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Sample records for multidrug-resistant tumor cells

  1. Cell biological mechanisms of multidrug resistance in tumors.

    PubMed Central

    Simon, S M; Schindler, M

    1994-01-01

    Multidrug resistance (MDR) is a generic term for the variety of strategies tumor cells use to evade the cytotoxic effects of anticancer drugs. MDR is characterized by a decreased sensitivity of tumor cells not only to the drug employed for chemotherapy but also to a broad spectrum of drugs with neither obvious structural homology nor common targets. This pleiotropic resistance is one of the major obstacles to the successful treatment of tumors. MDR may result from structural or functional changes at the plasma membrane or within the cytoplasm, cellular compartments, or nucleus. Molecular mechanisms of MDR are discussed in terms of modifications in detoxification and DNA repair pathways, changes in cellular sites of drug sequestration, decreases in drug-target affinity, synthesis of specific drug inhibitors within cells, altered or inappropriate targeting of proteins, and accelerated removal or secretion of drugs. PMID:7909602

  2. The Impact of Cell Density and Mutations in a Model of Multidrug Resistance in Solid Tumors

    PubMed Central

    Greene, James; Lavi, Orit; Gottesman, Michael M.; Levy, Doron

    2016-01-01

    In this paper we develop a mathematical framework for describing multidrug resistance in cancer. To reflect the complexity of the underlying interplay between cancer cells and the therapeutic agent, we assume that the resistance level is a continuous parameter. Our model is written as a system of integro-differential equations that are parametrized by the resistance level. This model incorporates the cell-density and mutation dependence. Analysis and simulations of the model demonstrate how the dynamics evolves to a selection of one or more traits corresponding to different levels of resistance. The emerging limit distribution with nonzero variance is the desirable modeling outcome as it represents tumor heterogeneity. PMID:24553772

  3. Reversal effect of Tween-20 on multidrug resistance in tumor cells in vitro.

    PubMed

    Yang, Shouhui; Liu, Jinjuan; Chen, Yongqiang; Jiang, Jihong

    2012-04-01

    Multidrug resistance (MDR) is a major barrier for chemotherapy of many cancers. Non-ionic surfactants have great potential to reverse the MDR by preventing onset or delay progression of the carcinogenic process. However, the role of Tween-20 in the development of MDR remains unknown. The aim of this study was to explore the reversal effect and potential mechanism of Tween-20 on tumor cells in vitro. Alamar Blue assay was used to examine the reversal index of Tween-20 to vincristine (VCR), doxorubicin (DOX) and 5-fluorouracil (5-FU) in KBv200, HepG2/R and Bel-7402/5-FU, respectively. Morphological change was determined by Gimsa and Hoechst 33258 staining. The acumulation of DOX was confirmed by spectrofluorimetric assay. Cell cycle analysis was performed using flow cytometry. The mRNA and protein expression levels of MDR were assessed by semiquantitative RT-PCR and dot blot, respectively. The results showed that Tween-20 at concentrations of 0.0025%, 0.005%, 0.01% had little cytotoxicity. When combined with the cancer drugs, it significantly promoted the sensitivity of MDR cells. Fluorescence staining confirmed that the percentage of apoptotic cell increased when combined with Tween-20. This notion was further supported by the observation that Tween-20 treatment potentiated VIN-induced G2/M arrest of the cell cycle. Furthermore, Tween-20 treatment increased significantly intracellular accumulation of DOX. RT-PCR and dot blot revealed that Tween-20 could downregulate the expression of MDR and P-glycoprotein. Low concentrations of Tween-20 can efficiently reverse the multidrug resistance phenotype by enhancing accumulation of the anticancer drugs. The potential mechanism may be via inhibiting the multidrug-resistant gene expression.

  4. Laurus nobilis L. Seed Extract Reveals Collateral Sensitivity in Multidrug-Resistant P-Glycoprotein-Expressing Tumor Cells.

    PubMed

    Saab, Antoine M; Guerrini, Alessandra; Zeino, Maen; Wiench, Benjamin; Rossi, Damiano; Gambari, Roberto; Sacchetti, Gianni; Greten, Henry Johannes; Efferth, Thomas

    2015-01-01

    The frequent failure of standard cancer chemotherapy requires the development of novel drugs capable of killing otherwise drug-resistant tumors. Here, we have investigated a chloroform extract of Laurus nobilis seeds. Fatty acids and 23 constituents of the volatile fraction were identified by gas chromotography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS), in good agreement with (1)H NMR (nuclear magnetic resonance) spectrum. Multidrug-resistant P-glycoprotein-expressing CEM/ADR5000 leukemia cells were hypersensitive (collaterally sensitive) toward this extract compared to drug-sensitive CCRF-CEM cells, whereas CEM/ADR5000 cells were 2586-fold resistant to doxorubicin as control drug. Collateral sensitivity was verified by measurement of apoptotic cells by flow cytometry. The log10IC50 values of 3 compounds in the extract (limonene, eucalyptol, oleic acid) did not correlate with mRNA expression of the P-glycoprotein-coding ABCB1/MDR1 gene and accumulation of the P-glycoprotein substrate rhodamine in the NCI panel of tumor cell lines. A microarray-based profile of 20 genes predicted resistance to doxorubicin and 7 other anticancer drugs involved in the multidrug resistance phenotype but not to limonene, eucalyptol and oleic acid. In conclusion, our results show that Laurus nobilis seed extract is suitable to kill multidrug-resistant P-glycoprotein expressing tumor cells.

  5. Activity of the dietary flavonoid, apigenin, against multidrug-resistant tumor cells as determined by pharmacogenomics and molecular docking.

    PubMed

    Saeed, Mohamed; Kadioglu, Onat; Khalid, Hassan; Sugimoto, Yoshikazu; Efferth, Thomas

    2015-01-01

    Apigenin is a common dietary flavonoid with considerable cytotoxic activity in vitro and in vivo. Despite many mechanistic studies, less is known about resistance factors hampering apigenin's activity. We investigated the ATP-binding cassette (ABC) transporters BCRP/ABCG2, P-glycoprotein/ABCB1 and its close relative ABCB5. Multidrug-resistant cells overexpressing these ABC transporters were not cross-resistant toward apigenin. Moreover, apigenin inhibited not only P-glycoprotein but also BCRP by increasing cellular uptake of doxorubicin and synergistic inhibition of cell viability in combination with doxorubicin or docetaxel in multidrug-resistant cells. To perform in silico molecular docking studies, we first generated homology models for human P-glycoprotein and ABCB5 based on the crystal structure of murine P-glycoprotein. Their nucleotide binding domains (NDBs) revealed the highest degrees of sequence homologies (89%-100%), indicating that ATP binding and cleavage is of crucial importance for ABC transporters. Molecular docking of apigenin bound to the NDBs of P-glycoprotein and ABCB5 in molecular docking studies. Hence, apigenin may compete with ATP for NDB-binding leading to energy depletion to fuel the transport of ABC transporter substrates. Furthermore, we performed COMPARE and hierarchical cluster analyses of transcriptome-wide mRNA expression profiles of the National Cancer Institute tumor cell line panel. Microarray-based mRNA expressions of genes of diverse biological functions (signal transduction, transcriptional regulation, ubiquitination, autophagy, metabolic activity, xenobiotic detoxification and microtubule formation) significantly predicted responsiveness of tumor cells to apigenin. In conclusion, apigenin's activity is not hampered by classical mechanisms of multidrug resistance and the inhibition of ABC transporters by apigenin indicates that apigenin may overcome multidrug resistance in otherwise refractory tumors.

  6. Reversal effect and mechanism of Ginkgo biloba exocarp extracts in multidrug resistance of mice S180 tumor cells.

    PubMed

    Hu, Bi-Yuan; Gu, Yun-Hao; Cao, Chen-Jie; Wang, Jun; Han, Dong-Dong; Tang, Ying-Chao; Chen, Hua-Sheng; Xu, Aihua

    2016-10-01

    The aim of the present study was to investigate the reversal effect and its related mechanism of Ginkgo biloba exocarp extracts (GBEEs) in obtained multidrug resistance (MDR) of mice S180 tumor cells in vitro and in vivo. In order to simulate the clinical PFC [cis-dichlorodiamineplatinum, cisplatin (DDP) + fluorouracil (FU), FU+cyclophosphamide and cyclophosphamide] scheme, a gradually increasing dose was administered in a phased induction in order to induce S180 cells in vivo and to make them obtain multidrug resistance. The results in vitro demonstrated that GBEE could significantly increase the IC50 of DDP on S180 MDR cells, increase the accumulation of Adriamycin (ADR) and rhodamine 123 (Rho 123), and reduce the efflux of Rho 123 of S180 MDR cells. The results from the in vivo treatment with a combination of GBEE and DDP to S180 MDR ascites tumor in mice demonstrated that each dose of GBEE could effectively reverse the drug-resistance of S180 MDR cells to DDP in order to extend the survival time of mice with ascite tumors and inhibit tumor growth in solid tumor mice. In addition, GBEE effectively inhibited the expression of MDR-1 mRNA and multidrug resistance-associated protein-1 mRNA in S180 MDR cells of ascites tumor in mice and improved the expression levels of cytokines, including interleukin (IL)-3, IL-18 and interferon-γ in the blood serum of S180 MDR tumor-bearing mice. The present study showed that the mechanism of GBEE reversal of MDR may be associated with the inhibition of the functional activity of P-glycoprotein, the downregulation of drug resistance related gene expression of S180 MDR cells and the improvement of the production of related serum cytokines of S180 MDR tumor mice.

  7. Reversal effect and mechanism of Ginkgo biloba exocarp extracts in multidrug resistance of mice S180 tumor cells

    PubMed Central

    Hu, Bi-Yuan; Gu, Yun-Hao; Cao, Chen-Jie; Wang, Jun; Han, Dong-Dong; Tang, Ying-Chao; Chen, Hua-Sheng; Xu, Aihua

    2016-01-01

    The aim of the present study was to investigate the reversal effect and its related mechanism of Ginkgo biloba exocarp extracts (GBEEs) in obtained multidrug resistance (MDR) of mice S180 tumor cells in vitro and in vivo. In order to simulate the clinical PFC [cis-dichlorodiamineplatinum, cisplatin (DDP) + fluorouracil (FU), FU+cyclophosphamide and cyclophosphamide] scheme, a gradually increasing dose was administered in a phased induction in order to induce S180 cells in vivo and to make them obtain multidrug resistance. The results in vitro demonstrated that GBEE could significantly increase the IC50 of DDP on S180 MDR cells, increase the accumulation of Adriamycin (ADR) and rhodamine 123 (Rho 123), and reduce the efflux of Rho 123 of S180 MDR cells. The results from the in vivo treatment with a combination of GBEE and DDP to S180 MDR ascites tumor in mice demonstrated that each dose of GBEE could effectively reverse the drug-resistance of S180 MDR cells to DDP in order to extend the survival time of mice with ascite tumors and inhibit tumor growth in solid tumor mice. In addition, GBEE effectively inhibited the expression of MDR-1 mRNA and multidrug resistance-associated protein-1 mRNA in S180 MDR cells of ascites tumor in mice and improved the expression levels of cytokines, including interleukin (IL)-3, IL-18 and interferon-γ in the blood serum of S180 MDR tumor-bearing mice. The present study showed that the mechanism of GBEE reversal of MDR may be associated with the inhibition of the functional activity of P-glycoprotein, the downregulation of drug resistance related gene expression of S180 MDR cells and the improvement of the production of related serum cytokines of S180 MDR tumor mice. PMID:27698692

  8. Cytotoxicity and apoptosis induced by alfalfa (Medicago sativa) leaf extracts in sensitive and multidrug-resistant tumor cells.

    PubMed

    Gatouillat, Grégory; Magid, Abdulmagid Alabdul; Bertin, Eric; Okiemy-Akeli, Marie-Genevieve; Morjani, Hamid; Lavaud, Catherine; Madoulet, Claudie

    2014-01-01

    Alfalfa (Medicago sativa) has been used to cure a wide variety of ailments. However, only a few studies have reported its anticancer effects. In this study, extracts were obtained from alfalfa leaves and their cytotoxic effects were assessed on several sensitive and multidrug-resistant tumor cells lines. Using the mouse leukaemia P388 cell line and its doxorubicin-resistant counterpart (P388/DOX), we showed that the inhibition of cell growth induced by alfalfa leaf extracts was mediated through the induction of apoptosis, as evidenced by DNA fragmentation analysis. The execution of programmed cell death was achieved via the activation of caspase-3, leading to PARP cleavage. Fractionation of toluene extract (To-1), the most active extract obtained from crude extract, led to the identification of 3 terpene derivatives and 5 flavonoids. Among them, (-)-medicarpin, (-)-melilotocarpan E, millepurpan, tricin, and chrysoeriol showed cytotoxic effects in P388 as well as P388/DOX cells. These results demonstrate that alfalfa leaf extract may have interesting potential in cancer chemoprevention and therapy.

  9. BRCA2-deficient sarcomatoid mammary tumors exhibit multidrug resistance.

    PubMed

    Jaspers, Janneke E; Sol, Wendy; Kersbergen, Ariena; Schlicker, Andreas; Guyader, Charlotte; Xu, Guotai; Wessels, Lodewyk; Borst, Piet; Jonkers, Jos; Rottenberg, Sven

    2015-02-15

    Pan- or multidrug resistance is a central problem in clinical oncology. Here, we use a genetically engineered mouse model of BRCA2-associated hereditary breast cancer to study drug resistance to several types of chemotherapy and PARP inhibition. We found that multidrug resistance was strongly associated with an EMT-like sarcomatoid phenotype and high expression of the Abcb1b gene, which encodes the drug efflux transporter P-glycoprotein. Inhibition of P-glycoprotein could partly resensitize sarcomatoid tumors to the PARP inhibitor olaparib, docetaxel, and doxorubicin. We propose that multidrug resistance is a multifactorial process and that mouse models are useful to unravel this.

  10. Overexpression of the multidrug resistance-associated protein (MRP1) in human heavy metal-selected tumor cells.

    PubMed

    Vernhet, L; Courtois, A; Allain, N; Payen, L; Anger, J P; Guillouzo, A; Fardel, O

    1999-01-29

    Cellular and molecular mechanisms involved in the resistance to cytotoxic heavy metals remain largely to be characterized in mammalian cells. To this end, we have analyzed a metal-resistant variant of the human lung cancer GLC4 cell line that we have selected by a step-wise procedure in potassium antimony tartrate. Antimony-selected cells, termed GLC4/Sb30 cells, poorly accumulated antimony through an enhanced cellular efflux of metal, thus suggesting up-regulation of a membrane export system in these cells. Indeed, GLC4/Sb30 cells were found to display a functional overexpression of the multidrug resistance-associated protein MRP1, a drug export pump, as demonstrated by Western blotting, reverse transcriptase-polymerase chain reaction and calcein accumulation assays. Moreover, MK571, a potent inhibitor of MRP1 activity, was found to markedly down-modulate resistance of GLC4/Sb30 cells to antimony and to decrease cellular export of the metal. Taken together, our data support the conclusion that overexpression of functional MRP1 likely represents one major mechanism by which human cells can escape the cytotoxic effects of heavy metals.

  11. Inhibitory effect of steroidal alkaloids on drug transport and multidrug resistance in human cancer cells.

    PubMed

    Lavie, Y; Harel-Orbital, T; Gaffield, W; Liscovitch, M

    2001-01-01

    Intrinsic or acquired resistance of tumor cells to multiple cytotoxic drugs (multidrug resistance MDR) is a major cause of failure of cancer chemotherapy. MDR is often caused by elevated expression of drug transporters such as P-glycoprotein (P-gp) or multidrug resistance protein (MRP). A number of compounds, termed chemosensitizers, have little or no cytotoxic action of their own, but inhibit (P-gp) or MRP-mediated drug export and are capable of sensitizing MDR cells to the cytotoxic effects of chemotherapeutic drugs. Here we examined the ability of steroidal alkaloids of plant origin, namely the Veratrum sp. alkaloid cyclopamine and the Lycopersicon sp. alkaloid tomatidine, to act as potent and effective chemosensitizers in multidrug resistant tumor cells. Drug uptake was determined by measuring accumulation of tetramethylrosamine in multidrug resistant NCI AdrR human adenocarcinoma cells. Resistance to adriamycin and vinblastine was determined by utilizing the MTT cell survival assay. Cyclopamine and tomatidine elevate tetramethylrosamine uptake by NCI AdrR cells and sensitize the cells to the cytotoxic action of adriamycin and vinblastine. In both cases these agents are comparable in patency and efficacy to verapamil, a reversal agent commonly used in MDR research. It is concluded that steroidal alkaloids of plant origin act as inhibitors of P-gp-mediated drug transport and multidrug resistance and therefore may serve as chemosensitizers in combination chemotherapy with conventional cytotoxic drugs for treating multidrug resistant cancer.

  12. Nanodrug delivery in reversing multidrug resistance in cancer cells

    PubMed Central

    Kapse-Mistry, Sonali; Govender, Thirumala; Srivastava, Rohit; Yergeri, Mayur

    2014-01-01

    Different mechanisms in cancer cells become resistant to one or more chemotherapeutics is known as multidrug resistance (MDR) which hinders chemotherapy efficacy. Potential factors for MDR includes enhanced drug detoxification, decreased drug uptake, increased intracellular nucleophiles levels, enhanced repair of drug induced DNA damage, overexpression of drug transporter such as P-glycoprotein(P-gp), multidrug resistance-associated proteins (MRP1, MRP2), and breast cancer resistance protein (BCRP). Currently nanoassemblies such as polymeric/solid lipid/inorganic/metal nanoparticles, quantum dots, dendrimers, liposomes, micelles has emerged as an innovative, effective, and promising platforms for treatment of drug resistant cancer cells. Nanocarriers have potential to improve drug therapeutic index, ability for multifunctionality, divert ABC-transporter mediated drug efflux mechanism and selective targeting to tumor cells, cancer stem cells, tumor initiating cells, or cancer microenvironment. Selective nanocarrier targeting to tumor overcomes dose-limiting side effects, lack of selectivity, tissue toxicity, limited drug access to tumor tissues, high drug doses, and emergence of multiple drug resistance with conventional or combination chemotherapy. Current review highlights various nanodrug delivery systems to overcome mechanism of MDR by neutralizing, evading, or exploiting the drug efflux pumps and those independent of drug efflux pump mechanism by silencing Bcl-2 and HIF1α gene expressions by siRNA and miRNA, modulating ceramide levels and targeting NF-κB. “Theragnostics” combining a cytotoxic agent, targeting moiety, chemosensitizing agent, and diagnostic imaging aid are highlighted as effective and innovative systems for tumor localization and overcoming MDR. Physical approaches such as combination of drug with thermal/ultrasound/photodynamic therapies to overcome MDR are focused. The review focuses on newer drug delivery systems developed to overcome

  13. Phorbol esters induce multidrug resistance in human breast cancer cells

    SciTech Connect

    Fine, R.L.; Patel, J.; Chabner, B.A.

    1988-01-01

    Mechanisms responsible for broad-based resistance to antitumor drugs derived from natural products (multidrug resistance) are incompletely understood. Agents known to reverse the multidrug-resistant phenotype (verapamil and trifluoperazine) can also inhibit the activity of protein kinase C. When the authors assayed human breast cancer cell lines for protein kinase C activity, they found that enzyme activity was 7-fold higher in the multidrug-resistance cancer cells compared with the control, sensitive parent cells. Exposure of drug-sensitive cells to the phorbol ester phorbol 12,13-dibutyate (P(BtO)/sub 2/) led to an increase in protein kinase C activity and induced a drug-resistance phenotype, whereas exposure of drug-resistant cells to P(BtO)/sub 2/ further increased drug resistance. In sensitive cells, this increased resistance was accomplished by a 3.5-fold increased phosphorylation of a 20-kDa particulate protein and a 35-40% decreased intracellular accumulation of doxorubicin and vincristine. P(BtO)/sub 2/ induced resistance to agents involved in the multidrug-resistant phenotype (doxorubicin and vincristine) but did not affect sensitivity to an unrelated alkylating agent (melphalan). The increased resistance was partially or fully reversible by the calcium channel blocker verapamil and by the calmodulin-antagonist trifluoperazine. These data suggest that stimulation of protein kinase C playus a role in the drug-transport changes in multidrug-resistant cells. This may occur through modulation of an efflux pump by protein phosphorylation.

  14. Nanomedicinal strategies to treat multidrug-resistant tumors: current progress

    PubMed Central

    Dong, Xiaowei; Mumper, Russell J

    2010-01-01

    Multidrug resistance (MDR) is a major impediment to the success of cancer chemotherapy. P-glycoprotein is an important and the best-known membrane transporter involved in MDR. Several strategies have been used to address MDR, especially P-glycoprotein-mediated drug resistance in tumors. However, clinical success has been limited, largely due to issues regarding lack of efficacy and/or safety. Nanoparticles have shown the ability to target tumors based on their unique physical and biological properties. To date, nanoparticles have been investigated primarily to address P-glycoprotein and the observed improved anticancer efficacy suggests that nanomedicinal strategies provide a new opportunity to overcome MDR. This article focuses on nanotechnology-based formulations and current nanomedicine approaches to address MDR in tumors and discusses the proposed mechanisms of action. PMID:20528455

  15. Promoter methylation patterns of ABCB1, ABCC1 and ABCG2 in human cancer cell lines, multidrug-resistant cell models and tumor, tumor-adjacent and tumor-distant tissues from breast cancer patients

    PubMed Central

    Spitzwieser, Melanie; Pirker, Christine; Koblmüller, Bettina; Pfeiler, Georg; Hacker, Stefan; Berger, Walter; Heffeter, Petra; Cichna-Markl, Margit

    2016-01-01

    Overexpression of ABCB1, ABCC1 and ABCG2 in tumor tissues is considered a major cause of limited efficacy of anticancer drugs. Gene expression of ABC transporters is regulated by multiple mechanisms, including changes in the DNA methylation status. Most of the studies published so far only report promoter methylation levels for either ABCB1 or ABCG2, and data on the methylation status for ABCC1 are scarce. Thus, we determined the promoter methylation patterns of ABCB1, ABCC1 and ABCG2 in 19 human cancer cell lines. In order to contribute to the elucidation of the role of DNA methylation changes in acquisition of a multidrug resistant (MDR) phenotype, we also analyzed the promoter methylation patterns in drug-resistant sublines of the cancer cell lines GLC-4, SW1573, KB-3-1 and HL-60. In addition, we investigated if aberrant promoter methylation levels of ABCB1, ABCC1 and ABCG2 occur in tumor and tumor-surrounding tissues from breast cancer patients. Our data indicates that hypomethylation of the ABCC1 promoter is not cancer type-specific but occurs in cancer cell lines of different origins. Promoter methylation was found to be an important mechanism in gene regulation of ABCB1 in parental cancer cell lines and their drug-resistant sublines. Overexpression of ABCC1 in MDR cell models turned out to be mediated by gene amplification, not by changes in the promoter methylation status of ABCC1. In contrast to the promoters of ABCC1 and ABCG2, the promoter of ABCB1 was significantly higher methylated in tumor tissues than in tumor-adjacent and tumor-distant tissues from breast cancer patients. PMID:27689338

  16. An Autocrine Cytokine/JAK/STAT-Signaling Induces Kynurenine Synthesis in Multidrug Resistant Human Cancer Cells

    PubMed Central

    Campia, Ivana; Buondonno, Ilaria; Castella, Barbara; Rolando, Barbara; Kopecka, Joanna; Gazzano, Elena; Ghigo, Dario; Riganti, Chiara

    2015-01-01

    Background Multidrug resistant cancer cells are hard to eradicate for the inefficacy of conventional anticancer drugs. Besides escaping the cytotoxic effects of chemotherapy, they also bypass the pro-immunogenic effects induced by anticancer drugs: indeed they are not well recognized by host dendritic cells and do not elicit a durable anti-tumor immunity. It has not yet been investigated whether multidrug resistant cells have a different ability to induce immunosuppression than chemosensitive ones. We addressed this issue in human and murine chemosensitive and multidrug resistant cancer cells. Results We found that the activity and expression of indoleamine 2,3-dioxygenase 1 (IDO1), which catalyzes the conversion of tryptophan into the immunosuppressive metabolite kynurenine, was higher in all the multidrug resistant cells analyzed and that IDO1 inhibition reduced the growth of drug-resistant tumors in immunocompetent animals. In chemoresistant cells the basal activity of JAK1/STAT1 and JAK1/STAT3 signaling was higher, the STAT3 inhibitor PIAS3 was down-regulated, and the autocrine production of STAT3-target and IDO1-inducers cytokines IL-6, IL-4, IL-1β, IL-13, TNF-α and CD40L, was increased. The disruption of the JAK/STAT signaling lowered the IDO1 activity and reversed the kynurenine-induced pro-immunosuppressive effects, as revealed by the restored proliferation of T-lymphocytes in STAT-silenced chemoresistant cells. Conclusions Our work shows that multidrug resistant cells have a stronger immunosuppressive attitude than chemosensitive cells, due to the constitutive activation of the JAK/STAT/IDO1 axis, thus resulting chemo- and immune-evasive. Disrupting this axis may significantly improve the efficacy of chemo-immunotherapy protocols against resistant tumors. PMID:25955018

  17. Inhibition of Snail Family Transcriptional Repressor 2 (SNAI2) Enhances Multidrug Resistance of Hepatocellular Carcinoma Cells

    PubMed Central

    Fu, Rong-Jie; Lv, Ya-Ping; Jin, Wei; Meng, Chao; Chen, Guo-Qiang; Huang, Lei

    2016-01-01

    China accounts for almost half of the total number of liver cancer cases and deaths worldwide, and hepatocellular carcinoma (HCC) is the most primary liver cancer. Snail family transcriptional repressor 2 (SNAI2) is known as an epithelial to mesenchymal transition-inducing transcription factor that drives neoplastic epithelial cells into mesenchymal phenotype. However, the roles of endogenous SNAI2 remain controversial in different types of malignant tumors. Herein, we surprisingly identify that anchorage-independent growth, including the formation of tumor sphere and soft agar colony, is significantly increased when SNAI2 expression is inhibited by shRNAs in HCC cells. Suppression of SNAI2 suffices to up-regulate several cancer stem genes. Although unrelated to the metastatic ability, SNAI2 inhibition does increase the efflux of Hoechst 33342 and enhance multidrug resistance in vitro and in vivo. In agreement with this data, we demonstrate for the first time that decreasing SNAI2 level can transcriptionally upregulate several ATP binding cassette (ABC) transporter genes such as ABCB1. Moreover, ABC transporters’ inhibitor verapamil can rescue the multidrug resistance induced by SNAI2 inhibition. Our results implicate that SNAI2 behaves as a tumor suppressor by inhibiting multidrug resistance via suppressing ABC transporter genes in HCC cells. PMID:27760172

  18. Metformin reverses multidrug resistance in human hepatocellular carcinoma Bel-7402/5-fluorouracil cells

    PubMed Central

    LING, SUNBIN; TIAN, YU; ZHANG, HAIQUAN; JIA, KAIQI; FENG, TINGTING; SUN, DEGUANG; GAO, ZHENMING; XU, FEI; HOU, ZHAOYUAN; LI, YAN; WANG, LIMING

    2014-01-01

    Metformin exhibits anti-proliferative effects in tumor cells in vitro and in vivo. The present study investigated the ability of metformin to reverse multidrug resistance (MDR) in human hepatocellular carcinoma Bel-7402/5-fluorouracil (5-Fu; Bel/Fu) cells. The synergistic anti-proliferative effect of metformin combined with 5-Fu was evaluated using a Cell Counting kit-8 assay. The variation in apoptotic rates and cell cycle distribution were evaluated using a flow cytometric assay and variations in target gene and protein expression were monitored using reverse transcription-polymerase chain reaction and western blot analysis. The results demonstrated that metformin had a synergistic anti-proliferative effect with 5-Fu in the Bel/Fu cells. The variations in the number of apoptotic cells and distribution of the cell cycle were consistent with the variability in cell viability. Metformin targeted the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway, suppressed the expression of hypoxia-inducible factor-1α (HIF-1α) and transcriptionally downregulated the expression of multidrug resistance protein 1/P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1). Collectively, these findings suggested that metformin may target the AMPK/mTOR/HIF-1α/P-gp and MRP1 pathways to reverse MDR in hepatocellular carcinoma. PMID:25310259

  19. Biodegradable Nanocomplex from Hyaluronic acid and Arginine based Poly(ester amide)s as the Delivery Vehicles for Improved Photodynamic Therapy of Multidrug Resistant Tumor Cells: An In Vitro Study of the Performance of Chlorin e6 Photosensitizer.

    PubMed

    Ji, Ying; Zhao, Jihui; Chu, Chih-Chang

    2016-12-20

    Photodynamic therapy (PDT), which enables the localized therapeutic effect by light irradiation, provides an alternative and complementary modality for the treatment of tumor. However, the aggregation of photosensitizers in acidic microenvironment of tumor and the non-targeted distribution of photosensitizers in normal tissues significantly affect the PDT efficiency. In this study, we developed a biodegradable nanocomplex HA-Arg-PEA from hyaluronic acid (HA) and arginine based poly(ester amide)s (Arg-PEA) as the nano-carrier for chlorin e6 (Ce6). HA enhanced the tumor-specific endocytosis mediated by the overexpression of CD44 receptor. Arg-PEA not only provide electrostatic interaction with HA to form self-assembled nanostructure, but also improve the monomerization of Ce6 at physiological pH as well as mildly acidic pH. The biodegradable characteristic of HA-Arg-PEA nanocomplex enabled the intracellular delivery of Ce6, in which its release and generation of singlet oxygen can be accelerated by enzymatic degradation of the carrier. The in vitro PDT efficiency of Ce6-loaded HA-Arg-PEA nanocomplex was examined in CD44 positive MDA-MB-435/MDR multidrug resistant melanoma cells. CD44-mediated uptake of Ce6-loaded HA-Arg-PEA nanocomplex significantly improved Ce6 level in MDA-MB-435/MDR cells within short incubation time, and the PDT efficiency in inhibiting multidrug resistant tumor cells was also enhanced at higher Ce6 concentrations. This article is protected by copyright. All rights reserved.

  20. A peptide derived from phage display library exhibits anti-tumor activity by targeting GRP78 in gastric cancer multidrug resistance cells.

    PubMed

    Kang, Jianqin; Zhao, Guohong; Lin, Tao; Tang, Shanhong; Xu, Guanghui; Hu, Sijun; Bi, Qian; Guo, Changcun; Sun, Li; Han, Shuang; Xu, Qian; Nie, Yongzhan; Wang, Biaoluo; Liang, Shuhui; Ding, Jie; Wu, Kaichun

    2013-10-10

    Multidrug resistance (MDR) remains a significant challenge to the clinical treatment of gastric cancer (GC). In the present study, using a phage display approach combined with MTT assays, we screened a specific peptide GMBP1 (Gastric cancer MDR cell-specific binding peptide), ETAPLSTMLSPY, which could bind to the surface of GC MDR cells specifically and reverse their MDR phenotypes. Immunocytochemical staining showed that the potential receptor of GMBP1 was located at the membrane and cytoplasm of MDR cells. In vitro and in vivo drug sensitivity assays, FACS analysis and Western blotting confirmed that GMBP1 was able to re-sensitize MDR cells to chemical drugs. Western blotting and proteomic approaches were used to screen the receptor of GMBP1, and GRP78, a MDR-related protein, was identified as a receptor of GMBP1. This result was further supported by immunofluoresence microscopy and Western blot. Additionally, Western blotting demonstrated that pre-incubation of GMBP1 in MDR cells greatly diminished MDR1, Bcl-2 and GRP78 expression but increased the expression of Bax, whereas downregulation of GRP78, function as a receptor and directly target for GMBP1, only inhibited MDR1 expression. Our findings suggest that GMBP1 could re-sensitize GC MDR cells to a variety of chemotherapeutic agents and this role might be mediated partly through down-regulating GRP78 expression and then inhibiting MDR1 expression. These findings indicate that peptide GMBP1 likely recognizes a novel GRP78 receptor and mediates cellular activities associated with the MDR phenotype, which provides new insight into research on the management of MDR in gastric cancer cells.

  1. Effects of standard chemotherapy on tumor growth and regulation of multidrug resistance genes and proteins in childhood rhabdomyosarcoma.

    PubMed

    Seitz, Guido; Warmann, Steven W; Vokuhl, Christian O; Heitmann, Heike; Treuner, Claudia; Leuschner, Ivo; Fuchs, Jörg

    2007-05-01

    The prognosis of rhabdomyosarcoma (RMS) in advanced stages is still sobering. Therapy is limited due to local tumor recurrence, development of metastases and multidrug resistance. The aim of this study was to investigate the development of multidrug resistance in cell lines and in xenografts of alveolar and embryonal RMS treated according to the German Soft Tissue Sarcoma Study (CWS). Alveolar and embryonal RMS cell lines were treated with Vincristine, Topotecan, Carboplatin, Actinomycin D, or Ifosfamide. Expression levels of resistance-associated genes were assessed using Real time-PCR. Nude mice (NMRI nu/nu, n = 10 per group) underwent xenotransplantation of human embryonal or alveolar RMS. Animals were treated with standard chemotherapeutic drugs Vincristine, Topotecan, Carboplatin, Actinomycin D, or Ifosfamide according to treatment schedules of the CWS-study. Tumor sizes were measured and relative tumor volumes were calculated. Animals were sacrificed after 20 days and standard histology, Real-time-PCR for MDR1-, MRP-, LRP- and MDM2-gene as well as immunohistochemistry for MDR1-, LRP-, and MRP-protein were performed. In the cell lines, an up-regulation of MDR-1 gene was found in alveolar rhabdomyosarcoma. In embryonal rhabdomyosarcoma, an up-regulation of LRP and MRP was found. Standard chemotherapy of alveolar rhabdomyosarcoma resulted in a significant reduction of tumor growth (P < 0.05) in all groups. In embryonal rhabdomyosarcoma strongest effects were found after treatment with Ifosfamide, Vincristine and Carboplatin (P < 0.05). RT-PCR revealed a MDR1-dependent mechanism in alveolar rhabdomyosarcoma. In embryonal rhabdomyosarcoma, MDR1 occurred to a lower degree. Immunohistochemistry revealed correlating expression levels of multidrug resistance-associated proteins. The use of established chemotherapy on human RMS in vivo had strong effects on xenografts compared to their controls. In all cases, there was only a reduction of tumor growth, but not a

  2. Role of multidrug resistance in photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Diddens, Heyke C.

    1992-06-01

    Multidrug resistance in cancer chemotherapy is a well established phenomenon. One of the most common phenotypical changes in acquired or intrinsic multidrug resistance in human tumor cells is the overexpression of the mdrl gene product P-glycoprotein, which acts as an active efflux pump. Increased levels of P-glycoprotein are associated with resistance to a variety of anticancer drugs commonly used in tumor chemotherapy like anthracyclins, vinca- alcaloids, epipodophyllotoxins or actinomycin D. We investigated the efficacy or photodynamic therapy in the treatment of tumor cells expressing the multidrug resistance phenotype. Our data show that multidrug resistant cells are highly cross resistant to the phototoxic stain rhodamine 123 but exhibit only low degrees of cross resistance (2 - 3 -folds) to the photosensitizers Photosan-3, Clorin-2, methylene blue and meso-tetra (4- sulfonatophenyl) porphine (TPPS4). Resistance is associated with a decrease in intracellular accumulation of the photosensitizer. Verapamil, a membrane active compound known to enhance drug sensitivity in multidrug resistant cells by inhibition of P-glycoprotein, also increases phototoxicity in multidrug resistant cells. Our results imply that tumors expressing the multidrug resistance phenotype might fail to respond to photochemotherapy with rhodamine 123. On the other hand, multidrug resistance may not play an important role in photodynamic therapy with Photosan-3, Chlorin-2, methylene blue or TPPS4.

  3. Effect of multidrug resistance 1/P-glycoprotein on the hypoxia-induced multidrug resistance of human laryngeal cancer cells.

    PubMed

    Li, Dawei; Zhou, Liang; Huang, Jiameng; Xiao, Xiyan

    2016-08-01

    In a previous study, it was demonstrated that hypoxia upregulated the multidrug resistance (MDR) of laryngeal cancer cells to chemotherapeutic drugs, with multidrug resistance 1 (MDR1)/P-glycoprotein (P-gp) expression also being upregulated. The present study aimed to investigate the role and mechanism of MDR1/P-gp on hypoxia-induced MDR in human laryngeal carcinoma cells. The sensitivity of laryngeal cancer cells to multiple drugs and cisplatin-induced apoptosis was determined by CCK-8 assay and Annexin-V/propidium iodide staining analysis, respectively. The accumulation of rhodamine 123 (Rh123) in the cells served as an estimate of drug accumulation and was evaluated by flow cytometry (FCM). MDR1/P-gp expression was inhibited using interference RNA, and the expression of the MDR1 gene was analyzed using reverse transcription-quantitative polymerase chain reaction and western blotting. As a result, the sensitivity to multiple chemotherapeutic agents and the apoptosis rate of the hypoxic laryngeal carcinoma cells increased following a decrease in MDR1/P-gp expression (P<0.05). Additionally, FCM analysis of fluorescence intensity indicated that the downregulated expression of MDR1/P-gp markedly increased intracellular Rh123 accumulation (P<0.05). Such results suggest that MDR1/P-gp serves an important role in regulating hypoxia-induced MDR in human laryngeal carcinoma cells through a decrease in intracellular drug accumulation.

  4. ROS-triggered and regenerating anticancer nanosystem: an effective strategy to subdue tumor's multidrug resistance.

    PubMed

    Su, Zhigui; Chen, Minglei; Xiao, Yanyu; Sun, Minjie; Zong, Li; Asghar, Sajid; Dong, Mei; Li, Huipeng; Ping, Qineng; Zhang, Can

    2014-12-28

    Drug delivery strategies utilizing tumor microenvironment are recognized as a critical doorway to overcome multidrug resistance (MDR). However, the variability of tumor microenvironment at different disease stages would definitely minimize stimuli generation and eventually the therapeutic effects of these stimuli sensitive systems. Herein, we report a unique reactive oxygen species (ROS) triggered nanosystem that can replenish the ROS upon disassembly to maintain its high level. This was accomplished by a new amphiphilic polymer (TBH) composed of D-α-tocopherol polyethylene glycol 1000 succinate (TPGS), hyaluronic acid (HA) and arylboronic ester. As a linker of TPGS to HA, arylboronic ester could efficiently degrade in response to ROS resulting in dismantling of nanosystem followed by rapid release of TPGS. Owing to ROS inducing activity of TPGS with mitochondrial respiratory complex II, ROS regeneration was observed for TBH nanosystem both in MCF-7/ADR cells and tumor tissues xenografted with MCF-7/ADR cells. Furthermore, doxorubicin-loaded TBH nanosystem (DOX-TBH) revealed higher drug cytotoxicity due to enhanced retention effect on account of ROS triggered DOX release and P-gp inhibitory mechanism of TPGS. Moreover, HA significantly improved tumor targeting capability of DOX-TBH, while ROS based triggering and regenerating mechanism lead to marked inhibition of the tumor growth in the xenograft MCF-7/ADR tumor-bearing nude mice.

  5. The Role of Cell Density and Intratumoral Heterogeneity in Multidrug Resistance

    PubMed Central

    Lavi, Orit; Greene, James M.; Levy, Doron; Gottesman, Michael M.

    2016-01-01

    Recent data have demonstrated that cancer drug resistance reflects complex biological factors including tumor heterogeneity, varying growth, differentiation, apoptosis pathways, and cell density. As a result, there is a need to find new ways to incorporate these complexities in the mathematical modeling of multidrug resistance. Here, we derive a novel structured population model that describes the behavior of cancer cells under selection with cytotoxic drugs. Our model is designed to estimate intratumoral heterogeneity as a function of the resistance level and time. This updated model of the multidrug resistance problem integrates both genetic and epigenetic changes, density-dependence, and intratumoral heterogeneity. Our results suggest that treatment acts as a selection process, while genetic/epigenetic alterations rates act as a diffusion process. Application of our model to cancer treatment suggests that reducing alteration rates as a first step in treatment causes a reduction in tumor heterogeneity, and may improve targeted therapy. The new insight provided by this model could help to dramatically change the ability of clinical oncologists to design new treatment protocols and analyze the response of patients to therapy. Major Findings We suggest that chemotherapeutic treatment acts as a selection process in the effective drug concentrations range, while genetic/epigenetic alterations act as a diffusion process that results in trait spread based on different stress signals. Application of our model to cancer treatment suggests that reducing the alteration rate as a first step in treatment causes a reduction in tumor heterogeneity, and may improve targeted therapy. PMID:24163380

  6. Sinomenine reverses multidrug resistance in bladder cancer cells via P-glycoprotein-dependent and independent manners.

    PubMed

    Chen, Yule; Zhang, Linlin; Lu, Xinlan; Wu, Kaijie; Zeng, Jin; Gao, Yang; Shi, Qi; Wang, Xinyang; Chang, Luke S; He, Dalin

    2014-01-01

    P-Glycoprotein-mediated multidrug resistance is a frequent event during chemotherapy and a key obstacle for bladder cancer therapy. Search for strategies to reverse multidrug resistance is a promising approach to improve the management of bladder cancer. In the present study, we reported a novel P-glycoprotein-mediated multidrug resistant cell model 253J/DOX, which was generated from human bladder cancer 253J cell line. Furthermore, we found that the multidrug resistant phenotype of 253J/DOX cells could be overcome by sinomenine, an alkaloid derived from the stem of Sinomenium acutum. Mechanistically, the chemosensitive effect by sinomenine was mediated by down-regulating P-glycoprotein expression, as well as triggering apoptotic pathways. The chemosensitive effect of sinomenine may make it a prime candidate agent to target bladder cancer.

  7. Multidrug-resistance proteins are weak tumor associated antigens for colorectal carcinoma

    PubMed Central

    2011-01-01

    Background Multidrug resistance (MDR) is a clinically, highly relevant phenomenon. Under chemotherapy many tumors show an increasing resistance towards the applied substance(s) and to a certain extent also towards other agents. An important molecular cause of this phenomenon is an increased expression of transporter proteins. The functional relationship between high expression levels and chemotherapy resistance makes these MDR and MRP (MDR related protein) proteins to interesting therapeutic targets. We here wanted to systematically analyze, whether these proteins are tumor specific antigens which could be targeted immunologically. Results Using the reverse immunology approach, 30 HLA-A2.1 restricted MDR and MRP derived peptides (MDP) were selected. Stimulated T cell lines grew well and mainly contained activated CD8+ cells. Peptide specificity and HLA-A2.1 restriction were proven in IFN-γ-ELISpot analyses and in cytotoxicity tests against MDP loaded target cells for a total of twelve peptides derived from MDR-1, MDR-3, MRP-1, MRP-2, MRP-3 and MRP-5. Of note, two of these epitopes are shared between MDR-1 and MDR-3 as well as MRP-2 and MRP-3. However, comparably weak cytotoxic activities were additionally observed against HLA-A2.1+ tumor cells even after upregulation of MDR protein expression by in vitro chemotherapy. Conclusions Taken together, these data demonstrate that human T cells can be sensitised towards MDPs and hence, there is no absolute immunological tolerance. However, our data also hint towards rather low endogenous tumor cell processing and presentation of MDPs in the context of HLA-A2.1 molecules. Consequently, we conclude that MDR and MRP proteins must be considered as weak tumor specific antigens-at least for colorectal carcinoma. Their direct contribution to therapy-failure implies however, that it is worth to further pursue this approach. PMID:21740599

  8. Role of uL3 in Multidrug Resistance in p53-Mutated Lung Cancer Cells

    PubMed Central

    Russo, Annapina; Saide, Assunta; Smaldone, Silvia; Faraonio, Raffaella; Russo, Giulia

    2017-01-01

    Cancer is one of the most common causes of death among adults. Chemotherapy is crucial in determining patient survival and quality of life. However, the development of multidrug resistance (MDR) continues to pose a significant challenge in the management of cancer. In this study, we analyzed the role of human ribosomal protein uL3 (formerly rpL3) in multidrug resistance. Our studies revealed that uL3 is a key determinant of multidrug resistance in p53-mutated lung cancer cells by controlling the cell redox status. We established and characterized a multidrug resistant Calu-6 cell line. We found that uL3 down-regulation correlates positively with multidrug resistance. Restoration of the uL3 protein level re-sensitized the resistant cells to the drug by regulating the reactive oxygen species (ROS) levels, glutathione content, glutamate release, and cystine uptake. Chromatin immunoprecipitation experiments and luciferase assays demonstrated that uL3 coordinated the expression of stress-response genes acting as transcriptional repressors of solute carrier family 7 member 11 (xCT) and glutathione S-transferase α1 (GST-α1), independently of Nuclear factor erythroid 2-related factor 2 (Nrf2). Altogether our results describe a new function of uL3 as a regulator of oxidative stress response genes and advance our understanding of the molecular mechanisms underlying multidrug resistance in cancers. PMID:28273808

  9. Nanoparticle-mediated drug delivery to tumor neovasculature to combat P-gp expressing multidrug resistant cancer.

    PubMed

    Bai, Fan; Wang, Chao; Lu, Qin; Zhao, Mei; Ban, Fu-Qiang; Yu, De-Hong; Guan, Ying-Yun; Luan, Xin; Liu, Ya-Rong; Chen, Hong-Zhuan; Fang, Chao

    2013-08-01

    Anticancer drug resistance is a common intractable obstacle in clinical cancer chemotherapy. Here, we hypothesize that antiangiogenic cancer therapy through the targeted delivery of antiangiogenic agents to the tumor endothelial cells (EC), not the resistant cancer cells, may have the potential of combating multidrug resistant cancer. The K237 peptide-conjugated paclitaxel loaded nanoparticles (K237-PTX-NP), which can target KDR receptors highly expressed in the tumor vasculature, were fabricated for this investigation and the human colorectal adenocarcinoma HCT-15 with naturally expressed P-gp on the cell surface was adopted as the resistant tumor model. The human umbilical vein endothelial cells (HUVEC, a classical cell model mimicking tumor EC) were much more sensitive, in the cytotoxicity and apoptosis test, to K237-PTX-NP than Taxol and non-targeted PTX-NP. The enhanced antiangiogenic feature of K237-PTX-NP can be ascribed to the active internalization mediated by the interaction of K237 and KDR specifically highly expressed on the HUVEC, and the significantly extended intracellular drug retention. The tumor vessel targeting of K237-PTX-NP led to increased nanoparticle accumulation in HCT-15 tumors, and more importantly, induced significant apoptosis of tumor vascular EC and necrosis of tumor tissues. Low dose paclitaxel formulated in K237-PTX-NP (1 mg/kg) achieved significant anticancer efficacy of inhibiting the growth of HCT-15 tumors, but the same efficacy could be only obtained with 8 fold dose paclitaxel (8 mg/kg) in Taxol plus XR9576, a potent P-gp inhibitor. The anticancer efficacy of K237-PTX-NP was well related with the improved antiangiogenic effect shown in the dramatically decreased intratumoral microvessel density and pronouncedly increased apoptotic tumor cells, and such approach did not lead to obvious toxicity in the mice. These results suggest that the nanoparticles targeting drug to tumor neovasculature may be a promising strategy for the

  10. Human SPF45, a Splicing Factor, Has Limited Expression in Normal Tissues, Is Overexpressed in Many Tumors, and Can Confer a Multidrug-Resistant Phenotype to Cells

    PubMed Central

    Sampath, Janardhan; Long, Pandy R.; Shepard, Robert L.; Xia, Xiaoling; Devanarayan, Viswanath; Sandusky, George E.; Perry, William L.; Dantzig, Anne H.; Williamson, Mark; Rolfe, Mark; Moore, Robert E.

    2003-01-01

    Our effort to identify novel drug-resistant genes in cyclophosphamide-resistant EMT6 mouse mammary tumors led us to the identification of SPF45. Simultaneously, other groups identified SPF45 as a component of the spliceosome that is involved in alternative splicing. We isolated the human homologue and examined the normal human tissue expression, tumor expression, and the phenotype caused by overexpression of human SPF45. Our analyses revealed that SPF45 is expressed in many, but not all, normal tissues tested with predominant expression in normal ductal epithelial cells of the breast, liver, pancreas, and prostate. Our analyses using tissue microarrays and sausages of tumors indicated that SPF45 is highly expressed in numerous carcinomas including bladder, breast, colon, lung, ovarian, pancreatic, and prostate. Interestingly, this study revealed that overexpression of SPF45 in HeLa, a cervical carcinoma cell line, resulted in drug resistance to doxorubicin and vincristine, two chemotherapeutic drugs commonly used in cancer. To our knowledge, this is the first study showing tumor overexpression of an alternate splicing factor resulting in drug resistance. PMID:14578179

  11. Establishment of a human hepatoma multidrug resistant cell line in vitro

    PubMed Central

    Zhou, Yuan; Ling, Xian-Long; Li, Shi-Wei; Li, Xin-Qiang; Yan, Bin

    2010-01-01

    AIM: To establish a multidrug-resistant hepatoma cell line (SK-Hep-1), and to investigate its biological characteristics. METHODS: A highly invasive SK-Hep-1 cell line of human hepatocellular carcinoma, also known as malignant hepatoma was incubated with a high concentration of cisplatin (CDDP) to establish a CDDP-resistant cell subline (SK-Hep-1/CDDP). The 50% inhibitory dose (IC50) values and the resistance indexes [(IC50 SK-Hep-1/CDDP)/(IC50 SK-Hep-1)] for other chemotherapeutic agents and the growth curve of cells were all evaluated using cell counting kit-8 assays. The distribution of the cell cycles were detected by flow cytometry. Expression of acquired multidrug resistance P-glycoprotein (MDR1, ABCB1) and multidrug resistance-associated protein 1 (MRP1, ABCC1) was compared with that in parent cells by Western blotting and immunofluorescence combined with laser scanning confocal microscopy. RESULTS: The SK-Hep-1/CDDP cells (IC50 = 70.61 ± 1.06 μg/mL) was 13.76 times more resistant to CDDP than the SK-Hep-1 cells (IC50 = 5.13 ± 0.09 μg/mL), and CDDP-resistant cells also demonstrated cross-resistance to many anti-tumor agents such as doxorubicin, 5-fluorouracil and vincristine. Similar morphologies were determined in both SK-Hep-1 and SK-Hep-1/CDDP groups. The cell cycle distribution of the SK-Hep-1/CDDP cell line exhibited a significantly increased percentage of cells in S (42.2% ± 2.65% vs 27.91% ± 2.16%, P < 0.01) and G2/M (20.67% ± 5.69% vs 12.14% ± 3.36%, P < 0.01) phases in comparison with SK-Hep-1 cells, while the percentage of cells in the G0/G1 phase decreased (37.5% ± 5.05% vs 59.83% ± 3.28%, P < 0.01). The levels of MDR1 and MRP1 were overexpressed in the SK-Hep-1/CDDP cells exhibiting the MDR phenotype. CONCLUSION: Multiple drug resistance of multiple drugs in the human hepatoma cell line SK-Hep-1/CDDP was closely related to the overexpression of MDR1 and MRP1. PMID:20458768

  12. Expression of the multidrug resistance gene product (P-glycoprotein) in human normal and tumor tissues.

    PubMed

    Cordon-Cardo, C; O'Brien, J P; Boccia, J; Casals, D; Bertino, J R; Melamed, M R

    1990-09-01

    We have characterized the normal human tissue distribution and tumor expression of the human multidrug resistance gene (MDR1) product P-glycoprotein (Pgp) by immunohistochemical staining of frozen tissue sections of human normal and tumor tissues, using three mouse monoclonal antibodies (MAb) which recognize at least two different epitopes of Pgp. Pgp expression on normal human tissues was detected in specialized epithelial cells with secretory/excretory functions, trophoblasts in the placenta, and on endothelial cells of capillary blood vessels at blood-tissue barrier sites. There were significant differences in the staining patterns of these MAb. Mouse MAb HYB-241 and HYB-612 each recognize an extracellular epitope of Pgp, whereas mouse MAb C219 detects a carboxy terminal intracellular epitope and has recently been reported to crossreact with the MDR3 gene product. HYB-241 and HYB-612 strongly stain endothelial cells and trophoblasts, whereas C219 is weakly positive or unreactive on these cells. Likewise, C219 strongly stains the biliary pole of hepatocytes, skeletal and heart muscle fibers, whereas HYB-241 and HYB-612 are unreactive on these cells. Immunopathological studies were performed on a wide variety of human tumors. Pgp expression on human tumors was most commonly detected in colon. renal, and adrenal carcinomas; rarely in lung and gastric carcinomas and certain germ cell tumors; and was undetectable in breast and endometrial carcinomas tested. Few sarcomas and none of the melanomas, neuroblastomas, gliomas, and pheochromocytomas had detectable Pgp expression. Intensity and pattern of staining varied among different cases of a given tumor type; although homogeneous immunoreactivity was observed, heterogeneity of expression in a single histological section was more common. The finding of Pgp expression in a variety of normal tissues with diverse physiological functions suggests that the role of Pgp may not be limited to excretion of xenobiotics. Pgp

  13. Nrf2 pathway regulates multidrug-resistance-associated protein 1 in small cell lung cancer.

    PubMed

    Ji, Lili; Li, Hui; Gao, Pan; Shang, Guoguo; Zhang, Donna D; Zhang, Nong; Jiang, Tao

    2013-01-01

    Although multidrug-resistance-associated protein-1 (MRP1) is a major contributor to multi-drug resistance (MDR), the regulatory mechanism of Mrp1 still remains unclear. Nrf2 is a transcription factor that regulates cellular defense response through antioxidant response elements (AREs) in normal tissues. Recently, Nrf2 has emerged as an important contributor to chemo-resistance in tumor tissues. In the present study, the role of Nrf2-ARE pathway on regulation of Mrp1 was investigated. Compared with H69 lung cancer cells, H69AR cells with MDR showed significantly higher Nrf2-ARE pathway activity and expression of Mrp1 as well. When Nrf2 was knocked down in H69AR cells, MRP1's expression decreased accordingly. Moreover, those H69AR cells with reduced Nrf2 level restored sensitivity to chemo-drugs. To explore how Nrf2-ARE pathway regulates Mrp1, the promoter of Mrp1 gene was searched, and two putative AREs--ARE1 and ARE2--were found. Using reporter gene and ChIP assay, both ARE1 and ARE2 showed response to and interaction with Nrf2. In 40 cases of cancer tissues, the expression of Nrf2 and MRP1 was measured by immunohistochemistry (IHC). As the quantitive data of IHC indicated, both Nrf2 and MRP1 showed significantly higher expression in tumor tissue than adjacent non-tumor tissue. And more important, the correlation analysis of the two genes proved that their expression was correlative. Taken together, theses data suggested that Nrf2-ARE pathway is required for the regulatory expression of Mrp1 and implicated Nrf2 as a new therapeutic target for MDR.

  14. A Novel Submicron Emulsion System Loaded with Doxorubicin Overcome Multi-Drug Resistance in MCF-7/ADR Cells

    PubMed Central

    Zhou, W. P.; Hua, H. Y.; Sun, P. C.; Zhao, Y. X.

    2015-01-01

    The purpose of the present study was to develop the Solutol HS15-based doxorubicin submicron emulsion with good stability and overcoming multi-drug resistance. In this study, we prepared doxorubicin submicron emulsion, and examined the stability after autoclaving, the in vitro cytotoxic activity, the intracellular accumulation and apoptpsis of doxorubicin submicron emulsion in MCF-7/ADR cells. The physicochemical properties of doxorubicin submicron emulsion were not significantly affected after autoclaving. The doxorubicin submicron emulsion significantly increased the intracellular accumulation of doxorubicin submicron emulsion and enhanced cytotoxic activity and apoptotic effects of doxorubicin. These results may be correlated to doxorubicin submicron emulsion inhibitory effects on efflux pumps through the progressive release of intracellular free Solutol HS15 from doxorubicin submicron emulsion. Furthermore, these in vitro results suggest that the Solutol HS15-based submicron emulsion may be a potentially useful drug delivery system to circumvent multi-drug resistance of tumor cells. PMID:26664069

  15. Expression of a multidrug-resistance gene in human tumors and tissues

    SciTech Connect

    Fojo, A.T.; Ueda, K.; Slamon, D.J.; Poplack, D.G.; Gottesman, M.M.; Pastan, I.

    1987-01-01

    The identification and cloning of a segment of a human multidrug resistance gene (mdr1) was reported recently. To examine, the molecular basis of one type of multidrug resistance, the authors have prepared RNA from human tumors and normal tissues and measured their content of mdr1 RNA. They find that the mdr1 gene is expressed at a very high level in the adrenal gland; at a high level in the kidney; at intermediate levels in the lung, liver, lower jejunum, colon, and rectum; and at low levels in many other tissues. The mdr1 gene is also expressed in several human tumors, including many but not all tumors derived from the adrenal gland and the colon. In addition, increased expression was detected in a few tumors at the time of relapse following initial chemotherapy. Although controlled clinical studies will be required, the results suggest that measurement of mdr1 RNA may prove to be a valuable tool in the design of chemotherapy protocols.

  16. Multidrug-Resistant Tuberculous Mediastinal Lymphadenitis, with an Esophagomediastinal Fistula, Mimicking an Esophageal Submucosal Tumor.

    PubMed

    Kim, Dongwuk; Kim, Juwon; Lee, Daegeun; Chang, Ha Sung; Joh, Hyunsung; Koh, Won-Jung; Lee, Jun Haeng

    2016-11-01

    Mediastinal tuberculous lymphadenitis rarely mimics esophageal submucosal tumor, particularly in the case of multidrug-resistant tuberculosis (MDR-TB). Herein, we report the case of a 61-year-old woman who visited a local hospital complaining of odynophagia. An initial esophagogastroduodenoscopy revealed an esophageal submucosal tumor, and subsequent chest computed tomography showed subcarinal lymphadenopathy with an esophagomediastinal fistula. The patient was then referred to Samsung Medical Center, and a second esophagogastroduodenoscopy showed deep central ulceration, as well as a suspicious fistula in the esophageal submucosal tumor-like lesion. A biopsy examination of the ulcerative lesion confirmed focal inflammation only. Next, an endobronchial, ultrasound-guided lymph node biopsy was performed, and TB was confirmed. The patient initially began a course of isoniazid, rifampicin, ethambutol, and pyrazinamide. However, after a drug sensitivity test, she was diagnosed with MDR-TB, and second-line anti-TB medications were prescribed. She recovered well subsequently.

  17. Importance of inducible multidrug resistance 1 expression in HL-60 cells resistant to gemtuzumab ozogamicin.

    PubMed

    Matsumoto, Taichi; Jimi, Shiro; Hara, Shuuji; Takamatsu, Yasushi; Suzumiya, Junji; Tamura, Kazuo

    2012-07-01

    Resistance to gemtuzumab ozogamicin (GO) hampers the effective treatment of refractory acute myeloid leukemia (AML). To clarify the mechanism of resistance to GO, HL-60 cells were persistently exposed to GO in order to establish GO-resistant HL-60 (HL-60/GOR) cells. Multidrug resistance 1 (MDR-1) was strongly expressed in HL-60/GOR cells, but not in HL-60 cells. Although withdrawal of GO after the chronic exposure of HL-60/GOR cells to this compound gradually decreased MDR-1 expression to trace levels, reintroducing GO restored high MDR-1 expression in HL-60/GOR cells, but not in HL-60 cells. These results indicate that HL-60/GOR cells acquired the ability to induce MDR-1 expression in response to GO. U0126, a MEK1/2 inhibitor, prevented GO-inducible MDR-1 expression and abrogated GO resistance in HL-60/GOR cells. These results suggest that in the clinical use of GO, inducible MDR-1 expression in tumor cells should be investigated before treatment with GO. If the cells are positive then MEK1/2 inhibitors may be effective in overcoming resistance to GO.

  18. A Multidrug-resistant Engineered CAR T Cell for Allogeneic Combination Immunotherapy

    PubMed Central

    Valton, Julien; Guyot, Valérie; Marechal, Alan; Filhol, Jean-Marie; Juillerat, Alexandre; Duclert, Aymeric; Duchateau, Philippe; Poirot, Laurent

    2015-01-01

    The adoptive transfer of chimeric antigen receptor (CAR) T cell represents a highly promising strategy to fight against multiple cancers. The clinical outcome of such therapies is intimately linked to the ability of effector cells to engraft, proliferate, and specifically kill tumor cells within patients. When allogeneic CAR T-cell infusion is considered, host versus graft and graft versus host reactions must be avoided to prevent rejection of adoptively transferred cells, host tissue damages and to elicit significant antitumoral outcome. This work proposes to address these three requirements through the development of multidrug-resistant T cell receptor αβ-deficient CAR T cells. We demonstrate that these engineered T cells displayed efficient antitumor activity and proliferated in the presence of purine and pyrimidine nucleoside analogues, currently used in clinic as preconditioning lymphodepleting regimens. The absence of TCRαβ at their cell surface along with their purine nucleotide analogues-resistance properties could prevent their alloreactivity and enable them to resist to lymphodepleting regimens that may be required to avoid their ablation via HvG reaction. By providing a basic framework to develop a universal T cell compatible with allogeneic adoptive transfer, this work is laying the foundation stone of the large-scale utilization of CAR T-cell immunotherapies. PMID:26061646

  19. By inhibiting Src, verapamil and dasatinib overcome multidrug resistance via increased expression of Bim and decreased expressions of MDR1 and survivin in human multidrug-resistant myeloma cells.

    PubMed

    Tsubaki, Masanobu; Komai, Makiko; Itoh, Tatsuki; Imano, Motohiro; Sakamoto, Kotaro; Shimaoka, Hirotaka; Takeda, Tomoya; Ogawa, Naoki; Mashimo, Kenji; Fujiwara, Daiichiro; Mukai, Junji; Sakaguchi, Katsuhiko; Satou, Takao; Nishida, Shozo

    2014-01-01

    The calcium channel blocker verapamil inhibits the transport function of multidrug resistance protein 1 (MDR1). Although verapamil acts to reverse MDR in cancer cells, the underlying mechanism remains unclear. In the present study, we investigated the mechanism of reversing MDR by verapamil in anti-cancer drug-resistant multiple myeloma (MM) cell lines. We found that verapamil suppresses MDR1 and survivin expressions and increases Bim expression via suppression of Src activation. Furthermore, dasatinib reversed the drug-resistance of the drug-resistant cell lines. These findings suggest that Src inhibitors are potentially useful as an anti-MDR agent for the treatment of malignant tumor cells.

  20. Toxicity mechanisms of onion (Allium cepa) extracts and compounds in multidrug resistant erythroleukemic cell line.

    PubMed

    Votto, Ana P S; Domingues, Beatriz S; de Souza, Michele M; da Silva Júnior, Flavio M R; Caldas, Sergiane S; Filgueira, Daza M V B; Clementin, Rosilene M; Primel, Ednei G; Vallochi, Adriana L; Furlong, Eliana B; Trindade, Gilma S

    2010-01-01

    Onion (Allium cepa) is being studied as a potential anticancer agent, but little is known regarding its effect in multidrug resistance (MDR) cells. In this work, the cytotoxicity of crude onion extract (OE) and fractioned extract (aqueous, methanolic and ethyl acetate), as well as some onion compounds (quercetin and propyl disulfide) were evaluated in Lucena MDR human erythroleukemic and its K562 parental cell line. The capacity of OE to induce apoptosis and/or necrosis in these cells, the possible participation of oxidative stress and DNA damage were also assessed. Similar sensitivities were obtained for both tumoral cells, however only OE caused significant effects in the cells. In K562 cells, a significant increase of apoptosis was verified while the Lucena cells experienced a significant increase of necrosis. An antioxidant capacity was verified for OE discarding oxidative damage. However, OE provoked similar significant DNA damage in both cell lines. Thus, the OE capacity to overcome the MDR phenotype suggests anti-MDR action of OE.

  1. Unaltered expression of multidrug resistance transporters in polycyclic aromatic hydrocarbon-resistant rat liver cells.

    PubMed

    Payen, L; Courtois, A; Langouët, S; Guillouzo, A; Fardel, O

    2001-01-02

    Rat liver epithelial cells resistant to the chemical carcinogen 3MC, termed F258/3MC cells and generated by long-term exposure of parental F258 cells to the PAH, were characterized, especially with respect to expression of multidrug resistance transporters such as P-glycoprotein, MRP1 and MRP2. F258/3MC cells were found to be cross-resistant to other PAHs such as BP and dimethylbenz(a)anthracene but remained sensitive to known substrates of multidrug resistance efflux pumps such as doxorubicin and vincristine. They did not display either decreased cellular PAH accumulation or increased PAH efflux. In addition, P-glycoprotein and MRP2 mRNA levels were not, or only barely detected, in F258/3MC cells and in their parental counterparts whereas these PAH-resistant and sensitive cells showed closed levels of MRP1 mRNAs and activity. Moreover, P-gp- and MRP1-overexpressing cells were shown to display similar accumulation and efflux of BP than those found in P-gp- and MRP1-negative control cells. These data therefore suggest that multidrug resistance transporters do not contribute to PAH resistance in PAH-selected liver cells.

  2. High heterogeneity of plasma membrane microfluidity in multidrug-resistant cancer cells

    NASA Astrophysics Data System (ADS)

    Boutin, Céline; Roche, Yann; Millot, Christine; Deturche, Régis; Royer, Pascal; Manfait, Michel; Plain, Jérôme; Jeannesson, Pierre; Millot, Jean-Marc; Jaffiol, Rodolphe

    2009-05-01

    Diffusion-time distribution analysis (DDA) has been used to explore the plasma membrane fluidity of multidrug-resistant cancer cells (LR73 carcinoma cells) and also to characterize the influence of various membrane agents present in the extracellular medium. DDA is a recent single-molecule technique, based on fluorescence correlation spectroscopy (FCS), well suited to retrieve local organization of cell membrane. The method was conducted on a large number of living cells, which enabled us to get a detailed overview of plasma membrane microviscosity, and plasma membrane micro-organization, between the cells of the same line. Thus, we clearly reveal the higher heterogeneity of plasma membrane in multidrug-resistant cancer cells in comparison with the nonresistant ones (denoted sensitive cells). We also display distinct modifications related to a membrane fluidity modulator, benzyl alcohol, and two revertants of multidrug resistance, verapamil and cyclosporin-A. A relation between the distribution of the diffusion-time values and the modification of membrane lateral heterogeneities is proposed.

  3. Reversal of ABC drug transporter-mediated multidrug resistance in cancer cells: Evaluation of current strategies

    PubMed Central

    Wu, Chung-Pu; Calcagno, Anna Maria; Ambudkar, Suresh V.

    2008-01-01

    Overexpression of ATP-binding cassette (ABC) drug transporters that actively efflux a variety of amphipathic compounds can cause multidrug resistance (MDR) in cancer cells, which is a major obstacle in the success of cancer chemotherapy. The development of synthetic small molecule compounds or the identification of natural products that block ABC transporter-mediated efflux has been the conventional approach used to combat MDR. The strategy of using chemosensitizers, however, has not been successful in clinical cancer chemotherapy. Therefore, alternative approaches to identify or to synthesize compounds that can induce selective toxicity in cancer cells overexpressing one or more ABC transporters have been undertaken. This review summarizes the recent advances in identifying strategies to restore sensitivity to chemotherapeutics in multidrug resistant cancer cells. PMID:19079736

  4. Inorganic nanoparticle-based drug codelivery nanosystems to overcome the multidrug resistance of cancer cells.

    PubMed

    Chen, Yu; Chen, Hangrong; Shi, Jianlin

    2014-08-04

    Biocompatible inorganic material-based nanosystems provide a novel choice to effectively circumvent the intrinsic drawbacks of traditional organic materials in biomedical applications, especially in overcoming the multidrug resistance (MDR) of cancer cells due to their unique structural and compositional characteristics, for example, high stability, large surface area, tunable compositions, abundant physicochemical multifunctionalities, and specific biological behaviors. In this review, we focus on the recent developments in the construction of inorganic nanoparticles-based drug codelivery nanosystems (mesoporous SiO2, Fe3O4, Au, Ag, quantum dots, carbon nanotubes, graphene oxide, LDH, etc.) to efficiently circumvent the MDR of cancer cells, including the well-known codelivery of small molecular anticancer drug/macromolecular therapeutic gene and codelivery of small molecular chemosensitizer/anticancer drug, and very recently explored codelivery of targeting ligands/anticancer drug, codelivery of energy/anticancer drug, and codelivery of contrast agent for diagnostic imaging and anticancer drug. The unsolved issues, future developments, and potential clinical translations of these codelivery nanosystems are also discussed. These elaborately designed biocompatible inorganic materials-based nanosystems offer an unprecedented opportunity and show the encouraging bright future for overcoming the MDR of tumors in clinic personalized medicine and the pharmaceutical industry.

  5. Induction of apoptotic cell death by betulin in multidrug-resistant human renal carcinoma cells.

    PubMed

    Yim, Nam-Hui; Jung, Young Pil; Kim, Aeyung; Kim, Taesoo; Ma, Jin Yeul

    2015-08-01

    Betulin, a triterpene from the bark of various species of birch tree, has various biological effects, including antiviral, antifungal and anticancer activities. The aim of the present study was to elucidate the mechanisms underlying the apoptotic effect of betulin in RCC4 multidrug-resistant human renal carcinoma cells. To evaluate anticancer activity, we performed cell viability and caspase activity assays, a proteome profiler array and western blot analysis in RCC4 cells. Betulin significantly decreased RCC4 cell viability in a time- and concentration-dependent manner. Betulin activated caspase family proteins, including caspase-3, -7, -8 and -9, and increased the expression of apoptosis-related proteins, including PARP and Bcl-2 family members. In an apoptosis array, betulin activated the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors TRAIL R1/DR4 and R2/DR5, and tumour necrosis factor receptor 1 (TNFR1), suggesting that betulin treatment leads to induction of apoptosis through both intrinsic and extrinsic apoptosis pathways in RCC4 cells. Notably, betulin significantly enhanced cytotoxicity and PARP cleavage in etoposide-treated RCC4 cells, and downregulated the expression of multidrug resistance protein 1 (MDR1). Taken together, our findings suggest that the anticancer effects of betulin involve induction of apoptosis and sensitisation of RCC4 cells, providing potentially useful information applicable to the use of betulin in renal cancer treatment.

  6. Elevated expression of Nrf2 mediates multidrug resistance in CD133+ head and neck squamous cell carcinoma stem cells

    PubMed Central

    Lu, Bao-Cai; Li, Jing; Yu, Wen-Fa; Zhang, Guo-Zheng; Wang, Hui-Min; Ma, Hui-Min

    2016-01-01

    Enhanced expression of the ATP-binding cassette (ABC) transporter protein ABC sub-family G member 2 (ABCG2) in cancer stem cells (CSCs) plays a major role in chemotherapeutic drug efflux, which results in therapy failure and tumor relapse. In addition to downregulating apoptosis in CSCs, it has been reported that the transcriptional upregulation of the redox sensing factor Nrf2 is involved in the upregulation of ABCG2 expression and consequent chemoresistance. The current study investigated the presence of cancer stem-like side population (SP) cells from head and neck squamous cell carcinoma (HNSCC) samples, and evaluated the Nrf2 expression profile and multidrug resistance properties of HNSCC stem cells. Fluorescence-activated cell sorting was used for SP cells detection, while reverse transcription-polymerase chain reaction was used for the analysis of Nrf2 expression. The present study identified ~2.1% SP cells present in HNSCC specimens, which were positive for cluster of differentiation (CD)133 expression and displayed significantly elevated messenger RNA expression of Nrf2, compared with non-SP cells. These data suggest that the ABC transporter ABCG2 is highly upregulated in SP cells, and this results in multidrug resistance. In addition, these CD133+ cells underwent rapid proliferation and exhibited high self-renewal and tumorigenic properties. Taken together, the present findings suggest that elevated expression of Nrf2 mediated drug resistance in HNSCC CSCs, which may be one of the causative factors for cancer treatment failure. Therefore, novel anti-cancer drugs that downregulate the Nrf2 signaling pathway could effectively improve the treatment and survival rate of patients with HNSCC. PMID:28101198

  7. [The role of cell wall organization and active efflux pump systems in multidrug resistance of bacteria].

    PubMed

    Hasdemir, Ufuk

    2007-04-01

    Multiple antibiotic resistance of clinically important bacteria are of major concern worldwide. Alterations of drug targets or enzymatic inactivation of antimicrobial agents are the well known mechanisms of antimicrobial drug resistance. Besides these well known mechanisms, recent studies have shown that a further resistance mechanism, active drug efflux, has become increasingly important in the current threat of multidrug resistance. It involves certain bacterial transport proteins which pump out toxic antimicrobial compounds from the cell. Drug efflux pump proteins in bacteria fall into five distinct protein super families [ATP binding cassette super family (ABC), Major facilitator super family (MFS), Small multidrug resistance super family (SMR), Multidrug and toxic compound extrusion (MATE) super family, Resistance-nodulation-cell division (RND) super family] and are mostly encoded by chromosomal genes. Among them, the members of RND protein super family are widely distrubuted in Gram negative bacteria and play siginificant role in both, intrinsic and acquired multidrug resistance of these bacteria with very wide substrate specificity. RND type multidrug efflux proteins usually function together with an outer membrane canal protein (OMP) and a membrane fusion protein (MFP) to pump out drugs. AcrAB-TolC of Escherichia coli and MexAB-OprM of Pseudomonas aeruginosa are the typical examples of these tripartite systems. They are constitutively expressed in wild type cells and play significant role in intrinsic resistance of these bacteria. However, multidrug resistance which is of major clinical significance, rises as a result of overexpression of these pump systems due to mutations and elevated levels of resistance are recorded to structurally unrelated antimicrobial drugs such as fluoroquinolones, beta-lactams, tetracyclines, chloramphenicol, trimethoprim, aminoglycosides and toxic compunds. Synthesis of RND type pump proteins are regulated by complex genetic

  8. Targeting ABCB1-mediated tumor multidrug resistance by CRISPR/Cas9-based genome editing

    PubMed Central

    Yang, Yang; Qiu, Jian-Ge; Li, Yong; Di, Jin-Ming; Zhang, Wen-Ji; Jiang, Qi-Wei; Zheng, Di-Wei; Chen, Yao; Wei, Meng-Ning; Huang, Jia-Rong; Wang, Kun; Shi, Zhi

    2016-01-01

    The RNA-guided clustered regularly interspaced short palindromic (CRISPR) in combination with a CRISPR-associated nuclease 9 (Cas9) nuclease system is a new rapid and precise technology for genome editing. In the present study, we applied the CRISPR/Cas9 system to target ABCB1 (also named MDR1) gene which encodes a 170 kDa transmembrane glycoprotein (P-glycoprotein/P-gp) transporting multiple types of chemotherapeutic drugs including taxanes, epipodophyllotoxins, vinca alkaloids and anthracyclines out of cells to contribute multidrug resistance (MDR) in cancer cells. Our data showed that knockout of ABCB1 by CRISPR/Cas9 system was succesfully archieved with two target sgRNAs in two MDR cancer cells due to the alteration of genome sequences. Knockout of ABCB1 by CRISPR/Cas9 system significantly enhances the sensitivity of ABCB1 substrate chemotherapeutic agents and the intracellular accumulation of rhodamine 123 and doxorubicin in MDR cancer cells. Although now there are lots of limitations to the application of CRISPR/Cas9 for editing cancer genes in human patients, our study provides valuable clues for the use of the CRISPR/Cas9 technology in the investigation and conquest of cancer MDR. PMID:27725879

  9. Phytochemical analysis and cytotoxicity towards multidrug-resistant leukemia cells of essential oils derived from Lebanese medicinal plants.

    PubMed

    Saab, Antoine M; Guerrini, Alessandra; Sacchetti, Gianni; Maietti, Silvia; Zeino, Maʼen; Arend, Joachim; Gambari, Roberto; Bernardi, Francesco; Efferth, Thomas

    2012-12-01

    Juniperus excelsa fruit essential oil as well as J. oxycedrus, Cedrus libani, and Pinus pinea wood essential oils have been obtained with yields between 2.2 ± 0.3 % to 3.4 ± 0.5 % and analyzed by gas chromatography. Sesquiterpenes mainly characterized C. libani and J. oxycedrus essential oils, while in P. pinea and J. excelsa, monoterpenes were the most abundant compounds. In J. oxycedrus, cis-calamenene (7.8 %), cuparene (3.8 %), and cis-thujopsenal (2.0 %) have been detected for the first time. The cytotoxic activity of these essential oils against drug-sensitive CCRF-CEM and multidrug-resistant P-glycoprotein-expressing CEM/ADR5000 leukemia cells has been investigated (IC₅₀ values: 29.46 to 61.54 µg/mL). Remarkably, multidrug-resistant CEM/ADR5000 cells did not reveal cross-resistance, indicating that these essential oils might be useful to treat otherwise drug-resistant and refractory tumors.

  10. Preliminary studies on phenothiazine-mediated reversal of multidrug resistance in mouse lymphoma and COLO 320 cells.

    PubMed

    Pajak, Beata; Molnar, Joseph; Engi, Helga; Orzechowski, Arkadiusz

    2005-01-01

    The ability of phenothiazine derivatives to inhibit the transport activity of P-glycoprotein in resistant mouse lymphoma and MDR/COLO 320 cells was studied. A rhodamine 123 efflux from the above-mentioned neoplastic cells in the presence of tested compounds was examined by flow cytometry. Two of the phenothiazine derivatives, namely perphenazine and prochlorperazine dimaleate, proved to be effective inhibitors of the rhodamine efflux. Other tested phenothiazine derivatives (promethazine hydrochloride, oxomemazine, methotrimeprazine maleate, trifluoropromazine hydrochloride, trimeprazine) also modulated the intracellular drug accumulation in both resistant cell lines, however, they exerted additional cytotoxic effects. The differences observed between the effects of the test compounds on intracellular drug accumulation could be the outcome of differences in phenothiazine's chemical structure, which is crucial for drug-cell membrane interactions. The results of this study provide information about a new group of compounds that offer promise in multidrug resistance reversal in tumor cells.

  11. Salvianolic acid B reverses multidrug resistance in HCT‑8/VCR human colorectal cancer cells by increasing ROS levels.

    PubMed

    Guo, Piaoting; Wang, Songpo; Liang, Wei; Wang, Wenjing; Wang, Huijun; Zhao, Miaomiao; Liu, Xiaowei

    2017-02-01

    Salvianolic acid B (SalB) a water‑soluble phenolic compound, extracted from Salvia miltiorrhiza, has previously been demonstrated to reverse tumor multidrug resistance (MDR), including in colorectal cancer. Reactive oxygen species (ROS) are oxygen radicals generated during aerobic metabolism (superoxide and hydroxyl radicals) and superoxide easily generating free radicals (H2O2). The concept that increased ROS levels can lead to augmented tumor cell‑sensitivity to chemotherapy drugs has become notable. The aim of the present study was to elucidate the role of ROS in mediating the effect of SalB on drug resistance and the correlation with drug resistance‑associated protein, P‑glycoprotein (P‑gp), and apoptosis‑associated proteins, B‑cell lymphoma 2 (Bcl‑2) and Bcl‑2‑associated X (Bax). In the current study, through utilizing the multidrug resistant colorectal cancer cell line, HCT‑8/VCR, it was demonstrate that SalB reversed MDR in HCT‑8/VCR. In addition, SalB significantly increased ROS levels, which may have accelerated the apoptosis of HCT‑8/VCR cells by downregulating Bcl‑2 and increasing Bax protein expression. Furthermore the increased intracellular ROS levels may have inhibited P‑gp expression at the gene and protein levels. In conclusion, the data of the current study demonstrate that SalB reversed MDR in HCT‑8/VCR cells, and the effect is associated with increased ROS levels, which may downregulate P‑gp expression and promote tumor cell apoptosis, which in turn increases the sensitivity of drug‑resistant cells to chemotherapy drugs.

  12. Polysaccharide-lecithin reverse micelles with enzyme-degradable triglyceride shell for overcoming tumor multidrug resistance.

    PubMed

    Su, Chia-Wei; Chen, San-Yuan; Liu, Dean-Mo

    2013-05-08

    A newly-designed drug carrier with enzyme-triggered release behavior and the ability to circumvent multidrug resistance was successfully developed. By optimizing the ratio of lecithin and polysaccharide in reverse micelles, encapsulation efficiency and encapsulation stability can be significantly improved.

  13. Multivalent Aptamer-RNA Conjugates for Simple and Efficient Delivery of Doxorubicin/siRNA into Multidrug-Resistant Cells.

    PubMed

    Jeong, Hyosook; Lee, Soo Hyeon; Hwang, Yeonju; Yoo, Hyundong; Jung, Heesun; Kim, Sun Hwa; Mok, Hyejung

    2017-04-01

    Multivalent aptamer-siRNA conjugates containing multiple mucin-1 aptamers and BCL2-specific siRNA are synthesized, and doxorubicin, an anthracycline anticancer drug, is loaded into these conjugates through intercalation with nucleic acids. These doxorubicin-incorporated multivalent aptamer-siRNA conjugates are transfected to mucin-1 overexpressing MCF-7 breast cancer cells and their multidrug-resistant cell lines. Doxorubicin-incorporated multivalent aptamer-siRNA conjugates exert promising anticancer effects, such as activation of caspase-3/7 and decrease of cell viability, on multidrug-resistant cancer cells because of their high intracellular uptake efficiency. Thus, this delivery system is an efficient tool for combination oncotherapy with chemotherapeutics and nucleic acid drugs to overcome multidrug resistance.

  14. Ceramide glycosylation potentiates cellular multidrug resistance.

    PubMed

    Liu, Y Y; Han, T Y; Giuliano, A E; Cabot, M C

    2001-03-01

    Ceramide glycosylation, through glucosylceramide synthase (GCS), allows cellular escape from ceramide-induced programmed cell death. This glycosylation event confers cancer cell resistance to cytotoxic anticancer agents [Liu, Y. Y., Han, T. Y., Giuliano, A. E., and M. C. Cabot. (1999) J. Biol. Chem. 274, 1140-1146]. We previously found that glucosylceramide, the glycosylated form of ceramide, accumulates in adriamycin-resistant breast carcinoma cells, in vinblastine-resistant epithelioid carcinoma cells, and in tumor specimens from patients showing poor response to chemotherapy. Here we show that multidrug resistance can be increased over baseline and then totally reversed in human breast cancer cells by GCS gene targeting. In adriamycin-resistant MCF-7-AdrR cells, transfection of GCS upgraded multidrug resistance, whereas transfection of GCS antisense markedly restored cellular sensitivity to anthracyclines, Vinca alkaloids, taxanes, and other anticancer drugs. Sensitivity to the various drugs by GCS antisense transfection increased 7- to 240-fold and was consistent with the resumption of ceramide-caspase-apoptotic signaling. GCS targeting had little influence on cellular sensitivity to either 5-FU or cisplatin, nor did it modify P-glycoprotein expression or rhodamine-123 efflux. GCS antisense transfection did enhance rhodamine-123 uptake compared with parent MCF-7-AdrR cells. This study reveals that GCS is a novel mechanism of multidrug resistance and positions GCS antisense as an innovative force to overcome multidrug resistance in cancer chemotherapy.

  15. Doxorubicin and siRNA Codelivery via Chitosan-Coated pH-Responsive Mixed Micellar Polyplexes for Enhanced Cancer Therapy in Multidrug-Resistant Tumors.

    PubMed

    Butt, Adeel Masood; Amin, Mohd Cairul Iqbal Mohd; Katas, Haliza; Abdul Murad, Nor Azian; Jamal, Rahman; Kesharwani, Prashant

    2016-12-05

    This study investigated the potential of chitosan-coated mixed micellar nanocarriers (polyplexes) for codelivery of siRNA and doxorubicin (DOX). DOX-loaded mixed micelles (serving as cores) were prepared by thin film hydration method and coated with chitosan (CS, serving as outer shell), and complexed with multidrug resistance (MDR) inhibiting siRNA. Selective targeting was achieved by folic acid conjugation. The polyplexes showed pH-responsive enhanced DOX release in acidic tumor pH, resulting in higher intracellular accumulation, which was further augmented by downregulation of mdr-1 gene after treatment with siRNA-complexed polyplexes. In vitro cytotoxicity assay demonstrated an enhanced cytotoxicity in native 4T1 and multidrug-resistant 4T1-mdr cell lines, compared to free DOX. Furthermore, in vivo, polyplexes codelivery resulted in highest DOX accumulation and significantly reduced the tumor volume in mice with 4T1 and 4T1-mdr tumors as compared to the free DOX groups, leading to improved survival times in mice. In conclusion, codelivery of siRNA and DOX via polyplexes has excellent potential as targeted drug nanocarriers for treatment of MDR cancers.

  16. Tolerance to drug-induced cell death favours the acquisition of multidrug resistance in Leishmania

    PubMed Central

    Moreira, W; Leprohon, P; Ouellette, M

    2011-01-01

    The control of the protozoan parasite Leishmania relies on few drugs with unknown cellular targets and unclear mode of action. Several antileishmanials, however, were shown to induce apoptosis in Leishmania and this death mechanism was further studied in drug-sensitive and drug-resistant Leishmania infantum. In sensitive parasites, antimonials (SbIII), miltefosine (MF) and amphotericin B (AMB), but not paromomycin (PARO), triggered apoptotic cell death associated with reactive oxygen species (ROS). In contrast, Leishmania mutants resistant to SbIII, MF or AMB not only failed to undergo apoptosis following exposure to their respective drugs, but also were more tolerant towards apoptosis induced by other antileishmanials, provided that these killed Leishmania via ROS production. Such tolerance favored the rapid acquisition of multidrug resistance. PARO killed Leishmania in a non-apoptotic manner and failed to produce ROS. PARO resistance neither protected against drug-induced apoptosis nor provided an increased rate of acquisition of resistance to other antileishmanials. However, the PARO-resistant mutant, but not SbIII-, MF- or AMB-resistant mutants, became rapidly cross-resistant to methotrexate, a model drug also not producing ROS. Our results therefore link the mode of killing of drugs to tolerance to cell death and to a facilitated emergence of multidrug resistance. These findings may have fundamental implications in the field of chemotherapeutic interventions. PMID:21881603

  17. In silico identified targeted inhibitors of P-glycoprotein overcome multidrug resistance in human cancer cells in culture

    PubMed Central

    Follit, Courtney A; Brewer, Frances K; Wise, John G; Vogel, Pia D

    2015-01-01

    Failure of cancer chemotherapies is often linked to the over expression of ABC efflux transporters like the multidrug resistance P-glycoprotein (P-gp). P-gp expression in cells leads to the elimination of a variety of chemically unrelated, mostly cytotoxic compounds. Administration of chemotherapeutics during therapy frequently selects for cells that over express P-gp and are therefore capable of robustly exporting diverse compounds, including chemotherapeutics, from the cells. P-gp thus confers multidrug resistance to a majority of drugs currently available for the treatment of cancers and diseases like HIV/AIDS. The search for P-gp inhibitors for use as co-therapeutics to combat multidrug resistances has had little success to date. In a previous study (Brewer et al., Mol Pharmacol 86: 716–726, 2014), we described how ultrahigh throughput computational searches led to the identification of four drug-like molecules that specifically interfere with the energy harvesting steps of substrate transport and inhibit P-gp catalyzed ATP hydrolysis in vitro. In the present study, we demonstrate that three of these compounds reversed P-gp-mediated multidrug resistance of cultured prostate cancer cells to restore sensitivity comparable to naïve prostate cancer cells to the chemotherapeutic drug, paclitaxel. Potentiation concentrations of the inhibitors were <3 μmol/L. The inhibitors did not exhibit significant toxicity to noncancerous cells at concentrations where they reversed multidrug resistance in cancerous cells. Our results indicate that these compounds with novel mechanisms of P-gp inhibition are excellent leads for the development of co-therapeutics for the treatment of multidrug resistances. PMID:26516582

  18. MiR-30a Decreases Multidrug Resistance (MDR) of Gastric Cancer Cells

    PubMed Central

    Li, Chunying; Zou, Jinhai; Zheng, Guoqi; Chu, Jiankun

    2016-01-01

    Background The effectiveness of chemotherapy for gastric cancer is largely limited by either intrinsic or acquired drug resistance. In this study, we aimed to explore the association between miR-30a dysregulation and multidrug resistance (MDR) in gastric cancer cells. Material/Methods We recruited 20 patients with advanced gastric cancer. Chemosensitivity was assessed after completion of the chemotherapy. SGC-7901 and SGC-7901/DDP cells were transfected for miR-30a overexpression or knockdown. Then, MTT assay was performed to assess the IC50 of DPP and 5-FU in SGC-7901 and SGC-7901/DDP cells. Flow cytometry analysis was used to detect DPP- and 5-FU-induced cell apoptosis. Western blot analysis and immunofluorescence staining were used to assess EMT of the cells. Results MiR-30a was significantly downregulated in the chemoresistant tissues. In both SGC-7901 and SGC-7901/DDP cells, miR-30a overexpression decreased the expression of P-gp, a MDR-related protein. MTT assay and flow cytometry analysis showed that miR-30a inhibition increased chemoresistance, while miR-30a overexpression decreased chemoresistance in gastric cancer cells. Both Western blot analysis and immunofluorescence staining confirmed that miR-30a inhibition decreased E-cadherin but increased N-cadherin in SGC-7901 cells, while miR-30a overexpression increased E-cadherin but decreased N-cadherin in SGC-7901 cells. Conclusions MiR-30a can decrease multidrug resistance (MDR) of gastric cancer cells. It is also an important miRNA modulating EMT of the cancer cells.

  19. Circumvention of multi-drug resistance of cancer cells by Chinese herbal medicines

    PubMed Central

    2010-01-01

    Multi-drug resistance (MDR) of cancer cells severely limits therapeutic outcomes. A proposed mechanism for MDR involves the efflux of anti-cancer drugs from cancer cells, primarily mediated by ATP-binding cassette (ABC) membrane transporters including P-glycoprotein. This article reviews the recent progress of using active ingredients, extracts and formulae from Chinese medicine (CM) in circumventing ABC transporters-mediated MDR. Among the ABC transporters, Pgp is the most extensively studied for its role in MDR reversal effects. While other MDR reversal mechanisms remain unclear, Pgp inhibition is a criterion for further mechanistic study. More mechanistic studies are needed to fully establish the pharmacological effects of potential MDR reversing agents. PMID:20653978

  20. Modulation of multidrug resistance gene expression in human breast cancer cells by (-)-gossypol-enriched cottonseed oil.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    P-glycoprotein, the product of the multidrug resistance 1 gene, acts as an efflux pump and prevents sufficient intracellular accumulation of several anticancer agents. Thus, it plays a major role in multidrug cancer resistance. Using the non-radioactive cell proliferation MTS assay, none of three ...

  1. Biofunctionalized polymer-lipid supported mesoporous silica nanoparticles for release of chemotherapeutics in multidrug resistant cancer cells.

    PubMed

    Zhang, Xinxin; Li, Feifei; Guo, Shiyan; Chen, Xi; Wang, Xiaoli; Li, Juan; Gan, Yong

    2014-04-01

    Multidrug resistance (MDR) is a major impediment to the success of cancer chemotherapy. A polymer-lipid supported mesoporous silica nanoparticle (PLS-MSNs) is described here to facilitate intracellular delivery of anticancer drug and enhance the antitumor efficacy against MDR breast cancer cells. By coating MSNs with a synthetic dual-functional polymer-lipid material P123-DOPE, the supported membrane acted as an intact barrier against the escape of encapsulated drugs before reaching the target cells, leading to depolymerization and triggered storm release of loaded irinotecan (CPT-11) in acidic endosomal pH of tumor cells. In addition, P123-DOPE can inhibit breast cancer resistance protein (BCPR) mediated CPT-11 efflux in drug resistant MCF-7/BCRP breast cancer cells, thus acting as a "door blocker". Compared to free CPT-11, PLS-MSNs resulted in a maximum increase in the intracellular CPT-11 concentration (12.9-fold), had 7.1-fold higher cytotoxicity and processed a stronger cell cycle arrest in MCF-7/BCRP cells. Moreover, CPT-11 loaded PLS-MSNs showed high therapeutic performance and low toxicity in BALB/c nude mice bearing drug resistant breast tumors, with an inhibition rate of 81.2% compared to free CPT-11 treatment group. The reported PLS-MSNs provide promising applicability in future preclinical and clinical MDR cancer treatment.

  2. Multidrug resistance protein 1 (ABCC1) confers resistance to arsenic compounds in human myeloid leukemic HL-60 cells.

    PubMed

    Xu, Shi; Zhang, Yan Fang; Carew, Micheal W; Hao, Wen Hui; Loo, Jacky Fong Chuen; Naranmandura, Hua; Le, X Chris

    2013-06-01

    Arsenic trioxide (As(2)O(3)) is established as one of the most effective drugs for treatment of patients with acute promyelocytic leukemia, as well as other types of malignant tumors. However, HL-60 cells are resistant to As(2)O(3), and little is known about the underlying resistance mechanism for As(2)O(3) and its biomethylation products, namely, monomethylarsonous acid (MMA(III)) on the treatment of tumors. In the present study, we investigated the molecular mechanisms underlying iAs(III) and its intermediate metabolite MMA(III)-induced anticancer effects in the HL-60 cells. Here, we show that the HL-60 cells exhibit resistance to inorganic iAs(III) (IC(50) = 10 μM), but are relatively sensitive to its intermediate MMA(III) (IC(50) = 3.5 μM). Moreover, we found that the multidrug resistance protein 1 (MRP1), but not MRP2, is expressed in HL-60 cells, which reduced the intracellular arsenic accumulation, and conferred resistance to inorganic iAs(III) and MMA(III). Pretreatment of HL-60 with MK571, an inhibitor of MRP1, significantly increased iAs(III) and MMA(III)-induced cytotoxicity and arsenic accumulations, suggesting that the expression of MRP1/4 may lead to HL-60 cells resistance to trivalent arsenic compounds.

  3. The plant alkaloid voacamine induces apoptosis-independent autophagic cell death on both sensitive and multidrug resistant human osteosarcoma cells.

    PubMed

    Meschini, Stefania; Condello, Maria; Calcabrini, Annarica; Marra, Manuela; Formisano, Giuseppe; Lista, Pasquale; De Milito, Angelo; Federici, Elena; Arancia, Giuseppe

    2008-11-01

    In our previous studies, the bisindolic alkaloid voacamine (VOA), isolated from the plant Peschiera fuchsiaefolia, proved to exert a chemosensitizing effect on cultured multidrug resistant (MDR) osteosarcoma cells exposed to doxorubicin (DOX). In particular, VOA was capable of inhibiting P-glycoprotein action in a competitive way, thus explaining the enhancement of the cytotoxic effect induced by DOX on MDR cells. Afterwards, preliminary observations suggested that such an enhancement did not involve the apoptotic process but was due instead to the induction of autophagic cell death. The results of the present investigation demonstrate that the plant alkaloid VOA is an autophagy inducer able to exert apoptosis-independent cytotoxic effect on both wild-type and MDR tumor cells. In fact, under treatment condition causing about 50 percent of cell death, no evidence of apoptosis could be revealed by microscopical observations, Annexin V-FITC labeling and analysis of PARP cleavage, whereas the same cells underwent apoptosis when treated with apoptosis inducers, such as doxorubicin and staurosporine. Conversely, VOA-induced autophagy was clearly evidentiated by electron microscopy observations, monodansylcadaverine staining, LC3 expression, and conversion. These results were confirmed by the analysis of the modulating effects of the pretreatment with autophagy inhibitors prior to VOA administration. In addition, transfection of osteosarcoma cells with siRNA against ATG genes reduced VOA cytotoxicity. In conclusion, considering the very debated dual role of autophagy in cancer cells (protective or lethal, pro- or anti- apoptotic) our findings seem to demonstrate, at least in vitro, that a natural product able to induce autophagy can be effective against drug resistant tumors, either used alone or in association with conventional chemotherapeutics.

  4. The multidrug-resistance transporter Abcc3 protects NK cells from chemotherapy in a murine model of malignant glioma

    PubMed Central

    Pessina, Sara; Cantini, Gabriele; Kapetis, Dimos; Cazzato, Emanuela; Di Ianni, Natalia; Finocchiaro, Gaetano; Pellegatta, Serena

    2016-01-01

    ABSTRACT Abcc3, a member of the ATP-binding cassette transporter superfamily, plays a role in multidrug resistance. Here, we found that Abcc3 is highly expressed in blood-derived NK cells but not in CD8+ T cells. In GL261 glioma-bearing mice treated with the alkylating agent temozolomide (TMZ) for 5 d, an early increased frequency of NK cells was observed. We also found that Abcc3 is strongly upregulated and functionally active in NK cells from mice treated with TMZ compared to controls. We demonstrate that Abcc3 is critical for NK cell survival during TMZ administration; more importantly, Akt, involved in lymphocyte survival, is phosphorylated only in NK cells expressing Abcc3. The resistance of NK cells to chemotherapy was accompanied by increased migration and homing in the brain at early time points. Cytotoxicity, evaluated by IFNγ production and specific lytic activity against GL261 cells, increased peripherally in the later phases, after conclusion of TMZ treatment. Intra-tumor increase of the NK effector subset as well as in IFNγ, granzymes and perforin-1 expression, were found early and persisted over time, correlating with a profound modulation on glioma microenvironment induced by TMZ. Our findings reveal an important involvement of Abcc3 in NK cell resistance to chemotherapy and have important clinical implications for patients treated with chemo-immunotherapy. PMID:27467914

  5. Salvianolic acid A shows selective cytotoxicity against multidrug-resistant MCF-7 breast cancer cells.

    PubMed

    Wang, Xin; Wang, Chunyan; Zhang, Longjiang; Li, Yanjun; Wang, Shouju; Wang, Jiandong; Yuan, Caiyun; Niu, Jia; Wang, Chengsheng; Lu, Guangming

    2015-02-01

    Multidrug resistance (MDR) is a major cause for incurable breast cancer. Salvianolic acid A (SAA), the hydrophilic polyphenolic derivative of Salvia miltiorrhiza Bunge (Danshen/Red Sage), was examined for cytotoxicities to MDR MCF-7 human breast cancer cells and their parental counterparts. We have shown that SAA inhibited proliferation, caused cell cycle arrest at the S phase, and induced apoptosis dose dependently to the two kinds of cancer cells. However, the resistant cells were significantly susceptible to the inhibition of SAA compared with the parental cells. SAA increased the level of reactive oxygen species (ROS) by 6.2-fold in the resistant cells, whereas the level of SAA-induced ROS changed only by 1.6-fold in their parental counterparts. Thus, the data showed that the selective cytotoxicity resulted from the hypersensitivity of the resistant cells to the strongly elevated ROS by SAA. In addition, SAA-triggered apoptosis was associated with increased caspase-3 activity, disrupted mitochondrial membrane potential, downregulated Bcl-2 expression, and upregulated Bax expression in the resistant cells. Moreover, SAA downregulated the level of P-glycoprotein, which was overexpressed in the resistant cells. This indicated that SAA modulated MDR. Furthermore, SAA showed higher antitumor activity than did doxorubicin in xenografts established from the resistant cells. The present work raised a possibility that SAA might be considered a potential choice to overcome MDR for the selective susceptibility of the resistant breast cancer cells to SAA treatment.

  6. Sensitization of Cells Overexpressing Multidrug Resistant Proteins by Pluronic P85

    PubMed Central

    Batrakova, Elena V.; Li, Shu; Alakhov, Valery Yu.; Elmquist, William F.; Miller, Donald W.; Kabanov, Alexander V.

    2011-01-01

    Purpose This study evaluated the chemosensitizing effects of Pluronic P85 (P85) on the cells expressing multidrug resistance-associated proteins, MRP1 and MRP2. Methods Cell models included MRP1- and MRP2-transfected MDCKII cells, as well as doxorubicin-selected COR-L23/R cells overexpressing MRP1. Effects of P85 on cellular accumulation and cytotoxicity of vinblastine and doxorubicin were determined. Mechanistic studies characterized the effects of P85 on ATP and reduced glutathione (GSH) intracellular levels as well as MRPs ATPase and glutathione-S-transferase (GST) activities in these cells. Results Considerable increases of vinblastine and doxorubicin accumulation in the cells overexpressing MRP1 and MRP2 in the presence of P85 were observed, while no statistically significant changes in the drug accumulation in the parental cells were found. P85 treatment caused an inhibition of MRPs ATPase activity. Furthermore, P85 induced ATP depletion in these cells similar to that previously reported for Pgp-overexpressing cells. In addition, reduction of GSH intracellular levels and decrease of GST activity following P85 treatment were observed. Finally, significant enhancement of cytotoxicity of vinblastine and doxorubicin by P85 in MRPs -overexpressing cells was demonstrated. Conclusions This study suggests that P85 can sensitize cells overexpressing MRP1 and MRP2, which could be useful for chemotherapy of cancers that display these resistant mechanisms. PMID:14620511

  7. Synergistic effect of a novel cyclic pentadepsipeptide, neoN-methylsansalvamide, and paclitaxel on human multidrug resistance cancer cell lines.

    PubMed

    Lee, Hee-Seok; Phat, Chanvorleak; Choi, Sang-Un; Lee, Chan

    2013-06-01

    NeoN-methylsansalvamide is a novel low-molecular-weight cyclic pentadepsipeptide that exerts cytotoxic effects on various human cancer cell lines. Its structural analysis using liquid chromatography mass/mass spectrometry showed the cyclic structure sequence -phenylalanine-leucine-valine-N-methylleucine-leucic acid-. The intrinsic cytotoxic and multidrug resistance reversal effects of neoN-methylsansalvamide were evaluated on the human cancer cell lines MES-SA and HCT15 as well as on their multidrug resistance sublines (MES-SA/DX5 and HCT15/CL05, respectively) using the sulforhodamine B assay. The EC50 values of paclitaxel for MES-SA, HCT15, and for the multidrug resistance sublines MES-SA/DX5 and HCT15/CL05 were 1.00±0.20, 0.85±0.63, 10.00±0.53, and >1000 nmol/l, respectively. However, the EC50 values for paclitaxel including 3 μmol/l neoN-methylsansalvamide for MES-SA/DX5, HCT15, and HCT15/CL02 were 1.58±0.12, 0.10±0.02, and 288.40±21.02 nmol/l, respectively. The in-vitro multidrug resistance reversal activity of neoN-methylsansalvamide was similar to that of the control verapamil. These finding suggests that a novel cyclic pentadepsipeptide, neoN-methylsansalvamide, is effective in reversing multidrug resistance in vitro, and this activity may be a major applicable biological function of this compound.

  8. (1)H nuclear magnetic resonance-based extracellular metabolomic analysis of multidrug resistant Tca8113 oral squamous carcinoma cells.

    PubMed

    Wang, Hui; Chen, Jiao; Feng, Yun; Zhou, Wenjie; Zhang, Jihua; Yu, Y U; Wang, Xiaoqian; Zhang, Ping

    2015-06-01

    A major obstacle of successful chemotherapy is the development of multidrug resistance (MDR) in the cancer cells, which is difficult to reverse. Metabolomic analysis, an emerging approach that has been increasingly applied in various fields, is able to reflect the unique chemical fingerprints of specific cellular processes in an organism. The assessment of such metabolite changes can be used to identify novel therapeutic biomarkers. In the present study, (1)H nuclear magnetic resonance (NMR) spectroscopy was used to analyze the extracellular metabolomic spectrum of the Tca8113 oral squamous carcinoma cell line, in which MDR was induced using the carboplatin (CBP) and pingyangmycin (PYM) chemotherapy drugs in vitro. The data were analyzed using the principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) methods. The results demonstrated that the extracellular metabolomic spectrum of metabolites such as glutamate, glycerophosphoethanol amine, α-Glucose and β-Glucose for the drug-induced Tca8113 cells was significantly different from the parental Tca8113 cell line. A number of biochemicals were also significantly different between the groups based on their NMR spectra, with drug-resistant cells presenting relatively higher levels of acetate and lower levels of lactate. In addition, a significantly higher peak was observed at δ 3.35 ppm in the spectrum of the PYM-induced Tca8113 cells. Therefore, (1)H NMR-based metabolomic analysis has a high potential for monitoring the formation of MDR during clinical tumor chemotherapy in the future.

  9. [Reversing effects of emodin on multidrug resistance in resistant HL-60/ADR cells].

    PubMed

    Chen, Ying-Yu; Li, Jing; Hu, Jian-Da; Zheng, Jing; Zheng, Zhi-Hong; Zhu, Liang-Fang; Chen, Xin-Ji; Lin, Zhen-Xing

    2013-12-01

    This study was aimed to investigate the reversing effects of emodin on multidrug resistance (MDR) in resistant HL-60/ADR cells, and to explore the underlying mechanisms. The MTT assay was used to assess the chemoresistance of HL-60/ADR cells to emodin and 8 chemotherapeutic agents commonly used in clinic. The reversal effects of emodin on MDR of HL-60/ADR cells were also evaluated by MTT method. DNA ploidy analysis and DNA Ladder assay were used to detect apoptosis-induced effects on HL-60/ADR cells via the adriamycin (ADR) and emodin combination. The expression changes of the drug resistance-associated genes and proteins were detected by RT-PCR and Western Blot respectively. The intracellular accumulation and subcellular distribution of ADR and DNR were measured by flow cytometry and confocal laser scanning microscopy. The results showed that emodin inhibited HL-60/ADR cell proliferation with an average IC50 value of 24.09 ± 1.72 µmol/L, which was similar to that of the parental HL-60 cells (average IC50 = 23.18 ± 0.87 µmol/L). HL-60/ADR cells were resistant to a variety of chemotherapeutic agents, such as ADR, DNR, VP16, VCR,Ara-C, HHT, MTZ and THP. The reversal multiple were between 1.58 and 4.12 after the treatment with low concentration of emodin combined with the above mentioned different agents. The combination of ADR with emodin showed the best reversal effects, and the typical hypodiploid peak (apoptotic peak) and DNA ladder could be detected after the co-treatment.In addition, emodin down-regulated the mRNA and protein expression levels of MRP1, TOPOIIβ, GST π and BCL-2. Furthermore, the addition of emodin enhanced ADR and DNR intracellular accumulation and subcellular distribution in HL-60/ADR cells in dose-dependent manner. It is concluded that the emodin shows reversing effects on the multidrug resistant HL-60/ADR cells, possibly via decreasing the expression levels of drug resistance-associated genes, increasing the intracellular accumulation of

  10. Multidrug Resistance Protein-4 Influences Aspirin Toxicity in Human Cell Line

    PubMed Central

    Massimi, Isabella; Ciuffetta, Ambra; Temperilli, Flavia; Ferrandino, Francesca; Zicari, Alessandra; Pulcinelli, Fabio M.; Felli, Maria Pia

    2015-01-01

    Overexpression of efflux transporters, in human cells, is a mechanism of resistance to drug and also to chemotherapy. We found that multidrug resistance protein-4 (MRP4) overexpression has a role in reducing aspirin action in patients after bypass surgery and, very recently, we found that aspirin enhances platelet MRP4 levels through peroxisome proliferator activated receptor-α (PPARα). In the present paper, we verified whether exposure of human embryonic kidney-293 cells (Hek-293) to aspirin modifies MRP4 gene expression and its correlation with drug elimination and cell toxicity. We first investigated the effect of high-dose aspirin in Hek-293 and we showed that aspirin is able to increase cell toxicity dose-dependently. Furthermore, aspirin effects, induced at low dose, already enhance MRP4 gene expression. Based on these findings, we compared cell viability in Hek-293, after high-dose aspirin treatment, in MRP4 overexpressing cells, either after aspirin pretreatment or in MRP4 transfected cells; in both cases, a decrease of selective aspirin cell growth inhibition was observed, in comparison with the control cultures. Altogether, these data suggest that exposing cells to low nontoxic aspirin dosages can induce gene expression alterations that may lead to the efflux transporter protein overexpression, thus increasing cellular detoxification of aspirin. PMID:26491233

  11. Altered MRP is associated with multidrug resistance and reduced drug accumulation in human SW-1573 cells.

    PubMed Central

    Eijdems, E. W.; Zaman, G. J.; de Haas, M.; Versantvoort, C. H.; Flens, M. J.; Scheper, R. J.; Kamst, E.; Borst, P.; Baas, F.

    1995-01-01

    We have analysed the contribution of several parameters, e.g. drug accumulation, MDR1 P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP) and topoisomerase (topo) II, to drug resistance in a large set of drug-resistant variants of the human non-small-cell lung cancer cell line SW-1573 derived by selection with low concentrations of doxorubicin or vincristine. Selection with either drug nearly always resulted in MDR clones. The resistance of these clones could be explained by reduced drug accumulation and was associated with a decrease rather than an increase in the low MDR1 mRNA level. To test whether a decrease in MDR1 mRNA indirectly affected resistance in these cells, we introduced a MDR1-specific hammerhead ribozyme into wild-type SW-1573 cells. Although this led to a substantial reduction in MDR1 mRNA, it did not result in resistance. In all resistant clones we found an altered form of the multidrug resistance-associated protein (MRP), migrating slightly slower during SDS-polyacrylamide gel electrophoresis than MRP in parental cells. This altered MRP was also present in non-P-gp MDR somatic cell hybrids of the SW-1573 cells, demonstrating a clear linkage with the MDR phenotype. Treatment of crude cellular membrane fractions with N-glycanase, endoglycosidase H or neuraminidase showed that the altered migration of MRP on SDS-PAGE is due to a post-translational modification. There was no detectable difference in sialic acid content. In most but not all doxorubicin-selected clones, this MDR phenotype was accompanied by a reduction in topo II alpha mRNA level. No reduction was found in the clones selected with vincristine. We conclude from these results that selection of the SW-1573 cell line for low levels of doxorubicin or vincristine resistance, predominantly results in MDR with reduced drug accumulation associated with the presence of an altered MRP protein. This mechanism can be accompanied by other resistance mechanisms, such as reduced topo

  12. Long-Term Alteration of Reactive Oxygen Species Led to Multidrug Resistance in MCF-7 Cells

    PubMed Central

    Cen, Juan; Zhang, Li; Liu, Fangfang

    2016-01-01

    Reactive oxygen species (ROS) play an important role in multidrug resistance (MDR). This study aimed to investigate the effects of long-term ROS alteration on MDR in MCF-7 cells and to explore its underlying mechanism. Our study showed both long-term treatments of H2O2 and glutathione (GSH) led to MDR with suppressed iROS levels in MCF-7 cells. Moreover, the MDR cells induced by 0.1 μM H2O2 treatment for 20 weeks (MCF-7/ROS cells) had a higher viability and proliferative ability than the control MCF-7 cells. MCF-7/ROS cells also showed higher activity or content of intracellular antioxidants like glutathione peroxidase (GPx), GSH, superoxide dismutase (SOD), and catalase (CAT). Importantly, MCF-7/ROS cells were characterized by overexpression of MDR-related protein 1 (MRP1) and P-glycoprotein (P-gp), as well as their regulators NF-E2-related factor 2 (Nrf2), hypoxia-inducible factor 1 (HIF-1α), and the activation of PI3K/Akt pathway in upstream. Moreover, several typical MDR mediators, including glutathione S-transferase-π (GST-π) and c-Myc and Protein Kinase Cα (PKCα), were also found to be upregulated in MCF-7/ROS cells. Collectively, our results suggest that ROS may be critical in the generation of MDR, which may provide new insights into understanding of mechanisms of MDR. PMID:28058088

  13. Regulation of MDR1 gene expression in multidrug-resistant cancer cells is independent from YB-1.

    PubMed

    Kaszubiak, Alexander; Kupstat, Annette; Müller, Ursula; Hausmann, Romy; Holm, Per Sonne; Lage, Hermann

    2007-05-25

    The MDR1 gene encoded transmembrane ABC-transporter MDR1/P-glycoprotein can mediate the phenotype of multidrug resistance (MDR), a major obstacle in the clinical management of cancer patients. It was hypothesized that YB-1 is a fundamental regulatory factor of the MDR1 gene in tumor cells and can therewith enhance drug resistance. To analyze the potential impact of YB-1 in MDR cancer cells, two specific anti-YB-1 small interfering RNAs (siRNAs) were designed for transient triggering the gene-silencing RNA interference (RNAi) pathway in the MDR cell lines EPG85-257RDB and EPP85-181RDB as well as in their drug-sensitive counterparts EPG85-257P and EPP85-181P. Since both siRNAs showed biological activity, for stable inhibition of YB-1 corresponding tetracycline-inducible short hairpin RNA (shRNA)-encoding expression vectors were designed. By treatment of the cancer cells with these constructs, the expression of the targeted YB-1 encoding mRNA and protein was completely inhibited following tetracycline exposure. These gene-silencing effects were not accompanied by modulation of the MDR1 expression or by reversal of the drug-resistant phenotype. In conclusion, the data demonstrate the utility of the analyzed RNAs as powerful laboratory tools and indicate that YB-1 is not involved in the regulation of the MDR1 gene or the development of the drug-resistant phenotype in MDR cancer cells.

  14. Expression and activity of multidrug resistance proteins in mature endothelial cells and their precursors: A challenging correlation

    PubMed Central

    Bielawska-Pohl, Aleksandra; Wojtowicz, Karolina; Jura, Roksana; Paprocka, Maria; Wojdat, Elżbieta; Kozłowska, Urszula; Klimczak, Aleksandra; Grillon, Catherine; Kieda, Claudine; Duś, Danuta

    2017-01-01

    Active cellular transporters of harmful agents—multidrug resistance (mdr) proteins—are present in tumor, stem and endothelial cells, among others. While mdr proteins are broadly studied in tumor cells, their role in non-tumor cells and the significance of their action not connected with removal of harmful xenobiotics is less extensively documented. Proper assessment of mdr proteins expression is difficult. Mdr mRNA presence is most often evaluated but that does not necessarily correlate with the protein level. The protein expression itself is difficult to determine; usually cells with mdr overexpression are studied, not cells under physiological conditions, in which a low expression level of mdr protein is often insufficient for detection in vitro. Various methods are used to identify mdr mRNA and protein expression, together with functional tests demonstrating their biological drug transporting activities. Data comparing different methods of investigating expression of mdr mRNAs and their corresponding proteins are still scarce. In this article we present the results of a study concerning mdr mRNA and protein expression. Our goal was to search for the best method to investigate the expression level and functional activity of five selected mdr proteins—MDR1, BCRP, MRP1, MRP4 and MRP5—in established in vitro cell lines of human endothelial cells (ECs) and their progenitors. Endothelial cells demonstrated mdr presence at the mRNA level, which was not always confirmed at the protein level or in functional tests. Therefore, several different assays had to be applied for evaluation of mdr proteins expression and functions in endothelial cells. Among them functional tests seemed to be the most conclusive, although not very specific. PMID:28212450

  15. 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.

  16. Phospholipid-modified PEI-based nanocarriers for in vivo siRNA therapeutics against multidrug-resistant tumors.

    PubMed

    Essex, S; Navarro, G; Sabhachandani, P; Chordia, A; Trivedi, M; Movassaghian, S; Torchilin, V P

    2015-03-01

    Multidrug resistance (MDR) mediated by P-glycoprotein overexpression in solid tumors is a major factor in the failure of many forms of chemotherapy. Here we evaluated phospholipid-modified, low-molecular-weight polyethylenimine (DOPE-PEI) nanocarriers for intravenous delivery of anti-P-pg siRNA to tumors with the final goal of modulating MDR in breast cancer. First, we studied the biodistribution of DOPE-PEI nanocarriers and the effect of PEG coating in a subcutaneous breast tumor model. Four hours postinjection, PEGylated carriers showed an 8% injected dose (ID) accumulation in solid tumor via the enhanced permeability and retention effect and 22% ID in serum due to a prolonged, PEG-mediated circulation. Second, we established the therapeutic efficacy and safety of DOPE-PEI/siRNA-mediated P-gp downregulation in combination with doxorubicin (Dox) chemotherapy in MCF-7/MDR xenografts. Weekly injection of siRNA nanopreparations and Dox for up to 5 weeks sensitized the tumors to otherwise non-effective doses of Dox and decreased the tumor volume by threefold vs controls. This therapeutic improvement in response to Dox was attributed to the significant, sequence-specific P-gp downregulation in excised tumors mediated by the DOPE-PEI formulations.

  17. Nonthermal atmospheric plasma rapidly disinfects multidrug-resistant microbes by inducing cell surface damage.

    PubMed

    Kvam, Erik; Davis, Brian; Mondello, Frank; Garner, Allen L

    2012-04-01

    Plasma, a unique state of matter with properties similar to those of ionized gas, is an effective biological disinfectant. However, the mechanism through which nonthermal or "cold" plasma inactivates microbes on surfaces is poorly understood, due in part to challenges associated with processing and analyzing live cells on surfaces rather than in aqueous solution. Here, we employ membrane adsorption techniques to visualize the cellular effects of plasma on representative clinical isolates of drug-resistant microbes. Through direct fluorescent imaging, we demonstrate that plasma rapidly inactivates planktonic cultures, with >5 log(10) kill in 30 s by damaging the cell surface in a time-dependent manner, resulting in a loss of membrane integrity, leakage of intracellular components (nucleic acid, protein, ATP), and ultimately focal dissolution of the cell surface with longer exposure time. This occurred with similar kinetic rates among methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Candida albicans. We observed no correlative evidence that plasma induced widespread genomic damage or oxidative protein modification prior to the onset of membrane damage. Consistent with the notion that plasma is superficial, plasma-mediated sterilization was dramatically reduced when microbial cells were enveloped in aqueous buffer prior to treatment. These results support the use of nonthermal plasmas for disinfecting multidrug-resistant microbes in environmental settings and substantiate ongoing clinical applications for plasma devices.

  18. A novel curcumin derivative which inhibits P-glycoprotein, arrests cell cycle and induces apoptosis in multidrug resistance cells.

    PubMed

    Lopes-Rodrigues, Vanessa; Oliveira, Ana; Correia-da-Silva, Marta; Pinto, Madalena; Lima, Raquel T; Sousa, Emília; Vasconcelos, M Helena

    2017-01-15

    Cancer multidrug resistance (MDR) is a major limitation to the success of cancer treatment and is highly associated with the overexpression of drug efflux pumps such as P-glycoprotein (P-gp). In order to achieve more effective chemotherapeutic treatments, it is important to develop P-gp inhibitors to block/decrease its activity. Curcumin (1) is a secondary metabolite isolated from the turmeric of Curcuma longa L.. Diverse biological activities have been identified for this compound, particularly, MDR modulation in various cancer cell models. However, curcumin (1) has low chemical stability, which severely limits its application. In order to improve stability and P-gp inhibitory effect, two potential more stable curcumin derivatives were synthesized as building blocks, followed by several curcumin derivatives. These compounds were then analyzed in terms of antitumor and anti-P-gp activity, in two MDR and sensitive tumor lines (from chronic myeloid leukemia and non-small cell lung cancer). We identified from a series of curcumin derivatives a novel curcumin derivative (1,7-bis(3-methoxy-4-(prop-2-yn-1-yloxy)phenyl)hepta-1,6-diene-3,5-dione, 10) with more potent antitumor and anti-P-gp activity than curcumin (1). This compound (10) was shown to promote cell cycle arrest (at the G2/M phase) and induce apoptosis in the MDR chronic myeloid leukemia cell line. Therefore it is a really interesting P-gp inhibitor due to its ability to inhibit both P-gp function and expression.

  19. The Effects and Mechanisms of Periplaneta americana Extract Reversal of Multi-Drug Resistance in BEL-7402/5-FU Cells.

    PubMed

    Yuan, Falu; Liu, Junyong; Qiao, Tingting; Li, Ting; Shen, Qi; Peng, Fang

    2016-06-28

    The present study reports the reversing effects of extracts from P. americana on multidrug resistance of BEL-7402/5-FU cells, as well as a preliminary investigation on their mechanism of action. A methylthiazolyl tetrazolium (MTT) method was applied to determine the multidrug resistance of BEL-7402/5-FU, while an intracellular drug accumulation assay was used to evaluate the effects of a column chromatography extract (PACC) and defatted extract (PADF) from P. americana on reversing multi-drug resistance. BEL-7402/5-FU reflected high resistance to 5-FU; PACC and PADF could promote drug accumulation in BEL-7402/5-FU cells, among which PADF was more effective than PACC. Moreover, results from the immunocytochemical method showed that PACC and PADF could downregulate the expression of drug resistance-associated proteins (P-gp, MRP, LRP); PACC and PADF had no effects on the expression of multidrug resistance-associated enzymes (GST-π), but PACC could increase the expression of multidrug resistance-associated enzymes (PKC). Results of real-time fluorescence quantitative PCR revealed that PACC and PADF were able to markedly inhibit the expression of multidrug resistance-associated genes (MDR1, LRP and MRP1); PACC presented a significant impact on the gene expression of multidrug resistance-associated enzymes, which increased the gene expression of GST-π and PKC. However, PADF had little impact on the expression of multidrug resistance-associated enzymes. These results demonstrated that PACC and PADF extracted from P. americana could effectively reverse MDR in BEL-7402/5-FU cells, whose mechanism was to inhibit the expression of P-gp, MRP, and LRP, and that PADF was more effective in the reversal of MDR than did PACC. In addition, some of extracts from P. americana altered (sometimes increasing) the expression of multidrug resistance-associated enzymes.

  20. Cell Type Dependent Regulation of Multidrug Resistance-1 Gene Expression by AML1-ETO

    PubMed Central

    Hines, Robert; Boyapati, Anita; Zhang, Dong-Er

    2007-01-01

    The AML1-ETO fusion protein is generated from the 8;21 chromosome translocation that is commonly identified in acute myeloid leukemia. AML1-ETO is a DNA binding transcription factor and has been demonstrated to play a critical role in promoting leukemogenesis. Therefore, it is important to define the molecular mechanism of AML1-ETO in the regulation of gene expression. Here, we report that the effect of AML1-ETO on the promoter of multidrug resistance-1 (MDR1) gene, a known AML1-ETO target, is highly cell type specific. Besides observing repression of the MDR1 promoter in C33A and CV-1 cells as reported previously, AML1-ETO strongly activated the promoter in K562 and B210 cells. More importantly, this activation required both the AML1 and ETO portions of the fusion protein, but did not depend on the AML1 binding site in MDR1 promoter. Furthermore, results from promoter deletion analysis and chromatin immunoprecipitation assays suggested that this activation effect was likely through the influence of the general transcription machinery rather than promoter-specific factors. Based on these data, we propose that AML1-ETO may have opposing effects on gene expression depending on the various conditions of the cellular environment. PMID:17590361

  1. Psoralen reverses docetaxel-induced multidrug resistance in A549/D16 human lung cancer cells lines.

    PubMed

    Hsieh, Ming-Ju; Chen, Mu-Kuan; Yu, Ya-Yen; Sheu, Gwo-Tarng; Chiou, Hui-Ling

    2014-06-15

    Chemotherapy is the recommended treatment for advanced-stage cancers. However, the emergence of multidrug resistance (MDR), the ability of cancer cells to become simultaneously resistant to different drugs, limits the efficacy of chemotherapy. Previous studies have shown that herbal medicine or natural food may be feasible for various cancers as potent chemopreventive drug. This study aims to explore the capablility of reversing the multidrug resistance of docetaxel (DOC)-resistant A549 cells (A549/D16) of psoralen and the underlying mechanisms. In this study, results showed that the cell viability of A549/D16 subline is decreased when treated with psoralen plus DOC, while psoralen has no effect on the cell proliferation on A549 and A549/D16 cells. Furthermore, mRNA and proteins levels of ABCB1 were decreased in the presence of psoralen, while decreased ABCB1 activity was also revealed by flow cytometry. Based on these results, we believe that psoralen may be feasible for reversing the multidrug resistance by inhibiting ABCB1 gene and protein expression. Such inhibition will lead to a decrease in ABCB1 activity and anti-cancer drug efflux, which eventually result in drug resistance reversal and therefore, sensitizing drug-resistant cells to death in combination with chemotherapeutic drugs.

  2. Rack1 Mediates the Interaction of P-Glycoprotein with Anxa2 and Regulates Migration and Invasion of Multidrug-Resistant Breast Cancer Cells

    PubMed Central

    Yang, Yi; Wu, Na; Wang, Zhiyong; Zhang, Fei; Tian, Ran; Ji, Wei; Ren, Xiubao; Niu, Ruifang

    2016-01-01

    The emergence of multidrug resistance is always associated with more rapid tumor recurrence and metastasis. P-glycoprotein (P-gp), which is a well-known multidrug-efflux transporter, confers enhanced invasion ability in drug-resistant cells. Previous studies have shown that P-gp probably exerts its tumor-promoting function via protein-protein interaction. These interactions were implicated in the activation of intracellular signal transduction. We previously showed that P-gp binds to Anxa2 and promotes the invasiveness of multidrug-resistant (MDR) breast cancer cells through regulation of Anxa2 phosphorylation. However, the accurate mechanism remains unclear. In the present study, a co-immunoprecipitation coupled with liquid chromatography tandem mass spectrometry-based interactomic approach was performed to screen P-gp binding proteins. We identified Rack1 as a novel P-gp binding protein. Knockdown of Rack1 significantly inhibited proliferation and invasion of MDR cancer cells. Mechanistic studies demonstrated that Rack1 functioned as a scaffold protein that mediated the binding of P-gp to Anxa2 and Src. We showed that Rack1 regulated P-gp activity, which was necessary for adriamycin-induced P-gp-mediated phosphorylation of Anxa2 and Erk1/2. Overall, the findings in this study augment novel insights to the understanding of the mechanism employed by P-gp for promoting migration and invasion of MDR cancer cells. PMID:27754360

  3. Fulvestrant reverses doxorubicin resistance in multidrug-resistant breast cell lines independent of estrogen receptor expression.

    PubMed

    Huang, Yuan; Jiang, Donghai; Sui, Meihua; Wang, Xiaojia; Fan, Weimin

    2017-02-01

    Drug resistance, a major obstacle to successful cancer chemotherapy, frequently occurs in recurrent or metastatic breast cancer and results in poor clinical response. Fulvestrant is a new type of selective estrogen receptor (ER) downregulator and a promising endocrine therapy for breast cancer. In this study, we evaluated the combination treatment of fulvestrant and doxorubicin in ER-negative multidrug-resistant (MDR) breast cancer cell lines Bads‑200 and Bats‑72. Fulvestrant potentiated doxorubicin-induced cytotoxicity, apoptosis and G2/M arrest with upregulation of cyclin B1. It functioned as a substrate for P-glycoprotein (P-gp) without affecting its expression. Furthermore, fulvestrant not only restored the intracellular accumulation of doxorubicin but also relocalized it to the nuclei in Bats‑72 and Bads‑200 cells, which may be another potential mechanism of reversal of P-gp mediated doxorubicin resistance. These results indicated that the combination of fulvestrant and doxorubicin-based chemotherapy may be feasible and effective for patients with advanced breast cancer.

  4. A role for multidrug resistance protein 4 (MRP4; ABCC4) in human dendritic cell migration

    PubMed Central

    van de Ven, Rieneke; Scheffer, George L.; Reurs, Anneke W.; Lindenberg, Jelle J.; Oerlemans, Ruud; Jansen, Gerrit; Gillet, Jean-Pierre; Glasgow, Joel N.; Pereboev, Alexander; Curiel, David T.; Scheper, Rik J.

    2008-01-01

    The capacity of dendritic cells (DCs) to migrate from peripheral organs to lymph nodes (LNs) is important in the initiation of a T cell–mediated immune response. The ATP-binding cassette (ABC) transporters P-glycoprotein (P-gp; ABCB1) and the multidrug resistance protein 1 (MRP1; ABCC1) have been shown to play a role in both human and murine DC migration. Here we show that a more recently discovered family member, MRP4 (ABCC4), is expressed on both epidermal and dermal human skin DCs and contributes to the migratory capacity of DCs. Pharmacological inhibition of MRP4 activity or down-regulation through RNAi in DCs resulted in reduced migration of DCs from human skin explants and of in vitro generated Langerhans cells. The responsible MRP4 substrate remains to be identified as exogenous addition of MRP4's known substrates prostaglandin E2, leukotriene B4 and D4, or cyclic nucleotides (all previously implicated in DC migration) could not restore migration. This notwithstanding, our data show that MRP4 is an important protein, significantly contributing to human DC migration toward the draining lymph nodes, and therefore relevant for the initiation of an immune response and a possible target for immunotherapy. PMID:18625884

  5. Reversal of multidrug resistance in cancer cells by novel asymmetrical 1,4-dihydropyridines.

    PubMed

    Firuzi, Omidreza; Javidnia, Katayoun; Mansourabadi, Elham; Saso, Luciano; Mehdipour, Ahmad Reza; Miri, Ramin

    2013-11-01

    Multidrug resistance (MDR) is an important obstacle that limits the efficacy of chemotherapy in many types of cancer. In this study, 14 novel asymmetrical DHPs possessing pyridyl alkyl carboxylate substitutions at C3 and alkyl carboxylate groups at C5 in addition to a nitroimidazole or nitrophenyl moiety at C4 position were synthesized. Calcium channel blocking (CCB) activity was measured in guinea pig ileal longitudinal smooth muscle. Cytotoxicity was tested on 4 human cancer cell lines, while MDR reversal capacity was examined on P-glycoprotein overexpressing doxorubicin resistant MES-SA-DX5 and compared with non-resistant MES-SA cells. Compounds showed different CCB (IC50: 29.3 nM-4.75 μM) and cytotoxic activities (IC50: 6.4 to more than 100 μM). Several compounds having nitrophenyl moiety at C4, could significantly reverse resistance to doxorubicin at 0.5 and 1 μM. The most active ones were 7e and 7g containing ethyl carboxylate and isopropyl carboxylate at C5, respectively. CCB activity, which is considered an undesirable effect for these agents, of 7e and 7g were 33 and 20 times lower than nifedipine, respectively. In conclusion, the newly synthesized asymmetrical DHP compounds showed promising MDR reversal and antitumoral activities with low CCB effects and could be of therapeutic value in drug resistant cancer.

  6. An AS1411 aptamer-conjugated liposomal system containing a bubble-generating agent for tumor-specific chemotherapy that overcomes multidrug resistance.

    PubMed

    Liao, Zi-Xian; Chuang, Er-Yuan; Lin, Chia-Chen; Ho, Yi-Cheng; Lin, Kun-Ju; Cheng, Po-Yuan; Chen, Ko-Jie; Wei, Hao-Ji; Sung, Hsing-Wen

    2015-06-28

    Recent research in chemotherapy has prioritized overcoming the multidrug resistance (MDR) of cancer cells. In this work, liposomes that contain doxorubicin (DOX) and ammonium bicarbonate (ABC, a bubble-generating agent) are prepared and functionalized with an antinucleolin aptamer (AS1411 liposomes) to target DOX-resistant breast cancer cells (MCF-7/ADR), which overexpress nucleolin receptors. Free DOX and liposomes without functionalization with AS1411 (plain liposomes) were used as controls. The results of molecular dynamic simulations suggest that AS1411 functionalization may promote the affinity and specific binding of liposomes to the nucleolin receptors, enhancing their subsequent uptake by tumor cells, whereas plain liposomes enter cells with difficulty. Upon mild heating, the decomposition of ABC that is encapsulated in the liposomes enables the immediate activation of generation of CO2 bubbles, creating permeable defects in their lipid bilayers, and ultimately facilitating the swift intracellular release of DOX. In vivo studies in nude mice that bear tumors demonstrate that the active targeting of AS1411 liposomes can substantially increase the accumulation of DOX in the tumor tissues relative to free DOX or passively targeted plain liposomes, inhibiting tumor growth and reducing systemic side effects, including cardiotoxicity. The above findings indicate that liposomes that are functionalized with AS1411 represent an attractive therapeutic alternative for overcoming the MDR effect, and support a potentially effective strategy for cancer therapy.

  7. Natural paniceins from mediterranean sponge inhibit the multidrug resistance activity of Patched and increase chemotherapy efficiency on melanoma cells

    PubMed Central

    Fiorini, Laura; Tribalat, Marie-Aude; Sauvard, Lucy; Cazareth, Julie; Lalli, Enzo; Broutin, Isabelle; Thomas, Olivier P.; Mus-Veteau, Isabelle

    2015-01-01

    Multidrug resistance has appeared to mitigate the efficiency of anticancer drugs and the possibility of successful cancer chemotherapy. The Hedgehog receptor Patched is a multidrug transporter expressed in several cancers and as such it represents a new target to circumvent chemotherapy resistance. We report herein that paniceins and especially panicein A hydroquinone, natural meroterpenoids produced by the Mediterranean sponge Haliclona (Soestella) mucosa, inhibit the doxorubicin efflux activity of Patched and enhance the cytotoxicity of this chemotherapeutic agent on melanoma cells in vitro. These results are supported by the molecular docking performed on the structure of the bacterial drug efflux pump AcrB and on the Patched model built from AcrB structure. Docking calculations show that panicein A hydroquinone interacts with AcrB and Patched model close to the doxorubicin binding site. This compound thus appears as the first antagonist of the doxorubicin efflux activity of Patched. The use of inhibitors of Patched drug efflux activity in combination with classical chemotherapy could represent a novel approach to reduce tumor drug resistance, recurrence and metastasis. PMID:26068979

  8. Curcumin promotes apoptosis in A549/DDP multidrug-resistant human lung adenocarcinoma cells through an miRNA signaling pathway

    SciTech Connect

    Zhang, Jian; Zhang, Tao; Ti, Xinyu; Shi, Jieran; Wu, Changgui; Ren, Xinling; Yin, Hong

    2010-08-13

    Research highlights: {yields} Curcumin had anti-cancer effects on A549/DDP multidrug-resistant human lung adenocarcinoma cells {yields} Curcumin promotes apoptosis in A549/DDP cells through a miRNA signaling pathway {yields} Curcumin induces A549/DDP cell apoptosis by downregulating miR-186* {yields} miR-186* may serve as a potential gene therapy target for refractory lung cancer that is sensitive to curcumin -- Abstract: Curcumin extracted from the rhizomes of Curcuma longa L. has been shown to have inhibitory effects on cancers through its anti-proliferative and pro-apoptotic activities. Emerging evidence demonstrates that curcumin can overcome drug resistance to classical chemotherapies. Thus, the mechanisms underlying the anti-tumor activities of curcumin require further study. In our study, we first demonstrated that curcumin had anti-cancer effects on A549/DDP multidrug-resistant human lung adenocarcinoma cells. Further studies showed that curcumin altered miRNA expression; in particular, significantly downregulated the expression of miR-186* in A549/DDP. In addition, transfection of cells with a miR-186* inhibitor promoted A549/DDP apoptosis, and overexpression of miR-186* significantly inhibited curcumin-induced apoptosis in A549/DDP cells. These observations suggest that miR-186* may serve as a potential gene therapy target for refractory lung cancer that is sensitive to curcumin.

  9. Genes amplified and overexpressed in human multidrug-resistant cell lines.

    PubMed

    Van der Bliek, A M; Baas, F; Van der Velde-Koerts, T; Biedler, J L; Meyers, M B; Ozols, R F; Hamilton, T C; Joenje, H; Borst, P

    1988-11-01

    Multidrug resistance (MDR) is associated with overproduction of Mr 170,000 membrane proteins (P-glycoproteins) caused by either gene amplification, transcriptional activation, or both. In rodents the amplified domain comprises genes that encode P-glycoproteins and at least five unrelated genes, one of which encodes the calcium-binding protein sorcin. The amplification and increased expression of these genes always includes one P-glycoprotein-encoding gene (pgp1 in hamsters, homologous to mdr1 in humans). In human MDR cells only elevated mdr1 expression has been shown thusfar, although another P-glycoprotein encoding gene (mdr3, homologous to hamster pgp3) is closely linked. Here we show that the human homolog of the hamster sorcin gene resides on chromosome 7 like the P-glycoprotein-encoding genes. Furthermore, gene classes designated 4, 5, and 6 are coamplified with mdr1 and mdr3 in the human ovarian carcinoma cell line 2780AD, which strongly suggests that the overall structure of the human MDR domain is the same as in rodents. Class 6 was moderately and mdr1 was highly overexpressed in this cell line. Four other human MDR cell lines also have much higher mdr1 overexpression than expected from the relatively low levels (2- to 30-fold) of gene amplification. This contrasts with the results of previous work with rodent MDR cells, in which the increase in P-glycoprotein mRNA levels usually parallels the increase in gene copy number. Although four of the five human MDR cell lines have coamplified mdr3, its expression was undetectable. Our results confirm the central role of the mdr1 (pgp1) gene in MDR and suggest that different cross-resistance patterns are not due to differential expression of different P-glycoprotein genes.

  10. Knockdown of HOXA10 reverses the multidrug resistance of human chronic mylogenous leukemia K562/ADM cells by downregulating P-gp and MRP-1.

    PubMed

    Yi, Ying-Jie; Jia, Xiu-Hong; Wang, Jian-Yong; Li, You-Jie; Wang, Hong; Xie, Shu-Yang

    2016-05-01

    Multidrug resistance (MDR) of leukemia cells is a major obstacle in chemotherapeutic treatment. The high expression and constitutive activation of P-glycoprotein (P-gp) and multidrug resistance protein-1 (MRP-1) have been reported to play a vital role in enhancing cell resistance to anticancer drugs in many tumors. The present study aimed to investigate the reversal of MDR by silencing homeobox A10 (HOXA10) in adriamycin (ADR)-resistant human chronic myelogenous leukemia (CML) K562/ADM cells by modulating the expression of P-gp and MRP-1. K562/ADM cells were stably transfected with HOXA10-targeted short hairpin RNA (shRNA). The results of reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis showed that the mRNA and protein expression of HOXA10 was markedly suppressed following transfection with a shRNA-containing vector. The sensitivity of the K562/ADM cells to ADR was enhanced by the silencing of HOXA10, due to the increased intracellular accumulation of ADR. The accumulation of ADR induced by the silencing of HOXA10 may be due to the downregulation of P-gp and MRP-1. Western blot analysis revealed that downregulating HOXA10 inhibited the protein expression of P-gp and MRP-1. Taken together, these results suggest that knockdown of HOXA10 combats resistance and that HOXA10 is a potential target for resistant human CML.

  11. Amplicon structure in multidrug-resistant murine cells: a nonrearranged region of genomic DNA corresponding to large circular DNA.

    PubMed Central

    Ståhl, F; Wettergren, Y; Levan, G

    1992-01-01

    Multidrug resistance (MDR) in tumor cell lines is frequently correlated with amplification of one or more mdr genes. Usually the amplified domain also includes several neighboring genes. Using pulsed-field gel electrophoresis, we have established a restriction map covering approximately 2,200 kb in the drug-sensitive mouse tumor cell line TC13K. The mapped region is located on mouse chromosome 5 and includes the three mdr genes, the gene for the calcium-binding sorcin protein, and a gene with unknown function designated class 5. Long-range maps of the amplified DNA sequences in five of six MDR sublines that had been independently derived from TC13K generally displayed the same pattern as did the parental cell line. All six MDR sublines exhibited numerous double minutes, and one of them displayed a homogeneously staining region in a subpopulation. Large circular molecules, most likely identical to one chromatid of the double minutes, were detected in four of the sublines by linearization with gamma irradiation. The size of the circles was about 2,500 kb, which correlated to a single unit of the amplified domain. We therefore propose that in four independent instances of MDR development, a single unit of about 2,500 kb has been amplified in the form of circular DNA molecules. The restriction enzyme map of the amplified unit is unchanged compared with that of the parental cell line, whereas the joining sites of the circular DNA molecules are not identical but are in the same region. Images PMID:1545798

  12. Cytotoxic and multidrug resistance reversal activities of novel 1,4-dihydropyridines against human cancer cells.

    PubMed

    Shekari, Farnaz; Sadeghpour, Hossein; Javidnia, Katayoun; Saso, Luciano; Nazari, Farhad; Firuzi, Omidreza; Miri, Ramin

    2015-01-05

    Multidrug resistance (MDR) caused by P-glycoprotein (P-gp, ABCB1, MDR-1) transporter over-expression in cancer cells substantially limits the effectiveness of chemotherapy. 1,4-Dihydropyridines (DHPs) derivatives possess several pharmacological activities. In this study, 18 novel asymmetrical DHPs bearing 3-pyridyl methyl carboxylate and alkyl carboxylate moieties at C₃ and C₅ positions, respectively, as well as nitrophenyl or hetero aromatic rings at C₄ were synthesized and tested for MDR reversal with the aim of establishing a structure-activity relationship (SAR) for these agents. Effect of these compounds on P-gp mediated MDR was assessed in P-gp over-expressing MES-SA/DX5 doxorubicin resistant cells by flow cytometric detection of rhodamine 123 efflux. MDR reversal was further examined as the alteration of doxorubicin׳s IC₅₀ in MES-SA/DX5 cells in the presence of DHPs by MTT assay and was compared to nonresistant MES-SA cells. Direct anticancer effect was examined against 4 human cancer cells including HL-60, K562, MCF-7 and LS180. Calcium channel blocking (CCB) activity was also measured as a potential side effect. Most DHPs, particularly compounds bearing 3-nitrophenyl (A2B2 and A3B2) and 4-nitrophenyl (A3B1 and A4B1) moieties at C₄ significantly inhibited rhodamine 123 efflux at 5-25 µM, showing that the mechanism of MDR reversal by these agents is P-gp transporter modulation. Same derivatives were also able to selectively lower the resistance of MES-SA/DX5 to doxorubicin. A2B2 bearing ethyl carboxylate at C₅ had also high direct antitumoral effect (IC₅₀ range: 3.77-15.60 μM). Our findings suggest that SAR studies of DHPs may lead to the discovery of novel MDR reversal agents.

  13. Molecular evidence and functional expression of multidrug resistance associated protein (MRP) in rabbit corneal epithelial cells.

    PubMed

    Karla, Pradeep K; Pal, Dananjay; Mitra, Ashim K

    2007-01-01

    Multidrug resistance associated protein (MRP) is a major family of efflux transporters involved in drug efflux leading to drug resistance. The objective of this study was to explore physical barriers for ocular drug absorption and to verify if the role of efflux transporters. MRP-2 is a major homologue of MRP family and found to express on the apical side of cell membrane. Cultured Rabbit Corneal Epithelial Cells (rCEC) were selected as an in vitro model for corneal epithelium. [14C]-erythromycin which is a proven substrate for MRP-2 was selected as a model drug for functional expression studies. MK-571, a known specific and potent inhibitor for MRP-2 was added to inhibit MRP mediated efflux. Membrane fraction of rCEC was used for western blot analysis. Polarized transport of [14C]-erythromycin was observed in rCEC and transport from B-->A was significantly high than from A-->B. Permeability's increased significantly from A-->B in the presence of MK-571 and ketoconozole. Uptake of [14C]-erythromycin in the presence of MK-571 was significantly higher than control in rCEC. RT-PCR analysis indicated a unique and distinct band at approximately 498 bp corresponding to MRP-2 in rCEC and MDCK11-MRP-2 cells. Immunoprecipitation followed by Western Blot analysis indicated a specific band at approximately 190 kDa in membrane fraction of rCEC and MDCK11-MRP-2 cells. For the first time we have demonstrated high expression of MRP-2 in rabbit corneal epithelium and its functional activity causing drug efflux. RT-PCR, immunoprecipitation followed by Western blot analysis further confirms the result.

  14. Effects of hypergravity on the expression of multidrug resistance proteins in human melanocytic cells

    NASA Astrophysics Data System (ADS)

    Lambers, B.; Stieber, C.; Grigorieva, O.; Block, I.; Bromeis, B.; Buravkova, L.; Gerzer, R.; Ivanova, K.

    In humans the skin serves as a barrier against potentially harmful effects of the environment Human melanocytes constitute the principal cells for skin pigmentation by synthesizing the pigment melanin Melanin acts as a scavenger for free radicals that may arise during metabolic stress The melanocytes are also able to secrete a wide range of signal molecules In previous studies we found that normal human melanocytes NHMs and non-metastatic melanoma cells respond to long-time exposure to hypergravity up to 5 g for 24 h with elevated efflux of guanosine 3 5 -cyclic monophosphate cGMP in the presence of phosphodiesterase PDE inhibitors e g 3-isobutyl-1-methylxanthine Cyclic GMP is known to play a signaling role in human melanocyte physiology It controls the signaling activities of nitric oxide NO in relation to melanogenesis as well as in melanocyte-extracellular matrix interactions that may be important for some pathological processes including metastasis The present study investigated the effects of hypergravity on the expression of the multidrug resistance proteins MRP 4 and 5 as highly selective cGMP exporters in non-stimulated and NO-stimulated NHMs and melanoma cells MCs on mRNA levels using semi-quantitative RT-PCR analysis Hypergravity up to 5 g for 24 h was produced by horizontal centrifugal acceleration The NONOate DETA-NO 0 1 mM was used as a direct NO donor for cell stimulation For 5-g experiments the mRNA levels for the highly specific cGMP transporter MRP5 appeared to be

  15. Fallopia japonica, a Natural Modulator, Can Overcome Multidrug Resistance in Cancer Cells

    PubMed Central

    Eid, Safaa Yehia; El-Readi, Mahmoud Zaki; Ashour, Mohamed Lotfy; Wink, Michael

    2015-01-01

    Resistance of cancer cells to chemotherapy is controlled by the decrease of intracellular drug accumulation, increase of detoxification, and diminished propensity of cancer cells to undergo apoptosis. ATP-binding cassette (ABC) membrane transporters with intracellular metabolic enzymes contribute to the complex and unresolved phenomenon of multidrug resistance (MDR). Natural products as alternative medicine have great potential to discover new MDR inhibitors with diverse modes of action. In this study, we characterized several extracts of traditional Chinese medicine (TCM) plants (N = 16) for their interaction with ABC transporters, cytochrome P3A4 (CYP3A4), and glutathione-S-transferase (GST) activities and their cytotoxic effect on different cancer cell lines. Fallopia japonica (FJ) (Polygonaceae) shows potent inhibitory effect on CYP3A4 P-glycoprotein activity about 1.8-fold when compared to verapamil as positive control. FJ shows significant inhibitory effect (39.81%) compared with the known inhibitor ketoconazole and 100 μg/mL inhibited GST activity to 14 μmol/min/mL. FJ shows moderate cytotoxicity in human Caco-2, HepG-2, and HeLa cell lines; IC50 values were 630.98, 198.80, and 317.37 µg/mL, respectively. LC-ESI-MS were used to identify and quantify the most abundant compounds, emodin, polydatin, and resveratrol, in the most active extract of FJ. Here, we present the prospect of using Fallopia japonica as natural products to modulate the function of ABC drug transporters. We are conducting future study to evaluate the ability of the major active secondary metabolites of Fallopia japonica to modulate MDR and their impact in case of failure of chemotherapy. PMID:26346937

  16. Silencing of long non-coding RNA ANRIL inhibits the development of multidrug resistance in gastric cancer cells.

    PubMed

    Lan, Wei-Guang; Xu, Dian-Hong; Xu, Chen; Ding, Chang-Ling; Ning, Fang-Ling; Zhou, Yan-Li; Ma, Long-Bo; Liu, Chang-Min; Han, Xia

    2016-07-01

    The development of multidrug resistance (MDR) is a crucial cause of therapy failure in gastric cancer, which results in disease recurrence and metastasis. Long non-coding RNAs (lncRNAs) have been proven to be critical in carcinogenesis and metastasis of gastric cancer. However, little is known about the roles of ANRIL (antisense non-coding RNA in the INK4 locus) in gastric cancer MDR. The aim of our study is to identify the biological function of ANRIL in gastric cancer MDR. In our results, ANRIL was highly expressed in gastric cancer tissues of cisplatin-resistant and 5-fluorouracil (5-FU)-resistant patients, and the same upregulation trends were observed in cisplatin-resistant cells (BGC823/DDP) and 5-FU-resistant cells (BGC823/5-FU). In addition, BGC823/DDP and BGC823/5-FU cells transfected with ANRIL siRNA and treated with cisplatin or 5-FU, respectively, exhibited significant lower survival rate, decreased invasion capability, and high percentage of apoptotic tumor cells. The influence of ANRIL knockdown on MDR was assessed by measuring IC50 of BGC823/DDP and BGC823/5-FU cells to cisplatin and 5-FU, the result showed that silencing ANRIL decreased the IC50 values in gastric cancer cells. Moreover, qRT-PCR and western blotting revealed that ANRIL knockdown decreased the expression of MDR1 and MRP1, both of which are MDR related genes; regression analysis showed that the expression of ANRIL positively correlated with the expression of MDR1 and MRP1, resprectively In summary, knockdown of lncRNA ANRIL in gastric cancer cells inhibits the development of MDR, suggesting an efficacious target for reversing MDR in gastric cancer therapy.

  17. [Cytological Study in vitro on Co-delivery of siRNA and Paclitaxel within Solid Lipid Nanoparticles to Overcome Multidrug Resistance in Tumors].

    PubMed

    Huang, Rui; Yao, Xinyu; Chen, Yuan; Sun, Xun; Lin, Yunzhu

    2016-02-01

    Multidrug resistance (MDR) remains the major obstacle to the success of clinical cancer chemotherapy. P-glycoprotein (P-gp), encoded by the MDR1, is an important part with complex mechanisms associated with the MDR. In order to overcome the MDR of tumors, we in the present experimental design incorporated small interfering RNA (siRNA) targeting MDR1 gene and anticancer drug paclitaxel (PTX) into the solid lipid nanoparticles (SLNs) to achieve the combinational therapeutic effects of genetherapy and chemotherapy. In this study, siRNA-PTX-SLNs were successfully prepared. The cytotoxicity of blank SLNs and siRNA-PTX-SLNs in MCF-7 cells and MCF-7/ADR cells were detected by MTT; and the uptake efficiency of PTX in MCF-7/ADR cells were detected via HPLC method; quantitative real-time PCR and flow cytometry were performed to investigate the silencing effect of siRNA-PTX- SLNs on MDR1 gene in MCF-7/ADR cells. The results showed that PTX loaded SLNs could significantly inhibit the growth of tumor cells, and more importantly, the MDR tumor cells treated with siRNA-PTX-SLNs showed the lowest viability. HPLC study showed that SLNs could enhance the cellular uptake for PTX. Meanwhile, siRNA delivered by SLNs significantly decreased the P-gp expression in MDR tumor cells, thus increased the cellular accumulation of rhodamine123 as a P-gp substrate. In conclusion, the MDR1 gene could be silenced by siRNA-PTX-SLNs, which could promote the growth inhibition efficiency of PTX on tumor cells, leading to synergetic effect on MDR tumor therapy.

  18. Effect of Prostaglandin E2 on Multidrug Resistance Transporters In Human Placental Cells

    PubMed Central

    Lee, Gene T.; Dong, Yafeng; Zhou, Helen; He, Lily; Weiner, Carl P.

    2014-01-01

    Prostaglandin (PG) E2, a major product of cyclooxygenase (COX)-2, acts as an immunomodulator at the maternal-fetal interface during pregnancy. It exerts biologic function through interaction with E-prostanoid (EP) receptors localized to the placenta. The activation of the COX-2/PGE2/EP signal pathway can alter the expression of the ATP-binding cassette (ABC) transporters, multidrug resistance protein 1 [P-glycoprotein (Pgp); gene: ABCB1], and breast cancer resistance protein (BCRP; gene: ABCG2), which function to extrude drugs and xenobiotics from cells. In the placenta, PGE2-mediated changes in ABC transporter expression could impact fetal drug exposure. Furthermore, understanding the signaling cascades involved could lead to strategies for the control of Pgp and BCRP expression levels. We sought to determine the impact of PGE2 signaling mechanisms on Pgp and BCRP in human placental cells. The treatment of placental cells with PGE2 up-regulated BCRP expression and resulted in decreased cellular accumulation of the fluorescent substrate Hoechst 33342. Inhibiting the EP1 and EP3 receptors with specific antagonists attenuated the increase in BCRP. EP receptor signaling results in activation of transcription factors, which can affect BCRP expression. Although PGE2 decreased nuclear factor κ-light chain-enhancer of activated B activation and increased activator protein 1, chemical inhibition of these inflammatory transcription factors did not blunt BCRP up-regulation by PGE2. Though PGE2 decreased Pgp mRNA, Pgp expression and function were not significantly altered. Overall, these findings suggest a possible role for PGE2 in the up-regulation of placental BCRP expression via EP1 and EP3 receptor signaling cascades. PMID:25261564

  19. NF-κB decoy polyplexes decrease P-glycoprotein-mediated multidrug resistance in colorectal cancer cells.

    PubMed

    Abd Ellah, N H; Taylor, L; Ayres, N; Elmahdy, M M; Fetih, G N; Jones, H N; Ibrahim, E A; Pauletti, G M

    2016-05-01

    Multidrug resistance (MDR), a major cause for chemotherapy failure, has been linked to upregulation of ATP-dependent membrane efflux systems that limit intracellular accumulation of cytotoxic anticancer agents. P-glycoprotein (P-gp) encoded by the human ABCB1 gene was the first efflux transporter identified to contribute to MDR. ABCB1 gene expression is correlated with constitutive activation of the NF-κB signaling pathway in tumor cells. The objective of this research is to modulate P-gp activity in colon cancer cells using NF-κB decoy oligodeoxynucleotides (ODNs) that are effectively delivered into the nucleus of colorectal cancer cells by self-assembling nonviral nanoparticles comprising the novel poly[N-(2-hydroxypropyl)methacrylamide]-poly(N,N-dimethylaminoethylmethacrylate) diblock copolymer (pHPMA-b-pDMAEMA). Ethidium bromide intercalation and gel retardation assays demonstrated high DNA condensation capacity of pHPMA-b-pDMAEMA. Nanoparticles prepared with and without decoy ODNs did not significantly compromise cellular safety at N/P ratios ⩽4. Transfection efficiency of pHPMA-b-pDMAEMA polyplexes (N/P=4) in Caco-2 cells was comparable to TurboFect transfection standard, resulting in a 98% reduction in P-gp protein levels. As a pharmacodynamic consequence, intracellular accumulation of the P-gp substrate Rhodamine123 significantly increased by almost twofold. In conclusion, NF-κB ODN polyplexes fabricated with pHPMA-b-pDMAEMA polymer effectively reduced P-gp-mediated efflux activity in Caco-2 cells, suggesting successful interference with NF-κB-binding sites in the promoter region of the ABCB1 gene.

  20. Elevation of glucosylceramide in multidrug-resistant cancer cells and accumulation in cytoplasmic droplets.

    PubMed

    Morjani, H; Aouali, N; Belhoussine, R; Veldman, R J; Levade, T; Manfait, M

    2001-10-15

    Multidrug-resistant (MDR) cancer cells have been shown to have an accumulation of glucosylceramide (GlcCer). In this study, we aim at localizing, at subcellular level, where these lipids accumulate. Neutral lipids and phospholipid containing organelles have been identified using confocal fluorescence microscopy and microspectrofluorometry by monitoring the emission of the fluorescent probe Nile-red. Data from confocal fluorescence microscopy analysis shows accumulation of neutral lipids in cytoplasmic droplets of MDR human carcinoma MCF7R cells. Microspectrofluorometric measurements show an increase of the gold-yellow emission intensity in MCF7R cells, corresponding to neutral lipids. Similar observations were made in human MDR vincristine-HL60 and doxorubicin-KB selected cells. Total cellular glucosylceramide (GlcCer) measurements using [(3)H]-palmitic acid and thin layer chromatography show a significant increase of GlcCer in MCF7R cells. Moreover, MCF7R cells treated with fluorescent GlcCer-bodipy exhibit an accumulation of this lipid in cytoplasmic droplets. Treatment of MCF7R cells with 1-phenyl-2-palmitoylamino-3-morpholino-1-propanolol (PPMP), a potent inhibitor of GlcCer synthase, attenuates the Nile-red fluorescence emission emanating from these structures and reverses MDR. Moreover, Golgi compartments stained with fluorescent PPMP-bodipy, show an increase in the Golgi compartments density. Treatment of MCF7R cells with cyclosporine A (CSA), tamoxifen (TMX) and 3'-azido-3'deoxythymidine (AZT) leads to the same effect observed in the presence of PPMP. Treatment of MCF7 and MCF7R with the beta-glucosidase inhibitor conduritol beta-epoxide (CBE) significantly increases resistance to daunorubicin only in MCF7R cells. These data demonstrate also that: (i) CSA, an inhibitor of MDR, has an additional target in addition to P-glycoprotein; and (ii) TMX (used in breast cancer treatment and prevention) and AZT (used in the treatment of HIV) could have side effects by

  1. The cellular uptake mechanism, intracellular transportation, and exocytosis of polyamidoamine dendrimers in multidrug-resistant breast cancer cells

    PubMed Central

    Zhang, Jie; Liu, Dan; Zhang, Mengjun; Sun, Yuqi; Zhang, Xiaojun; Guan, Guannan; Zhao, Xiuli; Qiao, Mingxi; Chen, Dawei; Hu, Haiyang

    2016-01-01

    Polyamidoamine dendrimers, which can deliver drugs and genetic materials to resistant cells, are attracting increased research attention, but their transportation behavior in resistant cells remains unclear. In this paper, we performed a systematic analysis of the cellular uptake, intracellular transportation, and efflux of PAMAM-NH2 dendrimers in multidrug-resistant breast cancer cells (MCF-7/ADR cells) using sensitive breast cancer cells (MCF-7 cells) as the control. We found that the uptake rate of PAMAM-NH2 was much lower and exocytosis of PAMAM-NH2 was much greater in MCF-7/ADR cells than in MCF-7 cells due to the elimination of PAMAM-NH2 from P-glycoprotein and the multidrug resistance-associated protein in MCF-7/ADR cells. Macropinocytosis played a more important role in its uptake in MCF-7/ADR cells than in MCF-7 cells. PAMAM-NH2 aggregated and became more degraded in the lysosomal vesicles of the MCF-7/ADR cells than in those of the MCF-7 cells. The endoplasmic reticulum and Golgi complex were found to participate in the exocytosis rather than endocytosis process of PAMAM-NH2 in both types of cells. Our findings clearly showed the intracellular transportation process of PAMAM-NH2 in MCF-7/ADR cells and provided a guide of using PAMAM-NH2 as a drug and gene vector in resistant cells. PMID:27536106

  2. The cellular uptake mechanism, intracellular transportation, and exocytosis of polyamidoamine dendrimers in multidrug-resistant breast cancer cells.

    PubMed

    Zhang, Jie; Liu, Dan; Zhang, Mengjun; Sun, Yuqi; Zhang, Xiaojun; Guan, Guannan; Zhao, Xiuli; Qiao, Mingxi; Chen, Dawei; Hu, Haiyang

    2016-01-01

    Polyamidoamine dendrimers, which can deliver drugs and genetic materials to resistant cells, are attracting increased research attention, but their transportation behavior in resistant cells remains unclear. In this paper, we performed a systematic analysis of the cellular uptake, intracellular transportation, and efflux of PAMAM-NH2 dendrimers in multidrug-resistant breast cancer cells (MCF-7/ADR cells) using sensitive breast cancer cells (MCF-7 cells) as the control. We found that the uptake rate of PAMAM-NH2 was much lower and exocytosis of PAMAM-NH2 was much greater in MCF-7/ADR cells than in MCF-7 cells due to the elimination of PAMAM-NH2 from P-glycoprotein and the multidrug resistance-associated protein in MCF-7/ADR cells. Macropinocytosis played a more important role in its uptake in MCF-7/ADR cells than in MCF-7 cells. PAMAM-NH2 aggregated and became more degraded in the lysosomal vesicles of the MCF-7/ADR cells than in those of the MCF-7 cells. The endoplasmic reticulum and Golgi complex were found to participate in the exocytosis rather than endocytosis process of PAMAM-NH2 in both types of cells. Our findings clearly showed the intracellular transportation process of PAMAM-NH2 in MCF-7/ADR cells and provided a guide of using PAMAM-NH2 as a drug and gene vector in resistant cells.

  3. Novel cellular determinants for reversal of multidrug resistance in cells expressing P170-glycoprotein.

    PubMed

    Yin, M B; Guo, B; Voigt, W; Vanhoefer, U; Gibbs, J F; Skenderis, B S; Frank, C; Wrzosek, C; Rustum, Y M

    1998-03-05

    fragmentation and specific cell-cycle perturbation are potentially important molecular determinants for reversal of multidrug resistance in addition to restoration of intracellular drug retention.

  4. miR-181b modulates multidrug resistance by targeting BCL2 in human cancer cell lines.

    PubMed

    Zhu, Wei; Shan, Xia; Wang, Tongshan; Shu, Yongqian; Liu, Ping

    2010-12-01

    MicroRNAs (miRNAs) are short noncoding RNA molecules, which posttranscriptionally regulate genes expression and play crucial roles in diverse biological processes, such as development, differentiation, apoptosis and proliferation. Here, we investigated the possible role of miRNAs in the development of multidrug resistance (MDR) in human gastric and lung cancer cell lines. We found that miR-181b was downregulated in both multidrug-resistant human gastric cancer cell line SGC7901/vincristine (VCR) and multidrug-resistant human lung cancer cell line A549/cisplatin (CDDP), and the downregulation of miR-181b in SGC7901/VCR and A549/CDDP cells was concurrent with the upregulation of BCL2 protein, compared with the parental SGC7901 and A549 cell lines, respectively. In vitro drug sensitivity assay demonstrated that overexpression of miR-181b sensitized SGC7901/VCR and A549/CDDP cells to anticancer drugs, respectively. The luciferase activity of a BCL2 3'-untranslated region-based reporter construct in SGC7901/VCR and A549/CDDP cells suggests that a new target site in the 3'UTR of BCL2 of the mature miR-181s (miR-181a, miR-181b, miR-181c and miR-181d) was found. Enforced miR-181b expression reduced BCL2 protein level and sensitized SGC7901/VCR and A549/CDDP cells to VCR-induced and CDDP-induced apoptosis, respectively. Taken together, our findings suggest that miR-181b could play a role in the development of MDR in both gastric and lung cancer cell lines, at least in part, by modulation of apoptosis via targeting BCL2.

  5. Multidrug-resistant hela cells overexpressing MRP1 exhibit sensitivity to cell killing by hyperthermia: Interactions with etoposide

    SciTech Connect

    Souslova, Tatiana; Averill-Bates, Diana A. . E-mail: averill.diana@uqam.ca

    2004-12-01

    Purpose: Multidrug resistance (MDR) remains one of the primary obstacles in cancer chemotherapy and often involves overexpression of drug efflux transporters such as P-glycoprotein and multidrug resistance protein 1 (MRP1). Regional hyperthermia is undergoing clinical investigation in combination with chemotherapy or radiotherapy. This study evaluates whether hyperthermia can reverse MDR mediated by MRP1 in human cervical adenocarcinoma (HeLa) cells. Methods and materials: Cytotoxicity of hyperthermia and/or etoposide was evaluated using sulforhodamine-B in HeLa cells overexpressing MRP1 and their drug-sensitive counterparts. Glutathione, glutathione peroxidase (GPx), and glutathione S-transferase (GST) were quantified by spectrophotometry. GST isoenzymes were quantified by immunodetection. Caspase activation was evaluated by fluorometry and chromatin condensation by fluorescence microscopy using Hoechst 33258. Necrosis was determined using propidium iodide. Results: The major finding is that HeLa and HeLaMRP cells are both sensitive to cytotoxicity of hyperthermia (41-45 deg C). Hyperthermia induced activation of caspase 3 and chromatin condensation. Although total levels of cell killing were similar, there was a switch from apoptotic to necrotic cell death in MDR cells. This could be explained by decreased glutathione and GPx in MDR cells. MDR cells also contained very low levels of GST and were resistant to etoposide-induced apoptosis. Hyperthermia caused a modest increase in etoposide-induced apoptosis in HeLa and HeLaMRP cells, which required appropriate heat-drug scheduling. Conclusions: Hyperthermia could be useful in eliminating MDR cells that overexpress MRP1.

  6. Multifunctional polyamidoamine-modified selenium nanoparticles dual-delivering siRNA and cisplatin to A549/DDP cells for reversal multidrug resistance.

    PubMed

    Zheng, Wenjing; Cao, Chengwen; Liu, Yanan; Yu, Qianqian; Zheng, Chuping; Sun, Dongdong; Ren, Xiaofan; Liu, Jie

    2015-01-01

    Multidrug resistance (MDR) is a major barrier against effective cancer treatment. Dual-delivering a therapeutic small interfering RNA (siRNA) and chemotherapeutic agents has been developed to reverse drug resistance in tumor cells. In this study, amine-terminated generation 5 polyamidoamine (PAMAM) dendrimers (G5.NH2)-modified selenium nanoparticles (G5@Se NP) were synthesized for the systemic dual-delivery of mdr1 siRNA and cisplatin (cis-diamminedichloroplatinum-(II), DDP), which was demonstrated to enhance siRNA loading, releasing efficiency and gene-silencing efficacy. When the mdr1 siRNA was conjugated with G5@Se NP via electrostatic interaction, a significant down-regulation of P-glycoprotein and multidrug resistance-associated protein expression was observed; G5@Se-DDP-siRNA arrested A549/DDP cells at G1 phase and led to enhanced cytotoxicity in A549/DDP cells through induction of apoptosis involving the AKT and ERK signaling pathways. Interestingly, G5@Se-DDP NP were much less reactive than DDP in the reactions with both MT and GSH, indicating that loading of DDP in a nano-delivery system could effectively prevent cell detoxification. Furthermore, animal studies demonstrated that the new delivery system of G5@Se-DDP-siRNA significantly enhanced the anti-tumor effect on tumor-bearing nude mice, with no appreciable abnormality in the major organs. These results suggest that G5@Se NP could be a potential platform to combine chemotherapy and gene therapy technology in the treatment of human disease.

  7. Sensitization to the cytotoxicity of melphalan by ethacrynic acid and hyperthermia in drug-sensitive and multidrug-resistant Chinese hamster ovary cells.

    PubMed

    Turcotte, S; Averill-Bates, D A

    2001-09-01

    The ability of physical and pharmacological modulators to increase the cytotoxicity of melphalan was investigated in Chinese hamster ovary cells using a clonogenic cell survival assay. Hyperthermia has potential for use in cancer treatment, particularly as an adjuvant to chemotherapy or radiotherapy. Ethacrynic acid is a glutathione S-transferase inhibitor and also undergoes conjugation with glutathione. Interactions between hyperthermia (41-43 degrees C), ethacrynic acid and melphalan were evaluated in multidrug-resistant (CH(R)C5) cells with overexpression of P-glycoprotein (33.69-fold), and in drug-sensitive (AuxB1) cells. GST alpha was expressed at a higher level (3.65-fold) in CH(R)C5 cells than in sensitive cells, whereas levels of isoforms pi and mu were the same. GST pi was the most highly expressed isoform in the two cell populations. Ethacrynic acid was cytotoxic at elevated temperatures, while it caused little or no cytotoxicity at 37 degrees C. This effect occurred in drug-resistant and drug-sensitive cells, and attributes thermosensitizing properties to ethacrynic acid. Ethacrynic acid (20 microM) alone did not alter the cytotoxicity of melphalan at 37 degrees C. Hyperthermia potentiated drug cytotoxicity in cells, both with and without ethacrynic acid treatment. Ethacrynic acid could be useful in cancer treatment by acting as a thermosensitizer when combined with heat and by enhancing the cytotoxicity of melphalan at elevated temperatures. A major advantage arising from the use of regional hyperthermia is the ability to target drug cytotoxicity to the tumor volume. A useful finding is that ethacrynic acid, heat and/or melphalan are also effective against multidrug-resistant cells with overexpression of P-glycoprotein.

  8. Sinomenine Sensitizes Multidrug-Resistant Colon Cancer Cells (Caco-2) to Doxorubicin by Downregulation of MDR-1 Expression

    PubMed Central

    Liu, Zhen; Duan, Zhi-Jun; Chang, Jiu-Yang; Zhang, Zhi-feng; Chu, Rui; Li, Yu-Ling; Dai, Ke-Hang; Mo, Guang-quan; Chang, Qing-Yong

    2014-01-01

    Chemoresistance in multidrug-resistant (MDR) cells over expressing P-glycoprotein (P-gp) encoded by the MDR1 gene, is a major obstacle to successful chemotherapy for colorectal cancer. Previous studies have indicated that sinomenine can enhance the absorption of various P-gp substrates. In the present study, we investigated the effect of sinomenine on the chemoresistance in colon cancer cells and explored the underlying mechanism. We developed multidrug-resistant Caco-2 (MDR-Caco-2) cells by exposure of Caco-2 cells to increasing concentrations of doxorubicin. We identified overexpression of COX-2 and MDR-1 genes as well as activation of the NF-κB signal pathway in MDR-Caco-2 cells. Importantly, we found that sinomenine enhances the sensitivity of MDR-Caco-2 cells towards doxorubicin by downregulating MDR-1 and COX-2 expression through inhibition of the NF-κB signaling pathway. These findings provide a new potential strategy for the reversal of P-gp-mediated anticancer drug resistance. PMID:24901713

  9. Retroviral transfer of a murine cDNA for multidrug resistance confers pleiotropic drug resistance to cells without prior drug selection

    SciTech Connect

    Guild, B.C.; Mulligan, R.C.; Gros, P.; Housman, D.E.

    1988-03-01

    The authors have constructed a retrovirus expression vector that carries the murine mdr cDNA transcribed under the control of the human H4 histone promoter to examine the feasibility of efficiently transferring a multidrug resistance phenotype to cells without requiring drug selection. This approach will facilitate the transfer of mdr cDNA to hematopoietic progenitor cells for the study of multidrug resistance in vivo. The retrovirus vector pHmdr has been used for transmission and expression of the mdr cDNA in initially drug-sensitive NIH 3T3 fibroblasts. Selection of pHmdr infectants in the cytotoxic agents colchicine or doxorubicin gave rise to highly multidrug-resistant colonies containing a single gene copy of the vector. Moreover, in the analysis of 12 cloned unselected NIH 3T3 cell infectants, a multidrug resistance phenotype was conferred by as few as two copies of the pHmdr vector. Overexpression of the mdr cDNA in drug-selected and unselected pHmdr infectants was directly related to cell survival in three cytotoxic agents tested. These results hold significant implications for the study of multidrug resistance in vivo.

  10. Terminal functionalized thiourea-containing dipeptides as multidrug-resistance reversers that target 20S proteasome and cell proliferation.

    PubMed

    Qin, Jian-Mei; Huang, Ri-Zhen; Yao, Gui-Yang; Liao, Zhi-Xin; Pan, Ying-Ming; Wang, Heng-Shan

    2017-01-27

    A series of inhibitors of 20S proteasome based on terminal functionalized dipeptide derivatives containing the thiourea moiety were synthesized and evaluated for inhibition of 20S proteasome and the effects of multidrug-resistance reversers. These compounds exhibited significant selectivity to the β5-subunit of the human 20S proteasome with IC50 values at submicromolar concentrations. A docking study of the most active compound 6i revealed key interactions between 6i and the active site of the 20S proteasome in which the thiourea moiety and a nitro group were important for improving activity. In particular, compound 6i appeared to be the most potent compound against the NCI-H460 cell line, and displayed similar efficiency in drug-sensitive versus drug-resistant cancer cell lines, at least partly, by inhibition of the activity of 20S proteasome and induce apoptosis. In addition, 6i-induced apoptosis was significantly facilitated in NCI-H460/DOX cells that had been pretreated with inhibitors of P-gp. Mechanistically, compound 6i might trigger apoptotic signalling pathway. Thus, we conclude that dipeptide derivatives containing the thiourea moiety may be the potential inhibitors of proteasome with the ability to reverse multidrug resistance.

  11. Dihydropyridines and multidrug resistance: previous attempts, present state, and future trends.

    PubMed

    Zarrin, Abdolhossein; Mehdipour, Ahmad R; Miri, Ramin

    2010-11-01

    Multidrug resistance is defined as the resistance of a tumor cell to the cytotoxic action of divergent drugs used in chemotherapy. Dihydropyridines are a class of calcium channel antagonists that were discovered to have a multidrug resistance reversing effect and prompted investigations resulting in the synthesis of hundreds of new derivatives. Most of the investigators tried to achieve two goals: a decrease in Ca²(+) channel-blocking activity and an increase in the multidrug resistance reversing effect. Most of the synthesized compounds failed in the later stages of studies especially in clinical trials because of pharmacokinetic or pharmacodynamic limitations. Therefore, it will be necessary to include new methods, such as combinatorial synthesis, and, more importantly, to apply computational methods based on global structure-activity relationship models that consider all problems. Moreover, some compounds should be synthesized that are effective on several multidrug resistance targets.

  12. Overcoming of P-glycoprotein-mediated multidrug resistance in K562/A02 cells using riccardin F and pakyonol, bisbibenzyl derivatives from liverworts.

    PubMed

    Ji, Mei; Shi, Yanquiu; Lou, Hongxiang

    2011-01-01

    Riccardin F and pakyonol, macrocyclic bisbibenzyls from Plagiochasm intermedium, have been confirmed to possess antifungic activities against Candida albicans. Herein, we evaluated their anti-tumor activity in vitro by employing K562 and K562/A02 cells, the well-known adriamycin (ADR)-induced multidrug resistance (MDR) tumor cell lines over-expressing P-glycoprotein (P-gp). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assays showed that riccardin F and pakyonol ranging from 0 to 6 μg/mL exhibited no inhibitory effects on the growth of the two cell lines. However, in the presence of 3 μg/mL riccardin F or pakyonol (non-cytotoxic concentration), the IC50 of ADR against K562/A02 cells decreased by 2.51- and 4.78-fold, respectively. Flow cytometry showed that riccardin F and pakyonol significantly enhanced the accumulation of ADR in K562/A02 cells. Furthermore, fluorescence intensity detection revealed that the two natural products remarkably increased the retention of rhodamine-123 in K562/A02 cells rather than in K562 cells, indicating that the major cause for riccardin F and pakyonol to reverse P-gp-mediated MDR in K562/A02 cells is probably due to the constrained transport activity of P-gp. This study explores the potential application of bisbibenzyl type compounds as modulators of P-gp-mediated MDR in tumor cells.

  13. The anthracycline resistance-associated (ara) gene, a novel gene associated with multidrug resistance in a human leukaemia cell line.

    PubMed Central

    Longhurst, T. J.; O'Neill, G. M.; Harvie, R. M.; Davey, R. A.

    1996-01-01

    Multidrug resistance (MDR) in cancer cells is a major contributor to the failure of chemotherapy treatment. This paper describes a novel protein named the anthracycline resistance associated (ARA) protein. The ara gene is amplified in the MDR leukaemia line CCRF-CEM/E1000 and its mRNA is overexpressed. ARA belongs to the ATP binding cassette (ABC) family of proteins. Another ABC protein, the multidrug resistance-associated protein (MRP), has previously been reported to be overexpressed in the CEM/E1000 subline. The primary amino acid sequence of ARA indicates that it is 49.5 kDa without glycosylation, and that it has one potential glycosylation site. ARA has one ATP binding site and associated transmembrane regions. This is in contrast to MRP (190 kDa, 172 kDa deglycosylated) and most other higher eukaryote ABC proteins, which consist of two similar halves, each having one ATP binding site. In addition to ARA being coexpressed with MRP, comparison of amino acid sequences showed that, among known proteins, ARA is most similar to the C-terminal half of MRP. Images Figure 1 Figure 2 PMID:8912525

  14. Modulation of mdr1 expression by cytokines in human colon carcinoma cells: an approach for reversal of multidrug resistance.

    PubMed Central

    Stein, U.; Walther, W.; Shoemaker, R. H.

    1996-01-01

    Reversal of multidrug resistance (MDR) may offer a means of increasing the effectiveness of tumour chemotherapy. A variety of recent evidence indicates that cytokines may be particularly useful in this endeavour. To investigate the molecular mechanism by which cytokines may sensitise multidrug-resistant colon carcinoma cells, HCT15 and HCT116, to treatment with MDR-related drugs, we evaluated the effects of the human cytokines tumour necrosis factor alpha (TNF alpha), interleukin 2 (IL-2) and interferon gamma (IFN gamma) on mdr1 gene expression at the mRNA level by reverse transcription-polymerase chain reaction (RT-PCR) and at the protein level with monoclonal antibodies by immuno flow cytometry. P-glycoprotein function was examined after accumulation of the fluorescent drug, doxorubicin, by flow cytometry. Chemosensitivity to doxorubicin and vincristine was analysed using the XTT assay. All three cytokines were found to modulate the MDR characteristics on mdr1 expression levels, P-glycoprotein function and measured chemosensitivity to MDR-associated anti-cancer drugs. This cytokine-induced reversal of MDR was strongly time dependent, with maximal effects after 48 and 72 h of cytokine treatment. If similar modulation of MDR phenotype can be obtained in in vivo models, it may be possible to verify the time course for modulation by cytokine treatment and to design appropriate clinical trials of this strategy for MDR reversal. Images Figure 1 PMID:8912533

  15. Saikosaponin A, an active glycoside from Radix bupleuri, reverses P-glycoprotein-mediated multidrug resistance in MCF-7/ADR cells and HepG2/ADM cells.

    PubMed

    Ye, Rui-Ping; Chen, Zhen-Dong

    2017-02-01

    1. The expression and function of P-glycoprotein (P-gp) is associated with the phenotype of multidrug resistance (MDR). Saikosaponin A (SSA) is a triterpenoid saponin isolated from Radix Bupleuri. This study was mainly designed to understand effects of SSA on MDR in MCF-7/ADR and HepG2/ADM cells. 2. MDR reversal was examined as the alteration of cytotoxic drugs IC50 in resistant cells in the presence of SSA by MTT assay, and was compared with the non-resistant cells. Apoptosis and uptake of P-gp substrates in the tumor cells were detected by flow cytometry. Western blot was performed to assay the expression of P-gp. 3. Our results demonstrate SSA could increase the chemosensitivity of P-gp overexpressing HepG2/ADM and MCF-7/ADR cells to doxorubicin (DOX), vincristine (VCR) and paclitaxel. SSA promoted apoptosis of MCF-7/ADR cells in the presence of DOX. Moreover, it could also increase the retention of P-gp substrates DOX and rhodamine 123 in MCF-7/ADR cells, and decrease digoxin efflux ratio in Caco-2 cell monolayer. Finally, a mechanistic study showed that SSA reduced P-gp expression without affecting hydrolytic activity of P-gp. 4. In conclusion, our findings suggest that SSA could be further developed for sensitizing resistant cancer cells and used as an adjuvant therapy together with anticancer drugs to improve their therapeutic efficacies.

  16. MiR-218 inhibits multidrug resistance (MDR) of gastric cancer cells by targeting Hedgehog/smoothened.

    PubMed

    Zhang, Xiang-Liang; Shi, Hui-Juan; Wang, Ji-Ping; Tang, Hong-Sheng; Cui, Shu-Zhong

    2015-01-01

    Multidrug resistance (MDR) is the main obstacle to successful chemotherapy for patients with gastric cancer. The microRNA miR-218 influences various pathobiological processes in gastric cancer, and its down-regulation in this disease raises the question of whether it normally inhibits MDR. In this study we observed that two MDR gastric cancer cell lines showed lower expression of miR-218 compared with their chemosensitive parental cell line. Overexpressing miR-218 chemosensitizes gastric cancer cells, slowed efflux of adriamycin, and accelerated drug-induced apoptosis. We identified the smoothened (SMO) gene as a functional target of miR-218, and found that SMO overexpression counteracts the chemosensitizing effects of miR-218. These findings suggest that miR-218 inhibits MDR of gastric cancer cells by down-regulating SMO expression.

  17. Multidrug resistance-1 in T lymphocytes and natural killer cells of adults with idiopathic thrombocytopenic purpura: effect of prednisone treatment.

    PubMed

    López-Karpovitch, Xavier; Graue, Gerardo; Crespo-Solís, Erick; Piedras, Josefa

    2008-07-01

    High P-glycoprotein-mediated multidrug resistance-1 (P-gp/MDR1) activity in lymphocytes from idiopathic thrombocytopenic purpura (ITP) patients may affect disease outcome. ITP treatment includes glucocorticoids that are substrates of P-gp; hence, P-gp functional activity and antigenic expression were assessed by flow cytometry in T and natural killer (NK) cells from ITP patients before and after prednisone therapy. Herein, patients' T and NK cells did not show increased MDR1 functional activity, whereas P-gp antigenic expression was significantly enhanced in both therapy-free and prednisone-treated patients. Prednisone treatment did not significantly modify the function and expression of MDR1 in T and NK cells of ITP patients.

  18. Role of XIAP in the malignant phenotype of transitional cell cancer (TCC) and therapeutic activity of XIAP antisense oligonucleotides against multidrug-resistant TCC in vitro.

    PubMed

    Bilim, Vladimir; Kasahara, Takashi; Hara, Noboru; Takahashi, Kota; Tomita, Yoshihiko

    2003-01-01

    XIAP directly inhibits executor caspases, making it the most downstream antiapoptotic molecule. Here, we examined the expression and function of XIAP in normal urothelium and TCC. We also examined the therapeutic effect of xiap AS PODN on the cell cycle and apoptosis of multidrug-resistant T24 bladder cancer cells. XIAP was moderately expressed in normal transitional epithelium with prominent expression on the superficial layer cells. Seventy-nine of 108 (73.15%) tumor samples were positive for XIAP protein, but XIAP positivity was not correlated with tumor stage or grade. Moreover, 4 bladder cancer cell lines (SCaBER, HT1376, T24 and RT4) expressed similar levels of XIAP. xiap AS PODN dose-dependently reduced the XIAP protein level and induced apoptosis, leading to decreased cell viability by 87%. Combined administration with doxorubicin resulted in marked cytotoxicity due to escalation of apoptosis. Overexpression of XIAP in T24 cells resulted in a modest but statistically significant (p < 0.01) survival advantage compared to parental cells. Thus, XIAP expression may be critical for maintaining the viability and drug resistance of TCC, and endogenous XIAP levels are sufficient to protect cells from apoptosis. Our results suggest that XIAP may play an important role early in human TCC carcinogenesis. xiap AS may be a candidate for use as a cancer therapy for overcoming drug resistance in highly malignant TCC.

  19. Multidrug-resistance gene (P-glycoprotein) is expressed by endothelial cells at blood-brain barrier sites

    SciTech Connect

    Cordon-Cardo, C.; O'Brien, J.P.; Casals, D.; Biedler, J.L.; Melamed, M.R.; Bertino, J.R. ); Rittman-Grauer, L. )

    1989-01-01

    Endothelial cells of human capillary blood vessels at the blood-brain and other blood-tissue barrier sites express P-glycoprotein as detected by mouse monoclonal antibodies against the human multidrug-resistance gene product. This pattern of endothelial cell expression may indicate a physiological role for P-glycoprotein in regulating the entry of certain molecules into the central nervous system and other anatomic compartments, such as the testes. These tissues, which limit the access of systemic drugs, are known pharmacologic sanctuaries for metastatic cancer. P-glycoprotein expression in capillary endothelium of brain and testes and not other tissues (i.e., kidney and placenta) may in part explain this phenomenon and could have important implications in cancer chemotherapy.

  20. Constitutive AhR activation leads to concomitant ABCG2-mediated multidrug resistance in cisplatin-resistant esophageal carcinoma cells.

    PubMed

    To, Kenneth K W; Yu, Le; Liu, Shuwen; Fu, Jianhua; Cho, Chi Hin

    2012-06-01

    Esophageal squamous cell carcinoma (ESCC) is a highly malignant disease that is generally not responding to chemotherapy. It is particularly predominant in China. Although ESCC is significantly associated with cigarette smoking, the relationship between its molecular pathogenesis and responsiveness to chemotherapy and cigarette smoke remains elusive. This study reported the constitutive activation of aryl hydrocarbon receptor (AhR), leading to ABCG2 upregulation and the multidrug resistance (MDR) phenotype, in ESCC cell lines with acquired cisplatin resistance. Reporter gene assay, chromatin immunoprecipitation analysis and specific gene knockdown confirmed that the enhanced AhR binding to a xenobiotic response element (XRE) within the ABCG2 promoter is responsible for ABCG2 overexpression. A HSP90 inhibitor (17-AAG) and two AhR antagonists (kaempferol and salicylamide) were shown to inhibit ABCG2 upregulation, thereby reversing the ABCG2-mediated MDR. Our data therefore advocate the use of these inhibitors as novel chemosensitizers for the treatment of esophageal cancer.

  1. 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.

  2. Multidrug resistance protein and topoisomerase 2 alpha expression in non-small cell lung cancer are related with brain metastasis postoperatively

    PubMed Central

    Huang, Huan; Liu, Jihong; Meng, Qinglian; Niu, Guozhong

    2015-01-01

    The aim of this study was to investigate association between expressions of multidrug resistance protein (MRP) and topoisomerase 2 alpha expression in non-small cell lung cancer (TOP2A) and brain metastasis operatively. The expression of MRP and TOP2A were performed using immunohistochemistry (IHC) staining, and the results were analyzed in correlation with clinicopathological data. A total of 286 NSCLC patients who underwent curative surgery between 2007 and 2013 were enrolled in this study. Positive expression of MRP and TOP2A were 62.2% and 37.8%. MRP positive expression in NSCLC was significantly correlated with tumor cell differentiation (P=0.028). TOP2A expression was significantly associated with patients’ smoking status, tumor histological type (P<0.05). The positive MRP group had significantly inferior survival rates for 2-year BMFS than did the negative MRP group (79.0% vs. 93.4%, P=0.003) by the Kaplan-Meier method and a log-rank test. Similarly, the positive TOP2A expression was inversely correlated with 2-year BMFS (84.2% vs. 93.4%, P=0.030). Multivariate analysis showed that gender, MRP expression and TOP2A expression were independent prognostic factors for BMFS (P<0.05). Positive expressions of MRP and TOP2A in the tumor tissue are associated with increased risk of developing brain metastases in NSCLC. PMID:26617887

  3. Screening for multidrug resistance in leukemia: cell reactivity to MRK-16 correlates with anthracycline retention and sensitivity of leukemic cells.

    PubMed

    Michieli, M; Damiani, D; Michelutti, A; Grimaz, S; Geromin, A; Fanin, R; Russo, D; Masolini, P; Baccarani, M

    1996-09-01

    The biologic and clinical importance of the multidrug resistance (MDR) that is related with the overexpression of the P170 glycoprotein (Pgp) is widely recognized. However, a major issue that has not yet been solved is the definition of the degree of Pgp expression which is associated with a significant decrease of the sensitivity of the cells to chemotherapy. For this reason we studied the leukemic cells from 83 cases of acute leukemia. Leukemic cells were fixed in PLP and treated with saponine. Pgp expression was assayed by flow cytometry, using the anti Pgp monoclonal antibody MRK-16. Results were expressed both as the number of positive cells and by the intensity of the reaction as defined by the mean fluorescence index (MFI), i.e. the ratio between the mean fluorescence intensity of the MRK-16 incubated cells and of the IgG2a incubated cells. Thus, Pgp expression was compared with the results of two in vitro tests of cell sensitivity to anthracyclines, daunorubicin (DNR) cell retention and DNR cytotoxicity. We found that it was not the number of MRK-16 positive cells, but the degree of the reaction with MRK-16 (MFI) that significantly related to the anthracycline toxicity tests. Therefore, we propose that for clinical purposes a quick and cheap determination of Pgp-related MDR in leukemic cells may be obtained by measuring the MFI with MRK-16 in a standard flow cytometry assay and that the assay may indeed be sufficient to estimate Pgp expression as well as the influence of Pgp on cell sensitivity to anthracyclines.

  4. Hepatocyte SLAMF3 reduced specifically the multidrugs resistance protein MRP-1 and increases HCC cells sensitization to anti-cancer drugs

    PubMed Central

    Eugenio, Mélanie Simoes; Demey, Baptiste; Singh, Amrathlal Rabbind; Ossart, Christèle; Bagami, Mohammed Al; Regimbeau, Jean-Marc; Nguyen-Khac, Eric; Naassila, Mickael

    2016-01-01

    Multidrug resistance MDR proteins (MRPs) are members of the C family of a group of proteins named ATP binding cassette (ABC) transporters. MRPs can transport drugs including anticancer drugs, nucleoside analogs, antimetabolites and tyrosine kinase inhibitors. Drugs used in HCC therapy, such as tyrosine kinase inhibitor sorafenib, are substrates of uptake and/or efflux transporters. Variable expression of MRPs at the plasma membrane of tumor cells may contribute to drug resistance and subsequent clinical response. Recently, we reported that the hepatocyte SLAMF3 expression (Signaling Lymphocytic Activation Molecule Family member 3) was reduced in tumor cells from hepatocellular carcinoma (HCC) compared to its high expression in adjacent tissues. In the present study, we make a strong correlation between induced SLAMF3 overexpression and the specific loss of MRP-1 expression and its functionalities as a drugs resistance transporter. No changes were observed on expression of ABCG2 and MDR. More importantly, we highlight a strong inverse correlation between MRP-1 and SLAMF3 expression in patients with HCC. We propose that the SLAMF3 overexpression in cancerous cells could represent a potential therapeutic strategy to improve the drugs sensibility of resistant cells and thus control the therapeutic failure in HCC patients. PMID:27081035

  5. Hepatocyte SLAMF3 reduced specifically the multidrugs resistance protein MRP-1 and increases HCC cells sensitization to anti-cancer drugs.

    PubMed

    Fouquet, Grégory; Debuysscher, Véronique; Ouled-Haddou, Hakim; Eugenio, Mélanie Simoes; Demey, Baptiste; Singh, Amrathlal Rabbind; Ossart, Christèle; Al Bagami, Mohammed; Regimbeau, Jean-Marc; Nguyen-Khac, Eric; Naassila, Mickael; Marcq, Ingrid; Bouhlal, Hicham

    2016-05-31

    Multidrug resistance MDR proteins (MRPs) are members of the C family of a group of proteins named ATP binding cassette (ABC) transporters. MRPs can transport drugs including anticancer drugs, nucleoside analogs, antimetabolites and tyrosine kinase inhibitors. Drugs used in HCC therapy, such as tyrosine kinase inhibitor sorafenib, are substrates of uptake and/or efflux transporters. Variable expression of MRPs at the plasma membrane of tumor cells may contribute to drug resistance and subsequent clinical response. Recently, we reported that the hepatocyte SLAMF3 expression (Signaling Lymphocytic Activation Molecule Family member 3) was reduced in tumor cells from hepatocellular carcinoma (HCC) compared to its high expression in adjacent tissues. In the present study, we make a strong correlation between induced SLAMF3 overexpression and the specific loss of MRP-1 expression and its functionalities as a drugs resistance transporter. No changes were observed on expression of ABCG2 and MDR. More importantly, we highlight a strong inverse correlation between MRP-1 and SLAMF3 expression in patients with HCC. We propose that the SLAMF3 overexpression in cancerous cells could represent a potential therapeutic strategy to improve the drugs sensibility of resistant cells and thus control the therapeutic failure in HCC patients.

  6. Multidrug Resistance-associated Protein-1 (MRP-1)-dependent Glutathione Disulfide (GSSG) Efflux as a Critical Survival Factor for Oxidant-enriched Tumorigenic Endothelial Cells.

    PubMed

    Gordillo, Gayle M; Biswas, Ayan; Khanna, Savita; Spieldenner, James M; Pan, Xueliang; Sen, Chandan K

    2016-05-06

    Endothelial cell tumors are the most common soft tissue tumors in infants. Tumor-forming endothelial (EOMA) cells are able to escape cell death fate despite excessive nuclear oxidant burden. Our previous work recognized perinuclear Nox-4 as a key contributor to EOMA growth. The objective of this work was to characterize the mechanisms by which EOMA cells evade oxidant toxicity and thrive. In EOMA cells, compared with in the cytosol, the nuclear GSSG/GSH ratio was 5-fold higher. Compared to the ratio observed in healthy murine aortic endothelial (MAE) cells, GSSG/GSH was over twice as high in EOMA cells. Multidrug resistance-associated protein-1 (MRP-1), an active GSSG efflux mechanism, showed 2-fold increased activity in EOMA compared with MAE cells. Hyperactive YB-1 and Ape/Ref-1 were responsible for high MRP-1 expression in EOMA. Proximity ligand assay demonstrated MRP-1 and YB-1 binding. Such binding enabled the nuclear targeting of MRP-1 in EOMA in a leptomycin-B-sensitive manner. MRP-1 inhibition as well as knockdown trapped nuclear GSSG, causing cell death of EOMA. Disulfide loading of cells by inhibition of GSSG reductase (bischoloronitrosourea) or thioredoxin reductase (auranofin) was effective in causing EOMA death as well. In sum, EOMA cells survive a heavy oxidant burden by rapid efflux of GSSG, which is lethal if trapped within the cell. A hyperactive MRP-1 system for GSSG efflux acts as a critical survival factor for these cells, making it a potential target for EOMA therapeutics.

  7. CD44-engineered mesoporous silica nanoparticles for overcoming multidrug resistance in breast cancer

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Liu, Ying; Wang, Shouju; Shi, Donghong; Zhou, Xianguang; Wang, Chunyan; Wu, Jiang; Zeng, Zhiyong; Li, Yanjun; Sun, Jing; Wang, Jiandong; Zhang, Longjiang; Teng, Zhaogang; Lu, Guangming

    2015-03-01

    Multidrug resistance is a major impediment for the successful chemotherapy in breast cancer. CD44 is over-expressed in multidrug resistant human breast cancer cells. CD44 monoclonal antibody exhibits anticancer potential by inhibiting proliferation and regulating P-glycoprotein-mediated drug efflux activity in multidrug resistant cells. Thereby, CD44 monoclonal antibody in combination with chemotherapeutic drug might be result in enhancing chemosensitivity and overcoming multidrug resistance. The purpose of this study is to investigate the effects of the CD44 monoclonal antibody functionalized mesoporous silica nanoparticles containing doxorubicin on human breast resistant cancer MCF-7 cells. The data showed that CD44-modified mesoporous silica nanoparticles increased cytotoxicity and enhanced the downregulation of P-glycoprotein in comparison to CD44 antibody. Moreover, CD44-engineered mesoporous silica nanoparticles provided active target, which promoted more cellular uptake of DOX in the resistant cells and more retention of DOX in tumor tissues than unengineered counterpart. Animal studies of the resistant breast cancer xenografts demonstrated that CD44-engineered drug delivery system remarkably induced apoptosis and inhibited the tumor growth. Our results indicated that the CD44-engineered mesoporous silica nanoparticle-based drug delivery system offers an effective approach to overcome multidrug resistance in human breast cancer.

  8. A comparison of membrane properties and composition between cell lines selected and transfected for multi-drug resistance.

    PubMed Central

    Callaghan, R.; van Gorkom, L. C.; Epand, R. M.

    1992-01-01

    Cell lines selected (CHRC5) and transfected (LR-73-1A) for multi-drug resistance have total lipid compositions which are indistinguishable between resistant and parental cells. Lipid composition was evaluated by 1H NMR and the total fatty acid content by GLC. No change in surface hydrophobicity, as measured with the fluorescent probe dansyl-PE, was observed as a result of transfection of CHO cells with the mdr1 gene. However, the selected cell line, CHRC5, showed a decreased surface hydrophobicity. This decreased surface hydrophobicity was indicated by an 8 nm increase in the fluorescence emission of dansyl-PE in the CHRC5 cell line compared with the AB1. Both resistant cell lines showed an increase in the polarisation of the fluorescent probe, TMA-DPH in the plasma membranes corresponding to a 14% and a 24% change in fluorescence polarisation for the selected and transfected cell lines, respectively. This is indicative of reduced mobility of the acyl chains in the resistant cell lines. Both the CHRC5 and the transfected cell lines showed almost a 2-fold increase in the initial rate of membrane cycling. The membrane cycling could be inhibited by a known bilayer stabiliser, the N-carbobenzoxy-D-Phe-L-Phe-Gly. These results indicate that the properties of the plasma membrane from resistant cells are altered compared with their parental cell line. PMID:1358166

  9. Isomahanine induces endoplasmic reticulum stress and simultaneously triggers p38 MAPK-mediated apoptosis and autophagy in multidrug-resistant human oral squamous cell carcinoma cells.

    PubMed

    Utaipan, Tanyarath; Athipornchai, Anan; Suksamrarn, Apichart; Chunsrivirot, Surasak; Chunglok, Warangkana

    2017-02-01

    Advanced oral squamous cell carcinoma (OSCC) is typically aggressive and closely correlated with disease recurrence and poor survival. Multidrug resistance (MDR) is the most critical problem leading to therapeutic failure. Investigation of novel anticancer candidates targeting multidrug-resistant OSCC cells may provide a basis for developing effective strategies for OSCC treatment. In the present study, we investigated the cytotoxic mechanism of a carbazole alkaloid, namely isomahanine, in a multidrug‑resistant OSCC cell line CLS-354/DX. We demonstrated that CLS-354/DX cells overexpressing multidrug resistance-associated protein 1 (MRP1) were resistant to anticancer drugs cisplatin and camptothecin. Isomahanine effectively induced cytotoxicity against CLS-354/DX cells regardless of resistance. Apoptosis as determined by FITC‑Annexin V/PI staining and western blot analysis of cleaved caspase-3 and cleaved poly(ADP‑ribose) polymerase (PARP) was significantly induced in a time-dependent manner upon isomahanine treatment. Isomahanine-induced caspase‑dependent apoptosis was determined using z-VAD‑fmk. The effects on autophagy in isomahanine-treated cells were investigated via conversion of LC3B and degradation of p62/SQSTM1 (p62). Isomahanine obviously induced autophagic flux as shown by an increase in punctate GFP-LC3B and the LC3B-II/LC3B-I ratio with a concomitant decrease in p62 levels. Autophagy inhibitors 3-methyladenine (3-MA) and chloroquine (CQ) protected isomahanine-induced cell death, indicating the activation of autophagic cell death. Endoplasmic reticulum (ER) stress and MAPK activation were examined to elucidate the mechanism underlying cell death. The expression levels of PERK, CHOP and phosphorylated MAPK (p38, ERK1/2 and JNK1/2) were upregulated following isomahanine treatment. We found that p38 MAPK inhibitor (SB203580) significantly attenuated isomahanine-induced apoptosis and autophagic flux and this prevented cell death. Collectively

  10. Pseudolaric acid B circumvents multidrug resistance phenotype in human gastric cancer SGC7901/ADR cells by downregulating Cox-2 and P-gp expression.

    PubMed

    Yu, Fei; Li, Kai; Chen, Suning; Liu, Yunpeng; Li, Yan

    2015-01-01

    Multidrug resistance (MDR) is a challenging issue in the treatment of gastric cancer. Pseudolaric acid B is a new diterpene acid compound isolated from pseudolarix, which has been found to have anti-tumor activities in recent studies. The purpose of the present study was to evaluate the effects of pseudolaric acid B in an MDR gastric cancer cell line and elucidate the possible underlying mechanisms of action. SGC7901/ADR, a P-glycoprotein (P-gp)-overexpressing cell line, was used to evaluate the efficacy of pseudolaric acid B against MDR phenotypes. The effects of pseudolaric acid B and chemotherapeutic agents on cell proliferation and apoptosis were assessed using the MTT assay and flow cytometry, respectively. Immunocytochemistry and Western blot were used to detect the possible relevant molecules in order to elucidate the underlying mechanism of action. The results showed that pseudolaric acid B inhibited cell proliferation and induced apoptosis in SGC7901/ADR cells. A low dose of pseudolaric acid B (0.5 µmol/L) augmented the inhibitory effects of chemotherapeutic agents on proliferation (p < 0.05). The expression of P-gp and cyclooxygenase 2 (Cox-2) was downregulated with pseudolaric acid B treatment. The present results showed that pseudolaric acid B inhibited cell proliferation, induced apoptosis, circumvented MDR, and increased the sensitivity of chemotherapeutic agents in vitro by downregulating the expression of P-gp and Cox-2.

  11. EZH2 inhibition re-sensitizes multidrug resistant B-cell lymphomas to etoposide mediated apoptosis

    PubMed Central

    Smonskey, Matthew; Lasorsa, Elena; Rosario, Spencer; Kirk, Jason S.; Hernandez-Ilizaliturri, Francisco J.; Ellis, Leigh

    2016-01-01

    Reactivation of apoptotic pathways is an attractive strategy for patients with treatment-resistant B-cell lymphoma. The tumor suppressor, p53 is central for apoptotic response to multiple DNA damaging agents used to treat aggressive B-cell lymphomas, including etoposide. It has been demonstrated that etoposide induced DNA damage and therapeutic efficacy is enhanced by combination with inhibitors of the histone methyltransferase, enhancer of zeste homolog 2 (EZH2). Further, EZH2 was identified to regulate cell fate decisions in response to DNA damage. Using B-cell lymphoma cell lines resistant to etoposide induced cell death; we show that p53 is dramatically down regulated and MDMX, a negative regulator of p53, is significantly up regulated. However, these cell lines remain responsive to etoposide mediated DNA damage and exhibit cell cycle inhibition and induction of senescence. Furthermore, chemical inhibition of EZH2 directs DNA damage to a predominant p53 dependent apoptotic response associated with loss of MDMX and BCL-XL. These data provide confirmation of EZH2 in determining cell fate following DNA damage and propose a novel therapeutic strategy for patients with aggressive treatment-resistant B-cell lymphoma. PMID:26973857

  12. Differential levels of human leukocyte antigen-class I, multidrug-resistance 1 and androgen receptor expressions in untreated prostate cancer cells: the robustness of prostate cancer.

    PubMed

    Homma, Shigenori; Komohara, Yoshihiro; Harada, Mamoru; Saya, Hideyuki; Todo, Satoru; Itoh, Kyogo; Noguchi, Masanori

    2007-08-01

    Tumors are highly robust and maintain their proliferative potential against a wide range of both host-defense mechanisms and anticancer therapies. One of the approaches to overcome cancer robustness could be combined therapy in which each modality imposes independent selective pressures against the acquired mutation of cancer. To develop such a therapy, it is crucial to understand the magnitude of acquired mutations. In this study, we investigated the levels of human leukocyte antigen (HLA)-class I, multidrug-resistance 1 (MDR1), and androgen receptor (AR) expressions in untreated prostate cancers harvested by radical prostatectomy. The mean percentages of cancer cells expressing HLA-class I, MDR and AR among the 10 cancer samples were 41, 35 and 74%, respectively. In addition, double-staining of HLA and MDR revealed the four definite populations (HLA+/MDR+, HLA+/MDR-, HLA-/MDR+ and HLA-/MDR-) in cancer tissues from the majority of cancer patients tested, and the mean percentages of cells expressing these combinations were 13, 29, 22 and 38%, respectively. Similar results were obtained by double-staining of HLA and AR, except for 2 cases in which HLA-/AR+ cancer cells predominated. These results indicated that untreated prostate cancer cells acquired a wide range of genomic mutations, which may have been caused by internal host pressure to eliminate malignant cells, and would provide evidence of the robustness of untreated prostate cancer.

  13. CacyBP/SIP enhances multidrug resistance of pancreatic cancer cells by regulation of P-gp and Bcl-2.

    PubMed

    Chen, Xiong; Zheng, Peichan; Xue, Zengfu; Li, Jie; Wang, Wenwu; Chen, Xi; Xie, Fangwei; Yu, Zongyang; Ouyang, Xuenong

    2013-07-01

    Our former report indicates that calcyclin-binding protein or Siah-1-interacting protein (CacyBP/SIP) is over-expressed in the SGC7901/ADR cell line. However, the potential role of CacyBP/SIP in the development of multidrug resistance (MDR) of pancreatic cancer is still uncertain. In this paper, we investigated the role of CacyBP/SIP in MDR of pancreatic cancer cells and its possible underlying mechanisms, and found that CacyBP/SIP was over-expressed in the Gemcitabine induced MDR pancreatic cancer cell PC-3/Gem compared with its parental cell PC-3. Up-regulation of CacyBP/SIP expression could enhance resistance of chemotherapy drugs on PC-3 cells and inhibit Adriamycin-induced apoptosis accompanied by decreased accumulation of intracellular Adriamycin. Furthermore, CacyBP/SIP could significantly up-regulate the expression of P-gp, Bcl-2, and the transcription of the MDR1 gene. In addition, the decrease of CacyBP/SIP expression using RNA interference or P-gp inhibitor could partially reverse CacyBP/SIP-mediated MDR. In brief, our study demonstrated that CacyBP/SIP could enhance the MDR phenotype of pancreatic cancer cells by increasing the expression of P-gp and Bcl-2, thus inhibiting apoptosis of pancreatic cancer cell.

  14. Biodegradable cationic polymeric nanocapsules for overcoming multidrug resistance and enabling drug-gene co-delivery to cancer cells

    NASA Astrophysics Data System (ADS)

    Chen, Chih-Kuang; Law, Wing-Cheung; Aalinkeel, Ravikumar; Yu, Yun; Nair, Bindukumar; Wu, Jincheng; Mahajan, Supriya; Reynolds, Jessica L.; Li, Yukun; Lai, Cheng Kee; Tzanakakis, Emmanuel S.; Schwartz, Stanley A.; Prasad, Paras N.; Cheng, Chong

    2014-01-01

    Having unique architectural features, cationic polymeric nanocapsules (NCs) with well-defined covalently stabilized biodegradable structures were generated as potentially universal and safe therapeutic nanocarriers. These NCs were synthesized from allyl-functionalized cationic polylactide (CPLA) by highly efficient UV-induced thiol-ene interfacial cross-linking in transparent miniemulsions. With tunable nanoscopic sizes, negligible cytotoxicity and remarkable degradability, they are able to encapsulate doxorubicin (Dox) with inner cavities and bind interleukin-8 (IL-8) small interfering RNA (siRNA) with cationic shells. The Dox-encapsulated NCs can effectively bypass the P-glycoprotein (Pgp)-mediated multidrug resistance of MCF7/ADR cancer cells, thereby resulting in increased intracellular drug concentration and reduced cell viability. In vitro studies also showed that the NCs loaded with Dox, IL-8 siRNA and both agents can be readily taken up by PC3 prostate cancer cells, resulting in a significant chemotherapeutic effect and/or IL-8 gene silencing.Having unique architectural features, cationic polymeric nanocapsules (NCs) with well-defined covalently stabilized biodegradable structures were generated as potentially universal and safe therapeutic nanocarriers. These NCs were synthesized from allyl-functionalized cationic polylactide (CPLA) by highly efficient UV-induced thiol-ene interfacial cross-linking in transparent miniemulsions. With tunable nanoscopic sizes, negligible cytotoxicity and remarkable degradability, they are able to encapsulate doxorubicin (Dox) with inner cavities and bind interleukin-8 (IL-8) small interfering RNA (siRNA) with cationic shells. The Dox-encapsulated NCs can effectively bypass the P-glycoprotein (Pgp)-mediated multidrug resistance of MCF7/ADR cancer cells, thereby resulting in increased intracellular drug concentration and reduced cell viability. In vitro studies also showed that the NCs loaded with Dox, IL-8 siRNA and both

  15. Upregulating miR-146a by physcion reverses multidrug resistance in human chronic myelogenous leukemia K562/ADM cells

    PubMed Central

    Liu, Wenjun; He, Juan; Yang, Yiling; Guo, Qulian; Gao, Fei

    2016-01-01

    The aim of this study was to evaluate the role of miR-146a in the drug resistance of chronic myelogenous leukemia (CML) cells (K562/ADM) and to investigate the reversal effect of physcion, a natural compound, on the multidrug-resistance in CML. Our results showed that miR-146a was significantly downregulated in drug-resistant K562 cells and the overexpression of miR-146a in K562/ADM cells could restore the sensitivity to adriamycin (ADM). In addition, our results showed that the downregulation of miR-146a was associated with increase in CXCR4 expression, which was a direct target of miR-146a. Moreover, our findings also provided experimental evidence that physcion could enhance the anti-proliferative effect of ADM in K562/ADM cells by upregulating miR-146a. In conclusion, this present study showed that miR-146a conferred ADM resistance in CML cells and physcion could improve the sensitivity of K562/ADM cells by enhancing apoptosis via upregulating miR-146a. PMID:27904770

  16. New mouse xenograft model modulated by tumor-associated fibroblasts for human multi-drug resistance in cancer

    PubMed Central

    MA, YAN; LIN, ZHIQIANG; FALLON, JOHN K.; ZHAO, QIANG; LIU, DAN; WANG, YONGJUN; LIU, FENG

    2015-01-01

    We developed an MDR tumor model that is modulated by tumor-associated fibroblasts. Studies on proliferation of tumor cell lines including paclitaxel-sensitive and resistant cell lines were performed. The expressions of P-gp and α-smooth muscle actin (α-SMA) antigen were evaluated by immunohistochemistry and western blot analysis. Quantitative P-gp analyses of different cell lines were accomplished by nanoUPLC-MS/MS. Tumor cell colony formation assay and established xenograft model was used to investigate the relationship between P-gp expression, fibroblast levels and tumorigenesis. The mouse xenograft model was developed after co-inoculation with MDR tumor cells and NIH/3T3 fibroblast cells. There was no correlation between tumorigenesis in vivo and the growth rate of cells in vitro. The proliferation among different cell lines had no significant differences, but the P-gp expression and tumor growth in the xenograft model were fairly different. P-gp determination and α-SMA immunofluorescence staining clarified the relationship between P-gp expression, fibroblast levels and tumorigenesis. It was more difficult for tumor cells with higher P-gp levels to recruit fibroblasts in vivo, resulting in lower tumorigenesis due to the lack of structural and chemical support during tumor progression. In the established paclitaxel-resistant mouse xenograft model, no obvious antitumor effect was observed after Taxol treatment, but a significant decrease in tumor size for the group treated with gemcitabine sensitive to the model. The results show that the added fibroblasts do not disturb the applicability of the model in MDR. Therefore, this mouse xenograft MDR model could serve as an effective tool for MDR research. PMID:26352907

  17. Multidrug resistance in chronic myeloid leukaemia: how much can we learn from MDR–CML cell lines?

    PubMed Central

    Rumjanek, Vivian M.; Vidal, Raphael S.; Maia, Raquel C.

    2013-01-01

    The hallmark of CML (chronic myeloid leukaemia) is the BCR (breakpoint cluster region)–ABL fusion gene. CML evolves through three phases, based on both clinical and pathological features: a chronic phase, an accelerated phase and blast crisis. TKI (tyrosine kinase inhibitors) are the treatment modality for patients with chronic phase CML. The therapeutic potential of the TKI imatinib is affected by BCR–ABL dependent an independent mechanisms. Development of MDR (multidrug resistance) contributes to the overall clinical resistance. MDR involves overexpression of ABC -transporters (ATP-binding-cassette transporter) among other features. MDR studies include the analysis of cancer cell lines selected for resistance. CML blast crisis is accompanied by increased resistance to apoptosis. This work reviews the role played by the influx transporter OCT1 (organic cation transporter 1), by efflux ABC transporters, molecules involved in the modulation of apoptosis (p53, Bcl-2 family, CD95, IAPs (inhibitors of apoptosis protein)], Hh and Wnt/β-catenin pathways, cytoskeleton abnormalities and other features described in leukaemic cells of clinical samples and CML cell lines. An MDR cell line, Lucena-1, generated from K562 by stepwise exposure to vincristine, was used as our model and some potential anticancer drugs effective against the MDR cell line and patients’ samples are presented. PMID:24070327

  18. Overexpression of the cystic fibrosis transmembrane conductance regulator in NIH 3T3 cells lowers membrane potential and intracellular pH and confers a multidrug resistance phenotype.

    PubMed Central

    Wei, L Y; Stutts, M J; Hoffman, M M; Roepe, P D

    1995-01-01

    Because of the similarities between the cystic fibrosis transmembrane conductance regulator (CFTR) and multidrug resistance (MDR) proteins, recent observations of decreased plasma membrane electrical potential (delta psi) in cells overexpressing either MDR protein or the CFTR, and the effects of delta psi on passive diffusion of chemotherapeutic drugs, we have analyzed chemotherapeutic drug resistance for NIH 3T3 cells overexpressing different levels of functional CFTR. Three separate clones not previously exposed to chemotherapeutic drugs exhibit resistance to doxorubicin, vincristine, and colchicine that is similar to MDR transfectants not previously exposed to chemotherapeutic drugs. Two other clones expressing lower levels of CFTR are less resistant. As shown previously these clones exhibit decreased plasma membrane delta psi similar to MDR transfectants, but four of five exhibit mildly acidified intracellular pH in contrast to MDR transfectants, which are in general alkaline. Thus the MDR protein and CFTR-mediated MDR phenotypes are distinctly different. Selection of two separate CFTR clones on either doxorubicin or vincristine substantially increases the observed MDR and leads to increased CFTR (but not measurable MDR or MRP) mRNA expression. CFTR overexpressors also exhibit a decreased rate of 3H -vinblastine uptake. These data reveal a new and previously unrecognized consequence of CFTR expression, and are consistent with the hypothesis that membrane depolarization is an important determinant of tumor cell MDR. Images FIGURE 1 FIGURE 3 FIGURE 6 PMID:8519988

  19. Reversal of multidrug resistance in human lung cancer cells by delivery of 3-octadecylcarbamoylacrylic acid–cisplatin-based liposomes

    PubMed Central

    Song, Juan; Ren, Weifang; Xu, Tingting; Zhang, Yi; Guo, Hongyu; Zhu, Shanshan; Yang, Li

    2017-01-01

    Liposome-based drug delivery system would be an innovative and promising candidate to circumvent multidrug resistance (MDR) of cisplatin (CDDP). However, the reversal efficacy of liposomal CDDP was severely impaired by weak cellular uptake and insufficient intracellular drug release. In this study, 3-octadecylcarbamoylacrylic acid–CDDP nanocomplex (OMI–CDDP–N)-based liposomes (OCP-L) with high cellular uptake and sufficient intracellular drug release were designed to circumvent MDR of lung cancer. OMI–CDDP–N was synthesized through a pH-sensitive monocarboxylato and an O→Pt coordinate bond, which is more efficient than CDDP. Also, OCP-L incorporated with OMI–CDDP–N could induce effective cellular uptake, enhanced nuclear distribution, and optimal cellular uptake kinetics. In particular, OCP-L presented superior effects on enhancing cell apoptosis and in vitro cytotoxicity in CDDP-resistant human lung cancer (A549/CDDP) cells. The mechanisms of MDR reversal in A549/CDDP cells by OCP-L could attribute to organic cation transporter 2 restoration, ATPase copper-transporting beta polypeptide suppression, hypoxia-inducible factor 1 α-subunit depletion, and phosphatidylinositol 3-kinase/Akt pathway inhibition. These results demonstrated that OCP-L may provide an effective delivery of CDDP to resistant cells to circumvent MDR and enhance the therapeutic index of the chemotherapy. PMID:28255230

  20. The uptake of hydroxypropyl methacrylamide based homo, random and block copolymers by human multi-drug resistant breast adenocarcinoma cells

    PubMed Central

    Barz, Matthias; Luxenhofer, Robert; Zentel, Rudolf; Kabanov, Alexander V.

    2011-01-01

    A series of well defined, fluorescently labelled homopolymers, random and block copolymers based on N-(2-hydroxypropyl)-methacrylamide was prepared by reversible addition-fragmentation chain transfer polymerization (RAFT-polymerization). The polydispersity indexes for all polymers were in the range of 1.2 to 1.3 and the number average of the molar mass (Mn) for each polymer was set to be in the range of 15 kDa to 30 kDa. The cellular uptake of these polymers was investigated in the human multi-drug resistant breast adenocarcinoma cell line MCF7/ADR. The uptake greatly depended on the polymer molecular mass and structure. Specifically, smaller polymers (approx. 15 kDa) were taken up by the cells at much lower concentrations than larger polymers (approx. 30 kDa). Furthermore, for polymers of the same molar mass, the random copolymers were more easily internalized in cells than block copolymers or homopolymers. This is attributed to the fact that random copolymers form micelle-like aggregates by intra- and interchain interactions, which are smaller and less stable than the block copolymer structures in which the hydrophobic domain is buried and thus prevented from unspecific interaction with the cell membrane. Our findings underline the need for highly defined polymeric carriers and excipients for future applications in the field of nanomedicine. PMID:19631373

  1. Visual detection of multidrug resistance gene in living cell using the molecular beacon imaging

    NASA Astrophysics Data System (ADS)

    Zhou, Qiumei; Ma, Yi; Gu, Yueqing

    2014-09-01

    A major problem in cancer treatment is the development of resistance to chemotherapeutic agents in tumor cells. Detection of effective prognostic biomarkers and targets are of crucial importance to the management of individualized therapies. However, quantitative analysis of the drug resistance gene had been difficult because of technical limitations. In this study, we designed and used a special hairpin deoxyribonucleic acid (DNA), which served as a beacon for detecting human drug resistance indicater. Upon hybridizing with the target mRNA, the hairpin DNA modified gold nanoparticle beacons (hDAuNP beacons) release the fluorophores attached at 5'end of the oligonucleotide sequence. The fluorescence properties of the beacon before and after the hybridization with the complementary DNA were confirmed in vitro. The hDAuNP beacons could be taken up by living cells with low inherent cytotoxicity and higher stability. hDAuNP beacon imaged by confocal laser scanning microscopy to detect the resistance gene expression. The detected fluorescence in MCF7and MCF7/ADR cells correlates with the specific drug resistance gene expression, which is consistent with the result from Q-PCR. Thus, this approach overcame many of the challenges of previous techniques by creating highly sensitive and effective intracellular probes for monitoring gene expression.

  2. In vitro antileukaemic activity of extracts from chokeberry (Aronia melanocarpa [Michx] Elliott) and mulberry (Morus alba L.) leaves against sensitive and multidrug resistant HL60 cells.

    PubMed

    Skupień, Katarzyna; Kostrzewa-Nowak, Dorota; Oszmiański, Jan; Tarasiuk, Jolanta

    2008-05-01

    The aim of the present study was to determine in vitro antileukaemic activities of extracts obtained from chokeberry (Aronia melanocarpa [Michx] Elliot) and mulberry (Morus alba L.) leaves against promyelocytic HL60 cell line and its multidrug resistant sublines exhibiting two different MDR phenotypes: HL60/VINC (overexpressing P-glycoprotein) and HL60/DOX (overexpressing MRP1 protein). It was found that the extracts from chokeberry and mulberry leaves were active against the sensitive leukaemic cell line HL60 and retained the in vitro activity against multidrug resistant sublines (HL60/VINC and HL60/DOX). The values of resistance factor (RF) found for these extracts were very low lying in the range 1.2-1.6.

  3. B4GALT family mediates the multidrug resistance of human leukemia cells by regulating the hedgehog pathway and the expression of p-glycoprotein and multidrug resistance-associated protein 1

    PubMed Central

    Zhou, H; Ma, H; Wei, W; Ji, D; Song, X; Sun, J; Zhang, J; Jia, L

    2013-01-01

    β-1, 4-Galactosyltransferase gene (B4GALT) family consists of seven members, which encode corresponding enzymes known as type II membrane-bound glycoproteins. These enzymes catalyze the biosynthesis of different glycoconjugates and saccharide structures, and have been recognized to be involved in various diseases. In this study, we sought to determine the expressional profiles of B4GALT family in four pairs of parental and chemoresistant human leukemia cell lines and in bone marrow mononuclear cells (BMMC) of leukemia patients with multidrug resistance (MDR). The results revealed that B4GALT1 and B4GALT5 were highly expressed in four MDR cells and patients, altered levels of B4GALT1 and B4GALT5 were responsible for changed drug-resistant phenotype of HL60 and HL60/adriamycin-resistant cells. Further data showed that manipulation of these two gene expression led to increased or decreased activity of hedgehog (Hh) signaling and proportionally mutative expression of p-glycoprotein (P-gp) and MDR-associated protein 1 (MRP1) that are both known to be related to MDR. Thus, we propose that B4GALT1 and B4GALT5, two members of B4GALT gene family, are involved in the development of MDR of human leukemia cells, probably by regulating the activity of Hh signaling and the expression of P-gp and MRP1. PMID:23744354

  4. Cytotoxic effect of the cyclosporin PSC 833 in multidrug-resistant leukaemia cells with increased expression of P-glycoprotein.

    PubMed Central

    Lehne, G.; Rugstad, H. E.

    1998-01-01

    Multidrug resistance (MDR) to anti-cancer agents is frequently associated with overexpression of the drug efflux transporter P-glycoprotein (Pgp) in cancer cells, ensuing drug expulsion and maintenance of tolerable intracellular levels of certain cytotoxic drugs. Pgp may also be present in normal tissue, providing protection against toxic substances, but the physiological role of Pgp is not fully understood. Recently, it was shown that Pgp also takes part in the transport of certain growth-regulating cytokines (Drach et al, 1996; Raghu et al, 1996). Therefore, we studied the effect of the highly potent Pgp inhibitor PSC 833 on proliferation of three pairs of MDR and parental human cell lines (HB8065 hepatoma cells, KG1a and K562 leukaemia cells). The MDR phenotypes were characterized by Pgp overexpression, which was demonstrated by flow cytometry using the anti-Pgp antibody MRK16. Electronic cell counting of 72-96 h cultures revealed a dose-dependent antiproliferative effect of PSC 833 in the resistant KG1a/200 and K562/150 cells. The half-maximal growth inhibitory concentrations (GI50) were 0.2 microM and 0.7 microM respectively. Exposure to PSC 833 induced cell death by apoptosis in both cell types, as revealed by flow cytometry and detection of 3'-hydroxy ends of DNA (the result of DNA fragmentation associated with apoptosis), by terminal transferase-mediated dUTP-biotin nick end-labelling (TUNEL). Similar effects were not found in the hepatoma cell lines or the parental leukaemia lines. These results demonstrated a discriminating cytotoxicity of PSC 833 in two human leukaemia MDR variants, representing a possible therapeutic indication which warrants consideration during the ongoing clinical evaluation of this drug. Images Figure 8 PMID:9744497

  5. Glutathione and multidrug resistance protein transporter mediate a self-propelled disposal of bismuth in human cells.

    PubMed

    Hong, Yifan; Lai, Yau-Tsz; Chan, Godfrey Chi-Fung; Sun, Hongzhe

    2015-03-17

    Glutathione and multidrug resistance protein (MRP) play an important role on the metabolism of a variety of drugs. Bismuth drugs have been used to treat gastrointestinal disorder and Helicobacter pylori infection for decades without exerting acute toxicity. They were found to interact with a wide variety of biomolecules, but the major metabolic pathway remains unknown. For the first time (to our knowledge), we systematically and quantitatively studied the metabolism of bismuth in human cells. Our data demonstrated that over 90% of bismuth was passively absorbed, conjugated to glutathione, and transported into vesicles by MRP transporter. Mathematical modeling of the system reveals an interesting phenomenon. Passively absorbed bismuth consumes intracellular glutathione, which therefore activates de novo biosynthesis of glutathione. Reciprocally, sequestration by glutathione facilitates the passive uptake of bismuth and thus completes a self-sustaining positive feedback circle. This mechanism robustly removes bismuth from both intra- and extracellular space, protecting critical systems of human body from acute toxicity. It elucidates the selectivity of bismuth drugs between human and pathogens that lack of glutathione, such as Helicobacter pylori, opening new horizons for further drug development.

  6. Glutathione and multidrug resistance protein transporter mediate a self-propelled disposal of bismuth in human cells

    PubMed Central

    Hong, Yifan; Lai, Yau-Tsz; Chan, Godfrey Chi-Fung; Sun, Hongzhe

    2015-01-01

    Glutathione and multidrug resistance protein (MRP) play an important role on the metabolism of a variety of drugs. Bismuth drugs have been used to treat gastrointestinal disorder and Helicobacter pylori infection for decades without exerting acute toxicity. They were found to interact with a wide variety of biomolecules, but the major metabolic pathway remains unknown. For the first time (to our knowledge), we systematically and quantitatively studied the metabolism of bismuth in human cells. Our data demonstrated that over 90% of bismuth was passively absorbed, conjugated to glutathione, and transported into vesicles by MRP transporter. Mathematical modeling of the system reveals an interesting phenomenon. Passively absorbed bismuth consumes intracellular glutathione, which therefore activates de novo biosynthesis of glutathione. Reciprocally, sequestration by glutathione facilitates the passive uptake of bismuth and thus completes a self-sustaining positive feedback circle. This mechanism robustly removes bismuth from both intra- and extracellular space, protecting critical systems of human body from acute toxicity. It elucidates the selectivity of bismuth drugs between human and pathogens that lack of glutathione, such as Helicobacter pylori, opening new horizons for further drug development. PMID:25737551

  7. MicroRNA-873 mediates multidrug resistance in ovarian cancer cells by targeting ABCB1.

    PubMed

    Wu, Di-di; Li, Xue-Song; Meng, Xiao-Na; Yan, Jing; Zong, Zhi-Hong

    2016-08-01

    Ovarian cancer is commonly treated with cisplatin and paclitaxel combination chemotherapy; however, ovarian cancer cells often develop resistance to these drugs. Increasingly, microRNAs (miRNAs) including miR-873 have been implicated in drug resistance in many cancers, but the role of miR-873 in ovarian cancer remains unknown. MTT cell viability assays revealed that the sensitivities of ovarian cancer lines to cisplatin and paclitaxel increased following transfection with miR-873 (P < 0.05). After predicting the miR-873 binding region in the 3'-untranslated region of ABCB1, dual-luciferase reporter assay confirmed this prediction. RT-PCR and Western blotting revealed that MDR1 expression was significantly downregulated after transfection with miR-873 and upregulated after transfection with anti-miR-873 at both mRNA and protein levels compared to negative controls (P < 0.05). Experiments in a mouse xenograft model confirmed that intratumoral administration of miR-873 could enhance the efficacy of cisplatin in inhibiting tumor growth in ovarian cancer in vivo (P < 0.05). ABCB1 overexpression reduced sensitivities of ovarian cancer lines OVCAR3 and A2780 to cisplatin and paclitaxel, which can be reversed by miR-873 mimic transfection (P < 0.05). In summary, we demonstrated that overexpression of miR-873 increased the sensitivity of ovarian cancer cells to cisplatin and paclitaxel by targeting MDR1 expression. Our findings suggest that combination therapies with chemotherapy agents and miR-873 may suppress drug resistance in ovarian cancer.

  8. P-glycoprotein antagonists confer synergistic sensitivity to short-chain ceramide in human multidrug resistant cancer cells

    PubMed Central

    Chapman, Jacqueline V.; Gouazé-Andersson, Valérie; Karimi, Ramin; Messner, Maria C; Cabot, Myles C.

    2011-01-01

    P-glycoprotein (P-gp) antagonists inhibit ceramide metabolism at the juncture of glycosylation. The purpose of this study was to test whether targeting P-gp would be a viable alternative to targeting glucosylceramide synthase (GCS) for enhancing ceramide cytotoxicity. A2780 wild-type, and multidrug resistant 2780AD and NCI/ADR-RES human ovarian cancer cell lines and the cell-permeable ceramide analog, C6-ceramide (C6-cer), were employed. Compared to P-gp-poor A2780 cells, P-gp-rich 2780AD cells converted 3.7-fold more C6-cer to nontoxic C6-glucosylceramide (C6-GC), whereas cell-free GCS activities were equal. 2780AD cells displayed resistance to C6-cer (10 μM) that was reversed by inclusion of the P-gp antagonist tamoxifen (5 μM) but not by inclusion of a GCS inhibitor. Co-administration of C6-cer and P-gp antagonists was also effective in NCI/ADR-RES cells. For example, C6-cer, VX-710 (Biricodar), and cyclosporin A (cyc A) exposure resulted in viabilities of ~90% of control; however, C6-cer/VX-710 and C6-cer/cyc A additions were synergistic and resulted in viabilities of 22 and 17%, respectively. Further, whereas C6-ceramide and cyc A imparted 1.5- and zero-fold increases in caspase 3/7 activity, the combination produced a 3.5-fold increase. Although the upstream elements of cell death have not been elucidated, the novel C6-ceramide/P-gp antagonist combination merits further study and assessment of clinical translational potential. PMID:21396934

  9. Antiproliferative and proapoptotic effects of a pyrrole containing arylthioindole in human Jurkat leukemia cell line and multidrug-resistant Jurkat/A4 cells

    PubMed Central

    Philchenkov, Alex A; Zavelevich, Michael P; Tryndyak, Volodymyr P; Kuiava, Ludmila M; Blokhin, Dmitry Yu; Miura, Koh; Silvestri, Romano; Pogribny, Igor P

    2015-01-01

    Recently, a series of novel arylthioindole compounds, potent inhibitors of tubulin polymerization and cancer cell growth, were synthesized. In the present study the effects of 2-(1H-pyrrol-3-yl)-3-((3,4,5-trimethoxyphenyl)thio)-1H-indole (ATI5 compound) on cell proliferation, cell cycle progression, and induction of apoptosis in human T-cell acute leukemia Jurkat cells and their multidrug resistant Jurkat/A4 subline were investigated. Treatment of the Jurkat cells with the ATI5 compound for 48 hrs resulted in a strong G2/M cell cycle arrest and p53-independent apoptotic cell death accompanied by the induction of the active form of caspase-3 and poly(ADP-ribose) polymerase-1 (PARP-1) cleavage. ATI5 treatment also caused non-cell death related mitotic arrest in multidrug resistant Jurkat/A4 cells after 48 hrs of treatment suggesting promising opportunities for the further design of pyrrole-containing ATI compounds as anticancer agents. Cell death resistance of Jurkat/A4 cells to ATI5 compound was associated with alterations in the expression of pro-survival and anti-apoptotic protein-coding and microRNA genes. More importantly, findings showing that ATI5 treatment induced p53-independent apoptosis are of great importance from a therapeutic point of view since p53 mutations are common genetic alterations in human neoplasms. PMID:26785947

  10. Modulation of P-glycoprotein-mediated multidrug resistance in K562 leukemic cells by indole-3-carbinol

    SciTech Connect

    Arora, Annu; Seth, Kavita; Kalra, Neetu; Shukla, Yogeshwer . E-mail: yogeshwer_shukla@hotmail.com

    2005-02-01

    Resistance to chemotherapeutic drugs is one of the major problems in the treatment of cancer. P-glycoprotein (P-gp) encoded by the mdr gene is a highly conserved protein, acts as a multidrug transporter, and has a major role in multiple drug resistance (MDR). Targeting of P-gp by naturally occurring compounds is an effective strategy to overcome MDR. Indole-3-carbinol (I3C), a glucosinolates present in cruciferous vegetables, is a promising chemopreventive agent as it is reported to possess antimutagenic, antitumorigenic, and antiestrogenic properties in experimental studies. In the present investigation, the potential of I3C to modulate P-gp expression was evaluated in vinblastine (VBL)-resistant K562 human leukemic cells. The resistant K562 cells (K562/R10) were found to be cross-resistant to vincristine (VCR), doxorubicin (DXR), and other antineoplastic agents. I3C at a nontoxic dose (10 x 10{sup -3} M) enhanced the cytotoxic effects of VBL time dependently in VBL-resistant human leukemia (K562/R10) cells but had no effect on parent-sensitive cells (K562/S). The Western blot analysis of K 562/R 10 cells showed that I3C downregulates the induced levels of P-gp in resistant cells near to normal levels. The quantitation of immunocytochemically stained K562/R10 cells showed 24%, 48%, and 80% decrease in the levels of P-gp by I3C for 24, 48, and 72 h of incubation. The above features thus indicate that I3C could be used as a novel modulator of P-gp-mediated multidrug resistance in vitro and may be effective as a dietary adjuvant in the treatment of MDR cancers.

  11. Selective Toxicity of NSC 73306 in MDR1-positive cells as a New Strategy to Circumvent Multidrug Resistance in Cancer

    PubMed Central

    Ludwig, Joseph A.; Martin, Scott E.; Chu, Benjamin F.; Cardarelli, Carol; Sauna, Zuben E.; Caplen, Natasha J.; Fales, Henry M.; Ambudkar, Suresh V.; Weinstein, John N.

    2006-01-01

    ATP-binding cassette (ABC) proteins include the best known mediators of resistance to anticancer drugs. In particular, ABCB1 (MDR1/P-gp) extrudes many types of drugs from cancer cells, thereby conferring resistance to those agents. Attempts to overcome P-gp-mediated drug resistance using specific inhibitors of P-gp has had limited success, and has faced many therapeutic challenges. As an alternative approach to using P-gp inhibitors, we characterize a thiosemicarbazone derivative (NSC73306) identified in a generic screen as a compound that exploits, rather than suppresses, P-gp function to induce cytotoxicity. Cytotoxic activity of NSC73306 was evaluated in vitro using human epidermoid, ovarian, and colon cancer cell lines expressing various levels of P-gp. Our findings suggest that cells become hypersensitive to NSC73306 in proportion to the increased P-gp function and multidrug resistance (MDR). Abrogation of both sensitivity to NSC73306 and resistance to P-gp substrate anticancer agents occurred with specific inhibition of P-gp function using either a P-gp inhibitor (PSC833, XR9576) or RNA interference (RNAi), suggesting that cytotoxicity was linked to MDR1 function, not to other, nonspecific factors arising during the generation of resistant or transfected cells. Molecular characterization of cells selected for resistance to NSC73306 revealed loss of P-gp expression and consequent loss of the MDR phenotype. Although hypersensitivity to NSC73306 required functional expression of P-gp, biochemical assays revealed no direct interaction between NSC73306 and P-gp. This work demonstrates that NSC73306 kills cells with intrinsic or acquired P-gp-induced MDR and indirectly acts to eliminate resistance to MDR1 substrates. PMID:16651436

  12. Psoralen reverses the P-glycoprotein-mediated multidrug resistance in human breast cancer MCF-7/ADR cells.

    PubMed

    Jiang, Jingru; Wang, Xiaohong; Cheng, Kai; Zhao, Wanzhong; Hua, Yitong; Xu, Chengfeng; Yang, Zhenlin

    2016-06-01

    The resistance of cancer to chemotherapeutic agents is a major obstacle during chemotherapy. Clinical multidrug resistance (MDR) is commonly mediated by membrane drug efflux pumps, including ATP‑binding cassette subfamily B member 1, also termed P-glycoprotein (P-gp). P-gp is a membrane transporter encoded by the MDR1 gene. The current study aimed to investigate the impact of psoralen on the expression and function of P‑gp. The 10% inhibitory concentration (IC10) of psoralen, and its capacity to reduce MDR in adriamycin (ADR)‑resistant MCF‑7/ADR cells were determined using MTT assay. The ability of psoralen to modulate the transport activity of P‑gp in MCF‑7/ADR cells was evaluated by measuring the accumulation and efflux of rhodamine 123 (Rh 123) and adriamycin with flow cytometry. The present study evaluated the mRNA level of MDR1 in MCF‑7 and MCF‑7/ADR cells treated with psoralen using reverse transcription-quantitative polymerase chain reaction. The protein expression level of P‑gp was examined by western blot analysis. The current study demonstrated that the IC10 of psoralen in MCF‑7/ADR cells was 8 µg/ml. At 8 µg/ml, psoralen reduced MDR and the sensitivity of the MCF‑7/ADR cells to ADR compared with untreated cells. Additionally, psoralen significantly increased the intracellular accumulation of ADR and Rh 123. However, the IC10 of psoralen did not affect the protein expression levels of P‑gp or mRNA levels of MDR1 (P>0.05). Psoralen reduces MDR by inhibiting the efflux function of P‑gp, which may be important for increasing the efficiency of chemotherapy and improving the clinical protocols aiming to reverse P-gp-mediated MDR.

  13. TPGS2k/PLGA nanoparticles for overcoming multidrug resistance by interfering mitochondria of human alveolar adenocarcinoma cells.

    PubMed

    Wang, Dong-Fang; Rong, Wen-Ting; Lu, Yu; Hou, Jie; Qi, Shan-Shan; Xiao, Qing; Zhang, Jue; You, Jin; Yu, Shu-Qin; Xu, Qian

    2015-02-25

    In this study, we successfully synthesized d-α-tocopheryl polyethylene glycol 2000 succinate (TPGS2k) and prepared TPGS2k-modified poly(lactic-co-glycolic acid) nanoparticles (TPGS2k/PLGA NPs) loaded with 7-ethyl-10-hydroxycamptothecin (SN-38), designated TPGS2k/PLGA/SN-38 NPs. Characterization measurements showed that TPGS2k/PLGA/SN-38 NPs displayed flat and spheroidal particles with diameters of 80-104 nm. SN-38 was encapsulated in TPGS2k emulsified PLGA NPs with the entrapment efficiency and loading rates of SN-38 83.6 and 7.85%, respectively. SN-38 could release constantly from TPGS2k/PLGA/SN-38 NPs in vitro. TPGS2k/PLGA/SN-38 NPs induced significantly higher cytotoxicity on A549 cells and the multidrug resistance (MDR) cell line (A549/DDP cells and A549/Taxol cells) compared with free SN-38. Further studies on the mechanism of the NPs in increasing the death of MDR cells showed that following the SN-38 releasing into cytoplasm the remaining TPGS2k/PLGA NPs could reverse the P-gp mediated MDR via interfering with the structure and function of mitochondria and rather than directly inhibiting the enzymatic activity of P-gp ATPase. Therefore, TPGS2k/PLGA NPs can reduce the generation of ATP and the release of energy for the requisite of P-gp efflux transporters. The results indicated that TPGS2k/PLGA NPs could become the nanopharmaceutical materials with the capability to reversal MDR and improve anticancer effects of some chemotherapy drugs as P-gp substrates.

  14. Targeting P-glycoprotein expression and cancer cell energy metabolism: combination of metformin and 2-deoxyglucose reverses the multidrug resistance of K562/Dox cells to doxorubicin.

    PubMed

    Xue, Chaojun; Wang, Changyuan; Liu, Qi; Meng, Qiang; Sun, Huijun; Huo, Xiaokui; Ma, Xiaodong; Liu, Zhihao; Ma, Xiaochi; Peng, Jinyong; Liu, Kexin

    2016-07-01

    P-glycoprotein (P-gp) is one of the major obstacles to efficiency of cancer chemotherapy. Here, we investigated whether combination of metformin and 2-deoxyglucose reverses the multidrug resistance (MDR) of K562/Dox cells and tried to elucidate the possible mechanisms. The combination of metformin and 2-deoxyglucose selectively enhanced the cytotoxicity of doxorubicin against K562/Dox cells. Metformin was not a substrate of P-gp but suppressed the elevated level of P-gp in K562/Dox cells. The downregulation of P-gp may be partly attributed to the inhibition of extracellular signal-regulated kinase pathway. The addition of 2-deoxyglucose to metformin initiated a strong metabolic stress in both K562 and K562/Dox cells. Combination of metformin and 2-deoxyglucose inhibited glucose uptake and lactate production in K562 and K562/Dox cells leading to a severe depletion in ATP and a enhanced autophagy. Above all, P-gp substrate selectively aggravated this ATP depletion effect and increased cell apoptosis in K562/Dox cells. In conclusion, metformin decreases P-gp expression in K562/Dox cells via blocking phosphorylation of extracellular signal-regulated kinase. P-gp substrate increases K562/Dox cell apoptosis via aggravating ATP depletion induced by combination of metformin and 2-deoxyglucose. Our observations highlight the importance of combination of metformin and 2-deoxyglucose in reversing multidrug resistance.

  15. A phenolic ester from Aglaia loheri leaves reveals cytotoxicity towards sensitive and multidrug-resistant cancer cells

    PubMed Central

    2013-01-01

    Background Bioactivity-guided fractionation of extracts of Aglaia loheri Blanco (Meliaceae) yielded a cytotoxic isolate, termed Maldi 531.2[M + H]+. This phenolic ester was further investigated for its in vitro cytotoxicity toward human CCRF-CEM leukemia cells and their multi-drug resistant (MDR) subline, CEM/ADR5000. The intrinsic mitochondrial membrane potential (ΔΨm) and induction of apoptosis by this isolate were evaluated. Methods Chromatography techniques, mass spectrometry and proton NMR were employed to isolate Maldi 531.2[M + H]+. XTT cell proliferation and viability assay was used for cytotoxic test, and JC-1[5’,5’,6,6’,-tetrachloro-1,1’,3,3’-tetraethylbenzimidazoyl carbocyanine iodide was used to assess ΔΨm and initiation of apoptosis; Annexin V/FITC-PI staining was employed to analyse apoptosis. Results Maldi 531.2[M + H]+ was cytotoxic towards both CCRF-CEM and CEM/ADR5000 cells with IC50 values of 0.02 and 0.03 μM, respectively. The mitochondrial membrane potential (ΔΨm) of MDR cells was significantly reduced in a dose-dependent manner leading to apoptosis as detected by flow cytometric Annexin V-FITC/ PI staining. Conclusion Maldi 531.2[M + H]+ may be a potential anti-cancer drug candidate whose mode of action include reduction of the mitochondrial membrane potential and induction of apoptosis. PMID:24160768

  16. pH-Responsive therapeutic solid lipid nanoparticles for reducing P-glycoprotein-mediated drug efflux of multidrug resistant cancer cells.

    PubMed

    Chen, Hsin-Hung; Huang, Wen-Chia; Chiang, Wen-Hsuan; Liu, Te-I; Shen, Ming-Yin; Hsu, Yuan-Hung; Lin, Sung-Chyr; Chiu, Hsin-Cheng

    2015-01-01

    In this study, a novel pH-responsive cholesterol-PEG adduct-coated solid lipid nanoparticles (C-PEG-SLNs) carrying doxorubicin (DOX) capable of overcoming multidrug resistance (MDR) breast cancer cells is presented. The DOX-loaded SLNs have a mean hydrodynamic diameter of ~100 nm and a low polydispersity index (under 0.20) with a high drug-loading efficiency ranging from 80.8% to 90.6%. The in vitro drug release profiles show that the DOX-loaded SLNs exhibit a pH-controlled drug release behavior with the maximum and minimum unloading percentages of 63.4% at pH 4.7 and 25.2% at pH 7.4, respectively. The DOX-loaded C-PEG-SLNs displayed a superior ability in inhibiting the proliferation of MCF-7/MDR cells. At a DOX concentration of 80 μM, the cell viabilities treated with C-PEG-SLNs were approximately one-third of the group treated with free DOX. The inhibition activity of C-PEG-SLNs could be attributed to the transport of C-PEG to cell membrane, leading to the change of the composition of the cell membrane and thus the inhibition of permeability glycoprotein activity. This hypothesis is supported by the confocal images showing the accumulation of DOX in the nuclei of cancer cells and the localization of C-PEG on the cell membranes. The results of in vivo study further demonstrated that the DOX delivered by the SLNs accumulates predominantly in tumor via enhanced permeability and retention effect, the enhanced passive tumor accumulation due to the loose intercellular junctions of endothelial cells lining inside blood vessels at tumor site, and the lack of lymphatic drainage. The growth of MCF-7/MDR xenografted tumor on Balb/c nude mice was inhibited to ~400 mm(3) in volume as compared with the free DOX treatment group, 1,140 mm(3), and the group treated with 1,2 distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)] solid lipid nanoparticles, 820 mm(3). Analysis of the body weight of nude mice and the histology of organs and tumor after the

  17. An Inactivated Antibiotic-Exposed Whole-Cell Vaccine Enhances Bactericidal Activities Against Multidrug-Resistant Acinetobacter baumannii

    PubMed Central

    Shu, Meng-Hooi; MatRahim, NorAziyah; NorAmdan, NurAsyura; Pang, Sui-Ping; Hashim, Sharina H.; Phoon, Wai-Hong; AbuBakar, Sazaly

    2016-01-01

    Vaccination may be an alternative treatment for infection with multidrug-resistance (MDR) Acinetobacter baumannii. The study reported here evaluated the bactericidal antibody responses following immunization of mice using an inactivated whole-cell vaccine derived from antibiotic-exposed MDR A. baumannii (I-M28-47-114). Mice inoculated with I-M28-47 (non-antibiotic-exposed control) and I-M28-47-114 showed a high IgG antibody response by day 5 post-inoculation. Sera from mice inoculated with I-M28-47-114 collected on day 30 resulted in 80.7 ± 12.0% complement-mediated bacteriolysis in vitro of the test MDR A. baumannii treated with imipenem, which was a higher level of bacteriolysis over sera from mice inoculated with I-M28-47. Macrophage-like U937 cells eliminated 49.3 ± 11.6% of the test MDR A. baumannii treated with imipenem when opsonized with sera from mice inoculated with I-M28-47-114, which was a higher level of elimination than observed for test MDR A. baumannii opsonized with sera from mice inoculated with I-M28-47. These results suggest that vaccination with I-M28-47-114 stimulated antibody responses capable of mounting high bactericidal killing of MDR A. baumannii. Therefore, the inactivated antibiotic-exposed whole-cell vaccine (I-M28-47-114) has potential for development as a candidate vaccine for broad clearance and protection against MDR A. baumannii infections. PMID:26923424

  18. Genomic and transcriptomic profiling of resistant CEM/ADR-5000 and sensitive CCRF-CEM leukaemia cells for unravelling the full complexity of multi-factorial multidrug resistance

    PubMed Central

    Kadioglu, Onat; Cao, Jingming; Kosyakova, Nadezda; Mrasek, Kristin; Liehr, Thomas; Efferth, Thomas

    2016-01-01

    We systematically characterised multifactorial multidrug resistance (MDR) in CEM/ADR5000 cells, a doxorubicin-resistant sub-line derived from drug-sensitive, parental CCRF-CEM cells developed in vitro. RNA sequencing and network analyses (Ingenuity Pathway Analysis) were performed. Chromosomal aberrations were identified by array-comparative genomic hybridisation (aCGH) and multicolour fluorescence in situ hybridisation (mFISH). Fifteen ATP-binding cassette transporters and numerous new genes were overexpressed in CEM/ADR5000 cells. The basic karyotype in CCRF-CEM cells consisted of 47, XX, der(5)t(5;14) (q35.33;q32.3), del(9) (p14.1), +20. CEM/ADR5000 cells acquired additional aberrations, including X-chromosome loss, 4q and 14q deletion, chromosome 7 inversion, balanced and unbalanced two and three way translocations: t(3;10), der(3)t(3;13), der(5)t(18;5;14), t(10;16), der(18)t(7;18), der(18)t(21;18;5), der(21;21;18;5) and der(22)t(9;22). CCRF-CEM consisted of two and CEM/ADR5000 of five major sub-clones, indicating genetic tumor heterogeneity. Loss of 3q27.1 in CEM/ADR5000 caused down-regulation of ABCC5 and ABCF3 expression, Xq28 loss down-regulated ABCD1 expression. ABCB1, the most well-known MDR gene, was 448-fold up-regulated due to 7q21.12 amplification. In addition to well-known drug resistance genes, numerous novel genes and genomic aberrations were identified. Transcriptomics and genetics in CEM/AD5000 cells unravelled a range of MDR mechanisms, which is much more complex than estimated thus far. This may have important implications for future treatment strategies. PMID:27824156

  19. Multidrug resistance: a transport system of antitumor agents and xenobiotics.

    PubMed

    Tsuruo, T

    1990-01-01

    Resistance of tumors to a variety of chemotherapeutic agents presents a major problem in cancer treatment. Resistance to such agents as doxorubicin, Vinca alkaloids, and actinomycin D can be acquired by tumor cells after treatment with a single drug. The gene responsible for multidrug resistance, termed mdr1, encodes a membrane glycoprotein (P-glycoprotein) that acts as a pump to transport various cytotoxic agents including various xenobiotics out of the cell. The amount of P-glycoprotein expression has been measured in tumor samples and was found to be elevated in intrinsically drug-resistant cancers of the colon, kidney, and adrenal as well as in some tumors that acquired drug resistance after chemotherapy. The protein was also found to be elevated in cells treated with xenobiotics. P-glycoprotein has been shown to bind anticancer drugs and several resistance-reversing agents including calcium channel blockers, and to be an ATPase. We recently reconstituted the purified P-glycoprotein into artificial liposomes. Reconstituted P-glycoprotein showed ATPase activity, ATP-dependent drug-transport activity, and calcium channel blocker-binding activity. This model provides many advantages for studies of the biochemical functions of P-glycoprotein. In addition to these basic interests, the protein is of considerable interest as a target for cancer chemotherapy because it appears to be involved in both acquired multidrug resistance and intrinsic drug resistance in human cancer. The selective killing of tumor cells expressing P-glycoprotein could be very important in future cancer therapy.

  20. Characterization of Siphoviridae phage Z and studying its efficacy against multidrug-resistant Klebsiella pneumoniae planktonic cells and biofilm.

    PubMed

    Jamal, Muhsin; Hussain, Tahir; Das, Chythanya Rajanna; Andleeb, Saadia

    2015-04-01

    Biofilm has many serious consequences for public health and is a major virulence factor contributing to the chronicity of infections. The aim of the current study was to isolate and characterize a bacteriophage that inhibits multidrug-resistant Klebsiella pneumonia (M) in planktonic form as well as biofilm. This phage, designated bacteriophage Z, was isolated from wastewater. Its adsorption rate to its host bacterium was significantly enhanced by MgCl2 and CaCl2. It has a wide range of pH and heat stability. From its one-step growth, latent time and burst size were determined to be 24 min and about 320 virions per cell, respectively. As analysed by transmission electron microscopy, phage Z had an icosahedral head of width 76±10 nm, length 92±14 nm and icosahedron side 38 nm, and a non-contractile tail 200±15 nm long and 14-29 nm wide. It belongs to the family Siphoviridae in the order Caudovirales. Six structural proteins ranging from 18 to 65 kDa in size were revealed by SDS-PAGE. The genome was found to comprise double-stranded DNA with an approximate size of 36 kb. Bacteria were grown in suspension and as biofilms to compare the susceptibility of both phenotypes to the phage lytic action. Phage Z was effective in reducing biofilm biomass after 24 and 48 h, showing more than twofold and threefold reduction, respectively. Biofilm cells and stationary-phase planktonic bacteria were killed at a lower rate than exponential-phase planktonic bacteria.

  1. Effect of glucose transport inhibitors on vincristine efflux in multidrug-resistant murine erythroleukaemia cells overexpressing the multidrug resistance-associated protein (MRP) and two glucose transport proteins, GLUT1 and GLUT3.

    PubMed Central

    Martell, R. L.; Slapak, C. A.; Levy, S. B.

    1997-01-01

    The relationship between mammalian facilitative glucose transport proteins (GLUT) and multidrug resistance was examined in two vincristine (VCR)-selected murine erythroleukaemia (MEL) PC4 cell lines. GLUT proteins, GLUT1 and GLUT3, were constitutively coexpressed in the parental cell line and also in the VCR-selected cell lines. Increased expression of the GLUT1 isoform was noted both in the PC-V40 (a non-P-glycoprotein, mrp-overexpressing subline) and in the more resistant PC-V160 (overexpressing mrp and mdr3) cell lines. Overexpression of GLUT3 was detected only in the PC-V160 subline. An increased rate of facilitative glucose transport (Vmax) and level of plasma membrane GLUT protein expression paralleled increased VCR resistance, active VCR efflux and decreased VCR steady-state accumulation in these cell lines. Glucose transport inhibitors (GTIs), cytochalasin B (CB) and phloretin blocked the active efflux and decreased steady-state accumulation of VCR in the PC-V40 subline. GTIs did not significantly affect VCR accumulation in the parental or PC-V160 cells. A comparison of protein sequences among GLUT1, GLUT3 and MRP revealed a putative cytochalasin B binding site in MRP, which displayed 44% sequence similarity/12% identity with that previously identified in GLUT1 and GLUT3; these regions also exhibited a similar hydropathy plot pattern. The findings suggested that CB bound to MRP and directly or indirectly lowered VCR efflux and/or CB bound to one or both GLUT proteins, which acted to lower the VCR efflux mediated by MRP. This is the first report of a non-neuronal murine cell line that expressed GLUT3. Images Figure 3 PMID:9010020

  2. Patients with Multidrug-Resistant Tuberculosis Display Impaired Th1 Responses and Enhanced Regulatory T-Cell Levels in Response to an Outbreak of Multidrug-Resistant Mycobacterium tuberculosis M and Ra Strains▿

    PubMed Central

    Geffner, Laura; Yokobori, Noemí; Basile, Juan; Schierloh, Pablo; Balboa, Luciana; Romero, María Mercedes; Ritacco, Viviana; Vescovo, Marisa; González Montaner, Pablo; Lopez, Beatriz; Barrera, Lucía; Alemán, Mercedes; Abatte, Eduardo; Sasiain, María C.; de la Barrera, Silvia

    2009-01-01

    In Argentina, multidrug-resistant tuberculosis (MDR-TB) outbreaks emerged among hospitalized patients with AIDS in the early 1990s and thereafter disseminated to the immunocompetent community. Epidemiological, bacteriological, and genotyping data allowed the identification of certain MDR Mycobacterium tuberculosis outbreak strains, such as the so-called strain M of the Haarlem lineage and strain Ra of the Latin America and Mediterranean lineage. In the current study, we evaluated the immune responses induced by strains M and Ra in peripheral blood mononuclear cells from patients with active MDR-TB or fully drug-susceptible tuberculosis (S-TB) and in purified protein derivative-positive healthy controls (group N). Our results demonstrated that strain M was a weaker gamma interferon (IFN-γ) inducer than H37Rv for group N. Strain M induced the highest interleukin-4 expression in CD4+ and CD8+ T cells from MDR- and S-TB patients, along with the lowest cytotoxic T-lymphocyte (CTL) activity in patients and controls. Hence, impairment of CTL activity is a hallmark of strain M and could be an evasion mechanism employed by this strain to avoid the killing of macrophages by M-specific CTL effectors. In addition, MDR-TB patients had an increased proportion of circulating regulatory T cells (Treg cells), and these cells were further expanded upon in vitro M. tuberculosis stimulation. Experimental Treg cell depletion increased IFN-γ expression and CTL activity in TB patients, with M- and Ra-induced CTL responses remaining low in MDR-TB patients. Altogether, these results suggest that immunity to MDR strains might depend upon a balance between the individual host response and the ability of different M. tuberculosis genotypes to drive Th1 or Th2 profiles. PMID:19720756

  3. Modulation of P-glycoprotein mediated drug accumulation in multidrug resistant CCRF VCR-1000 cells by chemosensitisers.

    PubMed

    Boer, R; Gekeler, V; Ulrich, W R; Zimmermann, P; Ise, W; Schödl, A; Haas, S

    1996-05-01

    P-glycoprotein (PGP) mediated transport of cytostatic drugs out of resistant cancer cells is a major cause of experimental and probably also of clinical multidrug resistance, which often leads to treatment failure during chemotherapy. The broad substrate specificity of PGP strongly restricts effective chemotherapy and diminishes the patients' prognosis. Inhibition of PGP's pumping function by chemosensitisers is one way to restore cellular responsiveness to otherwise ineffective cytostatics. Clinical trials with several chemosensitisers are under way. To date, it is not clear whether a certain chemosensitiser potentiates the action of different cytostatic drugs, transported by PGP equally well, or whether the chemosensitising potency is dependent on the cytostatic drugs used. Therefore, we compared the effects of five potent chemosensitisers on cellular accumulation using [3H]daunomycin, [3H]vincristine and rhodamine-123 as substrates for PGP. The acridonecarboxamide derivative GF 120918 was the most potent compound and a half-maximal effect was seen at concentrations ranging from 5 nM for rhodamine-123 accumulation to 14 and 19 nM for [3H]vincristine or [3H]daunomycin accumulation, respectively. The new chemosensitiser B9203-016 was slightly less effective than GF 120918 in all three test systems. Dexniguldipine was of intermediate potency with half-maximal effects at concentrations between 62 and 194 nM. The cyclic undecapeptide SDZ PSC 833 showed somewhat lower potency ranging from 151 to 331 nM. Cyclosporin A was less potent than SDZ PSC 833. Furthermore, enhancement of drug accumulation produced by each chemosensitiser was similar, regardless of which PGP substrate was measured, that is, the rank order of potency to increase accumulation was the same in each of the assays used. Our data point to similar, if not identical, mechanisms of drug transport by PGP and inhibition of drug transport by chemosensitisers at least for the substrates rhodamine-123

  4. Co-encapsulation of chrysophsin-1 and epirubicin in PEGylated liposomes circumvents multidrug resistance in HeLa cells.

    PubMed

    Lo, Yu-Li; Tu, Wei-Chen

    2015-12-05

    Chrysophsin-1, an amphipathic alpha-helical antimicrobial peptide, is isolated from the gills of the red sea bream and possesses different structure and mechanism(s) in comparison with traditional multidrug resistance (MDR) modulators. For the purpose of reducing off-target normal cell toxicity, it is rational to incorporate chrysophsin-1 and epirubicin in a PEGylated liposomal formulation. In the present study, we report a multifunctional liposomes with epirubicin as an antineoplastic agent and an apoptosis inducer, as well as chrysophsin-1 as a MDR transporter inhibitor and an apoptosis modulator in human cervical cancer HeLa cells. Co-incubation of HeLa cells with PEGylated liposomal formulation of epirubicin and chrysophsin-1 resulted in a significant increase in the cytotoxicity of epirubicin. The liposomal formulations of epirubicin and/or chrysophsin-1 were shown to considerably improve the intracellular H2O2 and O2(-) levels of HeLa cells. Furthermore, these treatments were found to extensively reduce mRNA expression levels of MDR1, MRP1, and MRP2. The addition of chrysophsin-1 in liposomes was demonstrated to substantially enhance the intracellular accumulation of epirubicin in HeLa cells. Moreover, the PEGylated liposomes of epirubicin and chrysophsin-1 were also found to significantly increase the mRNA expressions of p53, Bax, and Bcl-2. The ratio of Bax to Bcl-2 was noticeably amplified in the presence of these formulations. Apoptosis induction was also validated by chromatin condensation, a reduction in mitochondrial membrane potential, the increased sub-G1 phase of cell cycle, and more populations of apoptosis using annexin V/PI assay. These formulations were verified to increase the activity and mRNA expression levels of caspase-9 and caspases-3. Collectively, our findings provide the first evidence that cotreatment with free or liposomal chrysophsin-1 and epirubicin leads to cell death in human cervical cancer cells through the ROS

  5. Knockdown of nucleophosmin by RNA interference reverses multidrug resistance in resistant leukemic HL-60 cells.

    PubMed

    Lin, Minhui; Hu, Jianda; Liu, Tingbo; Li, Jing; Chen, Buyuan; Chen, Xinji

    2013-09-01

    Nucleophosmin, a multifunctional nucleolar phosphoprotein, is involved in many cellular activities. However, the role of NPM in drug-resistance of leukemia has not yet been explored. We designed and selected one shRNA targeting on NPM gene transduction into HL-60 and HL-60/ADR cell lines (an adriamycin resistant cell line) by lentivirus. Cell proliferation, apoptosis and differentiation were assessed. The expressions of the related genes and proteins were detected by real-time quantitative RT-PCR and Western blotting. The results showed obvious down-regulation of NPM mRNA and protein levels after NPM RNAi. NPM-targeted RNAi also resulted in many cellular changes, such as, suppressing cell proliferation and inducing cell differentiation. Down-regulation of NPM gene could arrest the cell cycle progression, an increase in the proportion of G0/G1 phase in knockdown groups. NPM gene silencing could also induce pro-apoptotic genes and proteins expression, and inhibit anti-apoptotic genes/proteins expression. Furthermore, IC50 of two chemotherapeutic agents (adriamycin and ADR; daunorubicin and DNR) to HL-60 and HL-60/ADR cells decreased, especially more remarkable on HL-60/ADR cells. IC50 of ADR on HL-60/ADR cells was reduced from 12.544 ± 0.851 μmol/L (before NPM RNAi) to 6.331 ± 0.522 μmol/L (after NPM RNAi), IC50 of DNR was reduced from 2.152 ± 0.143 μmol/L (before NPM RNAi) to 1.116 ± 0.093 μmol/L (after NPM RNAi). The relative reversal rate of HL-60/ADR cells on ADR was 50.2%, and on DNR was 48.9%. In conclusion, our results demonstrated that shRNA expression vectors could effectively reduce NPM expression and restore the drug sensitivity of resistant leukemic cells to conventional chemotherapeutic agents.

  6. Deletions of multidrug resistance gene loci in breast cancer leads to the down-regulation of its expression and predict tumor response to neoadjuvant chemotherapy

    PubMed Central

    Litviakov, Nikolai V.; Cherdyntseva, Nadezhda V.; Tsyganov, Matvey M.; Slonimskaya, Elena M.; Ibragimova, Marina K.; Kazantseva, Polina V.; Kzhyshkowska, Julia; Choinzonov, Eugeniy L.

    2016-01-01

    Neoadjuvant chemotherapy (NAC) is intensively used for the treatment of primary breast cancer. In our previous studies, we reported that clinical tumor response to NAC is associated with the change of multidrug resistance (MDR) gene expression in tumors after chemotherapy. In this study we performed a combined analysis of MDR gene locus deletions in tumor DNA, MDR gene expression and clinical response to NAC in 73 BC patients. Copy number variations (CNVs) in biopsy specimens were tested using high-density microarray platform CytoScanTM HD Array (Affymetrix, USA). 75%–100% persons having deletions of MDR gene loci demonstrated the down-regulation of MDR gene expression. Expression of MDR genes was 2–8 times lower in patients with deletion than in patients having no deletion only in post-NAC tumors samples but not in tumor tissue before chemotherapy. All patients with deletions of ABCB1 ABCB 3 ABCC5 gene loci – 7q21.1, 6p21.32, 3q27 correspondingly, and most patients having deletions in ABCC1 (16p13.1), ABCC2 (10q24), ABCG1 (21q22.3), ABCG2 (4q22.1), responded favorably to NAC. The analysis of all CNVs, including both amplification and deletion showed that the frequency of 13q14.2 deletion was 85% among patients bearing tumor with the deletion at least in one MDR gene locus versus 9% in patients with no deletions. Differences in the frequency of 13q14.2 deletions between the two groups were statistically significant (p = 2.03 ×10−11, Fisher test, Bonferroni-adjusted p = 1.73 × 10−8). In conclusion, our study for the first time demonstrates that deletion MDR gene loci can be used as predictive marker for tumor response to NAC. PMID:26799285

  7. Arsenite-loaded nanoparticles inhibit PARP-1 to overcome multidrug resistance in hepatocellular carcinoma cells

    PubMed Central

    Liu, Hanyu; Zhang, Zongjun; Chi, Xiaoqin; Zhao, Zhenghuan; Huang, Dengtong; Jin, Jianbin; Gao, Jinhao

    2016-01-01

    Hepatocellular carcinoma (HCC) is one of the highest incidences in cancers; however, traditional chemotherapy often suffers from low efficiency caused by drug resistance. Herein, we report an arsenite-loaded dual-drug (doxorubicin and arsenic trioxide, i.e., DOX and ATO) nanomedicine system (FeAsOx@SiO2-DOX, Combo NP) with significant drug synergy and pH-triggered drug release for effective treatment of DOX resistant HCC cells (HuH-7/ADM). This nano-formulation Combo NP exhibits the synergistic effect of DNA damage by DOX along with DNA repair interference by ATO, which results in unprecedented killing efficiency on DOX resistant cancer cells. More importantly, we explored the possible mechanism is that the activity of PARP-1 is inhibited by ATO during the treatment of Combo NP, which finally induces apoptosis of HuH-7/ADM cells by poly (ADP-ribosyl) ation suppression and DNA lesions accumulation. This study provides a smart drug delivery strategy to develop a novel synergistic combination therapy for effectively overcome drug- resistant cancer cells. PMID:27484730

  8. Arsenite-loaded nanoparticles inhibit PARP-1 to overcome multidrug resistance in hepatocellular carcinoma cells

    NASA Astrophysics Data System (ADS)

    Liu, Hanyu; Zhang, Zongjun; Chi, Xiaoqin; Zhao, Zhenghuan; Huang, Dengtong; Jin, Jianbin; Gao, Jinhao

    2016-08-01

    Hepatocellular carcinoma (HCC) is one of the highest incidences in cancers; however, traditional chemotherapy often suffers from low efficiency caused by drug resistance. Herein, we report an arsenite-loaded dual-drug (doxorubicin and arsenic trioxide, i.e., DOX and ATO) nanomedicine system (FeAsOx@SiO2-DOX, Combo NP) with significant drug synergy and pH-triggered drug release for effective treatment of DOX resistant HCC cells (HuH-7/ADM). This nano-formulation Combo NP exhibits the synergistic effect of DNA damage by DOX along with DNA repair interference by ATO, which results in unprecedented killing efficiency on DOX resistant cancer cells. More importantly, we explored the possible mechanism is that the activity of PARP-1 is inhibited by ATO during the treatment of Combo NP, which finally induces apoptosis of HuH-7/ADM cells by poly (ADP-ribosyl) ation suppression and DNA lesions accumulation. This study provides a smart drug delivery strategy to develop a novel synergistic combination therapy for effectively overcome drug- resistant cancer cells.

  9. The role of stereoselectivity of chemosensitizers in the reversal of multidrug resistance of mouse lymphoma cells.

    PubMed

    Szabó, D; Molnár, J

    1998-01-01

    The effect of three different stereoisomer pairs of CNS (central nervous system) active compounds was studied on the activity of human mdr1 p-glycoprotein. The methotrimeprazine, clopenthixol and butaclamol isomers had an antiproliferative effect (ID50) on the mdr1 expressing cells at 0.250 microgram/ml, while the parental cells were less sensitive having ID50 at 0.37-0.69 microgram/ml. Enantiomers of methotrimeprazine and clopenthixol had similar effectivity on the drug efflux of mdr cells. However, (-)butaclamol was found to inhibit mdr efflux-pump activity much more than the CNS active (+) isomer. Based on these results, tricyclic compounds does not seem to have stereoselectivity in methotrimeprazine and clopenthixol on the mdr reversal effect. In general, both active and inactive members of stereoisomers had a similar effect on the drug accumulation of the mdr cells. Therefore, hypothetically the CNS inactive member of stereoisomer pairs can be used as a resistance modifier without any risk in patients suffering from drug resistant cancer.

  10. Lysosome-mediated Cell Death and Autophagy-Dependent Multidrug Resistance in Breast Cancer

    DTIC Science & Technology

    2008-10-01

    with established links (Fig. 3); this result opens the possibility of hypothesis generation. For example, upregulation of NDRG1 in hypoxia [1] may...be tested in both parental cells and in resistant clones and may involve differential regulation by MYC and PTEN [2, 3] while downregulation of NDRG1 ...the hypoxia- inducible protein NDRG1 in pancreatic cancer. Br J Cancer, 2006. 95(3): p. 307-13. 2. Zhang, J., et al., Human differentiation-related

  11. R-Flurbiprofen Traps Prostaglandins within Cells by Inhibition of Multidrug Resistance-Associated Protein-4

    PubMed Central

    Wobst, Ivonne; Ebert, Lisa; Birod, Kerstin; Wegner, Marthe-Susanna; Hoffmann, Marika; Thomas, Dominique; Angioni, Carlo; Parnham, Michael J.; Steinhilber, Dieter; Tegeder, Irmgard; Geisslinger, Gerd; Grösch, Sabine

    2016-01-01

    R-flurbiprofen is the non-COX-inhibiting enantiomer of flurbiprofen and is not converted to S-flurbiprofen in human cells. Nevertheless, it reduces extracellular prostaglandin E2 (PGE2) in cancer or immune cell cultures and human extracellular fluid. Here, we show that R-flurbiprofen acts through a dual mechanism: (i) it inhibits the translocation of cPLA2α to the plasma membrane and thereby curtails the availability of arachidonic acid and (ii) R-flurbiprofen traps PGE2 inside of the cells by inhibiting multidrug resistance–associated protein 4 (MRP4, ABCC4), which acts as an outward transporter for prostaglandins. Consequently, the effects of R-flurbiprofen were mimicked by RNAi-mediated knockdown of MRP4. Our data show a novel mechanism by which R-flurbiprofen reduces extracellular PGs at physiological concentrations, particularly in cancers with high levels of MRP4, but the mechanism may also contribute to its anti-inflammatory and immune-modulating properties and suggests that it reduces PGs in a site- and context-dependent manner. PMID:28042832

  12. Effect of magnetic nanoparticles of Fe3O4 and wogonin on the reversal of multidrug resistance in K562/A02 cell line

    PubMed Central

    Cheng, Jian; Cheng, Lin; Chen, Baoan; Xia, Guohua; Gao, Chong; Song, Huihui; Bao, Wen; Guo, Qinglong; Zhang, Haiwei; Wang, Xuemei

    2012-01-01

    Background Multidrug resistance is the main obstacle to the efficiency of systemic chemotherapy against hematologic malignancy. This study investigated the reversible effect of the copolymer wogonin and daunorubicin coloaded into Fe3O4 magnetic nanoparticles, and the mechanism potentially involved. Methods The growth inhibition rate of K562/A02 cells was investigated by MTT assay, and apoptosis of cells and the intracellular daunorubicin concentration were detected by flow cytometry. Distribution of nanoparticles taken up by K562/A02 cells was observed under a transmission electron microscope and demonstrated by Prussian blue staining. The transcription level of MDR1 mRNA and expression of P-glycoprotein were determined by reverse transcriptase polymerase chain reaction and Western blotting assay, respectively. Results The reversible effect of daunorubicin-wogonin magnetic nanoparticles was 8.87-fold that of daunorubicin + wogonin and of daunorubicin magnetic nanoparticles. Transmission electron microscopy and Prussian blue staining revealed that the nanoparticles were located in the endosome vesicles of cytoplasm. Also, the apoptosis rate and accumulation of intracellular daunorubicin in the daunorubicin-wogonin magnetic nanoparticle group were significantly higher than that in the daunorubicin, daunorubicin + wogonin, and daunorubicin magnetic nanoparticle groups. Furthermore, transcription of MDR1 mRNA and expression of P-glycoprotein in K562/A02 cells were significantly downregulated in the daunorubicin-wogonin magnetic nanoparticle group compared with the other groups. Conclusion These findings suggest that the remarkable effects of the novel daunorubicin-wogonin magnetic nanoparticle formulation on multidrug resistant K562/A02 leukemia cells would be a promising strategy for overcoming multidrug resistance. PMID:22745547

  13. Asclepiasterol, a novel C21 steroidal glycoside derived from Asclepias curassavica, reverses tumor multidrug resistance by down-regulating P-glycoprotein expression

    PubMed Central

    Wang, Jun; Ma, Yan; Li, Wen-Xue; Jiang, Ren-Wang; Cai, Shao-Hui

    2016-01-01

    Multidrug resistance (MDR) mediated by P-glycoprotein (P-gp) is a major cause of cancer therapy failure. In this study, we identified a novel C21 steroidal glycoside, asclepiasterol, capable of reversing P-gp-mediated MDR. Asclepiasterol (2.5 and 5.0μM) enhanced the cytotoxity of P-gp substrate anticancer drugs in MCF-7/ADR and HepG-2/ADM cells. MDR cells were more responsive to paclitaxel in the presence of asclepiasterol, and colony formation of MDR cells was only reduced upon treatment with a combination of asclepiasterol and doxorubicin. Consistent with these findings, asclepiasterol treatment increased the intracellular accumulation of doxorubicin and rhodamine 123 (Rh123) in MDR cells. Asclepiasterol decreased expression of P-gp protein without stimulating or suppressing MDR1 mRNA levels. Asclepiasterol-mediated P-gp suppression caused inhibition of ERK1/2 phosphorylation in two MDR cell types, and EGF, an activator of the MAPK/ERK pathway, reversed the P-gp down-regulation, implicating the MAPK/ERK pathway in asclepiasterol-mediated P-gp down-regulation. These results suggest that asclepiasterol could be developed as a modulator for reversing P-gp-mediated MDR in P-gp-overexpressing cancer variants. PMID:27129170

  14. Asclepiasterol, a novel C21 steroidal glycoside derived from Asclepias curassavica, reverses tumor multidrug resistance by down-regulating P-glycoprotein expression.

    PubMed

    Yuan, Wei-Qi; Zhang, Rong-Rong; Wang, Jun; Ma, Yan; Li, Wen-Xue; Jiang, Ren-Wang; Cai, Shao-Hui

    2016-05-24

    Multidrug resistance (MDR) mediated by P-glycoprotein (P-gp) is a major cause of cancer therapy failure. In this study, we identified a novel C21 steroidal glycoside, asclepiasterol, capable of reversing P-gp-mediated MDR. Asclepiasterol (2.5 and 5.0μM) enhanced the cytotoxity of P-gp substrate anticancer drugs in MCF-7/ADR and HepG-2/ADM cells. MDR cells were more responsive to paclitaxel in the presence of asclepiasterol, and colony formation of MDR cells was only reduced upon treatment with a combination of asclepiasterol and doxorubicin. Consistent with these findings, asclepiasterol treatment increased the intracellular accumulation of doxorubicin and rhodamine 123 (Rh123) in MDR cells. Asclepiasterol decreased expression of P-gp protein without stimulating or suppressing MDR1 mRNA levels. Asclepiasterol-mediated P-gp suppression caused inhibition of ERK1/2 phosphorylation in two MDR cell types, and EGF, an activator of the MAPK/ERK pathway, reversed the P-gp down-regulation, implicating the MAPK/ERK pathway in asclepiasterol-mediated P-gp down-regulation. These results suggest that asclepiasterol could be developed as a modulator for reversing P-gp-mediated MDR in P-gp-overexpressing cancer variants.

  15. [Perspectives of inhibition of multidrug resistance during cancer chemotherapy, in vitro and in vivo experiments].

    PubMed

    Engi, Helga

    2009-03-29

    The development of pharmacological agents able to counteract the mechanisms of multidrug resistance in oncology has remained a major goal for the past ten years. Our purpose was to find multidrug resistance reversal agents less toxic than verapamil among various synthetic compounds: cinnamylidene ketones; 1,4-dihydropyridines; phenothiazines; heat shock 90 inhibitor peptides; betti base derivative of tylosin and among some naturally occurring plant derived jatrophane and lathyrane-type diterpenes. The first part of this thesis presents the inhibition of multidrug resistance through inhibition of the P-glycoprotein efflux pump in various cell lines. In general, the newly identified multidrug resistance modifiers were able to enhance the antiproliferative activity of selected anticancer drugs in a synergistic or additive way in in vitro experiments. The in vitro activity of betti base derivative of tylosin was confirmed by further in vivo efficacy studies in DBA/2 mice. As an alternative way of antitumor effect, apoptosis inductions of resistance modifiers were studied. The substituted dihydropyridine 13 was the most promising apoptosis inducer on mouse lymphoma cells. Human cytomegalovirus was used in a modified in vitro model for characterizing lathyrane compounds with antipromotion effect on human lung cancer cells. All the six macrocyclic lathyrane-type diterpenoids reduced the promotion in vitro , except latilagascene D, decreased IE-antigen expression of cytomegalovirus to prevent progression of tumor malignancy.

  16. MDRO - Multidrug-Resistant Organisms

    MedlinePlus

    ... Hazards (Lack of) PPE Slips/Trips/Falls Stress Tuberculosis Universal Precautions Workplace Violence Use of Medical Lasers ... PRSP - Penicillin-resistant Streptococcus pneumoniae Multi-drug resistant Tuberculosis (MDR) TB is covered in HealthCare Wide Hazards ...

  17. Multidrug-Resistant TB

    PubMed Central

    Cox, Helen; Coomans, Fons

    2016-01-01

    Abstract The right to enjoy the benefits of scientific progress (REBSP) is a little-known but potentially valuable right that can contribute to rights-based approaches to addressing multidrug-resistant TB (MDR-TB). We argue that better understanding of the REBSP may help to advance legal and civil society action for health rights. While the REBSP does not provide an individual entitlement to have a new drug developed for MDR-TB, it sets up entitlements to expect a state to establish a legislative and policy framework aimed at developing scientific capacity to address the most important health issues and at disseminating the outcomes of scientific research. By making scientific findings available and accessible, people can be enabled to claim the use of science for social benefits. Inasmuch as the market fails to address neglected diseases such as MDR-TB, the REBSP provides a potential counterbalance to frame a positive obligation on states to both marshal their own resources and to coordinate the actions of multiple other actors towards this goal, including non-state actors. While the latter do not hold the same level of accountability as states, the REBSP can still enable the recognition of obligations at a level of “soft law” responsibilities. PMID:27780997

  18. Multidrug Resistant Acinetobacter

    PubMed Central

    Manchanda, Vikas; Sanchaita, Sinha; Singh, NP

    2010-01-01

    Emergence and spread of Acinetobacter species, resistant to most of the available antimicrobial agents, is an area of great concern. It is now being frequently associated with healthcare associated infections. Literature was searched at PUBMED, Google Scholar, and Cochrane Library, using the terms ‘Acinetobacter Resistance, multidrug resistant (MDR), Antimicrobial Therapy, Outbreak, Colistin, Tigecycline, AmpC enzymes, and carbapenemases in various combinations. The terms such as MDR, Extensively Drug Resistant (XDR), and Pan Drug Resistant (PDR) have been used in published literature with varied definitions, leading to confusion in the correlation of data from various studies. In this review various mechanisms of resistance in the Acinetobacter species have been discussed. The review also probes upon the current therapeutic options, including combination therapies available to treat infections due to resistant Acinetobacter species in adults as well as children. There is an urgent need to enforce infection control measures and antimicrobial stewardship programs to prevent the further spread of these resistant Acinetobacter species and to delay the emergence of increased resistance in the bacteria. PMID:20927292

  19. Identification of Important Compounds Isolated from Natural Sources that Have Activity Against Multidrug-resistant Cancer Cell Lines: Effects on Proliferation, Apoptotic Mechanism and the Efflux Pump Responsible for Multi-resistance Phenotype.

    PubMed

    Amaral, Leonard; Spengler, Gabriella; Molnar, Joseph

    2016-11-01

    The focus of this mini-review is to identify non-toxic compounds isolated from natural sources (plants) that exhibit specific activity against efflux pumps of specific multidrug-resistant (MDR) cancer cell lines, inhibit proliferation of the MDR cancer cell lines and inhibit the activity of overexpressed efflux pumps of the MDR cancer cell line.

  20. Suppression of MAPK Signaling and Reversal of mTOR-Dependent MDR1-Associated Multidrug Resistance by 21α-Methylmelianodiol in Lung Cancer Cells

    PubMed Central

    Aldonza, Mark Borris Docdoc; Hong, Ji-Young; Bae, Song Yi; Song, Jayoung; Kim, Won Kyung; Oh, Jedo; Shin, Yoonho; Lee, Seung Ho; Lee, Sang Kook

    2015-01-01

    Lung cancer is the leading cause of cancer-related deaths worldwide and remains the most prevalent. Interplay between PI3K/AMPK/AKT and MAPK pathways is a crucial effector in lung cancer growth and progression. These signals transduction protein kinases serve as good therapeutic targets for non-small cell lung cancer (NSCLC) which comprises up to 90% of lung cancers. Here, we described whether 21α-Methylmelianodiol (21α-MMD), an active triterpenoid derivative of Poncirus trifoliate, can display anticancer properties by regulating these signals and modulate the occurrence of multidrug resistance in NSCLC cells. We found that 21α-MMD inhibited the growth and colony formation of lung cancer cells without affecting the normal lung cell phenotype. 21α-MMD also abrogated the metastatic activity of lung cancer cells through the inhibition of cell migration and invasion, and induced G0/G1 cell cycle arrest with increased intracellular ROS generation and loss of mitochondrial membrane integrity. 21α-MMD regulated the expressions of PI3K/AKT/AMPK and MAPK signaling which drove us to further evaluate its activity on multidrug resistance (MDR) in lung cancer cells by specifying on P-glycoprotein (P-gp)/MDR1-association. Employing the established paclitaxel-resistant A549 cells (A549-PacR), we further found that 21α-MMD induced a MDR reversal activity through the inhibition of P-gp/MDR1 expressions, function, and transcription with regained paclitaxel sensitivity which might dependently correlate to the regulation of PI3K/mTOR signaling pathway. Taken together, these findings demonstrate, for the first time, the mechanistic evaluation in vitro of 21α-MMD displaying growth-inhibiting potential with influence on MDR reversal in human lung cancer cells. PMID:26098947

  1. Cell-specific activity of cis-acting regulatory elements in the promoter of the mouse multidrug resistance gene mdr1.

    PubMed

    Raymond, M; Gros, P

    1990-11-01

    To define cis-acting elements implicated in transcriptional regulation of the mouse multidrug resistance gene mdr1, we have cloned and characterized the 5' end of the gene. Nucleotide sequence analysis identified TATA, GGGCGG, and CCAAT consensus sequence elements at positions -27, -47, and -83, respectively. The transcriptional activities of 5' deletion fragments from the promoter linked to a reporter gene were tested in mouse cell lines of different tissue origins shown to express different levels of endogenous mdr1 RNA. Sequences located between nucleotides -93 and +84 were able to confer basal promoter activity and cell specificity to the reporter gene. The addition to the basal promoter of sequences upstream of position -141 was found to up or down regulate the basal level of expression of the reporter gene in a cell-specific manner.

  2. Cytotoxicity of Endoperoxides from the Caribbean Sponge Plakortis halichondrioides towards Sensitive and Multidrug-Resistant Leukemia Cells: Acids vs. Esters Activity Evaluation

    PubMed Central

    Schirmeister, Tanja; Oli, Swarna; Wu, Hongmei; Della Sala, Gerardo; Costantino, Valeria; Seo, Ean-Jeong; Efferth, Thomas

    2017-01-01

    The 6-epimer of the plakortide H acid (1), along with the endoperoxides plakortide E (2), plakortin (3), and dihydroplakortin (4) have been isolated from a sample of the Caribbean sponge Plakortis halichondrioides. To perform a comparative study on the cytotoxicity towards the drug-sensitive leukemia CCRF-CEM cell line and its multi-drug resistant subline CEM/ADR5000, the acid of plakortin, namely plakortic acid (5), as well as the esters plakortide E methyl ester (6) and 6-epi-plakortide H (7) were synthesized by hydrolysis and Steglich esterification, respectively. The data obtained showed that the acids (1, 2, 5) exhibited potent cytotoxicity towards both cell lines, whereas the esters showed no activity (6, 7) or weaker activity (3, 4) compared to their corresponding acids. Plakortic acid (5) was the most promising derivative with half maximal inhibitory concentration (IC50) values of ca. 0.20 µM for both cell lines. PMID:28273803

  3. Binding and inhibition of drug transport proteins by heparin: a potential drug transporter modulator capable of reducing multidrug resistance in human cancer cells.

    PubMed

    Chen, Yunliang; Scully, Michael; Petralia, Gloria; Kakkar, Ajay

    2014-01-01

    A major problem in cancer treatment is the development of resistance to chemotherapeutic agents, multidrug resistance (MDR), associated with increased activity of transmembrane drug transporter proteins which impair cytotoxic treatment by rapidly removing the drugs from the targeted cells. Previously, it has been shown that heparin treatment of cancer patients undergoing chemotherapy increases survival. In order to determine whether heparin is capable reducing MDR and increasing the potency of chemotherapeutic drugs, the cytoxicity of a number of agents toward four cancer cell lines (a human enriched breast cancer stem cell line, two human breast cancer cell lines, MCF-7 and MDA-MB-231, and a human lung cancer cell line A549) was tested in the presence or absence of heparin. Results demonstrated that heparin increased the cytotoxicity of a range of chemotherapeutic agents. This effect was associated with the ability of heparin to bind to several of the drug transport proteins of the ABC and non ABC transporter systems. Among the ABC system, heparin treatment caused significant inhibition of the ATPase activity of ABCG2 and ABCC1, and of the efflux function observed as enhanced intracellular accumulation of specific substrates. Doxorubicin cytoxicity, which was enhanced by heparin treatment of MCF-7 cells, was found to be under the control of one of the major non-ABC transporter proteins, lung resistance protein (LRP). LRP was also shown to be a heparin-binding protein. These findings indicate that heparin has a potential role in the clinic as a drug transporter modulator to reduce multidrug resistance in cancer patients.

  4. The short-time treatment with curcumin sufficiently decreases cell viability, induces apoptosis and copper enhances these effects in multidrug-resistant K562/A02 cells.

    PubMed

    Lu, Jin-Jian; Cai, Yu-Jun; Ding, Jian

    2012-01-01

    The anti-cancer activities of curcumin (CUR), a polyphenol derived from the plant Curcuma longa, has been extensively studied. In the present study, we found that CUR displayed anti-multidrug-resistant (MDR) activity in K562/A02 cells. A short-time treatment with CUR sufficiently and equally induced DNA damage, decreased cell viability, and triggered apoptosis in parent K562 and MDR K562/A02 cells. The short-time treatment with CUR also caused decrease of pro-caspase 3 in both cell lines and decrease of pro-caspase 9, increase of PARP cleavage and the ratio of Bax/Bcl-xL in MDR K562/A02 cells. Further experiment revealed that CUR was capable of down-regulating P-glycoprotein in MDR K562/A02 cells. Moreover, we observed that Cu(2+) enhanced CUR-mediated apoptosis which was blocked by antioxidants N-acetyl-cysteine and catalase. In summary, the short-time treatment with CUR sufficiently induced DNA damage, decreased cell viability and triggered apoptosis in MDR K562/A02 cells and Cu(2+) enhanced CUR-mediated apoptosis which due to reactive oxygen species generation.

  5. Purine analogs sensitize the multidrug resistant cell line (NCI-H460/R) to doxorubicin and stimulate the cell growth inhibitory effect of verapamil.

    PubMed

    Pesić, Milica; Podolski, Ana; Rakić, Ljubisa; Ruzdijić, Sabera

    2010-08-01

    The resistant cell line NCI-H460/R and its counterpart NCI-H460 were used to investigate the ability of purine analogs to overcome multidrug resistance (MDR) that seriously limit the efficacy of lung cancer regimens with chemotherapeutic agents. Two purine analogs, sulfinosine (SF) and 8-Cl-cAMP, exerted dose-dependent effects on cell growth in both parental and resistant cell lines. They significantly decreased mdr1 expression in NCI-H460/R cells. Low concentrations (1 microM) of SF and 8-Cl-cAMP in combination with doxorubicin (DOX) exerted synergistic growth inhibition in both cell lines. Pretreatment with SF and 8-Cl-cAMP improved the sensitivity to DOX more than verapamil (VER), the standard modulator of MDR. The increased accumulation of DOX observed after the treatment with SF and 8-Cl-cAMP was consistent with the results obtained with VER. VER stimulated the effect of 8-Cl-cAMP on DOX cytotoxicity and mdr1 expression. Combinations of either SF or 8-Cl-cAMP with VER at clinically acceptable concentrations exhibited synergistic effects on cell growth inhibition in the resistant cell line. SF and 8-Cl-cAMP modulated MDR in NCI-H460/R cells, especially when applied before DOX administration. This feature, together with their ability to reverse MDR, renders the purine analogs (in combination with VER) as potential candidates for improving the clinical activity of existing lung cancer therapeutics.

  6. Multidrug Resistance: Physiological Principles and Nanomedical Solutions

    PubMed Central

    Storm, Gert; Kiessling, Fabian; Lammers, Twan

    2014-01-01

    Multidrug (MDR) resistance is a pathophysiological phenomenon employed by cancer cells which limits the prolonged and effective use of chemotherapeutic agents. MDR is primarily based on the over-expression of drug efflux pumps in the cellular membrane. Prominent examples of such efflux pumps, which belong to the ATP-binding cassette (ABC) superfamily of proteins, are Pgp (P-glycoprotein) and MRP (multidrug resistance-associated protein), nowadays officially known as ABCB1 and ABCC1. Over the years, several strategies have been evaluated to overcome MDR, based not only on the use of low-molecular-weight MDR modulators, but also on the implementation of 1-100(0) nm-sized drug delivery systems. In the present manuscript, after introducing the most important physiological principles of MDR, we summarize prototypic nanomedical strategies to overcome multidrug resistance, including the use of carrier materials with intrinsic anti-MDR properties, the use of nanomedicines to modify the mode of cellular uptake, and the co-formulation of chemotherapeutic drugs together with low- and high-molecular-weight MDR inhibitors within a single drug delivery system. While certain challenges still need to be overcome before such constructs and concepts can be widely applied in the clinic, the insights obtained and the progress made strongly suggest that nanomedicine formulations hold significant potential for improving the treatment of multidrug-resistant malignancies. PMID:24120954

  7. The role of fnx1, a fission yeast multidrug resistance protein, in the transition of cells to a quiescent G0 state.

    PubMed

    Dimitrov, K; Sazer, S

    1998-09-01

    Most microorganisms live in conditions of nutrient limitation in their natural habitats. When exposed to these conditions they respond with physiological and morphological changes that enable them to survive. To obtain insights into the molecular mechanisms of this response a systematic genetic screen was performed to identify genes that when overexpressed can induce a starvation-like response in the yeast species Schizosaccharomyces pombe. One gene that meets these criteria, fnx1(+), induces, transcriptionally correlates with, and is required for the entry into the quiescent G0 state that is normally induced by nitrogen starvation. fnx1(+) encodes a protein with sequence similarity to the proton-driven plasma membrane transporters from the multidrug resistance group of the major facilitator superfamily of proteins. We propose that fnx1(+) plays a role in the entry into G0, possibly by facilitating the release of a signaling substance into the environment as a means of cell-to-cell communication.

  8. The synthetic ajoene analog SPA3015 induces apoptotic cell death through crosstalk between NF-κB and PPARγ in multidrug-resistant cancer cells.

    PubMed

    Hwang, Jee Won; Cho, Hyewon; Lee, Jae Yeon; Jeon, Youngsic; Kim, Su-Nam; Lee, Sang Jin; Bae, Gyu-Un; Yoon, Sungpil; Jeon, Raok; Kim, Yong Kee

    2016-10-01

    Multidrug resistance (MDR) caused by P-glycoprotein (P-gp) overexpression impedes successful cancer chemotherapy. In this study, we investigated the anticancer effects of SPA3015, a synthetic ajoene analog, in P-gp-overexpressing MDR cancer cells (KBV20C and MES-SA/DX5). Treatment with SPA3015 caused a dramatic decrease in the cell viabilities of both KBV20C and MES-SA/DX5 cells. This decrease was accompanied by apoptotic cell death without affecting the expression level or drug efflux function of P-gp. SPA3015 selectively suppressed NF-κB reporter gene activity, which led to decreased expression of NF-κB target genes such as CIAP1, CIAP2, XIAP, and Bcl-XL. Surprisingly, nuclear localization and DNA binding affinity of the p65 subunit were not affected by SPA3015, suggesting that SPA3015 inhibits the transcriptional activity of NF-κB at the nucleus. Indeed, SPA3015 treatment led to an increase in the physical interaction of p65 with PPARγ, which resulted in the inhibition of NF-κB activity. Our findings support the hypothesis that SPA3015 inhibits NF-κB transcriptional activity by facilitating the physical interaction of the p65 subunit and PPARγ, which leads to apoptotic cell death in MDR cancer cells.

  9. Overexpression of the Gene Encoding the Multidrug Resistance-Associated Protein Results in Increased ATP-Dependent Glutathione S-Conjugate Transport

    NASA Astrophysics Data System (ADS)

    Muller, Michael; Meijer, Coby; Zaman, Guido J. R.; Borst, Piet; Scheper, Rik J.; Mulder, Nanno H.; de Vries, Elisabeth G. E.; Jansen, Peter L. M.

    1994-12-01

    The multidrug resistance-associated protein (MRP) is a 180- to 195-kDa glycoprotein associated with multidrug resistance of human tumor cells. MRP is mainly located in the plasma membrane and it confers resistance by exporting natural product drugs out of the cell. Here we demonstrate that overexpression of the MRP gene in human cancer cells increases the ATP-dependent glutathione S-conjugate carrier activity in plasma membrane vesicles isolated from these cells. The glutathione S-conjugate export carrier is known to mediate excretion of bivalent anionic conjugates from mammalian cells and is thought to play a role in the elimination of conjugated xenobiotics. Our results suggest that MRP can cause multidrug resistance by promoting the export of drug modification products from cells and they shed light on the reported link between drug resistance and cellular glutathione and glutathione S-transferase levels.

  10. NANOPREPARATIONS TO OVERCOME MULTIDRUG RESISTANCE IN CANCER

    PubMed Central

    Patel, Niravkumar R.; Pattni, Bhushan S.; Abouzeid, Abraham H.; Torchilin, Vladimir P.

    2013-01-01

    Multidrug resistance is the most widely exploited phenomenon by which cancer eludes chemotherapy. Broad variety of factors, ranging from the cellular ones, such as over-expression of efflux transporters, defective apoptotic machineries, and altered molecular targets, to the physiological factors such as higher interstitial fluid pressure, low extracellular pH, and formation of irregular tumor vasculature are responsible for multidrug resistance. A combination of various undesirable factors associated with biological surroundings together with poor solubility and instability of many potential therapeutic small & large molecules within the biological systems and systemic toxicity of chemotherapeutic agents has necessitated the need for nano-preparations to optimize drug delivery. The physiology of solid tumors presents numerous challenges for successful therapy. However, it also offers unique opportunities for the use of nanotechnology. Nanoparticles, up to 400 nm in size, have shown great promise for carrying, protecting and delivering potential therapeutic molecules with diverse physiological properties. In this review, various factors responsible for the MDR and the use of nanotechnology to overcome the MDR, the use of spheroid culture as well as the current technique of producing micro tumor tissues in vitro are discussed in detail. PMID:23973912

  11. Synergistic effects of the purine analog sulfinosine and curcumin on the multidrug resistant human non-small cell lung carcinoma cell line (NCI-H460/R).

    PubMed

    Andjelkovic, Tijana; Pesic, Milica; Bankovic, Jasna; Tanic, Nikola; Markovic, Ivanka D; Ruzdijic, Sabera

    2008-07-01

    Multidrug resistance (MDR) is the main obstacle to a successful chemotherapy of lung cancer. We tested the potential of sulfinosine and curcumin, alone and in combination, for modulating MDR in the human resistant, non-small cell lung carcinoma cell line (NCI-H460/R). First, we determined the mutational status of the p53 gene in NCI-H460/R cells by PCR-SSCP and DNA sequencing and identified mutations which could at least partially contribute to the development of the MDR phenotype. The effects of sulfinosine and curcumin were studied, both separately and in combination, at the level of cytotoxicity, cell cycle distribution and gene expression. Sulfinosine displayed dose-dependent growth inhibition in both resistant and control sensitive cell lines, whereas curcumin considerably inhibited their growth only at relatively high doses. When sulfinosine was combined with a low dose of curcumin the drugs exerted a synergistic cytotoxic effect in NCI-H460/R cells. The expression of MDR-related genes mdr1, gst-pi and topo IIalpha, was altered by sulfinosine and curcumin. The most pronounced effect was observed when the agents were applied together. Sulfinosine and curcumin caused perturbations in cell cycle distribution in the NCI-H460/R cell line. The combination of the two drugs induced a more pronounced cell cycle arrest in S and G(2)/M in NCI-H460/R cells. Our results show that sulfinosine and curcumin overcome MDR in non-small cell lung carcinoma cell line (NSCLC), especially in combination despite the presence of a mutated p53 gene.

  12. Pyrazine, 2-ethylpyridine, and 3-ethylpyridine are cigarette smoke components that alter the growth of normal and malignant human lung cells, and play a role in multidrug resistance development.

    PubMed

    Liu, Min; Poo, Wak-Kim; Lin, Yu-Ling

    2015-02-01

    Lung cancer is one of the few human diseases for which the primary etiological agent, cigarette smoke (CS), has been described; however, the precise role of individual cigarette smoke toxicant in tumor development and progression remains to be elusive. The purpose of this study was to assess in vitro the effects of previously identified cigarette smoke components, pyrazine, 2-ethylpyridine, and 3-ethylpyridine, on non-tumorigenic (MRC5) and adenocarcinomic (A549) human lung cell lines. Our data showed that the administration of three cigarette smoke components in combination perturbed the proliferation of both normal and adenocarcinomic cells. Study of malignant cells revealed that CS components were cytotoxic at high concentration (10(-6) M) and stimulatory in a dose-dependent manner at lower concentrations (10(-8) M to 10(-10) M). This adverse effect was enhanced when adenocarcinomic cells were maintained in hypoxia resembling intratumoral environment. Furthermore, exposure to pyrazine, 2-ethylpyridine, and 3-ethylpyridine induced oxidative stress in both normal and malignant cells. Finally, assessment of P-gp activity revealed that multidrug resistance was induced in CS component exposed adenocarcinomic lung cells and the induction was augmented in hypoxia. Taken together, pyrazine, 2-ethylpyridine, and 3-ethylpyridine adversely altered both normal and diseased lung cells in vitro and data collected from this study may help lung cancer patients to understand the importance of quitting smoking during lung cancer treatment.

  13. Combined activity of interleukin-1 alpha or TNF-alpha and doxorubicin on multidrug resistant cell lines: evidence that TNF and DXR have synergistic antitumor and differentiation-inducing effects.

    PubMed

    Borsellino, N; Crescimanno, M; Flandina, C; Flugy, A; D'Alessandro, N

    1994-01-01

    We report on the antiproliferative effects that interleukin-1 alpha (IL-1) or TNF-alpha (TNF) in combination with doxorubicin (DXR) exert on DXR-sensitive (B16 melanoma, Friend, K562 and CCRF/CEM leukemias) and -resistant (B16-DXR, FLC-DXR, K562-DXR) cell lines in vitro. Multidrug resistance (MDR) of the latter lines entails cross-resistance to vincristine and overexpression of P-glycoprotein. Il-1 showed only a very marginal growth inhibitory activity and the effects of its combination with DXR were essentially additive in all the cell lines, except in chemosensitive B16, where a slight synergism occurred. TNF demonstrated greater antiproliferative activity in the MDR B16 and Friend tumors than in their parent variants. The combination of TNF and DXR produced synergistic growth inhibition in B16, K562 and, particularly, also in the MDR sublines of these two tumors. In addition, TNF and DXR induced synergistically erythroid differentiation in K562 and multidirectional differentiation in K562-DXR. The synergism was critically schedule-dependent in that it was achieved only when DXR application preceded or was simultaneous with that of TNF. Finally, TNF did not modify drug accumulation and retention in the cells. Our present findings stress especially the fact that DXR and TNF may exert useful antitumor synergism even in MDR lines; however, it is not likely that their interaction will occur at the specific MDR process level.

  14. Vitamin E derivative-based multifunctional nanoemulsions for overcoming multidrug resistance in cancer.

    PubMed

    Zheng, Nannan; Gao, Yanan; Ji, Hongyu; Wu, Linhua; Qi, Xuejing; Liu, Xiaona; Tang, Jingling

    2016-08-01

    The multidrug resistance (MDR), including intrinsic and acquired multidrug resistance, is a major problem in tumor chemotherapy. Here, we proposed a strategy for modulating intrinsic and/or acquired multidrug resistance by altering the levels of Bax and Bcl-2 expression and inhibiting the transport function of P-gp, increasing the intracellular concentration of its substrate anticancer drugs. Vitamin E derivative-based nanoemulsions containing paclitaxel (MNEs-PTX) were fabricated in this study, and in vitro anticancer efficacy of the nanoemulsion system was evaluated in the paclitaxel-resistant human ovarian carcinoma cell line A2780/Taxol. The MNEs-PTX exhibited a remarkably enhanced antiproliferation effect on A2780/Taxol cells than free paclitaxel (PTX) (p < 0.01). Compared with that in the Taxol group, MNEs-PTX further decreased mitochondrial potential. Vitamin E derivative-based multifunctional nanoemulsion (MNEs) obviously increased intracellular accumulation of rhodamine 123 (P-gp substrate). Overexpression of Bcl-2 is generally associated with tumor drug resistance, we found that MNEs could reduce Bcl-2 protein level and increase Bax protein level. Taken together, our findings suggest that anticancer drugs associated with MNEs could play a role in the development of MDR in cancers.

  15. Starvation, detoxification, and multidrug resistance in cancer therapy

    PubMed Central

    Lee, Changhan; Raffaghello, Lizzia; Longo, Valter D.

    2013-01-01

    The selection of chemotherapy drugs is based on the cytotoxicity to specific tumor cell types and the relatively low toxicity to normal cells and tissues. However, the toxicity to normal cells poses a major clinical challenge, particularly when malignant cells have acquired resistance to chemotherapy. This drug resistance of cancer cells results from multiple factors including individual variation, genetic heterogeneity within a tumor, and cellular evolution. Much progress in the understanding of tumor cell resistance has been made in the past 35 years, owing to milestone discoveries such as the identification and characterization of ABC transporters. Nonetheless, the complexity of the genetic and epigenetic rewiring of cancer cells makes drug resistance an equally complex phenomenon that is difficult to overcome. In this review, we discuss how the remarkable changes in the levels of glucose, IGF-I, IGFBP-1 and in other proteins caused by fasting have the potential to improve the efficacy of chemotherapy against tumors by protecting normal cells and tissues and possibly by diminishing multidrug resistance in malignant cells. PMID:22391012

  16. Pien Tze Huang Overcomes Multidrug Resistance and Epithelial-Mesenchymal Transition in Human Colorectal Carcinoma Cells via Suppression of TGF-β Pathway

    PubMed Central

    Shen, Aling; Chen, Hongwei; Chen, Youqin; Lin, Wei; Liu, Liya; Sferra, Thomas J.; Peng, Jun

    2014-01-01

    The traditional Chinese medicine formula Pien Tze Huang (PZH) has long been used as a folk remedy for cancer. To elucidate the mode of action of PZH against cancer, in the present study we used a 5-FU resistant human colorectal carcinoma cell line (HCT-8/5-FU) to evaluate the effects of PZH on multidrug resistance (MDR) and epithelial-mesenchymal transition (EMT) as well as the activation of TGF-β pathway. We found that PZH dose-dependently inhibited the viability of HCT-8/5-FU cells which were insensitive to treatment of 5-FU and ADM, demonstrating the ability of PZH to overcome chemoresistance. Furthermore, PZH increased the intercellular accumulation of Rhodamine-123 and downregulated the expression of ABCG2 in HCT-8/5-FU cells. In addition, drug resistance induced the process of EMT in HCT-8 cells as evidenced by EMT-related morphological changes and alteration in the expression of EMT-regulatory factors, which however was neutralized by PZH treatment. Moreover, PZH inhibited MDR/EMT-enhanced migration and invasion capabilities of HCT-8 cells in a dose-dependent manner and suppressed MDR-induced activation of TGF-β signaling in HCT-8/5-FU cells. Taken together, our study suggests that PZH can effectively overcome MDR and inhibit EMT in human colorectal carcinoma cells via suppression of the TGF-β pathway. PMID:25505925

  17. Pien Tze Huang Overcomes Multidrug Resistance and Epithelial-Mesenchymal Transition in Human Colorectal Carcinoma Cells via Suppression of TGF-β Pathway.

    PubMed

    Shen, Aling; Chen, Hongwei; Chen, Youqin; Lin, Jiumao; Lin, Wei; Liu, Liya; Sferra, Thomas J; Peng, Jun

    2014-01-01

    The traditional Chinese medicine formula Pien Tze Huang (PZH) has long been used as a folk remedy for cancer. To elucidate the mode of action of PZH against cancer, in the present study we used a 5-FU resistant human colorectal carcinoma cell line (HCT-8/5-FU) to evaluate the effects of PZH on multidrug resistance (MDR) and epithelial-mesenchymal transition (EMT) as well as the activation of TGF-β pathway. We found that PZH dose-dependently inhibited the viability of HCT-8/5-FU cells which were insensitive to treatment of 5-FU and ADM, demonstrating the ability of PZH to overcome chemoresistance. Furthermore, PZH increased the intercellular accumulation of Rhodamine-123 and downregulated the expression of ABCG2 in HCT-8/5-FU cells. In addition, drug resistance induced the process of EMT in HCT-8 cells as evidenced by EMT-related morphological changes and alteration in the expression of EMT-regulatory factors, which however was neutralized by PZH treatment. Moreover, PZH inhibited MDR/EMT-enhanced migration and invasion capabilities of HCT-8 cells in a dose-dependent manner and suppressed MDR-induced activation of TGF-β signaling in HCT-8/5-FU cells. Taken together, our study suggests that PZH can effectively overcome MDR and inhibit EMT in human colorectal carcinoma cells via suppression of the TGF-β pathway.

  18. Acquisition of multidrug resistance by L1210 leukemia cells decreases their tumorigenicity and enhances their susceptibility to the host immune response.

    PubMed

    Martín-Orozco, Elena; Ferragut, José Antonio; Garcia-Peñarrubia, Pilar; Ferrer-Montiel, Antonio

    2005-04-01

    The use of antineoplastic drugs for cancer treatment is frequently associated with the acquisition of a multidrug-resistant (MDR) phenotype that renders tumoural cells insensitive to antineoplastics. It remains elusive whether the acquisition of the MDR phenotype alters immunological parameters that could influence the cell sensitivity to an eventual host immune response. We report that immunisation of syngeneic mice with gamma-irradiated L1210S (parental line) and L1210R (MDR phenotype) cells results in a significant rejection of subsequently implanted L1210R-based tumours, but not of the L1210S ones. Notably, L1210R tumours display a twofold reduction in vivo proliferative capacity and are less aggressive in terms of mouse survival than their sensitive counterparts. Also, analysis of surface expression of molecules involved in antigen presentation and cytokine activity revealed a slight increase in IFN-gamma receptor expression, a decrease of Fas molecule, and a fourfold up-regulation of MHC class I molecules in L1210R cells. Nonetheless, both cell lines were able to induce a cytotoxic response in syngeneic mice and were equally susceptible to cytotoxicity by splenic cells. Together, these findings indicate that acquisition of drug resistance by L1210 cells is accompanied by pleiotropic changes that result in reduced tumour proliferative capacity and tumorigenicity in syngeneic mice. Hence, immunological studies of MDR tumours may assist in the design of specific therapeutic strategies that complement current chemotherapy treatments.

  19. Inhibition of human 67-kDa laminin receptor sensitizes multidrug resistance colon cancer cell line SW480 for apoptosis induction.

    PubMed

    Lu, Chun-Lei; Xu, Jian; Yao, Hao-Jie; Luo, Kun-Lun; Li, Jie-Ming; Wu, Tao; Wu, Guo-Zhong

    2016-01-01

    The adhesion mediated drug resistance in cancer cells resulted from adhesion of the extracellular matrix is a major cause for multidrug resistance (MDR) and leads chemotherapeutic failure for colon cancer. In this study, we explored the role of 67-kDa laminin receptor (67LR) in chemotherapeutic drug resistance in colon cancer cells. SiRNA-mediated knockdown of 67LR decreased the cell adhesion when laminins were applied. Moreover, 67LR knockdown increased the expression of pro-apoptotic gene Bax but inhibited the expression of anti-apoptotic gene Bcl-2. Enhanced apoptosis was observed in 67LR siRNA-transfected SW480 cell when the cell was treated with doxorubicin for apoptosis induction. Furthermore, MTT assay revealed that the IC50 of chemotherapeutic toward SW480 cell adhesion to laminins was reduced after 67LR knockdown, indicating there was a significant increase of drug sensitivity in SW480 cell. In conclusion, our study demonstrated that 67LR plays a considerable role in the development of colon cancer MDR.

  20. N,N-Dimethyl phytosphingosine sensitizes HL-60/MX2, a multidrug-resistant variant of HL-60 cells, to doxorubicin-induced cytotoxicity through ROS-mediated release of cytochrome c and AIF.

    PubMed

    Kim, Byeong Mo; Choi, Yun Jung; Lee, Yong Heon; Joe, Young Ae; Hong, Sung Hee

    2010-08-01

    Doxorubicin (Dox) is widely used to treat a variety of tumors. However, resistance to this drug is common, making successful treatment more difficult. Previously, we introduced a novel phytosphingosine derivative, N,N-dimethyl phytosphingosine (DMPS), as a potent anticancer therapeutic agent in human leukemia cells. This study was performed to investigate whether DMPS can sensitize HL-60/MX2, a multidrug-resistant variant of HL-60, to Dox-induced apoptosis. Low concentrations of DMPS sensitized HL-60/MX2 cells to Dox-induced apoptosis. Combined Dox + DMPS treatment-induced apoptosis was accompanied by the activation of caspase-8 and caspase-3 as well as PARP cleavage. Cytochrome c and AIF release were also observed in Dox + DMPS-treated HL60/MX2 cells. Pretreatment with z-VAD-fmk markedly prevented caspase-3 activation and moderately suppressed apoptosis, suggesting that Dox + DMPS-induced apoptosis is somewhat (not completely) dependent on caspase. Cytochrome c and AIF release were not affected by pretreatment with z-VAD-fmk. The ROS scavenger NAC efficiently suppressed not only ROS generation, but also caspase-3-mediated PARP cleavage, apoptosis, and release of cytochrome c and AIF, indicating a role of ROS in combined Dox + DMPS treatment-induced apoptotic death signaling. Taken together, these observations suggest that DMPS may be used as a therapeutic agent for overcoming drug-resistance in cancer cells by enhancing drug-induced apoptosis.

  1. Salinomycin enhances doxorubicin-induced cytotoxicity in multidrug resistant MCF-7/MDR human breast cancer cells via decreased efflux of doxorubicin.

    PubMed

    Kim, Kwang-Youn; Kim, Sang-Hun; Yu, Sun-Nyoung; Park, Suel-Ki; Choi, Hyeun-Deok; Yu, Hak-Sun; Ji, Jae-Hoon; Seo, Young-Kyo; Ahn, Soon-Cheol

    2015-08-01

    Salinomycin is a monocarboxylic polyether antibiotic, which is widely used as an anticoccidial agent. The anticancer property of salinomycin has been recognized and is based on its ability to induce apoptosis in human multidrug resistance (MDR). The present study investigated whether salinomycin reverses MDR towards chemotherapeutic agents in doxorubicin-resistant MCF-7/MDR human breast cancer cells. The results demonstrated that doxorubicin-mediated cytotoxicity was significantly enhanced by salinomycin in the MCF-7/MDR cells, and this occurred in a dose-dependent manner. This finding was consistent with subsequent observations made under a confocal microscope, in which the doxorubicin fluorescence signals of the salinomycin-treated cells were higher compared with the cells treated with doxorubicin alone. In addition, flow cytometric analysis revealed that salinomycin significantly increased the net cellular uptake and decreased the efflux of doxorubicin. The expression levels of MDR-1 and MRP-1 were not altered at either the mRNA or protein levels in the cells treated with salinomycin. These results indicated that salinomycin was mediated by its ability to increase the uptake and decrease the efflux of doxorubicin in MCF-7/MDR cells. Salinomycin reversed the resistance of doxorubicin, suggesting that chemotherapy in combination with salinomycin may benefit MDR cancer therapy.

  2. Apoptotic effect of a novel kefir product, PFT, on multidrug-resistant myeloid leukemia cells via a hole-piercing mechanism

    PubMed Central

    GHONEUM, MAMDOOH; GIMZEWSKI, JAMES

    2014-01-01

    We examined the apoptotic effect of a novel Probiotics Fermentation Technology (PFT) kefir grain product; PFT is a natural mixture composed primarily of Lactobacillus kefiri P-IF, a specific strain of L. kefiri with unique growth characteristics. The aim of this study was to examine the apoptotic effect of PFT on human multidrug-resistant (MDR) myeloid leukemia (HL60/AR) cells in vitro and explore the mechanistic approach underlying its effect. HL60/AR cells were cultured with PFT (0.6–5.0 mg/ml) for 3 days. The apoptotic effect of PFT was assessed through examination of percent apoptosis, caspase 3 activation, Bcl-2 expression levels and changes in mitochondrial membrane potential (MMP). PFT induced apoptosis in HL60/AR cells in a dose-dependent manner which was maximal at 67.5% for 5 mg/ml. Induction of apoptosis was associated with activation of caspase 3, decreased expression of Bcl-2 and decreased polarization of MMP. In addition, PFT showed a unique characteristic of piercing holes in HL60/AR cells, as indicated by AFM studies. This hole induction may be responsible for the apoptotic effect on cancer cells. These results suggest that PFT may act as a potential therapy for the treatment of MDR leukemia. PMID:24430613

  3. Thio and Seleno Rhodamine Derivatives as Reversal Agents of Multidrug Resistance in Breast Cancer

    DTIC Science & Technology

    2005-09-01

    rhodamine-induced photosensitized inhibition of Pgp results in greater chemo- sensitivity and/or enhanced phototoxicity . The completed work demonstrates...that substituent effects among the various rhodamine analogues impact their phototoxicity towards either chemosensitive AUXB1 cells or multidrug...for the photosensitizers in the multidrug-resistant CRIR12 cells. 15. SUBJECT TERMS Photodynamic therapy , photosensitizers, multidrug resistance, P

  4. Multidrug resistance P-glycoprotein dampens SR-BI cholesteryl ester uptake from high density lipoproteins in human leukemia cells

    PubMed Central

    Spolitu, Stefano; Uda, Sabrina; Deligia, Stefania; Frau, Alessandra; Collu, Maria; Angius, Fabrizio; Batetta, Barbara

    2016-01-01

    Tumor cells are characterised by a high content of cholesterol esters (CEs), while tumor-bearing patients show low levels of high-density lipoproteins (HDLs). The origin and significance of high CE levels in cancer cell biology has not been completely clarified. Recent evidence that lymphoblastic cells selectively acquire exogenous CE from HDL via the scavenger receptor SR-BI has drawn attention to the additional membrane proteins involved in this pathway. P-glycopotein-MDR1 (P-gp) is a product of the MDR1 gene and confers resistance to antitumor drugs. Its possible role in plasma membrane cholesterol trafficking and CE metabolism has been suggested. In the present study this aspect was investigated in a lymphoblastic cell line selected for MDR1 resistance. CEM were made resistant by stepwise exposure to low (LR) and high (HR) doses of vincristine (VCR). P-gp activity (3H-vinblastine), CE content, CE and triglycerides (TG) synthesis (14C-oleate), neutral lipids and Dil-HDL uptake (fluorescence), SR-BI, ABCA1 and P-gp protein expression (western blotting) were determined. To better evaluate the relationship between CE metabolism and P-gp activity, the ACAT inhibitor Sandoz-58035 and the P-gp inhibitors progesterone, cyclosporine and verapamil were used. CE content and synthesis were similar in the parental and resistant cells. However, in the latter population, SR-BI protein expression increased, whereas CE-HDL uptake decreased. These changes correlated with the degree of VCR-resistance. As well as reverting MDR1-resistance, the inhibitors of P-gp activity induced the CE-HDL/SR-BI pathway by reactivating membrane cholesterol trafficking. Indeed, CE-HDL uptake, SRBI expression and CE content increased, whereas there was a decrease in cholesterol esterification. These results demonstrated that P-gp overexpression impairs anticancer drug uptake as well as the SR-BI mediated selective CE-HDL uptake. This suggests that these membrane proteins act in an opposite manner on

  5. Green Tea Catechin-Based Complex Micelles Combined with Doxorubicin to Overcome Cardiotoxicity and Multidrug Resistance

    PubMed Central

    Cheng, Tangjian; Liu, Jinjian; Ren, Jie; Huang, Fan; Ou, Hanlin; Ding, Yuxun; Zhang, Yumin; Ma, Rujiang; An, Yingli; Liu, Jianfeng; Shi, Linqi

    2016-01-01

    Chemotherapy for cancer treatment has been demonstrated to cause some side effects on healthy tissues and multidrug resistance of the tumor cells, which greatly limits therapeutic efficacy. To address these limitations and achieve better therapeutic efficacy, combination therapy based on nanoparticle platforms provides a promising approach through delivering different agents simultaneously to the same destination with synergistic effect. In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)-Epigallocatechin-3-O-gallate (EGCG) was constructed through electrostatic interaction and phenylboronic acid-catechol interaction between poly(ethylene glycol)-block-poly(lysine-co-lysine-phenylboronic acid) (PEG-PLys/PBA) and EGCG. DOX was co-loaded in the PIC micelles through π-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction endowed the PIC micelles with high stability under physiological condition. Moreover, acid cleavability of phenylboronic acid-catechol interaction in the micelle core has significant benefits for delivering EGCG and DOX to same destination with synergistic effects. In addition, benefiting from the oxygen free radicals scavenging activity of EGCG, combination therapy with EGCG and DOX in the micelle core could protect the cardiomyocytes from DOX-mediated cardiotoxicity according to the histopathologic analysis of hearts. Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse multidrug resistance of cancer cells. These results suggested that EGCG based PIC micelles could effectively overcome DOX induced cardiotoxicity and multidrug resistance. PMID:27375779

  6. Discovery of 14-3-3 protein-protein interaction inhibitors that sensitize multidrug-resistant cancer cells to doxorubicin and the Akt inhibitor GSK690693.

    PubMed

    Mori, Mattia; Vignaroli, Giulia; Cau, Ylenia; Dinić, Jelena; Hill, Richard; Rossi, Matteo; Colecchia, David; Pešić, Milica; Link, Wolfgang; Chiariello, Mario; Ottmann, Christian; Botta, Maurizio

    2014-05-01

    14-3-3 is a family of highly conserved adapter proteins that is attracting much interest among medicinal chemists. Small-molecule inhibitors of 14-3-3 protein-protein interactions (PPIs) are in high demand, both as tools to increase our understanding of 14-3-3 actions in human diseases and as leads to develop innovative therapeutic agents. Herein we present the discovery of novel 14-3-3 PPI inhibitors through a multidisciplinary strategy combining molecular modeling, organic synthesis, image-based high-content analysis of reporter cells, and in vitro assays using cancer cells. Notably, the two most active compounds promoted the translocation of c-Abl and FOXO pro-apoptotic factors into the nucleus and sensitized multidrug-resistant cancer cells to apoptotic inducers such as doxorubicin and the pan-Akt inhibitor GSK690693, thus becoming valuable lead candidates for further optimization. Our results emphasize the possible role of 14-3-3 PPI inhibitors in anticancer combination therapies.

  7. Targeting Multidrug-resistant Staphylococci with an anti-rpoA Peptide Nucleic Acid Conjugated to the HIV-1 TAT Cell Penetrating Peptide

    PubMed Central

    Abushahba, Mostafa FN; Mohammad, Haroon; Seleem, Mohamed N

    2016-01-01

    Staphylococcus aureus infections present a serious challenge to healthcare practitioners due to the emergence of resistance to numerous conventional antibiotics. Due to their unique mode of action, peptide nucleic acids are novel alternatives to traditional antibiotics to tackle the issue of bacterial multidrug resistance. In this study, we designed a peptide nucleic acid covalently conjugated to the HIV-TAT cell penetrating peptide (GRKKKRRQRRRYK) in order to target the RNA polymerase α subunit gene (rpoA) required for bacterial genes transcription. We explored the antimicrobial activity of the anti-rpoA construct (peptide nucleic acid-TAT) against methicillin-resistant S. aureus, vancomycin-intermediate S. aureus, vancomycin-resistant S. aureus, linezolid-resistant S. aureus, and methicillin-resistant S. epidermidis in pure culture, infected mammalian cell culture, and in an in vivo Caenorhabditis elegans infection model. The anti-rpoA construct led to a concentration-dependent inhibition of bacterial growth (at micromolar concentrations) in vitro and in both infected cell culture and in vivo in C. elegans. Moreover, rpoA gene silencing resulted in suppression of its message as well as reduced expression of two important methicillin-resistant S. aureus USA300 toxins (α-hemolysin and Panton-Valentine leukocidin). This study confirms that rpoA gene is a potential target for development of novel antisense therapeutics to treat infections caused by methicillin-resistant S. aureus. PMID:27434684

  8. Mitochondria of a human multidrug-resistant hepatocellular carcinoma cell line constitutively express inducible nitric oxide synthase in the inner membrane.

    PubMed

    Fantappiè, Ornella; Sassoli, Chiara; Tani, Alessia; Nosi, Daniele; Marchetti, Serena; Formigli, Lucia; Mazzanti, Roberto

    2015-06-01

    Mitochondria play a crucial role in pathways of stress conditions. They can be transported from one cell to another, bringing their features to the cell where they are transported. It has been shown in cancer cells overexpressing multidrug resistance (MDR) that mitochondria express proteins involved in drug resistance such as P-glycoprotein (P-gp), breast cancer resistant protein and multiple resistance protein-1. The MDR phenotype is associated with the constitutive expression of COX-2 and iNOS, whereas celecoxib, a specific inhibitor of COX-2 activity, reverses drug resistance of MDR cells by releasing cytochrome c from mitochondria. It is possible that COX-2 and iNOS are also expressed in mitochondria of cancer cells overexpressing the MDR phenotype. This study involved experiments using the human HCC PLC/PRF/5 cell line with and without MDR phenotype and melanoma A375 cells that do not express the MDR1 phenotype but they do iNOS. Western blot analysis, confocal immunofluorescence and immune electron microscopy showed that iNOS is localized in mitochondria of MDR1-positive cells, whereas COX-2 is not. Low and moderate concentrations of celecoxib modulate the expression of iNOS and P-gp in mitochondria of MDR cancer cells independently from inhibition of COX-2 activity. However, A375 cells that express iNOS also in mitochondria, were not MDR1 positive. In conclusion, iNOS can be localized in mitochondria of HCC cells overexpressing MDR1 phenotype, however this phenomenon appears independent from the MDR1 phenotype occurrence. The presence of iNOS in mitochondria of human HCC cells phenotype probably concurs to a more aggressive behaviour of cancer cells.

  9. Development of sulfasalazine resistance in human T cells induces expression of the multidrug resistance transporter ABCG2 (BCRP) and augmented production of TNFα

    PubMed Central

    van der Heijden, J; de Jong, M C; Dijkmans, B; Lems, W; Oerlemans, R; Kathmann, I; Schalkwijk, C; Scheffer, G; Scheper, R; Jansen, G

    2004-01-01

    Objective: To determine whether overexpression of cell membrane associated drug efflux pumps belonging to the family of ATP binding cassette (ABC) proteins contributes to a diminished efficacy of sulfasalazine (SSZ) after prolonged cellular exposure to this disease modifying antirheumatic drug (DMARD). Methods: A model system of human T cells (CEM) was used to expose cells in vitro to increasing concentrations of SSZ for a period of six months. Cells were then characterised for the expression of drug efflux pumps: P-glycoprotein (Pgp, ABCB1), multidrug resistance protein 1 (MRP1, ABCC1), and breast cancer resistance protein (BCRP, ABCG2). Results: Prolonged exposure of CEM cells to SSZ provoked resistance to SSZ as manifested by a 6.4-fold diminished antiproliferative effect of SSZ compared with parental CEM cells. CEM cells resistant to SSZ (CEM/SSZ) showed a marked induction of ABCG2/BCRP, Pgp expression was not detectable, while MRP1 expression was even down regulated. A functional role of ABCG2 in SSZ resistance was demonstrated by 60% reversal of SSZ resistance by the ABCG2 blocker Ko143. Release of the proinflammatory cytokine tumour necrosis factor α (TNFα) was threefold higher in CEM/SSZ cells than in CEM cells. Moreover, twofold higher concentrations of SSZ were required to inhibit TNFα release from CEM/SSZ cells compared with CEM cells. Conclusion: Collectively, ABCG2 induction, augmented TNFα release, and less efficient inhibition of TNFα production by SSZ may contribute to diminished efficacy after prolonged exposure to SSZ. These results warrant further clinical studies to verify whether drug efflux pumps, originally identified for their roles in cytostatic drug resistance, can also be induced by SSZ or other DMARDs. PMID:14722201

  10. Multidrug Resistant Protein-Three Gene Regulation by the Transcription Factor Nrf2 in Human Bronchial Epithelial and Non-Small Cell Lung Carcinoma

    PubMed Central

    Mahaffey, Christopher M.; Zhang, Hongqiao; Rinna, Alessandra; Holland, William; Mack, Philip C.; Forman, Henry Jay

    2009-01-01

    Multidrug Resistant Proteins (MRP) are members of the ATP-binding cassette superfamily that facilitate detoxification by transporting toxic compounds, including chemotherapeutic drugs, out of cells. Chemotherapy, radiation, and other xenobiotic stresses have been shown to increase levels of select MRPs, although, the underlying mechanism remains largely unknown. Additionally, MRP3 is suspected of playing a role in the drug resistance of non-small cell lung carcinoma (NSCLC). Analysis of the MRP3 promoter revealed the presence of multiple putative electrophile responsive elements (EpRE), sequences that suggested possible regulation of this gene by Nrf2, the key transcription factor that binds to EpRE. The goal of this investigation was to determine whether MRP3 induction was dependent upon the transcription factor Nrf2. Keap1, a key regulator of Nrf2, sequesters Nrf2 in the cytoplasm, preventing entry into the nucleus. The electrophilic lipid peroxidation product, 4-hydroxy-2-nonenal (HNE) has been shown to modify Keap1 allowing Nrf2 to enter the nucleus. We found that HNE up-regulated MRP3 mRNA and protein levels in cell lines with wild type Keap1 (human bronchial epithelial cell line HBE1 and the NSCLC cell line H358), but not in the Keap1 mutant NSCLC cell lines (A549 and H460). Cell lines with mutant Keap1 had constitutively higher MRP3 that was not increased by HNE treatment. In HBE1 cells, silencing of Nrf2 with siRNA inhibited induction of MRP3 and by HNE. Finally, we found that silencing Nrf2 also increased the toxicity of cisplatin in H358 cells. The combined results therefore support the hypothesis that MRP3 induction by HNE involves Nrf2 activation. PMID:19345732

  11. β-casein nanovehicles for oral delivery of chemotherapeutic drug combinations overcoming P-glycoprotein-mediated multidrug resistance in human gastric cancer cells

    PubMed Central

    Bar-Zeev, Maya; Assaraf, Yehuda G.; Livney, Yoav D.

    2016-01-01

    Multidrug resistance (MDR) is a primary obstacle to curative cancer therapy. We have previously demonstrated that β-casein (β-CN) micelles (β-CM) can serve as nanovehicles for oral delivery and target-activated release of hydrophobic drugs in the stomach. Herein we introduce a novel nanosystem based on β-CM, to orally deliver a synergistic combination of a chemotherapeutic drug (Paclitaxel) and a P-glycoprotein-specific transport inhibitor (Tariquidar) individually encapsulated within β-CM, for overcoming MDR in gastric cancer. Light microscopy, dynamic light scattering and zeta potential analyses revealed solubilization of these drugs by β-CN, suppressing drug crystallization. Spectrophotometry demonstrated high loading capacity and good encapsulation efficiency, whereas spectrofluorometry revealed high affinity of these drugs to β-CN. In vitro cytotoxicity assays exhibited remarkable synergistic efficacy against human MDR gastric carcinoma cells with P-glycoprotein overexpression. Oral delivery of β-CN - based nanovehicles carrying synergistic drug combinations to the stomach constitutes a novel efficacious therapeutic system that may overcome MDR in gastric cancer. PMID:26989076

  12. MicroRNA-93-5p increases multidrug resistance in human colorectal carcinoma cells by downregulating cyclin dependent kinase inhibitor 1A gene expression

    PubMed Central

    Wang, Shi-Jun; Cao, Yun-Fei; Yang, Zu-Qing; Jiang, Zhi-Yuan; Cai, Bin; Guo, Jiao; Zhang, Sen; Zhang, Xiao-Long; Gao, Feng

    2017-01-01

    Multidrug resistance (MDR) impedes successful chemotherapy in colorectal carcinoma (CRC) and emerging evidence suggests that microRNAs (miRs) are involved in the development of MDR. In the present study, the role of miR-93-5p in the modulation of drug resistance in CRC was investigated using HCT-8 and MDR HCT-8/vincristine (VCR) cell lines. The results demonstrated upregulated expression of miR-93-5p and MDR protein 1 (MDR1) in HCT-8/VCR cells, compared with the parental HCT-8 cells. Furthermore, cyclin-dependent kinase inhibitor 1A (CDKN1A) was identified as a potential target of miR-93-5p using miR target analysis tools, including PicTar, TargetScan and miRanda. In addition, inhibition of miR-93-5p expression in HCT-8/VCR cells markedly downregulated MDR1 gene expression, upregulated CDKN1A gene expression and induced cell cycle arrest in G1. Conversely, the overexpression of miR-93-5p in HCT-8/VCR cells upregulated MDR1 gene expression, downregulated CDKN1A gene expression and promoted G1/S transition. Furthermore, the in vitro drug sensitivity assay performed suggested that downregulation of miR-93-5p enhanced the sensitivity of HCT-8/VCR cells to VCR, while the upregulation of miR-93-5p decreased the sensitivity of HCT-8 cells to VCR. In conclusion, the results of the present study suggest that miR-93-5p serves a role in the development of MDR through downregulating CDKN1A gene expression in CRC.

  13. Multidrug Resistance-Associated Protein 2 Expression Is Upregulated by Adenosine 5’-Triphosphate in Colorectal Cancer Cells and Enhances Their Survival to Chemotherapeutic Drugs

    PubMed Central

    Vinette, Valérie; Placet, Morgane; Arguin, Guillaume; Gendron, Fernand-Pierre

    2015-01-01

    Extracellular adenosine 5’-triphosphate (ATP) is a signaling molecule that induces a plethora of effects ranging from the regulation of cell proliferation to modulation of cancerous cell behavior. In colorectal cancer, ATP was reported to stimulate epithelial cell proliferation and possibly promote resistance to anti-cancer treatments. However, the exact role of this danger-signaling molecule on cancerous intestinal epithelial cells (IECs) in response to chemotherapeutic agents remains unknown. To address how ATP may influence the response of cancerous IECs to chemotherapeutic agents, we used Caco-2 cells, which display enterocyte-like features, to determine the effect of ATP on the expression of multidrug resistance-associated protein 2 (MRP2). Gene and protein expression were determined by quantitative real-time PCR (qRT-PCR) and Western blotting. Resistance to etoposide, cisplatin and doxorubicin was determined by MTT assays in response to ATP stimulation of Caco-2 cells and in cells for which MRP2 expression was down-regulated by shRNA. ATP increased the expression of MRP2 at both the mRNA and protein levels. MRP2 expression involved an ATP-dependent stimulation of the MEK/ERK signaling pathway that was associated with an increase in relative resistance of Caco-2 cells to etoposide. Abolition of MRP2 expression using shRNA significantly reduced the protective effect of MRP2 toward etoposide as well as to cisplatin and doxorubicin. This study describes the mechanism by which ATP may contribute to the chemoresistance of cancerous IECs in colorectal cancer. Given the heterogeneity of colorectal adenocarcinoma responses to anti-cancer drugs, these findings call for further study to understand the role of P2 receptors in cancer drug therapy and to develop novel therapies aimed at regulating P2 receptor activity. PMID:26295158

  14. Persistent reversal of P-glycoprotein-mediated daunorubicin resistance by tetrandrine in multidrug-resistant human T lymphoblastoid leukemia MOLT-4 cells.

    PubMed

    Liu, Zhen-Li; Hirano, Toshihiko; Tanaka, Sachiko; Onda, Kenji; Oka, Kitaro

    2003-11-01

    Multidrug resistance (MDR) represents a major problem in cancer chemotherapy. P-glycoprotein (P-gp), the drug efflux pump that mediates this resistance, can be inhibited by compounds with a variety of pharmacological functions, thus circumventing the MDR phenotype. The present study was performed to evaluate a unique MDR-reversal feature of a bisbenzylisoquinoline alkaloid tetrandrine (TET) in a P-gp expressing MOLT-4 MDR line (MOLT-4/DNR) established in our laboratory. Cell viability was determined by an MTT assay. P-gp function was characterized by determining the Rh123 accumulation/efflux capacity. P-gp overexpression in resistant MOLT-4/DNR cells was confirmed by flow cytometry analysis after staining with phycoerythrin-conjugated anti-P-gp monoclonal antibody 17F9. Compared to ciclosporin A (CsA), TET exhibited stronger activity to reverse drug resistance to daunorubicin (DNR), vinblastine (VLB) and doxorubicin (DOX) in MOLT-4/DNR cells. TET showed no cytotoxic effects on parental MOLT-4 cells lacking P-gp expression or on the resistant MOLT-4/DNR cells. TET modulated DNR cytotoxicity even after it was washed with the medium for 24 h, while CsA almost completely lost its reversal capability 24 h after washing. TET and CsA similarly increased the accumulation of Rh123 in resistant MOLT-4/DNR cells. However, TET inhibited Rh123 efflux from resistant cells even after washing with the medium, while CsA rapidly lost its ability to inhibit Rh123 efflux after washing. The current study suggests that TET enhances the cytotoxicity of anticancer drugs in the P-gp expressing MDR cell line by modulating P-gp in a different manner to the well-known P-gp inhibitor CsA.

  15. P-glycoprotein attenuates DNA repair activity in multidrug-resistant cells by acting through the Cbp-Csk-Src cascade.

    PubMed

    Lin, Li-Fang; Wu, Ming-Hsi; Pidugu, Vijaya Kumar; Ho, I-Ching; Su, Tsann-Long; Lee, Te-Chang

    2017-02-03

    Recent studies have demonstrated that P-glycoprotein (P-gp) expression impairs DNA interstrand cross-linking agent-induced DNA repair efficiency in multidrug-resistant (MDR) cells. To date, the detailed molecular mechanisms underlying how P-gp interferes with Src activation and subsequent DNA repair activity remain unclear. In this study, we determined that the C-terminal Src kinase-binding protein (Cbp) signaling pathway involved in the negative control of Src activation is enhanced in MDR cells. We also demonstrated that cells that ectopically express P-gp exhibit reduced activation of DNA damage response regulators, such as ATM, Chk2, Braca1 and Nbs1 and hence attenuated DNA double-strand break repair capacity and become more susceptible than vector control cells to DNA interstrand cross-linking (ICL) agents. Moreover, we demonstrated that P-gp can not only interact with Cbp and Src but also enhance the formation of inhibitory C-terminal Src kinase (Csk)-Cbp complexes that reduce phosphorylation of the Src activation residue Y416 and increase phosphorylation of the Src negative regulatory residue Y527. Notably, suppression of Cbp expression in MDR cells restores cisplatin-induced Src activation, improves DNA repair capacity, and increases resistance to ICL agents. Ectopic expression of Cbp attenuates cisplatin-induced Src activation and increases the susceptibility of cells to ICL agents. Together, the current results indicate that P-gp inhibits DNA repair activity by modulating Src activation via Cbp-Csk-Src cascade. These results suggest that DNA ICL agents are likely to have therapeutic potential against MDR cells with P-gp-overexpression.

  16. 3D-QSAR AND CONTOUR MAP ANALYSIS OF TARIQUIDAR ANALOGUES AS MULTIDRUG RESISTANCE PROTEIN-1 (MRP1) INHIBITORS

    PubMed Central

    Kakarla, Prathusha; Inupakutika, Madhuri; Devireddy, Amith R.; Gunda, Shravan Kumar; Willmon, Thomas Mark; Ranjana, KC; Shrestha, Ugina; Ranaweera, Indrika; Hernandez, Alberto J.; Barr, Sharla; Varela, Manuel F.

    2016-01-01

    One of the major obstacles to the successful chemotherapy towards several cancers is multidrug resistance of human cancer cells to anti-cancer drugs. An important contributor to multidrug resistance is the human multidrug resistance protein-1 transporter (MRP1), which is an efflux pump of the ABC (ATP binding cassette) superfamily. Thus, highly efficacious, third generation MRP1 inhibitors, like tariquidar analogues, are promising inhibitors of multidrug resistance and are under clinical trials. To maximize the efficacy of MRP1 inhibitors and to reduce systemic toxicity, it is important to limit the exposure of MRP1 inhibitors and anticancer drugs to normal tissues and to increase their co-localization with tumor cells. Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA) associated with 3D-Quantitiative structure-activity relationship (3D-QSAR) studies were performed on a series of tariquidar analogues, as selective MDR modulators. Best predictability was obtained with CoMFA model r2(non-cross-validated square of correlation coefficient) = 0.968, F value = 151.768 with five components, standard error of estimate = 0.107 while the CoMSIA yielded r2 = 0.982, F value = 60.628 with six components, and standard error of estimate = 0.154. These results indicate that steric, electrostatic, hydrophobic (lipophilic), and hydrogen bond donor substituents play significant roles in multidrug resistance modulation of tariquidar analogues upon MRP1. The tariquidar analogue and MRP1 binding and stability data generated from CoMFA and CoMSIA based 3D–contour maps may further aid in study and design of tariquidar analogues as novel, potent and selective MDR modulator drug candidates. PMID:26913287

  17. Drug Repurposing of the Anthelmintic Niclosamide to Treat Multidrug-Resistant Leukemia

    PubMed Central

    Hamdoun, Sami; Jung, Philipp; Efferth, Thomas

    2017-01-01

    Multidrug resistance, a major problem that leads to failure of anticancer chemotherapy, requires the development of new drugs. Repurposing of established drugs is a promising approach for overcoming this problem. An example of such drugs is niclosamide, a known anthelmintic that is now known to be cytotoxic and cytostatic against cancer cells. In this study, niclosamide showed varying activity against different cancer cell lines. It revealed better activity against hematological cancer cell lines CCRF-CEM, CEM/ADR5000, and RPMI-8226 compared to the solid tumor cell lines MDA-MB-231, A549, and HT-29. The multidrug resistant CEM/ADR5000 cells were similar sensitive as their sensitive counterpart CCRF-CEM (resistance ration: 1.24). Furthermore, niclosamide caused elevations in reactive oxygen species and glutathione (GSH) levels in leukemia cells. GSH synthetase (GS) was predicted as a target of niclosamide. Molecular docking showed that niclosamide probably binds to the ATP-binding site of GS with a binding energy of -9.40 kcal/mol. Using microscale thermophoresis, the binding affinity between niclosamide and recombinant human GS was measured (binding constant: 5.64 μM). COMPARE analyses of the NCI microarray database for 60 cell lines showed that several genes, including those involved in lipid metabolism, correlated with cellular responsiveness to niclosamide. Hierarchical cluster analysis showed five major branches with significant differences between sensitive and resistant cell lines (p = 8.66 × 105). Niclosamide significantly decreased nuclear factor of activated T-cells (NFAT) activity as predicted by promoter binding motif analysis. In conclusion, niclosamide was more active against hematological malignancies compared to solid tumors. The drug was particularly active against the multidrug-resistant CEM/ADR5000 leukemia cells. Inhibition of GSH synthesis and NFAT signaling were identified as relevant mechanisms for the anticancer activity of niclosamide

  18. Differential roles of ubiquitination in the degradation mechanism of cell surface-resident bile salt export pump and multidrug resistance-associated protein 2.

    PubMed

    Aida, Kensuke; Hayashi, Hisamitsu; Inamura, Kaori; Mizuno, Tadahaya; Sugiyama, Yuichi

    2014-03-01

    We previously showed that ubiquitination, a reversible post-translational modification, facilitates degradation of cell surface-resident bile salt export pump (BSEP) and multidrug resistance-associated protein 2 (MRP2), ABC transporters that are expressed at the canalicular membrane (CM) of hepatocytes. In the current study, its underlying mechanism was investigated by evaluating the role of ubiquitination in the processes of internalization and subsequent degradation of cell surface-resident BSEP and MRP2. Cell surface biotinylation analysis using Flp-In T-REx 293 cells showed that ectopic expression of Ub(Δ)(GG), which is ubiquitin (Ub) lacking the two C-terminal glycines essential for the Ub conjugation reaction, inhibited the internalization of 3× FLAG-BSEP, but not of MRP2, and the degradation of the internalized MRP2, but not of the internalized 3× FLAG-BSEP. Its inhibitory effect on BSEP internalization was also indicated by a time-lapse imaging analysis using the rat hepatoma cell line McA-RH7777 in which Ub(Δ)(GG) delayed the loss of fluorescence from photoactivated Dronpa-BSEP on the CM. The effect of Ub(Δ)(GG) on BSEP internalization in these experiments was abrogated by treatment with chlorpromazine, an inhibitor of clathrin-mediated endocytosis, and the introduction of a Y1311A mutation into BSEP. This mutation eliminates the ability of BSEP to interact with the AP2 adaptor complex, an adaptor protein required for cargo selection in clathrin-mediated endocytosis. In conclusion, our data suggest that ubiquitination facilitates clathrin-mediated endocytosis of BSEP and the degradation of internalized MRP2, leading to the degradation of the cell surface-resident form of both transporters.

  19. Multidrug-resistant phenotype in retinoblastoma correlates with P-glycoprotein expression.

    PubMed

    Chan, H S; Thorner, P S; Haddad, G; Gallie, B L

    1991-09-01

    Chemotherapy plays an important role in therapy for patients with extraocular and metastatic retinoblastoma. The authors used chemotherapy for management of selected patients with uncontrolled intraocular tumors or tumors larger and more posteriorly located than those conventionally treated with local cryotherapy or photocoagulation. Rapid regrowth of some tumors after an initial excellent chemotherapy response led us to investigate the hypothesis that failure of treatment is caused by P-glycoprotein-related multidrug resistance. By using a sensitive immunoperoxidase method, increased P-glycoprotein was detected in five multidrug-resistant and two selectively plant alkaloid-resistant retinoblastoma cell lines and in the intraocular and metastatic tumors from which they were derived. In four chemotherapy-treated cases, increased P-glycoprotein in the tumor samples correlated with clinically relevant drug resistance. None of the four chemosensitive tumor cell lines had increased P-glycoprotein expression. Continuous surveillance of P-glycoprotein levels in metastatic retinoblastoma may be a useful guide to drug therapy.

  20. 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.

  1. Multi-drug Resistance Protein 4 (MRP4)-mediated Regulation of Fibroblast Cell Migration Reflects a Dichotomous Role of Intracellular Cyclic Nucleotides*

    PubMed Central

    Sinha, Chandrima; Ren, Aixia; Arora, Kavisha; Moon, Chang-Suk; Yarlagadda, Sunitha; Zhang, Weiqiang; Cheepala, Satish B.; Schuetz, John D.; Naren, Anjaparavanda P.

    2013-01-01

    It has long been known that cyclic nucleotides and cyclic nucleotide-dependent signaling molecules control cell migration. However, the concept that it is not just the absence or presence of cyclic nucleotides, but a highly coordinated balance between these molecules that regulates cell migration, is new and revolutionary. In this study, we used multidrug resistance protein 4 (MRP4)-expressing cell lines and MRP4 knock-out mice as model systems and wound healing assays as the experimental system to explore this unique and emerging concept. MRP4, a member of a large family of ATP binding cassette transporter proteins, localizes to the plasma membrane and functions as a nucleotide efflux transporter and thus plays a role in the regulation of intracellular cyclic nucleotide levels. Here, we demonstrate that mouse embryonic fibroblasts (MEFs) isolated from Mrp4−/− mice have higher intracellular cyclic nucleotide levels and migrate faster compared with MEFs from Mrp4+/+ mice. Using FRET-based cAMP and cGMP sensors, we show that inhibition of MRP4 with MK571 increases both cAMP and cGMP levels, which results in increased migration. In contrast to these moderate increases in cAMP and cGMP levels seen in the absence of MRP4, a robust increase in cAMP levels was observed following treatment with forskolin and isobutylmethylxanthine, which decreases fibroblast migration. In response to externally added cell-permeant cyclic nucleotides (cpt-cAMP and cpt-cGMP), MEF migration appears to be biphasic. Altogether, our studies provide the first experimental evidence supporting the novel concept that balance between cyclic nucleotides is critical for cell migration. PMID:23264633

  2. Sensitization of multidrug resistant (MDR) cancer cells to vinblastine by novel acridones: correlation between anti-calmodulin activity and anti-MDR activity.

    PubMed

    Mayur, Y C; Padma, T; Parimala, B H; Chandramouli, K H; Jagadeesh, S; Gowda, N M Made; Thimmaiah, K N

    2006-01-01

    Multidrug resistance (MDR) of cancer cells remains to be an important cause of chemotherapy failure. Search for the new MDR reversal agents is still an unceasing challenge for the scientists. In an attempt to find clinically useful modulators of MDR, a series of 19 N(10)-substituted-2-bromoacridones has been synthesized. Parent compound 1, prepared by the Ullmann condensation of o-chlorobenzoic acid and p-bromoaniline, undergoes N-alkylation in the presence of a phase transfer catalyst. N-(omega-Chloroalkyl) analogues were subjected to iodide catalyzed nucleophilic substitution reaction with various secondary amines to get the products 3-10 and 12-19, which increased the uptake of vinblastine (VLB) in MDR KBCh(R)-8-5 cells to a greater extent (1.25 to 1.9-fold) than did a similar concentration of the standard modulator, verapamil (VRP). Results of the efflux experiment showed that each modulator significantly inhibited the efflux of VLB, suggesting that they may be competitors for P-gp. All the compounds effectively compete with [(3)H] azidopine for binding to P-gp, pointed out this transport membrane protein as their likely site of action. Compounds at IC(10) were evaluated for their efficacy to modulate the cytotoxicity of VLB in KBCh(R)-8-5 cells and found that the modulators enhanced the cytotoxicity of VLB by 3.8 to 34-fold. The study on the structure-activity relationship revealed that substitution of hydrogen atom at position C-2 in acridone nucleus by a bromine atom increased the cytotoxic and anti-MDR activities. The ability of acridones to inhibit calmodulin-dependent cyclic AMP phosphodiesterase has been determined and the results have shown a strong positive correlation between anti-calmodulin activity and cytotoxicity in KBCh(R)-8-5 cells or anti-MDR activity.

  3. Multidrug Resistance-Associated Protein 4 (MRP4/ABCC4) Controls Efflux Transport of Hesperetin Sulfates in Sulfotransferase 1A3-Overexpressing Human Embryonic Kidney 293 Cells.

    PubMed

    Sun, Hua; Wang, Xiao; Zhou, Xiaotong; Lu, Danyi; Ma, Zhiguo; Wu, Baojian

    2015-10-01

    Sulfonation is an important metabolic pathway for hesperetin. However, the mechanisms for the cellular disposition of hesperetin and its sulfate metabolites are not fully established. In this study, disposition of hesperetin via the sulfonation pathway was investigated using human embryonic kidney (HEK) 293 cells overexpressing sulfotransferase 1A3. Two monosulfates, hesperetin-3'-O-sulfate (H-3'-S) and hesperetin-7-O-sulfate (H-7-S), were rapidly generated and excreted into the extracellular compartment upon incubation of the cells with hesperetin. Regiospecific sulfonation of hesperetin by the cell lysate followed the substrate inhibition kinetics (Vmax = 0.66 nmol/min per mg, Km = 12.9 μM, and Ksi= 58.1 μM for H-3'-S; Vmax = 0.29 nmol/min per mg, Km = 14.8 μM, and Ksi= 49.1 μM for H-7-S). The pan-multidrug resistance-associated protein (MRP) inhibitor MK-571 at 20 μM essentially abolished cellular excretion of both H-3'-S and H-7-S (the excretion activities were only 6% of the control), whereas the breast cancer resistance protein-selective inhibitor Ko143 had no effects on sulfate excretion. In addition, knockdown of MRP4 led to a substantial reduction (>47.1%; P < 0.01) in sulfate excretion. Further, H-3'-S and H-7-S were good substrates for transport by MRP4 according to the vesicular transport assay. Moreover, sulfonation of hesperetin and excretion of its metabolites were well characterized by a two-compartment pharmacokinetic model that integrated drug uptake and sulfonation with MRP4-mediated sulfate excretion. In conclusion, the exporter MRP4 controlled efflux transport of hesperetin sulfates in HEK293 cells. Due to significant expression in various organs/tissues (including the liver and kidney), MRP4 should be a determining factor for the elimination and body distribution of hesperetin sulfates.

  4. Contribution of aquaporin 9 and multidrug resistance-associated protein 2 to differential sensitivity to arsenite between primary cultured chorion and amnion cells prepared from human fetal membranes

    SciTech Connect

    Yoshino, Yuta; Yuan, Bo; Kaise, Toshikazu; Takeichi, Makoto; Tanaka, Sachiko; Hirano, Toshihiko; Kroetz, Deanna L.; Toyoda, Hiroo

    2011-12-15

    Arsenic trioxide (arsenite, As{sup III}) has shown a remarkable clinical efficacy, whereas its side effects are still a serious concern. Therefore, it is critical to understand the effects of As{sup III} on human-derived normal cells for revealing the mechanisms underlying these side effects. We examined the effects of As{sup III} on primary cultured chorion (C) and amnion (A) cells prepared from human fetal membranes. A significant dose-dependent As{sup III}-mediated cytotoxicity was observed in the C-cells accompanied with an increase of lactate dehydrogenase (LDH) release. Higher concentrations of As{sup III} were required for the A-cells to show cytotoxicity and LDH release, suggesting that the C-cells were more sensitive to As{sup III} than the A-cells. The expression levels of aquaporin 9 (AQP9) were approximately 2 times higher in the C-cells than those in the A-cells. Both intracellular arsenic accumulation and its cytotoxicity in the C-cells were significantly abrogated by sorbitol, a competitive AQP9 inhibitor, in a dose-dependent manner. The protein expression levels of multidrug resistance-associated protein (MRP) 2 were downregulated by As{sup III} in the C-cells, but not in the A-cells. No significant differences in the expression levels of MRP1 were observed between C- and A-cells. The protein expression of P-glycoprotein (P-gp) was hardly detected in both cells, although a detectable amount of its mRNA was observed. Cyclosporine A, a broad-spectrum inhibitor for ABC transporters, and MK571, a MRP inhibitor, but not PGP-4008, a P-gp specific inhibitor, potently sensitized both cells to As{sup III}-mediated cytotoxicity. These results suggest that AQP9 and MRP2 are involved in controlling arsenic accumulation in these normal cells, which then contribute to differential sensitivity to As{sup III} cytotoxicity between these cells. -- Highlights: Black-Right-Pointing-Pointer Examination of effect of As{sup III} on primary cultured chorion (C) and amnion

  5. ABC transporters as multidrug resistance mechanisms and the development of chemosensitizers for their reversal

    PubMed Central

    Choi, Cheol-Hee

    2005-01-01

    One of the major problems related with anticancer chemotherapy is resistance against anticancer drugs. The ATP-binding cassette (ABC) transporters are a family of transporter proteins that are responsible for drug resistance and a low bioavailability of drugs by pumping a variety of drugs out cells at the expense of ATP hydrolysis. One strategy for reversal of the resistance of tumor cells expressing ABC transporters is combined use of anticancer drugs with chemosensitizers. In this review, the physiological functions and structures of ABC transporters, and the development of chemosensitizers are described focusing on well-known proteins including P-glycoprotein, multidrug resistance associated protein, and breast cancer resistance protein. PMID:16202168

  6. Intracellular pH and the Control of Multidrug Resistance

    NASA Astrophysics Data System (ADS)

    Simon, Sanford; Roy, Deborshi; Schindler, Melvin

    1994-02-01

    Many anticancer drugs are classified as either weak bases or molecules whose binding to cellular structures is pH dependent. Accumulation of these drugs within tumor cells should be affected by transmembrane pH gradients. Indeed, development of multidrug resistance (MDR) in tumor cells has been correlated with an alkaline shift of cytosolic pH. To examine the role of pH in drug partitioning, the distribution of two drugs, doxorubicin and daunomycin, was monitored in fibroblasts and myeloma cells. In both cell types the drugs rapidly accumulated within the cells. The highest concentrations were measured in the most acidic compartments-e.g., lysosomes. Modifying the cellular pH in drug-sensitive cells to mimic reported shifts in MDR caused an immediate change in the cellular drug concentration. Drug accumulation was enhanced by acidic shifts and reversed by alkaline shifts. All of these effects were rapid and reversible. These results demonstrate that the alkaline shift observed in MDR is sufficient to prevent the accumulation of chemotherapeutic drugs independent of active drug efflux.

  7. Intracellular pH and the control of multidrug resistance.

    PubMed Central

    Simon, S; Roy, D; Schindler, M

    1994-01-01

    Many anticancer drugs are classified as either weak bases or molecules whose binding to cellular structures is pH dependent. Accumulation of these drugs within tumor cells should be affected by transmembrane pH gradients. Indeed, development of multidrug resistance (MDR) in tumor cells has been correlated with an alkaline shift of cytosolic pH. To examine the role of pH in drug partitioning, the distribution of two drugs, doxorubicin and daunomycin, was monitored in fibroblasts and myeloma cells. In both cell types the drugs rapidly accumulated within the cells. The highest concentrations were measured in the most acidic compartments--e.g., lysosomes. Modifying the cellular pH in drug-sensitive cells to mimic reported shifts in MDR caused an immediate change in the cellular drug concentration. Drug accumulation was enhanced by acidic shifts and reversed by alkaline shifts. All of these effects were rapid and reversible. These results demonstrate that the alkaline shift observed in MDR is sufficient to prevent the accumulation of chemotherapeutic drugs independent of active drug efflux. Images PMID:8302842

  8. Oleanolic and maslinic acid sensitize soft tissue sarcoma cells to doxorubicin by inhibiting the multidrug resistance protein MRP-1, but not P-glycoprotein.

    PubMed

    Villar, Victor Hugo; Vögler, Oliver; Barceló, Francisca; Gómez-Florit, Manuel; Martínez-Serra, Jordi; Obrador-Hevia, Antònia; Martín-Broto, Javier; Ruiz-Gutiérrez, Valentina; Alemany, Regina

    2014-04-01

    The pentacyclic triterpenes oleanolic acid (OLA) and maslinic acid (MLA) are natural compounds present in many plants and dietary products consumed in the Mediterranean diet (e.g., pomace and virgin olive oils). Several nutraceutical activities have been attributed to OLA and MLA, whose antitumoral effects have been extensively evaluated in human adenocarcinomas, but little is known regarding their effectiveness in soft tissue sarcomas (STS). We assessed efficacy and molecular mechanisms involved in the antiproliferative effects of OLA and MLA as single agents or in combination with doxorubicin (DXR) in human synovial sarcoma SW982 and leiomyosarcoma SK-UT-1 cells. As single compound, MLA (10-100 μM) was more potent than OLA, inhibiting the growth of SW982 and SK-UT-1 cells by 70.3 ± 1.11% and 68.8 ± 1.52% at 80 μM, respectively. Importantly, OLA (80 μM) or MLA (30 μM) enhanced the antitumoral effect of DXR (0.5-10 μM) by up to 2.3-fold. On the molecular level, efflux activity of the multidrug resistance protein MRP-1, but not of the P-glycoprotein, was inhibited. Most probably as a consequence, DXR accumulated in these cells. Kinetic studies showed that OLA behaved as a competitive inhibitor of substrate-mediated MRP-1 transport, whereas MLA acted as a non-competitive one. Moreover, none of both triterpenes induced a compensatory increase in MRP-1 expression. In summary, OLA or MLA sensitized cellular models of STS to DXR and selectively inhibited MRP-1 activity, but not its expression, leading to a higher antitumoral effect possibly relevant for clinical treatment.

  9. Factors influencing the transfection efficiency and cellular uptake mechanisms of Pluronic P123-modified polypropyleneimine/pDNA polyplexes in multidrug resistant breast cancer cells.

    PubMed

    Gu, Jijin; Hao, Junguo; Fang, Xiaoling; Sha, Xianyi

    2016-04-01

    Generally, the major obstacles for efficient gene delivery are cellular internalization and endosomal escape of nucleic acid such as plasmid DNA (pDNA) or small interfering RNA (siRNA). We previously developed Pluronic P123 modified polypropyleneimine (PPI)/pDNA (P123-PPI/pDNA) polyplexes as a gene delivery system. The results showed that P123-PPI/pDNA polyplexes revealed higher transfection efficiency than PPI/pDNA polyplexes in multidrug resistant breast cancer cells. As a continued effort, the present investigation on the factors influencing the transfection efficiency, cellular uptake mechanisms, and intracellular fate of P123-PPI/pDNA polyplexes is reported. The presence of P123 was the main factor influencing the transfection efficiency of P123-PPI/pDNA polyplexes in MCF-7/ADR cells, but other parameters, such as N/P ratio, FBS concentration, incubation time and temperature were important as well. The endocytic inhibitors against clathrin-mediated endocytosis (CME), caveolae-mediated endocytosis (CvME), and macropinocytosis were involved in the internalization to investigate their effects on the cellular uptake and transfection efficiency of P123-PPI/pDNA polyplexes in vitro. The data showed that the internalization of P123-PPI/pDNA polyplexes was obtained from both CME and CvME. Colocalization experiments with TRITC-transferrin (CME indicator), Alexa Fluor 555-CTB (CvME indicator), monoclonal anti-α-tubulin (microtubule indicator), and LysoTracker Green (Endosome/lysosome indicator) were carried out to confirm the internalization routes. The results showed that both CME and CvME played vital roles in the effective transfection of P123-PPI/pDNA polyplexes. Endosome/lysosome system and skeleton, including actin filament and microtubule, were necessary for the transportation after internalization.

  10. Dual drug-loaded biofunctionalized amphiphilic chitosan nanoparticles: Enhanced synergy between cisplatin and demethoxycurcumin against multidrug-resistant stem-like lung cancer cells.

    PubMed

    Huang, Wei-Ting; Larsson, Mikael; Lee, Yi-Chi; Liu, Dean-Mo; Chiou, Guang-Yuh

    2016-12-01

    Lung cancer kills more humans than any other cancer and multidrug resistance (MDR) in cancer stem-like cells (CSC) is emerging as a reason for failed treatments. One concept that addresses this root cause of treatment failure is the utilization of nanoparticles to simultaneously deliver dual drugs to cancer cells with synergistic performance, easy to envision - hard to achieve. (1) It is challenging to simultaneously load drugs of highly different physicochemical properties into one nanoparticle, (2) release kinetics may differ between drugs and (3) general requirements for biomedical nanoparticles apply. Here self-assembled nanoparticles of amphiphilic carboxymethyl-hexanoyl chitosan (CHC) were shown to present nano-microenvironments enabling simultaneous loading of hydrophilic and hydrophobic drugs. This was expanded into a dual-drug nano-delivery system to treat lung CSC. CHC nanoparticles were loaded/chemically modified with the anticancer drug cisplatin and the MDR-suppressing Chinese herbal extract demethoxycurcumin, followed by biofunctionalization with CD133 antibody for enhanced uptake by lung CSC, all in a feasible one-pot preparation. The nanoparticles were characterized with regard to chemistry, size, zeta potential and drug loading/release. Biofunctionalized and non-functionalized nanoparticles were investigated for uptake by lung CSC. Subsequently the cytotoxicity of single and dual drugs, free in solution or in nanoparticles, was evaluated against lung CSC at different doses. From the dose response at different concentrations the degree of synergy was determined through Chou-Talalay's Plot. The biofunctionalized nanoparticles promoted synergistic effects between the drugs and were highly effective against MDR lung CSC. The efficacy and feasible one-pot preparation suggests preclinical studies using relevant disease models to be justified.

  11. Deficient activation of CD95 (APO-1/ Fas)-mediated apoptosis: a potential factor of multidrug resistance in human renal cell carcinoma

    PubMed Central

    Ramp, U; Dejosez, M; Mahotka, C; Czarnotta, B; Kalinski, T; Wenzel, M; Lorenz, I; Müller, M; Krammer, P; Gabbert, H E; Gerharz, C D

    2000-01-01

    factor for the multidrug resistance phenotype of human RCCs. © 2000 Cancer Research Campaign PMID:10839301

  12. Nonspecifically enhanced therapeutic effects of vincristine on multidrug-resistant cancers when coencapsulated with quinine in liposomes.

    PubMed

    Xu, Yuzhen; Qiu, Liyan

    2015-01-01

    The use of vincristine (VCR) to treat cancer has been limited by its dose-dependent toxicity and development of drug resistance after repeated administrations. In this study, we investigated the mechanism by which quinine hydrochloride (QN) acts as a sensitizer for VCR. Our experiments used three kinds of multidrug-resistant cancer cells and demonstrated that QN worked by inducing intracellular depletion of adenosine triphosphate, increasing adenosine triphosphatase activity, and decreasing P-glycoprotein expression. Based on these results, we designed and prepared a VCR and QN codelivery liposome (VQL) and investigated the effect of coencapsulated QN on the in vitro cytotoxicity of VCR in cells and three-dimensional multicellular tumor spheroids. The antitumor effects of the formulation were also evaluated in multidrug-resistant tumor-bearing mice. The results of this in vivo study indicated that VQL could reverse VCR resistance. In addition, it reduced tumor volume 5.4-fold when compared with other test groups. The data suggest that VQL could be a promising nanoscaled therapeutic agent to overcome multidrug resistance, and may have important clinical implications for the treatment of cancer.

  13. With no interaction, knockdown of Apollon and MDR1 reverse the multidrug resistance of human chronic myelogenous leukemia K562/ADM cells.

    PubMed

    Chen, Jie-Ru; Jia, Xiu-Hong; Wang, Hong; Yi, Ying-Jie; Li, You-Jie

    2017-03-29

    Chemotherapy is the main treatment method for patients with chronic myeloid leukemia (CML) and has achieved marked results. However, the acquisition of multidrug resistance (MDR) has seriously affected the quality of life and survival rate of patients. The overexpression of the inhibitors of apoptosis proteins (IAPs) and the adenosine triphosphate (ATP)-dependent binding cassette (ABC) transporters are the two main causes of MDR. Apollon and MDR1 are the most important and representative members, respectively, among the IAPs and ABC transporters. In the present study, we investigated the role of Apollon and MDR1 in chemotherapy resistance and their mechanism of interaction. We respectively knocked down the expression of Apollon and MDR1 using short hairpin RNA (shRNA) in adriamycin (ADM) resistant human CML K562 cells and examined the drug sensitivity, the consequences with regard to ADM accumulation and the alterations in the expression of Apollon and MDR1. The expression levels of Apollon and MDR1 mRNA were higher in the K562/ADM cells compared with the parental K562 cells as determined by reverse transcription‑polymerase chain reaction (RT-PCR). The plasmids of Apollon and MDR1 shRNA were respectively stably transfected into K562/ADM cells using Lipofectamine 2000. The transfection efficiency was detected by fluorescence microscopy. Cell Counting Kit-8 (CCK-8) assay revealed that Apollon or MDR1 knockdown significantly increased the chemosensitivity of the K562/ADM cells to ADM. Flow cytometric assay revealed that K562/ADM/shMDR1 cells exhibited a significantly increased intracellular accumulation of ADM, and that changes were not found in the K562/ADM/shApollon cells. Compared with the parental K562/ADM cells, a significantly decreased expression of Apollon mRNA and protein was determined in the K562/ADM/shApollon cells without affecting the expression of MDR1 as determined by RT-PCR and western blotting. Likewise, the expression levels of MDR1 m

  14. Sirolimus induces apoptosis and reverses multidrug resistance in human osteosarcoma cells in vitro via increasing microRNA-34b expression

    PubMed Central

    Zhou, Yan; Zhao, Rui-hua; Tseng, Kuo-Fu; Li, Kun-peng; Lu, Zhi-gang; Liu, Yuan; Han, Kun; Gan, Zhi-hua; Lin, Shu-chen; Hu, Hai-yan; Min, Da-liu

    2016-01-01

    Aim: Multi-drug resistance poses a critical bottleneck in chemotherapy. Given the up-regulation of mTOR pathway in many chemoresistant cancers, we examined whether sirolimus (rapamycin), a first generation mTOR inhibitor, might induce human osteosarcoma (OS) cell apoptosis and increase the sensitivity of OS cells to anticancer drugs in vitro. Methods: Human OS cell line MG63/ADM was treated with sirolimus alone or in combination with doxorubicin (ADM), gemcitabine (GEM) or methotrexate (MTX). Cell proliferation and apoptosis were detected using CCK-8 assay and flow cytometry, respectively. MiRNAs in the cells were analyzed with miRNA microarray. The targets of miR-34b were determined based on TargetScan analysis and luciferase reporter assays. The expression of relevant mRNA and proteins was measured using qRT-PCR and Western blotting. MiR-34, PAK1 and ABCB1 levels in 40 tissue samples of OS patients were analyzed using qRT-PCR and in situ hybridization assays. Results: Sirolimus (1–100 nmol/L) dose-dependently suppressed the cell proliferation (IC50=23.97 nmol/L) and induced apoptosis. Sirolimus (10 nmol/L) significantly sensitized the cells to anticancer drugs, leading to decreased IC50 values of ADM, GEM and MTX (from 25.48, 621.41 and 21.72 μmol/L to 4.93, 73.92 and 6.77 μmol/L, respectively). Treatment of with sirolimus increased miR-34b levels by a factor of 7.5 in the cells. Upregulation of miR-34b also induced apoptosis and increased the sensitivity of the cells to the anticancer drugs, whereas transfection with miR-34b-AMO, an inhibitor of miR-34b, reversed the anti-proliferation effect of sirolimus. Two key regulators of cell cycle, apoptosis and multiple drug resistance, PAK1 and ABCB1, were demonstrated to be the direct targets of miR-34b. In 40 tissue samples of OS patients, significantly higher miR-34 ISH score and lower PAK5 and ABCB1 scores were detected in the chemo-sensitive group. Conclusion: Sirolimus increases the sensitivity of human OS

  15. Chlorhexidine bathing for the prevention of colonization and infection with multidrug-resistant microorganisms in a hematopoietic stem cell transplantation unit over a 9-year period

    PubMed Central

    Mendes, Elisa Teixeira; Ranzani, Otavio T.; Marchi, Ana Paula; da Silva, Mariama Tomaz; Filho, José Ulysses Amigo; Alves, Tânia; Guimarães, Thais; Levin, Anna S.; Costa, Silvia Figueiredo

    2016-01-01

    Abstract Health care associated infections (HAIs) are currently among the major challenges to the care of hematopoietic stem cell transplantation (HSCT) patients. The objective of the present study was to evaluate the impact of 2% chlorhexidine (CHG) bathing on the incidence of colonization and infection with vancomycin-resistant Enterococcus (VRE), multidrug-resistant (MDR) gram-negative pathogens, and to evaluate their CHG minimum inhibitory concentration (MIC) after the intervention. A quasi-experimental study with duration of 9 years was conducted. VRE colonization and infection, HAI rates, and MDR gram-negative infection were evaluated by interrupted time series analysis. The antibacterial susceptibility profile and mechanism of resistance to CHG were analyzed in both periods by the agar dilution method in the presence or absence of the efflux pump inhibitor carbonyl cyanide-m-chlorophenyl hydrazone (CCCP) and presence of efflux pumps (qacA/E, qacA, qacE, cepA, AdeA, AdeB, and AdeC) by polymerase chain reaction (PCR). The VRE colonization and infection rates were significantly reduced in the postintervention period (P = 0.001). However, gram-negative MDR rates in the unit increased in the last years of the study. The CHG MICs for VRE increased during the period of exposure to the antiseptic. A higher MIC at baseline period was observed in MDR gram-negative strains. The emergence of a monoclonal Pseudomonas aeruginosa clone was observed in the second period. Concluding, CHG bathing was efficient regarding VRE colonization and infection, whereas no similar results were found with MDR gram-negative bacteria. PMID:27861350

  16. Identification of the hepatic efflux transporters of organic anions using double-transfected Madin-Darby canine kidney II cells expressing human organic anion-transporting polypeptide 1B1 (OATP1B1)/multidrug resistance-associated protein 2, OATP1B1/multidrug resistance 1, and OATP1B1/breast cancer resistance protein.

    PubMed

    Matsushima, Soichiro; Maeda, Kazuya; Kondo, Chihiro; Hirano, Masaru; Sasaki, Makoto; Suzuki, Hiroshi; Sugiyama, Yuichi

    2005-09-01

    Until recently, it was generally believed that the transport of various organic anions across the bile canalicular membrane was mainly mediated by multidrug resistance-associated protein 2 (MRP2/ABCC2). However, a number of new reports have shown that some organic anions are also substrates of multidrug resistance 1 (MDR1/ABCB1) and/or breast cancer resistance protein (BCRP/ABCG2), implying MDR1 and BCRP could also be involved in the biliary excretion of organic anions in humans. In the present study, we constructed new double-transfected Madin-Darby canine kidney II (MDCKII) cells expressing organic anion-transporting polypeptide 1B1 (OATP1B1)/MDR1 and OATP1B1/BCRP, and we investigated the transcellular transport of four kinds of organic anions, estradiol-17beta-d-glucuronide (EG), estrone-3-sulfate (ES), pravastatin (PRA), and cerivastatin (CER), to identify which efflux transporters mediate the biliary excretion of compounds using double-transfected cells. We observed the vectorial transport of EG and ES in all the double transfectants. MRP2 showed the highest efflux clearance of EG among these efflux transporters, whereas BCRP-mediated clearance of ES was the highest in these double transfectants. In addition, two kinds of 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, CER and PRA, were also substrates of all these efflux transporters. The rank order of the efflux clearance of PRA mediated by each transporter was the same as that of EG, whereas the contribution of MDR1 to the efflux of CER was relatively greater than for PRA. This experimental system is very useful for identifying which transporters are involved in the biliary excretion of organic anions that cannot easily penetrate the plasma membrane.

  17. Low dose of arsenic trioxide inhibits multidrug resistant-related P-glycoprotein expression in human neuroblastoma cell line.

    PubMed

    Liu, Ling; Li, Yang; Xiong, Xilin; Qi, Kai; Zhang, Chi; Fang, Jianpei; Guo, Haixia

    2016-12-01

    This study investigated arsenic trioxide (As2O3), cisplatin (DDP) and etoposide (Vp16) on the anticancer effects and P-glycoprotein (P-gp) expression in neuroblastoma (NB) SK-N-SH cells. The potential influence of As2O3, DDP and Vp16 currently included in NB routine treatment protocols on cytotoxicity in SK-N-SH cells was measured by flow cytometry and drug half-maximal inhibitory concentration (IC50) was established. Moreover, chemotherapeutic agent-mediated changes of cellular expression levels of resistant-related P-gp, was monitored using western blotting. The data showed that As2O3, DDP and Vp16 significantly inhibited the growth and survival of the SK-N-SH cells at different concentration. Notably, the levels of apoptosis were upregulated in SK-N-SH cells with an acceleration of the exposure time and the concentration of As2O3, DDP and Vp16. As2O3, DDP and Vp16 were observed with their IC50 values on SK-N-SH cells being 3 µM, 8 and 100 µg/ml, respectively. Flow cytometry analysis showed that As2O3 at low concentrations in SK-N-SH cells led to enhanced accumulation of cell populations in G2/M phase with increasing the exposure time, and increased levels of apoptosis. In contrast, we observed that SK-N-SH cell populations arrested in S phase by DDP and Vp16. In vitro examination revealed that following pretreatment of SK-N-SH cells with As2O3, the expression of P-gp was not increased. The expression of P-gp downregulation were noted following the group treated by As2O3 at 2 and 3 µM. Exposed to As2O3 at 3 µM for 72 h, SK-N-SH cells exhibited lower expression of P-gp than 2 µM As2O3 for 72 h. In contrast, the expression of P-gp was upregulated by DDP and VP16. In summary, SK-N-SH cells were responsive to chemotherapeutic agent-induced apoptosis in a dose-dependent and time-dependent manner. In particular, ours findings showed that low dose of As2O3 markedly reduced the P-gp expression and increased apoptotic cell death in human NB cell line.

  18. Cationic PEGylated liposomes incorporating an antimicrobial peptide tilapia hepcidin 2-3: an adjuvant of epirubicin to overcome multidrug resistance in cervical cancer cells.

    PubMed

    Juang, Vivian; Lee, Hsin-Pin; Lin, Anya Maan-Yuh; Lo, Yu-Li

    Antimicrobial peptides (AMPs) have been recently evaluated as a new generation of adjuvants in cancer chemotherapy. In this study, we designed PEGylated liposomes encapsulating epirubicin as an antineoplastic agent and tilapia hepcidin 2-3, an AMP, as a multidrug resistance (MDR) transporter suppressor and an apoptosis/autophagy modulator in human cervical cancer HeLa cells. Cotreatment of HeLa cells with PEGylated liposomal formulation of epirubicin and hepcidin 2-3 significantly increased the cytotoxicity of epirubicin. The liposomal formulations of epirubicin and/or hepcidin 2-3 were found to noticeably escalate the intracellular H2O2 and O2(-) levels of cancer cells. Furthermore, these treatments considerably reduced the mRNA expressions of MDR protein 1, MDR-associated protein (MRP) 1, and MRP2. The addition of hepcidin 2-3 in liposomes was shown to markedly enhance the intracellular epirubicin uptake and mainly localized into the nucleus. Moreover, this formulation was also found to trigger apoptosis and autophagy in HeLa cells, as validated by significant increases in the expressions of cleaved poly ADP ribose polymerase, caspase-3, caspase-9, and light chain 3 (LC3)-II, as well as a decrease in mitochondrial membrane potential. The apoptosis induction was also confirmed by the rise in sub-G1 phase of cell cycle assay and apoptosis percentage of annexin V/propidium iodide assay. We found that liposomal epirubicin and hepcidin 2-3 augmented the accumulation of GFP-LC3 puncta as amplified by chloroquine, implying the involvement of autophagy. Interestingly, the partial inhibition of necroptosis and the epithelial-mesenchymal transition by this combination was also verified. Altogether, our results provide evidence that coincubation with PEGylated liposomes of hepcidin 2-3 and epirubicin caused programmed cell death in cervical cancer cells through modulation of multiple signaling pathways, including MDR transporters, apoptosis, autophagy, and/or necroptosis

  19. Cationic PEGylated liposomes incorporating an antimicrobial peptide tilapia hepcidin 2–3: an adjuvant of epirubicin to overcome multidrug resistance in cervical cancer cells

    PubMed Central

    Juang, Vivian; Lee, Hsin-Pin; Lin, Anya Maan-Yuh; Lo, Yu-Li

    2016-01-01

    Antimicrobial peptides (AMPs) have been recently evaluated as a new generation of adjuvants in cancer chemotherapy. In this study, we designed PEGylated liposomes encapsulating epirubicin as an antineoplastic agent and tilapia hepcidin 2–3, an AMP, as a multidrug resistance (MDR) transporter suppressor and an apoptosis/autophagy modulator in human cervical cancer HeLa cells. Cotreatment of HeLa cells with PEGylated liposomal formulation of epirubicin and hepcidin 2–3 significantly increased the cytotoxicity of epirubicin. The liposomal formulations of epirubicin and/or hepcidin 2–3 were found to noticeably escalate the intracellular H2O2 and O2− levels of cancer cells. Furthermore, these treatments considerably reduced the mRNA expressions of MDR protein 1, MDR-associated protein (MRP) 1, and MRP2. The addition of hepcidin 2–3 in liposomes was shown to markedly enhance the intracellular epirubicin uptake and mainly localized into the nucleus. Moreover, this formulation was also found to trigger apoptosis and autophagy in HeLa cells, as validated by significant increases in the expressions of cleaved poly ADP ribose polymerase, caspase-3, caspase-9, and light chain 3 (LC3)-II, as well as a decrease in mitochondrial membrane potential. The apoptosis induction was also confirmed by the rise in sub-G1 phase of cell cycle assay and apoptosis percentage of annexin V/propidium iodide assay. We found that liposomal epirubicin and hepcidin 2–3 augmented the accumulation of GFP-LC3 puncta as amplified by chloroquine, implying the involvement of autophagy. Interestingly, the partial inhibition of necroptosis and the epithelial–mesenchymal transition by this combination was also verified. Altogether, our results provide evidence that coincubation with PEGylated liposomes of hepcidin 2–3 and epirubicin caused programmed cell death in cervical cancer cells through modulation of multiple signaling pathways, including MDR transporters, apoptosis, autophagy, and

  20. The enriched fraction of Elephantopus scaber Triggers apoptosis and inhibits multi-drug resistance transporters in human epithelial cancer cells

    PubMed Central

    Beeran, Asmy Appadath; Maliyakkal, Naseer; Rao, Chamallamudi Mallikarjuna; Udupa, Nayanabhirama

    2015-01-01

    Background: Medicinal plants have played an important role in the development of clinically useful anticancer agents. Elephantopus scaber (Asteraceae) (ES) is widely used in Indian traditional system of medicine for the treatment of various ailments including cancer. Objective: To investigate anticancer effects of ES in human epithelial cancer cells. Materials and Methods: Cytotoxicity of ethanolic extract of ES (ES-ET) and its fractions, such as ES Petroleum ether fraction (ES-PET), ES Dichloromethane fraction (ES DCM), n Butyl alcohol fraction (ES-BT), and ES-Rest (ES-R) were assessed in human epithelial cancer cell lines using sulforhodamine B (SRB) assay. Acridine orange/ethidium bromide assay and Hoechst 33342 assays were used to gauge induction of apoptosis. Cell cycle analysis and micronuclei assay were used to assess cell cycle specific pharmacological effects and drug induced genotoxicty. Further, the ability of ES to inhibit multi drug resistant (MDR) transporters (ABC-B1 and ABC-G2) was determined by Rhodamine (Rho) and Mitoxantrone (MXR) efflux assays. Results: The enriched fraction of ES (ES DCM) possessed dose-dependent potent cytotoxicity in human epithelial cancer cells. Further, treatment of cancer cells (HeLa, A549, MCF-7, and Caco-2) with ES DCM showed hall mark properties of apoptosis (membrane blebbing, nuclear condensation etc.). Similarly, ES DCM caused enhanced sub G0 content and micronuclei formation indicating the induction of apoptosis and drug induced genotoxicity in cancer cells, respectively. Interestingly, ES DCM inhibited MDR transporters (ABC B1 and ABC G2) in cancer cells. Conclusion: The enriched fraction of ES imparted cytotoxic effects, triggered apoptosis, induced genotoxicity, and inhibited MDR transporters in human epithelial cancer cells. Thus, ES appears to be potential anticancer agent. PMID:25829763

  1. STROBE-compliant integrin through focal adhesion involve in cancer stem cell and multidrug resistance of ovarian cancer

    PubMed Central

    Wei, Luwei; Yin, Fuqiang; Zhang, Wei; Li, Li

    2017-01-01

    Abstract Cancer stem cells (CSCs) are considered to be the root of carcinoma relapse and drug resistance in ovarian cancer. Hunting for the potential CSC genes and explain their functions would be a feasible strategy to meet the challenge of the drug resistance in ovarian cancer. In this study, we performed bioinformatic approaches such as biochip data extraction and pathway enrichment analyses to elucidate the mechanism of the CSC genes in regulation of drug resistance. Potential key genes, integrins, were identified to be related to CSC in addition to their associations with drug resistance and prognosis in ovarian cancer. A total of 36 ovarian CSC genes involved in regulation of drug resistance were summarized, and potential drug resistance-related CSC genes were identified based on 3 independent microarrays retrieved from the Gene Expression Omnibus (GEO) Profiles. Pathway enrichment of CSC genes associated with drug resistance in ovarian cancer indicated that focal adhesion signaling might play important roles in CSC genes-mediated drug resistance. Integrins are members of the adhesion molecules family, and integrin subunit alpha 1, integrin subunit alpha 5, and integrin subunit alpha 6 (ITGA6) were identified as central CSC genes and their expression in side population cells, cisplatin-resistant SKOV3 (SKOV3/DDP2) cells, and cisplatin-resistant A2780 (A2780/DDP) cells were dysregulated as measured by real-time quantitative polymerase chain reaction. The high expression of ITGA6 in 287 ovarian cancer patients of TCGA cohort was significantly associated with poorer progression-free survival. This study provide the basis for further understanding of CSC genes in regulation of drug resistance in ovarian cancer, and integrins could be a potential biomarker for prognosis of ovarian cancer. PMID:28328815

  2. Vitamin E Reverses Multidrug Resistance In Vitro and In Vivo

    PubMed Central

    Tang, Jingling; Fu, Qiang; Wang, Yongjun; Racette, Kelly; Wang, Dun; Liu, Feng

    2013-01-01

    Multidrug resistance (MDR) is a major obstacle to successful and effective chemotherapeutic treatments of cancers. This study explored the reversal effects of vitamin E on MDR tumor cells in vitro and in vivo, elucidating the potential mechanism of this reversal. VE at a concentration of 50 μM exhibited a significant reversal of the MDR effect (compared to only PTX in DMSO, p < 0.05) in two human MDR cell lines (H460/taxR and KB-8-5). The MDR cell xenograft model was established to investigate the effect of VE on reversing MDR in vivo. Mice intravenously injected with Taxol (10 mg/kg) with VE (500 mg/kg, IP) showed an ability to overcome the MDR. VE and its derivatives can significantly increase intracellular accumulation of rhodamine 123 and doxorubicin (P-gp substrate), but not alter the levels of P-gp expression. These treatments also did not decrease the levels of intracellular ATP, but were still able to inhibit the verapamil-induced ATPase activity of P-gp. The new application of VE as an MDR sensitizer will be attractive due to the safety of this treatment. PMID:23624302

  3. Multidrug resistance: an emerging crisis.

    PubMed

    Tanwar, Jyoti; Das, Shrayanee; Fatima, Zeeshan; Hameed, Saif

    2014-01-01

    The resistance among various microbial species (infectious agents) to different antimicrobial drugs has emerged as a cause of public health threat all over the world at a terrifying rate. Due to the pacing advent of new resistance mechanisms and decrease in efficiency of treating common infectious diseases, it results in failure of microbial response to standard treatment, leading to prolonged illness, higher expenditures for health care, and an immense risk of death. Almost all the capable infecting agents (e.g., bacteria, fungi, virus, and parasite) have employed high levels of multidrug resistance (MDR) with enhanced morbidity and mortality; thus, they are referred to as "super bugs." Although the development of MDR is a natural phenomenon, the inappropriate use of antimicrobial drugs, inadequate sanitary conditions, inappropriate food-handling, and poor infection prevention and control practices contribute to emergence of and encourage the further spread of MDR. Considering the significance of MDR, this paper, emphasizes the problems associated with MDR and the need to understand its significance and mechanisms to combat microbial infections.

  4. Overcoming cancer multidrug resistance by codelivery of doxorubicin and verapamil with hydrogel nanoparticles.

    PubMed

    Qin, Ming; Lee, Yong-Eun Koo; Ray, Aniruddha; Kopelman, Raoul

    2014-08-01

    The efficacy of chemotherapy is often inhibited by multidrug resistance (MDR). A highly engineerable hydrogel nanoparticle (NP) serves as a carrier for the optimal codelivery to tumor cells of the chemodrug, doxorubicin (Dox) and the chemosensitizer, verapamil (Vera), aiming at alleviating tumor MDR. The hydrogel NPs are prepared via the copolymerization of acrylamide and 2-carboxyethyl acrylate. Dox and Vera are post-loaded into the respective NPs, with drug loading around 7.7 wt% and 8.0 wt%, respectively. The codelivery of Dox-NPs and Vera-NPs increases the intracellular accumulation of Dox, and significantly enhances the cell killing ability of Dox with respect to NCI/ADR-RES cells in vitro. These findings suggest that such codelivery nanoplatforms provide a promising route for overcoming tumor MDR.

  5. Simulated microgravity reduces mRNA levels of multidrug resistance genes 4 and 5 in non-metastatic human melanoma cells

    NASA Astrophysics Data System (ADS)

    Eiermann, Peter; Tsiockas, Wasiliki; Hauslage, Jens; Hemmersbach, Ruth; Gerzer, Rupert; Ivanova, Krassimira

    Multidrug resistance proteins (MRP) are members of the ATP-binding cassette transporter superfamily that are able to export a large variety of substances into the extracellular space in-cluding nucleoside and nucleotide base analogs used in antiviral and anticancer therapy. MRP4 and 5 (MRP4/5) particularly transport cyclic nucleotides, e.g. guanosine 3',5'-cyclic monophos-phate (cGMP). The second messenger cGMP, which is synthesized by the catalytic activity of the guanylyl cyclase (GC), plays an import role in vasodilatation, smooth muscle relaxation, and nitric oxide (NO)-induced perturbation of melanocyte-extracellular matrix interactions. In previous studies we have reported that different GC isoforms are responsible for cGMP synthe-sis in melanocytic cells. Normal human melanocytes and non-metastatic melanoma cell lines predominantly express the NO-sensitive soluble GC isoform (sGC), a heterodimeric protein consisting of α and β subunits. Metastatic melanoma cells lack the expression of the β sub-unit and show up-regulated activities of the particulate isoforms. We have further found that long-term exposure to hypergravity (5 g for 24 h) induced an increased cGMP export in normal human melanocytes, and non-metastatic, but not in metastatic human melanoma cells as a re-sult of up-regulated MRP4/5 expression. The aim of the present study is to investigate whether simulated microgravity may also alter the expression of MRP4/5 in non-metastatic melanoma cells. Experiments were performed using a fast-rotating clinostat (60 rpm) with one rotation axis. The non-metastatic 1F6 melanoma cells were exposed to simulated microgravity (up to 1.21x10-2 g) for 24 h. The mRNA analyses were performed by a relative calibrator-normalized and efficiency corrected quantitative polymerase chain reaction (Light Cycler R , Roche). Our data show a reduced expression of approximately 35% for MRP4 and of 50% for MRP5 in simulated microgravity in comparison to 1 g controls. Also, the

  6. A nanoparticulate pre-chemosensitizer for efficacious chemotherapy of multidrug resistant breast cancer

    PubMed Central

    Guo, Shengrong; Lv, Li; Shen, Yuanyuan; Hu, Zhongliang; He, Qianjun; Chen, Xiaoyuan

    2016-01-01

    Small-molecule chemosensitizers can reverse cancer multidrug resistance (MDR), thus significantly improving the in vitro effect of chemotherapy drugs for MDR cancer cells, however, their in vivo effects are not always very good, because they are difficult to effectively accumulate in tumor and enter the same cancer with chemotherapy drugs after systemic administration due to individual biopharmaceutical properties. To overcome these limitations, here we study a novel nanoparticular pre-chemosensitizer which can be also used as nanocarrier of chemotherapy drugs. We take an ‘all in one’ approach to develop a self-assembled nanoparticle formula of amphiphilic poly(curcumin-dithiodipropionic acid)-b-poly(ethylene glycol)-biotin. The nanoparticle is capable of tumor-targeted delivery, responsive degradation at the intracellular level of glutathione and subsequent intracellular co-release of the chemosensitizer curcumin and the encapsulated chemotherapeutic drug doxorubicin to maximize a synergistic effect of chemosensitization and chemotherapy. We demonstrate that the antitumor efficacy of nanoparticle is much superior to that of doxorubicin in the multidrug resistant MCF-7/ADR xenografted nude mice. PMID:26875787

  7. Mechanisms of multidrug resistance in cancer.

    PubMed

    Gillet, Jean-Pierre; Gottesman, Michael M

    2010-01-01

    The development of multidrug resistance (MDR) to chemotherapy remains a major challenge in the treatment of cancer. Resistance exists against every effective anticancer drug and can develop by numerous mechanisms including decreased drug uptake, increased drug efflux, activation of detoxifying systems, activation of DNA repair mechanisms, evasion of drug-induced apoptosis, etc. In the first part of this chapter, we briefly summarize the current knowledge on individual cellular mechanisms responsible for MDR, with a special emphasis on ATP-binding cassette transporters, perhaps the main theme of this textbook. Although extensive work has been done to characterize MDR mechanisms in vitro, the translation of this knowledge to the clinic has not been crowned with success. Therefore, identifying genes and mechanisms critical to the development of MDR in vivo and establishing a reliable method for analyzing clinical samples could help to predict the development of resistance and lead to treatments designed to circumvent it. Our thoughts about translational research needed to achieve significant progress in the understanding of this complex phenomenon are therefore discussed in a third section. The pleotropic response of cancer cells to chemotherapy is summarized in a concluding diagram.

  8. Diversity among multidrug-resistant enterococci.

    PubMed Central

    Murray, B. E.

    1998-01-01

    Enterococci are associated with both community- and hospital-acquired infections. Even though they do not cause severe systemic inflammatory responses, such as septic shock, enterococci present a therapeutic challenge because of their resistance to a vast array of antimicrobial drugs, including cell-wall active agents, all commercially available aminoglycosides, penicillin and ampicillin, and vancomycin. The combination of the latter two occurs disproportionately in strains resistant to many other antimicrobial drugs. The propensity of enterococci to acquire resistance may relate to their ability to participate in various forms of conjugation, which can result in the spread of genes as part of conjugative transposons, pheromone-responsive plasmids, or broad host-range plasmids. Enterococcal hardiness likely adds to resistance by facilitating survival in the environment (and thus enhancing potential spread from person to person) of a multidrug-resistant clone. The combination of these attributes within the genus Enterococcus suggests that these bacteria and their resistance to antimicrobial drugs will continue to pose a challenge. PMID:9452397

  9. Synergistic Cisplatin/Doxorubicin Combination Chemotherapy for Multidrug-Resistant Cancer via Polymeric Nanogels Targeting Delivery.

    PubMed

    Wu, Haiqiu; Jin, Haojie; Wang, Cun; Zhang, Zihao; Ruan, Haoyu; Sun, Luyan; Yang, Chen; Li, Yongjing; Qin, Wenxin; Wang, Changchun

    2017-03-08

    Combination chemotherapy has been proposed to achieve synergistic effect and minimize drug dose for cancer treatment in clinic application. In this article, the stimuli-responsive polymeric nanogels (<100 nm in size) based on poly(acrylic acid) were designed as codelivery system for doxorubicin and cisplatin to overcome drug resistance. By chelation, electrostatic interaction, and π-π stacking interactions, the nanogels could encapsulate doxorubicin and cisplatin with designed ratio and high capacity. Compared with free drugs, the nanogels could deliver more drugs into MCF-7/ADR cells. Significant accumulation in tumor tissues was observed in the biodistribution experiments. The in vitro antitumor studies demonstrated the superior cell-killing activity of the nanogel drug delivery system with a combination index of 0.84, which indicated the great synergistic effect. All the antitumor experimental data revealed that the combination therapy was effective for the multidrug-resistant MCF-7/ADR tumor with reduced side effects.

  10. Reversers of the multidrug resistance transporter P-glycoprotein.

    PubMed

    Stein, Wilfred D

    2002-05-01

    Multidrug resistance can arise from the presence of the membrane-bound pump, P-glycoprotein, in a tumor. Major efforts have been made to develop inhibitors of this pump, and a number of promising blockers have reached late stages of clinical trials. The kinetics of the inhibition of P-glycoprotein is complex, with binding sites that can interact synergistically. Reversers of increased affinity and specificity could, in principle, be developed on the basis of these synergies, and offer some promise in cancer therapeutics.

  11. 4,5-Di-substituted benzyl-imidazol-2-substituted amines as the structure template for the design and synthesis of reversal agents against P-gp-mediated multidrug resistance breast cancer cells.

    PubMed

    Zhang, Nan; Zhang, Zhaohui; Wong, Iris L K; Wan, Shengbiao; Chow, Larry M C; Jiang, Tao

    2014-08-18

    Over-expression of P-glycoprotein (P-gp), a primary multidrug transporter which is located in plasma membranes, plays a major role in the multidrug resistance (MDR) of cytotoxic chemotherapy. Naamidines are a class of marine imidazole alkaloids isolated from Leucetta and Clathrina sponges, possessing a Y-shaped scaffold. Based on the results previously obtained from the third-generation MDR modulator ONT-093 and other modulators developed in our group, we designed and synthesized a series of novel 4,5-di-substituted benzyl-1-methyl-1H-imidazol-2-substituted amines using the Naamidine scaffold as the structure template. Subsequently, their reversing activity for Taxol resistance has been evaluated in P-gp-mediated multidrug resistance breast cancer cell line MDA435/LCC6MDR. Compounds 12c with a Y-shaped scaffold, and compound 17c which is 'X-shaped' scaffold and possesses a 4-diethylamino group at aryl ring B, turned out to be the most potent P-gp modulators. It appears that compounds 12c and 17c at 1 μM concentration can sensitize LCC6MDR cells toward Taxol by 26.4 and 24.5 folds, with an EC50 212.5 and 210.5 nM, respectively. These two compounds are about 5-6 folds more potent than verapamil (RF = 4.5). Moreover, compounds 12c and 17c did not exhibit obvious cytotoxicity in either cancer cell lines or normal mouse fibroblast cell lines. This study has demonstrated that the synthetic Naamidine analogues can be potentially employed as effective, safe modulators for the P-gp-mediated drug resistance cancer cells.

  12. The multidrug-resistance transporter ABCB5 is expressed in human placenta.

    PubMed

    Volpicelli, Elgida R; Lezcano, Cecilia; Zhan, Qian; Girouard, Sasha D; Kindelberger, David W; Frank, Markus H; Frank, Natasha Y; Crum, Christopher P; Murphy, George F

    2014-01-01

    ATP-binding cassette (ABC) transporters in placenta protectively transport drugs and xenobiotics. ABCB5 [subfamily B (MDR/TAP)] is a novel ABC multidrug-resistance transporter that also mediates cell fusion, stem cell function, and vasculogenic plasticity. Immunohistochemistry and double-labeling immunofluorescence staining for ABCB5 and ABCB5/CD200, respectively, was performed on formalin-fixed, paraffin-embedded placental tissue from 5 first trimester, 5 second trimester, and 5 term pregnancies as well as 5 partial moles, and 5 complete moles. In addition, tumor cells from 5 choriocarcinoma and 5 placental site trophoblastic tumor cases were examined. ABCB5 staining was observed in villous trophoblasts in 100% (5/5) of first trimester placentas (with progressive decrease in term placentas); 100% of partial moles (5/5); and 100% of complete moles (5/5). Notably, reactivity was discretely restricted to the inner trophoblast layer, with no staining of overlying syncytiotrophoblast. Antibody specificity and localization was confirmed further by in situ hybridization. ABCB5 expression was retained in 20% of choriocarcinomas (1/5) and 40% of placental site trophoblastic tumors (2/5). Prior studies have localized expression of multidrug-resistance-1, also known as ABCB1, within the syncytiotrophoblast of early placentas, where it serves a protective function as an efflux transporter. Our results show that ABCB5 is preferentially expressed in the cytotrophoblast layer of placental villi. The expression of this novel biomarker at the maternal-fetal interface raises questions on its role in placental structure and function as well as on its potential contribution to the protective efflux provided by other P-glycoprotein transporters.

  13. Elucidation of the therapeutic enhancer mechanism of poly-S-nitrosated human serum albumin against multidrug-resistant tumor in animal models.

    PubMed

    Ishima, Yu; Hara, Marie; Kragh-Hansen, Ulrich; Inoue, Aki; Suenaga, Ayaka; Kai, Toshiya; Watanabe, Hiroshi; Otagiri, Masaki; Maruyama, Toru

    2012-11-28

    Human serum albumin (HSA) is the most abundant circulating protein and its S-nitrosated form serves as a reservoir of nitric oxide (NO). Previously, we prepared poly-S-nitrosated HSA (Poly-SNO-HSA) by incubation with Traut's Reagent and isopentyl nitrite and evaluated its potential as a novel anticancer agent through apoptosis involving the caspase-3 pathway. Recently, NO donors such as nitroglycerin were reported to revert the resistance to anticancer agents. Therefore, now we have evaluated the effect of the above type of Poly-SNO-HSA on the resistance to doxorubicin (dx) in human myelogenous leukemic cells (K562 cells). P-gp expression and dx accumulation in K562 and dx-resistant K562 cells (K562/dx cells) were quantified using Western blot and FACS analysis, respectively. Compared with parent K562 cells, higher expression of P-gp and lower accumulation of dx were shown in K562/dx cells. Poly-SNO-HSA caused increased dx accumulation in K562/dx cells by decreasing the expressions of P-gp and HIF-1α. Other experiments with the guanylate cyclase inhibitor ODQ and 8-Br-cGMP revealed that also a cGMP signaling pathway is involved in the Poly-SNO-HSA induced increase in dx accumulation. Furthermore, in vivo studies showed that co-treatment with Poly-SNO-HSA enhanced the anticancer effect of dx in K562/dx cells-bearing mice. Thus, in addition to its proapoptotic effect Poly-SNO-HSA can in an efficient manner revert drug resistance both in vitro and in vivo, and two pathways for this effect have been identified.

  14. Mesoporous silica nanoparticles loading doxorubicin reverse multidrug resistance: performance and mechanism

    NASA Astrophysics Data System (ADS)

    Shen, Jianan; He, Qianjun; Gao, Yu; Shi, Jianlin; Li, Yaping

    2011-10-01

    Multidrug resistance (MDR) is one of the major obstacles for successful chemotherapy in cancer. One of the effective approaches to overcome MDR is to use nanoparticle-mediated drug delivery to increase drug accumulation in drug resistant cancer cells. In this work, we first report that the performance and mechanism of an inorganic engineered delivery system based on mesoporous silica nanoparticles (MSNs) loading doxorubicin (DMNs) to overcome the MDR of MCF-7/ADR (a DOX-resistant and P-glycoprotein (P-gp) over-expression cancer cell line). The experimental results showed that DMNs could enhance the cellular uptake of doxorubicin (DOX) and increase the cell proliferation suppression effect of DOX against MCF-7/ADR cells. The IC50 of DMNs against MCF-7/ADR cells was 8-fold lower than that of free DOX. However, an improved effect of DOX in DMNs against MCF-7 cells (a DOX-sensitive cancer cell line) was not found. The increased cellular uptake and nuclear accumulation of DOX delivered by DMNs in MCF-7/ADR cells was confirmed by confocal laser scanning microscopy, and could result from the down-regulation of P-gp and bypassing the efflux action by MSNs themselves. The cellular uptake mechanism of DMNs indicated that the macropinocytosis was one of the pathways for the uptake of DMNs by MCF-7/ADR cells. The in vivo biodistribution showed that DMNs induced a higher accumulation of DOX in drug resistant tumors than free DOX. These results suggested that MSNs could be an effective delivery system to overcome multidrug resistance.

  15. Applications of nanoparticle drug delivery systems for the reversal of multidrug resistance in cancer

    PubMed Central

    HUANG, YINGHONG; COLE, SUSAN P.C.; CAI, TIANGE; CAI, YU

    2016-01-01

    Multidrug resistance (MDR) to chemotherapy presents a major obstacle in the treatment of cancer patients, which directly affects the clinical success rate of cancer therapy. Current research aims to improve the efficiency of chemotherapy, whilst reducing toxicity to prolong the lives of cancer patients. As with good biocompatibility, high stability and drug release targeting properties, nanodrug delivery systems alter the mechanism by which drugs function to reverse MDR, via passive or active targeting, increasing drug accumulation in the tumor tissue or reducing drug elimination. Given the potential role of nanodrug delivery systems used in multidrug resistance, the present study summarizes the current knowledge on the properties of liposomes, lipid nanoparticles, polymeric micelles and mesoporous silica nanoparticles, together with their underlying mechanisms. The current review aims to provide a reliable basis and useful information for the development of new treatment strategies of multidrug resistance reversal using nanodrug delivery systems. PMID:27347092

  16. Imidazoacridinone-dependent lysosomal photodestruction: a pharmacological Trojan horse approach to eradicate multidrug-resistant cancers

    PubMed Central

    Adar, Y; Stark, M; Bram, E E; Nowak-Sliwinska, P; van den Bergh, H; Szewczyk, G; Sarna, T; Skladanowski, A; Griffioen, A W; Assaraf, Y G

    2012-01-01

    Multidrug resistance (MDR) remains a primary hindrance to curative cancer therapy. Thus, introduction of novel strategies to overcome MDR is of paramount therapeutic significance. Sequestration of chemotherapeutics in lysosomes is an established mechanism of drug resistance. Here, we show that MDR cells display a marked increase in lysosome number. We further demonstrate that imidazoacridinones (IAs), which are cytotoxic fluorochromes, undergo a dramatic compartmentalization in lysosomes because of their hydrophobic weak base nature. We hence developed a novel photoactivation-based pharmacological Trojan horse approach to target and eradicate MDR cancer cells based on photo-rupture of IA-loaded lysosomes and tumor cell lysis via formation of reactive oxygen species. Illumination of IA-loaded cells resulted in lysosomal photodestruction and restoration of parental cell drug sensitivity. Lysosomal photodestruction of MDR cells overexpressing the key MDR efflux transporters ABCG2, ABCB1 or ABCC1 resulted in 10- to 52-fold lower IC50 values of various IAs, thereby restoring parental cell sensitivity. Finally, in vivo application of this photodynamic therapy strategy after i.v. injection of IAs in human ovarian tumor xenografts in the chorioallantoic membrane model revealed selective destruction of tumors and their associated vasculature. These findings identify lysosomal sequestration of IAs as an Achilles heel of MDR cells that can be harnessed to eradicate MDR tumor cells via lysosomal photodestruction. PMID:22476101

  17. [Travellers and multi-drug resistance bacteria].

    PubMed

    Takeshita, Nozomi

    2012-02-01

    The number of international travellers has increased. There is enormous diversity in medical backgrounds, purposes of travel, and travelling styles among travellers. Travellers are hospitalized abroad because of exotic and common diseases via medical tourism. This is one way of transporting and importing human bacteria between countries, including multi-drug resistant organisms. In developing countries, the antimicrobial resistance in Shigella sp. and Salmonella sp. have been a problem, because of this trend, the first choice of antibiotics has changed in some countries. Community acquired infections as well as hospital acquired infections with MRSA, multi-drug resistance (MDR) Pseudomonas aeruginosa, and ESBL have been a problem. This review will discuss the risk of MDR bacterial infectious diseases for travellers.

  18. Multidrug-resistant Acinetobacter meningitis in children

    PubMed Central

    Shah, Ira; Kapdi, Muznah

    2016-01-01

    Acinetobacter species have emerged as one of the most troublesome pathogens for healthcare institutions globally. In more recent times, nosocomial infections involving the central nervous system, skin and soft tissue, and bone have emerged as highly problematic. Acinetobacter species infection is common in intensive care units; however, Acinetobacter baumannii meningitis is rarely reported. Here, we report two cases of Acinetobacter baumannii meningitis which was multidrug resistance and ultimately required the carbapenem group of drugs for the treatment.

  19. Protein arginine methyltransferase 1 may be involved in pregnane x receptor-activated overexpression of multidrug resistance 1 gene during acquired multidrug resistant

    PubMed Central

    Li, Tingting; Kong, Ah-Ng Tony; Ma, Zhiqiang; Liu, Haiyan; Liu, Pinghua; Xiao, Yu; Jiang, Xuehua; Wang, Ling

    2016-01-01

    Purpose Pregnane x receptor (PXR) - activated overexpression of the multidrug resistance 1 (MDR1) gene is an important way for tumor cells to acquire drug resistance. However, the detailed mechanism still remains unclear. In the present study, we aimed to investigate whether protein arginine methyl transferase 1(PRMT1) is involved in PXR - activated overexpression of MDR1 during acquired multidrug resistant. Experimental Design Arginine methyltransferase inhibitor 1 (AMI-1) was used to pharmacologically block PRMT1 in resistant breast cancer cells (MCF7/adr). The mRNA and protein levels of MDR1 were detected by real-time PCR and western blotting analysis. Immunofluorescence microscopy and co-immunoprecipitation were used to investigate the physical interaction between PXR and PRMT1. Then, 136 candidate compounds were screened for PRMT1 inhibitors. Lastly, luciferase reporter gene and nude mice bearing resistant breast cancer xenografts were adopted to investigate the anti-tumor effect of PRMT1 inhibitors when combined with adriamycin. Results AMI-1 significantly suppressed the expression of MDR1 in MCF7/adr cells and increased cells sensitivity of MCF7/adr to adriamycin. Physical interaction between PRMT1 and PXR exists in MCF7/adr cells, which could be disrupted by AMI-1. Those results suggest that PRMT1 may be involved in PXR-activated overexpression of MDR1 in resistant breast cancer cells, and AMI-1 may suppress MDR1 by disrupting the interaction between PRMT1 and PXR. Then, five compounds including rutin, isoquercitrin, salvianolic acid A, naproxen, and felodipline were identified to be PRMT1 inhibitors. Finally, those PRMT1 inhibitors were observed to significantly decrease MDR1 promoter activity in vitro and enhance the antitumor effect of adriamycin in nude mice that bearing resistant breast cancer xenografts. Conclusions PRMT1 may be an important co-activator of PXR in activating MDR1 gene during acquired resistance, and PRMT1 inhibitor combined with

  20. Repurposing ebselen for treatment of multidrug-resistant staphylococcal infections

    PubMed Central

    Thangamani, Shankar; Younis, Waleed; Seleem, Mohamed N.

    2015-01-01

    Novel antimicrobials and new approaches to developing them are urgently needed. Repurposing already-approved drugs with well-characterized toxicology and pharmacology is a novel way to reduce the time, cost, and risk associated with antibiotic innovation. Ebselen, an organoselenium compound, is known to be clinically safe and has a well-known pharmacology profile. It has shown potent bactericidal activity against multidrug-resistant clinical isolates of staphylococcus aureus, including methicillin- and vancomycin-resistant S. aureus (MRSA and VRSA). We demonstrated that ebselen acts through inhibition of protein synthesis and subsequently inhibited toxin production in MRSA. Additionally, ebselen was remarkably active and significantly reduced established staphylococcal biofilms. The therapeutic efficacy of ebselen was evaluated in a mouse model of staphylococcal skin infections. Ebselen 1% and 2% significantly reduced the bacterial load and the levels of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), and monocyte chemo attractant protein-1 (MCP-1) in MRSA USA300 skin lesions. Furthermore, it acts synergistically with traditional antimicrobials. This study provides evidence that ebselen has great potential for topical treatment of MRSA skin infections and lays the foundation for further analysis and development of ebselen as a potential treatment for multidrug-resistant staphylococcal infections. PMID:26111644

  1. MiR-139-5p reverses CD44+/CD133+-associated multidrug resistance by downregulating NOTCH1 in colorectal carcinoma cells

    PubMed Central

    Xu, Ke; Shen, Ke; Liang, Xin; Li, Yueqi; Nagao, Norio; Li, Jiyu; Liu, Jianwen; Yin, Peihao

    2016-01-01

    MiRNAs may promote or inhibit tumor recurrence and drug resistance. MiR-139-5p is reportedly downregulated in colorectal cancer patient samples, but it is unknown whether and how miR-139-5p regulates drug resistance. Cancer stem cells (CSCs) are postulated to be important promoters of multiple drug resistance (MDR). In this study, we established a MDR cell model which strongly expressed the CSC-associated biomarkers CD44 and CD133. MiR-139-5p expression was reduced in MDR cell lines, while overexpression of miR-139-5p reversed CD44+/CD133+-associated MDR. We also identified NOTCH1, an important protein for stem cell maintenance and function, as a direct target of miR-139-5p, both in vitro and in a knockout mouse model. Notch1 expression was upregulated in tumor samples and inversely correlated with expression of miR-139-5p. Silencing NOTCH1 exerted an effect similar to overexpression of miR-139-5p by inhibiting the CD44+ and CD133+ population and reversing the drug-resistant phenotype. In conclusion, miR-139-5p downregulated NOTCH1 signaling to reverse CD44+/CD133+-associated MDR in colorectal cancer cells. Given this insight into the miRNA regulation of MDR, miR-139-5p could be a promising therapeutic target for colorectal cancer therapy. PMID:27738333

  2. Photoexcited quantum dots for killing multidrug-resistant bacteria.

    PubMed

    Courtney, Colleen M; Goodman, Samuel M; McDaniel, Jessica A; Madinger, Nancy E; Chatterjee, Anushree; Nagpal, Prashant

    2016-05-01

    Multidrug-resistant bacterial infections are an ever-growing threat because of the shrinking arsenal of efficacious antibiotics. Metal nanoparticles can induce cell death, yet the toxicity effect is typically nonspecific. Here, we show that photoexcited quantum dots (QDs) can kill a wide range of multidrug-resistant bacterial clinical isolates, including methicillin-resistant Staphylococcus aureus, carbapenem-resistant Escherichia coli, and extended-spectrum β-lactamase-producing Klebsiella pneumoniae and Salmonella typhimurium. The killing effect is independent of material and controlled by the redox potentials of the photogenerated charge carriers, which selectively alter the cellular redox state. We also show that the QDs can be tailored to kill 92% of bacterial cells in a monoculture, and in a co-culture of E. coli and HEK 293T cells, while leaving the mammalian cells intact, or to increase bacterial proliferation. Photoexcited QDs could be used in the study of the effect of redox states on living systems, and lead to clinical phototherapy for the treatment of infections.

  3. Photoexcited quantum dots for killing multidrug-resistant bacteria

    NASA Astrophysics Data System (ADS)

    Courtney, Colleen M.; Goodman, Samuel M.; McDaniel, Jessica A.; Madinger, Nancy E.; Chatterjee, Anushree; Nagpal, Prashant

    2016-05-01

    Multidrug-resistant bacterial infections are an ever-growing threat because of the shrinking arsenal of efficacious antibiotics. Metal nanoparticles can induce cell death, yet the toxicity effect is typically nonspecific. Here, we show that photoexcited quantum dots (QDs) can kill a wide range of multidrug-resistant bacterial clinical isolates, including methicillin-resistant Staphylococcus aureus, carbapenem-resistant Escherichia coli, and extended-spectrum β-lactamase-producing Klebsiella pneumoniae and Salmonella typhimurium. The killing effect is independent of material and controlled by the redox potentials of the photogenerated charge carriers, which selectively alter the cellular redox state. We also show that the QDs can be tailored to kill 92% of bacterial cells in a monoculture, and in a co-culture of E. coli and HEK 293T cells, while leaving the mammalian cells intact, or to increase bacterial proliferation. Photoexcited QDs could be used in the study of the effect of redox states on living systems, and lead to clinical phototherapy for the treatment of infections.

  4. Increased sensitivity to anticancer drugs and decreased inflammatory response in mice lacking the multidrug resistance-associated protein.

    PubMed

    Wijnholds, J; Evers, R; van Leusden, M R; Mol, C A; Zaman, G J; Mayer, U; Beijnen, J H; van der Valk, M; Krimpenfort, P; Borst, P

    1997-11-01

    The multidrug resistance-associated protein (MRP) mediates the cellular excretion of many drugs, glutathione S-conjugates (GS-X) of lipophilic xenobiotics and endogenous cysteinyl leukotrienes. Increased MRP levels in tumor cells can cause multidrug resistance (MDR) by decreasing the intracellular drug concentration. The physiological role or roles of MRP remain ill-defined, however. We have generated MRP-deficient mice by using embryonic stem cell technology. Mice homozygous for the mrp mutant allele, mrp-/-, are viable and fertile, but their response to an inflammatory stimulus is impaired. We attribute this defect to a decreased secretion of leukotriene C4 (LTC4) from leukotriene-synthesizing cells. Moreover, the mrp-/- mice are hypersensitive to the anticancer drug etoposide. The phenotype of mrp-/- mice is consistent with a role for MRP as the main LTC4-exporter in leukotriene-synthesizing cells, and as an important drug exporter in drug-sensitive cells. Our results suggest that this ubiquitous GS-X pump is dispensable in mice, making treatment of MDR with MRP-specific reversal agents potentially feasible.

  5. Multidrug resistance in pediatric urinary tract infections.

    PubMed

    Gaspari, Romolo J; Dickson, Eric; Karlowsky, James; Doern, Gary

    2006-01-01

    Urinary tract infections (UTIs) represent a common infection in the pediatric population. Escherichia coli is the most common uropathogen in children, and antimicrobial resistance in this species complicates the treatment of pediatric UTIs. Despite the impact of resistance on empiric antibiotic choice, there is little data on multidrug resistance in pediatric patients. In this paper, we describe characteristics of multidrug-resistant E. coli in pediatric patients using a large national database of uropathogens antimicrobial sensitivities. Antimicrobial susceptibility patterns to commonly prescribed antibiotics were performed on uropathogens isolated from children presenting to participating hospitals between 1999 and 2001. Data were analyzed separately for four pediatric age groups. Single and multidrug resistance to ampicillin, amoxicillin-clavulanate, cefazolin, ciprofloxacin, nitrofurantoin, and trimethoprim-sulfamethoxazole (TMP-SMX) were performed on all specimens. There were a total of 11,341 E. coli urine cultures from 343 infants (0-4 weeks), 1,801 toddlers (5 weeks-24 months), 6,742 preteens (2-12 years), and 2,455 teens (13-17 years). E. coli resistance to ampicillin peaked in toddlers (52.8%) but was high in preteens (52.1%), infants (50.4%), and teens (40.6%). Resistance to two or more antibiotics varied across age groups, with toddlers (27%) leading preteens (23.1%), infants (21%), and teens (15.9%). Resistance to three or more antibiotics was low in all age groups (range 3.1-5.2%). The most common co-resistance in all age groups was ampicillin/TMP-SMZ. In conclusion, less than half of all pediatric UTIs are susceptible to all commonly used antibiotics. In some age groups, there is a significant percentage of co-resistance between the two most commonly used antibiotics (ampicillin and TMP-SMZ).

  6. Multidrug Resistance Protein 1 Protects the Oropharyngeal Mucosal Layer and the Testicular Tubules against Drug-induced Damage

    PubMed Central

    Wijnholds, Jan; Scheffer, George L.; van der  Valk, Martin; van der  Valk, Paul; Beijnen, Jos H.; Scheper, Rik J.; Borst, Piet

    1998-01-01

    The multidrug resistance protein 1 (MRP1) gene encodes a transporter protein that helps to protect cells against xenobiotics. Elevated levels of MRP1 in tumor cells can result in active extrusion of a wide range of (anticancer) drugs with different cellular targets, a phenomenon called multidrug resistance (MDR). To explore the protective function of the mouse mrp1 protein during drug treatment, we investigated the toxicity caused by the anticancer drug etoposide-phosphate (ETOPOPHOS) in mice lacking the mrp1 gene (mrp1−/− mice). We show here that the lack of mrp1 protein results in increased etoposide-induced damage to the mucosa of the oropharyngeal cavity and to the seminiferous tubules of the testis. The high concentrations of mrp1 that we find in the basal layers of the oropharyngeal mucosa and in the basal membrane of the Sertoli cells in the testis apparently protect wild-type mice against this tissue damage. We also find drug-induced polyuria in mrp1−/− mice, which correlates with the presence of mrp1 protein in the urinary collecting tubules, the major site of kidney water reabsorption. Our results indicate that specific inhibitors of MRP1 used to reverse MDR, in combination with carcinostatic drugs transported by MRP1, might lead to drug-induced mucositis, (temporary) infertility, and diabetes insipidus. PMID:9730882

  7. BPR1K653, a Novel Aurora Kinase Inhibitor, Exhibits Potent Anti-Proliferative Activity in MDR1 (P-gp170)-Mediated Multidrug-Resistant Cancer Cells

    PubMed Central

    Cheung, Chun Hei Antonio; Lin, Wen-Hsing; Hsu, John Tsu-An; Hour, Tzyh-Chyuan; Yeh, Teng-Kuang; Ko, Shengkai; Lien, Tzu-Wen; Coumar, Mohane Selvaraj; Liu, Jin-Fen; Lai, Wen-Yang; Shiao, Hui-Yi; Lee, Tian-Ren; Hsieh, Hsing-Pang; Chang, Jang-Yang

    2011-01-01

    Background Over-expression of Aurora kinases promotes the tumorigenesis of cells. The aim of this study was to determine the preclinical profile of a novel pan-Aurora kinase inhibitor, BPR1K653, as a candidate for anti-cancer therapy. Since expression of the drug efflux pump, MDR1, reduces the effectiveness of various chemotherapeutic compounds in human cancers, this study also aimed to determine whether the potency of BPR1K653 could be affected by the expression of MDR1 in cancer cells. Principal Findings BPR1K653 specifically inhibited the activity of Aurora-A and Aurora-B kinase at low nano-molar concentrations in vitro. Anti-proliferative activity of BPR1K653 was evaluated in various human cancer cell lines. Results of the clonogenic assay showed that BPR1K653 was potent in targeting a variety of cancer cell lines regardless of the tissue origin, p53 status, or expression of MDR1. At the cellular level, BPR1K653 induced endo-replication and subsequent apoptosis in both MDR1-negative and MDR1-positive cancer cells. Importantly, it showed potent activity against the growth of xenograft tumors of the human cervical carcinoma KB and KB-derived MDR1-positive KB-VIN10 cells in nude mice. Finally, BPR1K653 also exhibited favorable pharmacokinetic properties in rats. Conclusions and Significance BPR1K653 is a novel potent anti-cancer compound, and its potency is not affected by the expression of the multiple drug resistant protein, MDR1, in cancer cells. Therefore, BPR1K653 is a promising anti-cancer compound that has potential for the management of various malignancies, particularly for patients with MDR1-related drug resistance after prolonged chemotherapeutic treatments. PMID:21887256

  8. A plasma membrane 'vacuum cleaner' for daunorubicin in non-P-glycoprotein multidrug-resistant SW-1573 human non-small cell lung carcinoma cells. A study using fluorescence resonance energy transfer.

    PubMed

    Mülder, H S; van Grondelle, R; Westerhoff, H V; Lankelma, J

    1993-12-15

    A multidrug resistant (MDR) human non-small cell lung carcinoma cell line, SW-1573/2R120 (2R120), not containing the drug-efflux pump P-glycoprotein (PgP), has been studied for the transport of daunorubicin (DN) across the cellular plasma membrane. Earlier, reduced initial DN-uptake rates and lower cellular DN steady-state concentrations were found for this cell line, when it was compared to the SW-1573 wild-type cell line. This finding was an indication for the presence of another cellular drug-efflux pump. However, we found similar DN-efflux rates in drug-free medium for the two cell lines, while for Pgp-containing MDR SW-1573/2R160 (2R160) cells the efflux rate was increased compared to wild-type cells. In order to elucidate differences in DN transport across the cellular plasma membrane, the association of DN with plasma membranes of intact cells was investigated, using fluorescence-resonance-energy transfer. For this purpose, the plasma-membrane probe 1-(4-trimethyl-ammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH) was chosen since, because of the overlap between the emission spectrum of TMA-DPH and the excitation spectrum of DN, transfer of energy can be achieved from TMA-DPH to DN. Cells were loaded with TMA-DPH and, after addition of 10 microM DN, the TMA-DPH fluorescence was quenched. Rapid initial quenching proved to be similar in the MDR 2R160 (Pgp-containing) cells and in the SW-1573 wild-type cells (21 +/- 1% and 20 +/- 2%, respectively), but was less in the MDR 2R120 cells not containing Pgp (14 +/- 1%). This finding correlated with a lowered amount of DN dissolved in the plasma membrane of 2R120 cells. We interpret these data to be the result of a 'vacuum-cleaner' pumping system other than Pgp which removes DN from a plasma membrane compartment and equilibrates relatively slowly with the interior of the cell.

  9. Se/Ru-Decorated Porous Metal-Organic Framework Nanoparticles for The Delivery of Pooled siRNAs to Reversing Multidrug Resistance in Taxol-Resistant Breast Cancer Cells.

    PubMed

    Chen, Qingchang; Xu, Meng; Zheng, Wenjing; Xu, Taoyuan; Deng, Hong; Liu, Jie

    2017-03-01

    We report here a novel and personalized strategy of selenium/ruthenium nanoparticles modified metal organic frameworks MIL-101(Fe) for delivering pooled small interfering RNAs (siRNAs) to enhance therapy efficacy by silencing multidrug resistance (MDR) genes and interfere with microtubule (MT) dynamics in MCF-7/T (Taxol-resistance) cell. The existence of coordinatively unsaturated metal sites in MIL-101(Fe) can strongly interact with the electron-rich functional groups of cysteine, which can be regarded as the linkage between selenium/ruthenium nanoparticles and MIL-101(Fe). Se@MIL-101 and Ru@MIL-101 loaded with MDR gene-silencing siRNAs via surface coordination can significantly enhance protection of siRNAs against nuclease degradation, increase siRNA cellular uptake, and promote siRNA escape from endosomes/lysosome to silence MDR genes in MCF-7/T cell, resulting in enhanced cytotoxicity through the induction of apoptosis with the signaling pathways of phosphorylation of p53, MAPK, and PI3K/Akt and the dynamic instability of MTs and disrupting normal mitotic spindle formation. Furthermore, in vivo investigation of the nanoparticles on nude mice bearing MCF-7/T cancer xenografts confirmed that Se@MIL-101-(P+V)siRNA nanoparticles can significantly enhance cancer therapeutic efficacy and decrease systemic toxicity in vivo.

  10. [ABC transporter proteins in multidrug resistance of microorganisms].

    PubMed

    Balková, K; Gbelská, Y

    2007-08-01

    The ABC (ATP binding cassette) transporter family includes membrane proteins that can transport a wide variety of substrates across biological membranes. These proteins play an essential role in the protection of cells from toxic compounds/metabolites. Their overexpression which leads to the development of multidrug resistance (MDR) in pathogens and enables cancer cells to survive chemotherapy is of major concern for human health. Mutations in ABC transporters are implicated in a number of Mendelian disorders such as cystic fibrosis, adrenoleukodystrophy and cholesterol and bile transport defects. In microbial cells, several homologues of human ABC transporters were identified. Their further molecular biological study can contribute to better understanding and treatment of MDR or diseases caused by dysfunction of ABC transporter proteins. A review is presented of the state of the art in ABC transporter proteins in both prokaryotic and eucaryotic cells. The role of microbial ABC transporters in the development of drug resistance is analyzed.

  11. Lacidipine and josamycin: two new multidrug resistance modulators.

    PubMed

    Crosta, L; Candiloro, V; Meli, M; Tolomeo, M; Rausa, L; Dusonchet, L

    1994-01-01

    In this paper we report the results obtained treating a multidrug resistant (MDR) murine erythroleukemia cell line with daunomycin (DNM) in association with two new modulators characterized by a favourable therapeutic index, lacidipine (LCD), a dihydropyridine calcium antagonist, and josamycin (JSM), a macrolide antibiotic. LCD and JSM exhibited a greater MDR reversal activity than verapamil (VRP) and erythromycin (ERY) respectively. The accumulation of DNM in the DRTL cells exposed to modulators was similar to that of the parental cell line FLC. In the case of LCD, it was possible to ascertain that at a very low concentration this molecule can circumvent MDR without modifying DNM accumulation, suggesting that multiple different determinants may be responsible for MDR other than P-170 in this cell line.

  12. Multidrug-resistant tuberculosis in central Asia.

    PubMed

    Cox, Helen Suzanne; Orozco, Juan Daniel; Male, Roy; Ruesch-Gerdes, Sabine; Falzon, Dennis; Small, Ian; Doshetov, Darebay; Kebede, Yared; Aziz, Mohammed

    2004-05-01

    Multidrug-resistant tuberculosis (MDR-TB) has emerged as a major threat to TB control, particularly in the former Soviet Union. To determine levels of drug resistance within a directly observed treatment strategy (DOTS) program supported by Médecins Sans Frontières in two regions in Uzbekistan and Turkmenistan, Central Asia, we conducted a cross-sectional survey of smear-positive TB patients in selected districts of Karakalpakstan (Uzbekistan) and Dashoguz (Turkmenistan). High levels of MDR-TB were found in both regions. In Karakalpakstan, 14 (13%) of 106 new patients were infected with MDR-TB; 43 (40%) of 107 previously treated patients were similarly infected. The proportions for Dashoguz were 4% (4/105 patients) and 18% (18/98 patients), respectively. Overall, 27% of patients with positive smear results whose infections were treated through the DOTS program in Karakalpakstan and 11% of similar patients in Dashoguz were infected with multidrug-resistant strains of TB on admission. These results show the need for concerted action by the international community to contain transmission and reduce the effects of MDR-TB.

  13. Multidrug-resistant Tuberculosis in Central Asia

    PubMed Central

    Orozco, Juan Daniel; Male, Roy; Ruesch-Gerdes, Sabine; Falzon, Dennis; Small, Ian; Doshetov, Darebay; Kebede, Yared; Aziz, Mohammed

    2004-01-01

    Multidrug-resistant tuberculosis (MDR-TB) has emerged as a major threat to TB control, particularly in the former Soviet Union. To determine levels of drug resistance within a directly observed treatment strategy (DOTS) program supported by Médecins Sans Frontières in two regions in Uzbekistan and Turkmenistan, Central Asia, we conducted a cross-sectional survey of smear-positive TB patients in selected districts of Karakalpakstan (Uzbekistan) and Dashoguz (Turkmenistan). High levels of MDR-TB were found in both regions. In Karakalpakstan, 14 (13%) of 106 new patients were infected with MDR-TB; 43 (40%) of 107 previously treated patients were similarly infected. The proportions for Dashoguz were 4% (4/105 patients) and 18% (18/98 patients), respectively. Overall, 27% of patients with positive smear results whose infections were treated through the DOTS program in Karakalpakstan and 11% of similar patients in Dashoguz were infected with multidrug-resistant strains of TB on admission. These results show the need for concerted action by the international community to contain transmission and reduce the effects of MDR-TB. PMID:15200821

  14. Most drugs that reverse multidrug resistance also inhibit photoaffinity labeling of P-glycoprotein by a vinblastine analog

    SciTech Connect

    Akiyama, S.; Cornwell, M.M.; Kuwano, M.; Pastan, I.; Gottesman, M.M.

    1988-02-01

    Multidrug-resistant human KB carcinoma cells express a 170,000-dalton membrane glycoprotein (P-glycoprotein) that can be photoaffinity labeled with the vinblastine analog N-(p-azido-(3-/sup 125/I)salicyl)-N'-(beta-aminoethyl)vindesine. Several agents that suppress the multidrug-resistant phenotype, including N-solanesyl-N,N'-bis(3,4-dimethylbenzyl)ethylenediamine, cepharanthine, quinidine, and reserpine, were found to inhibit photolabeling of P-glycoprotein at doses comparable to those that reverse multidrug resistance. However, the phenothiazines chlorpromazine and trifluoperazine, which also effectively reverse multidrug resistance, were poor inhibitors of the photoaffinity labeling of P-glycoprotein. Chloroquine, propranolol, or atropine, which only partially reversed the drug resistance, also did not inhibit photolabeling. Naphthalene sulfonamide calmodulin inhibitors, W7 and W5, as well as many other drugs that did not circumvent multidrug resistance, did not inhibit photolabeling. These studies suggest that most, but not all, agents that phenotypically suppress multidrug resistance also inhibit drug binding to a site on P-glycoprotein with which a photoaffinity analog of vinblastine interacts.

  15. Intestinal Decontamination of Multidrug-resistant Klebsiella pneumoniae After Recurrent Infections in an Immunocompromised Host

    PubMed Central

    Kronman, Matthew P.; Zerr, Danielle M.; Qin, Xuan; Englund, Janet; Cornell, Cathy; Sanders, Jean E.; Myers, Jeffrey; Rayar, Jaipreet; Berry, Jessica E.; Adler, Amanda L.; Weissman, Scott J.

    2014-01-01

    Multidrug-resistant (MDR) Enterobacteriaceae infections are associated with increased morbidity. We describe a 20-year-old hematopoietic cell transplantation recipient with recurrent MDR Klebsiella pneumoniae infection, prolonged intestinal colonization, and subsequent intestinal decontamination. Further study should evaluate stool surveillance, molecular typing, and fecal microbiota transplantation for patients with intestinal MDR Enterobacteriaceae carriage. PMID:25041704

  16. How to Measure Export via Bacterial Multidrug Resistance Efflux Pumps

    PubMed Central

    Blair, Jessica M. A.

    2016-01-01

    ABSTRACT Bacterial multidrug resistance (MDR) efflux pumps are an important mechanism of antibiotic resistance and are required for many pathogens to cause infection. They are also being harnessed to improve microbial biotechnological processes, including biofuel production. Therefore, scientists of many specialties must be able to accurately measure efflux activity. However, myriad methodologies have been described and the most appropriate method is not always clear. Within the scientific literature, many methods are misused or data arising are misinterpreted. The methods for measuring efflux activity can be split into two groups, (i) those that directly measure efflux and (ii) those that measure the intracellular accumulation of a substrate, which is then used to infer efflux activity. Here, we review the methods for measuring efflux and explore the most recent advances in this field, including single-cell or cell-free technologies and mass spectrometry, that are being used to provide more detailed information about efflux pump activity. PMID:27381291

  17. Studies on pyrrolopyrimidines as selective inhibitors of multidrug-resistance-associated protein in multidrug resistance.

    PubMed

    Wang, Shouming; Folkes, Adrian; Chuckowree, Irina; Cockcroft, Xiaoling; Sohal, Sukhjit; Miller, Warren; Milton, John; Wren, Stephen P; Vicker, Nigel; Depledge, Paul; Scott, John; Smith, Lyndsay; Jones, Hazel; Mistry, Prakash; Faint, Richard; Thompson, Deanne; Cocks, Simon

    2004-03-11

    Multidrug resistance mediated by P-glycoprotein (Pgp) or multidrug-resistance-associated protein (MRP) remains a major obstacle for successful treatment of cancer. Inhibition of Pgp and MRP transport is important for high efficacy of anticancer drugs. While several Pgp inhibitors have entered clinical trials, the development of specific MRP1 inhibitors is still in its infancy. In our screening program, we have identified a pyrrolopyrimidine (4) as a novel and selective MRP1 inhibitor. Subsequent SAR work on the 4-position of the template revealed the phenethylpiperazine side chain as a potent replacement of the benzylthio group of the lead molecule. Introduction of groups at the 2-position seems to have no detrimental effect on activity. Modifications to the nitrile group at the 7-position resulted in the identification of analogues with groups, such as amides, with superior pharmacokinetic profiles. In vivo efficacy has been demonstrated by xenograft studies on selected compounds.

  18. Interleukin-18 Down-Regulates Multidrug Resistance-Associated Protein 2 Expression through Farnesoid X Receptor Associated with Nuclear Factor Kappa B and Yin Yang 1 in Human Hepatoma HepG2 Cells.

    PubMed

    Liu, Xiao-cong; Lian, Wei; Zhang, Liang-jun; Feng, Xin-chan; Gao, Yu; Li, Shao-xue; Liu, Chang; Cheng, Ying; Yang, Long; Wang, Xiao-Juan; Chen, Lei; Wang, Rong-quan; Chai, Jin; Chen, Wen-sheng

    2015-01-01

    Multidrug resistance-associated protein 2 (MRP2) plays an important role in bile acid metabolism by transporting toxic organic anion conjugates, including conjugated bilirubin, glutathione, sulfate, and multifarious drugs. MRP2 expression is reduced in cholestatic patients and rodents. However, the molecular mechanism of MRP2 down-regulation remains elusive. In this report, we treated human hepatoma HepG2 cells with interleukin-18 (IL-18) and measured the expression of MRP2, nuclear factor kappa B (NF-κB), farnesoid X receptor (FXR), and the transcription factor Yin Yang 1 (YY1) by quantitative real-time quantitative polymerase chain reaction (PCR) and western blotting. We found that expression of MRP2 was repressed by IL-18 at both the mRNA and protein levels in a dose- and time-dependent manner. Furthermore, the activated NF-κB pathway increased YY1 and reduced FXR. These changes were all attenuated in HepG2 cells with knockdown of the NF-κB subunit, p65. The reduced expression of FXR and MRP2 in HepG2 cells that had been caused by IL-18 treatment was also attenuated by YY1 knockdown. We further observed significantly elevated IL-18, NF-κB, and YY1 expression and decreased FXR and MRP2 expression in bile duct-ligated Sprague Dawley rat livers. Chromatin immunoprecipitation assays also showed that FXR bound to the promoter region in MRP2 was less abundant in liver extracts from bile duct-ligated rats than sham-operated rats. Our findings indicate that IL-18 down-regulates MRP2 expression through the nuclear receptor FXR in HepG2 cells, and may be mediated by NF-κB and YY1.

  19. Efflux Transport Characterization of Resveratrol Glucuronides in UDP-Glucuronosyltransferase 1A1 Transfected HeLa Cells: Application of a Cellular Pharmacokinetic Model to Decipher the Contribution of Multidrug Resistance-Associated Protein 4.

    PubMed

    Wang, Shuai; Li, Feng; Quan, Enxi; Dong, Dong; Wu, Baojian

    2016-04-01

    Resveratrol undergoes extensive metabolism to form biologically active glucuronides in humans. However, the transport mechanisms for resveratrol glucuronides are not fully established. Here, we aimed to characterize the efflux transport of resveratrol glucuronides using UGT1A1-overexpressing HeLa cells (HeLa1A1 cells), and to determine the contribution of multidrug resistance-associated protein (MRP) 4 to cellular excretion of the glucuronides. Two glucuronide isomers [i.e., resveratrol 3-O-glucuronide (R3G) and resveratrol 4'-O-glucuronide (R4'G)] were excreted into the extracellular compartment after incubation of resveratrol (1-100 μM) with HeLa1A1 cells. The excretion rate was linearly related to the level of intracellular glucuronide, indicating that glucuronide efflux was a nonsaturable process. MK-571 (a dual inhibitor of UGT1A1 and MRPs) significantly decreased the excretion rates of R3G and R4'G while increasing their intracellular levels. Likewise, short-hairpin RNA (shRNA)-mediated silencing of MRP4 caused a significant reduction in glucuronide excretion but an elevation in glucuronide accumulation. Furthermore, β-glucuronidase expressed in the cells catalyzed the hydrolysis of the glucuronides back to the parent compound. A cellular pharmacokinetic model integrating resveratrol transport/metabolism with glucuronide hydrolysis/excretion was well fitted to the experimental data, allowing derivation of the efflux rate constant values in the absence or presence of shRNA targeting MRP4. It was found that a large percentage of glucuronide excretion (43%-46%) was attributed to MRP4. In conclusion, MRP4 participated in cellular excretion of R3G and R4'G. Integration of mechanistic pharmacokinetic modeling with transporter knockdown was a useful method to derive the contribution percentage of an exporter to overall glucuronide excretion.

  20. Combined expression of multidrug resistance protein (MRP) and glutathione S-transferase P1-1 (GSTP1-1) in MCF7 cells and high level resistance to the cytotoxicities of ethacrynic acid but not oxazaphosphorines or cisplatin.

    PubMed

    Morrow, C S; Smitherman, P K; Townsend, A J

    1998-10-15

    We tested the hypothesis that combined increased expression of human glutathione S-transferase P1-1 (GSTP1-1), an enzyme that catalyzes the conjugation with glutathione of several toxic electrophiles, and the glutathione-conjugate efflux pump, multidrug resistance protein (MRP), confers high level resistance to the cytotoxicities of anticancer and other drugs. To accomplish this, we developed MCF7 breast carcinoma cell derivatives that express high levels of GSTP1-1 and MRP, alone and in combination. Parental MCF7 cells, which express no GSTP1-1 and negligible MRP, served as control cells. We found that either MRP or GSTP1-1 alone conferred significant resistance to ethacrynic acid cytotoxicity. Moreover, combined expression of GSTP1-1 and MRP conferred a high level of resistance to ethacrynic acid that was greater than resistance conferred by either protein alone. Increased MRP was also associated with modest resistance to the oxazaphosphorine compounds mafosfamide, 4-hydroxycyclophosphamide, and 4-hydroperoxycyclophosphamide. However, coordinated expression of GSTP1-1 with MRP failed to augment this modest resistance. Similarly, GSTP1-1 had no effect on the sensitivities to cisplatin of MCF7 cells regardless of MRP expression. These results establish that coordinated expression of MRP and GSTP1-1 can confer high level resistance to the cytotoxicities of some drugs, including ethacrynic acid, but that such resistance is variable and does not apply to all toxic drugs that can potentially form glutathione conjugates in either spontaneous or GSTP1-1-catalyzed reactions.

  1. Epidemiology and Treatment of Multidrug Resistant Tuberculosis

    PubMed Central

    Mitnick, Carole D.; Appleton, Sasha C.; Shin, Sonya S.

    2010-01-01

    Multidrug resistant tuberculosis is now thought to afflict between 1 and 2 million patients annually. Although significant regional variability in the distribution of disease has been recorded, surveillance data are limited by several factors. The true burden of disease is likely underestimated. Nevertheless, the estimated burden is substantial enough to warrant concerted action. A range of approaches is possible, but all appropriate interventions require scale-up of laboratories and early treatment with regimens containing a sufficient number of second-line drugs. Ambulatory treatment for most patients, and improved infection control, can facilitate scale-up with decreased risk of nosocomial transmission. Several obstacles have been considered to preclude worldwide scale-up of treatment, mostly attributable to inadequate human, drug, and financial resources. Further delays in scale-up, however, risk continued generation and transmission of resistant tuberculosis, as well as associated morbidity and mortality. PMID:18810684

  2. Breaking the Spell: Combating Multidrug Resistant 'Superbugs'.

    PubMed

    Khan, Shahper N; Khan, Asad U

    2016-01-01

    Multidrug-resistant (MDR) bacteria have become a severe threat to community wellbeing. Conventional antibiotics are getting progressively more ineffective as a consequence of resistance, making it imperative to realize improved antimicrobial options. In this review we emphasized the microorganisms primarily reported of being resistance, referred as ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacteriaceae) accentuating their capacity to "escape" from routine antimicrobial regimes. The upcoming antimicrobial agents showing great potential and can serve as alternative therapeutic options are discussed. We also provided succinct overview of two evolving technologies; specifically network pharmacology and functional genomics profiling. Furthermore, In vivo imaging techniques can provide novel targets and a real time tool for potential lead molecule assessment. The employment of such approaches at prelude of a drug development process, will enables more informed decisions on candidate drug selection and will maximize or predict therapeutic potential before clinical testing.

  3. Cytotoxicity of rhein, the active metabolite of sennoside laxatives, is reduced by multidrug resistance-associated protein 1

    PubMed Central

    van Gorkom, B A P; Timmer-Bosscha, H; de Jong, S; van der Kolk, D M; Kleibeuker, J H; de Vries, E G E

    2002-01-01

    Anthranoid laxatives, belonging to the anthraquinones as do anthracyclines, possibly increase colorectal cancer risk. Anthracyclines interfere with topoisomerase II, intercalate DNA and are substrates for P-glycoprotein and multidrug resistance-associated protein 1. P-glycoprotein and multidrug resistance-associated protein 1 protect colonic epithelial cells against xenobiotics. The aim of this study was to analyse the interference of anthranoids with these natural defence mechanisms and the direct cytotoxicity of anthranoids in cancer cell lines expressing these mechanisms in varying combinations. A cytotoxicity profile of rhein, aloe emodin and danthron was established in related cell lines exhibiting different levels of topoisomerases, multidrug resistance-associated protein 1 and P-glycoprotein. Interaction of rhein with multidrug resistance-associated protein 1 was studied by carboxy fluorescein efflux and direct cytotoxicity by apoptosis induction. Rhein was less cytotoxic in the multidrug resistance-associated protein 1 overexpressing GLC4/ADR cell line compared to GLC4. Multidrug resistance-associated protein 1 inhibition with MK571 increased rhein cytotoxicity. Carboxy fluorescein efflux was blocked by rhein. No P-glycoprotein dependent rhein efflux was observed, nor was topoisomerase II responsible for reduced toxicity. Rhein induced apoptosis but did not intercalate DNA. Aloe emodin and danthron were no substrates for MDR mechanisms. Rhein is a substrate for multidrug resistance-associated protein 1 and induces apoptosis. It could therefore render the colonic epithelium sensitive to cytotoxic agents, apart from being toxic in itself. British Journal of Cancer (2002) 86, 1494–1500. DOI: 10.1038/sj/bjc/6600255 www.bjcancer.com © 2002 Cancer Research UK PMID:11986786

  4. The leukotriene LTD4 receptor antagonist MK571 specifically modulates MRP associated multidrug resistance.

    PubMed

    Gekeler, V; Ise, W; Sanders, K H; Ulrich, W R; Beck, J

    1995-03-08

    The multidrug resistant cell lines HL60/AR and GLC4/ADR show high overexpression of the gene encoding the multidrug resistance associated protein MRP compared to their drug sensitive parental counterparts. This and the virtual absence of mdr1/P-glycoprotein gene expression was proven by a complementary DNA polymerase chain reaction (cDNA-PCR) approach. Applying a 72-hour tetrazolium based colorimetric MTT-assay we demonstrate on both MDR sublines a dose-dependent modulation of drug resistances by the leukotriene LTD4 receptor antagonist MK571. A complete reversal of vincristine resistances was achieved at final MK571 concentrations of 30 microM (HL60/AR) or 50 microM (GLC4/ADR) which by itself did not disturb cellular proliferation. The drug resistance of a mdr1/P-gp overexpressing multidrug-resistant HL60 subline, in contrast, was not significantly affected by MK571. Similar effects were seen using the glutathione (GSH) synthesis inhibitor buthionine sulfoximine (BSO). Our results point to a relationship between MRP and a conjugate transporter and identify MK571 as a new tool structure for developing modulators specific for a MRP associated multidrug resistance.

  5. Epirubicin loaded with propylene glycol liposomes significantly overcomes multidrug resistance in breast cancer.

    PubMed

    Zhao, Ying-Zheng; Dai, Dan-Dan; Lu, Cui-Tao; Chen, Li-Juan; Lin, Min; Shen, Xiao-Tong; Li, Xiao-Kun; Zhang, Ming; Jiang, Xi; Jin, Rong-Rong; Li, Xing; Lv, Hai-Feng; Cai, Lu; Huang, Pin-Tong

    2013-03-01

    Multidrug resistance (MDR) is one of the major reasons for the failure of cancer chemotherapy. A newly reported liposome carrier, propylene glycol liposomes (EPI-PG-liposomes) were made to load epirubicin (EPI) which enhanced EPI absorption in MDR tumor cells to overcome the drug resistance. MDA-MB 435 and their mutant resistant (MDA-MB 435/ADR) cells were used to examine the cellular uptake and P-gp function in vitro for EPI-PG-liposomes by fluorescence microscopy and FCM, respectively. Mammary tumor model was also established to investigate the tumor growth inhibition and pharmacodynamics of EPI-PG-liposomes in vivo. Morphology evaluation showed that EPI-PG-liposomes had a homogeneous spherical shape with an average diameter of 182 nm. Based on cell viability assay, fluorescent microscopy examination, and EPI uptake assay, EPI-PG-liposomes exhibited an effective growth inhibition not only in MDA-MB-435 cells, but also in MDA-MB 435/ADR cells. EPI-PG-liposomes have high permeability not only on tumor cell membrane, but also on cell nucleus membrane. P-gp function assay showed that the anticancer action of EPI-PG-liposomes was not related to P-gp efflux pump, suggesting that PG-liposomes would not affect the normal physiological functions of membrane proteins. EPI-PG-liposomes also showed a better antitumor efficacy compared to EPI solution alone. With high entrapment efficiency, spherical morphology and effective inhibition on MDR cancer cells, EPI-PG-liposomes may represent a better chemotherapeutic vectors for cancer targeted therapy.

  6. Enhanced glutathione depletion, protein adduct formation, and cytotoxicity following exposure to 4-hydroxy-2-nonenal (HNE) in cells expressing human multidrug resistance protein-1 (MRP1) together with human glutathione S-transferase-M1 (GSTM1)

    PubMed Central

    Rudd, Lisa P.; Kabler, Sandra L.; Morrow, Charles S.; Townsend, Alan J.

    2011-01-01

    4-hydroxy-2-nonenal (HNE) is one of the most reactive products of lipid peroxidation and has both cytotoxic and genotoxic effects in cells. Several enzymatic pathways have been reported to detoxify HNE, including conjugation by glutathione-S-transferases (GSTs). Removal of the resulting HNE-glutathione conjugate (HNE-SG) by an efflux transporter may required for complete detoxification. We investigated the effect of expression of GSTM1 and/or the ABC efflux transporter protein, multidrug-resistance protein-1 (MRP1), on HNE-induced cellular toxicity. Stably transfected MCF7 cell lines were used to examine the effect of GSTM1 and/or MRP1 expression on HNE-induced cytotoxicity, GSH depletion, and HNE-protein adduct formation. Co-expression in the MCF7 cell line of GSTM1 with MRP1 resulted in a 2.3-fold sensitization to HNE cytotoxicity (0.44-fold IC50 value relative to control) rather than the expected protection. Expression of either GSTM1 or MRP1 alone also resulted in slight sensitization to HNE cytotoxicity (0.79-fold and 0.71-fold decreases in IC50 values, respectively). Co-expression of GSTM1 and MRP1 strongly enhanced the formation of HNE-protein adducts relative to the non-expressing control cell line, whereas expression of either MRP1 alone or GSTM1 alone yielded similarly low levels of HNE-protein adducts to that of the control cell line. Glutathione (GSH) levels were reduced by 10–20% in either the control cell line or the MCF7/GSTM1 cell line with the same HNE exposure for 60 minutes. However, HNE induced > 80% depletion of GSH in cells expressing MRP1 alone. Co-expression of both MRP1 and GSTM1 caused slightly greater GSH depletion, consistent with the greater protein adduct formation and cytotoxicity in this cell line. Since expression of GSTM1 or MRP1 alone did not strongly sensitize cells to HNE, or result in greater HNE-protein adducts than in the control cell line, these results indicate that MRP1 and GSTM1 collaborate to enhance HNE-protein adduct

  7. Characterization of multidrug resistance P-glycoprotein transport function with an organotechnetium cation

    SciTech Connect

    Piwnica-Worms, D.; Vallabhaneni, V.R.; Kronauge, J.F.

    1995-09-26

    Multidrug resistance (MDR) in mammalian cells and tumors is associated with overexpression of an {approximately}170 integral membrane efflux transporter, the MDR1 P-glycoprotein. Hexakis(2-methoxyisobutyl isonitrile) technetium(I) (Tc-SESTAMIBI), a {gamma}-emitting lipophilic cationic metallopharmaceutical, has recently been shown to be a P-glycoprotein transport substrate. Exploiting the negligible lipid membrane adsorption properties of this organometallic substrate, we studied the transport kinetics, pharmacology, drug binding, and modulation of P-glycoprotein in cell preparations derived from a variety of species and selection strategies, including SW-1573, V79, Alex, and CHO drug-sensitive cells and in 77A, LZ-8, and Alex/A.5 MDR cells. Rapid cell accumulation (T{sub 1/2} {approx} 6 min) of the agent to a steady state was observed which was inversely proportional to immunodetectable levels of P-glycoprotein. Many MDR cytotoxic agents inhibited P-glycoprotein-mediated Tc-SESTAMIBI efflux, thereby enhancing organometallic cation accumulation. 70 refs., 7 figs., 2 tabs.

  8. Bacillus subtilis from Soybean Food Shows Antimicrobial Activity for Multidrug-Resistant Acinetobacter baumannii by Affecting the adeS Gene.

    PubMed

    Wang, Tieshan; Su, Jianrong

    2016-12-28

    Exploring novel antibiotics is necessary for multidrug-resistant pathogenic bacteria. Because the probiotics in soybean food have antimicrobial activities, we investigated their effects on multidrug-resistant Acinetobacter baumannii. Nineteen multidrug-resistant A. baumannii strains were clinifcally isolated as an experimental group and 11 multidrug-sensitive strains as controls. The growth rates of all bacteria were determined by using the analysis for xCELLigence Real-Time Cell. The combination of antibiotics showed synergistic effects on the strains in the control group but no effect on the strains in the experimental group. Efflux pump gene adeS was absent in all the strains from the control group, whereas it exists in all the strains from the experimental group. Furthermore, all the strains lost multidrug resistance when an adeS inhibitor was used. One strain of probiotics isolated from soybean food showed high antimicrobial activity for multidrug-resistant A. baumannii. The isolated strain belongs to Bacillus subtilis according to 16S RNA analysis. Furthermore, E. coli showed multidrug resistance when it was transformed with the adeS gene from A. baumannii whereas the resistant bacteria could be inhibited completely by isolated Bacillus subtilis. Thus, probiotics from soybean food provide potential antibiotics against multidrug-resistant pathogenic bacteria.

  9. Uptake of compounds that selectively kill multidrug-resistant cells: the copper transporter SLC31A1 (CTR1) increases cellular accumulation of the thiosemicarbazone NSC73306.

    PubMed

    Fung, King Leung; Tepede, Abisola K; Pluchino, Kristen M; Pouliot, Lynn M; Pixley, Jessica N; Hall, Matthew D; Gottesman, Michael M

    2014-08-04

    Acquired drug resistance in cancer continues to be a challenge in cancer therapy, in part due to overexpression of the drug efflux transporter P-glycoprotein (P-gp, MDR1, ABCB1). NSC73306 is a thiosemicarbazone compound that displays greater toxicity against cells expressing functional P-gp than against other cells. Here, we investigate the cellular uptake of NSC73306, and examine its interaction with P-gp and copper transporter 1 (CTR1, SLC31A1). Overexpression of P-gp sensitizes LLC-PK1 cells to NSC73306. Cisplatin (IC50 = 77 μM), cyclosporin A (IC50 = 500 μM), and verapamil (IC50 = 700 μM) inhibited cellular accumulation of [(3)H]NSC73306. Cellular hypertoxicity of NSC73306 to P-gp-expressing cells was inhibited by cisplatin in a dose-dependent manner. Cells transiently expressing the cisplatin uptake transporter CTR1 (SLC31A1) showed increased [(3)H]NSC73306 accumulation. In contrast, CTR1 knockdown decreased [(3)H]NSC73306 accumulation. The presence of NSC73306 reduced CTR1 levels, similar to the negative feedback of CTR1 levels by copper or cisplatin. Surprisingly, although cisplatin is a substrate of CTR1, we found that CTR1 protein was overexpressed in high-level cisplatin-resistant KB-CP20 and BEL7404-CP20 cell lines. We confirmed that the CTR1 protein was functional, as uptake of NSC73306 was increased in KB-CP20 cells compared to their drug-sensitive parental cells, and downregulation of CTR1 in KB-CP20 cells reduced [(3)H]NSC73306 accumulation. These results suggest that NSC73306 is a transport substrate of CTR1.

  10. Folate-mediated mitochondrial targeting with doxorubicin-polyrotaxane nanoparticles overcomes multidrug resistance

    PubMed Central

    Yan, Fengjiao; Sun, Mingna; Du, Lingran; Peng, Wei; Li, Qiuli; Feng, Yinghong; Zhou, Yi

    2015-01-01

    Resistance to treatment with anticancer drugs is a significant obstacle and a fundamental cause of therapeutic failure in cancer therapy. Functional doxorubicin (DOX) nanoparticles for targeted delivery of the classical cytotoxic anticancer drug DOX to tumor cells, using folate-terminated polyrotaxanes along with dequalinium, have been developed and proven to overcome this resistance due to specific molecular features, including a size of approximately 101 nm, a zeta potential of 3.25 mV and drug-loading content of 18%. Compared with free DOX, DOX hydrochloride, DOX nanoparticles, and targeted DOX nanoparticles, the functional DOX nanoparticles exhibited the strongest anticancer efficacy in vitro and in the drug-resistant MCF-7/ Adr (DOX) xenograft tumor model. More specifically, the nanoparticles significantly increased the intracellular uptake of DOX, selectively accumulating in mitochondria and the endoplasmic reticulum after treatment, with release of cytochrome C as a result. Furthermore, the caspase-9 and caspase-3 cascade was activated by the functional DOX nanoparticles through upregulation of the pro-apoptotic proteins Bax and Bid and suppression of the antiapoptotic protein Bcl-2, thereby enhancing apoptosis by acting on the mitochondrial signaling pathways. In conclusion, functional DOX nanoparticles may provide a strategy for increasing the solubility of DOX and overcoming multidrug-resistant cancers. PMID:25605018

  11. Multiwavelength videomicrofluorometry for multiparametric investigations of multidrug resistance

    NASA Astrophysics Data System (ADS)

    Rocchi, Emmanuelle; Salmon, Jean-Marie; Vigo, Jean; Viallet, Pierre M.

    1996-05-01

    A major problem in the cancer chemotherapy is the development of resistance to a whole range of drugs not only similar to the drugs used for resistance induction but also to some functionally and structurally unrelated. It's one of the multifactorial causes of failure of chemotherapy. Thus it appears essential to evaluate the multi-drug resistance (MDR) in living cells populations to: detect the MDR phenotype, to discriminate between resistant and sensitive cells, to identify mechanisms which are involved in the induction or the reversion of resistance and to study the cytotoxic process. Such a challenge implies the use of multiparametric approach that has been possible using a protocol involving microfluorometry connected to numerical image analysis on single living cells. This protocol relays on the correlation existing between the decreased intracellular accumulation of some fluorescent probes such as Hoechst 33342 (Ho342) and Rhodamine 123 (R123) in resistant cells. The simultaneous estimation of the fluorescence intensities of these probes has required the use of a third probe, the Nile Red, for cell contour delineation. The analysis of parameters related to Ho342 and R123 allows the discrimination of sensitive and resistant cells. So the multiparametric approach using multi-wavelength image analysis, which appears to be a powerful technique, has allowed us to show on human lymphoblastoid CCRF-CEM cells lines that the cytotoxic effects could be different depending on the cell resistance or on the cytotoxic drug used: Adriamycine, Vinblastine and the different cell behavior could be used for cell differentiation.

  12. Modulating cancer multidrug resistance by sertraline in combination with a nanomedicine.

    PubMed

    Drinberg, Velthe; Bitcover, Rivka; Rajchenbach, Wolf; Peer, Dan

    2014-11-28

    Inherent and acquired multiple drug resistance (MDR) to chemotherapeutic drugs is a major obstacle in cancer treatment. The ATP Binding Cassettes (ABC) transporter super family that act as extrusion pumps such as P-glycoprotein and multidrug-resistance-associated-proteins have prominent roles in cancer MDR. One of the most efficient strategies to modulate this active drug efflux from the cells is to physically block the pump proteins and thus change the balance between drug influx and efflux toward an accumulation of drug inside the cell, which eventually cumulates into cell death. MDR modulators (also known as chemosensitizers) were found among drugs approved for non-cancer indications. Yet, toxicity, adverse effects, and poor solubility at doses required for MDR reversal prevent their clinical application. Previous reports have shown that drugs belonging to the selective serotonin reuptake inhibitors (SSRI) family, which are clinically used as antidepressants, can act as effective chemosensitizers both in vitro and in vivo in tumor bearing mouse models. Here, we set out to explore whether sertraline (Zoloft®), a molecule belonging to the SSRI family, can be used as an MDR modulator. Combining sertraline with another FDA approved drug, Doxil® (pegylated liposomal doxorubicin), is expected to enhance the effect of chemotherapy while potentially reducing adverse effects. Our findings reveal that sertraline acts as a pump modulator in cellular models of MDR. In addition, in an aggressive and highly resistant human ovarian xenograft mouse model the use of sertraline in combination with Doxil® generated substantial reduction in tumor progression, with extension of the median survival of tumor-bearing mice. Taken together, our results show that sertraline could act as a clinically relevant cancer MDR inhibitor. Moreover, combining two FDA approved drugs, DOXIL®, which favor the influx of chemotherapy inside the malignant cell with sertraline, which blocks the

  13. Antimicrobial Organometallic Dendrimers with Tunable Activity against Multidrug-Resistant Bacteria.

    PubMed

    Abd-El-Aziz, Alaa S; Agatemor, Christian; Etkin, Nola; Overy, David P; Lanteigne, Martin; McQuillan, Katherine; Kerr, Russell G

    2015-11-09

    Multidrug-resistant pathogens are an increasing threat to public health. In an effort to curb the virulence of these pathogens, new antimicrobial agents are sought. Here we report a new class of antimicrobial organometallic dendrimers with tunable activity against multidrug-resistant Gram-positive bacteria that included methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. Mechanistically, these redox-active, cationic organometallic dendrimers induced oxidative stress on bacteria and also disrupted the microbial cell membrane. The minimum inhibitory concentrations, which provide a quantitative measure of the antimicrobial activity of these dendrimers, were in the low micromolar range. AlamarBlue cell viability assay also confirms the antimicrobial activity of these dendrimers. Interestingly, these dendrimers were noncytotoxic to epidermal cell lines and to mammalian red blood cells, making them potential antimicrobial platforms for topical applications.

  14. Management of multidrug resistant bacterial endemic.

    PubMed

    Zahar, J-R; Lesprit, P

    2014-09-01

    The fight against multi-drug resistant Gram-negative bacilli (MDRGNB), especially extended-spectrum β-lactamase producing Enterobacteriaceae, is about to be lost in our country. The emergence of new resistance mechanisms to carbapenems in these Enterobacteriaceae exposes patients to a risk of treatment failure without any other therapeutic options. This dramatic situation is paradoxical because we are well aware of the 2 major factors responsible for this situation: 1) MDRO cross-transmission, associated with a low compliance to standard precautions, especially hand hygiene, and 2) overexposure of patients to antibiotics. The implementation of a "search and isolate" policy, which was justified to control the spread of some MDRO that remained rare in the country, was not associated with a better adherence to standard precautions. The antibiotic policy and the measures implemented to control antibiotic consumptions have rarely been enforced and have shown inconsistent results. Notably, no significant decrease of antibiotic consumption has been observed. There is no excuse for these poor results, because some authors evaluating the effectiveness of programs for the control of MDRO have reported their positive effects on antimicrobial resistance without any detrimental effects. It is now urgent to deal with the 2 major factors by establishing an educational and persuasive program with quantified and opposable objectives. Firstly, we have to improve the observance of hand hygiene above 70%. Secondly, we have to define and reach a target for the reduction of antibiotic consumption both in community and in hospital settings.

  15. [Management of multidrug-resistant tuberculosis].

    PubMed

    Tritar, F; Daghfous, H; Ben Saad, S; Slim-Saidi, L

    2015-01-01

    The emergence of drug-resistant TB in many countries has become a major public health problem and an obstacle to effective tuberculosis control. Multidrug-resistant tuberculosis (MDR-TB), which is most often the result of poor adherence, is a particularly dangerous form of tuberculosis because it is caused by bacilli resistant to at least isoniazid and rifampicin, the two most effective anti-tuberculosis drugs. Techniques for rapid diagnosis of resistance have greatly improved the care of patients by allowing early treatment which remains complex and costly establishment, and requires skills and resources. The treatment is not standardized but it includes in all cases attack phase with five drugs (there must be an injectable agent and a fluoroquinolone that form the basis of the regimen) for eight months and a maintenance phase (without injectable agent) with a total duration of 20 months on average. Surgery may be beneficial as long as the lesions are localized and the patient has a good cardiorespiratory function. Evolution of MDR-TB treated is less favorable than tuberculosis with germ sensitive. The cure rate varies from 60 to 75% for MDR-TB, and drops to 30 to 40% for XDR-TB. Mortality remains high, ranging from 20 to 40% even up to 70-90% in people co-infected with HIV.

  16. Dual Role of cAMP in the Transcriptional Regulation of Multidrug Resistance-Associated Protein 4 (MRP4) in Pancreatic Adenocarcinoma Cell Lines

    PubMed Central

    Carozzo, Alejandro; Diez, Federico; Gomez, Natalia; Cabrera, Maia; Shayo, Carina; Davio, Carlos; Fernández, Natalia

    2015-01-01

    Cyclic AMP represents one of the most studied signaling molecules and its role in proliferation and differentiation processes has been well established. Intracellular cAMP levels are tightly regulated where the MRP4 transporter plays a major role. In the present study, we sought to establish whether cAMP modulated MRP4 expression in pancreatic adenocarcinoma cell lines. Quantitative PCR and western blot studies showed that cAMP-increasing agents enhanced MRP4 transcripts and protein levels in PANC-1 cells. Reporter luciferase experiments carried out in pancreatic AR42J cells showed that intracellular cAMP up-regulates MRP4 through an Epac2- and Rap1- mediated mechanism whereas extracellular cAMP reduced MRP4 promoter activity by a MEK/ERK-mediated pathway. Present results show that cAMP regulates MRP4 promoter activity, and further indicate that the balance between intracellular and extracellular cAMP levels determines MRP4 expression. PMID:25790437

  17. Yu Ping Feng San reverses cisplatin-induced multi-drug resistance in lung cancer cells via regulating drug transporters and p62/TRAF6 signalling

    PubMed Central

    Lou, Jian-Shu; Yan, Lu; Bi, Cathy W. C.; Chan, Gallant K. L.; Wu, Qi-Yun; Liu, Yun-Le; Huang, Yun; Yao, Ping; Du, Crystal Y. Q.; Dong, Tina T. X.; Tsim, Karl W. K.

    2016-01-01

    Yu Ping Feng San (YPFS), an ancient Chinese herbal decoction composed of Astragali Radix, Atractylodis Macrocephalae Rhizoma and Saposhnikoviae Radix, has been used in the clinic for treating immune deficiency. In cancer therapy, YPFS is being combined with chemotherapy drugs to achieve improved efficacy; however, scientific evidence to illustrate this combination effect is lacking. The present study aims to demonstrate the anti-drug resistance of YPFS in cisplatin (DDP)-resistant non-small cell lung cancer cells (A549/DDP). The application of YPFS exhibited a synergistic enhancement of DDP-induced cytotoxicity as well as of the apoptotic signalling molecules. DDP-induced expression of the multi-drug-resistance efflux transporters was markedly reduced in the presence of YPFS, resulting in a higher intracellular concentration of DDP. In addition, the application of YPFS increased DDP-induced ROS accumulation and MMP depletion, decreased p62/TRAF6 signalling in DDP-treated A549/DDP cells. The co-treatment of DDP and YPFS in tumour-bearing mice reduced the tumour size robustly (by more than 80%), which was much better than the effect of DDP alone. These results indicate that YPFS can notably improve the DDP-suppressed cancer effect, which may be a consequence of the elevation of intracellular DDP via the drug transporters as well as the down regulation of p62/TRAF6 signalling. PMID:27558312

  18. Grape seed procyanidin reversal of p-glycoprotein associated multi-drug resistance via down-regulation of NF-κB and MAPK/ERK mediated YB-1 activity in A2780/T cells.

    PubMed

    Zhao, Bo-xin; Sun, Ya-bin; Wang, Sheng-qi; Duan, Lian; Huo, Qi-lu; Ren, Fei; Li, Guo-feng

    2013-01-01

    The expression and function of P-glycoprotein (P-gp) is associated with the phenotype of multi-drug resistance (MDR), leading chemotherapy failure of patients suffered with cancer. Grape seed procyanidin(GSP) is a natural polyphenol supplement with anti-inflammatory effect. Present study assessed a new use of GSP on the MDR reversal activity and its possible molecular mechanisms in MDR1-overpressing paclitaxel resistant ovarian cancer cells. Our results showed GSP significantly enhanced the cytotoxicity of paclitaxel and adriamycin in paclitaxel resistant A2780/T cells but its parental A2780 cells. Furthermore, GSP strongly inhibited P-gp expression by blocking MDR1 gene transcription, as well as, increased the intracellular accumulation of the P-gp substrate rhodamine-123 in A2780/T cells. Nuclear factor-κB(NF-κB) activity, IκB degradation level and NF-κB/p65 nuclear translocation induced by lipopolysaccharide (LPS) and receptor activator for nuclear factor-κB ligand (RANKL) were markedly inhibited by pre-treatment with GSP. Meanwhile, GSP inhibited MAPK/ERK pathway by decreasing the phosphorylation of ERK1/2, resulting in reduced the Y-box binding protein 1 (YB-1) activation with blocking its nuclear translocation. Moreover, the up-regulation of P-gp expression, the activation of AKT/NF-κB and MAPK/ERK pathway induced by LPS was attenuated by GSP administration. Compared with PDTC and U1026, inhibitor of NF-κB and MAPK/ERK respectively, GSP showed the same tendency of down-regulating NF-κB and MAPK/ERK mediated YB-1 activities. Thus, GSP reverses P-gp associated MDR by inhibiting the function and expression of P-gp through down-regulation of NF-κB activity and MAPK/ERK pathway mediated YB-1 nuclear translocation, offering insight into the mechanism of reversing MDR by natural polyphenol supplement compounds. GSP could be a new potential MDR reversal agent used for combination therapy with chemotherapeutics in clinic.

  19. Inhibition of the Multidrug Resistance P-Glycoprotein: Time for a Change of Strategy?

    PubMed Central

    Luk, Frederick; Bebawy, Mary

    2014-01-01

    P-glycoprotein (P-gp) is a key player in the multidrug-resistant phenotype in cancer. The protein confers resistance by mediating the ATP-dependent efflux of an astonishing array of anticancer drugs. Its broad specificity has been the subject of numerous attempts to inhibit the protein and restore the efficacy of anticancer drugs. The general strategy has been to develop compounds that either compete with anticancer drugs for transport or act as direct inhibitors of P-gp. Despite considerable in vitro success, there are no compounds currently available to “block” P-gp–mediated resistance in the clinic. The failure may be attributed to toxicity, adverse drug interaction, and numerous pharmacokinetic issues. This review provides a description of several alternative approaches to overcome the activity of P-gp in drug-resistant cells. These include 1) drugs that specifically target resistant cells, 2) novel nanotechnologies to provide high-dose, targeted delivery of anticancer drugs, 3) compounds that interfere with nongenomic transfer of resistance, and 4) approaches to reduce the expression of P-gp within tumors. Such approaches have been developed through the pursuit of greater understanding of resistance mediators such as P-gp, and they show considerable potential for further application. PMID:24492893

  20. Targeting Protein Kinases to Reverse Multidrug Resistance in Sarcoma

    PubMed Central

    Chen, Hua; Shen, Jacson; Choy, Edwin; Hornicek, Francis J.; Duan, Zhenfeng

    2015-01-01

    Sarcomas are a group of cancers that arise from transformed cells of mesenchymal origin. They can be classified into over 50 subtypes, accounting for approximately 1% of adult and 15% of pediatric cancers. Wide surgical resection, radiotherapy, and chemotherapy are the most common treatments for the majority of sarcomas. Among these therapies, chemotherapy can palliate symptoms and prolong life for some sarcoma patients. However, sarcoma cells can have intrinsic or acquired resistance after treatment with chemotherapeutics drugs, leading to the development of multidrug resistance (MDR). MDR attenuates the efficacy of anticancer drugs and results in treatment failure for sarcomas. Therefore, overcoming MDR is an unmet need for sarcoma therapy. Certain protein kinases demonstrate aberrant expression and/or activity in sarcoma cells, which have been found to be involved in the regulation of sarcoma cell progression, such as cell cycle, apoptosis, and survival. Inhibiting these protein kinases may not only decrease the proliferation and growth of sarcoma cells, but also reverse their resistance to chemotherapeutic drugs to subsequently reduce the doses of anticancer drugs and decrease drug side-effects. The discovery of novel strategies targeting protein kinases opens a door to a new area of sarcoma research and provides insight into the mechanisms of MDR in chemotherapy. This review will focus on the recent studies in targeting protein kinase to reverse chemotherapeutic drug resistance in sarcoma. PMID:26827688

  1. Membrane fluidization by ether, other anesthetics, and certain agents abolishes P-glycoprotein ATPase activity and modulates efflux from multidrug-resistant cells.

    PubMed

    Regev, R; Assaraf, Y G; Eytan, G D

    1999-01-01

    The anesthetics benzyl alcohol and the nonaromatic chloroform and diethyl ether, abolish P-glycoprotein (Pgp) ATPase activity in a mode that does not fit classical competitive, noncompetitive, or uncompetitive inhibition. At concentrations similar to those required for inhibition of ATPase activity, these anesthetics fluidize membranes leading to twofold acceleration of doxorubicin flip-flop across lipid membranes and prevent photoaffinity labeling of Pgp with [125I]-iodoarylazidoprazosin. Similar concentrations of ether proved nontoxic and modulated efflux from Pgp-overexpressing cells. A similar twofold acceleration of doxorubicin flip-flop rate across membranes was observed with neutral mild detergents, including Tween 20, Nonidet P-40 and Triton X-100, and certain Pgp modulators, such as verapamil and progesterone. Concentrations of these agents, similar to those required for membrane fluidization, inhibited Pgp ATPase activity in a mode similar to that observed with the anesthetics. The mode of inhibition, i.e. lack of evidence for classical enzyme inhibition and the correlation of Pgp ATPase inhibition with membrane fluidization over a wide range of concentrations and structures of drugs favors the direct inhibition of Pgp ATPase activity by membrane fluidization. The unusual sensitivity of Pgp to membrane fluidization, as opposed to acceleration of ATPase activity of ion transporters, could fit the proposed function of Pgp as a 'flippase', which is in close contact with the membrane core.

  2. Molecular mechanism of ATP-dependent solute transport by multidrug resistance-associated protein 1.

    PubMed

    Chang, Xiu-bao

    2010-01-01

    Millions of new cancer patients are diagnosed each year and over half of these patients die from this devastating disease. Thus, cancer causes a major public health problem worldwide. Chemotherapy remains the principal mode to treat many metastatic cancers. However, occurrence of cellular multidrug resistance (MDR) prevents efficient killing of cancer cells, leading to chemotherapeutic treatment failure. Over-expression of ATP-binding cassette transporters, such as P-glycoprotein, breast cancer resistance protein and/or multidrug resistance-associated protein 1 (MRP1), confers an acquired MDR due to their capabilities of transporting a broad range of chemically diverse anticancer drugs across the cell membrane barrier. In this review, the molecular mechanism of ATP-dependent solute transport by MRP1 will be addressed.

  3. Salvage therapy for multidrug-resistant tuberculosis.

    PubMed

    Seung, K J; Becerra, M C; Atwood, S S; Alcántara, F; Bonilla, C A; Mitnick, C D

    2014-05-01

    Treatment of multidrug-resistant tuberculosis (MDR-TB), defined as Mycobacterium tuberculosis resistant to both isoniazid and rifampicin, is challenging under the best of circumstances, and particularly in resource-limited settings. For patients who remain persistently sputum-culture-positive despite therapy with second-line TB drugs, treatment options are limited, especially if disease is too advanced for resective surgery. Salvage therapy refers to the design of a regimen combining new and previously used drugs in a final effort to attain sputum conversion before declaring treatment to have failed. We retrospectively evaluated the outcomes of salvage therapy in 213 Peruvian patients. Salvage regimens included a median of two new drugs (range 1-6) and nine (range 5-13) total (new plus previously used) drugs. The most frequently used new drug was moxifloxacin, followed by capreomycin, amoxicillin-clavulanate, kanamycin and clarithromycin. Culture conversion occurred in 65 (30.5%) patients. Salvage regimens that included moxifloxacin were significantly more likely to be followed by culture conversion (OR 2.2; p 0.02). Later-generation fluoroquinolones such as moxifloxacin should be used in salvage therapy but also in the initial treatment of MDR-TB, if the best clinical strategy is to use the most effective drugs when the patient has the best chance for cure. New TB drugs are most likely to be initially used in salvage patients, in conditions similar to those described here. Close bacteriological monitoring of these patients will be essential, as useful information about the best way to use these new drugs can be gained from analysis of salvage therapy cohorts.

  4. Paclitaxel-loaded star-shaped copolymer nanoparticles for enhanced malignant melanoma chemotherapy against multidrug resistance.

    PubMed

    Su, Yongsheng; Hu, Jian; Huang, Zhibin; Huang, Yubin; Peng, Bingsheng; Xie, Ni; Liu, Hui

    2017-01-01

    Malignant melanoma (MM) is the most dangerous type of skin cancer with annually increasing incidence and death rates. However, chemotherapy for MM is restricted by low topical drug concentration and multidrug resistance. In order to surmount the limitation and to enhance the therapeutic effect on MM, a new nanoformulation of paclitaxel (PTX)-loaded cholic acid (CA)-functionalized star-shaped poly(lactide-co-glycolide) (PLGA)-D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) nanoparticles (NPs) (shortly PTX-loaded CA-PLGA-TPGS NPs) was fabricated by a modified method of nanoprecipitation. The particle size, zeta potential, morphology, drug release profile, drug encapsulation efficiency, and loading content of PTX-loaded NPs were detected. As shown by confocal laser scanning, NPs loaded with coumarin-6 were internalized by human melanoma cell line A875. The cellular uptake efficiency of CA-PLGA-TPGS NPs was higher than those of PLGA NPs and PLGA-TPGS NPs. The antitumor effects of PTX-loaded NPs were evaluated by the MTT assay in vitro and by a xenograft tumor model in vivo, demonstrating that star-shaped PTX-loaded CA-PLGA-TPGS NPs were significantly superior to commercial PTX formulation Taxol(®). Such drug delivery nanocarriers are potentially applicable to the improvement of clinical MM therapy.

  5. Paclitaxel-loaded star-shaped copolymer nanoparticles for enhanced malignant melanoma chemotherapy against multidrug resistance

    PubMed Central

    Su, Yongsheng; Hu, Jian; Huang, Zhibin; Huang, Yubin; Peng, Bingsheng; Xie, Ni; Liu, Hui

    2017-01-01

    Malignant melanoma (MM) is the most dangerous type of skin cancer with annually increasing incidence and death rates. However, chemotherapy for MM is restricted by low topical drug concentration and multidrug resistance. In order to surmount the limitation and to enhance the therapeutic effect on MM, a new nanoformulation of paclitaxel (PTX)-loaded cholic acid (CA)-functionalized star-shaped poly(lactide-co-glycolide) (PLGA)-D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) nanoparticles (NPs) (shortly PTX-loaded CA-PLGA-TPGS NPs) was fabricated by a modified method of nanoprecipitation. The particle size, zeta potential, morphology, drug release profile, drug encapsulation efficiency, and loading content of PTX-loaded NPs were detected. As shown by confocal laser scanning, NPs loaded with coumarin-6 were internalized by human melanoma cell line A875. The cellular uptake efficiency of CA-PLGA-TPGS NPs was higher than those of PLGA NPs and PLGA-TPGS NPs. The antitumor effects of PTX-loaded NPs were evaluated by the MTT assay in vitro and by a xenograft tumor model in vivo, demonstrating that star-shaped PTX-loaded CA-PLGA-TPGS NPs were significantly superior to commercial PTX formulation Taxol®. Such drug delivery nanocarriers are potentially applicable to the improvement of clinical MM therapy. PMID:28293102

  6. Antimicrobial metallopolymers and their bioconjugates with conventional antibiotics against multidrug-resistant bacteria.

    PubMed

    Zhang, Jiuyang; Chen, Yung Pin; Miller, Kristen P; Ganewatta, Mitra S; Bam, Marpe; Yan, Yi; Nagarkatti, Mitzi; Decho, Alan W; Tang, Chuanbing

    2014-04-02

    Bacteria are now becoming more resistant to most conventional antibiotics. Methicillin-resistant Staphylococcus aureus (MRSA), a complex of multidrug-resistant Gram-positive bacterial strains, has proven especially problematic in both hospital and community settings by deactivating conventional β-lactam antibiotics, including penicillins, cephalosporins, and carbapenems, through various mechanisms, resulting in increased mortality rates and hospitalization costs. Here we introduce a class of charged metallopolymers that exhibit synergistic effects against MRSA by efficiently inhibiting activity of β-lactamase and effectively lysing bacterial cells. Various conventional β-lactam antibiotics, including penicillin-G, amoxicillin, ampicillin, and cefazolin, are protected from β-lactamase hydrolysis via the formation of unique ion-pairs between their carboxylate anions and cationic cobaltocenium moieties. These discoveries could provide a new pathway for designing macromolecular scaffolds to regenerate vitality of conventional antibiotics to kill multidrug-resistant bacteria and superbugs.

  7. Inorganic Nanocarriers Overcoming Multidrug Resistance for Cancer Theranostics

    PubMed Central

    Lin, Gan; Mi, Peng; Chu, Chengchao; Zhang, Jun

    2016-01-01

    Cancer multidrug resistance (MDR) could lead to therapeutic failure of chemotherapy and radiotherapy, and has become one of the main obstacles to successful cancer treatment. Some advanced drug delivery platforms, such as inorganic nanocarriers, demonstrate a high potential for cancer theranostic to overcome the cancer‐specific limitation of conventional low‐molecular‐weight anticancer agents and imaging probes. Specifically, it could achieve synergetic therapeutic effects, demonstrating stronger killing effects to MDR cancer cells by combining the inorganic nanocarriers with other treatment manners, such as RNA interference and thermal therapy. Moreover, the inorganic nanocarriers could provide imaging functions to help monitor treatment responses, e.g., drug resistance and therapeutic effects, as well as analyze the mechanism of MDR by molecular imaging modalities. In this review, the mechanisms involved in cancer MDR and recent advances of applying inorganic nanocarriers for MDR cancer imaging and therapy are summarized. The inorganic nanocarriers may circumvent cancer MDR for effective therapy and provide a way to track the therapeutic processes for real‐time molecular imaging, demonstrating high performance in studying the interaction of nanocarriers and MDR cancer cells/tissues in laboratory study and further shedding light on elaborate design of nanocarriers that could overcome MDR for clinical translation. PMID:27980988

  8. Resin glycosides from Ipomoea wolcottiana as modulators of the multidrug resistance phenotype in vitro.

    PubMed

    Corona-Castañeda, Berenice; Rosas-Ramírez, Daniel; Castañeda-Gómez, Jhon; Aparicio-Cuevas, Manuel Alejandro; Fragoso-Serrano, Mabel; Figueroa-González, Gabriela; Pereda-Miranda, Rogelio

    2016-03-01

    Recycling liquid chromatography was used for the isolation and purification of resin glycosides from the CHCl3-soluble extracts prepared using flowers of Ipomoea wolcottiana Rose var. wolcottiana. Bioassay-guided fractionation, using modulation of both antibiotic activity against multidrug-resistant strains of Gram-negative bacteria and vinblastine susceptibility in breast carcinoma cells, was used to isolate the active glycolipids as modulators of the multidrug resistance phenotype. An ester-type dimer, wolcottine I, one tetra- and three pentasaccharides, wolcottinosides I-IV, in addition to the known intrapilosin VII, were characterized by NMR spectroscopy and mass spectrometry. In vitro assays established that none of these metabolites displayed antibacterial activity (MIC>512 μg/mL) against multidrug-resistant strains of Escherichia coli, and two nosocomial pathogens: Salmonella enterica serovar Typhi and Shigella flexneri; however, when tested (25 μg/mL) in combination with tetracycline, kanamycin or chloramphenicol, they exerted a potentiation effect of the antibiotic susceptibility up to eightfold (64 μg/mL from 512 μg/mL). It was also determined that these non-cytotoxic (CI50>8.68 μM) agents modulated vinblastine susceptibility at 25 μg/mL in MFC-7/Vin(+) cells with a reversal factor (RFMCF-7/Vin(+)) of 2-130 fold.

  9. Inhibition of multidrug resistant Listeria monocytogenes by peptides isolated from combinatorial phage display libraries.

    PubMed

    Flachbartova, Z; Pulzova, L; Bencurova, E; Potocnakova, L; Comor, L; Bednarikova, Z; Bhide, M

    2016-01-01

    The aim of the study was to isolate and characterize novel antimicrobial peptides from peptide phage library with antimicrobial activity against multidrug resistant Listeria monocytogenes. Combinatorial phage-display library was used to affinity select peptides binding to the cell surface of multidrug resistant L. monocytogenes. After several rounds of affinity selection followed by sequencing, three peptides were revealed as the most promising candidates. Peptide L2 exhibited features common to antimicrobial peptides (AMPs), and was rich in Asp, His and Lys residues. Peptide L3 (NSWIQAPDTKSI), like peptide L2, inhibited bacterial growth in vitro, without any hemolytic or cytotoxic effects on eukaryotic cells. L1 peptide showed no inhibitory effect on Listeria. Structurally, peptides L2 and L3 formed random coils composed of α-helix and β-sheet units. Peptides L2 and L3 exhibited antimicrobial activity against multidrug resistant isolates of L. monocytogenes with no haemolytic or toxic effects. Both peptides identified in this study have the potential to be beneficial in human and veterinary medicine.

  10. Multidrug resistance proteins: role of P-glycoprotein, MRP1, MRP2, and BCRP (ABCG2) in tissue defense

    SciTech Connect

    Leslie, Elaine M.; Deeley, Roger G.; Cole, Susan P.C. . E-mail: coles@post.queensu.ca

    2005-05-01

    In tumor cell lines, multidrug resistance is often associated with an ATP-dependent decrease in cellular drug accumulation which is attributed to the overexpression of certain ATP-binding cassette (ABC) transporter proteins. ABC proteins that confer drug resistance include (but are not limited to) P-glycoprotein (gene symbol ABCB1), the multidrug resistance protein 1 (MRP1, gene symbol ABCC1), MRP2 (gene symbol ABCC2), and the breast cancer resistance protein (BCRP, gene symbol ABCG2). In addition to their role in drug resistance, there is substantial evidence that these efflux pumps have overlapping functions in tissue defense. Collectively, these proteins are capable of transporting a vast and chemically diverse array of toxicants including bulky lipophilic cationic, anionic, and neutrally charged drugs and toxins as well as conjugated organic anions that encompass dietary and environmental carcinogens, pesticides, metals, metalloids, and lipid peroxidation products. P-glycoprotein, MRP1, MRP2, and BCRP/ABCG2 are expressed in tissues important for absorption (e.g., lung and gut) and metabolism and elimination (liver and kidney). In addition, these transporters have an important role in maintaining the barrier function of sanctuary site tissues (e.g., blood-brain barrier, blood-cerebral spinal fluid barrier, blood-testis barrier and the maternal-fetal barrier or placenta). Thus, these ABC transporters are increasingly recognized for their ability to modulate the absorption, distribution, metabolism, excretion, and toxicity of xenobiotics. In this review, the role of these four ABC transporter proteins in protecting tissues from a variety of toxicants is discussed. Species variations in substrate specificity and tissue distribution of these transporters are also addressed since these properties have implications for in vivo models of toxicity used for drug discovery and development.

  11. Demonstrating a Multi-drug Resistant Mycobacterium tuberculosis Amplification Microarray

    PubMed Central

    Linger, Yvonne; Kukhtin, Alexander; Golova, Julia; Perov, Alexander; Qu, Peter; Knickerbocker, Christopher; Cooney, Christopher G.; Chandler, Darrell P.

    2014-01-01

    Simplifying microarray workflow is a necessary first step for creating MDR-TB microarray-based diagnostics that can be routinely used in lower-resource environments. An amplification microarray combines asymmetric PCR amplification, target size selection, target labeling, and microarray hybridization within a single solution and into a single microfluidic chamber. A batch processing method is demonstrated with a 9-plex asymmetric master mix and low-density gel element microarray for genotyping multi-drug resistant Mycobacterium tuberculosis (MDR-TB). The protocol described here can be completed in 6 hr and provide correct genotyping with at least 1,000 cell equivalents of genomic DNA. Incorporating on-chip wash steps is feasible, which will result in an entirely closed amplicon method and system. The extent of multiplexing with an amplification microarray is ultimately constrained by the number of primer pairs that can be combined into a single master mix and still achieve desired sensitivity and specificity performance metrics, rather than the number of probes that are immobilized on the array. Likewise, the total analysis time can be shortened or lengthened depending on the specific intended use, research question, and desired limits of detection. Nevertheless, the general approach significantly streamlines microarray workflow for the end user by reducing the number of manually intensive and time-consuming processing steps, and provides a simplified biochemical and microfluidic path for translating microarray-based diagnostics into routine clinical practice. PMID:24796567

  12. Demonstrating a multi-drug resistant Mycobacterium tuberculosis amplification microarray.

    PubMed

    Linger, Yvonne; Kukhtin, Alexander; Golova, Julia; Perov, Alexander; Qu, Peter; Knickerbocker, Christopher; Cooney, Christopher G; Chandler, Darrell P

    2014-04-25

    Simplifying microarray workflow is a necessary first step for creating MDR-TB microarray-based diagnostics that can be routinely used in lower-resource environments. An amplification microarray combines asymmetric PCR amplification, target size selection, target labeling, and microarray hybridization within a single solution and into a single microfluidic chamber. A batch processing method is demonstrated with a 9-plex asymmetric master mix and low-density gel element microarray for genotyping multi-drug resistant Mycobacterium tuberculosis (MDR-TB). The protocol described here can be completed in 6 hr and provide correct genotyping with at least 1,000 cell equivalents of genomic DNA. Incorporating on-chip wash steps is feasible, which will result in an entirely closed amplicon method and system. The extent of multiplexing with an amplification microarray is ultimately constrained by the number of primer pairs that can be combined into a single master mix and still achieve desired sensitivity and specificity performance metrics, rather than the number of probes that are immobilized on the array. Likewise, the total analysis time can be shortened or lengthened depending on the specific intended use, research question, and desired limits of detection. Nevertheless, the general approach significantly streamlines microarray workflow for the end user by reducing the number of manually intensive and time-consuming processing steps, and provides a simplified biochemical and microfluidic path for translating microarray-based diagnostics into routine clinical practice.

  13. Marine Natural Products as Models to Circumvent Multidrug Resistance.

    PubMed

    Long, Solida; Sousa, Emília; Kijjoa, Anake; Pinto, Madalena M M

    2016-07-08

    Multidrug resistance (MDR) to anticancer drugs is a serious health problem that in many cases leads to cancer treatment failure. The ATP binding cassette (ABC) transporter P-glycoprotein (P-gp), which leads to premature efflux of drugs from cancer cells, is often responsible for MDR. On the other hand, a strategy to search for modulators from natural products to overcome MDR had been in place during the last decades. However, Nature limits the amount of some natural products, which has led to the development of synthetic strategies to increase their availability. This review summarizes the research findings on marine natural products and derivatives, mainly alkaloids, polyoxygenated sterols, polyketides, terpenoids, diketopiperazines, and peptides, with P-gp inhibitory activity highlighting the established structure-activity relationships. The synthetic pathways for the total synthesis of the most promising members and analogs are also presented. It is expected that the data gathered during the last decades concerning their synthesis and MDR-inhibiting activities will help medicinal chemists develop potential drug candidates using marine natural products as models which can deliver new ABC transporter inhibitor scaffolds.

  14. Reversal of P-glycoprotein-mediated multidrug resistance by CD44 antibody-targeted nanocomplexes for short hairpin RNA-encoding plasmid DNA delivery.

    PubMed

    Gu, Jijin; Fang, Xiaoling; Hao, Junguo; Sha, Xianyi

    2015-03-01

    Multidrug resistance (MDR) remains one of the major reasons for the reductions in efficacy of many chemotherapeutic agents in cancer therapy. As a classical MDR phenotype of human malignancies, the adenosine triphosphate binding cassette (ABC)-transporter P-glycoprotein (MDR1/P-gp) is an efflux protein with aberrant activity that has been linked to multidrug resistance in cancer. For the reversal of MDR by RNA interference (RNAi) technology, an U6-RNA gene promoter-driven expression vector encoding anti-MDR1/P-gp short hairpin RNA (shRNA) molecules was constructed (abbreviated pDNA-iMDR1-shRNA). This study explored the feasibility of using Pluronic P123-conjugated polypropylenimine (PPI) dendrimer (P123-PPI) as a carrier for pDNA-iMDR1-shRNA to overcome tumor drug resistance in breast cancer cells. P123-PPI functionalized with anti-CD44 monoclonal antibody (CD44 receptor targeting ligand) (anti-CD44-P123-PPI) can efficiently condense pDNA into nanocomplexes to achieve efficient delivery of pDNA, tumor specificity and long circulation. The in vitro studies methodically evaluated the effect of P123-PPI and anti-CD44-P123-PPI on pDNA-iMDR1-shRNA delivery and P-gp downregulation. Our in vitro results indicated that the P123-PPI/pDNA and anti-CD44-P123-PPI/pDNA nanocomplexes with low cytotoxicity revealed higher transfection efficiency compared with the PPI/pDNA nanocomplexes and Lipofectamine™ 2000 in the presence of serum. The nanocomplexes loaded with pDNA-iMDR1-shRNA against P-gp could reverse MDR accompanied by the suppression of MDR1/P-gp expression at the mRNA and protein levels and improve the internalization and cytotoxicity of Adriamycin (ADR) in the MCF-7/ADR multidrug-resistant cell line. BALB/c nude mice bearing MCF-7/ADR tumor were utilized as a xenograft model to assess antitumor efficacy in vivo. The results demonstrated that the administration of anti-CD44-P123-PPI/pDNA-iMDR1-shRNA nanocomplexes combined with ADR could inhibit tumor growth more

  15. Bedaquiline: a novel antitubercular drug for multidrug-resistant tuberculosis.

    PubMed

    Nagabushan, H; Roopadevi, H S

    2014-01-01

    Multidrug-resistant and extensively drug-resistant tuberculosis (TB) are emerging global health threats. Bedaquiline is a new antituberculous drug belonging to the diarylquinoline class that efficiently inhibits the adenosine triphosphate synthase enzyme of Mycobacterium tuberculosis. It is a bactericidal and long-acting drug. It inhibits both dormant as well as replicating bacterial sub-populations and thus shortens the duration of TB treatment. This drug has been approved by the Food and Drug Administration in December 2012 for the management of multidrug resistant-TB. The drug marks the introduction of a new addition to the TB armamentarium after four decades.

  16. Multidrug resistant tuberculosis diagnosed by synovial fluid analysis.

    PubMed

    van Zeller, M; Monteiro, R; Ramalho, J; Almeida, I; Duarte, R

    2012-01-01

    Tuberculosis remains a major public health problem worldwide. HIV co-infection is contributing to an increased incidence of the disease, particularly that caused by multidrug resistant strains of Mycobacterium tuberculosis (MT). We describe an HIV-infected patient with pleural and lymph node tuberculosis diagnosed by pleural effusion characteristics and biopsy specimens, without MT identification, that further presented with knee-joint involvement. Arthrocentesis allowed MT isolation and drug susceptibility testing, resulting in a diagnosis of multidrug-resistant tuberculosis and an appropriate treatment regimen. MT identification and drug susceptibility tests are very important, especially for HIV co-infected patients.

  17. Geniposide reverses multidrug resistance in vitro and in vivo by inhibiting the efflux function and expression of P-glycoprotein

    PubMed Central

    Huang, Hefei; Zhang, Xuenong; Huang, Zhixiong; Zhang, Ye; Zhou, Zhiyong

    2017-01-01

    Geniposide is a water-soluble iridoid glucoside with anti-oxidant and anti-inflammatory biological functions. It has been indicated that geniposide may increase doxorubicin (DOX) accumulation in drug-resistant tumor cells. The present study aimed to investigate the resistance-reversing effect of geniposide in DOX-resistant cells and assess the underlying mechanisms of its action. The results revealed that geniposide itself weakly inhibited tumor cell growth. Furthermore, geniposide effectively reversed DOX resistance in a dose-dependent manner in human osteosarcoma DOX-resistant (MG63/DOX) cells. The action of geniposide was confirmed by increased accumulation of intracellular DOX detected in MG63/DOX cells. Notably, geniposide enhanced the efficacy of DOX against MG63/DOX cancer cell-derived xenografts in nude mice. To study the mechanism, intracellular accumulation of rhodamine 123 was measured using flow cytometry. At concentrations that reversed multidrug resistance (MDR), geniposide significantly downregulated P-glycoprotein (P-gp) expression. Therefore, geniposide reverses P-gp-mediated MDR by reducing the expression of P-gp and its transport function. The present study therefore indicated that geniposide may be administered in combination with conventional anti-neoplastic drugs to prevent MDR. PMID:28352312

  18. Thiazole-valine peptidomimetic (TTT-28) antagonizes multidrug resistance in vitro and in vivo by selectively inhibiting the efflux activity of ABCB1

    PubMed Central

    Wang, Yi-Jun; Patel, Bhargav A.; Anreddy, Nagaraju; Zhang, Yun-Kai; Zhang, Guan-Nan; Alqahtani, Saeed; Singh, Satyakam; Shukla, Suneet; Kaddoumi, Amal; Ambudkar, Suresh V.; Talele, Tanaji T.; Chen, Zhe-Sheng

    2017-01-01

    Multidrug resistance (MDR) attenuates the chemotherapy efficacy and increases the probability of cancer recurrence. The accelerated drug efflux mediated by ATP-binding cassette (ABC) transporters is one of the major MDR mechanisms. This study investigated if TTT-28, a newly synthesized thiazole-valine peptidomimetic, could reverse ABCB1-mediated MDR in vitro and in vivo. TTT-28 reversed the ABCB1-mediated MDR and increased the accumulation of [3H]-paclitaxel in ABCB1 overexpressing cells by selectively blocking the efflux function of ABCB1, but not interfering with the expression level and localization of ABCB1. Animal study revealed that TTT-28 enhanced the intratumoral concentration of paclitaxel and promoted apoptosis, thereby potently inhibiting the growth of ABCB1 overexpressing tumors. But TTT-28 did not induce the toxicity (cardiotoxicity/myelosuppression) of paclitaxel in mice. In this study, we synthesized and evaluated a novel selective inhibitor of ABCB1 (TTT-28) with high efficacy and low toxicity. The identification and characterization of this new thiazole-valine peptidomimetic will facilitate design and synthesis of a new generation of ABCB1 inhibitors, leading to further research on multidrug resistance and combination chemotherapy. Furthermore, the strategy that co-administer MDR-ABCB1 inhibitor to overcome the resistance of one FDA approved, widely used chemotherapeutic paclitaxel, may be promising direction for the field of adjuvant chemotherapy. PMID:28181548

  19. Nanomicelles loaded with doxorubicin and curcumin for alleviating multidrug resistance in lung cancer

    PubMed Central

    Gu, Yue; Li, Jing; Li, Yang; Song, Lei; Li, Dan; Peng, Liping; Wan, Ying; Hua, Shucheng

    2016-01-01

    Purpose A new type of polymeric micelle (PM) was assembled using a polyethylene glycol (PEG)-linked (PEGylated) amphiphilic copolymer and d-tocopheryl PEG1000 succinate (TPGS1000). The micelles were used to deliver doxorubicin (DOX) and curcumin (CUR) for alleviating multidrug resistance (MDR) in lung cancer cells while enhancing the therapeutic efficacy of DOX. Methods Micelles loaded with DOX and CUR were assembled using a film-forming technique. Micelles were used to treat A549/Adr cells to find out whether micelles had the ability to reverse the MDR of A549/Adr cells. Some investigations were conducted using tumor-bearing mice to assess whether these micelles had enhanced antitumor efficacy as compared to DOX alone or the combination of DOX and CUR. Results Some micelles (DOX + CUR)–PMs had a small average size of about 17 nm and showed definite ability to deliver both DOX and CUR into DOX-resistant A549/Adr cells. The PMs had high cytotoxicity toward A549/Adr cells when the applied equivalent DOX dose was 1 µg/mL or higher. The cellular uptake of (DOX + CUR)–PMs into A549/Adr cells was found to be associated with an energy-dependent, caveolae-mediated, and clathrin-independent mechanism. (DOX + CUR)–PMs helped to prolong the circulation of DOX or CUR as compared to the individual administration of DOX or CUR, and they exhibited high inhibiting efficiency against the growth of tumors and were able to reduce the side effects of DOX. Conclusion TPGS1000 and CUR could synergistically reverse DOX-resistance of A549/Adr cells. In vivo examinations confirmed that the micelles had the capability to increase the plasma concentration of DOX or CUR, as well as to prolong their respective blood circulation. These micelles were able to significantly inhibit tumor growth in Lewis lung carcinoma tumor-bearing mice while reducing the side effects of DOX. The micelles showed potential in the treatment of lung cancer. PMID:27843316

  20. OSI-930 analogues as novel reversal agents for ABCG2-mediated multidrug resistance.

    PubMed

    Kuang, Ye-Hong; Patel, Jay P; Sodani, Kamlesh; Wu, Chung-Pu; Liao, Li-Qiu; Patel, Atish; Tiwari, Amit K; Dai, Chun-Ling; Chen, Xiang; Fu, Li-Wu; Ambudkar, Suresh V; Korlipara, Vijaya L; Chen, Zhe-Sheng

    2012-09-15

    OSI-930, a dual c-Kit and KDR tyrosine kinase inhibitor, is reported to have undergone a Phase I dose escalation study in patients with advanced solid tumors. A series of fifteen pyridyl and phenyl analogues of OSI-930 were designed and synthesized. Extensive screening of these compounds led to the discovery that nitropyridyl and ortho-nitrophenyl analogues, VKJP1 and VKJP3, were effective in reversing ABC subfamily G member 2 (ABCG2) transporter-mediated multidrug resistance (MDR). VKJP1 and VKJP3 significantly sensitized ABCG2-expressing cells to established substrates of ABCG2 including mitoxantrone, SN-38, and doxorubicin in a concentration-dependent manner, but not to the non-ABCG2 substrate cisplatin. However, they were unable to reverse ABCB1- or ABCC1-mediated MDR indicating their selectivity for ABCG2. Western blotting analysis was performed to evaluate ABCG2 expression and it was found that neither VKJP1 nor VKJP3 significantly altered ABCG2 protein expression for up to 72 h. [(3)H]-mitoxantrone accumulation study demonstrated that VKJP1 and VKJP3 increased the intracellular accumulation of [(3)H]-mitoxantrone, a substrate of ABCG2. VKJP1 and VKJP3 also remarkably inhibited the transport of [(3)H]-methotrexate by ABCG2 membrane vesicles. Importantly, both VKJP1 and VKJP3 were efficacious in stimulating the activity of ATPase of ABCG2 and inhibited the photoaffinity labeling of this transporter by its substrate [(125)I]-iodoarylazidoprazosin. The results suggested that VKJP1 and VKJP3, specifically inhibit the function of ABCG2 through direct interaction with its substrate binding site(s). Thus VKJP1 and VKJP3 represent a new class of drugs for reducing MDR in ABCG2 over-expressing tumors.

  1. Epidemiology of Primary Multidrug-Resistant Tuberculosis, Vladimir Region, Russia.

    PubMed

    Ershova, Julia V; Volchenkov, Grigory V; Kaminski, Dorothy A; Somova, Tatiana R; Kuznetsova, Tatiana A; Kaunetis, Natalia V; Cegielski, J Peter; Kurbatova, Ekaterina V

    2015-11-01

    We studied the epidemiology of drug-resistant tuberculosis (TB) in Vladimir Region, Russia, in 2012. Most cases of multidrug-resistant TB (MDR TB) were caused by transmission of drug-resistant strains, and >33% were in patients referred for testing after mass radiographic screening. Early diagnosis of drug resistance is essential for preventing transmission of MDR TB.

  2. [Multi-drug resistant bacteria, a complex mechanism].

    PubMed

    Hilaire, Jean-Christophe

    2013-01-01

    Bacteria are said to be multidrug resistant when they are only sensitive to a small number of antibiotics used as treatments. This problem of resistance appeared in hospitals soon after antibiotics were first used. In the 1960s, strains of staphylococcus became resistant to penicillin.

  3. Multidrug-Resistant Staphylococcus aureus in US Meat and Poultry

    PubMed Central

    Waters, Andrew E.; Contente-Cuomo, Tania; Buchhagen, Jordan; Liu, Cindy M.; Watson, Lindsey; Pearce, Kimberly; Foster, Jeffrey T.; Bowers, Jolene; Driebe, Elizabeth M.; Engelthaler, David M.; Keim, Paul S.

    2011-01-01

    We characterized the prevalence, antibiotic susceptibility profiles, and genotypes of Staphylococcus aureus among US meat and poultry samples (n = 136). S. aureus contaminated 47% of samples, and multidrug resistance was common among isolates (52%). S. aureus genotypes and resistance profiles differed significantly among sample types, suggesting food animal–specific contamination. PMID:21498385

  4. Multidrug-Resistant Pathogens in Hospitalized Syrian Children

    PubMed Central

    Kassem, Diana Faour; Hoffmann, Yoav; Shahar, Naama; Ocampo, Smadar; Salomon, Liora; Zonis, Zeev

    2017-01-01

    Since 2013, wounded and ill children from Syria have received treatment in Israel. Screening cultures indicated that multidrug-resistant (MDR) pathogens colonized 89 (83%) of 107 children. For 58% of MDR infections, the pathogen was similar to that identified during screening. MDR screening of these children is valuable for purposes of isolation and treatment. PMID:27618479

  5. Invasive Infections with Multidrug-Resistant Yeast Candida auris, Colombia

    PubMed Central

    Morales-López, Soraya E.; Parra-Giraldo, Claudia M.; Ceballos-Garzón, Andrés; Martínez, Heidys P.; Rodríguez, Gerson J.; Álvarez-Moreno, Carlos A.

    2017-01-01

    Candida auris is an emerging multidrug-resistant fungus that causes a wide range of symptoms. We report finding 17 cases of C. auris infection that were originally misclassified but correctly identified 27.5 days later on average. Patients with a delayed diagnosis of C. auris had a 30-day mortality rate of 35.2%. PMID:27983941

  6. Multidrug-resistant tuberculosis, Somalia, 2010-2011.

    PubMed

    Sindani, Ireneaus; Fitzpatrick, Christopher; Falzon, Dennis; Suleiman, Bashir; Arube, Peter; Adam, Ismail; Baghdadi, Samiha; Bassili, Amal; Zignol, Matteo

    2013-03-01

    In a nationwide survey in 2011, multidrug-resistant tuberculosis (MDR TB) was found in 5.2% and 40.8% of patients with new and previously treated TB, respectively. These levels of drug resistance are among the highest ever documented in Africa and the Middle East. This finding presents a serious challenge for TB control in Somalia.

  7. Intravenous immunoglobulin enhances the killing activity and autophagy of neutrophils isolated from immunocompromised patients against multidrug-resistant bacteria.

    PubMed

    Matsuo, Hidemasa; Itoh, Hiroshi; Kitamura, Naoko; Kamikubo, Yasuhiko; Higuchi, Takeshi; Shiga, Shuichi; Ichiyama, Satoshi; Kondo, Tadakazu; Takaori-Kondo, Akifumi; Adachi, Souichi

    2015-08-14

    Intravenous immunoglobulin (IVIG) is periodically administered to immunocompromised patients together with antimicrobial agents. The evidence that supports the effectiveness of IVIG is mostly based on data from randomized clinical trials; the underlying mechanisms are poorly understood. A recent study revealed that killing of multidrug-resistant bacteria and drug-sensitive strains by neutrophils isolated from healthy donors is enhanced by an IVIG preparation. However, the effectiveness of IVIG in immunocompromised patients remains unclear. The present study found that IVIG increased both killing activity and O2(-) release by neutrophils isolated from six patients receiving immune-suppressive drugs after hematopoietic stem cell transplantation (HSCT); these neutrophils killed both multidrug-resistant extended-spectrum β-lactamase-producing Escherichia coli (E. coli) and multidrug-resistant Pseudomonas aeruginosa (P. aeruginosa). Moreover, IVIG increased the autophagy of the neutrophils, which is known to play an important role in innate immunity. These results suggest that IVIG promotes both the killing activity and autophagy of neutrophils isolated from immunocompromised patients against multidrug-resistant bacteria.

  8. Proteome analysis of multidrug-resistant, breast cancer–derived microparticles

    PubMed Central

    Pokharel, Deep; Padula, Matthew P.; Lu, Jamie F.; Tacchi, Jessica L.; Luk, Frederick; Djordjevic, Steven P.; Bebawy, Mary

    2014-01-01

    Cancer multidrug resistance (MDR) occurs when cancer cells evade the cytotoxic actions of chemotherapeutics through the active efflux of drugs from within the cells. Our group have previously demonstrated that multidrug-resistant breast cancer cells spontaneously shed microparticles (MPs) and that these MPs can transfer resistance to drug-responsive cells and confer MDR on those cells in as little as 4 h. Furthermore, we also showed that, unlike MPs derived from leukaemia cells, breast cancer–derived MPs display a tissue selectivity in the transfer of P-glycoprotein (P-gp), transferring the resistance protein only to malignant breast cells. This study aims to define the proteome of breast cancer–derived MPs in order to understand the differences in protein profiles between those shed from drug-resistant versus drug-sensitive breast cancer cells. In doing so, we detail the protein cargo required for the intercellular transfer of MDR to drug-sensitive recipient cells and the factors governing the transfer selectivity to malignant breast cells. We describe the first proteomic analysis of MPs derived from human breast cancer cells using SDS PAGE and liquid chromatography–tandem mass spectrometry (LC/MS/MS), in which we identify 120 unique proteins found only in drug-resistant, breast cancer–derived MPs. Our results demonstrate that the MP-mediated transfer of P-gp to recipient cells occurs alongside CD44; the Ezrin, Radixin and Moesin protein family (ERM); and cytoskeleton motor proteins within the MP cargo. PMID:25206959

  9. Amplification of the multidrug resistance gene pfmdr1 in Plasmodium falciparum has arisen as multiple independent events.

    PubMed

    Triglia, T; Foote, S J; Kemp, D J; Cowman, A F

    1991-10-01

    The multidrug resistance (MDR) phenotype in mammalian tumor cells can involve amplification of mdr genes that results in overexpression of the protein product termed P-glycoprotein. Chloroquine resistance (CQR) in Plasmodium falciparum has similarities with the MDR phenotype in tumor cells, and some isolates of P. falciparum have amplified levels of the pfmdr1 gene. To investigate the nature and origin of pfmdr1 amplicons, we have cloned large regions of a 110-kb amplicon from the CQR cloned isolate B8 by using the yeast artificial chromosome system. We have identified and sequenced the breakpoints of the amplicon by a novel method employing inverted polymerase chain reaction that is applicable to analysis of any large-scale repeat. We show that the five copies of the amplicon in this isolate are in a head to tail configuration. A string of 30 A's flank the breakpoints on each side of the amplified segment, suggesting a mechanism for the origin of the tandem amplification. Polymerase chain reaction analysis with oligonucleotides that cross the B8 breakpoint has shown in 26 independent CQR isolates, 16 of which contain amplified copies of pfmdr1, that amplification of the pfmdr1 gene in P. falciparum has arisen as multiple independent events. These results suggest that this region of the genome is under strong selective pressure.

  10. Formulation development of a novel targeted theranostic nanoemulsion of docetaxel to overcome multidrug resistance in ovarian cancer

    PubMed Central

    Ganta, Srinivas; Singh, Amit; Rawal, Yashesh; Cacaccio, Joseph; Patel, Niravkumar R.; Kulkarni, Praveen; Ferris, Craig F.; Amiji, Mansoor M.; Coleman, Timothy P.

    2015-01-01

    Objective Ovarian cancer is a highly lethal disease in which the majority of patients eventually demonstrate multidrug resistance. Develop a novel active targeted theranostic nanomedicine designed to overcome drug efflux mechanisms, using a Generally Regarded As Safe (GRAS) grade nanoemulsion (NE) as a clinically relevant platform. Materials and methods The NEs surface-functionalized with folate and gadolinium, were made using GRAS grade excipients and a high-shear microfluidization process. Efficacy was evaluated in ovarian cancer cells, SKOV3 and SKOV3TR. The NE accumulation in tumors was evaluated in SKOV3 tumor-bearing mice by magnetic resonance imaging (MRI). Results and discussion The NE with particle size <150nm were stable in plasma and parenteral fluids for 24 h. Ovarian cancer cells in vitro efficiently took up the non-targeted and folate-targeted NEs; improved cytotoxicity was observed for the folate-targeted NEs showing a 270- fold drop in the IC50 in SKOV3TR cells as compared to docetaxel alone. The addition of gadolinium did not affect cell viability in vitro, but showed relaxation times comparable to Magnevist®. Folate-targeted NEs accumulated in tumors for prolonged period of time compared to Magnevist® and showed enhanced contrast compared to non-targeted NEs with MRI in SKOV3 tumor-bearing mice suggesting active targeting of NEs due to folate modification. Conclusions A folate-targeted, theranostic NE delivers docetaxel by receptor mediated endocytosis that shows enhanced cytotoxicity capable of overcoming ABC transporter mediated taxane resistance. The diagnostic capability of the targeted nanomedicine showed enhanced contrast in tumors compared to clinically relevant MRI contrast agent Magnevist®. PMID:24901206

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

    PubMed

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

    2017-02-16

    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.

  12. Transferrin receptor-targeted pH-sensitive micellar system for diminution of drug resistance and targetable delivery in multidrug-resistant breast cancer

    PubMed Central

    Gao, Wei; Ye, Guihua; Duan, Xiaochuan; Yang, Xiaoying; Yang, Victor C

    2017-01-01

    The emergence of drug resistance is partially associated with overproduction of transferrin receptor (TfR). To overcome multidrug resistance (MDR) and achieve tumor target delivery, we designed a novel biodegradable pH-sensitive micellar system modified with HAIYPRH, a TfR ligand (7pep). First, the polymers poly(l-histidine)-coupled polyethylene glycol-2000 (PHIS-PEG2000) and 7pep-modified 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol-2000 (7pep-DSPE-PEG2000) were synthesized, and the mixed micelles were prepared by blending of PHIS-PEG2000 and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-polyethylene glycol-2000 (DSPE-PEG2000) or 7pep-DSPE-PEG2000 (7-pep HD micelles). The micelles exhibited good size uniformity, high encapsulation efficiency, and a low critical micelle concentration. By changing the polymer ratio in the micellar formulation, the pH response range was specially tailored to pH ~6.0. When loaded with antitumor drug doxorubicin (DOX), the micelle showed an acid pH-triggering drug release profile. The cellular uptake and cytotoxicity study demonstrated that 7-pep HD micelles could significantly enhance the intracellular level and antitumor efficacy of DOX in multidrug-resistant cells (MCF-7/Adr), which attributed to the synergistic effect of poly(l-histidine)-triggered endolysosom escape and TfR-mediated endocytosis. Most importantly, the in vivo imaging study confirmed the target-ability of 7-pep HD micelles to MDR tumor. These findings indicated that 7-pep HD micelles would be a promising drug delivery system in the treatment of drug-resistant tumors. PMID:28223798

  13. Multidrug-resistant tuberculosis in transplant recipients: Case report and review of the literature.

    PubMed

    Huaman, Moises A; Brawley, Robert; Ashkin, David

    2017-04-01

    Transplant recipients are at increased risk of tuberculosis (TB). We describe a case of pulmonary and vertebral multidrug-resistant TB (MDR-TB) in a kidney transplant patient who required neurosurgical intervention and unfortunately developed fatal nosocomial complications. Thirteen transplant recipients with MDR-TB were previously reported in the literature (one hematopoietic cell transplant, one heart transplant, one lung transplant, one heart-lung transplant, and nine kidney transplant recipients). Extrapulmonary disease, severe treatment complications, and deaths were observed in patients who developed MDR-TB after transplantation.

  14. Successful Treatment of Multiple Multidrug Resistant Intracranial Tuberculomata

    PubMed Central

    Goldberg, Hazel F.; Mellick, Ross S.; Post, Jeffrey J.

    2016-01-01

    A 21-year-old Bangladesh-born man presented with a month history of evolving neurological symptoms in the context of a six-month history of fever, night sweats, and axillary lymphadenopathy. He was subsequently diagnosed with multiple multidrug resistant intracranial tuberculomata and was successfully treated over two years. Intracranial multidrug resistant tuberculosis has a high mortality and successful treatment is rarely reported. Management is complex and requires consideration of the penetration and likely effect of antituberculous agents within the central nervous system. We discuss the role of various antituberculous agents, the duration of therapy, the utility of corticosteroids, the value of intrathecal and systemic therapy, and the need for rapid diagnosis. PMID:28127479

  15. Molecular fingerprinting of multidrug-resistant Salmonella enterica serotype Typhi.

    PubMed Central

    Hampton, M. D.; Ward, L. R.; Rowe, B.; Threlfall, E. J.

    1998-01-01

    For epidemiologic investigations, the primary subdivision of Salmonella Typhi is vi-phage typing; 106 Vi-phage types are defined. For multidrug-resistant strains the most common types have been M1 (Pakistan) and E1 (India, Pakistan, Bangladesh, and the Arabian Gulf); a strain untypable with the Vi phages has been responsible for a major epidemic in Tajikistan. Most often, isolates from the Indian subcontinent have been resistant to ampicillin, chloramphenicol, streptomycin, sulfonamides, tetracyclines, and trimethoprim; but in the 1997 Tajikistan outbreak, the epidemic strain was also resistant to ciprofloxacin. For multidrug-resistant strains, subdivision within phage type can be achieved by plasmid profile typing and pulsed-field gel electrophoresis. PMID:9621206

  16. Solid lipid nanoparticles with TPGS and Brij 78: A co-delivery vehicle of curcumin and piperine for reversing P-glycoprotein-mediated multidrug resistance in vitro

    PubMed Central

    Tang, Jingling; Ji, Hongyu; Ren, Jinmei; Li, Mengting; Zheng, Nannan; Wu, Linhua

    2017-01-01

    Multidrug resistance (MDR) is a main clinical hurdle for chemotherapy of cancer, and overexpression of P-glycoprotein (P-gp) is a key factor. In the present study, a new co-delivery system for reversing MDR was designed and developed. The system was composed of curcumin (Cur) and piperine (Pip) encapsulated in solid lipid nanoparticles (SLNs) with tocopheryl polyethylene glycol succinate (TPGS) and Brij 78 [(Cur+Pip)-SLNs]. TPGS and Brij 78 could sensitize MDR tumors by inhibiting the P-gp drug efflux system. The combination of Cur and Pip, when administered in SLNs formulations, resulted in a significant enhancement in cytotoxicity and allowed efficient intracellular delivery of the drugs in drug-resistant A2780/Taxol cells. This dual inhibitory strategy may have significant potential in the clinical management of MDR in cancer. PMID:28123572

  17. Multidrug Resistant Shigella flexneri Infection Simulating Intestinal Intussusception

    PubMed Central

    Sreenivasan, Srirangaraj; Kali, Arunava; Pradeep, Jothimani

    2016-01-01

    Shigella enteritis remains an important cause of mortality and morbidity in all age groups, in developing as well as developed countries. Owing to the emerging resistance to multiple antibiotics among Shigella spp., it has been recognized as a major global public health concern and warrants constant monitoring of its resistance pattern. We report a case of segmental ileitis caused by non.-ESBL producing multidrug resistant Shigella flexneri in an infant clinically mimicking intussusception, which was effectively treated by ceftriaxone. PMID:27013815

  18. Isolation of multidrug-resistant Salmonella in Singapore

    PubMed Central

    Phoon, Yee Wei; Chan, Yuen Yue Candice; Koh, Tze Hsien

    2015-01-01

    Multidrug-resistant Salmonella is a well-recognised problem worldwide, especially in developing countries such as India, where non-typhoidal Salmonella infections and enteric fever are endemic. Antimicrobial resistance, particularly to fluoroquinolones, is common and leads to the frequent use of alternative agents, such as azithromycin. We herein describe the first reported case of azithromycin-resistant Salmonella gastroenteritis in a Singaporean patient. PMID:26311915

  19. Tackling Threats and Future Problems of Multidrug-Resistant Bacteria.

    PubMed

    Medina, Eva; Pieper, Dietmar Helmut

    2016-01-01

    With the advent of the antibiotic era, the overuse and inappropriate consumption and application of antibiotics have driven the rapid emergence of multidrug-resistant pathogens. Antimicrobial resistance increases the morbidity, mortality, length of hospitalization and healthcare costs. Among Gram-positive bacteria, Staphylococcus aureus (MRSA) and multidrug-resistant (MDR) Mycobacterium tuberculosis, and among the Gram-negative bacteria, extended-spectrum beta-lactamase (ESBLs)-producing bacteria have become a major global healthcare problem in the 21st century. The pressure to use antibiotics guarantees that the spread and prevalence of these as well as of future emerging multidrug-resistant pathogens will be a persistent phenomenon. The unfeasibility of reversing antimicrobial resistance back towards susceptibility and the critical need to treat bacterial infection in modern medicine have burdened researchers and pharmaceutical companies to develop new antimicrobials effective against these difficult-to-treat multidrug-resistant pathogens. However, it can be anticipated that antibiotic resistance will continue to develop more rapidly than new agents to treat these infections become available and a better understanding of the molecular, evolutionary and ecological mechanisms governing the spread of antibiotic resistance is needed. The only way to curb the current crisis of antimicrobial resistance will be to develop entirely novel strategies to fight these pathogens such as combining antimicrobial drugs with other agents that counteract and obstruct the antibiotic resistant mechanisms expressed by the pathogen. Furthermore, as many antibiotics are often inappropriately prescribed, a more personalized approach based on precise diagnosis tools will ensure that proper treatments can be promptly applied leading to more targeted and effective therapies. However, in more general terms, also the overall use and release of antibiotics in the environment needs to be

  20. Imipenem: a potent inducer of multidrug resistance in Acinetobacter baumannii.

    PubMed

    Kuo, Han-Yueh; Chang, Kai-Chih; Kuo, Jai-Wei; Yueh, Hui-Wen; Liou, Ming-Li

    2012-01-01

    This study investigated the progression of multidrug resistance upon exposure to imipenem in Acinetobacter baumannii. Eighteen A. baumannii strains, including two reference strains (ATCC 19606 and ATCC 17978), four clinical strains (AB56, AB242, AB273 and AB279) and 12 antibiotic-selected mutant strains, were used in this study. Imipenem-selected mutants were generated from imipenem-susceptible strains (ATCC 19606, ATCC 17978 and AB242) by multistep selection resistance. Amikacin-, ciprofloxacin-, colistin-, meropenem- and ceftazidime-selected mutants were also generated from the two reference strains and were used for comparison. Antibiotic susceptibilities in the absence and presence of the efflux pump inhibitors carbonyl cyanide m-chlorophenylhydrazone (CCCP) and 1-(1-naphthylmethyl)-piperazine (NMP) were examined in the three imipenem-selected mutants and the three clinical multidrug-resistant (MDR) isolates. Expression profiles of the antimicrobial resistance genes in the imipenem-selected mutants and their parental strains were also determined. The results showed that imipenem was more likely, compared with the other antibiotics, to induce a MDR phenotype in the two reference strains. Differences in OXA-51-like carbapenemase, efflux pumps or/and AmpC β-lactamase expression were observed in the three imipenem-selected mutants. Moreover, a reduction in imipenem or amikacin resistance was observed when the imipenem-selected mutants and clinical isolates were exposed to NMP and CCCP. This study concluded that imipenem might be a potent inducer of multidrug resistance in A. baumannii strains. OXA-51-like carbapenemase combined with other resistance mechanisms may contribute to the development of multidrug resistance in A. baumannii. Monitoring the use of carbapenems is required to reduce the spread of MDR A. baumannii in hospitals.

  1. Multidrug Resistant Shigella flexneri Infection Simulating Intestinal Intussusception.

    PubMed

    Sreenivasan, Srirangaraj; Kali, Arunava; Pradeep, Jothimani

    2016-01-01

    Shigella enteritis remains an important cause of mortality and morbidity in all age groups, in developing as well as developed countries. Owing to the emerging resistance to multiple antibiotics among Shigella spp., it has been recognized as a major global public health concern and warrants constant monitoring of its resistance pattern. We report a case of segmental ileitis caused by non.-ESBL producing multidrug resistant Shigella flexneri in an infant clinically mimicking intussusception, which was effectively treated by ceftriaxone.

  2. Reversal of the multidrug resistance by drug combination using multifunctional liposomes

    NASA Astrophysics Data System (ADS)

    Patel, Niravkumar R.

    One of the major obstacles to the success of cancer chemotherapy is the multi-drug resistance (MDR) that results due mainly to the over-expression of drug efflux transporter pumps such as P-glycoprotein (P-gp). Highly efficacious third generation P-gp inhibitors, like tariquidar, have shown promising results against MDR. However, P-gp is also expressed in normal tissues like the blood-brain barrier, gastrointestinal tract, liver and kidney. It is therefore important to limit the exposure of P-gp inhibitors to normal tissues and increase their co-localization with anticancer agents in tumor tissues to maximize the efficacy of a P-gp inhibitor. To minimize non-specific binding and increase its delivery to tumor tissues, liposomes, self-assembling phospholipid vesicles, were chosen as a drug delivery vehicle. The liposome has been identified as a system capable of carrying molecules with diverse physicochemical properties. It can also alter the pharmacokinetic profile of loaded molecules which is a concern with both tariquidar and paclitaxel. Liposomes can easily be surface-modified rendering them cell-specific as well as organelle-specific. The main objective of present study was to develop an efficient liposomal delivery system which would deliver therapeutic molecules of interest to tumor tissues and avoid interaction with normal tissues. In this study, the co-delivery of tariquidar and paclitaxel into tumor cells to reverse the MDR using long-circulating cationic liposomes was investigated. SKOV-3TR, the resistant variant of SKOV-3 and MCF-7/ADR, the resistant variant of MCF-7 were used as model cell lines. Uniform liposomal formulations were generated with high incorporation efficiency and no apparent decrease in tariquidar potency towards P-gp. Tariquidar- and paclitaxel- co-loaded long-circulating liposomes showed significant re-sensitization of SKOV-3TR and MCF-7/ADR for paclitaxel in vitro. Further modification of these liposomes with antitumor 2C5 resulted

  3. Intravesical colistin irrigation to treat multidrug-resistant Acinetobacter baumannii urinary tract infection: a case report

    PubMed Central

    2012-01-01

    Introduction Acinetobacter baumannii is a Gram-negative bacteria and a significant nosocomial pathogen in hospitals. Multidrug-resistant A. baumannii have emerged as a cause of nosocomial infections in critically ill patients. This microorganism has the ability to produce biofilms on different surfaces, which could explain their ability to persist in clinical environments and their role in device-related infections. Case presentation We present the case of a 33-year-old Hispanic man with local invasive retroperitoneal leiomyosarcoma and right kidney exclusion along with femoral venous thrombosis, who was admitted for tumor resection. He had been receiving multiple nephrotoxic antibiotics for a long time (including tigecycline and colistimethate sodium) and had a persistent urinary infection related to multidrug-resistant A. baumannii (with susceptibility to colistimethate). Colistimethate was administered through a three-lumen urinary device for continuous urinary irrigation over seven days. Our patient did not refer to any adverse effects. A urine culture control taken at the end of the irrigation and another taken 10 days later were negative. Conclusion Colistimethate sodium and other antimicrobials infused by urinary irrigation can be a good option in patients in whom parenteral administration could be toxic. PMID:23273314

  4. Expression, detergent solubilization, and purification of a membrane transporter, the MexB multidrug resistance protein.

    PubMed

    Bhatt, Forum H; Jeffery, Constance J

    2010-12-03

    Multidrug resistance (MDR), the ability of a cancer cell or pathogen to be resistant to a wide range of structurally and functionally unrelated anti-cancer drugs or antibiotics, is a current serious problem in public health. This multidrug resistance is largely due to energy-dependent drug efflux pumps. The pumps expel anti-cancer drugs or antibiotics into the external medium, lowering their intracellular concentration below a toxic threshold. We are studying multidrug resistance in Pseudomonas aeruginosa, an opportunistic bacterial pathogen that causes infections in patients with many types of injuries or illness, for example, burns or cystic fibrosis, and also in immuno-compromised cancer, dialysis, and transplantation patients. The major MDR efflux pumps in P. aeruginosa are tripartite complexes comprised of an inner membrane proton-drug antiporter (RND), an outer membrane channel (OMF), and a periplasmic linker protein (MFP). The RND and OMF proteins are transmembrane proteins. Transmembrane proteins make up more than 30% of all proteins and are 65% of current drug targets. The hydrophobic transmembrane domains make the proteins insoluble in aqueous buffer. Before a transmembrane protein can be purified, it is necessary to find buffer conditions containing a mild detergent that enable the protein to be solubilized as a protein detergent complex (PDC). In this example, we use an RND protein, the P. aeruginosa MexB transmembrane transporter, to demonstrate how to express a recombinant form of a transmembrane protein, solubilize it using detergents, and then purify the protein detergent complexes. This general method can be applied to the expression, purification, and solubilization of many other recombinantly expressed membrane proteins. The protein detergent complexes can later be used for biochemical or biophysical characterization including X-ray crystal structure determination or crosslinking studies.

  5. Characterization of site-specific glycosylation of secreted proteins associated with multi-drug resistance of gastric cancer

    PubMed Central

    Li, Ting; Cheng, Kai; Dong, Jiaqiang; Tian, Miaomiao; Chai, Na; Guo, Hao; Li, Jinjing; You, Xin; Dong, Mingming; Ye, Mingliang; Nie, Yongzhan; Zou, Hanfa; Fan, Daiming

    2016-01-01

    Multi-drug resistance (MDR) remains a great obstacle to effective chemotherapy for gastric cancer. A number of secreted glycoproteins have been reported to be involved in the development of MDR in gastric cancer. However, whether glycosylation of secreted glycoproteins changes during MDR of gastric cancer is unclear. Our present work manifested that N-glycosites and site-specific glycoforms of secreted proteins in drug-resistant cell lines were distinctly different from those in the parental cell line for the first time. Further characterization highlighted the significance of some aberrantly glycosylated secretory proteins in MDR, suggesting that manipulating the glycosylation of specific glycoproteins could be a potential target for overcoming multi-drug resistance in gastric cancer. PMID:27015365

  6. A multidrug resistance plasmid contains the molecular switch for type VI secretion in Acinetobacter baumannii

    PubMed Central

    Weber, Brent S.; Ly, Pek Man; Irwin, Joshua N.; Pukatzki, Stefan; Feldman, Mario F.

    2015-01-01

    Infections with Acinetobacter baumannii, one of the most troublesome and least studied multidrug-resistant superbugs, are increasing at alarming rates. A. baumannii encodes a type VI secretion system (T6SS), an antibacterial apparatus of Gram-negative bacteria used to kill competitors. Expression of the T6SS varies among different strains of A. baumannii, for which the regulatory mechanisms are unknown. Here, we show that several multidrug-resistant strains of A. baumannii harbor a large, self-transmissible resistance plasmid that carries the negative regulators for T6SS. T6SS activity is silenced in plasmid-containing, antibiotic-resistant cells, while part of the population undergoes frequent plasmid loss and activation of the T6SS. This activation results in T6SS-mediated killing of competing bacteria but renders A. baumannii susceptible to antibiotics. Our data show that a plasmid that has evolved to harbor antibiotic resistance genes plays a role in the differentiation of cells specialized in the elimination of competing bacteria. PMID:26170289

  7. Thanatin activity on multidrug resistant clinical isolates of Enterobacter aerogenes and Klebsiella pneumoniae.

    PubMed

    Pagès, Jean-Marie; Dimarcq, Jean-Luc; Quenin, Solange; Hetru, Charles

    2003-09-01

    Efflux pumps protect bacterial cells by ejecting intracellular toxic molecules such as antibiotics, detergents and defensins that have penetrated the cell envelope. Some of these efflux pumps recognise structurally unrelated compounds (mdr pump) and account for the resistance of some organisms to two or more agents. It would be of interest to identify molecules that are able to circumvent the problems created by multidrug resistance phenotypes during antibiotic therapy. We have studied the activity of thanatin, a 21-residue cationic antimicrobial peptide produced by an insect, against three bacterial species. The antibacterial effect depended on the size of lipopolysaccharide side chains. In clinically resistant isolates of Enterobacter aerogenes and Klebsiella pneumoniae, the biological activity of thanatin is independent of the membrane permeability, possibly controlled by one or more porins, and/or the expression of drug efflux pumps, two mechanisms which confer high level antibiotic resistance. In addition, thanatin was able to improve the activity of structurally unrelated antibiotics (norfloxacin, chloramphenicol, tetracycline) on a multidrug- resistant E. aerogenes clinical isolate.

  8. Toxicological relevance of the multidrug resistance protein 1, MRP1 (ABCC1) and related transporters.

    PubMed

    Leslie, E M; Deeley, R G; Cole, S P

    2001-10-05

    The 190 kDa multidrug resistance protein 1 (MRP1/ABCC1) is a founding member of a subfamily of the ATP binding cassette (ABC) superfamily of transport proteins and was originally identified on the basis of its elevated expression in multidrug resistant lung cancer cells. In addition to its ability to confer resistance in tumour cells, MRP1 is ubiquitously expressed in normal tissues and is a primary active transporter of GSH, glucuronate and sulfate conjugated and unconjugated organic anions of toxicological relevance. Substrates include lipid peroxidation products, herbicides, tobacco specific nitrosamines, mycotoxins, heavy metals, and natural product and antifolate anti-cancer agents. MRP1 also transports unmodified xenobiotics but often requires GSH to do so. Active efflux is generally an important aspect of cellular detoxification since it prevents the accumulation of conjugated and unconjugated compounds that have the potential to be directly toxic. The related transporters MRP2 and MRP3 have overlapping substrate specificities with MRP1 but different tissue distributions, and evidence that they also have chemoprotective functions are discussed. Finally, MRP homologues have been described in other species including yeast and nematodes. Those isolated from the vascular plant Arabidopsis thaliana (AtMRPs) decrease the cytoplasmic concentration of conjugated toxins through sequestration in vacuoles and are implicated in providing herbicide resistance to plants.

  9. Interferon-Gamma Improves Macrophages Function against M. tuberculosis in Multidrug-Resistant Tuberculosis Patients

    PubMed Central

    Mazhar, Humaira; Muhammad, Niaz; Abbas, Muhammad Nasser

    2016-01-01

    Background. Mycobacterium tuberculosis (M. tuberculosis) that causes tuberculosis (TB) kills millions of infected people annually especially multidrug-resistant tuberculosis (MDR-TB). On infection, macrophages recognize the mycobacteria by toll-like receptor (TLR) followed by phagocytosis and control of mycobacteria. In addition, macrophages also secrete IL-12 to induce IFN-γ production by T, which, in turn, increases the phagocytosis and oxidative burst. Individuals with defects in innate or adaptive immunity exhibit increased susceptibility to M. tuberculosis. Understanding these immunologic mechanisms will help in TB control. We aimed to investigate the immunopathologic mechanisms in MDR-TB and role of recombinant human interferon-gamma (rhIFN-γ). Study Design and Methods. Monocyte-derived macrophages (MDMs) were generated from peripheral blood mononuclear cells of MDR-TB patients and healthy subjects and were investigated for immunologic response by ELISA and flow cytometry. Results. Different functional and molecular anomalies were observed in macrophages. In addition, a defective immune response to M. tuberculosis from the patient's MDMs was characterized, which in turn improved by pretreatment with rhIFN-γ. Conclusion. This work highlights the fact that rhIFN-γ improves macrophages function against M. tuberculosis and treatment of patients with poor responsiveness to TB therapy may be needed in future to include IFN-γ as adjuvant therapy after the full characterization of pathological and molecular mechanisms in these and in other more multidrug-resistant TB patients. PMID:27478636

  10. Characterization of putative multidrug resistance transporters of the major facilitator-superfamily expressed in Salmonella Typhi.

    PubMed

    Shaheen, Aqsa; Ismat, Fouzia; Iqbal, Mazhar; Haque, Abdul; De Zorzi, Rita; Mirza, Osman; Walz, Thomas; Rahman, Moazur

    2015-05-01

    Multidrug resistance mediated by efflux pumps is a well-known phenomenon in infectious bacteria. Although much work has been carried out to characterize multidrug efflux pumps in Gram-negative and Gram-positive bacteria, such information is still lacking for many deadly pathogens. The aim of this study was to gain insight into the substrate specificity of previously uncharacterized transporters of Salmonella Typhi to identify their role in the development of multidrug resistance. S. Typhi genes encoding putative members of the major facilitator superfamily were cloned and expressed in the drug-hypersensitive Escherichia coli strain KAM42, and tested for transport of 25 antibacterial compounds, including representative antibiotics of various classes, antiseptics, dyes and detergents. Of the 15 tested putative transporters, STY0901, STY2458 and STY4874 exhibited a drug-resistance phenotype. Among these, STY4874 conferred resistance to at least ten of the tested antimicrobials: ciprofloxacin, norfloxacin, levofloxacin, kanamycin, streptomycin, gentamycin, nalidixic acid, chloramphenicol, ethidium bromide, and acriflavine, including fluoroquinolone antibiotics, which were drugs of choice to treat S. Typhi infections. Cell-based functional studies using ethidium bromide and acriflavine showed that STY4874 functions as a H(+)-dependent exporter. These results suggest that STY4874 may be an important drug target, which can now be tested by studying the susceptibility of a STY4874-deficient S. Typhi strain to antimicrobials.

  11. Discovering Natural Product Modulators to Overcome Multidrug Resistance in Cancer Chemotherapy

    PubMed Central

    Wu, Chung-Pu; Ohnuma, Shinobu; Ambudkar, Suresh V.

    2012-01-01

    Multidrug resistance caused by the overexpression of ABC drug transporters is a major obstacle in clinical cancer chemotherapy. For several years, it appeared that direct inhibition of ABC transporters would be the cheapest and most efficient way to combat this problem. Unfortunately, progress in finding a potent, selective inhibitor to modulate ABC transporters and restore drug sensitivity in multidrug-resistant cancer cells has been slow and challenging. Candidate drugs should ideally be selective, potent and relatively non-toxic. Many researchers in recent years have turned their attention to utilizing natural products as the building blocks for the development of the next generation of inhibitors, especially after the disappointing results obtained from inhibitors of the first three generations at the clinical trial stage. The first step is to discover natural substances (distinct from the first three generation inhibitors) that are potent, selective and relatively non-toxic in order to be used clinically. Here, we present a brief overview of the prospect of using natural products to modulate the function of ABC drug transporters clinically and their impact on human physiology and pharmacology. PMID:21118092

  12. A Potato cDNA Encoding a Homologue of Mammalian Multidrug Resistant P-Glycoprotein

    NASA Technical Reports Server (NTRS)

    Wang, W.; Takezawa, D.; Poovaiah, B. W.

    1996-01-01

    A homologue of the multidrug resistance (MDR) gene was obtained while screening a potato stolon tip cDNA expression library with S-15-labeled calmodulin. The mammalian MDR gene codes for a membrane-bound P-glycoprotein (170-180 kDa) which imparts multidrug resistance to cancerous cells. The potato cDNA (PMDR1) codes for a polypeptide of 1313 amino acid residues (ca. 144 kDa) and its structural features are very similar to the MDR P-glycoprotein. The N-terminal half of the PMDR1-encoded protein shares striking homology with its C-terminal half, and each half contains a conserved ATP-binding site and six putative transmembrane domains. Southern blot analysis indicated that potato has one or two MDR-like genes. PMDR1 mRNA is constitutively expressed in all organs studied with higher expression in the stem and stolon tip. The PMDR1 expression was highest during tuber initiation and decreased during tuber development.

  13. Presence of Multidrug Resistant Enteric Bacteria in Dairy Farm Topsoil

    PubMed Central

    Burgos, J. M.; Ellington, B. A.; Varela, M. F.

    2008-01-01

    In addition to human and veterinary medicine, antibiotics are extensively used in agricultural settings, such as for treatment of infections, growth enhancement and prophylaxis in food animals, leading to selection of drug and multidrug resistant bacteria. In order to help circumvent the problem of bacterial antibiotic resistance, it is first necessary to understand the scope of the problem. However, is it not fully understood how widespread antibiotic resistant bacteria are in agricultural settings. The lack of such surveillance data is especially evident in dairy farm environments, such as soil. It is also unknown to what extent various physiological modulators, such as salycilate, a component of aspirin and known model modulator of multiple antibiotic resistance (mar) genes, influence bacterial multidrug resistance. We isolated and identified enteric soil bacteria from local dairy farms within Roosevelt County, NM, determined the resistance profiles to antibiotics associated with mar, such as chloramphenicol, nalidixic acid, penicillin G and tetracycline. We then purified and characterized plasmid DNA and detected mar phenotypic activity. The minimal inhibitory concentrations (MICs) of antibiotics for the isolates ranged between 6 - >50 μg/mL for chloramphenicol, 2–8 μg/mL for nalidixic acid, 25- >300 μg/mL for penicillin G and 1- > 80 μg/mL for tetracycline. On the other hand, the many of the isolates had significantly enhanced MICs for the same antibiotics in the presence of 5 mM salycilate. Plasmid DNA extracted from 12 randomly chosen isolates ranged in size between 6 and 12.5kb and in several cases conferred resistances to chloramphenicol and penicillin G. It is concluded that enteric bacteria from dairy farm topsoil are multi-drug resistant and harbor antibiotic resistance plasmids. A role for dairy topsoil in zoonosis is suggested, thus implicating this environment as a reservoir for bacterial resistance development against clinically relevant

  14. Clinical implications of the global multidrug-resistant tuberculosis epidemic.

    PubMed

    Kumar, Kartik; Abubakar, Ibrahim

    2015-12-01

    Multidrug-resistant tuberculosis (MDR TB) is a significant threat to global health estimated to account for nearly half a million new cases and over 200,000 deaths in 2013. The number of MDR TB cases in the UK has risen over the last 15 years, with ever more complex clinical cases and associated challenging public health and societal implications. In this review, we provide an overview of the epidemiology of MDR TB globally and in the UK, outline the clinical management of MDR TB and summarise recent advances in diagnostics and prospects for new treatment.

  15. Clonal distribution of multidrug-resistant Enterobacter cloacae.

    PubMed

    Girlich, Delphine; Poirel, Laurent; Nordmann, Patrice

    2015-04-01

    A multilocus sequence typing (MLST) scheme including 7 housekeeping genes was used to evaluate whether the current spread of multidrug-resistant Enterobacter cloacae isolates worldwide might be associated to specific successful clones. Fifty E. cloacae clinical isolates of worldwide origin, with various β-lactamase content, and recovered at different periods of time were studied. Forty-four sequence types were identified, highlighting a high clonal diversity with 3 main lineages. This study revealed that a precise identification of the isolates by sequencing of the chromosomal ampC gene of E. cloacae would provide a significant added value to improve the reliability of the MLST scheme.

  16. Enhancement of neutrophil autophagy by an IVIG preparation against multidrug-resistant bacteria as well as drug-sensitive strains.

    PubMed

    Itoh, Hiroshi; Matsuo, Hidemasa; Kitamura, Naoko; Yamamoto, Sho; Higuchi, Takeshi; Takematsu, Hiromu; Kamikubo, Yasuhiko; Kondo, Tadakazu; Yamashita, Kouhei; Sasada, Masataka; Takaori-Kondo, Akifumi; Adachi, Souichi

    2015-07-01

    Autophagy occurs in human neutrophils after the phagocytosis of multidrug-resistant bacteria and drug-sensitive strains, including Escherichia coli and Pseudomonas aeruginosa. The present study detected autophagy by immunoblot analysis of LC3B conversion, by confocal scanning microscopic examination of LC3B aggregate formation and by transmission electron microscopic examination of bacteria-containing autophagosomes. Patients with severe bacterial infections are often treated with IVIG alongside antimicrobial agents. Here, we showed that IVIG induced neutrophil-mediated phagocytosis of multidrug-resistant strains. Compared with untreated neutrophils, neutrophils exposed to IVIG showed increased levels of bacterial cell killing, phagocytosis, O(2)(-) release, MPO release, and NET formation. IVIG also increased autophagy in these cells. Inhibiting the late phase of autophagy (fusion of lysosomes with autophagosomes) with bafilomycin A1-reduced, neutrophil-mediated bactericidal activity. These findings indicate that autophagy plays a critical role in the bactericidal activity mediated by human neutrophils. Furthermore, the autophagosomes within the neutrophils contained bacteria only and their organelles only, or both bacteria and their organelles, a previously undocumented observation. Taken together, these results suggest that the contents of neutrophil autophagosomes may be derived from specific autophagic systems, which provide the neutrophil with an advantage. Thus, IVIG promotes the neutrophil-mediated killing of multidrug-resistant bacteria as well as drug-sensitive strains.

  17. Co-delivery nanoparticles with characteristics of intracellular precision release drugs for overcoming multidrug resistance

    PubMed Central

    Zhang, DanDan; Kong, Yan Yan; Sun, Jia Hui; Huo, Shao Jie; Zhou, Min; Gui, Yi Ling; Mu, Xu; Chen, Huan; Yu, Shu Qin; Xu, Qian

    2017-01-01

    Combination chemotherapy in clinical practice has been generally accepted as a feasible strategy for overcoming multidrug resistance (MDR). Here, we designed and successfully prepared a co-delivery system named S-D1@L-D2 NPs, where denoted some smaller nanoparticles (NPs) carrying a drug doxorubicin (DOX) were loaded into a larger NP containing another drug (vincristine [VCR]) via water-in-oil-in-water double-emulsion solvent diffusion-evaporation method. Chitosan-alginate nanoparticles carrying DOX (CS-ALG-DOX NPs) with a smaller diameter of about 20 nm formed S-D1 NPs; vitamin E D-α-tocopheryl polyethylene glycol 1000 succinate-modified poly(lactic-co-glycolic acid) nanoparticles carrying VCR (TPGS-PLGA-VCR NPs) with a larger diameter of about 200 nm constituted L-D2 NPs. Some CS-ALG-DOX NPs loaded into TPGS-PLGA-VCR NPs formed CS-ALG-DOX@TPGS-PLGA-VCR NPs. Under the acidic environment of cytosol and endosome or lysosome in MDR cell, CS-ALG-DOX@TPGS-PLGA-VCR NPs released VCR and CS-ALG-DOX NPs. VCR could arrest cell cycles at metaphase by inhibiting microtubule polymerization in the cytoplasm. After CS-ALG-DOX NPs escaped from endosome, they entered the nucleus through the nuclear pore and released DOX in the intra-nuclear alkaline environment, which interacted with DNA to stop the replication of MDR cells. These results indicated that S-D1@L-D2 NPs was a co-delivery system of intracellular precision release loaded drugs with pH-sensitive characteristics. S-D1@L-D2 NPs could obviously enhance the in vitro cytotoxicity and the in vivo anticancer efficiency of co-delivery drugs, while reducing their adverse effects. Overall, S-D1@L-D2 NPs can be considered an innovative platform for the co-delivery drugs of clinical combination chemotherapy for the treatment of MDR tumor. PMID:28356731

  18. Establishment of human tumoral ependymal cell lines and coculture with tubular-like human endothelial cells.

    PubMed

    Brisson, C; Lelong-Rebel, I; Mottolèse, C; Jouvet, A; Fèvre-Montange, M; Saint Pierre, G; Rebel, G; Belin, M F

    2002-10-01

    Ependymomas, rare neoplasms of the central nervous system, occur predominantly in children. They are highly vascularized, and histological findings show many perivascular rosettes of tumoral cells radially organized around capillaries. Treatment of ependymomas relies on surgery combined with radio- or chemotherapy, but the efficiency of chemotherapy is limited, probably because of their multidrug resistance (MDR) phenotype. Progress in the therapy of these neoplasms is dramatically limited by the absence of cell line models. We established conditions for the long-term culture of human tumoral ependymocytes and their 3D coculture in Matrigel with endothelial cells. Histological, immunological, and ultrastructural studies showed that the morphological features (microvilli, cilia, and caveolae) of these cultured cells were similar to those of the tumor in vivo. The cells expressed potential oncological markers related to the immature state of tumoral cells (nestin and Notch-1), their tumorigenicity [caveolae and epidermal growth factor-receptor (EGF-R)], or the MDR phenotype [P-glycoprotein (P-gp)]. The expression of P-gp, EGF-R, and caveolin-1 by these tumoral ependymocytes could be useful in studies on new drugs. This coculture model might represent a new powerful tool to study new therapeutic delivery strategies in tumoral cells.

  19. Regulation and expression of multidrug resistance (MDR) transcripts in the intestinal epithelium

    PubMed Central

    Li, M; Hurren, R; Zastawny, R L; Ling, V; Buick, R N

    1999-01-01

    A paucity of information exists on the regulation of gene expression in the undifferentiated intestine. The intestinal epithelium is one of the few normal tissues expressing the multidrug resistance (MDR) genes that confer the multidrug resistant phenotype to a variety of tumours. Expression of mdr1a has been observed in the primitive rat intestinal epithelial cell line, IEC-18. It is hypothesized that characterization of MDR gene expression in IEC-18 cells will provide insight into gene regulation in undifferentiated intestinal cells. A series of hamster mdr1a promoter deletion constructs was studied in IEC-18 and a region with 12–13-fold enhancer activity was identified. This region was shown to function in an orientation- and promoter context-independent manner, specifically in IEC-18 cells. Unexpectedly, Northern probing revealed a greater expression of mdr1b than mdr1a in IEC-18 cells. A quantitative reverse transcription polymerase chain reaction assay was used to compare the relative expression of MDR genes in IEC cells, fetal intestine, and in the undifferentiated and differentiated components of adult intestinal epithelium. MDR transcript levels in IEC cells were found to resemble those of fetal intestine and small intestinal crypts, where a conversion from mixed mdr1a/mdr1b to predominantly mdr1a expression occurs as cells mature. This work describes two contributions to the field of gene regulation in the undifferentiated intestine – first, the initial characterization of a putative mdr1a enhancer region with specificity for primitive intestinal cells and secondly, the first report of mdr1b detection in the intestine and its expression in primitive cell types. © 1999 Cancer Research Campaign PMID:10376961

  20. In vitro and in vivo analysis of antimicrobial agents alone and in combination against multi-drug resistant Acinetobacter baumannii

    PubMed Central

    He, Songzhe; He, Hui; Chen, Yi; Chen, Yueming; Wang, Wei; Yu, Daojun

    2015-01-01

    Objective: To investigate the in vitro and in vivo antibacterial activities of tigecycline and other 13 common antimicrobial agents, alone or in combination, against multi-drug resistant Acinetobacter baumannii. Methods: An in vitro susceptibility test of 101 A. baumannii was used to detect minimal inhibitory concentrations (MICs). A mouse lung infection model of multi-drug resistant A. baumannii, established by the ultrasonic atomization method, was used to define in vivo antimicrobial activities. Results: Multi-drug resistant A. baumannii showed high sensitivity to tigecycline (98% inhibition), polymyxin B (78.2% inhibition), and minocycline (74.2% inhibition). However, the use of these antimicrobial agents in combination with other antimicrobial agents produced synergistic or additive effects. In vivo data showed that white blood cell (WBC) counts in drug combination groups C (minocycline + amikacin) and D (minocycline + rifampicin) were significantly higher than in groups A (tigecycline) and B (polymyxin B) (P < 0.05), after administration of the drugs 24 h post-infection. Lung tissue inflammation gradually increased in the model group during the first 24 h after ultrasonic atomization infection; vasodilation, congestion with hemorrhage were observed 48 h post infection. After 3 days of anti-infective therapy in groups A, B, C, and D, lung tissue inflammation in each group gradually recovered with clear structures. The mortality rates in drug combination groups(groups C and D) were much lower than in groups A and B. Conclusion: The combination of minocycline with either rifampicin or amikacin is more effective against multi-drug resistant A. baumannii than single-agent tigecycline or polymyxin B. In addition, the mouse lung infection by ultrasonic atomization is a suitable model for drug screening and analysis of infection mechanism. PMID:26074898

  1. Multidrug resistance in cancer chemotherapy and xenobiotic protection mediated by the half ATP-binding cassette transporter ABCG2.

    PubMed

    Han, B; Zhang, J-T

    2004-01-01

    ABCG2, also termed BCRP/MXR/ABCP, is a half ATP-binding cassette (ABC) transporter expressed on plasma membranes. ABCG2 was independently cloned from placenta as well as cell lines selected for resistance to mitoxantrone or anthracyclines. ABCG2 consists of a nucleotide-binding domain (NBD) at the amino terminus and a transmembrane domain (TMD) at the carboxyl terminus and it is postulated to form a homodimer to perform its biological functions. Over-expression of ABCG2 in cell lines confers resistance on a wide variety of anticancer drugs including mitoxantrone, daunorubicin, doxorubicin, topotecan and epirubicin. The expression of ABCG2 has been implicated in multidrug resistance (MDR) of acute myeloid leukemia and some solid tumors. In addition, ABCG2 can transport several fluorescent dyes or toxins. ABCG2 is found to be expressed in epithelial cells of intestine and colon, liver canaliculi, and renal tubules, where it serves to eliminate the plasma level of orally administered anticancer drugs as well as ingested toxins. ABCG2 is found to be highly expressed in placenta and the luminal surface of microvessel endothelium blood-brain barrier where it may play a role in limiting the penetration of drugs, such as topotecan from the maternal plasma into the fetus and from blood to brain. A variety of inhibitors for ABCG2 including GF120918 may prove useful for sensitizing cancer cells to chemotherapy or altering the distribution of orally administered drug substrates of ABCG2. Interestingly, ABCG2 is also expressed highly in hematopoietic stem cells. However, the function of ABCG2 in stem cells is currently unknown, although it may provide protection to stem cells from a variety of xenobiotics.

  2. Multidrug resistance protein gene expression in Trichoplusia ni caterpillars.

    PubMed

    Simmons, Jason; D'Souza, Olivia; Rheault, Mark; Donly, Cam

    2013-02-01

    Many insect species exhibit pesticide-resistant phenotypes. One of the mechanisms capable of contributing to resistance is the overexpression of multidrug resistance (MDR) transporter proteins. Here we describe the cloning of three genes encoding MDR proteins from Trichoplusia ni: trnMDR1, trnMDR2 and trnMDR3. Real-time quantitative PCR (qPCR) detected trnMDR mRNA in the whole nervous system, midgut and Malpighian tubules of final instar T. ni caterpillars. To test whether these genes are upregulated in response to chemical challenge in this insect, qPCR was used to compare trnMDR mRNA levels in unchallenged insects with those of insects fed the synthetic pyrethroid, deltamethrin. Only limited increases were detected in a single gene, trnMDR2, which is the most weakly expressed of the three MDR genes, suggesting that increased multidrug resistance of this type is not a significant part of the response to deltamethrin exposure.

  3. The secondary resistome of multidrug-resistant Klebsiella pneumoniae

    PubMed Central

    Jana, Bimal; Cain, Amy K.; Doerrler, William T.; Boinett, Christine J.; Fookes, Maria C.; Parkhill, Julian; Guardabassi, Luca

    2017-01-01

    Klebsiella pneumoniae causes severe lung and bloodstream infections that are difficult to treat due to multidrug resistance. We hypothesized that antimicrobial resistance can be reversed by targeting chromosomal non-essential genes that are not responsible for acquired resistance but essential for resistant bacteria under therapeutic concentrations of antimicrobials. Conditional essentiality of individual genes to antimicrobial resistance was evaluated in an epidemic multidrug-resistant clone of K. pneumoniae (ST258). We constructed a high-density transposon mutant library of >430,000 unique Tn5 insertions and measured mutant depletion upon exposure to three clinically relevant antimicrobials (colistin, imipenem or ciprofloxacin) by Transposon Directed Insertion-site Sequencing (TraDIS). Using this high-throughput approach, we defined three sets of chromosomal non-essential genes essential for growth during exposure to colistin (n = 35), imipenem (n = 1) or ciprofloxacin (n = 1) in addition to known resistance determinants, collectively termed the “secondary resistome”. As proof of principle, we demonstrated that inactivation of a non-essential gene not previously found linked to colistin resistance (dedA) restored colistin susceptibility by reducing the minimum inhibitory concentration from 8 to 0.5 μg/ml, 4-fold below the susceptibility breakpoint (S ≤ 2 μg/ml). This finding suggests that the secondary resistome is a potential target for developing antimicrobial “helper” drugs that restore the efficacy of existing antimicrobials. PMID:28198411

  4. The secondary resistome of multidrug-resistant Klebsiella pneumoniae.

    PubMed

    Jana, Bimal; Cain, Amy K; Doerrler, William T; Boinett, Christine J; Fookes, Maria C; Parkhill, Julian; Guardabassi, Luca

    2017-02-15

    Klebsiella pneumoniae causes severe lung and bloodstream infections that are difficult to treat due to multidrug resistance. We hypothesized that antimicrobial resistance can be reversed by targeting chromosomal non-essential genes that are not responsible for acquired resistance but essential for resistant bacteria under therapeutic concentrations of antimicrobials. Conditional essentiality of individual genes to antimicrobial resistance was evaluated in an epidemic multidrug-resistant clone of K. pneumoniae (ST258). We constructed a high-density transposon mutant library of >430,000 unique Tn5 insertions and measured mutant depletion upon exposure to three clinically relevant antimicrobials (colistin, imipenem or ciprofloxacin) by Transposon Directed Insertion-site Sequencing (TraDIS). Using this high-throughput approach, we defined three sets of chromosomal non-essential genes essential for growth during exposure to colistin (n = 35), imipenem (n = 1) or ciprofloxacin (n = 1) in addition to known resistance determinants, collectively termed the "secondary resistome". As proof of principle, we demonstrated that inactivation of a non-essential gene not previously found linked to colistin resistance (dedA) restored colistin susceptibility by reducing the minimum inhibitory concentration from 8 to 0.5 μg/ml, 4-fold below the susceptibility breakpoint (S ≤ 2 μg/ml). This finding suggests that the secondary resistome is a potential target for developing antimicrobial "helper" drugs that restore the efficacy of existing antimicrobials.

  5. Molecular Mimics of Classic P-Glycoprotein Inhibitors as Multidrug Resistance Suppressors and Their Synergistic Effect on Paclitaxel

    PubMed Central

    Omar, Abdelsattar M.; Khayat, Maan T.; Assiri, Hanan A.; Al-Abd, Ahmed M.

    2017-01-01

    P-glycoprotein (Pgp) is a membrane bound efflux pump spread in a variety of tumor cells and considered as a main component of multidrug resistance (MDR) to chemotherapies. In this work, three groups of compounds (imidazolone, oxazolone and vinyl dipeptide derivatives) were synthesized aiming to develop a molecular framework that effectively suppresses MDR. When tested for their influence on Pgp activity, four compounds coded Cur1-01, Cur1-12V, Curox-1 and Curox-3 significantly decreased remaining ATP concentration indicating Pgp substrate site blocking. On the other hand, Cur-3 and Cur-10 significantly increased remaining ATP concentration, which is indicative of Pgp ATPase inhibition. The cytotoxicity of synthesized compounds was examined against Pgp expressing/highly resistant colorectal cancer cell lines (LS-174T). Compounds Cur-1 and Cur-3 showed considerable cytotoxicity with IC50 values of 7.6 and 8.9 μM, respectively. Equitoxic combination (at IC50 concentrations) of PTX and Cur-3 greatly diminished resistant cell clone from 45.7% to 2.5%, albeit with some drop in potency from IC50 of 7.9 nM to IC50 of 23.8 nM. On the other hand, combination of PTX and the non-cytotoxic Cur1-12V (10 μM) significantly decreased the IC50 of PTX to 3.8 nM as well as the resistant fraction to 16.2%. The combination test was confirmed using the same protocol but on another resistant CRC cell line (HCT-116) as we obtained similar results. Both Cur-3 and Cur1-12V (10 μM) significantly increased the cellular entrapment of Pgp probe (doxorubicin) elevating its intracellular concentration from 1.9 pmole/cell to 3.0 and 2.9 pmole/cell, respectively. PMID:28068430

  6. Worldwide Endemicity of a Multidrug-Resistant Staphylococcus capitis Clone Involved in Neonatal Sepsis

    PubMed Central

    Martins-Simões, Patricia; Rasigade, Jean-Philippe; Picaud, Jean-Charles; Laurent, Frédéric

    2017-01-01

    A multidrug-resistant Staphylococcus capitis clone, NRCS-A, has been isolated from neonatal intensive care units in 17 countries throughout the world. S. capitis NRCS-A prevalence is high in some neonatal intensive care units in France. These data highlight the worldwide endemicity and epidemiologic relevance of this multidrug-resistant, coagulase-negative staphylococci clone. PMID:28221122

  7. Human Multidrug-Resistant Salmonella Newport Infections, Wisconsin, 2003–2005

    PubMed Central

    Archer, John R.; Sotir, Mark J.; Monson, Timothy A.; Kazmierczak, James J.

    2007-01-01

    We conducted a retrospective study of Salmonella Newport infections among Wisconsin residents during 2003–2005. Multidrug resistance prevalence was substantially greater in Wisconsin than elsewhere in the United States. Persons with multidrug-resistant infections were more likely than persons with susceptible infections to report exposure to cattle, farms, and unpasteurized milk. PMID:18217570

  8. Natural History of Multi-Drug Resistant Organisms in a New Military Medical Facility

    DTIC Science & Technology

    2013-12-01

    Staphylococcus saprophyticus 14 (3) Enterococcus (faecium and faecalis) 11 (2) The remaining 11 species each comprised less than 2% of total 169 (32...environment plays in the transmission of multidrug-resistant Gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MDRO) is increasingly...Pseudomonas aeruginosa, methicillin- resistant Staphylococcus aureus (MRSA); Klebsiella pneumoniea; and Clostridium difficile. Multidrug- resistance (MDR

  9. Undetected multidrug-resistant tuberculosis amplified by first-line therapy in mixed infection.

    PubMed

    Hingley-Wilson, Suzanne M; Casey, Rosalyn; Connell, David; Bremang, Samuel; Evans, Jason T; Hawkey, Peter M; Smith, Grace E; Jepson, Annette; Philip, Stuart; Kon, Onn Min; Lalvani, Ajit

    2013-07-01

    Infections with >1 Mycobacterium tuberculosis strain(s) are underrecognized. We show, in vitro and in vivo, how first-line treatment conferred a competitive growth advantage to amplify a multidrug-resistant M. tuberculosis strain in a patient with mixed infection. Diagnostic techniques that identify mixed tubercle bacilli populations are needed to curb the spread of multidrug resistance.

  10. Use of Spatial Information to Predict Multidrug Resistance in Tuberculosis Patients, Peru

    PubMed Central

    Lin, Hsien-Ho; Shin, Sonya S.; Contreras, Carmen; Asencios, Luis; Paciorek, Christopher J.

    2012-01-01

    To determine whether spatiotemporal information could help predict multidrug resistance at the time of tuberculosis diagnosis, we investigated tuberculosis patients who underwent drug susceptibility testing in Lima, Peru, during 2005–2007. We found that crude representation of spatial location at the level of the health center improved prediction of multidrug resistance. PMID:22516236

  11. Therapeutic Efficacy and Safety of Paclitaxel/Lonidamine Loaded EGFR-Targeted Nanoparticles for the Treatment of Multi-Drug Resistant Cancer

    PubMed Central

    Milane, Lara; Duan, Zhenfeng; Amiji, Mansoor

    2011-01-01

    The treatment of multi-drug resistant (MDR) cancer is a clinical challenge. Many MDR cells over-express epidermal growth factor receptor (EGFR). We exploit this expression through the development of EGFR-targeted, polymer blend nanocarriers for the treatment of MDR cancer using paclitaxel (a common chemotherapeutic agent) and lonidamine (an experimental drug; mitochondrial hexokinase 2 inhibitor). An orthotopic model of MDR human breast cancer was developed in nude mice and used to evaluate the safety and efficacy of nanoparticle treatment. The efficacy parameters included tumor volume measurements from day 0 through 28 days post-treatment, terminal tumor weight measurements, tumor density and morphology assessment through hematoxylin and eosin staining of excised tumors, and immunohistochemistry of tumor sections for MDR protein markers (P-glycoprotein, Hypoxia Inducible Factor, EGFR, Hexokinase 2, and Stem Cell Factor). Toxicity was assessed by tracking changes in animal body weight from day 0 through 28 days post-treatment, by measuring plasma levels of the liver enzymes ALT (Alanine Aminotransferase) and LDH (lactate dehydrogenase), and by white blood cell and platelet counts. In these studies, this nanocarrier system demonstrated superior efficacy relative to combination (paclitaxel/lonidamine) drug solution and single agent treatments in nanoparticle and solution form. The combination nanoparticles were the only treatment group that decreased tumor volume, sustaining this decrease until the 28 day time point. In addition, treatment with the EGFR-targeted lonidamine/paclitaxel nanoparticles decreased tumor density and altered the MDR phenotype of the tumor xenografts. These EGFR-targeted combination nanoparticles were considerably less toxic than solution treatments. Due to the flexible design and simple conjugation chemistry, this nanocarrier system could be used as a platform for the development of other MDR cancer therapies; the use of this system for EGFR

  12. What do proton motive force driven multidrug resistance transporters have in common?

    PubMed

    Mazurkiewicz, Piotr; Driessen, Arnold J M; Konings, Wil N

    2005-01-01

    The extensive progress of genome sequencing projects in recent years has demonstrated that multidrug resistance (MDR) transporters are widely spread among all domains of life. This indicates that they play crucial roles in the survival of organisms. Moreover, antibiotic and chemotherapeutic treatments have revealed that microorganisms and cancer cells may use MDR transporters to fight the cytotoxic action of drugs. Currently, several MDR extrusion systems are being investigated in detail. It is expected that understanding of the molecular basis of multidrug recognition and the transport mechanisms will allow a more rational design of new drugs which either will not be recognized and expelled by or will efficiently inhibit the activity of the MDR transporters. MDR transporters either utilize ATP hydrolysis or an ion motive force as an energy source to drive drugs out of the cell. This review summarizes the recent progress in the field of bacterial proton motive force driven MDR transporters.

  13. Supramolecular Cationic Assemblies against Multidrug-Resistant Microorganisms: Activity and Mechanism of Action

    PubMed Central

    de Melo Carrasco, Letícia Dias; Sampaio, Jorge Luiz Mello; Carmona-Ribeiro, Ana Maria

    2015-01-01

    The growing challenge of antimicrobial resistance to antibiotics requires novel synthetic drugs or new formulations for old drugs. Here, cationic nanostructured particles (NPs) self-assembled from cationic bilayer fragments and polyelectrolytes are tested against four multidrug-resistant (MDR) strains of clinical importance. The non-hemolytic poly(diallyldimethylammonium) chloride (PDDA) polymer as the outer NP layer shows a remarkable activity against these organisms. The mechanism of cell death involves bacterial membrane lysis as determined from the leakage of inner phosphorylated compounds and possibly disassembly of the NP with the appearance of multilayered fibers made of the NP components and the biopolymers withdrawn from the cell wall. The NPs display broad-spectrum activity against MDR microorganisms, including Gram-negative and Gram-positive bacteria and yeast. PMID:25809608

  14. Expression of MDR1 (multidrug resistance) gene and its protein in normal human kidney.

    PubMed

    Ernest, S; Rajaraman, S; Megyesi, J; Bello-Reuss, E N

    1997-01-01

    P-glycoprotein (Pgp), the product of the multidrug resistance (MDR) gene overexpressed in cancer cells, is present also in normal tissues. In the kidney, MDR1 Pgp has been found in the proximal tubule and in cultured mesangial cells. In situ hybridization and immunohistochemistry were used to determine the complete nephronal localization of MDR mRNA and its product, Pgp, in the human kidney. MDR mRNA expression was studied with the use of nonradioactive in situ MDR RNA probes. MDR1 Pgp was immunolocalized using the specific monoclonal antibody MRK16. The presence of MDR mRNA was confirmed in proximal tubules and mesangium, and demonstrated as well in thick limb of Henle's loops and in collecting ducts. MDR1 Pgp colocalized in the same nephronal segments. This suggests that, in addition to secreting xenobiotics, Pgp may play a role in the transport of endogenous substrates or in the regulation of Cl- channels.

  15. Kinetics of MDR Transport in Tumor-Initiating Cells

    PubMed Central

    Koshkin, Vasilij; Yang, Burton B.; Krylov, Sergey N.

    2013-01-01

    Multidrug resistance (MDR) driven by ABC (ATP binding cassette) membrane transporters is one of the major causes of treatment failure in human malignancy. MDR capacity is thought to be unevenly distributed among tumor cells, with higher capacity residing in tumor-initiating cells (TIC) (though opposite finding are occasionally reported). Functional evidence for enhanced MDR of TICs was previously provided using a “side population” assay. This assay estimates MDR capacity by a single parameter - cell’s ability to retain fluorescent MDR substrate, so that cells with high MDR capacity (“side population”) demonstrate low substrate retention. In the present work MDR in TICs was investigated in greater detail using a kinetic approach, which monitors MDR efflux from single cells. Analysis of kinetic traces obtained allowed for the estimation of both the velocity (Vmax) and affinity (KM) of MDR transport in single cells. In this way it was shown that activation of MDR in TICs occurs in two ways: through the increase of Vmax in one fraction of cells, and through decrease of KM in another fraction. In addition, kinetic data showed that heterogeneity of MDR parameters in TICs significantly exceeds that of bulk cells. Potential consequences of these findings for chemotherapy are discussed. PMID:24223908

  16. Turning the gun on cancer: Utilizing lysosomal P-glycoprotein as a new strategy to overcome multi-drug resistance.

    PubMed

    Seebacher, Nicole; Lane, Darius J R; Richardson, Des R; Jansson, Patric J

    2016-07-01

    Oxidative stress plays a role in the development of drug resistance in cancer cells. Cancer cells must constantly and rapidly adapt to changes in the tumor microenvironment, due to alterations in the availability of nutrients, such as glucose, oxygen and key transition metals (e.g., iron and copper). This nutrient flux is typically a consequence of rapid growth, poor vascularization and necrosis. It has been demonstrated that stress factors, such as hypoxia and glucose deprivation up-regulate master transcription factors, namely hypoxia inducible factor-1α (HIF-1α), which transcriptionally regulate the multi-drug resistance (MDR), transmembrane drug efflux transporter, P-glycoprotein (Pgp). Interestingly, in addition to the established role of plasma membrane Pgp in MDR, a new paradigm of intracellular resistance has emerged that is premised on the ability of lysosomal Pgp to transport cytotoxic agents into this organelle. This mechanism is enabled by the topological inversion of Pgp via endocytosis resulting in the transporter actively pumping agents into the lysosome. In this way, classical Pgp substrates, such as doxorubicin (DOX), can be actively transported into this organelle. Within the lysosome, DOX becomes protonated upon acidification of the lysosomal lumen, causing its accumulation. This mechanism efficiently traps DOX, preventing its cytotoxic interaction with nuclear DNA. This review discusses these effects and highlights a novel mechanism by which redox-active and protonatable Pgp substrates can utilize lysosomal Pgp to gain access to this compartment, resulting in catastrophic lysosomal membrane permeabilization and cell death. Hence, a key MDR mechanism that utilizes Pgp (the "gun") to sequester protonatable drug substrates safely within lysosomes can be "turned on" MDR cancer cells to destroy them from within.

  17. Preparation of silver nanoparticles fabrics against multidrug-resistant bacteria

    NASA Astrophysics Data System (ADS)

    Hanh, Truong Thi; Thu, Nguyen Thi; Hien, Nguyen Quoc; An, Pham Ngoc; Loan, Truong Thi Kieu; Hoa, Phan Thi

    2016-04-01

    The silver nanoparticles (AgNPs)/peco fabrics were prepared by immobilization of AgNPs on fabrics in which AgNPs were synthesized by γ-irradiation of the 10 mM AgNO3 chitosan solution at the dose of 17.6 kGy. The AgNPs size has been estimated to be about 11 nm from TEM image. The AgNPs content onto peco fabrics was of 143±6 mg/kg at the initial AgNPs concentration of 100 ppm. The AgNPs colloidal solution was characterized by UV-vis spectroscopy and TEM image. The antibacterial activity of AgNPs/peco fabrics after 60 washings against Staphylococcus aureus and Klebsiella pneumoniae was found to be over 99%. Effects of AgNPs fabics on multidrug-resistant pathogens from the clinical specimens were also tested.

  18. Bacteriophages: biosensing tools for multi-drug resistant pathogens.

    PubMed

    Tawil, N; Sacher, E; Mandeville, R; Meunier, M

    2014-03-21

    Pathogen detection is of utmost importance in many sectors, such as in the food industry, environmental quality control, clinical diagnostics, bio-defence and counter-terrorism. Failure to appropriately, and specifically, detect pathogenic bacteria can lead to serious consequences, and may ultimately be lethal. Public safety, new legislation, recent outbreaks in food contamination, and the ever-increasing prevalence of multidrug-resistant infections have fostered a worldwide research effort targeting novel biosensing strategies. This review concerns phage-based analytical and biosensing methods targeted towards theranostic applications. We discuss and review phage-based assays, notably phage amplification, reporter phage, phage lysis, and bioluminescence assays for the detection of bacterial species, as well as phage-based biosensors, including optical (comprising SPR sensors and fiber optic assays), electrochemical (comprising amperometric, potentiometric, and impedimetric sensors), acoustic wave and magnetoelastic sensors.

  19. [Multidrug-resistant tuberculosis. Epidemiology, treatment, prevention and diagnostic research].

    PubMed

    Perronne, C; de Truchis, P

    1995-01-01

    The recent augmentation of the prevalence of multidrug resistant (MDR) tuberculosis is related to the high incidence of tuberculosis in HIV infected people, especially in those with low social status and no medical care; several nosocomial epidemics of MDR tuberculosis were observed in American and European institutions where HIV-infected persons were hospitalized; these MDR tuberculosis were associated with a high mortality-rate and frequent nosocomial transmission to immunocompromised contacts and care workers. The rapid institution of an adequate treatment with ancient antituberculosis agents (cycloserin, capreomycin, aminoglycosides) and/or new drugs (rifabutine, ofloxacin, sparfloxacin, etc) is necessary to avoid mortality and to diminish transmission. Prevention of MDR tuberculosis transmission is very important: patient isolation, adequate and prolonged therapy, better detection of resistance with gene-amplification methods (PCR) which are under investigation.

  20. Clusters of Multidrug-Resistant Mycobacterium tuberculosis Cases, Europe

    PubMed Central

    Kremer, Kristin; Heersma, Herre; Van Soolingen, Dick

    2009-01-01

    Molecular surveillance of multidrug-resistant tuberculosis (MDR TB) was implemented in Europe as case reporting in 2005. For all new MDR TB cases detected from January 2003 through June 2007, countries reported case-based epidemiologic data and DNA fingerprint patterns of MDR TB strains when available. International clusters were detected and analyzed. From 2003 through mid-2007 in Europe, 2,494 cases of MDR TB were reported from 24 European countries. Epidemiologic and molecular data were linked for 593 (39%) cases, and 672 insertion sequence 6110 DNA fingerprint patterns were reported from 19 countries. Of these patterns, 288 (43%) belonged to 18 European clusters; 7 clusters (242/288 cases, 84%) were characterized by strains of the Beijing genotype family, including the largest cluster (175/288 cases, 61%). Both clustering and the Beijing genotype were associated with strains originating in eastern European countries. Molecular cluster detection contributes to identification of transmission profile, risk factors, and control measures. PMID:19624920

  1. Breaking the Spell: Combating Multidrug Resistant ‘Superbugs’

    PubMed Central

    Khan, Shahper N.; Khan, Asad U.

    2016-01-01

    Multidrug-resistant (MDR) bacteria have become a severe threat to community wellbeing. Conventional antibiotics are getting progressively more ineffective as a consequence of resistance, making it imperative to realize improved antimicrobial options. In this review we emphasized the microorganisms primarily reported of being resistance, referred as ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanii, Pseudomonas aeruginosa, and Enterobacteriaceae) accentuating their capacity to “escape” from routine antimicrobial regimes. The upcoming antimicrobial agents showing great potential and can serve as alternative therapeutic options are discussed. We also provided succinct overview of two evolving technologies; specifically network pharmacology and functional genomics profiling. Furthermore, In vivo imaging techniques can provide novel targets and a real time tool for potential lead molecule assessment. The employment of such approaches at prelude of a drug development process, will enables more informed decisions on candidate drug selection and will maximize or predict therapeutic potential before clinical testing. PMID:26925046

  2. Role of serum interleukin-6 in deciding therapy for multidrug resistant oral lichen planus

    PubMed Central

    Marwah, Akanksha; Kaushik, Smita; Garg, Vijay K.; Gupta, Sunita

    2015-01-01

    Background Oral lichen planus (OLP) is a T cell mediated immune response. T cells locally present in the involved tissues release cytokines like interleukin-6 (IL-6), which contributes to pathogenesis of OLP. Also IL-6 has been associated with multidrug resistance protein (MRP) expression by keratinocytes. Correspondingly, upregulation of MRP was found in OLP. We conducted this study to evaluate the effects of various drugs on serum IL-6 in OLP; and correlation of these effects with the nature of clinical response and resistance pattern seen in OLP lesions with various therapeutic modalities. Thus we evaluated the role of serum IL-6 in deciding therapy for multidrug resistant OLP. Material and Methods Serum IL-6 was evaluated in 42 erosive OLP (EOLP) patients and 10 normal mucosa and 10 oral squamous cell carcinoma cases using ELISA technique. OLP patients were randomly divided into 3 groups of 14 patients each and were subjected to Pimecrolimus local application, oral Mycophenolate Mofetil (MMF) and Methotrexate (MTX) alongwith Pimecrolimus local application. IL-6 levels were evaluated before and after treatment. Results Serum IL-6 levels were raised above 3pg/ml in 26.19% erosive OLP (EOLP) cases (mean- 3.72±8.14). EOLP (5%) cases with IL-6 levels above 5pg/ml were resistant in MTX group. However significant decrease in serum IL-6 corresponding with the clinical resolution was seen in MMF group. Conclusions Significantly raised IL-6 levels in EOLP reflect the chronic inflammatory nature of the disease. As serum IL-6 levels significantly decreased in MMF group, correspondingly no resistance to treatment was noted. However with MTX there was no significant decrease in IL-6 and resistance to treatment was noted in some, especially plaque type lesions. Thus IL-6 can be a possible biomarker in deciding the best possible therapy for treatment resistant OLP. Key words:Lichen planus, biological markers, cytokines, enzyme-linked immunosorbent assay, immunosuppressive

  3. Osimertinib (AZD9291) Attenuates the Function of Multidrug Resistance-Linked ATP-Binding Cassette Transporter ABCB1 in Vitro.

    PubMed

    Hsiao, Sung-Han; Lu, Yu-Jen; Li, Yan-Qing; Huang, Yang-Hui; Hsieh, Chia-Hung; Wu, Chung-Pu

    2016-06-06

    The effectiveness of cancer chemotherapy is often circumvented by multidrug resistance (MDR) caused by the overexpression of ATP-binding cassette (ABC) drug transporter ABCB1 (MDR1, P-glycoprotein). Several epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been shown previously capable of modulating the function of ABCB1 and reversing ABCB1-mediated MDR in human cancer cells. Furthermore, some TKIs are transported by ABCB1, which results in low oral bioavailability, reduced distribution, and the development of acquired resistance to these TKIs. In this study, we investigated the interaction between ABCB1 and osimertinib, a novel selective, irreversible third-generation EGFR TKI that has recently been approved by the U.S. Food and Drug Administration. We also evaluated the potential impact of ABCB1 on the efficacy of osimertinib in cancer cells, which can present a therapeutic challenge to clinicians in the future. We revealed that although osimertinib stimulates the ATPase activity of ABCB1, overexpression of ABCB1 does not confer resistance to osimertinib. Our results suggest that it is unlikely that the overexpression of ABCB1 can be a major contributor to the development of osimertinib resistance in cancer patients. More significantly, we revealed an additional action of osimertinib that directly inhibits the function of ABCB1 without affecting the expression level of ABCB1, enhances drug-induced apoptosis, and reverses the MDR phenotype in ABCB1-overexpressing cancer cells. Considering that osimertinib is a clinically approved third-generation EGFR TKI, our findings suggest that a combination therapy with osimertinib and conventional anticancer drugs may be beneficial to patients with MDR tumors.

  4. Human ABCG2: structure, function, and its role in multidrug resistance

    PubMed Central

    Mo, Wei; Zhang, Jian-Ting

    2012-01-01

    Human ABCG2 is a member of the ATP-binding cassette (ABC) transporter superfamily and is known to contribute to multidrug resistance (MDR) in cancer chemotherapy. Among ABC transporters that are known to cause MDR, ABCG2 is particularly interesting for its potential role in protecting cancer stem cells and its complex oligomeric structure. Recent studies have also revealed that the biogenesis of ABCG2 could be modulated by small molecule compounds. These modulators, upon binding to ABCG2, accelerate the endocytosis and trafficking to lysosome for degradation and effectively reduce the half-life of ABCG2. Hence, targeting ABCG2 stability could be a new venue for therapeutic discovery to sensitize drug resistant human cancers. In this report, we review recent progress on understanding the structure, function, biogenesis, as well as physiological and pathophysiological functions of ABCG2. PMID:22509477

  5. Importance of detecting multidrug resistance proteins in acute leukemia prognosis and therapy.

    PubMed

    de Moraes, Ana Carolina Rabello; Maranho, Caroline Klein; Rauber, Gabriela Schneider; Santos-Silva, Maria Cláudia

    2013-01-01

    Multidrug resistance (MDR) is a multifactorial phenomenon and the role of these proteins in generating the MDR phenotype is controversial. With this in mind, this review compiled the current data on the role of ABCB1, ABCC1, and LRP proteins in the prognosis of hematologic neoplasms and their influence on the choice of therapy. Literature showed that the detection of these proteins, mainly ABCB1, is important in the AL prognosis. However, there is controversy regarding the methodology used for their detection. In summary, the expression and activity profiles of ABCB1, ABCC1, and LRP, proteins capable of promoting the efflux of a variety of chemotherapeutic agents from the cell cytoplasm represent one of the greatest causes of failure in AL treatment.

  6. Enhanced therapeutic effect of Adriamycin on multidrug resistant breast cancer by the ABCG2-siRNA loaded polymeric nanoparticles assisted with ultrasound

    PubMed Central

    Teng, Yanwei; Sun, Ying; Li, Fan; Zhang, Xiangyu; Xu, Yuanyuan; Duan, Yourong; Du, Lianfang

    2015-01-01

    The overexpression of the breast cancer resistance protein (ABCG2) confers resistance to Adriamycin (ADR) in breast cancer. The silencing of ABCG2 using small interfering RNA (siRNA) could be a promising approach to overcome multidrug resistance (MDR) in cancer cells. To deliver ABCG2-siRNA effectively into breast cancer cells, we used mPEG-PLGA-PLL (PEAL) nanoparticles (NPs) with ultrasound-targeted microbubble destruction (UTMD). PEAL NPs were prepared with an emulsion-solvent evaporation method. The NPs size was about 131.5 ± 6.5 nm. The siRNA stability in serum was enhanced. The intracellular ADR concentration increased after the introduction of siRNA-loaded NPs. After intravenous injection of PEAL NPs in tumor-bearing mice, the ABCG2-siRNA-loaded NPs with UTMD efficiently silenced the ABCG2 gene and enhanced the ADR susceptibility of MCF-7/ADR (ADR resistant human breast cancer cells). The siRNA-loaded NPs with UTMD + ADR showed better tumor inhibition effect and good safety in vivo. These results indicate that ADR-chemotherapy in combination with ABCG2-siRNA is an attractive strategy to treat breast cancer. PMID:26575421

  7. Glutathione-mediated antioxidant response and aerobic metabolism: two crucial factors involved in determining the multi-drug resistance of high-risk neuroblastoma

    PubMed Central

    Colla, Renata; Izzotti, Alberto; De Ciucis, Chiara; Fenoglio, Daniela; Ravera, Silvia; Speciale, Andrea; Ricciarelli, Roberta; Furfaro, Anna Lisa; Pulliero, Alessandra; Passalacqua, Mario; Traverso, Nicola; Pronzato, Maria Adelaide; Domenicotti, Cinzia; Marengo, Barbara

    2016-01-01

    Neuroblastoma, a paediatric malignant tumor, is initially sensitive to etoposide, a drug to which many patients develop chemoresistance. In order to investigate the molecular mechanisms responsible for etoposide chemoresistance, HTLA-230, a human MYCN-amplified neuroblastoma cell line, was chronically treated with etoposide at a concentration that in vitro mimics the clinically-used dose. The selected cells (HTLA-Chr) acquire multi-drug resistance (MDR), becoming less sensitive than parental cells to high doses of etoposide or doxorubicin. MDR is due to several mechanisms that together contribute to maintaining non-toxic levels of H2O2. In fact, HTLA-Chr cells, while having an efficient aerobic metabolism, are also characterized by an up-regulation of catalase activity and higher levels of reduced glutathione (GSH), a thiol antioxidant compound. The combination of such mechanisms contributes to prevent membrane lipoperoxidation and cell death. Treatment of HTLA-Chr cells with L-Buthionine-sulfoximine, an inhibitor of GSH biosynthesis, markedly reduces their tumorigenic potential that is instead enhanced by the exposure to N-Acetylcysteine, able to promote GSH synthesis. Collectively, these results demonstrate that GSH and GSH-related responses play a crucial role in the acquisition of MDR and suggest that GSH level monitoring is an efficient strategy to early identify the onset of drug resistance and to control the patient's response to therapy. PMID:27683112

  8. Safety and effectiveness of home intravenous antibiotic therapy for multidrug-resistant bacterial infections.

    PubMed

    Mujal, A; Sola, J; Hernandez, M; Villarino, M-A; Machado, M-L; Baylina, M; Tajan, J; Oristrell, J

    2015-06-01

    Home intravenous antibiotic therapy is an alternative to hospital admission for moderately severe infections. However, few studies have analyzed its safety and effectiveness in the treatment of infections caused by multidrug-resistant bacteria. The purpose of this study is to analyze the safety and effectiveness of home intravenous antibiotic therapy in multidrug-resistant bacterial infections. We analyzed prospectively all patients admitted to our service who underwent home intravenous antibiotic therapy during the period 2008-2012. All the treatments were administered by caretakers or self-administered by patients, through elastomeric infusion devices. Effectiveness was evaluated by analyzing the readmission rate for poor infection control. Safety was evaluated by analyzing adverse events, catheter-related complications, and readmissions not related to poor infection control. There were 433 admissions (in 355 patients) for home intravenous antibiotic therapy during the study period. There were 226 (52.2 %) admissions due to multidrug-resistant bacterial infections and 207 (47.8 %) due to non-multidrug-resistant infections. Hospital readmissions in patients with multidrug-resistant infections were uncommon. Multidrug-resistant enterococcal infections, healthcare-associated infections, and carbapenem therapy were independent variables associated with increased readmissions due to poor infection control. Readmissions not related to poor infection control, adverse events, and catheter-related complications were similar in multidrug-resistant compared to non-multidrug-resistant bacterial infections. Home intravenous therapy, administered by patients or their caretakers using elastomeric infusion pumps, was safe and effective for the treatment of most multidrug-resistant bacterial infections.

  9. Structural and biochemical analyses of alanine racemase from the multidrug-resistant Clostridium difficile strain 630.

    PubMed

    Asojo, Oluwatoyin A; Nelson, Sarah K; Mootien, Sara; Lee, Yashang; Rezende, Wanderson C; Hyman, Daniel A; Matsumoto, Monica M; Reiling, Scott; Kelleher, Alan; Ledizet, Michel; Koski, Raymond A; Anthony, Karen G

    2014-07-01

    Clostridium difficile, a Gram-positive, spore-forming anaerobic bacterium, is the leading cause of infectious diarrhea among hospitalized patients. C. difficile is frequently associated with antibiotic treatment, and causes diseases ranging from antibiotic-associated diarrhea to life-threatening pseudomembranous colitis. The severity of C. difficile infections is exacerbated by the emergence of hypervirulent and multidrug-resistant strains, which are difficult to treat and are often associated with increased mortality rates. Alanine racemase (Alr) is a pyridoxal-5'-phosphate (PLP)-dependent enzyme that catalyzes the reversible racemization of L- and D-alanine. Since D-alanine is an essential component of the bacterial cell-wall peptidoglycan, and there are no known Alr homologs in humans, this enzyme is being tested as an antibiotic target. Cycloserine is an antibiotic that inhibits Alr. In this study, the catalytic properties and crystal structures of recombinant Alr from the virulent and multidrug-resistant C. difficile strain 630 are presented. Three crystal structures of C. difficile Alr (CdAlr), corresponding to the complex with PLP, the complex with cycloserine and a K271T mutant form of the enzyme with bound PLP, are presented. The structures are prototypical Alr homodimers with two active sites in which the cofactor PLP and cycloserine are localized. Kinetic analyses reveal that the K271T mutant CdAlr has the highest catalytic constants reported to date for any Alr. Additional studies are needed to identify the basis for the high catalytic activity. The structural and activity data presented are first steps towards using CdAlr for the development of structure-based therapeutics for C. difficile infections.

  10. Structural elucidation and evaluation of multidrug-resistance modulatory capability of amarissinins A-C, diterpenes derived from Salvia amarissima.

    PubMed

    Bautista, Elihú; Fragoso-Serrano, Mabel; Ortiz-Pastrana, Naytzé; Toscano, Rubén A; Ortega, Alfredo

    2016-10-01

    Three new diterpenes (amarissinins A-C, 1-3) containing several oxygenated functionalities were isolated from the leaves and flowers of Salvia amarissima. The structures of these compounds were established through the analysis of their NMR spectroscopy and mass spectrometry data. The structures of compounds 1 and 2 were confirmed by single crystal X-ray diffraction. Compound 2 was identified as a C-10 epimer of dugesin F (5). The cytotoxic activity of these compounds against five human cancer cell lines was determined. Additionally, the capability to modulate the multidrug resistance (MDR) in the MCF-7 cancer cell line resistant to vinblastine was tested.

  11. Susceptibility of Multidrug-Resistant Gram-Negative Urine Isolates to Oral Antibiotics

    PubMed Central

    Zucchi, Paola C.; Chen, Alice; Raux, Brian R.; Kirby, James E.; McCoy, Christopher; Eliopoulos, George M.

    2016-01-01

    Increasing resistance among Gram-negative uropathogens limits treatment options, and susceptibility data for multidrug-resistant isolates are limited. We assessed the activity of five oral agents against 91 multidrug-resistant Gram-negative urine isolates that were collected from emergency department/hospitalized patients. Fosfomycin and nitrofurantoin were most active (>75% susceptibility). Susceptibilities to sulfamethoxazole-trimethoprim, ciprofloxacin, and ampicillin were ≤40%; empirical use of these agents likely provides inadequate coverage in areas with a high prevalence of multidrug-resistant uropathogens. PMID:26883704

  12. Modulation of Bacterial Multidrug Resistance Efflux Pumps of the Major Facilitator Superfamily

    PubMed Central

    Kumar, Sanath; Mukherjee, Mun Mun; Varela, Manuel F.

    2013-01-01

    Bacterial infections pose a serious public health concern, especially when an infectious disease has a multidrug resistant causative agent. Such multidrug resistant bacteria can compromise the clinical utility of major chemotherapeutic antimicrobial agents. Drug and multidrug resistant bacteria harbor several distinct molecular mechanisms for resistance. Bacterial antimicrobial agent efflux pumps represent a major mechanism of clinical resistance. The major facilitator superfamily (MFS) is one of the largest groups of solute transporters to date and includes a significant number of bacterial drug and multidrug efflux pumps. We review recent work on the modulation of multidrug efflux pumps, paying special attention to those transporters belonging primarily to the MFS. PMID:25750934

  13. Autophagy and Transporter-Based Multi-Drug Resistance

    PubMed Central

    Kumar, Priyank; Zhang, Dong-Mei; Degenhardt, Kurt; Chen, Zhe-Sheng

    2012-01-01

    All the therapeutic strategies for treating cancers aim at killing the cancer cells via apoptosis (programmed cell death type I). Defective apoptosis endow tumor cells with survival. The cell can respond to such defects with autophagy. Autophagy is a cellular process by which cytoplasmic material is either degraded to maintain homeostasis or recycled for energy and nutrients in starvation. A plethora of evidence has shown that the role of autophagy in tumors is complex. A lot of effort is needed to underline the functional status of autophagy in tumor progression and treatment, and elucidate how to tweak autophagy to treat cancer. Furthermore, during the treatment of cancer, the limitation for the cure rate and survival is the phenomenon of multi drug resistance (MDR). The development of MDR is an intricate process that could be regulated by drug transporters, enzymes, anti-apoptotic genes or DNA repair mechanisms. Reports have shown that autophagy has a dual role in MDR. Furthermore, it has been reported that activation of a death pathway may overcome MDR, thus pointing the importance of other death pathways to regulate tumor cell progression and growth. Therefore, in this review we will discuss the role of autophagy in MDR tumors and a possible link amongst these phenomena. PMID:24710490

  14. Development of multidrug resistance due to multiple factors including P-glycoprotein overexpression under K-selection after MYC and HRAS oncogene activation.

    PubMed

    Nakamura, Yukari; Sato, Hiroyuki; Motokura, Toru

    2006-05-15

    Multistep tumorigenesis is a form of microevolution consisting of mutation and selection. To clarify the role of selection modalities in tumor development, we examined two alternative evolutionary conditions, r-selection in sparse culture, which allows cells to proliferate rapidly, and K-selection in confluent culture, in which overcrowding constrains cell proliferation. Using MYC- and EJ-RAS-transformed rat embryo fibroblasts, we found that K-selected cells acquired and stably maintained multidrug resistance (MDR) to DOX, VCR, MTX and Ara-C. Then, we examined the involvement of a number of factors potentially causal of the development of MDR, that is, ploidy, Tp53 mutation, doubling time and the expression levels of genes related to drug resistance. Although ploidy status and Tp53 mutations did not correlate with MDR, we found that Abcb1/Mdr1, encoding P-glycoprotein (Pgp), was significantly upregulated after K-selection. Cyclosporin A, a competitive inhibitor of Pgp, increased the intracellular accumulation of DOX and reduced the resistance to it. Indeed, the population of Pgp-transfected cells significantly expanded under K-, but not under r-selection. In addition to Pgp upregulation, altered expression of other genes such as Cda/cytidine deaminase and Slc29a1/equilibrative nucleoside transporter 1 and prolonged doubling times were associated with MDR. This system reproduces events associated with MDR in vivo and would be useful for analysis of MDR development.

  15. Audiological Evaluation of Patients Taking Kanamycin for Multidrug Resistant Tuberculosis

    PubMed Central

    Sharma, Vishal; Bhagat, Sanjeev; Verma, Bhimsain; Singh, Ravinder; Singh, Surinderpal

    2016-01-01

    Introduction: The incidence of multidrug resistant tuberculosis is increasing in developing countries. Aminoglycosides are an integral part of second-line drugs, however ototoxicity is a major limitation for their use. This study aims to determine the extent of hearing loss in patients taking one of the commonly prescribed drugs for Multidrug resistant tuberculosis (MDR-TB), Kanamycin, at a Government Medical College, Patiala, Punjab, India, which is a 1200 bed tertiary care hospital. Materials and Methods: A total of 100 patients (68 males and 32 females) with confirmed diagnosis of MDR-TB were included in this study conducted between January 2012 and February 2014. Subjects were between 15 to 60 years of age, with a mean age of 37.46 ± 10.1. Pure tone audiometry (PTA) was performed before the start of the therapy, as a baseline, and was repeated after 1 week and 6 weeks of Kanamycin use to assess hearing loss as an effect of therapy. Results: Of the 100 patients examined, ototoxicity was found in 18 subjects post therapy. Incidence of high frequency hearing loss was 2% at week 1, and 12% after 6 weeks of follow up. However, 4% of the cases developed flat loss at week 6. The hearing loss was bilateral in 13 patients and unilateral in 5 patients. Ototoxicity was more common in males (66.67%) compared to females (33.3%). Maximum cases were found in the age group of 36 to 45 years (36.8%), the majority being from a rural background (83.3%). The association with socioeconomic status (P=0.024) and co-morbid conditions like diabetes and hypertension (P=0.001) reached statistical significance. Conclusion: Lack of specific guidelines to monitor patients taking aminoglycosides makes ototoxicity a major adverse effect of their use in MDR-TB. More studies are mandated to study the risk factors associated with the development of ototoxicity and for the development of alternate drugs for the treatment of MDR-TB. PMID:27429949

  16. Ontogeny, aging, and gender-related changes in hepatic multidrug resistant protein genes in rats.

    PubMed

    Zhu, Qiong-Ni; Hou, Wei-Yu; Xu, Shang-Fu; Lu, Yuan-Fu; Liu, Jie

    2017-02-01

    Multidrug resistance proteins (Mrps) are efflux transporters playing important roles in endogenous substances and xenobiotics transport out of the liver. Children, elderly, gender and physio-pathological conditions could influence their expression and result in changes in drug disposition.

  17. Multidrug resistance and ESBL-producing Salmonella spp. isolated from broiler processing plants.

    PubMed

    Ziech, Rosangela Estel; Lampugnani, Camila; Perin, Ana Paula; Sereno, Mallu Jagnow; Sfaciotte, Ricardo Antônio Pilegi; Viana, Cibeli; Soares, Vanessa Mendonça; Pinto, José Paes de Almeida Nogueira; Bersot, Luciano dos Santos

    2016-01-01

    The aim of this study was to investigate the occurrence of multidrug-resistant, extended spectrum beta-lactamase (ESBL) producing Salmonella spp. isolated from conveyor belts of broiler cutting rooms in Brazilian broiler processing plants. Ninety-eight strains of Salmonella spp. were analyzed. Multidrug resistance was determined by the disk diffusion test and the susceptibility of the isolated bacteria was evaluated against 18 antimicrobials from seven different classes. The double disk diffusion test was used to evaluate ESBL production. Of the 98 strains tested, 84 were multidrug resistant. The highest rates of resistance were against nalidixic acid (95%), tetracycline (91%), and the beta-lactams: ampicillin and cefachlor (45%), followed by streptomycin and gentamicin with 19% and 15% of strain resistance, respectively. By contrast, 97% of the strains were sensitive to chloramphenicol. 45% of the strains were positive for the presence of ESBL activity. In this study, high rates of multidrug resistance and ESBL production were observed in Salmonella spp.

  18. Outcomes of Multidrug-Resistant Tuberculosis among Binational Cases in El Paso, Texas

    PubMed Central

    Ferrer, Gustavo; Acuna-Villaorduna, Carlos; Escobedo, Miguel; Vlasich, Esteban; Rivera, Manuel

    2010-01-01

    In the United States, multidrug-resistant tuberculosis (MDR-TB) is more commonly seen among foreign-born patients. We report outcomes for 46 patients with MDR-TB who were born in Mexico and treated along the United States–Mexico border. According to our definition, 30 were cured, 3 showed treatment failure, 3 died, and 10 abandoned treatment. Multidrug-resistant tuberculosis can be successfully treated on an ambulatory basis. PMID:21036837

  19. Identification of New Drug Targets in Multi-Drug Resistant Bacterial Infections

    DTIC Science & Technology

    2014-10-01

    Identification of New Drug Targets in Multi-Drug Resistant Bacterial Infections PRINCIPAL INVESTIGATOR: Andrew M. Gulick, PhD...Identification of New Drug Targets in Multi-Drug Resistant Bacterial Infections 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-11-2-0218 5c... infections . Recently, community-acquired infections , infections in wounded U.S. service members, and infections in residents of long-term care facilities

  20. Nonfunctioning Juxtaglomerular Cell Tumor

    PubMed Central

    Sakata, Ryoko; Shimoyamada, Hiroaki; Yanagisawa, Masahiro; Murakami, Takayuki; Makiyama, Kazuhide; Nakaigawa, Noboru; Inayama, Yoshiaki; Ohashi, Kenichi; Nagashima, Yoji; Yao, Masahiro; Kubota, Yoshinobu

    2013-01-01

    The juxtaglomerular cell tumor (JGCT) is a rare renal tumor characterized by excessive renin secretion causing intractable hypertension and hypokalemia. However, asymptomatic nonfunctioning JGCT is extremely rare. Here, we report a case of nonfunctioning JGCT in a 31-year-old woman. The patient presented with a left renal tumor without hypertension or hypokalemia. Under a clinical diagnosis of renal cell carcinoma, radical nephrectomy was performed. The tumor was located in the middle portion adjacent to the renal pelvis, measuring 2 cm in size. Pathologically, the tumor was composed of cuboidal cells forming a solid arrangement, immunohistochemically positive for renin. Based on these findings, the tumor was diagnosed as JGCT. In cases with hyperreninism, preoperative diagnosis of JGCT is straightforward but difficult in nonfunctioning case. Generally, JGCT presents a benign biological behavior. Therefore, we should take nonfunctioning JGCT into the differential diagnoses for renal tumors, especially in younger patients to avoid excessive surgery. PMID:23607027

  1. Tumor cell metabolism

    PubMed Central

    Romero-Garcia, Susana; Lopez-Gonzalez, Jose Sullivan; B´ez-Viveros, José Luis; Aguilar-Cazares, Dolores

    2011-01-01

    Cancer is a genetic disease that is caused by mutations in oncogenes, tumor suppressor genes and stability genes. The fact that the metabolism of tumor cells is altered has been known for many years. However, the mechanisms and consequences of metabolic reprogramming have just begun to be understood. In this review, an integral view of tumor cell metabolism is presented, showing how metabolic pathways are reprogrammed to satisfy tumor cell proliferation and survival requirements. In tumor cells, glycolysis is strongly enhanced to fulfill the high ATP demands of these cells; glucose carbons are the main building blocks in fatty acid and nucleotide biosynthesis. Glutaminolysis is also increased to satisfy NADPH regeneration, whereas glutamine carbons replenish the Krebs cycle, which produces metabolites that are constantly used for macromolecular biosynthesis. A characteristic feature of the tumor microenvironment is acidosis, which results from the local increase in lactic acid production by tumor cells. This phenomenon is attributed to the carbons from glutamine and glucose, which are also used for lactic acid production. Lactic acidosis also directs the metabolic reprogramming of tumor cells and serves as an additional selective pressure. Finally, we also discuss the role of mitochondria in supporting tumor cell metabolism. PMID:22057267

  2. ▼Bedaquiline for multidrug-resistant tuberculosis.

    PubMed

    2014-11-01

    Resistance to drugs used to treat tuberculosis (TB) is a major public health problem that threatens progress made in TB management and control worldwide. It may result from improper use of antibiotics, including prescription of non-standard treatment regimens and poor adherence to drug therapy. Multidrug-resistant TB (MDR-TB) is defined as resistance to isoniazid and rifampicin, with or without resistance to other first-line drugs. Extensively drug-resistant TB (XDR-TB) refers to resistance to at least isoniazid and rifampicin, and to any fluoroquinolone, and to any of the three second-line injectables  (amikacin, capreomycin and kanamycin). In 2012, DTB discussed the investigation, management and treatment of patients with MDR- and XDR-TB. Earlier this year, ▼bedaquiline (Sirturo) and ▼delamanid (Deltyba) were authorised by the European Medicines Agency (EMA) under its 'conditional market authorisation' scheme for use as part of an appropriate combination regimen for pulmonary MDR-TB in adult patients "when an effective treatment regimen cannot otherwise be composed for reasons of resistance or tolerability." In this article, we review the evidence for bedaquiline in the management of MDR-TB.

  3. Endobronchial valve treatment of destructive multidrug-resistant tuberculosis

    PubMed Central

    Levin, A.; Felker, I.; Tceymach, E.; Krasnov, D.

    2016-01-01

    SUMMARY BACKGROUND: In accordance with the existing hypothesis, the application of an endobronchial valve (EbV) leads to selective curative atelectasis of the affected part of the lung, contributing to early closure of cavities. OBJECTIVE: To assess the effect of EbV treatment on the course of tuberculosis (TB). METHODS: We compared the efficacy of EbV treatment and complex second-line treatment in treating patients with destructive pulmonary multidrug-resistant TB (MDR-TB). Bacteriological conversion and closure of cavities were selected as criteria to assess the effectiveness of EbV application. A total of 102 patients with destructive MDR-TB were enrolled into the study and randomly divided into two groups: 49 patients had an EbV installed (intervention group) and 53 patients received complex second-line treatment (control group). Complex chemotherapy was administered to both groups throughout the study period. RESULTS: The cure rate in the short- and long-term follow-up periods in the intervention group was shown to be much higher, 95.9% by bacteriological conversion and 67.3% by cavity closure. On comparison with the control group, this was respectively 37.7% and 20.7% (P < 0.0001). CONCLUSIONS: The application of EbV treatment can significantly improve the effectiveness of second-line chemotherapy regimens in MDR-TB patients. PMID:27776598

  4. [Multidrug-resistant tuberculosis: challenges of a global emergence].

    PubMed

    Comolet, T

    2015-10-01

    Drug-resistant tuberculosis, in particular Multi-Drug Resistant (MDR-TB) is an increasing global concern and a major burden for some developing countries, especially the BRICS. It is assumed that every year roughly 350 000 new MDR-TB cases occur in the world, on average in 20.5% of TB patients that have been previously treated but also in 3.5% of persons that have never been on TB treatment before. The global distribution of cases is very heterogeneous and is now better understood thanks to a growing number of specific surveys and routine surveillance systems: incidence is much higher in southern Africa and in all countries formerly part of the USSR. Countries with weak health systems and previously inefficient TB control programs are highly vulnerable to MDR epidemics because program failures do help creating, maintaining and spreading resistances. Global response is slowly rolled out and diagnosis capacities are on the rise (mostly with genotypic methods) but adequate and successful treatment and care is still limited to a minority of global cases. From a public health perspective the MDR-TB growing epidemics will not be controlled merely by the introduction of few new antibiotics because it is also linked to patient's compliance and adequate case management supported by efficient TB program. In depth quality improvement will only be achieved after previous errors are thoroughly analyzed and boldly corrected.

  5. Multidrug resistant Enterobacteriaceae in New Zealand: a current perspective.

    PubMed

    Toombs-Ruane, L J; Benschop, J; Burgess, S; Priest, P; Murdoch, D R; French, N P

    2017-03-01

    In this article we review mechanisms and potential transmission pathways of multidrug resistance in Enterobacteriaceae, with an emphasis on extended-spectrum β-lactamase (ESBL)-production. This provides background to better understand challenges presented by this important group of antimicrobial resistant bacteria, and inform measures aimed at prevention and control of antimicrobial resistance in general. Humans and animals interact at various levels; household pets cohabit with humans, and other animals interact with people through direct contact, as well as through the food chain and the environment. These interactions offer opportunity for bacteria such as ESBL-producers to be shared and transmitted between species and, in turn, increase the risk of zoonotic and reverse-zoonotic disease transmission. A key step in curtailing antimicrobial resistance is improved stewardship of antimicrobials, including surveillance of their use, better infection-control and prevention, and a better understanding of prescribing practice in both veterinary and medical professions in New Zealand. This will also require prospective observational studies to examine risk factors for antimicrobial resistance. Due to the interconnectedness of humans, animals and the environment actions to effect the changes required should be undertaken using a One Health approach.

  6. Multidrug resistant citrobacter: an unusual cause of liver abscess.

    PubMed

    Kumar, Prabhat; Ghosh, Soumik; Rath, Deepak; Gadpayle, A K

    2013-04-22

    Liver abscesses are infectious, space occupying lesions in the liver, the two most common abscesses being pyogenic and amoebic. A pyogenic liver abscess (PLA) is a rare condition with a reported incidence of 20 per 100 000 hospital admissions in the western population. The right lobe of the liver is the most common site in both types of liver abscess. Clinical presentation is elusive with complaints of fever, right upper quadrant pain in the abdomen and hepatomegaly with or without jaundice. The aetiology of PLA has changed in the past few decades and may be of biliary, portal, arterial or traumatic origin, but many cases are still cryptogenic. The most common organisms causing PLA are Gram-negative aerobes, especially Escherichia coli and Klebsiella pneumoniae. Studies have shown a high degree of antimicrobial susceptibility of isolated organism resulting in an overall lower mortality in PLA. Here, we present a case of PLA caused by multidrug-resistant Citrobacter freundii, which is an unusual organism to be isolated.

  7. Emerging cephalosporin and multidrug-resistant gonorrhoea in Europe.

    PubMed

    Cole, M J; Spiteri, G; Chisholm, S A; Hoffmann, S; Ison, C A; Unemo, M; Van de Laar, M

    2014-11-13

    Neisseria gonorrhoeae has consistently developed resistance to antimicrobials used therapeutically for gonorrhoea and few antimicrobials remain for effective empiric first-line therapy. Since 2009 the European gonococcal antimicrobial surveillance programme (Euro-GASP) has been running as a sentinel surveillance system across Member States of the European Union (EU) and European Economic Area (EEA) to monitor antimicrobial susceptibility in N. gonorrhoeae. During 2011, N. gonorrhoeae isolates were collected from 21 participating countries, and 7.6% and 0.5% of the examined gonococcal isolates had in vitro resistance to cefixime and ceftriaxone, respectively. The rate of ciprofloxacin and azithromycin resistance was 48.7% and 5.3%, respectively. Two (0.1%) isolates displayed high-level resistance to azithromycin, i.e. a minimum inhibitory concentration (MIC) ≥256 mg/L. The current report further highlights the public health need to implement the European response plan, including further strengthening of Euro-GASP, to control and manage the threat of multidrug resistant N. gonorrhoeae.

  8. What's new in multidrug-resistant pathogens in the ICU?

    PubMed

    Zilahi, Gabor; Artigas, Antonio; Martin-Loeches, Ignacio

    2016-12-01

    Over the last several decades, antibacterial drug use has become widespread with their misuse being an ever-increasing phenomenon. Consequently, antibacterial drugs have become less effective or even ineffective, resulting in a global health security emergency. The prevalence of multidrug-resistant organisms (MDROs) varies widely among regions and countries. The primary aim of antibiotic stewardship programs is to supervise the three most influential factors contributing to the development and transmission of MDROs, namely: (1) appropriate antibiotic prescribing; (2) early detection and prevention of cross-colonization of MDROs; and (3) elimination of reservoirs. In the future, it is expected that a number of countries will experience a rise in MDROs. These infections will be associated with a high consumption of healthcare resources manifested by a prolonged hospital stay and high mortality. As a counteractive strategy, minimization of broad-spectrum antibiotic use and prompt antibiotic administration will aid in reduction of antibiotic resistance. Innovative management approaches include development and implementation of rapid diagnostic tests that will help in both shortening the duration of therapy and allowing early targeted therapy. The institution of more accessible therapeutic drug monitoring will help to optimize drug administration and support a patient-specific approach. Areas where further research is required are investigation into the heterogeneity of critically ill patients and the need for new antibacterial drug development.

  9. [Multidrug-resistant tuberculosis: epidemiology and risk factors].

    PubMed

    Smaoui Fourati, S; Mzid, H; Marouane, C; Kammoun, S; Messadi-Akrout, F

    2015-08-01

    Despite the availability of potent drugs and the availability of vaccine, tuberculosis remains until today one of the most worrying infectious diseases because of both its morbidity and mortality. This serious health problem is further complicated by the emergence of multidrug-resistant (MDR) or extensively drug-resistant strains (XDR). The number of MDR and XDR strains has continued to increase in recent years. Therefore, it is necessary to determine the risk factors leading to the emergence of MDR-TB strains to improve its overall management. Most studies indicate that the irregular previous treatment of tuberculosis with poor adherence is the main risk factor found. Other risk factors such as digestive issues, age, sex, and immunosuppression have been reported by several studies. In Tunisia, MDR-TB prevalence remains low with 0.8% among new cases and 12% among the restatements but control of this disease is necessary and remains essentially preventive. It is based on real preventive strategies planned according to local and updated regional data.

  10. Multidrug-resistant tuberculosis: epidemiology, risk factors and case finding.

    PubMed

    Caminero, J A

    2010-04-01

    Although the multidrug-resistant tuberculosis (MDR-TB) epidemic is a very recent problem, many studies have attempted to understand it. We now have good estimates of the current burden (approximately 500 000 MDR-TB cases worldwide), and following the introduction of potential MDR-TB control strategies projections of these figures are being estimated. The projected trends in tuberculosis (TB) and MDR-TB incidence vary. Risk factors for resistance can be divided into two categories: 1) those facilitating the selection of resistance in the community and 2) the specific conditions that appear to increase some patients' vulnerability to resistance. The epidemiological situation varies greatly across countries, principally due to poor treatment practices and poor implementation of control programmes in the past-and even today, to a lesser degree-and recent data have suggested that national TB programmes that use existing drugs efficiently can postpone and even reverse the MDR-TB epidemic. Other factors that have also contributed to this epidemic situation are analysed in this article. The recognition of factors leading to the epidemic in some regions and the identification of populations at risk will assist in focusing case-finding efforts. From an individual perspective, treatment failures with first-line rifampicin-containing regimens and contacts of MDR-TB cases have the highest rates of resistance. Patients previously treated for TB and the other risk factors analysed in this article should be prioritised in case finding.

  11. Clinical management of infections caused by multidrug-resistant Enterobacteriaceae

    PubMed Central

    Delgado-Valverde, Mercedes; Sojo-Dorado, Jesús; Pascual, Álvaro

    2013-01-01

    Enterobacteriaceae showing resistance to cephalosporins due to extended-spectrum β-lactamases (ESBLs) or plasmid-mediated AmpC enzymes, and those producing carbapenemases have spread worldwide during the last decades. Many of these isolates are also resistant to other first-line agents such as fluoroquinolones or aminoglycosides, leaving few available options for therapy. Thus, older drugs such as colistin and fosfomycin are being increasingly used. Infections caused by these bacteria are associated with increased morbidity and mortality compared with those caused by their susceptible counterparts. Most of the evidence supporting the present recommendations is from in vitro data, animal studies, and observational studies. While carbapenems are considered the drugs of choice for ESBL and AmpC producers, recent data suggest that certain alternatives may be suitable for some types of infections. Combined therapy seems superior to monotherapy in the treatment of invasive infections caused by carbapenemase-producing Enterobacteriaceae. Optimization of dosage according to pharmacokinetics/pharmacodynamics data is important for the treatment of infections caused by isolates with borderline minimum inhibitory concentration due to low-level resistance mechanisms. The increasing frequency and the rapid spread of multidrug resistance among the Enterobacteriaceae is a true and complex public health problem. PMID:25165544

  12. Multidrug-Resistant Acinetobacter spp.: Increasingly Problematic Nosocomial Pathogens

    PubMed Central

    Lee, Kyungwon; Yong, Dongeun; Jeong, Seok Hoon

    2011-01-01

    Pathogenic bacteria have increasingly been resisting to antimicrobial therapy. Recently, resistance problem has been relatively much worsened in Gram-negative bacilli. Acinetobacter spp. are typical nosocomial pathogens causing infections and high mortality, almost exclusively in compromised hospital patients. Acinetobacter spp. are intrinsically less susceptible to antibiotics than Enterobacteriaceae, and have propensity to acquire resistance. A surveillance study in Korea in 2009 showed that resistance rates of Acinetobacter spp. were very high: to fluoroquinolone 67%, to amikacin 48%, to ceftazidime 66% and to imipenem 51%. Carbapenem resistance was mostly due to OXA type carbapenemase production in A. baumannii isolates, whereas it was due to metallo-β-lactamase production in non-baumannii Acinetobacter isolates. Colistin-resistant isolates were rare but started to be isolated in Korea. Currently, the infection caused by multidrug-resistant A. baumannii is among the most difficult ones to treat. Analysis at tertiary care hospital in 2010 showed that among the 1,085 isolates of Acinetobacter spp., 14.9% and 41.8% were resistant to seven, and to all eight antimicrobial agents tested, respectively. It is known to be difficult to prevent Acinetobacter spp. infection in hospitalized patients, because the organisms are ubiquitous in hospital environment. Efforts to control resistant bacteria in Korea by hospitals, relevant scientific societies and government agencies have only partially been successful. We need concerted multidisciplinary efforts to preserve the efficacy of currently available antimicrobial agents, by following the principles of antimicrobial stewardship. PMID:22028150

  13. Common errors in multidrug-resistant tuberculosis management.

    PubMed

    Monedero, Ignacio; Caminero, Jose A

    2014-02-01

    Multidrug-resistant tuberculosis (MDR-TB), defined as being resistant to at least rifampicin and isoniazid, has an increasing burden and threatens TB control. Diagnosis is limited and usually delayed while treatment is long lasting, toxic and poorly effective. MDR-TB management in scarce-resource settings is demanding however it is feasible and extremely necessary. In these settings, cure rates do not usually exceed 60-70% and MDR-TB management is novel for many TB programs. In this challenging scenario, both clinical and programmatic errors are likely to occur. The majority of these errors may be prevented or alleviated with appropriate and timely training in addition to uninterrupted procurement of high-quality drugs, updated national guidelines and laws and an overall improvement in management capacities. While new tools for diagnosis and shorter and less toxic treatment are not available in developing countries, MDR-TB management will remain complex in scarce resource settings. Focusing special attention on the common errors in diagnosis, regimen design and especially treatment delivery may benefit patients and programs with current outdated tools. The present article is a compilation of typical errors repeatedly observed by the authors in a wide range of countries during technical assistant missions and trainings.

  14. Effects of mefloquine use on Plasmodium vivax multidrug resistance.

    PubMed

    Khim, Nimol; Andrianaranjaka, Voahangy; Popovici, Jean; Kim, Saorin; Ratsimbasoa, Arsene; Benedet, Christophe; Barnadas, Celine; Durand, Remy; Thellier, Marc; Legrand, Eric; Musset, Lise; Menegon, Michela; Severini, Carlo; Nour, Bakri Y M; Tichit, Magali; Bouchier, Christiane; Mercereau-Puijalon, Odile; Ménard, Didier

    2014-10-01

    Numerous studies have indicated a strong association between amplification of the multidrug resistance-1 gene and in vivo and in vitro mefloquine resistance of Plasmodium falciparum. Although falciparum infection usually is not treated with mefloquine, incorrect diagnosis, high frequency of undetected mixed infections, or relapses of P. vivax infection triggered by P. falciparum infections expose non-P. falciparum parasites to mefloquine. To assess the consequences of such unintentional treatments on P. vivax, we studied variations in number of Pvmdr-1 (PlasmoDB accession no. PVX_080100, NCBI reference sequence NC_009915.1) copies worldwide in 607 samples collected in areas with different histories of mefloquine use from residents and from travelers returning to France. Number of Pvmdr-1 copies correlated with drug use history. Treatment against P. falciparum exerts substantial collateral pressure against sympatric P. vivax, jeopardizing future use of mefloquine against P. vivax. A drug policy is needed that takes into consideration all co-endemic species of malaria parasites.

  15. Genetic Drivers of Multidrug Resistance in Candida glabrata

    PubMed Central

    Healey, Kelley R.; Jimenez Ortigosa, Cristina; Shor, Erika; Perlin, David S.

    2016-01-01

    Both the incidence of invasive fungal infections and rates of multidrug resistance associated with fungal pathogen Candida glabrata have increased in recent years. In this perspective, we will discuss the mechanisms underlying the capacity of C. glabrata to rapidly develop resistance to multiple drug classes, including triazoles and echinocandins. We will focus on the extensive genetic diversity among clinical isolates of C. glabrata, which likely enables this yeast to survive multiple stressors, such as immune pressure and antifungal exposure. In particular, over half of C. glabrata clinical strains collected from U.S. and non-U.S. sites have mutations in the DNA mismatch repair gene MSH2, leading to a mutator phenotype and increased frequencies of drug-resistant mutants in vitro. Furthermore, recent studies and data presented here document extensive chromosomal rearrangements among C. glabrata strains, resulting in a large number of distinct karyotypes within a single species. By analyzing clonal, serial isolates derived from individual patients treated with antifungal drugs, we were able to document chromosomal changes occurring in C. glabrata in vivo during the course of antifungal treatment. Interestingly, we also show that both MSH2 genotypes and chromosomal patterns cluster consistently into specific strain types, indicating that C. glabrata has a complex population structure where genomic variants arise, perhaps during the process of adaptation to environmental changes, and persist over time. PMID:28018323

  16. Imidazopurinones are markers of physiological genomic damage linked to DNA instability and glyoxalase 1-associated tumour multidrug resistance.

    PubMed

    Thornalley, Paul J; Waris, Sahar; Fleming, Thomas; Santarius, Thomas; Larkin, Sarah J; Winklhofer-Roob, Brigitte M; Stratton, Michael R; Rabbani, Naila

    2010-09-01

    Glyoxal and methylglyoxal are reactive dicarbonyl metabolites formed and metabolized in physiological systems. Increased exposure to these dicarbonyls is linked to mutagenesis and cytotoxicity and enhanced dicarbonyl metabolism by overexpression of glyoxalase 1 is linked to tumour multidrug resistance in cancer chemotherapy. We report herein that glycation of DNA by glyoxal and methylglyoxal produces a quantitatively important class of nucleotide adduct in physiological systems-imidazopurinones. The adduct derived from methylglyoxal-3-(2'-deoxyribosyl)-6,7-dihydro-6,7-dihydroxy-6/7-methylimidazo-[2,3-b]purine-9(8)one isomers-was the major quantitative adduct detected in mononuclear leukocytes in vivo and tumour cell lines in vitro. It was linked to frequency of DNA strand breaks and increased markedly during apoptosis induced by a cell permeable glyoxalase 1 inhibitor. Unexpectedly, the DNA content of methylglyoxal-derived imidazopurinone and oxidative marker 7,8-dihydro-8-oxo-2'-deoxyguanosine were increased moderately in glyoxalase 1-linked multidrug resistant tumour cell lines. Together these findings suggest that imidazopurinones are a major type of endogenous DNA damage and glyoxalase 1 overexpression in tumour cells strives to counter increased imidazopurinone formation in tumour cells likely linked to their high glycolytic activity.

  17. Two genetically-related multidrug-resistant Mycobacterium tuberculosis strains induce divergent outcomes of infection in two human macrophage models.

    PubMed

    Yokobori, Noemí; López, Beatriz; Geffner, Laura; Sabio y García, Carmen; Schierloh, Pablo; Barrera, Lucía; de la Barrera, Silvia; Sakai, Shunsuke; Kawamura, Ikuo; Mitsuyama, Masao; Ritacco, Viviana; Sasiain, María del Carmen

    2013-06-01

    Mycobacterium tuberculosis has a considerable degree of genetic variability resulting in different epidemiology and disease outcomes. We evaluated the pathogen-host cell interaction of two genetically closely-related multidrug-resistant M. tuberculosis strains of the Haarlem family, namely the strain M, responsible for an extensive multidrug-resistant tuberculosis outbreak, and its kin strain 410 which caused a single case in two decades. Intracellular growth and cytokine responses were evaluated in human monocyte-derived macrophages and dU937 macrophage-like cells. In monocyte-derived macrophages, strain M grew more slowly and induced lower levels of TNF-α and IL-10 than 410, contrasting with previous studies with other strains, where a direct correlation was observed between increased intracellular growth and epidemiological success. On the other hand, in dU937 cells, no difference in growth was observed between both strains, and strain M induced significantly higher TNF-α levels than strain 410. We found that both cell models differed critically in the expression of receptors for M. tuberculosis entry, which might explain the different infection outcomes. Our results in monocyte-derived macrophages suggest that strain M relies on a modest replication rate and cytokine induction, keeping a state of quiescence and remaining rather unnoticed by the host. Collectively, our results underscore the impact of M. tuberculosis intra-species variations on the outcome of host cell infection and show that results can differ depending on the in vitro infection model.

  18. Multidrug-Resistant Organism Infections in Patients with Left Ventricular Assist Devices.

    PubMed

    Donahey, Elisabeth E; Polly, Derek M; Vega, J David; Lyon, Marshall; Butler, Javed; Nguyen, Duc; Pekarek, Ann; Wittersheim, Kristin; Kilgo, Patrick; Paciullo, Christopher A

    2015-12-01

    Left ventricular assist devices improve survival prospects in patients with end-stage heart failure; however, infection complicates up to 59% of implantation cases. How many of these infections are caused by multidrug-resistant organisms is unknown. We sought to identify the incidence, risk factors, and outcomes of multidrug-resistant organism infection in patients who have left ventricular assist devices. We retrospectively evaluated the incidence of multidrug-resistant organisms and the independent risk factors associated with them in 57 patients who had permanent left ventricular assist devices implanted at our institution from May 2007 through October 2011. Outcomes included death, transplantation, device explantation, number of subsequent hospital admissions, and number of subsequent admissions related to infection. Infections were categorized in accordance with criteria from the Infectious Diseases Council of the International Society for Heart and Lung Transplantation. Multidrug-resistant organism infections developed in 18 of 57 patients (31.6%)-a high incidence. We found 3 independent risk factors: therapeutic goal (destination therapy vs bridging), P=0.01; body mass index, P=0.04; and exposed velour at driveline exit sites, P=0.004. We found no significant differences in mortality, transplantation, or device explantation rates; however, there was a statistically significant increase in postimplantation hospital admissions in patients with multidrug-resistant organism infection. To our knowledge, this is the first report in the medical literature concerning multidrug-resistant organism infection in patients who have permanent left ventricular assist devices.

  19. Efflux pump gene hefA of Helicobacter pylori plays an important role in multidrug resistance

    PubMed Central

    Liu, Zhi-Qiang; Zheng, Peng-Yuan; Yang, Ping-Chang

    2008-01-01

    AIM: To determine whether efflux systems contribute to multidrug resistance of H pylori. METHODS: A chloramphenicol-induced multidrug resistance model of six susceptible H pylori strains (5 isolates and H pylori NCTC11637) was developed. Multidrug-resistant (MDR) strains were selected and the minimal inhibitory concentration (MIC) of erythromycin, metronidazole, penicillin G, tetracycline, and ciprofloxacin in multidrug resistant strains and their parent strains was determined by agar dilution tests. The level of mRNA expression of hefA was assessed by fluorescence real-time quantitative PCR. A H pylori LZ1026 knockout mutant (ΔH pylori LZ1026) for (putative) efflux protein was constructed by inserting the kanamycin resistance cassette from pEGFP-N2 into hefA, and its susceptibility profiles to 10 antibiotics were evaluated. RESULTS: The MIC of six multidrug-resistant strains (including 5 clinical isolates and H pylori NCTC11637) increased significantly (≥ 4-fold) compared with their parent strains. The expression level of hefA gene was significantly higher in the MDR strains than in their parent strains (P = 0.033). A H pylori LZ1026 mutant was successfully constructed and the ΔH pylori LZ1026 was more susceptible to four of the 10 antibiotics. All the 20 strains displayed transcripts for hefA that confirmed the in vitro expression of these genes. CONCLUSION: The efflux pump gene hefA plays an important role in multidrug resistance of H pylori. PMID:18777600

  20. Reversal of P-gp-mediated multidrug resistance in colon cancer by cinobufagin.

    PubMed

    Yuan, Zeting; Shi, Xiaojing; Qiu, Yanyan; Jia, Tingting; Yuan, Xia; Zou, Yu; Liu, Cheng; Yu, Hui; Yuan, Yuxia; He, Xue; Xu, Ke; Yin, Peihao

    2017-03-01

    Cinobufagin (CBF) is isolated from the skin and posterior auricular glands of the Asiatic toad (Bufo gargarizans). This study investigated the reversal effect of CBF on P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) in colon cancer. The effect of CBF on the cytotoxicity of anticancer drugs in P-gp overexpressing LoVo/ADR, HCT116/L, Cao-2/ADR cells and their parental cells was determined using CCK-8 assay. Apoptosis of anti-cancer drugs and accumulation of doxorubicin (DOX) and Rhodamine 123 (Rho123) in P-gp overexpressing cells were evaluated by flow cytometry. Results indicated that CBF significantly enhanced the sensitivity of P-gp substrate drugs on P-gp overexpressing cells, but had no effect on their parental cells. CBF enhanced the effect of DOX against P-gp-overexpressing LoVo/ADR cell xenografts in nude mice. Moreover, CBF also increased cell apoptosis of chemotherapy agents and intracellular accumulation of DOX and Rho123 in the MDR cells. Further research on the mechanisms revealed non-competitive inhibition of P-gp ATPase activity, but without altering the expression of P-gp. These findings demonstrated that CBF could be further developed into a safe and potent P-gp modulator for combination use with anticancer drugs in cancer chemotherapy.

  1. [Retroperitoneal germ cell tumor].

    PubMed

    Borrell Palanca, A; García Garzón, J; Villamón Fort, R; Domenech Pérez, C; Martínez Lorente, A; Gunthner, S; García Sisamón, F

    1999-03-01

    We report a case of retroperitoneal extragonadal germ-cell tumor in an 17 years old patient who presented with aedema and pain in left inferior extremity asociated with hemopthysis caused by pulmonar metastasis, who was treated with chemotherapy and resection of residual mass and pulmonary nodes. Dyagnosis was stableshed by fine neadle aspiration biopsy of the wass. We comment on the difficult of stableshing differential dyagnosis between retroperitoneal extragonadal germ-cell tumor and metastasis of a testicular tumor. Dyagnosis is stableshed by the finding of a histologically malignant germ-cell tumor with normal testis. We considered physical examination and ecographyc exploration enough for a correct dyagnosis.

  2. Evaluation of multidrug resistant phenotype by flow cytometry with monoclonal antibodies and functional tests.

    PubMed

    Lizard, G; Maynadié, M; Roignot, P; Lizard-Nacol, S; Poupon, M F

    1995-03-01

    Multidrug resistant (MDR) phenotype is characterized by a defect in drug accumulation caused by overexpression of a transmembrane glycoprotein, the P-glycoprotein (P-gp). MDR phenotype can be characterized either with monoclonal antibodies raised against P-gp or with functional tests, most often based on the incorporation of fluorescent compounds. In the present study, data obtained with the monoclonal antibodies C219, JSB1 and MRK16 are compared to those of functional tests performed by flow cytometry including uptake of daunorubicin (DNR), Rhodamine 123 (Rh 123) or Hoechst 33342. Sensitive and resistant cell lines K562S, K562R, KBA1 and KB31, derived either from a human chronic myeloid leukemia or from a human epithelial carcinoma, were used. In resistant cells, P-gp expression was revealed with either the monoclonal antibodies C219, JSB1 or MRK-16. The most specific results were obtained with MRK-16. With functional tests, no matter which dyes were used, the fluorescence was always stronger in sensitive than in resistant cells. However, with DNR and Hoechst 33342, an incorporation of these dyes was exhibited in resistant cells. This phenomenon was not observed with Rh 123, which makes it possible to distinguish clearly between sensitive and resistant cells and to detect as few as 1% of resistant cells. Because of its high sensitivity, the functional test involving incorporation of Rh 123 was successfully used in acute myeloid leukemia to detect multichemoresistant cells.

  3. Identification of Tumor Endothelial Cells with High Aldehyde Dehydrogenase Activity and a Highly Angiogenic Phenotype

    PubMed Central

    Maishi, Nako; Ohga, Noritaka; Hida, Yasuhiro; Kawamoto, Taisuke; Iida, Junichiro; Shindoh, Masanobu; Tsuchiya, Kunihiko; Shinohara, Nobuo; Hida, Kyoko

    2014-01-01

    Tumor blood vessels play an important role in tumor progression and metastasis. It has been reported that tumor endothelial cells (TECs) exhibit highly angiogenic phenotypes compared with those of normal endothelial cells (NECs). TECs show higher proliferative and migratory abilities than those NECs, together with upregulation of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2). Furthermore, compared with NECs, stem cell markers such as Sca-1, CD90, and multidrug resistance 1 are upregulated in TECs, suggesting that stem-like cells exist in tumor blood vessels. In this study, to reveal the biological role of stem-like TECs, we analyzed expression of the stem cell marker aldehyde dehydrogenase (ALDH) in TECs and characterized ALDHhigh TECs. TECs and NECs were isolated from melanoma-xenografted nude mice and normal dermis, respectively. ALDH mRNA expression and activity were higher in TECs than those in NECs. Next, ALDHhigh/low TECs were isolated by fluorescence-activated cell sorting to compare their characteristics. Compared with ALDHlow TECs, ALDHhigh TECs formed more tubes on Matrigel-coated plates and sustained the tubular networks longer. Furthermore, VEGFR2 expression was higher in ALDHhigh TECs than that in ALDHlow TECs. In addition, ALDH was expressed in the tumor blood vessels of in vivo mouse models of melanoma and oral carcinoma, but not in normal blood vessels. These findings indicate that ALDHhigh TECs exhibit an angiogenic phenotype. Stem-like TECs may have an essential role in tumor angiogenesis. PMID:25437864

  4. Leydig cell tumor

    MedlinePlus

    ... the cells in the testicles that release the male hormone, testosterone . ... seem to be linked to undescended testes . Leydig cell tumors make up a very small number of all testicular tumors. They are most often found in men between 30 and 60 years of age. This ...

  5. IND2, a pyrimido[1”,2”:1,5]pyrazolo[3,4-b]quinoline derivative, circumvents multi-drug resistance and causes apoptosis in colon cancer cells

    PubMed Central

    Karthikeyan, Chandrabose; Lee, Crystal; Moore, Joshua; Mittal, Roopali; Suswam, Esther A.; Abbott, Kodye L; Pondugula, Satyanarayana R.; Manne, Upender; Narayanan, Narayanan K.; Trivedi, Piyush; Tiwari, Amit K.

    2014-01-01

    Naturally occurring condensed quinolines have anticancer properties. In efforts to find active analogues, we designed and synthesized eight polycyclic heterocycles with a pyrimido[1”,2”:1,5]pyrazolo[3,4-b]quinoline framework (IND series). The compounds were evaluated for activity against colon (HCT-116 and S1-MI-80), prostate (PC3 and DU-145), breast (MCF-7 and MDAMB-231), ovarian (ov2008 and A2780), and hepatocellular (HepG2) cancer cells and against non-cancerous Madin Darby canine kidney (MDCK), mouse embryonic fibroblast (NIH/3T3), and human embryonic kidney cells (HEK293). IND-2, a 4-chloro-2-methyl pyrimido[1”,2”:1,5]pyrazolo[3,4-b]quinoline, exhibited more than tenfold selectivity and potent cytotoxic activity against colon cancer cells relative to the other cancer and non-cancer cells. With five additional colon cancer cell lines (HT-29, HCT-15, LS-180, LS-174, and LoVo), IND-2 had similar cytotoxicity and selectivity, and submicromolar concentrations caused changes in the morphology of HCT-116 and HCT-15 cells. IND-2 did not activate the transactivating function of the pregnane X receptor (PXR), indicating that it does not induce PXR-regulated ABCB1 or ABCG2 transporters. Indeed, IND-2 was not a substrate of ABCB1 or ABCG2, and it induced cytotoxicity in HEK293 cells overexpressing ABCB1 or ABCG2 to the same extent as in normal HEK293 cells. IND-2 was cytotoxic to resistant colon carcinoma S1-MI-80 cells, approximately three- and fivefold more than SN-38 and topotecan, respectively. In HCT-116 colon cancer cells, IND-2 produced concentration-dependent changes in mitochondrial membrane potential, leading to apoptosis, and sub-micromolar concentrations caused chromosomal DNA fragmentation. These findings suggest that, by increasing apoptosis, IND-2 has potential therapeutic efficacy for colorectal cancer. PMID:25537531

  6. IND-2, a pyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinoline derivative, circumvents multi-drug resistance and causes apoptosis in colon cancer cells.

    PubMed

    Karthikeyan, Chandrabose; Lee, Crystal; Moore, Joshua; Mittal, Roopali; Suswam, Esther A; Abbott, Kodye L; Pondugula, Satyanarayana R; Manne, Upender; Narayanan, Narayanan K; Trivedi, Piyush; Tiwari, Amit K

    2015-02-01

    Naturally occurring condensed quinolines have anticancer properties. In efforts to find active analogues, we designed and synthesized eight polycyclic heterocycles with a pyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinoline framework (IND series). The compounds were evaluated for activity against colon (HCT-116 and S1-MI-80), prostate (PC3 and DU-145), breast (MCF-7 and MDAMB-231), ovarian (ov2008 and A2780), and hepatocellular (HepG2) cancer cells and against non-cancerous Madin Darby canine kidney (MDCK), mouse embryonic fibroblast (NIH/3T3), and human embryonic kidney cells (HEK293). IND-2, a 4-chloro-2-methyl pyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinoline, exhibited more than ten-fold selectivity and potent cytotoxic activity against colon cancer cells relative to the other cancer and non-cancer cells. With five additional colon cancer cell lines (HT-29, HCT-15, LS-180, LS-174, and LoVo), IND-2 had similar cytotoxicity and selectivity, and sub-micromolar concentrations caused changes in the morphology of HCT-116 and HCT-15 cells. IND-2 did not activate the transactivating function of the pregnane X receptor (PXR), indicating that it does not induce PXR-regulated ABCB1 or ABCG2 transporters. Indeed, IND-2 was not a substrate of ABCB1 or ABCG2, and it induced cytotoxicity in HEK293 cells overexpressing ABCB1 or ABCG2 to the same extent as in normal HEK293 cells. IND-2 was cytotoxic to resistant colon carcinoma S1-MI-80 cells, approximately three- and five-fold more than SN-38 and topotecan, respectively. In HCT-116 colon cancer cells, IND-2 produced concentration-dependent changes in mitochondrial membrane potential, leading to apoptosis, and sub-micromolar concentrations caused chromosomal DNA fragmentation. These findings suggest that, by increasing apoptosis, IND-2 has potential therapeutic efficacy for colorectal cancer.

  7. Merkel cell tumor.

    PubMed

    Kitazawa, M; Watanabe, H; Kobayashi, H; Ohnishi, Y; Shitara, A; Nitto, H

    1987-06-01

    A Merkel cell tumor appeared on the left cheek of an 83-year-old female was reported. The tumor was located mainly in the dermis and infiltrated to the subcutaneous adipose tissue with an involvement of the blood vessels and lymphatics at the periphery. Electron-microscopically, few of the dense-cored granules and the single globular aggregates of intermediate filaments at the nuclear indentations were observed. Electron-microscopic uranaffin reaction proved positive reaction on the dense-cored granules. Half of the cytoplasmic border was smooth, while the rest had short projections. Desmosomes or junctional complexes were not detected among the tumor cells. Immunohistochemically, the cytoplasm of tumor cell showed positive reaction to both neuron-specific enolase (NSE) and keratin. The single globular positive spots of the latter were localized in accordance with the aggregates of intermediate filaments. These findings suggested a neurogenic origin with double differentiation, epithelial and neuroendocrine, of the Merkel cell tumor.

  8. Human multidrug-resistant Mycobacterium bovis infection in Mexico.

    PubMed

    Vazquez-Chacon, Carlos A; Martínez-Guarneros, Armando; Couvin, David; González-Y-Merchand, Jorge A; Rivera-Gutierrez, Sandra; Escobar-Gutierrez, Alejandro; De-la-Cruz López, Juan J; Gomez-Bustamante, Adriana; Gonzalez-Macal, Gabriela A; Gonçalves Rossi, Livia Maria; Muñiz-Salazar, Raquel; Rastogi, Nalin; Vaughan, Gilberto

    2015-12-01

    Here, we describe the molecular characterization of six human Mycobacterium bovis clinical isolates, including three multidrug resistant (MDR) strains, collected in Mexico through the National Survey on Tuberculosis Drug Resistance (ENTB-2008), a nationally representative survey conducted during 2008-2009 in nine states with a stratified cluster sampling design. The genetic background of bovine M. bovis strains identified in three different states of Mexico was studied in parallel to assess molecular relatedness of bovine and human strains. Additionally, resistance to first and second line anti-tuberculosis (TB) drugs and molecular identification of mutations conferring drug resistance was also performed. All strains were characterized by spoligotyping and 24-loci MIRU-VNTRs, and analyzed using the SITVIT2 (n = 112,000 strains) and SITVITBovis (n = 25,000 strains) proprietary databases of Institut Pasteur de la Guadeloupe. Furthermore, data from this study (n = 55 isolates), were also compared with genotypes recorded for M. bovis from USA (n = 203), Argentina (n = 726), as well as other isolates from Mexico (independent from the present study; n = 147), to determine any evidence for genetic relatedness between circulating M. bovis strains. The results showed that all human M. bovis cases were not genetically related between them or to any bovine strain. Interestingly, a high degree of genetic variability was observed among bovine strains. Several autochthonous and presumably imported strains were identified. The emergence of drug-resistant M. bovis is an important public health problem that jeopardizes the success of TB control programs in the region.

  9. A multifaceted analysis of HIV-1 protease multidrug resistance phenotypes

    PubMed Central

    2011-01-01

    Background Great strides have been made in the effective treatment of HIV-1 with the development of second-generation protease inhibitors (PIs) that are effective against historically multi-PI-resistant HIV-1 variants. Nevertheless, mutation patterns that confer decreasing susceptibility to available PIs continue to arise within the population. Understanding the phenotypic and genotypic patterns responsible for multi-PI resistance is necessary for developing PIs that are active against clinically-relevant PI-resistant HIV-1 variants. Results In this work, we use globally optimal integer programming-based clustering techniques to elucidate multi-PI phenotypic resistance patterns using a data set of 398 HIV-1 protease sequences that have each been phenotyped for susceptibility toward the nine clinically-approved HIV-1 PIs. We validate the information content of the clusters by evaluating their ability to predict the level of decreased susceptibility to each of the available PIs using a cross validation procedure. We demonstrate the finding that as a result of phenotypic cross resistance, the considered clinical HIV-1 protease isolates are confined to ~6% or less of the clinically-relevant phenotypic space. Clustering and feature selection methods are used to find representative sequences and mutations for major resistance phenotypes to elucidate their genotypic signatures. We show that phenotypic similarity does not imply genotypic similarity, that different PI-resistance mutation patterns can give rise to HIV-1 isolates with similar phenotypic profiles. Conclusion Rather than characterizing HIV-1 susceptibility toward each PI individually, our study offers a unique perspective on the phenomenon of PI class resistance by uncovering major multidrug-resistant phenotypic patterns and their often diverse genotypic determinants, providing a methodology that can be applied to understand clinically-relevant phenotypic patterns to aid in the design of novel inhibitors that

  10. Multidrug-resistant pathogens in the food supply.

    PubMed

    Doyle, Marjorie E

    2015-04-01

    Antimicrobial resistance, including multidrug resistance (MDR), is an increasing problem globally. MDR bacteria are frequently detected in humans and animals from both more- and less-developed countries and pose a serious concern for human health. Infections caused by MDR microbes may increase morbidity and mortality and require use of expensive drugs and prolonged hospitalization. Humans may be exposed to MDR pathogens through exposure to environments at health-care facilities and farms, livestock and companion animals, human food, and exposure to other individuals carrying MDR microbes. The Centers for Disease Control and Prevention classifies drug-resistant foodborne bacteria, including Campylobacter, Salmonella Typhi, nontyphoidal salmonellae, and Shigella, as serious threats. MDR bacteria have been detected in both meat and fresh produce. Salmonellae carrying genes coding for resistance to multiple antibiotics have caused numerous foodborne MDR outbreaks. While there is some level of resistance to antimicrobials in environmental bacteria, the widespread use of antibiotics in medicine and agriculture has driven the selection of a great variety of microbes with resistance to multiple antimicrobials. MDR bacteria on meat may have originated in veterinary health-care settings or on farms where animals are given antibiotics in feed or to treat infections. Fresh produce may be contaminated by irrigation or wash water containing MDR bacteria. Livestock, fruits, and vegetables may also be contaminated by food handlers, farmers, and animal caretakers who carry MDR bacteria. All potential sources of MDR bacteria should be considered and strategies devised to reduce their presence in foods. Surveillance studies have documented increasing trends in MDR in many pathogens, although there are a few reports of the decline of certain multidrug pathogens. Better coordination of surveillance programs and strategies for controlling use of antimicrobials need to be implemented in

  11. Principles for designing future regimens for multidrug-resistant tuberculosis.

    PubMed

    Brigden, Grania; Nyang'wa, Bern-Thomas; du Cros, Philipp; Varaine, Francis; Hughes, Jennifer; Rich, Michael; Horsburgh, C Robert; Mitnick, Carole D; Nuermberger, Eric; McIlleron, Helen; Phillips, Patrick P J; Balasegaram, Manica

    2014-01-01

    Fewer than 20% of patients with multidrug-resistant (MDR) tuberculosis are receiving treatment and there is an urgent need to scale up treatment programmes. One of the biggest barriers to scale-up is the treatment regimen, which is lengthy, complex, ineffective, poorly tolerated and expensive. For the first time in over 50 years, new drugs have been developed specifically to treat tuberculosis, with bedaquiline and potentially delamanid expected to be available soon for treatment of MDR cases. However, if the new drugs are merely added to the current treatment regimen, the new regimen will be at least as lengthy, cumbersome and toxic as the existing one. There is an urgent need for strategy and evidence on how to maximize the potential of the new drugs to improve outcomes and shorten treatment. We devised eight key principles for designing future treatment regimens to ensure that, once they are proven safe in clinical trials, they will be clinically effective and programmatically practicable. Regimens should contain at least one new class of drug; be broadly applicable for use against MDR and extensively drug-resistant Mycobacterium tuberculosis complex strains; contain three to five effective drugs, each from a different drug class; be delivered orally; have a simple dosing schedule; have a good side-effect profile that allows limited monitoring; last a maximum of 6 months; and have minimal interaction with antiretrovirals. Following these principles will maximize the potential of new compounds and help to overcome the clinical and programmatic disadvantages and scale-up constraints that plague the current regimen.

  12. Multidrug-resistant tuberculosis and migration to Europe.

    PubMed

    Hargreaves, S; Lönnroth, K; Nellums, L B; Olaru, I D; Nathavitharana, R R; Norredam, M; Friedland, J S

    2017-03-01

    Multidrug-resistant tuberculosis (MDR-TB) in low-incidence countries in Europe is more prevalent among migrants than the native population. The impact of the recent increase in migration to EU and EEA countries with a low incidence of TB (<20 cases per 100 000) on MDR-TB epidemiology is unclear. This narrative review synthesizes evidence on MDR-TB and migration identified through an expert panel and database search. A significant proportion of MDR-TB cases in migrants result from reactivation of latent infection. Refugees and asylum seekers may have a heightened risk of MDR-TB infection and worse outcomes. Although concerns have been raised around 'health tourists' migrating for MDR-TB treatment, numbers are probably small and data are lacking. Migrants experience significant barriers to testing and treatment for MDR-TB, exacerbated by increasingly restrictive health systems. Screening for latent MDR-TB is highly problematic because current tests cannot distinguish drug-resistant latent infection, and evidence-based guidance for treatment of latent infection in contacts of MDR patients is lacking. Although there is evidence that transmission of TB from migrants to the general population is low-it predominantly occurs within migrant communities-there is a human rights obligation to improve the diagnosis, treatment and prevention of MDR-TB in migrants. Further research is needed into MDR-TB and migration, the impact of screening on detection or prevention, and the potential consequences of failing to treat and prevent MDR-TB among migrants in Europe. An evidence-base is urgently needed to inform guidelines for effective approaches for MDR-TB management in migrant populations in Europe.

  13. Multidrug-resistant nontuberculous mycobacteria isolated from cystic fibrosis patients.

    PubMed

    Cândido, Pedro Henrique Campanini; Nunes, Luciana de Souza; Marques, Elizabeth Andrade; Folescu, Tânia Wrobel; Coelho, Fábrice Santana; de Moura, Vinicius Calado Nogueira; da Silva, Marlei Gomes; Gomes, Karen Machado; Lourenço, Maria Cristina da Silva; Aguiar, Fábio Silva; Chitolina, Fernanda; Armstrong, Derek T; Leão, Sylvia Cardoso; Neves, Felipe Piedade Gonçalves; Mello, Fernanda Carvalho de Queiroz; Duarte, Rafael Silva

    2014-08-01

    Worldwide, nontuberculous mycobacteria (NTM) have become emergent pathogens of pulmonary infections in cystic fibrosis (CF) patients, with an estimated prevalence ranging from 5 to 20%. This work investigated the presence of NTM in sputum samples of 129 CF patients (2 to 18 years old) submitted to longitudinal clinical supervision at a regional reference center in Rio de Janeiro, Brazil. From June 2009 to March 2012, 36 NTM isolates recovered from 10 (7.75%) out of 129 children were obtained. Molecular identification of NTM was performed by using PCR restriction analysis targeting the hsp65 gene (PRA-hsp65) and sequencing of the rpoB gene, and susceptibility tests were performed that followed Clinical and Laboratory Standards Institute recommendations. For evaluating the genotypic diversity, pulsed-field gel electrophoresis (PFGE) and/or enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR) was performed. The species identified were Mycobacterium abscessus subsp. bolletii (n = 24), M. abscessus subsp. abscessus (n = 6), Mycobacterium fortuitum (n = 3), Mycobacterium marseillense (n = 2), and Mycobacterium timonense (n = 1). Most of the isolates presented resistance to five or more of the antimicrobials tested. Typing profiles were mainly patient specific. The PFGE profiles indicated the presence of two clonal groups for M. abscessus subsp. abscessus and five clonal groups for M. abscesssus subsp. bolletii, with just one clone detected in two patients. Given the observed multidrug resistance patterns and the possibility of transmission between patients, we suggest the implementation of continuous and routine investigation of NTM infection or colonization in CF patients, including countries with a high burden of tuberculosis disease.

  14. The Assembly Motif of a Bacterial Small Multidrug Resistance Protein*

    PubMed Central

    Poulsen, Bradley E.; Rath, Arianna; Deber, Charles M.

    2009-01-01

    Multidrug transporters such as the small multidrug resistance (SMR) family of bacterial integral membrane proteins are capable of conferring clinically significant resistance to a variety of common therapeutics. As antiporter proteins of ∼100 amino acids, SMRs must self-assemble into homo-oligomeric structures for efflux of drug molecules. Oligomerization centered at transmembrane helix four (TM4) has been implicated in SMR assembly, but the full complement of residues required to mediate its self-interaction remains to be characterized. Here, we use Hsmr, the 110-residue SMR family member of the archaebacterium Halobacterium salinarum, to determine the TM4 residue motif required to mediate drug resistance and SMR self-association. Twelve single point mutants that scan the central portion of the TM4 helix (residues 85–104) were constructed and were tested for their ability to confer resistance to the cytotoxic compound ethidium bromide. Six residues were found to be individually essential for drug resistance acti