Rapid computational identification of the targets of protein kinase inhibitors.

PubMed

Rockey, William M; Elcock, Adrian H

2005-06-16

We describe a method for rapidly computing the relative affinities of an inhibitor for all individual members of a family of homologous receptors. The approach, implemented in a new program, SCR, models inhibitor-receptor interactions in full atomic detail with an empirical energy function and includes an explicit account of flexibility in homology-modeled receptors through sampling of libraries of side chain rotamers. SCR's general utility was demonstrated by application to seven different protein kinase inhibitors: for each inhibitor, relative binding affinities with panels of approximately 20 protein kinases were computed and compared with experimental data. For five of the inhibitors (SB203580, purvalanol B, imatinib, H89, and hymenialdisine), SCR provided excellent reproduction of the experimental trends and, importantly, was capable of identifying the targets of inhibitors even when they belonged to different kinase families. The method's performance in a predictive setting was demonstrated by performing separate training and testing applications, and its key assumptions were tested by comparison with a number of alternative approaches employing the ligand-docking program AutoDock (Morris et al. J. Comput. Chem. 1998, 19, 1639-1662). These comparison tests included using AutoDock in nondocking and docking modes and performing energy minimizations of inhibitor-kinase complexes with the molecular mechanics code GROMACS (Berendsen et al. Comput. Phys. Commun. 1995, 91, 43-56). It was found that a surprisingly important aspect of SCR's approach is its assumption that the inhibitor be modeled in the same orientation for each kinase: although this assumption is in some respects unrealistic, calculations that used apparently more realistic approaches produced clearly inferior results. Finally, as a large-scale application of the method, SB203580, purvalanol B, and imatinib were screened against an almost full complement of 493 human protein kinases using SCR in

A Targeted Quantitative Proteomics Strategy for Global Kinome Profiling of Cancer Cells and Tissues*

PubMed Central

Xiao, Yongsheng; Guo, Lei; Wang, Yinsheng

2014-01-01

Kinases are among the most intensively pursued enzyme superfamilies as targets for anti-cancer drugs. Large data sets on inhibitor potency and selectivity for more than 400 human kinases became available recently, offering the opportunity to design rationally novel kinase-based anti-cancer therapies. However, the expression levels and activities of kinases are highly heterogeneous among different types of cancer and even among different stages of the same cancer. The lack of effective strategy for profiling the global kinome hampers the development of kinase-targeted cancer chemotherapy. Here, we introduced a novel global kinome profiling method, based on our recently developed isotope-coded ATP-affinity probe and a targeted proteomic method using multiple-reaction monitoring (MRM), for assessing simultaneously the expression of more than 300 kinases in human cells and tissues. This MRM-based assay displayed much better sensitivity, reproducibility, and accuracy than the discovery-based shotgun proteomic method. Approximately 250 kinases could be routinely detected in the lysate of a single cell line. Additionally, the incorporation of iRT into MRM kinome library rendered our MRM kinome assay easily transferrable across different instrument platforms and laboratories. We further employed this approach for profiling kinase expression in two melanoma cell lines, which revealed substantial kinome reprogramming during cancer progression and demonstrated an excellent correlation between the anti-proliferative effects of kinase inhibitors and the expression levels of their target kinases. Therefore, this facile and accurate kinome profiling assay, together with the kinome-inhibitor interaction map, could provide invaluable knowledge to predict the effectiveness of kinase inhibitor drugs and offer the opportunity for individualized cancer chemotherapy. PMID:24520089

Tissue Factor Pathway Inhibitor: Multiple Anticoagulant Activities for a Single Protein.

PubMed

Mast, Alan E

2016-01-01

Tissue factor (TF) pathway inhibitor (TFPI) is an anticoagulant protein that inhibits early phases of the procoagulant response. Alternatively spliced isoforms of TFPI are differentially expressed by endothelial cells and human platelets and plasma. The TFPIβ isoform localizes to the endothelium surface where it is a potent inhibitor of TF-factor VIIa complexes that initiate blood coagulation. The TFPIα isoform is present in platelets. TFPIα contains a stretch of 9 amino acids nearly identical to those found in the B-domain of factor V that are well conserved in mammals. These amino acids provide exosite binding to activated factor V, which allows for TFPIα to inhibit prothrombinase during the initiation phase of blood coagulation. Endogenous inhibition at this point in the coagulation cascade was only recently recognized and has provided a biochemical rationale to explain the pathophysiological mechanisms underlying several clinical disorders. These include the east Texas bleeding disorder that is caused by production of an altered form of factor V with high affinity for TFPI and a paradoxical procoagulant effect of heparins. In addition, these findings have led to ideas for pharmacological targeting of TFPI that may reduce bleeding in hemophilia patients. © 2015 American Heart Association, Inc.

Targeting SHP2 for EGFR inhibitor resistant non-small cell lung carcinoma

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

Xu, Jie; Zeng, Li-Fan; Shen, Weihua

Highlights: •SHP2 is required for EGFR inhibitor resistant NSCLC H1975 cell proliferation. •SHP2 inhibitor blocks EGF-stimulated ERK1/2 activation and proliferation. •SHP2 inhibitor exhibits marked anti-tumor activity in H1975 xenograft mice. •SHP2 inhibitor synergizes with PI3K inhibitor in suppressing cell growth. •Targeting SHP2 represents a novel strategy for EGFR inhibitor resistant NSCLCs. -- Abstract: Targeted therapy with inhibitors of epidermal growth factor receptor (EGFR) has produced a noticeable benefit to non-small cell lung cancer (NSCLC) patients whose tumors carry activating mutations (e.g. L858R) in EGFR. Unfortunately, these patients develop drug resistance after treatment, due to acquired secondary gatekeeper mutations in EGFRmore » (e.g. T790M). Given the critical role of SHP2 in growth factor receptor signaling, we sought to determine whether targeting SHP2 could have therapeutic value for EGFR inhibitor resistant NSCLC. We show that SHP2 is required for EGF-stimulated ERK1/2 phosphorylation and proliferation in EGFR inhibitor resistant NSCLC cell line H1975, which harbors the EGFR T790M/L858R double-mutant. We demonstrate that treatment of H1975 cells with II-B08, a specific SHP2 inhibitor, phenocopies the observed growth inhibition and reduced ERK1/2 activation seen in cells treated with SHP2 siRNA. Importantly, we also find that II-B08 exhibits marked anti-tumor activity in H1975 xenograft mice. Finally, we observe that combined inhibition of SHP2 and PI3K impairs both the ERK1/2 and PI3K/AKT signaling axes and produces significantly greater effects on repressing H1975 cell growth than inhibition of either protein individually. Collectively, these results suggest that targeting SHP2 may represent an effective strategy for treatment of EGFR inhibitor resistant NSCLCs.« less

The tissue-type plasminogen activator–plasminogen activator inhibitor 1 complex promotes neurovascular injury in brain trauma: evidence from mice and humans

PubMed Central

Sashindranath, Maithili; Sales, Eunice; Daglas, Maria; Freeman, Roxann; Samson, Andre L.; Cops, Elisa J.; Beckham, Simone; Galle, Adam; McLean, Catriona; Morganti-Kossmann, Cristina; Rosenfeld, Jeffrey V.; Madani, Rime; Vassalli, Jean-Dominique; Su, Enming J.; Lawrence, Daniel A.

2012-01-01

metalloproteinase-3. Accordingly, pharmacological inhibition of matrix metalloproteinase-3 attenuates neurovascular permeability and improves neurological function in injured mice. Our results are clinically relevant, because concentrations of tissue plasminogen activator: plasminogen activator inhibitor-1 complex and matrix metalloproteinase-3 are significantly elevated in cerebrospinal fluid of trauma patients and correlate with neurological outcome. In a separate study, we found that matrix metalloproteinase-3 and albumin, a marker of cerebrovascular damage, were significantly increased in brain tissue of patients with neurotrauma. Perturbation of neurovascular homeostasis causing oedema, inflammation and cell death is an important cause of acute and long-term neurological dysfunction after trauma. A role for the tissue plasminogen activator–matrix metalloproteinase axis in promoting neurovascular disruption after neurotrauma has not been described thus far. Targeting tissue plasminogen activator: plasminogen activator inhibitor-1 complex signalling or downstream matrix metalloproteinase-3 induction may provide viable therapeutic strategies to reduce cerebrovascular permeability after neurotrauma. PMID:22822039

21 CFR 500.86 - Marker residue and target tissue.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Marker residue and target tissue. 500.86 Section...-Producing Animals § 500.86 Marker residue and target tissue. (a) For each edible tissue, the sponsor shall...) From these data, FDA will select a target tissue and a marker residue and designate the concentration...

21 CFR 500.86 - Marker residue and target tissue.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Marker residue and target tissue. 500.86 Section...-Producing Animals § 500.86 Marker residue and target tissue. (a) For each edible tissue, the sponsor shall...) From these data, FDA will select a target tissue and a marker residue and designate the concentration...

CS2164, a novel multi-target inhibitor against tumor angiogenesis, mitosis and chronic inflammation with anti-tumor potency.

PubMed

Zhou, You; Shan, Song; Li, Zhi-Bin; Xin, Li-Jun; Pan, De-Si; Yang, Qian-Jiao; Liu, Ying-Ping; Yue, Xu-Peng; Liu, Xiao-Rong; Gao, Ji-Zhou; Zhang, Jin-Wen; Ning, Zhi-Qiang; Lu, Xian-Ping

2017-03-01

Although inhibitors targeting tumor angiogenic pathway have provided improvement for clinical treatment in patients with various solid tumors, the still very limited anti-cancer efficacy and acquired drug resistance demand new agents that may offer better clinical benefits. In the effort to find a small molecule potentially targeting several key pathways for tumor development, we designed, discovered and evaluated a novel multi-kinase inhibitor, CS2164. CS2164 inhibited the angiogenesis-related kinases (VEGFR2, VEGFR1, VEGFR3, PDGFRα and c-Kit), mitosis-related kinase Aurora B and chronic inflammation-related kinase CSF-1R in a high potency manner with the IC 50 at a single-digit nanomolar range. Consequently, CS2164 displayed anti-angiogenic activities through suppression of VEGFR/PDGFR phosphorylation, inhibition of ligand-dependent cell proliferation and capillary tube formation, and prevention of vasculature formation in tumor tissues. CS2164 also showed induction of G2/M cell cycle arrest and suppression of cell proliferation in tumor tissues through the inhibition of Aurora B-mediated H3 phosphorylation. Furthermore, CS2164 demonstrated the inhibitory effect on CSF-1R phosphorylation that led to the suppression of ligand-stimulated monocyte-to-macrophage differentiation and reduced CSF-1R + cells in tumor tissues. The in vivo animal efficacy studies revealed that CS2164 induced remarkable regression or complete inhibition of tumor growth at well-tolerated oral doses in several human tumor xenograft models. Collectively, these results indicate that CS2164 is a highly selective multi-kinase inhibitor with potent anti-tumor activities against tumor angiogenesis, mitosis and chronic inflammation, which may provide the rationale for further clinical assessment of CS2164 as a therapeutic agent in the treatment of cancer. © 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

Maturation inhibitors: a new therapeutic class targets the virus structure.

PubMed

Salzwedel, Karl; Martin, David E; Sakalian, Michael

2007-01-01

The current standard of care for HIV/AIDS in the developed world is HAART therapy, usually a combination of two reverse transcriptase inhibitors and a protease inhibitor. Despite the success of this regimen, there is a continuing need for new drug options to overcome problems with tolerability and the emergence of viral resistance. In this review we discuss the discovery of a potential new class of antiretroviral therapeutics, known as maturation inhibitors, and the development of the first-in-class compound, bevirimat. Bevirimat is distinguished from the currently available antiretrovirals by its unique target and mode of action. While the specific interactions responsible for activity have yet to be fully characterized, it is clear that the target for bevirimat is the Gag polyprotein precursor, the main structural protein responsible for assembly and budding of virion particles. As basic research continues on the precise mechanism of action of bevirimat, clinical development is progressing, with demonstration of both safety and efficacy in early-stage trials. These encouraging results, coupled with the discovery and development of future generations of maturation inhibitors, suggest that maturation inhibitors may be added to the growing set of tools available to control HIV/AIDS.

Chemical Proteomics Reveals Ferrochelatase as a Common Off-target of Kinase Inhibitors.

PubMed

Klaeger, Susan; Gohlke, Bjoern; Perrin, Jessica; Gupta, Vipul; Heinzlmeir, Stephanie; Helm, Dominic; Qiao, Huichao; Bergamini, Giovanna; Handa, Hiroshi; Savitski, Mikhail M; Bantscheff, Marcus; Médard, Guillaume; Preissner, Robert; Kuster, Bernhard

2016-05-20

Many protein kinases are valid drug targets in oncology because they are key components of signal transduction pathways. The number of clinical kinase inhibitors is on the rise, but these molecules often exhibit polypharmacology, potentially eliciting desired and toxic effects. Therefore, a comprehensive assessment of a compound's target space is desirable for a better understanding of its biological effects. The enzyme ferrochelatase (FECH) catalyzes the conversion of protoporphyrin IX into heme and was recently found to be an off-target of the BRAF inhibitor Vemurafenib, likely explaining the phototoxicity associated with this drug in melanoma patients. This raises the question of whether FECH binding is a more general feature of kinase inhibitors. To address this, we applied a chemical proteomics approach using kinobeads to evaluate 226 clinical kinase inhibitors for their ability to bind FECH. Surprisingly, low or submicromolar FECH binding was detected for 29 of all compounds tested and isothermal dose response measurements confirmed target engagement in cells. We also show that Vemurafenib, Linsitinib, Neratinib, and MK-2461 reduce heme levels in K562 cells, verifying that drug binding leads to a loss of FECH activity. Further biochemical and docking experiments identified the protoporphyrin pocket in FECH as one major drug binding site. Since the genetic loss of FECH activity leads to photosensitivity in humans, our data strongly suggest that FECH inhibition by kinase inhibitors is the molecular mechanism triggering photosensitivity in patients. We therefore suggest that a FECH assay should generally be part of the preclinical molecular toxicology package for the development of kinase inhibitors.

Trypsinogen 4 boosts tumor endothelial cells migration through proteolysis of tissue factor pathway inhibitor-2.

PubMed

Ghilardi, Carmen; Silini, Antonietta; Figini, Sara; Anastasia, Alessia; Lupi, Monica; Fruscio, Robert; Giavazzi, Raffaella; Bani, Maria Rosa

2015-09-29

Proteases contribute to cancer in many ways, including tumor vascularization and metastasis, and their pharmacological inhibition is a potential anticancer strategy. We report that human endothelial cells (EC) express the trypsinogen 4 isoform of the serine protease 3 (PRSS3), and lack both PRSS2 and PRSS1. Trypsinogen 4 expression was upregulated by the combined action of VEGF-A, FGF-2 and EGF, angiogenic factors representative of the tumor microenvironment. Suppression of trypsinogen 4 expression by siRNA inhibited the angiogenic milieu-induced migration of EC from cancer specimens (tumor-EC), but did not affect EC from normal tissues. We identified tissue factor pathway inhibitor-2 (TFPI-2), a matrix associated inhibitor of cell motility, as the functional target of trypsinogen 4, which cleaved TFPI-2 and removed it from the matrix put down by tumor-EC. Silencing tumor-EC for trypsinogen 4 accumulated TFPI2 in the matrix. Showing that angiogenic factors stimulate trypsinogen 4 expression, which hydrolyses TFPI-2 favoring a pro-migratory situation, our study suggests a new pathway linking tumor microenvironment signals to endothelial cell migration, which is essential for angiogenesis and blood vessel remodeling. Abolishing trypsinogen 4 functions might be an exploitable strategy as anticancer, particularly anti-vascular, therapy.

Trypsinogen 4 boosts tumor endothelial cells migration through proteolysis of tissue factor pathway inhibitor-2

PubMed Central

Ghilardi, Carmen; Silini, Antonietta; Figini, Sara; Anastasia, Alessia; Lupi, Monica; Fruscio, Robert; Giavazzi, Raffaella; Bani, MariaRosa

2015-01-01

Proteasescontribute to cancer in many ways, including tumor vascularization and metastasis, and their pharmacological inhibition is a potential anticancer strategy. We report that human endothelial cells (EC) express the trypsinogen 4 isoform of the serine protease 3 (PRSS3), and lack both PRSS2 and PRSS1. Trypsinogen 4 expression was upregulated by the combined action of VEGF-A, FGF-2 and EGF, angiogenic factors representative of the tumor microenvironment. Suppression of trypsinogen 4 expression by siRNA inhibited the angiogenic milieu-induced migration of EC from cancer specimens (tumor-EC), but did not affect EC from normal tissues. We identified tissue factor pathway inhibitor-2 (TFPI-2), a matrix associated inhibitor of cell motility, as the functional target of trypsinogen 4, which cleaved TFPI-2 and removed it from the matrix put down by tumor-EC. Silencing tumor-EC for trypsinogen 4 accumulated TFPI2 in the matrix. Showing that angiogenic factors stimulate trypsinogen 4 expression, which hydrolyses TFPI-2 favoring a pro-migratory situation, our study suggests a new pathway linking tumor microenvironment signals to endothelial cell migration, which is essential for angiogenesis and blood vessel remodeling. Abolishing trypsinogen 4 functions might be an exploitable strategy as anticancer, particularly anti-vascular, therapy. PMID:26318044

Repositioning Proton Pump Inhibitors as Anticancer Drugs by Targeting the Thioesterase Domain of Human Fatty Acid Synthase

PubMed Central

2015-01-01

Fatty acid synthase (FASN), the enzyme responsible for de novo synthesis of free fatty acids, is up-regulated in many cancers. FASN is essential for cancer cell survival and contributes to drug resistance and poor prognosis. However, it is not expressed in most nonlipogenic normal tissues. Thus, FASN is a desirable target for drug discovery. Although different FASN inhibitors have been identified, none has successfully moved into clinical use. In this study, using in silico screening of an FDA-approved drug database, we identified proton pump inhibitors (PPIs) as effective inhibitors of the thioesterase activity of human FASN. Further investigation showed that PPIs inhibited proliferation and induced apoptosis of cancer cells. Supplementation of palmitate, the end product of FASN catalysis, rescued cancer cells from PPI-induced cell death. These findings provide new evidence for the mechanism by which this FDA-approved class of compounds may be acting on cancer cells. PMID:25513712

Discovery of Novel Inhibitors and Fluorescent Probe Targeting NAMPT.

PubMed

Wang, Xia; Xu, Tian-Ying; Liu, Xin-Zhu; Zhang, Sai-Long; Wang, Pei; Li, Zhi-Yong; Guan, Yun-Feng; Wang, Shu-Na; Dong, Guo-Qiang; Zhuo, Shu; Le, Ying-Ying; Sheng, Chun-Quan; Miao, Chao-Yu

2015-07-31

Nicotinamide phosphoribosyltransferase (NAMPT) is a promising antitumor target. Novel NAMPT inhibitors with diverse chemotypes are highly desirable for development of antitumor agents. Using high throughput screening system targeting NAMPT on a chemical library of 30000 small-molecules, we found a non-fluorescent compound F671-0003 and a fluorescent compound M049-0244 with excellent in vitro activity (IC50: 85 nM and 170 nM respectively) and anti-proliferative activity against HepG2 cells. These two compounds significantly depleted cellular NAD levels. Exogenous NMN rescued their anti-proliferative activity against HepG2 cells. Structure-activity relationship study proposed a binding mode for NAMPT inhibitor F671-0003 and highlighted the importance of hydrogen bonding, hydrophobic and π-π interactions in inhibitor binding. Imaging study provided the evidence that fluorescent compound M049-0244 (3 μM) significantly stained living HepG2 cells. Cellular fluorescence was further verified to be NAMPT dependent by using RNA interference and NAMPT over expression transgenic mice. Our findings provide novel antitumor lead compounds and a "first-in-class" fluorescent probe for imaging NAMPT.

Pericyte-targeting drug delivery and tissue engineering.

PubMed

Kang, Eunah; Shin, Jong Wook

2016-01-01

Pericytes are contractile mural cells that wrap around the endothelial cells of capillaries and venules. Depending on the triggers by cellular signals, pericytes have specific functionality in tumor microenvironments, properties of potent stem cells, and plasticity in cellular pathology. These features of pericytes can be activated for the promotion or reduction of angiogenesis. Frontier studies have exploited pericyte-targeting drug delivery, using pericyte-specific peptides, small molecules, and DNA in tumor therapy. Moreover, the communication between pericytes and endothelial cells has been applied to the induction of vessel neoformation in tissue engineering. Pericytes may prove to be a novel target for tumor therapy and tissue engineering. The present paper specifically reviews pericyte-specific drug delivery and tissue engineering, allowing insight into the emerging research targeting pericytes.

New Targets and Inhibitors of Mycobacterial Sulfur Metabolism§

PubMed Central

Paritala, Hanumantharao; Carroll, Kate S.

2015-01-01

The identification of new antibacterial targets is urgently needed to address multidrug resistant and latent tuberculosis infection. Sulfur metabolic pathways are essential for survival and the expression of virulence in many pathogenic bacteria, including Mycobacterium tuberculosis. In addition, microbial sulfur metabolic pathways are largely absent in humans and therefore, represent unique targets for therapeutic intervention. In this review, we summarize our current understanding of the enzymes associated with the production of sulfated and reduced sulfur-containing metabolites in Mycobacteria. Small molecule inhibitors of these catalysts represent valuable chemical tools that can be used to investigate the role of sulfur metabolism throughout the Mycobacterial lifecycle and may also represent new leads for drug development. In this light, we also summarize recent progress made in the development of inhibitors of sulfur metabolism enzymes. PMID:23808874

Role of tissue-type plasminogen activator and plasminogen activator inhibitor-1 in psychological stress and depression.

PubMed

Tsai, Shih-Jen

2017-12-22

Major depressive disorder is a common illness worldwide, but the pathogenesis of the disorder remains incompletely understood. The tissue-type plasminogen activator-plasminogen proteolytic cascade is highly expressed in the brain regions involved in mood regulation and neuroplasticity. Accumulating evidence from animal and human studies suggests that tissue-type plasminogen activator and its chief inhibitor, plasminogen activator inhibitor-1, are related to stress reaction and depression. Furthermore, the neurotrophic hypothesis of depression postulates that compromised neurotrophin brain-derived neurotrophic factor (BDNF) function is directly involved in the pathophysiology of depression. In the brain, the proteolytic cleavage of proBDNF, a BDNF precursor, to mature BDNF through plasmin represents one mechanism that can change the direction of BDNF action. We also discuss the implications of tissue-type plasminogen activator and plasminogen activator inhibitor-1 alterations as biomarkers for major depressive disorder. Using drugs that increase tissue-type plasminogen activator or decrease plasminogen activator inhibitor-1 levels may open new avenues to develop conceptually novel therapeutic strategies for depression treatment.

HIV-1 Gag as an Antiviral Target: Development of Assembly and Maturation Inhibitors.

PubMed

Spearman, Paul

2016-01-01

HIV-1 Gag is the master orchestrator of particle assembly. The central role of Gag at multiple stages of the HIV lifecycle has led to efforts to develop drugs that directly target Gag and prevent the formation and release of infectious particles. Until recently, however, only the catalytic site protease inhibitors have been available to inhibit late stages of HIV replication. This review summarizes the current state of development of antivirals that target Gag or disrupt late events in the retrovirus lifecycle such as maturation of the viral capsid. Maturation inhibitors represent an exciting new series of antiviral compounds, including those that specifically target CA-SP1 cleavage and the allosteric integrase inhibitors that inhibit maturation by a completely different mechanism. Numerous small molecules and peptides targeting CA have been studied in attempts to disrupt steps in assembly. Efforts to target CA have recently gained considerable momentum from the development of small molecules that bind CA and alter capsid stability at the post-entry stage of the lifecycle. Efforts to develop antivirals that inhibit incorporation of genomic RNA or to inhibit late budding events remain in preliminary stages of development. Overall, the development of novel antivirals targeting Gag and the late stages in HIV replication appears much closer to success than ever, with the new maturation inhibitors leading the way.

Epitope targeting of tertiary protein structure enables target-guided synthesis of a potent in-cell inhibitor of botulinum neurotoxin.

PubMed

Farrow, Blake; Wong, Michelle; Malette, Jacquie; Lai, Bert; Deyle, Kaycie M; Das, Samir; Nag, Arundhati; Agnew, Heather D; Heath, James R

2015-06-08

Botulinum neurotoxin (BoNT) serotype A is the most lethal known toxin and has an occluded structure, which prevents direct inhibition of its active site before it enters the cytosol. Target-guided synthesis by in situ click chemistry is combined with synthetic epitope targeting to exploit the tertiary structure of the BoNT protein as a landscape for assembling a competitive inhibitor. A substrate-mimicking peptide macrocycle is used as a direct inhibitor of BoNT. An epitope-targeting in situ click screen is utilized to identify a second peptide macrocycle ligand that binds to an epitope that, in the folded BoNT structure, is active-site-adjacent. A second in situ click screen identifies a molecular bridge between the two macrocycles. The resulting divalent inhibitor exhibits an in vitro inhibition constant of 165 pM against the BoNT/A catalytic chain. The inhibitor is carried into cells by the intact holotoxin, and demonstrates protection and rescue of BoNT intoxication in a human neuron model. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Peptide-targeted, stimuli-responsive polymersomes for delivering a cancer stemness inhibitor to cancer stem cell microtumors.

PubMed

Karandish, Fataneh; Froberg, James; Borowicz, Pawel; Wilkinson, John C; Choi, Yongki; Mallik, Sanku

2018-03-01

Often cancer relapses after an initial response to chemotherapy because of the tumor's heterogeneity and the presence of progenitor stem cells, which can renew. To overcome drug resistance, metastasis, and relapse in cancer, a promising approach is the inhibition of cancer stemness. In this study, the expression of the neuropilin-1 receptor in both pancreatic and prostate cancer stem cells was identified and targeted with a stimuli-responsive, polymeric nanocarrier to deliver a stemness inhibitor (napabucasin) to cancer stem cells. Reduction-sensitive amphiphilic block copolymers PEG 1900 -S-S-PLA 6000 and the N 3 -PEG 1900 -PLA 6000 were synthesized. The tumor penetrating iRGD peptide-hexynoic acid conjugate was linked to the N 3 -PEG 1900 -PLA 6000 polymer via a Cu 2+ catalyzed "Click" reaction. Subsequently, this peptide-polymer conjugate was incorporated into polymersomes for tumor targeting and tissue penetration. We prepared polymersomes containing 85% PEG 1900 -S-S-PLA 6000 , 10% iRGD-polymer conjugate, and 5% DPPE-lissamine rhodamine dye. The iRGD targeted polymersomes encapsulating the cancer stemness inhibitor napabucasin were internalized in both prostate and pancreatic cancer stem cells. The napabucasin encapsulated polymersomes significantly (p < .05) reduced the viability of both prostate and pancreatic cancer stem cells and decreased the stemness protein expression notch-1 and nanog compared to the control and vesicles without any drug. The napabucasin encapsulated polymersome formulations have the potential to lead to a new direction in prostate and pancreatic cancer therapy by penetrating deeply into the tumors, releasing the encapsulated stemness inhibitor, and killing cancer stem cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Targeting of KRAS mutant tumors by HSP90 inhibitors involves degradation of STK33

PubMed Central

Azoitei, Ninel; Hoffmann, Christopher M.; Ellegast, Jana M.; Ball, Claudia R.; Obermayer, Kerstin; Gößele, Ulrike; Koch, Britta; Faber, Katrin; Genze, Felicitas; Schrader, Mark; Kestler, Hans A.; Döhner, Hartmut; Chiosis, Gabriela; Glimm, Hanno

2012-01-01

Previous efforts to develop drugs that directly inhibit the activity of mutant KRAS, the most commonly mutated human oncogene, have not been successful. Cancer cells driven by mutant KRAS require expression of the serine/threonine kinase STK33 for their viability and proliferation, identifying STK33 as a context-dependent therapeutic target. However, specific strategies for interfering with the critical functions of STK33 are not yet available. Here, using a mass spectrometry-based screen for STK33 protein interaction partners, we report that the HSP90/CDC37 chaperone complex binds to and stabilizes STK33 in human cancer cells. Pharmacologic inhibition of HSP90, using structurally divergent small molecules currently in clinical development, induced proteasome-mediated degradation of STK33 in human cancer cells of various tissue origin in vitro and in vivo, and triggered apoptosis preferentially in KRAS mutant cells in an STK33-dependent manner. Furthermore, HSP90 inhibitor treatment impaired sphere formation and viability of primary human colon tumor-initiating cells harboring mutant KRAS. These findings provide mechanistic insight into the activity of HSP90 inhibitors in KRAS mutant cancer cells, indicate that the enhanced requirement for STK33 can be exploited to target mutant KRAS-driven tumors, and identify STK33 depletion through HSP90 inhibition as a biomarker-guided therapeutic strategy with immediate translational potential. PMID:22451720

21 CFR 500.86 - Marker residue and target tissue.

Code of Federal Regulations, 2012 CFR

2012-04-01

...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS GENERAL Regulation of Carcinogenic Compounds Used in Food-Producing Animals § 500.86 Marker residue and target tissue. (a) For each edible tissue, the sponsor shall... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Marker residue and target tissue. 500.86 Section...

21 CFR 500.86 - Marker residue and target tissue.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS GENERAL Regulation of Carcinogenic Compounds Used in Food-Producing Animals § 500.86 Marker residue and target tissue. (a) For each edible tissue, the sponsor shall... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Marker residue and target tissue. 500.86 Section...

21 CFR 500.86 - Marker residue and target tissue.

Code of Federal Regulations, 2013 CFR

2013-04-01

...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS GENERAL Regulation of Carcinogenic Compounds Used in Food-Producing Animals § 500.86 Marker residue and target tissue. (a) For each edible tissue, the sponsor shall... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Marker residue and target tissue. 500.86 Section...

Targeted in-vivo computed tomography (CT) imaging of tissue ACE using concentrated lisinopril-capped gold nanoparticle solutions

NASA Astrophysics Data System (ADS)

Daniel, Marie-Christine; Aras, Omer; Smith, Mark F.; Nan, Anjan; Fleiter, Thorsten

2010-04-01

The development of cardiac and pulmonary fibrosis have been associated with overexpression of angiotensin-converting enzyme (ACE). Moreover, ACE inhibitors, such as lisinopril, have shown a benificial effect for patients diagnosed with heart failure or systemic hypertension. Thus targeted imaging of the ACE is of crucial importance for monitoring of the tissue ACE activity as well as the treatment efficacy in heart failure. In this respect, lisinopril-capped gold nanoparticles were prepared to provide a new type of probe for targeted molecular imaging of ACE by tuned K-edge computed tomography (CT) imaging. Concentrated solutions of these modified gold nanoparticles, with a diameter around 16 nm, showed high contrast in CT imaging. These new targeted imaging agents were thus used for in vivo imaging on rat models.

Targeting histone deacetylase inhibitors for anti-malarial therapy.

PubMed

Andrews, Katherine T; Tran, Thanh N; Wheatley, Nicole C; Fairlie, David P

2009-01-01

It is now clear that histone acetylation plays key roles in regulating gene transcription in both eukaryotes and prokaryotes, the acetylated form inducing gene expression while deacetylation silences genes. Recent studies have identified roles for histone acetyltransferases (HATs) and/or histone deacetylases (HDACs) in a number of parasites including Entamoeba histolytica, Toxoplasma gondii, Schistosoma mansoni, Cryptosporidium sp., Leishmania donovani, Neospora caninum, and Plasmodium falciparum. Here we survey fairly limited efforts to date in profiling antimalarial activities of HDAC inhibitors, showing that such compounds are potent inhibitors of the growth of P. falciparum in vitro and in vivo. Most of the compounds evaluated so far have borne a zinc-binding hydroxamate group that tends to be metabolized in vivo, and thus new zinc-binding groups need to be incorporated into second generation inhibitors in order to mask the catalytic zinc in the active site of HDACs. Also the development of compounds that are selective for parasitic HDACs over mammalian HDACs is still in relative infancy and it will take some time to derive antiparasitic HDAC inhibitor compounds with minimal toxicity for the host and acceptable pharmacokinetic and pharmacodynamic profiles for human treatment. Nevertheless, results to date suggest that HDAC inhibitor development represents a promising new approach to the potential treatment of parasitic infections, including those induced by malaria protozoa, and may offer new therapeutic targets within increasingly drug-resistant malarial parasites.

Development of Small-molecule HIV Entry Inhibitors Specifically Targeting gp120 or gp41

PubMed Central

Lu, Lu; Yu, Fei; Cai, Lifeng; Debnath, Asim K.; Jiang, Shibo

2015-01-01

Human immunodeficiency virus type 1 (HIV-1) envelope (Env) glycoprotein surface subunit gp120 and transmembrane subunit gp41 play important roles in HIV-1 entry, thus serving as key targets for the development of HIV-1 entry inhibitors. T20 peptide (enfuvirtide) is the first U.S. FDA-approved HIV entry inhibitor; however, its clinical application is limited by the lack of oral availability. Here, we have described the structure and function of the HIV-1 gp120 and gp41 subunits and reviewed advancements in the development of small-molecule HIV entry inhibitors specifically targeting these two Env glycoproteins. We then compared the advantages and disadvantages of different categories of HIV entry inhibitor candidates and further predicted the future trend of HIV entry inhibitor development. PMID:26324044

Combinatorial support vector machines approach for virtual screening of selective multi-target serotonin reuptake inhibitors from large compound libraries.

PubMed

Shi, Z; Ma, X H; Qin, C; Jia, J; Jiang, Y Y; Tan, C Y; Chen, Y Z

2012-02-01

Selective multi-target serotonin reuptake inhibitors enhance antidepressant efficacy. Their discovery can be facilitated by multiple methods, including in silico ones. In this study, we developed and tested an in silico method, combinatorial support vector machines (COMBI-SVMs), for virtual screening (VS) multi-target serotonin reuptake inhibitors of seven target pairs (serotonin transporter paired with noradrenaline transporter, H(3) receptor, 5-HT(1A) receptor, 5-HT(1B) receptor, 5-HT(2C) receptor, melanocortin 4 receptor and neurokinin 1 receptor respectively) from large compound libraries. COMBI-SVMs trained with 917-1951 individual target inhibitors correctly identified 22-83.3% (majority >31.1%) of the 6-216 dual inhibitors collected from literature as independent testing sets. COMBI-SVMs showed moderate to good target selectivity in misclassifying as dual inhibitors 2.2-29.8% (majority <15.4%) of the individual target inhibitors of the same target pair and 0.58-7.1% of the other 6 targets outside the target pair. COMBI-SVMs showed low dual inhibitor false hit rates (0.006-0.056%, 0.042-0.21%, 0.2-4%) in screening 17 million PubChem compounds, 168,000 MDDR compounds, and 7-8181 MDDR compounds similar to the dual inhibitors. Compared with similarity searching, k-NN and PNN methods, COMBI-SVM produced comparable dual inhibitor yields, similar target selectivity, and lower false hit rate in screening 168,000 MDDR compounds. The annotated classes of many COMBI-SVMs identified MDDR virtual hits correlate with the reported effects of their predicted targets. COMBI-SVM is potentially useful for searching selective multi-target agents without explicit knowledge of these agents. Copyright © 2011 Elsevier Inc. All rights reserved.

Targeting Inflammation in Heart Failure with Histone Deacetylase Inhibitors

PubMed Central

McKinsey, Timothy A

2011-01-01

Cardiovascular insults such as myocardial infarction and chronic hypertension can trigger the heart to undergo a remodeling process characterized by myocyte hypertrophy, myocyte death and fibrosis, often resulting in impaired cardiac function and heart failure. Pathological cardiac remodeling is associated with inflammation, and therapeutic approaches targeting inflammatory cascades have shown promise in patients with heart failure. Small molecule histone deacetylase (HDAC) inhibitors block adverse cardiac remodeling in animal models, suggesting unforeseen potential for this class of compounds for the treatment of heart failure. In addition to their beneficial effects on myocardial cells, HDAC inhibitors have potent antiinflammatory actions. This review highlights the roles of HDACs in the heart and the potential for using HDAC inhibitors as broad-based immunomodulators for the treatment of human heart failure. PMID:21267510

Plasmin-dependent proteolysis of Tissue Factor Pathway Inhibitor in a mouse model of endotoxemia

PubMed Central

Lupu, Cristina; Herlea, Oana; Tang, Haiwang; Lijnen, Roger H.; Lupu, Florea

2012-01-01

Summary Background Development of a procoagulant state in sepsis, due to aberrant expression of tissue factor (TF) and sharp decrease of its major inhibitor tissue factor pathway inhibitor (TFPI), could lead to microthrombotic organ failure. The mechanism for the decline of TFPI activity in the lung could involve plasmin-mediated cleavage of the inhibitor. Objective To investigate the effect of plasmin generation on lung-associated TFPI activity, in normal conditions and during infusion of endotoxin (LPS) in mice. Methods Plasmin generation and TFPI activity were assayed in the lungs of mice deficient of tissue-type plasminogen activator (t-PA) or plasminogen (Plg), at 2-hrs after LPS or saline injection. Results The sharp loss of lung-associated TFPI activity at 2-hrs post LPS paralleled the abrupt increase of plasmin generation. TFPI activity was significantly retained in both t-PA-/- and Plg-/- mice, which are unable to generate plasmin. Conclusion The increased plasmin generation during the early stages of sepsis could cleave/inactivate TFPI and thus lead to thrombotic complications. PMID:23106863

Activation loop targeting strategy for design of receptor-interacting protein kinase 2 (RIPK2) inhibitors.

PubMed

Suebsuwong, Chalada; Pinkas, Daniel M; Ray, Soumya S; Bufton, Joshua C; Dai, Bing; Bullock, Alex N; Degterev, Alexei; Cuny, Gregory D

2018-02-15

Development of selective kinase inhibitors remains a challenge due to considerable amino acid sequence similarity among family members particularly in the ATP binding site. Targeting the activation loop might offer improved inhibitor selectivity since this region of kinases is less conserved. However, the strategy presents difficulties due to activation loop flexibility. Herein, we report the design of receptor-interacting protein kinase 2 (RIPK2) inhibitors based on pan-kinase inhibitor regorafenib that aim to engage basic activation loop residues Lys169 or Arg171. We report development of CSR35 that displayed >10-fold selective inhibition of RIPK2 versus VEGFR2, the target of regorafenib. A co-crystal structure of CSR35 with RIPK2 revealed a resolved activation loop with an ionic interaction between the carboxylic acid installed in the inhibitor and the side-chain of Lys169. Our data provides principle feasibility of developing activation loop targeting type II inhibitors as a complementary strategy for achieving improved selectivity. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Photodynamic therapy for inactivating endodontic bacterial biofilms and effect of tissue inhibitors on antibacterial efficacy

NASA Astrophysics Data System (ADS)

Shrestha, Annie; Kishen, Anil

Complex nature of bacterial cell membrane and structure of biofilm has challenged the efficacy of antimicrobial photodynamic therapy (APDT) to achieve effective disinfection of infected root canals. In addition, tissue-inhibitors present inside the root canals are known to affect APDT activity. This study was aimed to assess the effect of APDT on bacterial biofilms and evaluate the effect of tissue-inhibitors on the APDT. Rose-bengal (RB) and methylene-blue (MB) were tested on Enterococcus faecalis (gram-positive) and Pseudomonas aeruginosa (gram-negative) biofilms. In vitro 7- day old biofilms were sensitized with RB and MB, and photodynamically activated with 20-60 J/cm2. Photosensitizers were pre-treated with different tissue-inhibitors (dentin, dentin-matrix, pulp tissue, bacterial lipopolysaccharides (LPS), and bovine serum albumin (BSA)) and tested for antibacterial effect of APDT. Microbiological culture based analysis was used to analyze the cell viability, while Laser Scanning Confocal Microscopy (LSCM) was used to examine the structure of biofilm. Photoactivation resulted in significant reduction of bacterial biofilms with RB and MB. The structure of biofilm under LSCM was found to be disrupted with reduced biofilm thickness. Complete biofilm elimination could not be achieved with both tested photosensitizers. APDT effect using MB and RB was inhibited in a decreasing order by dentin-matrix, BSA, pulp, dentin and LPS (P< 0.05). Both strains of bacterial biofilms resisted complete elimination after APDT and the tissue inhibitors existing within the root canal reduced the antibacterial activity at varying degrees. Further research is required to enhance the antibacterial efficacy of APDT in an endodontic environment.

Curation of inhibitor-target data: process and impact on pathway analysis.

PubMed

Devidas, Sreenivas

2009-01-01

The past decade has seen a significant emergence in the availability and use of pathway analysis tools. The workflow that is supported by most of the pathway analysis tools is limited to either of the following: a. a network of genes based on the input data set, or b. the resultant network filtered down by a few criteria such as (but not limited to) i. disease association of the genes in the network; ii. targets known to be the target of one or more launched drugs; iii. targets known to be the target of one or more compounds in clinical trials; and iv. targets reasonably known to be potential candidate or clinical biomarkers. Almost all the tools in use today are biased towards the biological side and contain little, if any, information on the chemical inhibitors associated with the components of a given biological network. The limitation resides as follows: The fact that the number of inhibitors that have been published or patented is probably several fold (probably greater than 10-fold) more than the number of published protein-protein interactions. Curation of such data is both expensive and time consuming and could impact ROI significantly. The non-standardization associated with protein and gene names makes mapping reasonably non-straightforward. The number of patented and published inhibitors across target classes increases by over a million per year. Therefore, keeping the databases current becomes a monumental problem. Modifications required in the product architectures to accommodate chemistry-related content. GVK Bio has, over the past 7 years, curated the compound-target data that is necessary for the addition of such compound-centric workflows. This chapter focuses on identification, curation and utility of such data.

Analysis of Tyrosine Kinase Inhibitor-Mediated Decline in Contractile Force in Rat Engineered Heart Tissue.

PubMed

Jacob, Fabian; Yonis, Amina Y; Cuello, Friederike; Luther, Pradeep; Schulze, Thomas; Eder, Alexandra; Streichert, Thomas; Mannhardt, Ingra; Hirt, Marc N; Schaaf, Sebastian; Stenzig, Justus; Force, Thomas; Eschenhagen, Thomas; Hansen, Arne

2016-01-01

Left ventricular dysfunction is a frequent and potentially severe side effect of many tyrosine kinase inhibitors (TKI). The mode of toxicity is not identified, but may include impairment of mitochondrial or sarcomeric function, autophagy or angiogenesis, either as an on-target or off-target mechanism. We studied concentration-response curves and time courses for nine TKIs in three-dimensional, force generating engineered heart tissue (EHT) from neonatal rat heart cells. We detected a concentration- and time-dependent decline in contractile force for gefitinib, lapatinib, sunitinib, imatinib, sorafenib, vandetanib and lestaurtinib and no decline in contractile force for erlotinib and dasatinib after 96 hours of incubation. The decline in contractile force was associated with an impairment of autophagy (LC3 Western blot) and appearance of autophagolysosomes (transmission electron microscopy). This study demonstrates the feasibility to study TKI-mediated force effects in EHTs and identifies an association between a decline in contractility and inhibition of autophagic flux.

Analysis of Tyrosine Kinase Inhibitor-Mediated Decline in Contractile Force in Rat Engineered Heart Tissue

PubMed Central

Cuello, Friederike; Luther, Pradeep; Schulze, Thomas; Eder, Alexandra; Streichert, Thomas; Mannhardt, Ingra; Hirt, Marc N.; Schaaf, Sebastian; Stenzig, Justus; Force, Thomas

2016-01-01

Introduction Left ventricular dysfunction is a frequent and potentially severe side effect of many tyrosine kinase inhibitors (TKI). The mode of toxicity is not identified, but may include impairment of mitochondrial or sarcomeric function, autophagy or angiogenesis, either as an on-target or off-target mechanism. Methods and Results We studied concentration-response curves and time courses for nine TKIs in three-dimensional, force generating engineered heart tissue (EHT) from neonatal rat heart cells. We detected a concentration- and time-dependent decline in contractile force for gefitinib, lapatinib, sunitinib, imatinib, sorafenib, vandetanib and lestaurtinib and no decline in contractile force for erlotinib and dasatinib after 96 hours of incubation. The decline in contractile force was associated with an impairment of autophagy (LC3 Western blot) and appearance of autophagolysosomes (transmission electron microscopy). Conclusion This study demonstrates the feasibility to study TKI-mediated force effects in EHTs and identifies an association between a decline in contractility and inhibition of autophagic flux. PMID:26840448

Epithelial tissue hyperplasia induced by the RAF inhibitor PF-04880594 is attenuated by a clinically well-tolerated dose of the MEK inhibitor PD-0325901.

PubMed

Torti, Vince R; Wojciechowicz, Donald; Hu, Wenyue; John-Baptiste, Annette; Evering, Winston; Troche, Gabriel; Marroquin, Lisa D; Smeal, Tod; Yamazaki, Shinji; Palmer, Cynthia L; Burns-Naas, Leigh Ann; Bagrodia, Shubha

2012-10-01

Clinical trials of selective RAF inhibitors in patients with melanoma tumors harboring activated BRAFV600E have produced very promising results, and a RAF inhibitor has been approved for treatment of advanced melanoma. However, about a third of patients developed resectable skin tumors during the course of trials. This is likely related to observations that RAF inhibitors activate extracellular signal-regulated kinase (ERK) signaling, stimulate proliferation, and induce epithelial hyperplasia in preclinical models. Because these findings raise safety concerns about RAF inhibitor development, we further investigated the underlying mechanisms. We showed that the RAF inhibitor PF-04880594 induces ERK phosphorylation and RAF dimerization in those epithelial tissues that undergo hyperplasia. Hyperplasia and ERK hyperphosphorylation are prevented by treatment with the mitogen-activated protein/extracellular signal-regulated kinase (MEK) inhibitor PD-0325901 at exposures that extrapolate to clinically well-tolerated doses. To facilitate mechanistic and toxicologic studies, we developed a three-dimensional cell culture model of epithelial layering that recapitulated the RAF inhibitor-induced hyperplasia and reversal by MEK inhibitor in vitro. We also showed that PF-04880594 stimulates production of the inflammatory cytokine interleukin 8 in HL-60 cells, suggesting a possible mechanism for the skin flushing observed in dogs. The complete inhibition of hyperplasia by MEK inhibitor in epithelial tissues does not seem to reduce RAF inhibitor efficacy and, in fact, allows doubling of the PF-04880594 dose without toxicity usually associated with such doses. These findings indicated that combination treatment with MEK inhibitors might greatly increase the safety and therapeutic index of RAF inhibitors for the treatment of melanoma and other cancers. ©2012 AACR.

Discovery of host-targeted covalent inhibitors of dengue virus

PubMed Central

de Wispelaere, Mélissanne; Carocci, Margot; Liang, Yanke; Liu, Qingsong; Sun, Eileen; Vetter, Michael L.; Wang, Jinhua; Gray, Nathanael S.; Yang, Priscilla L.

2017-01-01

We report here on an approach targeting the host reactive cysteinome to identify inhibitors of host factors required for the infectious cycle of Flaviviruses and other viruses. We used two parallel cellular phenotypic screens to identify a series of covalent inhibitors, exemplified by QL-XII-47, that are active against dengue virus. We show that the compounds effectively block viral protein expression and that this inhibition is associated with repression of downstream processes of the infectious cycle, and thus significantly contributes to the potent antiviral activity of these compounds. We demonstrate that QL-XII-47’s antiviral activity requires selective, covalent modification of a host target by showing that the compound's antiviral activity is recapitulated when cells are preincubated with QL-XII-47 and then washed prior to viral infection and by showing that QL-XII-47R, a non-reactive analog, lacks antiviral activity at concentrations more than 20-fold higher than QL-XII-47's IC90. QL-XII-47’s inhibition of Zika virus, West Nile virus, hepatitis C virus, and poliovirus further suggests that it acts via a target mediating inhibition of these other medically relevant viruses. These results demonstrate the utility of screens targeting the host reactive cysteinome for rapid identification of compounds with potent antiviral activity. PMID:28034743

Suramin Inhibits Osteoarthritic Cartilage Degradation by Increasing Extracellular Levels of Chondroprotective Tissue Inhibitor of Metalloproteinases 3.

PubMed

Chanalaris, Anastasios; Doherty, Christine; Marsden, Brian D; Bambridge, Gabriel; Wren, Stephen P; Nagase, Hideaki; Troeberg, Linda

2017-10-01

Osteoarthritis is a common degenerative joint disease for which no disease-modifying drugs are currently available. Attempts to treat the disease with small molecule inhibitors of the metalloproteinases that degrade the cartilage matrix have been hampered by a lack of specificity. We aimed to inhibit cartilage degradation by augmenting levels of the endogenous metalloproteinase inhibitor, tissue inhibitor of metalloproteinases (TIMP)-3, through blocking its interaction with the endocytic scavenger receptor, low-density lipoprotein receptor-related protein 1 (LRP1). We discovered that suramin (C 51 H 40 N 6 O 23 S 6 ) bound to TIMP-3 with a K D value of 1.9 ± 0.2 nM and inhibited its endocytosis via LRP1, thus increasing extracellular levels of TIMP-3 and inhibiting cartilage degradation by the TIMP-3 target enzyme, adamalysin-like metalloproteinase with thrombospondin motifs 5. NF279 (8,8'-[carbonyl bis (imino-4,1-phenylenecarbonylimino-4,1-phenylenecarbonylimino)] bis -1,3,5-naphthalenetrisulfonic acid hexasodium salt), a structural analog of suramin, has an increased affinity for TIMP-3 and increased ability to inhibit TIMP-3 endocytosis and protect cartilage. Suramin is thus a promising scaffold for the development of novel therapeutics to increase TIMP-3 levels and inhibit cartilage degradation in osteoarthritis. Copyright © 2017 by The Author(s).

Selective inhibitors of zinc-dependent histone deacetylases. Therapeutic targets relevant to cancer.

PubMed

Kollar, Jakub; Frecer, Vladimir

2015-01-01

Histone deacetylases (HDACs), which act on acetylated histones and/or other non-histone protein substrates, represent validated epigenetic targets for the treatment of cancer and other human diseases. The inhibition of HDAC activity was shown to induce cell cycle arrest, differentiation, apoptosis as well as a decrease in proliferation, angiogenesis, migration, and cell resistance to chemotherapy. Targeting single HDAC isoforms with selective inhibitors will help to reveal the role of individual HDACs in cancer development or uncover further biological consequences of protein acetylation. This review focuses on conventional zinc-containing HDACs. In its first part, the biological role of individual HDACs in various types of cancer is summarized. In the second part, promising HDAC inhibitors showing activity both in enzymatic and cell-based assays are surveyed with an emphasis on the inhibitors selective to the individual HDACs.

Targeting Btk/Etk of prostate cancer cells by a novel dual inhibitor

PubMed Central

Guo, W; Liu, R; Bhardwaj, G; Yang, J C; Changou, C; Ma, A-H; Mazloom, A; Chintapalli, S; Xiao, K; Xiao, W; Kumaresan, P; Sanchez, E; Yeh, C-T; Evans, C P; Patterson, R; Lam, K S; Kung, H-J

2014-01-01

Btk and Etk/BMX are Tec-family non-receptor tyrosine kinases. Btk has previously been reported to be expressed primarily in B cells and has an important role in immune responses and B-cell malignancies. Etk has been shown previously to provide a strong survival and metastasis signal in human prostate cancer cells, and to confer androgen independence and drug resistance. While the role of Etk in prostate carcinogenesis is well established, the functions of Btk in prostate cancer have never been investigated, likely due to the perception that Btk is a hematopoietic, but not epithelial, kinase. Herein, we found that Btk is overexpressed in prostate cancer tissues and prostate cancer cells. The level of Btk in prostate cancer tissues correlates with cancer grades. Knockdown of Btk expression selectively inhibits the growth of prostate cancer cells, but not that of the normal prostate epithelial cells, which express very little Btk. Dual inhibition of Btk and Etk has an additive inhibitory effect on prostate cancer cell growth. To explore Btk and Etk as targets for prostate cancer, we developed a small molecule dual inhibitor of Btk and Etk, CTN06. Treatment of PC3 and other prostate cancer cells, but not immortalized prostate epithelial cells with CTN06 resulted in effective cell killing, accompanied by the attenuation of Btk/Etk signals. The killing effect of CTN06 is more potent than that of commonly used inhibitors against Src, Raf/VEGFR and EGFR. CTN06 induces apoptosis as well as autophagy in human prostate cancer cells, and is a chemo-sensitizer for docetaxel (DTX), a standard of care for metastatic prostate cancer patients. CTN06 also impeded the migration of human prostate cancer cells based on a ‘wound healing' assay. The anti-cancer effect of CTN06 was further validated in vivo in a PC3 xenograft mouse model. PMID:25188519

Targeting Btk/Etk of prostate cancer cells by a novel dual inhibitor.

PubMed

Guo, W; Liu, R; Bhardwaj, G; Yang, J C; Changou, C; Ma, A-H; Mazloom, A; Chintapalli, S; Xiao, K; Xiao, W; Kumaresan, P; Sanchez, E; Yeh, C-T; Evans, C P; Patterson, R; Lam, K S; Kung, H-J

2014-09-04

Btk and Etk/BMX are Tec-family non-receptor tyrosine kinases. Btk has previously been reported to be expressed primarily in B cells and has an important role in immune responses and B-cell malignancies. Etk has been shown previously to provide a strong survival and metastasis signal in human prostate cancer cells, and to confer androgen independence and drug resistance. While the role of Etk in prostate carcinogenesis is well established, the functions of Btk in prostate cancer have never been investigated, likely due to the perception that Btk is a hematopoietic, but not epithelial, kinase. Herein, we found that Btk is overexpressed in prostate cancer tissues and prostate cancer cells. The level of Btk in prostate cancer tissues correlates with cancer grades. Knockdown of Btk expression selectively inhibits the growth of prostate cancer cells, but not that of the normal prostate epithelial cells, which express very little Btk. Dual inhibition of Btk and Etk has an additive inhibitory effect on prostate cancer cell growth. To explore Btk and Etk as targets for prostate cancer, we developed a small molecule dual inhibitor of Btk and Etk, CTN06. Treatment of PC3 and other prostate cancer cells, but not immortalized prostate epithelial cells with CTN06 resulted in effective cell killing, accompanied by the attenuation of Btk/Etk signals. The killing effect of CTN06 is more potent than that of commonly used inhibitors against Src, Raf/VEGFR and EGFR. CTN06 induces apoptosis as well as autophagy in human prostate cancer cells, and is a chemo-sensitizer for docetaxel (DTX), a standard of care for metastatic prostate cancer patients. CTN06 also impeded the migration of human prostate cancer cells based on a 'wound healing' assay. The anti-cancer effect of CTN06 was further validated in vivo in a PC3 xenograft mouse model.

Target and Tissue Selectivity Prediction by Integrated Mechanistic Pharmacokinetic-Target Binding and Quantitative Structure Activity Modeling.

PubMed

Vlot, Anna H C; de Witte, Wilhelmus E A; Danhof, Meindert; van der Graaf, Piet H; van Westen, Gerard J P; de Lange, Elizabeth C M

2017-12-04

Selectivity is an important attribute of effective and safe drugs, and prediction of in vivo target and tissue selectivity would likely improve drug development success rates. However, a lack of understanding of the underlying (pharmacological) mechanisms and availability of directly applicable predictive methods complicates the prediction of selectivity. We explore the value of combining physiologically based pharmacokinetic (PBPK) modeling with quantitative structure-activity relationship (QSAR) modeling to predict the influence of the target dissociation constant (K D ) and the target dissociation rate constant on target and tissue selectivity. The K D values of CB1 ligands in the ChEMBL database are predicted by QSAR random forest (RF) modeling for the CB1 receptor and known off-targets (TRPV1, mGlu5, 5-HT1a). Of these CB1 ligands, rimonabant, CP-55940, and Δ 8 -tetrahydrocanabinol, one of the active ingredients of cannabis, were selected for simulations of target occupancy for CB1, TRPV1, mGlu5, and 5-HT1a in three brain regions, to illustrate the principles of the combined PBPK-QSAR modeling. Our combined PBPK and target binding modeling demonstrated that the optimal values of the K D and k off for target and tissue selectivity were dependent on target concentration and tissue distribution kinetics. Interestingly, if the target concentration is high and the perfusion of the target site is low, the optimal K D value is often not the lowest K D value, suggesting that optimization towards high drug-target affinity can decrease the benefit-risk ratio. The presented integrative structure-pharmacokinetic-pharmacodynamic modeling provides an improved understanding of tissue and target selectivity.

Small-molecule inhibitors of the receptor tyrosine kinases: promising tools for targeted cancer therapies.

PubMed

Hojjat-Farsangi, Mohammad

2014-08-08

Chemotherapeutic and cytotoxic drugs are widely used in the treatment of cancer. In spite of the improvements in the life quality of patients, their effectiveness is compromised by several disadvantages. This represents a demand for developing new effective strategies with focusing on tumor cells and minimum side effects. Targeted cancer therapies and personalized medicine have been defined as a new type of emerging treatments. Small molecule inhibitors (SMIs) are among the most effective drugs for targeted cancer therapy. The growing number of approved SMIs of receptor tyrosine kinases (RTKs) i.e., tyrosine kinase inhibitors (TKIs) in the clinical oncology imply the increasing attention and application of these therapeutic tools. Most of the current approved RTK-TKIs in preclinical and clinical settings are multi-targeted inhibitors with several side effects. Only a few specific/selective RTK-TKIs have been developed for the treatment of cancer patients. Specific/selective RTK-TKIs have shown less deleterious effects compared to multi-targeted inhibitors. This review intends to highlight the importance of specific/selective TKIs for future development with less side effects and more manageable agents. This article provides an overview of: (1) the characteristics and function of RTKs and TKIs; (2) the recent advances in the improvement of specific/selective RTK-TKIs in preclinical or clinical settings; and (3) emerging RTKs for targeted cancer therapies by TKIs.

Compound Selectivity and Target Residence Time of Kinase Inhibitors Studied with Surface Plasmon Resonance.

PubMed

Willemsen-Seegers, Nicole; Uitdehaag, Joost C M; Prinsen, Martine B W; de Vetter, Judith R F; de Man, Jos; Sawa, Masaaki; Kawase, Yusuke; Buijsman, Rogier C; Zaman, Guido J R

2017-02-17

Target residence time (τ) has been suggested to be a better predictor of the biological activity of kinase inhibitors than inhibitory potency (IC 50 ) in enzyme assays. Surface plasmon resonance binding assays for 46 human protein and lipid kinases were developed. The association and dissociation constants of 80 kinase inhibitor interactions were determined. τ and equilibrium affinity constants (K D ) were calculated to determine kinetic selectivity. Comparison of τ and K D or IC 50 values revealed a strikingly different view on the selectivity of several kinase inhibitors, including the multi-kinase inhibitor ponatinib, which was tested on 10 different kinases. In addition, known pan-Aurora inhibitors resided much longer on Aurora B than on Aurora A, despite having comparable affinity for Aurora A and B. Furthermore, the γ/δ-selective PI3K inhibitor duvelisib and the δ-selective drug idelalisib had similar 20-fold selectivity for δ- over γ-isoform but duvelisib resided much longer on both targets. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of a 3D Tissue Culture-Based High-Content Screening Platform That Uses Phenotypic Profiling to Discriminate Selective Inhibitors of Receptor Tyrosine Kinases.

PubMed

Booij, Tijmen H; Klop, Maarten J D; Yan, Kuan; Szántai-Kis, Csaba; Szokol, Balint; Orfi, Laszlo; van de Water, Bob; Keri, Gyorgy; Price, Leo S

2016-10-01

3D tissue cultures provide a more physiologically relevant context for the screening of compounds, compared with 2D cell cultures. Cells cultured in 3D hydrogels also show complex phenotypes, increasing the scope for phenotypic profiling. Here we describe a high-content screening platform that uses invasive human prostate cancer cells cultured in 3D in standard 384-well assay plates to study the activity of potential therapeutic small molecules and antibody biologics. Image analysis tools were developed to process 3D image data to measure over 800 phenotypic parameters. Multiparametric analysis was used to evaluate the effect of compounds on tissue morphology. We applied this screening platform to measure the activity and selectivity of inhibitors of the c-Met and epidermal growth factor (EGF) receptor (EGFR) tyrosine kinases in 3D cultured prostate carcinoma cells. c-Met and EGFR activity was quantified based on the phenotypic profiles induced by their respective ligands, hepatocyte growth factor and EGF. The screening method was applied to a novel collection of 80 putative inhibitors of c-Met and EGFR. Compounds were identified that induced phenotypic profiles indicative of selective inhibition of c-Met, EGFR, or bispecific inhibition of both targets. In conclusion, we describe a fully scalable high-content screening platform that uses phenotypic profiling to discriminate selective and nonselective (off-target) inhibitors in a physiologically relevant 3D cell culture setting. © 2016 Society for Laboratory Automation and Screening.

Structure-based design of pteridine reductase inhibitors targeting African sleeping sickness and the leishmaniases.

PubMed

Tulloch, Lindsay B; Martini, Viviane P; Iulek, Jorge; Huggan, Judith K; Lee, Jeong Hwan; Gibson, Colin L; Smith, Terry K; Suckling, Colin J; Hunter, William N

2010-01-14

Pteridine reductase (PTR1) is a target for drug development against Trypanosoma and Leishmania species, parasites that cause serious tropical diseases and for which therapies are inadequate. We adopted a structure-based approach to the design of novel PTR1 inhibitors based on three molecular scaffolds. A series of compounds, most newly synthesized, were identified as inhibitors with PTR1-species specific properties explained by structural differences between the T. brucei and L. major enzymes. The most potent inhibitors target T. brucei PTR1, and two compounds displayed antiparasite activity against the bloodstream form of the parasite. PTR1 contributes to antifolate drug resistance by providing a molecular bypass of dihydrofolate reductase (DHFR) inhibition. Therefore, combining PTR1 and DHFR inhibitors might improve therapeutic efficacy. We tested two new compounds with known DHFR inhibitors. A synergistic effect was observed for one particular combination highlighting the potential of such an approach for treatment of African sleeping sickness.

Target Residence Time-Guided Optimization on TTK Kinase Results in Inhibitors with Potent Anti-Proliferative Activity.

PubMed

Uitdehaag, Joost C M; de Man, Jos; Willemsen-Seegers, Nicole; Prinsen, Martine B W; Libouban, Marion A A; Sterrenburg, Jan Gerard; de Wit, Joeri J P; de Vetter, Judith R F; de Roos, Jeroen A D M; Buijsman, Rogier C; Zaman, Guido J R

2017-07-07

The protein kinase threonine tyrosine kinase (TTK; also known as Mps1) is a critical component of the spindle assembly checkpoint and a promising drug target for the treatment of aggressive cancers, such as triple negative breast cancer. While the first TTK inhibitors have entered clinical trials, little is known about how the inhibition of TTK with small-molecule compounds affects cellular activity. We studied the selective TTK inhibitor NTRC 0066-0, which was developed in our own laboratory, together with 11 TTK inhibitors developed by other companies, including Mps-BAY2b, BAY 1161909, BAY 1217389 (Bayer), TC-Mps1-12 (Shionogi), and MPI-0479605 (Myrexis). Parallel testing shows that the cellular activity of these TTK inhibitors correlates with their binding affinity to TTK and, more strongly, with target residence time. TTK inhibitors are therefore an example where target residence time determines activity in in vitro cellular assays. X-ray structures and thermal stability experiments reveal that the most potent compounds induce a shift of the glycine-rich loop as a result of binding to the catalytic lysine at position 553. This "lysine trap" disrupts the catalytic machinery. Based on these insights, we developed TTK inhibitors, based on a (5,6-dihydro)pyrimido[4,5-e]indolizine scaffold, with longer target residence times, which further exploit an allosteric pocket surrounding Lys553. Their binding mode is new for kinase inhibitors and can be classified as hybrid Type I/Type III. These inhibitors have very potent anti-proliferative activity that rivals classic cytotoxic therapy. Our findings will open up new avenues for more applications for TTK inhibitors in cancer treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydroxybenzoic Acid Derivatives as Dual-Target Ligands: Mitochondriotropic Antioxidants and Cholinesterase Inhibitors.

PubMed

Oliveira, Catarina; Cagide, Fernando; Teixeira, José; Amorim, Ricardo; Sequeira, Lisa; Mesiti, Francesco; Silva, Tiago; Garrido, Jorge; Remião, Fernando; Vilar, Santiago; Uriarte, Eugenio; Oliveira, Paulo J; Borges, Fernanda

2018-01-01

Alzheimer's disease (AD) is a multifactorial age-related disease associated with oxidative stress (OS) and impaired cholinergic transmission. Accordingly, targeting mitochondrial OS and restoring cholinergic transmission can be an effective therapeutic strategy toward AD. Herein, we report for the first time dual-target hydroxybenzoic acid (HBAc) derivatives acting as mitochondriotropic antioxidants and cholinesterase (ChE) inhibitors. The studies were performed with two mitochondriotropic antioxidants AntiOxBEN 1 (catechol derivative), and AntiOxBEN 2 (pyrogallol derivative) and compounds 15-18 , which have longer spacers. Compounds AntiOxBEN 1 and 15 , with a shorter carbon chain spacer (six- and eight-carbon) were shown to be potent antioxidants and BChE inhibitors (IC 50 = 85 ± 5 and 106 ± 5 nM, respectively), while compounds 17 and 18 with a 10-carbon chain were more effective AChE inhibitors (IC 50 = 7.7 ± 0.4 and 7.2 ± 0.5 μM, respectively). Interestingly, molecular modeling data pointed toward bifunctional ChEs inhibitors. The most promising ChE inhibitors acted by a non-competitive mechanism. In general, with exception of compounds 15 and 17 , no cytotoxic effects were observed in differentiated human neuroblastoma (SH-SY5Y) and human hepatocarcinoma (HepG2) cells, while Aβ-induced cytotoxicity was significantly prevented by the new dual-target HBAc derivatives. Overall, due to its BChE selectivity, favorable toxicological profile, neuroprotective activity and drug-like properties, which suggested blood-brain barrier (BBB) permeability, the mitochondriotropic antioxidant AntiOxBEN 1 is considered a valid lead candidate for the development of dual acting drugs for AD and other mitochondrial OS-related diseases.

Hydroxybenzoic Acid Derivatives as Dual-Target Ligands: Mitochondriotropic Antioxidants and Cholinesterase Inhibitors

PubMed Central

Oliveira, Catarina; Cagide, Fernando; Teixeira, José; Amorim, Ricardo; Sequeira, Lisa; Mesiti, Francesco; Silva, Tiago; Garrido, Jorge; Remião, Fernando; Vilar, Santiago; Uriarte, Eugenio; Oliveira, Paulo J.; Borges, Fernanda

2018-01-01

Alzheimer's disease (AD) is a multifactorial age-related disease associated with oxidative stress (OS) and impaired cholinergic transmission. Accordingly, targeting mitochondrial OS and restoring cholinergic transmission can be an effective therapeutic strategy toward AD. Herein, we report for the first time dual-target hydroxybenzoic acid (HBAc) derivatives acting as mitochondriotropic antioxidants and cholinesterase (ChE) inhibitors. The studies were performed with two mitochondriotropic antioxidants AntiOxBEN1 (catechol derivative), and AntiOxBEN2 (pyrogallol derivative) and compounds 15–18, which have longer spacers. Compounds AntiOxBEN1 and 15, with a shorter carbon chain spacer (six- and eight-carbon) were shown to be potent antioxidants and BChE inhibitors (IC50 = 85 ± 5 and 106 ± 5 nM, respectively), while compounds 17 and 18 with a 10-carbon chain were more effective AChE inhibitors (IC50 = 7.7 ± 0.4 and 7.2 ± 0.5 μM, respectively). Interestingly, molecular modeling data pointed toward bifunctional ChEs inhibitors. The most promising ChE inhibitors acted by a non-competitive mechanism. In general, with exception of compounds 15 and 17, no cytotoxic effects were observed in differentiated human neuroblastoma (SH-SY5Y) and human hepatocarcinoma (HepG2) cells, while Aβ-induced cytotoxicity was significantly prevented by the new dual-target HBAc derivatives. Overall, due to its BChE selectivity, favorable toxicological profile, neuroprotective activity and drug-like properties, which suggested blood-brain barrier (BBB) permeability, the mitochondriotropic antioxidant AntiOxBEN1 is considered a valid lead candidate for the development of dual acting drugs for AD and other mitochondrial OS-related diseases. PMID:29740575

Hydroxybenzoic acid derivatives as dual-target ligands: mitochondriotropic antioxidants and cholinesterase inhibitors

NASA Astrophysics Data System (ADS)

Oliveira, Catarina; Cagide, Fernando; Teixeira, José; Amorim, Ricardo; Sequeira, Lisa; Mesiti, Francesco; Silva, Tiago; Garrido, Jorge; Remião, Fernando; Vilar, Santiago; Uriarte, Eugenio; Oliveira, Paulo J.; Borges, Fernanda

2018-04-01

Alzheimer’s disease (AD) is a multifactorial age-related disease associated with oxidative stress (OS) and impaired cholinergic transmission. Accordingly, targeting mitochondrial OS and restoring cholinergic transmission can be an effective therapeutic strategy towards AD. Herein, we report for the first time dual-target hydroxybenzoic acid (HBAc) derivatives acting as mitochondriotropic antioxidants and cholinesterase (ChE) inhibitors. The studies were performed with two mitochondriotropic antioxidants AntiOxBEN1 (catechol derivative), and AntiOxBEN2 (pyrogallol derivative) and compounds 15-18, which have longer spacers. Compounds AntiOxBEN1 and 15, with a shorter carbon chain spacer (six- and eight-carbon) were shown to be potent antioxidants and BChE inhibitors (IC50 = 85 ± 5 and 106 ± 5 nM, respectively), while compounds 17 and 18 with a ten-carbon chain were more effective AChE inhibitors (IC50 = 7.7 ± 0.4 and 7.2 ± 0.5 nM, respectively). Interestingly, molecular modelling data pointed towards bifunctional ChEs inhibitors. The most promising ChE inhibitors acted by a non-competitive mechanism. In general, with exception of compounds 15 and 17, no cytotoxic effects were observed in differentiated human neuroblastoma (SH-SY5Y) and human hepatocarcinoma (HepG2) cells, while Αβ-induced cytotoxicity was significantly prevented by the new dual-target HBAc derivatives. Overall, due to its BChE selectivity, favourable toxicological profile, neuroprotective activity and drug-like properties, which suggested blood-brain barrier (BBB) permeability, the mitochondriotropic antioxidant AntiOxBEN1 is considered a valid lead candidate for the development of dual acting drugs for AD and other mitochondrial OS-related disease

A possible usage of a CDK4 inhibitor for breast cancer stem cell-targeted therapy

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

Han, Yu Kyeong; Lee, Jae Ho; Park, Ga-Young

2013-01-25

Highlights: ► A CDK4 inhibitor may be used for breast cancer stem cell-targeted therapy. ► The CDK4 inhibitor differentiated the cancer stem cell population (CD24{sup −}/CD44{sup +}) of MDA-MB-231. ► The differentiation of the cancer stem cells by the CDK4 inhibitor radiosensitized MDA-MB-231. -- Abstract: Cancer stem cells (CSCs) are one of the main reasons behind cancer recurrence due to their resistance to conventional anti-cancer therapies. Thus, many efforts are being devoted to developing CSC-targeted therapies to overcome the resistance of CSCs to conventional anti-cancer therapies and decrease cancer recurrence. Differentiation therapy is one potential approach to achieve CSC-targeted therapies.more » This method involves inducing immature cancer cells with stem cell characteristics into more mature or differentiated cancer cells. In this study, we found that a CDK4 inhibitor sensitized MDA-MB-231 cells but not MCF7 cells to irradiation. This difference appeared to be associated with the relative percentage of CSC-population between the two breast cancer cells. The CDK4 inhibitor induced differentiation and reduced the cancer stem cell activity of MDA-MB-231 cells, which are shown by multiple marker or phenotypes of CSCs. Thus, these results suggest that radiosensitization effects may be caused by reducing the CSC-population of MDA-MB-231 through the use of the CDK4 inhibitor. Thus, further investigations into the possible application of the CDK4 inhibitor for CSC-targeted therapy should be performed to enhance the efficacy of radiotherapy for breast cancer.« less

The tissue inhibitors of metalloproteinases (TIMPs): An ancient family with structural and functional diversity

PubMed Central

Brew, Keith; Nagase, Hideaki

2010-01-01

Tissue inhibitors of metalloproteinases (TIMPs) are widely distributed in the animal kingdom and the human genome contains four paralogous genes encoding TIMPs 1 to 4. TIMPs were originally characterized as inhibitors of matrix metalloproteinases (MMPs), but their range of activities has now been found to be broader as it includes the inhibition of several of the disintegrin-metalloproteinases, ADAMs and ADAMTSs. TIMPs are therefore key regulators of the metalloproteinases that degrade the extracellular matrix and shed cell surface molecules. Structural studies of TIMP–MMP complexes have elucidated the inhibition mechanism of TIMPs and the multiple sites through which they interact with target enzymes, allowing the generation of TIMP variants that selectively inhibit different groups of metalloproteinases. Engineering such variants is complicated by the fact that TIMPs can undergo changes in molecular dynamics induced by their interactions with proteases. TIMPs also have biological activities that are independent of metalloproteinases; these include effects on cell growth and differentiation, cell migration, anti-angiogenesis, anti- and pro-apoptosis, and synaptic plasticity. Receptors responsible for some of these activities have been identified and their signaling pathways have been investigated. A series of studies using mice with specific TIMP gene deletions has illuminated the importance of these molecules in biology and pathology. PMID:20080133

Dual targeting DNA gyrase B (GyrB) and topoisomerse IV (ParE) inhibitors: A review.

PubMed

Azam, Mohammed Afzal; Thathan, Janarthanan; Jubie, Selvaraj

2015-10-01

GyrB and ParE are type IIA topoisomerases and found in most bacteria. Its function is vital for DNA replication, repair and decatenation. The highly conserved ATP-binding subunits of DNA GyrB and ParE are structurally related and have been recognized as prime candidates for the development of dual-targeting antibacterial agents with broad-spectrum potential. However, no natural product or small molecule inhibitors targeting ATPase catalytic domain of both GyrB and ParE enzymes have succeeded in the clinic. Moreover, no inhibitors of these enzymes with broad-spectrum antibacterial activity against Gram-negative pathogens have been reported. Availability of high resolution crystal structures of GyrB and ParE made it possible for the design of many different classes of inhibitors with dual mechanism of action. Among them benzimidazoles, benzothiazoles, thiazolopyridines, imidiazopyridazoles, pyridines, indazoles, pyrazoles, imidazopyridines, triazolopyridines, pyrrolopyrimidines, pyrimidoindoles as well as related structures are disclosed in literatures. Unfortunately most of these inhibitors are found to be active against Gram-positive pathogens. In the present review we discuss about studies on novel dual targeting ATPase inhibitors. Copyright © 2015 Elsevier Inc. All rights reserved.

Preliminary in vitro and in vivo assessment of a new targeted inhibitor for choroidal neovascularization in age-related macular degeneration.

PubMed

Li, Wenbo; Dong, Lijie; Ma, Minwang; Hu, Bojie; Lu, Zhenyu; Liu, Xun; Liu, Juping; Li, Xiaorong

2016-01-01

Choroidal neovascularization (CNV) in age-related macular degeneration usually causes blindness. We established a novel targeted inhibitor for CNV in age-related macular degeneration. The inhibitor CR2-sFlt 1 comprises a CR2-targeting fragment and an anti-vascular endothelial growth factor (VEGF) domain (sFlt 1). The targeting of CR2-sFlt 1 was studied using the transwell assay in vitro and frozen sections in vivo using green fluorescent labeling. Transwell assay results showed that CR2-sFlt 1 migrated to the interface of complement activation products and was present in the retinal tissue of the CR2-sFlt 1-treated CNV mice. Treatment effects were assessed by investigating the VEGF concentration in retinal pigmented epithelial cell medium and the thickness of the CNV complex in the mice treated with CR2-sFlt 1. CR2-sFlt 1 significantly reduced the VEGF secretion from retinal pigmented epithelial cells in vitro and retarded CNV progress in a mouse model. Expression analysis of VEGF and VEGFRs after CR2-sFlt 1 intervention indicated the existence of feedback mechanisms in exogenous CR2-sFlt 1, endogenous VEGF, and VEGFR interaction. In summary, we demonstrated for the first time that using CR2-sFlt 1 could inhibit CNV with clear targeting and high selectivity.

Heterogeneous effects of tissue inhibitors of matrix metalloproteinases on cardiac fibroblasts.

PubMed

Lovelock, Joshua D; Baker, Andrew H; Gao, Feng; Dong, Jing-Fei; Bergeron, Angela L; McPheat, Willie; Sivasubramanian, Natarajan; Mann, Douglas L

2005-02-01

The balance between matrix metalloproteinases (MMPs) and their natural inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), plays a critical role in cardiac remodeling. Although a number of studies have characterized the pathophysiological role of MMPs in the heart, very little is known with respect to the role of TIMPs in the heart. To delineate the role of TIMPs in the heart we examined the effects of adenovirus-mediated overexpression of TIMP-1, -2, -3, and -4 in cardiac fibroblasts. Infection of cardiac fibroblasts with adenoviral constructs containing human recombinant TIMP (AdTIMP-1, -2, -3, and -4) provoked a significant (P < 0.0001) 1.3-fold in increase in bromodeoxyuridine (BrdU) incorporation. Similarly, treatment of cardiac fibroblasts with AdTIMP-1-, -2-, -3-, and -4-conditioned medium led to a 1.2-fold increase in BrdU incorporation (P < 0.0001) that was abolished by pretreatment with anti-TIMP-1, -2, -3, and -4 antibodies. The effects of TIMPs were not mimicked by treating the cells with RS-130830, a broad-based MMP inhibitor, suggesting that the effects of TIMPs were independent of their ability to inhibit MMPs. Infection with AdTIMP-1, -2, -3, and -4 led to a significant increase in alpha-smooth muscle actin staining, consistent with TIMP-induced phenotypic differentiation into myofibroblasts. Finally, infection with AdTIMP-2 resulted in a significant increase in collagen synthesis, whereas infection with AdTIMP-3 resulted in a significant increase in fibroblast apoptosis. TIMPs exert overlapping as well as diverse effects on isolated cardiac fibroblasts. The observation that TIMPs stimulate fibroblast proliferation as well as phenotypic differentiation into myofibroblasts suggests that TIMPs may play an important role in tissue repair in the heart that extends beyond their traditional role as MMP inhibitors.

The Bruton tyrosine kinase inhibitor PCI-32765 thwarts chronic lymphocytic leukemia cell survival and tissue homing in vitro and in vivo

PubMed Central

Ponader, Sabine; Chen, Shih-Shih; Buggy, Joseph J.; Balakrishnan, Kumudha; Gandhi, Varsha; Wierda, William G.; Keating, Michael J.; O'Brien, Susan; Chiorazzi, Nicholas

2012-01-01

B-cell receptor (BCR) signaling is a critical pathway in the pathogenesis of several B-cell malignancies, including chronic lymphocytic leukemia (CLL), and can be targeted by inhibitors of BCR-associated kinases, such as Bruton tyrosine kinase (Btk). PCI-32765, a selective, irreversible Btk inhibitor, is a novel, molecularly targeted agent for patients with B-cell malignancies, and is particularly active in patients with CLL. In this study, we analyzed the mechanism of action of PCI-32765 in CLL, using in vitro and in vivo models, and performed correlative studies on specimens from patients receiving therapy with PCI-32765. PCI-32765 significantly inhibited CLL cell survival, DNA synthesis, and migration in response to tissue homing chemokines (CXCL12, CXCL13). PCI-32765 also down-regulated secretion of BCR-dependent chemokines (CCL3, CCL4) by the CLL cells, both in vitro and in vivo. In an adoptive transfer TCL1 mouse model of CLL, PCI-32765 affected disease progression. In this model, PCI-32765 caused a transient early lymphocytosis, and profoundly inhibited CLL progression, as assessed by weight, development, and extent of hepatospenomegaly, and survival. Our data demonstrate that PCI-32765 effectively inhibits CLL cell migration and survival, possibly explaining some of the characteristic clinical activity of this new targeted agent. PMID:22180443

Pantoprazole, an FDA-approved proton-pump inhibitor, suppresses colorectal cancer growth by targeting T-cell-originated protein kinase

PubMed Central

Sun, Huimin; Xiao, Juanjuan; Lu, Tao; Huang, Guangqian; Chen, Pianpian; Zhang, Jianmin; Zhu, Feng; Li, Hua; Duan, Qiuhong

2016-01-01

T-cell-originated protein kinase (TOPK) is highly expressed in several cancer cells and promotes tumorigenesis and progression, and therefore, it is an important target for drug treatment of tumor. Pantoprazole (PPZ) was identified to be a TOPK inhibitor from FDA-approved drug database by structure based virtual ligand screening. Herein, the data indicated that pantoprazole inhibited TOPK activities by directly binding with TOPK in vitro and in vivo. Ex vivo studies showed that pantoprazole inhibited TOPK activities in JB6 Cl41 cells and HCT 116 colorectal cancer cells. Moreover, knockdown of TOPK in HCT 116 cells decreased their sensitivities to pantoprazole. Results of an in vivo study demonstrated that i.p. injection of pantoprazole in HCT 116 colon tumor-bearing mice effectively suppressed cancer growth. The TOPK downstream signaling molecule phospho-histone H3 in tumor tissues was also decreased after pantoprazole treatment. In short, pantoprazole can suppress growth of colorectal cancer cells as a TOPK inhibitor both in vitro and in vivo. PMID:26967058

Plasmin-dependent proteolysis of tissue factor pathway inhibitor in a mouse model of endotoxemia.

PubMed

Lupu, C; Herlea, O; Tang, H; Lijnen, R H; Lupu, F

2013-01-01

The development of a procoagulant state in sepsis, owing to aberrant expression of tissue factor (TF) and a sharp decrease in the level of its major inhibitor, TF pathway inhibitor (TFPI), could lead to microthrombotic organ failure. The mechanism for the decline in TFPI activity in the lung could involve plasmin-mediated cleavage of the inhibitor. To investigate the effect of plasmin generation on lung-associated TFPI activity, in normal conditions and during infusion of endotoxin (lipopolysaccharide [LPS]) in mice. Plasmin generation and TFPI activity were assayed in the lungs of mice deficient in tissue-type plasminogen (Plg) activator (t-PA) or Plg, at 2 h after LPS or saline injection. The sharp loss of lung-associated TFPI activity at 2 h after LPS challenge paralleled the abrupt increase in plasmin generation. TFPI activity was significantly retained in both t-PA(-/-) and Plg(-/-) mice, which are unable to generate plasmin. The increased plasmin generation during the early stages of sepsis could cleave/inactivate TFPI and thus lead to thrombotic complications. © 2012 International Society on Thrombosis and Haemostasis.

Targeting Human Central Nervous System Protein Kinases: An Isoform Selective p38αMAPK Inhibitor That Attenuates Disease Progression in Alzheimer’s Disease Mouse Models

PubMed Central

2015-01-01

The first kinase inhibitor drug approval in 2001 initiated a remarkable decade of tyrosine kinase inhibitor drugs for oncology indications, but a void exists for serine/threonine protein kinase inhibitor drugs and central nervous system indications. Stress kinases are of special interest in neurological and neuropsychiatric disorders due to their involvement in synaptic dysfunction and complex disease susceptibility. Clinical and preclinical evidence implicates the stress related kinase p38αMAPK as a potential neurotherapeutic target, but isoform selective p38αMAPK inhibitor candidates are lacking and the mixed kinase inhibitor drugs that are promising in peripheral tissue disease indications have limitations for neurologic indications. Therefore, pursuit of the neurotherapeutic hypothesis requires kinase isoform selective inhibitors with appropriate neuropharmacology features. Synaptic dysfunction disorders offer a potential for enhanced pharmacological efficacy due to stress-induced activation of p38αMAPK in both neurons and glia, the interacting cellular components of the synaptic pathophysiological axis, to be modulated. We report a novel isoform selective p38αMAPK inhibitor, MW01-18-150SRM (=MW150), that is efficacious in suppression of hippocampal-dependent associative and spatial memory deficits in two distinct synaptic dysfunction mouse models. A synthetic scheme for biocompatible product and positive outcomes from pharmacological screens are presented. The high-resolution crystallographic structure of the p38αMAPK/MW150 complex documents active site binding, reveals a potential low energy conformation of the bound inhibitor, and suggests a structural explanation for MW150’s exquisite target selectivity. As far as we are aware, MW150 is without precedent as an isoform selective p38MAPK inhibitor or as a kinase inhibitor capable of modulating in vivo stress related behavior. PMID:25676389

Tissue distribution of human acetylcholinesterase and butyrylcholinesterase messenger RNA

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

Jbilo, O.; Barteles, C.F.; Chatonnet, A.

1994-12-31

Tissue distribution of human acetyicholinesterase and butyryicholinesterase messenger RNA. 1 Cholinesterase inhibitors occur naturally in the calabar bean (eserine), green potatoes (solanine), insect-resistant crab apples, the coca plant (cocaine) and snake venom (fasciculin). There are also synthetic cholinesterase inhibitors, for example man-made insecticides. These inhibitors inactivate acetyicholinesterase and butyrylcholinesterase as well as other targets. From a study of the tissue distribution of acetylcholinesterase and butyrylcholinesterase mRNA by Northern blot analysis, we have found the highest levels of butyrylcholinesterase mRNA in the liver and lungs, tissues known as the principal detoxication sites of the human body. These results indicate that butyrylcholinesterasemore » may be a first line of defense against poisons that are eaten or inhaled.« less

Fluorescent imaging of cancerous tissues for targeted surgery

PubMed Central

Bu, Lihong; Shen, Baozhong; Cheng, Zhen

2014-01-01

To maximize tumor excision and minimize collateral damage is the primary goal of cancer surgery. Emerging molecular imaging techniques have to “image-guided surgery” developing into “molecular imaging-guided surgery”, which is termed “targeted surgery” in this review. Consequently, the precision of surgery can be advanced from tissue-scale to molecule-scale, enabling “targeted surgery” to be a component of “targeted therapy”. Evidence from numerous experimental and clinical studies has demonstrated significant benefits of fluorescent imaging in targeted surgery with preoperative molecular diagnostic screening. Fluorescent imaging can help to improve intraoperative staging and enable more radical cytoreduction, detect obscure tumor lesions in special organs, highlight tumor margins, better map lymph node metastases, and identify important normal structures intraoperatively. Though limited tissue penetration of fluorescent imaging and tumor heterogeneity are two major hurdles for current targeted surgery, multimodality imaging and multiplex imaging may provide potential solutions to overcome these issues, respectively. Moreover, though many fluorescent imaging techniques and probes have been investigated, targeted surgery remains at a proof-of-principle stage. The impact of fluorescent imaging on cancer surgery will likely be realized through persistent interdisciplinary amalgamation of research in diverse fields. PMID:25064553

Reduction of Adipose Tissue Mass by the Angiogenesis Inhibitor ALS-L1023 from Melissa officinalis

PubMed Central

Park, Byung Young; Lee, Hyunghee; Woo, Sangee; Yoon, Miso; Kim, Jeongjun; Hong, Yeonhee; Lee, Hee Suk; Park, Eun Kyu; Hahm, Jong Cheon; Kim, Jin Woo; Shin, Soon Shik; Kim, Min-Young; Yoon, Michung

2015-01-01

It has been suggested that angiogenesis modulates adipogenesis and obesity. This study was undertaken to determine whether ALS-L1023 (ALS) prepared by a two-step organic solvent fractionation from Melissa leaves, which exhibits antiangiogenic activity, can regulate adipose tissue growth. The effects of ALS on angiogenesis and extracellular matrix remodeling were measured using in vitro assays. The effects of ALS on adipose tissue growth were investigated in high fat diet-induced obese mice. ALS inhibited VEGF- and bFGF-induced endothelial cell proliferation and suppressed matrix metalloproteinase (MMP) activity in vitro. Compared to obese control mice, administration of ALS to obese mice reduced body weight gain, adipose tissue mass and adipocyte size without affecting appetite. ALS treatment decreased blood vessel density and MMP activity in adipose tissues. ALS reduced the mRNA levels of angiogenic factors (VEGF-A and FGF-2) and MMPs (MMP-2 and MMP-9), whereas ALS increased the mRNA levels of angiogenic inhibitors (TSP-1, TIMP-1, and TIMP-2) in adipose tissues. The protein levels of VEGF, MMP-2 and MMP-9 were also decreased by ALS in adipose tissue. Metabolic changes in plasma lipids, liver triglycerides, and hepatic expression of fatty acid oxidation genes occurred during ALS-induced weight loss. These results suggest that ALS, which has antiangiogenic and MMP inhibitory activities, reduces adipose tissue mass in nutritionally obese mice, demonstrating that adipose tissue growth can be regulated by angiogenesis inhibitors. PMID:26599360

PARP inhibitor rucaparib induces changes in NAD levels in cells and liver tissues as assessed by MRS.

PubMed

Almeida, Gilberto S; Bawn, Carlo M; Galler, Martin; Wilson, Ian; Thomas, Huw D; Kyle, Suzanne; Curtin, Nicola J; Newell, David R; Maxwell, Ross J

2017-09-01

Poly(adenosine diphosphate ribose) polymerases (PARPs) are multifunctional proteins which play a role in many cellular processes. Namely, PARP1 and PARP2 have been shown to be involved in DNA repair, and therefore are valid targets in cancer treatment with PARP inhibitors, such as rucaparib, currently in clinical trials. Proton magnetic resonance spectroscopy ( 1 H-MRS) was used to study the impact of rucaparib in vitro and ex vivo in liver tissue from mice, via quantitative analysis of nicotinamide adenosine diphosphate (NAD + ) spectra, to assess the potential of MRS as a biomarker of the PARP inhibitor response. SW620 (colorectal) and A2780 (ovarian) cancer cell lines, and PARP1 wild-type (WT) and PARP1 knock-out (KO) mice, were treated with rucaparib, temozolomide (methylating agent) or a combination of both drugs. 1 H-MRS spectra were obtained from perchloric acid extracts of tumour cells and mouse liver. Both cell lines showed an increase in NAD + levels following PARP inhibitor treatment in comparison with temozolomide treatment. Liver extracts from PARP1 WT mice showed a significant increase in NAD + levels after rucaparib treatment compared with untreated mouse liver, and a significant decrease in NAD + levels in the temozolomide-treated group. The combination of rucaparib and temozolomide did not prevent the NAD + depletion caused by temozolomide treatment. The 1 H-MRS results show that NAD + levels can be used as a biomarker of PARP inhibitor and methylating agent treatments, and suggest that in vivo measurement of NAD + would be valuable. Copyright © 2017 John Wiley & Sons, Ltd.

Achieving Precision Death with Cell-Cycle Inhibitors that Target DNA Replication and Repair.

PubMed

Lin, Aimee Bence; McNeely, Samuel C; Beckmann, Richard P

2017-07-01

All cancers are characterized by defects in the systems that ensure strict control of the cell cycle in normal tissues. The consequent excess tissue growth can be countered by drugs that halt cell division, and, indeed, the majority of chemotherapeutics developed during the last century work by disrupting processes essential for the cell cycle, particularly DNA synthesis, DNA replication, and chromatid segregation. In certain contexts, the efficacy of these classes of drugs can be impressive, but because they indiscriminately block the cell cycle of all actively dividing cells, their side effects severely constrain the dose and duration with which they can be administered, allowing both normal and malignant cells to escape complete growth arrest. Recent progress in understanding how cancers lose control of the cell cycle, coupled with comprehensive genomic profiling of human tumor biopsies, has shown that many cancers have mutations affecting various regulators and checkpoints that impinge on the core cell-cycle machinery. These defects introduce unique vulnerabilities that can be exploited by a next generation of drugs that promise improved therapeutic windows in patients whose tumors bear particular genomic aberrations, permitting increased dose intensity and efficacy. These developments, coupled with the success of new drugs targeting cell-cycle regulators, have led to a resurgence of interest in cell-cycle inhibitors. This review in particular focuses on the newer strategies that may facilitate better therapeutic targeting of drugs that inhibit the various components that safeguard the fidelity of the fundamental processes of DNA replication and repair. Clin Cancer Res; 23(13); 3232-40. ©2017 AACR . ©2017 American Association for Cancer Research.

Effect of SMURF2 Targeting on Susceptibility to MEK Inhibitors in Melanoma

PubMed Central

2013-01-01

Background The mitogen-activated protein–kinase pathway consisting of the kinases RAF, MEK, and ERK is central to cell proliferation and survival and is deregulated in more than 90% of melanomas. MEK inhibitors are currently trialled in the clinic, but despite efficient target inhibition, cytostatic rather than cytotoxic activity limits their efficacy. Methods We assessed the cytotoxicity to MEK inhibitors (PD184352 and selumetinib) in melanoma cells by toluidine-blue staining, caspase 3 cleavage, and melanoma-sphere growth. Western blotting and quantitative real-time polymerase chain reaction were applied to determine SMAD-specific E3 ubiquitin protein ligase 2 (SMURF2), PAX3, and MITF expression. Human melanoma samples (n = 77) from various stages were analyzed for SMURF2 and PAX3 expression. RNA interference was performed to target SMURF2 during MEK inhibition in vivo in melanoma xenografts in mice and zebrafish. All statistical tests were two-sided. Results Activation of transforming growth factor β (TGF-β) signalling sensitized melanoma cells to the cytotoxic effects of MEK inhibition. Melanoma cells resistant to the cytotoxic effects of MEK inhibitors counteracted TGF-β signalling through overexpression of the E3 ubiquitin ligase SMURF2, which resulted in increased expression of the transcription factors PAX3 and MITF. High MITF expression protected melanoma cells against MEK inhibitor cytotoxicity. Depleting SMURF2 reduced MITF expression and substantially lowered the threshold for MEK inhibitor–induced apoptosis. Moreover, SMURF2 depletion sensitized melanoma cells to the cytotoxic effects of selumetinib, leading to cell death at concentrations approximately 100-fold lower than the concentration required to induce cell death in SMURF2-expressing cells. Mice treated with selumetinib alone at a dosage of 10mg/kg body weight once daily produced no response, but in combination with SMURF2 depletion, selumetinib suppressed tumor growth by 97.9% (95

Inhibitors targeting on cell wall biosynthesis pathway of MRSA.

PubMed

Hao, Haihong; Cheng, Guyue; Dai, Menghong; Wu, Qinghua; Yuan, Zonghui

2012-11-01

Methicillin resistant Staphylococcus aureus (MRSA), widely known as a type of new superbug, has aroused world-wide concern. Cell wall biosynthesis pathway is an old but good target for the development of antibacterial agents. Peptidoglycan and wall teichoic acids (WTAs) biosynthesis are two main processes of the cell wall biosynthesis pathway (CWBP). Other than penicillin-binding proteins (PBPs), some key factors (Mur enzymes, lipid I or II precursor, etc.) in CWBP are becoming attractive molecule targets for the discovery of anti-MRSA compounds. A number of new compounds, with higher affinity for PBPs or with inhibitory activity on such molecule targets in CWBP of MRSA, have been in the pipeline recently. This review concludes recent research achievements and provides a complete picture of CWBP of MRSA, including the peptidoglycan and wall teichoic acids synthesis pathway. The potential inhibitors targeting on CWBP are subsequently presented to improve development of novel therapeutic strategies for MRSA.

Cysteine Protease Inhibitors as Chemotherapy: Lessons from a Parasite Target

NASA Astrophysics Data System (ADS)

Selzer, Paul M.; Pingel, Sabine; Hsieh, Ivy; Ugele, Bernhard; Chan, Victor J.; Engel, Juan C.; Bogyo, Matthew; Russell, David G.; Sakanari, Judy A.; McKerrow, James H.

1999-09-01

Papain family cysteine proteases are key factors in the pathogenesis of cancer invasion, arthritis, osteoporosis, and microbial infections. Targeting this enzyme family is therefore one strategy in the development of new chemotherapy for a number of diseases. Little is known, however, about the efficacy, selectivity, and safety of cysteine protease inhibitors in cell culture or in vivo. We now report that specific cysteine protease inhibitors kill Leishmania parasites in vitro, at concentrations that do not overtly affect mammalian host cells. Inhibition of Leishmania cysteine protease activity was accompanied by defects in the parasite's lysosome/endosome compartment resembling those seen in lysosomal storage diseases. Colocalization of anti-protease antibodies with biotinylated surface proteins and accumulation of undigested debris and protease in the flagellar pocket of treated parasites were consistent with a pathway of protease trafficking from flagellar pocket to the lysosome/endosome compartment. The inhibitors were sufficiently absorbed and stable in vivo to ameliorate the pathology associated with a mouse model of Leishmania infection.

Aptamers as inhibitors of target proteins.

PubMed

Missailidis, S; Hardy, A

2009-08-01

Aptamers as inhibitors of proteins in therapeutic applications offer great advantages over their antibody counterparts and the promise to be developed into the next generation therapeutic agents. However, the control of aptamer intellectual property (IP) by two major players has made aptamers an area difficult to operate and often off-putting for academic and commercial organisations. Yet, their great potential is keeping aptamers at the research forefront, with one aptamer in the clinic and various at different stages of clinical trials. To provide a comprehensive review of the aptamer IP landscape and the issues associated with aptamer therapeutics against protein targets. Extensive review of the scientific and patent literature. Following our experience in developing, patenting and commercialising our aptamers against MUC1 and an extensive review of the literature, we have identified a variety of issues pertaining to the development of aptamers against protein targets for therapeutic applications, their patenting and granting of patents, the original IP holders and their policy, as well as the current market and traits. Despite a slow start, aptamers have been developed against various therapeutic proteins and offer the promise of providing a novel generation of therapeutic entities with a variety of applications.

The Changing Face of Hepatitis C: Recent Advances on HCV Inhibitors Targeting NS5A

PubMed

Rai, Diwakar; Wang, Liu; Jiang, Xuemei; Zhan, Peng; Jia, Haiyong; De Clercq, Erik; Liu, Xinyong

2015-05-05

Current treatment for HCV infections consists of approved direct acting antivirals (DAAs), viz. the protease inhibitors (boceprevir, telaprevir, and simeprevir), NS5B polymerase inhibitors (sofosbuvir) and NS5A inhibitor (ledipasvir) in combination with pegylated interferon α and ribavirin). These treatments have made a great improvement in the treatment of chronic HCV infections in recent years, but their adverse side effects, emergence of resistant mutants, high cost, and increased pill burden have limited their clinical use. Recently, with the increasing knowledge in understanding the HCV life cycle, more targets have been recognized. NS5A protein plays a critical role in assembly of infectious HCV particles and offering potential for HCV therapies. Therefore, discovery and development of novel DAAs targeting NS5A with novel mechanisms of action, is of great necessity to improve the quality of existing HCV treatments. In the present review, we discuss recent advances with NS5A inhibitors with potent anti-HCV activity, and the potential for the development of HCV NS5A inhibitors to combat HCV infections.

Molecular targeted therapies for solid tumors: management of side effects.

PubMed

Grünwald, Viktor; Soltau, Jens; Ivanyi, Philipp; Rentschler, Jochen; Reuter, Christoph; Drevs, Joachim

2009-03-01

This review will provide physicians and oncologists with an overview of side effects related to targeted agents that inhibit vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and mammalian target of rapamycin (mTOR) signaling in the treatment of solid tumors. Such targeted agents can be divided into monoclonal antibodies, tyrosine kinase inhibitors, multitargeted tyrosine kinase inhibitors and serine/threonine kinase inhibitors. Molecular targeted therapies are generally well tolerated, but inhibitory effects on the biological function of the targets in healthy tissue can result in specific treatment-related side effects, particularly with multitargeted agents. We offer some guidance on how to manage adverse events in cancer patients based on the range of options currently available. Copyright 2009 S. Karger AG, Basel.

A Miniaturized Chemical Proteomic Approach for Target Profiling of Clinical Kinase Inhibitors in Tumor Biopsies

PubMed Central

Chamrád, Ivo; Rix, Uwe; Stukalov, Alexey; Gridling, Manuela; Parapatics, Katja; Müller, André C.; Altiok, Soner; Colinge, Jacques; Superti-Furga, Giulio; Haura, Eric B.; Bennett, Keiryn L.

2014-01-01

While targeted therapy based on the idea of attenuating the activity of a preselected, therapeutically relevant protein has become one of the major trends in modern cancer therapy, no truly specific targeted drug has been developed and most clinical agents have displayed a degree of polypharmacology. Therefore, the specificity of anticancer therapeutics has emerged as a highly important but severely underestimated issue. Chemical proteomics is a powerful technique combining postgenomic drug-affinity chromatography with high-end mass spectrometry analysis and bioinformatic data processing to assemble a target profile of a desired therapeutic molecule. Due to high demands on the starting material, however, chemical proteomic studies have been mostly limited to cancer cell lines. Herein, we report a down-scaling of the technique to enable the analysis of very low abundance samples, as those obtained from needle biopsies. By a systematic investigation of several important parameters in pull-downs with the multikinase inhibitor bosutinib, the standard experimental protocol was optimized to 100 µg protein input. At this level, more than 30 well-known targets were detected per single pull-down replicate with high reproducibility. Moreover, as presented by the comprehensive target profile obtained from miniaturized pull-downs with another clinical drug, dasatinib, the optimized protocol seems to be extendable to other drugs of interest. Sixty distinct human and murine targets were finally identified for bosutinib and dasatinib in chemical proteomic experiments utilizing core needle biopsy samples from xenotransplants derived from patient tumor tissue. Altogether, the developed methodology proves robust and generic and holds many promises for the field of personalized health care. PMID:23901793

Bruton tyrosine kinase inhibitors: a promising novel targeted treatment for B cell lymphomas

PubMed Central

Aalipour, Amin; Advani, Ranjana H.

2015-01-01

Summary Constitutive or aberrant signalling of the B cell receptor signalling cascade has been implicated in the propagation and maintenance of a variety of B cell malignancies. Small molecule inhibitors of Bruton tyrosine kinase (BTK), a protein early in this cascade and specifically expressed in B cells, have emerged as a new class of targeted agents. There are several BTK inhibitors, including ONO-WG-307, LFM-A13, dasatinib, CC-292, and PCI-32765 (ibrutinib), in preclinical and/or clinical development of which ibrutinib is currently in phase III trials. Recent clinical data suggest significant activity of ibrutinib as a first in class oral inhibitor of BTK. This review provides an overview of ongoing clinical studies of BTK inhibitors. PMID:24111579

Overcoming acquired BRAF inhibitor resistance in melanoma via targeted inhibition of Hsp90 with ganetespib.

PubMed

Acquaviva, Jaime; Smith, Donald L; Jimenez, John-Paul; Zhang, Chaohua; Sequeira, Manuel; He, Suqin; Sang, Jim; Bates, Richard C; Proia, David A

2014-02-01

Activating BRAF kinase mutations serve as oncogenic drivers in over half of all melanomas, a feature that has been exploited in the development of new molecularly targeted approaches to treat this disease. Selective BRAF(V600E) inhibitors, such as vemurafenib, typically induce initial, profound tumor regressions within this group of patients; however, durable responses have been hampered by the emergence of drug resistance. Here, we examined the activity of ganetespib, a small-molecule inhibitor of Hsp90, in melanoma lines harboring the BRAF(V600E) mutation. Ganetespib exposure resulted in the loss of mutant BRAF expression and depletion of mitogen-activated protein kinase and AKT signaling, resulting in greater in vitro potency and antitumor efficacy compared with targeted BRAF and MAP-ERK kinase (MEK) inhibitors. Dual targeting of Hsp90 and BRAF(V600E) provided combinatorial benefit in vemurafenib-sensitive melanoma cells in vitro and in vivo. Importantly, ganetespib overcame mechanisms of intrinsic and acquired resistance to vemurafenib, the latter of which was characterized by reactivation of extracellular signal-regulated kinase (ERK) signaling. Continued suppression of BRAF(V600E) by vemurafenib potentiated sensitivity to MEK inhibitors after acquired resistance had been established. Ganetespib treatment reduced, but not abolished, elevations in steady-state ERK activity. Profiling studies revealed that the addition of a MEK inhibitor could completely abrogate ERK reactivation in the resistant phenotype, with ganetespib displaying superior combinatorial activity over vemurafenib. Moreover, ganetespib plus the MEK inhibitor TAK-733 induced tumor regressions in vemurafenib-resistant xenografts. Overall these data highlight the potential of ganetespib as a single-agent or combination treatment in BRAF(V600E)-driven melanoma, particularly as a strategy to overcome acquired resistance to selective BRAF inhibitors.

Bisubstrate inhibitors of protein kinases: from principle to practical applications.

PubMed

Lavogina, Darja; Enkvist, Erki; Uri, Asko

2010-01-01

Bisubstrate inhibitors consist of two conjugated fragments, each targeted to a different binding site of a bisubstrate enzyme. The design of bisubstrate inhibitors presupposes the formation of the ternary complex in the course of the catalyzed reaction. The principle advantage of bisubstrate inhibitors is their ability to generate more interactions with the target enzyme that could result in improved affinity and selectivity of the conjugates, when compared with single-site inhibitors. Among phosphotransferases, the approach was first successfully used for adenylate kinase in 1973. Since then, several types of bisubstrate inhibitors have been developed for protein kinases, including conjugates of peptides with nucleotides, adenosine derivatives and potent ATP-competitive inhibitors. Earlier bisubstrate inhibitors had pharmacokinetic qualities that were unsuitable for cellular experiments and hence were mostly used for in vitro studies. The recently constructed conjugates of adenosine derivatives and D-arginine-rich peptides (ARCs) possess high kinase affinity, high biological and chemical stability and good cell plasma membrane penetrative properties that enable their application in the regulation of cellular protein phosphorylation balances in cell and tissue experiments.

Development of Inhibitors Targeting Hypoxia-Inducible Factor 1 and 2 for Cancer Therapy

PubMed Central

Yu, Tianchi

2017-01-01

Hypoxia is frequently observed in solid tumors and also one of the major obstacles for effective cancer therapies. Cancer cells take advantage of their ability to adapt hypoxia to initiate a special transcriptional program that renders them more aggressive biological behaviors. Hypoxia-inducible factors (HIFs) are the key factors that control hypoxia-inducible pathways by regulating the expression of a vast array of genes involved in cancer progression and treatment resistance. HIFs, mainly HIF-1 and -2, have become potential targets for developing novel cancer therapeutics. This article reviews the updated information in tumor HIF pathways, particularly recent advances in the development of HIF inhibitors. These inhibitors interfere with mRNA expression, protein synthesis, protein degradation and dimerization, DNA binding and transcriptional activity of HIF-1 and -2, or both. Despite efforts in the past two decades, no agents directly inhibiting HIFs have been approved for treating cancer patients. By analyzing results of the published reports, we put the perspectives at the end of the article. The therapeutic efficacy of HIF inhibitors may be improved if more efforts are devoted on developing agents that are able to simultaneously target HIF-1 and -2, increasing the penetrating capacity of HIF inhibitors, and selecting suitable patient subpopulations for clinical trials. PMID:28332352

Notch Inhibitors for Cancer Treatment

PubMed Central

Espinoza, Ingrid; Miele, Lucio

2013-01-01

Notch signaling is an evolutionarily conserved cell signaling pathway involved in cell fate during development, stem cell renewal and differentiation in postnatal tissues. Roles for Notch in carcinogenesis, in the biology of cancer stem cells and tumor angiogenesis have been reported. These features identify Notch as a potential therapeutic target in oncology. Based on the molecular structure of Notch receptor, Notch ligands and Notch activators, a set of Notch pathway inhibitors have been developed. Most of these inhibitors had shown anti-tumor effects in preclinical studies. At the same time, the combinatorial effect of these inhibitors with current chemotherapeutical drugs still under study in different clinical trials. In this review, we describe the basics of Notch signaling and the role of Notch in normal and cancer stem cells as a logic way to develop different Notch inhibitors and their current stage of progress for cancer patient’s treatment. PMID:23458608

Identification of alsterpaullone as a novel small molecule inhibitor to target group 3 medulloblastoma.

PubMed

Faria, Claudia C; Agnihotri, Sameer; Mack, Stephen C; Golbourn, Brian J; Diaz, Roberto J; Olsen, Samantha; Bryant, Melissa; Bebenek, Matthew; Wang, Xin; Bertrand, Kelsey C; Kushida, Michelle; Head, Renee; Clark, Ian; Dirks, Peter; Smith, Christian A; Taylor, Michael D; Rutka, James T

2015-08-28

Advances in the molecular biology of medulloblastoma revealed four genetically and clinically distinct subgroups. Group 3 medulloblastomas are characterized by frequent amplifications of the oncogene MYC, a high incidence of metastasis, and poor prognosis despite aggressive therapy. We investigated several potential small molecule inhibitors to target Group 3 medulloblastomas based on gene expression data using an in silico drug screen. The Connectivity Map (C-MAP) analysis identified piperlongumine as the top candidate drug for non-WNT medulloblastomas and the cyclin-dependent kinase (CDK) inhibitor alsterpaullone as the compound predicted to have specific antitumor activity against Group 3 medulloblastomas. To validate our findings we used these inhibitors against established Group 3 medulloblastoma cell lines. The C-MAP predicted drugs reduced cell proliferation in vitro and increased survival in Group 3 medulloblastoma xenografts. Alsterpaullone had the highest efficacy in Group 3 medulloblastoma cells. Genomic profiling of Group 3 medulloblastoma cells treated with alsterpaullone confirmed inhibition of cell cycle-related genes, and down-regulation of MYC. Our results demonstrate the preclinical efficacy of using a targeted therapy approach for Group 3 medulloblastomas. Specifically, we provide rationale for advancing alsterpaullone as a targeted therapy in Group 3 medulloblastoma.

Targeted Delivery of Proteasome Inhibitors to Somatostatin-Receptor-Expressing Cancer Cells by Octreotide Conjugation.

PubMed

Beck, Philipp; Cui, Haissi; Hegemann, Julian D; Marahiel, Mohammed A; Krüger, Achim; Groll, Michael

2015-12-01

Clinical application of proteasome inhibitors (PIs) is so far limited to peripheral blood cancers due to the pronounced cytotoxicity towards all cell types. Targeted delivery of PIs could permit the treatment of other cancers along with decreasing side effects. Herein we describe the first small-molecule proteasome inhibitor conjugate for targeted delivery, created by fusing PIs to a synthetic ligand of somatostatin receptors, which are highly expressed in a variety of tumors. X-ray crystallographic studies and in vitro IC50 measurements demonstrated that addition of the cyclopeptide octreotide as a targeting vehicle does not affect the PI's binding mode. The cytotoxicity of the conjugate against somatostatin-receptor-expressing cells was up to 11-fold higher than that of a non-targeting surrogate. We have therefore established PIs as a new payload for drug conjugates and have shown that targeted delivery thereof could be a promising approach for the broader application of this FDA-approved class of compounds. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tissue Inhibitor of Metalloproteinase-3 (TIMP3) Promotes Endothelial Apoptosis via a Caspase-Independent Mechanism

PubMed Central

Qi, Jian Hua; Anand-Apte, Bela

2015-01-01

Tissue Inhibitor of Metalloproteinases-3 (TIMP3) is a tumor suppressor and a potent inhibitor of angiogenesis. TIMP3 exerts its anti-angiogenic effect via a direct interaction with vascular endothelial growth factor (VEGF) receptor-2 (KDR) and inhibition of proliferation, migration and tube formation of endothelial cells (ECs). TIMP3 has also been shown to induce apoptosis in some cancer cells and vascular smooth muscle cells via MMP inhibition and caspase-dependent mechanisms. In this study, we examined the molecular mechanisms of TIMP3-mediated apoptosis in endothelial cells. We have previously demonstrated that mice developed smaller tumors with decreased vascularity when injected with breast carcinoma cells overexpressing TIMP3, than with control breast carcinoma cells. TIMP3 overexpression resulted in increased apoptosis in human breast carcinoma (MDA-MB435) in vivo but not in vitro. However, TIMP3 could induce apoptosis in endothelial cells (ECs) in vitro. The apoptotic activity of TIMP3 in ECs appears to be independent of MMP inhibitory activity. Furthermore, the equivalent expression of functional TIMP3 promoted apoptosis and caspase activation in endothelial cells expressing KDR (PAE/KDR), but not in endothelial cells expressing PDGF beta-receptor (PAE/β-R). Surprisingly, the apoptotic activity of TIMP3 appears to be independent of caspases. TIMP3 inhibited matrix-induced focal adhesion kinase (FAK) tyrosine phosphorylation and association with paxillin and disrupted the incorporation of β3 integrin, FAK and paxillin into focal adhesion contacts on the matrix, which were not affected by caspase inhibitors. Thus, TIMP3 may induce apoptosis in ECs by triggering a caspase-independent cell death pathway and targeting a FAK-dependent survival pathway. PMID:25558000

Tissue inhibitor of metalloproteinase-3 (TIMP3) promotes endothelial apoptosis via a caspase-independent mechanism.

PubMed

Qi, Jian Hua; Anand-Apte, Bela

2015-04-01

Tissue inhibitor of metalloproteinases-3 (TIMP3) is a tumor suppressor and a potent inhibitor of angiogenesis. TIMP3 exerts its anti-angiogenic effect via a direct interaction with vascular endothelial growth factor (VEGF) receptor-2 (KDR) and inhibition of proliferation, migration and tube formation of endothelial cells (ECs). TIMP3 has also been shown to induce apoptosis in some cancer cells and vascular smooth muscle cells via MMP inhibition and caspase-dependent mechanisms. In this study, we examined the molecular mechanisms of TIMP3-mediated apoptosis in endothelial cells. We have previously demonstrated that mice developed smaller tumors with decreased vascularity when injected with breast carcinoma cells overexpressing TIMP3, than with control breast carcinoma cells. TIMP3 overexpression resulted in increased apoptosis in human breast carcinoma (MDA-MB435) in vivo but not in vitro. However, TIMP3 could induce apoptosis in ECs in vitro. The apoptotic activity of TIMP3 in ECs appears to be independent of MMP inhibitory activity. Furthermore, the equivalent expression of functional TIMP3 promoted apoptosis and caspase activation in ECs expressing KDR (PAE/KDR), but not in ECs expressing PDGF beta-receptor (PAE/β-R). Surprisingly, the apoptotic activity of TIMP3 appears to be independent of caspases. TIMP3 inhibited matrix-induced focal adhesion kinase (FAK) tyrosine phosphorylation and association with paxillin and disrupted the incorporation of β3 integrin, FAK and paxillin into focal adhesion contacts on the matrix, which were not affected by caspase inhibitors. Thus, TIMP3 may induce apoptosis in ECs by triggering a caspase-independent cell death pathway and targeting a FAK-dependent survival pathway.

Tricyclic GyrB/ParE (TriBE) Inhibitors. A new class of broad-spectrum dual-targeting antibacterial agents

DOE PAGES

Tari, Leslie W.; Li, Xiaoming; Trzoss, Michael; ...

2013-12-26

Increasing resistance to every major class of antibiotics and a dearth of novel classes of antibacterial agents in development pipelines has created a dwindling reservoir of treatment options for serious bacterial infections. The bacterial type IIA topoisomerases, DNA gyrase and topoisomerase IV, are validated antibacterial drug targets with multiple prospective drug binding sites, including the catalytic site targeted by the fluoroquinolone antibiotics. Growing resistance to fluoroquinolones, frequently mediated by mutations in the drug-binding site, is increasingly limiting the utility of this antibiotic class, prompting the search for other inhibitor classes that target different sites on the topoisomerase complexes. The highlymore » conserved ATP-binding subunits of DNA gyrase (GyrB) and topoisomerase IV (ParE) have long been recognized as excellent candidates for the development of dual-targeting antibacterial agents with broad-spectrum potential. However, to date, no natural product or small molecule inhibitors targeting these sites have succeeded in the clinic, and no inhibitors of these enzymes have yet been reported with broad-spectrum antibacterial activity encompassing the majority of Gram-negative pathogens. Using structure-based drug design (SBDD), we have created a novel dual-targeting pyrimidoindole inhibitor series with exquisite potency against GyrB and ParE enzymes from a broad range of clinically important pathogens. Inhibitors from this series demonstrate potent, broad-spectrum antibacterial activity against Gram-positive and Gram-negative pathogens of clinical importance, including fluoroquinolone resistant and multidrug resistant strains. Moreover, lead compounds have been discovered with clinical potential; they are well tolerated in animals, and efficacious in Gram-negative infection models.« less

Tricyclic GyrB/ParE (TriBE) Inhibitors. A new class of broad-spectrum dual-targeting antibacterial agents

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

Tari, Leslie W.; Li, Xiaoming; Trzoss, Michael

Increasing resistance to every major class of antibiotics and a dearth of novel classes of antibacterial agents in development pipelines has created a dwindling reservoir of treatment options for serious bacterial infections. The bacterial type IIA topoisomerases, DNA gyrase and topoisomerase IV, are validated antibacterial drug targets with multiple prospective drug binding sites, including the catalytic site targeted by the fluoroquinolone antibiotics. Growing resistance to fluoroquinolones, frequently mediated by mutations in the drug-binding site, is increasingly limiting the utility of this antibiotic class, prompting the search for other inhibitor classes that target different sites on the topoisomerase complexes. The highlymore » conserved ATP-binding subunits of DNA gyrase (GyrB) and topoisomerase IV (ParE) have long been recognized as excellent candidates for the development of dual-targeting antibacterial agents with broad-spectrum potential. However, to date, no natural product or small molecule inhibitors targeting these sites have succeeded in the clinic, and no inhibitors of these enzymes have yet been reported with broad-spectrum antibacterial activity encompassing the majority of Gram-negative pathogens. Using structure-based drug design (SBDD), we have created a novel dual-targeting pyrimidoindole inhibitor series with exquisite potency against GyrB and ParE enzymes from a broad range of clinically important pathogens. Inhibitors from this series demonstrate potent, broad-spectrum antibacterial activity against Gram-positive and Gram-negative pathogens of clinical importance, including fluoroquinolone resistant and multidrug resistant strains. Moreover, lead compounds have been discovered with clinical potential; they are well tolerated in animals, and efficacious in Gram-negative infection models.« less

Tricyclic GyrB/ParE (TriBE) Inhibitors: A New Class of Broad-Spectrum Dual-Targeting Antibacterial Agents

PubMed Central

Tari, Leslie W.; Li, Xiaoming; Trzoss, Michael; Bensen, Daniel C.; Chen, Zhiyong; Lam, Thanh; Zhang, Junhu; Lee, Suk Joong; Hough, Grayson; Phillipson, Doug; Akers-Rodriguez, Suzanne; Cunningham, Mark L.; Kwan, Bryan P.; Nelson, Kirk J.; Castellano, Amanda; Locke, Jeff B.; Brown-Driver, Vickie; Murphy, Timothy M.; Ong, Voon S.; Pillar, Chris M.; Shinabarger, Dean L.; Nix, Jay; Lightstone, Felice C.; Wong, Sergio E.; Nguyen, Toan B.; Shaw, Karen J.; Finn, John

2013-01-01

Increasing resistance to every major class of antibiotics and a dearth of novel classes of antibacterial agents in development pipelines has created a dwindling reservoir of treatment options for serious bacterial infections. The bacterial type IIA topoisomerases, DNA gyrase and topoisomerase IV, are validated antibacterial drug targets with multiple prospective drug binding sites, including the catalytic site targeted by the fluoroquinolone antibiotics. However, growing resistance to fluoroquinolones, frequently mediated by mutations in the drug-binding site, is increasingly limiting the utility of this antibiotic class, prompting the search for other inhibitor classes that target different sites on the topoisomerase complexes. The highly conserved ATP-binding subunits of DNA gyrase (GyrB) and topoisomerase IV (ParE) have long been recognized as excellent candidates for the development of dual-targeting antibacterial agents with broad-spectrum potential. However, to date, no natural product or small molecule inhibitors targeting these sites have succeeded in the clinic, and no inhibitors of these enzymes have yet been reported with broad-spectrum antibacterial activity encompassing the majority of Gram-negative pathogens. Using structure-based drug design (SBDD), we have created a novel dual-targeting pyrimidoindole inhibitor series with exquisite potency against GyrB and ParE enzymes from a broad range of clinically important pathogens. Inhibitors from this series demonstrate potent, broad-spectrum antibacterial activity against Gram-positive and Gram-negative pathogens of clinical importance, including fluoroquinolone resistant and multidrug resistant strains. Lead compounds have been discovered with clinical potential; they are well tolerated in animals, and efficacious in Gram-negative infection models. PMID:24386374

Metabolic factors, adipose tissue, and plasminogen activator inhibitor-1 levels in Type 2 diabetes

USDA-ARS?s Scientific Manuscript database

Plasminogen activator inhibitor-1 (PAI-1) production by adipose tissue is increased in obesity, and its circulating levels are high in type 2 diabetes. PAI-1 increases cardiovascular risk by favoring clot stability, interfering with vascular remodeling, or both. We investigated in obese diabetic per...

Sex- and Tissue-specific Functions of Drosophila Doublesex Transcription Factor Target Genes

PubMed Central

Clough, Emily; Jimenez, Erin; Kim, Yoo-Ah; Whitworth, Cale; Neville, Megan C.; Hempel, Leonie; Pavlou, Hania J.; Chen, Zhen-Xia; Sturgill, David; Dale, Ryan; Smith, Harold E.; Przytycka, Teresa M.; Goodwin, Stephen F.; Van Doren, Mark; Oliver, Brian

2014-01-01

Primary sex determination “switches” evolve rapidly, but Doublesex (DSX) related transcription factors (DMRTs) act downstream of these switches to control sexual development in most animal species. Drosophila dsx encodes female- and male-specific isoforms (DSXF and DSXM), but little is known about how dsx controls sexual development, whether DSXF and DSXM bind different targets, or how DSX proteins direct different outcomes in diverse tissues. We undertook genome-wide analyses to identify DSX targets using in vivo occupancy, binding site prediction, and evolutionary conservation. We find that DSXF and DSXM bind thousands of the same targets in multiple tissues in both sexes, yet these targets have sex- and tissue-specific functions. Interestingly, DSX targets show considerable overlap with targets identified for mouse DMRT1. DSX targets include transcription factors and signaling pathway components providing for direct and indirect regulation of sex-biased expression. PMID:25535918

Method to Reduce Target Motion Through Needle-Tissue Interactions.

PubMed

Oldfield, Matthew J; Leibinger, Alexander; Seah, Tian En Timothy; Rodriguez Y Baena, Ferdinando

2015-11-01

During minimally invasive surgical procedures, it is often important to deliver needles to particular tissue volumes. Needles, when interacting with a substrate, cause deformation and target motion. To reduce reliance on compensatory intra-operative imaging, a needle design and novel delivery mechanism is proposed. Three-dimensional finite element simulations of a multi-segment needle inserted into a pre-existing crack are presented. The motion profiles of the needle segments are varied to identify methods that reduce target motion. Experiments are then performed by inserting a needle into a gelatine tissue phantom and measuring the internal target motion using digital image correlation. Simulations indicate that target motion is reduced when needle segments are stroked cyclically and utilise a small amount of retraction instead of being held stationary. Results are confirmed experimentally by statistically significant target motion reductions of more than 8% during cyclic strokes and 29% when also incorporating retraction, with the same net insertion speed. By using a multi-segment needle and taking advantage of frictional interactions on the needle surface, it is demonstrated that target motion ahead of an advancing needle can be substantially reduced.

The kidney as a new target for antidiabetic drugs: SGLT2 inhibitors.

PubMed

Cangoz, S; Chang, Y-Y; Chempakaseril, S J; Guduru, R C; Huynh, L M; John, J S; John, S T; Joseph, M E; Judge, R; Kimmey, R; Kudratov, K; Lee, P J; Madhani, I C; Shim, P J; Singh, S; Singh, S; Ruchalski, C; Raffa, R B

2013-10-01

A novel class of antidiabetic drugs - SGLT2 (Na(+) /glucose cotransporter type 2) inhibitors - target renal reabsorption of glucose and promote normal glucose levels, independent of insulin production or its action at receptors. We review this new mechanistic approach and the reported efficacy and safety of clinical testing of lead compounds. Information was obtained from various bibliographic sources, including PubMed and others, on the basic science and the clinical trials of SGLT2 inhibitors. The information was then summarized and evaluated from the perspective of contribution to a fuller understanding of the potential and current status of the lead clinical candidates. Diabetes mellitus is a spectrum of disorders that involves inadequate insulin function resulting in adverse health sequelae due to acute and chronic hyperglycaemia. Current antidiabetic pharmacotherapy primarily addresses either insulin production at the pancreatic β-cells or insulin action at insulin receptors. These drugs have less than full clinical effectiveness and sometimes therapy-limiting adverse effects. The third major component of glucose balance, namely elimination, has not been a significant therapeutic target to date. SGLT2 inhibitors are a novel approach. A sufficient number of clinical trials have been conducted on sufficiently chemically diverse SGLT2 inhibitors to reasonably conclude that they have efficacy (HbA1c reductions of 0·4-1%), and thus far, the majority of adverse effects have been mild and transitory or treatable, with the caveat of possible association with increased risk of breast cancer in women and bladder cancer in men. © 2013 John Wiley & Sons Ltd.

Hierarchical Targeting Strategy for Enhanced Tumor Tissue Accumulation/Retention and Cellular Internalization.

PubMed

Wang, Sheng; Huang, Peng; Chen, Xiaoyuan

2016-09-01

Targeted delivery of therapeutic agents is an important way to improve the therapeutic index and reduce side effects. To design nanoparticles for targeted delivery, both enhanced tumor tissue accumulation/retention and enhanced cellular internalization should be considered simultaneously. So far, there have been very few nanoparticles with immutable structures that can achieve this goal efficiently. Hierarchical targeting, a novel targeting strategy based on stimuli responsiveness, shows good potential to enhance both tumor tissue accumulation/retention and cellular internalization. Here, the recent design and development of hierarchical targeting nanoplatforms, based on changeable particle sizes, switchable surface charges and activatable surface ligands, will be introduced. In general, the targeting moieties in these nanoplatforms are not activated during blood circulation for efficient tumor tissue accumulation, but re-activated by certain internal or external stimuli in the tumor microenvironment for enhanced cellular internalization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Design of New HIV-IN Tethered Bifunctional Inhibitors using Multiple Microdomain Targeted Docking.

PubMed

Ciubotaru, Mihai; Musat, Mihaela Georgiana; Surleac, Marius; Ionita, Elena; Petrescu, Andrei Jose; Abele, Edgars; Abele, Ramona

2018-04-05

Currently used antiretroviral HIV therapy drugs exclusively target critical groups in the enzymes essential for the viral life cycle. Increased mutagenesis of their genes, changes these viral enzymes which once mutated can evade therapeutic targeting, effects which confer drug resistance. To circumvent this, our review addresses a strategy to design and derive HIV-Integrase (HIV-IN) inhibitors which simultaneously target two IN functional domains, rendering it inactive even if the enzyme accumulates many mutations. First we review the enzymatic role of IN to insert the copied viral DNA into a chromosome of the host T lymphocyte, highlighting its main functional and structural features to be subjected to inhibitory action. From a functional and structural perspective we present all classes of HIV-IN inhibitors with their most representative candidates. For each chosen compound we also explain its mechanism of IN inhibition. We use the recently resolved cryo EM IN tetramer intasome DNA complex [1] onto which we dock various reference IN inhibitory chemical scaffolds such as to target adjacent functional IN domains. Pairing compounds with complementary activity, which dock in the vicinity of a IN structural microdomain, we design bifunctional new drugs which may not only be more resilient to IN mutations but also may be more potent inhibitors than their original counterparts. In the end of our review we propose synthesis pathways to link such paired compounds with enhanced synergistic IN inhibitory effects. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Receptor tyrosine kinase (c-Kit) inhibitors: a potential therapeutic target in cancer cells

PubMed Central

Abbaspour Babaei, Maryam; Kamalidehghan, Behnam; Saleem, Mohammad; Huri, Hasniza Zaman; Ahmadipour, Fatemeh

2016-01-01

c-Kit, a receptor tyrosine kinase, is involved in intracellular signaling, and the mutated form of c-Kit plays a crucial role in occurrence of some cancers. The function of c-Kit has led to the concept that inhibiting c-Kit kinase activity can be a target for cancer therapy. The promising results of inhibition of c-Kit for treatment of cancers have been observed in some cancers such as gastrointestinal stromal tumor, acute myeloid leukemia, melanoma, and other tumors, and these results have encouraged attempts toward improvement of using c-Kit as a capable target for cancer therapy. This paper presents the findings of previous studies regarding c-Kit as a receptor tyrosine kinase and an oncogene, as well as its gene targets and signaling pathways in normal and cancer cells. The c-Kit gene location, protein structure, and the role of c-Kit in normal cell have been discussed. Comprehending the molecular mechanism underlying c-Kit-mediated tumorogenesis is consequently essential and may lead to the identification of future novel drug targets. The potential mechanisms by which c-Kit induces cellular transformation have been described. This study aims to elucidate the function of c-Kit for future cancer therapy. In addition, it has c-Kit inhibitor drug properties and their functions have been listed in tables and demonstrated in schematic pictures. This review also has collected previous studies that targeted c-Kit as a novel strategy for cancer therapy. This paper further emphasizes the advantages of this approach, as well as the limitations that must be addressed in the future. Finally, although c-Kit is an attractive target for cancer therapy, based on the outcomes of treatment of patients with c-Kit inhibitors, it is unlikely that Kit inhibitors alone can lead to cure. It seems that c-Kit mutations alone are not sufficient for tumorogenesis, but do play a crucial role in cancer occurrence. PMID:27536065

Antitumor efficacy profile of PKI-402, a dual phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor.

PubMed

Mallon, Robert; Hollander, Irwin; Feldberg, Larry; Lucas, Judy; Soloveva, Veronica; Venkatesan, Aranapakam; Dehnhardt, Christoph; Delos Santos, Efren; Chen, Zecheng; Dos Santos, Osvaldo; Ayral-Kaloustian, Semiramis; Gibbons, Jay

2010-04-01

PKI-402 is a selective, reversible, ATP-competitive, equipotent inhibitor of class I phosphatidylinositol 3-kinases (PI3K), including PI3K-alpha mutants, and mammalian target of rapamycin (mTOR; IC(50) versus PI3K-alpha = 2 nmol/L). PKI-402 inhibited growth of human tumor cell lines derived from breast, brain (glioma), pancreas, and non-small cell lung cancer tissue and suppressed phosphorylation of PI3K and mTOR effector proteins (e.g., Akt at T308) at concentrations that matched those that inhibited cell growth. In MDA-MB-361 [breast: Her2(+) and PIK3CA mutant (E545K)], 30 nmol/L PKI-402 induced cleaved poly(ADP-ribose) polymerase (PARP), a marker for apoptosis. In vivo, PKI-402 inhibited tumor growth in MDA-MB-361, glioma (U87MG), and lung (A549) xenograft models. In MDA-MB-361, PKI-402 at 100 mg/kg (daily for 5 days, one round) reduced initial tumor volume of 260 mm(3) to 129 mm(3) and prevented tumor regrowth for 70 days. In MDA-MB-361 tumors, PKI-402 (100 mg/kg, single dose) suppressed Akt phosphorylation (at T308) and induced cleaved PARP. Suppression of phosphorylated Akt (p-Akt) was complete at 8 hours and still evident at 24 hours. Cleaved PARP was evident at 8 and 24 hours. In normal tissue (heart and lung), PKI-402 (100 mg/kg) had minimal effect on p-Akt, with no detectable cleaved PARP. Preferential accumulation of PKI-402 in tumor tissue was observed. Complete, sustained suppression of Akt phosphorylation may cause tumor regression in MDA-MB-361 and other xenograft models. We are testing whether dual PI3K/mTOR inhibitors can durably suppress p-Akt, induce cleaved PARP, and cause tumor regression in a diverse set of human tumor xenograft models. Mol Cancer Ther; 9(4); 976-84. (c)2010 AACR.

Tissue phosphoproteomics with PolyMAC identifies potential therapeutic targets in a transgenic mouse model of HER2 positive breast cancer

PubMed Central

Searleman, Adam C.; Iliuk, Anton B.; Collier, Timothy S.; Chodosh, Lewis A.; Tao, W. Andy; Bose, Ron

2014-01-01

Altered protein phosphorylation is a feature of many human cancers that can be targeted therapeutically. Phosphopeptide enrichment is a critical step for maximizing the depth of phosphoproteome coverage by MS, but remains challenging for tissue specimens because of their high complexity. We describe the first analysis of a tissue phosphoproteome using polymer-based metal ion affinity capture (PolyMAC), a nanopolymer that has excellent yield and specificity for phosphopeptide enrichment, on a transgenic mouse model of HER2-driven breast cancer. By combining phosphotyrosine immunoprecipitation with PolyMAC, 411 unique peptides with 139 phosphotyrosine, 45 phosphoserine, and 29 phosphothreonine sites were identified from five LC-MS/MS runs. Combining reverse phase liquid chromatography fractionation at pH 8.0 with PolyMAC identified 1571 unique peptides with 1279 phosphoserine, 213 phosphothreonine, and 21 phosphotyrosine sites from eight LC-MS/MS runs. Linear motif analysis indicated that many of the phosphosites correspond to well-known phosphorylation motifs. Analysis of the tyrosine phosphoproteome with the Drug Gene Interaction database uncovered a network of potential therapeutic targets centered on Src family kinases with inhibitors that are either FDA-approved or in clinical development. These results demonstrate that PolyMAC is well suited for phosphoproteomic analysis of tissue specimens. PMID:24723360

Inhibitors of Fatty Acid Amide Hydrolase and Monoacylglycerol Lipase: New Targets for Future Antidepressants.

PubMed

Ogawa, Shintaro; Kunugi, Hiroshi

2015-01-01

Cannabis and analogs of Δ⁹-tetrahydrocannabinol have been used for therapeutic purposes, but their therapeutic use remains limited because of various adverse effects. Endogenous cannabinoids have been discovered, and dysregulation of endocannabinoid signaling is implicated in the pathophysiology of major depressive disorder (MDD). Recently, endocannabinoid hydrolytic enzymes such as fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) have become new therapeutic targets in the treatment of MDD. Several FAAH or MAGL inhibitors are reported to have no cannabimimetic side effects and, therefore, are new potential therapeutic options for patients with MDD who are resistant to first-line antidepressants (selective serotonin and serotonin-norepinephrine reuptake inhibitors). In this review, we focus on the possible relationships between MDD and the endocannabinoid system as well as the inhibitors' therapeutic potential. MAGL inhibitors may reduce inflammatory responses through activation of cannabinoid receptor type 2. In the hypothalamic-pituitary-adrenal axis, repeated FAAH inhibitor administration may be beneficial for reducing circulating glucocorticoid levels. Both FAAH and MAGL inhibitors may contribute to dopaminergic system regulation. Recently, several new inhibitors have been developed with strong potency and selectivity. FAAH inhibitor, MAGL inhibitor, or dual blocker use would be promising new treatments for MDD. Further pre-clinical studies and clinical trials using these inhibitors are warranted.

Hsp90 Inhibitors as New Leads To Target Parasitic Diarrheal Diseases

PubMed Central

Shahinas, Dea; Bryant, Clifford; Hirata, Ken; Miyamoto, Yukiko; Hwang, Grace; Gut, Jiri; Renslo, Adam R.; Pillai, Dylan R.; Eckmann, Lars; Reed, Sharon L.; McKerrow, James H.

2014-01-01

Entamoeba histolytica and Giardia lamblia are anaerobic protozoan parasites that cause amebiasis and giardiasis, two of the most common diarrheal diseases worldwide. Current therapy relies on metronidazole, but resistance has been reported and the drug has significant adverse effects. Therefore, it is critical to search for effective, better-tolerated antiamebic and antigiardial drugs. We synthesized several examples of a recently reported class of Hsp90 inhibitors and evaluated these compounds as potential leads for antiparasitic chemotherapy. Several of these inhibitors showed strong in vitro activity against both E. histolytica and G. lamblia trophozoites. The inhibitors were rescreened to discriminate between amebicidal and giardicidal activity and general cytotoxicity toward a mammalian cell line. No mammalian cytotoxicity was found at >100 μM for 48 h for any of the inhibitors. To understand the mechanism of action, a competitive binding assay was performed using the fluorescent ATP analogue bis-ANS (4,4′-dianilino-1,1′-binaphthyl-5,5′-disulfonic acid dipotassium salt) and recombinant E. histolytica Hsp90 preincubated in both the presence and absence of Hsp90 inhibitors. There was significant reduction in fluorescence compared to the level in the control, suggesting that E. histolytica Hsp90 is a selective target. The in vivo efficacy and safety of one Hsp90 inhibitor in a mouse model of amebic colitis and giardiasis was demonstrated by significant inhibition of parasite growth at a single oral dose of 5 mg/kg of body weight/day for 7 days and 10 mg/kg/day for 3 days. Considering the results for in vitro activity and in vivo efficacy, Hsp90 inhibitors represent a promising therapeutic option for amebiasis and giardiasis. PMID:24820073

Masitinib (AB1010), a Potent and Selective Tyrosine Kinase Inhibitor Targeting KIT

PubMed Central

Dubreuil, Patrice; Letard, Sébastien; Ciufolini, Marco; Gros, Laurent; Humbert, Martine; Castéran, Nathalie; Borge, Laurence; Hajem, Bérengère; Lermet, Anne; Sippl, Wolfgang; Voisset, Edwige; Arock, Michel; Auclair, Christian; Leventhal, Phillip S.; Mansfield, Colin D.; Moussy, Alain; Hermine, Olivier

2009-01-01

Background The stem cell factor receptor, KIT, is a target for the treatment of cancer, mastocytosis, and inflammatory diseases. Here, we characterise the in vitro and in vivo profiles of masitinib (AB1010), a novel phenylaminothiazole-type tyrosine kinase inhibitor that targets KIT. Methodology/Principal Findings In vitro, masitinib had greater activity and selectivity against KIT than imatinib, inhibiting recombinant human wild-type KIT with an half inhibitory concentration (IC50) of 200±40 nM and blocking stem cell factor-induced proliferation and KIT tyrosine phosphorylation with an IC50 of 150±80 nM in Ba/F3 cells expressing human or mouse wild-type KIT. Masitinib also potently inhibited recombinant PDGFR and the intracellular kinase Lyn, and to a lesser extent, fibroblast growth factor receptor 3. In contrast, masitinib demonstrated weak inhibition of ABL and c-Fms and was inactive against a variety of other tyrosine and serine/threonine kinases. This highly selective nature of masitinib suggests that it will exhibit a better safety profile than other tyrosine kinase inhibitors; indeed, masitinib-induced cardiotoxicity or genotoxicity has not been observed in animal studies. Molecular modelling and kinetic analysis suggest a different mode of binding than imatinib, and masitinib more strongly inhibited degranulation, cytokine production, and bone marrow mast cell migration than imatinib. Furthermore, masitinib potently inhibited human and murine KIT with activating mutations in the juxtamembrane domain. In vivo, masitinib blocked tumour growth in mice with subcutaneous grafts of Ba/F3 cells expressing a juxtamembrane KIT mutant. Conclusions Masitinib is a potent and selective tyrosine kinase inhibitor targeting KIT that is active, orally bioavailable in vivo, and has low toxicity. PMID:19789626

Engineering Factor Xa Inhibitor with Multiple Platelet-Binding Sites Facilitates its Platelet Targeting

NASA Astrophysics Data System (ADS)

Zhu, Yuanjun; Li, Ruyi; Lin, Yuan; Shui, Mengyang; Liu, Xiaoyan; Chen, Huan; Wang, Yinye

2016-07-01

Targeted delivery of antithrombotic drugs centralizes the effects in the thrombosis site and reduces the hemorrhage side effects in uninjured vessels. We have recently reported that the platelet-targeting factor Xa (FXa) inhibitors, constructed by engineering one Arg-Gly-Asp (RGD) motif into Ancylostoma caninum anticoagulant peptide 5 (AcAP5), can reduce the risk of systemic bleeding than non-targeted AcAP5 in mouse arterial injury model. Increasing the number of platelet-binding sites of FXa inhibitors may facilitate their adhesion to activated platelets, and further lower the bleeding risks. For this purpose, we introduced three RGD motifs into AcAP5 to generate a variant NR4 containing three platelet-binding sites. NR4 reserved its inherent anti-FXa activity. Protein-protein docking showed that all three RGD motifs were capable of binding to platelet receptor αIIbβ3. Molecular dynamics simulation demonstrated that NR4 has more opportunities to interact with αIIbβ3 than single-RGD-containing NR3. Flow cytometry analysis and rat arterial thrombosis model further confirmed that NR4 possesses enhanced platelet targeting activity. Moreover, NR4-treated mice showed a trend toward less tail bleeding time than NR3-treated mice in carotid artery endothelium injury model. Therefore, our data suggest that engineering multiple binding sites in one recombinant protein is a useful tool to improve its platelet-targeting efficiency.

An Accessory Protease Inhibitor to Increase the Yield and Quality of a Tumour-Targeting mAb in Nicotiana benthamiana Leaves

PubMed Central

Jutras, Philippe V.; Marusic, Carla; Lonoce, Chiara; Deflers, Carole; Goulet, Marie-Claire; Benvenuto, Eugenio; Donini, Marcello

2016-01-01

The overall quality of recombinant IgG antibodies in plants is dramatically compromised by host endogenous proteases. Different approaches have been developed to reduce the impact of endogenous proteolysis on IgGs, notably involving site-directed mutagenesis to eliminate protease-susceptible sites or the in situ mitigation of host protease activities to minimize antibody processing in the cell secretory pathway. We here characterized the degradation profile of H10, a human tumour-targeting monoclonal IgG, in leaves of Nicotiana benthamiana also expressing the human serine protease inhibitor α1-antichymotrypsin or the cysteine protease inhibitor tomato cystatin SlCYS8. Leaf extracts revealed consistent fragmentation patterns for the recombinant antibody regardless of leaf age and a strong protective effect of SlCYS8 in specific regions of the heavy chain domains. As shown using an antigen-binding ELISA and LC-MS/MS analysis of antibody fragments, SlCYS8 had positive effects on both the amount of fully-assembled antibody purified from leaf tissue and the stability of biologically active antibody fragments containing the heavy chain Fc domain. Our data confirm the potential of Cys protease inhibitors as convenient antibody-stabilizing expression partners to increase the quality of therapeutic antibodies in plant protein biofactories. PMID:27893815

A combination of SILAC and nucleotide acyl phosphate labelling reveals unexpected targets of the Rsk inhibitor BI-D1870.

PubMed

Edgar, Alexander J; Trost, Matthias; Watts, Colin; Zaru, Rossana

2014-02-01

Protein kinase inhibitors frequently have interesting effects that cannot be fully ascribed to the intended target kinase(s) but identifying additional targets that might explain the effects is not straightforward. By comparing two different inhibitors of the Rsk (p90 ribosomal S6 kinase) kinases, we found that the increasingly used compound BI-D1870 had biological effects in murine DCs (dendritic cells) that could not be solely ascribed to Rsk or other documented targets. We assessed the ability of BI-D1870 and a second Rsk inhibitor, BIX 02565 to protect enzyme active sites from reaction with biotinylated nucleotide acyl phosphates. Using SILAC (stable isotope labelling by amino acids in cell culture)-labelled DC lysates as a source of enzyme targets, we identify several kinases that interact with BI-D1870 but not with BIX 02565. We confirmed that these kinases, including Slk, Lok and Mst1, are inhibited by BI-D1870 but to a much lesser extent by BIX 02565 and that phosphorylation of some of their substrates is blocked by BI-D1870 in living cells. Our results suggest that the BI-D1870 inhibitor should be used with caution. The SILAC-based methodology we used should be useful for further comparative unbiased profiling of the target spectrum of kinase inhibitors with interesting biological effects under conditions that closely mimic those found in cells. © 2014 The author(s).

Immune checkpoint inhibitors and targeted therapies for metastatic melanoma: A network meta-analysis.

PubMed

Pasquali, Sandro; Chiarion-Sileni, Vanna; Rossi, Carlo Riccardo; Mocellin, Simone

2017-03-01

Immune checkpoint inhibitors and targeted therapies, two new class of drugs for treatment of metastatic melanoma, have not been compared in randomized controlled trials (RCT). We quantitatively summarized the evidence and compared immune and targeted therapies in terms of both efficacy and toxicity. A comprehensive search for RCTs of immune checkpoint inhibitors and targeted therapies was conducted to August 2016. Using a network meta-analysis approach, treatments were compared with each other and ranked based on their effectiveness (as measured by the impact on progression-free survival [PFS]) and acceptability (the inverse of high grade toxicity). Twelve RCTs enrolling 6207 patients were included. Network meta-analysis generated 15 comparisons. Combined BRAF and MEK inhibitors were associated with longer PFS as compared to anti-CTLA4 (HR: 0.22; 95% confidence interval [CI]: 0.12-0.41) and anti-PD1 antibodies alone (HR: 0.38; CI: 0.20-0.72). However, anti-PD1 monoclonal antibodies were less toxic than anti-CTLA4 monoclonal antibodies (RR: 0.65; CI: 0.40-0.78) and their combination significantly increased toxicity compared to either single agent anti-CTLA4 (RR: 2.06; CI: 1.45-2.93) or anti-PD1 monoclonal antibodies (RR: 3.67; CI: 2.27-5.96). Consistently, ranking analysis suggested that the combination of targeted therapies is the most effective strategy, whereas single agent anti-PD1 antibodies have the best acceptability. The GRADE level of evidence quality for these findings was moderate to low. The simultaneous inhibition of BRAF and MEK appears the most effective treatment for melanomas harboring BRAF V600 mutation, although anti-PD1 antibodies appear to be less toxic. Further research is needed to increase the quality of evidence. Copyright © 2017 Elsevier Ltd. All rights reserved.

Targeting protein-protein interactions with trimeric ligands: high affinity inhibitors of the MAGUK protein family.

PubMed

Nissen, Klaus B; Haugaard-Kedström, Linda M; Wilbek, Theis S; Nielsen, Line S; Åberg, Emma; Kristensen, Anders S; Bach, Anders; Jemth, Per; Strømgaard, Kristian

2015-01-01

PDZ domains in general, and those of PSD-95 in particular, are emerging as promising drug targets for diseases such as ischemic stroke. We have previously shown that dimeric ligands that simultaneously target PDZ1 and PDZ2 of PSD-95 are highly potent inhibitors of PSD-95. However, PSD-95 and the related MAGUK proteins contain three consecutive PDZ domains, hence we envisioned that targeting all three PDZ domains simultaneously would lead to more potent and potentially more specific interactions with the MAGUK proteins. Here we describe the design, synthesis and characterization of a series of trimeric ligands targeting all three PDZ domains of PSD-95 and the related MAGUK proteins, PSD-93, SAP-97 and SAP-102. Using our dimeric ligands targeting the PDZ1-2 tandem as starting point, we designed novel trimeric ligands by introducing a PDZ3-binding peptide moiety via a cysteine-derivatized NPEG linker. The trimeric ligands generally displayed increased affinities compared to the dimeric ligands in fluorescence polarization binding experiments and optimized trimeric ligands showed low nanomolar inhibition towards the four MAGUK proteins, thus being the most potent inhibitors described. Kinetic experiments using stopped-flow spectrometry showed that the increase in affinity is caused by a decrease in the dissociation rate of the trimeric ligand as compared to the dimeric ligands, likely reflecting the lower probability of simultaneous dissociation of all three PDZ ligands. Thus, we have provided novel inhibitors of the MAGUK proteins with exceptionally high affinity, which can be used to further elucidate the therapeutic potential of these proteins.

Genetic Pathway of HIV-1 Resistance to Novel Fusion Inhibitors Targeting the Gp41 Pocket

PubMed Central

Su, Yang; Chong, Huihiui; Xiong, Shengwen; Qiao, Yuanyuan; Qiu, Zonglin

2015-01-01

ABSTRACT The peptide drug enfuvirtide (T20) is the only HIV-1 fusion inhibitor in clinical use, but it easily induces drug resistance, calling for new strategies for developing effective drugs. On the basis of the M-T hook structure, we recently developed highly potent short-peptide HIV-1 fusion inhibitors (MTSC22 and HP23), which mainly target the conserved gp41 pocket and possess high genetic barriers to resistance. Here, we focused on the selection and characterization of HIV-1 escape mutants of MTSC22, which revealed new resistance pathways and mechanisms. Two mutations (E49K and L57R) located at the inhibitor-binding site and two mutations (N126K and E136G) located at the C-terminal heptad repeat region of gp41 were identified as conferring high resistance either singly or in combination. While E49K reduced the C-terminal binding of inhibitors via an electrostatic repulsion, L57R dramatically disrupted the N-terminal binding of M-T hook structure and pocket-binding domain. Unlike E49K and N126K, which enhanced the stability of the endogenous viral six-helical bundle core (6-HB), L57R and E136G conversely destabilized the 6-HB structure. We also demonstrated that both primary and secondary mutations caused the structural changes in 6-HB and severely impaired the capability for HIV-1 entry. Collectively, our data provide novel insights into the mechanisms of short-peptide fusion inhibitors targeting the gp41 pocket site and help increase our understanding of the structure and function of gp41 and HIV-1 evolution. IMPORTANCE The deep pocket on the N-trimer of HIV-1 gp41 has been considered an ideal drug target because of its high degree of conservation and essential role in viral entry. Short-peptide fusion inhibitors, which contain an M-T hook structure and mainly target the pocket site, show extremely high binding and inhibitory activities as well as high genetic barriers to resistance. In this study, the HIV-1 mutants resistant to MTSC22 were selected and

N-glycans of Human Protein C Inhibitor: Tissue-Specific Expression and Function

PubMed Central

Engström, Åke; Sooriyaarachchi, Sanjeewani; Ubhayasekera, Wimal; Hreinsson, Julius; Wånggren, Kjell; Clark, Gary F.; Dell, Anne; Schedin-Weiss, Sophia

2011-01-01

Protein C inhibitor (PCI) is a serpin type of serine protease inhibitor that is found in many tissues and fluids in human, including blood plasma, seminal plasma and urine. This inhibitor displays an unusually broad protease specificity compared with other serpins. Previous studies have shown that the N-glycan(s) and the NH2-terminus affect some blood-related functions of PCI. In this study, we have for the first time determined the N-glycan profile of seminal plasma PCI, by mass spectrometry. The N-glycan structures differed markedly compared with those of both blood-derived and urinary PCI, providing evidence that the N-glycans of PCI are expressed in a tissue-specific manner. The most abundant structure (m/z 2592.9) had a composition of Fuc3Hex5HexNAc4, consistent with a core fucosylated bi-antennary glycan with terminal Lewisx. A major serine protease in semen, prostate specific antigen (PSA), was used to evaluate the effects of N-glycans and the NH2-terminus on a PCI function related to the reproductive tract. Second-order rate constants for PSA inhibition by PCI were 4.3±0.2 and 4.1±0.5 M−1s−1 for the natural full-length PCI and a form lacking six amino acids at the NH2-terminus, respectively, whereas these constants were 4.8±0.1 and 29±7 M−1s−1 for the corresponding PNGase F-treated forms. The 7–8-fold higher rate constants obtained when both the N-glycans and the NH2-terminus had been removed suggest that these structures jointly affect the rate of PSA inhibition, presumably by together hindering conformational changes of PCI required to bind to the catalytic pocket of PSA. PMID:22205989

PIM kinases as therapeutic targets against advanced melanoma

PubMed Central

Shannan, Batool; Watters, Andrea; Chen, Quan; Mollin, Stefan; Dörr, Markus; Meggers, Eric; Xu, Xiaowei; Gimotty, Phyllis A.; Perego, Michela; Li, Ling; Benci, Joseph; Krepler, Clemens; Brafford, Patricia; Zhang, Jie; Wei, Zhi; Zhang, Gao; Liu, Qin; Yin, Xiangfan; Nathanson, Katherine L.; Herlyn, Meenhard; Vultur, Adina

2016-01-01

Therapeutic strategies for the treatment of metastatic melanoma show encouraging results in the clinic; however, not all patients respond equally and tumor resistance still poses a challenge. To identify novel therapeutic targets for melanoma, we screened a panel of structurally diverse organometallic inhibitors against human-derived normal and melanoma cells. We observed that a compound that targets PIM kinases (a family of Ser/Thr kinases) preferentially inhibited melanoma cell proliferation, invasion, and viability in adherent and three-dimensional (3D) melanoma models. Assessment of tumor tissue from melanoma patients showed that PIM kinases are expressed in pre- and post-treatment tumors, suggesting PIM kinases as promising targets in the clinic. Using knockdown studies, we showed that PIM1 contributes to melanoma cell proliferation and tumor growth in vivo; however, the presence of PIM2 and PIM3 could also influence the outcome. The inhibition of all PIM isoforms using SGI-1776 (a clinically-available PIM inhibitor) reduced melanoma proliferation and survival in preclinical models of melanoma. This was potentiated in the presence of the BRAF inhibitor PLX4720 and in the presence of PI3K inhibitors. Our findings suggest that PIM inhibitors provide promising additions to the targeted therapies available to melanoma patients. PMID:27448973

NADPH oxidase inhibitors: a patent review.

PubMed

Kim, Jung-Ae; Neupane, Ganesh Prasad; Lee, Eung Seok; Jeong, Byeong-Seon; Park, Byung Chul; Thapa, Pritam

2011-08-01

NADPH oxidases, a family of multi-subunit enzyme complexes, catalyze the production of reactive oxygen species (ROS), which may contribute to the pathogenesis of a variety of diseases. In addition to the first NADPH oxidase found in phagocytes, four non-phagocytic NADPH oxidase isoforms have been identified, which all differ in their catalytic subunit (Nox1-5) and tissue distribution. This paper provides a comprehensive review of the patent literature on NADPH oxidase inhibitors, small molecule Nox inhibitors, peptides and siRNAs. Since each member of the NADPH oxidase family has great potential as a therapeutic target, several different compounds have been registered as NADPH oxidase inhibitors in the patent literature. As yet, none have gone through clinical trials, and some have not completed preclinical trials, including safety and specificity evaluation. Recently, small molecule pyrazolopyridine and triazolopyrimidine derivatives have been submitted as potent NADPH oxidase inhibitors and reported as first-in-class inhibitors for idiopathic pulmonary fibrosis and acute stroke, respectively. Further clinical efficacy and safety data are warranted to prove their actual clinical utility.

DYRK1B as therapeutic target in Hedgehog/GLI-dependent cancer cells with Smoothened inhibitor resistance

PubMed Central

Gruber, Wolfgang; Hutzinger, Martin; Elmer, Dominik Patrick; Parigger, Thomas; Sternberg, Christina; Cegielkowski, Lukasz; Zaja, Mirko; Leban, Johann; Michel, Susanne; Hamm, Svetlana; Vitt, Daniel; Aberger, Fritz

2016-01-01

A wide range of human malignancies displays aberrant activation of Hedgehog (HH)/GLI signaling, including cancers of the skin, brain, gastrointestinal tract and hematopoietic system. Targeting oncogenic HH/GLI signaling with small molecule inhibitors of the essential pathway effector Smoothened (SMO) has shown remarkable therapeutic effects in patients with advanced and metastatic basal cell carcinoma. However, acquired and de novo resistance to SMO inhibitors poses severe limitations to the use of SMO antagonists and urgently calls for the identification of novel targets and compounds. Here we report on the identification of the Dual-Specificity-Tyrosine-Phosphorylation-Regulated Kinase 1B (DYRK1B) as critical positive regulator of HH/GLI signaling downstream of SMO. Genetic and chemical inhibition of DYRK1B in human and mouse cancer cells resulted in marked repression of HH signaling and GLI1 expression, respectively. Importantly, DYRK1B inhibition profoundly impaired GLI1 expression in both SMO-inhibitor sensitive and resistant settings. We further introduce a novel small molecule DYRK1B inhibitor, DYRKi, with suitable pharmacologic properties to impair SMO-dependent and SMO-independent oncogenic GLI activity. The results support the use of DYRK1B antagonists for the treatment of HH/GLI-associated cancers where SMO inhibitors fail to demonstrate therapeutic efficacy. PMID:26784250

Necroptosis inhibitors as therapeutic targets in inflammation mediated disorders - a review of the current literature and patents.

PubMed

Kopalli, Spandana Rajendra; Kang, Tae-Bong; Koppula, Sushruta

2016-11-01

Recent studies have shown substantial interplay between the apoptosis and necroptosis pathways. Necroptosis, a form of programmed cell death, has been found to stimulate the immune system contributing to the pathophysiology of several inflammation-mediated disorders. Determining the contribution of necroptotic signaling pathways to inflammation may lead to the development of selective and specific molecular target implicated necroptosis inhibitors. Areas covered: This review summarizes the recently published and patented necroptosis inhibitors as therapeutic targets in inflammation-mediated disorders. The role of several necroptosis inhibitors, focusing on specific signaling molecules, was discussed with particular attention to inflammation-mediated disorders. Data was obtained from Espacenet®, WIPO®, USPTO® patent websites, and other relevant sources (2006-2016). Expert opinion: Necroptosis inhibitors hold promise for treatment of inflammation-mediated clinical conditions in which necroptotic cell death plays a major role. Although necroptosis inhibitors reviewed in this survey showed inhibitory effects against several inflammation-mediated disorders, only a few have passed to the stage of clinical testing and need extensive research for therapeutic practice. Revisiting the existing drugs and developing novel necroptosis inhibiting agents as well as understanding their mechanism are essential. A detailed study of necroptosis function in animal models of inflammation may provide us an alternative strategy for the development of drug-like necroptosis inhibitors.

Magnetoferritin nanoparticles for targeting and visualizing tumour tissues

NASA Astrophysics Data System (ADS)

Fan, Kelong; Cao, Changqian; Pan, Yongxin; Lu, Di; Yang, Dongling; Feng, Jing; Song, Lina; Liang, Minmin; Yan, Xiyun

2012-07-01

Engineered nanoparticles have been used to provide diagnostic, therapeutic and prognostic information about the status of disease. Nanoparticles developed for these purposes are typically modified with targeting ligands (such as antibodies, peptides or small molecules) or contrast agents using complicated processes and expensive reagents. Moreover, this approach can lead to an excess of ligands on the nanoparticle surface, and this causes non-specific binding and aggregation of nanoparticles, which decreases detection sensitivity. Here, we show that magnetoferritin nanoparticles (M-HFn) can be used to target and visualize tumour tissues without the use of any targeting ligands or contrast agents. Iron oxide nanoparticles are encapsulated inside a recombinant human heavy-chain ferritin (HFn) protein shell, which binds to tumour cells that overexpress transferrin receptor 1 (TfR1). The iron oxide core catalyses the oxidation of peroxidase substrates in the presence of hydrogen peroxide to produce a colour reaction that is used to visualize tumour tissues. We examined 474 clinical specimens from patients with nine types of cancer and verified that these nanoparticles can distinguish cancerous cells from normal cells with a sensitivity of 98% and specificity of 95%.

Computer-assisted identification of novel small molecule inhibitors targeting GLUT1

NASA Astrophysics Data System (ADS)

Wan, Zhining; Li, Xin; Sun, Rong; Li, Yuanyuan; Wang, Xiaoyun; Li, Xinru; Rong, Li; Shi, Zheng; Bao, Jinku

2015-12-01

Glucose transporters (GLUTs) are the main carriers of glucose that facilitate the diffusion of glucose in mammalian cells, especially GLUT1. Notably, GLUT1 is a rate-limiting transporter for glucose uptake, and its overexpression is a common characteristic in most cancers. Thus, the inhibition of GLUT1 by novel small compounds to lower glucose levels for cancer cells has become an emerging strategy. Herein, we employed high-throughput screening approaches to identify potential inhibitors against the sugar-binding site of GLUT1. Firstly, molecular docking screening was launched against the specs products, and three molecules (ZINC19909927, ZINC19908826, and ZINC19815451) were selected as candidate GLUT1 inhibitors for further analysis. Then, taking the initial ligand β-NG as a reference, molecular dynamic (MD) simulations and molecular mechanics/generalized born surface area (MM/GBSA) method were applied to evaluate the binding stability and affinity of the three candidates towards GLUT1. Finally, we found that ZINC19909927 might have the highest affinity to occupy the binding site of GLUT1. Meanwhile, energy decomposition analysis identified several residues located in substrate-binding site that might provide clues for future inhibitor discovery towards GLUT1. Taken together, these results in our study may provide valuable information for identifying new inhibitors targeting GLUT1-mediated glucose transport and metabolism for cancer therapeutics.

PREDICTING THE RISKS OF NEUROTOXIC VOLATILE ORGANIC COMPOUNDS BASED ON TARGET TISSUE DOSE.

EPA Science Inventory

Quantitative exposure-dose-response models relate the external exposure of a substance to the dose in the target tissue, and then relate the target tissue dose to production of adverse outcomes. We developed exposure-dose-response models to describe the affects of acute exposure...

Caspase-3 inhibitor prevents the apoptosis of brain tissue in rats with acute cerebral infarction.

PubMed

Sun, Yuhua; Xu, Yuming; Geng, Lijiao

2015-07-01

The aim of the present study was to investigate the effect of the caspase-3 inhibitor z-DEVD-fmk on the apoptosis of the brain tissues of rats with acute cerebral infarction. Middle cerebral artery occlusion was used to establish a rat model of infarction, and the rats were randomly divided into a sham group (n=15), model group (n=15) and treatment group (n=15). z-DEVD-fmk (2.5 µg/kg) was injected into the intracranial artery of rats in the treatment group, while the same volume of phosphate-buffered saline solution was administered to the rats of the sham and model groups. After 48 h, all rats were sacrificed and their brain tissues were removed. The caspase-3 mRNA level, protein level and activity, brain cell apoptosis index and infarction scope of the three groups were analyzed. Neurological impairment was also assessed. At 48 h after model establishment, the caspase-3 mRNA and protein levels in the brain tissues of the model group were significantly higher than those of the sham group, and those in the treatment group were significantly lower than those in the model group (P<0.05); however, they remained significantly higher than those in the sham group. Caspase-3 activity in the model group was significantly higher than that in the sham group, and treatment with the caspase-3 inhibitor significantly reduced caspase-3 activity compared with that in the model group (P<0.05). The apoptosis index and infarction scope in the model and treatment groups were significantly increased compared with those in the sham group, and were significantly lower in the treatment group than in the model group (P<0.05). The neurological impairment of rats in the model and treatment groups was increased significantly compared with that in the sham group, and the treatment group exhibited a significantly lower level of neurological impairment than the model group (P<0.05). In conclusion, the caspase-3 inhibitor z-DEVD-fmk effectively inhibited apoptosis and delayed the necrosis of

In Vitro Targeted Photodynamic Therapy with a Pyropheophorbide-a Conjugated Inhibitor of Prostate Specific Membrane Antigen

PubMed Central

Liu, Tiancheng; Wu, Lisa Y.; Choi, Joseph K.; Berkman, Clifford E.

2009-01-01

BACKROUND The lack of specific delivery of photosensitizers (PSs), represents a significant limitation of photodynamic therapy (PDT) of cancer. The biomarker prostate-specific membrane antigen (PSMA) has attracted considerable attention as a target for imaging and therapeutic applications for prostate cancer. Although recent efforts have been made to conjugate inhibitors of PSMA with imaging agents, there have been no reports on photosensitizer-conjugated PSMA inhibitors for targeted PDT of prostate cancer. The present study focuses on the use of a PSMA inhibitor-conjugate of pyropheophorbide-a (Ppa-conjugate 2) for targeted PDT to achieve apoptosis in PSMA+ LNCaP cells. METHODS Confocal laser scanning microscopy with a combination of nuclear staining and immunofluorescence methods were employed to monitor the specific imaging and PDT-mediated apoptotic effects on PSMA-positive LNCaP and PSMA-negative (PC-3) cells. RESULTS Our results demonstrated that PDT-mediated effects by Ppa-conjugate 2 were specific to LNCaP cells, but not PC-3 cells. Cell permeability was detected as early as 2 h by HOE33342/PI double-staining, becoming more intense by 4 h. Evidence for the apoptotic caspase cascade being activated was based on the appearance of PARP p85 fragment. TUNEL assay detected DNA fragmentation 16 h post-PDT, confirming apoptotic events. CONCLUSIONS Cell permeability by HOE33342/PI double-staining as well as PARP p85 fragment and TUNEL assays confirm cellular apoptosis in PSMA+ cells when treated with PS-inhibitor conjugate 2 and subsequently irradiated. It is expected that the PSMA targeting small-molecule of this conjugate can serve as a delivery vehicle for PDT and other therapeutic applications for prostate cancer. PMID:19142895

Metallochaperone UreG serves as a new target for design of urease inhibitor: A novel strategy for development of antimicrobials.

PubMed

Yang, Xinming; Koohi-Moghadam, Mohamad; Wang, Runming; Chang, Yuen-Yan; Woo, Patrick C Y; Wang, Junwen; Li, Hongyan; Sun, Hongzhe

2018-01-01

Urease as a potential target of antimicrobial drugs has received considerable attention given its versatile roles in microbial infection. Development of effective urease inhibitors, however, is a significant challenge due to the deeply buried active site and highly specific substrate of a bacterial urease. Conventionally, urease inhibitors are designed by either targeting the active site or mimicking substrate of urease, which is not efficient. Up to now, only one effective inhibitor-acetohydroxamic acid (AHA)-is clinically available, but it has adverse side effects. Herein, we demonstrate that a clinically used drug, colloidal bismuth subcitrate, utilizes an unusual way to inhibit urease activity, i.e., disruption of urease maturation process via functional perturbation of a metallochaperone, UreG. Similar phenomena were also observed in various pathogenic bacteria, suggesting that UreG may serve as a general target for design of new types of urease inhibitors. Using Helicobacter pylori UreG as a showcase, by virtual screening combined with experimental validation, we show that two compounds targeting UreG also efficiently inhibited urease activity with inhibitory concentration (IC)50 values of micromolar level, resulting in attenuated virulence of the pathogen. We further demonstrate the efficacy of the compounds in a mammalian cell infection model. This study opens up a new opportunity for the design of more effective urease inhibitors and clearly indicates that metallochaperones involved in the maturation of important microbial metalloenzymes serve as new targets for devising a new type of antimicrobial drugs.

Sepsis-Induced Coagulation in the Baboon Lung Is Associated with Decreased Tissue Factor Pathway Inhibitor

PubMed Central

Tang, Haiwang; Ivanciu, Lacramioara; Popescu, Narcis; Peer, Glenn; Hack, Erik; Lupu, Cristina; Taylor, Fletcher B.; Lupu, Florea

2007-01-01

Increased tissue factor (TF)-dependent procoagulant activity in sepsis may be partly due to decreased expression or function of tissue factor pathway inhibitor (TFPI). To test this hypothesis, baboons were infused with live Escherichia coli and sacrificed after 2, 8, or 24 hours. Confocal and electron microscopy revealed increased leukocyte infiltration and fibrin deposition in the intravascular and interstitial compartments. Large amounts of TF were detected by immunostaining in leukocytes and platelet-rich microthrombi. TF induction was documented by quantitative reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay, and coagulation assays. Lung-associated TFPI antigen and mRNA decreased during sepsis, and TFPI activity diminished abruptly at 2 hours. Blocking antibodies against TFPI increased fibrin deposition in septic baboon lungs, suggesting that TF-dependent coagulation might be aggravated by reduced endothelial TFPI. Decreased TFPI activity coincided with the release of tissue plasminogen activator and the peak of plasmin generation, suggesting that TFPI could undergo proteolytic inactivation by plasmin. Enhanced plasmin produced in septic baboons by infusion of blocking antibodies against plasminogen activator inhibitor-1 led to decreased lung-associated TFPI and unforeseen massive fibrin deposition. We conclude that activation of TF-driven coagulation not adequately countered by TFPI may underlie the widespread thrombotic complications of sepsis. PMID:17640967

Alternative Polyadenylation Directs Tissue-Specific miRNA Targeting in Caenorhabditis elegans Somatic Tissues

PubMed Central

Blazie, Stephen M.; Geissel, Heather C.; Wilky, Henry; Joshi, Rajan; Newbern, Jason; Mangone, Marco

2017-01-01

mRNA expression dynamics promote and maintain the identity of somatic tissues in living organisms; however, their impact in post-transcriptional gene regulation in these processes is not fully understood. Here, we applied the PAT-Seq approach to systematically isolate, sequence, and map tissue-specific mRNA from five highly studied Caenorhabditis elegans somatic tissues: GABAergic and NMDA neurons, arcade and intestinal valve cells, seam cells, and hypodermal tissues, and studied their mRNA expression dynamics. The integration of these datasets with previously profiled transcriptomes of intestine, pharynx, and body muscle tissues, precisely assigns tissue-specific expression dynamics for 60% of all annotated C. elegans protein-coding genes, providing an important resource for the scientific community. The mapping of 15,956 unique high-quality tissue-specific polyA sites in all eight somatic tissues reveals extensive tissue-specific 3′untranslated region (3′UTR) isoform switching through alternative polyadenylation (APA) . Almost all ubiquitously transcribed genes use APA and harbor miRNA targets in their 3′UTRs, which are commonly lost in a tissue-specific manner, suggesting widespread usage of post-transcriptional gene regulation modulated through APA to fine tune tissue-specific protein expression. Within this pool, the human disease gene C. elegans orthologs rack-1 and tct-1 use APA to switch to shorter 3′UTR isoforms in order to evade miRNA regulation in the body muscle tissue, resulting in increased protein expression needed for proper body muscle function. Our results highlight a major positive regulatory role for APA, allowing genes to counteract miRNA regulation on a tissue-specific basis. PMID:28348061

Alternative Polyadenylation Directs Tissue-Specific miRNA Targeting in Caenorhabditis elegans Somatic Tissues.

PubMed

Blazie, Stephen M; Geissel, Heather C; Wilky, Henry; Joshi, Rajan; Newbern, Jason; Mangone, Marco

2017-06-01

mRNA expression dynamics promote and maintain the identity of somatic tissues in living organisms; however, their impact in post-transcriptional gene regulation in these processes is not fully understood. Here, we applied the PAT-Seq approach to systematically isolate, sequence, and map tissue-specific mRNA from five highly studied Caenorhabditis elegans somatic tissues: GABAergic and NMDA neurons, arcade and intestinal valve cells, seam cells, and hypodermal tissues, and studied their mRNA expression dynamics. The integration of these datasets with previously profiled transcriptomes of intestine, pharynx, and body muscle tissues, precisely assigns tissue-specific expression dynamics for 60% of all annotated C. elegans protein-coding genes, providing an important resource for the scientific community. The mapping of 15,956 unique high-quality tissue-specific polyA sites in all eight somatic tissues reveals extensive tissue-specific 3'untranslated region (3'UTR) isoform switching through alternative polyadenylation (APA) . Almost all ubiquitously transcribed genes use APA and harbor miRNA targets in their 3'UTRs, which are commonly lost in a tissue-specific manner, suggesting widespread usage of post-transcriptional gene regulation modulated through APA to fine tune tissue-specific protein expression. Within this pool, the human disease gene C. elegans orthologs rack-1 and tct-1 use APA to switch to shorter 3'UTR isoforms in order to evade miRNA regulation in the body muscle tissue, resulting in increased protein expression needed for proper body muscle function. Our results highlight a major positive regulatory role for APA, allowing genes to counteract miRNA regulation on a tissue-specific basis. Copyright © 2017 Blazie et al.

The Future of Molecular Analysis in Melanoma: Diagnostics to Direct Molecularly Targeted Therapy.

PubMed

Akabane, Hugo; Sullivan, Ryan J

2016-02-01

Melanoma is a malignancy of pigment-producing cells that is driven by a variety of genetic mutations and aberrations. In most cases, this leads to upregulation of the mitogen-activated protein kinase (MAPK) pathway through activating mutations of upstream mediators of the pathway including BRAF and NRAS. With the advent of effective MAPK pathway inhibitors, including the US FDA-approved BRAF inhibitors vemurafenib and dabrafenib and MEK inhibitor trametinib, molecular analysis has become an integral part of the care of patients with metastatic melanoma. In this article, the key molecular targets and strategies to inhibit these targets therapeutically are presented, and the techniques of identifying these targets, in both tissue and blood, are discussed.

Cell Density Affects the Detection of Chk1 Target Engagement by the Selective Inhibitor V158411.

PubMed

Geneste, Clara C; Massey, Andrew J

2018-02-01

Understanding drug target engagement and the relationship to downstream pharmacology is critical for drug discovery. Here we have evaluated target engagement of Chk1 by the small-molecule inhibitor V158411 using two different target engagement methods (autophosphorylation and cellular thermal shift assay [CETSA]). Target engagement measured by these methods was subsequently related to Chk1 inhibitor-dependent pharmacology. Inhibition of autophosphorylation was a robust method for measuring V158411 Chk1 target engagement. In comparison, while target engagement determined using CETSA appeared robust, the V158411 CETSA target engagement EC 50 values were 43- and 19-fold greater than the autophosphorylation IC 50 values. This difference was attributed to the higher cell density in the CETSA assay configuration. pChk1 (S296) IC 50 values determined using the CETSA assay conditions were 54- and 33-fold greater than those determined under standard conditions and were equivalent to the CETSA EC 50 values. Cellular conditions, especially cell density, influenced the target engagement of V158411 for Chk1. The effects of high cell density on apparent compound target engagement potency should be evaluated when using target engagement assays that necessitate high cell densities (such as the CETSA conditions used in this study). In such cases, the subsequent relation of these data to downstream pharmacological changes should therefore be interpreted with care.

Epigenetic Mechanisms Regulating Adaptive Responses to Targeted Kinase Inhibitors in Cancer.

PubMed

Angus, Steven P; Zawistowski, Jon S; Johnson, Gary L

2018-01-06

Although targeted inhibition of oncogenic kinase drivers has achieved remarkable patient responses in many cancers, the development of resistance has remained a significant challenge. Numerous mechanisms have been identified, including the acquisition of gatekeeper mutations, activating pathway mutations, and copy number loss or gain of the driver or alternate nodes. These changes have prompted the development of kinase inhibitors with increased selectivity, use of second-line therapeutics to overcome primary resistance, and combination treatment to forestall resistance. In addition to genomic resistance mechanisms, adaptive transcriptional and signaling responses seen in tumors are gaining appreciation as alterations that lead to a phenotypic state change-often observed as an epithelial-to-mesenchymal shift or reversion to a cancer stem cell-like phenotype underpinned by remodeling of the epigenetic landscape. This epigenomic modulation driving cell state change is multifaceted and includes modulation of repressive and activating histone modifications, DNA methylation, enhancer remodeling, and noncoding RNA species. Consequently, the combination of kinase inhibitors with drugs targeting components of the transcriptional machinery and histone-modifying enzymes has shown promise in preclinical and clinical studies. Here, we review mechanisms of resistance to kinase inhibition in cancer, with special emphasis on the rewired kinome and transcriptional signaling networks and the potential vulnerabilities that may be exploited to overcome these adaptive signaling changes.

Simultaneous expression of tissue factor and tissue factor pathway inhibitor by human monocytes. A potential mechanism for localized control of blood coagulation

PubMed Central

1994-01-01

Cells of monocytic lineage can initiate extravascular fibrin deposition via expression of blood coagulation mediators. This report is about experiments on three mechanisms with the potential to modulate monocyte- initiated coagulation. Monocyte procoagulant activity was examined as a function of lipid cofactor, protein cofactor, and specific inhibitor expression during short-term culture in vitro. Lipid cofactor activity was measured as the initial rate of factor X activation by intrinsic- pathway components, the assembly of which depends on this cofactor. Lipid cofactor activity levels changed by < 30% during 48-h culture. Protein cofactor, i.e., tissue factor (TF) antigen was measured by enzyme immunoassay. It increased from 461 pg/ml to a maximum value of 3,550 pg/ml at 24 h and remained at 70% of this value. Specific TF activity, measured as factor VII-dependent factor X activation rate, decreased from 54 to 18 nM FXa/min between 24 and 48 h. TF activity did not correlate well with either lipid cofactor or TF protein levels. In contrast, the decrease in TF activity coincided in time with maximal expression of tissue factor pathway inhibitor (TFPI) mRNA, which was determined using reverse transcriptase polymerase chain reaction (RT- PCR), and with maximal TFPI protein levels measured by immunoassay. The number of mRNA copies coding for TFPI and TF in freshly isolated blood monocytes were 46 and 20 copies/cells, respectively. These values increased to 220 and 63 copies/cell during short-term cell culture in the presence of endotoxin. Results demonstrate concomitant expression by monocytes of genes coding for both the essential protein cofactor and the specific inhibitor of the extrinsic coagulation pathway. Together with functional and antigenic analyses, they also imply that the initiation of blood clotting by extravascular monocyte/macrophages can be modulated locally by TFPI independently of plasma sources of the inhibitor. PMID:8195712

Pharmacokinetic drivers of toxicity for basic molecules: Strategy to lower pKa results in decreased tissue exposure and toxicity for a small molecule Met inhibitor

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

Diaz, Dolores, E-mail: diaz.dolores@gene.com; Ford, Kevin A.; Hartley, Dylan P.

Several toxicities are clearly driven by free drug concentrations in plasma, such as toxicities related to on-target exaggerated pharmacology or off-target pharmacological activity associated with receptors, enzymes or ion channels. However, there are examples in which organ toxicities appear to correlate better with total drug concentrations in the target tissues, rather than with free drug concentrations in plasma. Here we present a case study in which a small molecule Met inhibitor, GEN-203, with significant liver and bone marrow toxicity in preclinical species was modified with the intention of increasing the safety margin. GEN-203 is a lipophilic weak base as demonstratedmore » by its physicochemical and structural properties: high LogD (distribution coefficient) (4.3) and high measured pKa (7.45) due to the basic amine (N-ethyl-3-fluoro-4-aminopiperidine). The physicochemical properties of GEN-203 were hypothesized to drive the high distribution of this compound to tissues as evidenced by a moderately-high volume of distribution (Vd > 3 l/kg) in mouse and subsequent toxicities of the compound. Specifically, the basicity of GEN-203 was decreased through addition of a second fluorine in the 3-position of the aminopiperidine to yield GEN-890 (N-ethyl-3,3-difluoro-4-aminopiperidine), which decreased the volume of distribution of the compound in mouse (Vd = 1.0 l/kg), decreased its tissue drug concentrations and led to decreased toxicity in mice. This strategy suggests that when toxicity is driven by tissue drug concentrations, optimization of the physicochemical parameters that drive tissue distribution can result in decreased drug concentrations in tissues, resulting in lower toxicity and improved safety margins. -- Highlights: ► Lower pKa for a small molecule: reduced tissue drug levels and toxicity. ► New analysis tools to assess electrostatic effects and ionization are presented. ► Chemical and PK drivers of toxicity can be leveraged to improve safety.« less

The identification of new protein kinase inhibitors as targets in modern drug discovery.

PubMed

Akritopoulou-Zanze, Irini

2006-07-01

In recent years there has been great interest in developing protein kinase inhibitors as therapeutic agents for a variety of diseases. This article provides an overview on the history, development and validity of kinases as drug targets, as well as a description of kinase research, including its limitations, challenges and successes.

Isoprenoid Biosynthesis Inhibitors Targeting Bacterial Cell Growth.

PubMed

Desai, Janish; Wang, Yang; Wang, Ke; Malwal, Satish R; Oldfield, Eric

2016-10-06

We synthesized potential inhibitors of farnesyl diphosphate synthase (FPPS), undecaprenyl diphosphate synthase (UPPS), or undecaprenyl diphosphate phosphatase (UPPP), and tested them in bacterial cell growth and enzyme inhibition assays. The most active compounds were found to be bisphosphonates with electron-withdrawing aryl-alkyl side chains which inhibited the growth of Gram-negative bacteria (Acinetobacter baumannii, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa) at ∼1-4 μg mL -1 levels. They were found to be potent inhibitors of FPPS; cell growth was partially "rescued" by the addition of farnesol or overexpression of FPPS, and there was synergistic activity with known isoprenoid biosynthesis pathway inhibitors. Lipophilic hydroxyalkyl phosphonic acids inhibited UPPS and UPPP at micromolar levels; they were active (∼2-6 μg mL -1 ) against Gram-positive but not Gram-negative organisms, and again exhibited synergistic activity with cell wall biosynthesis inhibitors, but only indifferent effects with other inhibitors. The results are of interest because they describe novel inhibitors of FPPS, UPPS, and UPPP with cell growth inhibitory activities as low as ∼1-2 μg mL -1 . © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nonmelanoma Skin Cancers After Kidney Transplant: Our 15 Years of Experience With Mammalian Target of Rapamycin Inhibitors.

PubMed

Okut, Gokalp; Alp, Alper; Tatar, Erhan; Simsek, Cenk; Tugmen, Cem; Uslu, Adam

2017-02-01

We evaluated patients with nonmelanoma skin cancer after kidney transplant and the effects of immunosuppression reduction and switching to a mammalian target of rapamycin inhibitor drugs. Kidney transplant recipients were evaluated retrospectively from patient medical records (between January 2000 and December 2014). A 30% increase in serum creatinine was accepted as indicating renal failure progression. Of 18 patients included (mean follow-up 98 ± 66 mo), 7 (38.8%) had squamous cell carcinoma, 7 (38.8%) had Kaposi sarcoma, and 4 (22.2%) had basal cell carcinoma. At cancer diagnosis, average serum creatinine was 1.6 ± 0.7 mg/dL and proteinuria was 410 ± 766 mg/d. Immunosuppression regimen was changed in 15 patients (83.3%), with new regimen being a single-drug (only prednisolone) in 4 patients, double-drug in 6 patients, and triple-drug protocol in 8 patients. Eight patients were switched to a mammalian target of rapamycin inhibitor-based double (4 patients) or triple (4 patients) regimen. During follow-up after starting new treatment (average 46 ± 50 mo), 6 patients (33.3%) had progressive kidney failure (0 were receiving triple regimen). Those that progressed were using mammalian target of rapamycin inhibitor-based drugs relatively less (33% vs 50%), although often receiving a single-drug immunosuppression treatment (50% vs 8.3%). Three patients (33.3%) had acute rejection (2 receiving double and 1 receiving single immunosuppression treatment). Five patients (27.7%) had local recurrence of the primary tumor. Mammalian target of rapamycin inhibitor use was relatively less common in patients with tumor relapse (20% vs 46%). One patient died (heart failure), and 1 with chronic rejection returned to dialysis. Mammalian target of rapamycin inhibitorbased drugs could reduce local recurrence rate in kidney transplant recipients with nonmelanoma skin cancers. Aggressive reduction and/or cessation of immunosuppressive drugs after skin cancer can lead to graft

In vitro targeted photodynamic therapy with a pyropheophorbide--a conjugated inhibitor of prostate-specific membrane antigen.

PubMed

Liu, Tiancheng; Wu, Lisa Y; Choi, Joseph K; Berkman, Clifford E

2009-05-01

The lack of specific delivery of photosensitizers (PSs), represents a significant limitation of photodynamic therapy (PDT) of cancer. The biomarker prostate-specific membrane antigen (PSMA) has attracted considerable attention as a target for imaging and therapeutic applications for prostate cancer. Although recent efforts have been made to conjugate inhibitors of PSMA with imaging agents, there have been no reports on PS-conjugated PSMA inhibitors for targeted PDT of prostate cancer. The present study focuses on the use of a PSMA inhibitor-conjugate of pyropheophorbide-a (Ppa-conjugate 2) for targeted PDT to achieve apoptosis in PSMA+ LNCaP cells. Confocal laser scanning microscopy with a combination of nuclear staining and immunofluorescence methods were employed to monitor the specific imaging and PDT-mediated apoptotic effects on PSMA-positive LNCaP and PSMA-negative (PC-3) cells. Our results demonstrated that PDT-mediated effects by Ppa-conjugate 2 were specific to LNCaP cells, but not PC-3 cells. Cell permeability was detected as early as 2 hr by HOE33342/PI double staining, becoming more intense by 4 hr. Evidence for the apoptotic caspase cascade being activated was based on the appearance of poly-ADP-ribose polymerase (PARP) p85 fragment. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay detected DNA fragmentation 16 hr post-PDT, confirming apoptotic events. Cell permeability by HOE33342/PI double staining as well as PARP p85 fragment and TUNEL assays confirm cellular apoptosis in PSMA+ cells when treated with PS-inhibitor conjugate 2 and subsequently irradiated. It is expected that the PSMA targeting small-molecule of this conjugate can serve as a delivery vehicle for PDT and other therapeutic applications for prostate cancer. (c) 2009 Wiley-Liss, Inc.

GENE EXPRESSION PROFILING OF ACCESSIBLE SURROGATE TISSUES TO MONITOR MOLECULAR CHANGES IN INACCESSIBLE TARGET TISSUES FOLLOWING TOXICANT EXPOSURE

EPA Science Inventory

Gene Expression Profiling Of Accessible Surrogate Tissues To Monitor Molecular Changes In Inaccessible Target Tissues Following Toxicant Exposure
John C. Rockett, Chad R. Blystone, Amber K. Goetz, Rachel N. Murrell, Judith E. Schmid and David J. Dix
Reproductive Toxicology ...

Bruton's tyrosine kinase (BTK) inhibitors in clinical trials.

PubMed

Burger, Jan A

2014-03-01

BTK is a cytoplasmic, non-receptor tyrosine kinase that transmits signals from a variety of cell-surface molecules, including the B-cell receptor (BCR) and tissue homing receptors. Genetic BTK deletion causes B-cell immunodeficiency in humans and mice, making this kinase an attractive therapeutic target for B-cell disorders. The BTK inhibitor ibrutinib (PCI-32765, brand name: Imbruvica) demonstrated high clinical activity in B-cell malignancies, especially in patients with chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), and Waldenstrom's macroglobulinemia (WM). Therefore, ibrutinib was granted a 'breakthrough therapy' designation for these indications and was recently approved for the treatment of relapsed MCL by the U.S. Food and Drug Administration. Other BTK inhibitors in earlier clinical development include CC-292 (AVL-292), and ONO-4059. In CLL and MCL, ibrutinib characteristically induces redistribution of malignant B cells from tissue sites into the peripheral blood, along with rapid resolution of enlarged lymph nodes and a surge in lymphocytosis. With continuous ibrutinib therapy, growth- and survival-inhibitory activities of ibrutinib result in the normalization of lymphocyte counts and remissions in a majority of patients. This review discusses the clinical advances with BTK inhibitor therapy, as well as its pathophysiological basis, and outlines perspectives for future use of BTK inhibitors.

Tissue Kallikrein Inhibitors Based on the Sunflower Trypsin Inhibitor Scaffold – A Potential Therapeutic Intervention for Skin Diseases

PubMed Central

Chen, Wenjie; Kinsler, Veronica A.

2016-01-01

Tissue kallikreins (KLKs), in particular KLK5, 7 and 14 are the major serine proteases in the skin responsible for skin shedding and activation of inflammatory cell signaling. In the normal skin, their activities are controlled by an endogenous protein protease inhibitor encoded by the SPINK5 gene. Loss-of-function mutations in SPINK5 leads to enhanced skin kallikrein activities and cause the skin disease Netherton Syndrome (NS). We have been developing inhibitors based on the Sunflower Trypsin Inhibitor 1 (SFTI-1) scaffold, a 14 amino acids head-to-tail bicyclic peptide with a disulfide bond. To optimize a previously reported SFTI-1 analogue (I10H), we made five analogues with additional substitutions, two of which showed improved inhibition. We then combined those substitutions and discovered a variant (Analogue 6) that displayed dual inhibition of KLK5 (tryptic) and KLK7 (chymotryptic). Analogue 6 attained a tenfold increase in KLK5 inhibition potency with an Isothermal Titration Calorimetry (ITC) Kd of 20nM. Furthermore, it selectively inhibits KLK5 and KLK14 over seven other serine proteases. Its biological function was ascertained by full suppression of KLK5-induced Protease-Activated Receptor 2 (PAR-2) dependent intracellular calcium mobilization and postponement of Interleukin-8 (IL-8) secretion in cell model. Moreover, Analogue 6 permeates through the cornified layer of in vitro organotypic skin equivalent culture and inhibits protease activities therein, providing a potential drug lead for the treatment of NS. PMID:27824929

Rational optimization of drug-target residence time: Insights from inhibitor binding to the S. aureus FabI enzyme-product complex

PubMed Central

Chang, Andrew; Schiebel, Johannes; Yu, Weixuan; Bommineni, Gopal R.; Pan, Pan; Baxter, Michael V.; Khanna, Avinash; Sotriffer, Christoph A.; Kisker, Caroline; Tonge, Peter J.

2013-01-01

Drug-target kinetics has recently emerged as an especially important facet of the drug discovery process. In particular, prolonged drug-target residence times may confer enhanced efficacy and selectivity in the open in vivo system. However, the lack of accurate kinetic and structural data for series of congeneric compounds hinders the rational design of inhibitors with decreased off-rates. Therefore, we chose the Staphylococcus aureus enoyl-ACP reductase (saFabI) - an important target for the development of new anti-staphylococcal drugs - as a model system to rationalize and optimize the drug-target residence time on a structural basis. Using our new, efficient and widely applicable mechanistically informed kinetic approach, we obtained a full characterization of saFabI inhibition by a series of 20 diphenyl ethers complemented by a collection of 9 saFabI-inhibitor crystal structures. We identified a strong correlation between the affinities of the investigated saFabI diphenyl ether inhibitors and their corresponding residence times, which can be rationalized on a structural basis. Due to its favorable interactions with the enzyme, the residence time of our most potent compound exceeds 10 hours. In addition, we found that affinity and residence time in this system can be significantly enhanced by modifications predictable by a careful consideration of catalysis. Our study provides a blueprint for investigating and prolonging drug-target kinetics and may aid in the rational design of long-residence-time inhibitors targeting the essential saFabI enzyme. PMID:23697754

Kinetics of CLL cells in tissues and blood during therapy with the BTK inhibitor ibrutinib.

PubMed

Wodarz, Dominik; Garg, Naveen; Komarova, Natalia L; Benjamini, Ohad; Keating, Michael J; Wierda, William G; Kantarjian, Hagop; James, Danelle; O'Brien, Susan; Burger, Jan A

2014-06-26

The Bruton tyrosine kinase (BTK) inhibitor ibrutinib has excellent clinical activity in patients with chronic lymphocytic leukemia (CLL). Characteristically, ibrutinib causes CLL cell redistribution from tissue sites into the peripheral blood during the initial weeks of therapy. To better characterize the dynamics of this redistribution phenomenon, we correlated serial lymphocyte counts with volumetric changes in lymph node and spleen sizes during ibrutinib therapy. Kinetic parameters were estimated by applying a mathematical model to the data. We found that during ibrutinib therapy, 1.7% ± 1.1% of blood CLL cells and 2.7% ± 0.99% of tissue CLL cells die per day. The fraction of the tissue CLL cells that was redistributed into the blood during therapy was estimated to be 23.3% ± 17% of the total tissue disease burden. These data indicate that the reduction of tissue disease burden by ibrutinib is due more to CLL cell death and less to egress from nodal compartments. © 2014 by The American Society of Hematology.

Urea transporter proteins as targets for small-molecule diuretics.

PubMed

Esteva-Font, Cristina; Anderson, Marc O; Verkman, Alan S

2015-02-01

Conventional diuretics such as furosemide and thiazides target salt transporters in kidney tubules, but urea transporters (UTs) have emerged as alternative targets. UTs are a family of transmembrane channels expressed in a variety of mammalian tissues, in particular the kidney. UT knockout mice and humans with UT mutations exhibit reduced maximal urinary osmolality, demonstrating that UTs are necessary for the concentration of urine. Small-molecule screening has identified potent and selective inhibitors of UT-A, the UT protein expressed in renal tubule epithelial cells, and UT-B, the UT protein expressed in vasa recta endothelial cells. Data from UT knockout mice and from rodents administered UT inhibitors support the diuretic action of UT inhibition. The kidney-specific expression of UT-A1, together with high selectivity of the small-molecule inhibitors, means that off-target effects of such small-molecule drugs should be minimal. This Review summarizes the structure, expression and function of UTs, and looks at the evidence supporting the validity of UTs as targets for the development of salt-sparing diuretics with a unique mechanism of action. UT-targeted inhibitors may be useful alone or in combination with conventional diuretics for therapy of various oedemas and hyponatraemias, potentially including those refractory to treatment with current diuretics.

KSHV Targeted Therapy: An Update on Inhibitors of Viral Lytic Replication

PubMed Central

Coen, Natacha; Duraffour, Sophie; Snoeck, Robert; Andrei, Graciela

2014-01-01

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi’s sarcoma, primary effusion lymphoma and multicentric Castleman’s disease. Since the discovery of KSHV 20 years ago, there is still no standard treatment and the management of virus-associated malignancies remains toxic and incompletely efficacious. As the majority of tumor cells are latently infected with KSHV, currently marketed antivirals that target the virus lytic cycle have shown inconsistent results in clinic. Nevertheless, lytic replication plays a major role in disease progression and virus dissemination. Case reports and retrospective studies have pointed out the benefit of antiviral therapy in the treatment and prevention of KSHV-associated diseases. As a consequence, potent and selective antivirals are needed. This review focuses on the anti-KSHV activity, mode of action and current status of antiviral drugs targeting KSHV lytic cycle. Among these drugs, different subclasses of viral DNA polymerase inhibitors and compounds that do not target the viral DNA polymerase are being discussed. We also cover molecules that target cellular kinases, as well as the potential of new drug targets and animal models for antiviral testing. PMID:25421895

When Teaching Gets Tough--Professional Community Inhibitors of Teacher-Targeted Bullying and Turnover Intentions

ERIC Educational Resources Information Center

Pyhältö, Kirsi; Pietarinen, Janne; Soini, Tiina

2015-01-01

Bullying in school has become an international concern in recent decades. Yet, we know surprisingly little about inhibitors of teacher-targeted bullying. The study focused on exploring the interrelation between the teacher-working environment fit, bullying, experienced exhaustion and turnover intentions. Altogether 2310 comprehensive school…

Matrix Metalloproteases and Tissue Inhibitors of Metalloproteinases in Medial Plica and Pannus-like Tissue Contribute to Knee Osteoarthritis Progression

PubMed Central

Yang, Chih-Chang; Lin, Cheng-Yu; Wang, Hwai-Shi; Lyu, Shaw-Ruey

2013-01-01

Osteoarthritis (OA) is characterized by degradation of the cartilage matrix, leading to pathologic changes in the joints. However, the pathogenic effects of synovial tissue inflammation on OA knees are not clear. To investigate whether the inflammation caused by the medial plica is involved in the pathogenesis of osteoarthritis, we examined the expression of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), interleukin (IL)-1β, and tumor necrosis factor (TNF)-α in the medial plica and pannus-like tissue in the knees of patients with medial compartment OA who underwent either arthroscopic medial release (stage II; 15 knee joints from 15 patients) or total knee replacement (stage IV; 18 knee joints from 18 patients). MMP-2, MMP-3, MMP-9, IL-1β, and TNF-α mRNA and protein levels measured, respectively, by quantitative real-time PCR and Quantibody human MMP arrays, were highly expressed in extracts of medial plica and pannus-like tissue from stage IV knee joints. Immunohistochemical staining also demonstrated high expression of MMP-2, MMP-3, and MMP-9 in plica and pannus-like tissue of stage IV OA knees and not in normal cartilage. Some TIMP/MMP ratios decreased significantly in both medial plica and pannus-like tissue as disease progressed from stage II to stage IV. Furthermore, the migration of cells from the pannus-like tissue was enhanced by IL-1β, while plica cell migration was enhanced by TNF-α. The results suggest that medial plica and pannus-like tissue may be involved in the process of cartilage degradation in medial compartment OA of the knee. PMID:24223987

Matrix metalloproteases and tissue inhibitors of metalloproteinases in medial plica and pannus-like tissue contribute to knee osteoarthritis progression.

PubMed

Yang, Chih-Chang; Lin, Cheng-Yu; Wang, Hwai-Shi; Lyu, Shaw-Ruey

2013-01-01

Osteoarthritis (OA) is characterized by degradation of the cartilage matrix, leading to pathologic changes in the joints. However, the pathogenic effects of synovial tissue inflammation on OA knees are not clear. To investigate whether the inflammation caused by the medial plica is involved in the pathogenesis of osteoarthritis, we examined the expression of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), interleukin (IL)-1β, and tumor necrosis factor (TNF)-α in the medial plica and pannus-like tissue in the knees of patients with medial compartment OA who underwent either arthroscopic medial release (stage II; 15 knee joints from 15 patients) or total knee replacement (stage IV; 18 knee joints from 18 patients). MMP-2, MMP-3, MMP-9, IL-1β, and TNF-α mRNA and protein levels measured, respectively, by quantitative real-time PCR and Quantibody human MMP arrays, were highly expressed in extracts of medial plica and pannus-like tissue from stage IV knee joints. Immunohistochemical staining also demonstrated high expression of MMP-2, MMP-3, and MMP-9 in plica and pannus-like tissue of stage IV OA knees and not in normal cartilage. Some TIMP/MMP ratios decreased significantly in both medial plica and pannus-like tissue as disease progressed from stage II to stage IV. Furthermore, the migration of cells from the pannus-like tissue was enhanced by IL-1β, while plica cell migration was enhanced by TNF-α. The results suggest that medial plica and pannus-like tissue may be involved in the process of cartilage degradation in medial compartment OA of the knee.

Targeting Mycobacterium tuberculosis nucleoid-associated protein HU with structure-based inhibitors

NASA Astrophysics Data System (ADS)

Bhowmick, Tuhin; Ghosh, Soumitra; Dixit, Karuna; Ganesan, Varsha; Ramagopal, Udupi A.; Dey, Debayan; Sarma, Siddhartha P.; Ramakumar, Suryanarayanarao; Nagaraja, Valakunja

2014-06-01

The nucleoid-associated protein HU plays an important role in maintenance of chromosomal architecture and in global regulation of DNA transactions in bacteria. Although HU is essential for growth in Mycobacterium tuberculosis (Mtb), there have been no reported attempts to perturb HU function with small molecules. Here we report the crystal structure of the N-terminal domain of HU from Mtb. We identify a core region within the HU-DNA interface that can be targeted using stilbene derivatives. These small molecules specifically inhibit HU-DNA binding, disrupt nucleoid architecture and reduce Mtb growth. The stilbene inhibitors induce gene expression changes in Mtb that resemble those induced by HU deficiency. Our results indicate that HU is a potential target for the development of therapies against tuberculosis.

Drosophila CLOCK target gene characterization: implications for circadian tissue-specific gene expression

PubMed Central

Abruzzi, Katharine Compton; Rodriguez, Joseph; Menet, Jerome S.; Desrochers, Jennifer; Zadina, Abigail; Luo, Weifei; Tkachev, Sasha; Rosbash, Michael

2011-01-01

CLOCK (CLK) is a master transcriptional regulator of the circadian clock in Drosophila. To identify CLK direct target genes and address circadian transcriptional regulation in Drosophila, we performed chromatin immunoprecipitation (ChIP) tiling array assays (ChIP–chip) with a number of circadian proteins. CLK binding cycles on at least 800 sites with maximal binding in the early night. The CLK partner protein CYCLE (CYC) is on most of these sites. The CLK/CYC heterodimer is joined 4–6 h later by the transcriptional repressor PERIOD (PER), indicating that the majority of CLK targets are regulated similarly to core circadian genes. About 30% of target genes also show cycling RNA polymerase II (Pol II) binding. Many of these generate cycling RNAs despite not being documented in prior RNA cycling studies. This is due in part to different RNA isoforms and to fly head tissue heterogeneity. CLK has specific targets in different tissues, implying that important CLK partner proteins and/or mechanisms contribute to gene-specific and tissue-specific regulation. PMID:22085964

Targeting the disordered C-terminus of PTP1B with an allosteric inhibitor

PubMed Central

Krishnan, Navasona; Koveal, Dorothy; Miller, Daniel H.; Xue, Bin; Akshinthala, Sai Dipikaa; Kragelj, Jaka; Jensen, Malene Ringkjøbing; Gauss, Carla-Maria; Page, Rebecca; Blackledge, Martin; Muthuswamy, Senthil K.; Peti, Wolfgang; Tonks, Nicholas K.

2014-01-01

PTP1B, a validated therapeutic target for diabetes and obesity, plays a critical positive role in HER2 signaling in breast tumorigenesis. Efforts to develop therapeutic inhibitors of PTP1B have been frustrated by the chemical properties of the active site. We defined a novel mechanism of allosteric inhibition that targets the C-terminal, non-catalytic segment of PTP1B. We present the first ensemble structure of PTP1B containing this intrinsically disordered segment, within which we identified a binding site for the small molecule inhibitor, MSI-1436. We demonstrate binding to a second site close to the catalytic domain, with cooperative effects between the two sites locking PTP1B in an inactive state. MSI-1436 antagonized HER2 signaling, inhibited tumorigenesis in xenografts and abrogated metastasis in the NDL2 mouse model of breast cancer, validating inhibition of PTP1B as a therapeutic strategy in breast cancer. This new approach to inhibition of PTP1B emphasizes the potential of disordered segments of proteins as specific binding sites for therapeutic small molecules. PMID:24845231

Combined delivery of sorafenib and a MEK inhibitor using CXCR4-targeted nanoparticles reduces hepatic fibrosis and prevents tumor development

PubMed Central

Sung, Yun-Chieh; Liu, Ya-Chi; Chao, Po-Han; Chang, Chih-Chun; Jin, Pei-Ru; Lin, Ts-Ting; Lin, Ja-An; Cheng, Hui-Teng; Wang, Jane; Lai, Charles P.; Chen, Ling-Hsuan; Wu, Anthony Y.; Ho, Ting-Lun; Chiang, Tsaiyu; Gao, Dong-Yu; Duda, Dan G.; Chen, Yunching

2018-01-01

Liver damage and fibrosis are precursors of hepatocellular carcinoma (HCC). In HCC patients, sorafenib—a multikinase inhibitor drug—has been reported to exert anti-fibrotic activity. However, incomplete inhibition of RAF activity by sorafenib may also induce paradoxical activation of the mitogen-activated protein kinase (MAPK) pathway in malignant cells. The consequence of this effect in non-malignant disease (hepatic fibrosis) remains unknown. This study aimed to examine the effects of sorafenib on activated hepatic stellate cells (HSCs), and develop effective therapeutic approaches to treat liver fibrosis and prevent cancer development. Methods: We first examined the effects of sorafenib in combination with MEK inhibitors on fibrosis pathogenesis in vitro and in vivo. To improve the bioavailability and absorption by activated HSCs, we developed CXCR4-targeted nanoparticles (NPs) to co-deliver sorafenib and a MEK inhibitor to mice with liver damage. Results: We found that sorafenib induced MAPK activation in HSCs, and promoted their myofibroblast differentiation. Combining sorafenib with a MEK inhibitor suppressed both paradoxical MAPK activation and HSC activation in vitro, and alleviated liver fibrosis in a CCl4-induced murine model of liver damage. Furthermore, treatment with sorafenib/MEK inhibitor-loaded CXCR4-targeted NPs significantly suppressed hepatic fibrosis progression and further prevented fibrosis-associated HCC development and liver metastasis. Conclusions: Our results show that combined delivery of sorafenib and a MEK inhibitor via CXCR4-targeted NPs can prevent activation of ERK in activated HSCs and has anti-fibrotic effects in the CCl4-induced murine model. Targeting HSCs represents a promising strategy to prevent the development and progression of fibrosis-associated HCC. PMID:29463989

Histone-Targeted Nucleic Acid Delivery for Tissue Regenerative Applications

NASA Astrophysics Data System (ADS)

Munsell, Erik V.

Nucleic acid delivery has garnered significant attention as an innovative therapeutic approach for treating a wide variety of diseases. However, the design of non-viral delivery systems that negotiate efficient intracellular trafficking and nuclear entry represents a significant challenge. Overcoming these hurdles requires a combination of well-controlled materials approaches with techniques to understand and direct cellular delivery. Recent investigations have highlighted the roles histone tail sequences play in directing nuclear delivery and retention, as well as activating DNA transcription. We established the ability to recapitulate these natural histone tail activities within non-viral gene nanocarriers, driving gene transfer/expression by enabling effective navigation to the nucleus via retrograde vesicular trafficking. A unique finding of this histone-targeted approach was that nanocarriers gained enhanced access to the nucleus during mitosis. The work described in this dissertation builds off of these fundamental insights to facilitate the translation of this histone-targeted delivery approach toward regenerative medicine applications. During native tissue repair, actively proliferating mesenchymal stem cells (MSCs) respond to a complex series of growth factor signals that direct their differentiation. Accordingly, the investigations in this work focused on utilizing the histone-targeted nanocarriers to enhance osteogenic growth factor gene transfer in dividing MSCs leading to augmented MSC chondrogenic differentiation, an essential first step in skeletal tissue repair. Concurrently, additional studies focused on optimizing the histone-targeted nanocarrier design strategy to enable improved plasmid DNA (pDNA) binding stability and tunable harnessing of native cellular processing pathways for enhanced gene transfer. Overall, the work presented herein demonstrated substantial increases in growth factor expression following histone-targeted gene transfer. This

Localized increase of tissue oxygen tension by magnetic targeted drug delivery

NASA Astrophysics Data System (ADS)

Liong, Celine; Ortiz, Daniel; Ao-ieong, Eilleen; Navati, Mahantesh S.; Friedman, Joel M.; Cabrales, Pedro

2014-07-01

Hypoxia is the major hindrance to successful radiation therapy of tumors. Attempts to increase the oxygen (O2) tension (PO2) of tissue by delivering more O2 have been clinically disappointing, largely due to the way O2 is transported and released by the hemoglobin (Hb) within the red blood cells (RBCs). Systemic manipulation of O2 transport increases vascular resistance due to metabolic autoregulation of blood flow to prevent over oxygenation. This study investigates a new technology to increase O2 delivery to a target tissue by decreasing the Hb-O2 affinity of the blood circulating within the targeted tissue. As the Hb-O2 affinity decreases, the tissue PO2 to satisfy tissue O2 metabolic needs increases without increasing O2 delivery or extraction. Paramagnetic nanoparticles (PMNPs), synthetized using gadolinium oxide, were coated with the cell permeable Hb allosteric effector L35 (3,5-trichlorophenylureido-phenoxy-methylpropionic acid). L35 decreases Hb affinity for O2 and favors the release of O2. The L35-coated PMNPs (L35-PMNPs) were intravenously infused (10 mg kg-1) to hamsters instrumented with the dorsal window chamber model. A magnetic field of 3 mT was applied to localize the effects of the L35-PMNPs to the window chamber. Systemic O2 transport characteristics and microvascular tissue oxygenation were measured after administration of L35-PMNPs with and without magnetic field. The tissue PO2 in untreated control animals was 25.2 mmHg. L35-PMNPs without magnetic field decreased tissue PO2 to 23.4 mmHg, increased blood pressure, and reduced blood flow, largely due to systemic modification of Hb-O2 affinity. L35-PMNPs with magnetic field increased tissue PO2 to 27.9 mmHg, without systemic or microhemodynamic changes. These results indicate that localized modification of Hb-O2 affinity can increase PO2 of target tissue without affecting systemic O2 delivery or triggering O2 autoregulation mechanisms. This technology can be used to treat local hypoxia and to

Development of a Photo-Cross-Linkable Diaminoquinazoline Inhibitor for Target Identification in Plasmodium falciparum.

PubMed

Lubin, Alexandra S; Rueda-Zubiaurre, Ainoa; Matthews, Holly; Baumann, Hella; Fisher, Fabio R; Morales-Sanfrutos, Julia; Hadavizadeh, Kate S; Nardella, Flore; Tate, Edward W; Baum, Jake; Scherf, Artur; Fuchter, Matthew J

2018-04-13

Diaminoquinazolines represent a privileged scaffold for antimalarial discovery, including use as putative Plasmodium histone lysine methyltransferase inhibitors. Despite this, robust evidence for their molecular targets is lacking. Here we report the design and development of a small-molecule photo-cross-linkable probe to investigate the targets of our diaminoquinazoline series. We demonstrate the effectiveness of our designed probe for photoaffinity labeling of Plasmodium lysates and identify similarities between the target profiles of the probe and the representative diaminoquinazoline BIX-01294. Initial pull-down proteomics experiments identified 104 proteins from different classes, many of which are essential, highlighting the suitability of the developed probe as a valuable tool for target identification in Plasmodium falciparum.

Targeting the Myofibroblast Genetic Switch: Inhibitors of Myocardin-Related Transcription Factor/Serum Response Factor–Regulated Gene Transcription Prevent Fibrosis in a Murine Model of Skin Injury

PubMed Central

Haak, Andrew J.; Tsou, Pei-Suen; Amin, Mohammad A.; Ruth, Jeffrey H.; Campbell, Phillip; Fox, David A.; Khanna, Dinesh; Larsen, Scott D.

2014-01-01

Systemic sclerosis (SSc), or scleroderma, similar to many fibrotic disorders, lacks effective therapies. Current trials focus on anti-inflammatory drugs or targeted approaches aimed at one of the many receptor mechanisms initiating fibrosis. In light of evidence that a myocardin-related transcription factor (MRTF)–and serum response factor (SRF)–regulated gene transcriptional program induced by Rho GTPases is essential for myofibroblast activation, we explored the hypothesis that inhibitors of this pathway may represent novel antifibrotics. MRTF/SRF-regulated genes show spontaneously increased expression in primary dermal fibroblasts from patients with diffuse cutaneous SSc. A novel small-molecule inhibitor of MRTF/SRF-regulated transcription (CCG-203971) inhibits expression of connective tissue growth factor (CTGF), α-smooth muscle actin (α-SMA), and collagen 1 (COL1A2) in both SSc fibroblasts and in lysophosphatidic acid (LPA)–and transforming growth factor β (TGFβ)–stimulated fibroblasts. In vivo treatment with CCG-203971 also prevented bleomycin-induced skin thickening and collagen deposition. Thus, targeting the MRTF/SRF gene transcription pathway could provide an efficacious new approach to therapy for SSc and other fibrotic disorders. PMID:24706986

Inhibition of Axl improves the targeted therapy against ALK-mutated neuroblastoma

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

Xu, Fei; Li, Hongling; Sun, Yong, E-mail: sunfanqi2010@163.com

2014-11-28

Highlights: • First reported Axl is co-expressed with ALK in neuroblastoma tissues and cell lines. • Axl activation promotes cell growth and impairs the efficiency of ALK inhibitor. • Further found silence of Axl leads to increased sensitivity to ALK inhibitors. • Axl inhibitor promotes the efficiency of targeted therapy in vitro and in vivo. • Axl activation should be considered in the clinical application of ALK inhibitors. - Abstract: Neuroblastoma (NB) patients harboring mutated ALK can be expected to potentially benefit from targeted therapy based on ALK tyrosine kinase inhibitor (TKI), such as crizotinib and ceritinib. However, the effectmore » of the treatment varies with different individuals, although with the same genic changes. Axl receptor tyrosine kinase is expressed in a variety of human cancers, but little data are reported in NB, particularly in which carrying mutated ALK. In this study, we focus on the roles of Axl in ALK-mutated NB for investigating rational therapeutic strategy. We found that Axl is expressed in ALK-positive NB tissues and cell lines, and could be effectively activated by its ligand GAS6. Ligand-dependent Axl activation obviously rescued crizotinib-mediated suppression of cell proliferation in ALK-mutated NB cells. Genetic inhibition of Axl with specific small interfering RNA markedly increased the sensitivity of cells to ALK-TKIs. Furthermore, a small-molecule inhibitor of Axl significantly enhanced ALK-targeted therapy, as an increased frequency of apoptosis was observed in NB cells co-expressing ALK and Axl. Taken together, our results demonstrated that activation of Axl could lead to insensitivity to ALK inhibitors, and dual inhibition of ALK and Axl might be a potential therapeutic strategy against ALK-mutated NB.« less

Relative binding affinity of carboxylate-, phosphonate-, and bisphosphonate-functionalized gold nanoparticles targeted to damaged bone tissue

NASA Astrophysics Data System (ADS)

Ross, Ryan D.; Cole, Lisa E.; Roeder, Ryan K.

2012-10-01

Functionalized Au NPs have received considerable recent interest for targeting and labeling cells and tissues. Damaged bone tissue can be targeted by functionalizing Au NPs with molecules exhibiting affinity for calcium. Therefore, the relative binding affinity of Au NPs surface functionalized with either carboxylate ( l-glutamic acid), phosphonate (2-aminoethylphosphonic acid), or bisphosphonate (alendronate) was investigated for targeted labeling of damaged bone tissue in vitro. Targeted labeling of damaged bone tissue was qualitatively verified by visual observation and backscattered electron microscopy, and quantitatively measured by the surface density of Au NPs using field-emission scanning electron microscopy. The surface density of functionalized Au NPs was significantly greater within damaged tissue compared to undamaged tissue for each functional group. Bisphosphonate-functionalized Au NPs exhibited a greater surface density labeling damaged tissue compared to glutamic acid- and phosphonic acid-functionalized Au NPs, which was consistent with the results of previous work comparing the binding affinity of the same functionalized Au NPs to synthetic hydroxyapatite crystals. Targeted labeling was enabled not only by the functional groups but also by the colloidal stability in solution. Functionalized Au NPs were stabilized by the presence of the functional groups, and were shown to remain well dispersed in ionic (phosphate buffered saline) and serum (fetal bovine serum) solutions for up to 1 week. Therefore, the results of this study suggest that bisphosphonate-functionalized Au NPs have potential for targeted delivery to damaged bone tissue in vitro and provide motivation for in vivo investigation.

Reducing the background fluorescence in mice receiving fluorophore/inhibitor DNA duplexes.

PubMed

Liang, Minmin; Liu, Xinrong; Liu, Guozheng; Dou, Shuping; Cheng, Dengfeng; Liu, Yuxia; Rusckowski, Mary; Hnatowich, Donald J

2011-02-07

In principle, a DNA duplex consisting of an antisense fluorophore-conjugated major strand hybridized to a shorter complementary inhibitor-conjugated minor strand should provide fluorescence only in the tumor after intravenous administration if designed to remain intact except in the presence in tumor of its mRNA target. While we have obtained impressive tumor images in mice using this approach, there remains some background fluorescence. In this study, tissue homogenates of selected mouse organs were incubated with a test duplex and the kinetics of duplex dissociation in normal tissues were measured. In this manner we were able to identify the liver as the likely major source responsible for the duplex dissociation providing this fluorescence background. Thereafter liver homogenates were used to screen a series of duplex candidates with variable-length minor strands, and dissociation was measured by gel electrophoresis. The selected fluorophore/inhibitor duplex with improved stability displayed an insignificant (P > 0.05) background fluorescence after administration to SKH-1 normal mice and apparently without affecting target mRNA binding in vitro in cell culture or in vivo in tumor bearing mice.

Targeted Fluoro Positioning for the Discovery of a Potent and Highly Selective Matrix Metalloproteinase Inhibitor.

PubMed

Fischer, Thomas; Riedl, Rainer

2017-04-01

Invited for this month's cover picture is the group of Professor Rainer Riedl from the Institute of Chemistry and Biotechnology at the Zurich University of Applied Sciences (ZHAW), Switzerland. The cover picture depicts the structure-based design of a drug-like small molecule inhibitor of matrix metalloproteinase-13 (MMP-13) with a combined dual binding motif. The targeted introduction of a single fluoro atom was of vital importance for the optimization of the inhibitor. For more details, read the full text of the Communication at 10.1002/open.201600158.

Structural and mechanistic basis of differentiated inhibitors of the acute pancreatitis target kynurenine-3-monooxygenase

NASA Astrophysics Data System (ADS)

Hutchinson, Jonathan P.; Rowland, Paul; Taylor, Mark R. D.; Christodoulou, Erica M.; Haslam, Carl; Hobbs, Clare I.; Holmes, Duncan S.; Homes, Paul; Liddle, John; Mole, Damian J.; Uings, Iain; Walker, Ann L.; Webster, Scott P.; Mowat, Christopher G.; Chung, Chun-Wa

2017-06-01

Kynurenine-3-monooxygenase (KMO) is a key FAD-dependent enzyme of tryptophan metabolism. In animal models, KMO inhibition has shown benefit in neurodegenerative diseases such as Huntington's and Alzheimer's. Most recently it has been identified as a target for acute pancreatitis multiple organ dysfunction syndrome (AP-MODS); a devastating inflammatory condition with a mortality rate in excess of 20%. Here we report and dissect the molecular mechanism of action of three classes of KMO inhibitors with differentiated binding modes and kinetics. Two novel inhibitor classes trap the catalytic flavin in a previously unobserved tilting conformation. This correlates with picomolar affinities, increased residence times and an absence of the peroxide production seen with previous substrate site inhibitors. These structural and mechanistic insights culminated in GSK065(C1) and GSK366(C2), molecules suitable for preclinical evaluation. Moreover, revising the repertoire of flavin dynamics in this enzyme class offers exciting new opportunities for inhibitor design.

Structural and mechanistic basis of differentiated inhibitors of the acute pancreatitis target kynurenine-3-monooxygenase.

PubMed

Hutchinson, Jonathan P; Rowland, Paul; Taylor, Mark R D; Christodoulou, Erica M; Haslam, Carl; Hobbs, Clare I; Holmes, Duncan S; Homes, Paul; Liddle, John; Mole, Damian J; Uings, Iain; Walker, Ann L; Webster, Scott P; Mowat, Christopher G; Chung, Chun-Wa

2017-06-12

Kynurenine-3-monooxygenase (KMO) is a key FAD-dependent enzyme of tryptophan metabolism. In animal models, KMO inhibition has shown benefit in neurodegenerative diseases such as Huntington's and Alzheimer's. Most recently it has been identified as a target for acute pancreatitis multiple organ dysfunction syndrome (AP-MODS); a devastating inflammatory condition with a mortality rate in excess of 20%. Here we report and dissect the molecular mechanism of action of three classes of KMO inhibitors with differentiated binding modes and kinetics. Two novel inhibitor classes trap the catalytic flavin in a previously unobserved tilting conformation. This correlates with picomolar affinities, increased residence times and an absence of the peroxide production seen with previous substrate site inhibitors. These structural and mechanistic insights culminated in GSK065(C1) and GSK366(C2), molecules suitable for preclinical evaluation. Moreover, revising the repertoire of flavin dynamics in this enzyme class offers exciting new opportunities for inhibitor design.

Structural and mechanistic basis of differentiated inhibitors of the acute pancreatitis target kynurenine-3-monooxygenase

PubMed Central

Hutchinson, Jonathan P.; Rowland, Paul; Taylor, Mark R. D.; Christodoulou, Erica M.; Haslam, Carl; Hobbs, Clare I.; Holmes, Duncan S.; Homes, Paul; Liddle, John; Mole, Damian J.; Uings, Iain; Walker, Ann L.; Webster, Scott P.; Mowat, Christopher G.; Chung, Chun-wa

2017-01-01

Kynurenine-3-monooxygenase (KMO) is a key FAD-dependent enzyme of tryptophan metabolism. In animal models, KMO inhibition has shown benefit in neurodegenerative diseases such as Huntington's and Alzheimer's. Most recently it has been identified as a target for acute pancreatitis multiple organ dysfunction syndrome (AP-MODS); a devastating inflammatory condition with a mortality rate in excess of 20%. Here we report and dissect the molecular mechanism of action of three classes of KMO inhibitors with differentiated binding modes and kinetics. Two novel inhibitor classes trap the catalytic flavin in a previously unobserved tilting conformation. This correlates with picomolar affinities, increased residence times and an absence of the peroxide production seen with previous substrate site inhibitors. These structural and mechanistic insights culminated in GSK065(C1) and GSK366(C2), molecules suitable for preclinical evaluation. Moreover, revising the repertoire of flavin dynamics in this enzyme class offers exciting new opportunities for inhibitor design. PMID:28604669

Cyclin Dependent Kinase Inhibitors as Targets in Ovarian Cancer

DTIC Science & Technology

2005-10-01

STATEMENT Approved for Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The objective of this proposal is to develop gene ...have identified key genes that may be effective targets in ovarian cancer therapy. The first three projects seek to identify alterations in these genes ...that allow for high expression of our key gene (s) in ovarian cancer cells but minimal expression in normal tissues. 15. SUBJECT TERMS Cell cycle control

TargetMiner: microRNA target prediction with systematic identification of tissue-specific negative examples.

PubMed

Bandyopadhyay, Sanghamitra; Mitra, Ramkrishna

2009-10-15

Prediction of microRNA (miRNA) target mRNAs using machine learning approaches is an important area of research. However, most of the methods suffer from either high false positive or false negative rates. One reason for this is the marked deficiency of negative examples or miRNA non-target pairs. Systematic identification of non-target mRNAs is still not addressed properly, and therefore, current machine learning approaches are compelled to rely on artificially generated negative examples for training. In this article, we have identified approximately 300 tissue-specific negative examples using a novel approach that involves expression profiling of both miRNAs and mRNAs, miRNA-mRNA structural interactions and seed-site conservation. The newly generated negative examples are validated with pSILAC dataset, which elucidate the fact that the identified non-targets are indeed non-targets.These high-throughput tissue-specific negative examples and a set of experimentally verified positive examples are then used to build a system called TargetMiner, a support vector machine (SVM)-based classifier. In addition to assessing the prediction accuracy on cross-validation experiments, TargetMiner has been validated with a completely independent experimental test dataset. Our method outperforms 10 existing target prediction algorithms and provides a good balance between sensitivity and specificity that is not reflected in the existing methods. We achieve a significantly higher sensitivity and specificity of 69% and 67.8% based on a pool of 90 feature set and 76.5% and 66.1% using a set of 30 selected feature set on the completely independent test dataset. In order to establish the effectiveness of the systematically generated negative examples, the SVM is trained using a different set of negative data generated using the method in Yousef et al. A significantly higher false positive rate (70.6%) is observed when tested on the independent set, while all other factors are kept the

Targeted metabolomic profiling in rat tissues reveals sex differences.

PubMed

Ruoppolo, Margherita; Caterino, Marianna; Albano, Lucia; Pecce, Rita; Di Girolamo, Maria Grazia; Crisci, Daniela; Costanzo, Michele; Milella, Luigi; Franconi, Flavia; Campesi, Ilaria

2018-03-16

Sex differences affect several diseases and are organ-and parameter-specific. In humans and animals, sex differences also influence the metabolism and homeostasis of amino acids and fatty acids, which are linked to the onset of diseases. Thus, the use of targeted metabolite profiles in tissues represents a powerful approach to examine the intermediary metabolism and evidence for any sex differences. To clarify the sex-specific activities of liver, heart and kidney tissues, we used targeted metabolomics, linear discriminant analysis (LDA), principal component analysis (PCA), cluster analysis and linear correlation models to evaluate sex and organ-specific differences in amino acids, free carnitine and acylcarnitine levels in male and female Sprague-Dawley rats. Several intra-sex differences affect tissues, indicating that metabolite profiles in rat hearts, livers and kidneys are organ-dependent. Amino acids and carnitine levels in rat hearts, livers and kidneys are affected by sex: male and female hearts show the greatest sexual dimorphism, both qualitatively and quantitatively. Finally, multivariate analysis confirmed the influence of sex on the metabolomics profiling. Our data demonstrate that the metabolomics approach together with a multivariate approach can capture the dynamics of physiological and pathological states, which are essential for explaining the basis of the sex differences observed in physiological and pathological conditions.

Novel multi-targeted ErbB family inhibitor afatinib blocks EGF-induced signaling and induces apoptosis in neuroblastoma.

PubMed

Mao, Xinfang; Chen, Zhenghu; Zhao, Yanling; Yu, Yang; Guan, Shan; Woodfield, Sarah E; Vasudevan, Sanjeev A; Tao, Ling; Pang, Jonathan C; Lu, Jiaxiong; Zhang, Huiyuan; Zhang, Fuchun; Yang, Jianhua

2017-01-03

Neuroblastoma is the most common extracranial solid tumor in children. The ErbB family of proteins is a group of receptor tyrosine kinases that promote the progression of various malignant cancers including neuroblastoma. Thus, targeting them with small molecule inhibitors is a promising strategy for neuroblastoma therapy. In this study, we investigated the anti-tumor effect of afatinib, an irreversible inhibitor of members of the ErbB family, on neuroblastoma. We found that afatinib suppressed the proliferation and colony formation ability of neuroblastoma cell lines in a dose-dependent manner. Afatinib also induced apoptosis and blocked EGF-induced activation of PI3K/AKT/mTOR signaling in all neuroblastoma cell lines tested. In addition, afatinib enhanced doxorubicin-induced cytotoxicity in neuroblastoma cells, including the chemoresistant LA-N-6 cell line. Finally, afatinib exhibited antitumor efficacy in vivo by inducing apoptosis in an orthotopic xenograft neuroblastoma mouse model. Taken together, these results show that afatinib inhibits neuroblastoma growth both in vitro and in vivo by suppressing EGFR-mediated PI3K/AKT/mTOR signaling. Our study supports the idea that EGFR is a potential therapeutic target in neuroblastoma. And targeting ErbB family protein kinases with small molecule inhibitors like afatinib alone or in combination with doxorubicin is a viable option for treating neuroblastoma.

Influence of Expression Plasmid of Connective Tissue Growth Factor and Tissue Inhibitor of Metalloproteinase-1 shRNA on Hepatic Precancerous Fibrosis in Rats.

PubMed

Zhang, Qun; Shu, Fu-Li; Jiang, Yu-Feng; Huang, Xin-En

2015-01-01

In this study, influence caused by expression plasmids of connective tissue growth factor (CTGF) and tissue inhibitor of metalloproteinase-1 (TIMP-1) short hairpin RNA (shRNA) on mRNA expression of CTGF,TIMP-1,procol-α1 and PCIII in hepatic tissue with hepatic fibrosis, a precancerous condition, in rats is analyzed. To screen and construct shRNA expression plasimid which effectively interferes RNA targets of CTGF and TIMP-1 in rats. 50 cleaning Wistar male rats are allocated randomly at 5 different groups after precancerous fibrosis models and then injection of shRNA expression plasimids. Plasmid psiRNA-GFP-Com (CTGF and TIMP-1 included), psiRNA-GFP-CTGF, psiRNA-GFP-TIMP-1 and psiRNA- DUO-GFPzeo of blank plasmid are injected at group A, B, C and D, respectively, and as model control group that none plasimid is injected at group E. In 2 weeks after last injection, to hepatic tissue at different groups, protein expression of CTGF, TIMP-1, procol-α1and PC III is tested by immunohistochemical method and,mRNA expression of CTGF,TIMP-1,procol-α1 and PCIII is measured by real-time PCR. One-way ANOVA is used to comparison between-groups. Compared with model group, there is no obvious difference of mRNA expression among CTGF,TIMP-1,procol-α1,PC III and of protein expression among CTGF, TIMP-1, procol-α1, PC III in hepatic tissue at group injected with blank plasmid. Expression quantity of mRNA of CTGF, TIMP-1, procol-α1 and PCIII at group A, B and C decreases, protein expression of CTGF, TIMP-1, procol-α1, PC III in hepatic tissue is lower, where the inhibition of combination RNA interference group (group A) on procol-α1 mRNA transcription and procol-α1 protein expression is superior to that of single interference group (group B and C) (P<0.01 or P<0.05). RNA interference on CTGF and/or TIMP-1 is obviously a inhibiting factor for mRNA and protein expression of CTGF, TIMP-1, procol-α1 and PCIII. Combination RNA interference on genes of CTGF and TIMP-1 is superior

Preclinical evaluation of transcriptional targeting strategies for carcinoma of the breast in a tissue slice model system

PubMed Central

Stoff-Khalili, Mariam A; Stoff, Alexander; Rivera, Angel A; Banerjee, Nilam S; Everts, Maaike; Young, Scott; Siegal, Gene P; Richter, Dirk F; Wang, Minghui; Dall, Peter; Mathis, J Michael; Zhu, Zeng B; Curiel, David T

2005-01-01

Introduction In view of the limited success of available treatment modalities for metastatic breast cancer, alternative and complementary strategies need to be developed. Adenoviral vector mediated strategies for breast cancer gene therapy and virotherapy are a promising novel therapeutic platform for the treatment of breast cancer. However, the promiscuous tropism of adenoviruses (Ads) is a major concern. Employing tissue specific promoters (TSPs) to restrict transgene expression or viral replication is an effective way to increase specificity towards tumor tissues and to reduce adverse effects in non-target tissues such as the liver. In this regard, candidate breast cancer TSPs include promoters of the genes for the epithelial glycoprotein 2 (EGP-2), cyclooxygenase-2 (Cox-2), α-chemokine SDF-1 receptor (stromal-cell-derived factor, CXCR4), secretory leukoprotease inhibitor (SLPI) and survivin. Methods We employed E1-deleted Ads that express the reporter gene luciferase under the control of the promoters of interest. We evaluated this class of vectors in various established breast cancer cell lines, primary breast cancer cells and finally in the most stringent preclinical available substrate system, constituted by precision cut tissue slices of human breast cancer and liver. Results Overall, the CXCR4 promoter exhibited the highest luciferase activity in breast cancer cell lines, primary breast cancer cells and breast cancer tissue slices. Importantly, the CXCR4 promoter displayed a very low activity in human primary fibroblasts and human liver tissue slices. Interestingly, gene expression profiles correlated with the promoter activities both in breast cancer cell lines and primary breast cancer cells. Conclusion These data suggest that the CXCR4 promoter has an ideal 'breast cancer-on/liver-off' profile, and could, therefore, be a powerful tool in Ad vector based gene therapy or virotherapy of the carcinoma of the breast. PMID:16457694

Discovery of Fungal Denitrification Inhibitors by Targeting Copper Nitrite Reductase from Fusarium oxysporum.

PubMed

Matsuoka, Masaki; Kumar, Ashutosh; Muddassar, Muhammad; Matsuyama, Akihisa; Yoshida, Minoru; Zhang, Kam Y J

2017-02-27

The efficient application of nitrogenous fertilizers is urgently required, as their excessive and inefficient use is causing substantial economic loss and environmental pollution. A significant amount of applied nitrogen in agricultural soils is lost as nitrous oxide (N 2 O) in the environment due to the microbial denitrification process. The widely distributed fungus Fusarium oxysporum is a major denitrifier in agricultural soils and its denitrification activity could be targeted to reduce nitrogen loss in the form of N 2 O from agricultural soils. Here, we report the discovery of first small molecule inhibitors of copper nitrite reductase (NirK) from F. oxysporum, which is a key enzyme in the fungal denitrification process. The inhibitors were discovered by a hierarchical in silico screening approach consisting of pharmacophore modeling and molecular docking. In vitro evaluation of F. oxysporum NirK activity revealed several pyrimidone and triazinone based compounds with potency in the low micromolar range. Some of these compounds suppressed the fungal denitrification in vivo as well. The compounds reported here could be used as starting points for the development of nitrogenous fertilizer supplements and coatings as a means to prevent nitrogen loss by targeting fungal denitrification.

Computational-experimental approach to drug-target interaction mapping: A case study on kinase inhibitors

PubMed Central

Ravikumar, Balaguru; Parri, Elina; Timonen, Sanna; Airola, Antti; Wennerberg, Krister

2017-01-01

Due to relatively high costs and labor required for experimental profiling of the full target space of chemical compounds, various machine learning models have been proposed as cost-effective means to advance this process in terms of predicting the most potent compound-target interactions for subsequent verification. However, most of the model predictions lack direct experimental validation in the laboratory, making their practical benefits for drug discovery or repurposing applications largely unknown. Here, we therefore introduce and carefully test a systematic computational-experimental framework for the prediction and pre-clinical verification of drug-target interactions using a well-established kernel-based regression algorithm as the prediction model. To evaluate its performance, we first predicted unmeasured binding affinities in a large-scale kinase inhibitor profiling study, and then experimentally tested 100 compound-kinase pairs. The relatively high correlation of 0.77 (p < 0.0001) between the predicted and measured bioactivities supports the potential of the model for filling the experimental gaps in existing compound-target interaction maps. Further, we subjected the model to a more challenging task of predicting target interactions for such a new candidate drug compound that lacks prior binding profile information. As a specific case study, we used tivozanib, an investigational VEGF receptor inhibitor with currently unknown off-target profile. Among 7 kinases with high predicted affinity, we experimentally validated 4 new off-targets of tivozanib, namely the Src-family kinases FRK and FYN A, the non-receptor tyrosine kinase ABL1, and the serine/threonine kinase SLK. Our sub-sequent experimental validation protocol effectively avoids any possible information leakage between the training and validation data, and therefore enables rigorous model validation for practical applications. These results demonstrate that the kernel-based modeling approach

Gene Delivery to Adipose Tissue Using Transcriptionally Targeted rAAV8 Vectors

PubMed Central

Uhrig-Schmidt, Silke; Geiger, Matthias; Luippold, Gerd; Birk, Gerald; Mennerich, Detlev; Neubauer, Heike; Grimm, Dirk; Wolfrum, Christian; Kreuz, Sebastian

2014-01-01

In recent years, the increasing prevalence of obesity and obesity-related co-morbidities fostered intensive research in the field of adipose tissue biology. To further unravel molecular mechanisms of adipose tissue function, genetic tools enabling functional studies in vitro and in vivo are essential. While the use of transgenic animals is well established, attempts using viral and non-viral vectors to genetically modify adipocytes in vivo are rare. Therefore, we here characterized recombinant Adeno-associated virus (rAAV) vectors regarding their potency as gene transfer vehicles for adipose tissue. Our results demonstrate that a single dose of systemically applied rAAV8-CMV-eGFP can give rise to remarkable transgene expression in murine adipose tissues. Upon transcriptional targeting of the rAAV8 vector to adipocytes using a 2.2 kb fragment of the murine adiponectin (mAP2.2) promoter, eGFP expression was significantly decreased in off-target tissues while efficient transduction was maintained in subcutaneous and visceral fat depots. Moreover, rAAV8-mAP2.2-mediated expression of perilipin A – a lipid-droplet-associated protein – resulted in significant changes in metabolic parameters only three weeks post vector administration. Taken together, our findings indicate that rAAV vector technology is applicable as a flexible tool to genetically modify adipocytes for functional proof-of-concept studies and the assessment of putative therapeutic targets in vivo. PMID:25551639

Endocrine disruptors and other inhibitors of 11β-hydroxysteroid dehydrogenase 1 and 2: Tissue-specific consequences of enzyme inhibition.

PubMed

Vitku, Jana; Starka, Luboslav; Bicikova, Marie; Hill, Martin; Heracek, Jiri; Sosvorova, Lucie; Hampl, Richard

2016-01-01

Numerous chemicals in the environment have the ability to interact with the endocrine system. These compounds are called endocrine disruptors (EDs). Exposure to EDs represents one of the hypotheses for decreasing fertility, the increased risk of numerous cancers and obesity, metabolic syndrome and type 2 diabetes. There are various mechanisms of ED action, one of which is their interference in the action of 11β-hydroxysteroid dehydrogenase (11βHSD) that maintains a balance between active and inactive glucocorticoids on the intracellular level. This enzyme has two isoforms and is expressed in various tissues. Inhibition of 11βHSD in various tissues can have different consequences. In the case of EDs, the results of exposure are mainly adverse; on the other hand pharmaceutically developed inhibitors of 11βHSD type 1 are evaluated as an option for treating metabolic syndrome, as well as related diseases and depressive disorders. This review focuses on the effects of 11βHSD inhibitors in the testis, colon, adipose tissue, kidney, brain and placenta. Copyright © 2014 Elsevier Ltd. All rights reserved.

EphB4 as a therapeutic target in mesothelioma

PubMed Central

2013-01-01

Background Malignant pleural mesothelioma (MPM) often develops decades following exposure to asbestos. Current best therapy produces a response in only half of patients, and the median survival with this therapy remains under a year. A search for novel targets and therapeutics is underway, and recently identified targets include VEGF, Notch, and EphB4-Ephrin-B2. Each of these targets has dual activity, promoting tumor cell growth as well as tumor angiogenesis. Methods We investigated EphB4 expression in 39 human mesothelioma tissues by immunohistochemistry. Xenograft tumors established with human mesothelioma cells were treated with an EphB4 inhibitor (monomeric soluble EphB4 fused to human serum albumin, or sEphB4-HSA). The combinatorial effect of sEphB4-HSA and biologic agent was also studied. Results EphB4 was overexpressed in 72% of mesothelioma tissues evaluated, with 85% of epithelioid and 38% of sarcomatoid subtypes demonstrating overexpression. The EphB4 inhibitor sEphB4-HSA was highly active as a single agent to inhibit tumor growth, accompanied by tumor cell apoptosis and inhibition of PI3K and Src signaling. Combination of sEphB4-HSA and the anti-VEGF antibody (Bevacizumab) was superior to each agent alone and led to complete tumor regression. Conclusion EphB4 is a potential therapeutic target in mesothelioma. Clinical investigation of sEphB4-HSA as a single agent and in combination with VEGF inhibitors is warranted. PMID:23721559

[Recent Advances and Prospect of Advanced Non-small Cell Lung Cancer Targeted 
Therapy: Focus on Small Molecular Tyrosine Kinase Inhibitors].

PubMed

Zhang, Guowei; Wang, Huijuan; Ma, Zhiyong

2017-04-20

At present the treatment of advanced non-small cell lung cancer enters a targeted era and develops rapidly. New drugs appear constantly. Small molecular tyrosine kinase inhibitors have occupied the biggest piece of the territory, which commonly have a clear biomarker as predictor, and show remarkable effect in specific molecular classification of patients. The epidermal growth factor tyrosine kinase inhibitors such as gefitinib, erlotinib, icotinib and anaplastic lymphoma kinase tyrosine kinase inhibitors crizotinib have brought a milestone advance. In recent years new generations of tyrosine kinase inhibitors have achieved a great success in patients with acquired resistance to the above two kinds of drugs. At the same time new therapeutic targets are constantly emerging. So in this paper, we reviewed and summarized the important drugs and clinical trails on this topic, and made a prospect of the future development.

A novel angiogenesis inhibitor impairs lovo cell survival via targeting against human VEGFR and its signaling pathway of phosphorylation.

PubMed

Zhang, Y M; Dai, B L; Zheng, L; Zhan, Y Z; Zhang, J; Smith, W W; Wang, X L; Chen, Y N; He, L C

2012-10-11

Colorectal cancer represents the fourth commonest malignancy, and constitutes a major cause of significant morbidity and mortality among other diseases. However, the chemical therapy is still under development. Angiogenesis plays an important role in colon cancer development. We developed HMQ18-22 (a novel analog of taspine) with the aim to target angiogenesis. We found that HMQ18-22 significantly reduced angiogenesis of chicken chorioallantoic membrane (CAM) and mouse colon tissue, and inhibited cell migration and tube formation as well. Then, we verified the interaction between HMQ18-22 and VEGFR2 by AlphaScreen P-VEGFR assay, screened the targets on angiogenesis by VEGF Phospho Antibody Array, validated the target by western blot and RNAi in lovo cells. We found HMQ18-22 could decrease phosphorylation of VEGFR2(Tyr(1214)), VEGFR1(Tyr(1333)), Akt(Tyr(326)), protein kinase Cα (PKCα) (Tyr(657)) and phospholipase-Cγ-1 (PLCγ-1) (Tyr(771)). Most importantly, HMQ18-22 inhibited proliferation of lovo cell and tumor growth in a human colon tumor xenografted model of athymic mice. Compared with normal lovo cells proliferation, the inhibition on proliferation of knockdown cells (VEGFR2, VEGFR1, Akt, PKCα and PLCγ-1) by HMQ18-22 decreased. These results suggested that HMQ18-22 is a novel angiogenesis inhibitor and can be a useful therapeutic candidate for colon cancer intervention.

X-ray crystal structure of plasmin with tranexamic acid-derived active site inhibitors.

PubMed

Law, Ruby H P; Wu, Guojie; Leung, Eleanor W W; Hidaka, Koushi; Quek, Adam J; Caradoc-Davies, Tom T; Jeevarajah, Devadharshini; Conroy, Paul J; Kirby, Nigel M; Norton, Raymond S; Tsuda, Yuko; Whisstock, James C

2017-05-09

The zymogen protease plasminogen and its active form plasmin perform key roles in blood clot dissolution, tissue remodeling, cell migration, and bacterial pathogenesis. Dysregulation of the plasminogen/plasmin system results in life-threatening hemorrhagic disorders or thrombotic vascular occlusion. Accordingly, inhibitors of this system are clinically important. Currently, tranexamic acid (TXA), a molecule that prevents plasminogen activation through blocking recruitment to target substrates, is the most widely used inhibitor for the plasminogen/plasmin system in therapeutics. However, TXA lacks efficacy on the active form of plasmin. Thus, there is a need to develop specific inhibitors that target the protease active site. Here we report the crystal structures of plasmin in complex with the novel YO ( trans -4-aminomethylcyclohexanecarbonyl-l-tyrosine- n -octylamide) class of small molecule inhibitors. We found that these inhibitors form key interactions with the S1 and S3' subsites of the catalytic cleft. Here, the TXA moiety of the YO compounds inserts into the primary (S1) specificity pocket, suggesting that TXA itself may function as a weak plasmin inhibitor, a hypothesis supported by subsequent biochemical and biophysical analyses. Mutational studies reveal that F587 of the S' subsite plays a key role in mediating the inhibitor interaction. Taken together, these data provide a foundation for the future development of small molecule inhibitors to specifically regulate plasmin function in a range of diseases and disorders.

Validation of the proteasome as a therapeutic target in Plasmodium using an epoxyketone inhibitor with parasite-specific toxicity

PubMed Central

Li, Hao; Ponder, Elizabeth L.; Verdoes, Martijn; Asbjornsdottir, Kristijana H.; Deu, Edgar; Edgington, Laura E.; Lee, Jeong Tae; Kirk, Christopher J.; Demo, Susan D.; Williamson, Kim C.; Bogyo, Matthew

2012-01-01

Summary The Plasmodium proteasome has been suggested to be a potential anti-malarial drug target, however toxicity of inhibitors has prevented validation of this enzyme in vivo. We report here a screen of a library of 670 analogs of the recently FDA approved inhibitor, carfilzomib, to identify compounds that selectively kill parasites. We identified one compound, PR3, that has significant parasite killing activity in vitro but dramatically reduced toxicity in host cells. We found that this parasite-specific toxicity is not due to selective targeting of the Plasmodium proteasome over the host proteasome, but instead is due to a lack of activity against one of the human proteasome subunits. Subsequently, we used PR3 to significantly reduce parasite load in P. berghei infected mice without host toxicity, thus validating the proteasome as a viable anti-malarial drug target. PMID:23142757

Lipid raft-like liposomes used for targeted delivery of a chimeric entry-inhibitor peptide with anti-HIV-1 activity.

PubMed

Gómara, María José; Pérez-Pomeda, Ignacio; Gatell, José María; Sánchez-Merino, Victor; Yuste, Eloisa; Haro, Isabel

2017-02-01

The work reports the design and synthesis of a chimeric peptide that is composed of the peptide sequences of two entry inhibitors which target different sites of HIV-1 gp41. The chimeric peptide offers the advantage of targeting two gp41 regions simultaneously: the fusion peptide and the loop both of which are membrane active and participate in the membrane fusion process. We therefore use lipid raft-like liposomes as a tool to specifically direct the chimeric inhibitor peptide to the membrane domains where the HIV-1 envelope protein is located. Moreover, the liposomes that mimic the viral membrane composition protect the chimeric peptide against proteolytic digestion thereby increasing the stability of the peptide. The described liposome preparations are suitable nanosystems for managing hydrophobic entry-inhibitor peptides as putative therapeutics. Copyright © 2016 Elsevier Inc. All rights reserved.

Small-Molecule Inhibitors Targeting DNA Repair and DNA Repair Deficiency in Research and Cancer Therapy.

PubMed

Hengel, Sarah R; Spies, M Ashley; Spies, Maria

2017-09-21

To maintain stable genomes and to avoid cancer and aging, cells need to repair a multitude of deleterious DNA lesions, which arise constantly in every cell. Processes that support genome integrity in normal cells, however, allow cancer cells to develop resistance to radiation and DNA-damaging chemotherapeutics. Chemical inhibition of the key DNA repair proteins and pharmacologically induced synthetic lethality have become instrumental in both dissecting the complex DNA repair networks and as promising anticancer agents. The difficulty in capitalizing on synthetically lethal interactions in cancer cells is that many potential targets do not possess well-defined small-molecule binding determinates. In this review, we discuss several successful campaigns to identify and leverage small-molecule inhibitors of the DNA repair proteins, from PARP1, a paradigm case for clinically successful small-molecule inhibitors, to coveted new targets, such as RAD51 recombinase, RAD52 DNA repair protein, MRE11 nuclease, and WRN DNA helicase. Copyright © 2017 Elsevier Ltd. All rights reserved.

Adaptive evolution and elucidating the potential inhibitor against schizophrenia to target DAOA (G72) isoforms.

PubMed

Sehgal, Sheikh Arslan; Mannan, Shazia; Kanwal, Sumaira; Naveed, Ishrat; Mir, Asif

2015-01-01

Schizophrenia (SZ), a chronic mental and heritable disorder characterized by neurophysiological impairment and neuropsychological abnormalities, is strongly associated with D-amino acid oxidase activator (DAOA, G72). Research studies emphasized that overexpression of DAOA may be responsible for improper functioning of neurotransmitters, resulting in neurological disorders like SZ. In the present study, a hybrid approach of comparative modeling and molecular docking followed by inhibitor identification and structure modeling was employed. Screening was performed by two-dimensional similarity search against selected inhibitor, keeping in view the physiochemical properties of the inhibitor. Here, we report an inhibitor compound which showed maximum binding affinity against four selected isoforms of DAOA. Docking studies revealed that Glu-53, Thr-54, Lys-58, Val-85, Ser-86, Tyr-87, Leu-88, Glu-90, Leu-95, Val-98, Ser-100, Glu-112, Tyr-116, Lys-120, Asp-121, and Arg-122 are critical residues for receptor-ligand interaction. The C-terminal of selected isoforms is conserved, and binding was observed on the conserved region of isoforms. We propose that selected inhibitor might be more potent on the basis of binding energy values. Further analysis of this inhibitor through site-directed mutagenesis could be helpful for exploring the details of ligand-binding pockets. Overall, the findings of this study may be helpful in designing novel therapeutic targets to cure SZ.

Adaptive evolution and elucidating the potential inhibitor against schizophrenia to target DAOA (G72) isoforms

PubMed Central

Sehgal, Sheikh Arslan; Mannan, Shazia; Kanwal, Sumaira; Naveed, Ishrat; Mir, Asif

2015-01-01

Schizophrenia (SZ), a chronic mental and heritable disorder characterized by neurophysiological impairment and neuropsychological abnormalities, is strongly associated with D-amino acid oxidase activator (DAOA, G72). Research studies emphasized that overexpression of DAOA may be responsible for improper functioning of neurotransmitters, resulting in neurological disorders like SZ. In the present study, a hybrid approach of comparative modeling and molecular docking followed by inhibitor identification and structure modeling was employed. Screening was performed by two-dimensional similarity search against selected inhibitor, keeping in view the physiochemical properties of the inhibitor. Here, we report an inhibitor compound which showed maximum binding affinity against four selected isoforms of DAOA. Docking studies revealed that Glu-53, Thr-54, Lys-58, Val-85, Ser-86, Tyr-87, Leu-88, Glu-90, Leu-95, Val-98, Ser-100, Glu-112, Tyr-116, Lys-120, Asp-121, and Arg-122 are critical residues for receptor–ligand interaction. The C-terminal of selected isoforms is conserved, and binding was observed on the conserved region of isoforms. We propose that selected inhibitor might be more potent on the basis of binding energy values. Further analysis of this inhibitor through site-directed mutagenesis could be helpful for exploring the details of ligand-binding pockets. Overall, the findings of this study may be helpful in designing novel therapeutic targets to cure SZ. PMID:26170631

Potential role for mammalian target of rapamycin inhibitors as first-line therapy in hormone receptor–positive advanced breast cancer

PubMed Central

Beck, J Thaddeus

2015-01-01

Despite advances in cytotoxic chemotherapy and targeted therapies, 5-year survival rates remain low for patients with advanced breast cancer at diagnosis. This highlights the limited effectiveness of current treatment options. An improved understanding of cellular functions associated with the development and progression of breast cancer has resulted in the creation of a number of novel targeted molecular therapies. However, more work is needed to improve outcomes, particularly in the first-line recurrent or metastatic hormone receptor–positive breast cancer setting. The phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (mTOR) pathway is a major intracellular signaling pathway that is often upregulated in breast cancer, and overactivation of this pathway has been associated with primary or developed resistance to endocrine treatment. Clinical data from the Phase III Breast Cancer Trials of Oral Everolimus-2 (BOLERO-2) study of the mTOR inhibitor everolimus combined with exemestane in hormone receptor–positive advanced breast cancer were very promising, highlighting the potential role of mTOR inhibitors in combination with endocrine therapies as a first-line treatment option for these patients. It is hoped that the use of mTOR inhibitors combined with current standard-of-care endocrine therapies, such as aromatase inhibitors, in the first-line advanced breast cancer setting may result in greater antitumor effects and also delay or reverse treatment resistance. PMID:26675495

Synergistic targeting of malignant pleural mesothelioma cells by MDM2 inhibitors and TRAIL agonists

PubMed Central

Urso, Loredana; Biasini, Lorena; Zago, Giulia; Calabrese, Fiorella; Conte, Pier Franco; Ciminale, Vincenzo; Pasello, Giulia

2017-01-01

Malignant Pleural Mesothelioma (MPM) is a chemoresistant tumor characterized by low rate of p53 mutation and upregulation of Murine Double Minute 2 (MDM2), suggesting that it may be effectively targeted using MDM2 inhibitors. In the present study, we investigated the anticancer activity of the MDM2 inhibitors Nutlin 3a (in vitro) and RG7112 (in vivo), as single agents or in combination with rhTRAIL. In vitro studies were performed using MPM cell lines derived from epithelioid (ZL55, M14K), biphasic (MSTO211H) and sarcomatoid (ZL34) MPMs. In vivo studies were conducted on a sarcomatoid MPM mouse model. In all the cell lines tested (with the exception of ZL55, which carries a biallelic loss-of-function mutation of p53), Nutlin 3a enhanced p21, MDM2 and DR5 expression, and decreased survivin expression. These changes were associated to cell cycle arrest but not to a significant induction of apoptosis. A synergistic pro-apoptotic effect was obtained through the association of rhTRAIL in all the cell lines harboring functional p53. This synergistic interaction of MDM2 inhibitor and TRAIL agonist was confirmed using a mouse preclinical model. Our results suggest that the combined targeting of MDM2 and TRAIL might provide a novel therapeutic option for treatment of MPM patients, particularly in the case of sarcomatoid MPM with MDM2 overexpression and functional inactivation of wild-type p53. PMID:28562336

MiR-214 regulates oral cancer KB cell apoptosis through targeting RASSF5.

PubMed

Li, T K; Yin, K; Chen, Z; Bao, Y; Zhang, S X

2017-03-08

Ras association domain family member 5 (RASSF5), a member of the Ras association domain family, induces cell apoptosis by phosphorylating FOXO3a, which triggers target gene BIM (pro-apoptotic factor) activation. MiR-214 is overexpressed in oral cancer tissue, indicating its possible involvement in oral cancer pathogenesis. Bioinformatics analysis has revealed a complimentary sequence between miR-214 and the 3'-UTR of RASSF5 mRNA. However, whether miR-124 regulates RASSF5 in oral cancer remains poorly understood. We aimed to investigate the role of miR-214 in RASSF5 expression regulation in oral cancer. Tumor and paracarcinoma tissues were obtained from 48 oral cancer patients to examine miR-214 and RASSF5 expression. The relationship between miR-214 and RASSF5 was investigated by dual luciferase reporter gene assay. Oral cancer KB cells were cultured in vitro and divided into inhibitor NC, miR-214 inhibitor, Scramble-pMD18, RASSF5-pMD18, and miR-214 inhibitor + RASSF5-pMD18 groups. Caspase 3 activity, cell apoptosis, and total protein expression were measured by spectrophotometry, flow cytometry, and western blot, respectively. MiR-214 expression was significantly increased, while that of RASSF5 decreased in oral cancer tumor tissues compared to paracarcinoma tissues. Luciferase assay showed that miR-214 suppressed RASSF5 expression by targeting its 3'-UTR. Down-regulation of miR-214 and/or enhancement of RASSF5 expression markedly increased FOXO3a phosphorylation, BIM expression, caspase 3 activity, and apoptosis. In conclusion, miR-214 expression was elevated and RASSF5 was down-regulated in oral cancer. Moreover, miR-214 regulated KB cell apoptosis through targeted inhibition of RASSF5 expression, FOXO3a phosphorylation, and BIM expression, suggesting its possible application as a novel therapeutic oral cancer target.

Synthesis and P1' SAR exploration of potent macrocyclic tissue factor-factor VIIa inhibitors

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

Ladziata, Vladimir; Glunz, Peter W.; Zou, Yan

Selective tissue factor-factor VIIa complex (TF-FVIIa) inhibitors are viewed as promising compounds for treating thrombotic disease. In this contribution, we describe multifaceted exploratory SAR studies of S1'-binding moieties within a macrocyclic chemotype aimed at replacing cyclopropyl sulfone P1' group. Over the course of the optimization efforts, the 1-(1H-tetrazol-5-yl)cyclopropane P1' substituent emerged as an improved alternative, offering increased metabolic stability and lower clearance, while maintaining excellent potency and selectivity.

Calculation of Absorbed Dose in Target Tissue and Equivalent Dose in Sensitive Tissues of Patients Treated by BNCT Using MCNP4C

NASA Astrophysics Data System (ADS)

Zamani, M.; Kasesaz, Y.; Khalafi, H.; Pooya, S. M. Hosseini

Boron Neutron Capture Therapy (BNCT) is used for treatment of many diseases, including brain tumors, in many medical centers. In this method, a target area (e.g., head of patient) is irradiated by some optimized and suitable neutron fields such as research nuclear reactors. Aiming at protection of healthy tissues which are located in the vicinity of irradiated tissue, and based on the ALARA principle, it is required to prevent unnecessary exposure of these vital organs. In this study, by using numerical simulation method (MCNP4C Code), the absorbed dose in target tissue and the equiavalent dose in different sensitive tissues of a patiant treated by BNCT, are calculated. For this purpose, we have used the parameters of MIRD Standard Phantom. Equiavelent dose in 11 sensitive organs, located in the vicinity of target, and total equivalent dose in whole body, have been calculated. The results show that the absorbed dose in tumor and normal tissue of brain equal to 30.35 Gy and 0.19 Gy, respectively. Also, total equivalent dose in 11 sensitive organs, other than tumor and normal tissue of brain, is equal to 14 mGy. The maximum equivalent doses in organs, other than brain and tumor, appear to the tissues of lungs and thyroid and are equal to 7.35 mSv and 3.00 mSv, respectively.

Identification and characterization of carprofen as a multi-target FAAH/COX inhibitor

PubMed Central

Favia, Angelo D.; Habrant, Damien; Scarpelli, Rita; Migliore, Marco; Albani, Clara; Bertozzi, Sine Mandrup; Dionisi, Mauro; Tarozzo, Glauco; Piomelli, Daniele; Cavalli, Andrea; De Vivo, Marco

2013-01-01

Pain and inflammation are major therapeutic areas for drug discovery. Current drugs for these pathologies have limited efficacy, however, and often cause a number of unwanted side effects. In the present study, we identify the non-steroid anti-inflammatory drug, carprofen, as a multi-target-directed ligand that simultaneously inhibits cyclooxygenase-1 (COX-1), COX-2 and fatty acid amide hydrolase (FAAH). Additionally, we synthesized and tested several racemic derivatives of carprofen, sharing this multi-target activity. This may result in improved analgesic efficacy and reduced side effects (Naidu, et al (2009) J Pharmacol Exp Ther 329, 48-56; Fowler, C.J. et al. (2012) J Enzym Inhib Med Chem Jan 6; Sasso, et al (2012) Pharmacol Res 65, 553). The new compounds are among the most potent multi-target FAAH/COXs inhibitors reported so far in the literature, and thus may represent promising starting points for the discovery of new analgesic and anti-inflammatory drugs. PMID:23043222

Brainstorming: weighted voting prediction of inhibitors for protein targets.

PubMed

Plewczynski, Dariusz

2011-09-01

The "Brainstorming" approach presented in this paper is a weighted voting method that can improve the quality of predictions generated by several machine learning (ML) methods. First, an ensemble of heterogeneous ML algorithms is trained on available experimental data, then all solutions are gathered and a consensus is built between them. The final prediction is performed using a voting procedure, whereby the vote of each method is weighted according to a quality coefficient calculated using multivariable linear regression (MLR). The MLR optimization procedure is very fast, therefore no additional computational cost is introduced by using this jury approach. Here, brainstorming is applied to selecting actives from large collections of compounds relating to five diverse biological targets of medicinal interest, namely HIV-reverse transcriptase, cyclooxygenase-2, dihydrofolate reductase, estrogen receptor, and thrombin. The MDL Drug Data Report (MDDR) database was used for selecting known inhibitors for these protein targets, and experimental data was then used to train a set of machine learning methods. The benchmark dataset (available at http://bio.icm.edu.pl/∼darman/chemoinfo/benchmark.tar.gz ) can be used for further testing of various clustering and machine learning methods when predicting the biological activity of compounds. Depending on the protein target, the overall recall value is raised by at least 20% in comparison to any single machine learning method (including ensemble methods like random forest) and unweighted simple majority voting procedures.

Targeting TORC1/2 enhances sensitivity to EGFR inhibitors in head and neck cancer preclinical models.

PubMed

Cassell, Andre; Freilino, Maria L; Lee, Jessica; Barr, Sharon; Wang, Lin; Panahandeh, Mary C; Thomas, Sufi M; Grandis, Jennifer R

2012-11-01

Head and neck squamous cell carcinoma (HNSCC) is characterized by overexpression of the epidermal growth factor receptor (EGFR) where treatments targeting EGFR have met with limited clinical success. Elucidation of the key downstream-pathways that remain activated in the setting of EGFR blockade may reveal new therapeutic targets. The present study was undertaken to test the hypothesis that inhibition of the mammalian target of rapamycin (mTOR) complex would enhance the effects of EGFR blockade in HNSCC preclinical models. Treatment of HNSCC cell lines with the newly developed TORC1/TORC2 inhibitor OSI-027/ASP4876 resulted in dose-dependent inhibition of proliferation with abrogation of phosphorylation of known downstream targets including phospho-AKT (Ser473), phospho-4E-BP1, phospho-p70s6K, and phospho-PRAS40. Furthermore, combined treatment with OSI-027 and erlotinib resulted in enhanced biochemical effects and synergistic growth inhibition in vitro. Treatment of mice bearing HNSCC xenografts with a combination of the Food and Drug Administration (FDA)-approved EGFR inhibitor cetuximab and OSI-027 demonstrated a significant reduction of tumor volumes compared with either treatment alone. These findings suggest that TORC1/TORC2 inhibition in conjunction with EGFR blockade represents a plausible therapeutic strategy for HNSCC.

Ligand-targeted delivery of small interfering RNAs to malignant cells and tissues.

PubMed

Thomas, Mini; Kularatne, Sumith A; Qi, Longwu; Kleindl, Paul; Leamon, Christopher P; Hansen, Michael J; Low, Philip S

2009-09-01

Potential clinical applications of small interfering RNA (siRNA) are hampered primarily by delivery issues. We have successfully addressed the delivery problems associated with off-site targeting of highly toxic chemotherapeutic agents by attaching the drugs to tumor-specific ligands that will carry the attached cargo into the desired cancer cell. Indeed, several such tumor-targeted drugs are currently undergoing human clinical trials. We now show that efficient targeting of siRNA to malignant cells and tissues can be achieved by covalent conjugation of small-molecular-weight, high-affinity ligands, such as folic acid and DUPA (2-[3-(1, 3-dicarboxy propyl)-ureido] pentanedioic acid), to siRNA. The former ligand binds a folate receptor that is overexpressed on a variety of cancers, whereas the latter ligand binds to prostate-specific membrane antigen that is overexpressed specifically on prostate cancers and the neovasculature of all solid tumors. Using these ligands, we show remarkable receptor-mediated targeting of siRNA to cancer tissues in vitro and in vivo.

NFκB inhibitors induce cell death in glioblastomas.

PubMed

Zanotto-Filho, Alfeu; Braganhol, Elizandra; Schröder, Rafael; de Souza, Luís Henrique T; Dalmolin, Rodrigo J S; Pasquali, Matheus A Bittencourt; Gelain, Daniel Pens; Battastini, Ana Maria Oliveira; Moreira, José Cláudio Fonseca

2011-02-01

Identification of novel target pathways in glioblastoma (GBM) remains critical due to poor prognosis, inefficient therapies and recurrence associated with these tumors. In this work, we evaluated the role of nuclear-factor-kappa-B (NFκB) in the growth of GBM cells, and the potential of NFκB inhibitors as antiglioma agents. NFκB pathway was found overstimulated in GBM cell lines and in tumor specimens compared to normal astrocytes and healthy brain tissues, respectively. Treatment of a panel of established GBM cell lines (U138MG, U87, U373 and C6) with pharmacological NFκB inhibitors (BAY117082, parthenolide, MG132, curcumin and arsenic trioxide) and NFκB-p65 siRNA markedly decreased the viability of GBMs as compared to inhibitors of other signaling pathways such as MAPKs (ERK, JNK and p38), PKC, EGFR and PI3K/Akt. In addition, NFκB inhibitors presented a low toxicity to normal astrocytes, indicating selectivity to cancerous cells. In GBMs, mitochondrial dysfunction (membrane depolarization, bcl-xL downregulation and cytochrome c release) and arrest in the G2/M phase were observed at the early steps of NFκB inhibitors treatment. These events preceded sub-G1 detection, apoptotic body formation and caspase-3 activation. Also, NFκB was found overstimulated in cisplatin-resistant C6 cells, and treatment of GBMs with NFκB inhibitors overcame cisplatin resistance besides potentiating the effects of the chemotherapeutics, cisplatin and doxorubicin. These findings support NFκB as a potential target to cell death induction in GBMs, and that the NFκB inhibitors may be considered for in vivo testing on animal models and possibly on GBM therapy. Copyright © 2010 Elsevier Inc. All rights reserved.

Structural investigation of inhibitor designs targeting 3-dehydroquinate dehydratase from the shikimate pathway of Mycobacterium tuberculosis

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

Dias, Marcio V.B.; Snee, William C.; Bromfield, Karen M.

The shikimate pathway is essential in Mycobacterium tuberculosis and its absence from humans makes the enzymes of this pathway potential drug targets. In the present paper, we provide structural insights into ligand and inhibitor binding to 3-dehydroquinate dehydratase (dehydroquinase) from M. tuberculosis (MtDHQase), the third enzyme of the shikimate pathway. The enzyme has been crystallized in complex with its reaction product, 3-dehydroshikimate, and with six different competitive inhibitors. The inhibitor 2,3-anhydroquinate mimics the flattened enol/enolate reaction intermediate and serves as an anchor molecule for four of the inhibitors investigated. MtDHQase also forms a complex with citrazinic acid, a planar analoguemore » of the reaction product. The structure of MtDHQase in complex with a 2,3-anhydroquinate moiety attached to a biaryl group shows that this group extends to an active-site subpocket inducing significant structural rearrangement. The flexible extensions of inhibitors designed to form {pi}-stacking interactions with the catalytic Tyr{sup 24} have been investigated. The high-resolution crystal structures of the MtDHQase complexes provide structural evidence for the role of the loop residues 19-24 in MtDHQase ligand binding and catalytic mechanism and provide a rationale for the design and efficacy of inhibitors.« less

Identification of beta-lactam antibiotics in tissue samples containing unknown microbial inhibitors.

PubMed

Moats, W A; Romanowski, R D; Medina, M B

1998-01-01

Antibiotic residues in animal tissues can be detected by various screening tests based on microbial inhibition. In the 7-plate assay used by the U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS), penicillinase is incorporated into all but one plate to distinguish beta-lactam antibiotics from other types. However, beta-lactams such as cloxacillin and the cephalosporins are resistant to degradation by penicillinase. They may not be identified as beta-lactams by this procedure, and thus, they may be identified as unidentified microbial inhibitors (UMIs). However, these penicillinase-resistant compounds can be degraded by other beta-lactamases. The present study describes an improved screening protocol to identify beta-lactam antibiotics classified as UMIs. A multiresidue liquid chromatographic procedure based on a method for determining beta-lactams in milk was also used to identify and quantitate residues. The 2 methods were tested with 24 tissue FSIS samples classified as containing UMIs. Of these, 3 contained penicillin G, including one at a violative level, and 5 contained a metabolite of ceftiofur. The others were negative for beta-lactam antibiotics.

Targeting Tumor-Associated Macrophages as a Potential Strategy to Enhance the Response to Immune Checkpoint Inhibitors.

PubMed

Cassetta, Luca; Kitamura, Takanori

2018-01-01

Inhibition of immune checkpoint pathways in CD8 + T cell is a promising therapeutic strategy for the treatment of solid tumors that has shown significant anti-tumor effects and is now approved by the FDA to treat patients with melanoma and lung cancer. However the response to this therapy is limited to a certain fraction of patients and tumor types, for reasons still unknown. To ensure success of this treatment, CD8 + T cells, the main target of the checkpoint inhibitors, should exert full cytotoxicity against tumor cells. However recent studies show that tumor-associated macrophages (TAM) can impede this process by different mechanisms. In this mini-review we will summarize recent studies showing the effect of TAM targeting on immune checkpoint inhibitors efficacy. We will also discuss on the limitations of the current strategies as well on the future scientific challenges for the progress of the tumor immunology field.

Identification of a Pyridoxine-Derived Small-Molecule Inhibitor Targeting Dengue Virus RNA-Dependent RNA Polymerase.

PubMed

Xu, Hong-Tao; Colby-Germinario, Susan P; Hassounah, Said; Quashie, Peter K; Han, Yingshan; Oliveira, Maureen; Stranix, Brent R; Wainberg, Mark A

2016-01-01

The viral RNA-dependent RNA polymerase (RdRp) activity of the dengue virus (DENV) NS5 protein is an attractive target for drug design. Here, we report the identification of a novel class of inhibitor (i.e., an active-site metal ion chelator) that acts against DENV RdRp activity. DENV RdRp utilizes a two-metal-ion mechanism of catalysis; therefore, we constructed a small library of compounds, through mechanism-based drug design, aimed at chelating divalent metal ions in the catalytic site of DENV RdRp. We now describe a pyridoxine-derived small-molecule inhibitor that targets DENV RdRp and show that 5-benzenesulfonylmethyl-3-hydroxy-4-hydroxymethyl-pyridine-2-carboxylic acid hydroxyamide (termed DMB220) inhibited the RdRp activity of DENV serotypes 1 to 4 at low micromolar 50% inhibitory concentrations (IC50s of 5 to 6.7 μM) in an enzymatic assay. The antiviral activity of DMB220 against DENV infection was also verified in a cell-based assay and showed a 50% effective concentration (EC50) of <3 μM. Enzyme assays proved that DMB220 was competitive with nucleotide incorporation. DMB220 did not inhibit the enzymatic activity of recombinant HIV-1 reverse transcriptase and showed only weak inhibition of HIV-1 integrase strand transfer activity, indicating high specificity for DENV RdRp. S600T substitution in the DENV RdRp, which was previously shown to confer resistance to nucleoside analogue inhibitors (NI), conferred 3-fold hypersusceptibility to DMB220, and enzymatic analyses showed that this hypersusceptibility may arise from the decreased binding/incorporation efficiency of the natural NTP substrate without significantly impacting inhibitor binding. Thus, metal ion chelation at the active site of DENV RdRp represents a viable anti-DENV strategy, and DMB220 is the first of a new class of DENV inhibitor. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs): Positive and negative regulators in tumor cell adhesion.

PubMed

Bourboulia, Dimitra; Stetler-Stevenson, William G

2010-06-01

Cells adhere to one another and/or to matrices that surround them. Regulation of cell-cell (intercellular) and cell-matrix adhesion is tightly controlled in normal cells, however, defects in cell adhesion are common in the majority of human cancers. Multilateral communication among tumor cells with the extracellular matrix (ECM) and neighbor cells is accomplished through adhesion molecules, ECM components, proteolytic enzymes and their endogenous inhibitors. There is sufficient evidence to suggest that reduced adherence is a tumor cell property engaged during tumor progression. Tumor cells acquire the ability to change shape, detach and easily move through spaces disorganizing the normal tissue architecture. This property is due to changes in expression levels of adhesion molecules and/or due to elevated levels of secreted proteolytic enzymes, including matrix metalloproteinases (MMPs). Among other roles, MMPs degrade the ECM and, therefore, prepare the path for tumor cells to migrate, invade and spread to distant secondary areas, where they form metastasis. Tissue inhibitors of metalloproteinases or TIMPs control MMP activities and, therefore, minimize matrix degradation. Both MMPs and TIMPs are involved in tissue remodeling and decisively regulate tumor cell progression including tumor angiogenesis. In this review, we describe and discuss data that support the important role of MMPs and TIMPs in cancer cell adhesion and tumor progression. Published by Elsevier Ltd.

Neuronal and Cardiovascular Potassium Channels as Therapeutic Drug Targets

PubMed Central

Humphries, Edward S. A.

2015-01-01

Potassium (K+) channels, with their diversity, often tissue-defined distribution, and critical role in controlling cellular excitability, have long held promise of being important drug targets for the treatment of dysrhythmias in the heart and abnormal neuronal activity within the brain. With the exception of drugs that target one particular class, ATP-sensitive K+ (KATP) channels, very few selective K+ channel activators or inhibitors are currently licensed for clinical use in cardiovascular and neurological disease. Here we review what a range of human genetic disorders have told us about the role of specific K+ channel subunits, explore the potential of activators and inhibitors of specific channel populations as a therapeutic strategy, and discuss possible reasons for the difficulty in designing clinically relevant K+ channel modulators. PMID:26303307

Identification of inhibitors for putative malaria drug targets amongst novel antimalarial compounds

PubMed Central

Crowther, Gregory J.; Napuli, Alberto J.; Gilligan, James H.; Gagaring, Kerstin; Borboa, Rachel; Francek, Carolyn; Chen, Zhong; Dagostino, Eleanor F.; Stockmyer, Justin B.; Wang, Yu; Rodenbough, Philip P.; Castaneda, Lisa J.; Leibly, David J.; Bhandari, Janhavi; Gelb, Michael H.; Brinker, Achim; Engels, Ingo; Taylor, Jennifer; Chatterjee, Arnab K.; Fantauzzi, Pascal; Glynne, Richard J.; Van Voorhis, Wesley C.; Kuhen, Kelli L.

2011-01-01

The efficacy of most marketed antimalarial drugs has been compromised by evolution of parasite resistance, underscoring an urgent need to find new drugs with new mechanisms of action. We have taken a high-throughput approach toward identifying novel antimalarial chemical inhibitors of prioritized drug targets for P. falciparum, excluding targets which are inhibited by currently used drugs. A screen of commercially available libraries identified 5,655 low molecular weight compounds that inhibit growth of P. falciparum cultures with EC50 values below 1.25 μM. These compounds were then tested in 384- or 1536-well biochemical assays for activity against nine Plasmodium enzymes: adenylosuccinate synthetase (AdSS), choline kinase (CK), deoxyuridine triphosphate nucleotidohydrolase (dUTPase), glutamate dehydrogenase (GDH), guanylate kinase (GK), N-myristoyltransferase (NMT), orotidine 5′-monophosphate decarboxylase (OMPDC), farnesyl pyrophosphate synthase (FPPS) and S-adenosylhomocysteine hydrolase (SAHH). These enzymes were selected using TDRtargets.org, and are believed to have excellent potential as drug targets based on criteria such as their likely essentiality, druggability, and amenability to high-throughput biochemical screening. Six of these targets were inhibited by one or more of the antimalarial scaffolds and may have potential use in drug development, further target validation studies and exploration of P. falciparum biochemistry and biology. PMID:20813141

Identification of inhibitors for putative malaria drug targets among novel antimalarial compounds.

PubMed

Crowther, Gregory J; Napuli, Alberto J; Gilligan, James H; Gagaring, Kerstin; Borboa, Rachel; Francek, Carolyn; Chen, Zhong; Dagostino, Eleanor F; Stockmyer, Justin B; Wang, Yu; Rodenbough, Philip P; Castaneda, Lisa J; Leibly, David J; Bhandari, Janhavi; Gelb, Michael H; Brinker, Achim; Engels, Ingo H; Taylor, Jennifer; Chatterjee, Arnab K; Fantauzzi, Pascal; Glynne, Richard J; Van Voorhis, Wesley C; Kuhen, Kelli L

2011-01-01

The efficacy of most marketed antimalarial drugs has been compromised by evolution of parasite resistance, underscoring an urgent need to find new drugs with new mechanisms of action. We have taken a high-throughput approach toward identifying novel antimalarial chemical inhibitors of prioritized drug targets for Plasmodium falciparum, excluding targets which are inhibited by currently used drugs. A screen of commercially available libraries identified 5655 low molecular weight compounds that inhibit growth of P. falciparum cultures with EC(50) values below 1.25μM. These compounds were then tested in 384- or 1536-well biochemical assays for activity against nine Plasmodium enzymes: adenylosuccinate synthetase (AdSS), choline kinase (CK), deoxyuridine triphosphate nucleotidohydrolase (dUTPase), glutamate dehydrogenase (GDH), guanylate kinase (GK), N-myristoyltransferase (NMT), orotidine 5'-monophosphate decarboxylase (OMPDC), farnesyl pyrophosphate synthase (FPPS) and S-adenosylhomocysteine hydrolase (SAHH). These enzymes were selected using TDRtargets.org, and are believed to have excellent potential as drug targets based on criteria such as their likely essentiality, druggability, and amenability to high-throughput biochemical screening. Six of these targets were inhibited by one or more of the antimalarial scaffolds and may have potential use in drug development, further target validation studies and exploration of P. falciparum biochemistry and biology. Copyright © 2010 Elsevier B.V. All rights reserved.

Effects of Steroidal Antiandrogen or 5-alpha-reductase Inhibitor on Prostate Tissue Hormone Content.

PubMed

Shibata, Yasuhiro; Arai, Seiji; Miyazawa, Yoshiyuki; Shuto, Takahiro; Nomura, Masashi; Sekine, Yoshitaka; Koike, Hidekazu; Matsui, Hiroshi; Ito, Kazuto; Suzuki, Kazuhiro

2017-05-01

The effects of a steroidal antiandrogen (AA) and 5-alpha-reductase inhibitor (5ARI) on prostate tissue hormone content and metabolism are not fully elucidated. The objective of this study is to investigate the hormone content and metabolism of the prostate tissues of patients treated with AA or 5ARI using the ultra-sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Thirty-nine patients with benign prostatic hyperplasia (BPH) undergoing transurethral surgery were included. Serum and prostate tissue hormone and prostate tissue hormone metabolism analyses were performed using LC-MS/MS after 1 month of treatment with chlormadinone acetate (CMA; steroidal AA, 50 mg/day) or dutasteride (DUTA; dual 5ARI, 0.5 mg/day). Serum testosterone (T), dihydrotestosterone (DHT), and adrenal androgen levels were lower in the CMA group than the control group. Prostate tissue T and DHT levels were also lower in the CMA group than the control group. In the DUTA group, only serum and prostate DHT concentrations were reduced compared to the control group; in contrast, those of other hormones, especially T and 4-androstene-3,17-dione in the prostate tissue, showed marked elevations up to 70.4- and 11.4-fold normal levels, respectively. Moreover, the hormone metabolism assay confirmed that the conversion of T to DHT was significantly suppressed while that of T to 4-androstene-3,17-dione was significantly accelerated in the prostate tissue of DUTA-treated patients. Although treatment with AA and 5ARI show similar clinical outcomes, their effect on tissue hormone content and metabolism varied greatly. Prostate 77: 672-680, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Chalcone-based small-molecule inhibitors attenuate malignant phenotype via targeting deubiquitinating enzymes

PubMed Central

Issaenko, Olga A.; Amerik, Alexander Yu

2012-01-01

The ubiquitin-proteasome system (UPS) is usurped by many if not all cancers to regulate their survival, proliferation, invasion, angiogenesis and metastasis. Bioflavonoids curcumin and chalcones exhibit anti-neoplastic selectivity through inhibition of the 26S proteasome-activity within the UPS. Here, we provide evidence for a novel mechanism of action of chalcone-based derivatives AM146, RA-9 and RA-14, which exert anticancer activity by targeting deubiquitinating enzymes (DUB) without affecting 20S proteasome catalytic-core activity. The presence of the α,β-unsaturated carbonyl group susceptible to nucleophilic attack from the sulfhydryl of cysteines in the active sites of DUB determines the capacity of novel small-molecules to act as cell-permeable, partly selective DUB inhibitors and induce rapid accumulation of polyubiquitinated proteins and deplete the pool of free ubiquitin. These chalcone-derivatives directly suppress activity of DUB UCH-L1, UCH-L3, USP2, USP5 and USP8, which are known to regulate the turnover and stability of key regulators of cell survival and proliferation. Inhibition of DUB-activity mediated by these compounds downregulates cell-cycle promoters, e.g., cyclin D1 and upregulates tumor suppressors p53, p27Kip1 and p16Ink4A. These changes are associated with arrest in S-G2/M, abrogated anchorage-dependent growth and onset of apoptosis in breast, ovarian and cervical cancer cells without noticeable alterations in primary human cells. Altogether, this work provides evidence of antitumor activity of novel chalcone-based derivatives mediated by their DUB-targeting capacity; supports the development of pharmaceuticals to directly target DUB as a most efficient strategy compared with proteasome inhibition and also provides a clear rationale for the clinical evaluation of these novel small-molecule DUB inhibitors. PMID:22510564

Matrix MetalloProteinases (MMPs) andTissue Inhibitors of MetalloProteinases (TIMPs): positive and negative regulators intumor cell adhesion

PubMed Central

Bourboulia, Dimitra; Stetler-Stevenson, William G.

2010-01-01

Cells adhere to one another and/or to matrices that surround them. Regulation of cell-cell (intercellular) and cell-matrix adhesion is tightly controlled in normal cells, however, defects in cell adhesion are common in the majority of humancancers. Multilateral communication among tumor cells with the extracellular matrix (ECM) and neighbor cells is accomplished through adhesion molecules, ECM components, proteolytic enzymes and their endogenous inhibitors. There is sufficient evidence to suggest that reduced adherence is a tumor cell propertyengaged during tumor progression. Tumor cells acquire the ability to change shape, detach and easily move through spaces disorganizing the normal tissue architecture. This property is due to changes in expression levels of adhesion molecules and/or due to elevated levels of secreted proteolytic enzymes, including matrix metalloproteinases (MMPs). Among other roles, MMPsdegrade the ECMand, therefore, prepare the path for tumor cells to migrate, invade and spread to distant secondary areas, where they form metastasis. Tissue Inhibitors of Metalloproteinases or TIMPs control MMP activities and, therefore, minimize matrix degradation. Both MMPs and TIMPs are involved in tissue remodeling and decisively regulate tumor cell progression including tumor angiogenesis. In this review, we describe and discuss data that support the important role of MMPs and TIMPs in cancer cell adhesion and tumor progression. PMID:20470890

Discovery – Targeted Treatments and mTOR Inhibitors

Cancer.gov

Thanks to discovering the anticancer effects of mTOR inhibitors, cancer treatment for pNet, a rare type of pancreatic cancer, were revolutionized. Through clinical trials, NCI continues to investigate the life-saving potential of mTOR inhibitors.

Three-Dimensionally Engineered Normal Human Lung Tissue-Like Assemblies: Target Tissues for Human Respiratory Viral Infections

NASA Technical Reports Server (NTRS)

Goodwin, Thomas J.; McCarthy, M.; Lin, Y-H.; Deatly, A. M.

2008-01-01

In vitro three-dimensional (3D) human lung epithelio-mesenchymal tissue-like assemblies (3D hLEM TLAs) from this point forward referred to as TLAs were engineered in Rotating Wall Vessel (RWV) technology to mimic the characteristics of in vivo tissues thus providing a tool to study human respiratory viruses and host cell interactions. The TLAs were bioengineered onto collagen-coated cyclodextran microcarriers using primary human mesenchymal bronchial-tracheal cells (HBTC) as the foundation matrix and an adult human bronchial epithelial immortalized cell line (BEAS-2B) as the overlying component. The resulting TLAs share significant characteristics with in vivo human respiratory epithelium including polarization, tight junctions, desmosomes, and microvilli. The presence of tissue-like differentiation markers including villin, keratins, and specific lung epithelium markers, as well as the production of tissue mucin, further confirm these TLAs differentiated into tissues functionally similar to in vivo tissues. Increasing virus titers for human respiratory syncytial virus (wtRSVA2) and the detection of membrane bound glycoproteins over time confirm productive infection with the virus. Therefore, we assert TLAs mimic aspects of the human respiratory epithelium and provide a unique capability to study the interactions of respiratory viruses and their primary target tissue independent of the host s immune system.

X-ray crystal structure of plasmin with tranexamic acid–derived active site inhibitors

PubMed Central

Wu, Guojie; Leung, Eleanor W. W.; Hidaka, Koushi; Quek, Adam J.; Caradoc-Davies, Tom T.; Jeevarajah, Devadharshini; Kirby, Nigel M.; Norton, Raymond S.; Tsuda, Yuko; Whisstock, James C.

2017-01-01

The zymogen protease plasminogen and its active form plasmin perform key roles in blood clot dissolution, tissue remodeling, cell migration, and bacterial pathogenesis. Dysregulation of the plasminogen/plasmin system results in life-threatening hemorrhagic disorders or thrombotic vascular occlusion. Accordingly, inhibitors of this system are clinically important. Currently, tranexamic acid (TXA), a molecule that prevents plasminogen activation through blocking recruitment to target substrates, is the most widely used inhibitor for the plasminogen/plasmin system in therapeutics. However, TXA lacks efficacy on the active form of plasmin. Thus, there is a need to develop specific inhibitors that target the protease active site. Here we report the crystal structures of plasmin in complex with the novel YO (trans-4-aminomethylcyclohexanecarbonyl-l-tyrosine-n-octylamide) class of small molecule inhibitors. We found that these inhibitors form key interactions with the S1 and S3′ subsites of the catalytic cleft. Here, the TXA moiety of the YO compounds inserts into the primary (S1) specificity pocket, suggesting that TXA itself may function as a weak plasmin inhibitor, a hypothesis supported by subsequent biochemical and biophysical analyses. Mutational studies reveal that F587 of the S′ subsite plays a key role in mediating the inhibitor interaction. Taken together, these data provide a foundation for the future development of small molecule inhibitors to specifically regulate plasmin function in a range of diseases and disorders. PMID:29296720

Programmed activation of cancer cell apoptosis: A tumor-targeted phototherapeutic topoisomerase I inhibitor

NASA Astrophysics Data System (ADS)

Shin, Weon Sup; Han, Jiyou; Kumar, Rajesh; Lee, Gyung Gyu; Sessler, Jonathan L.; Kim, Jong-Hoon; Kim, Jong Seung

2016-07-01

We report here a tumor-targeting masked phototherapeutic agent 1 (PT-1). This system contains SN-38—a prodrug of the topoisomerase I inhibitor irinotecan. Topoisomerase I is a vital enzyme that controls DNA topology during replication, transcription, and recombination. An elevated level of topoisomerase I is found in many carcinomas, making it an attractive target for the development of effective anticancer drugs. In addition, PT-1 contains both a photo-triggered moiety (nitrovanillin) and a cancer targeting unit (biotin). Upon light activation in cancer cells, PT-1 interferes with DNA re-ligation, diminishes the expression of topoisomerase I, and enhances the expression of inter alia mitochondrial apoptotic genes, death receptors, and caspase enzymes, inducing DNA damage and eventually leading to apoptosis. In vitro and in vivo studies showed significant inhibition of cancer growth and the hybrid system PT-1 thus shows promise as a programmed photo-therapeutic (“phototheranostic”).

Human melanoma cells resistant to MAPK inhibitors can be effectively targeted by inhibition of the p90 ribosomal S6 kinase

PubMed Central

Kosnopfel, Corinna; Sinnberg, Tobias; Sauer, Birgit; Niessner, Heike; Schmitt, Anja; Makino, Elena; Forschner, Andrea; Hailfinger, Stephan; Garbe, Claus; Schittek, Birgit

2017-01-01

The clinical availability of small molecule inhibitors specifically targeting mutated BRAF marked a significant breakthrough in melanoma therapy. Despite a dramatic anti-tumour activity and improved patient survival, rapidly emerging resistance, however, greatly limits the clinical benefit. The majority of the already described resistance mechanisms involve a reactivation of the MAPK signalling pathway. The p90 ribosomal S6 kinase (RSK), a downstream effector of the MAPK signalling cascade, has been reported to enhance survival of melanoma cells in response to chemotherapy. Here, we can show that RSK activity is significantly increased in human melanoma cells with acquired resistance to the BRAFV600E/K inhibitor vemurafenib. Interestingly, inhibition of RSK signalling markedly impairs the viability of vemurafenib resistant melanoma cells and is effective both in two-dimensional and in three-dimensional culture systems, especially in a chronic, long-term application. The effect of RSK inhibition can be partly replicated by downregulation of the well-known RSK target, Y-box binding protein 1 (YB-1). Intriguingly, RSK inhibition also retains its efficacy in melanoma cells with combined resistance to vemurafenib and the MEK inhibitor trametinib. These data suggest that active RSK signalling might be an attractive novel therapeutic target in melanoma with acquired resistance to MAPK pathway inhibitors. PMID:28415756

Naturally Occurring Mutations in the MPS1 Gene Predispose Cells to Kinase Inhibitor Drug Resistance.

PubMed

Gurden, Mark D; Westwood, Isaac M; Faisal, Amir; Naud, Sébastien; Cheung, Kwai-Ming J; McAndrew, Craig; Wood, Amy; Schmitt, Jessica; Boxall, Kathy; Mak, Grace; Workman, Paul; Burke, Rosemary; Hoelder, Swen; Blagg, Julian; Van Montfort, Rob L M; Linardopoulos, Spiros

2015-08-15

Acquired resistance to therapy is perhaps the greatest challenge to effective clinical management of cancer. With several inhibitors of the mitotic checkpoint kinase MPS1 in preclinical development, we sought to investigate how resistance against these inhibitors may arise so that mitigation or bypass strategies could be addressed as early as possible. Toward this end, we modeled acquired resistance to the MPS1 inhibitors AZ3146, NMS-P715, and CCT251455, identifying five point mutations in the kinase domain of MPS1 that confer resistance against multiple inhibitors. Structural studies showed how the MPS1 mutants conferred resistance by causing steric hindrance to inhibitor binding. Notably, we show that these mutations occur in nontreated cancer cell lines and primary tumor specimens, and that they also preexist in normal lymphoblast and breast tissues. In a parallel piece of work, we also show that the EGFR p.T790M mutation, the most common mutation conferring resistance to the EGFR inhibitor gefitinib, also preexists in cancer cells and normal tissue. Our results therefore suggest that mutations conferring resistance to targeted therapy occur naturally in normal and malignant cells and these mutations do not arise as a result of the increased mutagenic plasticity of cancer cells. ©2015 American Association for Cancer Research.

In Silico Screening for Inhibitors of P-Glycoprotein That Target the Nucleotide Binding Domains

PubMed Central

Brewer, Frances K.; Follit, Courtney A.; Vogel, Pia D.

2014-01-01

Multidrug resistances and the failure of chemotherapies are often caused by the expression or overexpression of ATP-binding cassette transporter proteins such as the multidrug resistance protein, P-glycoprotein (P-gp). P-gp is expressed in the plasma membrane of many cell types and protects cells from accumulation of toxins. P-gp uses ATP hydrolysis to catalyze the transport of a broad range of mostly hydrophobic compounds across the plasma membrane and out of the cell. During cancer chemotherapy, the administration of therapeutics often selects for cells which overexpress P-gp, thereby creating populations of cancer cells resistant to a variety of chemically unrelated chemotherapeutics. The present study describes extremely high-throughput, massively parallel in silico ligand docking studies aimed at identifying reversible inhibitors of ATP hydrolysis that target the nucleotide-binding domains of P-gp. We used a structural model of human P-gp that we obtained from molecular dynamics experiments as the protein target for ligand docking. We employed a novel approach of subtractive docking experiments that identified ligands that bound predominantly to the nucleotide-binding domains but not the drug-binding domains of P-gp. Four compounds were found that inhibit ATP hydrolysis by P-gp. Using electron spin resonance spectroscopy, we showed that at least three of these compounds affected nucleotide binding to the transporter. These studies represent a successful proof of principle demonstrating the potential of targeted approaches for identifying specific inhibitors of P-gp. PMID:25270578

Role of mineralization inhibitors in the regulation of hard tissue biomineralization: relevance to initial enamel formation and maturation

PubMed Central

Margolis, Henry C.; Kwak, Seo-Young; Yamazaki, Hajime

2014-01-01

Vertebrate mineralized tissues, i.e., enamel, dentin, cementum, and bone, have unique hierarchical structures and chemical compositions. Although these tissues are similarly comprised of a crystalline calcium apatite mineral phase and a protein component, they differ with respect to crystal size and shape, level and distribution of trace mineral ions, the nature of the proteins present, and their relative proportions of mineral and protein components. Despite apparent differences, mineralized tissues are similarly derived by highly concerted extracellular processes involving matrix proteins, proteases, and mineral ion fluxes that collectively regulate the nucleation, growth and organization of forming mineral crystals. Nature, however, provides multiple ways to control the onset, rate, location, and organization of mineral deposits in developing mineralized tissues. Although our knowledge is quite limited in some of these areas, recent evidence suggests that hard tissue formation is, in part, controlled through the regulation of specific molecules that inhibit the mineralization process. This paper addresses the role of mineralization inhibitors in the regulation of biological mineralization with emphasis on the relevance of current findings to the process of amelogenesis. Mineralization inhibitors can also serve to maintain driving forces for calcium phosphate precipitation and prevent unwanted mineralization. Recent evidence shows that native phosphorylated amelogenins have the capacity to prevent mineralization through the stabilization of an amorphous calcium phosphate precursor phase, as observed in vitro and in developing teeth. Based on present findings, the authors propose that the transformation of initially formed amorphous mineral deposits to enamel crystals is an active process associated with the enzymatic processing of amelogenins. Such processing may serve to control both initial enamel crystal formation and subsequent maturation. PMID:25309443

A novel angiogenesis inhibitor impairs lovo cell survival via targeting against human VEGFR and its signaling pathway of phosphorylation

PubMed Central

Zhang, Y M; Dai, B L; Zheng, L; Zhan, Y Z; Zhang, J; Smith, W W; Wang, X L; Chen, Y N; He, L C

2012-01-01

Colorectal cancer represents the fourth commonest malignancy, and constitutes a major cause of significant morbidity and mortality among other diseases. However, the chemical therapy is still under development. Angiogenesis plays an important role in colon cancer development. We developed HMQ18–22 (a novel analog of taspine) with the aim to target angiogenesis. We found that HMQ18–22 significantly reduced angiogenesis of chicken chorioallantoic membrane (CAM) and mouse colon tissue, and inhibited cell migration and tube formation as well. Then, we verified the interaction between HMQ18–22 and VEGFR2 by AlphaScreen P-VEGFR assay, screened the targets on angiogenesis by VEGF Phospho Antibody Array, validated the target by western blot and RNAi in lovo cells. We found HMQ18–22 could decrease phosphorylation of VEGFR2(Tyr1214), VEGFR1(Tyr1333), Akt(Tyr326), protein kinase Cα (PKCα) (Tyr657) and phospholipase-Cγ-1 (PLCγ-1) (Tyr771). Most importantly, HMQ18–22 inhibited proliferation of lovo cell and tumor growth in a human colon tumor xenografted model of athymic mice. Compared with normal lovo cells proliferation, the inhibition on proliferation of knockdown cells (VEGFR2, VEGFR1, Akt, PKCα and PLCγ-1) by HMQ18–22 decreased. These results suggested that HMQ18–22 is a novel angiogenesis inhibitor and can be a useful therapeutic candidate for colon cancer intervention. PMID:23059825

Targeting the ubiquitin-proteasome system for cancer treatment: discovering novel inhibitors from nature and drug repurposing.

PubMed

Soave, Claire L; Guerin, Tracey; Liu, Jinbao; Dou, Q Ping

2017-12-01

In the past 15 years, the proteasome has been validated as an anti-cancer drug target and 20S proteasome inhibitors (such as bortezomib and carfilzomib) have been approved by the FDA for the treatment of multiple myeloma and some other liquid tumors. However, there are shortcomings of clinical proteasome inhibitors, including severe toxicity, drug resistance, and no effect in solid tumors. At the same time, extensive research has been conducted in the areas of natural compounds and old drug repositioning towards the goal of discovering effective, economical, low toxicity proteasome-inhibitory anti-cancer drugs. A variety of dietary polyphenols, medicinal molecules, metallic complexes, and metal-binding compounds have been found to be able to selectively inhibit tumor cellular proteasomes and induce apoptotic cell death in vitro and in vivo, supporting the clinical success of specific 20S proteasome inhibitors bortezomib and carfilzomib. Therefore, the discovery of natural proteasome inhibitors and researching old drugs with proteasome-inhibitory properties may provide an alternative strategy for improving the current status of cancer treatment and even prevention.

HDAC Inhibitors Target Replication Forks to Take a Stab at Cancer | Center for Cancer Research

Cancer.gov

The stability and function of many proteins within the cell can be altered with the addition or removal of certain chemical groups, including acetyl groups. Therefore, the enzymes that regulate these modifications have an important impact on the cell. One class of such enzymes—histone deacetylases, or HDACs—has been implicated in cancer and has become a target for cancer therapy. One HDAC inhibitor, called SAHA, has been approved for use against cutaneous T-cell lymphoma, and more than 60 ongoing clinical trials are continuing to test this class of drugs in various forms of cancer. However, the mechanisms by which SAHA and other HDAC inhibitors undermine the viability of tumor cells are not completely understood.

Smad signaling pathway is a pivotal component of tissue inhibitor of metalloproteinases-3 regulation by transforming growth factor beta in human chondrocytes.

PubMed

Qureshi, Hamid Yaqoob; Ricci, Gemma; Zafarullah, Muhammad

2008-09-01

Transforming growth factor beta (TGF-beta1) promotes cartilage matrix synthesis and induces tissue inhibitor of metalloproteinases-3 (TIMP-3), which inhibits matrix metalloproteinases, aggrecanases and TNF-alpha-converting enzyme implicated in articular cartilage degradation and joint inflammation. TGF-beta1 activates Akt, ERK and Smad2 pathways in chondrocytes. Here we investigated previously unexplored roles of specific Smads in TGF-beta1 induction of TIMP-3 gene by pharmacological and genetic knockdown approaches. TGF-beta1-induced Smad2 phosphorylation and TIMP-3 protein expression could be inhibited by the Smad2/3 phosphorylation inhibitors, PD169316 and SB203580 and by Smad2-specific siRNA. Specific inhibitor of Smad3 (SIS3) and Smad3 siRNA abolished TGF-beta induction of TIMP-3. Smad2/3 siRNAs also down regulated TIMP-3 promoter-driven luciferase activities, suggesting transcriptional regulation. SiRNA-driven co-Smad4 knockdown abrogated TIMP-3 augmentation by TGF-beta. TIMP-3 promoter deletion analysis revealed that -828 deletion retains the original promoter activity while -333 and -167 deletions display somewhat reduced activity suggesting that most of the TGF-beta-responsive, cis-acting elements are found in the -333 fragment. Chromatin Immunoprecipitation (ChIP) analysis confirmed binding of Smad2 and Smad4 with the -940 and -333 promoter sequences. These results suggest that receptor-activated Smad2 and Smad3 and co-Smad4 critically mediate TGF-beta-stimulated TIMP-3 expression in human chondrocytes and TIMP-3 gene is a target of Smad signaling pathway.

Topoisomerase II Inhibitors and Poisons, and the Influence of Cell Cycle Checkpoints.

PubMed

D Arcy, Nicholas; Gabrielli, Brian

2017-01-01

Interactions between the decatenation checkpoint and Topoisomerase II (TopoII) are vital for maintaining integrity of the genome. Agents that target this enzyme have been in clinical use in cancer therapy for over 30 years with great success. The types of compounds that have been developed to target TopoII are broadly divided into poisons and catalytic inhibitors. The TopoII poisons are in clinical use as anti-cancer therapies, although in common to most chemotherapeutic agents, they display considerable normal tissue toxicity. Inhibition of the TopoIIb isoform has been implicated in this cytotoxicity. Response to TopoII active agents is determined by several factors, but cell cycle checkpoints play a large role in sensitivity and resistance. The G2/M phase checkpoints are of particular importance in considering the effectiveness of these drugs and are reviewed in this article. Functionality of the ATM dependent decatenation checkpoint may represent a new avenue for selective cancer therapy. Here we review the function of TopoII, the anti-cancer mechanisms and limitations of current catalytic inhibitors and poisons, and their influence on cell cycle checkpoints. We will also assess potential new mechanisms for targeting this enzyme to limit normal tissue toxicity, and how the cell cycle checkpoint triggered by these drugs may provide an alternative and possibly better target for novel therapies. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Targeting TORC1/2 Enhances Sensitivity to EGFR Inhibitors in Head and Neck Cancer Preclinical Models1

PubMed Central

Cassell, Andre; Freilino, Maria L; Lee, Jessica; Barr, Sharon; Wang, Lin; Panahandeh, Mary C; Thomas, Sufi M; Grandis, Jennifer R

2012-01-01

Head and neck squamous cell carcinoma (HNSCC) is characterized by overexpression of the epidermal growth factor receptor (EGFR) where treatments targeting EGFR have met with limited clinical success. Elucidation of the key downstream-pathways that remain activated in the setting of EGFR blockade may reveal new therapeutic targets. The present study was undertaken to test the hypothesis that inhibition of the mammalian target of rapamycin (mTOR) complex would enhance the effects of EGFR blockade in HNSCC preclinical models. Treatment of HNSCC cell lines with the newly developed TORC1/TORC2 inhibitor OSI-027/ASP4876 resulted in dose-dependent inhibition of proliferation with abrogation of phosphorylation of known downstream targets including phospho-AKT (Ser473), phospho-4E-BP1, phospho-p70s6K, and phospho-PRAS40. Furthermore, combined treatment with OSI-027 and erlotinib resulted in enhanced biochemical effects and synergistic growth inhibition in vitro. Treatment of mice bearing HNSCC xenografts with a combination of the Food and Drug Administration (FDA)-approved EGFR inhibitor cetuximab and OSI-027 demonstrated a significant reduction of tumor volumes compared with either treatment alone. These findings suggest that TORC1/TORC2 inhibition in conjunction with EGFR blockade represents a plausible therapeutic strategy for HNSCC. PMID:23226094

Arginine-specific gingipains from Porphyromonas gingivalis deprive protective functions of secretory leucocyte protease inhibitor in periodontal tissue

PubMed Central

Into, T; Inomata, M; Kanno, Y; Matsuyama, T; Machigashira, M; Izumi, Y; Imamura, T; Nakashima, M; Noguchi, T; Matsushita, K

2006-01-01

Chronic periodontitis is correlated with Porphyromonas gingivalis infection. In this study, we found that the expression of secretory leucocyte protease inhibitor (SLPI), an endogenous inhibitor for neutrophil-derived proteases, was reduced in gingival tissues with chronic periodontitis associated with P. gingivalis infection. The addition of vesicles of P. gingivalis decreased the amount of SLPI in the media of primary human gingival keratinocytes compared to untreated cultures. We therefore investigated how arginine-specific gingipains (Rgps) affect the functions of SLPI, because Rgps are the major virulence factors in the vesicles and cleave a wide range of in-host proteins. We found that Rgps digest SLPI in vitro, suppressing the release of SLPI. Rgps proteolysis of SLPI disrupted SLPI functions, which normally suppresses neutrophil elastase and neutralizes pro-inflammatory effects of bacterial cell wall compounds in cultured human gingival fibroblasts. The protease inhibitory action of SLPI was not exerted towards Rgps. These results suggest that Rgps reduce the protective effects of SLPI on neutrophil proteases and bacterial proinflammatory compounds, by which disease in gingival tissue may be accelerated at the sites with P. gingivalis infection. PMID:16907925

PI3K inhibitors as new cancer therapeutics: implications for clinical trial design

PubMed Central

Massacesi, Cristian; Di Tomaso, Emmanuelle; Urban, Patrick; Germa, Caroline; Quadt, Cornelia; Trandafir, Lucia; Aimone, Paola; Fretault, Nathalie; Dharan, Bharani; Tavorath, Ranjana; Hirawat, Samit

2016-01-01

The PI3K–AKT–mTOR pathway is frequently activated in cancer. PI3K inhibitors, including the pan-PI3K inhibitor buparlisib (BKM120) and the PI3Kα-selective inhibitor alpelisib (BYL719), currently in clinical development by Novartis Oncology, may therefore be effective as anticancer agents. Early clinical studies with PI3K inhibitors have demonstrated preliminary antitumor activity and acceptable safety profiles. However, a number of unanswered questions regarding PI3K inhibition in cancer remain, including: what is the best approach for different tumor types, and which biomarkers will accurately identify the patient populations most likely to benefit from specific PI3K inhibitors? This review summarizes the strategies being employed by Novartis Oncology to help maximize the benefits of clinical studies with buparlisib and alpelisib, including stratification according to PI3K pathway activation status, selective enrollment/target enrichment (where patients with PI3K pathway-activated tumors are specifically recruited), nonselective enrollment with mandatory tissue collection, and enrollment of patients who have progressed on previous targeted agents, such as mTOR inhibitors or endocrine therapy. An overview of Novartis-sponsored and Novartis-supported trials that are utilizing these approaches in a range of cancer types, including breast cancer, head and neck squamous cell carcinoma, non-small cell lung carcinoma, lymphoma, and glioblastoma multiforme, is also described. PMID:26793003

Tissue Inhibitor of Matrix Metalloproteinase-1 Promotes Myocardial Fibrosis by Mediating CD63-Integrin β1 Interaction.

PubMed

Takawale, Abhijit; Zhang, Pu; Patel, Vaibhav B; Wang, Xiuhua; Oudit, Gavin; Kassiri, Zamaneh

2017-06-01

Myocardial fibrosis is excess accumulation of the extracellular matrix fibrillar collagens. Fibrosis is a key feature of various cardiomyopathies and compromises cardiac systolic and diastolic performance. TIMP1 (tissue inhibitor of metalloproteinase-1) is consistently upregulated in myocardial fibrosis and is used as a marker of fibrosis. However, it remains to be determined whether TIMP1 promotes tissue fibrosis by inhibiting extracellular matrix degradation by matrix metalloproteinases or via an matrix metalloproteinase-independent pathway. We examined the function of TIMP1 in myocardial fibrosis using Timp1 -deficient mice and 2 in vivo models of myocardial fibrosis (angiotensin II infusion and cardiac pressure overload), in vitro analysis of adult cardiac fibroblasts, and fibrotic myocardium from patients with dilated cardiomyopathy (DCM). Timp1 deficiency significantly reduced myocardial fibrosis in both in vivo models of cardiomyopathy. We identified a novel mechanism for TIMP1 action whereby, independent from its matrix metalloproteinase-inhibitory function, it mediates an association between CD63 (cell surface receptor for TIMP1) and integrin β1 on cardiac fibroblasts, initiates activation and nuclear translocation of Smad2/3 and β-catenin, leading to de novo collagen synthesis. This mechanism was consistently observed in vivo, in cultured cardiac fibroblasts, and in human fibrotic myocardium. In addition, after long-term pressure overload, Timp1 deficiency persistently reduced myocardial fibrosis and ameliorated diastolic dysfunction. This study defines a novel matrix metalloproteinase-independent function of TIMP1 in promoting myocardial fibrosis. As such targeting TIMP1 could prove to be a valuable approach in developing antifibrosis therapies. © 2017 American Heart Association, Inc.

Glyceroneogenesis is inhibited through HIV protease inhibitor-induced inflammation in human subcutaneous but not visceral adipose tissue

PubMed Central

Leroyer, Stéphanie; Vatier, Camille; Kadiri, Sarah; Quette, Joëlle; Chapron, Charles; Capeau, Jacqueline; Antoine, Bénédicte

2011-01-01

Glyceroneogenesis, a metabolic pathway that participates during lipolysis in the recycling of free fatty acids to triglycerides into adipocytes, contributes to the lipid-buffering function of adipose tissue. We investigated whether glyceroneogenesis could be affected by human immunodeficiency virus (HIV) protease inhibitors (PIs) responsible or not for dyslipidemia in HIV-infected patients. We treated explants obtained from subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) depots from lean individuals. We observed that the dyslipidemic PIs nelfinavir, lopinavir and ritonavir, but not the lipid-neutral PI atazanavir, increased lipolysis and decreased glyceroneogenesis, leading to an increased release of fatty acids from SAT but not from VAT. At the same time, dyslipidemic PIs decreased the amount of perilipin and increased interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) secretion in SAT but not in VAT. Parthenolide, an inhibitor of the NFκB pathway, counteracted PI-induced increased inflammation and decreased glyceroneogenesis. IL-6 (100 ng) inhibited the activity of phosphoenolpyruvate carboxykinase, the key enzyme of glyceroneogenesis, in SAT but not in VAT. Our data show that dyslipidemic but not lipid-neutral PIs decreased glyceroneogenesis as a consequence of PI-induced increased inflammation in SAT that could have an affect on adipocytes and/or macrophages. These results add a new link between fat inflammation and increased fatty acids release and suggest a greater sensitivity of SAT than VAT to PI-induced inflammation. PMID:21068005

Targeting DDX3 with a small molecule inhibitor for lung cancer therapy

PubMed Central

Bol, Guus M; Vesuna, Farhad; Xie, Min; Zeng, Jing; Aziz, Khaled; Gandhi, Nishant; Levine, Anne; Irving, Ashley; Korz, Dorian; Tantravedi, Saritha; Heerma van Voss, Marise R; Gabrielson, Kathleen; Bordt, Evan A; Polster, Brian M; Cope, Leslie; van der Groep, Petra; Kondaskar, Atul; Rudek, Michelle A; Hosmane, Ramachandra S; van der Wall, Elsken; van Diest, Paul J; Tran, Phuoc T; Raman, Venu

2015-01-01

Lung cancer is the most common malignancy worldwide and is a focus for developing targeted therapies due to its refractory nature to current treatment. We identified a RNA helicase, DDX3, which is overexpressed in many cancer types including lung cancer and is associated with lower survival in lung cancer patients. We designed a first-in-class small molecule inhibitor, RK-33, which binds to DDX3 and abrogates its activity. Inhibition of DDX3 by RK-33 caused G1 cell cycle arrest, induced apoptosis, and promoted radiation sensitization in DDX3-overexpressing cells. Importantly, RK-33 in combination with radiation induced tumor regression in multiple mouse models of lung cancer. Mechanistically, loss of DDX3 function either by shRNA or by RK-33 impaired Wnt signaling through disruption of the DDX3–β-catenin axis and inhibited non-homologous end joining—the major DNA repair pathway in mammalian somatic cells. Overall, inhibition of DDX3 by RK-33 promotes tumor regression, thus providing a compelling argument to develop DDX3 inhibitors for lung cancer therapy. PMID:25820276

Adipocyte fatty acid binding protein 4 (FABP4) inhibitors. A comprehensive systematic review.

PubMed

Floresta, Giuseppe; Pistarà, Venerando; Amata, Emanuele; Dichiara, Maria; Marrazzo, Agostino; Prezzavento, Orazio; Rescifina, Antonio

2017-09-29

Small molecule inhibitors of adipocyte fatty acid binding protein 4 (FABP4) have attracted interest following the recent publications of beneficial pharmacological effects of these compounds. FABP4 is predominantly expressed in macrophages and adipose tissue where it regulates fatty acids (FAs) storage and lipolysis and is an important mediator of inflammation. In the past years, hundreds FABP4 inhibitors have been synthesized for effective atherosclerosis and diabetes treatments, including derivatives of niacin, quinoxaline, aryl-quinoline, bicyclic pyridine, urea, aromatic compounds and other novel heterocyclic compounds. This review provides an overview of the synthesized and discovered molecules as adipocyte fatty acid binding protein 4 inhibitors (FABP4is) since the synthesis of the putative FABP4i, BMS309403, highlighting the interactions of the different classes of inhibitors with the targets. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

New small-molecule inhibitor class targeting human immunodeficiency virus type 1 virion maturation.

PubMed

Blair, Wade S; Cao, Joan; Fok-Seang, Juin; Griffin, Paul; Isaacson, Jason; Jackson, R Lynn; Murray, Edward; Patick, Amy K; Peng, Qinghai; Perros, Manos; Pickford, Chris; Wu, Hua; Butler, Scott L

2009-12-01

A new small-molecule inhibitor class that targets virion maturation was identified from a human immunodeficiency virus type 1 (HIV-1) antiviral screen. PF-46396, a representative molecule, exhibits antiviral activity against HIV-1 laboratory strains and clinical isolates in T-cell lines and peripheral blood mononuclear cells (PBMCs). PF-46396 specifically inhibits the processing of capsid (CA)/spacer peptide 1 (SP1) (p25), resulting in the accumulation of CA/SP1 (p25) precursor proteins and blocked maturation of the viral core particle. Viral variants resistant to PF-46396 contain a single amino acid substitution in HIV-1 CA sequences (CAI201V), distal to the CA/SP1 cleavage site in the primary structure, which we demonstrate is sufficient to confer significant resistance to PF-46396 and 3-O-(3',3'-dimethylsuccinyl) betulinic acid (DSB), a previously described maturation inhibitor. Conversely, a single amino substitution in SP1 (SP1A1V), which was previously associated with DSB in vitro resistance, was sufficient to confer resistance to DSB and PF-46396. Further, the CAI201V substitution restored CA/SP1 processing in HIV-1-infected cells treated with PF-46396 or DSB. Our results demonstrate that PF-46396 acts through a mechanism that is similar to DSB to inhibit the maturation of HIV-1 virions. To our knowledge, PF-46396 represents the first small-molecule HIV-1 maturation inhibitor that is distinct in chemical class from betulinic acid-derived maturation inhibitors (e.g., DSB), demonstrating that molecules of diverse chemical classes can inhibit this mechanism.

Investigations of the Cavitation and Damage Thresholds of Histotripsy and Applications in Targeted Tissue Ablation

NASA Astrophysics Data System (ADS)

Vlaisavljevich, Eli

Histotripsy is a noninvasive ultrasound therapy that controls acoustic cavitation to mechanically fractionate soft tissue. This dissertation investigates the physical thresholds to initiate cavitation and produce tissue damage in histotripsy and factors affecting these thresholds in order to develop novel strategies for targeted tissue ablation. In the first part of this dissertation, the effects of tissue properties on histotripsy cavitation thresholds and damage thresholds were investigated. Results demonstrated that the histotripsy shock scattering threshold using multi-cycle pulses increases in stiffer tissues, while the histotripsy intrinsic threshold using single-cycle pulses is independent of tissue stiffness. Further, the intrinsic threshold slightly decreases with lower frequencies and significantly decreases with increasing temperature. The effects of tissue properties on the susceptibility to histotripsy-induced tissue damage were also investigated, demonstrating that stiffer tissues are more resistant to histotripsy. Two strategies were investigated for increasing the effectiveness of histotripsy for the treatment of stiffer tissues, with results showing that thermal preconditioning may be used to alter tissue susceptibility to histotripsy and that lower frequency treatments may increase the efficiency of histotripsy tissue ablation due to enhanced bubble expansion. In the second part of this dissertation, the feasibility of using histotripsy for targeted liver ablation was investigated in an intact in vivo porcine model, with results demonstrating that histotripsy was capable of non-invasively creating precise lesions throughout the entire liver. Additionally, a tissue selective ablation approach was developed, where histotripsy completely fractionated the liver tissue surrounding the major hepatic vessels and gallbladder while being self-limited at the boundaries of these critical structures. Finally, the long-term effects of histotripsy liver

Inhibitors of V-ATPases: old and new players.

PubMed

Huss, Markus; Wieczorek, Helmut

2009-02-01

V-ATPases constitute a ubiquitous family of heteromultimeric, proton translocating proteins. According to their localization in a multitude of eukaryotic endomembranes and plasma membranes, they energize many different transport processes. Currently, a handful of specific inhibitors of the V-ATPase are known, which represent valuable tools for the characterization of transport processes on the level of tissues, single cells or even purified proteins. The understanding of how these inhibitors function may provide a basis to develop new drugs for the benefit of patients suffering from diseases such as osteoporosis or cancer. For this purpose, it appears absolutely essential to determine the exact inhibitor binding site in a target protein on the one side and to uncover the crucial structural elements of an inhibitor on the other side. However, even for some of the most popular and long known V-ATPase inhibitors, such as bafilomycin or concanamycin, the authentic structures of their binding sites are elusive. The aim of this review is to summarize the recent advances for the old players in the inhibition game, the plecomacrolides bafilomycin and concanamycin, and to introduce some of the new players, the macrolacton archazolid, the benzolactone enamides salicylihalamide, lobatamide, apicularen, oximidine and cruentaren, and the indolyls.

Design, construction and performance evaluation of the target tissue thickness measurement system in intraoperative radiotherapy for breast cancer

NASA Astrophysics Data System (ADS)

Yazdani, Mohammad Reza; Setayeshi, Saeed; Arabalibeik, Hossein; Akbari, Mohammad Esmaeil

2017-05-01

Intraoperative electron radiation therapy (IOERT), which uses electron beams for irradiating the target directly during the surgery, has the advantage of delivering a homogeneous dose to a controlled layer of tissue. Since the dose falls off quickly below the target thickness, the underlying normal tissues are spared. In selecting the appropriate electron energy, the accuracy of the target tissue thickness measurement is critical. In contrast to other procedures applied in IOERT, the routine measurement method is considered to be completely traditional and approximate. In this work, a novel mechanism is proposed for measuring the target tissue thickness with an acceptable level of accuracy. An electronic system has been designed and manufactured with the capability of measuring the tissue thickness based on the recorded electron density under the target. The results indicated the possibility of thickness measurement with a maximum error of 2 mm for 91.35% of data. Aside from system limitation in estimating the thickness of 5 mm phantom, for 88.94% of data, maximum error is 1 mm.

Discovery of Novel Irreversible Inhibitors of Interleukin (IL)-2-inducible Tyrosine Kinase (Itk) by Targeting Cysteine 442 in the ATP Pocket

PubMed Central

Harling, John D.; Deakin, Angela M.; Campos, Sébastien; Grimley, Rachel; Chaudry, Laiq; Nye, Catherine; Polyakova, Oxana; Bessant, Christina M.; Barton, Nick; Somers, Don; Barrett, John; Graves, Rebecca H.; Hanns, Laura; Kerr, William J.; Solari, Roberto

2013-01-01

IL-2-inducible tyrosine kinase (Itk) plays a key role in antigen receptor signaling in T cells and is considered an important target for anti-inflammatory drug discovery. In order to generate inhibitors with the necessary potency and selectivity, a compound that targeted cysteine 442 in the ATP binding pocket and with an envisaged irreversible mode of action was designed. We incorporated a high degree of molecular recognition and specific design features making the compound suitable for inhaled delivery. This study confirms the irreversible covalent binding of the inhibitor to the kinase by x-ray crystallography and enzymology while demonstrating potency, selectivity, and prolonged duration of action in in vitro biological assays. The biosynthetic turnover of the kinase was also examined as a critical factor when designing irreversible inhibitors for extended duration of action. The exemplified Itk inhibitor demonstrated inhibition of both TH1 and TH2 cytokines, was additive with fluticasone propionate, and inhibited cytokine release from human lung fragments. Finally, we describe an in vivo pharmacodynamic assay that allows rapid preclinical development without animal efficacy models. PMID:23935099

Purification and sequence analysis of two rat tissue inhibitors of metalloproteinases

NASA Technical Reports Server (NTRS)

Roswit, W. T.; McCourt, D. W.; Partridge, N. C.; Jeffrey, J. J.

1992-01-01

Two protein inhibitors of metalloproteinases (TIMP) were isolated from medium conditioned by the clonal rat osteosarcoma line UMR 106-01. Initial purification of both a 30-kDa inhibitor and a 20-kDa inhibitor was accomplished using heparin-Sepharose chromatography with dextran sulfate elution followed by DEAE-Sepharose and CM-Sepharose chromatography. Purification of the 20-kDa inhibitor to homogeneity was completed with reverse-phase high-performance liquid chromatography. The 20-kDa inhibitor was identified as rat TIMP-2. The 30-kDa inhibitor, although not purified to homogeneity, was identified as rat TIMP-1. Amino terminal amino acid sequence analysis of the 30-kDa inhibitor demonstrated 86% identity to human TIMP-1 for the first 22 amino acids while the sequence of the 20-kDa inhibitor was identical to that of human TIMP-2 for the first 22 residues. Treatment with peptide:N-glycosidase F indicated that the 30-kDa rat inhibitor is glycosylated while the 20-kDa inhibitor is apparently unglycosylated. Inhibition of both rat and human interstitial collagenase by rat TIMP-2 was stoichiometric, with a 1:1 molar ratio required for complete inhibition. Exposure of UMR 106-01 cells to 10(-7) M parathyroid hormone resulted in approximately a 40% increase in total inhibitor production over basal levels.

Targeting of the MYCN Protein with Small Molecule c-MYC Inhibitors

PubMed Central

Müller, Inga; Larsson, Karin; Frenzel, Anna; Oliynyk, Ganna; Zirath, Hanna; Prochownik, Edward V.; Westwood, Nicholas J.; Henriksson, Marie Arsenian

2014-01-01

Members of the MYC family are the most frequently deregulated oncogenes in human cancer and are often correlated with aggressive disease and/or poorly differentiated tumors. Since patients with MYCN-amplified neuroblastoma have a poor prognosis, targeting MYCN using small molecule inhibitors could represent a promising therapeutic approach. We have previously demonstrated that the small molecule 10058-F4, known to bind to the c-MYC bHLHZip dimerization domain and inhibiting the c-MYC/MAX interaction, also interferes with the MYCN/MAX dimerization in vitro and imparts anti-tumorigenic effects in neuroblastoma tumor models with MYCN overexpression. Our previous work also revealed that MYCN-inhibition leads to mitochondrial dysfunction resulting in accumulation of lipid droplets in neuroblastoma cells. To expand our understanding of how small molecules interfere with MYCN, we have now analyzed the direct binding of 10058-F4, as well as three of its analogs; #474, #764 and 10058-F4(7RH), one metabolite C-m/z 232, and a structurally unrelated c-MYC inhibitor 10074-G5, to the bHLHZip domain of MYCN. We also assessed their ability to induce apoptosis, neurite outgrowth and lipid accumulation in neuroblastoma cells. Interestingly, all c-MYC binding molecules tested also bind MYCN as assayed by surface plasmon resonance. Using a proximity ligation assay, we found reduced interaction between MYCN and MAX after treatment with all molecules except for the 10058-F4 metabolite C-m/z 232 and the non-binder 10058-F4(7RH). Importantly, 10074-G5 and 10058-F4 were the most efficient in inducing neuronal differentiation and lipid accumulation in MYCN-amplified neuroblastoma cells. Together our data demonstrate MYCN-binding properties for a selection of small molecules, and provide functional information that could be of importance for future development of targeted therapies against MYCN-amplified neuroblastoma. PMID:24859015

Three-Dimensionally Engineered Normal Human Broncho-epithelial Tissue-Like Assemblies: Target Tissues for Human Respiratory Viral Infections

NASA Technical Reports Server (NTRS)

Goodwin, T. J.; McCarthy, M.; Lin, Y-H

2006-01-01

In vitro three-dimensional (3D) human broncho-epithelial (HBE) tissue-like assemblies (3D HBE TLAs) from this point forward referred to as TLAs were engineered in Rotating Wall Vessel (RWV) technology to mimic the characteristics of in vivo tissues thus providing a tool to study human respiratory viruses and host cell interactions. The TLAs were bioengineered onto collagen-coated cyclodextran microcarriers using primary human mesenchymal bronchial-tracheal cells (HBTC) as the foundation matrix and an adult human bronchial epithelial immortalized cell line (BEAS-2B) as the overlying component. The resulting TLAs share significant characteristics with in vivo human respiratory epithelium including polarization, tight junctions, desmosomes, and microvilli. The presence of tissue-like differentiation markers including villin, keratins, and specific lung epithelium markers, as well as the production of tissue mucin, further confirm these TLAs differentiated into tissues functionally similar to in vivo tissues. Increasing virus titers for human respiratory syncytial virus (wtRSVA2) and parainfluenza virus type 3 (wtPIV3 JS) and the detection of membrane bound glycoproteins over time confirm productive infections with both viruses. Therefore, TLAs mimic aspects of the human respiratory epithelium and provide a unique capability to study the interactions of respiratory viruses and their primary target tissue independent of the host's immune system.

In silico screening for inhibitors of p-glycoprotein that target the nucleotide binding domains.

PubMed

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

2014-12-01

Multidrug resistances and the failure of chemotherapies are often caused by the expression or overexpression of ATP-binding cassette transporter proteins such as the multidrug resistance protein, P-glycoprotein (P-gp). P-gp is expressed in the plasma membrane of many cell types and protects cells from accumulation of toxins. P-gp uses ATP hydrolysis to catalyze the transport of a broad range of mostly hydrophobic compounds across the plasma membrane and out of the cell. During cancer chemotherapy, the administration of therapeutics often selects for cells which overexpress P-gp, thereby creating populations of cancer cells resistant to a variety of chemically unrelated chemotherapeutics. The present study describes extremely high-throughput, massively parallel in silico ligand docking studies aimed at identifying reversible inhibitors of ATP hydrolysis that target the nucleotide-binding domains of P-gp. We used a structural model of human P-gp that we obtained from molecular dynamics experiments as the protein target for ligand docking. We employed a novel approach of subtractive docking experiments that identified ligands that bound predominantly to the nucleotide-binding domains but not the drug-binding domains of P-gp. Four compounds were found that inhibit ATP hydrolysis by P-gp. Using electron spin resonance spectroscopy, we showed that at least three of these compounds affected nucleotide binding to the transporter. These studies represent a successful proof of principle demonstrating the potential of targeted approaches for identifying specific inhibitors of P-gp. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

Targeting Mitogen-activated Protein Kinase-activated Protein Kinase 2 (MAPKAPK2, MK2): Medicinal Chemistry Efforts to Lead Small Molecule Inhibitors to Clinical Trials

PubMed Central

Fiore, Mario; Forli, Stefano; Manetti, Fabrizio

2015-01-01

The p38/MAPK-activated kinase 2 (MK2) pathway is involved in a series of pathological conditions (inflammation diseases and metastasis) and in the resistance mechanism to antitumor agents. None of the p38 inhibitors entered advanced clinical trials because of their unwanted systemic side effects. For this reason, MK2 was identified as an alternative target to block the pathway, but avoiding the side effects of p38 inhibition. However, ATP-competitive MK2 inhibitors suffered from low solubility, poor cell permeability, and scarce kinase selectivity. Fortunately, non-ATP-competitive inhibitors of MK2 have been already discovered that allowed circumventing the selectivity issue. These compounds showed the additional advantage to be effective at lower concentrations in comparison to the ATP-competitive inhibitors. Therefore, although the significant difficulties encountered during the development of these inhibitors, MK2 is still considered as an attractive target to treat inflammation and related diseases, to prevent tumor metastasis, and to increase tumor sensitivity to chemotherapeutics. PMID:26502061

Clinical Response of Carcinomas Harboring the BRD4-NUT Oncoprotein to the Targeted Bromodomain Inhibitor OTX015/MK-8628

PubMed Central

Stathis, Anastasios; Zucca, Emanuele; Bekradda, Mohamed; Gomez-Roca, Carlos; Delord, Jean-Pierre; de La Motte Rouge, Thibault; Uro-Coste, Emmanuelle; de Braud, Filippo; Pelosi, Giuseppe; French, Christopher A.

2016-01-01

The anti-neoplastic, pro-differentiative effects of bromodomain and extra-terminal (BET) bromodomain (BRD) inhibitors were initially discovered in NUT midline carcinoma (NMC), an aggressive subtype of squamous cancer driven by the BRD4-NUT fusion oncoprotein. BRD4-NUT blocks differentiation and maintains tumor growth through a potent chromatin modifying mechanism. OTX015/MK-8628, a novel oral BET inhibitor, targets BRD2/3/4/T with preclinical activity in NMC and several other tumor types, and is currently in clinical development. Antitumor activity was evaluated in four advanced stage NMC patients with confirmed BRD4-NUT fusions who were treated with 80 mg OTX015/MK-8628 once daily in a compassionate-use context. Two patients responded rapidly with tumor regression and symptomatic relief, and a third had meaningful disease stabilization with a minor metabolic response. The main side effects were mild to moderate gastrointestinal toxicity and fatigue, and reversible grade 3 thrombocytopenia. This is the first proof-of-concept evidence of clinical activity of a bromodomain inhibitor in targeting BRD4-NUT. PMID:26976114

Resistance to MEK inhibitors: should we co-target upstream?

PubMed

Poulikakos, Poulikos I; Solit, David B

2011-03-29

Aberrant activation of the ERK pathway is common in human tumors. This pathway consists of a three-tiered kinase module [comprising the kinases RAF, mitogen-activated protein kinase (MAPK) kinase (MEK), and extracellular signal-regulated kinase (ERK)] that functions as a negative feedback amplifier to confer robustness and stabilization of pathway output. Because this pathway is frequently dysregulated in human cancers, intense efforts are under way to develop selective inhibitors of the ERK pathway as anticancer drugs. Although promising results have been reported in early trials for inhibitors of RAF or MEK, resistance invariably occurs. Amplification of the upstream oncogenic driver of ERK signaling has been identified as a mechanism for MEK inhibitor resistance in cells with mutant BRAF or KRAS. Increased abundance of the oncogenic driver (either KRAS or BRAF in the appropriate cellular context) in response to prolonged drug treatment results in increased flux through the ERK pathway and restoration of ERK activity above the threshold required for cell growth. For patients with BRAF mutant tumors, the results suggest that the addition of a RAF inhibitor to a MEK inhibitor may delay or overcome drug resistance. The data thus provide a mechanistic basis for ongoing trials testing concurrent treatment with RAF and MEK inhibitors.

Discovery of a selective catalytic p300/CBP inhibitor that targets lineage-specific tumours

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

Lasko, Loren M.; Jakob, Clarissa G.; Edalji, Rohinton P.

The dynamic and reversible acetylation of proteins, catalysed by histone acetyltransferases (HATs) and histone deacetylases (HDACs), is a major epigenetic regulatory mechanism of gene transcription1 and is associated with multiple diseases. Histone deacetylase inhibitors are currently approved to treat certain cancers, but progress on the development of drug-like histone actyltransferase inhibitors has lagged behind2. The histone acetyltransferase paralogues p300 and CREB-binding protein (CBP) are key transcriptional co-activators that are essential for a multitude of cellular processes, and have also been implicated in human pathological conditions (including cancer3). Current inhibitors of the p300 and CBP histone acetyltransferase domains, including natural products4,more » bi-substrate analogues5 and the widely used small molecule C6466,7, lack potency or selectivity. Here, we describe A-485, a potent, selective and drug-like catalytic inhibitor of p300 and CBP. We present a high resolution (1.95 Å) co-crystal structure of a small molecule bound to the catalytic active site of p300 and demonstrate that A-485 competes with acetyl coenzyme A (acetyl-CoA). A-485 selectively inhibited proliferation in lineage-specific tumour types, including several haematological malignancies and androgen receptor-positive prostate cancer. A-485 inhibited the androgen receptor transcriptional program in both androgen-sensitive and castration-resistant prostate cancer and inhibited tumour growth in a castration-resistant xenograft model. These results demonstrate the feasibility of using small molecule inhibitors to selectively target the catalytic activity of histone acetyltransferases, which may provide effective treatments for transcriptional activator-driven malignancies and diseases.« less

Recombinant Buckwheat Trypsin Inhibitor Induces Mitophagy by Directly Targeting Mitochondria and Causes Mitochondrial Dysfunction in Hep G2 Cells.

PubMed

Wang, Zhuanhua; Li, Shanshan; Ren, Rong; Li, Jiao; Cui, Xiaodong

2015-09-09

Mitochondria are essential targets for cancer chemotherapy and other disease treatments. Recombinant buckwheat trypsin inhibitor (rBTI), a member of the potato type I proteinase inhibitor family, was derived from tartary buckwheat extracts. Our results showed that rBTI directly targeted mitochondria and induced mitochondrial fragmentation and mitophagy. This occurs through enhanced depolarization of the mitochondrial membrane potential, increasing reactive oxygen species (ROS) generation associated with the rise of the superoxide dismutase and catalase activity and glutathione peroxidase (GSH) content, and changes in the GSH/oxidized glutathione ratio. Mild and transient ROS induced by rBTI were shown to be important signaling molecules required to induce Hep G2 mitophagy to remove dysfunctional mitochondria. Furthermore, rBTI could directly induce mitochondrial fragmentation. It was also noted that rBTI highly increased colocalization of mitochondria in treated cells compared to nontreated cells. Tom 20, a subunit of the translocase of the mitochondrial outer membrane complex responsible for recognizing mitochondrial presequences, may be the direct target of rBTI.

Inhibitor designing, virtual screening, and docking studies for methyltransferase: A potential target against dengue virus

PubMed Central

Singh, Jagbir; Kumar, Mahesh; Mansuri, Rani; Sahoo, Ganesh Chandra; Deep, Aakash

2016-01-01

Aim: Aim of this work was to design and identify some S-adenosyl-L-homocysteine (SAH) analogs as inhibitors of S-adenosyl-L-methionine-dependent methyltransferase (MTase) protein using computational approaches. Introduction: According to the current scenario the dengue has been a global burden. The people are being killed by dengue virus in an abundant number. Despite of lot of research being going on dengue worldwide, there is no single drug which can kill its virus. This creates an urge for new drug target identification and designing. MTase has been reported as an effective target against dengue virus as it catalyzes an essential step in methylation and capping of viral RNA for viral replication. Materials and Methods: The crystal structure of MTase in complex with SAH was used for designing new analogs of SAH. SAH analogs designed were analyzed on the basis of docking, ADMET, and toxicity analysis done using Discovery Studio 3.5. Results: Seventeen analogs found noncarcinogenic, nonmutagenic, as well as good ADMET properties and good drug-like profile. Conclusion: These SAH analogs, inhibitors of MTase may act as drugs against dengue virus. Further synthesis and biological testing against dengue virus is under observation. PMID:27413346

Divergent Effects of Anandamide Transporter Inhibitors with Different Target Selectivity on Social Play Behavior in Adolescent Rats

PubMed Central

Trezza, Viviana; Vanderschuren, Louk J. M. J.

2009-01-01

The endocannabinoid system plays an important role in the modulation of affect, motivation, and emotion. Social play behavior is a natural reinforcer in adolescent rats, and we have recently shown that interacting endocannabinoid, opioid, and dopamine systems modulate social play. In the present study, we tested the hypothesis that, in contrast to administration of exogenous cannabinoid agonists, increasing local endocannabinoid signaling through anandamide transporter inhibition enhances social play. To this aim, we tested the effects of two anandamide transporter inhibitors with different target selectivity on social play behavior in adolescent rats. Interestingly, we found that the prototypical anandamide transporter inhibitor N-(4-hydroxyphenyl)-arachidonamide (AM404) reduced social play, whereas its more selective analog N-arachidonoyl-(2-methyl-4-hydroxyphenyl)amine (VDM11) enhanced it. The effects of AM404 were not mediated through its known pharmacological targets, since they were not blocked by the CB1 cannabinoid receptor antagonist N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide hydrochloride (SR141716A), the CB2 cannabinoid receptor antagonist N-(1,3,3-trimethylbicyclo(2.2.1)heptan-2-yl)-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)pyrazole-3-carboxamide (SR144528), or by the transient receptor potential vanilloid 1 receptor antagonist capsazepine. In contrast, the increase in social play induced by VDM11 was dependent on cannabinoid, opioid, and dopaminergic neurotransmission, since it was blocked by the CB1 cannabinoid receptor antagonist SR141716A, the opioid receptor antagonist naloxone, and the dopamine receptor antagonist α-flupenthixol. These findings support the notion that anandamide plays an important role in the modulation of social interaction in adolescent rats, and they suggest that selective anandamide transporter inhibitors might be useful for the treatment of social dysfunctions

Virtual Screening for the Development of Dual-Inhibitors Targeting Topoisomerase IB and Tyrosyl-DNA Phosphodiesterase 1.

PubMed

Cardamone, Francesca; Pizzi, Simone; Iacovelli, Federico; Falconi, Mattia; Desideri, Alessandro

2017-01-01

Human topoisomerase IB is an important target in cancer therapy and drugs selectively stabilizing the topoisomerase IB-DNA covalent complex are in clinical use for several cancer types. Tyrosyl- DNA phosphodiesterase 1 is involved in the DNA repair resolving the topoisomerase IB-DNA covalent complex that is extremely dangerous for the survival of the cells since it produces an irreversible DNA damage. Given the close biological relationship between these two enzymes, the development of synergistic inhibitors, called dual-inhibitors, is an important challenge in cancer therapy and computer-aided drug design may help in the identification of the best compounds. In this review, an overview of the compounds inhibiting one of the two enzymes or acting as dual inhibitors is provided. Moreover, the general procedures of the virtual screening approach, providing a description of two widely used opensource programs, namely AutoDock4 and AutoDock Vina, are described. Finally, an application of the two programs on a selected number of dual inhibitors for tyrosyl-DNA phosphodiesterase 1 and topoisomerase IB and their performance is briefly discussed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

New tools for evaluating protein tyrosine sulphation: Tyrosyl Protein Sulphotransferases (TPSTs) are novel targets for RAF protein kinase inhibitors.

PubMed

Byrne, Dominic P; Li, Yong; Ngamlert, Pawin; Ramakrishnan, Krithika; Eyers, Claire E; Wells, Carrow; Drewry, David H; Zuercher, William J; Berry, Neil G; Fernig, David G; Eyers, Patrick A

2018-06-22

Protein tyrosine sulphation is a post-translational modification best known for regulating extracellular protein-protein interactions. Tyrosine sulphation is catalysed by two Golgi-resident enzymes termed Tyrosyl Protein Sulpho Transferases (TPSTs) 1 and 2, which transfer sulphate from the co-factor PAPS (3'-phosphoadenosine 5'-phosphosulphate) to a context-dependent tyrosine in a protein substrate. A lack of quantitative tyrosine sulphation assays has hampered the development of chemical biology approaches for the identification of small molecule inhibitors of tyrosine sulphation. In this paper, we describe the development of a non-radioactive mobility-based enzymatic assay for TPST1 and TPST2, through which the tyrosine sulphation of synthetic fluorescent peptides can be rapidly quantified. We exploit ligand binding and inhibitor screens to uncover a susceptibility of TPST1 and TPST2 to different classes of small molecules, including the anti-angiogenic compound suramin and the kinase inhibitor rottlerin. By screening the Published Kinase Inhibitor Set (PKIS), we identified oxindole-based inhibitors of the Ser/Thr kinase RAF as low micromolar inhibitors of TPST1 and TPST2.  Interestingly, unrelated RAF inhibitors, exemplified by the dual BRAF/VEGFR2 inhibitor RAF265, were also TPST inhibitors in vitro We propose that target-validated protein kinase inhibitors could be repurposed, or redesigned, as more-specific TPST inhibitors to help evaluate the sulphotyrosyl proteome. Finally, we speculate that mechanistic inhibition of cellular tyrosine sulphation might be relevant to some of the phenotypes observed in cells exposed to anionic TPST ligands and RAF protein kinase inhibitors. ©2018 The Author(s).

A human fatty acid synthase inhibitor binds β-ketoacyl reductase in the keto-substrate site.

PubMed

Hardwicke, Mary Ann; Rendina, Alan R; Williams, Shawn P; Moore, Michael L; Wang, Liping; Krueger, Julie A; Plant, Ramona N; Totoritis, Rachel D; Zhang, Guofeng; Briand, Jacques; Burkhart, William A; Brown, Kristin K; Parrish, Cynthia A

2014-09-01

Human fatty acid synthase (hFAS) is a complex, multifunctional enzyme that is solely responsible for the de novo synthesis of long chain fatty acids. hFAS is highly expressed in a number of cancers, with low expression observed in most normal tissues. Although normal tissues tend to obtain fatty acids from the diet, tumor tissues rely on de novo fatty acid synthesis, making hFAS an attractive metabolic target for the treatment of cancer. We describe here the identification of GSK2194069, a potent and specific inhibitor of the β-ketoacyl reductase (KR) activity of hFAS; the characterization of its enzymatic and cellular mechanism of action; and its inhibition of human tumor cell growth. We also present the design of a new protein construct suitable for crystallography, which resulted in what is to our knowledge the first co-crystal structure of the human KR domain and includes a bound inhibitor.

A Phenotypic Based Target Screening Approach Delivers New Antitubercular CTP Synthetase Inhibitors.

PubMed

Esposito, Marta; Szadocka, Sára; Degiacomi, Giulia; Orena, Beatrice S; Mori, Giorgia; Piano, Valentina; Boldrin, Francesca; Zemanová, Júlia; Huszár, Stanislav; Barros, David; Ekins, Sean; Lelièvre, Joel; Manganelli, Riccardo; Mattevi, Andrea; Pasca, Maria Rosalia; Riccardi, Giovanna; Ballell, Lluis; Mikušová, Katarína; Chiarelli, Laurent R

2017-06-09

Despite its great potential, the target-based approach has been mostly unsuccessful in tuberculosis drug discovery, while whole cell phenotypic screening has delivered several active compounds. However, for many of these hits, the cellular target has not yet been identified, thus preventing further target-based optimization of the compounds. In this context, the newly validated drug target CTP synthetase PyrG was exploited to assess a target-based approach of already known, but untargeted, antimycobacterial compounds. To this purpose the publically available GlaxoSmithKline antimycobacterial compound set was assayed, uncovering a series of 4-(pyridin-2-yl)thiazole derivatives which efficiently inhibit the Mycobacterium tuberculosis PyrG enzyme activity, one of them showing low activity against the human CTP synthetase. The three best compounds were ATP binding site competitive inhibitors, with K i values ranging from 3 to 20 μM, but did not show any activity against a small panel of different prokaryotic and eukaryotic kinases, thus demonstrating specificity for the CTP synthetases. Metabolic labeling experiments demonstrated that the compounds directly interfere not only with CTP biosynthesis, but also with other CTP dependent biochemical pathways, such as lipid biosynthesis. Moreover, using a M. tuberculosis pyrG conditional knock-down strain, it was shown that the activity of two compounds is dependent on the intracellular concentration of the CTP synthetase. All these results strongly suggest a role of PyrG as a target of these compounds, thus strengthening the value of this kind of approach for the identification of new scaffolds for drug development.

Targeting FASN in Breast Cancer and the Discovery of Promising Inhibitors from Natural Products Derived from Traditional Chinese Medicine

PubMed Central

Cheng, Chien-shan; Wang, Zhiyu; Chen, Jianping

2014-01-01

Molecular targeted therapy has been developed for cancer chemoprevention and treatment. Cancer cells process a fundamental change in its bioenergetic metabolism from normal cells on an altered lipid metabolism, also known as the de novo fatty acid synthesis, for sustaining their high proliferation rates. Fatty acid synthesis is now associated with clinically aggressive tumor behavior and tumor cell growth and has become a novel target pathway for chemotherapy development. Although the underlying mechanisms of the altered de novo fatty acid synthesis still remains unclear, recent progress has shown that by targeting Fatty acid synthase (FASN), a key enzyme that catalyzes the synthesis of endogenous long chain fatty acid could be a critical target for drug discovery. However, relatively few FASN inhibitors have been discovered. With the long history of clinical practices and numerous histological case study reports, traditional Chinese medicine enjoys an important role in seeking bioactive anticancer natural compounds. Herein, we will give an overall picture of the current progress of molecular targeted therapy in cancer fatty acid synthesis, describe the advances in the research on natural products-derived FASN inhibitors and their potential for enhancing our understanding of fatty acids in tumor biology, and may provide new therapeutic moieties for breast cancer patient care. PMID:24778702

Targeting IκB kinase β/NF-κB signaling in human prostate cancer by a novel IκB kinase β inhibitor CmpdA

PubMed Central

Zhang, Yanting; Lapidus, Rena G.; Liu, Peiyan; Choi, Eun Yong; Adediran, Samusi; Hussain, Arif; Wang, Xinghuan; Liu, Xuefeng; Dan, Han C.

2016-01-01

NF-κB plays an important role in many types of cancer, including prostate cancer (PCa), but the role of the upstream kinase of NF-κB, IKKβ, in PCa has not been fully documented, nor are there any effective IKKβ inhibitors used in clinical settings. Here, we have shown that IKKβ activity is mediated by multiple kinases including IKKα in human PCa cell lines that express activated IKKβ. Immunohistochemical analysis (IHC) of human PCa tissue microarrays (TMA) demonstrates that phosphorylation of IKKα/β within its activation loop gradually increases in low to higher stage tumors as compared to normal tissue. The expression of cell proliferation and survival markers (Ki67, Survivin), epithelial-to-mesenchymal transition (EMT) markers (Slug, Snail), as well as cancer stem cell (CSC) related transcription factors (Nanog, Sox2, Oct-4), also increase in parallel among the respective TMA samples analyzed. IKKβ, but not NF-κB, is found to regulate Nanog, which, in turn, modulates the levels of Oct4, Sox2, Snail and Slug, indicating an essential role of IKKβ in regulating cancer stem cells and EMT. The novel IKKβ inhibitor CmpdA inhibits constitutively activated IKKβ/NF-κB signaling, leading to induction of apoptosis and inhibition of proliferation, migration and stemness in these cells. CmpdA also significantly inhibits tumor growth in xenografts without causing apparent in vivo toxicity. Furthermore, CmpdA and docetaxel act synergistically to inhibit proliferation of PCa cells. These results indicate that IKKβ plays a pivotal role in PCa, and targeting IKKβ, including in combination with docetaxel, may be a potentially useful strategy for treating advanced PCa. PMID:27196761

Shared target antigens on cancer cells and tissue stem cells: go or no-go for CAR T cells?

PubMed

Hombach, Andreas A; Abken, Hinrich

2017-02-01

Adoptive therapy with chimeric antigen receptor (CAR) T cells redirected towards CD19 produces remissions of B cell malignancies, however, it also eradicates healthy B cells sharing the target antigen. Such 'on-target off-tumor' toxicity raises serious safety concerns when the target antigen is also expressed by tissue stem cells, with the risk of lasting tissue destruction. Areas covered: We discuss CAR T cell targeting of activation antigens versus lineage associated antigens on the basis of recent experimental and animal data and the literature in the field. Expert commentary: Targeting an activation associated antigen which is transiently expressed by stem cells seems to be safe, like CAR T cells targeting CD30 spare CD30 + hematopoietic stem and progenitor cells while eliminating CD30 + lymphoma cells, whereas targeting lineage associated antigens which increase in expression during cell maturation, like folate receptor-β and CD123, is of risk to destruct tissue stem cells.

Newer treatments of psoriasis regarding IL-23 inhibitors, phosphodiesterase 4 inhibitors, and Janus kinase inhibitors.

PubMed

Wcisło-Dziadecka, Dominika; Zbiciak-Nylec, Martyna; Brzezińska-Wcisło, Ligia; Bebenek, Katarzyna; Kaźmierczak, Agata

2017-11-01

The rapid progress of genetic engineering furthermore opens up new prospects in the therapy of this difficult-to-treat disease. IL-23 inhibitors, phosphodiesterase 4 (PDE4) inhibitors, and Janus kinase (JAK) inhibitors are currently encouraging further research. Two drugs which are IL-23 inhibitors are now in phase III of clinical trials. The aim of the action of both drugs is selective IL-23 inhibition by targeting the p19 subunit. Guselkumab is a fully human monoclonal antibody. Tildrakizumab is a humanized monoclonal antibody, which also belongs to IgG class and is targeted to subunit p19 of interleukin 23 (IL-23). Phosphodiesterase inhibitors exert an anti-inflammatory action and their most common group is the PDE4 family. PDE4 inhibits cAMP, which reduces the inflammatory response of the pathway of Th helper lymphocytes, Th17, and type 1 interferon which modulates the production of anti-inflammatory cytokines such as IL-10 interleukins. The Janus kinase (JAK) signaling pathway plays an important role in the immunopathogenesis of psoriasis. Tofacitinib suppresses the expression of IL-23, IL-17A, IL-17F, and IL-22 receptors during the stimulation of lymphocytes. Ruxolitinib is a selective inhibitor of JAK1 and JAK2 kinases and the JAK-STAT signaling pathway. This article is a review of the aforementioned drugs as described in the latest available literature. © 2017 Wiley Periodicals, Inc.

Targeting DDX3 with a small molecule inhibitor for lung cancer therapy.

PubMed

Bol, Guus M; Vesuna, Farhad; Xie, Min; Zeng, Jing; Aziz, Khaled; Gandhi, Nishant; Levine, Anne; Irving, Ashley; Korz, Dorian; Tantravedi, Saritha; Heerma van Voss, Marise R; Gabrielson, Kathleen; Bordt, Evan A; Polster, Brian M; Cope, Leslie; van der Groep, Petra; Kondaskar, Atul; Rudek, Michelle A; Hosmane, Ramachandra S; van der Wall, Elsken; van Diest, Paul J; Tran, Phuoc T; Raman, Venu

2015-05-01

Lung cancer is the most common malignancy worldwide and is a focus for developing targeted therapies due to its refractory nature to current treatment. We identified a RNA helicase, DDX3, which is overexpressed in many cancer types including lung cancer and is associated with lower survival in lung cancer patients. We designed a first-in-class small molecule inhibitor, RK-33, which binds to DDX3 and abrogates its activity. Inhibition of DDX3 by RK-33 caused G1 cell cycle arrest, induced apoptosis, and promoted radiation sensitization in DDX3-overexpressing cells. Importantly, RK-33 in combination with radiation induced tumor regression in multiple mouse models of lung cancer. Mechanistically, loss of DDX3 function either by shRNA or by RK-33 impaired Wnt signaling through disruption of the DDX3-β-catenin axis and inhibited non-homologous end joining-the major DNA repair pathway in mammalian somatic cells. Overall, inhibition of DDX3 by RK-33 promotes tumor regression, thus providing a compelling argument to develop DDX3 inhibitors for lung cancer therapy. © 2015 The Authors. Published under the terms of the CC BY 4.0 license.

Risk evaluation and mitigation strategies: a focus on the mammalian target of rapamycin inhibitors.

PubMed

Gabardi, Steven

2013-03-01

To review the history of risk evaluation and mitigation strategies (REMS) with the mammalian target of rapamycin (mToR) inhibitors, evaluate their required REMS elements, and delineate the reasons for them being released from their REMS requirements. Articles were identified through a literature search of MEDLINE and EMBASE (January 2007-July 2012) using the search terms: risk evaluation and mitigation strategies, REMS, everolimus, sirolimus and organ transplant (individual organs also were searched). Information from the Federal Register, the Food and Drug Administration, and the manufacturers of the mToR inhibitors was also evaluated. REMS are strategies implemented to manage known or potential risks associated with medications and to ensure ongoing pharmacovigilance throughout the life of a pharmaceutical product. The mToR inhibitors have been associated with several potential risks, including proteinuria, graft thrombosis, and wound-healing complications. The Food and Drug Administration approved REMS programs for both sirolimus and everolimus. The manufacturers of both medications complied with the components of their approved REMS, but after less than 2 years, both medications have been relieved of their REMS obligations. The only element of the sirolimus REMS was a medication guide, whereas the everolimus REMS consisted of a medication guide and a communication plan. The sirolimus REMS was implemented more than 10 years after its initial approval by the Food and Drug Administration, but was released from its REMS requirement within 7 months of its implementation. The everolimus REMS was instituted upon initial approval and was removed approximately 2 years later. Both medications' REMS were always intended to educate health care providers and patients about the potential risks associated with this transplant immunosuppressant. Transplant practitioners should be familiar with the mToR inhibitors' associated risks and properly educate patients regarding the

Structures of Cryptococcus neoformans Protein Farnesyltransferase Reveal Strategies for Developing Inhibitors That Target Fungal Pathogens

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

Hast, Michael A.; Nichols, Connie B.; Armstrong, Stephanie M.

Cryptococcus neoformans is a fungal pathogen that causes life-threatening infections in immunocompromised individuals, including AIDS patients and transplant recipients. Few antifungals can treat C. neoformans infections, and drug resistance is increasing. Protein farnesyltransferase (FTase) catalyzes post-translational lipidation of key signal transduction proteins and is essential in C. neoformans. We present a multidisciplinary study validating C. neoformans FTase (CnFTase) as a drug target, showing that several anticancer FTase inhibitors with disparate scaffolds can inhibit C. neoformans and suggesting structure-based strategies for further optimization of these leads. Structural studies are an essential element for species-specific inhibitor development strategies by revealing similarities andmore » differences between pathogen and host orthologs that can be exploited. We, therefore, present eight crystal structures of CnFTase that define the enzymatic reaction cycle, basis of ligand selection, and structurally divergent regions of the active site. Crystal structures of clinically important anticancer FTase inhibitors in complex with CnFTase reveal opportunities for optimization of selectivity for the fungal enzyme by modifying functional groups that interact with structurally diverse regions. A substrate-induced conformational change in CnFTase is observed as part of the reaction cycle, a feature that is mechanistically distinct from human FTase. Our combined structural and functional studies provide a framework for developing FTase inhibitors to treat invasive fungal infections.« less

Characterization of a Novel Class of Polyphenolic Inhibitors of Plasminogen Activator Inhibitor-1*

PubMed Central

Cale, Jacqueline M.; Li, Shih-Hon; Warnock, Mark; Su, Enming J.; North, Paul R.; Sanders, Karen L.; Puscau, Maria M.; Emal, Cory D.; Lawrence, Daniel A.

2010-01-01

Plasminogen activator inhibitor type 1, (PAI-1) the primary inhibitor of the tissue-type (tPA) and urokinase-type (uPA) plasminogen activators, has been implicated in a wide range of pathological processes, making it an attractive target for pharmacologic inhibition. Currently available small-molecule inhibitors of PAI-1 bind with relatively low affinity and do not inactivate PAI-1 in the presence of its cofactor, vitronectin. To search for novel PAI-1 inhibitors with improved potencies and new mechanisms of action, we screened a library selected to provide a range of biological activities and structural diversity. Five potential PAI-1 inhibitors were identified, and all were polyphenolic compounds including two related, naturally occurring plant polyphenols that were structurally similar to compounds previously shown to provide cardiovascular benefit in vivo. Unique second generation compounds were synthesized and characterized, and several showed IC50 values for PAI-1 between 10 and 200 nm. This represents an enhanced potency of 10–1000-fold over previously reported PAI-1 inactivators. Inhibition of PAI-1 by these compounds was reversible, and their primary mechanism of action was to block the initial association of PAI-1 with a protease. Consistent with this mechanism and in contrast to previously described PAI-1 inactivators, these compounds inactivate PAI-1 in the presence of vitronectin. Two of the compounds showed efficacy in ex vivo plasma and one blocked PAI-1 activity in vivo in mice. These data describe a novel family of high affinity PAI-1-inactivating compounds with improved characteristics and in vivo efficacy, and suggest that the known cardiovascular benefits of dietary polyphenols may derive in part from their inactivation of PAI-1. PMID:20061381

Roles of histone deacetylases in epigenetic regulation: emerging paradigms from studies with inhibitors.

PubMed

Delcuve, Geneviève P; Khan, Dilshad H; Davie, James R

2012-03-12

The zinc-dependent mammalian histone deacetylase (HDAC) family comprises 11 enzymes, which have specific and critical functions in development and tissue homeostasis. Mounting evidence points to a link between misregulated HDAC activity and many oncologic and nononcologic diseases. Thus the development of HDAC inhibitors for therapeutic treatment garners a lot of interest from academic researchers and biotechnology entrepreneurs. Numerous studies of HDAC inhibitor specificities and molecular mechanisms of action are ongoing. In one of these studies, mass spectrometry was used to characterize the affinities and selectivities of HDAC inhibitors toward native HDAC multiprotein complexes in cell extracts. Such a novel approach reproduces in vivo molecular interactions more accurately than standard studies using purified proteins or protein domains as targets and could be very useful in the isolation of inhibitors with superior clinical efficacy and decreased toxicity compared to the ones presently tested or approved. HDAC inhibitor induced-transcriptional reprogramming, believed to contribute largely to their therapeutic benefits, is achieved through various and complex mechanisms not fully understood, including histone deacetylation, transcription factor or regulator (including HDAC1) deacetylation followed by chromatin remodeling and positive or negative outcome regarding transcription initiation. Although only a very low percentage of protein-coding genes are affected by the action of HDAC inhibitors, about 40% of noncoding microRNAs are upregulated or downregulated. Moreover, a whole new world of long noncoding RNAs is emerging, revealing a new class of potential targets for HDAC inhibition. HDAC inhibitors might also regulate transcription elongation and have been shown to impinge on alternative splicing.

Management of pulmonary toxicity associated with targeted anticancer therapies.

PubMed

Teuwen, Laure-Anne; Van den Mooter, Tom; Dirix, Luc

2015-01-01

Targeted anticancer therapies act by interfering with defined molecular entities and/or biologic pathways. Because of their more specific mechanism of action, adverse events (AEs) on healthy tissues are intended to be minimal, resulting in a different toxicity profile from that observed with conventional cytotoxic chemotherapy. Pulmonary AEs are rare but potentially life-threatening and it is, therefore, critical to recognize early on and manage appropriately. In this review, we aim to offer an overview of both more frequent and rare pulmonary AEs caused by targeted anticancer therapies and discuss possible treatment algorithms. Anti-vascular endothelial growth factor, anti-human epidermal growth factor receptor and anti-CD20 therapy will be reviewed, as well as immune checkpoint inhibitors, anaplastic lymphoma kinase inhibitors and mammalian target of rapamycin inhibitors. Novel agents used in the treatment of cancer have specific side-effects, the result of allergic reactions, on-target and off-target effects. Clinical syndromes associated with pulmonary toxicity vary from bronchospasms, hypersensitivity reactions, pneumonitis, acute respiratory distress, lung bleeding, pleural effusion to pneumothorax. Knowledge of risk factors, a high index of suspicion and a complete diagnostic work-up are essential for limiting the risk of these events becoming life threatening. The development of treatment algorithms is extremely helpful in managing these events. It is probable that these toxicities will be even more frequent with the introduction of combination therapies with the obvious challenge of discerning the responsible agent.

Target-induced formation of neuraminidase inhibitors from in vitro virtual combinatorial libraries

PubMed Central

Hochgürtel, Matthias; Kroth, Heiko; Piecha, Dorothea; Hofmann, Michael W.; Nicolau, Claude; Krause, Sonja; Schaaf, Otmar; Sonnenmoser, Gabriele; Eliseev, Alexey V.

2002-01-01

Neuraminidase, a key enzyme responsible for influenza virus propagation, has been used as a template for selective synthesis of small subsets of its own inhibitors from theoretically highly diverse dynamic combinatorial libraries. We show that the library building blocks, aldehydes and amines, form significant amounts of the library components resulting from their coupling by reductive amination only in the presence of the enzyme. The target amplifies the best hits at least 120-fold. The dynamic libraries synthesized and screened in such an in vitro virtual mode form the components that possess high inhibitory activity, as confirmed by enzyme assays with independently synthesized individual compounds. PMID:11891312

Cell-Specific Establishment of Poliovirus Resistance to an Inhibitor Targeting a Cellular Protein

PubMed Central

Viktorova, Ekaterina G.; Nchoutmboube, Jules; Ford-Siltz, Lauren A.

2015-01-01

ABSTRACT It is hypothesized that targeting stable cellular factors involved in viral replication instead of virus-specific proteins may raise the barrier for development of resistant mutants, which is especially important for highly adaptable small (+)RNA viruses. However, contrary to this assumption, the accumulated evidence shows that these viruses easily generate mutants resistant to the inhibitors of cellular proteins at least in some systems. We investigated here the development of poliovirus resistance to brefeldin A (BFA), an inhibitor of the cellular protein GBF1, a guanine nucleotide exchange factor for the small cellular GTPase Arf1. We found that while resistant viruses can be easily selected in HeLa cells, they do not emerge in Vero cells, in spite that in the absence of the drug both cultures support robust virus replication. Our data show that the viral replication is much more resilient to BFA than functioning of the cellular secretory pathway, suggesting that the role of GBF1 in the viral replication is independent of its Arf activating function. We demonstrate that the level of recruitment of GBF1 to the replication complexes limits the establishment and expression of a BFA resistance phenotype in both HeLa and Vero cells. Moreover, the BFA resistance phenotype of poliovirus mutants is also cell type dependent in different cells of human origin and results in a fitness loss in the form of reduced efficiency of RNA replication in the absence of the drug. Thus, a rational approach to the development of host-targeting antivirals may overcome the superior adaptability of (+)RNA viruses. IMPORTANCE Compared to the number of viral diseases, the number of available vaccines is miniscule. For some viruses vaccine development has not been successful after multiple attempts, and for many others vaccination is not a viable option. Antiviral drugs are needed for clinical practice and public health emergencies. However, viruses are highly adaptable and can

Epithelioid Sarcoma: Opportunities for Biology-Driven Targeted Therapy.

PubMed

Noujaim, Jonathan; Thway, Khin; Bajwa, Zia; Bajwa, Ayeza; Maki, Robert G; Jones, Robin L; Keller, Charles

2015-01-01

Epithelioid sarcoma (ES) is a soft tissue sarcoma of children and young adults for which the preferred treatment for localized disease is wide surgical resection. Medical management is to a great extent undefined, and therefore for patients with regional and distal metastases, the development of targeted therapies is greatly desired. In this review, we will summarize clinically relevant biomarkers (e.g., SMARCB1, CA125, dysadherin, and others) with respect to targeted therapeutic opportunities. We will also examine the role of EGFR, mTOR, and polykinase inhibitors (e.g., sunitinib) in the management of local and disseminated disease. Toward building a consortium of pharmaceutical, academic, and non-profit collaborators, we will discuss the state of resources for investigating ES with respect to cell line resources, tissue banks, and registries so that a roadmap can be developed toward effective biology-driven therapies.

Development of chemical inhibitors of the SARS coronavirus: viral helicase as a potential target.

PubMed

Keum, Young-Sam; Jeong, Yong-Joo

2012-11-15

Severe acute respiratory syndrome (SARS) was the first pandemic in the 21st century to claim more than 700 lives worldwide. However, effective anti-SARS vaccines or medications are currently unavailable despite being desperately needed to adequately prepare for a possible SARS outbreak. SARS is caused by a novel coronavirus, and one of its components, a viral helicase, is emerging as a promising target for the development of chemical SARS inhibitors. In the following review, we describe the characterization, family classification, and kinetic movement mechanisms of the SARS coronavirus (SCV) helicase-nsP13. We also discuss the recent progress in the identification of novel chemical inhibitors of nsP13 in the context of our recent discovery of the strong inhibition of the SARS helicase by natural flavonoids, myricetin and scutellarein. These compounds will serve as important resources for the future development of anti-SARS medications. Copyright © 2012 Elsevier Inc. All rights reserved.

Novel Kinase Inhibitors Targeting the PH Domain of AKT for Preventing and Treating Cancer | NCI Technology Transfer Center | TTC

Cancer.gov

The National Cancer Institute's Medical Oncology Branch is seeking statements of capability or interest from parties interested in licensing and co-development collaborative research to further develop, evaluate, or commercialize novel kinase inhibitors targeting the PH domain of AKT.

Fusion proteins comprising annexin V and Kunitz protease inhibitors are highly potent thrombogenic site-directed anticoagulants

PubMed Central

Chen, Hsiu-Hui; Vicente, Cristina P.; He, Li; Tollefsen, Douglas M.; Wun, Tze-Chein

2005-01-01

The anionic phospholipid, phosphatidyl-l-serine (PS), is sequestered in the inner layer of the plasma membrane in normal cells. Upon injury, activation, and apoptosis, PS becomes exposed on the surfaces of cells and sheds microparticles, which are procoagulant. Coagulation is initiated by formation of a tissue factor/factor VIIa complex on PS-exposed membranes and propagated through the assembly of intrinsic tenase (factor VIIIa/factor IXa), prothrombinase (factor Va/factor Xa), and factor XIa complexes on PS-exposed activated platelets. We constructed a novel series of recombinant anticoagulant fusion proteins by linking annexin V (ANV), a PS-binding protein, to the Kunitz-type protease inhibitor (KPI) domain of tick anticoagulant protein, an aprotinin mutant (6L15), amyloid β-protein precursor, or tissue factor pathway inhibitor. The resulting ANV-KPI fusion proteins were 6- to 86-fold more active than recombinant tissue factor pathway inhibitor and tick anticoagulant protein in an in vitro tissue factor–initiated clotting assay. The in vivo antithrombotic activities of the most active constructs were 3- to 10-fold higher than that of ANV in a mouse arterial thrombosis model. ANV-KPI fusion proteins represent a new class of anticoagulants that specifically target the anionic membrane-associated coagulation enzyme complexes present at sites of thrombogenesis and are potentially useful as antithrombotic agents. PMID:15677561

Induction of Tissue Factor Pathway Inhibitor 2 by hCG Regulates Periovulatory Gene Expression and Plasmin Activity

PubMed Central

Puttabyatappa, Muraly; Al-Alem, Linah F.; Zakerkish, Farnosh; Rosewell, Katherine L.; Brännström, Mats

2017-01-01

Increased proteolytic activity is a key event that aids in breakdown of the follicular wall to permit oocyte release. How the protease activity is regulated is still unknown. We hypothesize that tissue factor pathway inhibitor 2 (TFPI2), a Kunitz-type serine protease inhibitor, plays a role in regulating periovulatory proteolytic activity as in other tissues. TFPI2 is secreted into the extracellular matrix (ECM) where it is postulated to regulate physiological ECM remodeling. The expression profile of TFPI2 during the periovulatory period was assessed utilizing a well-characterized human menstrual cycle model and a gonadotropin-primed rat model. Administration of an ovulatory dose of human chorionic gonadotropin (hCG) increased TFPI2 expression dramatically in human and rat granulosa and theca cells. This increase in Tfpi2 expression in rat granulosa cells required hCG-mediated epidermal growth factor, protein kinase A, mitogen-activated protein kinase (MAPK) 1/2, p38 MAPK and protease activated receptor 1-dependent cell signaling. A small interferingRNA-mediated knockdown of TFPI2 in rat granulosa cells resulted in increased plasmin activity in the granulosa cell conditioned media. Knockdown of TFPI2 also reduced expression of multiple genes including interleukin 6 (Il6) and amphiregulin (Areg). Overexpression of TFPI2 using an adenoviral vector partially restored the expression of Il6 and Areg in TFPI2 siRNA treated rat granulosa cells. These data support the hypothesis that TFPI2 is important for moderating plasmin activity and regulating granulosa cell gene expression during the periovulatory period. We, therefore, propose that through these actions, TFPI2 aids in the tissue remodeling taking place during follicular rupture and corpus luteum formation. PMID:27813674

MicroRNA-143-3p inhibits hyperplastic scar formation by targeting connective tissue growth factor CTGF/CCN2 via the Akt/mTOR pathway.

PubMed

Mu, Shengzhi; Kang, Bei; Zeng, Weihui; Sun, Yaowen; Yang, Fan

2016-05-01

Post-traumatic hypertrophic scar (HS) is a fibrotic disease with excessive extracellular matrix (ECM) production, which is a response to tissue injury by fibroblasts. Although emerging evidence has indicated that miRNA contributes to hypertrophic scarring, the role of miRNA in HS formation remains unclear. In this study, we found that miR-143-3p was markedly downregulated in HS tissues and fibroblasts (HSFs) using qRT-PCR. The expression of connective tissue growth factor (CTGF/CCN2) was upregulated both in HS tissues and HSFs, which is proposed to play a key role in ECM deposition in HS. The protein expression of collagen I (Col I), collagen III (Col III), and α-smooth muscle actin (α-SMA) was obviously inhibited after treatment with miR-143-3p in HSFs. The CCK-8 assay showed that miR-143-3p transfection reduced the proliferation ability of HSFs, and flow cytometry showed that either early or late apoptosis of HSFs was upregulated by miR-143-3p. In addition, the activity of caspase 3 and caspase 9 was increased after miR-143-3p transfection. On the contrary, the miR-143-3p inhibitor was demonstrated to increase cell proliferation and inhibit apoptosis of HSFs. Moreover, miR-143-3p targeted the 3'-UTR of CTGF and caused a significant decrease of CTGF. Western blot demonstrated that Akt/mTOR phosphorylation and the expression of CTGF, Col I, Col III, and α-SMA were inhibited by miR-143-3p, but increased by CTGF overexpression. In conclusion, we found that miR-143-3p inhibits hypertrophic scarring by regulating the proliferation and apoptosis of human HSFs, inhibiting ECM production-associated protein expression by targeting CTGF, and restraining the Akt/mTOR pathway.

Targeting the proteasome pathway.

PubMed

Tsukamoto, Sachiko; Yokosawa, Hideyoshi

2009-05-01

The ubiquitin-proteasome pathway functions as a main pathway in intracellular protein degradation and plays a vital role in almost all cellular events. Various inhibitors of this pathway have been developed for research purposes. The recent approval of bortezomib (PS-341, Velcade, a proteasome inhibitor, for the treatment of multiple myeloma has opened the way to the discovery of drugs targeting the proteasome and other components of the ubiquitin-proteasome pathway. We review the current understanding of the ubiquitin-proteasome pathway and inhibitors targeting this pathway, including proteasome inhibitors, as candidate drugs for chemical therapy. Preclinical and clinical data for inhibitors of the proteasome and the ubiquitin-proteasome pathway are discussed. The proteasome and other members in the ubiquitin-proteasome pathway have emerged as novel therapeutic targets.

A portrait of tissue phosphoprotein stability in the clinical tissue procurement process.

PubMed

Espina, Virginia; Edmiston, Kirsten H; Heiby, Michael; Pierobon, Mariaelena; Sciro, Manuela; Merritt, Barbara; Banks, Stacey; Deng, Jianghong; VanMeter, Amy J; Geho, David H; Pastore, Lucia; Sennesh, Joel; Petricoin, Emanuel F; Liotta, Lance A

2008-10-01

Little is known about the preanalytical fluctuations of phosphoproteins during tissue procurement for molecular profiling. This information is crucial to establish guidelines for the reliable measurement of these analytes. To develop phosphoprotein profiles of tissue subjected to the trauma of excision, we measured the fidelity of 53 signal pathway phosphoproteins over time in tissue specimens procured in a community clinical practice. This information provides strategies for potential surrogate markers of stability and the design of phosphoprotein preservative/fixation solutions. Eleven different specimen collection time course experiments revealed augmentation (+/-20% from the time 0 sample) of signal pathway phosphoprotein levels as well as decreases over time independent of tissue type, post-translational modification, and protein subcellular location (tissues included breast, colon, lung, ovary, and uterus (endometrium/myometrium) and metastatic melanoma). Comparison across tissue specimens showed an >20% decrease of protein kinase B (AKT) Ser-473 (p < 0.002) and myristoylated alanine-rich C-kinase substrate protein Ser-152/156 (p < 0.0001) within the first 90-min postexcision. Proteins in apoptotic (cleaved caspase-3 Asp-175 (p < 0.001)), proliferation/survival/hypoxia (IRS-1 Ser-612 (p < 0.0003), AMP-activated protein kinase beta Ser-108 (p < 0.005), ERK Thr-202/Tyr-204 (p < 0.003), and GSK3alphabeta Ser-21/9 (p < 0.01)), and transcription factor pathways (STAT1 Tyr-701 (p < 0.005) and cAMP response element-binding protein Ser-133 (p < 0.01)) showed >20% increases within 90-min postprocurement. Endothelial nitric-oxide synthase Ser-1177 did not change over the time period evaluated with breast or leiomyoma tissue. Treatment with phosphatase or kinase inhibitors alone revealed that tissue kinase pathways are active ex vivo. Combinations of kinase and phosphatase inhibitors appeared to stabilize proteins that exhibited increases in the presence of phosphatase

Neratinib, A Novel HER2-Targeted Tyrosine Kinase Inhibitor.

PubMed

Tiwari, Shruti Rakesh; Mishra, Prasun; Abraham, Jame

2016-10-01

HER2 gene amplification and receptor overexpression is identified in 20% to 25% of human breast cancers. Use of targeted therapy for HER2-amplified breast cancer has led to improvements in disease-free and overall survival in this subset of patients. Neratinib is an oral pan HER inhibitor, that irreversibly inhibits the tyrosine kinase activity of epidermal growth factor receptor (EGFR or HER1), HER2, and HER4, which leads to reduced phosphorylation and activation of downstream signaling pathways. Neratinib is currently being tested in a number of clinical trials for its safety and efficacy in lung cancer, and colorectal, bladder, and breast cancers. In this review we discuss the available phase I, II, and III data for use of neratinib in the metastatic, adjuvant, neoadjuvant, and extended adjuvant settings along with the ongoing clinical trials of neratinib in breast cancer. We also elaborate on the side effect profile of this relatively new drug and provide guidelines for its use in clinical practice. Copyright © 2016 Elsevier Inc. All rights reserved.

Linifanib--a multi-targeted receptor tyrosine kinase inhibitor and a low molecular weight gelator.

PubMed

Marlow, Maria; Al-Ameedee, Mohammed; Smith, Thomas; Wheeler, Simon; Stocks, Michael J

2015-04-14

In this study we demonstrate that linifanib, a multi-targeted receptor tyrosine kinase inhibitor, with a key urea containing pharmacophore, self-assembles into a hydrogel in the presence of low amounts of solvent. We demonstrate the role of the urea functional group and that of fluorine substitution on the adjacent aromatic ring in promoting self-assembly. We have also shown that linifanib has superior mechanical strength to two structurally related analogues and hence increased potential for localisation at an injection site for drug delivery applications.

Targeted microbubbles with ultrasound irradiation and PD-1 inhibitor to increase antitumor activity in B-cell lymphoma.

PubMed

Zheng, Shiya; Song, Dan; Jin, Xiaoxiao; Zhang, Haijun; Aldarouish, Mohanad; Chen, Yan; Wang, Cailian

2018-02-01

Severe cardiac toxicity of doxorubicin and an immunosuppressive tumor micro-environment become main obstacles for the effective treatment of B-cell lymphoma. In this research, rituximab-conjugated and doxorubicin-loaded microbubbles (RDMs) were designed for exploring a combination approach of targeted microbubbles with ultrasound (US) irradiation and PD-1 inhibitor to overcome obstacles mentioned above. In vivo studies were performed on SU-DHL-4 cell-grafted mice and ex vivo studies were performed on CD20 + human SU-DHL-4 cells and human T cells. A greater therapeutic effect and higher expression of PD-L1 protein expression were obtained with RDMs with US irradiation in vivo. A significant inhibitory effect on SU-DHL-4 B-cell lymphoma cells was observed after treated by RDMs with US irradiation and PD-1 inhibitor ex vivo. Combination of RDMs with US irradiation and PD-1 inhibitor could be a promising therapeutic strategy for B-cell lymphoma.

Mammalian target of rapamycin inhibitors, temsirolimus and torin 1, attenuate stemness-associated properties and expression of mesenchymal markers promoted by phorbol-myristate-acetate and oncostatin-M in glioblastoma cells.

PubMed

Chandrika, Goparaju; Natesh, Kumar; Ranade, Deepak; Chugh, Ashish; Shastry, Padma

2017-03-01

The phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin signaling pathway is crucial for tumor survival, proliferation, and progression, making it an attractive target for therapeutic intervention. In glioblastoma, activated mammalian target of rapamycin promotes invasive phenotype and correlates with poor patient survival. A wide range of mammalian target of rapamycin inhibitors are currently being evaluated for cytotoxicity and anti-proliferative activity in various tumor types but are not explored sufficiently for controlling tumor invasion and recurrence. We recently reported that mammalian target of rapamycin inhibitors-rapamycin, temsirolimus, torin 1, and PP242-suppressed invasion and migration promoted by tumor necrosis factor-alpha and phorbol-myristate-acetate in glioblastoma cells. As aggressive invasion and migration of tumors are associated with mesenchymal and stem-like cell properties, this study aimed to examine the effect of mammalian target of rapamycin inhibitors on these features in glioblastoma cells. We demonstrate that temsirolimus and torin 1 effectively reduced the constitutive as well as phorbol-myristate-acetate/oncostatin-M-induced expression of mesenchymal markers (fibronectin, vimentin, and YKL40) and neural stem cell markers (Sox2, Oct4, nestin, and mushashi1). The inhibitors significantly abrogated the neurosphere-forming capacity induced by phorbol-myristate-acetate and oncostatin-M. Furthermore, we demonstrate that the drugs dephosphorylated signal transducer and activator transcription factor 3, a major regulator of mesenchymal and neural stem cell markers implicating the role of signal transducer and activator transcription factor 3 in the inhibitory action of these drugs. The findings demonstrate the potential of mammalian target of rapamycin inhibitors as "stemness-inhibiting drugs" and a promising therapeutic approach to target glioma stem cells.

Plasminogen activator inhibitor-1 is an independent prognostic factor of ovarian cancer and IMD-4482, a novel plasminogen activator inhibitor-1 inhibitor, inhibits ovarian cancer peritoneal dissemination.

PubMed

Nakatsuka, Erika; Sawada, Kenjiro; Nakamura, Koji; Yoshimura, Akihito; Kinose, Yasuto; Kodama, Michiko; Hashimoto, Kae; Mabuchi, Seiji; Makino, Hiroshi; Morii, Eiichi; Yamaguchi, Yoichi; Yanase, Takeshi; Itai, Akiko; Morishige, Ken-Ichirou; Kimura, Tadashi

2017-10-27

In the present study, the therapeutic potential of targeting plasminogen activator inhibitor-1 (PAI-1) in ovarian cancer was tested. Tissues samples from 154 cases of ovarian carcinoma were immunostained with anti-PAI-1 antibody, and the prognostic value was analyzed. Among the samples, 67% (104/154) showed strong PAI-1 expression; this was significantly associated with poor prognosis (progression-free survival: 20 vs. 31 months, P = 0.0033). In particular, among patients with stage II-IV serous adenocarcinoma, PAI-1 expression was an independent prognostic factor. The effect of a novel PAI-1 inhibitor, IMD-4482, on ovarian cancer cell lines was assessed and its therapeutic potential was examined using a xenograft mouse model of ovarian cancer. IMD-4482 inhibited in vitro cell adhesion to vitronectin in PAI-1-positive ovarian cancer cells, followed by the inhibition of extracellular signal-regulated kinase and focal adhesion kinase phosphorylation through dissociation of the PAI-urokinase receptor complex from integrin αVβ3. IMD-4482 caused G0/G1 cell arrest and inhibited the proliferation of PAI-1-positive ovarian cancer cells. In the xenograft model, IMD-4482 significantly inhibited peritoneal dissemination with the reduction of PAI-1 expression and the inhibition of focal adhesion kinase phosphorylation. Collectively, the functional inhibition of PAI-1 significantly inhibited ovarian cancer progression, and targeting PAI-1 may be a potential therapeutic strategy in ovarian cancer.

MicroRNA-1 promotes apoptosis of hepatocarcinoma cells by targeting apoptosis inhibitor-5 (API-5).

PubMed

Li, Dong; Liu, Yu; Li, Hua; Peng, Jing-Jing; Tan, Yan; Zou, Qiang; Song, Xiao-Feng; Du, Min; Yang, Zheng-Hui; Tan, Yong; Zhou, Jin-Jun; Xu, Tao; Fu, Zeng-Qiang; Feng, Jian-Qiong; Cheng, Peng; chen, Tao; Wei, Dong; Su, Xiao-Mei; Liu, Huan-Yi; Qi, Zhong-Chun; Tang, Li-Jun; Wang, Tao; Guo, Xin; Hu, Yong-He; Zhang, Tao

2015-01-02

Although microRNA-1 (miR-1) is a known liver cancer suppressor, the role of miR-1 in apoptosis of hepatoma cells has remained largely unknown. Our study shows that ectopic miR-1 overexpression induced apoptosis of liver hepatocellular carcinoma (HepG2) cells. Apoptosis inhibitor 5 (API-5) was found to be a potential regulator of miR-1 induced apoptosis, using a bioinformatics approach. Furthermore, an inverse relationship between miR-1 and API-5 expression was observed in human liver cancer tissues and adjacent normal liver tissues. Negative regulation of API-5 expression by miR-1 was demonstrated to promote apoptosis of HepG2 cells. Our study provides a novel regulatory mechanism of miR-1 in the apoptosis of hepatoma cells. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Multiple functionalized carbon quantum dots for targeting glioma and tissue imaging

NASA Astrophysics Data System (ADS)

Gao, Lipeng; Zhao, Xiao; Wang, Jing; Wang, Yiting; Yu, Lei; Peng, Hui; Zhu, Jianzhong

2018-01-01

Carbon quantum dots (CQDs) was successfully functionalized with Mal-PEG-NHS linked RGERPPR. They exhibit double functions of both tissue imaging and targeting to brain gliomas. The mean size of the functionalized CQDs about 9.0 ± 2.0 nm. The maximum absorption wavelength of the functionalized CQDs appear at 230 nm. The peak of the fluorescence spectra for the functionalized CQDs is at 460 nm, red shifted by 20 nm comparing with the unmodified CQDs. This may be due to the increased particle size. The functionalized CQDs were successfully applied to imaging and targeting gliomas.

A new O6-alkylguanine-DNA alkyltransferase inhibitor associated with a nitrosourea (cystemustine) validates a strategy of melanoma-targeted therapy in murine B16 and human-resistant M4Beu melanoma xenograft models.

PubMed

Rapp, Maryse; Maurizis, Jean C; Papon, Janine; Labarre, Pierre; Wu, Ting-Di; Croisy, Alain; Guerquin-Kern, Jean L; Madelmont, Jean C; Mounetou, Emmanuelle

2008-07-01

Chemoresistance to O(6)-alkylating agents is a major barrier to successful treatment of melanoma. It is mainly due to a DNA repair suicide protein, O(6)-alkylguanine-DNA alkyltransferase (AGT). Although AGT inactivation is a powerful clinical strategy for restoring tumor chemosensitivity, it was limited by increased toxicity to nontumoral cells resulting from a lack of tumor selectivity. Achieving enhanced chemosensitization via AGT inhibition preferably in the tumor should protect normal tissue. To this end, we have developed a strategy to target AGT inhibitors. In this study, we tested a new potential melanoma-directed AGT inhibitor [2-amino-6-(4-iodobenzyloxy)-9-[4-(diethylamino) ethylcarbamoylbenzyl] purine; IBgBZ] designed as a conjugate of O(6)-(4-iododbenzyl)guanine (IBg) as the AGT inactivator and a N,N-diethylaminoethylenebenzamido (BZ) moiety as the carrier to the malignant melanocytes. IBgBZ demonstrated AGT inactivation ability and potentiation of O(6)-alkylating agents (cystemustine, a chloroethylnitrosourea) in M4Beu highly chemoresistant human melanoma cells both in vitro and in tumor models. The biodisposition study on mice bearing B16 melanoma, the standard model for the evaluation of melanoma-directed agents, and the secondary ion mass spectrometry imaging confirmed the concentration of IBgBZ in the tumor and in particular in the intracytoplasmic melanosomes. These results validate the potential of IBgBZ as a new, more tumor-selective, AGT inhibitor in a strategy of melanoma-targeted therapy.

Trabecular meshwork ECM remodeling in glaucoma: could RAS be a target?

PubMed

Agarwal, Puneet; Agarwal, Renu

2018-06-14

Disturbances of extracellular matrix (ECM) homeostasis in trabecular meshwork (TM) cause increased aqueous outflow resistance leading to elevated intraocular pressure (IOP) in glaucomatous eyes. Therefore, restoration of ECM homeostasis is a rational approach to prevent disease progression. Since renin-angiotensin system (RAS) inhibition positively alters ECM homeostasis in cardiovascular pathologies involving pressure and volume overload, it is likely that RAS inhibitors reduce IOP primarily by restoring ECM homeostasis. Areas covered: Current evidence showing the presence of RAS components in ocular tissue and its role in regulating aqueous humor dynamics is briefly summarized. The role of RAS in ECM remodeling is discussed both in terms of its effects on ECM synthesis and its breakdown. The mechanisms of ECM remodeling involving interactions of RAS with transforming growth factor-β, Wnt/β-catenin signaling, bone morphogenic proteins, connective tissue growth factor, and matrix metalloproteinases in ocular tissue are discussed. Expert opinion: Current literature strongly indicates a significant role of RAS in ECM remodeling in TM of hypertensive eyes. Hence, IOP-lowering effect of RAS inhibitors may primarily be attributed to restoration of ECM homeostasis in aqueous outflow pathways rather than its vascular effects. However, the mechanistic targets for RAS inhibitors have much wider distribution and consequences, which remain relatively unexplored in TM.

Kinome-wide selectivity profiling of ATP-competitive mammalian target of rapamycin (mTOR) inhibitors and characterization of their binding kinetics.

PubMed

Liu, Qingsong; Kirubakaran, Sivapriya; Hur, Wooyoung; Niepel, Mario; Westover, Kenneth; Thoreen, Carson C; Wang, Jinhua; Ni, Jing; Patricelli, Matthew P; Vogel, Kurt; Riddle, Steve; Waller, David L; Traynor, Ryan; Sanda, Takaomi; Zhao, Zheng; Kang, Seong A; Zhao, Jean; Look, A Thomas; Sorger, Peter K; Sabatini, David M; Gray, Nathanael S

2012-03-23

An intensive recent effort to develop ATP-competitive mTOR inhibitors has resulted in several potent and selective molecules such as Torin1, PP242, KU63794, and WYE354. These inhibitors are being widely used as pharmacological probes of mTOR-dependent biology. To determine the potency and specificity of these agents, we have undertaken a systematic kinome-wide effort to profile their selectivity and potency using chemical proteomics and assays for enzymatic activity, protein binding, and disruption of cellular signaling. Enzymatic and cellular assays revealed that all four compounds are potent inhibitors of mTORC1 and mTORC2, with Torin1 exhibiting ∼20-fold greater potency for inhibition of Thr-389 phosphorylation on S6 kinases (EC(50) = 2 nM) relative to other inhibitors. In vitro biochemical profiling at 10 μM revealed binding of PP242 to numerous kinases, although WYE354 and KU63794 bound only to p38 kinases and PI3K isoforms and Torin1 to ataxia telangiectasia mutated, ATM and Rad3-related protein, and DNA-PK. Analysis of these protein targets in cellular assays did not reveal any off-target activities for Torin1, WYE354, and KU63794 at concentrations below 1 μM but did show that PP242 efficiently inhibited the RET receptor (EC(50), 42 nM) and JAK1/2/3 kinases (EC(50), 780 nM). In addition, Torin1 displayed unusually slow kinetics for inhibition of the mTORC1/2 complex, a property likely to contribute to the pharmacology of this inhibitor. Our results demonstrated that, with the exception of PP242, available ATP-competitive compounds are highly selective mTOR inhibitors when applied to cells at concentrations below 1 μM and that the compounds may represent a starting point for medicinal chemistry efforts aimed at developing inhibitors of other PI3K kinase-related kinases.

Exposure to acetylcholinesterase inhibitors alters the physiology and motor function of honeybees.

PubMed

Williamson, Sally M; Moffat, Christopher; Gomersall, Martha A E; Saranzewa, Nastja; Connolly, Christopher N; Wright, Geraldine A

2013-01-01

Cholinergic signaling is fundamental to neuromuscular function in most organisms. Sub-lethal doses of neurotoxic pesticides that target cholinergic signaling can alter the behavior of insects in subtle ways; their influence on non-target organisms may not be readily apparent in simple mortality studies. Beneficial arthropods such as honeybees perform sophisticated behavioral sequences during foraging that, if influenced by pesticides, could impair foraging success and reduce colony health. Here, we investigate the behavioral effects on honeybees of exposure to a selection of pesticides that target cholinergic signaling by inhibiting acetylcholinesterase (AChE). To examine how continued exposure to AChE inhibitors affected motor function, we fed adult foraging worker honeybees sub-lethal concentrations of these compounds in sucrose solution for 24 h. Using an assay for locomotion in bees, we scored walking, stopped, grooming, and upside down behavior continuously for 15 min. At a 10 nM concentration, all the AChE inhibitors caused similar effects on behavior, notably increased grooming activity and changes in the frequency of bouts of behavior such as head grooming. Coumaphos caused dose-dependent effects on locomotion as well as grooming behavior, and a 1 μM concentration of coumaphos induced symptoms of malaise such as abdomen grooming and defecation. Biochemical assays confirmed that the four compounds we assayed (coumaphos, aldicarb, chlorpyrifos, and donepezil) or their metabolites acted as AChE inhibitors in bees. Furthermore, we show that transcript expression levels of two honeybee AChE inhibitors were selectively upregulated in the brain and in gut tissues in response to AChE inhibitor exposure. The results of our study imply that the effects of pesticides that rely on this mode of action have subtle yet profound effects on physiological effects on behavior that could lead to reduced survival.

Exposure to Acetylcholinesterase Inhibitors Alters the Physiology and Motor Function of Honeybees

PubMed Central

Williamson, Sally M.; Moffat, Christopher; Gomersall, Martha A. E.; Saranzewa, Nastja; Connolly, Christopher N.; Wright, Geraldine A.

2013-01-01

Cholinergic signaling is fundamental to neuromuscular function in most organisms. Sub-lethal doses of neurotoxic pesticides that target cholinergic signaling can alter the behavior of insects in subtle ways; their influence on non-target organisms may not be readily apparent in simple mortality studies. Beneficial arthropods such as honeybees perform sophisticated behavioral sequences during foraging that, if influenced by pesticides, could impair foraging success and reduce colony health. Here, we investigate the behavioral effects on honeybees of exposure to a selection of pesticides that target cholinergic signaling by inhibiting acetylcholinesterase (AChE). To examine how continued exposure to AChE inhibitors affected motor function, we fed adult foraging worker honeybees sub-lethal concentrations of these compounds in sucrose solution for 24 h. Using an assay for locomotion in bees, we scored walking, stopped, grooming, and upside down behavior continuously for 15 min. At a 10 nM concentration, all the AChE inhibitors caused similar effects on behavior, notably increased grooming activity and changes in the frequency of bouts of behavior such as head grooming. Coumaphos caused dose-dependent effects on locomotion as well as grooming behavior, and a 1 μM concentration of coumaphos induced symptoms of malaise such as abdomen grooming and defecation. Biochemical assays confirmed that the four compounds we assayed (coumaphos, aldicarb, chlorpyrifos, and donepezil) or their metabolites acted as AChE inhibitors in bees. Furthermore, we show that transcript expression levels of two honeybee AChE inhibitors were selectively upregulated in the brain and in gut tissues in response to AChE inhibitor exposure. The results of our study imply that the effects of pesticides that rely on this mode of action have subtle yet profound effects on physiological effects on behavior that could lead to reduced survival. PMID:23386834

Biochemical and Structural Analysis of Inhibitors Targeting the ADC-7 Cephalosporinase of Acinetobacter baumannii

DOE PAGES

Powers, Rachel A.; Swanson, Hollister C.; Taracila, Magdalena A.; ...

2014-11-07

β-Lactam resistance in Acinetobacter baumannii presents one of the greatest challenges to contemporary antimicrobial chemotherapy. Much of this resistance to cephalosporins derives from the expression of the class C β-lactamase enzymes, known as Acinetobacter-derived cephalosporinases (ADCs). Currently, β-lactamase inhibitors are structurally similar to β-lactam substrates and are not effective inactivators of this class C cephalosporinase. Herein, two boronic acid transition state inhibitors (BATSIs S02030 and SM23) that are chemically distinct from β-lactams were designed and tested for inhibition of ADC enzymes. BATSIs SM23 and S02030 bind with high affinity to ADC-7, a chromosomal cephalosporinase from Acinetobacter baumannii (K i =more » 21.1 ± 1.9 nM and 44.5 ± 2.2 nM, respectively). The X-ray crystal structures of ADC-7 were determined in both the apo form (1.73 Å resolution) and in complex with S02030 (2.0 Å resolution). In the complex, S02030 makes several canonical interactions: the O1 oxygen of S02030 is bound in the oxyanion hole, and the R1 amide group makes key interactions with conserved residues Asn152 and Gln120. In addition, the carboxylate group of the inhibitor is meant to mimic the C 3/C 4 carboxylate found in β-lactams. The C 3/C 4 carboxylate recognition site in class C enzymes is comprised of Asn346 and Arg349 (AmpC numbering), and these residues are conserved in ADC-7. Interestingly, in the ADC-7/S02030 complex, the inhibitor carboxylate group is observed to interact with Arg340, a residue that distinguishes ADC-7 from the related class C enzyme AmpC. A thermodynamic analysis suggests that ΔH driven compounds may be optimized to generate new lead agents. In conclusion, the ADC-7/BATSI complex provides insight into recognition of non-β-lactam inhibitors by ADC enzymes and offers a starting point for the structure-based optimization of this class of novel β-lactamase inhibitors against a key resistance target.« less

Acquired resistance and clonal evolution in melanoma during BRAF inhibitor therapy

PubMed Central

Kong, Xiangju; Hong, Aayoung; Koya, Richard C.; Moriceau, Gatien; Chodon, Thinle; Guo, Rongqing; Johnson, Douglas B.; Dahlman, Kimberly B.; Kelley, Mark C.; Kefford, Richard F.; Chmielowski, Bartosz; Glaspy, John A.; Sosman, Jeffrey A.; van Baren, Nicolas; Long, Georgina V.; Ribas, Antoni; Lo, Roger S.

2013-01-01

BRAF inhibitors elicit rapid anti-tumor responses in the majority of patients with V600BRAF mutant melanoma, but acquired drug resistance is almost universal. We sought to identify the core resistance pathways and the extent of tumor heterogeneity during disease progression. We show that MAPK reactivation mechanisms were detected among 70% of disease-progressive tissues, with RAS mutations, mutant BRAF amplification and alternative splicing being most common. We also detected PI3K-PTEN-AKT-upregulating genetic alterations among 22% of progressive melanomas. Distinct molecular lesions, in both core drug escape pathways, were commonly detected concurrently in the same tumor or among multiple tumors from the same patient. Beyond harboring extensively heterogeneous resistance mechanisms, melanoma re-growth emerging from BRAF inhibitor selection displayed branched evolution marked by altered mutational spectra/signatures and increased fitness. Thus, melanoma genomic heterogeneity contributes significantly to BRAF inhibitor treatment failure, implying upfront, co-targeting of two core pathways as an essential strategy for durable responses. PMID:24265155

Biomimetic proteolipid vesicles for targeting inflamed tissues

NASA Astrophysics Data System (ADS)

Molinaro, R.; Corbo, C.; Martinez, J. O.; Taraballi, F.; Evangelopoulos, M.; Minardi, S.; Yazdi, I. K.; Zhao, P.; De Rosa, E.; Sherman, M. B.; de Vita, A.; Toledano Furman, N. E.; Wang, X.; Parodi, A.; Tasciotti, E.

2016-09-01

A multitude of micro- and nanoparticles have been developed to improve the delivery of systemically administered pharmaceuticals, which are subject to a number of biological barriers that limit their optimal biodistribution. Bioinspired drug-delivery carriers formulated by bottom-up or top-down strategies have emerged as an alternative approach to evade the mononuclear phagocytic system and facilitate transport across the endothelial vessel wall. Here, we describe a method that leverages the advantages of bottom-up and top-down strategies to incorporate proteins derived from the leukocyte plasma membrane into lipid nanoparticles. The resulting proteolipid vesicles--which we refer to as leukosomes--retained the versatility and physicochemical properties typical of liposomal formulations, preferentially targeted inflamed vasculature, enabled the selective and effective delivery of dexamethasone to inflamed tissues, and reduced phlogosis in a localized model of inflammation.

Targeting KRAS-mutant non-small cell lung cancer with the Hsp90 inhibitor ganetespib.

PubMed

Acquaviva, Jaime; Smith, Donald L; Sang, Jim; Friedland, Julie C; He, Suqin; Sequeira, Manuel; Zhang, Chaohua; Wada, Yumiko; Proia, David A

2012-12-01

Mutant KRAS is a feature of more than 25% of non-small cell lung cancers (NSCLC) and represents one of the most prevalent oncogenic drivers in this disease. NSCLC tumors with oncogenic KRAS respond poorly to current therapies, necessitating the pursuit of new treatment strategies. Targeted inhibition of the molecular chaperone Hsp90 results in the coordinated blockade of multiple oncogenic signaling pathways in tumor cells and has thus emerged as an attractive avenue for therapeutic intervention in human malignancies. Here, we examined the activity of ganetespib, a small-molecule inhibitor of Hsp90 currently in clinical trials for NSCLCs in a panel of lung cancer cell lines harboring a diverse spectrum of KRAS mutations. In vitro, ganetespib was potently cytotoxic in all lines, with concomitant destabilization of KRAS signaling effectors. Combinations of low-dose ganetespib with MEK or PI3K/mTOR inhibitors resulted in superior cytotoxic activity than single agents alone in a subset of mutant KRAS cells, and the antitumor efficacy of ganetespib was potentiated by cotreatment with the PI3K/mTOR inhibitor BEZ235 in A549 xenografts in vivo. At the molecular level, ganetespib suppressed activating feedback signaling loops that occurred in response to MEK and PI3K/mTOR inhibition, although this activity was not the sole determinant of combinatorial benefit. In addition, ganetespib sensitized mutant KRAS NSCLC cells to standard-of-care chemotherapeutics of the antimitotic, topoisomerase inhibitor, and alkylating agent classes. Taken together, these data underscore the promise of ganetespib as a single-agent or combination treatment in KRAS-driven lung tumors.

Proteolytic inactivation of tissue factor pathway inhibitor by bacterial omptins

PubMed Central

Yun, Thomas H.; Cott, Jessica E.; Tapping, Richard I.; Slauch, James M.

2009-01-01

The immune response to infection includes activation of the blood clotting system, leading to extravascular fibrin deposition to limit the spread of invasive microorganisms. Some bacteria have evolved mechanisms to counteract this host response. Pla, a member of the omptin family of Gram-negative bacterial proteases, promotes the invasiveness of the plague bacterium, Yersinia pestis, by activating plasminogen to plasmin to digest fibrin. We now show that the endogenous anticoagulant tissue factor pathway inhibitor (TFPI) is also highly sensitive to proteolysis by Pla and its orthologs OmpT in Escherichia coli and PgtE in Salmonella enterica serovar Typhimurium. Using gene deletions, we demonstrate that bacterial inactivation of TFPI requires omptin expression. TFPI inactivation is mediated by proteolysis since Western blot analysis showed that TFPI cleavage correlated with loss of anticoagulant function in clotting assays. Rates of TFPI inactivation were much higher than rates of plasminogen activation, indicating that TFPI is a better substrate for omptins. We hypothesize that TFPI has evolved sensitivity to proteolytic inactivation by bacterial omptins to potentiate procoagulant responses to bacterial infection. This may contribute to the hemostatic imbalance in disseminated intravascular coagulation and other coagulopathies accompanying severe sepsis. PMID:18988866

Novel small molecule inhibitors of 3-phosphoinositide-dependent kinase-1.

PubMed

Feldman, Richard I; Wu, James M; Polokoff, Mark A; Kochanny, Monica J; Dinter, Harald; Zhu, Daguang; Biroc, Sandra L; Alicke, Bruno; Bryant, Judi; Yuan, Shendong; Buckman, Brad O; Lentz, Dao; Ferrer, Mike; Whitlow, Marc; Adler, Marc; Finster, Silke; Chang, Zheng; Arnaiz, Damian O

2005-05-20

The phosphoinositide 3-kinase/3-phosphoinositide-dependent kinase 1 (PDK1)/Akt signaling pathway plays a key role in cancer cell growth, survival, and tumor angiogenesis and represents a promising target for anticancer drugs. Here, we describe three potent PDK1 inhibitors, BX-795, BX-912, and BX-320 (IC(50) = 11-30 nm) and their initial biological characterization. The inhibitors blocked PDK1/Akt signaling in tumor cells and inhibited the anchorage-dependent growth of a variety of tumor cell lines in culture or induced apoptosis. A number of cancer cell lines with elevated Akt activity were >30-fold more sensitive to growth inhibition by PDK1 inhibitors in soft agar than on tissue culture plastic, consistent with the cell survival function of the PDK1/Akt signaling pathway, which is particularly important for unattached cells. BX-320 inhibited the growth of LOX melanoma tumors in the lungs of nude mice after injection of tumor cells into the tail vein. The effect of BX-320 on cancer cell growth in vitro and in vivo indicates that PDK1 inhibitors may have clinical utility as anticancer agents.

Introducing a simple model system for binding studies of known and novel inhibitors of AMPK: a therapeutic target for prostate cancer.

PubMed

Kumar, Rakesh; Maurya, Ranjana; Saran, Shweta

2018-02-23

Prostate cancer (PC) is one of the leading cancers in men, raising a serious health issue worldwide. Due to lack of suitable biomarker, their inhibitors and the platform for testing those inhibitors result in poor prognosis of PC. AMP-activated protein kinase (AMPK) is a highly conserved protein kinase found in eukaryotes that is involved in growth and development, and also acts as a therapeutic target for PC. The aim of the present study is to identify novel potent inhibitors of AMPK and propose a simple cellular model system for understanding its biology. Structural modelling and MD simulations were performed to construct and refine the 3D models of Dictyostelium and human AMPK. Binding mechanisms of different drug compounds were studied by performing molecular docking, molecular dynamics and MM-PBSA methods. Two novel drugs were isolated having higher binding affinity over the known drugs and hydrophobic forces that played a key role during protein-ligand interactions. The study also explored the simple cellular model system for drug screening and understanding the biology of a therapeutic target by performing in vitro experiments.

Discovering Small Molecule Inhibitors Targeted to Ligand-Stimulated RAGE-DIAPH1 Signaling Transduction

NASA Astrophysics Data System (ADS)

Pan, Jinhong

The receptor of advanced glycation end product (RAGE) is a multiligand receptor of the immunoglobulin superfamily of cell surface molecules, which plays an important role in immune responses. Full-length RAGE includes three extracellular immunoglobulin domains, a transmembrane domain and an intracellular domain. It is a pattern recognition receptor that can bind diverse ligands. NMR spectroscopy and x-ray crystallization studies of the extracellular domains of RAGE indicate that RAGE ligands bind by distinct charge- and hydrophobicity-dependent mechanisms. It is found that calgranulin binding to the C1C2 domain or AGEs binding to the V domain activates extracellular signaling, which triggers interactions of the RAGE cytoplasmic tail (ctRAGE) with intracellular effector, such as diaphanous 1 (DIAPH1), to initiate signal transduction cascades. ctRAGE is essential for RAGE-ligand-mediated signal transduction and consequent modulation of gene expression and cellular properties. RAGE is over-expressed in diseased tissues of most RAGE-associated pathogenic conditions, such as complications of Alzheimer's diseases, diabetes, vascular diseases, inflammation, cancers and neurodegeneration. They are the major diseases affecting a large population worldwide. RAGE can function as a biomarker or drug target for these diseases. The cytoplasmic tail of RAGE can be used as a drug target to inhibit RAGE-induced intracellular signaling by small molecule inhibitors to treat RAGE-associated diseases. We developed a high throughput screening assay with which we probed a small molecule library of 58,000 compounds to find that 777 small molecules displayed 50% inhibition and 97 compounds demonstrated dose-dependent inhibition of the binding of ctRAGE-DIAPH1. Eventually, there were 13 compounds which displayed dose-dependent inhibition of ctRAGE binding to DIAPH1 and direct binding to ctRAGE analyzed by 15N HSQC-NMR and native tryptophan fluorescence titration experiments; thus, they were

Enhanced migration of tissue inhibitor of metalloproteinase overexpressing hepatoma cells is attributed to gelatinases: Relevance to intracellular signaling pathways

PubMed Central

Roeb, Elke; Bosserhoff, Anja-Katrin; Hamacher, Sabine; Jansen, Bettina; Dahmen, Judith; Wagner, Sandra; Matern, Siegfried

2005-01-01

AIM: To study the effect of gelatinases (especially MMP-9) on migration of tissue inhibitor of metalloproteinase (TIMP-1) overexpressing hepatoma cells. METHODS: Wild type HepG2 cells, cells stably transfected with TIMP-1 and TIMP-1 antagonist (MMP-9-H401A, a catalytically inactive matrix metalloproteinase (MMP) which still binds and neutralizes TIMP-1) were incubated in Boyden chambers either with or without Galardin (a synthetic inhibitor of MMP-1, -2, -3, -8, -9) or a specific inhibitor of gelatinases. RESULTS: Compared to wild type HepG2 cells, the cells overexpressing TIMP-1 showed 115% migration (P<0.05) and the cells overexpressing MMP-9-H401A showed 62% migration (P<0.01). Galardin reduced cell migration dose dependently in all cases. The gelatinase inhibitor reduced migration in TIMP-1 overexpressing cells predominantly. Furthermore, we examined intracellular signal transduction pathways of TIMP-1-dependent HepG2 cells. TIMP-1 deactivates cell signaling pathways of MMP-2 and MMP-9 involving p38 mitogen-activated protein kinase. Specific blockade of the ERK pathway suppresses gelatinase expression either in the presence or absence of TIMP-1. CONCLUSION: Overexpressing functional TIMP-1- enhanced migration of HepG2-TIMP-1 cells depends on enhanced MMP-activity, especially MMP-9. PMID:15754388

Dual kinase-bromodomain inhibitors for rationally designed polypharmacology

PubMed Central

Ciceri, Pietro; Müller, Susanne; O’Mahony, Alison; Fedorov, Oleg; Filippakopoulos, Panagis; Hunt, Jeremy P.; Lasater, Elisabeth A.; Pallares, Gabriel; Picaud, Sarah; Wells, Christopher; Martin, Sarah; Wodicka, Lisa M.; Shah, Neil P.; Treiber, Daniel K.; Knapp, Stefan

2014-01-01

Concomitant inhibition of multiple cancer-driving kinases is an established strategy to improve the durability of clinical responses to targeted therapies. The difficulty of discovering kinase inhibitors with an appropriate multi-target profile has, however, necessitated the application of combination therapies, which can pose significant clinical development challenges. Epigenetic reader domains of the bromodomain family have recently emerged as novel targets for cancer therapy. Here we report that several clinical kinase inhibitors also inhibit bromodomains with therapeutically relevant potencies and are best classified as dual kinase/bromodomain inhibitors. Nanomolar activity on BRD4 by BI-2536 and TG-101348, clinical PLK1 and JAK2/FLT3 kinase inhibitors, respectively, is particularly noteworthy as these combinations of activities on independent oncogenic pathways exemplify a novel strategy for rational single agent polypharmacological targeting. Furthermore, structure-activity relationships and co-crystal structures identify design features that enable a general platform for the rational design of dual kinase/bromodomain inhibitors. PMID:24584101

Phytochemicals as multi-target inhibitors of the inflammatory pathway- A modeling and experimental study.

PubMed

Devi, Nisha S; Ramanan, Meera; Paragi-Vedanthi, Padmapriya; Doble, Mukesh

2017-03-11

The arachidonic acid pathway consists of several enzymes and targeting them is favored for developing anti-inflammatory drugs. However, till date the current drugs are generally active against a single target, leading to undesirable side-effects. Phytochemicals are known to inhibit multiple targets simultaneously and hence, an attempt is made here to investigate their suitability. A pharmacophore based study is performed with three sets of reported phytochemicals namely, dual 5-LOX/mPGES1, alkaloids and FLAP inhibitors. The analysis indicated that phenylpropanoids (including ferulic acid) and benzoic acids derivatives, and berberine mapped onto these pharmacophores with three hydrophobic centroids and an acceptor feature. 2,4,5-trimethoxy (7) and 3,4-dimethoxy cinnamic acids (8) mapped onto all the three pharmacophores. Experimental studies indicated that berberine inhibited 5-LOX (100 μM) and PGE 2 (50 μM) production by 72.2 and 72.0% and ferulic acid by 74.3 and 54.4% respectively. This approach offers a promising theoretical combined with experimental strategy for designing novel molecules against inflammatory enzymes. Copyright © 2017 Elsevier Inc. All rights reserved.

Evolution of NADPH Oxidase Inhibitors: Selectivity and Mechanisms for Target Engagement.

PubMed

Altenhöfer, Sebastian; Radermacher, Kim A; Kleikers, Pamela W M; Wingler, Kirstin; Schmidt, Harald H H W

2015-08-10

Oxidative stress, an excess of reactive oxygen species (ROS) production versus consumption, may be involved in the pathogenesis of different diseases. The only known enzymes solely dedicated to ROS generation are nicotinamide adenine dinucleotide phosphate (NADPH) oxidases with their catalytic subunits (NOX). After the clinical failure of most antioxidant trials, NOX inhibitors are the most promising therapeutic option for diseases associated with oxidative stress. Historical NADPH oxidase inhibitors, apocynin and diphenylene iodonium, are un-specific and not isoform selective. Novel NOX inhibitors stemming from rational drug discovery approaches, for example, GKT137831, ML171, and VAS2870, show improved specificity for NADPH oxidases and moderate NOX isoform selectivity. Along with NOX2 docking sequence (NOX2ds)-tat, a peptide-based inhibitor, the use of these novel small molecules in animal models has provided preliminary in vivo evidence for a pathophysiological role of specific NOX isoforms. Here, we discuss whether novel NOX inhibitors enable reliable validation of NOX isoforms' pathological roles and whether this knowledge supports translation into pharmacological applications. Modern NOX inhibitors have increased the evidence for pathophysiological roles of NADPH oxidases. However, in comparison to knockout mouse models, NOX inhibitors have limited isoform selectivity. Thus, their use does not enable clear statements on the involvement of individual NOX isoforms in a given disease. The development of isoform-selective NOX inhibitors and biologicals will enable reliable validation of specific NOX isoforms in disease models other than the mouse. Finally, GKT137831, the first NOX inhibitor in clinical development, is poised to provide proof of principle for the clinical potential of NOX inhibition.

Induction of Tissue Factor Pathway Inhibitor 2 by hCG Regulates Periovulatory Gene Expression and Plasmin Activity.

PubMed

Puttabyatappa, Muraly; Al-Alem, Linah F; Zakerkish, Farnosh; Rosewell, Katherine L; Brännström, Mats; Curry, Thomas E

2017-01-01

Increased proteolytic activity is a key event that aids in breakdown of the follicular wall to permit oocyte release. How the protease activity is regulated is still unknown. We hypothesize that tissue factor pathway inhibitor 2 (TFPI2), a Kunitz-type serine protease inhibitor, plays a role in regulating periovulatory proteolytic activity as in other tissues. TFPI2 is secreted into the extracellular matrix (ECM) where it is postulated to regulate physiological ECM remodeling. The expression profile of TFPI2 during the periovulatory period was assessed utilizing a well-characterized human menstrual cycle model and a gonadotropin-primed rat model. Administration of an ovulatory dose of human chorionic gonadotropin (hCG) increased TFPI2 expression dramatically in human and rat granulosa and theca cells. This increase in Tfpi2 expression in rat granulosa cells required hCG-mediated epidermal growth factor, protein kinase A, mitogen-activated protein kinase (MAPK) 1/2, p38 MAPK and protease activated receptor 1-dependent cell signaling. A small interferingRNA-mediated knockdown of TFPI2 in rat granulosa cells resulted in increased plasmin activity in the granulosa cell conditioned media. Knockdown of TFPI2 also reduced expression of multiple genes including interleukin 6 (Il6) and amphiregulin (Areg). Overexpression of TFPI2 using an adenoviral vector partially restored the expression of Il6 and Areg in TFPI2 siRNA treated rat granulosa cells. These data support the hypothesis that TFPI2 is important for moderating plasmin activity and regulating granulosa cell gene expression during the periovulatory period. We, therefore, propose that through these actions, TFPI2 aids in the tissue remodeling taking place during follicular rupture and corpus luteum formation. Copyright © 2017 by the Endocrine Society.

Tissue factor pathway inhibitor 2 is found in skin and its C-terminal region encodes for antibacterial activity.

PubMed

Papareddy, Praveen; Kalle, Martina; Sørensen, Ole E; Lundqvist, Katarina; Mörgelin, Matthias; Malmsten, Martin; Schmidtchen, Artur

2012-01-01

Tissue factor pathway inhibitor 2 (TFPI-2) is a matrix-associated serine protease inhibitor with an enigmatic function in vivo. Here, we describe that TFPI-2 is present in fibrin of wounds and also expressed in skin, where it is up-regulated upon wounding. Neutrophil elastase cleaved TFPI-2, and a C-terminal fragment was found to bind to bacteria. Similarly, a prototypic peptide representing this C-terminal part, EDC34, bound to bacteria and bacterial lipopolysaccharide, and induced bacterial permeabilization. The peptide also induced leakage in artificial liposomes, and displayed a random coil conformation upon interactions with liposomes as well as lipopolysaccharide. EDC34 was antibacterial against both Gram-negative and Gram-positive bacteria in physiological buffer conditions. The results demonstrate that the C-terminus of TFPI-2 encodes for antimicrobial activity, and may be released during wounding.

Neuroendocrine tumors: insights into innovative therapeutic options and rational development of targeted therapies.

PubMed

Barbieri, Federica; Albertelli, Manuela; Grillo, Federica; Mohamed, Amira; Saveanu, Alexandru; Barlier, Anne; Ferone, Diego; Florio, Tullio

2014-04-01

Neuroendocrine tumors (NETs) are heterogeneous neoplasms with respect to molecular characteristics and clinical outcome. Although slow-growing, NETs are often late diagnosed, already showing invasion of adjacent tissues and metastases. Precise knowledge of NET biological and molecular features has opened the door to the identification of novel pharmacological targets. Therapeutic options include somatostatin analogs, alone or in combination with interferon-α, multi-targeted tyrosine kinase inhibitors (e.g. sunitinib) or mammalian target of rapamycin (mTOR) inhibitors (e.g. everolimus). Antiangiogenic approaches and anti insulin-like growth factor receptor (IGFR) compounds have been also proposed as combination therapies with the aforementioned compounds. This review will focus on recent studies that have improved therapeutic strategies in NETs, discussing management challenges such as drug resistance development as well as focusing on the need for predictive biomarkers to design distinct drug combinations and optimize pharmacological control. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cosmic ray heavy ion LET mapping for aluminum, silicon, and tissue targets

NASA Technical Reports Server (NTRS)

Stassinopoulos, E. G.; Barth, J. M.; Jordan, T. M.

1987-01-01

Linear energy transfer (LET) values in aluminum, silicon, and tissue targets have been calculated for 31 galactic cosmic ray ion species in eight different units. The values are described for single event upset (SEU) effect assessments or radiobiological evaluations. The data are presented in graphical and tabular form.

Altered gene expression in rat mesenteric tissue following in vivo exposure to a phosphodiesterase 4 inhibitor

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

Dagues, Nicolas; Pawlowski, Valerie; Guigon, Ghislaine

Vascular injury is a relatively common finding during the pre-clinical toxicity testing of drugs. The mechanisms of the injury are poorly understood and in turn, sensitive and specific biomarkers for pre-clinical and clinical monitoring do not exist. The present study was undertaken to investigate the molecular mechanisms of drug-induced vascular injury in mesenteric tissue of rats treated with the selective phosphodiesterase 4 (PDE4) inhibitor CI-1044. In a time-course study, male Sprague Dawley rats were given daily doses of 40 or 80 mg/kg for 1, 2 or 3 successive days and were euthanized the following day. Gene expression profiles in mesentericmore » tissue were determined using Affymetrix RG{sub U}34A microarrays and fibrinogen and cytokine measurements were performed in blood samples. Hierarchical clustering analysis produced a clear pattern separation of the animals with inflammation, animal with inflammation and necrosis and animals without any lesion. Genes associated with inflammation, procoagulation, extracellular matrix remodeling were up-regulated. An altered expression of genes involved in vascular tone regulation, lipid and glucose metabolism was also observed. Selected genes expression changes were confirmed by TaqMan real-time RT-PCR. The inflammatory process was also detected in the bloodstream at the protein level since fibrinogen, IL6 and IL1{beta} concentrations were increased in treated animals. Overall, the present study reveals several molecular changes supporting the hypothesis by which PDE4 inhibitor-induced vascular lesions in rats are triggered by an inflammatory mechanism and/or a vascular tone dysregulation.« less

Apoptosis inhibitor of macrophage (AIM) is required for obesity-associated recruitment of inflammatory macrophages into adipose tissue

PubMed Central

Kurokawa, Jun; Nagano, Hiromichi; Ohara, Osamu; Kubota, Naoto; Kadowaki, Takashi; Arai, Satoko; Miyazaki, Toru

2011-01-01

Infiltration of inflammatory macrophages into adipose tissues with the progression of obesity triggers insulin resistance and obesity-related metabolic diseases. We recently reported that macrophage-derived apoptosis inhibitor of macrophage (AIM) protein is increased in blood in line with obesity progression and is incorporated into adipocytes, thereby inducing lipolysis in adipose tissue. Here we show that such a response is required for the recruitment of adipose tissue macrophages. In vitro, AIM-dependent lipolysis induced an efflux of palmitic and stearic acids from 3T3-L1 adipocytes, thereby stimulating chemokine production in adipocytes via activation of toll-like receptor 4 (TLR4). In vivo administration of recombinant AIM to TLR4-deficient (TLR4−/−) mice resulted in induction of lipolysis without chemokine production in adipose tissues. Consistently, mRNA levels for the chemokines that affect macrophages were far lower in AIM-deficient (AIM−/−) than in wild-type (AIM+/+) obese adipose tissue. This reduction in chemokine production resulted in a marked prevention of inflammatory macrophage infiltration into adipose tissue in obese AIM−/− mice, although these mice showed more advanced obesity than AIM+/+ mice on a high-fat diet. Diminished macrophage infiltration resulted in decreased inflammation locally and systemically in obese AIM−/− mice, thereby protecting them from insulin resistance and glucose intolerance. These results indicate that the increase in blood AIM is a critical event for the initiation of macrophage recruitment into adipose tissue, which is followed by insulin resistance. Thus, AIM suppression might be therapeutically applicable for the prevention of obesity-related metabolic disorders. PMID:21730133

Coming full circle: 70 years of chronic lymphocytic leukemia cell redistribution, from glucocorticoids to inhibitors of B-cell receptor signaling

PubMed Central

Montserrat, Emili

2013-01-01

Chronic lymphocytic leukemia (CLL) cells proliferate in pseudofollicles within the lymphatic tissues, where signals from the microenvironment and BCR signaling drive the expansion of the CLL clone. Mobilization of tissue-resident cells into the blood removes CLL cells from this nurturing milieu and sensitizes them to cytotoxic drugs. This concept recently gained momentum after the clinical activity of kinase inhibitors that target BCR signaling (spleen tyrosine kinase, Bruton tyrosine kinase, PI3Kδ inhibitors) was established. Besides antiproliferative activity, these drugs cause CLL cell redistribution with rapid lymph node shrinkage, along with a transient surge in lymphocytosis, before inducing objective remissions. Inactivation of critical CLL homing mechanism (chemokine receptors, adhesion molecules), thwarting tissue retention and recirculation into the tissues, appears to be the basis for this striking clinical activity. This effect of BCR-signaling inhibitors resembles redistribution of CLL cells after glucocorticoids, described as early as in the 1940s. As such, we are witnessing a renaissance of the concept of leukemia cell redistribution in modern CLL therapy. Here, we review the molecular basis of CLL cell trafficking, homing, and redistribution and similarities between old and new drugs affecting these processes. In addition, we outline how these discoveries are changing our understanding of CLL biology and therapy. PMID:23264597

Tissue Inhibitor of Metalloproteinase-2 Suppresses Collagen Synthesis in Cultured Keloid Fibroblasts

PubMed Central

Dohi, Teruyuki; Aoki, Masayo; Ogawa, Rei; Akaishi, Satoshi; Shimada, Takashi; Okada, Takashi; Hyakusoku, Hiko

2015-01-01

Background: Keloids are defined as a kind of dermal fibroproliferative disorder resulting from the accumulation of collagen. In the remodeling of extracellular matrix, the balance between matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) is as critical as the proper production of extracellular matrix. We investigate the role of TIMPs and MMPs in the pathogenesis of keloids and examine the therapeutic potential of TIMP-2. Methods: The expression of TIMPs and MMPs in most inflamed parts of cultured keloid fibroblasts (KFs) and peripheral normal skin fibroblasts (PNFs) in the same individuals and the reactivity of KFs to cyclic mechanical stretch were analyzed by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay (n = 7). To evaluate the effect of treating KFs with TIMP-2, collagen synthesis was investigated by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, and microscopic analysis was used to examine the treatment effects of TIMP-2 on ex vivo cultures of keloid tissue (n = 6). Results: TIMP-2 was downregulated in cultured KFs compared with PNFs in the same individuals, and the reduction in TIMP-2 was exacerbated by cyclic mechanical stretch. Administration of TIMP-2 (200 or 300 ng/mL) significantly suppressed expression of Col1A2 and Col3A1 mRNA and collagen type I protein in KFs. TIMP-2 also significantly reduced the skin dermal and collagen bundle thickness in ex vivo cultures of keloid tissue. Conclusion: These results indicated that downregulation of TIMP-2 in KFs is a crucial event in the pathogenesis of keloids, and the TIMP-2 would be a promising candidate for the treatment of keloids. PMID:26495233

Targeting AMPK-ULK1-mediated autophagy for combating BET inhibitor resistance in acute myeloid leukemia stem cells.

PubMed

Jang, Ji Eun; Eom, Ju-In; Jeung, Hoi-Kyung; Cheong, June-Won; Lee, Jung Yeon; Kim, Jin Seok; Min, Yoo Hong

2017-04-03

Bromodomain and extraterminal domain (BET) inhibitors are promising epigenetic agents for the treatment of various subsets of acute myeloid leukemia (AML). However, the resistance of leukemia stem cells (LSCs) to BET inhibitors remains a major challenge. In this study, we evaluated the mechanisms underlying LSC resistance to the BET inhibitor JQ1. We evaluated the levels of apoptosis and macroautophagy/autophagy induced by JQ1 in LSC-like leukemia cell lines and primary CD34 + CD38 - leukemic blasts obtained from AML cases with normal karyotype without recurrent mutations. JQ1 effectively induced apoptosis in a concentration-dependent manner in JQ1-sensitive AML cells. However, in JQ1-resistant AML LSCs, JQ1 induced little apoptosis and led to upregulation of BECN1/Beclin 1, increased LC3 lipidation, formation of autophagosomes, and downregulation of SQSTM1/p62. Inhibition of autophagy by pharmacological inhibitors or knockdown of BECN1 using specific siRNA enhanced JQ1-induced apoptosis in resistant cells, indicating that prosurvival autophagy occurred in these cells. Independent of MTOR signaling, activation of the AMPK (p-Thr172)-ULK1 (p-Ser555) pathway was found to be associated with JQ1-induced autophagy in resistant cells. AMPK inhibition using the pharmacological inhibitor compound C or by knockdown of PRKAA/AMPKα suppressed autophagy and promoted JQ1-induced apoptosis in AML LSCs. These findings revealed that prosurvival autophagy was one of the mechanisms involved in the resistance of AML LSCs to JQ1. Targeting the AMPK-ULK1 pathway or inhibition of autophagy could be an effective therapeutic strategy for combating resistance to BET inhibitors in AML and other types of cancer.

Tyrosine kinase inhibitors and mesenchymal stromal cells: effects on self-renewal, commitment and functions

PubMed Central

Borriello, Adriana; Caldarelli, Ilaria; Bencivenga, Debora; Stampone, Emanuela; Perrotta, Silverio; Oliva, Adriana; Ragione, Fulvio Della

2017-01-01

The hope of selectively targeting cancer cells by therapy and eradicating definitively malignancies is based on the identification of pathways or metabolisms that clearly distinguish “normal” from “transformed” phenotypes. Some tyrosine kinase activities, specifically unregulated and potently activated in malignant cells, might represent important targets of therapy. Consequently, tyrosine kinase inhibitors (TKIs) might be thought as the “vanguard” of molecularly targeted therapy for human neoplasias. Imatinib and the successive generations of inhibitors of Bcr-Abl1 kinase, represent the major successful examples of TKI use in cancer treatment. Other tyrosine kinases have been selected as targets of therapy, but the efficacy of their inhibition, although evident, is less definite. Two major negative effects exist in this therapeutic strategy and are linked to the specificity of the drugs and to the role of the targeted kinase in non-malignant cells. In this review, we will discuss the data available on the TKIs effects on the metabolism and functions of mesenchymal stromal cells (MSCs). MSCs are widely distributed in human tissues and play key physiological roles; nevertheless, they might be responsible for important pathologies. At present, bone marrow (BM) MSCs have been studied in greater detail, for both embryological origins and functions. The available data are evocative of an unexpected degree of complexity and heterogeneity of BM-MSCs. It is conceivable that this grade of intricacy occurs also in MSCs of other organs. Therefore, in perspective, the negative effects of TKIs on MSCs might represent a critical problem in long-term cancer therapies based on such inhibitors. PMID:27750212

Evaluation of cysteine proteases of Plasmodium vivax as antimalarial drug targets: sequence analysis and sensitivity to cysteine protease inhibitors.

PubMed

Na, Byoung-Kuk; Kim, Tong-Soo; Rosenthal, Philip J; Lee, Jong-Koo; Kong, Yoon

2004-10-01

Cysteine proteases perform critical roles in the life cycles of malaria parasites. In Plasmodium falciparum, treatment of cysteine protease inhibitors inhibits hemoglobin hydrolysis and blocks the parasite development in vitro and in vivo, suggesting that plasmodial cysteine proteases may be interesting targets for new chemotherapeutics. To determine whether sequence diversity may limit chemotherapy against Plasmodium vivax, we analyzed sequence variations in the genes encoding three cysteine proteases, vivapain-1, -2 and -3, in 22 wild isolates of P. vivax. The sequences were highly conserved among wild isolates. A small number of substitutions leading to amino acid changes were found, while they did not modify essential residues for the function or structure of the enzymes. The substrate specificities and sensitivities to synthetic cysteine protease inhibitors of vivapain-2 and -3 from wild isolates were also very similar. These results support the suggestion that cysteine proteases of P. vivax are promising antimalarial chemotherapeutic targets.

A Sympathetic Neuron Autonomous Role for Egr3-Mediated Gene Regulation in Dendrite Morphogenesis and Target Tissue Innervation

PubMed Central

Quach, David H.; Oliveira-Fernandes, Michelle; Gruner, Katherine A.; Tourtellotte, Warren G.

2013-01-01

Egr3 is a nerve growth factor (NGF)-induced transcriptional regulator that is essential for normal sympathetic nervous system development. Mice lacking Egr3 in the germline have sympathetic target tissue innervation abnormalities and physiologic sympathetic dysfunction similar to humans with dysautonomia. However, since Egr3 is widely expressed and has pleiotropic function, it has not been clear whether it has a role within sympathetic neurons and if so, what target genes it regulates to facilitate target tissue innervation. Here, we show that Egr3 expression within sympathetic neurons is required for their normal innervation since isolated sympathetic neurons lacking Egr3 have neurite outgrowth abnormalities when treated with NGF and mice with sympathetic neuron-restricted Egr3 ablation have target tissue innervation abnormalities similar to mice lacking Egr3 in all tissues. Microarray analysis performed on sympathetic neurons identified many target genes deregulated in the absence of Egr3, with some of the most significantly deregulated genes having roles in axonogenesis, dendritogenesis, and axon guidance. Using a novel genetic technique to visualize axons and dendrites in a subpopulation of randomly labeled sympathetic neurons, we found that Egr3 has an essential role in regulating sympathetic neuron dendrite morphology and terminal axon branching, but not in regulating sympathetic axon guidance to their targets. Together, these results indicate that Egr3 has a sympathetic neuron autonomous role in sympathetic nervous system development that involves modulating downstream target genes affecting the outgrowth and branching of sympathetic neuron dendrites and axons. PMID:23467373

Dual-Targeting Small-Molecule Inhibitors of the Staphylococcus aureus FMN Riboswitch Disrupt Riboflavin Homeostasis in an Infectious Setting.

PubMed

Wang, Hao; Mann, Paul A; Xiao, Li; Gill, Charles; Galgoci, Andrew M; Howe, John A; Villafania, Artjohn; Barbieri, Christopher M; Malinverni, Juliana C; Sher, Xinwei; Mayhood, Todd; McCurry, Megan D; Murgolo, Nicholas; Flattery, Amy; Mack, Matthias; Roemer, Terry

2017-05-18

Riboswitches are bacterial-specific, broadly conserved, non-coding RNA structural elements that control gene expression of numerous metabolic pathways and transport functions essential for cell growth. As such, riboswitch inhibitors represent a new class of potential antibacterial agents. Recently, we identified ribocil-C, a highly selective inhibitor of the flavin mononucleotide (FMN) riboswitch that controls expression of de novo riboflavin (RF, vitamin B2) biosynthesis in Escherichia coli. Here, we provide a mechanistic characterization of the antibacterial effects of ribocil-C as well as of roseoflavin (RoF), an antimetabolite analog of RF, among medically significant Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis. We provide genetic, biophysical, computational, biochemical, and pharmacological evidence that ribocil-C and RoF specifically inhibit dual FMN riboswitches, separately controlling RF biosynthesis and uptake processes essential for MRSA growth and pathogenesis. Such a dual-targeting mechanism is specifically required to develop broad-spectrum Gram-positive antibacterial agents targeting RF metabolism. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combined treatment with MAO-A inhibitor and MAO-B inhibitor increases extracellular noradrenaline levels more than MAO-A inhibitor alone through increases in beta-phenylethylamine.

PubMed

Kitaichi, Yuji; Inoue, Takeshi; Nakagawa, Shin; Boku, Shuken; Izumi, Takeshi; Koyama, Tsukasa

2010-07-10

Monoamine oxidase inhibitors (MAO inhibitors) have been widely used as antidepressants. However, it remains unclear whether a difference exists between non-selective MAO inhibitors and selective MAO-A inhibitors in terms of their antidepressant effects. Using in vivo microdialysis methods, we measured extracellular noradrenaline and serotonin levels following administration of Ro 41-1049, a reversible MAO-A inhibitor and/or lazabemide, a reversible MAO-B inhibitor in the medial prefrontal cortex (mPFC) of rats. We examined the effect of local infusion of beta-phenylethylamine to the mPFC of rats on extracellular noradrenaline and serotonin levels. Furthermore, the concentrations of beta-phenylethylamine in the tissue of the mPFC after combined treatment with Ro 41-1049 and lazabemide were measured. The Ro 41-1049 alone and the combined treatment significantly increased extracellular noradrenaline levels compared with vehicle and lazabemide alone. Furthermore, the combined treatment increased noradrenaline levels significantly more than Ro 41-1049 alone did. The Ro 41-1049 alone and the combined treatment significantly increased extracellular serotonin levels compared with vehicle and lazabemide alone, but no difference in serotonin levels was found between the combined treatment group and the Ro 41-1049 group. Local infusion of low-dose beta-phenylethylamine increased extracellular noradrenaline levels, but not that of serotonin. Only the combined treatment significantly increased beta-phenylethylamine levels in tissues of the mPFC. Our results suggest that the combined treatment with a MAO-A inhibitor and a MAO-B inhibitor strengthens antidepressant effects because the combined treatment increases extracellular noradrenaline levels more than a MAO-A inhibitor alone through increases in beta-phenylethylamine. Copyright 2010 Elsevier B.V. All rights reserved.

A covalent PIN1 inhibitor selectively targets cancer cells by a dual mechanism of action

NASA Astrophysics Data System (ADS)

Campaner, Elena; Rustighi, Alessandra; Zannini, Alessandro; Cristiani, Alberto; Piazza, Silvano; Ciani, Yari; Kalid, Ori; Golan, Gali; Baloglu, Erkan; Shacham, Sharon; Valsasina, Barbara; Cucchi, Ulisse; Pippione, Agnese Chiara; Lolli, Marco Lucio; Giabbai, Barbara; Storici, Paola; Carloni, Paolo; Rossetti, Giulia; Benvenuti, Federica; Bello, Ezia; D'Incalci, Maurizio; Cappuzzello, Elisa; Rosato, Antonio; Del Sal, Giannino

2017-06-01

The prolyl isomerase PIN1, a critical modifier of multiple signalling pathways, is overexpressed in the majority of cancers and its activity strongly contributes to tumour initiation and progression. Inactivation of PIN1 function conversely curbs tumour growth and cancer stem cell expansion, restores chemosensitivity and blocks metastatic spread, thus providing the rationale for a therapeutic strategy based on PIN1 inhibition. Notwithstanding, potent PIN1 inhibitors are still missing from the arsenal of anti-cancer drugs. By a mechanism-based screening, we have identified a novel covalent PIN1 inhibitor, KPT-6566, able to selectively inhibit PIN1 and target it for degradation. We demonstrate that KPT-6566 covalently binds to the catalytic site of PIN1. This interaction results in the release of a quinone-mimicking drug that generates reactive oxygen species and DNA damage, inducing cell death specifically in cancer cells. Accordingly, KPT-6566 treatment impairs PIN1-dependent cancer phenotypes in vitro and growth of lung metastasis in vivo.

Identification of potential PKC inhibitors through pharmacophore designing, 3D-QSAR and molecular dynamics simulations targeting Alzheimer's disease.

PubMed

Iqbal, Saleem; Anantha Krishnan, Dhanabalan; Gunasekaran, Krishnasamy

2017-12-13

Protein kinases are ubiquitously expressed as Serine/Threonine kinases, and play a crucial role in cellular activities. Protein kinases have evolved through stringent regulation mechanisms. Protein kinases are also involved in tauopathy, thus are important targets for developing Anti-Alzheimer's disease compounds. Structures with an indole scaffold turned out to be potent new leads. With the aim of developing new inhibitors for human protein kinase C, here we report the generation of four point 3D geometric featured pharmacophore model. In order to identify novel and potent PKCθ inhibitors, the pharmacophore model was screened against 80,000,00 compounds from various chemical databases such as., ZINC, SPEC, ASINEX, which resulted in 127 compound hits, and were taken for molecular docking filters (HTVS, XP docking). After in-depth analysis of binding patterns, induced fit docking (flexible) was employed for six compounds along with the cocrystallized inhibitor. Molecular docking study reveals that compound 6F found to be tight binder at the active site of PKCθ as compared to the cocrystal and has occupancy of 90 percentile. MM-GBSA also confirmed the potency of the compound 6F as better than cocrystal. Molecular dynamics results suggest that compound 6F showed good binding stability of active sites residues similar to cocrystal 7G compound. Present study corroborates the pharmacophore-based virtual screening, and finds the compound 6F as a potent Inhibitor of PKC, having therapeutic potential for Alzheimer's disease. Worldwide, 46.8 million people are believed to be living with Alzheimer's disease. When elderly population increases rapidly and neurodegenerative burden also increases in parallel, we project the findings from this study will be useful for drug developing efforts targeting Alzheimer's disease.

Measuring tissue oxygenation

NASA Technical Reports Server (NTRS)

Soyemi, Olusola O. (Inventor); Soller, Babs R. (Inventor); Yang, Ye (Inventor)

2009-01-01

Methods and systems for calculating tissue oxygenation, e.g., oxygen saturation, in a target tissue are disclosed. In some embodiments, the methods include: (a) directing incident radiation to a target tissue and determining reflectance spectra of the target tissue by measuring intensities of reflected radiation from the target tissue at a plurality of radiation wavelengths; (b) correcting the measured intensities of the reflectance spectra to reduce contributions thereto from skin and fat layers through which the incident radiation propagates; (c) determining oxygen saturation in the target tissue based on the corrected reflectance spectra; and (d) outputting the determined value of oxygen saturation.

Targeted Morphoproteomic Profiling of Ewing's Sarcoma Treated with Insulin-Like Growth Factor 1 Receptor (IGF1R) Inhibitors: Response/Resistance Signatures

PubMed Central

Subbiah, Vivek; Naing, Aung; Brown, Robert E.; Chen, Helen; Doyle, Laurence; LoRusso, Patricia; Benjamin, Robert; Anderson, Pete; Kurzrock, Razelle

2011-01-01

Background Insulin-like growth factor 1 receptor (IGF1R) targeted therapies have resulted in responses in a small number of patients with advanced metastatic Ewing's sarcoma. We performed morphoproteomic profiling to better understand response/resistance mechanisms of Ewing's sarcoma to IGF1R inhibitor-based therapy. Methodology/Principal Findings This pilot study assessed two patients with advanced Ewing's sarcoma treated with IGF1R antibody alone followed by combined IGF1R inhibitor plus mammalian target of rapamycin (mTOR) inhibitor treatment once resistance to single-agent IGF1R inhibitor developed. Immunohistochemical probes were applied to detect p-mTOR (Ser2448), p-Akt (Ser473), p-ERK1/2 (Thr202/Tyr204), nestin, and p-STAT3 (Tyr 705) in the original and recurrent tumor. The initial remarkable radiographic responses to IGF1R-antibody therapy was followed by resistance and then response to combined IGF1R plus mTOR inhibitor therapy in both patients, and then resistance to the combination regimen in one patient. In patient 1, upregulation of p-Akt and p-mTOR in the tumor that relapsed after initial response to IGF1R antibody might explain the resistance that developed, and the subsequent response to combined IGF1R plus mTOR inhibitor therapy. In patient 2, upregulation of mTOR was seen in the primary tumor, perhaps explaining the initial response to the IGF1R and mTOR inhibitor combination, while the resistant tumor that emerged showed activation of the ERK pathway as well. Conclusion/Significance Morphoproteomic analysis revealed that the mTOR pathway was activated in these two patients with advanced Ewing's sarcoma who showed response to combined IGF1R and mTOR inhibition, and the ERK pathway in the patient in whom resistance to this combination emerged. Our pilot results suggests that morphoproteomic assessment of signaling pathway activation in Ewing's sarcoma merits further investigation as a guide to understanding response and resistance signatures. PMID

Maintenance of the Extracellular Matrix in Rat Anterior Pituitary Gland: Identification of Cells Expressing Tissue Inhibitors of Metalloproteinases.

PubMed

Azuma, Morio; Tofrizal, Alimuddin; Maliza, Rita; Batchuluun, Khongorzul; Ramadhani, Dini; Syaidah, Rahimi; Tsukada, Takehiro; Fujiwara, Ken; Kikuchi, Motoshi; Horiguchi, Kotaro; Yashiro, Takashi

2015-12-25

The extracellular matrix (ECM) is important in creating cellular environments in tissues. Recent studies have demonstrated that ECM components are localized in anterior pituitary cells and affect cell activity. Thus, clarifying the mechanism responsible for ECM maintenance would improve understanding of gland function. Tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of matrix metalloproteinases and participate in ECM degradation. In this study, we investigated whether cells expressing TIMPs are present in rat anterior pituitary gland. Reverse transcription polymerase chain reaction was used to analyze expression of the TIMP family (TIMP1-4), and cells producing TIMPs in the gland were identified by using in situ hybridization. Expression of TIMP1, TIMP2, and TIMP3 mRNAs was detected, and the TIMP-expressing cells were located in the gland. The TIMP-expressing cells were also investigated by means of double-staining with in situ hybridization and immunohistochemical techniques. Double-staining revealed that TIMP1 mRNA was expressed in folliculostellate cells. TIMP2 mRNA was detected in folliculostellate cells, prolactin cells, and thyroid-stimulating hormone cells. TIMP3 mRNA was identified in endothelial cells, pericytes, novel desmin-immunopositive perivascular cells, and folliculostellate cells. These findings indicate that TIMP1-, TIMP2-, and TIMP3-expressing cells are present in rat anterior pituitary gland and that they are involved in maintaining ECM components.

Maintenance of the Extracellular Matrix in Rat Anterior Pituitary Gland: Identification of Cells Expressing Tissue Inhibitors of Metalloproteinases

PubMed Central

Azuma, Morio; Tofrizal, Alimuddin; Maliza, Rita; Batchuluun, Khongorzul; Ramadhani, Dini; Syaidah, Rahimi; Tsukada, Takehiro; Fujiwara, Ken; Kikuchi, Motoshi; Horiguchi, Kotaro; Yashiro, Takashi

2015-01-01

The extracellular matrix (ECM) is important in creating cellular environments in tissues. Recent studies have demonstrated that ECM components are localized in anterior pituitary cells and affect cell activity. Thus, clarifying the mechanism responsible for ECM maintenance would improve understanding of gland function. Tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of matrix metalloproteinases and participate in ECM degradation. In this study, we investigated whether cells expressing TIMPs are present in rat anterior pituitary gland. Reverse transcription polymerase chain reaction was used to analyze expression of the TIMP family (TIMP1-4), and cells producing TIMPs in the gland were identified by using in situ hybridization. Expression of TIMP1, TIMP2, and TIMP3 mRNAs was detected, and the TIMP-expressing cells were located in the gland. The TIMP-expressing cells were also investigated by means of double-staining with in situ hybridization and immunohistochemical techniques. Double-staining revealed that TIMP1 mRNA was expressed in folliculostellate cells. TIMP2 mRNA was detected in folliculostellate cells, prolactin cells, and thyroid-stimulating hormone cells. TIMP3 mRNA was identified in endothelial cells, pericytes, novel desmin-immunopositive perivascular cells, and folliculostellate cells. These findings indicate that TIMP1-, TIMP2-, and TIMP3-expressing cells are present in rat anterior pituitary gland and that they are involved in maintaining ECM components. PMID:26855451

Network modeling of kinase inhibitor polypharmacology reveals pathways targeted in chemical screens

PubMed Central

Ursu, Oana; Gosline, Sara J. C.; Beeharry, Neil; Fink, Lauren; Bhattacharjee, Vikram; Huang, Shao-shan Carol; Zhou, Yan; Yen, Tim; Fraenkel, Ernest

2017-01-01

Small molecule screens are widely used to prioritize pharmaceutical development. However, determining the pathways targeted by these molecules is challenging, since the compounds are often promiscuous. We present a network strategy that takes into account the polypharmacology of small molecules in order to generate hypotheses for their broader mode of action. We report a screen for kinase inhibitors that increase the efficacy of gemcitabine, the first-line chemotherapy for pancreatic cancer. Eight kinase inhibitors emerge that are known to affect 201 kinases, of which only three kinases have been previously identified as modifiers of gemcitabine toxicity. In this work, we use the SAMNet algorithm to identify pathways linking these kinases and genetic modifiers of gemcitabine toxicity with transcriptional and epigenetic changes induced by gemcitabine that we measure using DNaseI-seq and RNA-seq. SAMNet uses a constrained optimization algorithm to connect genes from these complementary datasets through a small set of protein-protein and protein-DNA interactions. The resulting network recapitulates known pathways including DNA repair, cell proliferation and the epithelial-to-mesenchymal transition. We use the network to predict genes with important roles in the gemcitabine response, including six that have already been shown to modify gemcitabine efficacy in pancreatic cancer and ten novel candidates. Our work reveals the important role of polypharmacology in the activity of these chemosensitizing agents. PMID:29023490

Plasminogen activator inhibitor-1 is an independent prognostic factor of ovarian cancer and IMD-4482, a novel plasminogen activator inhibitor-1 inhibitor, inhibits ovarian cancer peritoneal dissemination

PubMed Central

Nakatsuka, Erika; Sawada, Kenjiro; Nakamura, Koji; Yoshimura, Akihito; Kinose, Yasuto; Kodama, Michiko; Hashimoto, Kae; Mabuchi, Seiji; Makino, Hiroshi; Morii, Eiichi; Yamaguchi, Yoichi; Yanase, Takeshi; Itai, Akiko; Morishige, Ken-ichirou; Kimura, Tadashi

2017-01-01

In the present study, the therapeutic potential of targeting plasminogen activator inhibitor-1 (PAI-1) in ovarian cancer was tested. Tissues samples from 154 cases of ovarian carcinoma were immunostained with anti-PAI-1 antibody, and the prognostic value was analyzed. Among the samples, 67% (104/154) showed strong PAI-1 expression; this was significantly associated with poor prognosis (progression-free survival: 20 vs. 31 months, P = 0.0033). In particular, among patients with stage II-IV serous adenocarcinoma, PAI-1 expression was an independent prognostic factor. The effect of a novel PAI-1 inhibitor, IMD-4482, on ovarian cancer cell lines was assessed and its therapeutic potential was examined using a xenograft mouse model of ovarian cancer. IMD-4482 inhibited in vitro cell adhesion to vitronectin in PAI-1-positive ovarian cancer cells, followed by the inhibition of extracellular signal-regulated kinase and focal adhesion kinase phosphorylation through dissociation of the PAI-urokinase receptor complex from integrin αVβ3. IMD-4482 caused G0/G1 cell arrest and inhibited the proliferation of PAI-1-positive ovarian cancer cells. In the xenograft model, IMD-4482 significantly inhibited peritoneal dissemination with the reduction of PAI-1 expression and the inhibition of focal adhesion kinase phosphorylation. Collectively, the functional inhibition of PAI-1 significantly inhibited ovarian cancer progression, and targeting PAI-1 may be a potential therapeutic strategy in ovarian cancer. PMID:29163796

Visceral adipose tissue macrophage-targeted TACE silencing to treat obesity-induced type 2 diabetes.

PubMed

Yong, Seok-Beom; Song, Yoonsung; Kim, Yong-Hee

2017-12-01

Obesity is an increasingly prevalent global health problem. Due to its close relations with metabolic diseases and cancer, new therapeutic approaches for treating obesity and obesity-induced metabolic diseases are required. Visceral white adipose tissue (WAT) has been closely associated with obesity-induced inflammation and adipose tissue macrophages (ATMs) are responsible for obesity-induced inflammation by releasing inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6. TNF-α converting enzyme (TACE) is a transmembrane enzyme that induces the enzymatic cleavage and release of inflammatory cytokines. In this study, we developed a nonviral gene delivery system consisting of an oligopeptide (ATS-9R) that can selectively target visceral ATMs. In here we shows visceral adipose tissue-dominant inflammatory gene over-expressions in obese mouse and our strategy enabled the preferential delivery of therapeutic genes to visceral ATMs and successfully achieved ATM-targeted gene silencing. Finally, ATS-9R-mediated TACE gene silencing in visceral ATMs alleviated visceral fat inflammation and improved type 2 diabetes by reducing whole body inflammation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Protein digestion in cereal aphids (Sitobion avenae) as a target for plant defence by endogenous proteinase inhibitors.

PubMed

Pyati, Prashant; Bandani, Ali R; Fitches, Elaine; Gatehouse, John A

2011-07-01

Gut extracts from cereal aphids (Sitobion avenae) showed significant levels of proteolytic activity, which was inhibited by reagents specific for cysteine proteases and chymotrypsin-like proteases. Gut tissue contained cDNAs encoding cathepsin B-like cysteine proteinases, similar to those identified in the closely related pea aphid (Acyrthosiphon pisum). Analysis of honeydew (liquid excreta) from cereal aphids fed on diet containing ovalbumin showed that digestion of ingested proteins occurred in vivo. Protein could partially substitute for free amino acids in diet, although it could not support complete development. Recombinant wheat proteinase inhibitors (PIs) fed in diet were antimetabolic to cereal aphids, even when normal levels of free amino acids were present. PIs inhibited proteolysis by aphid gut extracts in vitro, and digestion of protein fed to aphids in vivo. Wheat subtilisin/chymotrypsin inhibitor, which was found to inhibit serine and cysteine proteinases, was more effective in both inhibitory and antimetabolic activity than wheat cystatin, which inhibited cysteine proteases only. Digestion of ingested protein is unlikely to contribute significantly to nutritional requirements when aphids are feeding on phloem, and the antimetabolic activity of dietary proteinase inhibitors is suggested to result from effects on proteinases involved in degradation of endogenous proteins. Copyright © 2011 Elsevier Ltd. All rights reserved.

Evaluation of deoxyhypusine synthase inhibitors targeting BCR-ABL positive leukemias.

PubMed

Ziegler, Patrick; Chahoud, Tuhama; Wilhelm, Thomas; Pällman, Nora; Braig, Melanie; Wiehle, Valeska; Ziegler, Susanne; Schröder, Marcus; Meier, Chris; Kolodzik, Adrian; Rarey, Matthias; Panse, Jens; Hauber, Joachim; Balabanov, Stefan; Brümmendorf, Tim H

2012-12-01

Effective inhibition of BCR-ABL tyrosine kinase activity with Imatinib represents a breakthrough in the treatment of patients with chronic myeloid leukemia (CML). However, more than 30 % of patients with CML in chronic phase do not respond adequately to Imatinib and the drug seems not to affect the quiescent pool of BCR-ABL positive leukemic stem and progenitor cells. Therefore, despite encouraging clinical results, Imatinib can still not be considered a curative treatment option in CML. We recently reported downregulation of eukaryotic initiation factor 5A (eIF5A) in Imatinib treated K562 cells. Furthermore, the inhibition of eIF5A by siRNA in combination with Imatinib has been shown to exert synergistic cytotoxic effects on BCR-ABL positive cell lines. Based on the structure of known deoxyhypusine synthase (DHS) inhibitors such as CNI-1493, a drug design approach was applied to develop potential compounds targeting DHS. Here we report the biological evaluation of selected novel (DHSI-15) as compared to established (CNI-1493, deoxyspergualin) DHS inhibitors. We show that upon the compounds tested, DHSI-15 and deoxyspergualin exert strongest antiproliferative effects on BCR-ABL cells including Imatinib resistant mutants. However, this effect did not seem to be restricted to BCR-ABL positive cell lines or primary cells. Both compounds are able to induce apoptosis/necrosis during long term incubation of BCR-ABL positive BA/F3 derivates. Pharmacological synergism can be observed for deoxyspergualin and Imatinib, but not for DHSI-15 and Imatinib. Finally we show that deoxyspergualin is able to inhibit proliferation of CD34+ progenitor cells from CML patients. We conclude that inhibition of deoxyhypusine synthase (DHS) can be supportive for the anti-proliferative treatment of leukemia and merits further investigation including other cancers.

Recent progress in the development of protein-protein interaction inhibitors targeting androgen receptor-coactivator binding in prostate cancer.

PubMed

Biron, Eric; Bédard, François

2016-07-01

The androgen receptor (AR) is a key regulator for the growth, differentiation and survival of prostate cancer cells. Identified as a primary target for the treatment of prostate cancer, many therapeutic strategies have been developed to attenuate AR signaling in prostate cancer cells. While frontline androgen-deprivation therapies targeting either the production or action of androgens usually yield favorable responses in prostate cancer patients, a significant number acquire treatment resistance. Known as the castration-resistant prostate cancer (CRPC), the treatment options are limited for this advanced stage. It has been shown that AR signaling is restored in CRPC due to many aberrant mechanisms such as AR mutations, amplification or expression of constitutively active splice-variants. Coregulator recruitment is a crucial regulatory step in AR signaling and the direct blockade of coactivator binding to AR offers the opportunity to develop therapeutic agents that would remain effective in prostate cancer cells resistant to conventional endocrine therapies. Structural analyses of the AR have identified key surfaces involved in protein-protein interaction with coregulators that have been recently used to design and develop promising AR-coactivator binding inhibitors. In this review we will discuss the design and development of small-molecule inhibitors targeting the AR-coactivator interactions for the treatment of prostate cancer. Copyright © 2015 Elsevier Ltd. All rights reserved.

Homology modeling and virtual screening to discover potent inhibitors targeting the imidazole glycerophosphate dehydratase protein in Staphylococcus xylosus

NASA Astrophysics Data System (ADS)

Chen, Xing-Ru; Wang, Xiao-Ting; Hao, Mei-Qi; Zhou, Yong-Hui; Cui, Wen-Qiang; Xing, Xiao-Xu; Xu, Chang-Geng; Bai, Jing-Wen; Li, Yan-Hua

2017-11-01

The imidazole glycerophosphate dehydratase (IGPD) protein is a therapeutic target for herbicide discovery. It is also regarded as a possible target in Staphylococcus xylosus (S. xylosus) for solving mastitis in the dairy cow. The 3D structure of IGPD protein is essential for discovering novel inhibitors during high-throughput virtual screening. However, to date, the 3D structure of IGPD protein of S. xylosus has not been solved. In this study, a series of computational techniques including homology modeling, Ramachandran Plots, and Verify 3D were performed in order to construct an appropriate 3D model of IGPD protein of S. xylosus. Nine hits were identified from 2500 compounds by docking studies. Then, these 9 compounds were first tested in vitro in S. xylosus biofilm formation using crystal violet staining. One of the potential compounds, baicalin was shown to significantly inhibit S. xylosus biofilm formation. Finally, the baicalin was further evaluated, which showed better inhibition of biofilm formation capability in S. xylosus by scanning electron microscopy. Hence, we have predicted the structure of IGPD protein of S. xylosus using computational techniques. We further discovered the IGPD protein was targeted by baicalin compound which inhibited the biofilm formation in S. xylosus. Our findings here would provide implications for the further development of novel IGPD inhibitors for the treatment of dairy mastitis.

Homology Modeling and Virtual Screening to Discover Potent Inhibitors Targeting the Imidazole Glycerophosphate Dehydratase Protein in Staphylococcus xylosus.

PubMed

Chen, Xing-Ru; Wang, Xiao-Ting; Hao, Mei-Qi; Zhou, Yong-Hui; Cui, Wen-Qiang; Xing, Xiao-Xu; Xu, Chang-Geng; Bai, Jing-Wen; Li, Yan-Hua

2017-01-01

The imidazole glycerophosphate dehydratase (IGPD) protein is a therapeutic target for herbicide discovery. It is also regarded as a possible target in Staphylococcus xylosus ( S. xylosus ) for solving mastitis in the dairy cow. The 3D structure of IGPD protein is essential for discovering novel inhibitors during high-throughput virtual screening. However, to date, the 3D structure of IGPD protein of S. xylosus has not been solved. In this study, a series of computational techniques including homology modeling, Ramachandran Plots, and Verify 3D were performed in order to construct an appropriate 3D model of IGPD protein of S. xylosus . Nine hits were identified from 2,500 compounds by docking studies. Then, these nine compounds were first tested in vitro in S. xylosus biofilm formation using crystal violet staining. One of the potential compounds, baicalin was shown to significantly inhibit S. xylosus biofilm formation. Finally, the baicalin was further evaluated, which showed better inhibition of biofilm formation capability in S. xylosus by scanning electron microscopy. Hence, we have predicted the structure of IGPD protein of S. xylosus using computational techniques. We further discovered the IGPD protein was targeted by baicalin compound which inhibited the biofilm formation in S. xylosus . Our findings here would provide implications for the further development of novel IGPD inhibitors for the treatment of dairy mastitis.

High-throughput docking for the identification of new influenza A virus polymerase inhibitors targeting the PA-PB1 protein-protein interaction.

PubMed

Tintori, Cristina; Laurenzana, Ilaria; Fallacara, Anna Lucia; Kessler, Ulrich; Pilger, Beatrice; Stergiou, Lilli; Botta, Maurizio

2014-01-01

A high-throughput molecular docking approach was successfully applied for the selection of potential inhibitors of the Influenza RNA-polymerase which act by targeting the PA-PB1 protein-protein interaction. Commercially available compounds were purchased and biologically evaluated in vitro using an ELISA-based assay. As a result, some compounds possessing a 3-cyano-4,6-diphenyl-pyridine nucleus emerged as effective inhibitors with the best ones showing IC50 values in the micromolar range. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of Target Therapy on the Content of Transcription and Growth Factors, Protein Kinase TOR, and Activity of Intracellular Proteases in Patients with Metastatic Renal Cell Carcinoma.

PubMed

Spirina, L V; Usynin, E A; Kondakova, I V; Yurmazov, Z A; Slonimskaya, E M

2016-04-01

We analyzed the dynamics of the expression of transcription factors, VEGF and its receptor VEGFR2, serine-threonine protein kinase mTOR and activity of proteasome and calpain in patients with metastatic renal cancer during therapy with tyrosine kinase inhibitor Votrient and mTOR blocker Afinitor. The expression of hypoxic nuclear factor HIF-1α in the tumor tissue decreased during therapy with the target preparations. The decrease of VEGF and its receptor VEGFR2 was observed only in patients treated with mTOR inhibitor. The increase in calpain activity in the tumor tissue was observed in both groups. These findings extend our understanding of the mechanism of action of target anticancer preparations as allow considering the studied markers as predictors in choosing optimal therapy.

Radiation induced COX-2 expression and mutagenesis at non-targeted lung tissues of gpt delta transgenic mice

PubMed Central

Chai, Y; Calaf, G M; Zhou, H; Ghandhi, S A; Elliston, C D; Wen, G; Nohmi, T; Amundson, S A; Hei, T K

2013-01-01

Background: Although radiation-induced bystander effects have been confirmed using a variety of endpoints, the mechanism(s) underlying these effects are not well understood, especially for in vivo study. Methods: A 1-cm2 area (1 cm × 1 cm) in the lower abdominal region of gpt delta transgenic mice was irradiated with 5 Gy of 300 keV X-rays, and changes in out-of-field lung and liver were observed. Results: Compared with sham-treated controls, the Spi− mutation frequency increased 2.4-fold in non-targeted lung tissues at 24 h after partial body irradiation (PBIR). Consistent with dramatic Cyclooxygenase 2 (COX-2) induction in the non-targeted bronchial epithelial cells, increasing levels of prostaglandin, together with 8-hydroxydeoxyguanosine, in the out-of-field lung tissues were observed after PBIR. In addition, DNA double-strand breaks and apoptosis were induced in bystander lung tissues after PBIR. Conclusion: The PBIR induces DNA damage and mutagenesis in non-targeted lung tissues, especially in bronchial epithelial cells, and COX-2 has an essential role in bystander mutagenesis. PMID:23321513

Anticoagulation by factor Xa inhibitors.

PubMed

Orfeo, T; Butenas, S; Brummel-Ziedins, K E; Gissel, M; Mann, K G

2010-08-01

Therapeutic agents that regulate blood coagulation are critical to the management of thrombotic disorders, with the selective targeting of factor (F) Xa emerging as a promising approach. To assess anticoagulant strategies targeting FXa. A deterministic computational model of tissue factor (Tf)-initiated thrombin generation and two empirical experimental systems (a synthetic coagulation proteome reconstruction using purified proteins and a whole blood model) were used to evaluate clinically relevant examples of the two available types of FXa-directed anticoagulants [an antithrombin (AT)-dependent agent, fondaparinux, and an AT-independent inhibitor, Rivaroxaban] in experimental regimens relevant to long-term (suppression of new Tf-initiated events) and acute (suppression of ongoing coagulation processes) clinical applications. Computational representations of each anticoagulant's efficacy in suppressing thrombin generation over a range of anticoagulant concentrations in both anticoagulation regimens were validated by results from corresponding empirical reconstructions and were consistent with those recommended for long-term and acute clinical applications, respectively. All three model systems suggested that Rivaroxaban would prove more effective in the suppression of an ongoing coagulation process than fondaparinux, reflecting its much higher reactivity toward the prothrombinase complex. The success of fondaparinux in acute settings in vivo is not explained solely by its properties as an FXa inhibitor. We have reported that FIXa contributes to the long-term capacity of clot-associated catalysts to restart a coagulation process, suggesting that the enhanced anti-FIXa activity of fondaparinux-AT may be critical to its success in acute settings in vivo. © 2010 International Society on Thrombosis and Haemostasis.

Extracellular proteases as targets for drug development

PubMed Central

Cudic, Mare

2015-01-01

Proteases constitute one of the primary targets in drug discovery. In the present review, we focus on extracellular proteases (ECPs) because of their differential expression in many pathophysiological processes, including cancer, cardiovascular conditions, and inflammatory, pulmonary, and periodontal diseases. Many new ECP inhibitors are currently under clinical investigation and a significant increase in new therapies based on protease inhibition can be expected in the coming years. In addition to directly blocking the activity of a targeted protease, one can take advantage of differential expression in disease states to selectively deliver therapeutic or imaging agents. Recent studies in targeted drug development for the metalloproteases (matrix metalloproteinases, adamalysins, pappalysins, neprilysin, angiotensin-converting enzyme, metallocarboxypeptidases, and glutamate carboxypeptidase II), serine proteases (elastase, coagulation factors, tissue/urokinase plasminogen activator system, kallikreins, tryptase, dipeptidyl peptidase IV), cysteine proteases (cathepsin B), and renin system are discussed herein. PMID:19689354

3,4-Dimethoxyphenyl bis-benzimidazole, a novel DNA topoisomerase inhibitor that preferentially targets Escherichia coli topoisomerase I

PubMed Central

Bansal, Sandhya; Sinha, Devapriya; Singh, Manish; Cheng, Bokun; Tse-Dinh, Yuk-Ching; Tandon, Vibha

2012-01-01

Objectives Antibiotic resistance in bacterial pathogens is a serious clinical problem. Novel targets are needed to combat increasing drug resistance in Escherichia coli. Our objective is to demonstrate that 2-(3,4-dimethoxyphenyl)-5-[5-(4-methylpiperazin-1-yl)-1H-benzimidazol-2yl]-1H-benzimidazole (DMA) inhibits E. coli DNA topoisomerase I more strongly than human topoisomerase I. In addition, DMA is non-toxic to mammalian cells at antibiotic dosage level. Methods In the present study, we have established DMA as an antibacterial compound by determining MICs, post-antibiotic effects (PAEs) and MBCs for different standard as well as clinical strains of E. coli. We have described the differential catalytic inhibitory mechanism of bis-benzimidazole, DMA, for human and E. coli topoisomerase I and topoisomerase II by performing different assays, including relaxation assays, cleavage–religation assays, DNA unwinding assays, ethidium bromide displacement assays, decatenation assays and DNA gyrase supercoiling assays. Results DMA significantly inhibited bacterial growth at a very low concentration, but did not affect human cell viability at higher concentrations. Activity assays showed that it preferentially targeted E. coli topoisomerase I over human topoisomerase I, topoisomerase II and gyrase. Cleavage–religation assays confirmed DMA as a poison inhibitor of E. coli topoisomerase I. This study illuminates new properties of DMA, which may be further modified to develop an efficient topoisomerase inhibitor that is selective towards bacterial topoisomerase I. Conclusions This is the first report of a bis-benzimidazole acting as an E. coli topoisomerase I inhibitor. DMA is a safe, non-cytotoxic molecule to human cells at concentrations that are needed for antibacterial activity. PMID:22945915

Minireview: The Androgen Receptor in Breast Tissues: Growth Inhibitor, Tumor Suppressor, Oncogene?

PubMed Central

Hickey, T. E.; Robinson, J. L. L.; Carroll, J. S.

2012-01-01

Androgen receptor (AR) signaling exerts an antiestrogenic, growth-inhibitory influence in normal breast tissue, and this role may be sustained in estrogen receptor α (ERα)-positive luminal breast cancers. Conversely, AR signaling may promote growth of a subset of ERα-negative, AR-positive breast cancers with a molecular apocrine phenotype. Understanding the molecular mechanisms whereby androgens can elicit distinct gene expression programs and opposing proliferative responses in these two breast cancer phenotypes is critical to the development of new therapeutic strategies to target the AR in breast cancer. PMID:22745190

Heat-shock protein 27 (HSP27, HSPB1) is up-regulated by MET kinase inhibitors and confers resistance to MET-targeted therapy

PubMed Central

Musiani, Daniele; Konda, John David; Pavan, Simona; Torchiaro, Erica; Sassi, Francesco; Noghero, Alessio; Erriquez, Jessica; Perera, Timothy; Olivero, Martina; Di Renzo, Maria Flavia

2014-01-01

The tyrosine kinase encoded by the MET oncogene is activated by gene mutation or amplification in tumors, which in most instances maintain addiction, i.e., dependency, to MET activation. This makes MET an attractive candidate for targeted therapies. Here we show that, in 3/3 MET-addicted human gastric cancer cell lines, MET kinase inhibition resulted in a 3- to 4-fold increased expression of the antiapoptotic small heat-shock protein of 27 kDa (HSP27, HSPB1). HSP27 increase depended on the inhibition of the MEK/ERK pathway and on heat-shock factor 1 (HSF1) and hypoxia-inducible factor-1α (HIF-1α) regulation. Importantly, HSP27-silenced MET-addicted cells underwent 2- and 3-fold more apoptosis following MET inhibition in vitro and in vivo, respectively. Likewise, in human cancer cells susceptible to epidermal growth factor receptor (EGFR) inhibition, EGFR inhibitors induced HSP27 expression and were strengthened by HSP27 suppression. In control cell lines that were not affected by drugs targeting MET or EGFR, these drugs did not induce HSP27 increase. Therefore, in cancer therapies targeting the MET pathway, the induction of HSP27 might limit the efficacy of anti-MET agents. As HSP27 increase also impairs the effectiveness of EGFR inhibitors and is known to protect cells from chemotherapeutics, the induction of HSP27 by targeted agents might strongly affect the success of combination treatments.—Musiani, D., Konda, J. D., Pavan, S., Torchiaro, E., Sassi, F., Noghero, A., Erriquez, J., Perera, T., Olivero, M., Di Renzo, M. F. Heat-shock protein 27 (HSP27, HSPB1) is up-regulated by MET kinase inhibitors and confers resistance to MET-targeted therapy. PMID:24903273

Chelation: A Fundamental Mechanism of Action of AGE Inhibitors, AGE Breakers, and Other Inhibitors of Diabetes Complications

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

Nagai, Rhoji; Murray, David B.; Metz, Thomas O.

2012-03-01

Advanced glycation or glycoxidation end-products (AGE) increase in tissue proteins with age, and their rate of accumulation is increased in diabetes, nephropathy and inflammatory diseases. AGE inhibitors include a range of compounds that are proposed to act by trapping carbonyl and dicarbonyl intermediates in AGE formation. However, some among the newer generation of AGE inhibitors lack reactive functional groups that would trap reaction intermediates, indicating an alternative mechanism of action. We propose that AGE inhibitors function primarily as chelators, inhibiting metal-catalyzed oxidation reactions. The AGE-inhibitory activity of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers is also consistent with their chelatingmore » activity. Finally, compounds described as AGE breakers, or their hydrolysis products, also have strong chelating activity, suggesting that these compounds also act through their chelating activity. We conclude that chelation is the common, and perhaps the primary, mechanism of action of AGE inhibitors and breakers, and that chronic, mild chelation therapy should prove useful in treatment of diabetes and age-related diseases characterized by oxidative stress, inflammation and increased chemical modification of tissue proteins by advanced glycoxidation and lipoxidation end-products.« less

C-terminal peptides of tissue factor pathway inhibitor are novel host defense molecules.

PubMed

Papareddy, Praveen; Kalle, Martina; Kasetty, Gopinath; Mörgelin, Matthias; Rydengård, Victoria; Albiger, Barbara; Lundqvist, Katarina; Malmsten, Martin; Schmidtchen, Artur

2010-09-03

Tissue factor pathway inhibitor (TFPI) inhibits tissue factor-induced coagulation, but may, via its C terminus, also modulate cell surface, heparin, and lipopolysaccharide interactions as well as participate in growth inhibition. Here we show that C-terminal TFPI peptide sequences are antimicrobial against the gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, gram-positive Bacillus subtilis and Staphylococcus aureus, as well as the fungi Candida albicans and Candida parapsilosis. Fluorescence studies of peptide-treated bacteria, paired with analysis of peptide effects on liposomes, showed that the peptides exerted membrane-breaking effects similar to those seen for the "classic" human antimicrobial peptide LL-37. The killing of E. coli, but not P. aeruginosa, by the C-terminal peptide GGLIKTKRKRKKQRVKIAYEEIFVKNM (GGL27), was enhanced in human plasma and largely abolished in heat-inactivated plasma, a phenomenon linked to generation of antimicrobial C3a and activation of the classic pathway of complement activation. Furthermore, GGL27 displayed anti-endotoxic effects in vitro and in vivo in a mouse model of LPS shock. Importantly, TFPI was found to be expressed in the basal layers of normal epidermis, and was markedly up-regulated in acute skin wounds as well as wound edges of chronic leg ulcers. Furthermore, C-terminal fragments of TFPI were associated with bacteria present in human chronic leg ulcers. These findings suggest a new role for TFPI in cutaneous defense against infections.

Targeted Approaches Applied to Uncommon Diseases: A Case of Salivary Duct Carcinoma Metastatic to the Brain Treated with the Multikinase Inhibitor Neratinib

PubMed Central

Sorenson, Karl R.; Piovezani Ramos, Guilherme; Villasboas Bisneto, Jose Caetano; Price, Katharine

2017-01-01

Salivary duct carcinoma is a rare malignancy associated with hormone receptor and human epidermal growth factor receptor 2 (HER2) overexpression. Local surgical control is the cornerstone of therapy, but a subset of patients develops metastatic disease portending a poor prognosis and limited management options. Intracranial metastases are an uncommon manifestation and present a therapeutic challenge. We report the case of a 31-year-old male who presented with facial pain and swelling subsequently diagnosed with salivary duct carcinoma. Our patient underwent extensive locoregional resection and analysis of the tumor tissue demonstrated evidence of androgen receptor expression and HER2 overexpression. His course was complicated by metastatic extra- and intracranial recurrence despite combined modality treatment with radiation and chemotherapy followed by anti-HER2 monoclonal antibody therapy and androgen deprivation therapy. After exhausting standard treatment options, he received experimental therapy with a new small-molecule tyrosine kinase inhibitor, neratinib, with evidence of a transient clinical response and no significant adverse effects. This case exemplifies the potential and limitations of targeted therapy, particularly when applied to patients with rare diseases and presentations. PMID:28878657

Targeted Approaches Applied to Uncommon Diseases: A Case of Salivary Duct Carcinoma Metastatic to the Brain Treated with the Multikinase Inhibitor Neratinib.

PubMed

Sorenson, Karl R; Piovezani Ramos, Guilherme; Villasboas Bisneto, Jose Caetano; Price, Katharine

2017-01-01

Salivary duct carcinoma is a rare malignancy associated with hormone receptor and human epidermal growth factor receptor 2 (HER2) overexpression. Local surgical control is the cornerstone of therapy, but a subset of patients develops metastatic disease portending a poor prognosis and limited management options. Intracranial metastases are an uncommon manifestation and present a therapeutic challenge. We report the case of a 31-year-old male who presented with facial pain and swelling subsequently diagnosed with salivary duct carcinoma. Our patient underwent extensive locoregional resection and analysis of the tumor tissue demonstrated evidence of androgen receptor expression and HER2 overexpression. His course was complicated by metastatic extra- and intracranial recurrence despite combined modality treatment with radiation and chemotherapy followed by anti-HER2 monoclonal antibody therapy and androgen deprivation therapy. After exhausting standard treatment options, he received experimental therapy with a new small-molecule tyrosine kinase inhibitor, neratinib, with evidence of a transient clinical response and no significant adverse effects. This case exemplifies the potential and limitations of targeted therapy, particularly when applied to patients with rare diseases and presentations.

An integrated approach to identify normal tissue expression of targets for antibody-drug conjugates: case study of TENB2

PubMed Central

Boswell, C Andrew; Mundo, Eduardo E; Firestein, Ron; Zhang, Crystal; Mao, Weiguang; Gill, Herman; Young, Cynthia; Ljumanovic, Nina; Stainton, Shannon; Ulufatu, Sheila; Fourie, Aimee; Kozak, Katherine R; Fuji, Reina; Polakis, Paul; Khawli, Leslie A; Lin, Kedan

2013-01-01

Background and Purpose The success of antibody-drug conjugates (ADCs) depends on the therapeutic window rendered by the differential expression between normal and pathological tissues. The ability to identify and visualize target expression in normal tissues could reveal causes for target-mediated clearance observed in pharmacokinetic characterization. TENB2 is a prostate cancer target associated with the progression of poorly differentiated and androgen-independent tumour types, and ADCs specific for TENB2 are candidate therapeutics. The objective of this study was to locate antigen expression of TENB2 in normal tissues, thereby elucidating the underlying causes of target-mediated clearance. Experimental Approach A series of pharmacokinetics, tissue distribution and mass balance studies were conducted in mice using a radiolabelled anti-TENB2 ADC. These data were complemented by non-invasive single photon emission computed tomography – X-ray computed tomography imaging and immunohistochemistry. Key Results The intestines were identified as a saturable and specific antigen sink that contributes, at least in part, to the rapid target-mediated clearance of the anti-TENB2 antibody and its drug conjugate in rodents. As a proof of concept, we also demonstrated the selective disposition of the ADC in a tumoural environment in vivo using the LuCaP 77 transplant mouse model. High tumour uptake was observed despite the presence of the antigen sink, and antigen specificity was confirmed by antigen blockade. Conclusions and Implications Our findings provide the anatomical location and biological interpretation of target-mediated clearance of anti-TENB2 antibodies and corresponding drug conjugates. Further investigations may be beneficial in addressing the relative contributions to ADC disposition from antigen expression in both normal and pathological tissues. PMID:22889168

An integrated approach to identify normal tissue expression of targets for antibody-drug conjugates: case study of TENB2.

PubMed

Boswell, C Andrew; Mundo, Eduardo E; Firestein, Ron; Zhang, Crystal; Mao, Weiguang; Gill, Herman; Young, Cynthia; Ljumanovic, Nina; Stainton, Shannon; Ulufatu, Sheila; Fourie, Aimee; Kozak, Katherine R; Fuji, Reina; Polakis, Paul; Khawli, Leslie A; Lin, Kedan

2013-01-01

The success of antibody-drug conjugates (ADCs) depends on the therapeutic window rendered by the differential expression between normal and pathological tissues. The ability to identify and visualize target expression in normal tissues could reveal causes for target-mediated clearance observed in pharmacokinetic characterization. TENB2 is a prostate cancer target associated with the progression of poorly differentiated and androgen-independent tumour types, and ADCs specific for TENB2 are candidate therapeutics. The objective of this study was to locate antigen expression of TENB2 in normal tissues, thereby elucidating the underlying causes of target-mediated clearance. A series of pharmacokinetics, tissue distribution and mass balance studies were conducted in mice using a radiolabelled anti-TENB2 ADC. These data were complemented by non-invasive single photon emission computed tomography - X-ray computed tomography imaging and immunohistochemistry. The intestines were identified as a saturable and specific antigen sink that contributes, at least in part, to the rapid target-mediated clearance of the anti-TENB2 antibody and its drug conjugate in rodents. As a proof of concept, we also demonstrated the selective disposition of the ADC in a tumoural environment in vivo using the LuCaP 77 transplant mouse model. High tumour uptake was observed despite the presence of the antigen sink, and antigen specificity was confirmed by antigen blockade. Our findings provide the anatomical location and biological interpretation of target-mediated clearance of anti-TENB2 antibodies and corresponding drug conjugates. Further investigations may be beneficial in addressing the relative contributions to ADC disposition from antigen expression in both normal and pathological tissues. © 2012 Genentech, Inc.. British Journal of Pharmacology © 2012 The British Pharmacological Society.

Synergistic Drug Combinations with a CDK4/6 Inhibitor in T-cell Acute Lymphoblastic Leukemia.

PubMed

Pikman, Yana; Alexe, Gabriela; Roti, Giovanni; Conway, Amy Saur; Furman, Andrew; Lee, Emily S; Place, Andrew E; Kim, Sunkyu; Saran, Chitra; Modiste, Rebecca; Weinstock, David M; Harris, Marian; Kung, Andrew L; Silverman, Lewis B; Stegmaier, Kimberly

2017-02-15

Purpose: Although significant progress has been made in the treatment of T-cell acute lymphoblastic leukemia (T-ALL), many patients will require additional therapy for relapsed/refractory disease. Cyclin D3 (CCND3) and CDK6 are highly expressed in T-ALL and have been effectively targeted in mutant NOTCH1-driven mouse models of this disease with a CDK4/6 small-molecule inhibitor. Combination therapy, however, will be needed for the successful treatment of human disease. Experimental Design: We performed preclinical drug testing using a panel of T-ALL cell lines first with LEE011, a CDK4/6 inhibitor, and next with the combination of LEE011 with a panel of drugs relevant to T-ALL treatment. We then tested the combination of LEE011 with dexamethasone or everolimus in three orthotopic mouse models and measured on-target drug activity. Results: We first determined that both NOTCH1 -mutant and wild-type T-ALL are highly sensitive to pharmacologic inhibition of CDK4/6 when wild-type RB is expressed. Next, we determined that CDK4/6 inhibitors are antagonistic when used either concurrently or in sequence with many of the drugs used to treat relapsed T-ALL (methotrexate, mercaptopurine, asparaginase, and doxorubicin) but are synergistic with glucocorticoids, an mTOR inhibitor, and gamma secretase inhibitor. The combinations of LEE011 with the glucocorticoid dexamethasone or the mTOR inhibitor everolimus were tested in vivo and prolonged survival in three orthotopic mouse models of T-ALL. On-target activity was measured in peripheral blood and tissue of treated mice. Conclusions: We conclude that LEE011 is active in T-ALL and that combination therapy with corticosteroids and/or mTOR inhibitors warrants further investigation. Clin Cancer Res; 23(4); 1012-24. ©2016 AACR See related commentary by Carroll et al., p. 873 . ©2016 American Association for Cancer Research.

New conceptual method for directly cooling the target biological tissues

NASA Astrophysics Data System (ADS)

Ji, Yan; Liu, Jing

2005-01-01

Hypothermia is a commonly adopted strategy to decrease the cerebral oxygen demands, which is critical for the patient to sustain longer time when subjected to a hypoxia. However, when circulatory arrest occurs, the traditional approaches such as selective brain cooling (SBC), systemic body cooling or perfusing cool blood are often not very helpful due to their slow cooling rates in preventing the tendency of a slight cerebral temperature increase at the onset of circulatory arrest. To resolve such difficult issue, a new conceptual volumetric cooling method (VCM) through minimally invasive injection of physiological coolant was proposed in this study. A heat and fluid transport model based on porous medium configuration was established to describe the thermal responses of brain tissues during hypothermia resuscitation. Theoretical calculations indicated that VCM could significantly improve the cooling rate in the deep part of the biological tissues within a desired period of time. To further test this approach, a series of either in vitro or in vivo animal experiments were performed, which also strongly supported the theoretical predictions and indicated that VCM was well appropriate for the localized cooling of target tissues. The concept of the present VCM could also possibly be extended to more wide clinical situations, when an instant and highly localized cooling for the specific organs or tissues are urgently requested. It also raised challenging issues such as injury or negative effect for the clinical operation of this VCM, which need to be addressed in the coming study.

Discovering Anti-platelet Drug Combinations with an Integrated Model of Activator-Inhibitor Relationships, Activator-Activator Synergies and Inhibitor-Inhibitor Synergies

PubMed Central

Lombardi, Federica; Golla, Kalyan; Fitzpatrick, Darren J.; Casey, Fergal P.; Moran, Niamh; Shields, Denis C.

2015-01-01

Identifying effective therapeutic drug combinations that modulate complex signaling pathways in platelets is central to the advancement of effective anti-thrombotic therapies. However, there is no systems model of the platelet that predicts responses to different inhibitor combinations. We developed an approach which goes beyond current inhibitor-inhibitor combination screening to efficiently consider other signaling aspects that may give insights into the behaviour of the platelet as a system. We investigated combinations of platelet inhibitors and activators. We evaluated three distinct strands of information, namely: activator-inhibitor combination screens (testing a panel of inhibitors against a panel of activators); inhibitor-inhibitor synergy screens; and activator-activator synergy screens. We demonstrated how these analyses may be efficiently performed, both experimentally and computationally, to identify particular combinations of most interest. Robust tests of activator-activator synergy and of inhibitor-inhibitor synergy required combinations to show significant excesses over the double doses of each component. Modeling identified multiple effects of an inhibitor of the P2Y12 ADP receptor, and complementarity between inhibitor-inhibitor synergy effects and activator-inhibitor combination effects. This approach accelerates the mapping of combination effects of compounds to develop combinations that may be therapeutically beneficial. We integrated the three information sources into a unified model that predicted the benefits of a triple drug combination targeting ADP, thromboxane and thrombin signaling. PMID:25875950

Identification of novel targets for PGC-1{alpha} and histone deacetylase inhibitors in neuroblastoma cells

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

Cowell, Rita M.; Department of Neurology, University of Michigan, Ann Arbor, MI 48109; Talati, Pratik

2009-02-06

Recent evidence suggests that the transcriptional coactivator peroxisome proliferator activated receptor {gamma} coactivator 1{alpha} (PGC-1{alpha}) is involved in the pathology of Huntington's Disease (HD). While animals lacking PGC-1{alpha} express lower levels of genes involved in antioxidant defense and oxidative phosphorylation in the brain, little is known about other targets for PGC-1{alpha} in neuronal cells and whether there are ways to pharmacologically target PGC-1{alpha} in neurons. Here, PGC-1{alpha} overexpression in SH-SY5Y neuroblastoma cells upregulated expression of genes involved in mitochondrial function, glucose transport, fatty acid metabolism, and synaptic function. Overexpression also decreased vulnerability to hydrogen peroxide-induced cell death and caspase 3more » activation. Treatment of cells with the histone deacetylase inhibitors (HDACi's) trichostatin A and valproic acid upregulated PGC-1{alpha} and glucose transporter 4 (GLUT4). These results suggest that PGC-1{alpha} regulates multiple pathways in neurons and that HDACi's may be good candidates to target PGC-1{alpha} and GLUT4 in HD and other neurological disorders.« less

Identification of regulatory targets of tissue-specific transcription factors: application to retina-specific gene regulation

PubMed Central

Qian, Jiang; Esumi, Noriko; Chen, Yangjian; Wang, Qingliang; Chowers, Itay; Zack, Donald J.

2005-01-01

Identification of tissue-specific gene regulatory networks can yield insights into the molecular basis of a tissue's development, function and pathology. Here, we present a computational approach designed to identify potential regulatory target genes of photoreceptor cell-specific transcription factors (TFs). The approach is based on the hypothesis that genes related to the retina in terms of expression, disease and/or function are more likely to be the targets of retina-specific TFs than other genes. A list of genes that are preferentially expressed in retina was obtained by integrating expressed sequence tag, SAGE and microarray datasets. The regulatory targets of retina-specific TFs are enriched in this set of retina-related genes. A Bayesian approach was employed to integrate information about binding site location relative to a gene's transcription start site. Our method was applied to three retina-specific TFs, CRX, NRL and NR2E3, and a number of potential targets were predicted. To experimentally assess the validity of the bioinformatic predictions, mobility shift, transient transfection and chromatin immunoprecipitation assays were performed with five predicted CRX targets, and the results were suggestive of CRX regulation in 5/5, 3/5 and 4/5 cases, respectively. Together, these experiments strongly suggest that RP1, GUCY2D, ABCA4 are novel targets of CRX. PMID:15967807

Tissue factor pathway inhibitor-2: a novel gene involved in zebrafish central nervous system development.

PubMed

Zhang, Yanli; Wang, Lina; Zhou, Wenhao; Wang, Huijun; Zhang, Jin; Deng, Shanshan; Li, Weihua; Li, Huawei; Mao, Zuohua; Ma, Duan

2013-09-01

Tissue factor pathway inhibitor-2 (Tfpi-2) is an important serine protease inhibitor in the extracellular matrix (ECM), but its precise physiological significance remains unknown. This work is part of a series of studies intended to investigate functional roles of Tfpi-2 and explore the underlying molecular mechanisms. First, we cloned and identified zebrafish Tfpi-2 (zTfpi-2) as an evolutionarily conserved protein essential for zebrafish development. We also demonstrated that ztfpi-2 is mainly expressed in the central nervous system (CNS) of zebrafish, and embryonic depletion of ztfpi-2 caused severe CNS defects. In addition, changes of neural markers, including pax2a, egr2b, huC, ngn1, gfap and olig2, confirmed the presence of developmental abnormalities in the relevant regions of ztfpi-2 morphants. Using microarray analysis, we found that members of the Notch pathway, especially her4 and mib, which mediate lateral inhibition in CNS development, were also downregulated. Intriguingly, both her4 and mib were able to partially rescue the ztfpi-2 morphant phenotype. Furthermore, Morpholino knockdown of ztfpi-2 resulted in upregulation of neuronal markers while downregulation of glial markers, providing evidence that the Notch pathway is probably involved in ztfpi-2-mediated CNS development. Copyright © 2013 Elsevier Inc. All rights reserved.

TIL-type protease inhibitors may be used as targeted resistance factors to enhance silkworm defenses against invasive fungi.

PubMed

Li, Youshan; Zhao, Ping; Liu, Huawei; Guo, Xiaomeng; He, Huawei; Zhu, Rui; Xiang, Zhonghuai; Xia, Qingyou

2015-02-01

Entomopathogenic fungi penetrate the insect cuticle using their abundant hydrolases. These hydrolases, which include cuticle-degrading proteases and chitinases, are important virulence factors. Our recent findings suggest that many serine protease inhibitors, especially TIL-type protease inhibitors, are involved in insect resistance to pathogenic microorganisms. To clarify the molecular mechanism underlying this resistance to entomopathogenic fungi and identify novel genes to improve the silkworm antifungal capacity, we conducted an in-depth study of serine protease inhibitors. Here, we cloned and expressed a novel silkworm TIL-type protease inhibitor, BmSPI39. In activity assays, BmSPI39 potently inhibited the virulence protease CDEP-1 of Beauveria bassiana, suggesting that it might suppress the fungal penetration of the silkworm integument by inhibiting the cuticle-degrading proteases secreted by the fungus. Phenol oxidase activation studies showed that melanization is involved in the insect immune response to fungal invasion, and that fungus-induced excessive melanization is suppressed by BmSPI39 by inhibiting the fungal cuticle-degrading proteases. To better understand the mechanism involved in the inhibition of fungal virulence by protease inhibitors, their effects on the germination of B. bassiana conidia was examined. BmSPI38 and BmSPI39 significantly inhibited the germination of B. bassiana conidia. Survival assays showed that BmSPI38 and BmSPI39 markedly improved the survival rates of silkworms, and can therefore be used as targeted resistance proteins in the silkworm. These results provided new insight into the molecular mechanisms whereby insect protease inhibitors confer resistance against entomopathogenic fungi, suggesting their potential application in medicinal or agricultural fields. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthetic inhibitors of bacterial cell division targeting the GTP-binding site of FtsZ.

PubMed

Ruiz-Avila, Laura B; Huecas, Sonia; Artola, Marta; Vergoñós, Albert; Ramírez-Aportela, Erney; Cercenado, Emilia; Barasoain, Isabel; Vázquez-Villa, Henar; Martín-Fontecha, Mar; Chacón, Pablo; López-Rodríguez, María L; Andreu, José M

2013-09-20

Cell division protein FtsZ is the organizer of the cytokinetic Z-ring in most bacteria and a target for new antibiotics. FtsZ assembles with GTP into filaments that hydrolyze the nucleotide at the association interface between monomers and then disassemble. We have replaced FtsZ's GTP with non-nucleotide synthetic inhibitors of bacterial division. We searched for these small molecules among compounds from the literature, from virtual screening (VS), and from our in-house synthetic library (UCM), employing a fluorescence anisotropy primary assay. From these screens we have identified the polyhydroxy aromatic compound UCM05 and its simplified analogue UCM44 that specifically bind to Bacillus subtilis FtsZ monomers with micromolar affinities and perturb normal assembly, as examined with light scattering, polymer sedimentation, and negative stain electron microscopy. On the other hand, these ligands induce the cooperative assembly of nucleotide-devoid archaeal FtsZ into distinct well-ordered polymers, different from GTP-induced filaments. These FtsZ inhibitors impair localization of FtsZ into the Z-ring and inhibit bacterial cell division. The chlorinated analogue UCM53 inhibits the growth of clinical isolates of antibiotic-resistant Staphylococcus aureus and Enterococcus faecalis. We suggest that these interfacial inhibitors recapitulate binding and some assembly-inducing effects of GTP but impair the correct structural dynamics of FtsZ filaments and thus inhibit bacterial division, possibly by binding to a small fraction of the FtsZ molecules in a bacterial cell, which opens a new approach to FtsZ-based antibacterial drug discovery.

Distribution of O-Acetylated Sialic Acids among Target Host Tissues for Influenza Virus

PubMed Central

Barnard, Karen N.; Ossiboff, Robert J.; Khedri, Zahra; Feng, Kurtis H.; Yu, Hai; Chen, Xi; Varki, Ajit

2017-01-01

ABSTRACT Sialic acids (Sias) are important glycans displayed on the cells and tissues of many different animals and are frequent targets for binding and modification by pathogens, including influenza viruses. Influenza virus hemagglutinins bind Sias during the infection of their normal hosts, while the encoded neuraminidases and/or esterases remove or modify the Sia to allow virion release or to prevent rebinding. Sias naturally occur in a variety of modified forms, and modified Sias can alter influenza virus host tropisms through their altered interactions with the viral glycoproteins. However, the distribution of modified Sia forms and their effects on pathogen-host interactions are still poorly understood. Here we used probes developed from viral Sia-binding proteins to detect O-acetylated (4-O-acetyl, 9-O-acetyl, and 7,9-O-acetyl) Sias displayed on the tissues of some natural or experimental hosts for influenza viruses. These modified Sias showed highly variable displays between the hosts and tissues examined. The 9-O-acetyl (and 7,9-) modified Sia forms were found on cells and tissues of many hosts, including mice, humans, ferrets, guinea pigs, pigs, horses, dogs, as well as in those of ducks and embryonated chicken egg tissues and membranes, although in variable amounts. The 4-O-acetyl Sias were found in the respiratory tissues of fewer animals, being primarily displayed in the horse and guinea pig, but were not detected in humans or pigs. The results suggest that these Sia variants may influence virus tropisms by altering and selecting their cell interactions. IMPORTANCE Sialic acids (Sias) are key glycans that control or modulate many normal cell and tissue functions while also interacting with a variety of pathogens, including many different viruses. Sias are naturally displayed in a variety of different forms, with modifications at several positions that can alter their functional interactions with pathogens. In addition, Sias are often modified or

Brassicaceae tissues as inhibitors of nitrification in soil.

PubMed

Brown, Paul D; Morra, Matthew J

2009-09-09

Brassicaceae crops often produce an unexplained increase in plant-available soil N possibly related to bioactive compounds produced from glucosinolates present in the tissues. Our objective was to determine if glucosinolate-containing tissues inhibit nitrification, thereby potentially explaining this observation. Ammonium, NO(2)(-), and NO(3)(-) N were measured in soils amended with Brassicaceae ( Isatis tinctoria L., Brassica napus L., Brassica juncea L., and Sinapis alba L.) tissues containing different glucosinolate types and concentrations or Kentucky bluegrass ( Poa pratensis L.) residues with equivalent C/N ratios as the Brassicaceae samples. There was greater accumulation of NH(4)(+) N in soils amended with tissues containing high glucosinolate concentrations as compared to soils amended with tissues containing no or low glucosinolate concentrations. Nitrite N was detected only in soils amended with Brassicaceae tissues having the highest glucosinolate concentrations. The positive correlation of both NH(4)(+) and NO(2)(-) N accumulation with the glucosinolate concentration indicates the participation of glucosinolate hydrolysis products in nitrification inhibition.

Description of the EuroTARGET cohort: A European collaborative project on TArgeted therapy in renal cell cancer-GEnetic- and tumor-related biomarkers for response and toxicity.

PubMed

van der Zanden, Loes F M; Vermeulen, Sita H; Oskarsdottir, Arna; Maurits, Jake S F; Diekstra, Meta H M; Ambert, Valentin; Cambon-Thomsen, Anne; Castellano, Daniel; Fritsch, Achim; Garcia Donas, Jesus; Guarch Troyas, Rosa; Guchelaar, Henk-Jan; Hartmann, Arndt; Hulsbergen-van de Kaa, Christina; Jaehde, Ulrich; Junker, Kerstin; Martinez-Cardus, Anna; Masson, Gisli; Oosterwijk-Wakka, Jeannette; Radu, Marius T; Rafnar, Thorunn; Rodriguez-Antona, Cristina; Roessler, Max; Ruijtenbeek, Rob; Stefansson, Kari; Warren, Anne; Wessels, Lodewyk; Eisen, Tim; Kiemeney, Lambertus A L M; Oosterwijk, Egbert

2017-08-01

For patients with metastatic renal cell cancer (mRCC), treatment choice is mainly based on clinical parameters. With many treatments available and the limited response to treatment and associated toxicities, there is much interest in identifying better biomarkers for personalized treatment. EuroTARGET aims to identify and characterize host- and tumor-related biomarkers for prediction of response to tyrosine kinase inhibitor therapy in mRCC. Here, we describe the EuroTARGET mRCC patient cohort. EuroTARGET is a European collaborative project designed as an observational study for which patients with mRCC were recruited prospectively in 62 centers. In addition, 462 patients with mRCC from previous studies were included. Detailed clinical information (baseline and follow-up) from all patients was entered in web-based case record forms. Blood was collected for germline DNA and pharmacokinetic/pharmacodynamic analyses and, where available, fresh-frozen tumor material was collected to perform tumor DNA, RNA, kinome, and methylome analyses. In total, 1,210 patients with mRCC were included. Of these, 920 received a tyrosine kinase inhibitor as first-line targeted treatment (sunitinib [N = 713, 78%], sorafenib [N = 41, 4%], or pazopanib [N = 166, 18%]) and had at least 6 months of outcome assessment (median follow-up 15.3 months [interquartile range: 8.5-30.2 months]). Germline DNA samples were available from 824 of these patients, fresh-frozen tumor material from 142 patients, fresh-frozen normal kidney tissue from 95 patients, and tissue microarrays created from formalin-fixed paraffin-embedded tumor material from 247 patients. Of the 920 patients, germline DNA variant chip data were successfully generated for 811 patients (Illumina HumanOmniExpress BeadChip). For 80 patients, next-generation exome sequencing of germline and tumor DNA was performed, tumor RNA sequencing was performed for 124 patients, kinome activity measured and processed for 121 patients (PamChip), and

Discovery of small molecule inhibitors of the Wnt/β-catenin signaling pathway by targeting β-catenin/Tcf4 interactions.

PubMed

Yan, Maocai; Li, Guanqun; An, Jing

2017-06-01

The Wnt/β-catenin signaling pathway typically shows aberrant activation in various cancer cells, especially colorectal cancer cells. This signaling pathway regulates the expression of a variety of tumor-related proteins, including c-myc and cyclin D1, and plays essential roles in tumorigenesis and in the development of many cancers. Small molecules that block the interactions between β-catenin and Tcf4, a downstream stage of activation of the Wnt/β-catenin signaling pathway, could efficiently cut off this signal transduction and thereby act as a novel class of anticancer drugs. This paper reviews the currently reported inhibitors that target β-catenin/Tcf4 interactions, focusing on the discovery approaches taken in the design of these inhibitors and their bioactivities. A brief perspective is then shared on the future discovery and development of this class of inhibitors. Impact statement This mini-review summarized the current knowledge of inhibitors of interactions of beta-catenin/Tcf4 published to date according to their discovery approaches, and discussed their in vitro and in vivo activities, selectivities, and pharmacokinetic properties. Several reviews presently available now in this field describe modulators of the Wnt/beta-catenin pathway, but are generally focused on the bioactivities of these inhibitors. By contrast, this review focused on the drug discovery approaches taken in identifying these types of inhibitors and provided our perspective on further strategies for future drug discoveries. This review also integrated many recently published and important works on highly selective inhibitors as well as rational drug design. We believe that the findings and strategies summarized in this review have broad implications and will be of interest throughout the biochemical and pharmaceutical research community.

Ceramides: a potential therapeutic target in pulmonary emphysema.

PubMed

Tibboel, Jeroen; Reiss, Irwin; de Jongste, Johan C; Post, Martin

2013-10-01

The aim of this manuscript was to characterize airway ceramide profiles in a rodent model of elastase-induced emphysema and to examine the effect of pharmacological intervention directed towards ceramide metabolism. Adult mice were anesthetized and treated with an intratracheal instillation of elastase. Lung function was measured, broncho-alveolar lavage fluid collected and histological and morphometrical analysis of lung tissue performed within 3 weeks after elastase injection, with and without sphingomyelinase inhibitors or serine palmitoyltransferase inhibitor. Ceramides in broncho-alveolar lavage (BAL) fluid were quantified by tandem mass spectrometry. BAL fluid showed a transient increase in total protein and IgM, and activated macrophages and neutrophils. Ceramides were transiently upregulated at day 2 after elastase treatment. Histology showed persistent patchy alveolar destruction at day 2 after elastase installation. Acid and neutral sphingomyelinase inhibitors had no effect on BAL ceramide levels, lung function or histology. Addition of a serine palmitoyltransferase inhibitor ameliorated lung function changes and reduced ceramides in BAL. Ceramides were increased during the acute inflammatory phase of elastase-induced lung injury. Since addition of a serine palmitoyltransferase inhibitor diminished the rise in ceramides and ameliorated lung function, ceramides likely contributed to the early phase of alveolar destruction and are a potential therapeutic target in the elastase model of lung emphysema.

Resistance to AHAS inhibitor herbicides: current understanding.

PubMed

Yu, Qin; Powles, Stephen B

2014-09-01

Acetohydroxyacid synthase (AHAS) inhibitor herbicides currently comprise the largest site-of-action group (with 54 active ingredients across five chemical groups) and have been widely used in world agriculture since they were first introduced in 1982. Resistance evolution in weeds to AHAS inhibitors has been rapid and identified in populations of many weed species. Often, evolved resistance is associated with point mutations in the target AHAS gene; however non-target-site enhanced herbicide metabolism occurs as well. Many AHAS gene resistance mutations can occur and be rapidly enriched owing to a high initial resistance gene frequency, simple and dominant genetic inheritance and lack of major fitness cost of the resistance alleles. Major advances in the elucidation of the crystal structure of the AHAS (Arabidopsis thaliana) catalytic subunit in complex with various AHAS inhibitor herbicides have greatly improved current understanding of the detailed molecular interactions between AHAS, cofactors and herbicides. Compared with target-site resistance, non-target-site resistance to AHAS inhibitor herbicides is less studied and hence less understood. In a few well-studied cases, non-target-site resistance is due to enhanced rates of herbicide metabolism (metabolic resistance), mimicking that occurring in tolerant crop species and often involving cytochrome P450 monooxygenases. However, the specific herbicide-metabolising, resistance-endowing genes are yet to be identified in resistant weed species. The current state of mechanistic understanding of AHAS inhibitor herbicide resistance is reviewed, and outstanding research issues are outlined. © 2013 Society of Chemical Industry.

Gibberellin inhibitors improve embryogenic tissue initiation in conifers.

PubMed

Pullman, Gerald S; Mein, J; Johnson, S; Zhang, Y

2005-02-01

Somatic embryogenesis (SE), the most promising technology to multiply high-value coniferous trees from advanced breeding and genetic engineering programs, is expected to play an important role in increasing productivity, sustainability, and uniformity of future forests in the United States. For commercial use, SE technology must work with a variety of genetically diverse trees. Initiation in loblolly pine (LP; Pinus taeda L.), our main focus species, is often recalcitrant for desirable genotypes. Initiation of LP, slash pine (SP; Pinus elliottii), Douglas-fir (DF; Pseudotsuga menziesii), and Norway spruce (NS; Picea abies) were improved through the use of paclobutrazol, a gibberellin synthesis inhibitor. Paclobutrazol was effective at concentrations ranging from 0.25 mg/l to 3.0 mg/l (0.85-10.2 microM) and optimal in LP at 1.0 mg/l. Using control media (no paclobutrazol) and 0.33-1.0 mg/l paclobutrazol, initiation percentages in LP, SP, DF, and NS were improved from 37.7% to 44.2% (across experiments), 19.3% to 28.5%, 16.9% to 23.7%, and 38.8% to 48.5%, respectively. Other gibberellin inhibitors such as flurprimidol, chlormequat-Cl, and daminozide also caused statistically significant increases in LP initiation when added to the medium at concentrations of 0.34, 10.0, and 1.0 microM, respectively. No detrimental effects on subsequent embryo development were observed when 29 new initiations from medium without GA inhibitor and 28 new initiations from medium containing paclobutrazol were tracked through culture capture, liquid culture establishment, cotyledonary embryo development, and germination.

Crustacean hyperglycemic hormone (CHH) neuropeptidesfamily: Functions, titer, and binding to target tissues.

PubMed

Chung, J Sook; Zmora, N; Katayama, H; Tsutsui, N

2010-05-01

The removal of the eyestalk (s) induces molting and reproduction promoted the presence of regulatory substances in the eyestalk (ES), particularly medulla terminalis X-organ and the sinus gland (MTXO-SG). The PCR-based cloning strategies have allowed for isolating a great number of cDNAs sequences of crustacean hyperglycemic hormone (CHH) neuropeptides family from the eyestalk and non-eyestalk tissues, e.g., pericardial organs and fore- and hindguts. However, the translated corresponding neuropeptides in these tissues, their circulating concentrations, the mode of actions, and specific physiological functions have not been well described. The profiles of CHH neuropeptides present in the MTXO-SG may differ among decapod crustacean species, but they can be largely divided into two sub-groups on the basis of structural homology: (1) CHH and (2) molt-inhibiting hormone (MIH)/mandibular organ-inhibiting hormone (MOIH)/vitellogenesis/gonad-inhibiting hormone (V/GIH). CHH typically elevating the level of circulating glucose from animals under stressful conditions (hyper- and hypothermia, hypoxia, and low salinity) has multiple target tissues and functions such as ecdysteroidogenesis, osmoregulation, and vitellogenesis. Recently, MIH, known for exclusively suppressing ecdysteroidogenesis in Y-organs, is also reported to have an additional role in vitellogenesis of adult female crustacean species, suggesting that some CHH neuropeptides may acquire an extra regulatory role in reproduction at adult stage. This paper reviews the regulatory roles of CHH and MIH at the levels of specific functions, temporal and spatial expression, titers, their binding sites on the target tissues, and second messengers from two crab species: the blue crab, Callinectes sapidus, and the European green crab, Carcinus maenas. It further discusses the diverse regulatory roles of these neuropeptides and the functional plasticity of these neuropeptides in regard to life stage and species

Survivin inhibitor YM155 suppresses gastric cancer xenograft growth in mice without affecting normal tissues.

PubMed

Cheng, Xiao Jiao; Lin, Jia Cheng; Ding, Yan Fei; Zhu, Liming; Ye, Jing; Tu, Shui Ping

2016-02-09

Survivin overexpression is associated with poor prognosis of human gastric cancer, and is a target for gastric cancer therapy. YM155 is originally identified as a specific inhibitor of survivin. In this study, we investigated the antitumor effect of YM155 on human gastric cancer. Our results showed that YM155 treatment significantly inhibited cell proliferation, reduced colony formation and induced apoptosis of gastric cancer cells in a dose-dependent manner. Accordingly, YM155 treatment significantly decreased survivin expression without affecting XIAP expression and increased the cleavage of apoptosis-associated proteins caspase 3, 7, 8, 9. YM155 significantly inhibited sphere formation of gastric cancer cells, suppressed expansion and growth of the formed spheres (cancer stem cell-like cells, CSCs) and downregulated the protein levels of β-catenin, c-Myc, Cyclin D1 and CD44 in gastric cancer cells. YM155 infusion at 5 mg/kg/day for 7 days markedly inhibited growth of gastric cancer xenograft in a nude mouse model. Immunohistochemistry staining and Western Blot showed that YM155 treatment inhibited expression of survivin and CD44, induced apoptosis and reduced CD44+ CSCs in xenograft tumor tissues in vivo. No obvious pathological changes were observed in organs (e.g. heart, liver, lung and kidney) in YM155-treated mice. Our results demonstrated that YM155 inhibits cell proliferation, induces cell apoptosis, reduces cancer stem cell expansion, and inhibits xenograft tumor growth in gastric cancer cells. Our results elucidate a new mechanism by which YM155 inhibits gastric cancer growth by inhibition of CSCs. YM155 may be a promising agent for gastric cancer treatment.

Development of Amidine-Based Sphingosine Kinase 1 Nanomolar Inhibitors and Reduction of Sphingosine 1-Phosphate in Human Leukemia Cells

PubMed Central

Kennedy, Andrew J.; Mathews, Thomas P.; Kharel, Yugesh; Field, Saundra D.; Moyer, Morgan L.; East, James E.; Houck, Joseph D.; Lynch, Kevin R.; Macdonald, Timothy L.

2011-01-01

Sphingosine 1-phosphate (S1P) is a bioactive lipid that has been identified as an accelerant of cancer progression. The sphingosine kinases (SphKs) are the sole producers of S1P and thus SphK inhibitors may prove effective in cancer mitigation and chemosensitization. Of the two SphKs, SphK1 overexpression has been observed in a myriad of cancer cell lines and tissues, and has been recognized as the presumptive target over that of the poorly characterized SphK2. Herein, we present the design and synthesis of amidine-based nanomolar SphK1 subtype-selective inhibitors. A homology model of SphK1, trained with this library of amidine inhibitors, was then used to predict the activity of additional, more potent, inhibitors. Lastly, select amidine inhibitors were validated in human leukemia U937 cells, where they significantly reduced endogenous S1P levels at nanomolar concentrations. PMID:21495716

A liquid chromatography-tandem mass spectrometry-based targeted proteomics assay for monitoring P-glycoprotein levels in human breast tissue.

PubMed

Yang, Ting; Chen, Fei; Xu, Feifei; Wang, Fengliang; Xu, Qingqing; Chen, Yun

2014-09-25

P-glycoprotein (P-gp) can efflux drugs from cancer cells, and its overexpression is commonly associated with multi-drug resistance (MDR). Thus, the accurate quantification of P-gp would help predict the response to chemotherapy and for prognosis of breast cancer patients. An advanced liquid chromatography-tandem mass spectrometry (LC/MS/MS)-based targeted proteomics assay was developed and validated for monitoring P-gp levels in breast tissue. Tryptic peptide 368IIDNKPSIDSYSK380 was selected as a surrogate analyte for quantification, and immuno-depleted tissue extract was used as a surrogate matrix. Matched pairs of breast tissue samples from 60 patients who were suspected to have drug resistance were subject to analysis. The levels of P-gp were quantified. Using data from normal tissue, we suggested a P-gp reference interval. The experimental values of tumor tissue samples were compared with those obtained from Western blotting and immunohistochemistry (IHC). The result indicated that the targeted proteomics approach was comparable to IHC but provided a lower limit of quantification (LOQ) and could afford more reliable results at low concentrations than the other two methods. LC/MS/MS-based targeted proteomics may allow the quantification of P-gp in breast tissue in a more accurate manner. Copyright © 2014 Elsevier B.V. All rights reserved.

Structure-Guided Strategy for the Development of Potent Bivalent ERK Inhibitors

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

Lechtenberg, Bernhard C.; Mace, Peter D.; Sessions, E. Hampton

ERK is the effector kinase of the RAS-RAF-MEK-ERK signaling cascade, which promotes cell transformation and malignancy in many cancers and is thus a major drug target in oncology. Kinase inhibitors targeting RAF or MEK are already used for the treatment of certain cancers, such as melanoma. Although the initial response to these drugs can be dramatic, development of drug resistance is a major challenge, even with combination therapies targeting both RAF and MEK. Importantly, most resistance mechanisms still rely on activation of the downstream effector kinase ERK, making it a promising target for drug development efforts. Here, we report themore » design and structural/functional characterization of a set of bivalent ERK inhibitors that combine a small molecule inhibitor that binds to the ATP-binding pocket with a peptide that selectively binds to an ERK protein interaction surface, the D-site recruitment site (DRS). Our studies show that the lead bivalent inhibitor, SBP3, has markedly improved potency compared to the small molecule inhibitor alone. Unexpectedly, we found that SBP3 also binds to several ERK-related kinases that contain a DRS, highlighting the importance of experimentally verifying the predicted specificity of bivalent inhibitors. However, SBP3 does not target any other kinases belonging to the same CMGC branch of the kinome. Additionally, our modular click chemistry inhibitor design facilitates the generation of different combinations of small molecule inhibitors with ERK-targeting peptides.« less

Tissue inhibitor of metalloproteinase-2(TIMP-2)-deficient mice display motor deficits.

PubMed

Jaworski, Diane M; Soloway, Paul; Caterina, John; Falls, William A

2006-01-01

The degradation of the extracellular matrix is regulated by matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Matrix components of the basement membrane play critical roles in the development and maintenance of the neuromuscular junction (NMJ), yet almost nothing is known about the regulation of MMP and TIMP expression in either the pre- or postsynaptic compartments. Here, we demonstrate that TIMP-2 is expressed by both spinal motor neurons and skeletal muscle. To determine whether motor function is altered in the absence of TIMP-2, motor behavior was assessed using a battery of tests (e.g., RotaRod, balance beam, hindlimb extension, grip strength, loaded grid, and gait analysis). TIMP-2(-/-) mice fall off the RotaRod significantly faster than wild-type littermates. In addition, hindlimb extension is reduced and gait is both splayed and lengthened in TIMP-2(-/-) mice. Motor dysfunction is more pronounced during early postnatal development. A preliminary analysis revealed NMJ alterations in TIMP-2(-/-) mice. Juvenile TIMP-2(-/-) mice have increased nerve branching and acetylcholine receptor expression. Adult TIMP-2(-/-) endplates are enlarged and more complex. This suggests a role for TIMP-2 in NMJ sculpting during development. In contrast to the increased NMJ nerve branching, cerebellar Purkinje cells have decreased neurite outgrowth. Thus, the TIMP-2(-/-) motor phenotype is likely due to both peripheral and central defects. The tissue specificity of the nerve branching phenotype suggests the involvement of different MMPs and/or extracellular matrix molecules underlying the TIMP-2(-/-) motor phenotype.

Phosphodiesterase 4 inhibitors.

PubMed

Zebda, Rema; Paller, Amy S

2018-03-01

Historically, drugs available for treating atopic dermatitis (AD) have been limited to topical corticosteroids and topical calcineurin inhibitors, with systemic immunosuppressants and phototherapy reserved for severe AD. Despite their efficacy and infrequent adverse events, phobia about the use of topical steroids and calcineurin inhibitors has limited their use. More targeted options with fewer systemic and cutaneous side effects are needed for treating AD. Phosphodiesterase 4 (PDE4) is involved in the regulation of proinflammatory cytokines via the degradation of cyclic adenosine monophosphate. PDE4 activity is increased in the inflammatory cells of patients with AD, leading to increased production of proinflammatory cytokines and chemokines. Targeting PDE4 reduces the production of these proinflammatory mediators in AD. Both topical and oral PDE4 inhibitors have a favorable safety profile. Crisaborole 2% ointment, a topical PDE4, is now US Food and Drug Administration-approved for children older than 2 years and adults in the treatment of AD. Crisaborole 2% ointment shows early and sustained improvement in disease severity and pruritus and other AD symptoms, with burning and/or stinging upon application as the only related adverse event. Other PDE4 inhibitors are currently in trials with promising efficacy and safety. Copyright © 2017. Published by Elsevier Inc.

The multiple functions of plant serine protease inhibitors

PubMed Central

Giri, Ashok P; Kaur, Harleen; Baldwin, Ian T

2011-01-01

Plant protease inhibitors (PIs) are a diverse group of proteins which have been intensely investigated due to their potential function in protecting plants against herbivorous insects by inhibiting digestive proteases. Although this mechanism has been well documented for a number of single PIs and their target enzymes, whether this mechanism protects plants in nature remains unclear. Moreover, many plants express a number of different PIs and it was unknown if these proteins work synergistically as defenses or if they also have other functions. We recently identified four serine PIs (SPI) of Solanum nigrum and demonstrated that they differ substantially in substrate specificity, accumulation patterns, and their effect against different natural herbivorous insects in field- and glasshouse experiments. These differences suggest that SPIs have at least partially diversified to provide protection against different attackers. Although we could not detect effects on plant development or growth when silencing SPIs, gene- and tissue-specific expression patterns suggest multiple functions in generative tissues, including a possible involvement in development. PMID:22004998

RA190, a Proteasome Subunit ADRM1 Inhibitor, Suppresses Intrahepatic Cholangiocarcinoma by Inducing NF-KB-Mediated Cell Apoptosis.

PubMed

Yu, Guang-Yang; Wang, Xuan; Zheng, Su-Su; Gao, Xiao-Mei; Jia, Qing-An; Zhu, Wen-Wei; Lu, Lu; Jia, Hu-Liang; Chen, Jin-Hong; Dong, Qiong-Zhu; Lu, Ming; Qin, Lun-Xiu

2018-06-15

Effective drug treatment for intrahepatic cholangiocarcinoma (ICC) is currently lacking. Therefore, there is an urgent need for new targets and new drugs that can prolong patient survival. Recently targeting the ubiquitin proteasome pathway has become an attractive anti-cancer strategy. In this study, we aimed to evaluate the therapeutic effect of and identify the potential mechanisms involved in targeting the proteasome subunit ADRM1 for ICC. The expression of ADRM1 and its prognostic value in ICC was analyzed using GEO and TCGA datasets, tumor tissues, and tumor tissue arrays. The effects of RA190 on the proliferation and survival of both established ICC cell lines and primary ICC cells were examined in vitro. Annexin V/propidium iodide staining, western blotting and immunohistochemical staining were performed. The in vivo anti-tumor effect of RA190 on ICC was validated in subcutaneous xenograft and patient-derived xenograft (PDX) models. ADRM1 levels were significantly higher in ICC tissues than in normal bile duct tissues. ICC patients with high ADRM1 levels had worse overall survival (hazard ratio [HR] = 2.383, 95% confidence interval [CI] =1.357 to 4.188) and recurrence-free survival (HR = 1.710, 95% CI =1.045 to 2.796). ADRM1 knockdown significantly inhibited ICC growth in vitro and in vivo. The specific inhibitor RA190 targeting ADRM1 suppressed proliferation and reduced cell vitality of ICC cell lines and primary ICC cells significantly in vitro. Furthermore, RA190 significantly inhibited the proteasome by inactivating ADRM1, and the consequent accumulation of ADRM1 substrates decreased the activating levels of NF-κB to aggravate cell apoptosis. The therapeutic benefits of RA190 treatment were further demonstrated in both subcutaneous implantation and PDX models. Our findings indicate that up-regulated ADRM1 was involved in ICC progression and suggest the potential clinical application of ADRM1 inhibitors (e.g., RA190 and KDT-11) for ICC treatment. �

The Artemisinin Derivative Artemisone Is a Potent Inhibitor of Human Cytomegalovirus Replication.

PubMed

Oiknine-Djian, E; Weisblum, Y; Panet, A; Wong, H N; Haynes, R K; Wolf, D G

2018-04-30

Human cytomegalovirus (HCMV) is a major cause of disease in immunocompromised individuals and the most common cause of congenital infection and neuro-sensorial disease. The expanding target populations for HCMV antiviral treatment along with the limitations of the currently available HCMV DNA polymerase inhibitors underscore the need for new antiviral agents with alternative modes of action. The anti-malarial artemisinin derivative artesunate was shown to inhibit HCMV in vitro , yet has demonstrated limited antiviral efficacy in vivo , prompting our search for more potent anti-HCMV artemisinin derivatives. Here we show that the innovative artemisinin derivative artemisone, which has been screened against malaria in human clinical studies, is a potent and non-cytotoxic inhibitor of HCMV. Artemisone exhibited an antiviral efficacy comparable to ganciclovir (EC 50 1.20 ± 0.46 μM) in human foreskin fibroblasts, with enhanced relative potency in lung fibroblasts and epithelial cells. Significantly, the antiviral efficacy of artemisone was consistently ≥10-fold superior to that of artesunate in all cells. Artemisone effectively inhibited both laboratory-adapted and low-passage clinical strains, as well as drug-resistant HCMV strains. By using quantitative viral kinetics and gene expression studies, we showed that artemisone is a reversible inhibitor, targeting an earlier phase of the viral replication cycle than ganciclovir. Importantly, artemisone most effectively inhibited HCMV infection ex vivo in a clinically-relevant multicellular model of integral human placental tissues maintained in organ culture. Our promising findings encourage preclinical and clinical studies of artemisone as a new inhibitor against HCMV. Copyright © 2018 American Society for Microbiology.

Radiolabelling and positron emission tomography of PT70, a time-dependent inhibitor of InhA, the Mycobacterium tuberculosis enoyl-ACP reductase

DOE PAGES

Wang, Hui; Liu, Li; Lu, Yang; ...

2015-07-14

PT70 is a diaryl ether inhibitor of InhA, the enoyl-ACP reductase in the Mycobacterium tuberculosis fatty acid biosynthesis pathway. It has a residence time of 24 min on the target, and also shows antibacterial activity in a mouse model of tuberculosis infection. Due to the interest in studying target tissue pharmacokinetics of PT70, we developed a method to radiolabel PT70 with carbon-11 and have studied its pharmacokinetics in mice and baboons using positron emission tomography.

Radiolabelling and positron emission tomography of PT70, a time-dependent inhibitor of InhA, the Mycobacterium tuberculosis enoyl-ACP reductase

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

Wang, Hui; Liu, Li; Lu, Yang

PT70 is a diaryl ether inhibitor of InhA, the enoyl-ACP reductase in the Mycobacterium tuberculosis fatty acid biosynthesis pathway. It has a residence time of 24 min on the target, and also shows antibacterial activity in a mouse model of tuberculosis infection. Due to the interest in studying target tissue pharmacokinetics of PT70, we developed a method to radiolabel PT70 with carbon-11 and have studied its pharmacokinetics in mice and baboons using positron emission tomography.

Cocrystal Structures of Primed Side-Extending α-Ketoamide Inhibitors Reveal Novel Calpain-Inhibitor Aromatic Interactions

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

Qian,J.; Cuerrier, D.; Davies, P.

Calpains are intracellular cysteine proteases that catalyze the cleavage of target proteins in response to Ca2+ signaling. When Ca2+ homeostasis is disrupted, calpain overactivation causes unregulated proteolysis, which can contribute to diseases such as postischemic injury and cataract formation. Potent calpain inhibitors exist, but of these many cross-react with other cysteine proteases and will need modification to specifically target calpain. Here, we present crystal structures of rat calpain 1 protease core ({mu}I-II) bound to two a-ketoamide-based calpain inhibitors containing adenyl and piperazyl primed-side extensions. An unexpected aromatic-stacking interaction is observed between the primed-side adenine moiety and the Trp298 side chain.more » This interaction increased the potency of the inhibitor toward {mu}I-II and heterodimeric m-calpain. Moreover, stacking orients the adenine such that it can be used as a scaffold for designing novel primed-side address regions, which could be incorporated into future inhibitors to enhance their calpain specificity.« less

The effects of residual platelets in plasma on plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays.

PubMed

Pieters, Marlien; Barnard, Sunelle A; Loots, Du Toit; Rijken, Dingeman C

2017-01-01

Due to controversial evidence in the literature pertaining to the activity of plasminogen activator inhibitor-1 in platelets, we examined the effects of residual platelets present in plasma (a potential pre-analytical variable) on various plasminogen activator inhibitor-1 and plasminogen activator inhibitor-1-related assays. Blood samples were collected from 151 individuals and centrifuged at 352 and 1500 g to obtain plasma with varying numbers of platelet. In a follow-up study, blood samples were collected from an additional 23 individuals, from whom platelet-poor (2000 g), platelet-containing (352 g) and platelet-rich plasma (200 g) were prepared and analysed as fresh-frozen and after five defrost-refreeze cycles (to determine the contribution of in vitro platelet degradation). Plasminogen activator inhibitor-1 activity, plasminogen activator inhibitor-1 antigen, tissue plasminogen activator/plasminogen activator inhibitor-1 complex, plasma clot lysis time, β-thromboglobulin and plasma platelet count were analysed. Platelet α-granule release (plasma β-thromboglobulin) showed a significant association with plasminogen activator inhibitor-1 antigen levels but weak associations with plasminogen activator inhibitor-1 activity and a functional marker of fibrinolysis, clot lysis time. Upon dividing the study population into quartiles based on β-thromboglobulin levels, plasminogen activator inhibitor-1 antigen increased significantly across the quartiles while plasminogen activator inhibitor-1 activity and clot lysis time tended to increase in the 4th quartile only. In the follow-up study, plasma plasminogen activator inhibitor-1 antigen was also significantly influenced by platelet count in a concentration-dependent manner. Plasma plasminogen activator inhibitor-1 antigen levels increased further after complete platelet degradation. Residual platelets in plasma significantly influence plasma plasminogen activator inhibitor-1 antigen levels mainly through release of

Rho-associated kinase inhibitors: a novel glaucoma therapy.

PubMed

Inoue, Toshihiro; Tanihara, Hidenobu

2013-11-01

The rho-associated kinase (ROCK) signaling pathway is activated via secreted bioactive molecules or via integrin activation after extracellular matrix binding. These lead to polymerization of actin stress fibers and formation of focal adhesions. Accumulating evidence suggests that actin cytoskeleton-modulating signals are involved in aqueous outflow regulation. Aqueous humor contains various biologically active factors, some of which are elevated in glaucomatous eyes. These factors affect aqueous outflow, in part, through ROCK signaling modulation. Various drugs acting on the cytoskeleton have also been shown to increase aqueous outflow by acting directly on outflow tissue. In vivo animal studies have shown that the trabecular meshwork (TM) actin cytoskeleton in glaucomatous eyes is more disorganized and more randomly oriented than in non-glaucomatous control eyes. In a previous study, we introduced ROCK inhibitors as a potential glaucoma therapy by showing that a selective ROCK inhibitor significantly lowered rabbit IOP. Rho-associated kinase inhibitors directly affect the TM and Schlemm's canal (SC), differing from the target sight of other glaucoma drugs. The TM is affected earlier and more strongly than ciliary muscle cells by ROCK inhibitors, largely because of pharmacological affinity differences stemming from regulatory mechanisms. Additionally, ROCK inhibitors disrupt tight junctions, result in F-actin depolymerization, and modulate intracellular calcium level, effectively increasing SC-cell monolayer permeability. Perfusion of an enucleated eye with a ROCK inhibitor resulted in wider empty spaces in the juxtacanalicular (JCT) area and more giant vacuoles in the endothelial cells of SC, while the endothelial lining of SC was intact. Interestingly, ROCK inhibitors also increase retinal blood flow by relaxing vascular smooth muscle cells, directly protecting neurons against various stresses, while promoting wound healing. These additional effects may help

HIV-1 IN Inhibitors: 2010 Update and Perspectives

PubMed Central

Marchand, Christophe; Maddali, Kasthuraiah; Metifiot, Mathieu; Pommier, Yves

2010-01-01

Integrase (IN) is the newest validated target against AIDS and retroviral infections. The remarkable activity of raltegravir (Isentress®) led to its rapid approval by the FDA in 2007 as the first IN inhibitor. Several other IN strand transfer inhibitors (STIs) are in development with the primary goal to overcome resistance due to the rapid occurrence of IN mutations in raltegravir-treated patients. Thus, many scientists and drug companies are actively pursuing clinically useful IN inhibitors. The objective of this review is to provide an update on the IN inhibitors reported in the last two years, including second generation strand transfer inhibitors (STI), recently developed hydroxylated aromatics, natural products, peptide, antibody and oligonucleotide inhibitors. Additionally, the targeting of IN cofactors such as LEDGF and Vpr will be discussed as novel strategies for the treatment of AIDS. PMID:19747122

Reagent Precoated Targets for Rapid In-Tissue Derivatization of the Anti-Tuberculosis Drug Isoniazid Followed by MALDI Imaging Mass Spectrometry

NASA Astrophysics Data System (ADS)

Manier, M. Lisa; Reyzer, Michelle L.; Goh, Anne; Dartois, Veronique; Via, Laura E.; Barry, Clifton E.; Caprioli, Richard M.

2011-08-01

Isoniazid (INH) is an important component of front-line anti-tuberculosis therapy with good serum pharmacokinetics but unknown ability to penetrate tuberculous lesions. However, endogenous background interferences hinder our ability to directly analyze INH in tissues. Chemical derivatization has been successfully used to measure isoniazid directly from tissue samples using matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS). MALDI targets were pretreated with trans-cinnamaldehyde (CA) prior to mounting tissue slices. Isoniazid present in the tissues was efficiently derivatized and the INH-CA product measured by MS/MS. Precoating of MALDI targets allows the tissues to be directly thaw-mounted and derivatized, thus simplifying the preparation. A time-course series of tissues from tuberculosis infected/INH dosed animals were assayed and the MALDI MS/MS response correlates well with the amount of INH determined to be in the tissues by high-performance liquid chromatography (HPLC)-MS/MS.

Characterization of Covalent-Reversible EGFR Inhibitors

PubMed Central

2017-01-01

Within the spectrum of kinase inhibitors, covalent-reversible inhibitors (CRIs) provide a valuable alternative approach to classical covalent inhibitors. This special class of inhibitors can be optimized for an extended drug-target residence time. For CRIs, it was shown that the fast addition of thiols to electron-deficient olefins leads to a covalent bond that can break reversibly under proteolytic conditions. Research groups are just beginning to include CRIs in their arsenal of compound classes, and, with that, the understanding of this interesting set of chemical warheads is growing. However, systems to assess both characteristics of the covalent-reversible bond in a simple experimental setting are sparse. Here, we have developed an efficient methodology to characterize the covalent and reversible properties of CRIs and to investigate their potential in targeting clinically relevant variants of the receptor tyrosine kinase EGFR.

STAT inhibitors for cancer therapy

PubMed Central

2013-01-01

Signal Transducer and Activator of Transcription (STAT) proteins are a family of cytoplasmic transcription factors consisting of 7 members, STAT1 to STAT6, including STAT5a and STAT5b. STAT proteins are thought to be ideal targets for anti-cancer therapy since cancer cells are more dependent on the STAT activity than their normal counterparts. Inhibitors targeting STAT3 and STAT5 have been developed. These included peptidomimetics, small molecule inhibitors and oligonucleotides. This review summarized advances in preclinical and clinical development of these compounds. PMID:24308725

In silico identification of potential inhibitors targeting Streptococcus mutans sortase A

PubMed Central

Luo, Hao; Liang, Dan-Feng; Bao, Min-Yue; Sun, Rong; Li, Yuan-Yuan; Li, Jian-Zong; Wang, Xin; Lu, Kai-Min; Bao, Jin-Ku

2017-01-01

Dental caries is one of the most common chronic diseases and is caused by acid fermentation of bacteria adhered to the teeth. Streptococcus mutans (S. mutans) utilizes sortase A (SrtA) to anchor surface proteins to the cell wall and forms a biofilm to facilitate its adhesion to the tooth surface. Some plant natural products, especially several flavonoids, are effective inhibitors of SrtA. However, given the limited number of inhibitors and the development of drug resistance, the discovery of new inhibitors is urgent. Here, the high-throughput virtual screening approach was performed to identify new potential inhibitors of S. mutans SrtA. Two libraries were used for screening, and nine compounds that had the lowest scores were chosen for further molecular dynamics simulation, binding free energy analysis and absorption, distribution, metabolism, excretion and toxicity (ADMET) properties analysis. The results revealed that several similar compounds composed of benzofuran, thiadiazole and pyrrole, which exhibited good affinities and appropriate pharmacokinetic parameters, were potential inhibitors to impede the catalysis of SrtA. In addition, the carbonyl of these compounds can have a key role in the inhibition mechanism. These findings can provide a new strategy for microbial infection disease therapy. PMID:28358034

Acoustic Droplet Vaporization and Propulsion of Perfluorocarbon-Loaded Microbullets for Targeted Tissue Penetration and Deformation

PubMed Central

Kagan, Daniel; Benchimol, Michael J.; Claussen, Jonathan C.; Chuluun-Erdene, Erdembileg

2012-01-01

Acoustic droplet vaporization of perfluorocarbon-loaded microbullets triggered by an ultrasound pulse provides the necessary force to penetrate, cleave, and deform cellular tissue for potential targeted drug delivery and precision nanosurgery. PMID:22692791

Anticoagulation beyond direct thrombin and factor Xa inhibitors: indications for targeting the intrinsic pathway?

PubMed

van Montfoort, Maurits L; Meijers, Joost C M

2013-08-01

Antithrombotic drugs like vitamin K antagonists and heparin have been the gold standard for the treatment and prevention of thromboembolic disease for many years. Unfortunately, there are several disadvantages of these antithrombotic drugs: they are accompanied by serious bleeding problems, it is necessary to monitor the therapeutic window, and there are various interactions with food and other drugs. This has led to the development of new oral anticoagulants, specifically inhibiting either thrombin or factor Xa. In terms of effectiveness, these drugs are comparable to the currently available anticoagulants; however, they are still associated with issues such as bleeding, reversal of the drug and complicated laboratory monitoring. Vitamin K antagonists, heparin, direct thrombin and factor Xa inhibitors have in common that they target key proteins of the haemostatic system. In an attempt to overcome these difficulties we investigated whether the intrinsic coagulation factors (VIII, IX, XI, XII, prekallikrein and high-molecular-weight kininogen) are superior targets for anticoagulation. We analysed epidemiological data concerning thrombosis and bleeding in patients deficient in one of the intrinsic pathway proteins. Furthermore, we discuss several thrombotic models in intrinsic coagulation factor-deficient animals. The combined results suggest that intrinsic coagulation factors could be suitable targets for anticoagulant drugs.

Non-target-site resistance to ALS inhibitors in waterhemp (Amaranthus tuberculatus)

USDA-ARS?s Scientific Manuscript database

A waterhemp population (MCR) previously characterized as resistant to 4-hyroxyphenylpyruvate dioxygenase (HPPD) and photosystem II (PSII) inhibitors was found to have two different resistance responses to acetolactate synthase (ALS) inhibitors. Plants from the MCR population exhibiting high resistan...

Tricyclic Covalent Inhibitors Selectively Target Jak3 through an Active Site Thiol*

PubMed Central

Goedken, Eric R.; Argiriadi, Maria A.; Banach, David L.; Fiamengo, Bryan A.; Foley, Sage E.; Frank, Kristine E.; George, Jonathan S.; Harris, Christopher M.; Hobson, Adrian D.; Ihle, David C.; Marcotte, Douglas; Merta, Philip J.; Michalak, Mark E.; Murdock, Sara E.; Tomlinson, Medha J.; Voss, Jeffrey W.

2015-01-01

The action of Janus kinases (JAKs) is required for multiple cytokine signaling pathways, and as such, JAK inhibitors hold promise for treatment of autoimmune disorders, including rheumatoid arthritis, inflammatory bowel disease, and psoriasis. However, due to high similarity in the active sites of the four members (Jak1, Jak2, Jak3, and Tyk2), developing selective inhibitors within this family is challenging. We have designed and characterized substituted, tricyclic Jak3 inhibitors that selectively avoid inhibition of the other JAKs. This is accomplished through a covalent interaction between an inhibitor containing a terminal electrophile and an active site cysteine (Cys-909). We found that these ATP competitive compounds are irreversible inhibitors of Jak3 enzyme activity in vitro. They possess high selectivity against other kinases and can potently (IC50 < 100 nm) inhibit Jak3 activity in cell-based assays. These results suggest irreversible inhibitors of this class may be useful selective agents, both as tools to probe Jak3 biology and potentially as therapies for autoimmune diseases. PMID:25552479

Tricyclic Covalent Inhibitors Selectively Target Jak3 through an Active Site Thiol

DOE PAGES

Goedken, Eric R.; Argiriadi, Maria A.; Banach, David L.; ...

2014-12-31

The action of Janus kinases (JAKs) is required for multiple cytokine signaling pathways, and as such, JAK inhibitors hold promise for treatment of autoimmune disorders, including rheumatoid arthritis, inflammatory bowel disease, and psoriasis. However, due to high similarity in the active sites of the four members (Jak1, Jak2, Jak3, and Tyk2), developing selective inhibitors within this family is challenging. In this paper, we have designed and characterized substituted, tricyclic Jak3 inhibitors that selectively avoid inhibition of the other JAKs. This is accomplished through a covalent interaction between an inhibitor containing a terminal electrophile and an active site cysteine (Cys-909). Wemore » found that these ATP competitive compounds are irreversible inhibitors of Jak3 enzyme activity in vitro. They possess high selectivity against other kinases and can potently (IC 50 < 100 nM) inhibit Jak3 activity in cell-based assays. Finally, these results suggest irreversible inhibitors of this class may be useful selective agents, both as tools to probe Jak3 biology and potentially as therapies for autoimmune diseases.« less

Tricyclic Covalent Inhibitors Selectively Target Jak3 through an Active Site Thiol

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

Goedken, Eric R.; Argiriadi, Maria A.; Banach, David L.

The action of Janus kinases (JAKs) is required for multiple cytokine signaling pathways, and as such, JAK inhibitors hold promise for treatment of autoimmune disorders, including rheumatoid arthritis, inflammatory bowel disease, and psoriasis. However, due to high similarity in the active sites of the four members (Jak1, Jak2, Jak3, and Tyk2), developing selective inhibitors within this family is challenging. In this paper, we have designed and characterized substituted, tricyclic Jak3 inhibitors that selectively avoid inhibition of the other JAKs. This is accomplished through a covalent interaction between an inhibitor containing a terminal electrophile and an active site cysteine (Cys-909). Wemore » found that these ATP competitive compounds are irreversible inhibitors of Jak3 enzyme activity in vitro. They possess high selectivity against other kinases and can potently (IC 50 < 100 nM) inhibit Jak3 activity in cell-based assays. Finally, these results suggest irreversible inhibitors of this class may be useful selective agents, both as tools to probe Jak3 biology and potentially as therapies for autoimmune diseases.« less

Peptidase inhibitors in tick physiology.

PubMed

Parizi, L F; Ali, A; Tirloni, L; Oldiges, D P; Sabadin, G A; Coutinho, M L; Seixas, A; Logullo, C; Termignoni, C; DA Silva Vaz, I

2018-06-01

Peptidase inhibitors regulate a wide range of physiological processes involved in the interaction between hematophagous parasites and their hosts, including tissue remodeling, the immune response and blood coagulation. In tick physiology, peptidase inhibitors have a crucial role in adaptation to improve parasitism mechanisms, facilitating blood feeding by interfering with defense-related host peptidases. Recently, a larger number of studies on this topic led to the description of several new tick inhibitors displaying interesting novel features, for example a role in pathogen transmission to the host. A comprehensive review discussing these emerging concepts can therefore shed light on peptidase inhibitor functions, their relevance to tick physiology and their potential applications. Here, we summarize and examine the general characteristics, functional diversity and action of tick peptidase inhibitors with known physiological roles in the tick-host-pathogen interaction. © 2017 The Royal Entomological Society.

Targeting connective tissue growth factor (CTGF) in acute lymphoblastic leukemia preclinical models: anti-CTGF monoclonal antibody attenuates leukemia growth.

PubMed

Lu, Hongbo; Kojima, Kensuke; Battula, Venkata Lokesh; Korchin, Borys; Shi, Yuexi; Chen, Ye; Spong, Suzanne; Thomas, Deborah A; Kantarjian, Hagop; Lock, Richard B; Andreeff, Michael; Konopleva, Marina

2014-03-01

Connective tissue growth factor (CTGF/CCN2) is involved in extracellular matrix production, tumor cell proliferation, adhesion, migration, and metastasis. Recent studies have shown that CTGF expression is elevated in precursor B-acute lymphoblastic leukemia (ALL) and that increased expression of CTGF is associated with inferior outcome in B-ALL. In this study, we characterized the functional role and downstream signaling pathways of CTGF in ALL cells. First, we utilized lentiviral shRNA to knockdown CTGF in RS4;11 and REH ALL cells expressing high levels of CTGF mRNA. Silencing of CTGF resulted in significant suppression of leukemia cell growth compared to control vector, which was associated with AKT/mTOR inactivation and increased levels of cyclin-dependent kinase inhibitor p27. CTGF knockdown sensitized ALL cells to vincristine and methotrexate. Treatment with an anti-CTGF monoclonal antibody, FG-3019, significantly prolonged survival of mice injected with primary xenograft B-ALL cells when co-treated with conventional chemotherapy (vincristine, L-asparaginase and dexamethasone). Data suggest that CTGF represents a targetable molecular aberration in B-ALL, and blocking CTGF signaling in conjunction with administration of chemotherapy may represent a novel therapeutic approach for ALL patients.

Targeting the sugar metabolism of tumors with a first-in-class 6-phosphofructo-2-kinase (PFKFB4) inhibitor.

PubMed

Chesney, Jason; Clark, Jennifer; Lanceta, Lilibeth; Trent, John O; Telang, Sucheta

2015-07-20

Human tumors exhibit increased glucose uptake and metabolism as a result of high demand for ATP and anabolic substrates and this metabolotype is a negative prognostic indicator for survival. Recent studies have demonstrated that cancer cells from several tissue origins and genetic backgrounds require the expression of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4 (PFKFB4), a regulatory enzyme that synthesizes an allosteric activator of glycolysis, fructose-2,6-bisphosphate. We report the discovery of a first-in-class PFKFB4 inhibitor, 5-(n-(8-methoxy-4-quinolyl)amino)pentyl nitrate (5MPN), using structure-based virtual computational screening. We find that 5MPN is a selective inhibitor of PFKFB4 that suppresses the glycolysis and proliferation of multiple human cancer cell lines but not non-transformed epithelial cells in vitro. Importantly, 5MPN has high oral bioavailability and per os administration of a non-toxic dose of 5MPN suppresses the glucose metabolism and growth of tumors in mice.

Rhodium(II) proximity-labeling identifies a novel target site on STAT3 for inhibitors with potent anti-leukemia activity

PubMed Central

Minus, Matthew B.; Liu, Wei; Vohidov, Farrukh; Kasembeli, Moses M.; Long, Xin; Krueger, Michael; Stevens, Alexandra; Kolosov, Mikhail I.; Sison, Edward Allen R.; Ball, Zachary T.

2015-01-01

Nearly 40% of children with acute myeloid leukemia (AML) suffer relapse due to chemoresistance, often involving upregulation of the oncoprotein STAT3 (signal transducer and activator of transcription 3). In this paper, rhodium(II)-catalyzed, proximity-driven modification identifies the STAT3 coiled-coil domain (CCD) as a novel ligand-binding site, and we describe a new naphthalene sulfonamide inhibitor that targets the CCD, blocks STAT3 function, and halts its disease-promoting effects in vitro, in tumor growth models, and in a leukemia mouse model, validating this new therapeutic target for resistant AML. PMID:26480340

Targeting of glutamine transporter ASCT2 and glutamine synthetase suppresses gastric cancer cell growth.

PubMed

Ye, Jianxin; Huang, Qiang; Xu, Jie; Huang, Jinsheng; Wang, Jinzhou; Zhong, Wenjing; Chen, Wannan; Lin, Xinjian; Lin, Xu

2018-05-01

Glutamine (Gln) is essential for the proliferation of most cancer cells, making it an appealing target for cancer therapy. However, the role of Gln in gastric cancer (GC) metabolism is unknown and Gln-targeted therapy against GC remains scarce. The aim of this study was to investigate the relevance of Gln in GC growth and targeting. Expression of Gln transporter ASCT2 and glutamine synthetase (GS) in the parental and molecularly engineered GC cells or in human GC specimens was determined by RT-PCR and western blot analysis or immunohistochemistry. Cell proliferation and survival was assessed by CCK-8 assay and colony formation assay. Intracellular Gln content was measured by a HPLC system. Effects of ASCT2 and/or GS inhibitor on tumor growth were investigated in xenograft models. A significant heterogeneity of GC cells was observed with respect to their response to the treatment of ASCT2 inhibitor benzylserine (BenSer). Gln deprivation did not affect the BenSer-resistant cell growth due to endogenous GS expression, whose inhibition remarkably reduced cell proliferation. The differential in vitro sensitivity correlated with overall intracellular Gln content. Combined therapy with both ASCT2 and GS inhibitors produced a greater therapeutic efficacy than the treatment of either inhibitor alone. Furthermore, 77% human GC tissues were found to express moderate and high levels of ASCT2, 12% of which also co-expressed relatively high levels of GS. Gln mediates GC growth and the therapeutic efficacy of Gln-targeted treatment relies on distinct ASCT2 and GS expression pattern in specific gastric cancer groups.

Phylotranscriptomic analysis uncovers a wealth of tissue inhibitor of metalloproteinases variants in echinoderms

PubMed Central

Clouse, Ronald M.; Linchangco, Gregorio V.; Kerr, Alexander M.; Reid, Robert W.; Janies, Daniel A.

2015-01-01

Tissue inhibitors of metalloproteinases (TIMPs) help regulate the extracellular matrix (ECM) in animals, mostly by inhibiting matrix metalloproteinases (MMPs). They are important activators of mutable collagenous tissue (MCT), which have been extensively studied in echinoderms, and the four TIMP copies in humans have been studied for their role in cancer. To understand the evolution of TIMPs, we combined 405 TIMPs from an echinoderm transcriptome dataset built from 41 specimens representing all five classes of echinoderms with variants from protostomes and chordates. We used multiple sequence alignment with various stringencies of alignment quality to cull highly divergent sequences and then conducted phylogenetic analyses using both nucleotide and amino acid sequences. Phylogenetic hypotheses consistently recovered TIMPs as diversifying in the ancestral deuterostome and these early lineages continuing to diversify in echinoderms. The four vertebrate TIMPs diversified from a single copy in the ancestral chordate, all other copies being lost. Consistent with greater MCT needs owing to body wall liquefaction, evisceration, autotomy and reproduction by fission, holothuroids had significantly more TIMPs and higher read depths per contig. Ten cysteine residues, an HPQ binding site and several other residues were conserved in at least 70% of all TIMPs. The conservation of binding sites and the placement of echinoderm TIMPs involved in MCT modification suggest that ECM regulation remains the primary function of TIMP genes, although within this role there are a large number of specialized copies. PMID:27017967

A method for direct assessment of tissue-nonspecific alkaline phosphatase (TNAP) inhibitors in blood samples.

PubMed

Sergienko, Eduard A; Sun, Qing; Ma, Chen-Ting

2013-01-01

Tissue nonspecific alkaline phosphatase (TNAP) is one of four human alkaline phosphatases (AP), a family of exocytic enzymes that catalyze hydrolysis of phospho-monoesters in bone, liver, kidney, and various other tissues. Overexpression of TNAP gives rise to excessive bone and soft tissue mineralization, including blood vessel calcification. Our prior screening campaigns have found several leads against this attractive therapeutic target using in vitro assay with a recombinant enzyme; these compounds were further optimized using medicinal chemistry approaches. To prioritize compounds for their use in animal models, we have designed and developed a biomarker assay for in situ detection of TNAP activity within human and mouse blood samples at physiological pH. This assay is suitable for screening compounds in 1,536-well plates using blood plasma from different mammalian species. The user may choose from two different substrates based on the need for greater assay simplicity or sensitivity.

Blueprint for antimicrobial hit discovery targeting metabolic networks.

PubMed

Shen, Y; Liu, J; Estiu, G; Isin, B; Ahn, Y-Y; Lee, D-S; Barabási, A-L; Kapatral, V; Wiest, O; Oltvai, Z N

2010-01-19

Advances in genome analysis, network biology, and computational chemistry have the potential to revolutionize drug discovery by combining system-level identification of drug targets with the atomistic modeling of small molecules capable of modulating their activity. To demonstrate the effectiveness of such a discovery pipeline, we deduced common antibiotic targets in Escherichia coli and Staphylococcus aureus by identifying shared tissue-specific or uniformly essential metabolic reactions in their metabolic networks. We then predicted through virtual screening dozens of potential inhibitors for several enzymes of these reactions and showed experimentally that a subset of these inhibited both enzyme activities in vitro and bacterial cell viability. This blueprint is applicable for any sequenced organism with high-quality metabolic reconstruction and suggests a general strategy for strain-specific antiinfective therapy.

Design and synthetic considerations of matrix metalloproteinase inhibitors.

PubMed

Skotnicki, J S; Zask, A; Nelson, F C; Albright, J D; Levin, J I

1999-06-30

Experimental evidence confirms that the matrix metalloproteinases (MMPs) play a fundamental role in a wide variety of pathologic conditions that involve connective tissue destruction including osteoarthritis and rheumatoid arthritis, tumor metastasis and angiogenesis, corneal ulceration, multiple sclerosis, periodontal disease, and atherosclerosis. Modulation of MMP regulation is possible at several biochemical sites, but direct inhibition of enzyme action provides a particularly attractive target for therapeutic intervention. Hypotheses concerning inhibition of specific MMP(s) with respect to disease target and/or side-effect profile have emerged. Examples are presented of recent advances in medicinal chemistry approaches to the design of matrix metalloproteinase inhibitors (MMPIs), approaches that address structural requirements and that influence potency, selectivity, and bioavailability. Two important approaches to the design, synthesis, and biological evaluation of MMPIs are highlighted: (1) the invention of alternatives to hydroxamic acid zinc chelators and (2) the construction of nonpeptide scaffolds. One current example in each of these two approaches from our own work is described.

Bacterial Cell Growth Inhibitors Targeting Undecaprenyl Diphosphate Synthase and Undecaprenyl Diphosphate Phosphatase.

PubMed

Wang, Yang; Desai, Janish; Zhang, Yonghui; Malwal, Satish R; Shin, Christopher J; Feng, Xinxin; Sun, Hong; Liu, Guizhi; Guo, Rey-Ting; Oldfield, Eric

2016-10-19

We synthesized a series of benzoic acids and phenylphosphonic acids and investigated their effects on the growth of Staphylococcus aureus and Bacillus subtilis. One of the most active compounds, 5-fluoro-2-(3-(octyloxy)benzamido)benzoic acid (7, ED 50 ∼0.15 μg mL -1 ) acted synergistically with seven antibiotics known to target bacterial cell-wall biosynthesis (a fractional inhibitory concentration index (FICI) of ∼0.35, on average) but had indifferent effects in combinations with six non-cell-wall biosynthesis inhibitors (average FICI∼1.45). The most active compounds were found to inhibit two enzymes involved in isoprenoid/bacterial cell-wall biosynthesis: undecaprenyl diphosphate synthase (UPPS) and undecaprenyl diphosphate phosphatase (UPPP), but not farnesyl diphosphate synthase, and there were good correlations between bacterial cell growth inhibition, UPPS inhibition, and UPPP inhibition. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Grapevine VvPMEI1 Gene Encodes a Novel Functional Pectin Methylesterase Inhibitor Associated to Grape Berry Development

PubMed Central

Lionetti, Vincenzo; Raiola, Alessandro; Mattei, Benedetta; Bellincampi, Daniela

2015-01-01

Pectin is secreted in a highly methylesterified form and partially de-methylesterified in the cell wall by pectin methylesterases (PMEs). PME activity is expressed during plant growth, development and stress responses. PME activity is controlled at the post-transcriptional level by proteins named PME inhibitors (PMEIs). We have identified, expressed and characterized VvPMEI1, a functional PME inhibitor of Vitis vinifera. VvPMEI1 typically affects the activity of plant PMEs and is inactive against microbial PMEs. The kinetics of PMEI-PME interaction, studied by surface plasmon resonance, indicates that the inhibitor strongly interacts with PME at apoplastic pH while the stability of the complex is reduced by increasing the pH. The analysis of VvPMEI1 expression in different grapevine tissues and during grape fruit development suggests that this inhibitor controls PME activity mainly during the earlier phase of berry development. A proteomic analysis performed at this stage indicates a PME isoform as possible target of VvPMEI1. PMID:26204516

Sphingosine-1-phosphate suppresses chondrosarcoma metastasis by upregulation of tissue inhibitor of metalloproteinase 3 through suppressing miR-101 expression.

PubMed

Tsai, Chun-Hao; Yang, Dong-Ying; Lin, Chih-Yang; Chen, Tsung-Ming; Tang, Chih-Hsin; Huang, Yuan-Li

2017-10-01

Chondrosarcoma is the second most common primary malignancy form of bone cancer, exhibiting resistance to chemotherapy and radiation therapy as well as developing high metastasis ability in late-stage tumors. Thus, understanding the metastatic processes of chondrosarcoma is considered a strategy for the treatment of this disease. Sphingosine 1-phosphate (S1P), a bioactive sphingolipid, is produced intracellularly by sphingosine kinase (SphK) and is regarded as a second signaling molecule that regulates inflammation, proliferation, angiogenesis, and metastasis. However, the effect of S1P on chondrosarcoma remains uncertain. As demonstrated by the transwell, immunoblotting, and real-time PCR analyses, we found that S1P inhibited cell migration and MMP-2 expression through the upregulation of the tissue inhibitor of metalloproteinase-3 (TIMP-3) expression in human chondrosarcoma cells. Additionally, we also showed that microRNA (miRNA)-101, which targets the 3' untranslated region (3'UTR) of TIMP-3, decreased significantly following S1P treatment. After transfection with miR-101 mimics, the S1P-regulated cell migration and TIMP-3 expression were both reversed. Furthermore, we also showed that the S1P-inhibited cell migration is mediated through the c-Src/MEK/ERK signaling axis. Meanwhile, the in vivo study indicated that overexpression of SphK1 decreases chondrosarcoma metastasis to the lungs. Our results illustrate the clinical significance between SphK1, TIMP-3, and miR-101 in human chondrosarcoma patients. Taken together, our results suggest that S1P and miR-101 may prove to be potential therapeutic targets for future chondrosarcoma treatment. © 2017 The Authors. Published by FEBS Press and John Wiley & Sons Ltd.

Synergistic anti-tumor effect of 17AAG with the PI3K/mTOR inhibitor NVP-BEZ235 on human melanoma.

PubMed

Calero, R; Morchon, E; Martinez-Argudo, I; Serrano, R

2017-10-10

Drug resistance by MAPK signaling recovery or activation of alternative signaling pathways, such as PI3K/AKT/mTOR, is an important factor that limits the long-term efficacy of targeted therapies in melanoma patients. In the present study, we investigated the phospho-proteomic profile of RTKs and its correlation with downstream signaling pathways in human melanoma. We found that tyrosine kinase receptors expression correlated with the expression of pivotal downstream components of the RAS/RAF/MAPK and PI3K/AKT/mTOR pathways in melanoma cell lines and tumors. We also found high expression of HSP90 and the PI3K/AKT/mTOR pathway proteins, 4EBP1 and AKT compared with healthy tissue and this correlated with poor overall survival of melanoma patients. The combination of the HSP90 inhibitor 17AAG with the PI3K/mTOR inhibitor NVP-BEZ235 showed a synergistic activity decreasing melanoma cell growth, inducing apoptosis and targeting simultaneously the MAPK and PI3K/AKT/mTOR pathways. These results demonstrate that the combination of HSP90 and PI3K/mTOR inhibitors could be an effective therapeutic strategy that target the main survival pathways in melanoma and must be considered to overcome resistance to BRAF inhibitors in melanoma patients. Copyright © 2017 Elsevier B.V. All rights reserved.

A Novel Oncolytic Herpes Simplex Virus that Synergizes with Phosphatidylinositol 3-Kinase/Akt Pathway Inhibitors to Target Glioblastoma Stem Cells

PubMed Central

Kanai, Ryuichi; Wakimoto, Hiroaki; Martuza, Robert L.; Rabkin, Samuel D.

2011-01-01

Purpose To develop a new oncolytic herpes simplex virus (oHSV) for glioblastoma therapy that will be effective in glioblastoma stem cells (GSCs), an important and untargeted component of glioblastoma. One approach to enhance oHSV efficacy is by combination with other therapeutic modalities. Experimental design MG18L, containing a US3 deletion and an inactivating LacZ insertion in UL39, was constructed for the treatment of brain tumors. Safety was evaluated after intracerebral injection in HSV-susceptible mice. The efficacy of MG18L in human GSCs and glioma cell lines in vitro was compared to other oHSVs, alone or in combination with PI3K/Akt inhibitors (LY294002, triciribine, GDC-0941, BEZ235). Cytotoxic interactions between MG18L and PI3K/Akt inhibitors were determined using Chou-Talalay analysis. In vivo efficacy studies were performed using a clinically relevant mouse model of GSC-derived glioblastoma. Results MG18L was severely neuroattenuated in mice, replicated well in GSCs, and had anti-glioblastoma activity in vivo. PI3K/Akt inhibitors displayed significant but variable anti-proliferative activities in GSCs, while their combination with MG18L synergized in killing GSCs and glioma lines, but not human astrocytes, through enhanced induction of apoptosis. Importantly, synergy was independent of inhibitor sensitivity. In vivo, the combination of MG18L and LY294002 significantly prolonged survival of mice, as compared to either agent alone, achieving 50% long-term survival in glioblastoma-bearing mice. Conclusions This study establishes a novel therapeutic strategy: oHSV manipulation of critical oncogenic pathways to sensitize cancer cells to molecularly-targeted drugs. MG18L is a promising agent for the treatment of glioblastoma, being especially effective when combined with PI3K/Akt pathway-targeted agents. PMID:21505062

Mechanisms involved in the transport of mercuric ions in target tissues

PubMed Central

Bridges, Christy C.; Zalups, Rudolfs K.

2016-01-01

Mercury exists in the environment in various forms, all of which pose a risk to human health. Despite guidelines regulating the industrial release of mercury into the environment, humans continue to be exposed regularly to various forms of this metal via inhalation or ingestion. Following exposure, mercuric ions are taken up by and accumulate in numerous organs, including brain, intestine, kidney, liver, and placenta. In order to understand the toxicological effects of exposure to mercury, a thorough understanding of the mechanisms that facilitate entry of mercuric ions into target cells must first be obtained. A number of mechanisms for the transport of mercuric ions into target cells and organs have been proposed in recent years. However, the ability of these mechanisms to transport mercuric ions and the regulatory features of these carriers have not been characterized completely. The purpose of this review is to summarize the current findings related to the mechanisms that may be involved in the transport of inorganic and organic forms of mercury in target tissues and organs. This review will describe mechanisms known to be involved in the transport of mercury and will also propose additional mechanisms that may potentially be involved in the transport of mercuric ions into target cells. PMID:27422290

The Replication Focus Targeting Sequence (RFTS) Domain Is a DNA-competitive Inhibitor of Dnmt1

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

Syeda, Farisa; Fagan, Rebecca L.; Wean, Matthew

Dnmt1 (DNA methyltransferase 1) is the principal enzyme responsible for maintenance of cytosine methylation at CpG dinucleotides in the mammalian genome. The N-terminal replication focus targeting sequence (RFTS) domain of Dnmt1 has been implicated in subcellular localization, protein association, and catalytic function. However, progress in understanding its function has been limited by the lack of assays for and a structure of this domain. Here, we show that the naked DNA- and polynucleosome-binding activities of Dnmt1 are inhibited by the RFTS domain, which functions by virtue of binding the catalytic domain to the exclusion of DNA. Kinetic analysis with a fluorogenicmore » DNA substrate established the RFTS domain as a 600-fold inhibitor of Dnmt1 enzymatic activity. The crystal structure of the RFTS domain reveals a novel fold and supports a mechanism in which an RFTS-targeted Dnmt1-binding protein, such as Uhrf1, may activate Dnmt1 for DNA binding.« less

Prevotella intermedia stimulates tissue-type plasminogen activator and plasminogen activator inhibitor-2 expression via multiple signaling pathways in human periodontal ligament cells.

PubMed

Guan, Su-Min; He, Jian-Jun; Zhang, Ming; Shu, Lei

2011-06-01

Prevotella intermedia is an important periodontal pathogen that induces various inflammatory and immune responses. In this study, we investigated the effects of P. intermedia on the plasminogen system in human periodontal ligament (hPDL) cells and explored the signaling pathways involved. Using semi-quantitative reverse transcription (RT)-PCR and quantitative real-time RT-qPCR, we demonstrated that P. intermedia challenge increased tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor (PAI)-2 expression in a concentration- and time-dependent manner, but exerted no influence on urokinase-type plasminogen activator and PAI-1mRNA expression in hPDL cells. Prevotella intermedia stimulation also enhanced tPA protein secretion as confirmed by enzyme-linked immunosorbent assay. Western blot results revealed that P. intermedia treatment increased phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 kinase (p38). ERK, JNK and protein kinase C inhibitors significantly attenuated the P. intermedia-induced tPA and PAI-2 expression. Furthermore, p38 and phosphatidylinositol 3-kinase inhibitors markedly decreased PAI-2 expression, whereas they showed no or little inhibition on tPA expression. In contrast, inhibition of protein kinase A greatly enhanced the upregulatory effect of P. intermedia on tPA and PAI-2 expression. Our results suggest that P. intermedia may contribute to periodontal tissue destruction by upregulating tPA and PAI-2 expression in hPDL cells via multiple signaling pathways. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Targeting Homologous Recombination by Pharmacological Inhibitors Enhances the Killing Response of Glioblastoma Cells Treated with Alkylating Drugs.

PubMed

Berte, Nancy; Piée-Staffa, Andrea; Piecha, Nadine; Wang, Mengwan; Borgmann, Kerstin; Kaina, Bernd; Nikolova, Teodora

2016-11-01

Malignant gliomas exhibit a high level of intrinsic and acquired drug resistance and have a dismal prognosis. First- and second-line therapeutics for glioblastomas are alkylating agents, including the chloroethylating nitrosoureas (CNU) lomustine, nimustine, fotemustine, and carmustine. These agents target the tumor DNA, forming O 6 -chloroethylguanine adducts and secondary DNA interstrand cross-links (ICL). These cross-links are supposed to be converted into DNA double-strand breaks, which trigger cell death pathways. Here, we show that lomustine (CCNU) with moderately toxic doses induces ICLs in glioblastoma cells, inhibits DNA replication fork movement, and provokes the formation of DSBs and chromosomal aberrations. Since homologous recombination (HR) is involved in the repair of DSBs formed in response to CNUs, we elucidated whether pharmacologic inhibitors of HR might have impact on these endpoints and enhance the killing effect. We show that the Rad51 inhibitors RI-1 and B02 greatly ameliorate DSBs, chromosomal changes, and the level of apoptosis and necrosis. We also show that an inhibitor of MRE11, mirin, which blocks the formation of the MRN complex and thus the recognition of DSBs, has a sensitizing effect on these endpoints as well. In a glioma xenograft model, the Rad51 inhibitor RI-1 clearly enhanced the effect of CCNU on tumor growth. The data suggest that pharmacologic inhibition of HR, for example by RI-1, is a reasonable strategy for enhancing the anticancer effect of CNUs. Mol Cancer Ther; 15(11); 2665-78. ©2016 AACR. ©2016 American Association for Cancer Research.

Insight into the Selectivity of the G7-18NATE Inhibitor Peptide for the Grb7-SH2 Domain Target.

PubMed

Watson, Gabrielle M; Lucas, William A H; Gunzburg, Menachem J; Wilce, Jacqueline A

2017-01-01

Growth factor receptor bound protein 7 (Grb7) is an adaptor protein with established roles in the progression of both breast and pancreatic cancers. Through its C-terminal SH2 domain, Grb7 binds to phosphorylated tyrosine kinases to promote proliferative and migratory signaling. Here, we investigated the molecular basis for the specificity of a Grb7 SH2-domain targeted peptide inhibitor. We identified that arginine 462 in the BC loop is unique to Grb7 compared to Grb2, another SH2 domain bearing protein that shares the same consensus binding motif as Grb7. Using surface plasmon resonance we demonstrated that Grb7-SH2 binding to G7-18NATE is reduced 3.3-fold when the arginine is mutated to the corresponding Grb2 amino acid. The reverse mutation in Grb2-SH2 (serine to arginine), however, was insufficient to restore binding of G7-18NATE to Grb2-SH2. Further, using a microarray, we confirmed that G7-18NATE is specific for Grb7 over a panel of 79 SH2 domains, and identified that leucine at the βD6 position may also be a requirement for Grb7-SH2 binding. This study provides insight into the specificity defining features of Grb7 for the inhibitor molecule G7-18NATE, that will assist in the development of improved Grb7 targeted inhibitors.

Insight into the Selectivity of the G7-18NATE Inhibitor Peptide for the Grb7-SH2 Domain Target

PubMed Central

Watson, Gabrielle M.; Lucas, William A. H.; Gunzburg, Menachem J.; Wilce, Jacqueline A.

2017-01-01

Growth factor receptor bound protein 7 (Grb7) is an adaptor protein with established roles in the progression of both breast and pancreatic cancers. Through its C-terminal SH2 domain, Grb7 binds to phosphorylated tyrosine kinases to promote proliferative and migratory signaling. Here, we investigated the molecular basis for the specificity of a Grb7 SH2-domain targeted peptide inhibitor. We identified that arginine 462 in the BC loop is unique to Grb7 compared to Grb2, another SH2 domain bearing protein that shares the same consensus binding motif as Grb7. Using surface plasmon resonance we demonstrated that Grb7-SH2 binding to G7-18NATE is reduced 3.3-fold when the arginine is mutated to the corresponding Grb2 amino acid. The reverse mutation in Grb2-SH2 (serine to arginine), however, was insufficient to restore binding of G7-18NATE to Grb2-SH2. Further, using a microarray, we confirmed that G7-18NATE is specific for Grb7 over a panel of 79 SH2 domains, and identified that leucine at the βD6 position may also be a requirement for Grb7-SH2 binding. This study provides insight into the specificity defining features of Grb7 for the inhibitor molecule G7-18NATE, that will assist in the development of improved Grb7 targeted inhibitors. PMID:29018805

Optimization of a binding fragment targeting the "enlarged methionine pocket" leads to potent Trypanosoma brucei methionyl-tRNA synthetase inhibitors.

PubMed

Huang, Wenlin; Zhang, Zhongsheng; Ranade, Ranae M; Gillespie, J Robert; Barros-Álvarez, Ximena; Creason, Sharon A; Shibata, Sayaka; Verlinde, Christophe L M J; Hol, Wim G J; Buckner, Frederick S; Fan, Erkang

2017-06-15

Potent inhibitors of Trypanosoma brucei methionyl-tRNA synthetase were previously designed using a structure-guided approach. Compounds 1 and 2 were the most active compounds in the cyclic and linear linker series, respectively. To further improve cellular potency, SAR investigation of a binding fragment targeting the "enlarged methionine pocket" (EMP) was performed. The optimization led to the identification of a 6,8-dichloro-tetrahydroquinoline ring as a favorable fragment to bind the EMP. Replacement of 3,5-dichloro-benzyl group (the EMP binding fragment) of inhibitor 2 using this tetrahydroquinoline fragment resulted in compound 13, that exhibited an EC 50 of 4nM. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multi-target screening mines hesperidin as a multi-potent inhibitor: Implication in Alzheimer's disease therapeutics.

PubMed

Chakraborty, Sandipan; Bandyopadhyay, Jaya; Chakraborty, Sourav; Basu, Soumalee

2016-10-04

Alzheimer's disease (AD) is the most frequent form of neurodegenerative disorder in elderly people. Involvement of several pathogenic events and their interconnections make this disease a complex disorder. Therefore, designing compounds that can inhibit multiple toxic pathways is the most attractive therapeutic strategy in complex disorders like AD. Here, we have designed a multi-tier screening protocol combining ensemble docking to mine BACE1 inhibitor, as well as 2-D QSAR models for anti-amyloidogenic and antioxidant activities. An in house developed phytochemical library of 200 phytochemicals has been screened through this multi-target procedure which mine hesperidin, a flavanone glycoside commonly found in citrus food items, as a multi-potent phytochemical in AD therapeutics. Steady-state and time-resolved fluorescence spectroscopy reveal that binding of hesperidin to the active site of BACE1 induces a conformational transition of the protein from open to closed form. Hesperidin docks close to the catalytic aspartate residues and orients itself in a way that blocks the cavity opening thereby precluding substrate binding. Hesperidin is a high affinity BACE1 inhibitor and only 500 nM of the compound shows complete inhibition of the enzyme activity. Furthermore, ANS and Thioflavin-T binding assay show that hesperidin completely inhibits the amyloid fibril formation which is further supported by atomic force microscopy. Hesperidin exhibits moderate ABTS(+) radical scavenging assay but strong hydroxyl radical scavenging ability, as evident from DNA nicking assay. Present study demonstrates the applicability of a novel multi-target screening procedure to mine multi-potent agents from natural origin for AD therapeutics. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Delayed treatment with recombinant human tissue factor pathway inhibitor improves survival in rabbits with gram-negative peritonitis.

PubMed

Camerota, A J; Creasey, A A; Patla, V; Larkin, V A; Fink, M P

1998-03-01

To determine whether treatment with recombinant human tissue factor pathway inhibitor (TFPI), an inhibitor of the extrinsic coagulation pathway, can improve survival in a clinically relevant model of gram-negative sepsis, rabbits were given an intraperitoneal inoculation of a suspension containing hemoglobin (40 microg/mL), porcine mucin (150 microg/mL), and viable Escherichia coli O18:K1 (1.0 +/- 0.5 x 10(5) cfu/kg). Treatment with gentamicin (5 mg/kg every 12 h for five doses) was instituted 4 h after induction of peritonitis. At the same time point, rabbits were randomized to receive a 24-h infusion of vehicle or one of three different doses of TFPI. Treatment groups, 7-day survival rates, and significance versus control were as follows: control, 1 of 20; TFPI(LOW DOSE) (0.1 mg/kg, then 1 microg/kg/min), 3 of 12 (P = .14); TFPI(MID DOSE), (0.5 mg/kg, then 5 microg/kg/min), 7 of 12 (P = .002); TFPI(HIGH DOSE) (10 mg/kg, then 10 microg/kg/min), 4 of 13 (P = .04). Thus, delayed treatment with TFPI improves survival in septic rabbits.

Targeting of X-linked inhibitor of apoptosis protein and PI3-kinase/AKT signaling by embelin suppresses growth of leukemic cells

PubMed Central

Prabhu, Kirti S.; Siveen, Kodappully S.; Kuttikrishnan, Shilpa; Iskandarani, Ahmad; Tsakou, Magdalini; Achkar, Iman W.; Therachiyil, Lubna; Krishnankutty, Roopesh; Parray, Aijaz; Kulinski, Michal; Merhi, Maysaloun; Dermime, Said; Mohammad, Ramzi M.

2017-01-01

The X-linked inhibitor of apoptosis (XIAP) is a viable molecular target for anticancer drugs that overcome apoptosis-resistance of malignant cells. XIAP is an inhibitor of apoptosis, mediating through its association with BIR3 domain of caspase 9. Embelin, a quinone derivative isolated from the Embelia ribes plant, has been shown to exhibit chemopreventive, anti-inflammatory, and apoptotic activities via inhibiting XIAP activity. In this study, we found that embelin causes a dose-dependent suppression of proliferation in leukemic cell lines K562 and U937. Embelin mediated inhibition of proliferation correlates with induction of apoptosis. Furthermore, embelin treatment causes loss of mitochondrial membrane potential and release of cytochrome c, resulting in subsequent activation of caspase-3 followed by polyadenosin-5’-diphosphate-ribose polymerase (PARP) cleavage. In addition, embelin treatment of leukemic cells results in a decrease of constitutive phosphorylations/activation level of AKT and downregulation of XIAP. Gene silencing of XIAP and AKT expression showed a link between XIAP expression and activated AKT in leukemic cells. Interestingly, targeting of XIAP and PI3-kinase/AKT signaling augmented inhibition of proliferation and induction of apoptosis in leukemic cells. Altogether these findings raise the possibility that embelin alone or in combination with inhibitors of PI3-kinase/AKT pathway may have therapeutic usage in leukemia and possibly other malignancies with up-regulated XIAP pathway. PMID:28704451

Targeting BET bromodomain proteins in solid tumors

PubMed Central

Sahai, Vaibhav; Redig, Amanda J.; Collier, Katharine A.; Eckerdt, Frank D.; Munshi, Hidayatullah G.

2016-01-01

There is increasing interest in inhibitors targeting BET (bromodomain and extra-terminal) proteins because of the association between this family of proteins and cancer progression. BET inhibitors were initially shown to have efficacy in hematologic malignancies; however, a number of studies have now shown that BET inhibitors can also block progression of non-hematologic malignancies. In this Review, we summarize the efficacy of BET inhibitors in select solid tumors; evaluate the role of BET proteins in mediating resistance to current targeted therapies; and consider potential toxicities of BET inhibitors. We also evaluate recently characterized mechanisms of resistance to BET inhibitors; summarize ongoing clinical trials with these inhibitors; and discuss potential future roles of BET inhibitors in patients with solid tumors. PMID:27283767

Molecular design of new aggrecanases-2 inhibitors.

PubMed

Shan, Zhi Jie; Zhai, Hong Lin; Huang, Xiao Yan; Li, Li Na; Zhang, Xiao Yun

2013-10-01

Aggrecanases-2 is a very important potential drug target for the treatment of osteoarthritis. In this study, a series of known aggrecanases-2 inhibitors was analyzed by the technologies of three-dimensional quantitative structure-activity relationships (3D-QSAR) and molecular docking. Two 3D-QSAR models, which based on comparative molecular field analysis (CoMFA) and comparative molecular similarity analysis (CoMSIA) methods, were established. Molecular docking was employed to explore the details of the interaction between inhibitors and aggrecanases-2 protein. According to the analyses for these models, several new potential inhibitors with higher activity predicted were designed, and were supported by the simulation of molecular docking. This work propose the fast and effective approach to design and prediction for new potential inhibitors, and the study of the interaction mechanism provide a better understanding for the inhibitors binding into the target protein, which will be useful for the structure-based drug design and modifications. Copyright © 2013 Elsevier Ltd. All rights reserved.

Efficient elimination of nonstoichiometric enzyme inhibitors from HTS hit lists.

PubMed

Habig, Michael; Blechschmidt, Anke; Dressler, Sigmar; Hess, Barbara; Patel, Viral; Billich, Andreas; Ostermeier, Christian; Beer, David; Klumpp, Martin

2009-07-01

High-throughput screening often identifies not only specific, stoichiometrically binding inhibitors but also undesired compounds that unspecifically interfere with the targeted activity by nonstoichiometrically binding, unfolding, and/or inactivating proteins. In this study, the effect of such unwanted inhibitors on several different enzyme targets was assessed based on screening results for over a million compounds. In particular, the shift in potency on variation of enzyme concentration was used as a means to identify nonstoichiometric inhibitors among the screening hits. These potency shifts depended on both compound structure and target enzyme. The approach was confirmed by statistical analysis of thousands of dose-response curves, which showed that the potency of competitive and therefore clearly stoichiometric inhibitors was not affected by increasing enzyme concentration. Light-scattering measurements of thermal protein unfolding further verified that compounds that stabilize protein structure by stoichiometric binding show the same potency irrespective of enzyme concentration. In summary, measuring inhibitor IC(50) values at different enzyme concentrations is a simple, cost-effective, and reliable method to identify and eliminate compounds that inhibit a specific target enzyme via nonstoichiometric mechanisms.

Mitomycin C dissolved in a reversible thermosetting gel: target tissue concentrations in the rabbit eye.

PubMed

Ichien, K; Yamamoto, T; Kitazawa, Y; Oguri, A; Ando, H; Kondo, Y

1997-01-01

To determine whether a new, reversible thermosetting gel enhances mitomycin C transfer to target ocular tissues in the rabbit eye. A 0.1 ml solution of mitomycin C containing 0.22 microgram, 2.9 micrograms, or 28 micrograms of the agent dissolved in a reversible thermosetting gel consisting of methylcellulose, citric acid, and polyethylene glycol was injected subconjunctivally in 30 New Zealand albino rabbits. Scleral and conjunctival tissues were excised at 0.5, 1, 2, 4, or 24 hours after the injection and mitomycin C concentrations in these tissues were determined by high performance liquid chromatography. The concentration over time was approximated to a single exponential curve, and initial mitomycin C concentrations, time constants, and half life values were determined. Finally, the areas under the curves (AUCs) between 0.5 and 24 hours were calculated. The mitomycin C concentrations in the target tissues were dose dependent and decreased rapidly over 24 hours. Both the initial mitomycin C concentrations as well as AUCs in these eyes treated with mitomycin C, dissolved in a reversible thermosetting gel, were higher than those in eyes treated similarly in a previous study in which the gel was not used. Applied subconjunctivally in the rabbit eye, mitomycin C dissolved in the reversible thermosetting gel enhanced transfer of the agent to the sclera and the conjunctiva.

ROCK as a therapeutic target for ischemic stroke.

PubMed

Sladojevic, Nikola; Yu, Brian; Liao, James K

2017-12-01

Stroke is a major cause of disability and the fifth leading cause of death. Currently, the only approved acute medical treatment of ischemic stroke is tissue plasminogen activator (tPA), but its effectiveness is greatly predicated upon early administration of the drug. There is, therefore, an urgent need to find new therapeutic options for acute stroke. Areas covered: In this review, we summarize the role of Rho-associated coiled-coil containing kinase (ROCK) and its potential as a therapeutic target in stroke pathophysiology. ROCK is a major regulator of cell contractility, motility, and proliferation. Many of these ROCK-mediated processes in endothelial cells, vascular smooth muscle cells, pericytes, astrocytes, glia, neurons, leukocytes, and platelets are important in stroke pathophysiology, and the inhibition of such processes could improve stroke outcome. Expert commentary: ROCK is a potential therapeutic target for cardiovascular disease and ROCK inhibitors have already been approved for human use in Japan and China for the treatment of acute stroke. Further studies are needed to determine the role of ROCK isoforms in the pathophysiology of cerebral ischemia and whether there are further therapeutic benefits with selective ROCK inhibitors.

BRAF inhibitors suppress apoptosis through off-target inhibition of JNK signaling

PubMed Central

Vin, Harina; Ojeda, Sandra S; Ching, Grace; Leung, Marco L; Chitsazzadeh, Vida; Dwyer, David W; Adelmann, Charles H; Restrepo, Monica; Richards, Kristen N; Stewart, Larissa R; Du, Lili; Ferguson, Scarlett B; Chakravarti, Deepavali; Ehrenreiter, Karin; Baccarini, Manuela; Ruggieri, Rosamaria; Curry, Jonathan L; Kim, Kevin B; Ciurea, Ana M; Duvic, Madeleine; Prieto, Victor G; Ullrich, Stephen E; Dalby, Kevin N; Flores, Elsa R; Tsai, Kenneth Y

2013-01-01

Vemurafenib and dabrafenib selectively inhibit the v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) kinase, resulting in high response rates and increased survival in melanoma. Approximately 22% of individuals treated with vemurafenib develop cutaneous squamous cell carcinoma (cSCC) during therapy. The prevailing explanation for this is drug-induced paradoxical ERK activation, resulting in hyperproliferation. Here we show an unexpected and novel effect of vemurafenib/PLX4720 in suppressing apoptosis through the inhibition of multiple off-target kinases upstream of c-Jun N-terminal kinase (JNK), principally ZAK. JNK signaling is suppressed in multiple contexts, including in cSCC of vemurafenib-treated patients, as well as in mice. Expression of a mutant ZAK that cannot be inhibited reverses the suppression of JNK activation and apoptosis. Our results implicate suppression of JNK-dependent apoptosis as a significant, independent mechanism that cooperates with paradoxical ERK activation to induce cSCC, suggesting broad implications for understanding toxicities associated with BRAF inhibitors and for their use in combination therapies. DOI: http://dx.doi.org/10.7554/eLife.00969.001 PMID:24192036

WNT5A enhances resistance of melanoma cells to targeted BRAF inhibitors

PubMed Central

Anastas, Jamie N.; Kulikauskas, Rima M.; Tamir, Tigist; Rizos, Helen; Long, Georgina V.; von Euw, Erika M.; Yang, Pei-Tzu; Chen, Hsiao-Wang; Haydu, Lauren; Toroni, Rachel A.; Lucero, Olivia M.; Chien, Andy J.; Moon, Randall T.

2014-01-01

About half of all melanomas harbor a mutation that results in a constitutively active BRAF kinase mutant (BRAFV600E/K) that can be selectively inhibited by targeted BRAF inhibitors (BRAFis). While patients treated with BRAFis initially exhibit measurable clinical improvement, the majority of patients eventually develop drug resistance and relapse. Here, we observed marked elevation of WNT5A in a subset of tumors from patients exhibiting disease progression on BRAFi therapy. WNT5A transcript and protein were also elevated in BRAFi-resistant melanoma cell lines generated by long-term in vitro treatment with BRAFi. RNAi-mediated reduction of endogenous WNT5A in melanoma decreased cell growth, increased apoptosis in response to BRAFi challenge, and decreased the activity of prosurvival AKT signaling. Conversely, overexpression of WNT5A promoted melanoma growth, tumorigenesis, and activation of AKT signaling. Similarly to WNT5A knockdown, knockdown of the WNT receptors FZD7 and RYK inhibited growth, sensitized melanoma cells to BRAFi, and reduced AKT activation. Together, these findings suggest that chronic BRAF inhibition elevates WNT5A expression, which promotes AKT signaling through FZD7 and RYK, leading to increased growth and therapeutic resistance. Furthermore, increased WNT5A expression in BRAFi-resistant melanomas correlates with a specific transcriptional signature, which identifies potential therapeutic targets to reduce clinical BRAFi resistance. PMID:24865425

Probing plasmodesmata function with biochemical inhibitors.

PubMed

White, Rosemary G

2015-01-01

To investigate plasmodesmata (PD) function, a useful technique is to monitor the effect on cell-to-cell transport of applying an inhibitor of a physiological process, protein, or other cell component of interest. Changes in PD transport can then be monitored in one of several ways, most commonly by measuring the cell-to-cell movement of fluorescent tracer dyes or of free fluorescent proteins. Effects on PD structure can be detected in thin sections of embedded tissue observed using an electron microscope, most commonly a Transmission Electron Microscope (TEM). This chapter outlines commonly used inhibitors, methods for treating different tissues, how to detect altered cell-to-cell transport and PD structure, and important caveats.

Systems proteomic analysis reveals that clusterin and tissue inhibitor of metalloproteinases 3 increase in leptomeningeal arteries affected by cerebral amyloid angiopathy.

PubMed

Manousopoulou, A; Gatherer, M; Smith, C; Nicoll, J A R; Woelk, C H; Johnson, M; Kalaria, R; Attems, J; Garbis, S D; Carare, R O

2017-10-01

Amyloid beta (Aβ) accumulation in the walls of leptomeningeal arteries as cerebral amyloid angiopathy (CAA) is a major feature of Alzheimer's disease. In this study, we used global quantitative proteomic analysis to examine the hypothesis that the leptomeningeal arteries derived from patients with CAA have a distinct endophenotypic profile compared to those from young and elderly controls. Freshly dissected leptomeningeal arteries from the Newcastle Brain Tissue Resource and Edinburgh Sudden Death Brain Bank from seven elderly (82.9 ± 7.5 years) females with severe capillary and arterial CAA, as well as seven elderly (88.3 ± 8.6 years) and five young (45.4 ± 3.9 years) females without CAA were used in this study. Arteries from four patients with CAA, two young and two elderly controls were individually analysed using quantitative proteomics. Key proteomic findings were then validated using immunohistochemistry. Bioinformatics interpretation of the results showed a significant enrichment of the immune response/classical complement and extracellular matrix remodelling pathways (P < 0.05) in arteries affected by CAA vs. those from young and elderly controls. Clusterin (apolipoprotein J) and tissue inhibitor of metalloproteinases-3 (TIMP3), validated using immunohistochemistry, were shown to co-localize with Aβ and to be up-regulated in leptomeningeal arteries from CAA patients compared to young and elderly controls. Global proteomic profiling of brain leptomeningeal arteries revealed that clusterin and TIMP3 increase in leptomeningeal arteries affected by CAA. We propose that clusterin and TIMP3 could facilitate perivascular clearance and may serve as novel candidate therapeutic targets for CAA. © 2016 The Authors. Neuropathology and Applied Neurobiology published by John Wiley & Sons Ltd on behalf of British Neuropathological Society.

Therapeutic strategies for metabolic diseases: Small-molecule diacylglycerol acyltransferase (DGAT) inhibitors.

PubMed

Naik, Ravi; Obiang-Obounou, Brice W; Kim, Minkyoung; Choi, Yongseok; Lee, Hyun Sun; Lee, Kyeong

2014-11-01

Metabolic diseases such as atherogenic dyslipidemia, hepatic steatosis, obesity, and type II diabetes are emerging as major global health problems. Acyl-CoA:diacylglycerol acyltransferase (DGAT) is responsible for catalyzing the final reaction in the glycerol phosphate pathway of triglycerol synthesis. It has two isoforms, DGAT-1 and DGAT-2, which are widely expressed and present in white adipose tissue. DGAT-1 is most highly expressed in the small intestine, whereas DGAT-2 is primarily expressed in the liver. Therefore, the selective inhibition of DGAT-1 has become an attractive target with growing potential for the treatment of obesity and type II diabetes. Furthermore, DGAT-2 has been suggested as a new target for the treatment of DGAT-2-related liver diseases including hepatic steatosis, hepatic injury, and fibrosis. In view the discovery of drugs that target DGAT, herein we attempt to provide insight into the scope and further reasons for optimization of DGAT inhibitors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Glycogen phosphorylase as a target for type 2 diabetes: synthetic, biochemical, structural and computational evaluation of novel N-acyl-N´-(β-D-glucopyranosyl) urea inhibitors.

PubMed

Kantsadi, Anastassia L; Parmenopoulou, Vanessa; Bakalov, Dimitar N; Snelgrove, Laura; Stravodimos, George A; Chatzileontiadou, Demetra S M; Manta, Stella; Panagiotopoulou, Angeliki; Hayes, Joseph M; Komiotis, Dimitri; Leonidas, Demetres D

2015-01-01

Glycogen phosphorylase (GP), a validated target for the development of anti-hyperglycaemic agents, has been targeted for the design of novel glycopyranosylamine inhibitors. Exploiting the two most potent inhibitors from our previous study of N-acyl-β-D-glucopyranosylamines (Parmenopoulou et al., Bioorg. Med. Chem. 2014, 22, 4810), we have extended the linking group to -NHCONHCO- between the glucose moiety and the aliphatic/aromatic substituent in the GP catalytic site β-cavity. The N-acyl-N´-(β-D-glucopyranosyl) urea inhibitors were synthesized and their efficiency assessed by biochemical methods, revealing inhibition constant values of 4.95 µM and 2.53 µM. Crystal structures of GP in complex with these inhibitors were determined and analyzed, providing data for further structure based design efforts. A novel Linear Response - Molecular Mechanics Coulomb Surface Area (LR-MM-CBSA) method has been developed which relates predicted and experimental binding free energies for a training set of N-acyl-N´-(β-D-glucopyranosyl) urea ligands with a correlation coefficient R(2) of 0.89 and leave-one-out cross-validation (LOO-cv) Q(2) statistic of 0.79. The method has significant applications to direct future lead optimization studies, where ligand entropy loss on binding is revealed as a key factor to be considered. ADMET property predictions revealed that apart from potential permeability issues, the synthesized N-acyl-N´-(β-D-glucopyranosyl) urea inhibitors have drug-like potential without any toxicity warnings.

A human tissue-based functional assay platform to evaluate the immune function impact of small molecule inhibitors that target the immune system.

PubMed

St Pierre, Cristina; Guo, Jane; Shin, John D; Engstrom, Laura W; Lee, Hyun-Hee; Herbert, Alan; Surdi, Laura; Baker, James; Salmon, Michael; Shah, Sanjiv; Ellis, J Michael; Houshyar, Hani; Crackower, Michael A; Kleinschek, Melanie A; Jones, Dallas C; Hicks, Alexandra; Zaller, Dennis M; Alves, Stephen E; Ramadas, Ravisankar A

2017-01-01

While the immune system is essential for the maintenance of the homeostasis, health and survival of humans, aberrant immune responses can lead to chronic inflammatory and autoimmune disorders. Pharmacological modulation of drug targets in the immune system to ameliorate disease also carry a risk of immunosuppression that could lead to adverse outcomes. Therefore, it is important to understand the 'immune fingerprint' of novel therapeutics as they relate to current and, clinically used immunological therapies to better understand their potential therapeutic benefit as well as immunosuppressive ability that might lead to adverse events such as infection risks and cancer. Since the mechanistic investigation of pharmacological modulators in a drug discovery setting is largely compound- and mechanism-centric but not comprehensive in terms of immune system impact, we developed a human tissue based functional assay platform to evaluate the impact of pharmacological modulators on a range of innate and adaptive immune functions. Here, we demonstrate that it is possible to generate a qualitative and quantitative immune system impact of pharmacological modulators, which might help better understand and predict the benefit-risk profiles of these compounds in the treatment of immune disorders.

MMpI: A WideRange of Available Compounds of Matrix Metalloproteinase Inhibitors

PubMed Central

Muvva, Charuvaka; Patra, Sanjukta; Venkatesan, Subramanian

2016-01-01

Matrix metalloproteinases (MMPs) are a family of zinc-dependent proteinases involved in the regulation of the extracellular signaling and structural matrix environment of cells and tissues. MMPs are considered as promising targets for the treatment of many diseases. Therefore, creation of database on the inhibitors of MMP would definitely accelerate the research activities in this area due to its implication in above-mentioned diseases and associated limitations in the first and second generation inhibitors. In this communication, we report the development of a new MMpI database which provides resourceful information for all researchers working in this field. It is a web-accessible, unique resource that contains detailed information on the inhibitors of MMP including small molecules, peptides and MMP Drug Leads. The database contains entries of ~3000 inhibitors including ~72 MMP Drug Leads and ~73 peptide based inhibitors. This database provides the detailed molecular and structural details which are necessary for the drug discovery and development. The MMpI database contains physical properties, 2D and 3D structures (mol2 and pdb format files) of inhibitors of MMP. Other data fields are hyperlinked to PubChem, ChEMBL, BindingDB, DrugBank, PDB, MEROPS and PubMed. The database has extensive searching facility with MMpI ID, IUPAC name, chemical structure and with the title of research article. The MMP inhibitors provided in MMpI database are optimized using Python-based Hierarchical Environment for Integrated Xtallography (Phenix) software. MMpI Database is unique and it is the only public database that contains and provides the complete information on the inhibitors of MMP. Database URL: http://clri.res.in/subramanian/databases/mmpi/index.php. PMID:27509041

Targeted therapies in cancer - challenges and chances offered by newly developed techniques for protein analysis in clinical tissues

PubMed Central

Malinowsky, K; Wolff, C; Gündisch, S; Berg, D; Becker, KF

2011-01-01

In recent years, new anticancer therapies have accompanied the classical approaches of surgery and radio- and chemotherapy. These new forms of treatment aim to inhibit specific molecular targets namely altered or deregulated proteins, which offer the possibility of individualized therapies. The specificity and efficiency of these new approaches, however, bring about a number of challenges. First of all, it is essential to specifically identify and quantify protein targets in tumor tissues for the reasonable use of such targeted therapies. Additionally, it has become even more obvious in recent years that the presence of a target protein is not always sufficient to predict the outcome of targeted therapies. The deregulation of downstream signaling molecules might also play an important role in the success of such therapeutic approaches. For these reasons, the analysis of tumor-specific protein expression profiles prior to therapy has been suggested as the most effective way to predict possible therapeutic results. To further elucidate signaling networks underlying cancer development and to identify new targets, it is necessary to implement tools that allow the rapid, precise, inexpensive and simultaneous analysis of many network components while requiring only a small amount of clinical material. Reverse phase protein microarray (RPPA) is a promising technology that meets these requirements while enabling the quantitative measurement of proteins. Together with recently developed protocols for the extraction of proteins from formalin-fixed, paraffin-embedded (FFPE) tissues, RPPA may provide the means to quantify therapeutic targets and diagnostic markers in the near future and reliably screen for new protein targets. With the possibility to quantitatively analyze DNA, RNA and protein from a single FFPE tissue sample, the methods are available for integrated patient profiling at all levels of gene expression, thus allowing optimal patient stratification for