triples to elliptic curves in his demonstration that ABC implies Mordell/Faltings; (ii) an explicit pair of elliptic curve and associated Belyi map given by Khadjavi-Scharaschkin; and (iii) the fact that the bipartite brane-tiling/dimer model for a gauge theory with toric moduli space is a particular dessin d’enfant in the sense of Grothendieck. We explore this correspondence for the highest quality ABC-triples as well as large samples of random triples. The conjecture itself is mapped to a statement about the fundamental domain of the toroidal compactification of the string realization of 𝒩 = 4 SYM.

Compact high order schemes with gradient-direction derivatives for absorbing boundary conditions

NASA Astrophysics Data System (ADS)

Gordon, Dan; Gordon, Rachel; Turkel, Eli

2015-09-01

We consider several compact high order absorbing boundary conditions (ABCs) for the Helmholtz equation in three dimensions. A technique called "the gradient method" (GM) for ABCs is also introduced and combined with the high order ABCs. GM is based on the principle of using directional derivatives in the direction of the wavefront propagation. The new ABCs are used together with the recently introduced compact sixth order finite difference scheme for variable wave numbers. Experiments on problems with known analytic solutions produced very accurate results, demonstrating the efficacy of the high order schemes, particularly when combined with GM. The new ABCs are then applied to the SEG/EAGE Salt model, showing the advantages of the new schemes.

Successful vitrification of human amnion-derived mesenchymal stem cells.

PubMed

Moon, Jeong Hee; Lee, Jung Ryeol; Jee, Byung Chul; Suh, Chang Suk; Kim, Seok Hyun; Lim, Hyun Jung; Kim, Hae Kwon

2008-08-01

A cryopreservation protocol for human amnion-derived mesenchymal stem cells (HAMs) is required because these cells cannot survive for long periods in culture. The aim of this study was to determine whether vitrification is a useful freezing method for storage of HAMs. HAMs were cryopreserved using vitrification method. The morphology and viability of thawed HAMs was evaluated by Trypan Blue staining. The expression of several embryonic stem cell (ESC) markers was evaluated using flow cytometry, RT-PCR and immunocytochemistry. Von Kossa, Oil Red O and Alcian Blue staining were used to asses the differentiation potential of thawed HAMs. The post-thawing viability of HAMs was 84.3 +/- 3.2% (Mean +/- SD, n = 10). The thawed HAMs showed morphological characteristics indistinguishable from the non-vitrified fresh HAMs. The expression of surface antigens (strong positive for CD44, CD49d, CD59, CD90, CD105 and HLA-ABC; weak positive for HLA-G; negative for CD31, CD34, CD45, CD106, CD117 and HLA-DR) and the expression of ESC markers [CK18, fibroblast growth factor-5, GATA-4, neural cell adhesion molecule, Nestin, Oct-4, stem cell factor, HLA-ABC, Vimentin, bone morphogenetic protein (BMP) 4, hepatocyte nuclear factor 4 alpha (HNF-4 alpha), Pax-6, alpha-fetoprotein, Brachyury, BMP-2, TRA-1-60, stage-specific embryonic antigen (SSEA-3, SSEA-4)] were maintained in the vitrified-thawed HAMs. The thawed HAMs retained ability to differentiate into osteoblasts, adipocytes and chondrocytes under appropriate culture conditions. Our results suggest that vitrification is a reliable and effective method for cryopreservation of HAMs.

The Cost of Library Services: Activity-Based Costing in an Australian Academic Library.

ERIC Educational Resources Information Center

Robinson, Peter; Ellis-Newman, Jennifer

1998-01-01

Explains activity-based costing (ABC), discusses the benefits of ABC to library managers, and describes the steps involved in implementing ABC in an Australian academic library. Discusses the budgeting process in universities, and considers benefits to the library. (Author/LRW)

Effect of SOS-induced levels of imuABC on spontaneous and damage-induced mutagenesis in Caulobacter crescentus.

PubMed

Alves, Ingrid R; Lima-Noronha, Marco A; Silva, Larissa G; Fernández-Silva, Frank S; Freitas, Aline Luiza D; Marques, Marilis V; Galhardo, Rodrigo S

2017-11-01

imuABC (imuAB dnaE2) genes are responsible for SOS-mutagenesis in Caulobacter crescentus and other bacterial species devoid of umuDC. In this work, we have constructed operator-constitutive mutants of the imuABC operon. We used this genetic tool to investigate the effect of SOS-induced levels of these genes upon both spontaneous and damage-induced mutagenesis. We showed that constitutive expression of imuABC does not increase spontaneous or damage-induced mutagenesis, nor increases cellular resistance to DNA-damaging agents. Nevertheless, the presence of the operator-constitutive mutation rescues mutagenesis in a recA background, indicating that imuABC are the only genes required at SOS-induced levels for translesion synthesis (TLS) in C. crescentus. Furthermore, these data also show that TLS mediated by ImuABC does not require RecA, unlike umuDC-dependent mutagenesis in E. coli. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of steam activation of biochar produced from a giant Miscanthus on copper sorption and toxicity.

PubMed

Shim, Taeyong; Yoo, Jisu; Ryu, Changkook; Park, Yong-Kwon; Jung, Jinho

2015-12-01

This study aims to evaluate the physiochemical properties, sorption characteristics, and toxicity effects of biochar (BC) produced from Miscanthus sacchariflorus via slow pyrolysis at 500°C and its steam activation product (ABC). Although BC has a much lower surface area than ABC (181 and 322m(2)g(-1), respectively), the Cu sorption capacities of BC and ABC are not significantly different (p>0.05). A two-compartment model successfully explains the sorption of BC and ABC as being dominated by fast and slow sorption processes, respectively. In addition, both BC and ABC efficiently eliminate the toxicity of Cu towards Daphnia magna. However, ABC itself induced acute toxicity to D. magna, which is possibly due to increased aromaticity upon steam activation. These findings suggest that activation of BC produced from M. sacchariflorus at a pyrolytic temperature of 500°C may not be appropriate in terms of Cu sorption and toxicity reduction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Inhibition of the Human ABC Efflux Transporters P-gp and ...

EPA Pesticide Factsheets

High body burdens of polybrominated diphenyl ethers (PBDEs) in infants and young children have led to increased concern over their potential impact on human development. PBDE exposure can alter the expression of genes involved in thyroid homeostasis, including those of ATP-binding cassette (ABC) transporters, which mediate cellular xenobiotic efflux. However, little information exists on how PBDEs interact with ABC transporters such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP). The purpose of this study was to evaluate the interactions of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) and its hydroxylated metabolite 6-OH-BDE-47 with P-gp and BCRP, using human MDR1- and BCRP-expressing membrane vesicles and stably transfected NIH-3T3-MDR1 and MDCK-BCRP cells. In P-gp membranes, BDE-47 did not affect P-gp activity; however, 6-OH-BDE-47 inhibited P-gp activity at low µM concentrations (IC50 = 11.7 µM). In BCRP membranes, BDE-47 inhibited BCRP activity; however, 6-OH-BDE-47 was a stronger inhibitor [IC50 = 45.9 µM (BDE-47) vs. IC50 = 9.4 µM (6-OH-BDE-47)]. Intracellular concentrations of known P-gp and BCRP substrates [(3H)-paclitaxel and (3H)-prazosin, respectively] were significantly higher (indicating less efflux) in NIH-3T3-MDR1 and MDCK-BCRP cells in the presence of 6-OH-BDE-47, but not BDE-47. Collectively, our results indicate that the BDE-47 metabolite 6-OH-BDE-47 is an inhibitor of both P-gp and BCRP efflux activity.

Flavone-resistant Leishmania donovani Overexpresses LdMRP2 Transporter in the Parasite and Activates Host MRP2 on Macrophages to Circumvent the Flavone-mediated Cell Death*

PubMed Central

Chowdhury, Sayan; Mukhopadhyay, Rupkatha; Saha, Sourav; Mishra, Amartya; Sengupta, Souvik; Roy, Syamal; Majumder, Hemanta K.

2014-01-01

In parasites, ATP-binding cassette (ABC) transporters represent an important family of proteins related to drug resistance and other biological activities. Resistance of leishmanial parasites to therapeutic drugs continues to escalate in developing countries, and in many instances, it is due to overexpressed ABC efflux pumps. Progressively adapted baicalein (BLN)-resistant parasites (pB25R) show overexpression of a novel ABC transporter, which was classified as ABCC2 or Leishmania donovani multidrug resistance protein 2 (LdMRP2). The protein is primarily localized in the flagellar pocket region and in internal vesicles. Overexpressed LdABCC2 confers substantial BLN resistance to the parasites by rapid drug efflux. The BLN-resistant promastigotes when transformed into amastigotes in macrophage cells cannot be cured by treatment of macrophages with BLN. Amastigote resistance is concomitant with the overexpression of macrophage MRP2 transporter. Reporter analysis and site-directed mutagenesis assays demonstrated that antioxidant response element 1 is activated upon infection. The expression of this phase II detoxifying gene is regulated by NFE2-related factor 2 (Nrf2)-mediated antioxidant response element activation. In view of the fact that the signaling pathway of phosphoinositol 3-kinase controls microfilament rearrangement and translocation of actin-associated proteins, the current study correlates with the intricate pathway of phosphoinositol 3-kinase-mediated nuclear translocation of Nrf2, which activates MRP2 expression in macrophages upon infection by the parasites. In contrast, phalloidin, an agent that prevents depolymerization of actin filaments, inhibits Nrf2 translocation and Mrp2 gene activation by pB25R infection. Taken together, these results provide insight into the mechanisms by which resistant clinical isolates of L. donovani induce intracellular events relevant to drug resistance. PMID:24706751

Beta-catenin phosphorylated at serine 45 is spatially uncoupled from beta-catenin phosphorylated in the GSK3 domain: implications for signaling.

PubMed

Maher, Meghan T; Mo, Rigen; Flozak, Annette S; Peled, Ofra N; Gottardi, Cara J

2010-04-16

C. elegans and Drosophila generate distinct signaling and adhesive forms of beta-catenin at the level of gene expression. Whether vertebrates, which rely on a single beta-catenin gene, generate unique adhesive and signaling forms at the level of protein modification remains unresolved. We show that beta-catenin unphosphorylated at serine 37 (S37) and threonine 41 (T41), commonly referred to as transcriptionally Active beta-Catenin (ABC), is a minor nuclear-enriched monomeric form of beta-catenin in SW480 cells, which express low levels of E-cadherin. Despite earlier indications, the superior signaling activity of ABC is not due to reduced cadherin binding, as ABC is readily incorporated into cadherin contacts in E-cadherin-restored cells. Beta-catenin phosphorylated at serine 45 (S45) or threonine 41 (T41) (T41/S45) or along the GSK3 regulatory cassette S33, S37 or T41 (S33/37/T41), however, is largely unable to associate with cadherins. Beta-catenin phosphorylated at T41/S45 and unphosphorylated at S37 and T41 is predominantly nuclear, while beta-catenin phosphorylated at S33/37/T41 is mostly cytoplasmic, suggesting that beta-catenin hypophosphorylated at S37 and T41 may be more active in transcription due to its enhanced nuclear accumulation. Evidence that phosphorylation at T41/S45 can be spatially separated from phosphorylations at S33/37/T41 suggests that these phosphorylations may not always be coupled, raising the possibility that phosphorylation at S45 serves a distinct nuclear function.

Genetic and Genomic Insights into the Role of Benzoate-Catabolic Pathway Redundancy in Burkholderia xenovorans LB400†

PubMed Central

Denef, V. J.; Klappenbach, J. A.; Patrauchan, M. A.; Florizone, C.; Rodrigues, J. L. M.; Tsoi, T. V.; Verstraete, W.; Eltis, L. D.; Tiedje, J. M.

2006-01-01

Transcriptomic and proteomic analyses of Burkholderia xenovorans LB400, a potent polychlorinated biphenyl (PCB) degrader, have implicated growth substrate- and phase-dependent expression of three benzoate-catabolizing pathways: a catechol ortho cleavage (ben-cat) pathway and two benzoyl-coenzyme A pathways, encoded by gene clusters on the large chromosome (boxC) and the megaplasmid (boxM). To elucidate the significance of this apparent redundancy, we constructed mutants with deletions of the ben-cat pathway (the ΔbenABCD::kan mutant), the boxC pathway (the ΔboxABC::kan mutant), and both pathways (the ΔbenABCDΔ boxABC::kan mutant). All three mutants oxidized benzoate in resting-cell assays. However, the ΔbenABCD::kan and ΔbenABCD ΔboxABC::kan mutants grew at reduced rates on benzoate and displayed increased lag phases. By contrast, growth on succinate, on 4-hydroxybenzoate, and on biphenyl was unaffected. Microarray and proteomic analyses revealed that cells of the ΔbenABCD::kan mutant growing on benzoate expressed both box pathways. Overall, these results indicate that all three pathways catabolize benzoate. Deletion of benABCD abolished the ability of LB400 to grow using 3-chlorobenzoate. None of the benzoate pathways could degrade 2- or 4-chlorobenzoate, indicating that the pathway redundancy does not directly contribute to LB400's PCB-degrading capacities. Finally, an extensive sigmaE-regulated oxidative stress response not present in wild-type LB400 grown on benzoate was detected in these deletion mutants, supporting our earlier suggestion that the box pathways are preferentially active under reduced oxygen tension. Our data further substantiate the expansive network of tightly interconnected and complexly regulated aromatic degradation pathways in LB400. PMID:16391095

Evolutionary Trajectories of Entomopathogenic Fungi ABC Transporters.

PubMed

Baral, Bikash

2017-01-01

The ABC protein superfamily-also called traffic ATPases-are energy-dependent ubiquitous proteins, representing one of the crucial and the largest family in the fungal genomes. The ATP-binding cassette endows a characteristic 200-250 amino acids and is omnipresent in all organisms ranging from prokaryotes to eukaryotes. Unlike in bacteria with nutrient import functions, ABC transporters in fungal entomopathogens serve as effective efflux pumps that are largely involved in the shuttle of metabolites across the biological membranes. Thus, the search for ABC proteins may prove of immense importance in elucidating the functional and molecular mechanism at the host-pathogen (insect-fungus) interface. Their sequence homology, domain topology, and functional traits led to the actual identification of nine different families in fungal entomopathogens. Evolutionary relationships within the ABC superfamily are discussed, concentrating on computational approaches for comparative identification of ABC transporters in insect-pathogenic fungi (entomopathogens) with those of animals, plants, and their bacterial orthologs. Ancestors of some fungal candidates have duplicated extensively in some phyla, while others were lost in one lineage or the other, and predictions for the cause of their duplications and/or loss in some phyla are made. ABC transporters of fungal insect-pathogens serve both defensive and offensive functions effective against land-dwelling and ground foraging voracious insects. This study may help to unravel the molecular cascades of ABC proteins to illuminate the means through which insects cope with fungal infection and fungal-related diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

Implication of RuvABC and RecG in homologous recombination in Streptomyces ambofaciens.

PubMed

Hoff, Grégory; Bertrand, Claire; Piotrowski, Emilie; Thibessard, Annabelle; Leblond, Pierre

2017-01-01

Most bacterial organisms rely on homologous recombination to repair DNA double-strand breaks and for the post-replicative repair of DNA single-strand gaps. Homologous recombination can be divided into three steps: (i) a pre-synaptic step in which the DNA 3'-OH ends are processed, (ii) a recA-dependent synaptic step allowing the invasion of an intact copy and the formation of Holliday junctions, and (iii) a post-synaptic step consisting of migration and resolution of these junctions. Currently, little is known about factors involved in homologous recombination, especially for the post-synaptic step. In Escherichia coli, branch migration and resolution are performed by the RuvABC complex, but could also rely on the RecG helicase in a redundant manner. In this study, we show that recG and ruvABC are well-conserved among Streptomyces. ΔruvABC, ΔrecG and ΔruvABC ΔrecG mutant strains were constructed. ΔruvABC ΔrecG is only slightly affected by exposure to DNA damage (UV). We also show that conjugational recombination decreases in the absence of RuvABC and RecG, but that intra-chromosomal recombination is not affected. These data suggest that RuvABC and RecG are indeed involved in homologous recombination in Streptomyces ambofaciens and that alternative factors are able to take over Holliday junction in Streptomyces. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Is there continued evidence for an association between abacavir usage and myocardial infarction risk in individuals with HIV? A cohort collaboration.

PubMed

Sabin, Caroline A; Reiss, Peter; Ryom, Lene; Phillips, Andrew N; Weber, Rainer; Law, Matthew; Fontas, Eric; Mocroft, Amanda; de Wit, Stephane; Smith, Colette; Dabis, Francois; d'Arminio Monforte, Antonella; El-Sadr, Wafaa; Lundgren, Jens D

2016-03-31

In March 2008, the D:A:D study published results demonstrating an increased risk of myocardial infarction (MI) for patients on abacavir (ABC). We describe changes to the use of ABC since this date, and investigate changes to the association between ABC and MI with subsequent follow-up. A total of 49,717 D:A:D participants were followed from study entry until the first of an MI, death, 1 February 2013 or 6 months after last visit. Associations between a person's 10-year cardiovascular disease (CVD) risk and the likelihood of initiating or discontinuing ABC were assessed using multivariable logistic/Poisson regression. Poisson regression was used to assess the association between current ABC use and MI risk, adjusting for potential confounders, and a test of interaction was performed to assess whether the association had changed in the post-March 2008 period. Use of ABC increased from 10 % of the cohort in 2000 to 20 % in 2008, before stabilising at 18-19 %. Increases in use pre-March 2008, and subsequent decreases, were greatest in those at moderate and high CVD risk. Post-March 2008, those on ABC at moderate/high CVD risk were more likely to discontinue ABC than those at low/unknown CVD risk, regardless of viral load (≤1,000 copies/ml: relative rate 1.49 [95 % confidence interval 1.34-1.65]; >1,000 copies/ml: 1.23 [1.02-1.48]); no such associations were seen pre-March 2008. There was some evidence that antiretroviral therapy (ART)-naïve persons at moderate/high CVD risk post-March 2008 were less likely to initiate ABC than those at low/unknown CVD risk (odds ratio 0.74 [0.48-1.13]). By 1 February 2013, 941 MI events had occurred in 367,559 person-years. Current ABC use was associated with a 98 % increase in MI rate (RR 1.98 [1.72-2.29]) with no difference in the pre- (1.97 [1.68-2.33]) or post- (1.97 [1.43-2.72]) March 2008 periods (interaction P = 0.74). Despite a reduction in the channelling of ABC for patients at higher CVD risk since 2008, we continue to observe an association between ABC use and MI risk. Whilst confounding cannot be fully ruled out, this further diminishes channelling bias as an explanation for our findings.

A novel chalcone derivative which acts as a microtubule depolymerising agent and an inhibitor of P-gp and BCRP in in-vitro and in-vivo glioblastoma models

PubMed Central

2009-01-01

Background Over the past decades, in spite of intensive search, no significant increase in the survival of patients with glioblastoma has been obtained. The role of the blood-brain barrier (BBB) and especially the activity of efflux pumps belonging to the ATP Binding Cassette (ABC) family may, in part, explain this defect. Methods The in-vitro activities of JAI-51 on cell proliferation were assessed by various experimental approaches in four human and a murine glioblastoma cell lines. Using drug exclusion assays and flow-cytometry, potential inhibitory effects of JAI-51 on P-gp and BCRP were evaluated in sensitive or resistant cell lines. JAI-51 activity on in-vitro microtubule polymerization was assessed by tubulin polymerization assay and direct binding measurements by analytical ultracentrifugation. Finally, a model of C57BL/6 mice bearing subcutaneous GL26 glioblastoma xenografts was used to assess the activity of the title compound in vivo. An HPLC method was designed to detect JAI-51 in the brain and other target organs of the treated animals, as well as in the tumours. Results In the four human and the murine glioblastoma cell lines tested, 10 μM JAI-51 inhibited proliferation and blocked cells in the M phase of the cell cycle, via its activity as a microtubule depolymerising agent. This ligand binds to tubulin with an association constant of 2 × 105 M-1, overlapping the colchicine binding site. JAI-51 also inhibited the activity of P-gp and BCRP, without being a substrate of these efflux pumps. These in vitro studies were reinforced by our in vivo investigations of C57BL/6 mice bearing GL26 glioblastoma xenografts, in which JAI-51 induced a delay in tumour onset and a tumour growth inhibition, following intraperitoneal administration of 96 mg/kg once a week. In accordance with these results, JAI-51 was detected by HPLC in the tumours of the treated animals. Moreover, JAI-51 was detected in the brain, showing that the molecule is also able to cross the BBB. Conclusion These in vitro and in vivo data suggest that JAI-51 could be a good candidate for a new treatment of tumours of the CNS. Further investigations are in progress to associate the title compound chemotherapy to radiotherapy in a rat model. PMID:19619277

Interaction studies reveal specific recognition of an anti-inflammatory polyphosphorhydrazone dendrimer by human monocytes

NASA Astrophysics Data System (ADS)

Ledall, Jérémy; Fruchon, Séverine; Garzoni, Matteo; Pavan, Giovanni M.; Caminade, Anne-Marie; Turrin, Cédric-Olivier; Blanzat, Muriel; Poupot, Rémy

2015-10-01

Dendrimers are nano-materials with perfectly defined structure and size, and multivalency properties that confer substantial advantages for biomedical applications. Previous work has shown that phosphorus-based polyphosphorhydrazone (PPH) dendrimers capped with azabisphosphonate (ABP) end groups have immuno-modulatory and anti-inflammatory properties leading to efficient therapeutic control of inflammatory diseases in animal models. These properties are mainly prompted through activation of monocytes. Here, we disclose new insights into the molecular mechanisms underlying the anti-inflammatory activation of human monocytes by ABP-capped PPH dendrimers. Following an interdisciplinary approach, we have characterized the physicochemical and biological behavior of the lead ABP dendrimer with model and cell membranes, and compared this experimental set of data to predictive computational modelling studies. The behavior of the ABP dendrimer was compared to the one of an isosteric analog dendrimer capped with twelve azabiscarboxylate (ABC) end groups instead of twelve ABP end groups. The ABC dendrimer displayed no biological activity on human monocytes, therefore it was considered as a negative control. In detail, we show that the ABP dendrimer can bind both non-specifically and specifically to the membrane of human monocytes. The specific binding leads to the internalization of the ABP dendrimer by human monocytes. On the contrary, the ABC dendrimer only interacts non-specifically with human monocytes and is not internalized. These data indicate that the bioactive ABP dendrimer is recognized by specific receptor(s) at the surface of human monocytes.Dendrimers are nano-materials with perfectly defined structure and size, and multivalency properties that confer substantial advantages for biomedical applications. Previous work has shown that phosphorus-based polyphosphorhydrazone (PPH) dendrimers capped with azabisphosphonate (ABP) end groups have immuno-modulatory and anti-inflammatory properties leading to efficient therapeutic control of inflammatory diseases in animal models. These properties are mainly prompted through activation of monocytes. Here, we disclose new insights into the molecular mechanisms underlying the anti-inflammatory activation of human monocytes by ABP-capped PPH dendrimers. Following an interdisciplinary approach, we have characterized the physicochemical and biological behavior of the lead ABP dendrimer with model and cell membranes, and compared this experimental set of data to predictive computational modelling studies. The behavior of the ABP dendrimer was compared to the one of an isosteric analog dendrimer capped with twelve azabiscarboxylate (ABC) end groups instead of twelve ABP end groups. The ABC dendrimer displayed no biological activity on human monocytes, therefore it was considered as a negative control. In detail, we show that the ABP dendrimer can bind both non-specifically and specifically to the membrane of human monocytes. The specific binding leads to the internalization of the ABP dendrimer by human monocytes. On the contrary, the ABC dendrimer only interacts non-specifically with human monocytes and is not internalized. These data indicate that the bioactive ABP dendrimer is recognized by specific receptor(s) at the surface of human monocytes. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03884g

76 FR 42710 - Statement of Organization, Functions, and Delegations of Authority

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-19

..., Functions, and Delegations of Authority Part A, Office of the Secretary, Statement of Organization, Functions, and Delegations of Authority for the Department of Health and Human Services is being amended at... (ABC1). V. Under Chapter ABC, Section ABC.20 Functions, 2nd paragraph, replace ``State, tribal, and...

ABCs of Being Smart: S Is for Supporting

ERIC Educational Resources Information Center

Foster, Joanne

2014-01-01

Joanne Foster's article "R We There Yet?" was first published in "Parenting for High Potential" ("PHP") in 2006, which became the springboard for the "ABCs of Being Smart" series of columns. At that time, Foster invited "PHP" readers to think about their own versions of the "ABCs of Being…

75 FR 6706 - In the Matter of Certain Foldable Stools; Notice of Commission Decision Not To Review an Initial...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-10

... Distributing and Crate & Barrel with ``LTD Commodities, LLC, d/b/a abc Distributing'' and ``Euromarket Designs... of investigation named several respondents including the following: abc Distributing Inc. (``abc Distributing'') of Bannockburn, Illinois; Crate & Barrel, Inc. (``Crate & Barrel'') of Northbrook, Illinois...

ABC's of Construction. Final Report.

ERIC Educational Resources Information Center

Greater Baton Rouge Chamber of Commerce, LA.

The ABC's of Construction project was a demonstration project designed to integrate basic skills training with an industry-developed vocational-craft training program. The program was located at the central training facility of the Pelican Chapter of Associated Builders and Contractors (ABC), an organization made up of nearly 300 member companies…

The ABCs of Activity-Based Costing: A Cost Containment and Reallocation Tool.

ERIC Educational Resources Information Center

Turk, Frederick J.

1992-01-01

This article describes activity-based costing (ABC) and how this tool may help management understand the costs of major activities and identify possible alternatives. Also discussed are the traditional costing systems used by higher education and ways of applying ABC to higher education. (GLR)

Do You Know Your ABC?

ERIC Educational Resources Information Center

Neale, Claire

2013-01-01

Within primary schools, the core subjects of literacy and numeracy are highly regarded, and rightly so, as children need to learn to read, write and be numerically literate. This means that all children learn their ABCs at an early age, But, what about the "other ABC"--"Airway, Breathing and Circulation?" Accidents and medical…

Meta-Analysis of the Validation Studies of the Kaufman Assessment Battery for Children.

ERIC Educational Resources Information Center

Ochieng, Charles O.

2003-01-01

Conducted a meta-analysis of the Kaufman Assessment Battery for Children (K-ABC) to ascertain the numbers of factors in the mental processing subtest of the K-ABC. Analyses yielded sequential and simultaneous processing factors, suggesting that the original K-ABC theory was not supported. (SLD)

GPS-ABC radiated chamber testing overview and results : GPS-ABC Workshop VI : RTCA Washington, DC, March 30, 2017.

DOT National Transportation Integrated Search

2017-03-30

This presentation, which was given during the GPS-ABC Workshop VI in Washington, DC on March 30, 2017 details the authors' radiated testing protocols and results. GPS receiver testing was carried out April 25-29, 2016 at the Army : Research Laborator...

fbpABC gene cluster in Neisseria meningitidis is transcribed as an operon.

PubMed

Khun, H H; Deved, V; Wong, H; Lee, B C

2000-12-01

The neisserial fbpABC locus has been proposed to constitute a single transcriptional unit. To confirm this operonic arrangement, transcription assays using reverse transcriptase PCR amplification were conducted with Neisseria meningitidis. The presence of fbpAB and fbpBC transcripts obtained by priming cDNA synthesis with an fbpC-sequence-specific oligonucleotide indicates that fbpABC is organized as a single expression unit. The ratio of fbpA to fbpABC mRNA was approximately between 10- to 20-fold, as determined by real-time quantitative PCR.

fbpABC Gene Cluster in Neisseria meningitidis Is Transcribed as an Operon

PubMed Central

Khun, Heng H.; Deved, Vinay; Wong, Howard; Lee, B. Craig

2000-01-01

The neisserial fbpABC locus has been proposed to constitute a single transcriptional unit. To confirm this operonic arrangement, transcription assays using reverse transcriptase PCR amplification were conducted with Neisseria meningitidis. The presence of fbpAB and fbpBC transcripts obtained by priming cDNA synthesis with an fbpC-sequence-specific oligonucleotide indicates that fbpABC is organized as a single expression unit. The ratio of fbpA to fbpABC mRNA was approximately between 10- to 20-fold, as determined by real-time quantitative PCR. PMID:11083849

Placental ABC Transporters: Biological Impact and Pharmaceutical Significance.

PubMed

Joshi, Anand A; Vaidya, Soniya S; St-Pierre, Marie V; Mikheev, Andrei M; Desino, Kelly E; Nyandege, Abner N; Audus, Kenneth L; Unadkat, Jashvant D; Gerk, Phillip M

2016-12-01

The human placenta fulfills a variety of essential functions during prenatal life. Several ABC transporters are expressed in the human placenta, where they play a role in the transport of endogenous compounds and may protect the fetus from exogenous compounds such as therapeutic agents, drugs of abuse, and other xenobiotics. To date, considerable progress has been made toward understanding ABC transporters in the placenta. Recent studies on the expression and functional activities are discussed. This review discusses the placental expression and functional roles of several members of ABC transporter subfamilies B, C, and G including MDR1/P-glycoprotein, the MRPs, and BCRP, respectively. Since placental ABC transporters modulate fetal exposure to various compounds, an understanding of their functional and regulatory mechanisms will lead to more optimal medication use when necessary in pregnancy.

Placental ABC Transporters: Biological Impact and Pharmaceutical Significance

PubMed Central

Joshi, Anand A.; Vaidya, Soniya S.; St-Pierre, Marie V.; Mikheev, Andrei M.; Desino, Kelly E.; Nyandege, Abner N.; Audus, Kenneth L.; Unadkat, Jashvant D.; Gerk, Phillip M.

2017-01-01

The human placenta fulfills a variety of essential functions during prenatal life. Several ABC transporters are expressed in the human placenta, where they play a role in the transport of endogenous compounds and may protect the fetus from exogenous compounds such as therapeutic agents, drugs of abuse, and other xenobiotics. To date, considerable progress has been made toward understanding ABC transporters in the placenta. Recent studies on the expression and functional activities are discussed. This review discusses the placental expression and functional roles of several members of ABC transporter subfamilies B, C, and G including MDR1/P-glycoprotein, the MRPs, and BCRP, respectively. Since placental ABC transporters modulate fetal exposure to various compounds, an understanding of their functional and regulatory mechanisms will lead to more optimal medication use when necessary in pregnancy. PMID:27644937

Purification and characterization of chondroitinase ABC from Acinetobacter sp. C26.

PubMed

Zhu, Changliang; Zhang, Jingliang; Zhang, Jing; Jiang, Yanhui; Shen, Zhaopeng; Guan, Huashi; Jiang, Xiaolu

2017-02-01

An extracellular chondroitinase ABC (ChSase ABC, EC 4.2.2.4) produced by cultivating Acinetobacter sp. C26, was purified to homogeneity from the supernatant by ammonium sulfate fractionation, Q-Sepharose Fast Flow and Sephadex G-100 chromatography. The 76kDa enzyme was purified 48.09-fold to homogeneity with specific activity of 348.64U/mg, Using the chondroitin sulfate A (CS-A) as substrate, the maximal reaction rate (Vmax) and Michaelis-Menten constant (Km) of ChSase ABC were found to be 10.471μmol/min/ml and 0.105mg/ml, respectively. The enzyme showed the highest activity at the optimal conditions of pH 6.0 and 42 ∘C, respectively. This enzyme was stable at pH 5-10, 5-9 and 5-7 at 4°C, 37°C and 42°C, respectively. Investigation about thermal stability of ChSase ABC displayed that it was stable at 37°C. ChSase ABC activity was increased in presence of Na + , K + , Mn 2+ , 1,10-phenanthrolin and strongly inhibited by Cu 2+ , Hg 2+ , Al 3+ and SDS. These properties suggested that ChSase ABC from Acinetobacter sp. C26 bring promising prospects in medical and industry applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Abc Amino Acids: Design, Synthesis, and Properties of New Photoelastic Amino Acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Standaert, Robert F; Park, Dr Seung Bum

2006-01-01

Photoisomerizable amino acids provide a direct avenue to the experimental manipulation of bioactive polypeptides, potentially allowing real-time, remote control of biological systems and enabling useful applications in nanobiotechnology. Herein, we report a new class of photoisomerizable amino acids intended to cause pronounced expansion and contraction in the polypeptide backbone, i.e., to be photoelastic. These compounds, termed Abc amino acids, employ a photoisomerizable azobiphenyl chromophore to control the relative disposition of aminomethyl and carboxyl substituents. Molecular modeling of nine Abc isomers led to the identification of one with particularly attractive properties, including the ability to induce contractions up to 13A inmore » the backbone upon transa?cis photoisomerization. This isomer, designated mpAbc, has substituents at meta and para positions on the inner (azo-linked) and outer rings, respectively. An efficient synthesis of Fmoc-protected mpAbc was executed in which the biaryl components were formed via Suzuki couplings and the azo linkage was formed via amine/nitroso condensation; protected forms of three other Abc isomers were prepared similarly. A decapeptide incorporating mpAbc was synthesized by conventional solid-phase methods and displayed characteristic azobenzene photochemical behavior with optimal conversion to the cis isomer at 360 nm and a thermal cisa?trans half life of 100 min. at 80 AoC.« less

Interaction of Oligomeric Breast Cancer Resistant Protein (BCRP) with Adjudin: A Male Contraceptive with Anti-Cancer Activity

PubMed Central

Cheng, Yan Ho; Jenardhanan, Pranitha; Mathur, Premendu P.; Qian, Xiaojing; Xia, Weiliang; Silvestrini, Bruno; Cheng, Chuen Yan

2016-01-01

Breast cancer resistant protein (BCRP, ABCG2) is an ATP-binding cassette (ABC) transporter, which together with two other ABC efflux drug pumps, namely P-glycoprotein (P-gp, ABCB1) and multidrug resistance-related protein 1 (MRP1, ABCC1) is the most important multidrug resistance protein found in eukaryotic cells including cells in the testis. However, unlike P-gp and MRP1, which are components of the Sertoli cell blood-testis barrier (BTB), BCRP is not expressed at the BTB in rodents and human testes. Instead, BCRP is expressed by peritubular myoid cells and endothelial cells of the lymphatic vessel in the tunica propria, residing outside the BTB. As such, the testis is equipped with two levels of defense against xenobiotics or drugs, preventing these harmful substances from entering the adluminal compartment to perturb meiosis and post-meiotic spermatid development: one at the level of the BTB conferred by P-gp and MRP1 and one at the tunica propria conferred by BCRP. The presence of drug transporters at the tunica propria as well as at the Sertoli cell BTB thus poses significant obstacles in developing non-hormonal contraceptives if these drugs (e.g., adjudin) exert their effects in germ cells behind the BTB, such as in the adluminal (apical) compartment of the seminiferous epithelium. Herein, we summarize recent findings pertinent to adjudin, a non-hormonal male contraceptive, and molecular interactions of adjudin with BCRP so that this information can be helpful to devise delivery strategies to evade BCRP in the tunica propria to improve its bioavailability in the testis. PMID:25620224

Diffuse large B-cell lymphoma patient-derived xenograft models capture the molecular and biological heterogeneity of the disease.

PubMed

Chapuy, Bjoern; Cheng, Hongwei; Watahiki, Akira; Ducar, Matthew D; Tan, Yuxiang; Chen, Linfeng; Roemer, Margaretha G M; Ouyang, Jing; Christie, Amanda L; Zhang, Liye; Gusenleitner, Daniel; Abo, Ryan P; Farinha, Pedro; von Bonin, Frederike; Thorner, Aaron R; Sun, Heather H; Gascoyne, Randy D; Pinkus, Geraldine S; van Hummelen, Paul; Wulf, Gerald G; Aster, Jon C; Weinstock, David M; Monti, Stefano; Rodig, Scott J; Wang, Yuzhuo; Shipp, Margaret A

2016-05-05

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease defined by transcriptional classifications, specific signaling and survival pathways, and multiple low-frequency genetic alterations. Preclinical model systems that capture the genetic and functional heterogeneity of DLBCL are urgently needed. Here, we generated and characterized a panel of large B-cell lymphoma (LBCL) patient-derived xenograft (PDX) models, including 8 that reflect the immunophenotypic, transcriptional, genetic, and functional heterogeneity of primary DLBCL and 1 that is a plasmablastic lymphoma. All LBCL PDX models were subjected to whole-transcriptome sequencing to classify cell of origin and consensus clustering classification (CCC) subtypes. Mutations and chromosomal rearrangements were evaluated by whole-exome sequencing with an extended bait set. Six of the 8 DLBCL models were activated B-cell (ABC)-type tumors that exhibited ABC-associated mutations such as MYD88, CD79B, CARD11, and PIM1. The remaining 2 DLBCL models were germinal B-cell type, with characteristic alterations of GNA13, CREBBP, and EZH2, and chromosomal translocations involving IgH and either BCL2 or MYC Only 25% of the DLBCL PDX models harbored inactivating TP53 mutations, whereas 75% exhibited copy number alterations of TP53 or its upstream modifier, CDKN2A, consistent with the reported incidence and type of p53 pathway alterations in primary DLBCL. By CCC criteria, 6 of 8 DLBCL PDX models were B-cell receptor (BCR)-type tumors that exhibited selective surface immunoglobulin expression and sensitivity to entospletinib, a recently developed spleen tyrosine kinase inhibitor. In summary, we have established and characterized faithful PDX models of DLBCL and demonstrated their usefulness in functional analyses of proximal BCR pathway inhibition. © 2016 by The American Society of Hematology.

Kinematics and force analysis of a robot hand based on an artificial biological control scheme

NASA Astrophysics Data System (ADS)

Kim, Man Guen

An artificial biological control scheme (ABCS) is used to study the kinematics and statics of a multifingered hand with a view to developing an efficient control scheme for grasping. The ABCS is based on observation of human grasping, intuitively taking it as the optimum model for robotic grasping. A final chapter proposes several grasping measures to be applied to the design and control of a robot hand. The ABCS leads to the definition of two modes of the grasping action: natural grasping (NG), which is the human motion to grasp the object without any special task command, and forced grasping (FG), which is the motion with a specific task. The grasping direction line (GDL) is defined to determine the position and orientation of the object in the hand. The kinematic model of a redundant robot arm and hand is developed by reconstructing the human upper extremity and using anthropometric measurement data. The inverse kinematic analyses of various types of precision and power grasping are studied by replacing the three-link with one virtual link and using the GDL. The static force analysis for grasping with fingertips is studied by applying the ABCS. A measure of grasping stability, that maintains the positions of contacts as well as the configurations of the redundant fingers, is derived. The grasping stability measure (GSM), a measure of how well the hand maintains grasping under the existence of external disturbance, is derived by the torque vector of the hand calculated from the external force applied to the object. The grasping manipulability measure (GMM), a measure of how well the hand manipulates the object for the task, is derived by the joint velocity vector of the hand calculated from the object velocity. The grasping performance measure (GPM) is defined by the sum of the directional components of the GSM and the GMM. Finally, a planar redundant hand with two fingers is examined in order to study the various postures of the hand performing pinch grasping by applying the GSM and the GMM.

The Role of RaxST, a Prokaryotic Sulfotransferase, and RaxABC, a Putative Type I Secretion System, in Activation of the Rice XA21-Mediated Immune Response

PubMed Central

Ronald, Pamela C.

2014-01-01

Tyrosine sulfation is an important posttranslational modification that determines the outcome of serious diseases in plants and animals. We have recently demonstrated that the plant pathogen Xanthomonas oryzae pv. oryzae (Xoo) carries a functional sulfotransferase (RaxST). raxST is required for activation of rice Xa21-mediated immunity indicating the critical, but unknown, function of raxST in mediating the Xoo/rice interaction. The raxST gene resides in the same operon (raxSTAB) as components of a predicted type I secretion and processing system (RaxA and RaxB). These observations suggest a model where RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS. PMID:25386383

The Role of RaxST, a Prokaryotic Sulfotransferase, and RaxABC, a Putative Type I Secretion System, in Activation of the Rice XA21-Mediated Immune Response.

PubMed

Ronald, Pamela C

2014-01-01

Tyrosine sulfation is an important posttranslational modification that determines the outcome of serious diseases in plants and animals. We have recently demonstrated that the plant pathogen Xanthomonas oryzae pv. oryzae (Xoo) carries a functional sulfotransferase (RaxST). raxST is required for activation of rice Xa21-mediated immunity indicating the critical, but unknown, function of raxST in mediating the Xoo/rice interaction. The raxST gene resides in the same operon (raxSTAB) as components of a predicted type I secretion and processing system (RaxA and RaxB). These observations suggest a model where RaxST sulfates a molecule that contains a leader peptide, which is cleaved by the peptidase domain of the RaxB protein and secreted outside the bacterial cell by the RaxABC T1SS.

Discovery of novel, high potent, ABC type PTP1B inhibitors with TCPTP selectivity and cellular activity.

PubMed

Liu, Peihong; Du, Yongli; Song, Lianhua; Shen, Jingkang; Li, Qunyi

2016-08-08

Protein tyrosine phosphatase 1B (PTP1B) as a key negative regulator of both insulin and leptin receptor pathways has been an attractive therapeutic target for the treatment of type 2 diabetes mellitus (T2DM) and obesity. With the goal of enhancing potency and selectivity of the PTP1B inhibitors, a series of methyl salicylate derivatives as ABC type PTP1B inhibitors (P1-P7) were discovered. More importantly, compound P6 exhibited high potent inhibitory activity (IC50 = 50 nM) for PTP1B with 15-fold selectivity over T-cell PTPase (TCPTP). Further studies on cellular activities revealed that compound P6 could enhance insulin-mediated insulin receptor β (IRβ) phosphorylation and insulin-stimulated glucose uptake. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

A giant cranial aneurysmal bone cyst associated with fibrous dysplasia.

PubMed

Składzieriń, J; Olés, K; Zagólski, O; Moskała, M; Sztuka, M; Strek, P; Wierzchowski, W; Tomik, J

2008-01-01

An aneurysmal bone cyst (ABC) is a rare, benign fibro-osseous lesion, considered a vascular phenomenon secondary to fibrous dysplasia or a giant-cell tumour, and occurs mainly in long bones and vertebrae. In this case report a 16-year-old male presented with massive epistaxis. He was admitted with a 3-year history of chronic rhinitis, headaches, right ocular pain and recurrent epistaxis. CT scans showed a predominantly cystic, expansive mass obstructing both nasal cavities, extending to all paranasal sinuses and both orbits, with evidence of anterior cranial fossa skull base destruction. The patient underwent a craniofacial resection of the tumour performed with an external approach and an immediate reconstruction of the dural defect. Histology confirmed the lesion was an ABC associated with fibrous dysplasia. The patient's recovery was complete. A large facial aneurysmal bone cyst can damage the facial skeleton and skull base, and requires excision by a combined external approach.

The impact of active breathing control on internal mammary lymph node coverage and normal tissue exposure in breast cancer patients planned for left-sided postmastectomy radiation therapy.

PubMed

Barry, Aisling; Rock, Kathy; Sole, Claudio; Rahman, Mohammad; Pintilie, Melania; Lee, Grace; Fyles, Anthony; Koch, C Anne

The purpose of this study was to evaluate the impact of the active breathing control (ABC) technique on IMN coverage and organs at risk in patients planned for postmastectomy radiation therapy (PMRT), with the inclusion of the internal mammary lymph nodes (IMNs). The effect of body mass index (BMI) on recorded dosimetric parameters was examined in the same patient cohort. Fifty left-sided postmastectomy patients with breast cancer who underwent free-breathing (FB) and ABC-Elekta CT simulation scans were selected at random from an institutional breast cancer database between 2008 and 2014. The ABC plans were directly compared with FB plans from the same patient. The IMN planning target volume coverage met dosimetric criteria for coverage of receiving more than 90% of the prescribed dose (V90) >90%, although it decreased with ABC compared with FB (94.5% vs 98%, P < .001). Overall, ABC significantly reduced doses to all measured heart and left anterior descending coronary artery parameters, ipsilateral lung V20, and mean lung dose compared with FB (P < .001). There was no difference seen between the ABC and FB plans with respect to the dose to contralateral lung or contralateral breast. There was no correlation identified between BMI and any of the dosimetric parameters recorded from the ABC and FB plans. Our results suggest that ABC reduces IMN coverage in left-sided breast cancer patients planned for PMRT; however, dosimetric criteria for IMN coverage were still met, suggesting that this is not likely to be clinically significant. ABC led to significant sparing of organs at risk compared with FB conditions and was not affected by BMI. Collectively, the results support the use of ABC for breast cancer patients undergoing left-sided PMRT requiring regional nodal irradiation that includes the IMNs. Further prospective clinical studies are required to determine the impact of these results on late normal tissue effects. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

ATP-binding cassette transporters in reproduction: a new frontier

PubMed Central

Bloise, E.; Ortiga-Carvalho, T.M.; Reis, F.M.; Lye, S.J.; Gibb, W.; Matthews, S.G.

2016-01-01

BACKGROUND The transmembrane ATP-binding cassette (ABC) transporters actively efflux an array of clinically relevant compounds across biological barriers, and modulate biodistribution of many physiological and pharmacological factors. To date, over 48 ABC transporters have been identified and shown to be directly and indirectly involved in peri-implantation events and fetal/placental development. They efflux cholesterol, steroid hormones, vitamins, cytokines, chemokines, prostaglandins, diverse xenobiotics and environmental toxins, playing a critical role in regulating drug disposition, immunological responses and lipid trafficking, as well as preventing fetal accumulation of drugs and environmental toxins. METHODS This review examines ABC transporters as important mediators of placental barrier functions and key reproductive processes. Expression, localization and function of all identified ABC transporters were systematically reviewed using PubMed and Google Scholar websites to identify relevant studies examining ABC transporters in reproductive tissues in physiological and pathophysiological states. Only reports written in English were incorporated with no restriction on year of publication. While a major focus has been placed on the human, extensive evidence from animal studies is utilized to describe current understanding of the regulation and function of ABC transporters relevant to human reproduction. RESULTS ABC transporters are modulators of steroidogenesis, fertilization, implantation, nutrient transport and immunological responses, and function as ‘gatekeepers’ at various barrier sites (i.e. blood-testes barrier and placenta) against potentially harmful xenobiotic factors, including drugs and environmental toxins. These roles appear to be species dependent and change as a function of gestation and development. The best-described ABC transporters in reproductive tissues (primarily in the placenta) are the multidrug transporters p-glycoprotein and breast cancer-related protein, the multidrug resistance proteins 1 through 5 and the cholesterol transporters ABCA1 and ABCG1. CONCLUSIONS The ABC transporters have various roles across multiple reproductive tissues. Knowledge of efflux direction, tissue distribution, substrate specificity and regulation of the ABC transporters in the placenta and other reproductive tissues is rapidly expanding. This will allow better understanding of the disposition of specific substrates within reproductive tissues, and facilitate development of novel treatments for reproductive disorders as well as improved approaches to protecting the developing fetus. PMID:26545808

Long-term bleeding risk prediction in 'real world' patients with atrial fibrillation: Comparison of the HAS-BLED and ABC-Bleeding risk scores. The Murcia Atrial Fibrillation Project.

PubMed

Esteve-Pastor, María Asunción; Rivera-Caravaca, José Miguel; Roldan, Vanessa; Vicente, Vicente; Valdés, Mariano; Marín, Francisco; Lip, Gregory Y H

2017-10-05

Risk scores in patients with atrial fibrillation (AF) based on clinical factors alone generally have only modest predictive value for predicting high risk patients that sustain events. Biomarkers might be an attractive prognostic tool to improve bleeding risk prediction. The new ABC-Bleeding score performed better than HAS-BLED score in a clinical trial cohort but has not been externally validated. The aim of this study was to analyze the predictive performance of the ABC-Bleeding score compared to HAS-BLED score in an independent "real-world" anticoagulated AF patients with long-term follow-up. We enrolled 1,120 patients stable on vitamin K antagonist treatment. The HAS-BLED and ABC-Bleeding scores were quantified. Predictive values were compared by c-indexes, IDI, NRI, as well as decision curve analysis (DCA). Median HAS-BLED score was 2 (IQR 2-3) and median ABC-Bleeding was 16.5 (IQR 14.3-18.6). After 6.5 years of follow-up, 207 (2.84 %/year) patients had major bleeding events, of which 65 (0.89 %/year) had intracranial haemorrhage (ICH) and 85 (1.17 %/year) had gastrointestinal bleeding events (GIB). The c-index of HAS-BLED was significantly higher than ABC-Bleeding for major bleeding (0.583 vs 0.518; p=0.025), GIB (0.596 vs 0.519; p=0.017) and for the composite of ICH-GIB (0.593 vs 0.527; p=0.030). NRI showed a significant negative reclassification for major bleeding and for the composite of ICH-GIB with the ABC-Bleeding score compared to HAS-BLED. Using DCAs, the use of HAS-BLED score gave an approximate net benefit of 4 % over the ABC-Bleeding score. In conclusion, in the first "real-world" validation of the ABC-Bleeding score, HAS-BLED performed significantly better than the ABC-Bleeding score in predicting major bleeding, GIB and the composite of GIB and ICH.

Simulation-based estimation of mean and standard deviation for meta-analysis via Approximate Bayesian Computation (ABC).

PubMed

Kwon, Deukwoo; Reis, Isildinha M

2015-08-12

When conducting a meta-analysis of a continuous outcome, estimated means and standard deviations from the selected studies are required in order to obtain an overall estimate of the mean effect and its confidence interval. If these quantities are not directly reported in the publications, they must be estimated from other reported summary statistics, such as the median, the minimum, the maximum, and quartiles. We propose a simulation-based estimation approach using the Approximate Bayesian Computation (ABC) technique for estimating mean and standard deviation based on various sets of summary statistics found in published studies. We conduct a simulation study to compare the proposed ABC method with the existing methods of Hozo et al. (2005), Bland (2015), and Wan et al. (2014). In the estimation of the standard deviation, our ABC method performs better than the other methods when data are generated from skewed or heavy-tailed distributions. The corresponding average relative error (ARE) approaches zero as sample size increases. In data generated from the normal distribution, our ABC performs well. However, the Wan et al. method is best for estimating standard deviation under normal distribution. In the estimation of the mean, our ABC method is best regardless of assumed distribution. ABC is a flexible method for estimating the study-specific mean and standard deviation for meta-analysis, especially with underlying skewed or heavy-tailed distributions. The ABC method can be applied using other reported summary statistics such as the posterior mean and 95 % credible interval when Bayesian analysis has been employed.

The feoABC Locus of Yersinia pestis Likely Has Two Promoters Causing Unique Iron Regulation

PubMed Central

O'Connor, Lauren; Fetherston, Jacqueline D.; Perry, Robert D.

2017-01-01

The FeoABC ferrous transporter is a wide-spread bacterial system. While the feoABC locus is regulated by a number of factors in the bacteria studied, we have previously found that regulation of feoABC in Yersinia pestis appears to be unique. None of the non-iron responsive transcriptional regulators that control expression of feoABC in other bacteria do so in Y. pestis. Another unique factor is the iron and Fur regulation of the Y. pestis feoABC locus occurs during microaerobic but not aerobic growth. Here we show that this unique iron-regulation is not due to a unique aspect of the Y. pestis Fur protein but to DNA sequences that regulate transcription. We have used truncations, alterations, and deletions of the feoA::lacZ reporter to assess the mechanism behind the failure of iron to repress transcription under aerobic conditions. These studies plus EMSAs and DNA sequence analysis have led to our proposal that the feoABC locus has two promoters: an upstream P1 promoter whose expression is relatively iron-independent but repressed under microaerobic conditions and the known downstream Fur-regulated P2 promoter. In addition, we have identified two regions that bind Y. pestis protein(s), although we have not identified these protein(s) or their function. Finally we used iron uptake assays to demonstrate that both FeoABC and YfeABCD transport ferrous iron in an energy-dependent manner and also use ferric iron as a substrate for uptake. PMID:28785546

A Manual for Implementation of ABC Video Duplication Projects.

ERIC Educational Resources Information Center

Hill, Joseph, Ed.

The ABC (Appalachian BOCES Consortium) consists of 10 BOCES (Boards of Cooperative Educational Services) which serve the 14 southern counties of New York State designated as Appalachia. Each year since 1974, the ABC has participated in regional video duplication projects, which have yielded a total of nearly 4,000 video titles. The complexity of…

Abrasive wear behavior of heat-treated ABC-silicon carbide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Xiao Feng; Lee, Gun Y.; Chen, Da

2002-06-17

Hot-pressed silicon carbide, containing aluminum, boron, and carbon additives (ABC-SiC), was subjected to three-body and two-body wear testing using diamond abrasives over a range of sizes. In general, the wear resistance of ABC-SiC, with suitable heat treatment, was superior to that of commercial SiC.

Creating an iPhone Application for Collecting Continuous ABC Data

ERIC Educational Resources Information Center

Whiting, Seth W.; Dixon, Mark R.

2012-01-01

This paper provides an overview and task analysis for creating a continuous ABC data- collection application using Xcode on a Mac computer. Behavior analysts can program an ABC data collection system, complete with a customized list of target clients, antecedents, behaviors, and consequences to be recorded, and have the data automatically sent to…

75 FR 42069 - Fisheries of the South Atlantic and Gulf of Mexico; South Atlantic Fishery Management Council...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-20

...) will hold a meeting of its Scientific and Statistical Committee (SSC) to discuss Acceptable Biological Catch (ABC) Control Rules, and recommend ABC values for South Atlantic managed species. See... discuss ABC control rules for stocks which do not have peer reviewed quantitative stock assessments and...

Parents' Perspectives on Braille Literacy: Results from the ABC Braille Study

ERIC Educational Resources Information Center

Kamei-Hannan, Cheryl; Sacks, Sharon Zell

2012-01-01

Introduction: Parents who were the primary caretakers of children in the Alphabetic and Contracted Braille Study (ABC Braille Study) revealed their perspectives about braille literacy. Methods: A 30-item questionnaire was constructed by the ABC Braille research team, and researchers conducted telephone interviews with 31 parents who were the…

Association of Serotonin Concentration to Behavior and IQ in Autistic Children.

ERIC Educational Resources Information Center

Kuperman, Samuel; And Others

1987-01-01

The IQ and behavior patterns on the Autism Behavior Checklist (ABC) of 25 boys were compared to blood concentrations of platelet rich plasma (PRP) serotonin. Although no correlations were found between serotonin levels and IQ or ABC scales, four individual ABC items did correlate with serotonin concentrations. (Author/DB)

Confirmatory Factor Analysis of the Kaufman Assessment Battery for Children: A Reevaluation.

ERIC Educational Resources Information Center

Strommen, Erik

1988-01-01

Performed confirmatory factor analyses of Kaufman Assessment Battery for Children (K-ABC) using subtest correlations for standardization samples provided in manuals to test hypothesis that factors underlying K-ABC are substantially intercorrelated at all age levels for two- and three-factor models. Findings suggest K-ABC cannot distinguish between…

78 FR 48860 - New England Fishery Management Council; Public Meetings

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-12

... ABC Control Rule Working Group (ABC WG) and Electronic Monitoring Working Group (EM WG). DATES: The first meeting of the ABC Control Rule Working Group will be on Tuesday, September 3, 2013. The meeting..., times and places for the meetings will be posted on the Council's Web site, http://nefmc.org/ . FOR...

School-Based Management and Accountability Procedures Manual

ERIC Educational Resources Information Center

North Carolina Department of Public Instruction, 2004

2004-01-01

From the mission, several principles were developed to guide the School-Based Management and Accountability Program (the ABCs). (1) The ABCs sets standards for student performance and growth in the basics that are the foundation for further learning and achievement; (2) The accountability system in the ABCs plan is designed to result in improved…

Molecular analysis of imipenem-resistant Acinetobacter baumannii isolated from US service members wounded in Iraq, 2003–2008

USDA-ARS?s Scientific Manuscript database

Clonal spread and global dissemination of imipenem resistant (IR) A. baumannii-A. calcoaceticus complex (ABC) have been reported in recent years. However, the epidemiological features of the IR-ABCs in military treatment facilities (MTFs) have not been systematically studied. In this study, 298 ABC...

Escalated convergent artificial bee colony

NASA Astrophysics Data System (ADS)

Jadon, Shimpi Singh; Bansal, Jagdish Chand; Tiwari, Ritu

2016-03-01

Artificial bee colony (ABC) optimisation algorithm is a recent, fast and easy-to-implement population-based meta heuristic for optimisation. ABC has been proved a rival algorithm with some popular swarm intelligence-based algorithms such as particle swarm optimisation, firefly algorithm and ant colony optimisation. The solution search equation of ABC is influenced by a random quantity which helps its search process in exploration at the cost of exploitation. In order to find a fast convergent behaviour of ABC while exploitation capability is maintained, in this paper basic ABC is modified in two ways. First, to improve exploitation capability, two local search strategies, namely classical unidimensional local search and levy flight random walk-based local search are incorporated with ABC. Furthermore, a new solution search strategy, namely stochastic diffusion scout search is proposed and incorporated into the scout bee phase to provide more chance to abandon solution to improve itself. Efficiency of the proposed algorithm is tested on 20 benchmark test functions of different complexities and characteristics. Results are very promising and they prove it to be a competitive algorithm in the field of swarm intelligence-based algorithms.

Enhanced High-Rate Shockwave Lithotripsy Stone Comminution in an In Vivo Porcine Model Using Acoustic Bubble Coalescence.

PubMed

Alavi Tamaddoni, Hedieh; Roberts, William W; Duryea, Alexander P; Cain, Charles A; Hall, Timothy L

2016-12-01

Cavitation plays a significant role in the efficacy of stone comminution during shockwave lithotripsy (SWL). Although cavitation on the surface of urinary stones helps to improve fragmentation, cavitation bubbles along the propagation path may shield or block subsequent shockwaves (SWs) and potentially induce collateral tissue damage. Previous in vitro work has shown that applying low-amplitude acoustic waves after each SW can force bubbles to consolidate and enhance SWL efficacy. In this study, the feasibility of applying acoustic bubble coalescence (ABC) in vivo was tested. Model stones were percutaneously implanted and treated with 2500 lithotripsy SWs at 120 SW/minute with or without ABC. Comparing the results of stone comminution, a significant improvement was observed in the stone fragmentation process when ABC was used. Without ABC, only 25% of the mass of the stone was fragmented to particles <2 mm in size. With ABC, 75% of the mass was fragmented to particles <2 mm in size. These results suggest that ABC can reduce the shielding effect of residual bubble nuclei, resulting in a more efficient SWL treatment.

ATP-binding cassette (ABC) proteins in aquatic invertebrates: Evolutionary significance and application in marine ecotoxicology.

PubMed

Jeong, Chang-Bum; Kim, Hui-Su; Kang, Hye-Min; Lee, Jae-Seong

2017-04-01

The ATP-binding cassette (ABC) protein superfamily is known to play a fundamental role in biological processes and is highly conserved across animal taxa. The ABC proteins function as active transporters for multiple substrates across the cellular membrane by ATP hydrolysis. As this superfamily is derived from a common ancestor, ABC genes have evolved via lineage-specific duplications through the process of adaptation. In this review, we summarized information about the ABC gene families in aquatic invertebrates, considering their evolution and putative functions in defense mechanisms. Phylogenetic analysis was conducted to examine the evolutionary significance of ABC gene families in aquatic invertebrates. Particularly, a massive expansion of multixenobiotic resistance (MXR)-mediated efflux transporters was identified in the absence of the ABCG2 (BCRP) gene in Ecdysozoa and Platyzoa, suggesting that a loss of Abcg2 gene occurred sporadically in these species during divergence of Protostome to Lophotrochozoa. Furthermore, in aquatic invertebrates, the ecotoxicological significance of MXR is discussed while considering the role of MXR-mediated efflux transporters in response to various environmental pollutants. Copyright © 2017 Elsevier B.V. All rights reserved.

Genome-wide identification of ATP-binding cassette (ABC) transporters and their roles in response to polycyclic aromatic hydrocarbons (PAHs) in the copepod Paracyclopina nana.

PubMed

Jeong, Chang-Bum; Kim, Duck-Hyun; Kang, Hye-Min; Lee, Young Hwan; Kim, Hui-Su; Kim, Il-Chan; Lee, Jae-Seong

2017-02-01

The ATP-binding cassette (ABC) protein superfamily is one of the largest gene families and is highly conserved in all domains. The ABC proteins play roles in several biological processes, including multi-xenobiotic resistance (MXR), by functioning as transporters in the cellular membrane. They also mediate the cellular efflux of a wide range of substrates against concentration gradients. In this study, 37 ABC genes belonging to eight distinct subfamilies were identified in the marine copepod Paracyclopina nana and annotated based on a phylogenetic analysis. Also, the functions of P-glycoproteins (P-gp) and multidrug resistance-associated proteins (MRPs), conferring MXR, were verified using fluorescent substrates and specific inhibitors. The activities of MXR-mediated ABC proteins and their transcriptional level were examined in response to polyaromatic hydrocarbons (PAHs), main components of the water-accommodated fraction. This study increases the understanding of the protective role of MXR in response to PAHs over the comparative evolution of ABC gene families. Copyright © 2016 Elsevier B.V. All rights reserved.

A hybrid artificial bee colony algorithm for numerical function optimization

NASA Astrophysics Data System (ADS)

Alqattan, Zakaria N.; Abdullah, Rosni

2015-02-01

Artificial Bee Colony (ABC) algorithm is one of the swarm intelligence algorithms; it has been introduced by Karaboga in 2005. It is a meta-heuristic optimization search algorithm inspired from the intelligent foraging behavior of the honey bees in nature. Its unique search process made it as one of the most competitive algorithm with some other search algorithms in the area of optimization, such as Genetic algorithm (GA) and Particle Swarm Optimization (PSO). However, the ABC performance of the local search process and the bee movement or the solution improvement equation still has some weaknesses. The ABC is good in avoiding trapping at the local optimum but it spends its time searching around unpromising random selected solutions. Inspired by the PSO, we propose a Hybrid Particle-movement ABC algorithm called HPABC, which adapts the particle movement process to improve the exploration of the original ABC algorithm. Numerical benchmark functions were used in order to experimentally test the HPABC algorithm. The results illustrate that the HPABC algorithm can outperform the ABC algorithm in most of the experiments (75% better in accuracy and over 3 times faster).

Factor validity and norms for the aberrant behavior checklist in a community sample of children with mental retardation.

PubMed

Marshburn, E C; Aman, M G

1992-09-01

The Aberrant Behavior Checklist (ABC) is a 58-item rating scale that was developed primarily to measure the effects of pharmacological intervention in individuals living in residential facilities. This study investigated the use of the ABC in a sample of community children with mental retardation. Teacher ratings on the ABC were collected on 666 students attending special classes. The data were factor analyzed and compared with other studies using the ABC. In addition, subscales were analyzed as a function of age, sex, and classroom placement, and preliminary norms were derived. A four-factor solution of the ABC was obtained. Congruence between the four derived factors and corresponding factors from the original ABC was high (congruence coefficients ranged between .87 and .96). Classroom placement and age had significant effects on subscale scores, whereas sex failed to affect ratings. The current results are sufficiently close to the original factor solution that the original scoring method can be used with community samples, although further studies are needed to look at this in more detail.

Withaferin A disrupts ubiquitin-based NEMO reorganization induced by canonical NF-κB signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Shawn S.; Medical Scientist Training Program, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705; Cellular and Molecular Biology Program, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53705

2015-02-01

The NF-κB family of transcription factors regulates numerous cellular processes, including cell proliferation and survival responses. The constitutive activation of NF-κB has also emerged as an important oncogenic driver in many malignancies, such as activated B-cell like diffuse large B cell lymphoma, among others. In this study, we investigated the impact and mechanisms of action of Withaferin A, a naturally produced steroidal lactone, against both signal-inducible as well as constitutive NF-κB activities. We found that Withaferin A is a robust inhibitor of canonical and constitutive NF-κB activities, leading to apoptosis of certain lymphoma lines. In the canonical pathway induced bymore » TNF, Withaferin A did not disrupt RIP1 polyubiquitination or NEMO–IKKβ interaction and was a poor direct IKKβ inhibitor, but prevented the formation of TNF-induced NEMO foci which colocalized with TNF ligand. While GFP-NEMO efficiently formed TNF-induced foci, a GFP-NEMO{sup Y308S} mutant that is defective in binding to polyubiquitin chains did not form foci. Our study reveals that Withaferin A is a novel type of IKK inhibitor which acts by disrupting NEMO reorganization into ubiquitin-based signaling structures in vivo. - Highlights: • Withaferin A, a NF-κB inhibitor, disrupts signaling induced NEMO localization, a novel point of inhibition. • NEMO can be localized to distinct signaling foci after treatment with TNF. • ABC-type DLCBL cells can be sensitized to apoptosis after treatment with Withaferin A.« less

Lenalidomide combined with R-GDP in a patient with refractory CD5-positive diffuse large B-cell lymphoma: A promising response and review.

PubMed

Zhang, Yaping; Wang, Xinfeng; Liu, Yifei; Sun, Chunfeng; Shi, Wenyu; Huang, Hongming

2018-07-03

CD5-positive (CD5+) diffuse large B-cell lymphoma (DLBCL) is associated with poor survival compared with CD5-negative DLBCL. The clinical characteristics of CD5+ DLBCL are different from both CD5-negative DLBCL and other CD5+ B cell lymphomas. There is currently no promising chemotherapy for CD5+ DLBCL. Herein, we report a 49-year-old Asian male with refractory CD5+ DLBCL. He complained of aggravated abdominal pain and weight loss. Computed tomography scan revealed abdominal masses, widespread lymphadenopathy, splenomegaly, and intussusception of the ileocecal junction with bowel wall thickening. Core needle aspiration biopsy of an abdominal mass was performed and immunohistochemistry revealed DLBCL of nongerminal center type. In this report, the dose-intensified R-Hyper CVAD (A) regimen as salvage therapy was introduced but failed to result in substantial improvement over the initially standard R-CHOP regimen. Next, the R-GDP regimen was administered as second-line treatment, but only resulted in a partial response. However, the addition of lenalidomide to R-GDP (R2-GDP) resulted in complete remission. The clinical features, pathogenesis, and possible mechanism of action of lenalidomide in CD5+ DLBCL have been described in the literature. The results of the present case report and literature searches indicate that CD5+ DLBCL may share a common pathway with activated B-cell like (ABC) DLBCL as determined by gene expression profiling. Lenalidomide is expected to induce favorable responses in patients with CD5+ DLBCL.

Brassboard Astrometric Beam Combiner (ABC) Development for the Space Interferometry Mission (SIM)

NASA Technical Reports Server (NTRS)

Jeganathan, Muthu; Kuan, Gary; Rud, Mike; Lin, Sean; Sutherland, Kristen; Moore, James; An, Xin

2008-01-01

The Astrometric Beam Combiner (ABC) is a critical element of the Space Interferometry Mission (SIM) that performs three key functions: coherently combine starlight from two siderostats; individually detect starlight for angle tracking; and disperse and detect the interferometric fringes. In addition, the ABC contains: a stimulus, cornercubes and shutters for in-orbit calibration; several tip/tilt mirror mechanisms for in-orbit alignment; and internal metrology beam launcher for pathlength monitoring. The detailed design of the brassboard ABC (which has the form, fit and function of the flight unit) is complete, procurement of long-lead items is underway, and assembly and testing is expected to be completed in Spring 2009. In this paper, we present the key requirements for the ABC, details of the completed optical and mechanical design as well as plans for assembly and alignment.

Immune complexes formed following the binding of anti-platelet factor 4 (CXCL4) antibodies to CXCL4 stimulate human neutrophil activation and cell adhesion.

PubMed

Xiao, Zhihua; Visentin, Gian P; Dayananda, Kannayakanahalli M; Neelamegham, Sriram

2008-08-15

We tested the possibility that immune complexes formed following platelet factor 4 (PF4/CXCL4) binding to anti-PF4 antibody can stimulate neutrophil activation, similar to previous reports with platelets. Monoclonal Abs against PF4 and IgG from a heparin-induced thrombocytopenia (HIT) patient were applied. We observed that although PF4 or anti-PF4 antibody alone did not alter neutrophil function, costimulation with both reagents resulted in approximately 3-fold increase in cell surface Mac-1 expression, enhanced cell adhesion via L-selectin and CD18 integrins, and degranulation of secondary and tertiary granules. The level of Mac-1 up-regulation peaked at an intermediate PF4 dose, suggesting that functional response varies with antigen-antibody stoichiometry. PF4 binding to neutrophils was blocked by chondroitinase ABC. Cell activation was inhibited by both chondroitinase ABC and anti-CD32/FcgammaRII blocking mAb, IV.3. Confocal microscopy demonstrated that immune complexes colocalize with CD32a. Studies with HIT IgG demonstrated that neutrophils could be activated in the absence of exogenous heparin. These data, together, show that leukocyte surface chondroitin sulfates promote neutrophil activation by enhancing immune-complex binding to CD32a. Studies with recombinant PF4 suggest a role for arginine 49 in stabilizing PF4-chondroitin binding. Neutrophils activated via this mechanism may contribute to thrombosis and inflammation in patients mounting an immune response to PF4-heparin.