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Sample records for inhibitor series targeting

  1. Tyrosine kinase inhibitors: Multi-targeted or single-targeted?

    Science.gov (United States)

    Broekman, Fleur; Giovannetti, Elisa; Peters, Godefridus J

    2011-02-10

    Since in most tumors multiple signaling pathways are involved, many of the inhibitors in clinical development are designed to affect a wide range of targeted kinases. The most important tyrosine kinase families in the development of tyrosine kinase inhibitors are the ABL, SCR, platelet derived growth factor, vascular endothelial growth factor receptor and epidermal growth factor receptor families. Both multi-kinase inhibitors and single-kinase inhibitors have advantages and disadvantages, which are related to potential resistance mechanisms, pharmacokinetics, selectivity and tumor environment. In different malignancies various tyrosine kinases are mutated or overexpressed and several resistance mechanisms exist. Pharmacokinetics is influenced by interindividual differences and differs for two single targeted inhibitors or between patients treated by the same tyrosine kinase inhibitor. Different tyrosine kinase inhibitors have various mechanisms to achieve selectivity, while differences in gene expression exist between tumor and stromal cells. Considering these aspects, one type of inhibitor can generally not be preferred above the other, but will depend on the specific genetic constitution of the patient and the tumor, allowing personalized therapy. The most effective way of cancer treatment by using tyrosine kinase inhibitors is to consider each patient/tumor individually and to determine the strategy that specifically targets the consequences of altered (epi)genetics of the tumor. This strategy might result in treatment by a single multi kinase inhibitor for one patient, but in treatment by a couple of single kinase inhibitors for other patients.

  2. Kinase inhibitors can produce off-target effects and activate linked pathways by retroactivity

    Directory of Open Access Journals (Sweden)

    Wynn Michelle L

    2011-10-01

    Full Text Available Abstract Background It has been shown in experimental and theoretical work that covalently modified signaling cascades naturally exhibit bidirectional signal propagation via a phenomenon known as retroactivity. An important consequence of retroactivity, which arises due to enzyme sequestration in covalently modified signaling cascades, is that a downstream perturbation can produce a response in a component upstream of the perturbation without the need for explicit feedback connections. Retroactivity may, therefore, play an important role in the cellular response to a targeted therapy. Kinase inhibitors are a class of targeted therapies designed to interfere with a specific kinase molecule in a dysregulated signaling pathway. While extremely promising as anti-cancer agents, kinase inhibitors may produce undesirable off-target effects by non-specific interactions or pathway cross-talk. We hypothesize that targeted therapies such as kinase inhibitors can produce off-target effects as a consequence of retroactivity alone. Results We used a computational model and a series of simple signaling motifs to test the hypothesis. Our results indicate that within physiologically and therapeutically relevant ranges for all parameters, a targeted inhibitor can naturally induce an off-target effect via retroactivity. The kinetics governing covalent modification cycles in a signaling network were more important for propagating an upstream off-target effect in our models than the kinetics governing the targeted therapy itself. Our results also reveal the surprising and crucial result that kinase inhibitors have the capacity to turn "on" an otherwise "off" parallel cascade when two cascades share an upstream activator. Conclusions A proper and detailed characterization of a pathway's structure is important for identifying the optimal protein to target as well as what concentration of the targeted therapy is required to modulate the pathway in a safe and effective

  3. Tricyclic GyrB/ParE (TriBE inhibitors: a new class of broad-spectrum dual-targeting antibacterial agents.

    Directory of Open Access Journals (Sweden)

    Leslie W Tari

    Full Text Available 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.

  4. Discovery and Biological Evaluation of a Series of Pyrrolo[2,3-b]pyrazines as Novel FGFR Inhibitors.

    Science.gov (United States)

    Zhang, Yan; Liu, Hongchun; Zhang, Zhen; Wang, Ruifeng; Liu, Tongchao; Wang, Chaoyun; Ma, Yuchi; Ai, Jing; Zhao, Dongmei; Shen, Jingkang; Xiong, Bing

    2017-04-05

    Abnormality of fibroblast growth factor receptor (FGFR)-mediated signaling pathways were frequently found in various human malignancies, making FGFRs hot targets for cancer treatment. To address the consistent need for a new chemotype of FGFR inhibitors, here, we started with a hit structure identified from our internal hepatocyte growth factor receptor (also called c-Met) inhibitor project, and conducted a chemical optimization. After exploring three parts of the hit compound, we finally discovered a new series of pyrrolo[2,3- b ]pyrazine FGFR inhibitors, which contain a novel scaffold and unique molecular shape. We believe that our findings can help others to further develop selective FGFR inhibitors.

  5. Discovery and Biological Evaluation of a Series of Pyrrolo[2,3-b]pyrazines as Novel FGFR Inhibitors

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2017-04-01

    Full Text Available Abnormality of fibroblast growth factor receptor (FGFR-mediated signaling pathways were frequently found in various human malignancies, making FGFRs hot targets for cancer treatment. To address the consistent need for a new chemotype of FGFR inhibitors, here, we started with a hit structure identified from our internal hepatocyte growth factor receptor (also called c-Met inhibitor project, and conducted a chemical optimization. After exploring three parts of the hit compound, we finally discovered a new series of pyrrolo[2,3-b]pyrazine FGFR inhibitors, which contain a novel scaffold and unique molecular shape. We believe that our findings can help others to further develop selective FGFR inhibitors.

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

    Science.gov (United States)

    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

  7. Design and optimization of a series of 1-sulfonylpyrazolo[4,3-b]pyridines as selective c-Met inhibitors.

    Science.gov (United States)

    Ma, Yuchi; Sun, Guangqiang; Chen, Danqi; Peng, Xia; Chen, Yue-Lei; Su, Yi; Ji, Yinchun; Liang, Jin; Wang, Xin; Chen, Lin; Ding, Jian; Xiong, Bing; Ai, Jing; Geng, Meiyu; Shen, Jingkang

    2015-03-12

    c-Met has emerged as an attractive target for targeted cancer therapy because of its abnormal activation in many cancer cells. To identify high potent and selective c-Met inhibitors, we started with profiling the potency and in vitro metabolic stability of a reported hit 7. By rational design, a novel sulfonylpyrazolo[4,3-b]pyridine 9 with improved DMPK properties was discovered. Further elaboration of π-π stacking interactions and solvent accessible polar moieties led to a series of highly potent and selective type I c-Met inhibitors. On the basis of in vitro and in vivo pharmacological and pharmacokinetics studies, compound 46 was selected as a preclinical candidate for further anticancer drug development.

  8. Antimalarial activity of HIV-1 protease inhibitor in chromone series.

    Science.gov (United States)

    Lerdsirisuk, Pradith; Maicheen, Chirattikan; Ungwitayatorn, Jiraporn

    2014-12-01

    Increasing parasite resistance to nearly all available antimalarial drugs becomes a serious problem to human health and necessitates the need to continue the search for new effective drugs. Recent studies have shown that clinically utilized HIV-1 protease (HIV-1 PR) inhibitors can inhibit the in vitro and in vivo growth of Plasmodium falciparum. In this study, a series of chromone derivatives possessing HIV-1 PR inhibitory activity has been tested for antimalarial activity against P. falciparum (K1 multi-drug resistant strain). Chromone 15, the potent HIV-1 PR inhibitor (IC50=0.65μM), was found to be the most potent antimalarial compound with IC50=0.95μM while primaquine and tafenoquine showed IC50=2.41 and 1.95μM, respectively. Molecular docking study of chromone compounds against plasmepsin II, an aspartic protease enzyme important in hemoglobin degradation, revealed that chromone 15 exhibited the higher binding affinity (binding energy=-13.24kcal/mol) than the known PM II inhibitors. Thus, HIV-1 PR inhibitor in chromone series has the potential to be a new class of antimalarial agent. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Investigation of naphthofuran moiety as potential dual inhibitor against BACE-1 and GSK-3β: molecular dynamics simulations, binding energy, and network analysis to identify first-in-class dual inhibitors against Alzheimer's disease.

    Science.gov (United States)

    Kumar, Akhil; Srivastava, Gaurava; Srivastava, Swati; Verma, Seema; Negi, Arvind S; Sharma, Ashok

    2017-08-01

    BACE-1 and GSK-3β are potential therapeutic drug targets for Alzheimer's disease. Recently, both the targets received attention for designing dual inhibitors for Alzheimer's disease. Until now, only two-scaffold triazinone and curcumin have been reported as BACE-1 and GSK-3β dual inhibitors. Docking, molecular dynamics, clustering, binding energy, and network analysis of triazinone derivatives with BACE-1 and GSK-3β was performed to get molecular insight into the first reported dual inhibitor. Further, we designed and evaluated a naphthofuran series for its ability to inhibit BACE-1 and GSK-3β with the computational approaches. Docking study of naphthofuran series showed a good binding affinity towards both the targets. Molecular dynamics, binding energy, and network analysis were performed to compare their binding with the targets and amino acids responsible for binding. Naphthofuran series derivatives showed good interaction within the active site residues of both of the targets. Hydrogen bond occupancy and binding energy suggested strong binding with the targets. Dual-inhibitor binding was mostly governed by the hydrophobic interactions for both of the targets. Per residue energy decomposition and network analysis identified the key residues involved in the binding and inhibiting BACE-1 and GSK-3β. The results indicated that naphthofuran series derivative 11 may be a promising first-in-class dual inhibitor against BACE-1 and GSK-3β. This naphthofuran series may be further explored to design better dual inhibitors. Graphical abstract Naphthofuran derivative as a dual inhibitor for BACE-1 and GSK-3β.

  10. Novel guanidine-based inhibitors of inosine monophosphate dehydrogenase.

    Science.gov (United States)

    Iwanowicz, Edwin J; Watterson, Scott H; Liu, Chunjian; Gu, Henry H; Mitt, Toomas; Leftheris, Katerina; Barrish, Joel C; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Hollenbaugh, Diane L

    2002-10-21

    A series of novel guanidine-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. IMPDH catalyzes the rate determining step in guanine nucleotide biosynthesis and is a target for anticancer, immunosuppressive and antiviral therapy. The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for this new series of inhibitors is given.

  11. Novel inhibitors of IMPDH: a highly potent and selective quinolone-based series.

    Science.gov (United States)

    Watterson, Scott H; Carlsen, Marianne; Dhar, T G Murali; Shen, Zhongqi; Pitts, William J; Guo, Junqing; Gu, Henry H; Norris, Derek; Chorba, John; Chen, Ping; Cheney, Daniel; Witmer, Mark; Fleener, Catherine A; Rouleau, Katherine; Townsend, Robert; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2003-02-10

    A series of novel quinolone-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are described.

  12. DMPD: Ubiquitin: tool and target for intracellular NF-kappaB inhibitors. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16982211 Ubiquitin: tool and target for intracellular NF-kappaB inhibitors. Wullaer...vg) (.html) (.csml) Show Ubiquitin: tool and target for intracellular NF-kappaB inhibitors. PubmedID 1698221...1 Title Ubiquitin: tool and target for intracellular NF-kappaB inhibitors. Author

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

    Science.gov (United States)

    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.

  14. Epitope-Targeting of Tertiary Protein Structure Enables Target-Guided Synthesis of a Potent in Cell Inhibitor of Botulinum Neurotoxin**

    OpenAIRE

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

    2015-01-01

    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 ...

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

    Science.gov (United States)

    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.

  16. Lead optimization of a pyridine-carboxamide series as DGAT-1 inhibitors.

    Science.gov (United States)

    Ting, Pauline C; Lee, Joe F; Zorn, Nicolas; Kim, Hyunjin M; Aslanian, Robert G; Lin, Mingxiang; Smith, Michelle; Walker, Scott S; Cook, John; Van Heek, Margaret; Lachowicz, Jean

    2013-02-15

    The structure-activity relationship studies of a novel series of carboxylic acid derivatives of pyridine-carboxamides as DGAT-1 inhibitors is described. The optimization of the initial lead compound 6 based on in vitro and in vivo activity led to the discovery of key compounds 10j and 17h. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  18. 3-cyanoindole-based inhibitors of inosine monophosphate dehydrogenase: synthesis and initial structure-activity relationships.

    Science.gov (United States)

    Dhar, T G Murali; Shen, Zhongqi; Gu, Henry H; Chen, Ping; Norris, Derek; Watterson, Scott H; Ballentine, Shelley K; Fleener, Catherine A; Rouleau, Katherine A; Barrish, Joel C; Townsend, Robert; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2003-10-20

    A series of novel small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH), based upon a 3-cyanoindole core, were explored. IMPDH catalyzes the rate determining step in guanine nucleotide biosynthesis and is a target for anticancer, immunosuppressive and antiviral therapy. The synthesis and the structure-activity relationships (SAR), derived from in vitro studies, for this new series of inhibitors is given.

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

    International Nuclear Information System (INIS)

    Han, Yu Kyeong; Lee, Jae Ho; Park, Ga-Young; Chun, Sung Hak; Han, Jeong Yun; Kim, Sung Dae; Lee, Janet; Lee, Chang-Woo; Yang, Kwangmo; Lee, Chang Geun

    2013-01-01

    Highlights: ► A CDK4 inhibitor may be used for breast cancer stem cell-targeted therapy. ► The CDK4 inhibitor differentiated the cancer stem cell population (CD24 − /CD44 + ) 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. 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

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

    Science.gov (United States)

    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.

  1. A new series of HAPs as anti-HBV agents targeting at capsid assembly.

    Science.gov (United States)

    Yang, Xiu-yan; Xu, Xiao-qian; Guan, Hua; Wang, Li-li; Wu, Qin; Zhao, Guo-ming; Li, Song

    2014-09-01

    A series of novel Heteroaryldihydropyrimidines (HAPs) derivatives were designed and synthesized as potent inhibitors of HBV capsid assembly. These compounds were prepared from efforts to optimize an earlier series of HAPs, and compounds Mo1, Mo7, Mo8, Mo10, Mo12, and Mo13 demonstrated potent inhibition of HBV DNA replication at submicromolar range. Copyright © 2014. Published by Elsevier Ltd.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Catarina Oliveira

    2018-04-01

    Full Text Available 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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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 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.

  6. Biochemical evaluation of a series of synthetic chalcone and hydrazide derivatives as novel inhibitors of cruzain from Trypanosoma cruzi

    Energy Technology Data Exchange (ETDEWEB)

    Borchhardt, Deise M.; Oliva, Glaucius; Andricopulo, Adriano D. [Universidade de Sao Paulo, Sao Carlos (USP), SP (Brazil). Centro de Biotecnologia Molecular Estrutural. Lab. de Quimica Medicinal e Computacional; Mascarello, Alessandra; Chiaradia, Louise Domeneghini; Nunes, Ricardo J.; Yunes, Rosendo A. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Centro de Ciencias Fisicas e Matematicas. Lab. Estrutura e Atividade

    2010-07-01

    Chagas' disease, a parasitic infection widely distributed throughout Latin America, is a major public health problem with devastating consequences in terms of human morbidity and mortality. The enzyme cruzain is the major cysteine protease from Trypanosoma cruzi, the etiologic agent of American trypanosomiasis or Chagas' disease, and has been selected as an attractive target for the development of novel trypanocidal drugs. In the present work, we describe the synthesis and inhibitory effects of a series of thirty-three chalcone and seven hydrazide derivatives against the enzyme cruzain from T. cruzi. Most of the compounds showed promising in vitro inhibition (IC{sub 50} values in the range of 20-60 {mu}M), which suggest the potential of these compounds as lead candidates for further development. Twelve compounds have not been reported before, and four of them (7, 13, 16 e 18) are among the most potent inhibitors of the series. (author)

  7. Potent nonnucleoside reverse transcriptase inhibitors target HIV-1 Gag-Pol.

    Directory of Open Access Journals (Sweden)

    Anna Figueiredo

    2006-11-01

    Full Text Available Nonnucleoside reverse transcriptase inhibitors (NNRTIs target HIV-1 reverse transcriptase (RT by binding to a pocket in RT that is close to, but distinct, from the DNA polymerase active site and prevent the synthesis of viral cDNA. NNRTIs, in particular, those that are potent inhibitors of RT polymerase activity, can also act as chemical enhancers of the enzyme's inter-subunit interactions. However, the consequences of this chemical enhancement effect on HIV-1 replication are not understood. Here, we show that the potent NNRTIs efavirenz, TMC120, and TMC125, but not nevirapine or delavirdine, inhibit the late stages of HIV-1 replication. These potent NNRTIs enhanced the intracellular processing of Gag and Gag-Pol polyproteins, and this was associated with a decrease in viral particle production from HIV-1-transfected cells. The increased polyprotein processing is consistent with premature activation of the HIV-1 protease by NNRTI-enhanced Gag-Pol multimerization through the embedded RT sequence. These findings support the view that Gag-Pol multimerization is an important step in viral assembly and demonstrate that regulation of Gag-Pol/Gag-Pol interactions is a novel target for small molecule inhibitors of HIV-1 production. Furthermore, these drugs can serve as useful probes to further understand processes involved in HIV-1 particle assembly and maturation.

  8. Escape from Human Immunodeficiency Virus Type 1 (HIV-1 Entry Inhibitors

    Directory of Open Access Journals (Sweden)

    Carol D. Weiss

    2012-12-01

    Full Text Available The human immunodeficiency virus (HIV enters cells through a series of molecular interactions between the HIV envelope protein and cellular receptors, thus providing many opportunities to block infection. Entry inhibitors are currently being used in the clinic, and many more are under development. Unfortunately, as is the case for other classes of antiretroviral drugs that target later steps in the viral life cycle, HIV can become resistant to entry inhibitors. In contrast to inhibitors that block viral enzymes in intracellular compartments, entry inhibitors interfere with the function of the highly variable envelope glycoprotein as it continuously adapts to changing immune pressure and available target cells in the extracellular environment. Consequently, pathways and mechanisms of resistance for entry inhibitors are varied and often involve mutations across the envelope gene. This review provides a broad overview of entry inhibitor resistance mechanisms that inform our understanding of HIV entry and the design of new inhibitors and vaccines.

  9. Targeting Alzheimer's disease by investigating previously unexplored chemical space surrounding the cholinesterase inhibitor donepezil

    CSIR Research Space (South Africa)

    Van Greunen, DG

    2017-02-01

    Full Text Available A series of twenty seven acetylcholinesterase inhibitors, as potential agents for the treatment of Alzheimer's disease, were designed and synthesised based upon previously unexplored chemical space surrounding the molecular skeleton of the drug...

  10. Cysteine Protease Inhibitors as Chemotherapy: Lessons from a Parasite Target

    Science.gov (United States)

    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.

  11. Mapping in vivo target interaction profiles of covalent inhibitors using chemical proteomics with label-free quantification.

    Science.gov (United States)

    van Rooden, Eva J; Florea, Bogdan I; Deng, Hui; Baggelaar, Marc P; van Esbroeck, Annelot C M; Zhou, Juan; Overkleeft, Herman S; van der Stelt, Mario

    2018-04-01

    Activity-based protein profiling (ABPP) has emerged as a valuable chemical proteomics method to guide the therapeutic development of covalent drugs by assessing their on-target engagement and off-target activity. We recently used ABPP to determine the serine hydrolase interaction landscape of the experimental drug BIA 10-2474, thereby providing a potential explanation for the adverse side effects observed with this compound. ABPP allows mapping of protein interaction landscapes of inhibitors in cells, tissues and animal models. Whereas our previous protocol described quantification of proteasome activity using stable-isotope labeling, this protocol describes the procedures for identifying the in vivo selectivity profile of covalent inhibitors with label-free quantitative proteomics. The optimization of our protocol for label-free quantification methods results in high proteome coverage and allows the comparison of multiple biological samples. We demonstrate our protocol by assessing the protein interaction landscape of the diacylglycerol lipase inhibitor DH376 in mouse brain, liver, kidney and testes. The stages of the protocol include tissue lysis, probe incubation, target enrichment, sample preparation, liquid chromatography-mass spectrometry (LC-MS) measurement, data processing and analysis. This approach can be used to study target engagement in a native proteome and to identify potential off targets for the inhibitor under investigation. The entire protocol takes at least 4 d, depending on the number of samples.

  12. A Holistic In silico Approach to Develop Novel Inhibitors Targeting ...

    African Journals Online (AJOL)

    Purpose: To design a dual inhibitor of natural origin capable of targeting ErbB1 and ErbB2 kinases for the treatment of lung cancer. Method: Advanced In silico drug designing techniques were explored in this study. Sequence and structure analysis of ErbB1 and ErbB2 was followed by three dimensional (3D) ...

  13. Design and Development of a Series of Potent and Selective Type II Inhibitors of CDK8

    Science.gov (United States)

    2016-01-01

    Using Sorafenib as a starting point, a series of potent and selective inhibitors of CDK8 was developed. When cocrystallized with CDK8 and cyclin C, these compounds exhibit a Type-II (DMG-out) binding mode. PMID:27326333

  14. Enhancement of vascular targeting by inhibitors of nitric oxide synthase

    International Nuclear Information System (INIS)

    Davis, Peter D.; Tozer, Gillian M.; Naylor, Matthew A.; Thomson, Peter; Lewis, Gemma; Hill, Sally A.

    2002-01-01

    Purpose: This study investigates the enhancement of the vascular targeting activity of the tubulin-binding agent combretastatin A4 phosphate (CA4P) by various inhibitors of nitric oxide synthases. Methods and Materials: The syngeneic tumors CaNT and SaS growing in CBA mice were used for this study. Reduction in perfused vascular volume was measured by injection of Hoechst 33342 24 h after drug administration. Necrosis (hematoxylin and eosin stain) was assessed also at 24 h after treatment. Combretastatin A4 phosphate was synthesized by a modification of the published procedure and the nitric oxide synthase inhibitors L-NNA, L-NMMA, L-NIO, L-NIL, S-MTC, S-EIT, AMP, AMT, and L-TC, obtained from commercial sources. Results: A statistically significant augmentation of the reduction in perfused vascular volume by CA4P in the CaNT tumor was observed with L-NNA, AMP, and AMT. An increase in CA4P-induced necrosis in the same tumor achieved significance with L-NNA, L-NMMA, L-NIL, and AMT. CA4P induced little necrosis in the SaS tumor, but combination with the inhibitors L-NNA, L-NMMA, L-NIO, S-EIT, and L-TC was effective. Conclusions: Augmentation of CA4P activity by nitric oxide synthase inhibitors of different structural classes supports a nitric oxide-related mechanism for this effect. L-NNA was the most effective inhibitor studied

  15. Side Effects of Nitrification Inhibitors on Non Target Microbial Processes in Soils

    OpenAIRE

    Johannes Carl Gottlieb Ottow; Gero Benckiser; Ferisman Tindaon

    2011-01-01

    Agricultural chemicals have been used extensively in modern agriculture and toxicological studies suggest a great potential for inducing undesirable effects on non target organisms. A model experiment was conducted in order to determine side effects of three nitrification inhibitors (NIs, 3,4dimethylpyrazolephosphate = DMPP, 4-Chlormethylpyrazole phosphate = ClMPP and dicyandiamide = DCD) on non target microbial processes in soils. Side effects and dose response curve of three NIs were quanti...

  16. Optimization of a pyrazole hit from FBDD into a novel series of indazoles as ketohexokinase inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuqing; Song, Fengbing; Kuo, Gee-Hong; Xiang, Amy; Gibbs, Alan C.; Abad, Marta C.; Sun, Weimei; Kuo, Lawrence C.; Sui, Zhihua (J); (J-PRD)

    2013-11-20

    A series of indazoles have been discovered as KHK inhibitors from a pyrazole hit identified through fragment-based drug discovery (FBDD). The optimization process guided by both X-ray crystallography and solution activity resulted in lead-like compounds with good pharmaceutical properties.

  17. A novel small molecule inhibitor of hepatitis C virus entry.

    Directory of Open Access Journals (Sweden)

    Carl J Baldick

    Full Text Available Small molecule inhibitors of hepatitis C virus (HCV are being developed to complement or replace treatments with pegylated interferons and ribavirin, which have poor response rates and significant side effects. Resistance to these inhibitors emerges rapidly in the clinic, suggesting that successful therapy will involve combination therapy with multiple inhibitors of different targets. The entry process of HCV into hepatocytes represents another series of potential targets for therapeutic intervention, involving viral structural proteins that have not been extensively explored due to experimental limitations. To discover HCV entry inhibitors, we utilized HCV pseudoparticles (HCVpp incorporating E1-E2 envelope proteins from a genotype 1b clinical isolate. Screening of a small molecule library identified a potent HCV-specific triazine inhibitor, EI-1. A series of HCVpp with E1-E2 sequences from various HCV isolates was used to show activity against all genotype 1a and 1b HCVpp tested, with median EC50 values of 0.134 and 0.027 µM, respectively. Time-of-addition experiments demonstrated a block in HCVpp entry, downstream of initial attachment to the cell surface, and prior to or concomitant with bafilomycin inhibition of endosomal acidification. EI-1 was equally active against cell-culture adapted HCV (HCVcc, blocking both cell-free entry and cell-to-cell transmission of virus. HCVcc with high-level resistance to EI-1 was selected by sequential passage in the presence of inhibitor, and resistance was shown to be conferred by changes to residue 719 in the carboxy-terminal transmembrane anchor region of E2, implicating this envelope protein in EI-1 susceptibility. Combinations of EI-1 with interferon, or inhibitors of NS3 or NS5A, resulted in additive to synergistic activity. These results suggest that inhibitors of HCV entry could be added to replication inhibitors and interferons already in development.

  18. Targeting Allostery with Avatars to Design Inhibitors Assessed by Cell Activity: Dissecting MRE11 Endo- and Exonuclease Activities.

    Science.gov (United States)

    Moiani, Davide; Ronato, Daryl A; Brosey, Chris A; Arvai, Andrew S; Syed, Aleem; Masson, Jean-Yves; Petricci, Elena; Tainer, John A

    2018-01-01

    For inhibitor design, as in most research, the best system is question dependent. We suggest structurally defined allostery to design specific inhibitors that target regions beyond active sites. We choose systems allowing efficient quality structures with conformational changes as optimal for structure-based design to optimize inhibitors. We maintain that evolutionarily related targets logically provide molecular avatars, where this Sanskrit term for descent includes ideas of functional relationships and of being a physical embodiment of the target's essential features without requiring high sequence identity. Appropriate biochemical and cell assays provide quantitative measurements, and for biomedical impacts, any inhibitor's activity should be validated in human cells. Specificity is effectively shown empirically by testing if mutations blocking target activity remove cellular inhibitor impact. We propose this approach to be superior to experiments testing for lack of cross-reactivity among possible related enzymes, which is a challenging negative experiment. As an exemplary avatar system for protein and DNA allosteric conformational controls, we focus here on developing separation-of-function inhibitors for meiotic recombination 11 nuclease activities. This was achieved not by targeting the active site but rather by geometrically impacting loop motifs analogously to ribosome antibiotics. These loops are neighboring the dimer interface and active site act in sculpting dsDNA and ssDNA into catalytically competent complexes. One of our design constraints is to preserve DNA substrate binding to geometrically block competing enzymes and pathways from the damaged site. We validate our allosteric approach to controlling outcomes in human cells by reversing the radiation sensitivity and genomic instability in BRCA mutant cells. © 2018 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  1. Optimization of a pyrazole hit from FBDD into a novel series of indazoles as ketohexokinase inhibitors.

    Science.gov (United States)

    Zhang, Xuqing; Song, Fengbing; Kuo, Gee-Hong; Xiang, Amy; Gibbs, Alan C; Abad, Marta C; Sun, Weimei; Kuo, Lawrence C; Sui, Zhihua

    2011-08-15

    A series of indazoles have been discovered as KHK inhibitors from a pyrazole hit identified through fragment-based drug discovery (FBDD). The optimization process guided by both X-ray crystallography and solution activity resulted in lead-like compounds with good pharmaceutical properties. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Development of antibody-based c-Met inhibitors for targeted cancer therapy

    Directory of Open Access Journals (Sweden)

    Lee D

    2015-02-01

    Full Text Available Dongheon Lee, Eun-Sil Sung, Jin-Hyung Ahn, Sungwon An, Jiwon Huh, Weon-Kyoo You Hanwha Chemical R&D Center, Biologics Business Unit, Daejeon, Republic of Korea Abstract: Signaling pathways mediated by receptor tyrosine kinases (RTKs and their ligands play important roles in the development and progression of human cancers, which makes RTK-mediated signaling pathways promising therapeutic targets in the treatment of cancer. Compared with small-molecule compounds, antibody-based therapeutics can more specifically recognize and bind to ligands and RTKs. Several antibody inhibitors of RTK-mediated signaling pathways, such as human epidermal growth factor receptor 2, vascular endothelial growth factor, epidermal growth factor receptor or vascular endothelial growth factor receptor 2, have been developed and are widely used to treat cancer patients. However, since the therapeutic options are still limited in terms of therapeutic efficacy and types of cancers that can be treated, efforts are being made to identify and evaluate novel RTK-mediated signaling pathways as targets for more efficacious cancer treatment. The hepatocyte growth factor/c-Met signaling pathway has come into the spotlight as a promising target for development of potent cancer therapeutic agents. Multiple antibody-based therapeutics targeting hepatocyte growth factor or c-Met are currently in preclinical or clinical development. This review focuses on the development of inhibitors of the hepatocyte growth factor/c-Met signaling pathway for cancer treatment, including critical issues in clinical development and future perspectives for antibody-based therapeutics. Keywords: hepatocyte growth factor, ligands, receptor tyrosine kinase, signaling pathway, therapeutic agent

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

    Science.gov (United States)

    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).

  4. P-glycoprotein targeted nanoscale drug carriers

    KAUST Repository

    Li, Wengang

    2013-02-01

    Multi-drug resistance (MDR) is a trend whereby tumor cells exposed to one cytotoxic agent develop cross-resistance to a range of structurally and functionally unrelated compounds. P -glycoprotein (P -gp) efflux pump is one of the mostly studied drug carrying processes that shuttle the drugs out of tumor cells. Thus, P -gp inhibitors have attracted a lot of attention as they can stop cancer drugs from being pumped out of target cells with the consumption of ATP. Using quantitive structure activity relationship (QSAR), we have successfully synthesized a series of novel P -gp inhibitors. The obtained dihydropyrroloquinoxalines series were fully characterized and then tested against bacterial and tumor assays with over-expressed P -gps. All compounds were bioactive especially compound 1c that had enhanced antibacterial activity. Furthermore, these compounds were utilized as targeting vectors to direct drug delivery vehicles such as silica nanoparticles (SNPs) to cancerous Hela cells with over expressed P -gps. Cell uptake studies showed a successful accumulation of these decorated SNPs in tumor cells compared to undecorated SNPs. The results obtained show that dihydropyrroloquinoxalines constitute a promising drug candidate for targeting cancers with MDR. Copyright © 2013 American Scientific Publishers All rights reserved.

  5. Structure-Based Design of a Novel Series of Potent, Selective Inhibitors of the Class I Phosphatidylinositol 3-Kinases

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Adrian L.; D’Angelo, Noel D.; Bo, Yunxin Y.; Booker, Shon K.; Cee, Victor J.; Herberich, Brad; Hong, Fang-Tsao; Jackson, Claire L.M.; Lanman, Brian A.; Liu, Longbin; Nishimura, Nobuko; Pettus, Liping H.; Reed, Anthony B.; Tadesse, Seifu; Tamayo, Nuria A.; Wurz, Ryan P.; Yang, Kevin; Andrews, Kristin L.; Whittington, Douglas A.; McCarter, John D.; Miguel, Tisha San; Zalameda, Leeanne; Jiang, Jian; Subramanian, Raju; Mullady, Erin L.; Caenepeel, Sean; Freeman, Daniel J.; Wang, Ling; Zhang, Nancy; Wu, Tian; Hughes, Paul E.; Norman, Mark H. (Amgen)

    2012-09-17

    A highly selective series of inhibitors of the class I phosphatidylinositol 3-kinases (PI3Ks) has been designed and synthesized. Starting from the dual PI3K/mTOR inhibitor 5, a structure-based approach was used to improve potency and selectivity, resulting in the identification of 54 as a potent inhibitor of the class I PI3Ks with excellent selectivity over mTOR, related phosphatidylinositol kinases, and a broad panel of protein kinases. Compound 54 demonstrated a robust PD-PK relationship inhibiting the PI3K/Akt pathway in vivo in a mouse model, and it potently inhibited tumor growth in a U-87 MG xenograft model with an activated PI3K/Akt pathway.

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

    Science.gov (United States)

    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.

  7. The role of multikinase inhibitors target therapy in radioiodine-resistant differentiated thyroid cancer

    Directory of Open Access Journals (Sweden)

    P O Rumyantsev

    2015-06-01

    Full Text Available About 5-15% of patients with differentiated thyroid cancer (DTC primary or within follow-up have had distant metastases or inoperable tumor mass that are resistant to radioiodine therapy as well as dramatically deteriorate survival prognosis. Other treatment modalities (radiotherapy, chemotherapy etc. also ineffective. Certain expectances are associated with target therapy with multikinase inhibitors with are selectively blocking onco-kinase molecular pathways. This review is devoted to analysis of those multikinase inhibitors which have been implemented in patients with radioiodine DTC. Comparative analysis of two most perspective multikinase inhibitors (sorafenib and lenvatinib with evaluation of efficacy and adverse effects was conducted. Both of them successfully underwent 3 rd phase of clinical trial and were recommended as treatment of choice in progressive radioiodine-resistant DTC patients.

  8. Structure-activity relationships of new cyanothiophene inhibitors of the essential peptidoglycan biosynthesis enzyme MurF.

    Science.gov (United States)

    Hrast, Martina; Turk, Samo; Sosič, Izidor; Knez, Damijan; Randall, Christopher P; Barreteau, Hélène; Contreras-Martel, Carlos; Dessen, Andréa; O'Neill, Alex J; Mengin-Lecreulx, Dominique; Blanot, Didier; Gobec, Stanislav

    2013-08-01

    Peptidoglycan is an essential component of the bacterial cell wall, and enzymes involved in its biosynthesis represent validated targets for antibacterial drug discovery. MurF catalyzes the final intracellular peptidoglycan biosynthesis step: the addition of D-Ala-D-Ala to the nucleotide precursor UDP-MurNAc-L-Ala-γ-D-Glu-meso-DAP (or L-Lys). As MurF has no human counterpart, it represents an attractive target for the development of new antibacterial drugs. Using recently published cyanothiophene inhibitors of MurF from Streptococcus pneumoniae as a starting point, we designed and synthesized a series of structurally related derivatives and investigated their inhibition of MurF enzymes from different bacterial species. Systematic structural modifications of the parent compounds resulted in a series of nanomolar inhibitors of MurF from S. pneumoniae and micromolar inhibitors of MurF from Escherichia coli and Staphylococcus aureus. Some of the inhibitors also show antibacterial activity against S. pneumoniae R6. These findings, together with two new co-crystal structures, represent an excellent starting point for further optimization toward effective novel antibacterials. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  9. Fabrication and testing of W7-X pre-series target elements

    International Nuclear Information System (INIS)

    Boscary, J; Boeswirth, B; Greuner, H; Grigull, P; Missirlian, M; Plankensteiner, A; Schedler, B; Friedrich, T; Schlosser, J; Streibl, B; Traxler, H

    2007-01-01

    The assembly of the highly-loaded target plates of the WENDELSTEIN 7-X (W7-X) divertor requires the fabrication of 890 target elements (TEs). The plasma facing material is made of CFC NB31 flat tiles bonded to a CuCrZr copper alloy water-cooled heat sink. The elements are designed to remove a stationary heat flux and power up to 10 MW m -2 and 100 kW, respectively. Before launching the serial fabrication, pre-series activities aimed at qualifying the design, the manufacturing route and the non-destructive examinations (NDEs). High heat flux (HHF) tests performed on full-scale pre-series TEs resulted in an improvement of the design of the bond between tiles and heat sink to reduce the stresses during operation. The consequence is the fabrication of additional pre-series TEs to be tested in the HHF facility GLADIS. NDEs of this bond based on thermography methods are developed to define the acceptance criteria suitable for serial fabrication

  10. Novel Small Molecule Inhibitors of Choline Kinase Identified by Fragment-Based Drug Discovery.

    Science.gov (United States)

    Zech, Stephan G; Kohlmann, Anna; Zhou, Tianjun; Li, Feng; Squillace, Rachel M; Parillon, Lois E; Greenfield, Matthew T; Miller, David P; Qi, Jiwei; Thomas, R Mathew; Wang, Yihan; Xu, Yongjin; Miret, Juan J; Shakespeare, William C; Zhu, Xiaotian; Dalgarno, David C

    2016-01-28

    Choline kinase α (ChoKα) is an enzyme involved in the synthesis of phospholipids and thereby plays key roles in regulation of cell proliferation, oncogenic transformation, and human carcinogenesis. Since several inhibitors of ChoKα display antiproliferative activity in both cellular and animal models, this novel oncogene has recently gained interest as a promising small molecule target for cancer therapy. Here we summarize our efforts to further validate ChoKα as an oncogenic target and explore the activity of novel small molecule inhibitors of ChoKα. Starting from weakly binding fragments, we describe a structure based lead discovery approach, which resulted in novel highly potent inhibitors of ChoKα. In cancer cell lines, our lead compounds exhibit a dose-dependent decrease of phosphocholine, inhibition of cell growth, and induction of apoptosis at low micromolar concentrations. The druglike lead series presented here is optimizable for improvements in cellular potency, drug target residence time, and pharmacokinetic parameters. These inhibitors may be utilized not only to further validate ChoKα as antioncogenic target but also as novel chemical matter that may lead to antitumor agents that specifically interfere with cancer cell metabolism.

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

    Directory of Open Access Journals (Sweden)

    Xinming Yang

    2018-01-01

    Full Text Available 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 (IC50 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.

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

    Science.gov (United States)

    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.

  13. Discovery and Biological Evaluation of a Series of Pyrrolo[2,3-b]pyrazines as Novel FGFR Inhibitors

    OpenAIRE

    Yan Zhang; Hongchun Liu; Zhen Zhang; Ruifeng Wang; Tongchao Liu; Chaoyun Wang; Yuchi Ma; Jing Ai; Dongmei Zhao; Jingkang Shen; Bing Xiong

    2017-01-01

    Abnormality of fibroblast growth factor receptor (FGFR)-mediated signaling pathways were frequently found in various human malignancies, making FGFRs hot targets for cancer treatment. To address the consistent need for a new chemotype of FGFR inhibitors, here, we started with a hit structure identified from our internal hepatocyte growth factor receptor (also called c-Met) inhibitor project, and conducted a chemical optimization. After exploring three parts of the hit compound, we finally dis...

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

    Science.gov (United States)

    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.

  15. Overcoming chemotherapy drug resistance by targeting inhibitors of apoptosis proteins (IAPs).

    Science.gov (United States)

    Rathore, Rama; McCallum, Jennifer E; Varghese, Elizabeth; Florea, Ana-Maria; Büsselberg, Dietrich

    2017-07-01

    Inhibitors of apoptosis (IAPs) are a family of proteins that play a significant role in the control of programmed cell death (PCD). PCD is essential to maintain healthy cell turnover within tissue but also to fight disease or infection. Uninhibited, IAPs can suppress apoptosis and promote cell cycle progression. Therefore, it is unsurprising that cancer cells demonstrate significantly elevated expression levels of IAPs, resulting in improved cell survival, enhanced tumor growth and subsequent metastasis. Therapies to target IAPs in cancer has garnered substantial scientific interest and as resistance to anti-cancer agents becomes more prevalent, targeting IAPs has become an increasingly attractive strategy to re-sensitize cancer cells to chemotherapies, antibody based-therapies and TRAIL therapy. Antagonism strategies to modulate the actions of XIAP, cIAP1/2 and survivin are the central focus of current research and this review highlights advances within this field with particular emphasis upon the development and specificity of second mitochondria-derived activator of caspase (SMAC) mimetics (synthetic analogs of endogenously expressed inhibitors of IAPs SMAC/DIABLO). While we highlight the potential of SMAC mimetics as effective single agent or combinatory therapies to treat cancer we also discuss the likely clinical implications of resistance to SMAC mimetic therapy, occasionally observed in cancer cell lines.

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

    Science.gov (United States)

    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.

  17. Discovery of Novel Tricyclic Heterocycles as Potent and Selective DPP-4 Inhibitors for the Treatment of Type 2 Diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wen-Lian; Hao, Jinsong; Domalski, Martin; Burnett, Duane A.; Pissarnitski, Dmitri; Zhao, Zhiqiang; Stamford, Andrew; Scapin, Giovanna; Gao, Ying-Duo; Soriano, Aileen; Kelly, Terri M.; Yao, Zuliang; Powles, Mary Ann; Chen, Shiying; Mei, Hong; Hwa, Joyce (Merck)

    2016-05-12

    In our efforts to develop second generation DPP-4 inhibitors, we endeavored to identify distinct structures with long-acting (once weekly) potential. Taking advantage of X-ray cocrystal structures of sitagliptin and other DPP-4 inhibitors, such as alogliptin and linagliptin bound to DPP-4, and aided by molecular modeling, we designed several series of heterocyclic compounds as initial targets. During their synthesis, an unexpected chemical transformation provided a novel tricyclic scaffold that was beyond our original design. Capitalizing on this serendipitous discovery, we have elaborated this scaffold into a very potent and selective DPP-4 inhibitor lead series, as highlighted by compound 17c.

  18. Peptidomimetic inhibitors of APC-Asef interaction block colorectal cancer migration.

    Science.gov (United States)

    Jiang, Haiming; Deng, Rong; Yang, Xiuyan; Shang, Jialin; Lu, Shaoyong; Zhao, Yanlong; Song, Kun; Liu, Xinyi; Zhang, Qiufen; Chen, Yu; Chinn, Y Eugene; Wu, Geng; Li, Jian; Chen, Guoqiang; Yu, Jianxiu; Zhang, Jian

    2017-09-01

    The binding of adenomatous polyposis coli (APC) to its receptor Asef relieves the negative intramolecular regulation of Asef and leads to aberrant cell migration in human colorectal cancer. Because of its crucial role in metastatic dissemination, the interaction between APC and Asef is an attractive target for anti-colorectal-cancer therapy. We rationally designed a series of peptidomimetics that act as potent inhibitors of the APC interface. Crystal structures and biochemical and cellular assays showed that the peptidomimetics in the APC pocket inhibited the migration of colorectal cells by disrupting APC-Asef interaction. By using the peptidomimetic inhibitor as a chemical probe, we found that CDC42 was the downstream GTPase involved in APC-stimulated Asef activation in colorectal cancer cells. Our work demonstrates the feasibility of exploiting APC-Asef interaction to regulate the migration of colorectal cancer cells, and provides what to our knowledge is the first class of protein-protein interaction inhibitors available for the development of cancer therapeutics targeting APC-Asef signaling.

  19. Pathway-based identification of biomarkers for targeted therapeutics: personalized oncology with PI3K pathway inhibitors.

    Science.gov (United States)

    Andersen, Jannik N; Sathyanarayanan, Sriram; Di Bacco, Alessandra; Chi, An; Zhang, Theresa; Chen, Albert H; Dolinski, Brian; Kraus, Manfred; Roberts, Brian; Arthur, William; Klinghoffer, Rich A; Gargano, Diana; Li, Lixia; Feldman, Igor; Lynch, Bethany; Rush, John; Hendrickson, Ronald C; Blume-Jensen, Peter; Paweletz, Cloud P

    2010-08-04

    Although we have made great progress in understanding the complex genetic alterations that underlie human cancer, it has proven difficult to identify which molecularly targeted therapeutics will benefit which patients. Drug-specific modulation of oncogenic signaling pathways in specific patient subpopulations can predict responsiveness to targeted therapy. Here, we report a pathway-based phosphoprofiling approach to identify and quantify clinically relevant, drug-specific biomarkers for phosphatidylinositol 3-kinase (PI3K) pathway inhibitors that target AKT, phosphoinositide-dependent kinase 1 (PDK1), and PI3K-mammalian target of rapamycin (mTOR). We quantified 375 nonredundant PI3K pathway-relevant phosphopeptides, all containing AKT, PDK1, or mitogen-activated protein kinase substrate recognition motifs. Of these phosphopeptides, 71 were drug-regulated, 11 of them by all three inhibitors. Drug-modulated phosphoproteins were enriched for involvement in cytoskeletal reorganization (filamin, stathmin, dynamin, PAK4, and PTPN14), vesicle transport (LARP1, VPS13D, and SLC20A1), and protein translation (S6RP and PRAS40). We then generated phosphospecific antibodies against selected, drug-regulated phosphorylation sites that would be suitable as biomarker tools for PI3K pathway inhibitors. As proof of concept, we show clinical translation feasibility for an antibody against phospho-PRAS40(Thr246). Evaluation of binding of this antibody in human cancer cell lines, a PTEN (phosphatase and tensin homolog deleted from chromosome 10)-deficient mouse prostate tumor model, and triple-negative breast tumor tissues showed that phospho-PRAS40(Thr246) positively correlates with PI3K pathway activation and predicts AKT inhibitor sensitivity. In contrast to phosphorylation of AKT(Thr308), the phospho-PRAS40(Thr246) epitope is highly stable in tissue samples and thus is ideal for immunohistochemistry. In summary, our study illustrates a rational approach for discovery of drug

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

    Science.gov (United States)

    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…

  1. Understanding binding affinity : A combined isothermal titration calorimetry/molecular dynamics study of the binding of a series of hydrophobically modified benzamidinium chloride inhibitors to trypsin

    NARCIS (Netherlands)

    Talhout, Reinskje; Villa, Alessandra; Mark, AE; Engberts, JBFN

    2003-01-01

    The binding of a series of p-alkylbenzamidinium chloride inhibitors to the serine proteinase trypsin over a range of temperatures has been studied using isothermal titration (micro)calorimetry and molecular dynamics simulation techniques. The inhibitors have small structural variations at the para

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

    Science.gov (United States)

    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.

  3. Targeting neuroblastoma stem cells with retinoic acid and proteasome inhibitor.

    Directory of Open Access Journals (Sweden)

    Barbara Hämmerle

    Full Text Available Neuroblastma cell lines contain a side-population of cells which express stemness markers. These stem-like cells may represent the potential underlying mechanism for resistance to conventional therapy and recurrence of neuroblastoma in patients.To develop novel strategies for targeting the side-population of neurobastomas, we analyzed the effects of 13-cis-retinoic acid (RA combined with the proteasome inhibitor MG132. The short-term action of the treatment was compared with effects after a 5-day recovery period during which both chemicals were withdrawn. RA induced growth arrest and differentiation of SH-SY5Y and SK-N-BE(2 neuroblastoma cell lines. Inhibition of the proteasome caused apoptosis in both cell lines, thus, revealing the critical role of this pathway in the regulated degradation of proteins involved in neuroblastoma proliferation and survival. The combination of RA with MG132 induced apoptosis in a dose-dependent manner, in addition to promoting G2/M arrest in treated cultures. Interestingly, expression of stem cell markers such as Nestin, Sox2, and Oct4 were reduced after the recovery period of combined treatment as compared with untreated cells or treated cells with either compound alone. Consistent with this, neurosphere formation was significantly impaired by the combined treatment of RA and MG132.Given that stem-like cells are associated with resistant to conventional therapy and are thought to be responsible for relapse, our results suggest that dual therapy of RA and proteasome inhibitor might be beneficial for targeting the side-population of cells associated residual disease in high-risk neuroblastoma.

  4. Anticancer actions of lysosomally targeted inhibitor, LCL521, of acid ceramidase.

    Science.gov (United States)

    Bai, Aiping; Mao, Cungui; Jenkins, Russell W; Szulc, Zdzislaw M; Bielawska, Alicja; Hannun, Yusuf A

    2017-01-01

    Acid ceramidase, which catalyzes ceramide hydrolysis to sphingosine and free fatty acid mainly in the lysosome, is being recognized as a potential therapeutic target for cancer. B13 is an effective and selective acid ceramidase inhibitor in vitro, but not as effective in cells due to poor access to the lysosomal compartment. In order to achieve targeting of B13 to the lysosome, we designed lysosomotropic N, N-dimethyl glycine (DMG)-conjugated B13 prodrug LCL521 (1,3-di-DMG-B13). Our previous results indicated the efficient delivery of B13 to the lysosome resulted in augmented effects of LCL521 on cellular acid ceramidase as evaluated by effects on substrate/product levels. Our current studies indicate that functionally, this translated into enhanced inhibition of cell proliferation. Moreover, there were greater synergistic effects of LCL521 with either ionizing radiation or Tamoxifen. Taken together, these results clearly indicate that compartmental targeting for the inhibition of acid ceramidase is an efficient and valuable therapeutic strategy.

  5. Development of a Series of Kynurenine 3-Monooxygenase Inhibitors Leading to a Clinical Candidate for the Treatment of Acute Pancreatitis.

    Science.gov (United States)

    Walker, Ann L; Ancellin, Nicolas; Beaufils, Benjamin; Bergeal, Marylise; Binnie, Margaret; Bouillot, Anne; Clapham, David; Denis, Alexis; Haslam, Carl P; Holmes, Duncan S; Hutchinson, Jonathan P; Liddle, John; McBride, Andrew; Mirguet, Olivier; Mowat, Christopher G; Rowland, Paul; Tiberghien, Nathalie; Trottet, Lionel; Uings, Iain; Webster, Scott P; Zheng, Xiaozhong; Mole, Damian J

    2017-04-27

    Recently, we reported a novel role for KMO in the pathogenesis of acute pancreatitis (AP). A number of inhibitors of kynurenine 3-monooxygenase (KMO) have previously been described as potential treatments for neurodegenerative conditions and particularly for Huntington's disease. However, the inhibitors reported to date have insufficient aqueous solubility relative to their cellular potency to be compatible with the intravenous (iv) dosing route required in AP. We have identified and optimized a novel series of high affinity KMO inhibitors with favorable physicochemical properties. The leading example is exquisitely selective, has low clearance in two species, prevents lung and kidney damage in a rat model of acute pancreatitis, and is progressing into preclinical development.

  6. Searching for Multi-Targeting Neurotherapeutics against Alzheimer’s: Discovery of Potent AChE-MAO B Inhibitors through the Decoration of the 2H-Chromen-2-one Structural Motif

    Directory of Open Access Journals (Sweden)

    Leonardo Pisani

    2016-03-01

    Full Text Available The need for developing real disease-modifying drugs against neurodegenerative syndromes, particularly Alzheimer’s disease (AD, shifted research towards reliable drug discovery strategies to unveil clinical candidates with higher therapeutic efficacy than single-targeting drugs. By following the multi-target approach, we designed and synthesized a novel class of dual acetylcholinesterase (AChE-monoamine oxidase B (MAO-B inhibitors through the decoration of the 2H-chromen-2-one skeleton. Compounds bearing a propargylamine moiety at position 3 displayed the highest in vitro inhibitory activities against MAO-B. Within this series, derivative 3h emerged as the most interesting hit compound, being a moderate AChE inhibitor (IC50 = 8.99 µM and a potent and selective MAO-B inhibitor (IC50 = 2.8 nM. Preliminary studies in human neuroblastoma SH-SY5Y cell lines demonstrated its low cytotoxicity and disclosed a promising neuroprotective effect at low doses (0.1 µM under oxidative stress conditions promoted by two mitochondrial toxins (oligomycin-A and rotenone. In a Madin-Darby canine kidney (MDCKII-MDR1 cell-based transport study, Compound 3h was able to permeate the BBB-mimicking monolayer and did not result in a glycoprotein-p (P-gp substrate, showing an efflux ratio = 0.96, close to that of diazepam.

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

    Science.gov (United States)

    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.

  8. Structural Insights into the Mechanisms of Action of Short-Peptide HIV-1 Fusion Inhibitors Targeting the Gp41 Pocket

    Directory of Open Access Journals (Sweden)

    Xiujuan Zhang

    2018-02-01

    Full Text Available The deep hydrophobic pocket of HIV-1 gp41 has been considered a drug target, but short-peptides targeting this site usually lack potent antiviral activity. By applying the M-T hook structure, we previously generated highly potent short-peptide fusion inhibitors that specifically targeted the pocket site, such as MT-SC22EK, HP23L, and LP-11. Here, the crystal structures of HP23L and LP-11 bound to the target mimic peptide N36 demonstrated the critical intrahelical and interhelical interactions, especially verifying that the hook-like conformation was finely adopted while the methionine residue was replaced by the oxidation-less prone residue leucine, and that addition of an extra glutamic acid significantly enhanced the binding and inhibitory activities. The structure of HP23L bound to N36 with two mutations (E49K and L57R revealed the critical residues and motifs mediating drug resistance and provided new insights into the mechanism of action of inhibitors. Therefore, the present data help our understanding for the structure-activity relationship (SAR of HIV-1 fusion inhibitors and facilitate the development of novel antiviral drugs.

  9. Design and synthesis of potent, orally-active DGAT-1 inhibitors containing a dioxino[2,3-d]pyrimidine core.

    Science.gov (United States)

    Dow, Robert L; Andrews, Melissa; Aspnes, Gary E; Balan, Gayatri; Michael Gibbs, E; Guzman-Perez, Angel; Karki, Kapil; Laperle, Jennifer L; Li, Jian-Cheng; Litchfield, John; Munchhof, Michael J; Perreault, Christian; Patel, Leena

    2011-10-15

    A novel series of potent DGAT-1 inhibitors was developed originating from the lactam-based clinical candidate PF-04620110. Incorporation of a dioxino[2,3-d]pyrimidine-based core afforded good alignment of pharmacophore features and resulted in improved passive permeability. Development of an efficient, homochiral synthesis of these targets facilitated confirmation of predictions regarding the stereochemical-dependence of DGAT-1 inhibition for this series. Compound 10 was shown to be a potent inhibitor of human DGAT-1 (10 nM) and to suppress triglyceride synthesis at oral doses of <3mg/kg. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  11. High heat flux tests of the WENDELSTEIN 7-X pre-series target elements

    International Nuclear Information System (INIS)

    Greuner, H.; Boeswirth, B.; Boscary, J.; Plankensteiner, A.; Schedler, B.

    2007-01-01

    The high heat flux (HHF) testing of WENDELSTEIN 7-X pre-series target elements is an indispensable step in the qualification of the manufacturing process. A set of 20 full scale pre-series elements was manufactured by PLANSEE SE to validate the materials and manufacturing technologies prior to the start of the series production. The HHF tests were performed in the ion beam test facility GLADIS. All actively water-cooled elements were tested for about 100 cycles at 10 MW/m 2 (10-15 s pulse duration). Several elements were loaded with even higher cycle numbers (up to 1000) and heat loads up to 24 MW/m 2 . Hot spots were, observed at the edges of several tiles during the HHF tests indicating local bonding problems of the CFC. The thermo-mechanical behaviour under HHF loading has been evaluated and compared to the FEM predictions. The measured temperatures and strains confirm the chosen FEM approach. This allows a component optimisation to achieve a successful series production of the W7-X divertor target elements

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

    Directory of Open Access Journals (Sweden)

    Abbaspour Babaei M

    2016-08-01

    -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. Keywords: c-Kit, cancer, oncogene, cancer therapy

  13. Synthesis and Activity of a New Series of(Z-3-Phenyl-2-benzoylpropenoic Acid Derivatives as Aldose Reductase Inhibitors

    Directory of Open Access Journals (Sweden)

    Shao-Jie Wang

    2007-04-01

    Full Text Available During the course of studies directed towards the discovery of novel aldose reductase inhibitors for the treatment of diabetic complications, we synthesized a series of new (Z-3-phenyl-2-benzoylpropenoic acid derivatives and tested their in vitro inhibitory activities on rat lens aldose reductase. Of these compounds, (Z-3-(3,4-dihydroxyphenyl-2-(4-methylbenzoylpropenoicacid(3k was identified as the most potent inhibitor, with an IC50 of 0.49μM. The theoretical binding mode of 3k was obtained by simulation of its docking into the active site of the human aldose reductase crystal structure.

  14. Targeting Transcriptional Addictions in Small Cell Lung Cancer with a Covalent CDK7 Inhibitor

    DEFF Research Database (Denmark)

    Christensen, Camilla L; Kwiatkowski, Nicholas; Abraham, Brian J

    2014-01-01

    Small cell lung cancer (SCLC) is an aggressive disease with high mortality, and the identification of effective pharmacological strategies to target SCLC biology represents an urgent need. Using a high-throughput cellular screen of a diverse chemical library, we observe that SCLC is sensitive...... to transcription-targeting drugs, in particular to THZ1, a recently identified covalent inhibitor of cyclin-dependent kinase 7. We find that expression of super-enhancer-associated transcription factor genes, including MYC family proto-oncogenes and neuroendocrine lineage-specific factors, is highly vulnerability...

  15. Development of Anti-Virulence Approaches for Candidiasis via a Novel Series of Small-Molecule Inhibitors of Candida albicans Filamentation

    Directory of Open Access Journals (Sweden)

    Jesus A. Romo

    2017-12-01

    Full Text Available Candida albicans remains the main etiologic agent of candidiasis, the most common fungal infection and now the third most frequent infection in U.S. hospitals. The scarcity of antifungal agents and their limited efficacy contribute to the unacceptably high morbidity and mortality rates associated with these infections. The yeast-to-hypha transition represents the main virulence factor associated with the pathogenesis of C. albicans infections. In addition, filamentation is pivotal for robust biofilm development, which represents another major virulence factor for candidiasis and further complicates treatment. Targeting pathogenic mechanisms rather than growth represents an attractive yet clinically unexploited approach in the development of novel antifungal agents. Here, we performed large-scale phenotypic screening assays with 30,000 drug-like small-molecule compounds within ChemBridge’s DIVERSet chemical library in order to identify small-molecule inhibitors of C. albicans filamentation, and our efforts led to the identification of a novel series of bioactive compounds with a common biaryl amide core structure. The leading compound of this series, N-[3-(allyloxy-phenyl]-4-methoxybenzamide, was able to prevent filamentation under all liquid and solid medium conditions tested, suggesting that it impacts a common core component of the cellular machinery that mediates hypha formation under different environmental conditions. In addition to filamentation, this compound also inhibited C. albicans biofilm formation. This leading compound also demonstrated in vivo activity in clinically relevant murine models of invasive and oral candidiasis. Overall, our results indicate that compounds within this series represent promising candidates for the development of novel anti-virulence approaches to combat C. albicans infections.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Anna Cichonska

    2017-08-01

    Full Text Available 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

  18. Anticancer actions of lysosomally targeted inhibitor, LCL521, of acid ceramidase.

    Directory of Open Access Journals (Sweden)

    Aiping Bai

    Full Text Available Acid ceramidase, which catalyzes ceramide hydrolysis to sphingosine and free fatty acid mainly in the lysosome, is being recognized as a potential therapeutic target for cancer. B13 is an effective and selective acid ceramidase inhibitor in vitro, but not as effective in cells due to poor access to the lysosomal compartment. In order to achieve targeting of B13 to the lysosome, we designed lysosomotropic N, N-dimethyl glycine (DMG-conjugated B13 prodrug LCL521 (1,3-di-DMG-B13. Our previous results indicated the efficient delivery of B13 to the lysosome resulted in augmented effects of LCL521 on cellular acid ceramidase as evaluated by effects on substrate/product levels. Our current studies indicate that functionally, this translated into enhanced inhibition of cell proliferation. Moreover, there were greater synergistic effects of LCL521 with either ionizing radiation or Tamoxifen. Taken together, these results clearly indicate that compartmental targeting for the inhibition of acid ceramidase is an efficient and valuable therapeutic strategy.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Guowei ZHANG

    2017-04-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  5. Preferential Selectivity of Inhibitors with Human Tau Protein Kinase Gsk3 Elucidates Their Potential Roles for Off-Target Alzheimer’s Therapy

    Directory of Open Access Journals (Sweden)

    Jagadeesh Kumar Dasappa

    2013-01-01

    Full Text Available Alzheimer’s disease (AD is a neurodegenerative disorder characterized by the accumulation of amyloid beta peptides (A and neurofibrillary tangles (NFTs. The abnormal phosphorylation of tau leads to the formation of NFTs produced by the action of tau kinases, resulting in the loss of neurons and synapse, leading to dementia. Hence, tau kinases have become potential drug target candidates for small molecule inhibitors. With an aim to explore the identification of a common inhibitor, this investigation was undertaken towards analyzing all 10 tau kinases which are implicated in phosphorylation of AD. A set of 7 inhibitors with varied scaffolds were collected from the Protein Data Bank (PDB. The analysis, involving multiple sequence alignment, 3D structural alignment, catalytic active site overlap, and docking studies, has enabled elucidation of the pharmacophoric patterns for the class of 7 inhibitors. Our results divulge that tau protein kinases share a specific set of conserved structural elements for the binding of inhibitors and ATP, respectively. The scaffold of 3-aminopyrrolidine (inhibitor 6 exhibits high preferential affinity with GSK3. Surprisingly, the PDB does not contain the structural details of GSK3 with this specific inhibitor. Thus, our investigations provide vital clues towards design of novel off-target drugs for Alzheimer’s.

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

    Science.gov (United States)

    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

  7. Synthesis and in Vitro and in Vivo Evaluation of Phosphoinositide-3-kinase Inhibitors.

    Science.gov (United States)

    Burger, Matthew T; Knapp, Mark; Wagman, Allan; Ni, Zhi-Jie; Hendrickson, Thomas; Atallah, Gordana; Zhang, Yanchen; Frazier, Kelly; Verhagen, Joelle; Pfister, Keith; Ng, Simon; Smith, Aaron; Bartulis, Sarah; Merrit, Hanne; Weismann, Marion; Xin, Xiaohua; Haznedar, Joshua; Voliva, Charles F; Iwanowicz, Ed; Pecchi, Sabina

    2011-01-13

    Phospoinositide-3-kinases (PI3K) are important oncology targets due to the deregulation of this signaling pathway in a wide variety of human cancers. A series of 2-morpholino, 4-substituted, 6-(3-hydroxyphenyl) pyrimidines have been reported as potent inhibitors of PI3Ks. Herein, we describe the structure-guided optimization of these pyrimidines with a focus on replacing the phenol moiety, while maintaining potent target inhibition and improving in vivo properties. A series of 2-morpholino, 4-substituted, 6-heterocyclic pyrimidines, which potently inhibit PI3K, were discovered. Within this series a compound, 17, was identified with suitable pharmacokinetic (PK) properties, which allowed for the establishment of a PI3K PK/pharmacodynamic-efficacy relationship as determined by in vivo inhibition of AKT(Ser473) phosphorylation and tumor growth inhibition in a mouse A2780 tumor xenograft model.

  8. Targeting TORC1/2 Enhances Sensitivity to EGFR Inhibitors in Head and Neck Cancer Preclinical Models

    Directory of Open Access Journals (Sweden)

    Andre Cassell

    2012-11-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  10. Diverse inhibitor chemotypes targeting Trypanosoma cruzi CYP51.

    Directory of Open Access Journals (Sweden)

    Shamila S Gunatilleke

    Full Text Available Chagas Disease, a WHO- and NIH-designated neglected tropical disease, is endemic in Latin America and an emerging infection in North America and Europe as a result of population moves. Although a major cause of morbidity and mortality due to heart failure, as well as inflicting a heavy economic burden in affected regions, Chagas Disease elicits scant notice from the pharmaceutical industry because of adverse economic incentives. The discovery and development of new routes to chemotherapy for Chagas Disease is a clear priority.The similarity between the membrane sterol requirements of pathogenic fungi and those of the parasitic protozoon Trypanosoma cruzi, the causative agent of Chagas human cardiopathy, has led to repurposing anti-fungal azole inhibitors of sterol 14α-demethylase (CYP51 for the treatment of Chagas Disease. To diversify the therapeutic pipeline of anti-Chagasic drug candidates we exploited an approach that included directly probing the T. cruzi CYP51 active site with a library of synthetic small molecules. Target-based high-throughput screening reduced the library of ∼104,000 small molecules to 185 hits with estimated nanomolar K(D values, while cross-validation against T. cruzi-infected skeletal myoblast cells yielded 57 active hits with EC(50 <10 µM. Two pools of hits partially overlapped. The top hit inhibited T. cruzi with EC(50 of 17 nM and was trypanocidal at 40 nM.The hits are structurally diverse, demonstrating that CYP51 is a rather permissive enzyme target for small molecules. Cheminformatic analysis of the hits suggests that CYP51 pharmacology is similar to that of other cytochromes P450 therapeutic targets, including thromboxane synthase (CYP5, fatty acid ω-hydroxylases (CYP4, 17α-hydroxylase/17,20-lyase (CYP17 and aromatase (CYP19. Surprisingly, strong similarity is suggested to glutaminyl-peptide cyclotransferase, which is unrelated to CYP51 by sequence or structure. Lead compounds developed by pharmaceutical

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

    Science.gov (United States)

    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.

  12. WRN-targeted therapy using inhibitors NSC 19630 and NSC 617145 induce apoptosis in HTLV-1-transformed adult T-cell leukemia cells

    Directory of Open Access Journals (Sweden)

    R. Moles

    2016-11-01

    Full Text Available Abstract Background Human T-cell leukemia virus type 1 (HTLV-1 infection is associated with adult T-cell leukemia/lymphoma (ATLL, a lymphoproliferative malignancy with a dismal prognosis and limited therapeutic options. Recent evidence shows that HTLV-1-transformed cells present defects in both DNA replication and DNA repair, suggesting that these cells might be particularly sensitive to treatment with a small helicase inhibitor. Because the “Werner syndrome ATP-dependent helicase” encoded by the WRN gene plays important roles in both cellular proliferation and DNA repair, we hypothesized that inhibition of WRN activity could be used as a new strategy to target ATLL cells. Methods Our analysis demonstrates an apoptotic effect induced by the WRN helicase inhibitor in HTLV-1-transformed cells in vitro and ATL-derived cell lines. Inhibition of cellular proliferation and induction of apoptosis were demonstrated with cell cycle analysis, XTT proliferation assay, clonogenic assay, annexin V staining, and measurement of mitochondrial transmembrane potential. Results Targeted inhibition of the WRN helicase induced cell cycle arrest and apoptosis in HTLV-1-transformed leukemia cells. Treatment with NSC 19630 (WRN inhibitor induces S-phase cell cycle arrest, disruption of the mitochondrial membrane potential, and decreased expression of anti-apoptotic factor Bcl-2. These events were associated with activation of caspase-3-dependent apoptosis in ATL cells. We identified some ATL cells, ATL-55T and LMY1, less sensitive to NSC 19630 but sensitive to another WRN inhibitor, NSC 617145. Conclusions WRN is essential for survival of ATL cells. Our studies suggest that targeting the WRN helicase with small inhibitors is a novel promising strategy to target HTLV-1-transformed ATL cells.

  13. Antitubercular drugs for an old target: GSK693 as a promising InhA direct inhibitor

    Directory of Open Access Journals (Sweden)

    María Martínez-Hoyos

    2016-06-01

    Full Text Available Despite being one of the first antitubercular agents identified, isoniazid (INH is still the most prescribed drug for prophylaxis and tuberculosis (TB treatment and, together with rifampicin, the pillars of current chemotherapy. A high percentage of isoniazid resistance is linked to mutations in the pro-drug activating enzyme KatG, so the discovery of direct inhibitors (DI of the enoyl-ACP reductase (InhA has been pursued by many groups leading to the identification of different enzyme inhibitors, active against Mycobacterium tuberculosis (Mtb, but with poor physicochemical properties to be considered as preclinical candidates. Here, we present a series of InhA DI active against multidrug (MDR and extensively (XDR drug-resistant clinical isolates as well as in TB murine models when orally dosed that can be a promising foundation for a future treatment.

  14. A targeted enzyme approach to sensitization of tyrosine kinase inhibitor-resistant breast cancer cells.

    Science.gov (United States)

    Giordano, Courtney R; Mueller, Kelly L; Terlecky, Laura J; Krentz, Kendra A; Bollig-Fischer, Aliccia; Terlecky, Stanley R; Boerner, Julie L

    2012-10-01

    Gefitinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) of potential use in patients with breast cancer. Unfortunately, in clinical studies, gefitinib is often ineffective indicating that resistance to EGFR inhibitors may be a common occurrence in cancer of the breast. EGFR has been shown to be overexpressed in breast cancer, and in particular remains hyperphosphorylated in cell lines such as MDA-MB-468 that are resistant to EGFR inhibitors. Here, we investigate the cause of this sustained phosphorylation and the molecular basis for the ineffectiveness of gefitinib. We show that reactive oxygen species (ROS), known to damage cellular macromolecules and to modulate signaling cascades in a variety of human diseases including cancers, appear to play a critical role in mediating EGFR TKI-resistance. Furthermore, elimination of these ROS through use of a cell-penetrating catalase derivative sensitizes the cells to gefitinib. These results suggest a new approach for the treatment of TKI-resistant breast cancer patients specifically, the targeting of ROS and attendant downstream oxidative stress and their effects on signaling cascades. Copyright © 2012. Published by Elsevier Inc.

  15. Mutational analysis of target enzyme recognition of the beta-trefoil fold barley alpha-amylase/subtilisin inhibitor

    DEFF Research Database (Denmark)

    Bønsager, Birgit Christine; Nielsen, Per K.; Abou Hachem, Maher

    2005-01-01

    The barley alpha-amylase/subtilisin inhibitor ( BASI) inhibits alpha-amylase 2 (AMY2) with subnanomolar affinity. The contribution of selected side chains of BASI to this high affinity is discerned in this study, and binding to other targets is investigated. Seven BASI residues along the AMY2-BASI...... interface and four residues in the putative protease-binding loop on the opposite side of the inhibitor were mutated. A total of 15 variants were compared with the wild type by monitoring the alpha-amylase and protease inhibitory activities using Blue Starch and azoalbumin, respectively, and the kinetics...

  16. Identification and development of novel indazole derivatives as potent bacterial peptidoglycan synthesis inhibitors

    Directory of Open Access Journals (Sweden)

    Prasanthi Malapati

    2018-01-01

    Full Text Available Background: Tuberculosis is well-known airborne disease caused by Mycobacterium tuberculosis. Available treatment regimen was unsuccessful in eradicating the deaths caused by the disease worldwide. Owing to the drawbacks such as prolonged treatment period, side effects, and drug tolerance, there resulted in patient noncompliance. In the current study, we attempted to develop inhibitors against unexplored key target glutamate racemase. Methods: Lead identification was done using thermal shift assay from in-house library; inhibitors were developed by lead derivatization technique and evaluated using various biological assays. Results: In indazole series, compounds 11 (6.32 ± 0.35 μM and 22 (6.11 ± 0.51 μM were found to be most promising potent inhibitors among all. These compounds also showed their inhibition on replicating and nonreplicating bacteria. Conclusion: We have developed the novel inhibitors against M. tuberculosis capable of inhibiting active and dormant bacteria, further optimization of inhibitor derivatives can results in better compounds for eradicating tuberculosis.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lasko, Loren M.; Jakob, Clarissa G.; Edalji, Rohinton P.; Qiu, Wei; Montgomery, Debra; Digiammarino, Enrico L.; Hansen, T. Matt; Risi, Roberto M.; Frey, Robin; Manaves, Vlasios; Shaw, Bailin; Algire, Mikkel; Hessler, Paul; Lam, Lloyd T.; Uziel, Tamar; Faivre, Emily; Ferguson, Debra; Buchanan, Fritz G.; Martin, Ruth L.; Torrent, Maricel; Chiang, Gary G.; Karukurichi, Kannan; Langston, J. William; Weinert, Brian T.; Choudhary, Chunaram; de Vries, Peter; Van Drie, John H.; McElligott, David; Kesicki, Ed; Marmorstein, Ronen; Sun, Chaohong; Cole, Philip A.; Rosenberg, Saul H.; Michaelides, Michael R.; Lai, Albert; Bromberg, Kenneth D. (AbbVie); (UCopenhagen); (Petra Pharma); (UPENN); (JHU); (Van Drie); (Faraday)

    2017-09-27

    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, 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.

  18. Development of dihydropyridone indazole amides as selective Rho-kinase inhibitors.

    Science.gov (United States)

    Goodman, Krista B; Cui, Haifeng; Dowdell, Sarah E; Gaitanopoulos, Dimitri E; Ivy, Robert L; Sehon, Clark A; Stavenger, Robert A; Wang, Gren Z; Viet, Andrew Q; Xu, Weiwei; Ye, Guosen; Semus, Simon F; Evans, Christopher; Fries, Harvey E; Jolivette, Larry J; Kirkpatrick, Robert B; Dul, Edward; Khandekar, Sanjay S; Yi, Tracey; Jung, David K; Wright, Lois L; Smith, Gary K; Behm, David J; Bentley, Ross; Doe, Christopher P; Hu, Erding; Lee, Dennis

    2007-01-11

    Rho kinase (ROCK1) mediates vascular smooth muscle contraction and is a potential target for the treatment of hypertension and related disorders. Indazole amide 3 was identified as a potent and selective ROCK1 inhibitor but possessed poor oral bioavailability. Optimization of this lead resulted in the discovery of a series of dihydropyridones, exemplified by 13, with improved pharmacokinetic parameters relative to the initial lead. Indazole substitution played a critical role in decreasing clearance and improving oral bioavailability.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  1. Evolution of a Novel, Orally Bioavailable Series of PI3Kδ Inhibitors from an Inhaled Lead for the Treatment of Respiratory Disease.

    Science.gov (United States)

    Amour, Augustin; Barton, Nick; Cooper, Anthony W J; Inglis, Graham; Jamieson, Craig; Luscombe, Christopher N; Morrell, Josie; Peace, Simon; Perez, David; Rowland, Paul; Tame, Chris; Uddin, Sorif; Vitulli, Giovanni; Wellaway, Natalie

    2016-08-11

    A four-step process of high-quality modeling of existing data, deconstruction, identification of replacement cores, and an innovative synthetic regrowth strategy led to the rapid discovery of a novel oral series of PI3Kδ inhibitors with promising selectivity and excellent in vivo characteristics.

  2. Target Therapy Using a Small Molecule Inhibitor against Angiogenic Receptors in Pancreatic Cancer

    Directory of Open Access Journals (Sweden)

    Peter Büchler

    2007-02-01

    Full Text Available PURPOSE: PD173074, a small molecule inhibitor of VEGF-RII and FGF-RI, targets neoangiogenesis and mitogenesis. This study aimed to analyze a singlecompound-driven inhibition of FGF and VEGF receptors in pancreatic cancer. EXPERIMENTAL DESIGN: RT-PCR and Western blots were performed to quantify protein expression and phosphorylation. Anchorage dependent and independent growth assays were used to study cell growth. With flow cytometry, cell cycle analysis and apoptosis were studied. In vivo HPAF-II and MIA PaCa-2 cells were xenografted. Animals were treated daily for 10 weeks. Immunohistochemistry was used to quantify microvessel density and apoptosis. RESULTS: Highest levels of FGF-RI were detectable in MIA PaCa-2 cells, lowest in HPAF-II cells. PD173074 inhibited cell growth most prominently in cells expressing high levels of FGF-RI. Cell cycle progression was inhibited by blocking transition in the G0/G1 phase, and consequently, apoptosis was increased. In vivo significant inhibition of orthotopic tumor growth was achieved by a combination effect of inhibition of mitogenesis, induction of apoptosis, and reduction of angiogenesis in PD173074-treated animals. CONCLUSIONS: These data highlight VEGF-RII and FGF-RI as therapeutic targets and suggest a potential role for the combined use of tyrosine kinase inhibitors in the management of inoperable pancreatic cancer patients.

  3. In silico design and biological evaluation of a dual specificity kinase inhibitor targeting cell cycle progression and angiogenesis.

    Science.gov (United States)

    Latham, Antony M; Kankanala, Jayakanth; Fearnley, Gareth W; Gage, Matthew C; Kearney, Mark T; Homer-Vanniasinkam, Shervanthi; Wheatcroft, Stephen B; Fishwick, Colin W G; Ponnambalam, Sreenivasan

    2014-01-01

    Protein kinases play a central role in tumor progression, regulating fundamental processes such as angiogenesis, proliferation and metastasis. Such enzymes are an increasingly important class of drug target with small molecule kinase inhibitors being a major focus in drug development. However, balancing drug specificity and efficacy is problematic with off-target effects and toxicity issues. We have utilized a rational in silico-based approach to demonstrate the design and study of a novel compound that acts as a dual inhibitor of vascular endothelial growth factor receptor 2 (VEGFR2) and cyclin-dependent kinase 1 (CDK1). This compound acts by simultaneously inhibiting pro-angiogenic signal transduction and cell cycle progression in primary endothelial cells. JK-31 displays potent in vitro activity against recombinant VEGFR2 and CDK1/cyclin B proteins comparable to previously characterized inhibitors. Dual inhibition of the vascular endothelial growth factor A (VEGF-A)-mediated signaling response and CDK1-mediated mitotic entry elicits anti-angiogenic activity both in an endothelial-fibroblast co-culture model and a murine ex vivo model of angiogenesis. We deduce that JK-31 reduces the growth of both human endothelial cells and human breast cancer cells in vitro. This novel synthetic molecule has broad implications for development of similar multi-kinase inhibitors with anti-angiogenic and anti-cancer properties. In silico design is an attractive and innovative method to aid such drug discovery.

  4. Side Effects of Nitrification Inhibitors on Non Target Microbial Processes in Soils

    Directory of Open Access Journals (Sweden)

    Johannes Carl Gottlieb Ottow

    2011-01-01

    Full Text Available Agricultural chemicals have been used extensively in modern agriculture and toxicological studies suggest a great potential for inducing undesirable effects on non target organisms. A model experiment was conducted in order to determine side effects of three nitrification inhibitors (NIs, 3,4dimethylpyrazolephosphate = DMPP, 4-Chlor-methylpyrazole phosphate = ClMPP and dicyandiamide = DCD on non target microbial processes in soils. Side effects and dose response curve of three NIs were quantified under laboratory conditions using silty clay, loam and a sandy soils. Dehydrogenase, dimethylsulfoxide reductase as well as nitrogenase activity (NA and potential denitrification capacity were measured as common and specific non target microbial processes. The influence of 5-1000 times the base concentration, dose response curves were examined, and no observable effect level = NOEL, as well as effective dose ED10 and ED50 (10% and 50% inhibition were calculated. The NOEL for microbial non target processes were about 30–70 times higher than base concentration in all investigated soils. The potential denitrification capacity revealed to be the most sensitive parameter. ClMPP exhibited the strongest influence on the non target microbial processes in the three soils. The NOEL, ED10 and ED50 values were higher in clay than in loamy or sandy soil. The NIs was the most effective in sandy soils.

  5. Design, synthesis and biological evaluation of uncharged catechol derivatives as selective inhibitors of PTP1B.

    Science.gov (United States)

    Li, Xiang-Qian; Xu, Qi; Luo, Jiao; Wang, Li-Jun; Jiang, Bo; Zhang, Ren-Shuai; Shi, Da-Yong

    2017-08-18

    Protein tyrosine phosphatases 1B (PTP1B) is a promising and validated therapeutic target to effectively treat T2DM and obesity. However, the development of charged PTP1B inhibitors was restricted due to their low cell permeability and poor bioavailability. Based on active natural products, two series of uncharged catechol derivatives were identified as PTP1B inhibitors by targeting a secondary aryl phosphate-binding site as well as the catalytic site. The most potent inhibitor 22 showed an IC 50 of 0.487 μM against PTP1B and strong selectivity (27-fold) over TCPTP. Kinetic studies were also performed that 22 act as a competitive PTP1B inhibitor. The treatment of C2C12 myotubes with 22 markedly increased the phosphorylation levels of IRβ, Akt and IRS1 phosphorylation. The similarity of its action profiling with that produced by insulin suggested its potential as a new non-insulin-dependent drug candidate. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Results of the examinations of the W7-X pre-series target elements

    International Nuclear Information System (INIS)

    Boscary, J.; Boeswirth, B.; Greuner, H.; Missirlian, M.; Schedler, B.; Scheiber, K.; Schlosser, J.; Streibl, B.

    2007-01-01

    The target elements of the WENDELSTEIN 7-X (W7-X) divertor are designed to sustain a stationary heat flux of 10 MW/m 2 and to remove a maximum power of 100 kW. CFC Sepcarb NB31 tiles are bonded to a water-cooled CuCrZr heat sink in two steps: active metal casting (AMC) of an AMC -copper interlayer to CFC tiles, electron beam welding (EBW) or hot isostatic pressing (HIP) of the AMC -NB31 tiles to CuCrZr. The fabrication of the whole amount of CFC NB31 has been completed. The key target of the pre-series phase is the qualification of this bond based on a series of examinations. The introduction of silicon during the AMC process significantly improved the strength of the joint between CFC and AMC -copper. The strength of the bond is preserved after either EBW or HIP processes. High heat flux testing carried out in the ion beam facility GLADIS exhibited a too high percentage of defective tiles. Pre-series activities have been extended to reduce the stress concentration at the interface between tiles and heat sink by optimizing the design

  7. Design, Synthesis and in vitro Biochemical Activity of Novel Amino Acid Sulfonohydrazide Inhibitors of MurC.

    Science.gov (United States)

    Frlan, Rok; Kovač, Andreja; Blanot, Didier; Gobec, Stanislav; Pečar, Slavko; Obreza, Aleš

    2011-06-01

    Mur ligases are essential enzymes involved in the cytoplasmic steps of peptidoglycan synthesis which remain attractive, yet unexploited targets. In order to develop new antibacterial agents, we have designed a series of new MurC and MurD inhibitors bearing amino acid sulfonohydrazide moiety. The L-Leu series of this class displayed the highest enzyme inhibition with IC50 in the concentration range between 100 and 500 µM, with L-Thr, L-Pro and L-Ala derivatives being inactive. The most promising compound of the series also expressed weak antibacterial activity against S. aureus with MIC = 128 µg/mL.

  8. Leveraging the Pre-DFG Residue Thr-406 To Obtain High Kinase Selectivity in an Aminopyrazole-Type PAK1 Inhibitor Series.

    Science.gov (United States)

    Rudolph, Joachim; Aliagas, Ignacio; Crawford, James J; Mathieu, Simon; Lee, Wendy; Chao, Qi; Dong, Ping; Rouge, Lionel; Wang, Weiru; Heise, Christopher; Murray, Lesley J; La, Hank; Liu, Yanzhou; Manning, Gerard; Diederich, François; Hoeflich, Klaus P

    2015-06-11

    To increase kinase selectivity in an aminopyrazole-based PAK1 inhibitor series, analogues were designed to interact with the PAK1 deep-front pocket pre-DFG residue Thr-406, a residue that is hydrophobic in most kinases. This goal was achieved by installing lactam head groups to the aminopyrazole hinge binding moiety. The corresponding analogues represent the most kinase selective ATP-competitive Group I PAK inhibitors described to date. Hydrogen bonding with the Thr-406 side chain was demonstrated by X-ray crystallography, and inhibitory activities, particularly against kinases with hydrophobic pre-DFG residues, were mitigated. Leveraging hydrogen bonding side chain interactions with polar pre-DFG residues is unprecedented, and similar strategies should be applicable to other appropriate kinases.

  9. Ribonucleotide Reductase Inhibitors: A New Look at an Old Target for Radiosensitization

    International Nuclear Information System (INIS)

    Chapman, Tobias R.; Kinsella, Timothy J.

    2012-01-01

    Ribonucleotide reductase (RR), the rate limiting enzyme in the synthesis and repair of DNA, has been studied as a target for inhibition in the treatment of cancer for many years. While some researchers have focused on RR inhibitors as chemotherapeutic agents, particularly in hematologic malignancies, some of the most promising data has been generated in the field of radiosensitization. Early pre-clinical studies demonstrated that the addition of the first of these drugs, hydroxyurea, to ionizing radiation (IR) produced a synergistic effect in vitro, leading to a large number of clinical studies in the 1970–1980s. These studies, mainly in cervical cancer, initially produced a great deal of interest, leading to the incorporation of hydroxyurea in the treatment protocols of many institutions. However, over time, the conclusions from these studies have been called into question and hydroxyurea has been replaced in the standard of care of cervical cancer. Over the last 10 years, a number of well-done pre-clinical studies have greatly advanced our understanding of RR as a target. Those advances include the elucidation of the role of p53R2 and our understanding of the temporal relationship between the delivery of IR and the response of RR. At the same time, new inhibitors with increased potency and improved binding characteristics have been discovered, and pre-clinical and early clinical data look promising. Here we present a comprehensive review of the pre-clinical and clinical data in the field to date and provide some discussion of future areas of research.

  10. Ribonucleotide Reductase Inhibitors: A New Look at an Old Target for Radiosensitization

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Tobias R. [Tufts University School of Medicine, Boston, MA (United States); Kinsella, Timothy J., E-mail: tkinsella@lifespan.org [Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, RI (United States)

    2012-01-04

    Ribonucleotide reductase (RR), the rate limiting enzyme in the synthesis and repair of DNA, has been studied as a target for inhibition in the treatment of cancer for many years. While some researchers have focused on RR inhibitors as chemotherapeutic agents, particularly in hematologic malignancies, some of the most promising data has been generated in the field of radiosensitization. Early pre-clinical studies demonstrated that the addition of the first of these drugs, hydroxyurea, to ionizing radiation (IR) produced a synergistic effect in vitro, leading to a large number of clinical studies in the 1970–1980s. These studies, mainly in cervical cancer, initially produced a great deal of interest, leading to the incorporation of hydroxyurea in the treatment protocols of many institutions. However, over time, the conclusions from these studies have been called into question and hydroxyurea has been replaced in the standard of care of cervical cancer. Over the last 10 years, a number of well-done pre-clinical studies have greatly advanced our understanding of RR as a target. Those advances include the elucidation of the role of p53R2 and our understanding of the temporal relationship between the delivery of IR and the response of RR. At the same time, new inhibitors with increased potency and improved binding characteristics have been discovered, and pre-clinical and early clinical data look promising. Here we present a comprehensive review of the pre-clinical and clinical data in the field to date and provide some discussion of future areas of research.

  11. Targeting tumorigenesis: development and use of mTOR inhibitors in cancer therapy

    Directory of Open Access Journals (Sweden)

    Kay Andrea

    2009-10-01

    Full Text Available Abstract The mammalian target of rapamycin (mTOR is an intracellular serine/threonine protein kinase positioned at a central point in a variety of cellular signaling cascades. The established involvement of mTOR activity in the cellular processes that contribute to the development and progression of cancer has identified mTOR as a major link in tumorigenesis. Consequently, inhibitors of mTOR, including temsirolimus, everolimus, and ridaforolimus (formerly deforolimus have been developed and assessed for their safety and efficacy in patients with cancer. Temsirolimus is an intravenously administered agent approved by the US Food and Drug Administration (FDA and the European Medicines Agency (EMEA for the treatment of advanced renal cell carcinoma (RCC. Everolimus is an oral agent that has recently obtained US FDA and EMEA approval for the treatment of advanced RCC after failure of treatment with sunitinib or sorafenib. Ridaforolimus is not yet approved for any indication. The use of mTOR inhibitors, either alone or in combination with other anticancer agents, has the potential to provide anticancer activity in numerous tumor types. Cancer types in which these agents are under evaluation include neuroendocrine tumors, breast cancer, leukemia, lymphoma, hepatocellular carcinoma, gastric cancer, pancreatic cancer, sarcoma, endometrial cancer, and non-small-cell lung cancer. The results of ongoing clinical trials with mTOR inhibitors, as single agents and in combination regimens, will better define their activity in cancer.

  12. Survivin - an inhibitor of apoptosis and a new therapeutic target in cancer

    International Nuclear Information System (INIS)

    Pizem, J.; Coer, A.

    2003-01-01

    Survivin is a unique member of the inhibitor of apoptosis (IAP) protein family. It inhibits apoptosis by interfering with post-mitochondrial events during apoptosis, thus blocking activation of caspases. The expression of survivin is among the most tumour specific of all human genes. It is overexpressed in most human cancers but is not detected in most normal tissues. Some molecular mechanisms of survivin upregulation in cancer have been elucidated, including loss of the wild-type p53. Tumours that overexpress survivin generally bear a worse prognosis and are associated with resistance to therapy. Its differential expression in cancer versus normal tissues makes survivin detection a useful tool in cancer diagnostics and a promising therapeutic target. Survivin targeting has resulted in increased spontaneous and induced apoptosis and inhibition of tumour growth. Some anticancer drugs currently introduced into clinical practice might well act by inactivating survivin. (author)

  13. Small molecules, inhibitors of DNA-PK, targeting DNA repair and beyond

    Directory of Open Access Journals (Sweden)

    David eDavidson

    2013-01-01

    Full Text Available Many current chemotherapies function by damaging genomic DNA in rapidly dividing cells ultimately leading to cell death. This therapeutic approach differentially targets cancer cells that generally display rapid cell division compared to normal tissue cells. However, although these treatments are initially effective in arresting tumor growth and reducing tumor burden, resistance and disease progression eventually occur. A major mechanism underlying this resistance is increased levels of cellular DNA repair. Most cells have complex mechanisms in place to repair DNA damage that occurs due to environmental exposures or normal metabolic processes. These systems, initially overwhelmed when faced with chemotherapy induced DNA damage, become more efficient under constant selective pressure and as a result chemotherapies become less effective. Thus, inhibiting DNA repair pathways using target specific small molecule inhibitors may overcome cellular resistance to DNA damaging chemotherapies. Non-homologous end joining (NHEJ a major mechanism for the repair of double strand breaks (DSB in DNA is regulated in part by the serine/threonine kinase, DNA dependent protein kinase (DNA-PK. The DNA-PK holoenzyme acts as a scaffold protein tethering broken DNA ends and recruiting other repair molecules. It also has enzymatic activity that may be involved in DNA damage signaling. Because of its’ central role in repair of DSBs, DNA-PK has been the focus of a number of small molecule studies. In these studies specific DNA-PK inhibitors have shown efficacy in synergizing chemotherapies in vitro. However, compounds currently known to specifically inhibit DNA-PK are limited by poor pharmacokinetics: these compounds have poor solubility and have high metabolic lability in vivo leading to short serum half-lives. Future improvement in DNA-PK inhibition will likely be achieved by designing new molecules based on the recently reported crystallographic structure of DNA

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

    Science.gov (United States)

    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.

  15. Cobalt (III) complexes as novel matrix metalloproteinase-9 inhibitors

    International Nuclear Information System (INIS)

    Lee, Jiyoun

    2012-01-01

    We have synthesized a series of novel MMP-9 inhibitors containing cobalt(III) complexes. The synthesized cobalt(III) complexes are effective as enzyme inhibitors and the attachment of a biphenyl group enhanced the efficiency of enzyme inhibition up to 6-fold. When compared to the reported non-hydroxamate MMP inhibitors, the synthesized complexes showed comparable in vitro potency. The enzyme assay showed that the cobalt(III) complex can disrupt the zinc binding active site of MMP-9 and is proposed to work via a ligand exchange mechanism. Since histidine residues are essential for the catalytic activity of a large percentage of enzymes and zinc finger proteins, these cobalt(III) complexes can serve as a prototype inhibitor towards various zinc containing enzymes and proteins. Matrix metalloproteinases (MMPs) are a family of zinc binding endopeptidases that play crucial roles in various physiological processes and diseases such as embryogenic growth, angiogenesis, arthritis, skin ulceration, liver fibrosis and tumor metastasis. Because of their implications in a wide range of diseases, MMPs are considered as intriguing drug targets. The majority of MMP inhibitors are organic small molecules containing a hydroxamate functionality for the zinc binding group. This hydroxamate group binds to a zinc(II) center in a bidentate fashion and creates a distorted trigonal bipyramidal geometry

  16. Cobalt (III) complexes as novel matrix metalloproteinase-9 inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jiyoun [Sungshin Women' s Univ., Seoul (Korea, Republic of)

    2012-04-15

    We have synthesized a series of novel MMP-9 inhibitors containing cobalt(III) complexes. The synthesized cobalt(III) complexes are effective as enzyme inhibitors and the attachment of a biphenyl group enhanced the efficiency of enzyme inhibition up to 6-fold. When compared to the reported non-hydroxamate MMP inhibitors, the synthesized complexes showed comparable in vitro potency. The enzyme assay showed that the cobalt(III) complex can disrupt the zinc binding active site of MMP-9 and is proposed to work via a ligand exchange mechanism. Since histidine residues are essential for the catalytic activity of a large percentage of enzymes and zinc finger proteins, these cobalt(III) complexes can serve as a prototype inhibitor towards various zinc containing enzymes and proteins. Matrix metalloproteinases (MMPs) are a family of zinc binding endopeptidases that play crucial roles in various physiological processes and diseases such as embryogenic growth, angiogenesis, arthritis, skin ulceration, liver fibrosis and tumor metastasis. Because of their implications in a wide range of diseases, MMPs are considered as intriguing drug targets. The majority of MMP inhibitors are organic small molecules containing a hydroxamate functionality for the zinc binding group. This hydroxamate group binds to a zinc(II) center in a bidentate fashion and creates a distorted trigonal bipyramidal geometry.

  17. A new screening method to identify inhibitors of the Lol (localization of lipoproteins) system, a novel antibacterial target.

    Science.gov (United States)

    Ito, Hideaki; Ura, Atsushi; Oyamada, Yoshihiro; Yoshida, Hiroaki; Yamagishi, Jun-Ichi; Narita, Shin-Ichiro; Matsuyama, Shin-Ichi; Tokuda, Hajime

    2007-01-01

    As the Lol system, which is involved in localization of lipoproteins, is essential for Escherichia coli growth and widely conserved among gram-negative bacteria, it is considered to be a promising target for the development of anti-gram-negative bacterial agents. However, no high-throughput screening method has so far been developed to screen for Lol system inhibitors. By combining three assay systems (anucleate cell blue assay, Lpp assay, and LolA-dependent release inhibition assay) and a drug susceptibility test, we have successfully developed a new screening method for identification of compounds that inhibit the Lol system. Using this new screening method, we screened 23,600 in-house chemical compounds and found 2 Lol system inhibitors. We therefore conclude that our new screening method can efficiently identify new antibacterial agents that target the Lol system.

  18. Las series televisivas juveniles: tramas y conflictos en una «teen series» Television Fiction Series Targeted at Young Audience: Plots and Conflicts Portrayed in a Teen Series

    Directory of Open Access Journals (Sweden)

    Núria García Muñoz

    2011-10-01

    Full Text Available Se presentan los principales hallazgos de un estudio sobre las «teen series», es decir las series de ficción televisiva protagonizadas por personajes adolescentes y dirigidas expresamente a una audiencia juvenil. El análisis del retrato de los jóvenes representados en productos específicamente dirigidos a un público juvenil tiene un valor muy significativo tanto por la producción de ficción como por la recepción, ya que los consumidores potenciales se encuentran en un momento clave del proceso de construcción de sus identidades. Después de repasar los principales antecedentes en el estudio de la representación de los jóvenes en la ficción televisiva, se describe el marco conceptual relativo a las «teen series» y se discute su relación con el consumo juvenil. Sucesivamente se presenta un estudio de caso que consiste en un análisis de contenido de la serie norteamericana «Dawson’s creek», realizado sobre una muestra representativa de tres temporadas de la serie, para analizar dos grupos de variables: variables relativas a los personajes y variables relativas a las tramas y a los conflictos. Se discuten los resultados relativos al segundo grupo de variables, con particular atención a las características de las tramas y al papel de los personajes en el desarrollo y en la resolución de las mismas. La aceptación de la identidad personal, el amor y la amistad han resultado ser las temáticas más recurrentes. Además, las relaciones sociales entre los personajes han resultado ejercer un papel fundamental en el desarrollo de las tramas y de los conflictos.This paper presents the main findings of a research project on teen series, which are television fiction series featuring teenagers and specifically targeted at a young audience. The analysis of the portrayal of young people in television fictional series specifically targeted at a young audience has a meaningful value both for television production and for audience reception

  19. Development of a series of aryl pyrimidine kynurenine monooxygenase inhibitors as potential therapeutic agents for the treatment of Huntington's disease.

    Science.gov (United States)

    Toledo-Sherman, Leticia M; Prime, Michael E; Mrzljak, Ladislav; Beconi, Maria G; Beresford, Alan; Brookfield, Frederick A; Brown, Christopher J; Cardaun, Isabell; Courtney, Stephen M; Dijkman, Ulrike; Hamelin-Flegg, Estelle; Johnson, Peter D; Kempf, Valerie; Lyons, Kathy; Matthews, Kimberly; Mitchell, William L; O'Connell, Catherine; Pena, Paula; Powell, Kendall; Rassoulpour, Arash; Reed, Laura; Reindl, Wolfgang; Selvaratnam, Suganathan; Friley, Weslyn Ward; Weddell, Derek A; Went, Naomi E; Wheelan, Patricia; Winkler, Christin; Winkler, Dirk; Wityak, John; Yarnold, Christopher J; Yates, Dawn; Munoz-Sanjuan, Ignacio; Dominguez, Celia

    2015-02-12

    We report on the development of a series of pyrimidine carboxylic acids that are potent and selective inhibitors of kynurenine monooxygenase and competitive for kynurenine. We describe the SAR for this novel series and report on their inhibition of KMO activity in biochemical and cellular assays and their selectivity against other kynurenine pathway enzymes. We describe the optimization process that led to the identification of a program lead compound with a suitable ADME/PK profile for therapeutic development. We demonstrate that systemic inhibition of KMO in vivo with this lead compound provides pharmacodynamic evidence for modulation of kynurenine pathway metabolites both in the periphery and in the central nervous system.

  20. Comparison of responses of human melanoma cell lines to MEK and BRAF inhibitors

    Directory of Open Access Journals (Sweden)

    Clare Judith Stones

    2013-05-01

    Full Text Available The NRAS and BRAF genes are frequently mutated in melanoma, suggesting that the NRAS-BRAF-MEK-ERK signalling pathway is an important target for therapy. Two classes of drugs, one targeting activated BRAF and one targeting MEK, are currently undergoing clinical evaluation. We have analysed the NRAS and BRAF mutational status of a series of 44 early passage lines developed from New Zealand patients with metastatic melanoma. 41% of the lines analysed had BRAF mutations, 23% had NRAS mutations and 36% had neither. We then determined IC50 values (drug concentrations for 50% growth inhibition for CI-1040, a commonly used inhibitor of MEK kinase; trametinib, a clinical agent targeting MEK kinase; and vemurafenib, an inhibitor of mutant BRAF kinase. Cell lines with activating BRAF mutations were significantly more sensitive to vemurafenib than lines with NRAS mutations or lines lacking either mutation (p < 0.001. IC50 values for CI-1040 and trametinib were strongly correlated (r = 0.98 with trametinib showing ~100-fold greater potency. Cell lines sensitive to vemurafenib were also sensitive to CI-1040 and trametinib, but there was no relationship between IC50 values and NRAS mutation status. A small number of lines lacking a BRAF mutation were sensitive to CI-1040 but resistant to vemurafenib. We used western blotting to investigate the effect on ERK phosphorylation of CI-1040 in four lines, of vemurafenib in two lines and of trametinib in two lines. The results support the view that MEK inhibitors might be combined with BRAF inhibitors in the treatment melanomas of with activated BRAF. The high sensitivity to trametinib of some lines with wild-type BRAF status also suggests that MEK inhibitors could have a therapeutic effect against some melanomas as single agents.

  1. Systematic Kinase Inhibitor Profiling Identifies CDK9 as a Synthetic Lethal Target in NUT Midline Carcinoma

    Directory of Open Access Journals (Sweden)

    Johannes Brägelmann

    2017-09-01

    Full Text Available Kinase inhibitors represent the backbone of targeted cancer therapy, yet only a limited number of oncogenic drivers are directly druggable. By interrogating the activity of 1,505 kinase inhibitors, we found that BRD4-NUT-rearranged NUT midline carcinoma (NMC cells are specifically killed by CDK9 inhibition (CDK9i and depend on CDK9 and Cyclin-T1 expression. We show that CDK9i leads to robust induction of apoptosis and of markers of DNA damage response in NMC cells. While both CDK9i and bromodomain inhibition over time result in reduced Myc protein expression, only bromodomain inhibition induces cell differentiation and a p21-induced cell-cycle arrest in these cells. Finally, RNA-seq and ChIP-based analyses reveal a BRD4-NUT-specific CDK9i-induced perturbation of transcriptional elongation. Thus, our data provide a mechanistic basis for the genotype-dependent vulnerability of NMC cells to CDK9i that may be of relevance for the development of targeted therapies for NMC patients.

  2. A potent series targeting the malarial cGMP-dependent protein kinase clears infection and blocks transmission.

    Science.gov (United States)

    Baker, David A; Stewart, Lindsay B; Large, Jonathan M; Bowyer, Paul W; Ansell, Keith H; Jiménez-Díaz, María B; El Bakkouri, Majida; Birchall, Kristian; Dechering, Koen J; Bouloc, Nathalie S; Coombs, Peter J; Whalley, David; Harding, Denise J; Smiljanic-Hurley, Ela; Wheldon, Mary C; Walker, Eloise M; Dessens, Johannes T; Lafuente, María José; Sanz, Laura M; Gamo, Francisco-Javier; Ferrer, Santiago B; Hui, Raymond; Bousema, Teun; Angulo-Barturén, Iñigo; Merritt, Andy T; Croft, Simon L; Gutteridge, Winston E; Kettleborough, Catherine A; Osborne, Simon A

    2017-09-05

    To combat drug resistance, new chemical entities are urgently required for use in next generation anti-malarial combinations. We report here the results of a medicinal chemistry programme focused on an imidazopyridine series targeting the Plasmodium falciparum cyclic GMP-dependent protein kinase (PfPKG). The most potent compound (ML10) has an IC 50 of 160 pM in a PfPKG kinase assay and inhibits P. falciparum blood stage proliferation in vitro with an EC 50 of 2.1 nM. Oral dosing renders blood stage parasitaemia undetectable in vivo using a P. falciparum SCID mouse model. The series targets both merozoite egress and erythrocyte invasion, but crucially, also blocks transmission of mature P. falciparum gametocytes to Anopheles stephensi mosquitoes. A co-crystal structure of PvPKG bound to ML10, reveals intimate molecular contacts that explain the high levels of potency and selectivity we have measured. The properties of this series warrant consideration for further development to produce an antimalarial drug.Protein kinases are promising drug targets for treatment of malaria. Here, starting with a medicinal chemistry approach, Baker et al. generate an imidazopyridine that selectively targets Plasmodium falciparum PKG, inhibits blood stage parasite growth in vitro and in mice and blocks transmission to mosquitoes.

  3. Theoretical study on the interaction of pyrrolopyrimidine derivatives as LIMK2 inhibitors: insight into structure-based inhibitor design.

    Science.gov (United States)

    Shen, Mingyun; Zhou, Shunye; Li, Youyong; Li, Dan; Hou, Tingjun

    2013-10-01

    LIM kinases (LIMKs), downstream of Rho-associated protein kinases (ROCKs) and p21-activated protein kinases (PAKs), are shown to be promising targets for the treatment of cancers. In this study, the inhibition mechanism of 41 pyrrolopyrimidine derivatives as LIMK2 inhibitors was explored through a series of theoretical approaches. First, a model of LIMK2 was generated through molecular homology modeling, and the studied inhibitors were docked into the binding active site of LIMK2 by the docking protocol, taking into consideration the flexibility of the protein. The binding poses predicted by molecular docking for 17 selected inhibitors with different bioactivities complexed with LIMK2 underwent molecular dynamics (MD) simulations, and the binding free energies for the complexes were predicted by using the molecular mechanics/generalized born surface area (MM/GBSA) method. The predicted binding free energies correlated well with the experimental bioactivities (r(2) = 0.63 or 0.62). Next, the free energy decomposition analysis was utilized to highlight the following key structural features related to biological activity: (1) the important H-bond between Ile408 and pyrrolopyrimidine, (2) the H-bonds between the inhibitors and Asp469 and Gly471 which maintain the stability of the DFG-out conformation, and (3) the hydrophobic interactions between the inhibitors and several key residues (Leu337, Phe342, Ala345, Val358, Lys360, Leu389, Ile408, Leu458 and Leu472). Finally, a variety of LIMK2 inhibitors with a pyrrolopyrimidine scaffold were designed, some of which showed improved potency according to the predictions. Our studies suggest that the use of molecular docking with MD simulations and free energy calculations could be a powerful tool for understanding the binding mechanism of LIMK2 inhibitors and for the design of more potent LIMK2 inhibitors.

  4. In silico design and biological evaluation of a dual specificity kinase inhibitor targeting cell cycle progression and angiogenesis.

    Directory of Open Access Journals (Sweden)

    Antony M Latham

    Full Text Available Protein kinases play a central role in tumor progression, regulating fundamental processes such as angiogenesis, proliferation and metastasis. Such enzymes are an increasingly important class of drug target with small molecule kinase inhibitors being a major focus in drug development. However, balancing drug specificity and efficacy is problematic with off-target effects and toxicity issues.We have utilized a rational in silico-based approach to demonstrate the design and study of a novel compound that acts as a dual inhibitor of vascular endothelial growth factor receptor 2 (VEGFR2 and cyclin-dependent kinase 1 (CDK1. This compound acts by simultaneously inhibiting pro-angiogenic signal transduction and cell cycle progression in primary endothelial cells. JK-31 displays potent in vitro activity against recombinant VEGFR2 and CDK1/cyclin B proteins comparable to previously characterized inhibitors. Dual inhibition of the vascular endothelial growth factor A (VEGF-A-mediated signaling response and CDK1-mediated mitotic entry elicits anti-angiogenic activity both in an endothelial-fibroblast co-culture model and a murine ex vivo model of angiogenesis.We deduce that JK-31 reduces the growth of both human endothelial cells and human breast cancer cells in vitro. This novel synthetic molecule has broad implications for development of similar multi-kinase inhibitors with anti-angiogenic and anti-cancer properties. In silico design is an attractive and innovative method to aid such drug discovery.

  5. HER2-targeted therapy in breast cancer. Monoclonal antibodies and tyrosine kinase inhibitors

    DEFF Research Database (Denmark)

    Nielsen, Dorte Lisbet; Andersson, Michael; Kamby, Claus

    2008-01-01

    There is strong clinical evidence that trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor (HER) two tyrosine kinase receptor, is an important component of first-line treatment of patients with HER2-positive metastatic breast cancer. In particular the combination...... of trastuzumab to chemotherapy improves disease-free and overall survival. The use of lapatinib, a dual tyrosine kinase inhibitor of both HER1 and HER2, in combination with capecitabine in the second-line treatment of HER2-positive patients with metastatic breast cancer previously treated with trastuzumab has...

  6. Dihydroquinazolines as a novel class of Trypanosoma brucei trypanothione reductase inhibitors: discovery, synthesis, and characterization of their binding mode by protein crystallography.

    Science.gov (United States)

    Patterson, Stephen; Alphey, Magnus S; Jones, Deuan C; Shanks, Emma J; Street, Ian P; Frearson, Julie A; Wyatt, Paul G; Gilbert, Ian H; Fairlamb, Alan H

    2011-10-13

    Trypanothione reductase (TryR) is a genetically validated drug target in the parasite Trypanosoma brucei , the causative agent of human African trypanosomiasis. Here we report the discovery, synthesis, and development of a novel series of TryR inhibitors based on a 3,4-dihydroquinazoline scaffold. In addition, a high resolution crystal structure of TryR, alone and in complex with substrates and inhibitors from this series, is presented. This represents the first report of a high resolution complex between a noncovalent ligand and this enzyme. Structural studies revealed that upon ligand binding the enzyme undergoes a conformational change to create a new subpocket which is occupied by an aryl group on the ligand. Therefore, the inhibitor, in effect, creates its own small binding pocket within the otherwise large, solvent exposed active site. The TryR-ligand structure was subsequently used to guide the synthesis of inhibitors, including analogues that challenged the induced subpocket. This resulted in the development of inhibitors with improved potency against both TryR and T. brucei parasites in a whole cell assay.

  7. Systematic Analysis of Time-Series Gene Expression Data on Tumor Cell-Selective Apoptotic Responses to HDAC Inhibitors

    Directory of Open Access Journals (Sweden)

    Yun-feng Qi

    2014-01-01

    Full Text Available SAHA (suberoylanilide hydroxamic acid or vorinostat is the first nonselective histone deacetylase (HDAC inhibitor approved by the US Food and Drug Administration (FDA. SAHA affects histone acetylation in chromatin and a variety of nonhistone substrates, thus influencing many cellular processes. In particularly, SAHA induces selective apoptosis of tumor cells, although the mechanism is not well understood. A series of microarray experiments was recently conducted to investigate tumor cell-selective proapoptotic transcriptional responses induced by SAHA. Based on that gene expression time series, we propose a novel framework for detailed analysis of the mechanism of tumor cell apoptosis selectively induced by SAHA. Our analyses indicated that SAHA selectively disrupted the DNA damage response, cell cycle, p53 expression, and mitochondrial integrity of tumor samples to induce selective tumor cell apoptosis. Our results suggest a possible regulation network. Our research extends the existing research.

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

    Directory of Open Access Journals (Sweden)

    Sehgal SA

    2015-07-01

    Full Text Available Sheikh Arslan Sehgal,1,2 Shazia Mannan,2,* Sumaira Kanwal,2,* Ishrat Naveed,1 Asif Mir1 1Department of Bioinformatics and Biotechnology, International Islamic University, Islamabad, Pakistan; 2Department of Biosciences, COMSATS Institute of Information Technology, Sahiwal, Pakistan *These authors contributed equally to this work Abstract: 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. Keywords: schizophrenia, bioinformatics, modeling, docking, DAOA, G72, DAO, computer-aided drug designing, phylogenetic analysis, d-amino acid oxidase

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

    Science.gov (United States)

    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

  10. Hands-On Approach to Structure Activity Relationships: The Synthesis, Testing, and Hansch Analysis of a Series of Acetylcholineesterase Inhibitors

    Science.gov (United States)

    Locock, Katherine; Tran, Hue; Codd, Rachel; Allan, Robin

    2015-01-01

    This series of three practical sessions centers on drugs that inhibit the enzyme acetylcholineesterase. This enzyme is responsible for the inactivation of acetylcholine and has been the target of drugs to treat glaucoma and Alzheimer's disease and for a number of insecticides and warfare agents. These sessions relate to a series of carbamate…

  11. BET Bromodomain Inhibitors with One-Step Synthesis Discovered from Virtual Screen.

    Science.gov (United States)

    Ayoub, Alex M; Hawk, Laura M L; Herzig, Ryan J; Jiang, Jiewei; Wisniewski, Andrea J; Gee, Clifford T; Zhao, Peiliang; Zhu, Jin-Yi; Berndt, Norbert; Offei-Addo, Nana K; Scott, Thomas G; Qi, Jun; Bradner, James E; Ward, Timothy R; Schönbrunn, Ernst; Georg, Gunda I; Pomerantz, William C K

    2017-06-22

    Chemical inhibition of epigenetic regulatory proteins BrdT and Brd4 is emerging as a promising therapeutic strategy in contraception, cancer, and heart disease. We report an easily synthesized dihydropyridopyrimidine pan-BET inhibitor scaffold, which was uncovered via a virtual screen followed by testing in a fluorescence anisotropy assay. Dihydropyridopyimidine 3 was subjected to further characterization and is highly selective for the BET family of bromodomains. Structure-activity relationship data and ligand deconstruction highlight the importance of the substitution of the uracil moiety for potency and selectivity. Compound 3 was also cocrystallized with Brd4 for determining the ligand binding pose and rationalizing subsequent structure-activity data. An additional series of dihydropyridopyrimidines was synthesized to exploit the proximity of a channel near the ZA loop of Brd4, leading to compounds with submicromolar affinity and cellular target engagement. Given these findings, novel and easily synthesized inhibitors are being introduced to the growing field of bromodomain inhibitor development.

  12. BET Bromodomain Inhibitors with One-Step Synthesis Discovered from Virtual Screen

    Energy Technology Data Exchange (ETDEWEB)

    Ayoub, Alex M.; Hawk, Laura M.L.; Herzig, Ryan J.; Jiang, Jiewei; Wisniewski, Andrea J.; Gee, Clifford T.; Zhao, Peiliang; Zhu, Jin-Yi; Berndt, Norbert; Offei-Addo, Nana K.; Scott, Thomas G.; Qi, Jun; Bradner, James E.; Ward, Timothy R.; Schönbrunn, Ernst; Georg, Gunda I.; Pomerantz, William C.K. (Moffitt); (UMM); (Harvard-Med)

    2017-06-06

    Chemical inhibition of epigenetic regulatory proteins BrdT and Brd4 is emerging as a promising therapeutic strategy in contraception, cancer, and heart disease. We report an easily synthesized dihydropyridopyrimidine pan-BET inhibitor scaffold, which was uncovered via a virtual screen followed by testing in a fluorescence anisotropy assay. Dihydropyridopyimidine 3 was subjected to further characterization and is highly selective for the BET family of bromodomains. Structure–activity relationship data and ligand deconstruction highlight the importance of the substitution of the uracil moiety for potency and selectivity. Compound 3 was also cocrystallized with Brd4 for determining the ligand binding pose and rationalizing subsequent structure–activity data. An additional series of dihydropyridopyrimidines was synthesized to exploit the proximity of a channel near the ZA loop of Brd4, leading to compounds with submicromolar affinity and cellular target engagement. Given these findings, novel and easily synthesized inhibitors are being introduced to the growing field of bromodomain inhibitor development.

  13. Selective Inhibitors of Protozoan Protein N-myristoyltransferases as Starting Points for Tropical Disease Medicinal Chemistry Programs

    Science.gov (United States)

    Bell, Andrew S.; Mills, James E.; Williams, Gareth P.; Brannigan, James A.; Wilkinson, Anthony J.; Parkinson, Tanya; Leatherbarrow, Robin J.; Tate, Edward W.; Holder, Anthony A.; Smith, Deborah F.

    2012-01-01

    Inhibition of N-myristoyltransferase has been validated pre-clinically as a target for the treatment of fungal and trypanosome infections, using species-specific inhibitors. In order to identify inhibitors of protozoan NMTs, we chose to screen a diverse subset of the Pfizer corporate collection against Plasmodium falciparum and Leishmania donovani NMTs. Primary screening hits against either enzyme were tested for selectivity over both human NMT isoforms (Hs1 and Hs2) and for broad-spectrum anti-protozoan activity against the NMT from Trypanosoma brucei. Analysis of the screening results has shown that structure-activity relationships (SAR) for Leishmania NMT are divergent from all other NMTs tested, a finding not predicted by sequence similarity calculations, resulting in the identification of four novel series of Leishmania-selective NMT inhibitors. We found a strong overlap between the SARs for Plasmodium NMT and both human NMTs, suggesting that achieving an appropriate selectivity profile will be more challenging. However, we did discover two novel series with selectivity for Plasmodium NMT over the other NMT orthologues in this study, and an additional two structurally distinct series with selectivity over Leishmania NMT. We believe that release of results from this study into the public domain will accelerate the discovery of NMT inhibitors to treat malaria and leishmaniasis. Our screening initiative is another example of how a tripartite partnership involving pharmaceutical industries, academic institutions and governmental/non-governmental organisations such as Medical Research Council and Wellcome Trust can stimulate research for neglected diseases. PMID:22545171

  14. Allosteric small-molecule kinase inhibitors

    DEFF Research Database (Denmark)

    Wu, Peng; Clausen, Mads Hartvig; Nielsen, Thomas E.

    2015-01-01

    current barriers of kinase inhibitors, including poor selectivity and emergence of drug resistance. In spite of the small number of identified allosteric inhibitors in comparison with that of inhibitors targeting the ATP pocket, encouraging results, such as the FDA-approval of the first small...

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

    Science.gov (United States)

    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

  16. Carboxamide Spleen Tyrosine Kinase (Syk) Inhibitors: Leveraging Ground State Interactions To Accelerate Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, J. Michael; Altman, Michael D.; Cash, Brandon; Haidle, Andrew M.; Kubiak, Rachel L.; Maddess, Matthew L.; Yan, Youwei; Northrup, Alan B. (Merck)

    2016-12-08

    Optimization of a series of highly potent and kinome selective carbon-linked carboxamide spleen tyrosine kinase (Syk) inhibitors with favorable drug-like properties is described. A pervasive Ames liability in an analogous nitrogen-linked carboxamide series was obviated by replacement with a carbon-linked moiety. Initial efforts lacked on-target potency, likely due to strain induced between the hinge binding amide and solvent front heterocycle. Consideration of ground state and bound state energetics allowed rapid realization of improved solvent front substituents affording subnanomolar Syk potency and high kinome selectivity. These molecules were also devoid of mutagenicity risk as assessed via the Ames test using the TA97a Salmonella strain.

  17. Immune Checkpoint Inhibitor-Associated Type 1 Diabetes Mellitus: Case Series, Review of the Literature, and Optimal Management

    OpenAIRE

    Kapke, Jonathan; Shaheen, Zachary; Kilari, Deepak; Knudson, Paul; Wong, Stuart

    2017-01-01

    With the introduction of immune checkpoint inhibitors into clinical practice, various autoimmune toxicities have been described. Antibodies targeting the receptor:ligand pairing of programmed death receptor-1 (PD-1) and its cognate ligand programmed death-ligand 1 (PD-L1) in rare reports have been associated with autoimmune diabetes mellitus. We report 2 cases of rapid-onset, insulin-dependent, type 1 diabetes mellitus in the setting of administration of nivolumab, a fully human monoclonal an...

  18. Retro-binding thrombin active site inhibitors: identification of an orally active inhibitor of thrombin catalytic activity.

    Science.gov (United States)

    Iwanowicz, Edwin J; Kimball, S David; Lin, James; Lau, Wan; Han, W-C; Wang, Tammy C; Roberts, Daniel G M; Schumacher, W A; Ogletree, Martin L; Seiler, Steven M

    2002-11-04

    A series of retro-binding inhibitors of human alpha-thrombin was prepared to elucidate structure-activity relationships (SAR) and optimize in vivo performance. Compounds 9 and 11, orally active inhibitors of thrombin catalytic activity, were identified to be efficacious in a thrombin-induced lethality model in mice.

  19. Dengue Virus NS2B/NS3 Protease Inhibitors Exploiting the Prime Side.

    Science.gov (United States)

    Lin, Kuan-Hung; Ali, Akbar; Rusere, Linah; Soumana, Djade I; Kurt Yilmaz, Nese; Schiffer, Celia A

    2017-05-15

    The mosquito-transmitted dengue virus (DENV) infects millions of people in tropical and subtropical regions. Maturation of DENV particles requires proper cleavage of the viral polyprotein, including processing of 8 of the 13 substrate cleavage sites by dengue virus NS2B/NS3 protease. With no available direct-acting antiviral targeting DENV, NS2/NS3 protease is a promising target for inhibitor design. Current design efforts focus on the nonprime side of the DENV protease active site, resulting in highly hydrophilic and nonspecific scaffolds. However, the prime side also significantly modulates DENV protease binding affinity, as revealed by engineering the binding loop of aprotinin, a small protein with high affinity for DENV protease. In this study, we designed a series of cyclic peptides interacting with both sides of the active site as inhibitors of dengue virus protease. The design was based on two aprotinin loops and aimed to leverage both key specific interactions of substrate sequences and the entropic advantage driving aprotinin's high affinity. By optimizing the cyclization linker, length, and amino acid sequence, the tightest cyclic peptide achieved a K i value of 2.9 μM against DENV3 wild-type (WT) protease. These inhibitors provide proof of concept that both sides of DENV protease active site can be exploited to potentially achieve specificity and lower hydrophilicity in the design of inhibitors targeting DENV. IMPORTANCE Viruses of the flaviviral family, including DENV and Zika virus transmitted by Aedes aegypti , continue to be a threat to global health by causing major outbreaks in tropical and subtropical regions, with no available direct-acting antivirals for treatment. A better understanding of the molecular requirements for the design of potent and specific inhibitors against flaviviral proteins will contribute to the development of targeted therapies for infections by these viruses. The cyclic peptides reported here as DENV protease inhibitors

  20. Novel targeted therapeutics: inhibitors of MDM2, ALK and PARP

    Directory of Open Access Journals (Sweden)

    Hsueh Chung-Tsen

    2011-04-01

    Full Text Available Abstract We reviewed preclinical data and clinical development of MDM2 (murine double minute 2, ALK (anaplastic lymphoma kinase and PARP (poly [ADP-ribose] polymerase inhibitors. MDM2 binds to p53, and promotes degradation of p53 through ubiquitin-proteasome degradation. JNJ-26854165 and RO5045337 are 2 small-molecule inhibitors of MDM2 in clinical development. ALK is a transmembrane protein and a member of the insulin receptor tyrosine kinases. EML4-ALK fusion gene is identified in approximately 3-13% of non-small cell lung cancer (NSCLC. Early-phase clinical studies with Crizotinib, an ALK inhibitor, in NSCLC harboring EML4-ALK have demonstrated promising activity with high response rate and prolonged progression-free survival. PARPs are a family of nuclear enzymes that regulates the repair of DNA single-strand breaks through the base excision repair pathway. Randomized phase II study has shown adding PARP-1 inhibitor BSI-201 to cytotoxic chemotherapy improves clinical outcome in patients with triple-negative breast cancer. Olaparib, another oral small-molecule PARP inhibitor, demonstrated encouraging single-agent activity in patients with advanced breast or ovarian cancer. There are 5 other PARP inhibitors currently under active clinical investigation.

  1. Neratinib, A Novel HER2-Targeted Tyrosine Kinase Inhibitor.

    Science.gov (United States)

    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.

  2. Identification of selective inhibitors of RET and comparison with current clinical candidates through development and validation of a robust screening cascade [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Amanda J. Watson

    2016-05-01

    Full Text Available RET (REarranged during Transfection is a receptor tyrosine kinase, which plays pivotal roles in regulating cell survival, differentiation, proliferation, migration and chemotaxis. Activation of RET is a mechanism of oncogenesis in medullary thyroid carcinomas where both germline and sporadic activating somatic mutations are prevalent.   At present, there are no known specific RET inhibitors in clinical development, although many potent inhibitors of RET have been opportunistically identified through selectivity profiling of compounds initially designed to target other tyrosine kinases. Vandetanib and cabozantinib, both multi-kinase inhibitors with RET activity, are approved for use in medullary thyroid carcinoma, but additional pharmacological activities, most notably inhibition of vascular endothelial growth factor - VEGFR2 (KDR, lead to dose-limiting toxicity. The recent identification of RET fusions present in ~1% of lung adenocarcinoma patients has renewed interest in the identification and development of more selective RET inhibitors lacking the toxicities associated with the current treatments.   In an earlier publication [Newton et al, 2016; 1] we reported the discovery of a series of 2-substituted phenol quinazolines as potent and selective RET kinase inhibitors. Here we describe the development of the robust screening cascade which allowed the identification and advancement of this chemical series.  Furthermore we have profiled a panel of RET-active clinical compounds both to validate the cascade and to confirm that none display a RET-selective target profile.

  3. Discovery of a Novel Inhibitor of the Hedgehog Signaling Pathway through Cell-based Compound Discovery and Target Prediction.

    Science.gov (United States)

    Kremer, Lea; Schultz-Fademrecht, Carsten; Baumann, Matthias; Habenberger, Peter; Choidas, Axel; Klebl, Bert; Kordes, Susanne; Schöler, Hans R; Sterneckert, Jared; Ziegler, Slava; Schneider, Gisbert; Waldmann, Herbert

    2017-10-09

    Cell-based assays enable monitoring of small-molecule bioactivity in a target-agnostic manner and help uncover new biological mechanisms. Subsequent identification and validation of the small-molecule targets, typically employing proteomics techniques, is very challenging and limited, in particular if the targets are membrane proteins. Herein, we demonstrate that the combination of cell-based bioactive-compound discovery with cheminformatic target prediction may provide an efficient approach to accelerate the process and render target identification and validation more efficient. Using a cell-based assay, we identified the pyrazolo-imidazole smoothib as a new inhibitor of hedgehog (Hh) signaling and an antagonist of the protein smoothened (SMO) with a novel chemotype. Smoothib targets the heptahelical bundle of SMO, prevents its ciliary localization, reduces the expression of Hh target genes, and suppresses the growth of Ptch +/- medulloblastoma cells. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Proteinaceous alpha-araylase inhibitors

    DEFF Research Database (Denmark)

    Svensson, Birte; Fukuda, Kenji; Nielsen, P.K.

    2004-01-01

    -amylase inhibitors belong to seven different protein structural families, most of which also contain evolutionary related proteins without inhibitory activity. Two families include bifunctional inhibitors acting both on alpha-amylases and proteases. High-resolution structures are available of target alpha...

  5. New halogenated phenylcoumarins as tyrosinase inhibitors.

    Science.gov (United States)

    Matos, Maria João; Santana, Lourdes; Uriarte, Eugenio; Delogu, Giovanna; Corda, Marcella; Fadda, Maria Benedetta; Era, Benedetta; Fais, Antonella

    2011-06-01

    With the aim to find out structural features for the tyrosinase inhibitory activity, in the present communication we report the synthesis and pharmacological evaluation of a new series of phenylcoumarin derivatives with different number of hydroxyl or ether groups and bromo substituent in the scaffold. The synthesized compounds 5-12 were evaluated as mushroom tyrosinase inhibitors showing, two of them, lower IC(50) than the umbelliferone. Compound 12 (IC(50)=215 μM) is the best tyrosinase inhibitor of this series. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Tumor-targeted Nanobullets: Anti-EGFR nanobody-liposomes loaded with anti-IGF-1R kinase inhibitor for cancer treatment.

    Science.gov (United States)

    van der Meel, Roy; Oliveira, Sabrina; Altintas, Isil; Haselberg, Rob; van der Veeken, Joris; Roovers, Rob C; van Bergen en Henegouwen, Paul M P; Storm, Gert; Hennink, Wim E; Schiffelers, Raymond M; Kok, Robbert J

    2012-04-30

    The epidermal growth factor receptor (EGFR) is a validated target for anti-cancer therapy and several EGFR inhibitors are used in the clinic. Over the years, an increasing number of studies have reported on the crosstalk between EGFR and other receptors that can contribute to accelerated cancer development or even acquisition of resistance to anti-EGFR therapies. Combined targeting of EGFR and insulin-like growth factor 1 receptor (IGF-1R) is a rational strategy to potentiate anti-cancer treatment and possibly retard resistance development. In the present study, we have pursued this by encapsulating the kinase inhibitor AG538 in anti-EGFR nanobody-liposomes. The thus developed dual-active nanobody-liposomes associated with EGFR-(over)expressing cells in an EGFR-specific manner and blocked both EGFR and IGF-1R activation, due to the presence of the EGFR-blocking nanobody EGa1 and the anti-IGF-1R kinase inhibitor AG538 respectively. AG538-loaded nanobody-liposomes induced a strong inhibition of tumor cell proliferation even upon short-term exposure followed by a drug-free wash-out period. Therefore, AG538-loaded nanobody-liposomes are a promising anti-cancer formulation due to efficient intracellular delivery of AG538 in combination with antagonistic and downregulating properties of the EGa1 nanobody-liposomes. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Discovery and optimization of potent and selective imidazopyridine and imidazopyridazine mTOR inhibitors.

    Science.gov (United States)

    Peterson, Emily A; Boezio, Alessandro A; Andrews, Paul S; Boezio, Christiane M; Bush, Tammy L; Cheng, Alan C; Choquette, Deborah; Coats, James R; Colletti, Adria E; Copeland, Katrina W; DuPont, Michelle; Graceffa, Russell; Grubinska, Barbara; Kim, Joseph L; Lewis, Richard T; Liu, Jingzhou; Mullady, Erin L; Potashman, Michele H; Romero, Karina; Shaffer, Paul L; Stanton, Mary K; Stellwagen, John C; Teffera, Yohannes; Yi, Shuyan; Cai, Ti; La, Daniel S

    2012-08-01

    mTOR is a critical regulator of cellular signaling downstream of multiple growth factors. The mTOR/PI3K/AKT pathway is frequently mutated in human cancers and is thus an important oncology target. Herein we report the evolution of our program to discover ATP-competitive mTOR inhibitors that demonstrate improved pharmacokinetic properties and selectivity compared to our previous leads. Through targeted SAR and structure-guided design, new imidazopyridine and imidazopyridazine scaffolds were identified that demonstrated superior inhibition of mTOR in cellular assays, selectivity over the closely related PIKK family and improved in vivo clearance over our previously reported benzimidazole series. Copyright © 2012. Published by Elsevier Ltd.

  8. Allosteric inhibition enhances the efficacy of ABL kinase inhibitors to target unmutated BCR-ABL and BCR-ABL-T315I

    Directory of Open Access Journals (Sweden)

    Mian Afsar

    2012-09-01

    Full Text Available Abstract Background Chronic myelogenous leukemia (CML and Philadelphia chromosome-positive (Ph+ acute lymphatic leukemia (Ph + ALL are caused by the t(9;22, which fuses BCR to ABL resulting in deregulated ABL-tyrosine kinase activity. The constitutively activated BCR/ABL-kinase “escapes” the auto-inhibition mechanisms of c-ABL, such as allosteric inhibition. The ABL-kinase inhibitors (AKIs Imatinib, Nilotinib or Dasatinib, which target the ATP-binding site, are effective in Ph + leukemia. Another molecular therapy approach targeting BCR/ABL restores allosteric inhibition. Given the fact that all AKIs fail to inhibit BCR/ABL harboring the ‘gatekeeper’ mutation T315I, we investigated the effects of AKIs in combination with the allosteric inhibitor GNF2 in Ph + leukemia. Methods The efficacy of this approach on the leukemogenic potential of BCR/ABL was studied in Ba/F3 cells, primary murine bone marrow cells, and untransformed Rat-1 fibroblasts expressing BCR/ABL or BCR/ABL-T315I as well as in patient-derived long-term cultures (PDLTC from Ph + ALL-patients. Results Here, we show that GNF-2 increased the effects of AKIs on unmutated BCR/ABL. Interestingly, the combination of Dasatinib and GNF-2 overcame resistance of BCR/ABL-T315I in all models used in a synergistic manner. Conclusions Our observations establish a new approach for the molecular targeting of BCR/ABL and its resistant mutants using a combination of AKIs and allosteric inhibitors.

  9. Targeting GRP75 improves HSP90 inhibitor efficacy by enhancing p53-mediated apoptosis in hepatocellular carcinoma.

    Directory of Open Access Journals (Sweden)

    Weiwei Guo

    Full Text Available Heat shock protein 90 (HSP90 inhibitors are potential drugs for cancer therapy. The inhibition of HSP90 on cancer cell growth largely through degrading client proteins, like Akt and p53, therefore, triggering cancer cell apoptosis. Here, we show that the HSP90 inhibitor 17-AAG can induce the expression of GRP75, a member of heat shock protein 70 (HSP70 family, which, in turn, attenuates the anti-growth effect of HSP90 inhibition on cancer cells. Additionally, 17-AAG enhanced binding of GRP75 and p53, resulting in the retention of p53 in the cytoplasm. Blocking GRP75 with its inhibitor MKT-077 potentiated the anti-tumor effects of 17-AAG by disrupting the formation of GRP75-p53 complexes, thereby facilitating translocation of p53 into the nuclei and leading to the induction of apoptosis-related genes. Finally, dual inhibition of HSP90 and GRP75 was found to significantly inhibit tumor growth in a liver cancer xenograft model. In conclusion, the GRP75 inhibitor MKT-077 enhances 17-AAG-induced apoptosis in HCCs and increases p53-mediated inhibition of tumor growth in vivo. Dual targeting of GRP75 and HSP90 may be a useful strategy for the treatment of HCCs.

  10. Discovery of HDAC inhibitors with potent activity against multiple malaria parasite life cycle stages.

    Science.gov (United States)

    Hansen, Finn K; Sumanadasa, Subathdrage D M; Stenzel, Katharina; Duffy, Sandra; Meister, Stephan; Marek, Linda; Schmetter, Rebekka; Kuna, Krystina; Hamacher, Alexandra; Mordmüller, Benjamin; Kassack, Matthias U; Winzeler, Elizabeth A; Avery, Vicky M; Andrews, Katherine T; Kurz, Thomas

    2014-07-23

    In this work we investigated the antiplasmodial activity of a series of HDAC inhibitors containing an alkoxyamide connecting-unit linker region. HDAC inhibitor 1a (LMK235), previously shown to be a novel and specific inhibitor of human HDAC4 and 5, was used as a starting point to rapidly construct a mini-library of HDAC inhibitors using a straightforward solid-phase supported synthesis. Several of these novel HDAC inhibitors were found to have potent in vitro activity against asexual stage Plasmodium falciparum malaria parasites. Representative compounds were shown to hyperacetylate P. falciparum histones and to inhibit deacetylase activity of recombinant PfHDAC1 and P. falciparum nuclear extracts. All compounds were also screened in vitro for activity against Plasmodium berghei exo-erythrocytic stages and selected compounds were further tested against late stage (IV and V) P. falciparum gametocytes. Of note, some compounds showed nanomolar activity against all three life cycle stages tested (asexual, exo-erythrocytic and gametocyte stages) and several compounds displayed significantly increased parasite selectivity compared to the reference HDAC inhibitor suberoylanilide hydroxamic acid (SAHA). These data suggest that it may be possible to develop HDAC inhibitors that target multiple malaria parasite life cycle stages. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  11. Normalization of time-series satellite reflectance data to a standard sun-target-sensor geometry using a semi-empirical model

    Science.gov (United States)

    Zhao, Yongguang; Li, Chuanrong; Ma, Lingling; Tang, Lingli; Wang, Ning; Zhou, Chuncheng; Qian, Yonggang

    2017-10-01

    Time series of satellite reflectance data have been widely used to characterize environmental phenomena, describe trends in vegetation dynamics and study climate change. However, several sensors with wide spatial coverage and high observation frequency are usually designed to have large field of view (FOV), which cause variations in the sun-targetsensor geometry in time-series reflectance data. In this study, on the basis of semiempirical kernel-driven BRDF model, a new semi-empirical model was proposed to normalize the sun-target-sensor geometry of remote sensing image. To evaluate the proposed model, bidirectional reflectance under different canopy growth conditions simulated by Discrete Anisotropic Radiative Transfer (DART) model were used. The semi-empirical model was first fitted by using all simulated bidirectional reflectance. Experimental result showed a good fit between the bidirectional reflectance estimated by the proposed model and the simulated value. Then, MODIS time-series reflectance data was normalized to a common sun-target-sensor geometry by the proposed model. The experimental results showed the proposed model yielded good fits between the observed and estimated values. The noise-like fluctuations in time-series reflectance data was also reduced after the sun-target-sensor normalization process.

  12. Phosphorylated hydroxyethylamines as novel inhibitors of the bacterial cell wall biosynthesis enzymes MurC to MurF.

    Science.gov (United States)

    Sova, Matej; Kovac, Andreja; Turk, Samo; Hrast, Martina; Blanot, Didier; Gobec, Stanislav

    2009-12-01

    Enzymes involved in the biosynthesis of bacterial peptidoglycan represent important targets for development of new antibacterial drugs. Among them, Mur ligases (MurC to MurF) catalyze the formation of the final cytoplasmic precursor UDP-N-acetylmuramyl-pentapeptide from UDP-N-acetylmuramic acid. We present the design, synthesis and biological evaluation of a series of phosphorylated hydroxyethylamines as new type of small-molecule inhibitors of Mur ligases. We show that the phosphate group attached to the hydroxyl moiety of the hydroxyethylamine core is essential for good inhibitory activity. The IC(50) values of these inhibitors were in the micromolar range, which makes them a promising starting point for the development of multiple inhibitors of Mur ligases as potential antibacterial agents. In addition, 1-(4-methoxyphenylsulfonamido)-3-morpholinopropan-2-yl dihydrogen phosphate 7a was discovered as one of the best inhibitors of MurE described so far.

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

    Science.gov (United States)

    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.

  14. Tyrosine kinase, aurora kinase and leucine aminopeptidase as attractive drug targets in anticancer therapy - characterisation of their inhibitors.

    Science.gov (United States)

    Ziemska, Joanna; Solecka, Jolanta

    Cancers are the leading cause of deaths all over the world. Available anticancer agents used in clinics exhibit low therapeutic index and usually high toxicity. Wide spreading drug resistance of cancer cells induce a demanding need to search for new drug targets. Currently, many on-going studies on novel compounds with potent anticancer activity, high selectivity as well as new modes of action are conducted. In this work, we describe in details three enzyme groups, which are at present of extensive interest to medical researchers and pharmaceutical companies. These include receptor tyrosine kinases (e.g. EGFR enzymes) and non-receptor tyrosine kinases (Src enzymes), type A, B and C Aurora kinases and aminopeptidases, especially leucine aminopeptidase. We discuss classification of these enzymes, biochemistry as well as their role in the cell cycle under normal conditions and during cancerogenesis. Further on, the work describes enzyme inhibitors that are under in vitro, preclinical, clinical studies as well as drugs available on the market. Both, chemical structures of discovered inhibitors and the role of chemical moieties in novel drug design are discussed. Described enzymes play essential role in cell cycle, especially in mitosis (Aurora kinases), cell differentiation, growth and apoptosis (tyrosine kinases) as well as G1/S transition (leucine aminopeptidase). In cancer cells, they are overexpressed and only their inhibition may stop tumor progression. This review presents the clinical outcomes of selected inhibitors and argues the safety of drug usage in human volunteers. Clinical studies of EGFR and Src kinase inhibitors in different tumors clearly show the need for molecular selection of patients (to those with mutations in genes coding EGFR and Src) to achieve positive clinical response. Current data indicates the great necessity for new anticancer treatment and actions to limit off-target activity.

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

    Science.gov (United States)

    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

  16. Radiolabeled enzyme inhibitors and binding agents targeting PSMA: Effective theranostic tools for imaging and therapy of prostate cancer

    International Nuclear Information System (INIS)

    Pillai, Maroor Raghavan Ambikalmajan; Nanabala, Raviteja; Joy, Ajith; Sasikumar, Arun; Knapp, Furn F.

    2016-01-01

    Because of the broad incidence, morbidity and mortality associated with prostate-derived cancer, the development of more effective new technologies continues to be an important goal for the accurate detection and treatment of localized prostate cancer, lymphatic involvement and metastases. Prostate-specific membrane antigen (PSMA; Glycoprotein II) is expressed in high levels on prostate-derived cells and is an important target for visualization and treatment of prostate cancer. Radiolabeled peptide targeting technologies have rapidly evolved over the last decade and have focused on the successful development of radiolabeled small molecules that act as inhibitors to the binding of the N-acetyl-L-aspartyl-L-glutamate (NAAG) substrate to the PSMA molecule. A number of radiolabeled PSMA inhibitors have been described in the literature and labeled with SPECT, PET and therapeutic radionuclides. Clinical studies with these agents have demonstrated the improved potential of PSMA-targeted PET imaging agents to detect metastatic prostate cancer in comparison with conventional imaging technologies. Although many of these agents have been evaluated in humans, by far the most extensive clinical literature has described use of the 68 Ga and 177 Lu agents. This review describes the design and development of these agents, with a focus on the broad clinical introduction of PSMA targeting motifs labeled with 68 Ga for PET-CT imaging and 177 Lu for therapy. In particular, because of availability from the long-lived 68 Ge (T 1/2 = 270 days)/ 68 Ga (T 1/2 = 68 min) generator system and increasing availability of PET-CT, the 68 Ga-labeled PSMA targeted agent is receiving widespread interest and is one of the fastest growing radiopharmaceuticals for PET-CT imaging.

  17. Biochemical analysis of leishmanial and human GDP-Mannose Pyrophosphorylases and selection of inhibitors as new leads.

    Science.gov (United States)

    Mao, Wei; Daligaux, Pierre; Lazar, Noureddine; Ha-Duong, Tâp; Cavé, Christian; van Tilbeurgh, Herman; Loiseau, Philippe M; Pomel, Sébastien

    2017-04-07

    Leishmaniases are an ensemble of diseases caused by the protozoan parasite of the genus Leishmania. Current antileishmanial treatments are limited and present main issues of toxicity and drug resistance emergence. Therefore, the generation of new inhibitors specifically directed against a leishmanial target is an attractive strategy to expand the chemotherapeutic arsenal. GDP-Mannose Pyrophosphorylase (GDP-MP) is a prominent therapeutic target involved in host-parasite recognition which has been described to be essential for parasite survival. In this work, we produced and purified GDP-MPs from L. mexicana (LmGDP-MP), L. donovani (LdGDP-MP), and human (hGDP-MP), and compared their enzymatic properties. From a rationale design of 100 potential inhibitors, four compounds were identified having a promising and specific inhibitory effect on parasite GDP-MP and antileishmanial activities, one of them exhibits a competitive inhibition on LdGDP-MP and belongs to the 2-substituted quinoline series.

  18. Taxane-Platin-Resistant Lung Cancers Co-develop Hypersensitivity to JumonjiC Demethylase Inhibitors

    Directory of Open Access Journals (Sweden)

    Maithili P. Dalvi

    2017-05-01

    Full Text Available Although non-small cell lung cancer (NSCLC patients benefit from standard taxane-platin chemotherapy, many relapse, developing drug resistance. We established preclinical taxane-platin-chemoresistance models and identified a 35-gene resistance signature, which was associated with poor recurrence-free survival in neoadjuvant-treated NSCLC patients and included upregulation of the JumonjiC lysine demethylase KDM3B. In fact, multi-drug-resistant cells progressively increased the expression of many JumonjiC demethylases, had altered histone methylation, and, importantly, showed hypersensitivity to JumonjiC inhibitors in vitro and in vivo. Increasing taxane-platin resistance in progressive cell line series was accompanied by progressive sensitization to JIB-04 and GSK-J4. These JumonjiC inhibitors partly reversed deregulated transcriptional programs, prevented the emergence of drug-tolerant colonies from chemo-naive cells, and synergized with standard chemotherapy in vitro and in vivo. Our findings reveal JumonjiC inhibitors as promising therapies for targeting taxane-platin-chemoresistant NSCLCs.

  19. Preclinical FLT-PET and FDG-PET imaging of tumor response to the multi-targeted Aurora B kinase inhibitor, TAK-901

    International Nuclear Information System (INIS)

    Cullinane, Carleen; Waldeck, Kelly L.; Binns, David; Bogatyreva, Ekaterina; Bradley, Daniel P.; Jong, Ron de; McArthur, Grant A.; Hicks, Rodney J.

    2014-01-01

    Introduction: The Aurora kinases play a key role in mitosis and have recently been identified as attractive targets for therapeutic intervention in cancer. The aim of this study was therefore to investigate the utility of 3′-[ 18 F]fluoro-3′-deoxythymidine (FLT) and 2-deoxy-2-[ 18 F]fluoro-D-glucose (FDG) for assessment of tumor response to the multi-targeted Aurora B kinase inhibitor, TAK-901. Methods: Balb/c nude mice bearing HCT116 colorectal xenografts were treated with up to 30 mg/kg TAK 901 or vehicle intravenously twice daily for two days on a weekly cycle. Tumor growth was monitored by calliper measurements and PET imaging was performed at baseline, day 4, 8, 11 and 15. Tumors were harvested at time points corresponding to days of PET imaging for analysis of ex vivo markers of cell proliferation and metabolism together with markers of Aurora B kinase inhibition including phospho-histone H3 (pHH3) and senescence associated β-galactosidase. Results: Tumor growth was inhibited by 60% on day 12 of 30 mg/kg TAK-901 therapy. FLT uptake was significantly reduced by day 4 of treatment and this corresponded with reduction in bromodeoxyuridine and pHH3 staining by immunohistochemistry. All biomarkers rebounded towards baseline levels by the commencement of the next treatment cycle, consistent with release of Aurora B kinase suppression. TAK-901 therapy had no impact on glucose metabolism as assessed by FDG uptake and GLUT1 staining by immunohistochemistry. Conclusions: FLT-PET, but not FDG-PET, is a robust non-invasive imaging biomarker of early HCT116 tumor response to the on-target effects of the multi-targeted Aurora B kinase inhibitor, TAK-901. Advances in knowledge and implications for patient care: This is the first report to demonstrate the impact of the multi-targeted Aurora B kinase inhibitor, TAK-901 on tumor FLT uptake. The findings provide a strong rationale for the evaluation of FLT-PET as an early biomarker of tumor response in the early phase

  20. 2-Aminobenzimidazoles as potent Aurora kinase inhibitors.

    Science.gov (United States)

    Zhong, Min; Bui, Minna; Shen, Wang; Baskaran, Subramanian; Allen, Darin A; Elling, Robert A; Flanagan, W Michael; Fung, Amy D; Hanan, Emily J; Harris, Shannon O; Heumann, Stacey A; Hoch, Ute; Ivy, Sheryl N; Jacobs, Jeffrey W; Lam, Stuart; Lee, Heman; McDowell, Robert S; Oslob, Johan D; Purkey, Hans E; Romanowski, Michael J; Silverman, Jeffrey A; Tangonan, Bradley T; Taverna, Pietro; Yang, Wenjin; Yoburn, Josh C; Yu, Chul H; Zimmerman, Kristin M; O'Brien, Tom; Lew, Willard

    2009-09-01

    This Letter describes the discovery and key structure-activity relationship (SAR) of a series of 2-aminobenzimidazoles as potent Aurora kinase inhibitors. 2-Aminobenzimidazole serves as a bioisostere of the biaryl urea residue of SNS-314 (1c), which is a potent Aurora kinase inhibitor and entered clinical testing in patients with solid tumors. Compared to SNS-314, this series of compounds offers better aqueous solubility while retaining comparable in vitro potency in biochemical and cell-based assays; in particular, 6m has also demonstrated a comparable mouse iv PK profile to SNS-314.

  1. Identification and characterization of the novel reversible and selective cathepsin X inhibitors.

    Science.gov (United States)

    Fonović, Urša Pečar; Mitrović, Ana; Knez, Damijan; Jakoš, Tanja; Pišlar, Anja; Brus, Boris; Doljak, Bojan; Stojan, Jure; Žakelj, Simon; Trontelj, Jurij; Gobec, Stanislav; Kos, Janko

    2017-09-13

    Cathepsin X is a cysteine peptidase involved in the progression of cancer and neurodegenerative diseases. Targeting this enzyme with selective inhibitors opens a new possibility for intervention in several therapeutic areas. In this study triazole-based reversible and selective inhibitors of cathepsin X have been identified. Their selectivity and binding is enhanced when the 2,3-dihydrobenzo[b][1,4]dioxine moiety is present as the R 1 substituent. Of a series of selected triazole-benzodioxine derivatives, compound 22 is the most potent inhibitor of cathepsin X carboxypeptidase activity (K i  = 2.45 ± 0.05 μM) with at least 100-fold greater selectivity in comparison to cathepsin B or other related cysteine peptidases. Compound 22 is not cytotoxic to prostate cancer cells PC-3 or pheochromocytoma PC-12 cells at concentrations up to 10 μM. It significantly inhibits the migration of tumor cells and increases the outgrowth of neurites, both processes being under the control of cathepsin X carboxypeptidase activity. Compound 22 and other characterized triazole-based inhibitors thus possess a great potential for further development resulting in several in vivo applications.

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

    Science.gov (United States)

    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.

  3. Development of epidermal growth factor receptor targeted therapy in pancreatic cancer.

    Science.gov (United States)

    Qing, Liu; Qing, Wang

    2018-02-01

    The epidermal growth factor receptor (EGFR) family are a series of important cancer therapeutic targets involved in cancer biology. These genes play an important role in tumor biological characteristics including angiogenesis, cell survival, invasion and glucose metabolism. In recent years, progresses have been achieved upon the cellular and molecular biological characteristics of EGFR and its role in cancer development based on the study of tumor specimens and experimental animal model. EGFR(HER1/ErbB) is overexpressed in over sixty percent of triple-negative breast cancers and occurs in pancreatic, bladder, lung and head-and-neck cancers. Up to now, EGFR inhibitors have been applied in various of cancer, such as lung, breast, bladder and head and neck cancers etc., in which the combination of EGFR inhibitors plus chemotherapeutic agents is now seen as the standard of care for advanced/metastatic pancreatic cancer. For these reasons, EGFR inhibitors and their therapeutic effect for pancreatic cancer is becoming the focus in Laboratory and clinical research. In this paper, research progress of the development of epidermal growth factor receptor targeted therapy in pancreatic cancer is introduced.

  4. Novel multi-target-directed ligands for Alzheimer's disease: Combining cholinesterase inhibitors and 5-HT6 receptor antagonists. Design, synthesis and biological evaluation.

    Science.gov (United States)

    Więckowska, Anna; Kołaczkowski, Marcin; Bucki, Adam; Godyń, Justyna; Marcinkowska, Monika; Więckowski, Krzysztof; Zaręba, Paula; Siwek, Agata; Kazek, Grzegorz; Głuch-Lutwin, Monika; Mierzejewski, Paweł; Bienkowski, Przemysław; Sienkiewicz-Jarosz, Halina; Knez, Damijan; Wichur, Tomasz; Gobec, Stanislav; Malawska, Barbara

    2016-11-29

    As currently postulated, a complex treatment may be key to an effective therapy for Alzheimer's disease (AD). Recent clinical trials in patients with moderate AD have shown a superior effect of the combination therapy of donepezil (a selective acetylcholinesterase inhibitor) with idalopirdine (a 5-HT 6 receptor antagonist) over monotherapy with donepezil. Here, we present the first report on the design, synthesis and biological evaluation of a novel class of multifunctional ligands that combines a 5-HT 6 receptor antagonist with a cholinesterase inhibitor. Novel multi-target-directed ligands (MTDLs) were designed by combining pharmacophores directed against the 5-HT 6 receptor (1-(phenylsulfonyl)-4-(piperazin-1-yl)-1H-indole) and cholinesterases (tacrine or N-benzylpiperidine analogues). In vitro evaluation led to the identification of tacrine derivative 12 with well-balanced potencies against the 5-HT 6 receptor (K b  = 27 nM), acetylcholinesterase and butyrylcholinesterase (IC 50 hAChE  = 12 nM, IC 50 hBuChE  = 29 nM). The compound also showed good in vitro blood-brain-barrier permeability (PAMPA-BBB assay), which was confirmed in vivo (open field study). Central cholinomimetic activity was confirmed in vivo in rats using a scopolamine-induced hyperlocomotion model. A novel class of multifunctional ligands with compound 12 as the best derivative in a series represents an excellent starting point for the further development of an effective treatment for AD. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. 3,4-Dimethoxyphenyl bis-benzimidazole, a novel DNA topoisomerase inhibitor that preferentially targets Escherichia coli topoisomerase I

    Science.gov (United States)

    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

  6. Design and synthesis of N-(4-aminopyridin-2-yl)amides as B-Raf(V600E) inhibitors.

    Science.gov (United States)

    Li, Xiaokai; Shen, Jiayi; Tan, Li; Zhang, Zhang; Gao, Donglin; Luo, Jinfeng; Cheng, Huimin; Zhou, Xiaoping; Ma, Jie; Ding, Ke; Lu, Xiaoyun

    2016-06-15

    B-Raf(V600E) was an effective target for the treatment of human cancers. Based on a pan-Raf inhibitor TAK-632, a series of N-(4-aminopyridin-2-yl)amide derivatives were designed as novel B-Raf(V600E) inhibitors. Detailed structure-activity studies of the compounds revealed that most of the compounds displayed potent enzymatic activity against B-Raf(V600E), and good selectivity over B-Raf(WT). One of the most promising compound 4l exhibited potent inhibitory activity with an IC50 value of 38nM for B-raf(V600E), and displayed antiproliferative activities against colo205 and HT29 cells with IC50 values of 0.136 and 0.094μM, respectively. It also displayed good selectivity on both enzymatic and cellular assays over B-Raf(WT). These inhibitors may serve as lead compounds for further developing novel B-Raf(V600E) inhibitors as anticancer drugs. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  8. Identification of novel targets for PGC-1α and histone deacetylase inhibitors in neuroblastoma cells

    International Nuclear Information System (INIS)

    Cowell, Rita M.; Talati, Pratik; Blake, Kathryn R.; Meador-Woodruff, James H.; Russell, James W.

    2009-01-01

    Recent evidence suggests that the transcriptional coactivator peroxisome proliferator activated receptor γ coactivator 1α (PGC-1α) is involved in the pathology of Huntington's Disease (HD). While animals lacking PGC-1α express lower levels of genes involved in antioxidant defense and oxidative phosphorylation in the brain, little is known about other targets for PGC-1α in neuronal cells and whether there are ways to pharmacologically target PGC-1α in neurons. Here, PGC-1α 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 3 activation. Treatment of cells with the histone deacetylase inhibitors (HDACi's) trichostatin A and valproic acid upregulated PGC-1α and glucose transporter 4 (GLUT4). These results suggest that PGC-1α regulates multiple pathways in neurons and that HDACi's may be good candidates to target PGC-1α and GLUT4 in HD and other neurological disorders.

  9. Design and Synthesis of Bis-amide and Hydrazide-containing Derivatives of Malonic Acid as Potential HIV-1 Integrase Inhibitors

    Directory of Open Access Journals (Sweden)

    Nouri Neamati

    2008-10-01

    Full Text Available HIV-1 integrase (IN is an attractive and validated target for the development of novel therapeutics against AIDS. In the search for new IN inhibitors, we designed and synthesized three series of bis-amide and hydrazide-containing derivatives of malonic acid. We performed a docking study to investigate the potential interactions of the title compounds with essential amino acids on the IN active site.

  10. FoxM1 is a general target for proteasome inhibitors.

    Directory of Open Access Journals (Sweden)

    Uppoor G Bhat

    2009-08-01

    Full Text Available Proteasome inhibitors are currently in the clinic or in clinical trials, but the mechanism of their anticancer activity is not completely understood. The oncogenic transcription factor FoxM1 is one of the most overexpressed genes in human tumors, while its expression is usually halted in normal non-proliferating cells. Previously, we established that thiazole antibiotics Siomycin A and thiostrepton inhibit FoxM1 and induce apoptosis in human cancer cells. Here, we report that Siomycin A and thiostrepton stabilize the expression of a variety of proteins, such as p21, Mcl-1, p53 and hdm-2 and also act as proteasome inhibitors in vitro. More importantly, we also found that well-known proteasome inhibitors such as MG115, MG132 and bortezomib inhibit FoxM1 transcriptional activity and FoxM1 expression. In addition, overexpression of FoxM1 specifically protects against bortezomib-, but not doxorubicin-induced apoptosis. These data suggest that negative regulation of FoxM1 by proteasome inhibitors is a general feature of these drugs and it may contribute to their anticancer properties.

  11. Structural Biology and Molecular Modeling in the Design of Novel DPP-4 Inhibitors

    Science.gov (United States)

    Scapin, Giovanna

    Inhibition of dipeptidyl peptidase IV (DPP-4) is a promising new approach for the treatment of type 2 diabetes. DPP-4 is the enzyme responsible for inactivating the incretin hormones glucagon-like peptide 1 (GLP-1) and glucose dependent insulinotropic polypeptide (GIP), two hormones that play important roles in glucose homeostasis. The potent, orally bioavailable and highly selective small molecule DPP-4 inhibitor sitagliptin has been approved by the FDA as novel drug for the treatment of type 2 diabetes. The comparison between the binding mode of sitagliptin (a β-amino acid) and that of a second class of inhibitors (α-amino acid-based) initially led to the successful identification and design of structurally diverse and highly potent DPP-4 inhibitors. Further analysis of the crystal structure of sitagliptin bound to DPP-4 suggested that the central β-amino butanoyl moiety could be replaced by a rigid group. This was confirmed by molecular modeling, and the resulting cyclohexylamine analogs were synthesized and found to be potent DPP-4 inhibitors. However, the triazolopyrazine was predicted to be distorted in order to fit in the binding pocket, and the crystal structure showed that multiple conformations exist for this moiety. Additional molecular modeling studies were then used to improve potency of the cyclohexylamine series. In addition, a 3-D QSAR method was used to gain insight for reducing off-target DPP-8/9 activities. Novel compounds were thus synthesized and found to be potent DPP-4 inhibitors. Two compounds in particular were designed to be highly selective against off-target "DPP-4 Activity- and/or Structure Homologues" (DASH) enzymes while maintaining potency against DPP-4.

  12. Structure-Guided Strategy for the Development of Potent Bivalent ERK Inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Lechtenberg, Bernhard C. [Cancer; Mace, Peter D. [Cancer; Sessions, E. Hampton [Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida 32827, United States; Williamson, Robert [Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida 32827, United States; Stalder, Romain [Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida 32827, United States; Wallez, Yann [Cancer; Roth, Gregory P. [Sanford Burnham Prebys Medical Discovery Institute at Lake Nona, Orlando, Florida 32827, United States; Riedl, Stefan J. [Cancer; Pasquale, Elena B. [Cancer; Pathology

    2017-06-13

    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 the 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.

  13. Selective and membrane-permeable small molecule inhibitors of nicotinamide N-methyltransferase reverse high fat diet-induced obesity in mice.

    Science.gov (United States)

    Neelakantan, Harshini; Vance, Virginia; Wetzel, Michael D; Wang, Hua-Yu Leo; McHardy, Stanton F; Finnerty, Celeste C; Hommel, Jonathan D; Watowich, Stanley J

    2018-01-01

    There is a critical need for new mechanism-of-action drugs that reduce the burden of obesity and associated chronic metabolic comorbidities. A potentially novel target to treat obesity and type 2 diabetes is nicotinamide-N-methyltransferase (NNMT), a cytosolic enzyme with newly identified roles in cellular metabolism and energy homeostasis. To validate NNMT as an anti-obesity drug target, we investigated the permeability, selectivity, mechanistic, and physiological properties of a series of small molecule NNMT inhibitors. Membrane permeability of NNMT inhibitors was characterized using parallel artificial membrane permeability and Caco-2 cell assays. Selectivity was tested against structurally-related methyltransferases and nicotinamide adenine dinucleotide (NAD + ) salvage pathway enzymes. Effects of NNMT inhibitors on lipogenesis and intracellular levels of metabolites, including NNMT reaction product 1-methylnicotianamide (1-MNA) were evaluated in cultured adipocytes. Effects of a potent NNMT inhibitor on obesity measures and plasma lipid were assessed in diet-induced obese mice fed a high-fat diet. Methylquinolinium scaffolds with primary amine substitutions displayed high permeability from passive and active transport across membranes. Importantly, methylquinolinium analogues displayed high selectivity, not inhibiting related SAM-dependent methyltransferases or enzymes in the NAD + salvage pathway. NNMT inhibitors reduced intracellular 1-MNA, increased intracellular NAD + and S-(5'-adenosyl)-l-methionine (SAM), and suppressed lipogenesis in adipocytes. Treatment of diet-induced obese mice systemically with a potent NNMT inhibitor significantly reduced body weight and white adipose mass, decreased adipocyte size, and lowered plasma total cholesterol levels. Notably, administration of NNMT inhibitors did not impact total food intake nor produce any observable adverse effects. These results support development of small molecule NNMT inhibitors as therapeutics to

  14. Clonal evolution of AML on novel FMS-like tyrosine kinase-3 (FLT3 inhibitor therapy with evolving actionable targets

    Directory of Open Access Journals (Sweden)

    Pashtoon M. Kasi

    2016-01-01

    Full Text Available For acute myeloid leukemia (AML, identification of activating mutations in the FMS-like tyrosine kinase-3 (FLT3 has led to the development of several FLT3-inhibitors. Here we present clinical and next generation sequencing data at the time of progression of a patient on a novel FLT3-inhibitor clinical trial (ASP2215 to show that employing therapeutic interventions with these novel targeted therapies can lead to consequences secondary to selective pressure and clonal evolution of cancer. We describe novel findings alongside data on treatment directed towards actionable aberrations acquired during the process. (Clinical Trial: NCT02014558; registered at: 〈https://clinicaltrials.gov/ct2/show/NCT02014558〉

  15. A potent series targeting the malarial cGMP-dependent protein kinase clears infection and blocks transmission

    NARCIS (Netherlands)

    Baker, D.A.; Stewart, L.B.; Large, J.M.; Bowyer, P.W.; Ansell, K.H.; Jimenez-Diaz, M.B.; Bakkouri, M. El; Birchall, K.; Dechering, K.J.; Bouloc, N.S.; Coombs, P.J.; Whalley, D.; Harding, D.J.; Smiljanic-Hurley, E.; Wheldon, M.C.; Walker, E.M.; Dessens, J.T.; Lafuente, M.J.; Sanz, L.M.; Gamo, F.J.; Ferrer, S.B.; Hui, R.; Bousema, T.; Angulo-Barturen, I.; Merritt, A.T.; Croft, S.L.; Gutteridge, W.E.; Kettleborough, C.A.; Osborne, S.A.

    2017-01-01

    To combat drug resistance, new chemical entities are urgently required for use in next generation anti-malarial combinations. We report here the results of a medicinal chemistry programme focused on an imidazopyridine series targeting the Plasmodium falciparum cyclic GMP-dependent protein kinase

  16. New 5-benzylidenethiazolidin-4-one inhibitors of bacterial MurD ligase: design, synthesis, crystal structures, and biological evaluation.

    Science.gov (United States)

    Zidar, Nace; Tomašić, Tihomir; Šink, Roman; Kovač, Andreja; Patin, Delphine; Blanot, Didier; Contreras-Martel, Carlos; Dessen, Andréa; Premru, Manica Müller; Zega, Anamarija; Gobec, Stanislav; Mašič, Lucija Peterlin; Kikelj, Danijel

    2011-11-01

    Mur ligases (MurC-MurF), a group of bacterial enzymes that catalyze four consecutive steps in the formation of cytoplasmic peptidoglycan precursor, are becoming increasingly adopted as targets in antibacterial drug design. Based on the crystal structure of MurD cocrystallized with thiazolidine-2,4-dione inhibitor I, we have designed, synthesized, and evaluated a series of improved glutamic acid containing 5-benzylidenerhodanine and 5-benzylidenethiazolidine-2,4-dione inhibitors of MurD with IC(50) values up to 28 μM. Inhibitor 37, with an IC(50) of 34 μM, displays a weak antibacterial activity against S. aureus ATCC 29213 and E. faecalis ATCC 29212 with minimal inhibitory concentrations of 128 μg/mL. High-resolution crystal structures of MurD in complex with two new inhibitors (compounds 23 and 51) reveal details of their binding modes within the active site and provide valuable information for further structure-based optimization. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  17. Virtual screening filters for the design of type II p38 MAP kinase inhibitors: a fragment based library generation approach.

    Science.gov (United States)

    Badrinarayan, Preethi; Sastry, G Narahari

    2012-04-01

    In this work, we introduce the development and application of a three-step scoring and filtering procedure for the design of type II p38 MAP kinase leads using allosteric fragments extracted from virtual screening hits. The design of the virtual screening filters is based on a thorough evaluation of docking methods, DFG-loop conformation, binding interactions and chemotype specificity of the 138 p38 MAP kinase inhibitors from Protein Data Bank bound to DFG-in and DFG-out conformations using Glide, GOLD and CDOCKER. A 40 ns molecular dynamics simulation with the apo, type I with DFG-in and type II with DFG-out forms was carried out to delineate the effects of structural variations on inhibitor binding. The designed docking-score and sub-structure filters were first tested on a dataset of 249 potent p38 MAP kinase inhibitors from seven diverse series and 18,842 kinase inhibitors from PDB, to gauge their capacity to discriminate between kinase and non-kinase inhibitors and likewise to selectively filter-in target-specific inhibitors. The designed filters were then applied in the virtual screening of a database of ten million (10⁷) compounds resulting in the identification of 100 hits. Based on their binding modes, 98 allosteric fragments were extracted from the hits and a fragment library was generated. New type II p38 MAP kinase leads were designed by tailoring the existing type I ATP site binders with allosteric fragments using a common urea linker. Target specific virtual screening filters can thus be easily developed for other kinases based on this strategy to retrieve target selective compounds. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Target sites for chemical regulation of strigolactone signaling

    Directory of Open Access Journals (Sweden)

    Hidemitsu eNakamura

    2014-11-01

    Full Text Available Demands for plant growth regulators (chemicals that control plant growth are increasing globally, especially in developing countries. Both positive and negative plant growth regulators are widely used to enhance crop production and to suppress unwanted shoot growth, respectively. Strigolactones (SLs are multifunctional molecules that function as phytohormones, inhibiting shoot branching and also functioning in the rhizospheric communication with symbiotic fungi and parasitic weeds. Therefore, it is anticipated that chemicals that regulate the functions of SLs will be widely used in agricultural applications. Although the SL biosynthetic pathway is not fully understood, it has been demonstrated that beta-carotene isomerases, carotenoid cleavage dioxygenases (CCDs, and a cytochrome P450 monooxygenase are involved in strigolactone biosynthesis. A CCD inhibitor, abamine, which is also an inhibitor of abscisic acid biosynthesis, reduces the levels of SL in several plant species and reduces the germination rate of Orobanche minor seeds grown with tobacco. On the basis of the structure of abamine, several chemicals have been designed to specifically inhibit CCDs during SL synthesis. Cytochrome P450 monooxygenase is another target enzyme in the development of SL biosynthesis inhibitors, and the triazole-derived TIS series of chemicals is known to include SL biosynthesis inhibitors, although their target enzyme has not been identified. Recently, DWARF14 (D14 has been shown to be a receptor for SLs, and the D-ring moiety of SL is essential for its recognition by D14. A variety of SL agonists are currently under development and most agonists commonly contain the D-ring or a D-ring-like moiety. Several research groups have also resolved the crystal structure of D14 in the last two years. It is expected that this information on the D14 structure will be invaluable not only for developing SL agonists with novel structures but also in the design of inhibitors

  19. Benzo[g]quinazolin-based scaffold derivatives as dual EGFR/HER2 inhibitors.

    Science.gov (United States)

    Ghorab, Mostafa M; Alsaid, Mansour S; Soliman, Aiten M; Al-Mishari, Abdullah A

    2018-12-01

    Targeting EGFR has proven to be beneficial in the treatment of several types of solid tumours. So, a series of novel 2-(4-oxo-3-(4-sulfamoylphenyl)-3,4-dihydrobenzo[g]quinazolin-2-ylthio)-N-substituted acetamide 5-19 were synthesised from the starting material 4-(2-mercapto-4-oxobenzo[g]quinazolin-3(4H)-yl) benzenesulfonamide 4, to be evaluated as dual EGFR/HER2 inhibitors. The target compounds 5-19, were screened for their cytotoxic activity against A549 lung cancer cell line. The percentage inhibition of EGFR enzyme was measured and compared with erlotinib as the reference drug. Compounds 6, 8, 10, and 16 showed excellent EGFR inhibitory activity and were further selected for screening as dual EGFR/HER2 inhibitors. The four selected compounds showed IC 50 ranging from 0.009 to 0.026 µM for EGFR and 0.021 to 0.069 µM for the HER2 enzyme. Compound 8 was found to be the most potent in this study with IC 50 0.009 and 0.021 µM for EGFR and HER2, respectively.

  20. Targeting the Wnt/beta-catenin pathway in cancer: Update on effectors and inhibitors.

    Science.gov (United States)

    Krishnamurthy, Nithya; Kurzrock, Razelle

    2018-01-01

    The Wnt/beta-catenin pathway is a family of proteins that is implicated in many vital cellular functions such as stem cell regeneration and organogenesis. Several intra-cellular signal transduction pathways are induced by Wnt, notably the Wnt/beta-catenin dependent pathway or canonical pathway and the non-canonical or beta-catenin-independent pathway; the latter includes the Wnt/Ca2+ and Planar Cell Polarity pathway (PCP). Wnt activation occurs at the intestinal crypt floor, and is critical to optimal maintenance of stem cells. Colorectal cancers show evidence of Wnt signaling pathway activation and this is associated with loss of function of the tumor regulator APC. Wnt activation has been observed in breast, lung, and hematopoietic malignancies and contributes to tumor recurrence. The Wnt pathway cross talks with the Notch and Sonic Hedgehog pathways, which has implications for therapeutic interventions in cancers. There are significant challenges in targeting the Wnt pathway, including finding agents that are efficacious without damaging the system of normal somatic stem cell function in cellular repair and tissue homeostasis. Here, we comprehensively review the Wnt pathway and its interactions with the Notch and Sonic Hedgehog pathways. We present the state of the field in effectors and inhibitors of Wnt signaling, including updates on clinical trials in various cancers with inhibitors of Wnt, Notch, and Sonic Hedgehog. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. A kinase inhibitor screen identifies Mcl-1 and Aurora kinase A as novel treatment targets in antiestrogen-resistant breast cancer cells

    DEFF Research Database (Denmark)

    Thrane, S; Pedersen, A M; Thomsen, M B H

    2015-01-01

    Antiestrogen resistance is a major problem in breast cancer treatment. Therefore, the search for new therapeutic targets and biomarkers for antiestrogen resistance is crucial. In this study, we performed a kinase inhibitor screen on antiestrogen responsive MCF-7 cells and a panel of MCF-7-derived...

  2. Structure-Guided Discovery of Novel, Potent, and Orally Bioavailable Inhibitors of Lipoprotein-Associated Phospholipase A2.

    Science.gov (United States)

    Liu, Qiufeng; Huang, Fubao; Yuan, Xiaojing; Wang, Kai; Zou, Yi; Shen, Jianhua; Xu, Yechun

    2017-12-28

    Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a promising therapeutic target for atherosclerosis, Alzheimer's disease, and diabetic macular edema. Here we report the identification of novel sulfonamide scaffold Lp-PLA2 inhibitors derived from a relatively weak fragment. Similarity searching on this fragment followed by molecular docking leads to the discovery of a micromolar inhibitor with a 300-fold potency improvement. Subsequently, by the application of a structure-guided design strategy, a successful hit-to-lead optimization was achieved and a number of Lp-PLA2 inhibitors with single-digit nanomolar potency were obtained. After preliminary evaluation of the properties of drug-likeness in vitro and in vivo, compound 37 stands out from this congeneric series of inhibitors for good inhibitory activity and favorable oral bioavailability in male Sprague-Dawley rats, providing a quality candidate for further development. The present study thus clearly demonstrates the power and advantage of integrally employing fragment screening, crystal structures determination, virtual screening, and medicinal chemistry in an efficient lead discovery project, providing a good example for structure-based drug design.

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

    Science.gov (United States)

    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

  4. The potency and specificity of the interaction between the IA3 inhibitor and its target aspartic proteinase from Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Phylip, L H; Lees, W E; Brownsey, B G

    2001-01-01

    The yeast IA3 polypeptide consists of only 68 residues, and the free inhibitor has little intrinsic secondary structure. IA3 showed subnanomolar potency toward its target, proteinase A from Saccharomyces cerevisiae, and did not inhibit any of a large number of aspartic proteinases with similar...... by the nontarget aspartic proteinases, it was not cleaved by proteinase A. The random coil IA3 polypeptide escapes cleavage by being stabilized in a helical conformation upon interaction with the active site of proteinase A. This results, paradoxically, in potent selective inhibition of the target enzyme....

  5. Bis(morpholino-1,3,5-triazine) derivatives: potent adenosine 5'-triphosphate competitive phosphatidylinositol-3-kinase/mammalian target of rapamycin inhibitors: discovery of compound 26 (PKI-587), a highly efficacious dual inhibitor.

    Science.gov (United States)

    Venkatesan, Aranapakam M; Dehnhardt, Christoph M; Delos Santos, Efren; Chen, Zecheng; Dos Santos, Osvaldo; Ayral-Kaloustian, Semiramis; Khafizova, Gulnaz; Brooijmans, Natasja; Mallon, Robert; Hollander, Irwin; Feldberg, Larry; Lucas, Judy; Yu, Ker; Gibbons, James; Abraham, Robert T; Chaudhary, Inder; Mansour, Tarek S

    2010-03-25

    The PI3K/Akt signaling pathway is a key pathway in cell proliferation, growth, survival, protein synthesis, and glucose metabolism. It has been recognized recently that inhibiting this pathway might provide a viable therapy for cancer. A series of bis(morpholino-1,3,5-triazine) derivatives were prepared and optimized to provide the highly efficacious PI3K/mTOR inhibitor 1-(4-{[4-(dimethylamino)piperidin-1-yl]carbonyl}phenyl)-3-[4-(4,6-dimorpholin-4-yl-1,3,5-triazin-2-yl)phenyl]urea 26 (PKI-587). Compound 26 has shown excellent activity in vitro and in vivo, with antitumor efficacy in both subcutaneous and orthotopic xenograft tumor models when administered intravenously. The structure-activity relationships and the in vitro and in vivo activity of analogues in this series are described.

  6. Hepatitis C Virus NS3 Inhibitors: Current and Future Perspectives

    Directory of Open Access Journals (Sweden)

    Kazi Abdus Salam

    2013-01-01

    Full Text Available Currently, hepatitis C virus (HCV infection is considered a serious health-care problem all over the world. A good number of direct-acting antivirals (DAAs against HCV infection are in clinical progress including NS3-4A protease inhibitors, RNA-dependent RNA polymerase inhibitors, and NS5A inhibitors as well as host targeted inhibitors. Two NS3-4A protease inhibitors (telaprevir and boceprevir have been recently approved for the treatment of hepatitis C in combination with standard of care (pegylated interferon plus ribavirin. The new therapy has significantly improved sustained virologic response (SVR; however, the adverse effects associated with this therapy are still the main concern. In addition to the emergence of viral resistance, other targets must be continually developed. One such underdeveloped target is the helicase portion of the HCV NS3 protein. This review article summarizes our current understanding of HCV treatment, particularly with those of NS3 inhibitors.

  7. Quantitative high-throughput screening identifies 8-hydroxyquinolines as cell-active histone demethylase inhibitors.

    Directory of Open Access Journals (Sweden)

    Oliver N F King

    2010-11-01

    Full Text Available Small molecule modulators of epigenetic processes are currently sought as basic probes for biochemical mechanisms, and as starting points for development of therapeutic agents. N(ε-Methylation of lysine residues on histone tails is one of a number of post-translational modifications that together enable transcriptional regulation. Histone lysine demethylases antagonize the action of histone methyltransferases in a site- and methylation state-specific manner. N(ε-Methyllysine demethylases that use 2-oxoglutarate as co-factor are associated with diverse human diseases, including cancer, inflammation and X-linked mental retardation; they are proposed as targets for the therapeutic modulation of transcription. There are few reports on the identification of templates that are amenable to development as potent inhibitors in vivo and large diverse collections have yet to be exploited for the discovery of demethylase inhibitors.High-throughput screening of a ∼236,000-member collection of diverse molecules arrayed as dilution series was used to identify inhibitors of the JMJD2 (KDM4 family of 2-oxoglutarate-dependent histone demethylases. Initial screening hits were prioritized by a combination of cheminformatics, counterscreening using a coupled assay enzyme, and orthogonal confirmatory detection of inhibition by mass spectrometric assays. Follow-up studies were carried out on one of the series identified, 8-hydroxyquinolines, which were shown by crystallographic analyses to inhibit by binding to the active site Fe(II and to modulate demethylation at the H3K9 locus in a cell-based assay.These studies demonstrate that diverse compound screening can yield novel inhibitors of 2OG dependent histone demethylases and provide starting points for the development of potent and selective agents to interrogate epigenetic regulation.

  8. Novel diamide-based inhibitors of IMPDH.

    Science.gov (United States)

    Gu, Henry H; Iwanowicz, Edwin J; Guo, Junqing; Watterson, Scott H; Shen, Zhongqi; Pitts, William J; Dhar, T G Murali; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Witmer, Mark; Tredup, Jeffrey; Hollenbaugh, Diane

    2002-05-06

    A series of novel amide-based small molecule inhibitors of inosine monophosphate dehydrogenase is described. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are presented.

  9. Synthesis of a new series of dithiocarbamates with effective human carbonic anhydrase inhibitory activity and antiglaucoma action.

    Science.gov (United States)

    Bozdag, Murat; Carta, Fabrizio; Vullo, Daniela; Akdemir, Atilla; Isik, Semra; Lanzi, Cecilia; Scozzafava, Andrea; Masini, Emanuela; Supuran, Claudiu T

    2015-05-15

    A new series of dithiocarbamates (DTCs) was prepared from primary/secondary amines incorporating amino/hydroxyl-alkyl, mono- and bicyclic aliphatic ring systems based on the quinuclidine, piperidine, hydroxy-/carboxy-/amino-substituted piperidine, morpholine and piperazine scaffolds, and carbon disulfide. The compounds were investigated for the inhibition of four mammalian α-carbonic anhydrases (CAs, EC 4.2.1.1) of pharmacologic relevance, that is, the human (h) hCA I, II, IX and XII, drug targets for antiglaucoma (hCA II and XII) or antitumor (hCA IX/XII) agents. The compounds were moderate or inefficient hCA I inhibitors (off-target isoform for both applications), efficiently inhibited hCA II, whereas some of them were low nanomolar/subnanomolar hCA IX/XII inhibitors. One DTC showed excellent intraocular pressure (IOP) lowering properties in an animal model of glaucoma, with a two times better efficiency compared to the clinically used sulfonamide dorzolamide. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Targeting Homologous Recombination by Pharmacological Inhibitors Enhances the Killing Response of Glioblastoma Cells Treated with Alkylating Drugs.

    Science.gov (United States)

    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.

  11. Insight into the Selectivity of the G7-18NATE Inhibitor Peptide for the Grb7-SH2 Domain Target.

    Science.gov (United States)

    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.

  12. Insight into the Selectivity of the G7-18NATE Inhibitor Peptide for the Grb7-SH2 Domain Target

    Directory of Open Access Journals (Sweden)

    Gabrielle M. Watson

    2017-09-01

    Full Text Available 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.

  13. Insight into the Selectivity of the G7-18NATE Inhibitor Peptide for the Grb7-SH2 Domain Target

    Science.gov (United States)

    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

  14. Active site-targeted covalent irreversible inhibitors of USP7 impair the functions of Foxp3+ T-regulatory cells by promoting ubiquitination of Tip60.

    Directory of Open Access Journals (Sweden)

    Feng Wang

    Full Text Available Accumulation of Foxp3+ T-regulatory (Treg cells in the tumor microenvironment is associated with tumor immune evasion and poor patient outcome in the case of many solid tumors. Current therapeutic strategies for blocking Treg functions are not Treg-specific, and display only modest and transient efficacy. Recent studies revealed that ubiquitin-specific protease 7 (USP7 is essential for Treg functions by stabilizing expression of Tip60 and Foxp3, which together are central to the development and maintenance of the Treg cell lineage. Pharmacological inhibition of USP7 is therefore a promising strategy for suppressing Treg functions and promoting anti-tumor immunity. Previously, we reported the P5091 series of small molecule USP7 inhibitors and demonstrated their direct anti-tumor activity in vivo using xenograft models. However, the precise mechanism of action of these compounds was not well defined. In this study, we report the development and characterization of P217564, a second-generation USP7 inhibitor with improved potency and selectivity. P217564 selectively targets the catalytic cleft of USP7 and modifies its active site cysteine (C223 by forming a covalent adduct. Irreversible inhibition of USP7 results in durable downstream biological responses in cells, including down-regulation of Tip60 and consequent impairment of Treg suppressive function. In addition, we demonstrate that both USP7 and various USP7 substrates are subjected to Lys48-mediated ubiquitin modification, consistent with increased proteasomal degradation of these proteins because of USP7 inhibition.

  15. A comprehensive target selectivity survey of the BCR-ABL kinase inhibitor INNO-406 by kinase profiling and chemical proteomics in chronic myeloid leukemia cells.

    Science.gov (United States)

    Rix, U; Remsing Rix, L L; Terker, A S; Fernbach, N V; Hantschel, O; Planyavsky, M; Breitwieser, F P; Herrmann, H; Colinge, J; Bennett, K L; Augustin, M; Till, J H; Heinrich, M C; Valent, P; Superti-Furga, G

    2010-01-01

    Resistance to the BCR-ABL tyrosine kinase inhibitor imatinib poses a pressing challenge in treating chronic myeloid leukemia (CML). This resistance is often caused by point mutations in the ABL kinase domain or by overexpression of LYN. The second-generation BCR-ABL inhibitor INNO-406 is known to inhibit most BCR-ABL mutants and LYN efficiently. Knowledge of its full target spectrum would provide the molecular basis for potential side effects or suggest novel therapeutic applications and possible combination therapies. We have performed an unbiased chemical proteomics native target profile of INNO-406 in CML cells combined with functional assays using 272 recombinant kinases thereby identifying several new INNO-406 targets. These include the kinases ZAK, DDR1/2 and various ephrin receptors. The oxidoreductase NQO2, inhibited by both imatinib and nilotinib, is not a relevant target of INNO-406. Overall, INNO-406 has an improved activity over imatinib but a slightly broader target profile than both imatinib and nilotinib. In contrast to dasatinib and bosutinib, INNO-406 does not inhibit all SRC kinases and most TEC family kinases and is therefore expected to elicit fewer side effects. Altogether, these properties may make INNO-406 a valuable component in the drug arsenal against CML.

  16. Rhodium(II) Proximity-Labeling Identifies a Novel Target Site on STAT3 for Inhibitors with Potent Anti-Leukemia Activity.

    Science.gov (United States)

    Minus, Matthew B; Liu, Wei; Vohidov, Farrukh; Kasembeli, Moses M; Long, Xin; Krueger, Michael J; Stevens, Alexandra; Kolosov, Mikhail I; Tweardy, David J; Sison, Edward Allan R; Redell, Michele S; Ball, Zachary T

    2015-10-26

    Nearly 40 % of children with acute myeloid leukemia (AML) suffer relapse arising from chemoresistance, often involving upregulation of the oncoprotein STAT3 (signal transducer and activator of transcription 3). Herein, 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. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Structure-Activity Relationships of the Human Immunodeficiency Virus Type 1 Maturation Inhibitor PF-46396.

    Science.gov (United States)

    Murgatroyd, Christopher; Pirrie, Lisa; Tran, Fanny; Smith, Terry K; Westwood, Nicholas J; Adamson, Catherine S

    2016-09-15

    HIV-1 maturation inhibitors are a novel class of antiretroviral compounds that consist of two structurally distinct chemical classes: betulinic acid derivatives and the pyridone-based compound PF-46396. It is currently believed that both classes act by similar modes of action to generate aberrant noninfectious particles via inhibition of CA-SP1 cleavage during Gag proteolytic processing. In this study, we utilized a series of novel analogues with decreasing similarity to PF-46396 to determine the chemical groups within PF-46396 that contribute to antiviral activity, Gag binding, and the relationship between these essential properties. A spectrum of antiviral activity (active, intermediate, and inactive) was observed across the analogue series with respect to CA-SP1 cleavage and HIV-1 (NL4-3) replication kinetics in Jurkat T cells. We demonstrate that selected inactive analogues are incorporated into wild-type (WT) immature particles and that one inactive analogue is capable of interfering with PF-46396 inhibition of CA-SP1 cleavage. Mutations that confer PF-46396 resistance can impose a defective phenotype on HIV-1 that can be rescued in a compound-dependent manner. Some inactive analogues retained the capacity to rescue PF-46396-dependent mutants (SP1-A3V, SP1-A3T, and CA-P157S), implying that they can also interact with mutant Gag. The structure-activity relationships observed in this study demonstrate that (i) the tert-butyl group is essential for antiviral activity but is not an absolute requirement for Gag binding, (ii) the trifluoromethyl group is optimal but not essential for antiviral activity, and (iii) the 2-aminoindan group is important for antiviral activity and Gag binding but is not essential, as its replacement is tolerated. Combinations of antiretroviral drugs successfully treat HIV/AIDS patients; however, drug resistance problems make the development of new mechanistic drug classes an ongoing priority. HIV-1 maturation inhibitors are novel as they

  18. Series-nonuniform rational B-spline signal feedback: From chaos to any embedded periodic orbit or target point

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Chenxi, E-mail: cxshao@ustc.edu.cn; Xue, Yong; Fang, Fang; Bai, Fangzhou [Department of Computer Science and Technology, University of Science and Technology of China, Hefei 230027 (China); Yin, Peifeng [Department of Computer Science and Engineering, Pennsylvania State University, State College, Pennsylvania 16801 (United States); Wang, Binghong [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

    2015-07-15

    The self-controlling feedback control method requires an external periodic oscillator with special design, which is technically challenging. This paper proposes a chaos control method based on time series non-uniform rational B-splines (SNURBS for short) signal feedback. It first builds the chaos phase diagram or chaotic attractor with the sampled chaotic time series and any target orbit can then be explicitly chosen according to the actual demand. Second, we use the discrete timing sequence selected from the specific target orbit to build the corresponding external SNURBS chaos periodic signal, whose difference from the system current output is used as the feedback control signal. Finally, by properly adjusting the feedback weight, we can quickly lead the system to an expected status. We demonstrate both the effectiveness and efficiency of our method by applying it to two classic chaotic systems, i.e., the Van der Pol oscillator and the Lorenz chaotic system. Further, our experimental results show that compared with delayed feedback control, our method takes less time to obtain the target point or periodic orbit (from the starting point) and that its parameters can be fine-tuned more easily.

  19. Series-nonuniform rational B-spline signal feedback: From chaos to any embedded periodic orbit or target point.

    Science.gov (United States)

    Shao, Chenxi; Xue, Yong; Fang, Fang; Bai, Fangzhou; Yin, Peifeng; Wang, Binghong

    2015-07-01

    The self-controlling feedback control method requires an external periodic oscillator with special design, which is technically challenging. This paper proposes a chaos control method based on time series non-uniform rational B-splines (SNURBS for short) signal feedback. It first builds the chaos phase diagram or chaotic attractor with the sampled chaotic time series and any target orbit can then be explicitly chosen according to the actual demand. Second, we use the discrete timing sequence selected from the specific target orbit to build the corresponding external SNURBS chaos periodic signal, whose difference from the system current output is used as the feedback control signal. Finally, by properly adjusting the feedback weight, we can quickly lead the system to an expected status. We demonstrate both the effectiveness and efficiency of our method by applying it to two classic chaotic systems, i.e., the Van der Pol oscillator and the Lorenz chaotic system. Further, our experimental results show that compared with delayed feedback control, our method takes less time to obtain the target point or periodic orbit (from the starting point) and that its parameters can be fine-tuned more easily.

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

    Science.gov (United States)

    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.

  1. High heat flux tests of the WENDELSTEIN 7-X pre-series target elements - experimental evaluation of the thermo-mechanical behaviour

    International Nuclear Information System (INIS)

    Greuner, H.; Boeswirth, B.; Boscary, J.; Plankensteiner, A.; Schedler, B.

    2006-01-01

    The HHF testing of WENDELSTEIN 7-X pre-series target elements is an indispensable step in the qualification of the manufacturing process. The finally 890 divertor target elements are made of an actively water-cooled CuCrZr heat sink covered with flat tiles of CFC NB31 as plasma facing material. A set of 20 full scale pre-series elements was manufactured by PLANSEE to validate the materials and manufacturing technologies prior to the start of the series production. Due to the large mismatch in the coefficients of thermal expansion for CFC and CuCrZr - resulting in high residual stresses as well as high operation-induced stresses - the bonding zone between CFC and CuCrZr was detected to be the most critical issue for the operational behaviour of the target elements. To achieve a sufficiently high manufacturing quality together with a high lifetime during operation thermal testing of full scale mockups was performed in combination with extensive FEM analyses. In both cases heat loads were applied similar to the expected heat loads in W7-X. All pre-series elements were tested in the ion beam test facility GLADIS. The elements were tested with 100 cycles of 10 MW/m 2 and several elements with even higher cycle numbers and heat loads up to 24 MW/m 2 . The instrumentation of the targets (thermocouples, strain gages) and the infrared camera observation of the heat loaded surface allow an experimental evaluation of the thermo-mechanical behaviour of the tested elements. The main result is a good agreement between experimental data and numerically computed predictions. Hot spots were, however, observed at the edges of several tiles during the HHF tests indicating local bonding problems. Therefore, a programme of fully 3D nonlinear thermal-mechanical FEM calculations was started to evaluate the thermo-mechanical behavior of the target elements with special focus on the optimization of the stress situation in the bonding zone between the CFC and the CuCrZr heat sink. This

  2. Suppression of tau propagation using an inhibitor that targets the DK-switch of nSMase2.

    Science.gov (United States)

    Bilousova, Tina; Elias, Chris; Miyoshi, Emily; Alam, Mohammad Parvez; Zhu, Chunni; Campagna, Jesus; Vadivel, Kanagasabai; Jagodzinska, Barbara; Gylys, Karen Hoppens; John, Varghese

    2018-05-23

    Targeting of molecular pathways involved in the cell-to-cell propagation of pathological tau species is a novel approach for development of disease-modifying therapies that could block tau pathology and attenuate cognitive decline in patients with Alzheimer's disease and other tauopathies. We discovered cambinol through a screening effort and show that it is an inhibitor of cell-to-cell tau propagation. Our in vitro data demonstrate that cambinol inhibits neutral sphingomyelinase 2 (nSMase2) enzyme activity in dose response fashion, and suppresses extracellular vesicle (EV) production while reducing tau seed propagation. Our in vivo testing with cambinol shows that it can reduce the nSMase2 activity in the brain after oral administration. Our molecular docking and simulation analysis reveals that cambinol can target the DK-switch in the nSMase2 active site. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. Discovery and preclinical pharmacology of a selective ATP-competitive Akt inhibitor (GDC-0068) for the treatment of human tumors.

    Science.gov (United States)

    Blake, James F; Xu, Rui; Bencsik, Josef R; Xiao, Dengming; Kallan, Nicholas C; Schlachter, Stephen; Mitchell, Ian S; Spencer, Keith L; Banka, Anna L; Wallace, Eli M; Gloor, Susan L; Martinson, Matthew; Woessner, Richard D; Vigers, Guy P A; Brandhuber, Barbara J; Liang, Jun; Safina, Brian S; Li, Jun; Zhang, Birong; Chabot, Christine; Do, Steven; Lee, Leslie; Oeh, Jason; Sampath, Deepak; Lee, Brian B; Lin, Kui; Liederer, Bianca M; Skelton, Nicholas J

    2012-09-27

    The discovery and optimization of a series of 6,7-dihydro-5H-cyclopenta[d]pyrimidine compounds that are ATP-competitive, selective inhibitors of protein kinase B/Akt is reported. The initial design and optimization was guided by the use of X-ray structures of inhibitors in complex with Akt1 and the closely related protein kinase A. The resulting compounds demonstrate potent inhibition of all three Akt isoforms in biochemical assays and poor inhibition of other members of the cAMP-dependent protein kinase/protein kinase G/protein kinase C extended family and block the phosphorylation of multiple downstream targets of Akt in human cancer cell lines. Biological studies with one such compound, 28 (GDC-0068), demonstrate good oral exposure resulting in dose-dependent pharmacodynamic effects on downstream biomarkers and a robust antitumor response in xenograft models in which the phosphatidylinositol 3-kinase-Akt-mammalian target of rapamycin pathway is activated. 28 is currently being evaluated in human clinical trials for the treatment of cancer.

  4. Three-dimensional quantitative structure-permeability relationship analysis for a series of inhibitors of rhinovirus replication.

    Science.gov (United States)

    Ekins, S; Durst, G L; Stratford, R E; Thorner, D A; Lewis, R; Loncharich, R J; Wikel, J H

    2001-01-01

    Multiple three-dimensional quantitative structure-activity relationship (3D-QSAR) approaches were applied to predicting passive Caco-2 permeability for a series of 28 inhibitors of rhinovirus replication. Catalyst, genetic function approximation (GFA) with MS-WHIM descriptors, CoMFA, and VolSurf were all used for generating 3D-quantitative structure permeability relationships utilizing a training set of 19 molecules. Each of these approaches was then compared using a test set of nine molecules not present in the training set. Statistical parameters for the test set predictions (r(2) and leave-one-out q(2)) were used to compare the models. It was found that the Catalyst pharmacophore model was the most predictive (test set of predicted versus observed permeability, r(2) = 0.94). This model consisted of a hydrogen bond acceptor, hydrogen bond donor, and ring aromatic feature with a training set correlation of r(2) = 0.83. The CoMFA model consisted of three components with an r(2) value of 0.96 and produced good predictions for the test set (r(2) = 0.84). VolSurf resulted in an r(2) value of 0.76 and good predictions for the test set (r(2) = 0.83). Test set predictions with GFA/WHIM descriptors (r(2) = 0.46) were inferior when compared with the Catalyst, CoMFA, and VolSurf model predictions in this evaluation. In summary it would appear that the 3D techniques have considerable value in predicting passive permeability for a congeneric series of molecules, representing a valuable asset for drug discovery.

  5. A historical overview of protein kinases and their targeted small molecule inhibitors.

    Science.gov (United States)

    Roskoski, Robert

    2015-10-01

    catalytic subunits. PKA and all other protein kinase domains have a small amino-terminal lobe and large carboxyterminal lobe as determined by X-ray crystallography. The N-lobe and C-lobe form a cleft that serves as a docking site for MgATP. Nearly all active protein kinases contain a K/E/D/D signature sequence that plays important structural and catalytic roles. Protein kinases contain hydrophobic catalytic and regulatory spines and collateral shell residues that are required to assemble the active enzyme. There are two general kinds of conformational changes associated with most protein kinases. The first conformational change involves the formation of an intact regulatory spine to form an active enzyme. The second conformational change occurs in active kinases as they toggle between open and closed conformations during their catalytic cycles. Because mutations and dysregulation of protein kinases play causal roles in human disease, this family of enzymes has become one of the most important drug targets over the past two decades. Imatinib was approved by the United States FDA for the treatment of chronic myelogenous leukemia in 2001; this small molecule inhibits the BCR-Abl protein kinase oncoprotein that results from the formation of the Philadelphia chromosome. More than two dozen other orally effective mechanism-based small molecule protein kinase inhibitors have been subsequently approved by the FDA. These drugs bind to the ATP-binding site of their target enzymes and extend into nearby hydrophobic pockets. Most of these protein kinase inhibitors prolong survival in cancer patients only weeks or months longer than standard cytotoxic therapies. In contrast, the clinical effectiveness of imatinib against chronic myelogenous leukemia is vastly superior to that of any other targeted protein kinase inhibitor with overall survival lasting a decade or more. However, the near universal and expected development of drug resistance in the treatment of neoplastic disorders

  6. Determination of human serum alpha1-acid glycoprotein and albumin binding of various marketed and preclinical kinase inhibitors.

    Science.gov (United States)

    Zsila, Ferenc; Fitos, Ilona; Bencze, Gyula; Kéri, György; Orfi, László

    2009-01-01

    There are about 380 protein kinase inhibitors in drug development as of today and 15 drugs have been marketed already for the treatment of cancer. This time 139 validated kinase targets are in the focus of drug research of pharmaceutical companies and big efforts are made for the development of new, druglike kinase inhibitors. Plasma protein binding is an important factor of the ADME profiling of a drug compound. Human serum albumin (HSA) and alpha(1)-acid glycoprotein (AAG) are the most relevant drug carriers in blood plasma. Since previous literature data indicated that AAG is the principal plasma binding component of some kinase inhibitors the present work focuses on the comprehensive evaluation of AAG binding of a series of marketed and experimental kinase inhibitors by using circular dichroism (CD) spectroscopy approach. HSA binding was also evaluated by affinity chromatography. Protein binding interactions of twenty-six kinase inhibitors are characterized. The contribution of AAG and HSA binding data to the pharmacokinetic profiles of the investigated therapeutic agents is discussed. Structural, biological and drug binding properties of AAG as well as the applicability of the CD method in studying drug-protein binding interactions are also briefly reviewed.

  7. Design and synthesis of tag-free photoprobes for the identification of the molecular target for CCG-1423, a novel inhibitor of the Rho/MKL1/SRF signaling pathway

    Directory of Open Access Journals (Sweden)

    Jessica L. Bell

    2013-05-01

    Full Text Available CCG-1423 and related analogues represent a new class of inhibitors of Rho/MKL1/SRF-mediated gene transcription, a pathway that has been implicated in both cancer and fibrosis. The molecular target for these compounds is unknown. To facilitate its identification, a series of tag-free photoaffinity probes was designed and synthesized, each one containing a photoactivatable group and an acetylenic end group for subsequent attachment to a fluorescent tag using click chemistry. All were confirmed to maintain biological activity in a cell-based assay for inhibition of SRE-Luc expression. The functional activity of the most potent probe 24 was further confirmed in an assay for PC-3 cell migration. Photolysis of 24 in intact PC-3 cells followed by cell lysis, click ligation of a fluorescent dye, and gel electrophoresis revealed specific labeling of a single 24 kDa band that could be blocked with an active competitor. Future work will focus on identifying the labeled protein(s.

  8. New N-phenylpyrrolamide DNA gyrase B inhibitors: Optimization of efficacy and antibacterial activity.

    Science.gov (United States)

    Durcik, Martina; Lovison, Denise; Skok, Žiga; Durante Cruz, Cristina; Tammela, Päivi; Tomašič, Tihomir; Benedetto Tiz, Davide; Draskovits, Gábor; Nyerges, Ákos; Pál, Csaba; Ilaš, Janez; Peterlin Mašič, Lucija; Kikelj, Danijel; Zidar, Nace

    2018-06-25

    The ATP binding site located on the subunit B of DNA gyrase is an attractive target for the development of new antibacterial agents. In recent decades, several small-molecule inhibitor classes have been discovered but none has so far reached the market. We present here the discovery of a promising new series of N-phenylpyrrolamides with low nanomolar IC 50 values against DNA gyrase, and submicromolar IC 50 values against topoisomerase IV from Escherichia coli and Staphylococcus aureus. The most potent compound in the series has an IC 50 value of 13 nM against E. coli gyrase. Minimum inhibitory concentrations (MICs) against Gram-positive bacteria are in the low micromolar range. The oxadiazolone derivative 11a, with an IC 50 value of 85 nM against E. coli DNA gyrase displays the most potent antibacterial activity, with MIC values of 1.56 μM against Enterococcus faecalis, and 3.13 μM against wild type S. aureus, methicillin-resistant S. aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). The activity against wild type E. coli in the presence of efflux pump inhibitor phenylalanine-arginine β-naphthylamide (PAβN) is 4.6 μM. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  9. Renal function in heart transplant patients after switch to combined mammalian target of rapamycin inhibitor and calcineurin inhibitor therapy

    Directory of Open Access Journals (Sweden)

    Helmschrott M

    2017-06-01

    Full Text Available Matthias Helmschrott,1 Rasmus Rivinius,1 Thomas Bruckner,2 Hugo A Katus,1 Andreas O Doesch1 1Department of Cardiology, Angiology, Pneumology, 2Institute for Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany Background: A calcineurin inhibitor (CNI-based immunosuppression combined with mammalian target of rapamycin inhibitors (mTORs seems to be attractive in patients after heart transplantation (HTX in special clinical situations, for example, in patients with adverse drug effects of prior immunosuppression. Previous studies in patients after HTX detected advantageous effects regarding renal function of a tacrolimus (TAC-based vs cyclosporine-A (CSA-based immunosuppression (in combination with mycophenolate mofetil. However, data regarding renal function after HTX in mTOR/CNI patients remain limited. Aim: Primary end point of the present study was to analyze renal function in HTX patients 1 year after switch to an mTOR/CNI-based immunosuppression. Methods: Data of 80 HTX patients after change to mTOR/CNI-based immunosuppression were retrospectively analyzed. Renal function was assessed by measured serum creatinine and by estimated glomerular filtration rate (eGFR calculated from Modification of Diet in Renal Disease equation. Results: Twenty-nine patients received mTOR/CSA-based treatment and 51 patients received mTOR/TAC-based therapy. At time of switch and at 1-year follow-up, serum creatinine and eGFR did not differ significantly between both study groups (all P=not statistically significant. Analysis of variances with repeated measurements detected a similar change of renal function in both study groups. Conclusion: The present study detected no significant differences between both mTOR/CNI study groups, indicating a steady state of renal function in HTX patients after switch of immunosuppressive regimen. Keywords: heart transplantation, cyclosporine A, tacrolimus, risk factors

  10. Structure-based development of small molecule PFKFB3 inhibitors: a framework for potential cancer therapeutic agents targeting the Warburg effect.

    Directory of Open Access Journals (Sweden)

    Minsuh Seo

    Full Text Available Cancer cells adopt glycolysis as the major source of metabolic energy production for fast cell growth. The HIF-1-induced PFKFB3 plays a key role in this adaptation by elevating the concentration of Fru-2,6-BP, the most potent glycolysis stimulator. As this metabolic conversion has been suggested to be a hallmark of cancer, PFKFB3 has emerged as a novel target for cancer chemotherapy. Here, we report that a small molecular inhibitor, N4A, was identified as an initial lead compound for PFKFB3 inhibitor with therapeutic potential. In an attempt to improve its potency, we determined the crystal structure of the PFKFB3•N4A complex to 2.4 Å resolution and, exploiting the resulting molecular information, attained the more potent YN1. When tested on cultured cancer cells, both N4A and YN1 inhibited PFKFB3, suppressing the Fru-2,6-BP level, which in turn suppressed glycolysis and, ultimately, led to cell death. This study validates PFKFB3 as a target for new cancer therapies and provides a framework for future development efforts.

  11. Azidoblebbistatin, a photoreactive myosin inhibitor

    Science.gov (United States)

    Képiró, Miklós; Várkuti, Boglárka H.; Bodor, Andrea; Hegyi, György; Drahos, László; Kovács, Mihály; Málnási-Csizmadia, András

    2012-01-01

    Photoreactive compounds are important tools in life sciences that allow precisely timed covalent crosslinking of ligands and targets. Using a unique technique we have synthesized azidoblebbistatin, which is a derivative of blebbistatin, the most widely used myosin inhibitor. Without UV irradiation azidoblebbistatin exhibits identical inhibitory properties to those of blebbistatin. Using UV irradiation, azidoblebbistatin can be covalently crosslinked to myosin, which greatly enhances its in vitro and in vivo effectiveness. Photo-crosslinking also eliminates limitations associated with the relatively low myosin affinity and water solubility of blebbistatin. The wavelength used for photo-crosslinking is not toxic for cells and tissues, which confers a great advantage in in vivo tests. Because the crosslink results in an irreversible association of the inhibitor to myosin and the irradiation eliminates the residual activity of unbound inhibitor molecules, azidoblebbistatin has a great potential to become a highly effective tool in both structural studies of actomyosin contractility and the investigation of cellular and physiological functions of myosin II. We used azidoblebbistatin to identify previously unknown low-affinity targets of the inhibitor (EC50 ≥ 50 μM) in Dictyostelium discoideum, while the strongest interactant was found to be myosin II (EC50 = 5 μM). Our results demonstrate that azidoblebbistatin, and potentially other azidated drugs, can become highly useful tools for the identification of strong- and weak-binding cellular targets and the determination of the apparent binding affinities in in vivo conditions. PMID:22647605

  12. Structure-based lead optimization to improve antiviral potency and ADMET properties of phenyl-1H-pyrrole-carboxamide entry inhibitors targeted to HIV-1 gp120.

    Science.gov (United States)

    Curreli, Francesca; Belov, Dmitry S; Kwon, Young Do; Ramesh, Ranjith; Furimsky, Anna M; O'Loughlin, Kathleen; Byrge, Patricia C; Iyer, Lalitha V; Mirsalis, Jon C; Kurkin, Alexander V; Altieri, Andrea; Debnath, Asim K

    2018-05-12

    We are continuing our concerted effort to optimize our first lead entry antagonist, NBD-11021, which targets the Phe43 cavity of the HIV-1 envelope glycoprotein gp120, to improve antiviral potency and ADMET properties. In this report, we present a structure-based approach that helped us to generate working hypotheses to modify further a recently reported advanced lead entry antagonist, NBD-14107, which showed significant improvement in antiviral potency when tested in a single-cycle assay against a large panel of Env-pseudotyped viruses. We report here the synthesis of twenty-nine new compounds and evaluation of their antiviral activity in a single-cycle and multi-cycle assay to derive a comprehensive structure-activity relationship (SAR). We have selected three inhibitors with the high selectivity index for testing against a large panel of 55 Env-pseudotyped viruses representing a diverse set of clinical isolates of different subtypes. The antiviral activity of one of these potent inhibitors, 55 (NBD-14189), against some clinical isolates was as low as 63 nM. We determined the sensitivity of CD4-binding site mutated-pseudoviruses to these inhibitors to confirm that they target HIV-1 gp120. Furthermore, we assessed their ADMET properties and compared them to the clinical candidate attachment inhibitor, BMS-626529. The ADMET data indicate that some of these new inhibitors have comparable ADMET properties to BMS-626529 and can be optimized further to potential clinical candidates. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  13. Ebselen and analogs as inhibitors of Bacillus anthracis thioredoxin reductase and bactericidal antibacterials targeting Bacillus species, Staphylococcus aureus and Mycobacterium tuberculosis.

    Science.gov (United States)

    Gustafsson, Tomas N; Osman, Harer; Werngren, Jim; Hoffner, Sven; Engman, Lars; Holmgren, Arne

    2016-06-01

    Bacillus anthracis is the causative agent of anthrax, a disease associated with a very high mortality rate in its invasive forms. We studied a number of ebselen analogs as inhibitors of B. anthracis thioredoxin reductase and their antibacterial activity on Bacillus subtilis, Staphylococcus aureus, Bacillus cereus and Mycobacterium tuberculosis. The most potent compounds in the series gave IC(50) values down to 70 nM for the pure enzyme and minimal inhibitory concentrations (MICs) down to 0.4 μM (0.12 μg/ml) for B. subtilis, 1.5 μM (0.64 μg/ml) for S. aureus, 2 μM (0.86 μg/ml) for B. cereus and 10 μg/ml for M. tuberculosis. Minimal bactericidal concentrations (MBCs) were found at 1-1.5 times the MIC, indicating a general, class-dependent, bactericidal mode of action. The combined bacteriological and enzymological data were used to construct a preliminary structure-activity-relationship for the benzoisoselenazol class of compounds. When S. aureus and B. subtilis were exposed to ebselen, we were unable to isolate resistant mutants on both solid and in liquid medium suggesting a high resistance barrier. These results suggest that ebselen and analogs thereof could be developed into a novel antibiotic class, useful for the treatment of infections caused by B. anthracis, S. aureus, M. tuberculosis and other clinically important bacteria. Furthermore, the high barrier against resistance development is encouraging for further drug development. We have characterized the thioredoxin system from B. anthracis as a novel drug target and ebselen and analogs thereof as a potential new class of antibiotics targeting several important human pathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Histone deacetylase (HDAC) inhibitors targeting HDAC3 and HDAC1 ameliorate polyglutamine-elicited phenotypes in model systems of Huntington's disease

    Science.gov (United States)

    Jia, Haiqun; Pallos, Judit; Jacques, Vincent; Lau, Alice; Tang, Bin; Cooper, Andrew; Syed, Adeela; Purcell, Judith; Chen, Yi; Sharma, Shefali; Sangrey, Gavin R.; Darnell, Shayna B.; Plasterer, Heather; Sadri-Vakili, Ghazaleh; Gottesfeld, Joel M.; Thompson, Leslie M.; Rusche, James R.; Marsh, J. Lawrence; Thomas, Elizabeth A.

    2012-01-01

    We have previously demonstrated amelioration of Huntington's disease (HD)-related phenotypes in R6/2 transgenic mice in response to treatment with the novel histone deacetylase (HDAC) inhibitor 4b. Here we have measured the selectivity profiles of 4b and related compounds against class I and class II HDACs and have tested their ability to restore altered expression of genes related to HD pathology in mice and to rescue disease effects in cell culture and Drosophila models of HD. R6/2 transgenic and wild-type (wt) mice received daily injections of HDAC inhibitors for 3 days followed by real-time PCR analysis to detect expression differences for 13 HD-related genes. We find that HDACi 4b and 136, two compounds showing high potency for inhibiting HDAC3 were most effective in reversing the expression of genes relevant to HD, including Ppp1r1b, which encodes DARPP-32, a marker for medium spiny striatal neurons. In contrast, compounds targeting HDAC1 were less effective at correcting gene expression abnormalities in R6/2 transgenic mice, but did cause significant increases in the expression of selected genes. An additional panel of 4b-related compounds was tested in a Drosophila model of HD and in STHdhQ111 striatal cells to further distinguish HDAC selectivity. Significant improvement in huntingtin-elicited Drosophila eye neurodegeneration in the fly was observed in response to treatment with compounds targeting human HDAC1 and/or HDAC3. In STHdhQ111 striatal cells, the ability of HDAC inhibitors to improve Htt-elicited metabolic deficits correlated with the potency at inhibiting HDAC1 and HDAC3, although the IC50 values for HDAC1 inhibition were typically 10-fold higher than for inhibition of HDAC3. Assessment of HDAC protein localization in brain tissue by Western blot analysis revealed accumulation of HDAC1 and HDAC3 in the nucleus of HD transgenic mice compared to wt mice, with a concurrent decrease in cytoplasmic localization, suggesting that these HDACs contribute

  15. A survey of cyclic replacements for the central diamide moiety of inhibitors of inosine monophosphate dehydrogenase.

    Science.gov (United States)

    Dhar, T G Murali; Liu, Chunjian; Pitts, William J; Guo, Junquing; Watterson, Scott H; Gu, Henry; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Barrish, Joel C; Hollenbaugh, Diane; Iwanowicz, Edwin J

    2002-11-04

    A series of heterocyclic replacements for the central diamide moiety of 1, a potent small molecule inhibitor of inosine monophosphate dehydrogenase (IMPDH) were explored The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for these new series of inhibitors is given.

  16. Fasxiator, a novel factor XIa inhibitor from snake venom, and its site-specific mutagenesis to improve potency and selectivity.

    Science.gov (United States)

    Chen, W; Carvalho, L P D; Chan, M Y; Kini, R M; Kang, T S

    2015-02-01

    Bleeding remains a major limitation of standard anticoagulant drugs that target the extrinsic and common coagulation pathways. Recently, intrinsic coagulation factors are increasingly being investigated as alternative targets for developing anticoagulant drugs with lower bleeding risk. Goals were to (i) identify novel anticoagulants selectively targeting intrinsic coagulation pathway and (ii) characterize and further improve the properties of the identified anticoagulants. We have isolated and sequenced a specific factor XIa (FXIa) inhibitor, henceforth named Fasxiator, from the venom of the banded krait snake, Bungarus fasciatus. It is a Kunitz-type protease inhibitor that prolonged activated partial thromboplastin time without significant effects on prothrombin time. Fasxiator was recombinantly expressed (rFasxiator), purified, and characterized to be a slow-type inhibitor of FXIa that exerts its anticoagulant activities (doubled activated partial thromboplastin time at ~ 3 μmol L(-1) ) by selectively inhibiting human FXIa in in vitro assays. A series of mutants were subsequently generated to improve the potency and selectivity of recombinant rFasxiator. rFasxiatorN17R,L19E showed the best balance between potency (IC50 ~ 1 nmol L(-1) ) and selectivity (> 100 times). rFasxiatorN17R,L19E is a competitive slow-type inhibitor of FXIa (Ki  = 0.86 nmol L(-1) ), possesses anticoagulant activity that is ~ 10 times stronger in human plasma than in murine plasma, and prolonged the occlusion time of mice carotid artery in FeCl3 -induced thrombosis models. We have isolated an exogenous FXIa specific inhibitor, engineered it to improve its potency by ~ 1000 times and demonstrated its in vitro and in vivo efficacy. These proof-of-principle data supported the further development of Fasxiator as a novel anticoagulant candidate. © 2014 International Society on Thrombosis and Haemostasis.

  17. Furan-2-ylmethylene thiazolidinediones as novel, potent, and selective inhibitors of phosphoinositide 3-kinase gamma.

    Science.gov (United States)

    Pomel, Vincent; Klicic, Jasna; Covini, David; Church, Dennis D; Shaw, Jeffrey P; Roulin, Karen; Burgat-Charvillon, Fabienne; Valognes, Delphine; Camps, Montserrat; Chabert, Christian; Gillieron, Corinne; Françon, Bernard; Perrin, Dominique; Leroy, Didier; Gretener, Denise; Nichols, Anthony; Vitte, Pierre Alain; Carboni, Susanna; Rommel, Christian; Schwarz, Matthias K; Rückle, Thomas

    2006-06-29

    Class I phosphoinositide 3-kinases (PI3Ks), in particular PI3Kgamma, have become attractive drug targets for inflammatory and autoimmune diseases. Here, we disclose a novel series of furan-2-ylmethylene thiazolidinediones as selective, ATP-competitive PI3Kgamma inhibitors. Structure-based design and X-ray crystallography of complexes formed by inhibitors bound to PI3Kgamma identified key pharmacophore features for potency and selectivity. An acidic NH group on the thiazolidinedione moiety and a hydroxy group on the furan-2-yl-phenyl part of the molecule play crucial roles in binding to PI3K and contribute to class IB PI3K selectivity. Compound 26 (AS-252424), a potent and selective small-molecule PI3Kgamma inhibitor emerging from these efforts, was further profiled in three different cellular PI3K assays and shown to be selective for class IB PI3K-mediated cellular effects. Oral administration of 26 in a mouse model of acute peritonitis led to a significant reduction of leukocyte recruitment.

  18. PKI-179: an orally efficacious dual phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) inhibitor.

    Science.gov (United States)

    Venkatesan, Aranapakam M; Chen, Zecheng; dos Santos, Osvaldo; Dehnhardt, Christoph; Santos, Efren Delos; Ayral-Kaloustian, Semiramis; Mallon, Robert; Hollander, Irwin; Feldberg, Larry; Lucas, Judy; Yu, Ker; Chaudhary, Inder; Mansour, Tarek S

    2010-10-01

    A series of mono-morpholino 1,3,5-triazine derivatives (8a-8q) bearing a 3-oxa-8-azabicyclo[3.2.1]octane were prepared and evaluated for PI3-kinase/mTOR activity. Replacement of one of the bis-morpholines in lead compound 1 (PKI-587) with 3-oxa-8-azabicyclo[3.2.1]octane and reduction of the molecular weight yielded 8m (PKI-179), an orally efficacious dual PI3-kinase/mTOR inhibitor. The in vitro activity, in vivo efficacy, and PK properties of 8m are discussed. Copyright © 2010. Published by Elsevier Ltd.

  19. Second-Generation Non-Covalent NAAA Inhibitors are Protective in a Model of Multiple Sclerosis.

    Science.gov (United States)

    Migliore, Marco; Pontis, Silvia; Fuentes de Arriba, Angel Luis; Realini, Natalia; Torrente, Esther; Armirotti, Andrea; Romeo, Elisa; Di Martino, Simona; Russo, Debora; Pizzirani, Daniela; Summa, Maria; Lanfranco, Massimiliano; Ottonello, Giuliana; Busquet, Perrine; Jung, Kwang-Mook; Garcia-Guzman, Miguel; Heim, Roger; Scarpelli, Rita; Piomelli, Daniele

    2016-09-05

    Palmitoylethanolamide (PEA) and oleoylethanolamide (OEA) are endogenous lipid mediators that suppress inflammation. Their actions are terminated by the intracellular cysteine amidase, N-acylethanolamine acid amidase (NAAA). Even though NAAA may offer a new target for anti-inflammatory therapy, the lipid-like structures and reactive warheads of current NAAA inhibitors limit the use of these agents as oral drugs. A series of novel benzothiazole-piperazine derivatives that inhibit NAAA in a potent and selective manner by a non-covalent mechanism are described. A prototype member of this class (8) displays high oral bioavailability, access to the central nervous system (CNS), and strong activity in a mouse model of multiple sclerosis (MS). This compound exemplifies a second generation of non-covalent NAAA inhibitors that may be useful in the treatment of MS and other chronic CNS disorders. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Synthesis and biological evaluation of novel thiadiazole amides as potent Cdc25B and PTP1B inhibitors.

    Science.gov (United States)

    Li, Yingjun; Yu, Yang; Jin, Kun; Gao, Lixin; Luo, Tongchuan; Sheng, Li; Shao, Xin; Li, Jia

    2014-09-01

    A series of novel thiadiazole amide derivatives have been synthesized and evaluated for inhibitory activities against Cdc25B and PTP1B. Most of them showed inhibitory activities against Cdc25B (IC50=1.18-8.01 μg/mL) and PTP1B (IC50=0.85-8.75 μg/mL), respectively. Moreover, compounds 5b and 4l were most potent with IC50 values of 1.18 and 0.85 μg/mL for Cdc25B and PTP1B, respectively, compared with reference drugs Na3VO4 (IC50=0.93 μg/mL) and oleanolic acid (IC50=0.85 μg/mL). The results of selectivity experiments showed that the target compounds were selective inhibitors against PTP1B and Cdc25B. Enzyme kinetic experiments demonstrated that compound 5k was a specific inhibitor with the typical characteristics of a mixed inhibitor. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Structure-Based Design of an Iminoheterocyclic β-Site Amyloid Precursor Protein Cleaving Enzyme (BACE) Inhibitor that Lowers Central Aβ in Nonhuman Primates

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Mihirbaran; Wu, Yusheng; Misiaszek, Jeffrey; Li, Guoqing; Buevich, Alexei; Caldwell, John P.; Liu, Xiaoxiang; Mazzola, Robert D.; Orth, Peter; Strickland, Corey; Voigt, Johannes; Wang, Hongwu; Zhu, Zhaoning; Chen, Xia; Grzelak, Michael; Hyde, Lynn A.; Kuvelkar, Reshma; Leach, Prescott T.; Terracina, Giuseppe; Zhang, Lili; Zhang, Qi; Michener, Maria S.; Smith, Brad; Cox, Kathleen; Grotz, Diane; Favreau, Leonard; Mitra, Kaushik; Kazakevich, Irina; McKittrick, Brian A.; Greenlee, William; Kennedy, Matthew E.; Parker, Eric M.; Cumming, Jared N.; Stamford, Andrew W. (Merck)

    2016-04-14

    We describe successful efforts to optimize the in vivo profile and address off-target liabilities of a series of BACE1 inhibitors represented by 6 that embodies the recently validated fused pyrrolidine iminopyrimidinone scaffold. Employing structure-based design, truncation of the cyanophenyl group of 6 that binds in the S3 pocket of BACE1 followed by modification of the thienyl group in S1 was pursued. Optimization of the pyrimidine substituent that binds in the S2'–S2'' pocket of BACE1 remediated time-dependent CYP3A4 inhibition of earlier analogues in this series and imparted high BACE1 affinity. These efforts resulted in the discovery of difluorophenyl analogue 9 (MBi-4), which robustly lowered CSF and cortex Aβ40 in both rats and cynomolgus monkeys following a single oral dose. Compound 9 represents a unique molecular shape among BACE inhibitors reported to potently lower central Aβ in nonrodent preclinical species.

  2. The pan phosphoinositide 3-kinase/mammalian target of rapamycin inhibitor SAR245409 (voxtalisib/XL765) blocks survival, adhesion and proliferation of primary chronic lymphocytic leukemia cells.

    Science.gov (United States)

    Thijssen, R; Ter Burg, J; van Bochove, G G W; de Rooij, M F M; Kuil, A; Jansen, M H; Kuijpers, T W; Baars, J W; Virone-Oddos, A; Spaargaren, M; Egile, C; van Oers, M H J; Eldering, E; Kersten, M J; Kater, A P

    2016-02-01

    The phosphoinositide 3-kinases (PI3Ks) are critical components of the B-cell receptor (BCR) pathway and have an important role in the pathobiology of chronic lymphocytic leukemia (CLL). Inhibitors of PI3Kδ block BCR-mediated cross-talk between CLL cells and the lymph node microenvironment and provide significant clinical benefit to CLL patients. However, the PI3Kδ inhibitors applied thus far have limited direct impact on leukemia cell survival and thus are unlikely to eradicate the disease. The use of inhibitors of multiple isoforms of PI3K might lead to deeper remissions. Here we demonstrate that the pan-PI3K/mammalian target of rapamycin inhibitor SAR245409 (voxtalisib/XL765) was more pro-apoptotic to CLL cells--irrespective of their ATM/p53 status--than PI3Kα or PI3Kδ isoform selective inhibitors. Furthermore, SAR245409 blocked CLL survival, adhesion and proliferation. Moreover, SAR245409 was a more potent inhibitor of T-cell-mediated production of cytokines, which support CLL survival. Taken together, our in vitro data provide a rationale for the evaluation of a pan-PI3K inhibitor in CLL patients.

  3. Small-molecule kinase inhibitors: an analysis of FDA-approved drugs

    DEFF Research Database (Denmark)

    Wu, Peng; Nielsen, Thomas Eiland; Clausen, Mads Hartvig

    2016-01-01

    Small-molecule kinase inhibitors (SMKIs), 28 of which are approved by the US Food and Drug Administration (FDA), have been actively pursued as promising targeted therapeutics. Here, we assess the key structural and physicochemical properties, target selectivity and mechanism of function, and ther......Small-molecule kinase inhibitors (SMKIs), 28 of which are approved by the US Food and Drug Administration (FDA), have been actively pursued as promising targeted therapeutics. Here, we assess the key structural and physicochemical properties, target selectivity and mechanism of function...

  4. Integrins as Therapeutic Targets: Successes and Cancers

    Directory of Open Access Journals (Sweden)

    Sabine Raab-Westphal

    2017-08-01

    Full Text Available Integrins are transmembrane receptors that are central to the biology of many human pathologies. Classically mediating cell-extracellular matrix and cell-cell interaction, and with an emerging role as local activators of TGFβ, they influence cancer, fibrosis, thrombosis and inflammation. Their ligand binding and some regulatory sites are extracellular and sensitive to pharmacological intervention, as proven by the clinical success of seven drugs targeting them. The six drugs on the market in 2016 generated revenues of some US$3.5 billion, mainly from inhibitors of α4-series integrins. In this review we examine the current developments in integrin therapeutics, especially in cancer, and comment on the health economic implications of these developments.

  5. Biaryls as potent, tunable dual neurokinin 1 receptor antagonists and serotonin transporter inhibitors.

    Science.gov (United States)

    Degnan, Andrew P; Tora, George O; Han, Ying; Rajamani, Ramkumar; Bertekap, Robert; Krause, Rudolph; Davis, Carl D; Hu, Joanna; Morgan, Daniel; Taylor, Sarah J; Krause, Kelly; Li, Yu-Wen; Mattson, Gail; Cunningham, Melissa A; Taber, Matthew T; Lodge, Nicholas J; Bronson, Joanne J; Gillman, Kevin W; Macor, John E

    2015-08-01

    Depression is a serious illness that affects millions of patients. Current treatments are associated with a number of undesirable side effects. Neurokinin 1 receptor (NK1R) antagonists have recently been shown to potentiate the antidepressant effects of serotonin-selective reuptake inhibitors (SSRIs) in a number of animal models. Herein we describe the optimization of a biaryl chemotype to provide a series of potent dual NK1R antagonists/serotonin transporter (SERT) inhibitors. Through the choice of appropriate substituents, the SERT/NK1R ratio could be tuned to afford a range of target selectivity profiles. This effort culminated in the identification of an analog that demonstrated oral bioavailability, favorable brain uptake, and efficacy in the gerbil foot tap model. Ex vivo occupancy studies with compound 58 demonstrated the ability to maintain NK1 receptor saturation (>88% occupancy) while titrating the desired level of SERT occupancy (11-84%) via dose selection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Identification of novel and potent isoquinoline aminooxazole-based IMPDH inhibitors.

    Science.gov (United States)

    Chen, Ping; Norris, Derek; Haslow, Kristin D; Murali Dhar, T G; Pitts, William J; Watterson, Scott H; Cheney, Daniel L; Bassolino, Donna A; Fleener, Catherine A; Rouleau, Katherine A; Hollenbaugh, Diane L; Townsend, Robert M; Barrish, Joel C; Iwanowicz, Edwin J

    2003-04-07

    Screening of our in-house compound collection led to the discovery of 5-bromo-6-amino-2-isoquinoline 1 as a weak inhibitor of IMPDH. Subsequent optimization of 1 afforded a series of novel 2-isoquinolinoaminooxazole-based inhibitors, represented by 17, with single-digit nanomolar potency against the enzyme.

  7. Targeting tumor-initiating cells: Eliminating anabolic cancer stem cells with inhibitors of protein synthesis or by mimicking caloric restriction

    Science.gov (United States)

    Lamb, Rebecca; Harrison, Hannah; Smith, Duncan L.; Townsend, Paul A.; Jackson, Thomas; Ozsvari, Bela; Martinez-Outschoorn, Ubaldo E.; Pestell, Richard G.; Howell, Anthony; Lisanti, Michael P.; Sotgia, Federica

    2015-01-01

    We have used an unbiased proteomic profiling strategy to identify new potential therapeutic targets in tumor-initiating cells (TICs), a.k.a., cancer stem cells (CSCs). Towards this end, the proteomes of mammospheres from two breast cancer cell lines were directly compared to attached monolayer cells. This allowed us to identify proteins that were highly over-expressed in CSCs and/or progenitor cells. We focused on ribosomal proteins and protein folding chaperones, since they were markedly over-expressed in mammospheres. Overall, we identified >80 molecules specifically associated with protein synthesis that were commonly upregulated in mammospheres. Most of these proteins were also transcriptionally upregulated in human breast cancer cells in vivo, providing evidence for their potential clinical relevance. As such, increased mRNA translation could provide a novel mechanism for enhancing the proliferative clonal expansion of TICs. The proteomic findings were functionally validated using known inhibitors of protein synthesis, via three independent approaches. For example, puromycin (which mimics the structure of tRNAs and competitively inhibits protein synthesis) preferentially targeted CSCs in both mammospheres and monolayer cultures, and was ~10-fold more potent for eradicating TICs, than “bulk” cancer cells. In addition, rapamycin, which inhibits mTOR and hence protein synthesis, was very effective at reducing mammosphere formation, at nanomolar concentrations. Finally, mammosphere formation was also markedly inhibited by methionine restriction, which mimics the positive effects of caloric restriction in cultured cells. Remarkably, mammosphere formation was >18-fold more sensitive to methionine restriction and replacement, as directly compared to monolayer cell proliferation. Methionine is absolutely required for protein synthesis, since every protein sequence starts with a methionine residue. Thus, the proliferation and survival of CSCs is very sensitive to

  8. Activity of dual SRC-ABL inhibitors highlights the role of BCR/ABL kinase dynamics in drug resistance

    Science.gov (United States)

    Azam, Mohammad; Nardi, Valentina; Shakespeare, William C.; Metcalf, Chester A.; Bohacek, Regine S.; Wang, Yihan; Sundaramoorthi, Raji; Sliz, Piotr; Veach, Darren R.; Bornmann, William G.; Clarkson, Bayard; Dalgarno, David C.; Sawyer, Tomi K.; Daley, George Q.

    2006-01-01

    Mutation in the ABL kinase domain is the principal mechanism of imatinib resistance in patients with chronic myelogenous leukemia. Many mutations favor active kinase conformations that preclude imatinib binding. Because the active forms of ABL and SRC resemble one another, we tested two dual SRC-ABL kinase inhibitors, AP23464 and PD166326, against 58 imatinib-resistant (IMR) BCR/ABL kinase variants. Both compounds potently inhibit most IMR variants, and in vitro drug selection demonstrates that active (AP23464) and open (PD166326) conformation-specific compounds are less susceptible to resistance than imatinib. Combinations of inhibitors suppressed essentially all resistance mutations, with the notable exception of T315I. Guided by mutagenesis studies and molecular modeling, we designed a series of AP23464 analogues to target T315I. The analogue AP23846 inhibited both native and T315I variants of BCR/ABL with submicromolar potency but showed nonspecific cellular toxicity. Our data illustrate how conformational dynamics of the ABL kinase accounts for the activity of dual SRC-ABL inhibitors against IMR-mutants and provides a rationale for combining conformation specific inhibitors to suppress resistance. PMID:16754879

  9. Targeting RNA transcription and translation in ovarian cancer cells with pharmacological inhibitor CDKI-73.

    Science.gov (United States)

    Lam, Frankie; Abbas, Abdullahi Y; Shao, Hao; Teo, Theodosia; Adams, Julian; Li, Peng; Bradshaw, Tracey D; Fischer, Peter M; Walsby, Elisabeth; Pepper, Chris; Chen, Yi; Ding, Jian; Wang, Shudong

    2014-09-15

    Dysregulation of cellular transcription and translation is a fundamental hallmark of cancer. As CDK9 and Mnks play pivotal roles in the regulation of RNA transcription and protein synthesis, respectively, they are important targets for drug development. We herein report the cellular mechanism of a novel CDK9 inhibitor CDKI-73 in an ovarian cancer cell line (A2780). We also used shRNA-mediated CDK9 knockdown to investigate the importance of CDK9 in the maintenance of A2780 cells. This study revealed that CDKI-73 rapidly inhibited cellular CDK9 kinase activity and down-regulated the RNAPII phosphorylation. This subsequently caused a decrease in the eIF4E phosphorylation by blocking Mnk1 kinase activity. Consistently, CDK9 shRNA was also found to down-regulate the Mnk1 expression. Both CDKI-73 and CDK9 shRNA decreased anti-apoptotic proteins Mcl-1 and Bcl-2 and induced apoptosis. The study confirmed that CDK9 is required for cell survival and that ovarian cancer may be susceptible to CDK9 inhibition strategy. The data also implied a role of CDK9 in eIF4E-mediated translational control, suggesting that CDK9 may have important implication in the Mnk-eIF4E axis, the key determinants of PI3K/Akt/mTOR- and Ras/Raf/MAPK-mediated tumorigenic activity. As such, CDK9 inhibitor drug candidate CDKI-73 should have a major impact on these pathways in human cancers.

  10. Model Based Targeting of IL-6-Induced Inflammatory Responses in Cultured Primary Hepatocytes to Improve Application of the JAK Inhibitor Ruxolitinib.

    Science.gov (United States)

    Sobotta, Svantje; Raue, Andreas; Huang, Xiaoyun; Vanlier, Joep; Jünger, Anja; Bohl, Sebastian; Albrecht, Ute; Hahnel, Maximilian J; Wolf, Stephanie; Mueller, Nikola S; D'Alessandro, Lorenza A; Mueller-Bohl, Stephanie; Boehm, Martin E; Lucarelli, Philippe; Bonefas, Sandra; Damm, Georg; Seehofer, Daniel; Lehmann, Wolf D; Rose-John, Stefan; van der Hoeven, Frank; Gretz, Norbert; Theis, Fabian J; Ehlting, Christian; Bode, Johannes G; Timmer, Jens; Schilling, Marcel; Klingmüller, Ursula

    2017-01-01

    IL-6 is a central mediator of the immediate induction of hepatic acute phase proteins (APP) in the liver during infection and after injury, but increased IL-6 activity has been associated with multiple pathological conditions. In hepatocytes, IL-6 activates JAK1-STAT3 signaling that induces the negative feedback regulator SOCS3 and expression of APPs. While different inhibitors of IL-6-induced JAK1-STAT3-signaling have been developed, understanding their precise impact on signaling dynamics requires a systems biology approach. Here we present a mathematical model of IL-6-induced JAK1-STAT3 signaling that quantitatively links physiological IL-6 concentrations to the dynamics of IL-6-induced signal transduction and expression of target genes in hepatocytes. The mathematical model consists of coupled ordinary differential equations (ODE) and the model parameters were estimated by a maximum likelihood approach, whereas identifiability of the dynamic model parameters was ensured by the Profile Likelihood. Using model simulations coupled with experimental validation we could optimize the long-term impact of the JAK-inhibitor Ruxolitinib, a therapeutic compound that is quickly metabolized. Model-predicted doses and timing of treatments helps to improve the reduction of inflammatory APP gene expression in primary mouse hepatocytes close to levels observed during regenerative conditions. The concept of improved efficacy of the inhibitor through multiple treatments at optimized time intervals was confirmed in primary human hepatocytes. Thus, combining quantitative data generation with mathematical modeling suggests that repetitive treatment with Ruxolitinib is required to effectively target excessive inflammatory responses without exceeding doses recommended by the clinical guidelines.

  11. Discovery and quantitative structure-activity relationship study of lepidopteran HMG-CoA reductase inhibitors as selective insecticides.

    Science.gov (United States)

    Zang, Yang-Yang; Li, Yuan-Mei; Yin, Yue; Chen, Shan-Shan; Kai, Zhen-Peng

    2017-09-01

    In a previous study we have demonstrated that insect 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) can be a potential selective insecticide target. Three series of inhibitors were designed on the basis of the difference in HMGR structures from Homo sapiens and Manduca sexta, with the aim of discovering potent selective insecticide candidates. An in vitro bioassay showed that gem-difluoromethylenated statin analogues have potent effects on JH biosynthesis of M. sexta and high selectivity between H. sapiens and M. sexta. All series II compounds {1,3,5-trisubstituted [4-tert-butyl 2-(5,5-difluoro-2,2-dimethyl-6-vinyl-4-yl) acetate] pyrazoles} have some effect on JH biosynthesis, whereas most of them are inactive on human HMGR. In particular, the IC 50 value of compound II-12 (37.8 nm) is lower than that of lovastatin (99.5 nm) and similar to that of rosuvastatin (24.2 nm). An in vivo bioassay showed that I-1, I-2, I-3 and II-12 are potential selective insecticides, especially for lepidopteran pest control. A predictable and statistically meaningful CoMFA model of 23 inhibitors (20 as training sets and three as test sets) was obtained with a value of q 2 and r 2 of 0.66 and 0.996 respectively. The final model suggested that a potent insect HMGR inhibitor should contain suitable small and non-electronegative groups in the ring part, and electronegative groups in the side chain. Four analogues were discovered as potent selective lepidopteran HMGR inhibitors, which can specifically be used for lepidopteran pest control. The CoMFA model will be useful for the design of new selective insect HMGR inhibitors that are structurally related to the training set compounds. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  12. mTOR inhibitors alone and in combination with JAK2 inhibitors effectively inhibit cells of myeloproliferative neoplasms.

    Directory of Open Access Journals (Sweden)

    Costanza Bogani

    Full Text Available BACKGROUND: Dysregulated signaling of the JAK/STAT pathway is a common feature of chronic myeloproliferative neoplasms (MPN, usually associated with JAK2V617F mutation. Recent clinical trials with JAK2 inhibitors showed significant improvements in splenomegaly and constitutional symptoms in patients with myelofibrosis but meaningful molecular responses were not documented. Accordingly, there remains a need for exploring new treatment strategies of MPN. A potential additional target for treatment is represented by the PI3K/AKT/mammalian target of rapamycin (mTOR pathway that has been found constitutively activated in MPN cells; proof-of-evidence of efficacy of the mTOR inhibitor RAD001 has been obtained recently in a Phase I/II trial in patients with myelofibrosis. The aim of the study was to characterize the effects in vitro of mTOR inhibitors, used alone and in combination with JAK2 inhibitors, against MPN cells. FINDINGS: Mouse and human JAK2V617F mutated cell lines and primary hematopoietic progenitors from MPN patients were challenged with an allosteric (RAD001 and an ATP-competitive (PP242 mTOR inhibitor and two JAK2 inhibitors (AZD1480 and ruxolitinib. mTOR inhibitors effectively reduced proliferation and colony formation of cell lines through a slowed cell division mediated by changes in cell cycle transition to the S-phase. mTOR inhibitors also impaired the proliferation and prevented colony formation from MPN hematopoietic progenitors at doses significantly lower than healthy controls. JAK2 inhibitors produced similar antiproliferative effects in MPN cell lines and primary cells but were more potent inducers of apoptosis, as also supported by differential effects on cyclinD1, PIM1 and BcLxL expression levels. Co-treatment of mTOR inhibitor with JAK2 inhibitor resulted in synergistic activity against the proliferation of JAK2V617F mutated cell lines and significantly reduced erythropoietin-independent colony growth in patients with

  13. Quinolinic Carboxylic Acid Derivatives as Potential Multi-target Compounds for Neurodegeneration: Monoamine Oxidase and Cholinesterase Inhibition.

    Science.gov (United States)

    Khan, Nehal A; Khan, Imtiaz; Abid, Syed M A; Zaib, Sumera; Ibrar, Aliya; Andleeb, Hina; Hameed, Shahid; Iqbal, Jamshed

    2018-01-01

    Parkinson's disease (PD), a debilitating and progressive disorder, is among the most challenging and devastating neurodegenerative diseases predominantly affecting the people over 60 years of age. To confront PD, an advanced and operational strategy is to design single chemical functionality able to control more than one target instantaneously. In this endeavor, for the exploration of new and efficient inhibitors of Parkinson's disease, we synthesized a series of quinoline carboxylic acids (3a-j) and evaluated their in vitro monoamine oxidase and cholinesterase inhibitory activities. The molecular docking and in silico studies of the most potent inhibitors were performed to identify the probable binding modes in the active site of the monoamine oxidase enzymes. Moreover, molecular properties were calculated to evaluate the druglikeness of the compounds. The biological evaluation results revealed that the tested compounds were highly potent against monoamine oxidase (A & B), 3c targeted both the isoforms of MAO with IC50 values of 0.51 ± 0.12 and 0.51 ± 0.03 µM, respectively. The tested compounds also demonstrated high and completely selective inhibitory action against acetylcholinesterase (AChE) with IC50 values ranging from 4.36 to 89.24 µM. Among the examined derivatives, 3i was recognized as the most potent inhibitor of AChE with an IC50 value of 4.36 ± 0.12 ±µM. The compounds appear to be promising inhibitors and could be used for the future development of drugs targeting neurodegenerative disorders. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  14. Fragment-based discovery of novel pentacyclic triterpenoid derivatives as cholesteryl ester transfer protein inhibitors.

    Science.gov (United States)

    Chang, Yongzhi; Zhou, Shuxi; Li, Enqin; Zhao, Wenfeng; Ji, Yanpeng; Wen, Xiaoan; Sun, Hongbin; Yuan, Haoliang

    2017-01-27

    Cholesteryl Ester Transfer Protein (CETP) is an important therapeutic target for the treatment of atherosclerotic cardiovascular disease. Our molecular modeling study revealed that pentacyclic triterpenoid compounds could mimic the protein-ligand interactions of the endogenous ligand cholesteryl ester (CE) by occupying its binding site. Alignment of the docking conformations of oleanolic acid (OA), ursolic acid (UA) and the crystal conformations of known CETP inhibitor Torcetrapib in the active site proposed the applicability of fragment-based drug design (FBDD) approaches in this study. Accordingly, a series of pentacyclic triterpenoid derivatives have been designed and synthesized as novel CETP inhibitors. The most potent compound 12e (IC 50 :0.28 μM) validated our strategy for molecular design. Molecular dynamics simulations illustrated that the more stable hydrogen bond interaction of the UA derivative 12e with Ser191 and stronger hydrophobic interactions with Val198, Phe463 than those of OA derivative 12b mainly led to their significantly different CETP inhibitory activity. These novel potent CETP inhibitors based on ursane-type scaffold should deserve further investigation. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  15. Virtual screening of the inhibitors targeting at the viral protein 40 of Ebola virus.

    Science.gov (United States)

    Karthick, V; Nagasundaram, N; Doss, C George Priya; Chakraborty, Chiranjib; Siva, R; Lu, Aiping; Zhang, Ge; Zhu, Hailong

    2016-02-17

    The Ebola virus is highly pathogenic and destructive to humans and other primates. The Ebola virus encodes viral protein 40 (VP40), which is highly expressed and regulates the assembly and release of viral particles in the host cell. Because VP40 plays a prominent role in the life cycle of the Ebola virus, it is considered as a key target for antiviral treatment. However, there is currently no FDA-approved drug for treating Ebola virus infection, resulting in an urgent need to develop effective antiviral inhibitors that display good safety profiles in a short duration. This study aimed to screen the effective lead candidate against Ebola infection. First, the lead molecules were filtered based on the docking score. Second, Lipinski rule of five and the other drug likeliness properties are predicted to assess the safety profile of the lead candidates. Finally, molecular dynamics simulations was performed to validate the lead compound. Our results revealed that emodin-8-beta-D-glucoside from the Traditional Chinese Medicine Database (TCMD) represents an active lead candidate that targets the Ebola virus by inhibiting the activity of VP40, and displays good pharmacokinetic properties. This report will considerably assist in the development of the competitive and robust antiviral agents against Ebola infection.

  16. Inhibitors of the bacterial cell wall biosynthesis enzyme MurC.

    Science.gov (United States)

    Reck, F; Marmor, S; Fisher, S; Wuonola, M A

    2001-06-04

    A series of phosphinate transition-state analogues of the L-alanine adding enzyme (MurC) of bacterial peptidoglycan biosynthesis was prepared and tested as inhibitors of the Escherichia coli enzyme. Compound 4 was identified as a potent inhibitor of MurC from Escherichia coli with an IC(50) of 49nM.

  17. Results of the examinations of the W7-X pre-series target elements

    International Nuclear Information System (INIS)

    Boscary, J.; Boeswirth, B.; Greuner, H.; Streibl, B.; Missirlian, M.; Schlosser, J.; Schedler, B.; Scheiber, K.

    2006-01-01

    The highly heat-loaded area of the target plates of the WENDELSTEIN 7-X (W7-X) divertor is formed by 890 water-cooled target elements (TEs). This surface is designed to sustain a maximum stationary heat flux of 10 MW/m 2 and to remove a maximum power of 100 kW per element. Flat tiles made of CFC Sepcarb(r) NB31 are bonded to a CuCrZr heat sink. This joint is manufactured in two stages. In the first step, an OFHC copper interlayer is cast onto the tile by active metal casting (AMC(r)). At this stage, the joint copper-CFC is inspected by X-ray and lock-in thermography. In the second step, the AMC(r)-NB31 tiles are joined to CuCrZr. Two technologies have been investigated: electron beam welding (EBW) and hot isostatic pressing (HIP). The joint copper-CuCrZr is examined by ultrasonic method. At the end of the fabrication, the bond between the heat sink and the CFC tiles is inspected by thermography methods. The produced CFC NB31 material for W7-X showed a large scatter in the tensile strength in the ex-pitch direction in the range of 50 - 110 MPa. Pre-series TEs have been manufactured to qualify the design, the fabrication, the relevant non-destructive examinations (NDEs) and the delivered CFC for the serial production. The whole manufacturing route is validated if the delivered elements withstand operating conditions similar to those in W7-X in the high heat flux (HHF) test facility GLADIS without degradation of performance and integrity. HHF tests did not show any effect that could be attributed to the CFC grade or to the joining method. The HHF test results exhibited a high percentage of defective tiles, indicated by hot spots at the border of the CFC surface. Visual inspections after HHF tests have mostly correlated these spots to the initiation and /or propagation of cracks at the lateral edge of the tiles in CFC at the interface CFC-copper. The pre-series activities have been extended to reduce the stresses at the critical AMC(r) interface. By means of

  18. A novel dimeric inhibitor targeting Beta2GPI in Beta2GPI/antibody complexes implicated in antiphospholipid syndrome.

    Directory of Open Access Journals (Sweden)

    Alexey Kolyada

    2010-12-01

    Full Text Available β2GPI is a major antigen for autoantibodies associated with antiphospholipid syndrome (APS, an autoimmune disease characterized by thrombosis and recurrent pregnancy loss. Only the dimeric form of β2GPI generated by anti-β2GPI antibodies is pathologically important, in contrast to monomeric β2GPI which is abundant in plasma.We created a dimeric inhibitor, A1-A1, to selectively target β2GPI in β2GPI/antibody complexes. To make this inhibitor, we isolated the first ligand-binding module from ApoER2 (A1 and connected two A1 modules with a flexible linker. A1-A1 interferes with two pathologically important interactions in APS, the binding of β2GPI/antibody complexes with anionic phospholipids and ApoER2. We compared the efficiency of A1-A1 to monomeric A1 for inhibition of the binding of β2GPI/antibody complexes to anionic phospholipids. We tested the inhibition of β2GPI present in human serum, β2GPI purified from human plasma and the individual domain V of β2GPI. We demonstrated that when β2GPI/antibody complexes are formed, A1-A1 is much more effective than A1 in inhibition of the binding of β2GPI to cardiolipin, regardless of the source of β2GPI. Similarly, A1-A1 strongly inhibits the binding of dimerized domain V of β2GPI to cardiolipin compared to the monomeric A1 inhibitor. In the absence of anti-β2GPI antibodies, both A1-A1 and A1 only weakly inhibit the binding of pathologically inactive monomeric β2GPI to cardiolipin.Our results suggest that the approach of using a dimeric inhibitor to block β2GPI in the pathological multivalent β2GPI/antibody complexes holds significant promise. The novel inhibitor A1-A1 may be a starting point in the development of an effective therapeutic for antiphospholipid syndrome.

  19. A Novel Dimeric Inhibitor Targeting Beta2GPI in Beta2GPI/Antibody Complexes Implicated in Antiphospholipid Syndrome

    Energy Technology Data Exchange (ETDEWEB)

    A Kolyada; C Lee; A De Biasio; N Beglova

    2011-12-31

    {beta}2GPI is a major antigen for autoantibodies associated with antiphospholipid syndrome (APS), an autoimmune disease characterized by thrombosis and recurrent pregnancy loss. Only the dimeric form of {beta}2GPI generated by anti-{beta}2GPI antibodies is pathologically important, in contrast to monomeric {beta}2GPI which is abundant in plasma. We created a dimeric inhibitor, A1-A1, to selectively target {beta}2GPI in {beta}2GPI/antibody complexes. To make this inhibitor, we isolated the first ligand-binding module from ApoER2 (A1) and connected two A1 modules with a flexible linker. A1-A1 interferes with two pathologically important interactions in APS, the binding of {beta}2GPI/antibody complexes with anionic phospholipids and ApoER2. We compared the efficiency of A1-A1 to monomeric A1 for inhibition of the binding of {beta}2GPI/antibody complexes to anionic phospholipids. We tested the inhibition of {beta}2GPI present in human serum, {beta}2GPI purified from human plasma and the individual domain V of {beta}2GPI. We demonstrated that when {beta}2GPI/antibody complexes are formed, A1-A1 is much more effective than A1 in inhibition of the binding of {beta}2GPI to cardiolipin, regardless of the source of {beta}2GPI. Similarly, A1-A1 strongly inhibits the binding of dimerized domain V of {beta}2GPI to cardiolipin compared to the monomeric A1 inhibitor. In the absence of anti-{beta}2GPI antibodies, both A1-A1 and A1 only weakly inhibit the binding of pathologically inactive monomeric {beta}2GPI to cardiolipin. Our results suggest that the approach of using a dimeric inhibitor to block {beta}2GPI in the pathological multivalent {beta}2GPI/antibody complexes holds significant promise. The novel inhibitor A1-A1 may be a starting point in the development of an effective therapeutic for antiphospholipid syndrome.

  20. Structure-Based Search for New Inhibitors of Cholinesterases

    Directory of Open Access Journals (Sweden)

    Barbara Malawska

    2013-03-01

    Full Text Available Cholinesterases are important biological targets responsible for regulation of cholinergic transmission, and their inhibitors are used for the treatment of Alzheimer’s disease. To design new cholinesterase inhibitors, of different structure-based design strategies was followed, including the modification of compounds from a previously developed library and a fragment-based design approach. This led to the selection of heterodimeric structures as potential inhibitors. Synthesis and biological evaluation of selected candidates confirmed that the designed compounds were acetylcholinesterase inhibitors with IC50 values in the mid-nanomolar to low micromolar range, and some of them were also butyrylcholinesterase inhibitors.

  1. Discovery of novel, high potent, ABC type PTP1B inhibitors with TCPTP selectivity and cellular activity.

    Science.gov (United States)

    Liu, Peihong; Du, Yongli; Song, Lianhua; Shen, Jingkang; Li, Qunyi

    2016-08-08

    Protein tyrosine phosphatase 1B (PTP1B) as a key negative regulator of both insulin and leptin receptor pathways has been an attractive therapeutic target for the treatment of type 2 diabetes mellitus (T2DM) and obesity. With the goal of enhancing potency and selectivity of the PTP1B inhibitors, a series of methyl salicylate derivatives as ABC type PTP1B inhibitors (P1-P7) were discovered. More importantly, compound P6 exhibited high potent inhibitory activity (IC50 = 50 nM) for PTP1B with 15-fold selectivity over T-cell PTPase (TCPTP). Further studies on cellular activities revealed that compound P6 could enhance insulin-mediated insulin receptor β (IRβ) phosphorylation and insulin-stimulated glucose uptake. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  2. Identification of potential inhibitors based on compound proposal contest: Tyrosine-protein kinase Yes as a target.

    Science.gov (United States)

    Chiba, Shuntaro; Ikeda, Kazuyoshi; Ishida, Takashi; Gromiha, M Michael; Taguchi, Y-H; Iwadate, Mitsuo; Umeyama, Hideaki; Hsin, Kun-Yi; Kitano, Hiroaki; Yamamoto, Kazuki; Sugaya, Nobuyoshi; Kato, Koya; Okuno, Tatsuya; Chikenji, George; Mochizuki, Masahiro; Yasuo, Nobuaki; Yoshino, Ryunosuke; Yanagisawa, Keisuke; Ban, Tomohiro; Teramoto, Reiji; Ramakrishnan, Chandrasekaran; Thangakani, A Mary; Velmurugan, D; Prathipati, Philip; Ito, Junichi; Tsuchiya, Yuko; Mizuguchi, Kenji; Honma, Teruki; Hirokawa, Takatsugu; Akiyama, Yutaka; Sekijima, Masakazu

    2015-11-26

    A search of broader range of chemical space is important for drug discovery. Different methods of computer-aided drug discovery (CADD) are known to propose compounds in different chemical spaces as hit molecules for the same target protein. This study aimed at using multiple CADD methods through open innovation to achieve a level of hit molecule diversity that is not achievable with any particular single method. We held a compound proposal contest, in which multiple research groups participated and predicted inhibitors of tyrosine-protein kinase Yes. This showed whether collective knowledge based on individual approaches helped to obtain hit compounds from a broad range of chemical space and whether the contest-based approach was effective.

  3. [Syk inhibitors].

    Science.gov (United States)

    Kimura, Yukihiro; Chihara, Kazuyasu; Takeuchi, Kenji; Sada, Kiyonao

    2013-07-01

    Non-receptor type of protein-tyrosine kinase Syk (spleen tyrosine kinase) was isolated in the University of Fukui in 1991. Syk is known to be essential for the various physiological functions, especially in hematopoietic lineage cells. Moreover, ectopic expression of Syk by epigenetic changes is reported to cause retinoblastoma. Recently, novel Syk inhibitors were developed and its usefulness has been evaluated in the treatment of allergic rhinitis, rheumatoid arthritis, and idiopathic thrombocytopenic purpura. In this review, we will summarize the history, structure, and function of Syk, and then describe the novel Syk inhibitors and their current status. Furthermore, we will introduce our findings of the adaptor protein 3BP2 (c-Abl SH3 domain-binding protein-2), as a novel target of Syk.

  4. Combined Targeting of JAK2 and Bcl-2/Bcl-xL to Cure Mutant JAK2-Driven Malignancies and Overcome Acquired Resistance to JAK2 Inhibitors

    Directory of Open Access Journals (Sweden)

    Michaela Waibel

    2013-11-01

    Full Text Available To design rational therapies for JAK2-driven hematological malignancies, we functionally dissected the key survival pathways downstream of hyperactive JAK2. In tumors driven by mutant JAK2, Stat1, Stat3, Stat5, and the Pi3k and Mek/Erk pathways were constitutively active, and gene expression profiling of TEL-JAK2 T-ALL cells revealed the upregulation of prosurvival Bcl-2 family genes. Combining the Bcl-2/Bcl-xL inhibitor ABT-737 with JAK2 inhibitors mediated prolonged disease regressions and cures in mice bearing primary human and mouse JAK2 mutant tumors. Moreover, combined targeting of JAK2 and Bcl-2/Bcl-xL was able to circumvent and overcome acquired resistance to single-agent JAK2 inhibitor treatment. Thus, inhibiting the oncogenic JAK2 signaling network at two nodal points, at the initiating stage (JAK2 and the effector stage (Bcl-2/Bcl-xL, is highly effective and provides a clearly superior therapeutic benefit than targeting just one node. Therefore, we have defined a potentially curative treatment for hematological malignancies expressing constitutively active JAK2.

  5. Identification of Small Molecule Translesion Synthesis Inhibitors That Target the Rev1-CT/RIR Protein-Protein Interaction.

    Science.gov (United States)

    Sail, Vibhavari; Rizzo, Alessandro A; Chatterjee, Nimrat; Dash, Radha C; Ozen, Zuleyha; Walker, Graham C; Korzhnev, Dmitry M; Hadden, M Kyle

    2017-07-21

    Translesion synthesis (TLS) is an important mechanism through which proliferating cells tolerate DNA damage during replication. The mutagenic Rev1/Polζ-dependent branch of TLS helps cancer cells survive first-line genotoxic chemotherapy and introduces mutations that can contribute to the acquired resistance so often observed with standard anticancer regimens. As such, inhibition of Rev1/Polζ-dependent TLS has recently emerged as a strategy to enhance the efficacy of first-line chemotherapy and reduce the acquisition of chemoresistance by decreasing tumor mutation rate. The TLS DNA polymerase Rev1 serves as an integral scaffolding protein that mediates the assembly of the active multiprotein TLS complexes. Protein-protein interactions (PPIs) between the C-terminal domain of Rev1 (Rev1-CT) and the Rev1-interacting region (RIR) of other TLS DNA polymerases play an essential role in regulating TLS activity. To probe whether disrupting the Rev1-CT/RIR PPI is a valid approach for developing a new class of targeted anticancer agents, we designed a fluorescence polarization-based assay that was utilized in a pilot screen for small molecule inhibitors of this PPI. Two small molecule scaffolds that disrupt this interaction were identified, and secondary validation assays confirmed that compound 5 binds to Rev1-CT at the RIR interface. Finally, survival and mutagenesis assays in mouse embryonic fibroblasts and human fibrosarcoma HT1080 cells treated with cisplatin and ultraviolet light indicate that these compounds inhibit mutagenic Rev1/Polζ-dependent TLS in cells, validating the Rev1-CT/RIR PPI for future anticancer drug discovery and identifying the first small molecule inhibitors of TLS that target Rev1-CT.

  6. Prospecting for novel plant-derived molecules of Rauvolfia serpentina as inhibitors of Aldose Reductase, a potent drug target for diabetes and its complications.

    Directory of Open Access Journals (Sweden)

    Shivalika Pathania

    Full Text Available Aldose Reductase (AR is implicated in the development of secondary complications of diabetes, providing an interesting target for therapeutic intervention. Extracts of Rauvolfia serpentina, a medicinal plant endemic to the Himalayan mountain range, have been known to be effective in alleviating diabetes and its complications. In this study, we aim to prospect for novel plant-derived inhibitors from R. serpentina and to understand structural basis of their interactions. An extensive library of R. serpentina molecules was compiled and computationally screened for inhibitory action against AR. The stability of complexes, with docked leads, was verified using molecular dynamics simulations. Two structurally distinct plant-derived leads were identified as inhibitors: indobine and indobinine. Further, using these two leads as templates, 16 more leads were identified through ligand-based screening of their structural analogs, from a small molecules database. Thus, we obtained plant-derived indole alkaloids, and their structural analogs, as potential AR inhibitors from a manually curated dataset of R. serpentina molecules. Indole alkaloids reported herein, as a novel structural class unreported hitherto, may provide better insights for designing potential AR inhibitors with improved efficacy and fewer side effects.

  7. Prospecting for novel plant-derived molecules of Rauvolfia serpentina as inhibitors of Aldose Reductase, a potent drug target for diabetes and its complications.

    Science.gov (United States)

    Pathania, Shivalika; Randhawa, Vinay; Bagler, Ganesh

    2013-01-01

    Aldose Reductase (AR) is implicated in the development of secondary complications of diabetes, providing an interesting target for therapeutic intervention. Extracts of Rauvolfia serpentina, a medicinal plant endemic to the Himalayan mountain range, have been known to be effective in alleviating diabetes and its complications. In this study, we aim to prospect for novel plant-derived inhibitors from R. serpentina and to understand structural basis of their interactions. An extensive library of R. serpentina molecules was compiled and computationally screened for inhibitory action against AR. The stability of complexes, with docked leads, was verified using molecular dynamics simulations. Two structurally distinct plant-derived leads were identified as inhibitors: indobine and indobinine. Further, using these two leads as templates, 16 more leads were identified through ligand-based screening of their structural analogs, from a small molecules database. Thus, we obtained plant-derived indole alkaloids, and their structural analogs, as potential AR inhibitors from a manually curated dataset of R. serpentina molecules. Indole alkaloids reported herein, as a novel structural class unreported hitherto, may provide better insights for designing potential AR inhibitors with improved efficacy and fewer side effects.

  8. The binding mechanism of a peptidic cyclic serine protease inhibitor

    DEFF Research Database (Denmark)

    Jiang, Longguang; Svane, Anna Sigrid P.; Sørensen, Hans Peter

    2011-01-01

    Serine proteases are classical objects for studies of catalytic and inhibitory mechanisms as well as interesting as therapeutic targets. Since small-molecule serine protease inhibitors generally suffer from specificity problems, peptidic inhibitors, isolated from phage-displayed peptide libraries......, have attracted considerable attention. Here, we have investigated the mechanism of binding of peptidic inhibitors to serine protease targets. Our model is upain-1 (CSWRGLENHRMC), a disulfide-bond-constrained competitive inhibitor of human urokinase-type plasminogen activator with a noncanonical...... inhibitory mechanism and an unusually high specificity. Using a number of modified variants of upain-1, we characterised the upain-1-urokinase-type plasminogen activator complex using X-ray crystal structure analysis, determined a model of the peptide in solution by NMR spectroscopy, and analysed binding...

  9. Tyrosine-like condensed derivatives as tyrosinase inhibitors.

    Science.gov (United States)

    Matos, Maria João; Santana, Lourdes; Uriarte, Eugenio; Serra, Silvia; Corda, Marcella; Fadda, Maria Benedetta; Era, Benedetta; Fais, Antonella

    2012-05-01

    We report the pharmacological evaluation of a new series of 3-aminocoumarins differently substituted with hydroxyl groups, which have been synthesized because they include in their structures the tyrosine fragment (tyrosine-like compounds), with the aim of discovering structural features necessary for tyrosinase inhibitory activity. The synthesized compounds 4 and 7-9 were evaluated in vitro as mushroom tyrosinase inhibitors. Two of the described compounds showed lower IC50 (concentration giving 50% inhibition of tyrosinase activity) than umbelliferone, used as a reference compound. Compound 7 (IC50=53µm) was the best tyrosinase inhibitor of this small series, having an IC50 value 10-fold lower than umbelliferone. Compound 7 (3-amino-7-hydroxycoumarin) had amino and hydroxyl groups precisely mimicking the same positions that both groups occupy on the tyrosine molecule. © 2012 The Authors. JPP © 2012 Royal Pharmaceutical Society.

  10. EPHA2 is a mediator of vemurafenib resistance and a novel therapeutic target in melanoma.

    Science.gov (United States)

    Miao, Benchun; Ji, Zhenyu; Tan, Li; Taylor, Michael; Zhang, Jianming; Choi, Hwan Geun; Frederick, Dennie T; Kumar, Raj; Wargo, Jennifer A; Flaherty, Keith T; Gray, Nathanael S; Tsao, Hensin

    2015-03-01

    BRAF(V600E) is the most common oncogenic lesion in melanoma and results in constitutive activation of the MAPK pathway and uncontrolled cell growth. Selective BRAF inhibitors such as vemurafenib have been shown to neutralize oncogenic signaling, restrain cellular growth, and improve patient outcome. Although several mechanisms of vemurafenib resistance have been described, directed solutions to overcome these resistance lesions are still lacking. Herein, we found that vemurafenib resistance can be (i) mediated by EPHA2, a member of the largest receptor tyrosine kinases (RTK) subfamily erythropoietin-producing hepatocellular (EPH) receptors, and (ii) associated with a greater phenotypic dependence on EPHA2. Furthermore, we developed a series of first-in-class EPHA2 inhibitors and show that these new compounds potently induce apoptosis, suppress viability, and abrogate tumorigenic growth of melanoma cells, including those that are resistant to vemurafenib. These results provide proof of concept that RTK-guided growth, and therapeutic resistance, can be prospectively defined and selectively targeted. In this study, we show that resistance to selective BRAF inhibitors can be mediated by the RTK EPHA2. Furthermore, direct targeting of EPHA2 can successfully suppress melanoma growth and mitigate therapeutic resistance. ©2014 American Association for Cancer Research.

  11. Model Based Targeting of IL-6-Induced Inflammatory Responses in Cultured Primary Hepatocytes to Improve Application of the JAK Inhibitor Ruxolitinib

    Directory of Open Access Journals (Sweden)

    Svantje Sobotta

    2017-10-01

    Full Text Available IL-6 is a central mediator of the immediate induction of hepatic acute phase proteins (APP in the liver during infection and after injury, but increased IL-6 activity has been associated with multiple pathological conditions. In hepatocytes, IL-6 activates JAK1-STAT3 signaling that induces the negative feedback regulator SOCS3 and expression of APPs. While different inhibitors of IL-6-induced JAK1-STAT3-signaling have been developed, understanding their precise impact on signaling dynamics requires a systems biology approach. Here we present a mathematical model of IL-6-induced JAK1-STAT3 signaling that quantitatively links physiological IL-6 concentrations to the dynamics of IL-6-induced signal transduction and expression of target genes in hepatocytes. The mathematical model consists of coupled ordinary differential equations (ODE and the model parameters were estimated by a maximum likelihood approach, whereas identifiability of the dynamic model parameters was ensured by the Profile Likelihood. Using model simulations coupled with experimental validation we could optimize the long-term impact of the JAK-inhibitor Ruxolitinib, a therapeutic compound that is quickly metabolized. Model-predicted doses and timing of treatments helps to improve the reduction of inflammatory APP gene expression in primary mouse hepatocytes close to levels observed during regenerative conditions. The concept of improved efficacy of the inhibitor through multiple treatments at optimized time intervals was confirmed in primary human hepatocytes. Thus, combining quantitative data generation with mathematical modeling suggests that repetitive treatment with Ruxolitinib is required to effectively target excessive inflammatory responses without exceeding doses recommended by the clinical guidelines.

  12. Small-Molecule Inhibitors of the Type III Secretion System

    Directory of Open Access Journals (Sweden)

    Lingling Gu

    2015-09-01

    Full Text Available Drug-resistant pathogens have presented increasing challenges to the discovery and development of new antibacterial agents. The type III secretion system (T3SS, existing in bacterial chromosomes or plasmids, is one of the most complicated protein secretion systems. T3SSs of animal and plant pathogens possess many highly conserved main structural components comprised of about 20 proteins. Many Gram-negative bacteria carry T3SS as a major virulence determinant, and using the T3SS, the bacteria secrete and inject effector proteins into target host cells, triggering disease symptoms. Therefore, T3SS has emerged as an attractive target for antimicrobial therapeutics. In recent years, many T3SS-targeting small-molecule inhibitors have been discovered; these inhibitors prevent the bacteria from injecting effector proteins and from causing pathophysiology in host cells. Targeting the virulence of Gram-negative pathogens, rather than their survival, is an innovative and promising approach that may greatly reduce selection pressures on pathogens to develop drug-resistant mutations. This article summarizes recent progress in the search for promising small-molecule T3SS inhibitors that target the secretion and translocation of bacterial effector proteins.

  13. Potent selective nonpeptidic inhibitors of human lung tryptase

    OpenAIRE

    Burgess, Laurence E.; Newhouse, Bradley J.; Ibrahim, Prabha; Rizzi, James; Kashem, Mohammed A.; Hartman, Ann; Brandhuber, Barbara J.; Wright, Clifford D.; Thomson, David S.; Vigers, Guy P. A.; Koch, Kevin

    1999-01-01

    Human lung tryptase, a homotetrameric serine protease unique to mast cell secretory granules, has been implicated in the pathogenesis of asthma. A hypothesis that tethered symmetrical inhibitors might bridge two adjacent active sites was explored via a rationally designed series of bisbenzamidines. These compounds demonstrated a remarkable distanced-defined structure–activity relationship against human tryptase with one series possessing subnanomolar potencies. Additional evidence supporting ...

  14. Targeting the Warburg effect with a novel glucose transporter inhibitor to overcome gemcitabine resistance in pancreatic cancer cells

    Science.gov (United States)

    Lai, I-Lu; Chou, Chih-Chien; Lai, Po-Ting; Fang, Chun-Sheng; Shirley, Lawrence A.; Yan, Ribai; Mo, Xiaokui; Bloomston, Mark; Kulp, Samuel K.; Bekaii-Saab, Tanios; Chen, Ching-Shih

    2014-01-01

    Gemcitabine resistance remains a significant clinical challenge. Here, we used a novel glucose transporter (Glut) inhibitor, CG-5, as a proof-of-concept compound to investigate the therapeutic utility of targeting the Warburg effect to overcome gemcitabine resistance in pancreatic cancer. The effects of gemcitabine and/or CG-5 on viability, survival, glucose uptake and DNA damage were evaluated in gemcitabine-sensitive and gemcitabine-resistant pancreatic cancer cell lines. Mechanistic studies were conducted to determine the molecular basis of gemcitabine resistance and the mechanism of CG-5-induced sensitization to gemcitabine. The effects of CG-5 on gemcitabine sensitivity were investigated in a xenograft tumor model of gemcitabine-resistant pancreatic cancer. In contrast to gemcitabine-sensitive pancreatic cancer cells, the resistant Panc-1 and Panc-1GemR cells responded to gemcitabine by increasing the expression of ribonucleotide reductase M2 catalytic subunit (RRM2) through E2F1-mediated transcriptional activation. Acting as a pan-Glut inhibitor, CG-5 abrogated this gemcitabine-induced upregulation of RRM2 through decreased E2F1 expression, thereby enhancing gemcitabine-induced DNA damage and inhibition of cell survival. This CG-5-induced inhibition of E2F1 expression was mediated by the induction of a previously unreported E2F1-targeted microRNA, miR-520f. The addition of oral CG-5 to gemcitabine therapy caused greater suppression of Panc-1GemR xenograft tumor growth in vivo than either drug alone. Glut inhibition may be an effective strategy to enhance gemcitabine activity for the treatment of pancreatic cancer. PMID:24879635

  15. Broad-Spectrum Inhibitors against 3C-Like Proteases of Feline Coronaviruses and Feline Caliciviruses

    Science.gov (United States)

    Shivanna, Vinay; Narayanan, Sanjeev; Prior, Allan M.; Weerasekara, Sahani; Hua, Duy H.; Kankanamalage, Anushka C. Galasiti; Groutas, William C.; Chang, Kyeong-Ok

    2015-01-01

    ABSTRACT Feline infectious peritonitis and virulent, systemic calicivirus infection are caused by certain types of feline coronaviruses (FCoVs) and feline caliciviruses (FCVs), respectively, and are important infectious diseases with high fatality rates in members of the Felidae family. While FCoV and FCV belong to two distinct virus families, the Coronaviridae and the Caliciviridae, respectively, they share a dependence on viral 3C-like protease (3CLpro) for their replication. Since 3CLpro is functionally and structurally conserved among these viruses and essential for viral replication, 3CLpro is considered a potential target for the design of antiviral drugs with broad-spectrum activities against these distinct and highly important viral infections. However, small-molecule inhibitors against the 3CLpro enzymes of FCoV and FCV have not been previously identified. In this study, derivatives of peptidyl compounds targeting 3CLpro were synthesized and evaluated for their activities against FCoV and FCV. The structures of compounds that showed potent dual antiviral activities with a wide margin of safety were identified and are discussed. Furthermore, the in vivo efficacy of 3CLpro inhibitors was evaluated using a mouse model of coronavirus infection. Intraperitoneal administration of two 3CLpro inhibitors in mice infected with murine hepatitis virus A59, a hepatotropic coronavirus, resulted in significant reductions in virus titers and pathological lesions in the liver compared to the findings for the controls. These results suggest that the series of 3CLpro inhibitors described here may have the potential to be further developed as therapeutic agents against these important viruses in domestic and wild cats. This study provides important insights into the structure and function relationships of 3CLpro for the design of antiviral drugs with broader antiviral activities. IMPORTANCE Feline infectious peritonitis virus (FIPV) is the leading cause of death in young cats

  16. 3D QSAR models built on structure-based alignments of Abl tyrosine kinase inhibitors.

    Science.gov (United States)

    Falchi, Federico; Manetti, Fabrizio; Carraro, Fabio; Naldini, Antonella; Maga, Giovanni; Crespan, Emmanuele; Schenone, Silvia; Bruno, Olga; Brullo, Chiara; Botta, Maurizio

    2009-06-01

    Quality QSAR: A combination of docking calculations and a statistical approach toward Abl inhibitors resulted in a 3D QSAR model, the analysis of which led to the identification of ligand portions important for affinity. New compounds designed on the basis of the model were found to have very good affinity for the target, providing further validation of the model itself.The X-ray crystallographic coordinates of the Abl tyrosine kinase domain in its active, inactive, and Src-like inactive conformations were used as targets to simulate the binding mode of a large series of pyrazolo[3,4-d]pyrimidines (known Abl inhibitors) by means of GOLD software. Receptor-based alignments provided by molecular docking calculations were submitted to a GRID-GOLPE protocol to generate 3D QSAR models. Analysis of the results showed that the models based on the inactive and Src-like inactive conformations had very poor statistical parameters, whereas the sole model based on the active conformation of Abl was characterized by significant internal and external predictive ability. Subsequent analysis of GOLPE PLS pseudo-coefficient contour plots of this model gave us a better understanding of the relationships between structure and affinity, providing suggestions for the next optimization process. On the basis of these results, new compounds were designed according to the hydrophobic and hydrogen bond donor and acceptor contours, and were found to have improved enzymatic and cellular activity with respect to parent compounds. Additional biological assays confirmed the important role of the selected compounds as inhibitors of cell proliferation in leukemia cells.

  17. Optimization of Platelet-Derived Growth Factor Receptor (PDGFR) Inhibitors for Duration of Action, as an Inhaled Therapy for Lung Remodeling in Pulmonary Arterial Hypertension.

    Science.gov (United States)

    Shaw, Duncan E; Baig, Ferheen; Bruce, Ian; Chamoin, Sylvie; Collingwood, Stephen P; Cross, Sarah; Dayal, Satish; Drückes, Peter; Furet, Pascal; Furminger, Vikki; Haggart, Deborah; Hussey, Martin; Konstantinova, Irena; Loren, Jon C; Molteni, Valentina; Roberts, Sonia; Reilly, John; Saunders, Alex M; Stringer, Rowan; Sviridenko, Lilya; Thomas, Matthew; Thomson, Christopher G; Tomlins, Christine; Wen, Ben; Yeh, Vince; Pearce, Andrew C

    2016-09-08

    A series of potent PDGFR inhibitors has been identified. The series was optimized for duration of action in the lung. A novel kinase occupancy assay was used to directly measure target occupancy after i.t. dosing. Compound 25 shows 24 h occupancy of the PDGFR kinase domain, after a single i.t. dose and has efficacy at 0.03 mg/kg, in the rat moncrotaline model of pulmonary arterial hypertension. Examination of PK/PD data from the optimization effort has revealed in vitro:in vivo correlations which link duration of action in vivo with low permeability and high basicity and demonstrate that nonspecific binding to lung tissue increases with lipophilicity.

  18. Discovery and Characterization of Substituted Diphenyl Heterocyclic Compounds as Potent and Selective Inhibitors of Hepatitis C Virus Replication▿

    Science.gov (United States)

    Huang, Peiyong; Goff, Dane A.; Huang, Qi; Martinez, Anthony; Xu, Xiang; Crowder, Scott; Issakani, Sarkiz D.; Anderson, Emily; Sheng, Ning; Achacoso, Philip; Yen, Ann; Kinsella, Todd; Darwish, Ihab S.; Kolluri, Rao; Hong, Hui; Qu, Kunbin; Stauffer, Emily; Goldstein, Eileen; Singh, Rajinder; Payan, Donald G.; Lu, H. Henry

    2008-01-01

    A novel small-molecule inhibitor, referred to here as R706, was discovered in a high-throughput screen of chemical libraries against Huh-7-derived replicon cells carrying autonomously replicating subgenomic RNA of hepatitis C virus (HCV). R706 was highly potent in blocking HCV RNA replication as measured by real-time reverse transcription-PCR and Western blotting of R706-treated replicon cells. Structure-activity iterations of the R706 series yielded a lead compound, R803, that was more potent and highly specific for HCV replication, with no significant inhibitory activity against a panel of HCV-related positive-stranded RNA viruses. Furthermore, HCV genotype 1 replicons displayed markedly higher sensitivity to R803 treatment than a genotype 2a-derived replicon. In addition, R803 was tested by a panel of biochemical and cell-based assays for on-target and off-target activities, and the data suggested that the compound had a therapeutic window close to 100-fold, while its exact mechanism of action remained elusive. We found that R803 was more effective than alpha interferon (IFN-α) at blocking HCV RNA replication in the replicon model. In combination studies, R803 showed a weak synergistic effect with IFN-α/ribavirin but only additive effects with a protease inhibitor and an allosteric inhibitor of RNA-dependent RNA polymerase (20). We conclude that R803 and related heterocyclic compounds constitute a new class of HCV-specific inhibitors that could potentially be developed as a treatment for HCV infection. PMID:18227176

  19. Efficient Isothermal Titration Calorimetry Technique Identifies Direct Interaction of Small Molecule Inhibitors with the Target Protein.

    Science.gov (United States)

    Gal, Maayan; Bloch, Itai; Shechter, Nelia; Romanenko, Olga; Shir, Ofer M

    2016-01-01

    Protein-protein interactions (PPI) play a critical role in regulating many cellular processes. Finding novel PPI inhibitors that interfere with specific binding of two proteins is considered a great challenge, mainly due to the complexity involved in characterizing multi-molecular systems and limited understanding of the physical principles governing PPIs. Here we show that the combination of virtual screening techniques, which are capable of filtering a large library of potential small molecule inhibitors, and a unique secondary screening by isothermal titration calorimetry, a label-free method capable of observing direct interactions, is an efficient tool for finding such an inhibitor. In this study we applied this strategy in a search for a small molecule capable of interfering with the interaction of the tumor-suppressor p53 and the E3-ligase MDM2. We virtually screened a library of 15 million small molecules that were filtered to a final set of 80 virtual hits. Our in vitro experimental assay, designed to validate the activity of mixtures of compounds by isothermal titration calorimetry, was used to identify an active molecule against MDM2. At the end of the process the small molecule (4S,7R)-4-(4-chlorophenyl)-5-hydroxy-2,7-dimethyl-N-(6-methylpyridin-2-yl)-4,6,7,8 tetrahydrIoquinoline-3-carboxamide was found to bind MDM2 with a dissociation constant of ~2 µM. Following the identification of this single bioactive compound, spectroscopic measurements were used to further characterize the interaction of the small molecule with the target protein. 2D NMR spectroscopy was used to map the binding region of the small molecule, and fluorescence polarization measurement confirmed that it indeed competes with p53.

  20. Potent Inhibitors against Newcastle Disease Virus Hemagglutinin-Neuraminidase.

    Science.gov (United States)

    Rota, Paola; La Rocca, Paolo; Piccoli, Marco; Montefiori, Marco; Cirillo, Federica; Olsen, Lars; Orioli, Marica; Allevi, Pietro; Anastasia, Luigi

    2018-02-06

    Neuraminidase activity is essential for the infection and propagation of paramyxoviruses, including human parainfluenza viruses (hPIVs) and the Newcastle disease virus (NDV). Thus, many inhibitors have been developed based on the 2-deoxy-2,3-didehydro-d-N-acetylneuraminic acid inhibitor (DANA) backbone. Along this line, herein we report a series of neuraminidase inhibitors, having C4 (p-toluenesulfonamido and azido substituents) and C5 (N-perfluorinated chains) modifications to the DANA backbone, resulting in compounds with 5- to 15-fold greater potency than the currently most active compound, the N-trifluoroacetyl derivative of DANA (FANA), toward the NDV hemagglutinin-neuraminidase (NDV-HN). Remarkably, these inhibitors were found to be essentially inactive against the human sialidase NEU3, which is present on the outer layer of the cell membrane and is highly affected by the current NDV inhibitor FANA. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Obatoclax, a Pan-BCL-2 Inhibitor, Targets Cyclin D1 for Degradation to Induce Antiproliferation in Human Colorectal Carcinoma Cells.

    Science.gov (United States)

    Or, Chi-Hung R; Chang, Yachu; Lin, Wei-Cheng; Lee, Wee-Chyan; Su, Hong-Lin; Cheung, Muk-Wing; Huang, Chang-Po; Ho, Cheesang; Chang, Chia-Che

    2016-12-27

    Colorectal cancer is the third most common cancer worldwide. Aberrant overexpression of antiapoptotic BCL-2 (B-cell lymphoma 2) family proteins is closely linked to tumorigenesis and poor prognosis in colorectal cancer. Obatoclax is an inhibitor targeting all antiapoptotic BCL-2 proteins. A previous study has described the antiproliferative action of obatoclax in one human colorectal cancer cell line without elucidating the underlying mechanisms. We herein reported that, in a panel of human colorectal cancer cell lines, obatoclax inhibits cell proliferation, suppresses clonogenicity, and induces G₁-phase cell cycle arrest, along with cyclin D1 downregulation. Notably, ectopic cyclin D1 overexpression abrogated clonogenicity suppression but also G₁-phase arrest elicited by obatoclax. Mechanistically, pre-treatment with the proteasome inhibitor MG-132 restored cyclin D1 levels in all obatoclax-treated cell lines. Cycloheximide chase analyses further revealed an evident reduction in the half-life of cyclin D1 protein by obatoclax, confirming that obatoclax downregulates cyclin D1 through induction of cyclin D1 proteasomal degradation. Lastly, threonine 286 phosphorylation of cyclin D1, which is essential for initiating cyclin D1 proteasomal degradation, was induced by obatoclax in one cell line but not others. Collectively, we reveal a novel anticancer mechanism of obatoclax by validating that obatoclax targets cyclin D1 for proteasomal degradation to downregulate cyclin D1 for inducing antiproliferation.

  2. Lysine sulfonamides as novel HIV-protease inhibitors: Nepsilon-acyl aromatic alpha-amino acids.

    Science.gov (United States)

    Stranix, Brent R; Lavallée, Jean-François; Sévigny, Guy; Yelle, Jocelyn; Perron, Valérie; LeBerre, Nicholas; Herbart, Dominik; Wu, Jinzi J

    2006-07-01

    A series of lysine sulfonamide analogues bearing Nepsilon-acyl aromatic amino acids were synthesized using an efficient synthetic route. Evaluation of these novel protease inhibitors revealed compounds with high potency against wild-type and multiple-protease inhibitor-resistant HIV viruses.

  3. Peptide deformylase as an antibacterial drug target: target validation and resistance development.

    Science.gov (United States)

    Apfel, C M; Locher, H; Evers, S; Takács, B; Hubschwerlen, C; Pirson, W; Page, M G; Keck, W

    2001-04-01

    New inhibitors of peptide deformylase (PDF) which are very potent against the isolated enzyme and show a certain degree of antibacterial activity have recently been synthesized by our group. Several lines of experimental evidence indicate that these inhibitors indeed interfere with the target enzyme in the bacterial cell. (i) The inhibition of Escherichia coli growth could be counteracted by overexpression of PDF from different organisms, including E. coli, Streptococcus pneumoniae, and Haemophilus influenzae. Conversely, reduced expression of PDF in S. pneumoniae resulted in an increased susceptibility to the inhibitors. (ii) Proteome analysis on two-dimensional gels revealed a shift for many proteins towards lower pI in the presence of PDF inhibitors, as would be expected if the proteins still carry their N-formyl-Met terminus. (iii) PDF inhibitors show no antimicrobial activity against E. coli under conditions that make growth independent of formylation and deformylation. The antibacterial activity in E. coli was characterized as bacteriostatic. Furthermore, the development of resistance in E. coli was observed to occur with high frequency (10(-7)). Resistant mutants show a reduced growth rate, and DNA sequence analysis revealed mutations in their formyl transferase gene. Taking all these aspects into account, we conclude that PDF may not be an optimal target for broad-spectrum antibacterial agents.

  4. First report on 3D-QSAR and molecular dynamics based docking studies of GCPII inhibitors for targeted drug delivery applications

    Science.gov (United States)

    Pandit, Amit; Sengupta, Sagnik; Krishnan, Mena Asha; Reddy, Ramesh B.; Sharma, Rajesh; Venkatesh, Chelvam

    2018-05-01

    Prostate Specific Membrane Antigen (PSMA) or Glutamate carboxypeptidase II (GCPII) has been identified as an important target in diagnosis and therapy of prostate cancer. Among several types of inhibitors, urea based inhibitors are the most common and widely employed in preclinical and clinical studies. Computational studies have been carried out to uncover active sites and interaction of PSMA inhibitors with the protein by modifying the core structure of the ligand. Analysis of the literature, however, show lack of 3-D quantitative structure activity relationship (QSAR) and molecular dynamics based molecular docking study to identify structural modifications responsible for better GCPII inhibitory activity. The present study aims to fulfil this gap by analysing well known PSMA inhibitors reported in the literature with known experimental PSMA inhibition constants. Also in order to validate the in silico study, a new GCPII inhibitor 7 was designed, synthesized and experimental PSMA enzyme inhibition was evaluated by using freshly isolated PSMA protein from human cancer cell line derived from lymph node, LNCaP. 3D-QSAR CoMFA models on 58 urea based GCPII inhibitors were generated, and the best correlation was obtained in Gast-Huck charge assigning method with q2, r2 and predictive r2 values as 0.592, 0.995 and 0.842 respectively. Moreover, steric, electrostatic, and hydrogen bond donor field contribution analysis provided best statistical values from CoMSIA model (q2, r2 and predictive r2 as 0.527, 0.981 and 0.713 respectively). Contour maps study revealed that electrostatic field contribution is the major factor for discovering better binding affinity ligands. Further molecular dynamic assisted molecular docking was also performed on GCPII receptor (PDB ID 4NGM) and most active GCPII inhibitor, DCIBzL. 4NGM co-crystallised ligand, JB7 was used to validate the docking procedure and the amino acid interactions present in JB7 are compared with DCIBzL. The results

  5. A resurgence of β-lactamase inhibitor combinations effective against multidrug-resistant Gram-negative pathogens.

    Science.gov (United States)

    Bush, Karen

    2015-11-01

    β-Lactamase inhibitors (BLIs) have played an important role in combatting β-lactam resistance in Gram-negative bacteria, but their effectiveness has diminished with the evolution of diverse and deleterious varieties of β-lactamases. In this review, a new generation of BLIs and inhibitor combinations is presented, describing epidemiological information, pharmacodynamic studies, resistance identification and current clinical status. Novel serine BLIs of major interest include the non-β-lactams of the diazabicyclo[3.2.1]octanone (DBO) series. The DBOs avibactam, relebactam and RG6080 inhibit most class A and class C β-lactamases, with selected inhibition of class D enzymes by avibactam. The novel boronic acid inhibitor RPX7009 has a similar inhibitory profile. All of these inhibitors are being developed in combinations that are targeting primarily carbapenemase-producing Gram-negative pathogens. Two BLI combinations (ceftolozane/tazobactam and ceftazidime/avibactam) were recently approved by the US Food and Drug Administration (FDA) under the designation of a Qualified Infectious Disease Product (QIDP). Other inhibitor combinations that have at least completed phase 1 clinical trials are ceftaroline fosamil/avibactam, aztreonam/avibactam, imipenem/relebactam, meropenem/RPX7009 and cefepime/AAI101. Although effective inhibitor combinations are in development for the treatment of infections caused by Gram-negative bacteria with serine carbapenemases, better options are still necessary for pathogens that produce metallo-β-lactamases (MBLs). The aztreonam/avibactam combination demonstrates inhibitory activity against MBL-producing enteric bacteria owing to the stability of the monobactam to these enzymes, but resistance is still an issue for MBL-producing non-fermentative bacteria. Because all of the inhibitor combinations are being developed as parenteral drugs, an orally bioavailable combination would also be of interest. Copyright © 2015 Elsevier B.V. and the

  6. SAH derived potent and selective EZH2 inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Kung, Pei-Pei; Huang, Buwen; Zehnder, Luke; Tatlock, John; Bingham, Patrick; Krivacic, Cody; Gajiwala, Ketan; Diehl, Wade; Yu, Xiu; Maegley, Karen A.

    2015-04-01

    A series of novel enhancer of zeste homolog 2 (EZH2) inhibitors was designed based on the chemical structure of the histone methyltransferase (HMT) inhibitor SAH (S-adenosyl-l-homocysteine). These nucleoside-based EZH2 inhibitors blocked the methylation of nucleosomes at H3K27 in biochemical assays employing both WT PRC2 complex as well as a Y641N mutant PRC2 complex. The most potent compound, 27, displayed IC50’s against both complexes of 270 nM and 70 nM, respectively. To our knowledge, compound 27 is the most potent SAH-derived inhibitor of the EZH2 PRC2 complex yet identified. This compound also displayed improved potency, lipophilic efficiency (LipE), and selectivity profile against other lysine methyltransferases compared with SAH.

  7. Peptide-Based Selective Inhibitors of Matrix Metalloproteinase-Mediated Activities

    Directory of Open Access Journals (Sweden)

    Margaret W. Ndinguri

    2012-11-01

    Full Text Available The matrix metalloproteinases (MMPs exhibit a broad array of activities, some catalytic and some non-catalytic in nature. An overall lack of selectivity has rendered small molecule, active site targeted MMP inhibitors problematic in execution. Inhibitors that favor few or individual members of the MMP family often take advantage of interactions outside the enzyme active site. We presently focus on peptide-based MMP inhibitors and probes that do not incorporate conventional Zn2+ binding groups. In some cases, these inhibitors and probes function by binding only secondary binding sites (exosites, while others bind both exosites and the active site. A myriad of MMP mediated-activities beyond selective catalysis can be inhibited by peptides, particularly cell adhesion, proliferation, motility, and invasion. Selective MMP binding peptides comprise highly customizable, unique imaging agents. Areas of needed improvement for MMP targeting peptides include binding affinity and stability.

  8. Recent advances in botulinum neurotoxin inhibitor development.

    Science.gov (United States)

    Kiris, Erkan; Burnett, James C; Kane, Christopher D; Bavari, Sina

    2014-01-01

    Botulinum neurotoxins (BoNTs) are endopeptidases that target motor neurons and block acetylcholine neurotransmitter release. This action results in the muscle paralysis that defines the disease botulism. To date, there are no FDA-approved therapeutics to treat BoNT-mediated paralysis after intoxication of the motor neuron. Importantly, the rationale for pursuing treatments to counter these toxins is driven by their potential misuse. Current drug discovery efforts have mainly focused on small molecules, peptides, and peptidomimetics that can directly and competitively inhibit BoNT light chain proteolytic activity. Although this is a rational approach, direct inhibition of the Zn(2+) metalloprotease activity has been elusive as demonstrated by the dearth of candidates undergoing clinical evaluation. Therefore, broadening the scope of viable targets beyond that of active site protease inhibitors represents an additional strategy that could move the field closer to the clinic. Here we review the rationale, and discuss the outcomes of earlier approaches and highlight potential new targets for BoNT inhibition. These include BoNT uptake and processing inhibitors, enzymatic inhibitors, and modulators of neuronal processes associated with toxin clearance, neurotransmitter potentiation, and other pathways geared towards neuronal recovery and repair.

  9. Kinetic modelling of in vitro data of PI3K, mTOR1, PTEN enzymes and on-target inhibitors Rapamycin, BEZ235, and LY294002.

    Science.gov (United States)

    Goltsov, Alexey; Tashkandi, Ghassan; Langdon, Simon P; Harrison, David J; Bown, James L

    2017-01-15

    The phosphatidylinositide 3-kinases (PI3K) and mammalian target of rapamycin-1 (mTOR1) are two key targets for anti-cancer therapy. Predicting the response of the PI3K/AKT/mTOR1 signalling pathway to targeted therapy is made difficult because of network complexities. Systems biology models can help explore those complexities but the value of such models is dependent on accurate parameterisation. Motivated by a need to increase accuracy in kinetic parameter estimation, and therefore the predictive power of the model, we present a framework to integrate kinetic data from enzyme assays into a unified enzyme kinetic model. We present exemplar kinetic models of PI3K and mTOR1, calibrated on in vitro enzyme data and founded on Michaelis-Menten (MM) approximation. We describe the effects of an allosteric mTOR1 inhibitor (Rapamycin) and ATP-competitive inhibitors (BEZ235 and LY294002) that show dual inhibition of mTOR1 and PI3K. We also model the kinetics of phosphatase and tensin homolog (PTEN), which modulates sensitivity of the PI3K/AKT/mTOR1 pathway to these drugs. Model validation with independent data sets allows investigation of enzyme function and drug dose dependencies in a wide range of experimental conditions. Modelling of the mTOR1 kinetics showed that Rapamycin has an IC 50 independent of ATP concentration and that it is a selective inhibitor of mTOR1 substrates S6K1 and 4EBP1: it retains 40% of mTOR1 activity relative to 4EBP1 phosphorylation and inhibits completely S6K1 activity. For the dual ATP-competitive inhibitors of mTOR1 and PI3K, LY294002 and BEZ235, we derived the dependence of the IC 50 on ATP concentration that allows prediction of the IC 50 at different ATP concentrations in enzyme and cellular assays. Comparison of drug effectiveness in enzyme and cellular assays showed that some features of these drugs arise from signalling modulation beyond the on-target action and MM approximation and require a systems-level consideration of the whole PI3K

  10. Designing of phenol-based β-carbonic anhydrase1 inhibitors through QSAR, molecular docking, and MD simulation approach.

    Science.gov (United States)

    Ahamad, Shahzaib; Hassan, Md Imtaiyaz; Dwivedi, Neeraja

    2018-05-01

    Tuberculosis (Tb) is an airborne infectious disease caused by Mycobacterium tuberculosis. Beta-carbonic anhydrase 1 ( β-CA1 ) has emerged as one of the potential targets for new antitubercular drug development. In this work, three-dimensional quantitative structure-activity relationships (3D-QSAR), molecular docking, and molecular dynamics (MD) simulation approaches were performed on a series of natural and synthetic phenol-based β-CA1 inhibitors. The developed 3D-QSAR model ( r 2  = 0.94, q 2  = 0.86, and pred_r 2  = 0.74) indicated that the steric and electrostatic factors are important parameters to modulate the bioactivity of phenolic compounds. Based on this indication, we designed 72 new phenolic inhibitors, out of which two compounds (D25 and D50) effectively stabilized β-CA1 receptor and, thus, are potential candidates for new generation antitubercular drug discovery program.

  11. Prostate-specific membrane antigen targeted imaging and therapy of prostate cancer using a PSMA inhibitor as a homing ligand.

    Science.gov (United States)

    Kularatne, Sumith A; Wang, Kevin; Santhapuram, Hari-Krishna R; Low, Philip S

    2009-01-01

    Prostate cancer (PCa) is a major cause of mortality and morbidity in Western society today. Current methods for detecting PCa are limited, leaving most early malignancies undiagnosed and sites of metastasis in advanced disease undetected. Major deficiencies also exist in the treatment of PCa, especially metastatic disease. In an effort to improve both detection and therapy of PCa, we have developed a PSMA-targeted ligand that delivers attached imaging and therapeutic agents selectively to PCa cells without targeting normal cells. The PSMA-targeted radioimaging agent (DUPA-(99m)Tc) was found to bind PSMA-positive human PCa cells (LNCaP cell line) with nanomolar affinity (K(D) = 14 nM). Imaging and biodistribution studies revealed that DUPA-(99m)Tc localizes primarily to LNCaP cell tumor xenografts in nu/nu mice (% injected dose/gram = 11.3 at 4 h postinjection; tumor-to-muscle ratio = 75:1). Two PSMA-targeted optical imaging agents (DUPA-FITC and DUPA-rhodamine B) were also shown to efficiently label PCa cells and to internalize and traffic to intracellular endosomes. A PSMA-targeted chemotherapeutic agent (DUPA-TubH) was demonstrated to kill PSMA-positive LNCaP cells in culture (IC(50) = 3 nM) and to eliminate established tumor xenografts in nu/nu mice with no detectable weight loss. Blockade of tumor targeting upon administration of excess PSMA inhibitor (PMPA) and the absence of targeting to PSMA-negative tumors confirmed the specificity of each of the above targeted reagents for PSMA. Tandem use of the imaging and therapeutic agents targeted to the same receptor could allow detection, staging, monitoring, and treatment of PCa with improved accuracy and efficacy.

  12. Role of mTOR Inhibitors in Kidney Disease

    Directory of Open Access Journals (Sweden)

    Moto Kajiwara

    2016-06-01

    Full Text Available The first compound that inhibited the mammalian target of rapamycin (mTOR, sirolimus (rapamycin was discovered in the 1970s as a soil bacterium metabolite collected on Easter Island (Rapa Nui. Because sirolimus showed antiproliferative activity, researchers investigated its molecular target and identified the TOR1 and TOR2. The mTOR consists of mTOR complex 1 (mTORC1 and mTORC2. Rapalogues including sirolimus, everolimus, and temsirolimus exert their effect mainly on mTORC1, whereas their inhibitory effect on mTORC2 is mild. To obtain compounds with more potent antiproliferative effects, ATP-competitive inhibitors of mTOR targeting both mTORC1 and mTORC2 have been developed and tested in clinical trials as anticancer drugs. Currently, mTOR inhibitors are used as anticancer drugs against several solid tumors, and immunosuppressive agents for transplantation of various organs. This review discusses the role of mTOR inhibitors in renal disease with a particular focus on renal cancer, diabetic nephropathy, and kidney transplantation.

  13. Modelling of potentially promising SARS protease inhibitors

    International Nuclear Information System (INIS)

    Plewczynski, Dariusz; Hoffmann, Marcin; Grotthuss, Marcin von; Knizewski, Lukasz; Rychewski, Leszek; Eitner, Krystian; Ginalski, Krzysztof

    2007-01-01

    In many cases, at the beginning of a high throughput screening experiment some information about active molecules is already available. Active compounds (such as substrate analogues, natural products and inhibitors of related proteins) are often identified in low throughput validation studies on a biochemical target. Sometimes the additional structural information is also available from crystallographic studies on protein and ligand complexes. In addition, the structural or sequence similarity of various protein targets yields a novel possibility for drug discovery. Co-crystallized compounds from homologous proteins can be used to design leads for a new target without co-crystallized ligands. In this paper we evaluate how far such an approach can be used in a real drug campaign, with severe acute respiratory syndrome (SARS) coronavirus providing an example. Our method is able to construct small molecules as plausible inhibitors solely on the basis of the set of ligands from crystallized complexes of a protein target, and other proteins from its structurally homologous family. The accuracy and sensitivity of the method are estimated here by the subsequent use of an electronic high throughput screening flexible docking algorithm. The best performing ligands are then used for a very restrictive similarity search for potential inhibitors of the SARS protease within the million compounds from the Ligand.Info small molecule meta-database. The selected molecules can be passed on for further experimental validation

  14. Modelling of potentially promising SARS protease inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Plewczynski, Dariusz [Interdisciplinary Centre for Mathematical and Computational Modelling, ICM, Warsaw University, Pawinskiego 5a Street, 02-106 Warsaw (Poland); Hoffmann, Marcin [BioInfoBank Institute, Limanowskiego 24A/16, 60-744 Poznan (Poland); Grotthuss, Marcin von [BioInfoBank Institute, Limanowskiego 24A/16, 60-744 Poznan (Poland); Knizewski, Lukasz [Interdisciplinary Centre for Mathematical and Computational Modelling, ICM, Warsaw University, Pawinskiego 5a Street, 02-106 Warsaw (Poland); Rychewski, Leszek [BioInfoBank Institute, Limanowskiego 24A/16, 60-744 Poznan (Poland); Eitner, Krystian [BioInfoBank Institute, Limanowskiego 24A/16, 60-744 Poznan (Poland); Ginalski, Krzysztof [Interdisciplinary Centre for Mathematical and Computational Modelling, ICM, Warsaw University, Pawinskiego 5a Street, 02-106 Warsaw (Poland)

    2007-07-18

    In many cases, at the beginning of a high throughput screening experiment some information about active molecules is already available. Active compounds (such as substrate analogues, natural products and inhibitors of related proteins) are often identified in low throughput validation studies on a biochemical target. Sometimes the additional structural information is also available from crystallographic studies on protein and ligand complexes. In addition, the structural or sequence similarity of various protein targets yields a novel possibility for drug discovery. Co-crystallized compounds from homologous proteins can be used to design leads for a new target without co-crystallized ligands. In this paper we evaluate how far such an approach can be used in a real drug campaign, with severe acute respiratory syndrome (SARS) coronavirus providing an example. Our method is able to construct small molecules as plausible inhibitors solely on the basis of the set of ligands from crystallized complexes of a protein target, and other proteins from its structurally homologous family. The accuracy and sensitivity of the method are estimated here by the subsequent use of an electronic high throughput screening flexible docking algorithm. The best performing ligands are then used for a very restrictive similarity search for potential inhibitors of the SARS protease within the million compounds from the Ligand.Info small molecule meta-database. The selected molecules can be passed on for further experimental validation.

  15. Rapid synthesis of triazine inhibitors of inosine monophosphate dehydrogenase.

    Science.gov (United States)

    Pitts, William J; Guo, Junqing; Dhar, T G Murali; Shen, Zhongqi; Gu, Henry H; Watterson, Scott H; Bednarz, Mark S; Chen, Bang Chi; Barrish, Joel C; Bassolino, Donna; Cheney, Daniel; Fleener, Catherine A; Rouleau, Katherine A; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2002-08-19

    A series of novel triazine-based small molecule inhibitors (IV) of inosine monophosphate dehydrogenase was prepared. The synthesis and the structure-activity relationships (SAR) derived from in vitro studies are described.

  16. Novel amide-based inhibitors of inosine 5'-monophosphate dehydrogenase.

    Science.gov (United States)

    Watterson, Scott H; Liu, Chunjian; Dhar, T G Murali; Gu, Henry H; Pitts, William J; Barrish, Joel C; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2002-10-21

    A series of novel amide-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are described.

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

    Directory of Open Access Journals (Sweden)

    Li W

    2016-10-01

    Full Text Available Wenbo Li,1,* Lijie Dong,1,* Minwang Ma,2,* Bojie Hu,1 Zhenyu Lu,3 Xun Liu,1 Juping Liu,1 Xiaorong Li1 1Tianjin Medical University Eye Hospital, Tianjin, People’s Republic of China; 2Affiliated Hospital of Medical College of Chinese People’s Armed Police Forces (CapF, Tianjin, People’s Republic of China; 3Tianjin Precision Cell Biotechnology Co. Ltd., Tianjin, People’s Republic of China *These authors contributed equally to this work Abstract: 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. Keywords: choroidal neovascularization, macular degeneration, complement activation, vascular endothelial growth factor

  18. Insight into the mechanism of action and selectivity of caspase-3 reversible inhibitors through in silico studies

    Science.gov (United States)

    Minini, Lucía; Ferraro, Florencia; Cancela, Saira; Merlino, Alicia

    2017-11-01

    Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder worldwide for which there is currently no cure. Recently, caspase-3 has been proposed as a potential therapeutic target for treating AD. Since this enzyme is overexpressed in brains from AD patients its selective modulation by non-covalent inhibitors becomes an interesting strategy in the search of potential drugs against this neuropathology. With this in mind, we have combined molecular docking, molecular dynamics simulations and QM calculations of unliganded caspase-3 and caspase-7 and in complex with a series of known inhibitors of caspase-3 described in the literature in order to assess the structural features responsible for good inhibitory activity and selectivity against this potential target. This work has allowed us to identify hotspots for drug binding as well as the importance of shape and charge distribution for interacting into the substrate binding cleft or into the dimer interface in each enzyme. Our results showed that most selective compounds against caspsase-3 bind into the substrate binding cleft acting as competitive inhibitors whereas in caspase-7 they bind close to an allosteric site at the dimer interface but since they are weakly bound their presence would not be affecting enzyme dynamics or function. In addition, for both enzymes we have found evidence indicating that differences in shape and accessibility exist between the substrate binding site of each monomer which could be modulating the binding affinity of non-covalent molecules.

  19. Structures of Trypanosoma brucei methionyl-tRNA synthetase with urea-based inhibitors provide guidance for drug design against sleeping sickness.

    Directory of Open Access Journals (Sweden)

    Cho Yeow Koh

    2014-04-01

    Full Text Available Methionyl-tRNA synthetase of Trypanosoma brucei (TbMetRS is an important target in the development of new antitrypanosomal drugs. The enzyme is essential, highly flexible and displaying a large degree of changes in protein domains and binding pockets in the presence of substrate, product and inhibitors. Targeting this protein will benefit from a profound understanding of how its structure adapts to ligand binding. A series of urea-based inhibitors (UBIs has been developed with IC50 values as low as 19 nM against the enzyme. The UBIs were shown to be orally available and permeable through the blood-brain barrier, and are therefore candidates for development of drugs for the treatment of late stage human African trypanosomiasis. Here, we expand the structural diversity of inhibitors from the previously reported collection and tested for their inhibitory effect on TbMetRS and on the growth of T. brucei cells. The binding modes and binding pockets of 14 UBIs are revealed by determination of their crystal structures in complex with TbMetRS at resolutions between 2.2 Å to 2.9 Å. The structures show binding of the UBIs through conformational selection, including occupancy of the enlarged methionine pocket and the auxiliary pocket. General principles underlying the affinity of UBIs for TbMetRS are derived from these structures, in particular the optimum way to fill the two binding pockets. The conserved auxiliary pocket might play a role in binding tRNA. In addition, a crystal structure of a ternary TbMetRS•inhibitor•AMPPCP complex indicates that the UBIs are not competing with ATP for binding, instead are interacting with ATP through hydrogen bond. This suggests a possibility that a general 'ATP-engaging' binding mode can be utilized for the design and development of inhibitors targeting tRNA synthetases of other disease-causing pathogen.

  20. Identification of the quinolinedione inhibitor binding site in Cdc25 phosphatase B through docking and molecular dynamics simulations

    Science.gov (United States)

    Ge, Yushu; van der Kamp, Marc; Malaisree, Maturos; Liu, Dan; Liu, Yi; Mulholland, Adrian J.

    2017-11-01

    Cdc25 phosphatase B, a potential target for cancer therapy, is inhibited by a series of quinones. The binding site and mode of quinone inhibitors to Cdc25B remains unclear, whereas this information is important for structure-based drug design. We investigated the potential binding site of NSC663284 [DA3003-1 or 6-chloro-7-(2-morpholin-4-yl-ethylamino)-quinoline-5, 8-dione] through docking and molecular dynamics simulations. Of the two main binding sites suggested by docking, the molecular dynamics simulations only support one site for stable binding of the inhibitor. Binding sites in and near the Cdc25B catalytic site that have been suggested previously do not lead to stable binding in 50 ns molecular dynamics (MD) simulations. In contrast, a shallow pocket between the C-terminal helix and the catalytic site provides a favourable binding site that shows high stability. Two similar binding modes featuring protein-inhibitor interactions involving Tyr428, Arg482, Thr547 and Ser549 are identified by clustering analysis of all stable MD trajectories. The relatively flexible C-terminal region of Cdc25B contributes to inhibitor binding. The binding mode of NSC663284, identified through MD simulation, likely prevents the binding of protein substrates to Cdc25B. The present results provide useful information for the design of quinone inhibitors and their mechanism of inhibition.

  1. Identification of the quinolinedione inhibitor binding site in Cdc25 phosphatase B through docking and molecular dynamics simulations.

    Science.gov (United States)

    Ge, Yushu; van der Kamp, Marc; Malaisree, Maturos; Liu, Dan; Liu, Yi; Mulholland, Adrian J

    2017-11-01

    Cdc25 phosphatase B, a potential target for cancer therapy, is inhibited by a series of quinones. The binding site and mode of quinone inhibitors to Cdc25B remains unclear, whereas this information is important for structure-based drug design. We investigated the potential binding site of NSC663284 [DA3003-1 or 6-chloro-7-(2-morpholin-4-yl-ethylamino)-quinoline-5, 8-dione] through docking and molecular dynamics simulations. Of the two main binding sites suggested by docking, the molecular dynamics simulations only support one site for stable binding of the inhibitor. Binding sites in and near the Cdc25B catalytic site that have been suggested previously do not lead to stable binding in 50 ns molecular dynamics (MD) simulations. In contrast, a shallow pocket between the C-terminal helix and the catalytic site provides a favourable binding site that shows high stability. Two similar binding modes featuring protein-inhibitor interactions involving Tyr428, Arg482, Thr547 and Ser549 are identified by clustering analysis of all stable MD trajectories. The relatively flexible C-terminal region of Cdc25B contributes to inhibitor binding. The binding mode of NSC663284, identified through MD simulation, likely prevents the binding of protein substrates to Cdc25B. The present results provide useful information for the design of quinone inhibitors and their mechanism of inhibition.

  2. Reversible targeting of noncatalytic cysteines with chemically tuned electrophiles

    DEFF Research Database (Denmark)

    Serafimova, Iana M; Pufall, Miles A; Krishnan, Shyam

    2012-01-01

    Targeting noncatalytic cysteine residues with irreversible acrylamide-based inhibitors is a powerful approach for enhancing pharmacological potency and selectivity. Nevertheless, concerns about off-target modification motivate the development of reversible cysteine-targeting strategies. Here we...... of these electrophiles into a noncovalent kinase-recognition scaffold produced slowly dissociating, covalent inhibitors of the p90 ribosomal protein S6 kinase RSK2. A cocrystal structure revealed specific noncovalent interactions that stabilize the complex by positioning the electrophilic carbon near the targeted...

  3. Inhibitors of mTOR

    NARCIS (Netherlands)

    Klümpen, Heinz-Josef; Beijnen, Jos H.; Gurney, Howard; Schellens, Jan H. M.

    2010-01-01

    Inhibitors of mammalian target of rapamycin (mTOR) have been approved for the treatment of renal cell carcinoma and appear to have a role in the treatment of other malignancies. The primary objective of this drug review is to provide pharmacokinetic and dynamic properties of the commonly used drugs

  4. Discovery of amido-benzisoxazoles as potent c-Kit inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Kunz, Roxanne K.; Rumfelt, Shannon; Chen, Ning; Zhang, Dawei; Tasker, Andrew S.; Bürli, Roland; Hungate, Randall; Yu, Violeta; Nguyen, Yen; Whittington, Douglas A.; Meagher, Kristin L.; Plant, Matthew; Tudor, Yanyan; Schrag, Michael; Xu, Yang; Ng, Gordon Y.; Hu, Essa (Amgen)

    2010-01-12

    Deregulation of the receptor tyrosine kinase c-Kit is associated with an increasing number of human diseases, including certain cancers and mast cell diseases. Interference of c-Kit signaling with multi-kinase inhibitors has been shown clinically to successfully treat gastrointestinal stromal tumors and mastocytosis. Targeted therapy of c-Kit activity may provide therapeutic advantages against off-target effects for non-oncology applications. A new structural class of c-Kit inhibitors is described, including in vitro c-Kit potency, kinase selectivity, and the observed binding mode.

  5. Developmental defects in zebrafish for classification of EGF pathway inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Pruvot, Benoist; Curé, Yoann; Djiotsa, Joachim; Voncken, Audrey; Muller, Marc, E-mail: m.muller@ulg.ac.be

    2014-01-15

    One of the major challenges when testing drug candidates targeted at a specific pathway in whole animals is the discrimination between specific effects and unwanted, off-target effects. Here we used the zebrafish to define several developmental defects caused by impairment of Egf signaling, a major pathway of interest in tumor biology. We inactivated Egf signaling by genetically blocking Egf expression or using specific inhibitors of the Egf receptor function. We show that the combined occurrence of defects in cartilage formation, disturbance of blood flow in the trunk and a decrease of myelin basic protein expression represent good indicators for impairment of Egf signaling. Finally, we present a classification of known tyrosine kinase inhibitors according to their specificity for the Egf pathway. In conclusion, we show that developmental indicators can help to discriminate between specific effects on the target pathway from off-target effects in molecularly targeted drug screening experiments in whole animal systems. - Highlights: • We analyze the functions of Egf signaling on zebrafish development. • Genetic blocking of Egf expression causes cartilage, myelin and circulatory defects. • Chemical inhibition of Egf receptor function causes similar defects. • Developmental defects can reveal the specificity of Egf pathway inhibitors.

  6. Developmental defects in zebrafish for classification of EGF pathway inhibitors

    International Nuclear Information System (INIS)

    Pruvot, Benoist; Curé, Yoann; Djiotsa, Joachim; Voncken, Audrey; Muller, Marc

    2014-01-01

    One of the major challenges when testing drug candidates targeted at a specific pathway in whole animals is the discrimination between specific effects and unwanted, off-target effects. Here we used the zebrafish to define several developmental defects caused by impairment of Egf signaling, a major pathway of interest in tumor biology. We inactivated Egf signaling by genetically blocking Egf expression or using specific inhibitors of the Egf receptor function. We show that the combined occurrence of defects in cartilage formation, disturbance of blood flow in the trunk and a decrease of myelin basic protein expression represent good indicators for impairment of Egf signaling. Finally, we present a classification of known tyrosine kinase inhibitors according to their specificity for the Egf pathway. In conclusion, we show that developmental indicators can help to discriminate between specific effects on the target pathway from off-target effects in molecularly targeted drug screening experiments in whole animal systems. - Highlights: • We analyze the functions of Egf signaling on zebrafish development. • Genetic blocking of Egf expression causes cartilage, myelin and circulatory defects. • Chemical inhibition of Egf receptor function causes similar defects. • Developmental defects can reveal the specificity of Egf pathway inhibitors

  7. Perturbation biology nominates upstream-downstream drug combinations in RAF inhibitor resistant melanoma cells.

    Science.gov (United States)

    Korkut, Anil; Wang, Weiqing; Demir, Emek; Aksoy, Bülent Arman; Jing, Xiaohong; Molinelli, Evan J; Babur, Özgün; Bemis, Debra L; Onur Sumer, Selcuk; Solit, David B; Pratilas, Christine A; Sander, Chris

    2015-08-18

    Resistance to targeted cancer therapies is an important clinical problem. The discovery of anti-resistance drug combinations is challenging as resistance can arise by diverse escape mechanisms. To address this challenge, we improved and applied the experimental-computational perturbation biology method. Using statistical inference, we build network models from high-throughput measurements of molecular and phenotypic responses to combinatorial targeted perturbations. The models are computationally executed to predict the effects of thousands of untested perturbations. In RAF-inhibitor resistant melanoma cells, we measured 143 proteomic/phenotypic entities under 89 perturbation conditions and predicted c-Myc as an effective therapeutic co-target with BRAF or MEK. Experiments using the BET bromodomain inhibitor JQ1 affecting the level of c-Myc protein and protein kinase inhibitors targeting the ERK pathway confirmed the prediction. In conclusion, we propose an anti-cancer strategy of co-targeting a specific upstream alteration and a general downstream point of vulnerability to prevent or overcome resistance to targeted drugs.

  8. The regulatory mechanism of fruit ripening revealed by analyses of direct targets of the tomato MADS-box transcription factor RIPENING INHIBITOR

    Science.gov (United States)

    Fujisawa, Masaki; Ito, Yasuhiro

    2013-01-01

    The developmental process of ripening is unique to fleshy fruits and a key factor in fruit quality. The tomato (Solanum lycopersicum) MADS-box transcription factor RIPENING INHIBITOR (RIN), one of the earliest-acting ripening regulators, is required for broad aspects of ripening, including ethylene-dependent and -independent pathways. However, our knowledge of direct RIN target genes has been limited, considering the broad effects of RIN on ripening. In a recent work published in The Plant Cell, we identified 241 direct RIN target genes by chromatin immunoprecipitation coupled with DNA microarray (ChIP-chip) and transcriptome analysis. Functional classification of the targets revealed that RIN participates in the regulation of many biological processes including well-known ripening processes such as climacteric ethylene production and lycopene accumulation. In addition, we found that ethylene is required for the full expression of RIN and several RIN-targeting transcription factor genes at the ripening stage. Here, based on our recently published findings and additional data, we discuss the ripening processes regulated by RIN and the interplay between RIN and ethylene. PMID:23518588

  9. Potent selective nonpeptidic inhibitors of human lung tryptase

    Science.gov (United States)

    Burgess, Laurence E.; Newhouse, Bradley J.; Ibrahim, Prabha; Rizzi, James; Kashem, Mohammed A.; Hartman, Ann; Brandhuber, Barbara J.; Wright, Clifford D.; Thomson, David S.; Vigers, Guy P. A.; Koch, Kevin

    1999-01-01

    Human lung tryptase, a homotetrameric serine protease unique to mast cell secretory granules, has been implicated in the pathogenesis of asthma. A hypothesis that tethered symmetrical inhibitors might bridge two adjacent active sites was explored via a rationally designed series of bisbenzamidines. These compounds demonstrated a remarkable distanced-defined structure–activity relationship against human tryptase with one series possessing subnanomolar potencies. Additional evidence supporting the concept of active-site bridging is also presented. PMID:10411878

  10. Discovering Bisdemethoxycurcumin from Curcuma longa rhizome as a potent small molecule inhibitor of human pancreatic α-amylase, a target for type-2 diabetes.

    Science.gov (United States)

    Ponnusamy, Sudha; Zinjarde, Smita; Bhargava, Shobha; Rajamohanan, P R; Ravikumar, Ameeta

    2012-12-15

    Curcuma longa rhizome is used extensively in culinary preparations in Far East and South-East Asia. Health benefits of curcuminoids from C. longa as antioxidants, anti-cancer and anti-inflammatory molecules have been well documented. We report here for the first time that Bisdemethoxycurcumin (BDMC) from C. longa, acts as an inhibitor to inactivate human pancreatic α-amylase, a therapeutic target for oral hypoglycemic agents in type-2 diabetes. Bioactivity guided isolation of rhizome isopropanol extract led to the identification by HPLC and NMR of BDMC as a lead small molecule inhibitor of porcine and human pancreatic α-amylase with an IC(50) value of 0.026 and 0.025 mM, respectively. Kinetic analysis revealed that using starch as the substrate, HPA exhibited an uncompetitive mode of inhibition with an apparent K(i) of 3.0 μM. The study gains importance as BDMC could be a good drug candidate in development of new inhibitors of HPA and of functional foods for controlling starch digestion in order to reduce post-prandial hyperglycemia. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Approved and Experimental Small-Molecule Oncology Kinase Inhibitor Drugs: A Mid-2016 Overview.

    Science.gov (United States)

    Fischer, Peter M

    2017-03-01

    Kinase inhibitor research is a comparatively recent branch of medicinal chemistry and pharmacology and the first small-molecule kinase inhibitor, imatinib, was approved for clinical use only 15 years ago. Since then, 33 more kinase inhibitor drugs have received regulatory approval for the treatment of a variety of cancers and the volume of reports on the discovery and development of kinase inhibitors has increased to an extent where it is now difficult-even for those working in the field-easily to keep an overview of the compounds that are being developed, as currently there are 231 such compounds, targeting 38 different protein and lipid kinases (not counting isoforms), in clinical use or under clinical investigation. The purpose of this review is thus to provide an overview of the biomedical rationales for the kinases being targeted on the one hand, and the design principles, as well as chemical, pharmacological, pharmaceutical, and toxicological kinase inhibitor properties, on the other hand. Two issues that are especially important in kinase inhibitor research, target selectivity and drug resistance, as well as the underlying structural concepts, are discussed in general terms and in the context of relevant kinases and their inhibitors. © 2016 Wiley Periodicals, Inc.

  12. HPPD: ligand- and target-based virtual screening on a herbicide target.

    Science.gov (United States)

    López-Ramos, Miriam; Perruccio, Francesca

    2010-05-24

    Hydroxyphenylpyruvate dioxygenase (HPPD) has proven to be a very successful target for the development of herbicides with bleaching properties, and today HPPD inhibitors are well established in the agrochemical market. Syngenta has a long history of HPPD-inhibitor research, and HPPD was chosen as a case study for the validation of diverse ligand- and target-based virtual screening approaches to identify compounds with inhibitory properties. Two-dimensional extended connectivity fingerprints, three-dimensional shape-based tools (ROCS, EON, and Phase-shape) and a pharmacophore approach (Phase) were used as ligand-based methods; Glide and Gold were used as target-based. Both the virtual screening utility and the scaffold-hopping ability of the screening tools were assessed. Particular emphasis was put on the specific pitfalls to take into account for the design of a virtual screening campaign in an agrochemical context, as compared to a pharmaceutical environment.

  13. Tofacitinib and analogs as inhibitors of the histone kinase PRK1 (PKN1).

    Science.gov (United States)

    Ostrovskyi, Dmytro; Rumpf, Tobias; Eib, Julia; Lumbroso, Alexandre; Slynko, Inna; Klaeger, Susan; Heinzlmeir, Stephanie; Forster, Michael; Gehringer, Matthias; Pfaffenrot, Ellen; Bauer, Silke Mona; Schmidtkunz, Karin; Wenzler, Sandra; Metzger, Eric; Kuster, Bernhard; Laufer, Stefan; Schüle, Roland; Sippl, Wolfgang; Breit, Bernhard; Jung, Manfred

    2016-09-01

    The histone kinase PRK1 has been identified as a potential target to combat prostate cancer but selective PRK1 inhibitors are lacking. The US FDA -approved JAK1-3 inhibitor tofacitinib also potently inhibits PRK1 in vitro. We show that tofacitinib also inhibits PRK1 in a cellular setting. Using tofacitinib as a starting point for structure-activity relationship studies, we identified a more potent and another more selective PRK1 inhibitor compared with tofacitinib. Furthermore, we found two potential PRK1/JAK3-selectivity hotspots. The identified inhibitors and the selectivity hotspots lay the basis for the development of selective PRK1 inhibitors. The identification of PRK1, but also of other cellular tofacitinib targets, has implications on its clinical use and on future development of tofacitinib-like JAK inhibitors. [Formula: see text].

  14. A screen for kinase inhibitors identifies antimicrobial imidazopyridine aminofurazans as specific inhibitors of the Listeria monocytogenes PASTA kinase PrkA.

    Science.gov (United States)

    Schaenzer, Adam J; Wlodarchak, Nathan; Drewry, David H; Zuercher, William J; Rose, Warren E; Striker, Rob; Sauer, John-Demian

    2017-10-13

    Bacterial signaling systems such as protein kinases and quorum sensing have become increasingly attractive targets for the development of novel antimicrobial agents in a time of rising antibiotic resistance. The family of bacterial P enicillin-binding-protein A nd S erine/ T hreonine kinase- A ssociated (PASTA) kinases is of particular interest due to the role of these kinases in regulating resistance to β-lactam antibiotics. As such, small-molecule kinase inhibitors that target PASTA kinases may prove beneficial as treatments adjunctive to β-lactam therapy. Despite this interest, only limited progress has been made in identifying functional inhibitors of the PASTA kinases that have both activity against the intact microbe and high kinase specificity. Here, we report the results of a small-molecule screen that identified GSK690693, an imidazopyridine aminofurazan-type kinase inhibitor that increases the sensitivity of the intracellular pathogen Listeria monocytogenes to various β-lactams by inhibiting the PASTA kinase PrkA. GSK690693 potently inhibited PrkA kinase activity biochemically and exhibited significant selectivity for PrkA relative to the Staphylococcus aureus PASTA kinase Stk1. Furthermore, other imidazopyridine aminofurazans could effectively inhibit PrkA and potentiate β-lactam antibiotic activity to varying degrees. The presence of the 2-methyl-3-butyn-2-ol (alkynol) moiety was important for both biochemical and antimicrobial activity. Finally, mutagenesis studies demonstrated residues in the back pocket of the active site are important for GSK690693 selectivity. These data suggest that targeted screens can successfully identify PASTA kinase inhibitors with both biochemical and antimicrobial specificity. Moreover, the imidazopyridine aminofurazans represent a family of PASTA kinase inhibitors that have the potential to be optimized for selective PASTA kinase inhibition.

  15. SGLT2 inhibitors.

    Science.gov (United States)

    Dardi, I; Kouvatsos, T; Jabbour, S A

    2016-02-01

    Diabetes mellitus is a serious health issue and an economic burden, rising in epidemic proportions over the last few decades worldwide. Although several treatment options are available, only half of the global diabetic population achieves the recommended or individualized glycemic targets. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of antidiabetic agents with a novel insulin-independent action. SGLT2 is a transporter found in the proximal renal tubules, responsible for the reabsorption of most of the glucose filtered by the kidney. Inhibition of SGLT2 lowers the blood glucose level by promoting the urinary excretion of excess glucose. Due to their insulin-independent action, SGLT2 inhibitors can be used with any degree of beta-cell dysfunction or insulin resistance, related to a very low risk of hypoglycemia. In addition to improving glycemic control, SGLT2 inhibitors have been associated with a reduction in weight and blood pressure when used as monotherapy or in combination with other antidiabetic agents in patients with type 2 diabetes mellitus (T2DM). Treatment with SGLT2 inhibitors is usually well tolerated; however, they have been associated with an increased incidence of urinary tract and genital infections, although these infections are usually mild and easy to treat. SGLT2 inhibitors are a promising new option in the armamentarium of drugs for patients with T2DM. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Prevalence and natural history of ALK positive non-small-cell lung cancer and the clinical impact of targeted therapy with ALK inhibitors

    Directory of Open Access Journals (Sweden)

    Chia PL

    2014-11-01

    Full Text Available Puey Ling Chia,1 Paul Mitchell,1 Alexander Dobrovic,2–4 Thomas John1,2,4 1Department of Medical Oncology, Olivia-Newton John Cancer and Wellness Centre, Victoria, Australia; 2Ludwig Institute for Cancer Research, Austin Health, Victoria, Australia; 3Department of Pathology, University of Melbourne, Victoria, Australia; 4School of Cancer Medicine, La Trobe University, Victoria, Australia Abstract: Improved understanding of molecular drivers of carcinogenesis has led to significant progress in the management of lung cancer. Patients with non-small-cell lung cancer (NSCLC with anaplastic lymphoma kinase (ALK gene rearrangements constitute about 4%–5% of all NSCLC patients. ALK+ NSCLC cells respond well to small molecule ALK inhibitors such as crizotinib; however, resistance invariably develops after several months of treatment. There are now several newer ALK inhibitors, with the next generation of agents targeting resistance mutations. In this review, we will discuss the prevalence and clinical characteristics of ALK+ lung cancer, current treatment options, and future directions in the management of this subset of NSCLC patients. Keywords: anaplastic lymphoma kinase (ALK, gene rearrangements, lung cancer, kinase inhibitors, lung adenocarcinoma

  17. ERK mutations confer resistance to mitogen-activated protein kinase pathway inhibitors.

    Science.gov (United States)

    Goetz, Eva M; Ghandi, Mahmoud; Treacy, Daniel J; Wagle, Nikhil; Garraway, Levi A

    2014-12-01

    The use of targeted therapeutics directed against BRAF(V600)-mutant metastatic melanoma improves progression-free survival in many patients; however, acquired drug resistance remains a major medical challenge. By far, the most common clinical resistance mechanism involves reactivation of the MAPK (RAF/MEK/ERK) pathway by a variety of mechanisms. Thus, targeting ERK itself has emerged as an attractive therapeutic concept, and several ERK inhibitors have entered clinical trials. We sought to preemptively determine mutations in ERK1/2 that confer resistance to either ERK inhibitors or combined RAF/MEK inhibition in BRAF(V600)-mutant melanoma. Using a random mutagenesis screen, we identified multiple point mutations in ERK1 (MAPK3) and ERK2 (MAPK1) that could confer resistance to ERK or RAF/MEK inhibitors. ERK inhibitor-resistant alleles were sensitive to RAF/MEK inhibitors and vice versa, suggesting that the future development of alternating RAF/MEK and ERK inhibitor regimens might help circumvent resistance to these agents. ©2014 American Association for Cancer Research.

  18. JAK inhibitors in autoinflammation.

    Science.gov (United States)

    Hoffman, Hal M; Broderick, Lori

    2018-06-11

    Interferonopathies are a subset of autoinflammatory disorders with a prominent type I IFN gene signature. Treatment of these patients has been challenging, given the lack of response to common autoinflammatory therapeutics including IL-1 and TNF blockade. JAK inhibitors (Jakinibs) are a family of small-molecule inhibitors that target the JAK/STAT signaling pathway and have shown clinical efficacy, with FDA and European Medicines Agency (EMA) approval for arthritic and myeloproliferative syndromes. Sanchez and colleagues repurposed baricitinib to establish a significant role for JAK inhibition as a novel therapy for patients with interferonopathies, demonstrating the power of translational rare disease research with lifesaving effects.

  19. Inhibition of TLR2 signaling by small molecule inhibitors targeting a pocket within the TLR2 TIR domain

    Science.gov (United States)

    Mistry, Pragnesh; Laird, Michelle H. W.; Schwarz, Ryan S.; Greene, Shannon; Dyson, Tristan; Snyder, Greg A.; Xiao, Tsan Sam; Chauhan, Jay; Fletcher, Steven; Toshchakov, Vladimir Y.; MacKerell, Alexander D.; Vogel, Stefanie N.

    2015-01-01

    Toll-like receptor (TLR) signaling is initiated by dimerization of intracellular Toll/IL-1 receptor resistance (TIR) domains. For all TLRs except TLR3, recruitment of the adapter, myeloid differentiation primary response gene 88 (MyD88), to TLR TIR domains results in downstream signaling culminating in proinflammatory cytokine production. Therefore, blocking TLR TIR dimerization may ameliorate TLR2-mediated hyperinflammatory states. The BB loop within the TLR TIR domain is critical for mediating certain protein–protein interactions. Examination of the human TLR2 TIR domain crystal structure revealed a pocket adjacent to the highly conserved P681 and G682 BB loop residues. Using computer-aided drug design (CADD), we sought to identify a small molecule inhibitor(s) that would fit within this pocket and potentially disrupt TLR2 signaling. In silico screening identified 149 compounds and 20 US Food and Drug Administration-approved drugs based on their predicted ability to bind in the BB loop pocket. These compounds were screened in HEK293T-TLR2 transfectants for the ability to inhibit TLR2-mediated IL-8 mRNA. C16H15NO4 (C29) was identified as a potential TLR2 inhibitor. C29, and its derivative, ortho-vanillin (o-vanillin), inhibited TLR2/1 and TLR2/6 signaling induced by synthetic and bacterial TLR2 agonists in human HEK-TLR2 and THP-1 cells, but only TLR2/1 signaling in murine macrophages. C29 failed to inhibit signaling induced by other TLR agonists and TNF-α. Mutagenesis of BB loop pocket residues revealed an indispensable role for TLR2/1, but not TLR2/6, signaling, suggesting divergent roles. Mice treated with o-vanillin exhibited reduced TLR2-induced inflammation. Our data provide proof of principle that targeting the BB loop pocket is an effective approach for identification of TLR2 signaling inhibitors. PMID:25870276

  20. The 'retro-design' concept for novel kinase inhibitors.

    Science.gov (United States)

    Müller, Gerhard; Sennhenn, Peter C; Woodcock, Timothy; Neumann, Lars

    2010-07-01

    Protein kinases are among the most attractive therapeutic targets for a broad range of diseases. This feature review highlights and classifies the main design principles employed to generate active and selective kinase inhibitors. In particular, emphasis is focused on a fragment-based lead-generation approach, which constitutes a novel design method for developing type II kinase inhibitors with distinct binding kinetic attributes. This 'retro-design' strategy relies on a customized fragment library, and contrasts the traditional approach used in the design of type II inhibitors.

  1. Synthesis, pharmacology and molecular docking on multifunctional tacrine-ferulic acid hybrids as cholinesterase inhibitors against Alzheimer's disease.

    Science.gov (United States)

    Zhu, Jie; Yang, Hongyu; Chen, Yao; Lin, Hongzhi; Li, Qi; Mo, Jun; Bian, Yaoyao; Pei, Yuqiong; Sun, Haopeng

    2018-12-01

    The cholinergic hypothesis has long been a "polar star" in drug discovery for Alzheimer's disease (AD), resulting in many small molecules and biological drug candidates. Most of the drugs marketed for AD are cholinergic. Herein, we report our efforts in the discovery of cholinesterases inhibitors (ChEIs) as multi-target-directed ligands. A series of tacrine-ferulic acid hybrids have been designed and synthesised. All these compounds showed potent acetyl-(AChE) and butyryl cholinesterase(BuChE) inhibition. Among them, the optimal compound 10g, was the most potent inhibitor against AChE (electrophorus electricus (eeAChE) half maximal inhibitory concentration (IC 50 ) = 37.02 nM), it was also a strong inhibitor against BuChE (equine serum (eqBuChE) IC 50  = 101.40 nM). Besides, it inhibited amyloid β-protein self-aggregation by 65.49% at 25 μM. In subsequent in vivo scopolamine-induced AD models, compound 10g obviously ameliorated the cognition impairment and showed preliminary safety in hepatotoxicity evaluation. These data suggest compound 10g as a promising multifunctional agent in the drug discovery process against AD.

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

    Science.gov (United States)

    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

  3. Synergistic apoptosis induction in leukemic cells by the phosphatase inhibitor salubrinal and proteasome inhibitors.

    Directory of Open Access Journals (Sweden)

    Hannes C A Drexler

    Full Text Available Cells adapt to endoplasmic reticulum (ER-stress by arresting global protein synthesis while simultaneously activating specific transcription factors and their downstream targets. These processes are mediated in part by the phosphorylation-dependent inactivation of the translation initiation factor eIF2alpha. Following restoration of homeostasis protein synthesis is resumed when the serine/threonine-protein phosphatase PP1 dephosphorylates and reactivates eIF2alpha. Proteasome inhibitors, used to treat multiple myeloma patients evoke ER-stress and apoptosis by blocking the ER-associated degradation of misfolded proteins (ERAD, however, the role of eIF2alpha phosphorylation in leukemic cells under conditions of proteasome inhibitor-mediated ER stress is currently unclear.Bcr-Abl-positive and negative leukemic cell lines were used to investigate the functional implications of PP1-related phosphatase activities on eIF2alpha phosphorylation in proteasome inhibitor-mediated ER stress and apoptosis. Rather unexpectedly, salubrinal, a recently identified PP1 inhibitor capable to protect against ER stress in various model systems, strongly synergized with proteasome inhibitors to augment apoptotic death of different leukemic cell lines. Salubrinal treatment did not affect the phosphorlyation status of eIF2alpha. Furthermore, the proapoptotic effect of salubrinal occurred independently from the chemical nature of the proteasome inhibitor, was recapitulated by a second unrelated phosphatase inhibitor and was unaffected by overexpression of a dominant negative eIF2alpha S51A variant that can not be phosphorylated. Salubrinal further aggravated ER-stress and proteotoxicity inflicted by the proteasome inhibitors on the leukemic cells since characteristic ER stress responses, such as ATF4 and CHOP synthesis, XBP1 splicing, activation of MAP kinases and eventually apoptosis were efficiently abrogated by the translational inhibitor cycloheximide.Although PP1

  4. The TosMIC approach to 3-(oxazol-5-yl) indoles: application to the synthesis of indole-based IMPDH inhibitors.

    Science.gov (United States)

    Dhar, T G Murali; Shen, Zhongqi; Fleener, Catherine A; Rouleau, Katherine A; Barrish, Joel C; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2002-11-18

    A modified approach to the synthesis of 3-(oxazolyl-5-yl) indoles is reported. This method was applied to the synthesis of series of novel indole based inhibitors of inosine monophosphate dehydrogenase (IMPDH). The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for this new series of inhibitors is given.

  5. Development of multifunctional, heterodimeric isoindoline-1,3-dione derivatives as cholinesterase and β-amyloid aggregation inhibitors with neuroprotective properties.

    Science.gov (United States)

    Guzior, Natalia; Bajda, Marek; Skrok, Mirosław; Kurpiewska, Katarzyna; Lewiński, Krzysztof; Brus, Boris; Pišlar, Anja; Kos, Janko; Gobec, Stanislav; Malawska, Barbara

    2015-03-06

    The presented study describes the synthesis, pharmacological evaluation (AChE and BuChE inhibition, beta amyloid anti-aggregation effect and neuroprotective effect), molecular modeling and crystallographic studies of a novel series of isoindoline-1,3-dione derivatives. The target compounds were designed as dual binding site acetylcholinesterase inhibitors with an arylalkylamine moiety binding at the catalytic site of the enzyme and connected via an alkyl chain to a heterocyclic fragment, capable of binding at the peripheral anionic site of AChE. Among these molecules, compound 15b was found to be the most potent and selective AChE inhibitor (IC50EeAChE = 0.034 μM). Moreover, compound 13b in addition to AChE inhibition (IC50 EeAChE = 0.219 μM) possesses additional properties, such as the ability to inhibit Aβ aggregation (65.96% at 10 μM) and a neuroprotective effect against Aβ toxicity at 1 and 3 μM. Compound 13b emerges as a promising multi-target ligand for the further development of the therapy for age-related neurodegenerative disorders. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  6. MEK Inhibitors Reverse cAMP-Mediated Anxiety in Zebrafish

    DEFF Research Database (Denmark)

    Lundegaard, Pia R.; Anastasaki, Corina; Grant, Nicola J.

    2015-01-01

    Altered phosphodiesterase (PDE)-cyclic AMP (cAMP) activity is frequently associated with anxiety disorders, but current therapies act by reducing neuronal excitability rather than targeting PDE-cAMP-mediated signaling pathways. Here, we report the novel repositioning of anti-cancer MEK inhibitors...... as anxiolytics in a zebrafish model of anxiety-like behaviors. PDE inhibitors or activators of adenylate cyclase cause behaviors consistent with anxiety in larvae and adult zebrafish. Small-molecule screening identifies MEK inhibitors as potent suppressors of cAMP anxiety behaviors in both larvae and adult...... zebrafish, while causing no anxiolytic behavioral effects on their own. The mechanism underlying cAMP-induced anxiety is via crosstalk to activation of the RAS-MAPK signaling pathway. We propose that targeting crosstalk signaling pathways can be an effective strategy for mental health disorders, and advance...

  7. ESCMID Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biological therapies: an infectious diseases perspective (Intracellular signaling pathways: tyrosine kinase and mTOR inhibitors).

    Science.gov (United States)

    Reinwald, M; Silva, J T; Mueller, N J; Fortún, J; Garzoni, C; de Fijter, J W; Fernández-Ruiz, M; Grossi, P; Aguado, J M

    2018-06-01

    The present review is part of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Infections in Compromised Hosts (ESGICH) Consensus Document on the safety of targeted and biologic therapies. To review, from an infectious diseases perspective, the safety profile of therapies targeting different intracellular signaling pathways and to suggest preventive recommendations. Computer-based Medline searches with MeSH terms pertaining to each agent or therapeutic family. Although BCR-ABL tyrosine kinase inhibitors modestly increase the overall risk of infection, dasatinib has been associated with cytomegalovirus and hepatitis B virus reactivation. BRAF/MEK kinase inhibitors do not significantly affect infection susceptibility. The effect of Bruton tyrosine kinase inhibitors (ibrutinib) among patients with B-cell malignancies is difficult to distinguish from that of previous immunosuppression. However, cases of Pneumocystis jirovecii pneumonia (PCP), invasive fungal infection and progressive multifocal leukoencephalopathy have been occasionally reported. Because phosphatidylinositol-3-kinase inhibitors (idelalisib) may predispose to opportunistic infections, anti-Pneumocystis prophylaxis and prevention strategies for cytomegalovirus are recommended. No increased rates of infection have been observed with venetoclax (antiapoptotic protein Bcl-2 inhibitor). Therapy with Janus kinase inhibitors markedly increases the incidence of infection. Pretreatment screening for chronic hepatitis B virus and latent tuberculosis infection must be performed, and anti-Pneumocystis prophylaxis should be considered for patients with additional risk factors. Cancer patients receiving mTOR inhibitors face an increased incidence of overall infection, especially those with additional risk factors (prior therapies or delayed wound healing). Specific preventive approaches are warranted in view of the increased risk of infection associated with some of the

  8. Virtual screening for potential inhibitors of bacterial MurC and MurD ligases.

    Science.gov (United States)

    Tomašić, Tihomir; Kovač, Andreja; Klebe, Gerhard; Blanot, Didier; Gobec, Stanislav; Kikelj, Danijel; Mašič, Lucija Peterlin

    2012-03-01

    Mur ligases are bacterial enzymes involved in the cytoplasmic steps of peptidoglycan biosynthesis and are viable targets for antibacterial drug discovery. We have performed virtual screening for potential ATP-competitive inhibitors targeting MurC and MurD ligases, using a protocol of consecutive hierarchical filters. Selected compounds were evaluated for inhibition of MurC and MurD ligases, and weak inhibitors possessing dual inhibitory activity have been identified. These compounds represent new scaffolds for further optimisation towards multiple Mur ligase inhibitors with improved inhibitory potency.

  9. Combining RNA interference and kinase inhibitors against cell signalling components involved in cancer

    International Nuclear Information System (INIS)

    O'Grady, Michael; Raha, Debasish; Hanson, Bonnie J; Bunting, Michaeline; Hanson, George T

    2005-01-01

    The transcription factor activator protein-1 (AP-1) has been implicated in a large variety of biological processes including oncogenic transformation. The tyrosine kinases of the epidermal growth factor receptor (EGFR) constitute the beginning of one signal transduction cascade leading to AP-1 activation and are known to control cell proliferation and differentiation. Drug discovery efforts targeting this receptor and other pathway components have centred on monoclonal antibodies and small molecule inhibitors. Resistance to such inhibitors has already been observed, guiding the prediction of their use in combination therapies with other targeted agents such as RNA interference (RNAi). This study examines the use of RNAi and kinase inhibitors for qualification of components involved in the EGFR/AP-1 pathway of ME180 cells, and their inhibitory effects when evaluated individually or in tandem against multiple components of this important disease-related pathway. AP-1 activation was assessed using an ME180 cell line stably transfected with a beta-lactamase reporter gene under the control of AP-1 response element following epidermal growth factor (EGF) stimulation. Immunocytochemistry allowed for further quantification of small molecule inhibition on a cellular protein level. RNAi and RT-qPCR experiments were performed to assess the amount of knockdown on an mRNA level, and immunocytochemistry was used to reveal cellular protein levels for the targeted pathway components. Increased potency of kinase inhibitors was shown by combining RNAi directed towards EGFR and small molecule inhibitors acting at proximal or distal points in the pathway. After cellular stimulation with EGF and analysis at the level of AP-1 activation using a β-lactamase reporter gene, a 10–12 fold shift or 2.5–3 fold shift toward greater potency in the IC 50 was observed for EGFR and MEK-1 inhibitors, respectively, in the presence of RNAi targeting EGFR. EGFR pathway components were qualified as

  10. Kinase inhibitors: a new class of antirheumatic drugs

    Directory of Open Access Journals (Sweden)

    Kyttaris VC

    2012-09-01

    Full Text Available Vasileios C KyttarisDivision of Rheumatology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USAAbstract: The outlook for patients with rheumatoid arthritis has improved significantly over the last three decades with the use of disease-modifying antirheumatic drugs. However, despite the use of methotrexate, cytokine inhibitors, and molecules targeting T and B cells, a percentage of patients do not respond or lose their response over time. The autoimmune process in rheumatoid arthritis depends on activation of immune cells, which utilize intracellular kinases to respond to external stimuli such as cytokines, immune complexes, and antigens. In the past decade, small molecules targeting several kinases, such as p38 MAPK, Syk, and JAK have been developed. Several p38 MAPK inhibitors proved ineffective in treating rheumatoid arthritis. The Syk inhibitor, fostamatinib, proved superior to placebo in Phase II trials and is currently under Phase III investigation. Tofacitinib, a JAK1/3 inhibitor, was shown to be efficacious in two Phase III trials, while VX-509, a JAK3 inhibitor, showed promising results in a Phase II trial. Fostamatinib and tofacitinib were associated with increased rates of infection, elevation of liver enzymes, and neutropenia. Moreover, fostamatinib caused elevations of blood pressure and diarrhea, while tofacitinib was associated with an increase in creatinine and elevation of lipid levels.Keywords: rheumatoid arthritis, kinase inhibitors, mitogen-activated phosphokinase p38, spleen tyrosine kinase, Janus kinases

  11. Evaluation of a series of 2-napthamide derivatives as inhibitors of the drug efflux pump AcrB for the reversal of antimicrobial resistance.

    Science.gov (United States)

    Wang, Yinhu; Mowla, Rumana; Guo, Liwei; Ogunniyi, Abiodun D; Rahman, Taufiq; De Barros Lopes, Miguel A; Ma, Shutao; Venter, Henrietta

    2017-02-15

    Drug efflux pumps confer multidrug resistance to dangerous pathogens which makes these pumps important drug targets. We have synthesised a novel series of compounds based on a 2-naphthamide pharmacore aimed at inhibiting the efflux pumps from Gram-negative bacteria. The archeatypical transporter AcrB from Escherichia coli was used as model efflux pump as AcrB is widely conserved throughout Gram-negative organisms. The compounds were tested for their antibacterial action, ability to potentiate the action of antibiotics and for their ability to inhibit Nile Red efflux by AcrB. None of the compounds were antimicrobial against E. coli wild type cells. Most of the compounds were able to inhibit Nile Red efflux indicating that they are substrates of the AcrB efflux pump. Three compounds were able to synergise with antibiotics and reverse resistance in the resistant phenotype. Compound A3, 4-(isopentyloxy)-2-naphthamide, reduced the MICs of erythromycin and chloramphenicol to the MIC levels of the drug sensitive strain that lacks an efflux pump. A3 had no effect on the MIC of the non-substrate rifampicin indicating that this compound acts specifically through the AcrB efflux pump. A3 also does not act through non-specific mechanisms such as outer membrane or inner membrane permeabilisation and is not cytotoxic against mammalian cell lines. Therefore, we have designed and synthesised a novel chemical compound with great potential to further optimisation as inhibitor of drug efflux pumps. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  13. Clinical Pharmacology of Kinase Inhibitors in Oncology : Personalized and Optimzed Dosing

    NARCIS (Netherlands)

    Verheijen, Remy B.

    2017-01-01

    Kinase inhibitors are an important category of molecularly targeted therapies used for cancer. Verheijen’s doctoral thesis describes several clinical pharmacological studies to optimize and personalize the treatment of cancer with kinase inhibitors, using pharmacokinetics, molecular imaging and

  14. Design, Synthesis and Biological Evaluation of Novel Benzothiazole Derivatives as Selective PI3Kβ Inhibitors

    Directory of Open Access Journals (Sweden)

    Shuang Cao

    2016-07-01

    Full Text Available A novel series of PI3Kβ (Phosphatidylinositol-3-kinases beta subunit inhibitors with the structure of benzothiazole scaffold have been designed and synthesized. All the compounds have been evaluated for inhibitory activities against PI3Kα, β, γ, δ and mTOR (Mammalian target of rapamycin. Two superior compounds have been further evaluated for the IC50 values against PI3Ks/mTOR. The most promising compound 11 displays excellent anti-proliferative activity and selectivity in multiple cancer cell lines, especially in the prostate cancer cell line. Docking studies indicate the morpholine group in 2-position of benzothiazole is necessary for the potent antitumor activity, which confirms our design is reasonable.

  15. Protease Inhibitors of Parasitic Flukes: Emerging Roles in Parasite Survival and Immune Defence.

    Science.gov (United States)

    Ranasinghe, Shiwanthi L; McManus, Donald P

    2017-05-01

    Protease inhibitors play crucial roles in parasite development and survival, counteracting the potentially damaging immune responses of their vertebrate hosts. However, limited information is currently available on protease inhibitors from schistosomes and food-borne trematodes. Future characterization of these molecules is important not only to expand knowledge on parasitic fluke biology but also to determine whether they represent novel vaccine and/or drug targets. Moreover, protease inhibitors from flukes may represent lead compounds for the development of a new range of therapeutic agents against inflammatory disorders and cancer. This review discusses already identified protease inhibitors of fluke origin, emphasizing their biological function and their possible future development as new intervention targets. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. BTK inhibitors in chronic lymphocytic leukemia: a glimpse to the future

    NARCIS (Netherlands)

    Spaargaren, M.; de Rooij, M. F. M.; Kater, A. P.; Eldering, E.

    2015-01-01

    The treatment of chronic lymphocytic leukemia (CLL) with inhibitors targeting B cell receptor signaling and other survival mechanisms holds great promise. Especially the early clinical success of Ibrutinib, an irreversible inhibitor of Bruton's tyrosine kinase (BTK), has received widespread

  17. Perturbation biology nominates upstream–downstream drug combinations in RAF inhibitor resistant melanoma cells

    Science.gov (United States)

    Korkut, Anil; Wang, Weiqing; Demir, Emek; Aksoy, Bülent Arman; Jing, Xiaohong; Molinelli, Evan J; Babur, Özgün; Bemis, Debra L; Onur Sumer, Selcuk; Solit, David B; Pratilas, Christine A; Sander, Chris

    2015-01-01

    Resistance to targeted cancer therapies is an important clinical problem. The discovery of anti-resistance drug combinations is challenging as resistance can arise by diverse escape mechanisms. To address this challenge, we improved and applied the experimental-computational perturbation biology method. Using statistical inference, we build network models from high-throughput measurements of molecular and phenotypic responses to combinatorial targeted perturbations. The models are computationally executed to predict the effects of thousands of untested perturbations. In RAF-inhibitor resistant melanoma cells, we measured 143 proteomic/phenotypic entities under 89 perturbation conditions and predicted c-Myc as an effective therapeutic co-target with BRAF or MEK. Experiments using the BET bromodomain inhibitor JQ1 affecting the level of c-Myc protein and protein kinase inhibitors targeting the ERK pathway confirmed the prediction. In conclusion, we propose an anti-cancer strategy of co-targeting a specific upstream alteration and a general downstream point of vulnerability to prevent or overcome resistance to targeted drugs. DOI: http://dx.doi.org/10.7554/eLife.04640.001 PMID:26284497

  18. The discovery of novel tartrate-based TNF-[alpha] converting enzyme (TACE) inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Rosner, Kristin E.; Guo, Zhuyan; Orth, Peter; Shipps, Jr., Gerald W.; Belanger, David B.; Chan, Tin Yau; Curran, Patrick J.; Dai, Chaoyang; Deng, Yongqi; Girijavallabhan, Vinay M.; Hong, Liwu; Lavey, Brian J.; Lee, Joe F.; Li, Dansu; Liu, Zhidan; Popovici-Muller, Janeta; Ting, Pauline C.; Vaccaro, Henry; Wang, Li; Wang, Tong; Yu, W.; Zhou, G.; Niu, X.; Sun, J.; Kozlowski, J.A.; Lundell, D.J.; Madison, V.; McKittrick, B.; Piwinski, J.J.; Shih, N.Y.; Siddiqui, M. Arshad; Strickland, Corey O. (SPRI)

    2010-09-17

    A novel series of TNF-{alpha} convertase (TACE) inhibitors which are non-hydroxamate have been discovered. These compounds are bis-amides of L-tartaric acid (tartrate) and coordinate to the active site zinc in a tridentate manner. They are selective for TACE over other MMP's. We report the first X-ray crystal structure for a tartrate-based TACE inhibitor.

  19. Discovery of Selective Phosphodiesterase 1 Inhibitors with Memory Enhancing Properties.

    Science.gov (United States)

    Dyck, Brian; Branstetter, Bryan; Gharbaoui, Tawfik; Hudson, Andrew R; Breitenbucher, J Guy; Gomez, Laurent; Botrous, Iriny; Marrone, Tami; Barido, Richard; Allerston, Charles K; Cedervall, E Peder; Xu, Rui; Sridhar, Vandana; Barker, Ryan; Aertgeerts, Kathleen; Schmelzer, Kara; Neul, David; Lee, Dong; Massari, Mark Eben; Andersen, Carsten B; Sebring, Kristen; Zhou, Xianbo; Petroski, Robert; Limberis, James; Augustin, Martin; Chun, Lawrence E; Edwards, Thomas E; Peters, Marco; Tabatabaei, Ali

    2017-04-27

    A series of potent thienotriazolopyrimidinone-based PDE1 inhibitors was discovered. X-ray crystal structures of example compounds from this series in complex with the catalytic domain of PDE1B and PDE10A were determined, allowing optimization of PDE1B potency and PDE selectivity. Reduction of hERG affinity led to greater than a 3000-fold selectivity for PDE1B over hERG. 6-(4-Methoxybenzyl)-9-((tetrahydro-2H-pyran-4-yl)methyl)-8,9,10,11-tetrahydropyrido[4',3':4,5]thieno[3,2-e][1,2,4]triazolo[1,5-c]pyrimidin-5(6H)-one was identified as an orally bioavailable and brain penetrating PDE1B enzyme inhibitor with potent memory-enhancing effects in a rat model of object recognition memory.

  20. Structural Biology Insight for the Design of Sub-type Selective Aurora Kinase Inhibitors.

    Science.gov (United States)

    Sarvagalla, Sailu; Coumar, Mohane Selvaraj

    2015-01-01

    Aurora kinase A, B and C, are key regulators of mitosis and are over expressed in many of the human cancers, making them an ideal drug target for cancer chemotherapy. Currently, over a dozen of Aurora kinase inhibitors are in various phases of clinical development. The majority of the inhibitors (VX-680/MK-0457, PHA-739358, CYC116, SNS-314, AMG 900, AT-9283, SCH- 1473759, ABT-348, PF-03814735, R-763/AS-703569, KW-2449 and TAK-901) are pan-selective (isoform non-selective) and few are Aurora A (MLN8054, MLN8237, VX-689/MK5108 and ENMD 2076) and Aurora B (AZD1152 and GSK1070916) sub-type selective. Despite the intensive research efforts in the past decade, no Aurora kinase inhibitor has reached the market. Recent evidence suggests that the sub-type selective Aurora kinase A inhibitor could possess advantages over pan-selective Aurora inhibitors, by avoiding Aurora B mediated neutropenia. However, sub-type selective Aurora kinase A inhibitor design is very challenging due to the similarity in the active site among the isoforms. Structural biology and computational aspects pertaining to the design of Aurora kinase inhibitors were analyzed and found that a possible means to develop sub-type selective inhibitor is by targeting Aurora A specific residues (Leu215, Thr217 and Arg220) or Aurora B specific residues (Arg159, Glu161 and Lys164), near the solvent exposed region of the protein. Particularly, a useful strategy for the design of sub-type selective Aurora A inhibitor could be by targeting Thr217 residue as in the case of MLN8054. Further preclinical and clinical studies with the sub-type selective Aurora inhibitors could help bring them to the market for the treatment of cancer.

  1. Urea transporter proteins as targets for small-molecule diuretics.

    Science.gov (United States)

    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.

  2. Discovery of potent and selective CDK8 inhibitors through FBDD approach.

    Science.gov (United States)

    Han, Xingchun; Jiang, Min; Zhou, Chengang; Zhou, Zheng; Xu, Zhiheng; Wang, Lisha; Mayweg, Alexander V; Niu, Rui; Jin, Tai-Guang; Yang, Song

    2017-09-15

    A fragment library screen was carried out to identify starting points for novel CDK8 inhibitors. Optimization of a fragment hit guided by co-crystal structures led to identification of a novel series of potent CDK8 inhibitors which are highly ligand efficient, kinase selective and cellular active. Compound 16 was progressed to a mouse pharmacokinetic study and showed good oral bioavailability. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Discovery of a new chemical series of BRD4(1) inhibitors using protein-ligand docking and structure-guided design.

    Science.gov (United States)

    Duffy, Bryan C; Liu, Shuang; Martin, Gregory S; Wang, Ruifang; Hsia, Ming Min; Zhao, He; Guo, Cheng; Ellis, Michael; Quinn, John F; Kharenko, Olesya A; Norek, Karen; Gesner, Emily M; Young, Peter R; McLure, Kevin G; Wagner, Gregory S; Lakshminarasimhan, Damodharan; White, Andre; Suto, Robert K; Hansen, Henrik C; Kitchen, Douglas B

    2015-07-15

    Bromodomains are key transcriptional regulators that are thought to be druggable epigenetic targets for cancer, inflammation, diabetes and cardiovascular therapeutics. Of particular importance is the first of two bromodomains in bromodomain containing 4 protein (BRD4(1)). Protein-ligand docking in BRD4(1) was used to purchase a small, focused screening set of compounds possessing a large variety of core structures. Within this set, a small number of weak hits each contained a dihydroquinoxalinone ring system. We purchased other analogs with this ring system and further validated the new hit series and obtained improvement in binding inhibition. Limited exploration by new analog synthesis showed that the binding inhibition in a FRET assay could be improved to the low μM level making this new core a potential hit-to-lead series. Additionally, the predicted geometries of the initial hit and an improved analog were confirmed by X-ray co-crystallography with BRD4(1). Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Diverse modes of binding in structures of Leishmania majorN-myristoyltransferase with selective inhibitors

    Directory of Open Access Journals (Sweden)

    James A. Brannigan

    2014-07-01

    Full Text Available The leishmaniases are a spectrum of global diseases of poverty associated with immune dysfunction and are the cause of high morbidity. Despite the long history of these diseases, no effective vaccine is available and the currently used drugs are variously compromised by moderate efficacy, complex side effects and the emergence of resistance. It is therefore widely accepted that new therapies are needed. N-Myristoyltransferase (NMT has been validated pre-clinically as a target for the treatment of fungal and parasitic infections. In a previously reported high-throughput screening program, a number of hit compounds with activity against NMT from Leishmania donovani have been identified. Here, high-resolution crystal structures of representative compounds from four hit series in ternary complexes with myristoyl-CoA and NMT from the closely related L. major are reported. The structures reveal that the inhibitors associate with the peptide-binding groove at a site adjacent to the bound myristoyl-CoA and the catalytic α-carboxylate of Leu421. Each inhibitor makes extensive apolar contacts as well as a small number of polar contacts with the protein. Remarkably, the compounds exploit different features of the peptide-binding groove and collectively occupy a substantial volume of this pocket, suggesting that there is potential for the design of chimaeric inhibitors with significantly enhanced binding. Despite the high conservation of the active sites of the parasite and human NMTs, the inhibitors act selectively over the host enzyme. The role of conformational flexibility in the side chain of Tyr217 in conferring selectivity is discussed.

  5. Synthesis and bioevaluation of new tacrine-cinnamic acid hybrids as cholinesterase inhibitors against Alzheimer's disease.

    Science.gov (United States)

    Chen, Yao; Zhu, Jie; Mo, Jun; Yang, Hongyu; Jiang, Xueyang; Lin, Hongzhi; Gu, Kai; Pei, Yuqiong; Wu, Liang; Tan, Renxiang; Hou, Jing; Chen, Jingyi; Lv, Yang; Bian, Yaoyao; Sun, Haopeng

    2018-12-01

    Small molecule cholinesterases inhibitor (ChEI) provides an effective therapeutic strategy to treat Alzheimer's disease (AD). Currently, the discovery of new ChEI with multi-target effect is still of great importance. Herein, we report the synthesis, structure-activity relationship study and biological evaluation of a series of tacrine-cinnamic acid hybrids as new ChEIs. All target compounds are evaluated for their in vitro cholinesterase inhibitory activities. The representatives which show potent activity on cholinesterase, are evaluated for the amyloid β-protein self-aggregation inhibition and in vivo assays. The optimal compound 19, 27, and 30 (human AChE IC 50  = 10.2 ± 1.2, 16.5 ± 1.7, and 15.3 ± 1.8 nM, respectively) show good performance in ameliorating the scopolamine-induced cognition impairment and preliminary safety in hepatotoxicity evaluation. These compounds deserve further evaluation for the development of new therapeutic agents against AD.

  6. A high throughput screening assay for identifying glycation inhibitors on MALDI-TOF target.

    Science.gov (United States)

    Zhang, Qiuting; Tu, Zongcai; Wang, Hui; Fan, Liangliang; Huang, Xiaoqin; Xiao, Hui

    2015-03-01

    The Maillard reaction plays an important role in the food industry, however, the deleterious effects generated by the advanced glycation end-products (AGEs) have been well recognized. Many efforts have been made to seek new AGE inhibitors, in particular those natural ones without adverse effect. We have developed a rapid, mass spectrometry based, on-plate screening assay for novel AGE inhibitors. The glycation reaction, inhibition feedback as well as the subsequent MALDI mass spectrometric analysis occurred on one single MALDI plate. At 1:10 M ratio of peptide to sugar, as little as 4h incubation time allowed the screening test to be ready for analysis. DSP, inhibition and IC50 were calculated to evaluate selected inhibitors and resulting inhibition efficiencies were consistent with available references. We demonstrated that this method provide a potential high throughput screening assay to analyze and identify the anti-glycation agents. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. SAR and characterization of non-substrate isoindoline urea inhibitors of nicotinamide phosphoribosyltransferase (NAMPT)

    Energy Technology Data Exchange (ETDEWEB)

    Curtin, Michael L.; Heyman, H. Robin; Clark, Richard F.; Sorensen, Bryan K.; Doherty, George A.; Hansen, T. Matthew; Frey, Robin R.; Sarris, Kathy A.; Aguirre, Ana L.; Shrestha, Anurupa; Tu, Noah; Woller, Kevin; Pliushchev, Marina A.; Sweis, Ramzi F.; Cheng, Min; Wilsbacher, Julie L.; Kovar, Peter J.; Guo, Jun; Cheng, Dong; Longenecker, Kenton L.; Raich, Diana; Korepanova, Alla V.; Soni, Nirupama B.; Algire, Mikkel A.; Richardson, Paul L.; Marin, Violeta L.; Badagnani, Ilaria; Vasudevan, Anil; Buchanan, F.Greg; Maag, David; Chiang, Gary G.; Tse, Chris; Michaelides, Michael R. (AbbVie)

    2017-08-01

    Herein we disclose SAR studies that led to a series of isoindoline ureas which we recently reported were first-in-class, non-substrate nicotinamide phosphoribosyltransferase (NAMPT) inhibitors. Modification of the isoindoline and/or the terminal functionality of screening hit 5 provided inhibitors such as 52 and 58 with nanomolar antiproliferative activity and preclinical pharmacokinetics properties which enabled potent antitumor activity when dosed orally in mouse xenograft models. X-ray crystal structures of two inhibitors bound in the NAMPT active-site are discussed.

  8. Tyrosine kinase receptor inhibitor-targeted combined chemotherapy for metastatic bladder cancer

    Directory of Open Access Journals (Sweden)

    Chia-Lun Wu

    2012-04-01

    increased subG1 in cell cycle was seen in the epirubicin and sunitinib combination treatment group. The activation of apoptosis pathway was confirmed by increased cleaved caspase-3 and cleaved PARP in MBT-2 cells. In tail vein tumor inoculation C3H mice model, epirubicin alone and sunitinib combination therapy decreased tumor growth in lungs with marginal effect. Sunitinib and epirubicin combination had shown a synergistic cytotoxic effect and inhibited cell migration ability in MBT-2 cells. The combination can induce cell cycle arrest at G2/M phase and increase subG1 cells. Metastatic animal study also showed that sunitinib combined with epirubicin has a marginal effect on inhibition of tumor growth of lungs. The tyrosine kinase receptor inhibitor-targeted combined chemotherapy regimen may provide as a new treatment modality for advanced bladder cancer in the future.

  9. Molecular Design, Synthesis and Trypanocidal Activity of Dipeptidyl Nitriles as Cruzain Inhibitors

    Science.gov (United States)

    Avelar, Leandro A. A.; Camilo, Cristian D.; de Albuquerque, Sérgio; Fernandes, William B.; Gonçalez, Cristiana; Kenny, Peter W.; Leitão, Andrei; McKerrow, James H.; Montanari, Carlos A.; Orozco, Erika V. Meñaca; Ribeiro, Jean F. R.; Rocha, Josmar R.; Rosini, Fabiana; Saidel, Marta E.

    2015-01-01

    A series of compounds based on the dipeptidyl nitrile scaffold were synthesized and assayed for their inhibitory activity against the T. cruzi cysteine protease cruzain. Structure activity relationships (SARs) were established using three, eleven and twelve variations respectively at the P1, P2 and P3 positions. A K i value of 16 nM was observed for the most potent of these inhibitors which reflects a degree of non-additivity in the SAR. An X-ray crystal structure was determined for the ligand-protein complex for the structural prototype for the series. Twenty three inhibitors were also evaluated for their anti-trypanosomal effects and an EC50 value of 28 μM was observed for the most potent of these. Although there remains scope for further optimization, the knowledge gained from this study is also transferable to the design of cruzain inhibitors based on warheads other than nitrile as well as alternative scaffolds. PMID:26173110

  10. Discovery of novel high potent and cellular active ADC type PTP1B inhibitors with selectivity over TC-PTP via modification interacting with C site.

    Science.gov (United States)

    Du, Yongli; Zhang, Yanhui; Ling, Hao; Li, Qunyi; Shen, Jingkang

    2018-01-20

    PTP1B serving as a key negative regulator of insulin signaling is a novel target for type 2 diabetes and obesity. Modification at ring B of N-{4-[(3-Phenyl-ureido)-methyl]-phenyl}-methane-sulfonamide template to interact with residues Arg47 and Lys41 in the C site of PTP1B by molecular docking aided design resulted in the discovery of a series of novel high potent and selective inhibitors of PTP1B. The structure activity relationship interacting with the C site of PTP1B was well illustrated. Compounds 8 and 18 were shown to be the high potent and most promising PTP1B inhibitors with cellular activity and great selectivity over the highly homologous TCPTP and other PTPs. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. Discovery and Characterization of Non-ATP Site Inhibitors of the Mitogen Activated Protein (MAP) Kinases

    Energy Technology Data Exchange (ETDEWEB)

    Comess, Kenneth M.; Sun, Chaohong; Abad-Zapatero, Cele; Goedken, Eric R.; Gum, Rebecca J.; Borhani, David W.; Argiriadi, Maria; Groebe, Duncan R.; Jia, Yong; Clampit, Jill E.; Haasch, Deanna L.; Smith, Harriet T.; Wang, Sanyi; Song, Danying; Coen, Michael L.; Cloutier, Timothy E.; Tang, Hua; Cheng, Xueheng; Quinn, Christopher; Liu, Bo; Xin, Zhili; Liu, Gang; Fry, Elizabeth H.; Stoll, Vincent; Ng, Teresa I.; Banach, David; Marcotte, Doug; Burns, David J.; Calderwood, David J.; Hajduk, Philip J. (Abbott)

    2012-03-02

    Inhibition of protein kinases has validated therapeutic utility for cancer, with at least seven kinase inhibitor drugs on the market. Protein kinase inhibition also has significant potential for a variety of other diseases, including diabetes, pain, cognition, and chronic inflammatory and immunologic diseases. However, as the vast majority of current approaches to kinase inhibition target the highly conserved ATP-binding site, the use of kinase inhibitors in treating nononcology diseases may require great selectivity for the target kinase. As protein kinases are signal transducers that are involved in binding to a variety of other proteins, targeting alternative, less conserved sites on the protein may provide an avenue for greater selectivity. Here we report an affinity-based, high-throughput screening technique that allows nonbiased interrogation of small molecule libraries for binding to all exposed sites on a protein surface. This approach was used to screen both the c-Jun N-terminal protein kinase Jnk-1 (involved in insulin signaling) and p38{alpha} (involved in the formation of TNF{alpha} and other cytokines). In addition to canonical ATP-site ligands, compounds were identified that bind to novel allosteric sites. The nature, biological relevance, and mode of binding of these ligands were extensively characterized using two-dimensional {sup 1}H/{sup 13}C NMR spectroscopy, protein X-ray crystallography, surface plasmon resonance, and direct enzymatic activity and activation cascade assays. Jnk-1 and p38{alpha} both belong to the MAP kinase family, and the allosteric ligands for both targets bind similarly on a ledge of the protein surface exposed by the MAP insertion present in the CMGC family of protein kinases and distant from the active site. Medicinal chemistry studies resulted in an improved Jnk-1 ligand able to increase adiponectin secretion in human adipocytes and increase insulin-induced protein kinase PKB phosphorylation in human hepatocytes, in

  12. HIV-1 gp41 Fusion Intermediate: A Target for HIV Therapeutics

    Directory of Open Access Journals (Sweden)

    Chungen Pan

    2010-02-01

    Full Text Available Human immunodeficiency virus (HIV-1 infection is initiated by the binding of gp120 envelope glyco-protein to its cell receptor (CD4 and a coreceptor (CXCR4 or CCR5, followed by a series of conformational changes in the gp41 transmembrane subunit. These changes include insertion of fusion peptide into the target cell membrane and association of C-heptad repeat (CHR peptide with the N-heptad repeat (NHR trimer, a pre-hairpin fusion intermediate. A stable six-helix bundle core is then formed, bringing the viral envelope and target cell membrane into close proximity for fusion. Peptides derived from the CHR region, such as T20 and C34, inhibit HIV-1 fusion by interacting with the gp41 fusion intermediate. A number of anti-HIV-1 peptides and small molecule compounds targeting the gp41 NHR-trimer have been identified. By combining HIV fusion/entry inhibitors targeting different sites in the gp41 fusion intermediate, a potent synergistic effect takes place, resulting in a potential new therapeutic strategy for the HIV infection/AIDS. Here, we present an overview of the current development of anti-HIV drugs, particularly those targeting the gp41 fusion intermediate.

  13. Inhibitors of steroidal cytochrome p450 enzymes as targets for drug development.

    Science.gov (United States)

    Baston, Eckhard; Leroux, Frédéric R

    2007-01-01

    Cytochrome P450's are enzymes which catalyze a large number of biological reactions, for example hydroxylation, N-, O-, S- dealkylation, epoxidation or desamination. Their substrates include fatty acids, steroids or prostaglandins. In addition, a high number of various xenobiotics are metabolized by these enzymes. The enzyme 17alpha-hydroxylase-C17,20-lyase (P450(17), CYP 17, androgen synthase), a cytochrome P450 monooxygenase, is the key enzyme for androgen biosynthesis. It catalyzes the last step of the androgen biosynthesis in the testes and adrenal glands and produces androstenedione and dehydroepiandrosterone from progesterone and pregnenolone. The microsomal enzyme aromatase (CYP19) transforms these androgens to estrone and estradiol. Estrogens stimulate tumor growth in hormone dependent breast cancer. In addition, about 80 percent of prostate cancers are androgen dependent. Selective inhibitors of these enzymes are thus important alternatives to treatment options like antiandrogens or antiestrogens. The present article deals with recent patents (focus on publications from 2000 - 2006) concerning P450 inhibitor design where steroidal substrates are involved. In this context a special focus is provided for CYP17 and CYP19. Mechanisms of action will also be discussed. Inhibitors of CYP11B2 (aldosterone synthase) will also be dealt with.

  14. IspE inhibitors identified by a combination of in silico and in vitro high-throughput screening.

    Directory of Open Access Journals (Sweden)

    Naomi Tidten-Luksch

    Full Text Available CDP-ME kinase (IspE contributes to the non-mevalonate or deoxy-xylulose phosphate (DOXP pathway for isoprenoid precursor biosynthesis found in many species of bacteria and apicomplexan parasites. IspE has been shown to be essential by genetic methods and since it is absent from humans it constitutes a promising target for antimicrobial drug development. Using in silico screening directed against the substrate binding site and in vitro high-throughput screening directed against both, the substrate and co-factor binding sites, non-substrate-like IspE inhibitors have been discovered and structure-activity relationships were derived. The best inhibitors in each series have high ligand efficiencies and favourable physico-chemical properties rendering them promising starting points for drug discovery. Putative binding modes of the ligands were suggested which are consistent with established structure-activity relationships. The applied screening methods were complementary in discovering hit compounds, and a comparison of both approaches highlights their strengths and weaknesses. It is noteworthy that compounds identified by virtual screening methods provided the controls for the biochemical screens.

  15. Vanadium Compounds as PTP Inhibitors

    Directory of Open Access Journals (Sweden)

    Elsa Irving

    2017-12-01

    Full Text Available Phosphotyrosine signaling is regulated by the opposing actions of protein tyrosine kinases (PTKs and protein tyrosine phosphatases (PTPs. Here we discuss the potential of vanadium derivatives as PTP enzyme inhibitors and metallotherapeutics. We describe how vanadate in the V oxidized state is thought to inhibit PTPs, thus acting as a pan-inhibitor of this enzyme superfamily. We discuss recent developments in the biological and biochemical actions of more complex vanadium derivatives, including decavanadate and in particular the growing number of oxidovanadium compounds with organic ligands. Pre-clinical studies involving these compounds are discussed in the anti-diabetic and anti-cancer contexts. Although in many cases PTP inhibition has been implicated, it is also clear that many such compounds have further biochemical effects in cells. There also remain concerns surrounding off-target toxicities and long-term use of vanadium compounds in vivo in humans, hindering their progress through clinical trials. Despite these current misgivings, interest in these chemicals continues and many believe they could still have therapeutic potential. If so, we argue that this field would benefit from greater focus on improving the delivery and tissue targeting of vanadium compounds in order to minimize off-target toxicities. This may then harness their full therapeutic potential.

  16. Structural Implications for Selective Targeting of PARPs.

    Science.gov (United States)

    Steffen, Jamin D; Brody, Jonathan R; Armen, Roger S; Pascal, John M

    2013-12-20

    Poly(ADP-ribose) polymerases (PARPs) are a family of enzymes that use NAD(+) as a substrate to synthesize polymers of ADP-ribose (PAR) as post-translational modifications of proteins. PARPs have important cellular roles that include preserving genomic integrity, telomere maintenance, transcriptional regulation, and cell fate determination. The diverse biological roles of PARPs have made them attractive therapeutic targets, which have fueled the pursuit of small molecule PARP inhibitors. The design of PARP inhibitors has matured over the past several years resulting in several lead candidates in clinical trials. PARP inhibitors are mainly used in clinical trials to treat cancer, particularly as sensitizing agents in combination with traditional chemotherapy to reduce side effects. An exciting aspect of PARP inhibitors is that they are also used to selectivity kill tumors with deficiencies in DNA repair proteins (e.g., BRCA1/2) through an approach termed "synthetic lethality." In the midst of the tremendous efforts that have brought PARP inhibitors to the forefront of modern chemotherapy, most clinically used PARP inhibitors bind to conserved regions that permits cross-selectivity with other PARPs containing homologous catalytic domains. Thus, the differences between therapeutic effects and adverse effects stemming from pan-PARP inhibition compared to selective inhibition are not well understood. In this review, we discuss current literature that has found ways to gain selectivity for one PARP over another. We furthermore provide insights into targeting other domains that make up PARPs, and how new classes of drugs that target these domains could provide a high degree of selectivity by affecting specific cellular functions. A clear understanding of the inhibition profiles of PARP inhibitors will not only enhance our understanding of the biology of individual PARPs, but may provide improved therapeutic options for patients.

  17. Acute toxicity of second generation HIV protease-inhibitors in combination with radiotherapy: a retrospective case series

    International Nuclear Information System (INIS)

    See, Alfred P; Zeng, Jing; Tran, Phuoc T; Lim, Michael

    2011-01-01

    There is little data on the safety of combining radiation therapy and human immunodeficiency virus (HIV) protease inhibitors to treat cancers in HIV-positive patients. We describe acute toxicities observed in a series of HIV-positive patients receiving modern radiation treatments, and compare patients receiving HIV protease inhibitors (PI) with patients not receiving HIV PIs. By reviewing the clinical records beginning January 1, 2009 from the radiation oncology department, we identified 29 HIV-positive patients who received radiation therapy to 34 body sites. Baseline information, treatment regimen, and toxicities were documented by review of medical records: patient age, histology and source of the primary tumor, HIV medication regimen, pre-radiation CD4 count, systemic chemotherapy, radiation therapy dose and fractionation, irradiated body region, toxicities, and duration of follow-up. Patients were grouped according to whether they received concurrent HIV PIs and compared using Pearson's chi-square test. At baseline, the patients in the two groups were similar with the exception of HIV medication regimens, CD4 count and presence of AIDS-defining malignancy. Patients taking concurrent PIs were more likely to be taking other HIV medications (p = 0.001) and have CD4 count >500 (p = 0.006). Patients taking PIs were borderline less likely to have an AIDS-defining malignancy (p = 0.06). After radiation treatment, 100 acute toxicities were observed and were equally common in both groups (64 [median 3 per patient, IQR 1-7] with PIs; 36 [median 3 per patient, IQR 2-3] without PIs). The observed toxicities were also equally severe in the two groups (Grades I, II, III respectively: 30, 30, 4 with PIs; 23, 13, 0 without PIs: p = 0.38). There were two cases that were stopped early, one in each group; these were not attributable to toxicity. In this study of recent radiotherapy in HIV-positive patients taking second generation PIs, no difference in toxicities was

  18. Applying ligands profiling using multiple extended electron distribution based field templates and feature trees similarity searching in the discovery of new generation of urea-based antineoplastic kinase inhibitors.

    Directory of Open Access Journals (Sweden)

    Eman M Dokla

    Full Text Available This study provides a comprehensive computational procedure for the discovery of novel urea-based antineoplastic kinase inhibitors while focusing on diversification of both chemotype and selectivity pattern. It presents a systematic structural analysis of the different binding motifs of urea-based kinase inhibitors and the corresponding configurations of the kinase enzymes. The computational model depends on simultaneous application of two protocols. The first protocol applies multiple consecutive validated virtual screening filters including SMARTS, support vector-machine model (ROC = 0.98, Bayesian model (ROC = 0.86 and structure-based pharmacophore filters based on urea-based kinase inhibitors complexes retrieved from literature. This is followed by hits profiling against different extended electron distribution (XED based field templates representing different kinase targets. The second protocol enables cancericidal activity verification by using the algorithm of feature trees (Ftrees similarity searching against NCI database. Being a proof-of-concept study, this combined procedure was experimentally validated by its utilization in developing a novel series of urea-based derivatives of strong anticancer activity. This new series is based on 3-benzylbenzo[d]thiazol-2(3H-one scaffold which has interesting chemical feasibility and wide diversification capability. Antineoplastic activity of this series was assayed in vitro against NCI 60 tumor-cell lines showing very strong inhibition of GI(50 as low as 0.9 uM. Additionally, its mechanism was unleashed using KINEX™ protein kinase microarray-based small molecule inhibitor profiling platform and cell cycle analysis showing a peculiar selectivity pattern against Zap70, c-src, Mink1, csk and MeKK2 kinases. Interestingly, it showed activity on syk kinase confirming the recent studies finding of the high activity of diphenyl urea containing compounds against this kinase. Allover, the new series

  19. A Sensitive in Vitro High-Throughput Screen To Identify Pan-filoviral Replication Inhibitors Targeting the VP35–NP Interface

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Gai; Nash, Peter J.; Johnson, Britney; Pietzsch, Colette; Ilagan, Ma. Xenia G.; Bukreyev, Alexander; Basler, Christopher F.; Bowlin, Terry L.; Moir, Donald T.; Leung, Daisy W.; Amarasinghe, Gaya K. (WU-MED); (GSU); (Texas-MED); (Microbiotix)

    2017-01-24

    The 2014 Ebola outbreak in West Africa, the largest outbreak on record, highlighted the need for novel approaches to therapeutics targeting Ebola virus (EBOV). Within the EBOV replication complex, the interaction between polymerase cofactor, viral protein 35 (VP35), and nucleoprotein (NP) is critical for viral RNA synthesis. We recently identified a peptide at the N-terminus of VP35 (termed NPBP) that is sufficient for interaction with NP and suppresses EBOV replication, suggesting that the NPBP binding pocket can serve as a potential drug target. Here we describe the development and validation of a sensitive high-throughput screen (HTS) using a fluorescence polarization assay. Initial hits from this HTS include the FDA-approved compound tolcapone, whose potency against EBOV infection was validated in a nonfluorescent secondary assay. High conservation of the NP–VP35 interface among filoviruses suggests that this assay has the capacity to identify pan-filoviral inhibitors for development as antivirals.

  20. Targeting colorectal cancer cells by a novel sphingosine kinase 1 inhibitor PF-543

    International Nuclear Information System (INIS)

    Ju, TongFa; Gao, DaQuan; Fang, Zheng-yu

    2016-01-01

    In this study, we showed that PF-543, a novel sphingosine kinase 1 (SphK1) inhibitor, exerted potent anti-proliferative and cytotoxic effects against a panel of established (HCT-116, HT-29 and DLD-1) and primary human colorectal cancer (CRC) cells. Its sensitivity was negatively associated with SphK1 expression level in the CRC cells. Surprisingly, PF-543 mainly induced programmed necrosis, but not apoptosis, in the CRC cells. CRC cell necrotic death was detected by lactate dehydrogenase (LDH) release, mitochondrial membrane potential (MMP) collapse and mitochondrial P53-cyclophilin-D (Cyp-D) complexation. Correspondingly, the necrosis inhibitor necrostatin-1 largely attenuated PF-543-induced cytotoxicity against CRC cells. Meanwhile, the Cyp-D inhibitors (sanglifehrin A and cyclosporin A), or shRNA-mediated knockdown of Cyp-D, remarkably alleviated PF-543-induced CRC cell necrotic death. Reversely, over-expression of wild-type Cyp-D in HCT-116 cells significantly increased PF-543's sensitivity. In vivo, PF-543 intravenous injection significantly suppressed HCT-116 xenograft growth in severe combined immunodeficient (SCID) mice, whiling remarkably improving the mice survival. The in vivo activity by PF-543 was largely attenuated when combined with the Cyp-D inhibitor cyclosporin A. Collectively, our results demonstrate that PF-543 exerts potent anti-CRC activity in vitro and in vivo. Mitochondrial programmed necrosis pathway is likely the key mechanism responsible for PF-543's actions in CRC cells. - Highlights: • PF-543 is anti-proliferative and cytotoxic to established and primary CRC cells. • PF-543 induces programmed necrosis, but not apoptosis, in CRC cells. • Modulation of mitochondrial protein cyclophilin-D alters PF-543's sensitivity. • PF-543 inhibits HCT-116 xenograft growth in SCID mice, improving mice survival. • Co-administration of cyclophilin-D inhibitor CsA inhibits PF-543's activity in vivo.

  1. Targeting colorectal cancer cells by a novel sphingosine kinase 1 inhibitor PF-543

    Energy Technology Data Exchange (ETDEWEB)

    Ju, TongFa [Department of Anal-colorectal Surgery, HangZhou First People' s Hospital, HangZhou (China); Gao, DaQuan [Hematological Department, HangZhou First People' s Hospital, HangZhou (China); Fang, Zheng-yu, E-mail: fangzhengyu158@sina.com [Department of Anal-colorectal Surgery, The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou (China)

    2016-02-12

    In this study, we showed that PF-543, a novel sphingosine kinase 1 (SphK1) inhibitor, exerted potent anti-proliferative and cytotoxic effects against a panel of established (HCT-116, HT-29 and DLD-1) and primary human colorectal cancer (CRC) cells. Its sensitivity was negatively associated with SphK1 expression level in the CRC cells. Surprisingly, PF-543 mainly induced programmed necrosis, but not apoptosis, in the CRC cells. CRC cell necrotic death was detected by lactate dehydrogenase (LDH) release, mitochondrial membrane potential (MMP) collapse and mitochondrial P53-cyclophilin-D (Cyp-D) complexation. Correspondingly, the necrosis inhibitor necrostatin-1 largely attenuated PF-543-induced cytotoxicity against CRC cells. Meanwhile, the Cyp-D inhibitors (sanglifehrin A and cyclosporin A), or shRNA-mediated knockdown of Cyp-D, remarkably alleviated PF-543-induced CRC cell necrotic death. Reversely, over-expression of wild-type Cyp-D in HCT-116 cells significantly increased PF-543's sensitivity. In vivo, PF-543 intravenous injection significantly suppressed HCT-116 xenograft growth in severe combined immunodeficient (SCID) mice, whiling remarkably improving the mice survival. The in vivo activity by PF-543 was largely attenuated when combined with the Cyp-D inhibitor cyclosporin A. Collectively, our results demonstrate that PF-543 exerts potent anti-CRC activity in vitro and in vivo. Mitochondrial programmed necrosis pathway is likely the key mechanism responsible for PF-543's actions in CRC cells. - Highlights: • PF-543 is anti-proliferative and cytotoxic to established and primary CRC cells. • PF-543 induces programmed necrosis, but not apoptosis, in CRC cells. • Modulation of mitochondrial protein cyclophilin-D alters PF-543's sensitivity. • PF-543 inhibits HCT-116 xenograft growth in SCID mice, improving mice survival. • Co-administration of cyclophilin-D inhibitor CsA inhibits PF-543's activity in vivo.

  2. Design and synthesis of imidazopyridine analogues as inhibitors of phosphoinositide 3-kinase signaling and angiogenesis.

    Science.gov (United States)

    Kim, Okseon; Jeong, Yujeong; Lee, Hyunseung; Hong, Sun-Sun; Hong, Sungwoo

    2011-04-14

    Phosphatidylinositol 3-kinase α (PI3Kα) is an important regulator of intracellular signaling pathways, controlling remarkably diverse arrays of physiological processes. Because the PI3K pathway is frequently up-regulated in human cancers, the inhibition of PI3Kα can be a promising approach to cancer therapy. In this study, we have designed and synthesized a new series of imidazo[1,2-a]pyridine derivatives as PI3Kα inhibitors through the fragment-growing strategy. By varying groups at the 3- and 6-positions of imidazo[1,2-a]pyridines, we studied the structure-activity relationships (SAR) profiles and identified a series of potent PI3Kα inhibitors. Representative derivatives showed good activity in cellular proliferation and apoptosis assays. Moreover, these inhibitors exhibited noteworthy antiangiogenic activity.

  3. Studies of axon-glial cell interactions and periaxonal K+ homeostasis--II. The effect of axonal stimulation, cholinergic agents and transport inhibitors on the resistance in series with the axon membrane.

    Science.gov (United States)

    Hassan, S; Lieberman, E M

    1988-06-01

    The small electrical resistance in series with the axon membrane is generally modeled as the intercellular pathway for current flow through the periaxonal glial (Schwann cell) sheath. The series resistance of the medial giant axon of the crayfish, Procambarus clarkii, was found to vary with conditions known to affect the electrical properties of the periaxonal glia. Series resistance was estimated from computer analysed voltage waveforms generated by axial wire-constant current and space clamp techniques. The average series resistance for all axons was 6.2 +/- 0.5 omega cm2 (n = 128). Values ranged between 1 and 30 omega cm2. The series resistance of axons with low resting membrane resistance (less than 1500 omega cm2) increased an average of 30% when stimulated for 45 s to 7 min (50 Hz) whereas the series resistance of high membrane resistance (greater than 1500 omega cm2) axons decreased an average of 10%. Carbachol (10(-7) M) caused the series resistance of low membrane resistance axons to decrease during stimulation but had no effect on high membrane resistance axons. d-Tubocurare (10(-8) M) caused the series resistance of high membrane resistance axons to increase during stimulation but had no effect on low membrane resistance axons. Bumetanide, a Na-K-Cl cotransport inhibitor and low [K+]o, prevented the stimulation-induced increase in series resistance of low membrane resistance axons but had no effect on the high membrane resistance axons. The results suggest that the series resistance of axons varies in response to the activity of the glial K+ uptake mechanisms stimulated by the appearance of K+ in the periaxonal space during action potential generation.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. FDA-approved small-molecule kinase inhibitors

    DEFF Research Database (Denmark)

    Wu, Peng; Nielsen, Thomas E.; Clausen, Mads Hartvig

    2015-01-01

    Kinases have emerged as one of the most intensivelypursued targets in current pharmacological research,especially for cancer, due to their critical roles in cellularsignaling. To date, the US FDA has approved 28 smallmoleculekinase inhibitors, half of which were approvedin the past 3 years. While...

  5. First report on the structural exploration and prediction of new BPTES analogs as glutaminase inhibitors

    Science.gov (United States)

    Amin, Sk. Abdul; Adhikari, Nilanjan; Gayen, Shovanlal; Jha, Tarun

    2017-09-01

    Glutaminase is one of the important key enzymes regulating cellular metabolism, growth, and proliferation in cancer. Therefore, it is being explored as a crucial target regarding anticancer drug design and development. However, none of the potent and selective glutaminase inhibitors is available in the market though two prototype glutaminase inhibitors are reported namely DON as well as BPTES. Due to severe toxicity in clinical trials, the use of DON is restricted. However, BPTES is an allosteric glutaminase inhibitor with less toxic profile and, therefore, lead optimization of BPTES may be a good option to develop newer drug candidates. In this study, a multi-QSAR modeling is carried out on a series of BPTES analogs. A significant connection between different descriptors and the glutaminase inhibitory activities is noticed by employing multiple linear regression, artificial neural network and support vector machine techniques. The classification-based QSAR such as linear discriminant analysis and Bayesian classification modeling are also performed to search important molecular fingerprints or substructures that may help in classifying the probability of finding 'active' and 'inactive' BPTES analogs. Moreover, HQSAR and Topomer CoMFA analyses are also performed. In addition, the SAR observations are interpreted with all these validated computational models along with the structure-based contours. Finally, new twenty two compounds are designed and predicted for their probable glutaminase inhibitory activity.

  6. Histone deacetylase inhibitors (HDACIs): multitargeted anticancer agents.

    Science.gov (United States)

    Ververis, Katherine; Hiong, Alison; Karagiannis, Tom C; Licciardi, Paul V

    2013-01-01

    Histone deacetylase (HDAC) inhibitors are an emerging class of therapeutics with potential as anticancer drugs. The rationale for developing HDAC inhibitors (and other chromatin-modifying agents) as anticancer therapies arose from the understanding that in addition to genetic mutations, epigenetic changes such as dysregulation of HDAC enzymes can alter phenotype and gene expression, disturb homeostasis, and contribute to neoplastic growth. The family of HDAC inhibitors is large and diverse. It includes a range of naturally occurring and synthetic compounds that differ in terms of structure, function, and specificity. HDAC inhibitors have multiple cell type-specific effects in vitro and in vivo, such as growth arrest, cell differentiation, and apoptosis in malignant cells. HDAC inhibitors have the potential to be used as monotherapies or in combination with other anticancer therapies. Currently, there are two HDAC inhibitors that have received approval from the US FDA for the treatment of cutaneous T-cell lymphoma: vorinostat (suberoylanilide hydroxamic acid, Zolinza) and depsipeptide (romidepsin, Istodax). More recently, depsipeptide has also gained FDA approval for the treatment of peripheral T-cell lymphoma. Many more clinical trials assessing the effects of various HDAC inhibitors on hematological and solid malignancies are currently being conducted. Despite the proven anticancer effects of particular HDAC inhibitors against certain cancers, many aspects of HDAC enzymes and HDAC inhibitors are still not fully understood. Increasing our understanding of the effects of HDAC inhibitors, their targets and mechanisms of action will be critical for the advancement of these drugs, especially to facilitate the rational design of HDAC inhibitors that are effective as antineoplastic agents. This review will discuss the use of HDAC inhibitors as multitargeted therapies for malignancy. Further, we outline the pharmacology and mechanisms of action of HDAC inhibitors while

  7. Novel Therapeutic Targets for Phosphodiesterase 5 Inhibitors: current state-of-the-art on systemic arterial hypertension and atherosclerosis.

    Science.gov (United States)

    Vasquez, Elisardo C; Gava, Agata L; Graceli, Jones B; Balarini, Camille M; Campagnaro, Bianca P; Pereira, Thiago Melo C; Meyrelles, Silvana S

    2016-01-01

    The usefulness of selective inhibitors of phosphodiesterase 5 (PDE5) is well known, first for the treatment of male erectile dysfunction and more recently for pulmonary hypertension. The discovery that PDE5 is present in the systemic artery endothelium and smooth muscle cells led investigators to test the extra sexual effects of sildenafil, the first and most investigated PDE5 inhibitor, in diseases affecting the systemic arteries. Cumulative data from experimental and clinical studies have revealed beneficial effects of sildenafil on systemic arterial hypertension and its target organs, such as the heart, kidneys and vasculature. An important effect of sildenafil is reduction of hypertension and improvement of endothelial function in experimental models of hypertension and hypertensive subjects. Interestingly, in angiotensin-dependent hypertension, its beneficial effects on endothelial and kidney dysfunctions seem to at least in part be caused by its ability to decrease the levels of angiotensin II and increase angiotensin 1-7, in addition to improving nitric oxide bioavailability and diminishing reactive oxygen species. Another remarkable finding on the effects of sildenafil comes from studies in apolipoprotein E knockout mice, a model of atherosclerosis that closely resembles human atherosclerotic disease. In this review, we focus on the promising beneficial effects of sildenafil for treating systemic high blood pressure, especially resistant hypertension, and the endothelial dysfunction that is present in hypertension and atherosclerosis.

  8. Designing inhibitors of cytochrome c/cardiolipin peroxidase complexes: mitochondria-targeted imidazole-substituted fatty acids.

    Science.gov (United States)

    Jiang, Jianfei; Bakan, Ahmet; Kapralov, Alexandr A; Silva, K Ishara; Huang, Zhentai; Amoscato, Andrew A; Peterson, James; Garapati, Venkata Krishna; Saxena, Sunil; Bayir, Hülya; Atkinson, Jeffrey; Bahar, Ivet; Kagan, Valerian E

    2014-06-01

    Mitochondria have emerged as the major regulatory platform responsible for the coordination of numerous metabolic reactions as well as cell death processes, whereby the execution of intrinsic apoptosis includes the production of reactive oxygen species fueling oxidation of cardiolipin (CL) catalyzed by cytochrome (Cyt) c. As this oxidation occurs within the peroxidase complex of Cyt c with CL, the latter represents a promising target for the discovery and design of drugs with antiapoptotic mechanisms of action. In this work, we designed and synthesized a new group of mitochondria-targeted imidazole-substituted analogs of stearic acid TPP-n-ISAs with various positions of the attached imidazole group on the fatty acid (n = 6, 8, 10, 13, and 14). By using a combination of absorption spectroscopy and EPR protocols (continuous wave electron paramagnetic resonance and electron spin echo envelope modulation) we demonstrated that TPP-n-ISAs indeed were able to potently suppress CL-induced structural rearrangements in Cyt c, paving the way to its peroxidase competence. TPP-n-ISA analogs preserved the low-spin hexa-coordinated heme-iron state in Cyt c/CL complexes whereby TPP-6-ISA displayed a significantly more effective preservation pattern than TPP-14-ISA. Elucidation of these intermolecular stabilization mechanisms of Cyt c identified TPP-6-ISA as an effective inhibitor of the peroxidase function of Cyt c/CL complexes with a significant antiapoptotic potential realized in mouse embryonic cells exposed to ionizing irradiation. These experimental findings were detailed and supported by all-atom molecular dynamics simulations. Based on the experimental data and computation predictions, we identified TPP-6-ISA as a candidate drug with optimized antiapoptotic potency. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Synthesis and in vitro Evaluation of 2-heteroarylidene-1-tetralone Derivatives as Monoamine Oxidase Inhibitors.

    Science.gov (United States)

    Amakali, Klaudia T; Legoabe, Lesetja J; Petzer, Anél; Petzer, Jacobus P

    2018-05-14

    The present study investigates the human monoamine oxidase (MAO) inhibition properties of a series of twelve 2-heteroarylidene-1-tetralone derivatives. Also included are related cyclohexylmethylidene, cyclopentylmethylidene and benzylidene substituted 1-tetralones. These compounds are related to the 2-benzylidene-1-indanone class of compounds which has previously been shown to inhibit the MAOs, with specificity for the MAO-B isoform. The target compounds were synthesised by the Claisen-Schmidt condensation between 7-methoxy-1-tetralone or 1-tetralone, and various aldehydes, under acid (hydrochloric acid) or base (potassium hydroxide) catalysis. The results of the MAO inhibition studies showed that the 2-heteroarylidene-1-tetralone and related derivatives are in most instances more selective inhibitors of the MAO-B isoform compared to MAO-A. (2E)-2-Benzylidene-7-methoxy-3,4-dihydronaphthalen-1(2 H)-one (IC 50 =0.707 μM) was found to be the most potent MAO-B inhibitor, while the most potent MAO-A inhibitor was (2E)-2-[(2-chloropyridin-3-yl)methylidene]-7-methoxy-3,4-dihydronaphthalen-1(2 H)-one (IC 50 =1.37 μM). The effect of the heteroaromatic substituent on MAO-B inhibition activity, in decreasing order was found to be: cyclohexyl, phenyl>thiophene>pyridine, furane, pyrrole, cyclopentyl. This study concludes that, although some 2-heteroarylidene-1-tetralone derivatives are good potency MAO inhibitors, in general their inhibition potencies, particularly for MAO-B, are lower than structurally related chalcones and 1-indanone derivatives that were previously studied. © Georg Thieme Verlag KG Stuttgart · New York.

  10. Recent advances in targeted drug therapy for hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    FAN Yongqiang

    2018-02-01

    Full Text Available More and more clinical trials have proved the efficacy of targeted drugs in the treatment of hepatocellular carcinoma (HCC. With the development of science and technology, more and more targeted drugs have appeared. In recent years, targeted drugs such as regorafenib and ramucirumab have shown great potential in related clinical trials. In addition, there are ongoing clinical trials for second-line candidate drugs, such as c-Met inhibitors tivantinib and cabozantinib and a VEGFR-2 inhibitor ramucirumab. This article summarizes the advances in targeted drug therapy for HCC and related trial data, which provides a reference for further clinical trials and treatment.

  11. Bacillus anthracis o-succinylbenzoyl-CoA synthetase: reaction kinetics and a novel inhibitor mimicking its reaction intermediate.

    Science.gov (United States)

    Tian, Yang; Suk, Dae-Hwan; Cai, Feng; Crich, David; Mesecar, Andrew D

    2008-11-25

    o-Succinylbenzoyl-CoA (OSB-CoA) synthetase (EC 6.2.1.26) catalyzes the ATP-dependent condensation of o-succinylbenzoate (OSB) and CoA to form OSB-CoA, the fourth step of the menaquinone biosynthetic pathway in Bacillus anthracis. Gene knockout studies have highlighted this enzyme as a potential target for the discovery of new antibiotics. Here we report the first studies on the kinetic mechanism of B. anthracis OSB-CoA synthetase, classifying it as an ordered bi uni uni bi ping-pong mechanism. Through a series of pre-steady-state and steady-state kinetic studies in conjunction with direct binding studies, it is demonstrated that CoA, the last substrate to bind, strongly activates the first half-reaction after the first round of turnover. The activation of the first half-reaction is most likely achieved by CoA stabilizing conformations of the enzyme in the "F" form, which slowly isomerize back to the E form. Thus, the kinetic mechanism of OSB-CoA synthetase may be more accurately described as an ordered bi uni uni bi iso ping-pong mechanism. The substrate specificity of OSB-CoA synthetase was probed using a series of OSB analogues with alterations in the carboxylate groups. OSB-CoA shows a strong preference for OSB over all of the analogues tested as none were active except 4-[2-(trifluoromethyl)phenyl]-4-oxobutyric acid which exhibited a 100-fold decrease in k(cat)/K(m). On the basis of an understanding of OSB-CoA synthetase's kinetic mechanism and substrate specificity, a reaction intermediate analogue of OSB-AMP, 5'-O-{N-[2-(trifluoromethyl)phenyl]-4-oxobutyl}adenosine sulfonamide (TFMP-butyl-AMS), was designed and synthesized. This inhibitor was found to be an uncompetitive inhibitor to CoA and a mixed-type inhibitor to ATP and OSB with low micromolar inhibition constants. Collectively, these results should serve as an important forerunner to more detailed and extensive inhibitor design studies aimed at developing lead compounds against the OSB-CoA synthetase

  12. JAK inhibitors for the treatment of myeloproliferative neoplasms and other disorders [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    William Vainchenker

    2018-01-01

    Full Text Available JAK inhibitors have been developed following the discovery of the JAK2V617F in 2005 as the driver mutation of the majority of non-BCR-ABL1 myeloproliferative neoplasms (MPNs. Subsequently, the search for JAK2 inhibitors continued with the discovery that the other driver mutations (CALR and MPL also exhibited persistent JAK2 activation. Several type I ATP-competitive JAK inhibitors with different specificities were assessed in clinical trials and exhibited minimal hematologic toxicity. Interestingly, these JAK inhibitors display potent anti-inflammatory activity. Thus, JAK inhibitors targeting preferentially JAK1 and JAK3 have been developed to treat inflammation, autoimmune diseases, and graft-versus-host disease. Ten years after the beginning of clinical trials, only two drugs have been approved by the US Food and Drug Administration: one JAK2/JAK1 inhibitor (ruxolitinib in intermediate-2 and high-risk myelofibrosis and hydroxyurea-resistant or -intolerant polycythemia vera and one JAK1/JAK3 inhibitor (tofacitinib in methotrexate-resistant rheumatoid arthritis. The non-approved compounds exhibited many off-target effects leading to neurological and gastrointestinal toxicities, as seen in clinical trials for MPNs. Ruxolitinib is a well-tolerated drug with mostly anti-inflammatory properties. Despite a weak effect on the cause of the disease itself in MPNs, it improves the clinical state of patients and increases survival in myelofibrosis. This limited effect is related to the fact that ruxolitinib, like the other type I JAK2 inhibitors, inhibits equally mutated and wild-type JAK2 (JAK2WT and also the JAK2 oncogenic activation. Thus, other approaches need to be developed and could be based on either (1 the development of new inhibitors specifically targeting JAK2V617F or (2 the combination of the actual JAK2 inhibitors with other therapies, in particular with molecules targeting pathways downstream of JAK2 activation or the stability of JAK2

  13. Discovery of a novel dual fungal CYP51/human 5-lipoxygenase inhibitor: implications for anti-fungal therapy.

    Directory of Open Access Journals (Sweden)

    Eric K Hoobler

    Full Text Available We report the discovery of a novel dual inhibitor targeting fungal sterol 14α-demethylase (CYP51 or Erg11 and human 5-lipoxygenase (5-LOX with improved potency against 5-LOX due to its reduction of the iron center by its phenylenediamine core. A series of potent 5-LOX inhibitors containing a phenylenediamine core, were synthesized that exhibit nanomolar potency and >30-fold selectivity against the LOX paralogs, platelet-type 12-human lipoxygenase, reticulocyte 15-human lipoxygenase type-1, and epithelial 15-human lipoxygenase type-2, and >100-fold selectivity against ovine cyclooxygenase-1 and human cyclooxygnease-2. The phenylenediamine core was then translated into the structure of ketoconazole, a highly effective anti-fungal medication for seborrheic dermatitis, to generate a novel compound, ketaminazole. Ketaminazole was found to be a potent dual inhibitor against human 5-LOX (IC50 = 700 nM and CYP51 (IC50 = 43 nM in vitro. It was tested in whole blood and found to down-regulate LTB4 synthesis, displaying 45% inhibition at 10 µM. In addition, ketaminazole selectively inhibited yeast CYP51 relative to human CYP51 by 17-fold, which is greater selectivity than that of ketoconazole and could confer a therapeutic advantage. This novel dual anti-fungal/anti-inflammatory inhibitor could potentially have therapeutic uses against fungal infections that have an anti-inflammatory component.

  14. Clinical trials for BET inhibitors run ahead of the science.

    Science.gov (United States)

    Andrieu, Guillaume; Belkina, Anna C; Denis, Gerald V

    2016-03-01

    Several cancer clinical trials for small molecule inhibitors of BET bromodomain proteins have been initiated. There is enthusiasm for the anti-proliferative effect of inhibiting BRD4, one of the targets of these inhibitors, which is thought to cooperate with MYC, a long-desired target for cancer therapeutics. However, no current inhibitor is selective for BRD4 among the three somatic BET proteins, which include BRD2 and BRD3; their respective functions are partially overlapping and none are functionally redundant with BRD4. Each BET protein controls distinct transcriptional pathways that are important for functions beyond cancer cell proliferation, including insulin production, cytokine gene transcription, T cell differentiation, adipogenesis and most seriously, active repression of dangerous latent viruses like HIV. BET inhibitors have been shown to reactivate HIV in human cells. Failure to appreciate that at concentrations used, no available BET inhibitor is member-selective, or to develop a sound biological basis to understand the diverse functions of BET proteins before undertaking for these clinical trials is reckless and likely to lead to adverse events. More mechanistic information from new basic science studies should enable proper focus on the most relevant cancers and define the expected side effect profiles. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. The Bruton Tyrosine Kinase (BTK) Inhibitor Acalabrutinib Demonstrates Potent On-Target Effects and Efficacy in Two Mouse Models of Chronic Lymphocytic Leukemia

    DEFF Research Database (Denmark)

    Herman, Sarah E M; Montraveta, Arnau; Niemann, Carsten U

    2017-01-01

    into the drinking water.Results: Utilizing biochemical assays, we demonstrate that acalabrutinib is a highly selective BTK inhibitor as compared with ibrutinib. In the human CLL NSG xenograft model, treatment with acalabrutinib demonstrated on-target effects, including decreased phosphorylation of PLCγ2, ERK......). In two complementary mouse models of CLL, acalabrutinib significantly reduced tumor burden and increased survival compared with vehicle treatment. Overall, acalabrutinib showed increased BTK selectivity compared with ibrutinib while demonstrating significant antitumor efficacy in vivo on par...... with ibrutinib. Clin Cancer Res; 23(11); 2831-41. ©2016 AACR....

  16. Synergistic Protective Effects of Mitochondrial Division Inhibitor 1 and Mitochondria-Targeted Small Peptide SS31 in Alzheimer's Disease.

    Science.gov (United States)

    Reddy, P Hemachandra; Manczak, Maria; Yin, XiangLing; Reddy, Arubala P

    2018-01-01

    The purpose of our study was to determine the synergistic protective effects of mitochondria-targeted antioxidant SS31 and mitochondria division inhibitor 1 (Mdivi1) in Alzheimer's disease (AD). Using biochemical methods, we assessed mitochondrial function by measuring the levels of hydrogen peroxide, lipid peroxidation, cytochrome c oxidase activity, mitochondrial ATP, and GTPase Drp1 enzymatic activity in mutant AβPP cells. Using biochemical methods, we also measured cell survival and apoptotic cell death. Amyloid-β (Aβ) levels were measured using sandwich ELISA, and using real-time quantitative RT-PCR, we assessed mtDNA (mtDNA) copy number in relation to nuclear DNA (nDNA) in all groups of cells. We found significantly reduced levels of Aβ40 and Aβ42 in mutant AβPP cells treated with SS31, Mdivi1, and SS31+Mdivi1, and the reduction of Aβ42 levels were much higher in SS31+Mdivi1 treated cells than individual treatments of SS31 and Mdivi1. The levels of mtDNA copy number and cell survival were significantly increased in SS31, Mdivi1, and SS31+Mdivi1 treated mutant AβPP cells; however, the increased levels of mtDNA copy number and cell survival were much higher in SS31+Mdivi1 treated cells than individual treatments of SS31 and Mdivi1. Mitochondrial dysfunction is significantly reduced in SS31, Mdivi1, and SS31+Mdivi1 treated mutant AβPP cells; however, the reduction is much higher in cells treated with both SS31+Mdvi1. Similarly, GTPase Drp1 activity is reduced in all treatments, but reduced much higher in SS31+Mdivi1 treated cells. These observations strongly suggest that combined treatment of SS31+Mdivi1 is effective than individual treatments of SS31 and Mdivi1. Therefore, we propose that combined treatment of SS31+Mdivi1 is a better therapeutic strategy for AD. Ours is the first study to investigate combined treatment of mitochondria-targeted antioxidant SS31 and mitochondrial division inhibitor 1 in AD neurons.

  17. Inhibitory Effects of Respiration Inhibitors on Aflatoxin Production

    Directory of Open Access Journals (Sweden)

    Shohei Sakuda

    2014-03-01

    Full Text Available Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control.

  18. Inhibitory Effects of Respiration Inhibitors on Aflatoxin Production

    Science.gov (United States)

    Sakuda, Shohei; Prabowo, Diyan Febri; Takagi, Keiko; Shiomi, Kazuro; Mori, Mihoko; Ōmura, Satoshi; Nagasawa, Hiromichi

    2014-01-01

    Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A) inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III) and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control. PMID:24674936

  19. Acalabrutinib (ACP-196: a selective second-generation BTK inhibitor

    Directory of Open Access Journals (Sweden)

    Jingjing Wu

    2016-03-01

    Full Text Available Abstract More and more targeted agents become available for B cell malignancies with increasing precision and potency. The first-in-class Bruton’s tyrosine kinase (BTK inhibitor, ibrutinib, has been in clinical use for the treatment of chronic lymphocytic leukemia, mantle cell lymphoma, and Waldenstrom’s macroglobulinemia. More selective BTK inhibitors (ACP-196, ONO/GS-4059, BGB-3111, CC-292 are being explored. Acalabrutinib (ACP-196 is a novel irreversible second-generation BTK inhibitor that was shown to be more potent and selective than ibrutinib. This review summarized the preclinical research and clinical data of acalabrutinib.

  20. Advances toward multifunctional cholinesterase and β-amyloid aggregation inhibitors.

    Science.gov (United States)

    Panek, Dawid; Wichur, Tomasz; Godyń, Justyna; Pasieka, Anna; Malawska, Barbara

    2017-10-01

    The emergence of a multitarget design approach in the development of new potential anti-Alzheimer's disease agents has resulted in the discovery of many multifunctional compounds focusing on various targets. Among them the largest group comprises inhibitors of both cholinesterases, with additional anti-β-amyloid aggregation activity. This review describes recent advances in this research area and presents the most interesting compounds reported over a 2-year span (2015-2016). The majority of hybrids possess heterodimeric structures obtained by linking structurally active fragments interacting with different targets. Multipotent cholinesterase inhibitors with β-amyloid antiaggregating activity may additionally possess antioxidative, neuroprotective or metal-chelating properties or less common features such as anti-β-secretase or τ-antiaggregation activity.

  1. Predictive modeling of EEG time series for evaluating surgery targets in epilepsy patients.

    Science.gov (United States)

    Steimer, Andreas; Müller, Michael; Schindler, Kaspar

    2017-05-01

    During the last 20 years, predictive modeling in epilepsy research has largely been concerned with the prediction of seizure events, whereas the inference of effective brain targets for resective surgery has received surprisingly little attention. In this exploratory pilot study, we describe a distributional clustering framework for the modeling of multivariate time series and use it to predict the effects of brain surgery in epilepsy patients. By analyzing the intracranial EEG, we demonstrate how patients who became seizure free after surgery are clearly distinguished from those who did not. More specifically, for 5 out of 7 patients who obtained seizure freedom (= Engel class I) our method predicts the specific collection of brain areas that got actually resected during surgery to yield a markedly lower posterior probability for the seizure related clusters, when compared to the resection of random or empty collections. Conversely, for 4 out of 5 Engel class III/IV patients who still suffer from postsurgical seizures, performance of the actually resected collection is not significantly better than performances displayed by random or empty collections. As the number of possible collections ranges into billions and more, this is a substantial contribution to a problem that today is still solved by visual EEG inspection. Apart from epilepsy research, our clustering methodology is also of general interest for the analysis of multivariate time series and as a generative model for temporally evolving functional networks in the neurosciences and beyond. Hum Brain Mapp 38:2509-2531, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  2. Pathophysiological significance and therapeutic applications of snake venom protease inhibitors.

    Science.gov (United States)

    Thakur, Rupamoni; Mukherjee, Ashis K

    2017-06-01

    Protease inhibitors are important constituents of snake venom and play important roles in the pathophysiology of snakebite. Recently, research on snake venom protease inhibitors has provided valuable information to decipher the molecular details of various biological processes and offer insight for the development of some therapeutically important molecules from snake venom. The process of blood coagulation and fibrinolysis, in addition to affecting platelet function, are well known as the major targets of several snake venom protease inhibitors. This review summarizes the structure-functional aspects of snake venom protease inhibitors that have been described to date. Because diverse biological functions have been demonstrated by protease inhibitors, a comparative overview of their pharmacological and pathophysiological properties is also highlighted. In addition, since most snake venom protease inhibitors are non-toxic on their own, this review evaluates the different roles of individual protease inhibitors that could lead to the identification of drug candidates and diagnostic molecules. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Novel nonpeptidic inhibitors of peptide deformylase.

    Science.gov (United States)

    Jayasekera, M M; Kendall, A; Shammas, R; Dermyer, M; Tomala, M; Shapiro, M A; Holler, T P

    2000-09-15

    A novel series of nonpeptidic compounds structurally related to the known anticholesteremic thyropropic acid were found to inhibit Escherichia coli peptide deformylase (PDF), with IC50 values in the low-micromolar range. Kinetic analysis of [4-(4-hydroxyphenoxy)-3,5-diiodophenyl]acetic acid reveals competitive inhibition, with a Ki value of 0.66 +/- 0.007 microM. A structure-activity relationship study demonstrates that the carboxylate is required for activity, while the distal phenolic function can be methylated without significant effect. Either decreasing the number of iodine atoms on the molecule to one or increasing the number of iodine atoms to four results in the loss of an order of magnitude in potency. These compounds are the first nonpeptidic inhibitors disclosed and represent a template from which better inhibitors might be designed.

  4. Sodium-glucose cotransporter 2 inhibitors combined with dipeptidyl peptidase-4 inhibitors in the management of type 2 diabetes: a review of current clinical evidence and rationale

    Directory of Open Access Journals (Sweden)

    Yassin SA

    2017-03-01

    Full Text Available Sayf A Yassin,1 Vanita R Aroda2 1MedStar Union Memorial Hospital, Baltimore, 2MedStar Health Research Institute, Hyattsville, MD, USA Abstract: Type 2 diabetes mellitus (T2DM is a progressive and multifactorial cardiometabolic disorder. Almost half of adults with diabetes fail to achieve their recommended glucose control target. This has prompted some clinicians to advocate the use of more intensive initial therapy, including the use of combination therapy to target multiple physiologic defects in diabetes with the goal of achieving and sustaining glucose control. Numerous options exist for combining the various classes of glucose-lowering agents in the treatment of T2DM. This report reviews the mechanism, rationale, and evidence from clinical trials for combining two of the newer drug classes, namely, dipeptidyl peptidase-4 inhibitors and sodium-glucose cotransporter 2 inhibitors, and considers the possible role of such dual therapy in the management of T2DM. Keywords: sodium-glucose cotransporter 2 inhibitors, dipeptidyl peptidase-4 inhibitors, type 2 diabetes mellitus, combination therapy

  5. Substrate-derived triazolo- and azapeptides as inhibitors of cathepsins K and S.

    Science.gov (United States)

    Galibert, Matthieu; Wartenberg, Mylène; Lecaille, Fabien; Saidi, Ahlame; Mavel, Sylvie; Joulin-Giet, Alix; Korkmaz, Brice; Brömme, Dieter; Aucagne, Vincent; Delmas, Agnès F; Lalmanach, Gilles

    2018-01-20

    Cathepsin (Cat) K is a critical bone-resorbing protease and is a relevant target for the treatment of osteoporosis and bone metastasis, while CatS is an attractive target for drugs in autoimmune diseases (e.g. rheumatoid arthritis), emphysema or neuropathic pain. Despite major achievements, current pharmacological inhibitors are still lacking in safety and may have damaging side effects. A promising strategy for developing safer reversible and competitive inhibitors as new lead compounds could be to insert non-cleavable bonds at the scissile P1-P1' position of selective substrates of CatS and CatK. Accordingly, we introduced a 1,4-disubstituted 1,2,3-triazole heterocycle that mimics most of the features of a trans-amide bond, or we incorporated a semicarbazide bond (azaGly residue) by replacing the α-carbon of the glycyl residue at P1 by a nitrogen atom. AzaGly-containing peptidomimetics inhibited powerfully their respective target proteases in the nM range, while triazolopeptides were weaker inhibitors (Ki in the μM range). The selectivity of the azaGly CatS inhibitor (1b) was confirmed by using spleen lysates from wild-type vs CatS-deficient mice. Alternatively, the azaGly bradykinin-derived CatK inhibitor (2b) potently inhibited CatK (Ki = 9 nM) and impaired its kininase activity in vitro. Molecular modeling studies support that the semicarbazide bond of 2b is more favorable than the 1,2,3-triazole linkage of the bradykinin-derived pseudopeptide 2a to preserve an effective affinity towards CatK, its protease target. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  6. Targeting Signaling Pathways in Epithelial Ovarian Cancer

    Directory of Open Access Journals (Sweden)

    Johannes Haybaeck

    2013-05-01

    Full Text Available Ovarian carcinoma (OC is the most lethal gynecological malignancy. Response to platinum-based chemotherapy is poor in some patients and, thus, current research is focusing on new therapy options. The various histological types of OC are characterized by distinctive molecular genetic alterations that are relevant for ovarian tumorigenesis. The understanding of these molecular pathways is essential for the development of novel therapeutic strategies. Purpose: We want to give an overview on the molecular genetic changes of the histopathological types of OC and their role as putative therapeutic targets. In Depth Review of Existing Data: In 2012, the vascular endothelial growth factor (VEGF inhibitor, bevacizumab, was approved for OC treatment. Bevacizumab has shown promising results as single agent and in combination with conventional chemotherapy, but its target is not distinctive when analyzed before treatment. At present, mammalian target of rapamycin (mTOR inhibitors, poly-ADP-ribose polymerase (PARP inhibitors and components of the EGFR pathway are in the focus of clinical research. Interestingly, some phytochemical substances show good synergistic effects when used in combination with chemotherapy. Conclusion: Ongoing studies of targeted agents in conjunction with chemotherapy will show whether there are alternative options to bevacizumab available for OC patients. Novel targets which can be assessed before therapy to predict efficacy are needed. The assessment of therapeutic targets is continuously improved by molecular pathological analyses on tumor tissue. A careful selection of patients for personalized treatment will help to reduce putative side effects and toxicity.

  7. Pre-equilibrium competitive library screening for tuning inhibitor association rate and specificity toward serine proteases.

    Science.gov (United States)

    Cohen, Itay; Naftaly, Si; Ben-Zeev, Efrat; Hockla, Alexandra; Radisky, Evette S; Papo, Niv

    2018-04-16

    High structural and sequence similarity within protein families can pose significant challenges to the development of selective inhibitors, especially toward proteolytic enzymes. Such enzymes usually belong to large families of closely similar proteases and may also hydrolyze, with different rates, protein- or peptide-based inhibitors. To address this challenge, we employed a combinatorial yeast surface display library approach complemented with a novel pre-equilibrium, competitive screening strategy for facile assessment of the effects of multiple mutations on inhibitor association rates and binding specificity. As a proof of principle for this combined approach, we utilized this strategy to alter inhibitor/protease association rates and to tailor the selectivity of the amyloid β-protein precursor Kunitz protease inhibitor domain (APPI) for inhibition of the oncogenic protease mesotrypsin, in the presence of three competing serine proteases, anionic trypsin, cationic trypsin and kallikrein-6. We generated a variant, designated APPI P13W/M17G/I18F/F34V , with up to 30-fold greater specificity relative to the parental APPI M17G/I18F/F34V protein, and 6500- to 230 000-fold improved specificity relative to the wild-type APPI protein in the presence of the other proteases tested. A series of molecular docking simulations suggested a mechanism of interaction that supported the biochemical results. These simulations predicted that the selectivity and specificity are affected by the interaction of the mutated APPI residues with nonconserved enzyme residues located in or near the binding site. Our strategy will facilitate a better understanding of the binding landscape of multispecific proteins and will pave the way for design of new drugs and diagnostic tools targeting proteases and other proteins. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  8. Structural Characterization of LRRK2 Inhibitors

    NARCIS (Netherlands)

    Gilsbach, Bernd K; Messias, Ana C; Ito, Genta; Sattler, Michael; Alessi, Dario R; Wittinghofer, Alfred; Kortholt, Arjan

    2015-01-01

    Kinase inhibition is considered to be an important therapeutic target for LRRK2 mediated Parkinson's disease (PD). Many LRRK2 kinase inhibitors have been reported but have yet to be optimized in order to qualify as drug candidates for the treatment of the disease. In order to start a

  9. Interaction of HIV-1 reverse transcriptase ribonuclease H with an acylhydrazone inhibitor.

    Science.gov (United States)

    Gong, Qingguo; Menon, Lakshmi; Ilina, Tatiana; Miller, Lena G; Ahn, Jinwoo; Parniak, Michael A; Ishima, Rieko

    2011-01-01

    HIV-1 reverse transcriptase is a bifunctional enzyme, having both DNA polymerase (RNA- and DNA-dependent) and ribonuclease H activities. HIV-1 reverse transcriptase has been an exceptionally important target for antiretroviral therapeutic development, and nearly half of the current clinically used antiretrovirals target reverse transcriptase DNA polymerase. However, no inhibitors of reverse transcriptase ribonuclease H are on the market or in preclinical development. Several drug-like small molecule inhibitors of reverse transcriptase ribonuclease H have been described, but little structural information is available about the interactions between reverse transcriptase ribonuclease H and inhibitors that exhibit antiviral activity. In this report, we describe NMR studies of the interaction of a new ribonuclease H inhibitor, BHMP07, with a catalytically active HIV-1 reverse transcriptase ribonuclease H domain fragment. We carried out solution NMR experiments to identify the interaction interface of BHMP07 with the ribonuclease H domain fragment. Chemical shift changes of backbone amide signals at different BHMP07 concentrations clearly demonstrate that BHMP07 mainly recognizes the substrate handle region in the ribonuclease H fragment. Using ribonuclease H inhibition assays and reverse transcriptase mutants, the binding specificity of BHMP07 was compared with another inhibitor, dihydroxy benzoyl naphthyl hydrazone. Our results provide a structural characterization of the ribonuclease H inhibitor interaction and are likely to be useful for further improvements of the inhibitors. © 2010 John Wiley & Sons A/S.

  10. A bioavailable cathepsin S nitrile inhibitor abrogates tumor development.

    Science.gov (United States)

    Wilkinson, Richard D A; Young, Andrew; Burden, Roberta E; Williams, Rich; Scott, Christopher J

    2016-04-21

    Cathepsin S has been implicated in a variety of malignancies with genetic ablation studies demonstrating a key role in tumor invasion and neo-angiogenesis. Thus, the application of cathepsin S inhibitors may have clinical utility in the treatment of cancer. In this investigation, we applied a cell-permeable dipeptidyl nitrile inhibitor of cathepsin S, originally developed to target cathepsin S in inflammatory diseases, in both in vitro and in vivo tumor models. Validation of cathepsin S selectivity was carried out by assaying fluorogenic substrate turnover using recombinant cathepsin protease. Complete kinetic analysis was carried out and true K i values calculated. Abrogation of tumour invasion using murine MC38 and human MCF7 cell lines were carried out in vitro using a transwell migration assay. Effect on endothelial tube formation was evaluated using primary HUVEC cells. The effect of inhibitor in vivo on MC38 and MCF7 tumor progression was evaluated using cells propagated in C57BL/6 and BALB/c mice respectively. Subsequent immunohistochemical staining of proliferation (Ki67) and apoptosis (TUNEL) was carried out on MCF7 tumors. We confirmed that this inhibitor was able to selectively target cathepsin S over family members K, V, L and B. The inhibitor also significantly reduced MC38 and MCF7 cell invasion and furthermore, significantly reduced HUVEC endothelial tubule formation in vitro. In vivo analysis revealed that the compound could significantly reduce tumor volume in murine MC38 syngeneic and MCF7 xenograft models. Immunohistochemical analysis of MCF7 tumors revealed cathepsin S inhibitor treatment significantly reduced proliferation and increased apoptosis. In summary, these results highlight the characterisation of this nitrile cathepsin S inhibitor using in vitro and in vivo tumor models, presenting a compound which may be used to further dissect the role of cathepsin S in cancer progression and may hold therapeutic potential.

  11. The discovery of glycine and related amino acid-based factor Xa inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Kohrt, Jeffrey T.; Filipski, Kevin J.; Cody, Wayne L.; Bigge, Christopher F.; La, Frances; Welch, Kathleen; Dahring, Tawny; Bryant, John W.; Leonard, Daniele; Bolton, Gary; Narasimhan, Lakshmi; Zhang, Erli; Peterson, J. Thomas; Haarer, Staci; Sahasrabudhe, Vaishali; Janiczek, Nancy; Desiraju, Shrilakshmi; Hena, Mostofa; Fiakpui, Charles; Saraswat, Neerja; Sharma, Raman; Sun, Shaoyi; Maiti, Samarendra N.; Leadley, Robert; Edmunds, Jeremy J. (Naeja); (Pfizer)

    2010-12-03

    Herein, we report on the identification of three potent glycine and related amino acid-based series of FXa inhibitors containing a neutral P1 chlorophenyl pharmacophore. A X-ray crystal structure has shown that constrained glycine derivatives with optimized N-substitution can greatly increase hydrophobic interactions in the FXa active site. Also, the substitution of a pyridone ring for a phenylsulfone ring in the P4 sidechain resulted in an inhibitor with enhanced oral bioavailability.

  12. Recent Advances in the Development and Application of Radiolabeled Kinase Inhibitors for PET Imaging

    Directory of Open Access Journals (Sweden)

    Vadim Bernard-Gauthier

    2015-12-01

    Full Text Available Over the last 20 years, intensive investigation and multiple clinical successes targeting protein kinases, mostly for cancer treatment, have identified small molecule kinase inhibitors as a prominent therapeutic class. In the course of those investigations, radiolabeled kinase inhibitors for positron emission tomography (PET imaging have been synthesized and evaluated as diagnostic imaging probes for cancer characterization. Given that inhibitor coverage of the kinome is continuously expanding, in vivo PET imaging will likely find increasing applications for therapy monitoring and receptor density studies both in- and outside of oncological conditions. Early investigated radiolabeled inhibitors, which are mostly based on clinically approved tyrosine kinase inhibitor (TKI isotopologues, have now entered clinical trials. Novel radioligands for cancer and PET neuroimaging originating from novel but relevant target kinases are currently being explored in preclinical studies. This article reviews the literature involving radiotracer design, radiochemistry approaches, biological tracer evaluation and nuclear imaging results of radiolabeled kinase inhibitors for PET reported between 2010 and mid-2015. Aspects regarding the usefulness of pursuing selective vs. promiscuous inhibitor scaffolds and the inherent challenges associated with intracellular enzyme imaging will be discussed.

  13. Synthesis and Evaluation of the Tumor Cell Growth Inhibitory Potential of New Putative HSP90 Inhibitors.

    Science.gov (United States)

    Bizarro, Ana; Sousa, Diana; Lima, Raquel T; Musso, Loana; Cincinelli, Raffaella; Zuco, Vantina; De Cesare, Michelandrea; Dallavalle, Sabrina; Vasconcelos, M Helena

    2018-02-13

    Heat shock protein 90 (HSP90) is a well-known target for cancer therapy. In a previous work, some of us have reported a series of 3-aryl-naphtho[2,3- d ]isoxazole-4,9-diones as inhibitors of HSP90. In the present work, various compounds with new chromenopyridinone and thiochromenopyridinone scaffolds were synthesized as potential HSP90 inhibitors. Their binding affinity to HSP90 was studied in vitro. Selected compounds ( 5 and 8 ) were further studied in various tumor cell lines regarding their potential to cause cell growth inhibition, alter the cell cycle profile, inhibit proliferation, and induce apoptosis. Their effect on HSP90 client protein levels was also confirmed in two cell lines. Finally, the antitumor activity of compound 8 was studied in A431 squamous cell carcinoma xenografts in nude mice. Our results indicated that treatment with compounds 5 and 8 decreased the proliferation of tumor cell lines and compound 8 induced apoptosis. In addition, these two compounds were able to downregulate selected proteins known as "clients" of HSP90. Finally, treatment of xenografted mice with compound 5 resulted in a considerable dose-dependent inhibition of tumor growth. Our results show that two new compounds with a chromenopyridinone and thiochromenopyridinone scaffold are promising putative HSP90 inhibitors causing tumor cell growth inhibition.

  14. Design and Testing of Bi-Functional, P-Loop-Targeted MDM2 Inhibitors

    National Research Council Canada - National Science Library

    Prives, Carol L; Stockwell, Brent R

    2007-01-01

    Our proposal is to design and evaluate a novel class of bifunctional MDM2 inhibitors, based on the discovery that nucleotides can bind to the P-loop of MDM2 and cause its relocalization to the nucleolus...

  15. Design and Testing of Bi-Functional, P-Loop-Targeted MDM2 Inhibitors

    National Research Council Canada - National Science Library

    Prives, Carol L

    2006-01-01

    This proposal is to design and evaluate a novel class of bifunctional MDM2 inhibitors, based on the discovery that nucleotides can bind to the P-loop of MDM2 and cause its relocalization to the nucleolus...

  16. HIV protease drug resistance and its impact on inhibitor design.

    Science.gov (United States)

    Ala, P J; Rodgers, J D; Chang, C H

    1999-07-01

    The primary cause of resistance to the currently available HIV protease inhibitors is the accumulation of multiple mutations in the viral protease. So far more than 20 substitutions have been observed in the active site, dimer interface, surface loops and flaps of the homodimer. While many mutations reduce the protease's affinity for inhibitors, others appear to enhance its catalytic efficiency. This high degree of genetic flexibility has made the protease an elusive drug target. The design of the next generation of HIV protease inhibitors will be discussed in light of the current structural information.

  17. Bacillus anthracis o-succinylbenzoyl-CoA synthetase: reaction kinetics and a novel inhibitor mimicking its reaction intermediate †

    Science.gov (United States)

    Tian, Yang; Suk, Dae-Hwan; Cai, Feng; Crich, David; Mesecar, Andrew D.

    2009-01-01

    O-succinylbenzoyl-CoA (OSB-CoA) synthetase (EC 6.2.1.26) catalyzes the ATP-dependent condensation of o-succinylbenzoate (OSB) and CoA to form OSB-CoA, the fourth step of the menaquinone biosynthetic pathway in Bacillus anthracis. Gene knockout studies have highlighted this enzyme as a potential target for the discovery of new antibiotics. Here we report the first studies on the kinetic mechanism of B. anthracis OSB-CoA synthetase, classifying it as an ordered Bi Uni Uni Bi ping-pong mechanism. Through a series of pre-steady-state and steady-state kinetic studies in conjunction with direct-binding studies, it is demonstrated that CoA, the last substrate to bind, strongly activates the first half-reaction after the first round of turnover. The activation of the first-half reaction is most likely achieved by CoA stabilizing conformations of the enzyme in the ‘F’ form, which slowly isomerize back to the E form. Thus, the kinetic mechanism of OSB-CoA synthetase may be more accurately described as an ordered Bi Uni Uni Bi Iso ping-pong mechanism. The substrate specificity of OSB-CoA synthetase was probed using a series of OSB analogs with alterations in the carboxylate groups. OSB-CoA shows a strong preference for OSB over all of the analogs tested as none were active except 4-(2-trifluoromethylphenyl)-4-oxobutyric acid which exhibited a 100-fold decrease in kcat/Km. Based on an understanding of OSB-CoA synthetase’s kinetic mechanism and substrate specificity, a reaction intermediate analog of OSB-AMP, 5’-O-(N-(2-trifluoromethylphenyl)-4-oxobutyl) adenosine sulfonamide (TFMP-butyl-AMS), was designed and synthesized. This inhibitor was found to be an uncompetitive inhibitor to CoA and a mixed-type inhibitor to ATP and OSB with low micromolar inhibition constants. Collectively, these results should serve as an important forerunner to more detailed and extensive inhibitor design studies aimed at developing lead compounds against the OSB-CoA synthetase class of

  18. Targeted therapies in the treatment of urothelial cancers.

    Science.gov (United States)

    Aragon-Ching, Jeanny B; Trump, Donald L

    2017-07-01

    Progress has been slow in systemic management of locally advanced and metastatic bladder cancer over the past 20 years. However, the recent approval of immunotherapy with atezolizumab and nivolumab for second-line salvage therapy may usher in an era of more rapid improvement. Systemic treatment is suboptimal and is an area of substantial unmet medical need. The recent findings from The Cancer Genome Atlas project revealed promising pathways that may be amenable to targeted therapies. Promising results with treatment using vascular endothelial growth factor inhibitors such as ramucirumab, sunitinib or bevacizumab, and human epidermal growth factor receptor 2 targeted therapies, epidermal growth factor receptor inhibitors, and fibroblast growth factor receptor inhibitors, are undergoing clinical trials and are discussed later. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Inhibitors of Microglial Neurotoxicity: Focus on Natural Products

    Directory of Open Access Journals (Sweden)

    Kyoungho Suk

    2011-01-01

    Full Text Available Microglial cells play a dual role in the central nervous system as they have both neurotoxic and neuroprotective effects. Uncontrolled and excessive activation of microglia often contributes to inflammation-mediated neurodegeneration. Recently, much attention has been paid to therapeutic strategies aimed at inhibiting neurotoxic microglial activation. Pharmacological inhibitors of microglial activation are emerging as a result of such endeavors. In this review, natural products-based inhibitors of microglial activation will be reviewed. Potential neuroprotective activity of these compounds will also be discussed. Future works should focus on the discovery of novel drug targets that specifically mediate microglial neurotoxicity rather than neuroprotection. Development of new drugs based on these targets may require a better understanding of microglial biology and neuroinflammation at the molecular, cellular, and systems levels.

  20. Synergistic Malaria Parasite Killing by Two Types of Plasmodial Surface Anion Channel Inhibitors.

    Directory of Open Access Journals (Sweden)

    Margaret Pain

    Full Text Available Malaria parasites increase their host erythrocyte's permeability to a broad range of ions and organic solutes. The plasmodial surface anion channel (PSAC mediates this uptake and is an established drug target. Development of therapies targeting this channel is limited by several problems including interactions between known inhibitors and permeating solutes that lead to incomplete channel block. Here, we designed and executed a high-throughput screen to identify a novel class of PSAC inhibitors that overcome this solute-inhibitor interaction. These new inhibitors differ from existing blockers and have distinct effects on channel-mediated transport, supporting a model of two separate routes for solute permeation though PSAC. Combinations of inhibitors specific for the two routes had strong synergistic action against in vitro parasite propagation, whereas combinations acting on a single route produced only additive effects. The magnitude of synergism depended on external nutrient concentrations, consistent with an essential role of the channel in parasite nutrient acquisition. The identified inhibitors will enable a better understanding of the channel's structure-function and may be starting points for novel combination therapies that produce synergistic parasite killing.

  1. Structure-activity relationships of amide-phosphonate derivatives as inhibitors of the human soluble epoxide hydrolase.

    Science.gov (United States)

    Kim, In-Hae; Park, Yong-Kyu; Nishiwaki, Hisashi; Hammock, Bruce D; Nishi, Kosuke

    2015-11-15

    Structure-activity relationships of amide-phosphonate derivatives as inhibitors of the human soluble epoxide hydrolase (sEH) were investigated. First, a series of alkyl or aryl groups were substituted on the carbon alpha to the phosphonate function in amide compounds to see whether substituted phosphonates can act as a secondary pharmacophore. A tert-butyl group (16) on the alpha carbon was found to yield most potent inhibition on the target enzyme. A 4-50-fold drop in inhibition was induced by other substituents such as aryls, substituted aryls, cycloalkyls, and alkyls. Then, the modification of the O-substituents on the phosphonate function revealed that diethyl groups (16 and 23) were preferable for inhibition to other longer alkyls or substituted alkyls. In amide compounds with the optimized diethylphosphonate moiety and an alkyl substitution such as adamantane (16), tetrahydronaphthalene (31), or adamantanemethane (36), highly potent inhibitions were gained. In addition, the resulting potent amide-phosphonate compounds had reasonable water solubility, suggesting that substituted phosphonates in amide inhibitors are effective for both inhibition potency on the human sEH and water solubility as a secondary pharmacophore. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Homology modeling, molecular dynamics and inhibitor binding study on MurD ligase of Mycobacterium tuberculosis.

    Science.gov (United States)

    Arvind, Akanksha; Kumar, Vivek; Saravanan, Parameswaran; Mohan, C Gopi

    2012-09-01

    The cell wall of mycobacterium offers well validated targets which can be exploited for discovery of new lead compounds. MurC-MurF ligases catalyze a series of irreversible steps in the biosynthesis of peptidoglycan precursor, i.e. MurD catalyzes the ligation of D-glutamate to the nucleotide precursor UMA. The three dimensional structure of Mtb-MurD is not known and was predicted by us for the first time using comparative homology modeling technique. The accuracy and stability of the predicted Mtb-MurD structure was validated using Procheck and molecular dynamics simulation. Key interactions in Mtb-MurD were studied using docking analysis of available transition state inhibitors of E.coli-MurD. The docking analysis revealed that analogues of both L and D forms of glutamic acid have similar interaction profiles with Mtb-MurD. Further, residues His192, Arg382, Ser463, and Tyr470 are proposed to be important for inhibitor-(Mtb-MurD) interactions. We also identified few pharmacophoric features essential for Mtb-MurD ligase inhibitory activity and which can further been utilized for the discovery of putative antitubercular chemotherapy.

  3. A Novel, Broad-Spectrum Inhibitor of Enterovirus Replication That Targets Host Cell Factor Phosphatidylinositol 4-Kinase IIIβ

    Science.gov (United States)

    van der Schaar, Hilde M.; Leyssen, Pieter; Thibaut, Hendrik J.; de Palma, Armando; van der Linden, Lonneke; Lanke, Kjerstin H. W.; Lacroix, Céline; Verbeken, Erik; Conrath, Katja; MacLeod, Angus M.; Mitchell, Dale R.; Palmer, Nicholas J.; van de Poël, Hervé; Andrews, Martin

    2013-01-01

    Despite their high clinical and socioeconomic impacts, there is currently no approved antiviral therapy for the prophylaxis or treatment of enterovirus infections. Here we report on a novel inhibitor of enterovirus replication, compound 1, 2-fluoro-4-(2-methyl-8-(3-(methylsulfonyl)benzylamino)imidazo[1,2-a]pyrazin-3-yl)phenol. This compound exhibited a broad spectrum of antiviral activity, as it inhibited all tested species of enteroviruses and rhinoviruses, with 50% effective concentrations ranging between 4 and 71 nM. After a lengthy resistance selection process, coxsackievirus mutants resistant to compound 1 were isolated that carried substitutions in their 3A protein. Remarkably, the same substitutions were recently shown to provide resistance to inhibitors of phosphatidylinositol 4-kinase IIIβ (PI4KIIIβ), a lipid kinase that is essential for enterovirus replication, suggesting that compound 1 may also target this host factor. Accordingly, compound 1 directly inhibited PI4KIIIβ in an in vitro kinase activity assay. Furthermore, the compound strongly reduced the PI 4-phosphate levels of the Golgi complex in cells. Rescue of coxsackievirus replication in the presence of compound 1 by a mutant PI4KIIIβ carrying a substitution in its ATP-binding pocket revealed that the compound directly binds the kinase at this site. Finally, we determined that an analogue of compound 1, 3-(3-fluoro-4-methoxyphenyl)-2-methyl-N-(pyridin-4-ylmethyl)imidazo[1,2-a]pyrazin-8-amine, is well tolerated in mice and has a dose-dependent protective activity in a coxsackievirus serotype B4-induced pancreatitis model. PMID:23896472

  4. Recent advances in the discovery of small molecule c-Met Kinase inhibitors.

    Science.gov (United States)

    Parikh, Palak K; Ghate, Manjunath D

    2018-01-01

    c-Met is a prototype member of a subfamily of heterodimeric receptor tyrosine kinases (RTKs) and is the receptor for hepatocyte growth factor (HGF). Binding of HGF to its receptor c-Met, initiates a wide range of cellular signalling, including those involved in proliferation, motility, migration and invasion. Importantly, dysregulated HGF/c-Met signalling is a driving factor for numerous malignancies and promotes tumour growth, invasion, dissemination and/or angiogenesis. Dysregulated HGF/c-Met signalling has also been associated with poor clinical outcomes and resistance acquisition to some approved targeted therapies. Thus, c-Met kinase has emerged as a promising target for cancer drug development. Different therapeutic approaches targeting the HGF/c-Met signalling pathway are under development for targeted cancer therapy, among which small molecule inhibitors of c-Met kinase constitute the largest effort within the pharmaceutical industry. The review is an effort to summarize recent advancements in medicinal chemistry development of small molecule c-Met kinase inhibitors as potential anti-cancer agents which would certainly help future researchers to bring further developments in the discovery of small molecule c-Met kinase inhibitors. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  5. Elaboration of a fragment library hit produces potent and selective aspartate semialdehyde dehydrogenase inhibitors.

    Science.gov (United States)

    Thangavelu, Bharani; Bhansali, Pravin; Viola, Ronald E

    2015-10-15

    Aspartate-β-semialdehyde dehydrogenase (ASADH) lies at the first branch point in the aspartate metabolic pathway which leads to the biosynthesis of several essential amino acids and some important metabolites. This pathway is crucial for many metabolic processes in plants and microbes like bacteria and fungi, but is absent in mammals. Therefore, the key microbial enzymes involved in this pathway are attractive potential targets for development of new antibiotics with novel modes of action. The ASADH enzyme family shares the same substrate binding and active site catalytic groups; however, the enzymes from representative bacterial and fungal species show different inhibition patterns when previously screened against low molecular weight inhibitors identified from fragment library screening. In the present study several approaches, including fragment based drug discovery (FBDD), inhibitor docking, kinetic, and structure-activity relationship (SAR) studies have been used to guide ASADH inhibitor development. Elaboration of a core structure identified by FBDD has led to the synthesis of low micromolar inhibitors of the target enzyme, with high selectivity introduced between the Gram-negative and Gram-positive orthologs of ASADH. This new set of structures open a novel direction for the development of inhibitors against this validated drug-target enzyme. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Plasma tissue inhibitor of metalloproteinases-1 as a biological marker?

    DEFF Research Database (Denmark)

    Lomholt, Anne F.; Frederiksen, Camilla B.; Christensen, Ib J.

    2007-01-01

    Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) may be a valuable biological marker in Colorectal Cancer (CRC). However, prospective validation of TIMP-1 as a biological marker should include a series of pre-analytical considerations. TIMP-1 is stored in platelets, which may degranulate during...

  7. Validation of tautomeric and protomeric binding modes by free energy calculations. A case study for the structure based optimization of d-amino acid oxidase inhibitors

    Science.gov (United States)

    Orgován, Zoltán; Ferenczy, György G.; Steinbrecher, Thomas; Szilágyi, Bence; Bajusz, Dávid; Keserű, György M.

    2018-02-01

    Optimization of fragment size d-amino acid oxidase (DAAO) inhibitors was investigated using a combination of computational and experimental methods. Retrospective free energy perturbation (FEP) calculations were performed for benzo[d]isoxazole derivatives, a series of known inhibitors with two potential binding modes derived from X-ray structures of other DAAO inhibitors. The good agreement between experimental and computed binding free energies in only one of the hypothesized binding modes strongly support this bioactive conformation. Then, a series of 1-H-indazol-3-ol derivatives formerly not described as DAAO inhibitors was investigated. Binding geometries could be reliably identified by structural similarity to benzo[d]isoxazole and other well characterized series and FEP calculations were performed for several tautomers of the deprotonated and protonated compounds since all these forms are potentially present owing to the experimental pKa values of representative compounds in the series. Deprotonated compounds are proposed to be the most important bound species owing to the significantly better agreement between their calculated and measured affinities compared to the protonated forms. FEP calculations were also used for the prediction of the affinities of compounds not previously tested as DAAO inhibitors and for a comparative structure-activity relationship study of the benzo[d]isoxazole and indazole series. Selected indazole derivatives were synthesized and their measured binding affinity towards DAAO was in good agreement with FEP predictions.

  8. Big enough for an aromatase inhibitor? How adiposity affects male fertility.

    Science.gov (United States)

    Stephens, Sahar M; Polotsky, Alex J

    2013-07-01

    Obesity is a pandemic and is associated with multiple medical problems including subfertility. Male obesity has been associated with altered semen parameters and reproductive hormonal levels, including a reduced testosterone:estradiol (T:E₂) ratio. Treatment methods employed for obesity-related male subfertility include gonadotropin administration, weight loss, and aromatase inhibitors. Letrozole is a highly effective nonsteroidal aromatase inhibitor that has been used to treat male subfertility in several case series with promising results. Adequately designed randomized controlled studies are needed to produce evidence-based data on the role of aromatase inhibitors in male subfertility management and evaluate the side-effect profile. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  9. ROMK inhibitor actions in the nephron probed with diuretics.

    Science.gov (United States)

    Kharade, Sujay V; Flores, Daniel; Lindsley, Craig W; Satlin, Lisa M; Denton, Jerod S

    2016-04-15

    Diuretics acting on specific nephron segments to inhibit Na + reabsorption have been used clinically for decades; however, drug interactions, tolerance, and derangements in serum K + complicate their use to achieve target blood pressure. ROMK is an attractive diuretic target, in part, because its inhibition is postulated to indirectly inhibit the bumetanide-sensitive Na + -K + -2Cl - cotransporter (NKCC2) and the amiloride- and benzamil-sensitive epithelial Na + channel (ENaC). The development of small-molecule ROMK inhibitors has created opportunities for exploring the physiological responses to ROMK inhibition. The present study evaluated how inhibition of ROMK alone or in combination with NKCC2, ENaC, or the hydrochlorothiazide (HCTZ) target NCC alter fluid and electrolyte transport in the nephron. The ROMK inhibitor VU591 failed to induce diuresis when administered orally to rats. However, another ROMK inhibitor, termed compound A, induced a robust natriuretic diuresis without kaliuresis. Compound A produced additive effects on urine output and Na + excretion when combined with HCTZ, amiloride, or benzamil, but not when coadministered with bumetanide, suggesting that the major diuretic target site is the thick ascending limb (TAL). Interestingly, compound A inhibited the kaliuretic response induced by bumetanide and HCTZ, an effect we attribute to inhibition of ROMK-mediated K + secretion in the TAL and CD. Compound A had no effect on heterologously expressed flow-sensitive large-conductance Ca 2+ -activated K + channels (Slo1/β1). In conclusion, compound A represents an important new pharmacological tool for investigating the renal consequences of ROMK inhibition and therapeutic potential of ROMK as a diuretic target. Copyright © 2016 the American Physiological Society.

  10. Discovery and antiplatelet activity of a selective PI3Kβ inhibitor (MIPS-9922).

    Science.gov (United States)

    Zheng, Zhaohua; Pinson, Jo-Anne; Mountford, Simon J; Orive, Stephanie; Schoenwaelder, Simone M; Shackleford, David; Powell, Andrew; Nelson, Erin M; Hamilton, Justin R; Jackson, Shaun P; Jennings, Ian G; Thompson, Philip E

    2016-10-21

    A series of amino-substituted triazines were developed and examined for PI3Kβ inhibition and anti-platelet function. Structural adaptations of a morpholine ring of the prototype pan-PI3K inhibitor ZSTK474 yielded PI3Kβ selective compounds, where the selectivity largely derives from an interaction with the non-conserved Asp862 residue, as shown by site directed mutagenesis. The most PI3Kβ selective inhibitor from the series was studied in detail through a series of in vitro and in vivo functional studies. MIPS-9922, 10 potently inhibited ADP-induced washed platelet aggregation. It also inhibited integrin αIIbβ3 activation and αIIbβ3 dependent platelet adhesion to immobilized vWF under high shear. It prevented arterial thrombus formation in the in vivo electrolytic mouse model of thrombosis without inducing prolonged bleeding or excess blood loss. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  11. Targeting Virus-host Interactions of HIV Replication.

    Science.gov (United States)

    Weydert, Caroline; De Rijck, Jan; Christ, Frauke; Debyser, Zeger

    2016-01-01

    Cellular proteins that are hijacked by HIV in order to complete its replication cycle, form attractive new targets for antiretroviral therapy. In particular, the protein-protein interactions between these cellular proteins (cofactors) and viral proteins are of great interest to develop new therapies. Research efforts have led to the validation of different cofactors and some successes in therapeutic applications. Maraviroc, the first cofactor inhibitor approved for human medicinal use, provided a proof of concept. Furthermore, compounds developed as Integrase-LEDGF/p75 interaction inhibitors (LEDGINs) have advanced to early clinical trials. Other compounds targeting cofactors and cofactor-viral protein interactions are currently under development. Likewise, interactions between cellular restriction factors and their counteracting HIV protein might serve as interesting targets in order to impair HIV replication. In this respect, compounds targeting the Vif-APOBEC3G interaction have been described. In this review, we focus on compounds targeting the Integrase- LEDGF/p75 interaction, the Tat-P-TEFb interaction and the Vif-APOBEC3G interaction. Additionally we give an overview of currently discovered compounds presumably targeting cellular cofactor-HIV protein interactions.

  12. Corrosion inhibitors for neutral aqueous media based on the products on sugar cane processing. 1.Furfural derivatives as inhibitors

    International Nuclear Information System (INIS)

    Ledovskikh, V.M.; Kamekho Khinnebra, Kh.Kh.

    1993-01-01

    A series of carboxy-, nitrogen- and nitroderivaties of furfural - the main product of sugar cane processing (furancasboxylic acid, 5-nitrofurancarboxylic acid and its salts, furfurine, furfurylamine) was studied as inhibitors of iron and copper, corrosion in aqueous-salt media. Nitrofuroates of sodium and ammonium, which decelerate anode process, intensity cathode one and provide the stable passive state, are considered to be the most effective

  13. Direct-acting antivirals and host-targeting strategies to combat enterovirus infections.

    Science.gov (United States)

    Bauer, Lisa; Lyoo, Heyrhyoung; van der Schaar, Hilde M; Strating, Jeroen Rpm; van Kuppeveld, Frank Jm

    2017-06-01

    Enteroviruses (e.g., poliovirus, enterovirus-A71, coxsackievirus, enterovirus-D68, rhinovirus) include many human pathogens causative of various mild and more severe diseases, especially in young children. Unfortunately, antiviral drugs to treat enterovirus infections have not been approved yet. Over the past decades, several direct-acting inhibitors have been developed, including capsid binders, which block virus entry, and inhibitors of viral enzymes required for genome replication. Capsid binders and protease inhibitors have been clinically evaluated, but failed due to limited efficacy or toxicity issues. As an alternative approach, host-targeting inhibitors with potential broad-spectrum activity have been identified. Furthermore, drug repurposing screens have recently uncovered promising new inhibitors with disparate viral and host targets. Together, these findings raise hope for the development of (broad-range) anti-enteroviral drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Microarray-based screening of heat shock protein inhibitors.

    Science.gov (United States)

    Schax, Emilia; Walter, Johanna-Gabriela; Märzhäuser, Helene; Stahl, Frank; Scheper, Thomas; Agard, David A; Eichner, Simone; Kirschning, Andreas; Zeilinger, Carsten

    2014-06-20

    Based on the importance of heat shock proteins (HSPs) in diseases such as cancer, Alzheimer's disease or malaria, inhibitors of these chaperons are needed. Today's state-of-the-art techniques to identify HSP inhibitors are performed in microplate format, requiring large amounts of proteins and potential inhibitors. In contrast, we have developed a miniaturized protein microarray-based assay to identify novel inhibitors, allowing analysis with 300 pmol of protein. The assay is based on competitive binding of fluorescence-labeled ATP and potential inhibitors to the ATP-binding site of HSP. Therefore, the developed microarray enables the parallel analysis of different ATP-binding proteins on a single microarray. We have demonstrated the possibility of multiplexing by immobilizing full-length human HSP90α and HtpG of Helicobacter pylori on microarrays. Fluorescence-labeled ATP was competed by novel geldanamycin/reblastatin derivatives with IC50 values in the range of 0.5 nM to 4 μM and Z(*)-factors between 0.60 and 0.96. Our results demonstrate the potential of a target-oriented multiplexed protein microarray to identify novel inhibitors for different members of the HSP90 family. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Potent and Selective Covalent Quinazoline Inhibitors of KRAS G12C

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Mei; Lu, Jia; Li, Lianbo; Feru, Frederic; Quan, Chunshan; Gero, Thomas W.; Ficarro, Scott B.; Xiong, Yuan; Ambrogio, Chiara; Paranal, Raymond M.; Catalano, Marco; Shao, Jay; Wong, Kwok-Kin; Marto, Jarrod A.; Fischer, Eric S.; Jänne, Pasi A.; Scott, David A.; Westover, Kenneth D.; Gray, Nathanael S. (DFCI); (UTSMC); (Harvard-Med); (NYUSM)

    2017-08-01

    Targeted covalent small molecules have shown promise for cancers driven by KRAS G12C. Allosteric compounds that access an inducible pocket formed by movement of a dynamic structural element in KRAS, switch II, have been reported, but these compounds require further optimization to enable their advancement into clinical development. We demonstrate that covalent quinazoline-based switch II pocket (SIIP) compounds effectively suppress GTP loading of KRAS G12C, MAPK phosphorylation, and the growth of cancer cells harboring G12C. Notably we find that adding an amide substituent to the quinazoline scaffold allows additional interactions with KRAS G12C, and remarkably increases the labeling efficiency, potency, and selectivity of KRAS G12C inhibitors. Structural studies using X-ray crystallography reveal a new conformation of SIIP and key interactions made by substituents located at the quinazoline 2-, 4-, and 7-positions. Optimized lead compounds in the quinazoline series selectively inhibit KRAS G12C-dependent signaling and cancer cell growth at sub-micromolar concentrations.

  16. Predicting DPP-IV inhibitors with machine learning approaches

    Science.gov (United States)

    Cai, Jie; Li, Chanjuan; Liu, Zhihong; Du, Jiewen; Ye, Jiming; Gu, Qiong; Xu, Jun

    2017-04-01

    Dipeptidyl peptidase IV (DPP-IV) is a promising Type 2 diabetes mellitus (T2DM) drug target. DPP-IV inhibitors prolong the action of glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP), improve glucose homeostasis without weight gain, edema, and hypoglycemia. However, the marketed DPP-IV inhibitors have adverse effects such as nasopharyngitis, headache, nausea, hypersensitivity, skin reactions and pancreatitis. Therefore, it is still expected for novel DPP-IV inhibitors with minimal adverse effects. The scaffolds of existing DPP-IV inhibitors are structurally diversified. This makes it difficult to build virtual screening models based upon the known DPP-IV inhibitor libraries using conventional QSAR approaches. In this paper, we report a new strategy to predict DPP-IV inhibitors with machine learning approaches involving naïve Bayesian (NB) and recursive partitioning (RP) methods. We built 247 machine learning models based on 1307 known DPP-IV inhibitors with optimized molecular properties and topological fingerprints as descriptors. The overall predictive accuracies of the optimized models were greater than 80%. An external test set, composed of 65 recently reported compounds, was employed to validate the optimized models. The results demonstrated that both NB and RP models have a good predictive ability based on different combinations of descriptors. Twenty "good" and twenty "bad" structural fragments for DPP-IV inhibitors can also be derived from these models for inspiring the new DPP-IV inhibitor scaffold design.

  17. Small Molecule Inhibitors in Acute Myeloid Leukemia: From the Bench to the Clinic

    Science.gov (United States)

    Al-Hussaini, Muneera; DiPersio, John F.

    2014-01-01

    Many patients with acute myeloid leukemia (AML) will eventually develop refractory or relapsed disease. In the absence of standard therapy for this population, there is currently an urgent unmet need for novel therapeutic agents. Targeted therapy with small molecule inhibitors (SMIs) represents a new therapeutic intervention that has been successful for the treatment of multiple tumors (e.g., gastrointestinal stromal tumors, chronic myelogenous leukemia). Hence, there has been great interest in generating selective small molecule inhibitors targeting critical pathways of proliferation and survival in AML. This review highlights a selective group of intriguing therapeutic agents and their presumed targets in both preclinical models and in early human clinical trials. PMID:25025370

  18. A pilot trial of the mTOR (mammalian target of rapamycin) inhibitor RAD001 in patients with advanced B-CLL.

    Science.gov (United States)

    Decker, Thomas; Sandherr, Michael; Goetze, Katharina; Oelsner, Madlen; Ringshausen, Ingo; Peschel, Christian

    2009-03-01

    Although B-cell chronic lymphocytic leukemia (CLL) is treatable, it remains an incurable disease and most patients inevitably suffer relapse. Many therapeutic options exist for those requiring therapy, including monoclonal antibodies and stem cell transplantation, but remissions tend to last shorter in the course of the disease. Targeting the cell cycle has recently been realized to be an attractive therapeutic approach in solid and hematological malignancies, and the proliferative nature of B-CLL is increasingly accepted. Here, we report data on a phase II pilot trial with the oral mammalian target of rapamycin (mTOR) inhibitor RAD001 5 mg/daily in patients with advanced B-CLL who had progressive disease after at least two lines of treatment. After treatment of seven patients, this trial was stopped because of toxicity concerns, although some degree of activity was observed (one partial remission, three patients with stable disease). Interestingly, cyclin E expression decreased in responding patients. Further strategies of mTOR inhibition by RAD001 in B-CLL should focus on different treatment schedules, adequate anti-infectious prophylaxis, or combinations with cytotoxic drugs.

  19. A focused fragment library targeting the antibiotic resistance enzyme - Oxacillinase-48: Synthesis, structural evaluation and inhibitor design.

    Science.gov (United States)

    Akhter, Sundus; Lund, Bjarte Aarmo; Ismael, Aya; Langer, Manuel; Isaksson, Johan; Christopeit, Tony; Leiros, Hanna-Kirsti S; Bayer, Annette

    2018-02-10

    β-Lactam antibiotics are of utmost importance when treating bacterial infections in the medical community. However, currently their utility is threatened by the emergence and spread of β-lactam resistance. The most prevalent resistance mechanism to β-lactam antibiotics is expression of β-lactamase enzymes. One way to overcome resistance caused by β-lactamases, is the development of β-lactamase inhibitors and today several β-lactamase inhibitors e.g. avibactam, are approved in the clinic. Our focus is the oxacillinase-48 (OXA-48), an enzyme reported to spread rapidly across the world and commonly identified in Escherichia coli and Klebsiella pneumoniae. To guide inhibitor design, we used diversely substituted 3-aryl and 3-heteroaryl benzoic acids to probe the active site of OXA-48 for useful enzyme-inhibitor interactions. In the presented study, a focused fragment library containing 49 3-substituted benzoic acid derivatives were synthesised and biochemically characterized. Based on crystallographic data from 33 fragment-enzyme complexes, the fragments could be classified into R 1 or R 2 binders by their overall binding conformation in relation to the binding of the R 1 and R 2 side groups of imipenem. Moreover, binding interactions attractive for future inhibitor design were found and their usefulness explored by the rational design and evaluation of merged inhibitors from orthogonally binding fragments. The best inhibitors among the resulting 3,5-disubstituted benzoic acids showed inhibitory potential in the low micromolar range (IC 50  = 2.9 μM). For these inhibitors, the complex X-ray structures revealed non-covalent binding to Arg250, Arg214 and Tyr211 in the active site and the interactions observed with the mono-substituted fragments were also identified in the merged structures. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  20. Synthesis and application of polyaminoamide as new paraffin inhibitor from vegetable oil

    OpenAIRE

    Chen, Gang; Tang, Ying; Zhang, Jie

    2011-01-01

    Abstract In this work, a series of novel paraffin inhibitor, polyaminoamide (PAA), was designed and prepared by aminolysis and poly-condensation using soybean oil and canola oil as the raw material. The property of the PAAs as paraffin inhibitor was investigated, the results show several PAA samples are potent in paraffin inhibition, and PPC-2 is the most effective one. Besides, the paraffin crystal morphology analysis was carried out to provide the mechanism of paraffin inhibition.

  1. High-throughput screening to identify inhibitors of lysine demethylases.

    Science.gov (United States)

    Gale, Molly; Yan, Qin

    2015-01-01

    Lysine demethylases (KDMs) are epigenetic regulators whose dysfunction is implicated in the pathology of many human diseases including various types of cancer, inflammation and X-linked intellectual disability. Particular demethylases have been identified as promising therapeutic targets, and tremendous efforts are being devoted toward developing suitable small-molecule inhibitors for clinical and research use. Several High-throughput screening strategies have been developed to screen for small-molecule inhibitors of KDMs, each with advantages and disadvantages in terms of time, cost, effort, reliability and sensitivity. In this Special Report, we review and evaluate the High-throughput screening methods utilized for discovery of novel small-molecule KDM inhibitors.

  2. The Process and Strategy for Developing Selective Histone Deacetylase 3 Inhibitors

    Directory of Open Access Journals (Sweden)

    Fangyuan Cao

    2018-03-01

    Full Text Available Histone deacetylases (HDACs are epigenetic drug targets that have gained major scientific attention. Inhibition of these important regulatory enzymes is used to treat cancer, and has the potential to treat a host of other diseases. However, currently marketed HDAC inhibitors lack selectivity for the various HDAC isoenzymes. Several studies have shown that HDAC3, in particular, plays an important role in inflammation and degenerative neurological diseases, but the development of selective HDAC3 inhibitors has been challenging. This review provides an up-to-date overview of selective HDAC3 inhibitors, and aims to support the development of novel HDAC3 inhibitors in the future.

  3. Hedgehog Signaling Inhibitors as Anti-Cancer Agents in Osteosarcoma

    International Nuclear Information System (INIS)

    Ram Kumar, Ram Mohan; Fuchs, Bruno

    2015-01-01

    Osteosarcoma is a rare type of cancer associated with a poor clinical outcome. Even though the pathologic characteristics of OS are well established, much remains to be understood, particularly at the molecular signaling level. The molecular mechanisms of osteosarcoma progression and metastases have not yet been fully elucidated and several evolutionary signaling pathways have been found to be linked with osteosarcoma pathogenesis, especially the hedgehog signaling (Hh) pathway. The present review will outline the importance and targeting the hedgehog signaling (Hh) pathway in osteosarcoma tumor biology. Available data also suggest that aberrant Hh signaling has pro-migratory effects and leads to the development of osteoblastic osteosarcoma. Activation of Hh signaling has been observed in osteosarcoma cell lines and also in primary human osteosarcoma specimens. Emerging data suggests that interference with Hh signal transduction by inhibitors may reduce osteosarcoma cell proliferation and tumor growth thereby preventing osteosarcomagenesis. From this perspective, we outline the current state of Hh pathway inhibitors in osteosarcoma. In summary, targeting Hh signaling by inhibitors promise to increase the efficacy of osteosarcoma treatment and improve patient outcome

  4. Cytological profile of antibacterial FtsZ inhibitors and synthetic peptide MciZ

    Directory of Open Access Journals (Sweden)

    Lidia Araujo-Bazan

    2016-10-01

    Full Text Available Cell division protein FtsZ is the organizer of the cytokinetic ring in almost all bacteria and a target for the discovery of new antibacterial agents that are needed to counter widespread antibiotic resistance. Bacterial cytological profiling, using quantitative microscopy, is a powerful approach for identifying the mechanism of action of antibacterial molecules affecting different cellular pathways. We have determined the cytological profile on Bacillus subtilis cells of a selection of small molecule inhibitors targeting FtsZ on different binding sites. FtsZ inhibitors lead to long undivided cells, impair the normal assembly of FtsZ into the midcell Z-rings, induce aberrant ring distributions, punctate FtsZ foci, membrane spots and also modify nucleoid length. Quantitative analysis of cell and nucleoid length combined, or the Z-ring distribution, allows categorizing FtsZ inhibitors and to distinguish them from antibiotics with other mechanisms of action, which should be useful for identifying new antibacterial FtsZ inhibitors. Biochemical assays of FtsZ polymerization and GTPase activity combined explain the cellular effects of the FtsZ polymer stabilizing agent PC190723 and its fragments. MciZ is a 40-aminoacid endogenous inhibitor of cell division normally expressed during sporulation in B. subtilis. Using FtsZ cytological profiling we have determined that exogenous synthetic MciZ is an effective inhibitor of B. subtilis cell division, Z-ring formation and localization. This finding supports our cell-based approach to screen for FtsZ inhibitors and opens new possibilities for peptide inhibitors of bacterial cell division.

  5. Synthesis of (benzimidazol-2-yl)aniline derivatives as glycogen phosphorylase inhibitors.

    Science.gov (United States)

    Galal, Shadia A; Khattab, Muhammad; Andreadaki, Fotini; Chrysina, Evangelia D; Praly, Jean-Pierre; Ragab, Fatma A F; El Diwani, Hoda I

    2016-11-01

    A series of (benzimidazol-2-yl)-aniline (1) derivatives has been synthesized and evaluated as glycogen phosphorylase (GP) inhibitors. Kinetics studies revealed that compounds displaying a lateral heterocyclic residue with several heteroatoms (series 3 and 5) exhibited modest inhibitory properties with IC 50 values in the 400-600μM range. Arylsulfonyl derivatives 7 (Ar: phenyl) and 9 (Ar: o-nitrophenyl) of 1 exhibited the highest activity (series 2) among the studied compounds (IC 50 324μM and 357μM, respectively) with stronger effect than the p-tolyl analogue 8. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Novel structural hybrids of pyrazolobenzothiazines with benzimidazoles as cholinesterase inhibitors.

    Science.gov (United States)

    Aslam, Sana; Zaib, Sumera; Ahmad, Matloob; Gardiner, John M; Ahmad, Aqeel; Hameed, Abdul; Furtmann, Norbert; Gütschow, Michael; Bajorath, Jürgen; Iqbal, Jamshed

    2014-05-06

    Two series of novel pyrazolobenzothiazine-based hybrid compounds were efficiently synthesized starting from saccharin sodium salt. Pyrazolo[4,3-c][1,2]benzothiazine scaffolds were N-arylated by using p-fluorobenzaldehyde, followed by the incorporation of a benzimidazole or similar ring systems by treatment with arylenediamines. These phenylene-connected hybrid compounds were investigated as potential inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). Compounds 12d and 12k were the most potent AChE inhibitors with IC50 values of 11 and 13 nM, respectively, while 6j (IC50 = 17 nM) proved to be the most active inhibitor against BuChE with remarkable selectivity for BuChE over AChE. Molecular docking studies were also performed on human AChE and BuChE to suggest possible binding modes in which the inhibitor's extended structure is accommodated along the active site gorge of both enzymes. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  7. Novel dual small-molecule HIV inhibitors: scaffolds and discovery strategies.

    Science.gov (United States)

    Song, Anran; Yu, Haiqing; Wang, Changyuan; Zhu, Xingqi; Liu, Kexin; Ma, Xiaodong

    2015-01-01

    Searching for safe and effective treatments for HIV infection is still a great challenge worldwide in spite of the 27 marketed anti-HIV drugs and the powerful highly active antiretroviral therapy (HAART). As a promising prospect for generation of new HIV therapy drugs, multiple ligands (MDLs) were greatly focused on recently due to their lower toxicity, simplified dosing and patient adherence than single-target drugs. Till now, by disrupting two active sites or steps of HIV replications, a number of HIV dual inhibitors, such as CD4-gssucap120 inhibitors, CXCR4-gp20 inhibitors, RT-CXCR4 inhibitors, RT-protease inhibitors, RT-integrase inhibitors, and RTassociated functions inhibitors have been identified. Generally, these dual inhibitors were discovered mainly through screening approaches and design strategies. Of these compounds, the molecules bearing small skeletons exhibited strong anti-HIV activity and aroused great attention recently. Reviewing the progress of the dual small-molecule HIV inhibitors from the point of view of their scaffolds and discovery strategies will provide valuable information for producing more effective anti-HIV drugs. In this regard, novel dual small-molecule HIV inhibitors were illustrated, and their discovery paradigms as the major contents were also summarized in this manuscript.

  8. CD4-specific designed ankyrin repeat proteins are novel potent HIV entry inhibitors with unique characteristics.

    Directory of Open Access Journals (Sweden)

    Andreas Schweizer

    2008-07-01

    Full Text Available Here, we describe the generation of a novel type of HIV entry inhibitor using the recently developed Designed Ankyrin Repeat Protein (DARPin technology. DARPin proteins specific for human CD4 were selected from a DARPin DNA library using ribosome display. Selected pool members interacted specifically with CD4 and competed with gp120 for binding to CD4. DARPin proteins derived in the initial selection series inhibited HIV in a dose-dependent manner, but showed a relatively high variability in their capacity to block replication of patient isolates on primary CD4 T cells. In consequence, a second series of CD4-specific DARPins with improved affinity for CD4 was generated. These 2nd series DARPins potently inhibit infection of genetically divergent (subtype B and C HIV isolates in the low nanomolar range, independent of coreceptor usage. Importantly, the actions of the CD4 binding DARPins were highly specific: no effect on cell viability or activation, CD4 memory cell function, or interference with CD4-independent virus entry was observed. These novel CD4 targeting molecules described here combine the unique characteristics of DARPins-high physical stability, specificity and low production costs-with the capacity to potently block HIV entry, rendering them promising candidates for microbicide development.

  9. New Estimation of the Dosage of Scale Inhibitor in the Cooling Water System

    Directory of Open Access Journals (Sweden)

    Jiang Jiaomei

    2011-01-01

    Full Text Available In the cooling water system, excessive use of organic phosphate scale inhibitors is harmful to environment. Reducing the dosage of the organic phosphate scale inhibitor is important. A self-made jacketed crystallizer was used in this experiment. The critical pH values have been determined in cooling water systems with series of Ca2+ concentrations by adding different concentration of the scale inhibitor ATMP (Amino Trimethylene Phosphonic Acid according to the calcium carbonate Metastable zone theory. A model equation at 45 °C and pH=9 was proposed to estimate the lowest dose of the scale inhibitor ATMP. The measured pH value was approximate to the expected pH value in two cooling water systems through verification test.

  10. Second-generation inhibitors of Bruton tyrosine kinase

    Directory of Open Access Journals (Sweden)

    Jingjing Wu

    2016-09-01

    Full Text Available Abstract Bruton tyrosine kinase (BTK is a critical effector molecule for B cell development and plays a major role in lymphoma genesis. Ibrutinib is the first-generation BTK inhibitor. Ibrutinib has off-target effects on EGFR, ITK, and Tec family kinases, which explains the untoward effects of ibrutinib. Resistance to ibrutinib was also reported. The C481S mutation in the BTK kinase domain was reported to be a major mechanism of resistance to ibrutinib. This review summarizes the clinical development of novel BTK inhibitors, ACP-196 (acalabrutinib, ONO/GS-4059, and BGB-3111.

  11. Selectivity Profiling and Biological Activity of Novel β-Carbolines as Potent and Selective DYRK1 Kinase Inhibitors.

    Directory of Open Access Journals (Sweden)

    Katharina Rüben

    Full Text Available DYRK1A is a pleiotropic protein kinase with diverse functions in cellular regulation, including cell cycle control, neuronal differentiation, and synaptic transmission. Enhanced activity and overexpression of DYRK1A have been linked to altered brain development and function in Down syndrome and neurodegenerative diseases such as Alzheimer's disease. The β-carboline alkaloid harmine is a high affinity inhibitor of DYRK1A but suffers from the drawback of inhibiting monoamine oxidase A (MAO-A with even higher potency. Here we characterized a series of novel harmine analogs with minimal or absent MAO-A inhibitory activity. We identified several inhibitors with submicromolar potencies for DYRK1A and selectivity for DYRK1A and DYRK1B over the related kinases DYRK2 and HIPK2. An optimized inhibitor, AnnH75, inhibited CLK1, CLK4, and haspin/GSG2 as the only off-targets in a panel of 300 protein kinases. In cellular assays, AnnH75 dose-dependently reduced the phosphorylation of three known DYRK1A substrates (SF3B1, SEPT4, and tau without negative effects on cell viability. AnnH75 inhibited the cotranslational tyrosine autophosphorylation of DYRK1A and threonine phosphorylation of an exogenous substrate protein with similar potency. In conclusion, we have characterized an optimized β-carboline inhibitor as a highly selective chemical probe that complies with desirable properties of drug-like molecules and is suitable to interrogate the function of DYRK1A in biological studies.

  12. Targeting the Thioredoxin System for Cancer Therapy.

    Science.gov (United States)

    Zhang, Junmin; Li, Xinming; Han, Xiao; Liu, Ruijuan; Fang, Jianguo

    2017-09-01

    Thioredoxin (Trx) and thioredoxin reductase (TrxR) are essential components of the Trx system which plays pivotal roles in regulating multiple cellular redox signaling pathways. In recent years TrxR/Trx have been increasingly recognized as an important modulator of tumor development, and hence targeting TrxR/Trx is a promising strategy for cancer treatment. In this review we first discuss the structural details of TrxR, the functions of the Trx system, and the rational of targeting TrxR/Trx for cancer treatment. We also highlight small-molecule TrxR/Trx inhibitors that have potential anticancer activity and review their mechanisms of action. Finally, we examine the challenges of developing TrxR/Trx inhibitors as anticancer agents and perspectives for selectively targeting TrxR/Trx. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Discovery of MK-8718, an HIV Protease Inhibitor Containing a Novel Morpholine Aspartate Binding Group

    Energy Technology Data Exchange (ETDEWEB)

    Bungard, Christopher J.; Williams, Peter D.; Ballard, Jeanine E.; Bennett, David J.; Beaulieu, Christian; Bahnck-Teets, Carolyn; Carroll, Steve S.; Chang, Ronald K.; Dubost, David C.; Fay, John F.; Diamond, Tracy L.; Greshock, Thomas J.; Hao, Li; Holloway, M. Katharine; Felock, Peter J.; Gesell, Jennifer J.; Su, Hua-Poo; Manikowski, Jesse J.; McKay, Daniel J.; Miller, Mike; Min, Xu; Molinaro, Carmela; Moradei, Oscar M.; Nantermet, Philippe G.; Nadeau, Christian; Sanchez, Rosa I.; Satyanarayana, Tummanapalli; Shipe, William D.; Singh, Sanjay K.; Truong, Vouy Linh; Vijayasaradhi, Sivalenka; Wiscount, Catherine M.; Vacca, Joseph P.; Crane, Sheldon N.; McCauley, John A. (Merck); (Albany MR)

    2016-07-14

    A novel HIV protease inhibitor was designed using a morpholine core as the aspartate binding group. Analysis of the crystal structure of the initial lead bound to HIV protease enabled optimization of enzyme potency and antiviral activity. This afforded a series of potent orally bioavailable inhibitors of which MK-8718 was identified as a compound with a favorable overall profile.

  14. Discovery of novel dengue virus NS5 methyltransferase non-nucleoside inhibitors by fragment-based drug design.

    Science.gov (United States)

    Benmansour, Fatiha; Trist, Iuni; Coutard, Bruno; Decroly, Etienne; Querat, Gilles; Brancale, Andrea; Barral, Karine

    2017-01-05

    With the aim to help drug discovery against dengue virus (DENV), a fragment-based drug design approach was applied to identify ligands targeting a main component of DENV replication complex: the NS5 AdoMet-dependent mRNA methyltransferase (MTase) domain, playing an essential role in the RNA capping process. Herein, we describe the identification of new inhibitors developed using fragment-based, structure-guided linking and optimization techniques. Thermal-shift assay followed by a fragment-based X-ray crystallographic screening lead to the identification of three fragment hits binding DENV MTase. We considered linking two of them, which bind to proximal sites of the AdoMet binding pocket, in order to improve their potency. X-ray crystallographic structures and computational docking were used to guide the fragment linking, ultimately leading to novel series of non-nucleoside inhibitors of flavivirus MTase, respectively N-phenyl-[(phenylcarbamoyl)amino]benzene-1-sulfonamide and phenyl [(phenylcarbamoyl)amino]benzene-1-sulfonate derivatives, that show a 10-100-fold stronger inhibition of 2'-O-MTase activity compared to the initial fragments. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  15. Advances in the therapeutic use of mammalian target of rapamycin (mTOR) inhibitors in dermatology.

    Science.gov (United States)

    Fogel, Alexander L; Hill, Sharleen; Teng, Joyce M C

    2015-05-01

    Significant developments in the use of mammalian target of rapamycin (mTOR) inhibitors (mTORIs) as immunosuppressant and antiproliferative agents have been made. Recent advances in the understanding of the mTOR signaling pathway and its downstream effects on tumorigenesis and vascular proliferation have broadened the clinical applications of mTORIs in many challenging disorders such as tuberous sclerosis complex, pachyonychia congenita, complex vascular anomalies, and inflammatory dermatoses. Systemic mTORI therapy has shown benefits in these areas, but is associated with significant side effects that sometimes necessitate drug holidays. To mitigate the side effects of systemic mTORIs for dermatologic applications, preliminary work to assess the potential of percutaneous therapy has been performed, and the evidence suggests that percutaneous delivery of mTORIs may allow for effective long-term therapy while avoiding systemic toxicities. Additional large placebo-controlled, double-blinded, randomized studies are needed to assess the efficacy, safety, duration, and tolerability of topical treatments. The objective of this review is to provide updated information on the novel use of mTORIs in the management of many cutaneous disorders. Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  16. Th17 Inhibitors in Active Psoriatic Arthritis

    DEFF Research Database (Denmark)

    Naik, Girish S; Ming, Wai K; Magodoro, Itai M

    2018-01-01

    BACKGROUND: Several biologics targeting the Th17 pathway have been developed for the treatment of psoriatic arthritis (PsA), a disabling disease with moderate response and an increased incidence of serious infections to first-line biologics (TNF-α antagonists). Th17 inhibitors could replace TNF-α...

  17. Targeted Metabolomics Approach To Detect the Misuse of Steroidal Aromatase Inhibitors in Equine Sports by Biomarker Profiling.

    Science.gov (United States)

    Chan, George Ho Man; Ho, Emmie Ngai Man; Leung, David Kwan Kon; Wong, Kin Sing; Wan, Terence See Ming

    2016-01-05

    The use of anabolic androgenic steroids (AAS) is prohibited in both human and equine sports. The conventional approach in doping control testing for AAS (as well as other prohibited substances) is accomplished by the direct detection of target AAS or their characteristic metabolites in biological samples using hyphenated techniques such as gas chromatography or liquid chromatography coupled with mass spectrometry. Such an approach, however, falls short when dealing with unknown designer steroids where reference materials and their pharmacokinetics are not available. In addition, AASs with fast elimination times render the direct detection approach ineffective as the detection window is short. A targeted metabolomics approach is a plausible alternative to the conventional direct detection approach for controlling the misuse of AAS in sports. Because the administration of AAS of the same class may trigger similar physiological responses or effects in the body, it may be possible to detect such administrations by monitoring changes in the endogenous steroidal expression profile. This study attempts to evaluate the viability of using the targeted metabolomics approach to detect the administration of steroidal aromatase inhibitors, namely androst-4-ene-3,6,17-trione (6-OXO) and androsta-1,4,6-triene-3,17-dione (ATD), in horses. Total (free and conjugated) urinary concentrations of 31 endogenous steroids were determined by gas chromatography-tandem mass spectrometry for a group of 2 resting and 2 in-training thoroughbred geldings treated with either 6-OXO or ATD. Similar data were also obtained from a control (untreated) group of in-training thoroughbred geldings (n = 28). Statistical processing and chemometric procedures using principle component analysis and orthogonal projection to latent structures-discriminant analysis (OPLS-DA) have highlighted 7 potential biomarkers that could be used to differentiate urine samples obtained from the control and the treated groups

  18. Divergent modes of enzyme inhibition in a homologous structure-activity series.

    Science.gov (United States)

    Ferreira, Rafaela S; Bryant, Clifford; Ang, Kenny K H; McKerrow, James H; Shoichet, Brian K; Renslo, Adam R

    2009-08-27

    A docking screen identified reversible, noncovalent inhibitors (e.g., 1) of the parasite cysteine protease cruzain. Chemical optimization of 1 led to a series of oxadiazoles possessing interpretable SAR and potencies as much as 500-fold greater than 1. Detailed investigation of the SAR series subsequently revealed that many members of the oxadiazole class (and surprisingly also 1) act via divergent modes of inhibition (competitive or via colloidal aggregation) depending on the assay conditions employed.

  19. Selective small-molecule inhibitors as chemical tools to define the roles of matrix metalloproteinases in disease.

    Science.gov (United States)

    Meisel, Jayda E; Chang, Mayland

    2017-11-01

    The focus of this article is to highlight novel inhibitors and current examples where the use of selective small-molecule inhibitors has been critical in defining the roles of matrix metalloproteinases (MMPs) in disease. Selective small-molecule inhibitors are surgical chemical tools that can inhibit the targeted enzyme; they are the method of choice to ascertain the roles of MMPs and complement studies with knockout animals. This strategy can identify targets for therapeutic development as exemplified by the use of selective small-molecule MMP inhibitors in diabetic wound healing, spinal cord injury, stroke, traumatic brain injury, cancer metastasis, and viral infection. This article is part of a Special Issue entitled: Matrix Metalloproteinases edited by Rafael Fridman. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Pre-series and testing route for the serial fabrication of W7-X target elements

    International Nuclear Information System (INIS)

    Boscary, J.; Greuner, H.; Friedrich, T.; Traxler, H.; Mendelevitch, B.; Boeswirth, B.; Schlosser, J.; Smirnow, M.; Stadler, R.

    2009-01-01

    The fabrication of the actively cooled high-heat flux divertor of the WENDELSTEIN 7-X stellarator (W7-X) requires the delivery of 890 target elements, which are designed to withstand a stationary heat flux of 10 MW/m 2 . The organization of the manufacturing and testing route for the serial fabrication is the result of the pre-series activities. Flat CFC Sepcarb NB31 tiles are bonded to CuCrZr copper alloy cooling structure in consecutive steps. A copper layer is active metal cast to CFC tiles, and then an OF-copper layer is added by hot isostatic pressing to produce bi-layer tiles. These tiles are bonded by electron beam welding onto the cooling structure, which was manufactured independently. The introduction of the bi-layer technology proved to be a significant improvement of the bond reliability under thermal cycling loading. This result is also the consequence of the improved bond inspections throughout the manufacturing route performed in the ARGUS pulsed thermography facility of PLANSEE. The repairing process by electron beam welding of the bonding was also qualified. The extended pre-series activities related to the qualification of fabrication processes with the relevant non-destructive examinations aim to minimize the risks for the serial manufacturing and to guarantee the steady-state operation of the W7-X divertor.

  1. Histone deacetylase inhibitors (HDACIs: multitargeted anticancer agents

    Directory of Open Access Journals (Sweden)

    Ververis K

    2013-02-01

    Full Text Available Katherine Ververis,1 Alison Hiong,1 Tom C Karagiannis,1,* Paul V Licciardi2,*1Epigenomic Medicine, Alfred Medical Research and Education Precinct, 2Allergy and Immune Disorders, Murdoch Childrens Research Institute, Melbourne, VIC, Australia*These authors contributed equally to this workAbstract: Histone deacetylase (HDAC inhibitors are an emerging class of therapeutics with potential as anticancer drugs. The rationale for developing HDAC inhibitors (and other chromatin-modifying agents as anticancer therapies arose from the understanding that in addition to genetic mutations, epigenetic changes such as dysregulation of HDAC enzymes can alter phenotype and gene expression, disturb homeostasis, and contribute to neoplastic growth. The family of HDAC inhibitors is large and diverse. It includes a range of naturally occurring and synthetic compounds that differ in terms of structure, function, and specificity. HDAC inhibitors have multiple cell type-specific effects in vitro and in vivo, such as growth arrest, cell differentiation, and apoptosis in malignant cells. HDAC inhibitors have the potential to be used as monotherapies or in combination with other anticancer therapies. Currently, there are two HDAC inhibitors that have received approval from the US FDA for the treatment of cutaneous T-cell lymphoma: vorinostat (suberoylanilide hydroxamic acid, Zolinza and depsipeptide (romidepsin, Istodax. More recently, depsipeptide has also gained FDA approval for the treatment of peripheral T-cell lymphoma. Many more clinical trials assessing the effects of various HDAC inhibitors on hematological and solid malignancies are currently being conducted. Despite the proven anticancer effects of particular HDAC inhibitors against certain cancers, many aspects of HDAC enzymes and HDAC inhibitors are still not fully understood. Increasing our understanding of the effects of HDAC inhibitors, their targets and mechanisms of action will be critical for the

  2. GSK-3 inhibitors induce chromosome instability

    Directory of Open Access Journals (Sweden)

    Staples Oliver D

    2007-08-01

    Full Text Available Abstract Background Several mechanisms operate during mitosis to ensure accurate chromosome segregation. However, during tumour evolution these mechanisms go awry resulting in chromosome instability. While several lines of evidence suggest that mutations in adenomatous polyposis coli (APC may promote chromosome instability, at least in colon cancer, the underlying mechanisms remain unclear. Here, we turn our attention to GSK-3 – a protein kinase, which in concert with APC, targets β-catenin for proteolysis – and ask whether GSK-3 is required for accurate chromosome segregation. Results To probe the role of GSK-3 in mitosis, we inhibited GSK-3 kinase activity in cells using a panel of small molecule inhibitors, including SB-415286, AR-A014418, 1-Azakenpaullone and CHIR99021. Analysis of synchronised HeLa cells shows that GSK-3 inhibitors do not prevent G1/S progression or cell division. They do, however, significantly delay mitotic exit, largely because inhibitor-treated cells have difficulty aligning all their chromosomes. Although bipolar spindles form and the majority of chromosomes biorient, one or more chromosomes often remain mono-oriented near the spindle poles. Despite a prolonged mitotic delay, anaphase frequently initiates without the last chromosome aligning, resulting in chromosome non-disjunction. To rule out the possibility of "off-target" effects, we also used RNA interference to selectively repress GSK-3β. Cells deficient for GSK-3β exhibit a similar chromosome alignment defect, with chromosomes clustered near the spindle poles. GSK-3β repression also results in cells accumulating micronuclei, a hallmark of chromosome missegregation. Conclusion Thus, not only do our observations indicate a role for GSK-3 in accurate chromosome segregation, but they also raise the possibility that, if used as therapeutic agents, GSK-3 inhibitors may induce unwanted side effects by inducing chromosome instability.

  3. PI3Kδ inhibitor idelalisib in combination with BTK inhibitor ONO/GS-4059 in diffuse large B cell lymphoma with acquired resistance to PI3Kδ and BTK inhibitors.

    Directory of Open Access Journals (Sweden)

    Anella Yahiaoui

    Full Text Available Activated B-cell-like diffuse large B-cell lymphoma relies on B-cell receptor signaling to drive proliferation and survival. Downstream of the B-cell receptor, the key signaling kinases Bruton's tyrosine kinase and phosphoinositide 3-kinase δ offer opportunities for therapeutic intervention by agents such as ibrutinib, ONO/GS-4059, and idelalisib. Combination therapy with such targeted agents could provide enhanced efficacy due to complimentary mechanisms of action. In this study, we describe both the additive interaction of and resistance mechanisms to idelalisib and ONO/GS-4059 in a model of activated B-cell-like diffuse large B-cell lymphoma. Significant tumor regression was observed with a combination of PI3Kδ and Bruton's tyrosine kinase inhibitors in the mouse TMD8 xenograft. Acquired resistance to idelalisib in the TMD8 cell line occurred by loss of phosphatase and tensin homolog and phosphoinositide 3-kinase pathway upregulation, but not by mutation of PIK3CD. Sensitivity to idelalisib could be restored by combining idelalisib and ONO/GS-4059. Further evaluation of targeted inhibitors revealed that the combination of idelalisib and the phosphoinositide-dependent kinase-1 inhibitor GSK2334470 or the AKT inhibitor MK-2206 could partially overcome resistance. Characterization of acquired Bruton's tyrosine kinase inhibitor resistance revealed a novel tumor necrosis factor alpha induced protein 3 mutation (TNFAIP3 Q143*, which led to a loss of A20 protein, and increased p-IκBα. The combination of idelalisib and ONO/GS-4059 partially restored sensitivity in this resistant line. Additionally, a mutation in Bruton's tyrosine kinase at C481F was identified as a mechanism of resistance. The combination activity observed with idelalisib and ONO/GS-4059, taken together with the ability to overcome resistance, could lead to a new therapeutic option in activated B-cell-like diffuse large B-cell lymphoma. A clinical trial is currently underway to

  4. Inhibitors of polyamine metabolism: review article.

    Science.gov (United States)

    Wallace, H M; Fraser, A V

    2004-07-01

    The identification of increased polyamine concentrations in a variety of diseases from cancer and psoriasis to parasitic infections has led to the hypothesis that manipulation of polyamine metabolism is a realistic target for therapeutic or preventative intervention in the treatment of certain diseases. The early development of polyamine biosynthetic single enzyme inhibitors such as alpha-difluoromethylornithine (DFMO) and methylglyoxal bis(guanylhydrazone) showed some interesting early promise as anticancer drugs, but ultimately failed in vivo. Despite this, DFMO is currently in use as an effective anti-parasitic agent and has recently also been shown to have further potential as a chemopreventative agent in colorectal cancer. The initial promise in vitro led to the development and testing of other potential inhibitors of the pathway namely the polyamine analogues. The analogues have met with greater success than the single enzyme inhibitors possibly due to their multiple targets. These include down regulation of polyamine biosynthesis through inhibition of ornithine decarboxylase and S-adenosylmethionine decarboxylase and decreased polyamine uptake. This coupled with increased activity of the catabolic enzymes, polyamine oxidase and spermidine/spermine N1-acetyltransferase, and increased polyamine export has made the analogues more effective in depleting polyamine pools. Recently, the identification of a new oxidase (PAO-h1/SMO) in polyamine catabolism and evidence of induction of both PAO and PAO-h1/SMO in response to polyamine analogue treatment, suggests the analogues may become an important part of future chemotherapeutic and/or chemopreventative regimens.

  5. Hypoxia-Inducible Factor-1 as a Therapeutic Target in Endometrial Cancer Management

    Directory of Open Access Journals (Sweden)

    Laura M. S. Seeber

    2010-01-01

    Full Text Available In the Western world, endometrial cancer (EC is the most common malignant tumor of the female genital tract. Solid tumors like EC outgrow their vasculature resulting in hypoxia. Tumor hypoxia is important because it renders an aggressive phenotype and leads to radio- and chemo-therapy resistance. Hypoxia-inducible factor-1 (HIF-1 plays an essential role in the adaptive cellular response to hypoxia and is associated with poor clinical outcome in EC. Therefore, HIF-1 could be an attractive therapeutic target. Selective HIF-1 inhibitors have not been identified. A number of nonselective inhibitors which target signaling pathways upstream or downstream HIF-1 are known to decrease HIF-1 protein levels. In clinical trials for the treatment of advanced and/or recurrent EC are the topoisomerase I inhibitor Topotecan, mTOR-inhibitor Rapamycin, and angiogenesis inhibitor Bevacizumab. Preliminary data shows encouraging results for these agents. Further work is needed to identify selective HIF-1 inhibitors and to translate these into clinical trials.

  6. Insights into the molecular evolution of peptidase inhibitors in arthropods.

    Science.gov (United States)

    Alonso, Joaquin; Martinez, Manuel

    2017-01-01

    Peptidase inhibitors are key proteins involved in the control of peptidases. In arthropods, peptidase inhibitors modulate the activity of peptidases involved in endogenous physiological processes and peptidases of the organisms with which they interact. Exploring available arthropod genomic sequences is a powerful way to obtain the repertoire of peptidase inhibitors in every arthropod species and to understand the evolutionary mechanisms involved in the diversification of this kind of proteins. A genomic comparative analysis of peptidase inhibitors in species belonging to different arthropod taxonomic groups was performed. The results point out: i) species or clade-specific presence is shown for several families of peptidase inhibitors; ii) multidomain peptidase inhibitors are commonly found in many peptidase inhibitor families; iii) several families have a wide range of members in different arthropod species; iv) several peptidase inhibitor families show species-specific (or clade-specific) gene family expansions; v) functional divergence may be assumed for particular clades; vi) passive expansions may be used by natural selection to fix adaptations. In conclusion, conservation and divergence of duplicated genes and the potential recruitment as peptidase inhibitors of proteins from other families are the main mechanisms used by arthropods to fix diversity. This diversity would be associated to the control of target peptidases and, as consequence, to adapt to specific environments.

  7. Decreasing the Rate of Metabolic Ketone Reduction in the Discovery of a Clinical Acetyl-CoA Carboxylase Inhibitor for the Treatment of Diabetes

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, David A. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Kung, Daniel W. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Esler, William P. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Amor, Paul A. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Bagley, Scott W. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Beysen, Carine [KineMed Inc., Emeryville, CA (United States); Carvajal-Gonzalez, Santos [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Doran, Shawn D. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Limberakis, Chris [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Mathiowetz, Alan M. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); McPherson, Kirk [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Price, David A. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Ravussin, Eric [Louisiana State Univ., Baton Rouge, LA (United States); Sonnenberg, Gabriele E. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Southers, James A. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Sweet, Laurel J. [Pfizer Worldwide Research and Development, Cambridge, MA (United States); Turner, Scott M. [KineMed Inc., Emeryville, CA (United States); Vajdos, Felix F. [Pfizer Worldwide Research and Development, Cambridge, MA (United States)

    2014-12-26

    We found that Acetyl-CoA carboxylase (ACC) inhibitors offer significant potential for the treatment of type 2 diabetes mellitus (T2DM), hepatic steatosis, and cancer. However, the identification of tool compounds suitable to test the hypothesis in human trials has been challenging. An advanced series of spirocyclic ketone-containing ACC inhibitors recently reported by Pfizer were metabolized in vivo by ketone reduction, which complicated human pharmacology projections. Here, we disclose that this metabolic reduction can be greatly attenuated through introduction of steric hindrance adjacent to the ketone carbonyl. Incorporation of weakly basic functionality improved solubility and led to the identification of 9 as a clinical candidate for the treatment of T2DM. Phase I clinical studies demonstrated dose-proportional increases in exposure, single-dose inhibition of de novo lipogenesis (DNL), and changes in indirect calorimetry consistent with increased whole-body fatty acid oxidation. This demonstration of target engagement validates the use of compound 9 to evaluate the role of DNL in human disease.

  8. Adventures in Scaffold Morphing: Discovery of Fused Ring Heterocyclic Checkpoint Kinase 1 (CHK1) Inhibitors.

    Science.gov (United States)

    Yang, Bin; Vasbinder, Melissa M; Hird, Alexander W; Su, Qibin; Wang, Haixia; Yu, Yan; Toader, Dorin; Lyne, Paul D; Read, Jon A; Breed, Jason; Ioannidis, Stephanos; Deng, Chun; Grondine, Michael; DeGrace, Nancy; Whitston, David; Brassil, Patrick; Janetka, James W

    2018-02-08

    Checkpoint kinase 1 (CHK1) inhibitors are potential cancer therapeutics that can be utilized for enhancing the efficacy of DNA damaging agents. Multiple small molecule CHK1 inhibitors from different chemical scaffolds have been developed and evaluated in clinical trials in combination with chemotherapeutics and radiation treatment. Scaffold morphing of thiophene carboxamide ureas (TCUs), such as AZD7762 (1) and a related series of triazoloquinolines (TZQs), led to the identification of fused-ring bicyclic CHK1 inhibitors, 7-carboxamide thienopyridines (7-CTPs), and 7-carboxamide indoles. X-ray crystal structures reveal a key intramolecular noncovalent sulfur-oxygen interaction in aligning the hinge-binding carboxamide group to the thienopyridine core in a coplanar fashion. An intramolecular hydrogen bond to an indole NH was also effective in locking the carboxamide in the preferred bound conformation to CHK1. Optimization on the 7-CTP series resulted in the identification of lead compound 44, which displayed respectable drug-like properties and good in vitro and in vivo potency.

  9. JAK inhibitors suppress t(8;21) fusion protein-induced leukemia

    Science.gov (United States)

    Lo, Miao-Chia; Peterson, Luke F.; Yan, Ming; Cong, Xiuli; Hickman, Justin H.; DeKelver, Russel C.; Niewerth, Denise; Zhang, Dong-Er

    2014-01-01

    Oncogenic mutations in components of the JAK/STAT pathway, including those in cytokine receptors and JAKs, lead to increased activity of downstream signaling and are frequently found in leukemia and other hematological disorders. Thus, small-molecule inhibitors of this pathway have been the focus of targeted therapy in these hematological diseases. We previously showed that t(8;21) fusion protein AML1-ETO and its alternatively spliced variant AML1-ETO9a (AE9a) enhance the JAK/STAT pathway via down-regulation of CD45, a negative regulator of this pathway. To investigate the therapeutic potential of targeting JAK/STAT in t(8;21) leukemia, we examined the effects of a JAK2-selective inhibitor TG101209 and a JAK1/2-selective inhibitor INCB18424 on t(8;21) leukemia cells. TG101209 and INCB18424 inhibited proliferation and promoted apoptosis of these cells. Furthermore, TG101209 treatment in AE9a leukemia mice reduced tumor burden and significantly prolonged survival. TG101209 also significantly impaired the leukemia-initiating potential of AE9a leukemia cells in secondary recipient mice. These results demonstrate the potential therapeutic efficacy of JAK inhibitors in treating t(8;21) AML. PMID:23812420

  10. Computational Characterization of Small Molecules Binding to the Human XPF Active Site and Virtual Screening to Identify Potential New DNA Repair Inhibitors Targeting the ERCC1-XPF Endonuclease

    Directory of Open Access Journals (Sweden)

    Francesco Gentile

    2018-04-01

    Full Text Available The DNA excision repair protein ERCC-1-DNA repair endonuclease XPF (ERCC1-XPF is a heterodimeric endonuclease essential for the nucleotide excision repair (NER DNA repair pathway. Although its activity is required to maintain genome integrity in healthy cells, ERCC1-XPF can counteract the effect of DNA-damaging therapies such as platinum-based chemotherapy in cancer cells. Therefore, a promising approach to enhance the effect of these therapies is to combine their use with small molecules, which can inhibit the repair mechanisms in cancer cells. Currently, there are no structures available for the catalytic site of the human ERCC1-XPF, which performs the metal-mediated cleavage of a DNA damaged strand at 5′. We adopted a homology modeling strategy to build a structural model of the human XPF nuclease domain which contained the active site and to extract dominant conformations of the domain using molecular dynamics simulations followed by clustering of the trajectory. We investigated the binding modes of known small molecule inhibitors targeting the active site to build a pharmacophore model. We then performed a virtual screening of the ZINC Is Not Commercial 15 (ZINC15 database to identify new ERCC1-XPF endonuclease inhibitors. Our work provides structural insights regarding the binding mode of small molecules targeting the ERCC1-XPF active site that can be used to rationally optimize such compounds. We also propose a set of new potential DNA repair inhibitors to be considered for combination cancer therapy strategies.

  11. Dual PI3K/mTOR inhibitor BEZ235 as a promising therapeutic strategy against paclitaxel-resistant gastric cancer via targeting PI3K/Akt/mTOR pathway.

    Science.gov (United States)

    Chen, Dongshao; Lin, Xiaoting; Zhang, Cheng; Liu, Zhentao; Chen, Zuhua; Li, Zhongwu; Wang, Jingyuan; Li, Beifang; Hu, Yanting; Dong, Bin; Shen, Lin; Ji, Jiafu; Gao, Jing; Zhang, Xiaotian

    2018-01-26

    Paclitaxel (PTX) is widely used in the front-line chemotherapy for gastric cancer (GC), but resistance limits its use. Due to the lack of proper models, mechanisms underlying PTX resistance in GC were not well studied. Using established PTX-resistant GC cell sublines HGC-27R, we for the first time integrated biological traits and molecular mechanisms of PTX resistance in GC. Data revealed that PTX-resistant GC cells were characterized by microtubular disorders, an EMT phenotype, reduced responses to antimitotic drugs, and resistance to apoptosis (marked by upregulated β-tubulin III, vimentin, attenuated changes in G 2 /M molecules or pro-apoptotic factors in response to antimitotic drugs or apoptotic inducers, respectively). Activation of the phosphoinositide 3-kinase, the serine/threonine kinase Akt and mammalian target of rapamycin (PI3K/Akt/mTOR) and mitogen-activated protein kinase (MAPK) pathways were also observed, which might be the reason for above phenotypic alternations. In vitro data suggested that targeting these pathways were sufficient to elicit antitumor responses in PTX-resistant GC, in which the dual PI3K/mTOR inhibitor BEZ235 displayed higher therapeutic efficiency than the mTOR inhibitor everolimus or the MEK inhibitor AZD6244. Antitumor effects of BEZ235 were also confirmed in mice bearing HGC-27R tumors. Thus, these data suggest that PI3K/Akt/mTOR and MAPK pathway inhibition, especially PI3K/mTOR dual blockade, might be a promising therapeutic strategy against PTX-resistant GC.

  12. Designing Isoform-selective Inhibitors Against Classical HDACs for Effective Anticancer Therapy: Insight and Perspectives from In Silico.

    Science.gov (United States)

    Ganai, Shabir Ahmad

    2018-01-01

    Histone deacetylase inhibitors, the small molecules modulating the biological activity of histone deacetylases are emerging as potent chemotherapeutic agents. Despite their considerable therapeutic benefits in disease models, the lack of isoform specificity culminates in debilitating off target effects, raising serious concerns regarding their applicability. This emphasizes the pressing and unmet medical need of designing isoform selective inhibitors for safe and effective anticancer therapy. Keeping these grim facts in view, the current article sheds light on structural basis of off-targeting. Furthermore, the article discusses extensively the role of in silico strategies such as Molecular Docking, Molecular Dynamics Simulation and Energetically-optimized structure based pharmacophore approach in designing on-target inhibitors against classical HDACs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  13. Synthesis, evaluation, and mechanism of N,N,N-trimethyl-D-glucosamine-(1→4)-chitooligosaccharides as selective inhibitors of glycosyl hydrolase family 20 β-N-acetyl-D-hexosaminidases.

    Science.gov (United States)

    Yang, You; Liu, Tian; Yang, Yongliang; Wu, Qingyue; Yang, Qing; Yu, Biao

    2011-02-11

    GH20 β-N-acetyl-D-hexosaminidases are enzymes involved in many vital processes. Inhibitors that specifically target GH20 enzymes in pests are of agricultural and economic importance. Structural comparison has revealed that the bacterial chitindegrading β-N-acetyl-D-hexosaminidases each have an extra +1 subsite in the active site; this structural difference could be exploited for the development of selective inhibitors. N,N,Ntrimethyl-D-glucosamine (TMG)-chitotriomycin, which contains three GlcNAc residues, is a natural selective inhibitor against bacterial and insect β-N-acetyl-D-hexosaminidases. However, our structural alignment analysis indicated that the two GlcNAc residues at the reducing end might be unnecessary. To prove this hypothesis, we designed and synthesized a series of TMG-chitotriomycin analogues containing one to four GlcNAc units. Inhibitory kinetics and molecular docking showed that TMG-(GlcNAc)(2), is as active as TMG-chitotriomycin [TMG-(GlcNAc)(3)]. The selective inhibition mechanism of TMG-chitotriomycin was also explained. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Discovery of novel selenium derivatives as Pin1 inhibitors by high-throughput screening

    International Nuclear Information System (INIS)

    Subedi, Amit; Shimizu, Takeshi; Ryo, Akihide; Sanada, Emiko; Watanabe, Nobumoto; Osada, Hiroyuki

    2016-01-01

    Peptidyl prolyl cis/trans isomerization by Pin1 regulates various oncogenic signals during cancer progression, and its inhibition through multiple approaches has established Pin1 as a therapeutic target. However, lack of simplified screening systems has limited the discovery of potent Pin1 inhibitors. We utilized phosphorylation-dependent binding of Pin1 to its specific substrate to develop a screening system for Pin1 inhibitors. Using this system, we screened a chemical library, and identified a novel selenium derivative as Pin1 inhibitor. Based on structure-activity guided chemical synthesis, we developed more potent Pin1 inhibitors that inhibited cancer cell proliferation. -- Highlights: •Novel screening for Pin1 inhibitors based on Pin1 binding is developed. •A novel selenium compound is discovered as Pin1 inhibitor. •Activity guided chemical synthesis of selenium derivatives resulted potent Pin1 inhibitors.

  15. Identification of novel malarial cysteine protease inhibitors using structure-based virtual screening of a focused cysteine protease inhibitor library.

    Science.gov (United States)

    Shah, Falgun; Mukherjee, Prasenjit; Gut, Jiri; Legac, Jennifer; Rosenthal, Philip J; Tekwani, Babu L; Avery, Mitchell A

    2011-04-25

    Malaria, in particular that caused by Plasmodium falciparum , is prevalent across the tropics, and its medicinal control is limited by widespread drug resistance. Cysteine proteases of P. falciparum , falcipain-2 (FP-2) and falcipain-3 (FP-3), are major hemoglobinases, validated as potential antimalarial drug targets. Structure-based virtual screening of a focused cysteine protease inhibitor library built with soft rather than hard electrophiles was performed against an X-ray crystal structure of FP-2 using the Glide docking program. An enrichment study was performed to select a suitable scoring function and to retrieve potential candidates against FP-2 from a large chemical database. Biological evaluation of 50 selected compounds identified 21 diverse nonpeptidic inhibitors of FP-2 with a hit rate of 42%. Atomic Fukui indices were used to predict the most electrophilic center and its electrophilicity in the identified hits. Comparison of predicted electrophilicity of electrophiles in identified hits with those in known irreversible inhibitors suggested the soft-nature of electrophiles in the selected target compounds. The present study highlights the importance of focused libraries and enrichment studies in structure-based virtual screening. In addition, few compounds were screened against homologous human cysteine proteases for selectivity analysis. Further evaluation of structure-activity relationships around these nonpeptidic scaffolds could help in the development of selective leads for antimalarial chemotherapy.

  16. Current Advances in Developing Inhibitors of Bacterial Multidrug 
Efflux Pumps

    Science.gov (United States)

    Mahmood, Hannah Y.; Jamshidi, Shirin; Sutton, J. Mark; Rahman, Khondaker M.

    2016-01-01

    Antimicrobial resistance represents a significant challenge to future healthcare provision. An acronym ESKAPEE has been derived from the names of the organisms recognised as the major threats although there are a number of other organisms, notably Neisseria gonorrhoeae, that have become equally challenging to treat in the clinic. These pathogens are characterised by the ability to rapidly develop and/or acquire resistance mechanisms in response to exposure to different antimicrobial agents. A key part of the armoury of these pathogens is a series of efflux pumps, which effectively exclude or reduce the intracellular concentration of a large number of antibiotics, making the pathogens significantly more resistant. These efflux pumps are the topic of considerable interest, both from the perspective of basic understanding of efflux pump function, and its role in drug resistance but also as targets for the development of novel adjunct therapies. The necessity to overcome antimicrobial resistance has encouraged investigations into the characterisation of resistance-modifying efflux pump inhibitors to block the mechanisms of drug extrusion, thereby restoring antibacterial susceptibility and returning existing antibiotics into the clinic. A greater understanding of drug recognition and transport by multidrug efflux pumps is needed to develop clinically useful inhibitors, given the breadth of molecules that can be effluxed by these systems. This review discusses different bacterial EPIs originating from both natural source and chemical synthesis and examines the challenges to designing successful EPIs that can be useful against multidrug resistant bacteria. PMID:26947776

  17. Identification of [4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)-2-pyrimidinyl] amines and ethers as potent and selective cyclooxygenase-2 inhibitors.

    Science.gov (United States)

    Swarbrick, Martin E; Beswick, Paul J; Gleave, Robert J; Green, Richard H; Bingham, Sharon; Bountra, Chas; Carter, Malcolm C; Chambers, Laura J; Chessell, Iain P; Clayton, Nick M; Collins, Sue D; Corfield, John A; Hartley, C David; Kleanthous, Savvas; Lambeth, Paul F; Lucas, Fiona S; Mathews, Neil; Naylor, Alan; Page, Lee W; Payne, Jeremy J; Pegg, Neil A; Price, Helen S; Skidmore, John; Stevens, Alexander J; Stocker, Richard; Stratton, Sharon C; Stuart, Alastair J; Wiseman, Joanne O

    2009-08-01

    A novel series of [4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)-2-pyrimidine-based cyclooxygenase-2 (COX-2) inhibitors, which have a different arrangement of substituents compared to the more common 1,2-diarylheterocycle based molecules, have been discovered. For example, 2-(butyloxy)-4-[4-(methylsulfonyl)phenyl]-6-(trifluoromethyl)pyrimidine (47), a member of the 2-pyrimidinyl ether series, has been shown to be a potent and selective inhibitor with a favourable pharmacokinetic profile, high brain penetration and good efficacy in rat models of hypersensitivity.

  18. Opportunities to Target Specific Contractile Abnormalities with Smooth Muscle Protein Kinase Inhibitors

    Directory of Open Access Journals (Sweden)

    Annegret Ulke-Lemée

    2010-05-01

    Full Text Available Smooth muscle is a major component of most hollow organ systems (e.g., airways, vasculature, bladder and gut/gastrointestine; therefore, the coordinated regulation of contraction is a key property of smooth muscle. When smooth muscle functions normally, it contributes to general health and wellness, but its dysfunction is associated with morbidity and mortality. Rho-associated protein kinase (ROCK is central to calcium-independent, actomyosin-mediated contractile force generation in the vasculature, thereby playing a role in smooth muscle contraction, cell motility and adhesion. Recent evidence supports an important role for ROCK in the increased vasoconstriction and remodeling observed in various models of hypertension. This review will provide a commentary on the development of specific ROCK inhibitors and their clinical application. Fasudil will be discussed as an example of bench-to-bedside development of a clinical therapeutic that is used to treat conditions of vascular hypercontractility. Due to the wide spectrum of biological processes regulated by ROCK, many additional clinical indications might also benefit from ROCK inhibition. Apart from the importance of ROCK in smooth muscle contraction, a variety of other protein kinases are known to play similar roles in regulating contractile force. The zipper-interacting protein kinase (ZIPK and integrin-linked kinase (ILK are two well-described regulators of contraction. The relative contribution of each kinase to contraction depends on the muscle bed as well as hormonal and neuronal stimulation. Unfortunately, specific inhibitors for ZIPK and ILK are still in the development phase, but the success of fasudil suggests that inhibitors for these other kinases may also have valuable clinical applications. Notably, the directed inhibition of ZIPK with a pseudosubstrate molecule shows unexpected effects on the contractility of gastrointestinal smooth muscle.

  19. An integrated in silico approach to design specific inhibitors targeting human poly(a-specific ribonuclease.

    Directory of Open Access Journals (Sweden)

    Dimitrios Vlachakis

    Full Text Available Poly(A-specific ribonuclease (PARN is an exoribonuclease/deadenylase that degrades 3'-end poly(A tails in almost all eukaryotic organisms. Much of the biochemical and structural information on PARN comes from the human enzyme. However, the existence of PARN all along the eukaryotic evolutionary ladder requires further and thorough investigation. Although the complete structure of the full-length human PARN, as well as several aspects of the catalytic mechanism still remain elusive, many previous studies indicate that PARN can be used as potent and promising anti-cancer target. In the present study, we attempt to complement the existing structural information on PARN with in-depth bioinformatics analyses, in order to get a hologram of the molecular evolution of PARNs active site. In an effort to draw an outline, which allows specific drug design targeting PARN, an unequivocally specific platform was designed for the development of selective modulators focusing on the unique structural and catalytic features of the enzyme. Extensive phylogenetic analysis based on all the publicly available genomes indicated a broad distribution for PARN across eukaryotic species and revealed structurally important amino acids which could be assigned as potentially strong contributors to the regulation of the catalytic mechanism of PARN. Based on the above, we propose a comprehensive in silico model for the PARN's catalytic mechanism and moreover, we developed a 3D pharmacophore model, which was subsequently used for the introduction of DNP-poly(A amphipathic substrate analog as a potential inhibitor of PARN. Indeed, biochemical analysis revealed that DNP-poly(A inhibits PARN competitively. Our approach provides an efficient integrated platform for the rational design of pharmacophore models as well as novel modulators of PARN with therapeutic potential.

  20. A comprehensive review of everolimus clinical reports: a new mammalian target of rapamycin inhibitor.

    Science.gov (United States)

    Gurk-Turner, Cheryle; Manitpisitkul, Wana; Cooper, Matthew

    2012-10-15

    As new immunosuppressive agents are introduced to the market, clinicians are faced with the daunting task of sifting through the published literature to decide the value that the agent will add to their own practice. We often must extrapolate information provided through study in other solid-organ transplantation populations than our specific area of interest as we interpret the results and outcomes. With these challenges in mind, this compilation of published work for the newest mammalian target of rapamycin inhibitor everolimus (Certican; Novartis Pharmaceuticals, Hanover, NJ) (Zortress; Novartis Pharmaceuticals, Basel, Switzerland) is intended to provide a concise but thorough presentation of available literature so that the reader who may be unfamiliar with the agent can make their own judgment. Both Ovid and PubMed search engines were queried with a particular focus on high-impact articles noted in the Web of Science or Citation Index. Work described solely in abstract or case report form was excluded, as well as meta-analyses or those that were editorial or commentary in nature. Included were publications presented using the English language that described adult human subjects who received a heart, lung, kidney, or liver allograft. The goal of this strategy was to allow for the inclusion of pertinent literature in an unbiased fashion. Tables are provided that outline trial specific information, leaving a discussion of major outcomes to the text of the review.

  1. Tubulin Inhibitor-Based Antibody-Drug Conjugates for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Hao Chen

    2017-08-01

    Full Text Available Antibody-drug conjugates (ADCs are a class of highly potent biopharmaceutical drugs generated by conjugating cytotoxic drugs with specific monoclonal antibodies through appropriate linkers. Specific antibodies used to guide potent warheads to tumor tissues can effectively reduce undesired side effects of the cytotoxic drugs. An in-depth understanding of antibodies, linkers, conjugation strategies, cytotoxic drugs, and their molecular targets has led to the successful development of several approved ADCs. These ADCs are powerful therapeutics for cancer treatment, enabling wider therapeutic windows, improved pharmacokinetic/pharmacodynamic properties, and enhanced efficacy. Since tubulin inhibitors are one of the most successful cytotoxic drugs in the ADC armamentarium, this review focuses on the progress in tubulin inhibitor-based ADCs, as well as lessons learned from the unsuccessful ADCs containing tubulin inhibitors. This review should be helpful to facilitate future development of new generations of tubulin inhibitor-based ADCs for cancer therapy.

  2. A thermostable serralysin inhibitor from marine bacterium Flavobacterium sp. YS-80-122

    Science.gov (United States)

    Liang, Pengjuan; Li, Shangyong; Wang, Kun; Wang, Fang; Xing, Mengxin; Hao, Jianhua; Sun, Mi

    2018-03-01

    Serralysin inhibitors have been proposed as potent drugs against many diseases and may help to prevent further development of antibiotic-resistant pathogenic bacteria. In this study, a novel serralysin inhibitor gene, lupI, was cloned from the marine bacterium Flavobacterium sp. YS-80-122 and expressed in Escherichia coli. The deduced serralysin inhibitor, LupI, shows <40% amino acid identity to other reported serralysin inhibitors. Multiple sequence alignment and phylogenetic analysis of LupI with other serralysin inhibitors indicated that LupI was a novel type of serralysin inhibitor. The inhibitory constant for LupI towards its target metalloprotease was 0.64 μmol/L. LupI was thermostable at high temperature, in which 35.6%-90.7% of its inhibitory activity was recovered after treatment at 100°C for 1-60 min followed by incubation at 0°C. This novel inhibitor may represent a candidate drug for the treatment of serralysin-related infections.

  3. Checkpoint inhibitors in cancer immunotherapy: Cross reactivity of a CTLA-4 antibody and IDO-inhibitor L-1MT in pigs

    DEFF Research Database (Denmark)

    Al-Shatrawi, Zina Adil; Frøsig, Thomas Mørch; Jungersen, Gregers

    a non-specific activation of porcine T cells. This will be further investigated to provide the basis for in vivo studies investigating checkpoint inhibitor blockade in combination with other cancer immunotherapies. Eventually our goal is to establish pigs as an alternative large animal model......Blockade of checkpoint inhibitors has recently shown very convincing results in the treatment of cancer. One key target is CTLA-4, which has been demonstrated to be a potent negative regulator of lymphocyte activation. The treatment with the FDA-approved fully human CTLA-4 monoclonal antibody...... Ipilimumab increases anticancer T-cell reactivity and overall survival of metastatic cancer patients. Indole-amine 2,3-dioxygenase (IDO) is another checkpoint inhibitor which suppresses T-cell immunity by the depletion of tryptophan in the T-cell microenvironment, and also inhibition of IDO by L-1...

  4. Substrate and inhibitor specificity of kynurenine monooxygenase from Cytophaga hutchinsonii.

    Science.gov (United States)

    Phillips, Robert S; Anderson, Andrew D; Gentry, Harvey G; Güner, Osman F; Bowen, J Phillip

    2017-04-15

    Kynurenine monooxygenase (KMO) is a potential drug target for treatment of neurodegenerative disorders such as Huntington's and Alzheimer's diseases. We have evaluated substituted kynurenines as substrates or inhibitors of KMO from Cytophaga hutchinsonii. Kynurenines substituted with a halogen at the 5-position are excellent substrates, with values of k cat and k cat /K m comparable to or higher than kynurenine. However, kynurenines substituted in the 3-position are competitive inhibitors, with K I values lower than the K m for kynurenine. Bromination also enhances inhibition, and 3,5-dibromokynurenine is a potent competitive inhibitor with a K I value of 1.5μM. A pharmacophore model of KMO was developed, and predicted that 3,4-dichlorohippuric acid would be an inhibitor. The K I for this compound was found to be 34μM, thus validating the pharmacophore model. We are using these results and our model to design more potent inhibitors of KMO. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. IGF-IR targeted therapy: Past, present and future

    NARCIS (Netherlands)

    J.A.M.J.L. Janssen (Joseph); A.J. Varewijck (Aimee)

    2014-01-01

    textabstractThe IGF-I receptor (IGF-IR) has been studied as an anti-cancer target. However, monotherapy trials with IGF-IR targeted antibodies or with IGF-IR specific tyrosine kinase inhibitors have, overall, been very disappointing in the clinical setting. This review discusses potential reasons

  6. The growing pipeline of natural aminoacyl-tRNA synthetase inhibitors for malaria treatment.

    Science.gov (United States)

    Saint-Léger, Adélaïde; Sinadinos, Christopher; Ribas de Pouplana, Lluís

    2016-04-02

    Malaria remains a major global health problem. Parasite resistance to existing drugs makes development of new antimalarials an urgency. The protein synthesis machinery is an excellent target for the development of new anti-infectives, and aminoacyl-tRNA synthetases (aaRS) have been validated as antimalarial drug targets. However, avoiding the emergence of drug resistance and improving selectivity to target aaRS in apicomplexan parasites, such as Plasmodium falciparum, remain crucial challenges. Here we discuss such issues using examples of known inhibitors of P. falciparum aaRS, namely halofuginone, cladosporin and borrelidin (inhibitors of ProRS, LysRS and ThrRS, respectively). Encouraging recent results provide useful guidelines to facilitate the development of novel drug candidates which are more potent and selective against these essential enzymes.

  7. The design strategy of selective PTP1B inhibitors over TCPTP.

    Science.gov (United States)

    Li, XiangQian; Wang, LiJun; Shi, DaYong

    2016-08-15

    Protein tyrosine phosphatase 1B (PTP1B) has already been well studied as a highly validated therapeutic target for diabetes and obesity. However, the lack of selectivity limited further studies and clinical applications of PTP1B inhibitors, especially over T-cell protein tyrosine phosphatase (TCPTP). In this review, we enumerate the published specific inhibitors of PTP1B, discuss the structure-activity relationships by analysis of their X-ray structures or docking results, and summarize the characteristic of selectivity related residues and groups. Furthermore, the design strategy of selective PTP1B inhibitors over TCPTP is also proposed. We hope our work could provide an effective way to gain specific PTP1B inhibitors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Biochemical Importance of Glycosylation of Plasminogen Activator Inhibitor-1

    DEFF Research Database (Denmark)

    Gils, Ann; Pedersen, Katrine Egelund; Skottrup, Peter

    2003-01-01

    The serpin plasminogen activator inhibitor-1 (PAI-1) is a potential target for anti-thrombotic and anti-cancer therapy. PAI-1 has 3 potential sites for N-linked glycosylation. We demonstrate here that PAI-1 expressed recombinantly or naturally by human cell lines display a heterogeneous glycosyla......The serpin plasminogen activator inhibitor-1 (PAI-1) is a potential target for anti-thrombotic and anti-cancer therapy. PAI-1 has 3 potential sites for N-linked glycosylation. We demonstrate here that PAI-1 expressed recombinantly or naturally by human cell lines display a heterogeneous...... with the glycosylation sites could be excluded as explanation for the differential reactivity. The latency transition of non-glycosylated, but not of glycosylated PAI-1, was strongly accelerated by a non-ionic detergent. The different biochemical properties of glycosylated and non-glycosylated PAI-1 depended...

  9. Targeting Epithelial-Mesenchymal Transition for Identification of Inhibitors for Pancreatic Cancer Cell Invasion and Tumor Spheres Formation.

    Directory of Open Access Journals (Sweden)

    Kishore Polireddy

    Full Text Available Pancreatic cancer has an enrichment of stem-like cancer cells (CSCs that contribute to chemoresistant tumors prone to metastasis and recurrence. Drug screening assays based on cytotoxicity cannot identify specific CSC inhibitors, because CSCs comprise only a small portion of cancer cell population, and it is difficult to propagate stable CSC populations in vitro for high-throughput screening (HTS assays. Based on the important role of cancer cell epithelial-to-mesenchymal transition (EMT in promoting CSCs, we hypothesized that inhibition of EMT can be a useful strategy for inhibiting CSCs, and therefore a feasible approach for HTS can be built for identification of CSC inhibitors, based on assays detecting EMT inhibition.An immunofluorescent assay was established and optimized for HTS to identify compounds that enhance E-cadherin expression, as a hallmark of inhibition of EMT. Four chemical libraries containing 41,472 compounds were screened in PANC-1 pancreatic cancer cell line. Positive hits were validated for EMT and CSC inhibition in vitro using sphere formation assay, western blotting, immune fluorescence, and scratch assay.Initial hits were refined to 73 compounds with a secondary screening, among which 17 exhibited concentration dependent induction of E-cadherin expression. Six compounds were selected for further study which belonged to 2 different chemical structural clusters. A novel compound 1-(benzylsulfonyl indoline (BSI, Compound #38 significantly inhibited pancreatic cancer cell migration and invasion. BSI inhibited histone deacetylase, increased histone 4 acetylation preferably, resulting in E-cadherin up-regulation. BSI effectively inhibited tumor spheres formation. Six more analogues of BSI were tested for anti-migration and anti-CSC activities.This study demonstrated a feasible approach for discovery of agents targeting EMT and CSCs using HTS, and identified a class of novel chemicals that could be developed as anti-EMT and

  10. Oxindole based oxadiazole hybrid analogs: Novel α-glucosidase inhibitors.

    Science.gov (United States)

    Taha, Muhammad; Imran, Syahrul; Rahim, Fazal; Wadood, Abdul; Khan, Khalid Mohammed

    2018-02-01

    Inhibition of α-glucosidase is an effective strategy for controlling post-prandial hyperglycemia in diabetic patients. Beside these α-glucosidase inhibitors has been also used as anti-obesity and anti-viral drugs. Keeping in view the greater importance of α-glucosidase inhibitors here in this study we are presenting oxindole based oxadiazoles hybrid analogs (1-20) synthesis, characterized by different spectroscopic techniques including 1 H NMR and EI-MS and their α-glucosidase inhibitory activity. All compounds were found potent inhibitors for the enzyme with IC 50 values ranging between 1.25 ± 0.05 and 268.36 ± 4.22 µM when compared with the standard drug acarbose having IC 50 value 895.09 ± 2.04 µM. Our study identifies novel series of potent α-glucosidase inhibitors and further investigation on this may led to the lead compounds. A structure activity relationship has been established for all compounds. The interactions of the active compounds and enzyme active site were established with the help of molecular docking studies. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Design and Synthesis of Novel and Selective Glycine Transporter-1 (GlyT1) Inhibitors with Memory Enhancing Properties.

    Science.gov (United States)

    Santora, Vincent J; Almos, Theresa A; Barido, Richard; Basinger, Jillian; Bellows, Chris L; Bookser, Brett Carder; Breitenbucher, J Guy; Broadbent, Nicola J; Cabebe, Clifford; Chai, Chih-Kun; Chen, Mi; Chow, Stephine; Chung, De Michael; Crickard, Lindsay; Danks, Anne M; Freestone, Graeme; Gitnick, Dany; Gupta, Varsha; Hoffmaster, Christine; Hudson, Andrew R; Kaplan, Alan P; Kennedy, Michael R; Lee, Dong; Limberis, James; Ly, Kiev; Mak, Chi Ching; Masatsugu, Brittany; Morse, Andrew C; Na, Jim; Neul, David; Nikpur, John; Peters, Marco; Petroski, Robert E; Renick, Joel; Sebring, Kristen; Sevidal, Samantha; Tabatabaei, Ali; Wen, Jenny; Yan, Yingzhuo; Yoder, Zachary W; Zook, Douglas

    2018-06-11

    We report here the identification and optimization of a novel series of potent GlyT1 inhibitors. A ligand design campaign that utilized known GlyT1 inhibitors as starting points led to the identification of a novel series of pyrrolo[3,4-c]pyrazoles amides (21-50) with good in vitro potency. Subsequent optimization of physicochemical and in vitro ADME properties produced several compounds with promising pharmacokinetic profiles. In vivo inhibition of GlyT1 was demonstrated for select compounds within this series by measuring the elevation of glycine in the cerebrospinal fluid (CSF) of rats after a single oral dosing of 10 mg/kg. Ultimately, an optimized lead, compound 46, demonstrated in vivo efficacy in a rat Novel Object Recognition (NOR) assay after oral dosing at 0.1, 1, and 3 mg/kg.

  12. Estudos de QSAR 3D para um conjunto de inibidores de butirilcolinesterase humana QSAR 3D studies of a series of human butyrylcholinesterase inhibitors

    Directory of Open Access Journals (Sweden)

    Humberto F. Freitas

    2009-01-01

    Full Text Available Alzheimer's disease (AD is considered the main cause of cognitive decline in adults. The available therapies for AD treatment seek to maintain the activity of cholinergic system through the inhibition of the enzyme acetylcholinesterase. However, butyrylcholinesterase (BuChE can be considered an alternative target for AD treatment. Aiming at developing new BuChE inhibitors, robust QSAR 3D models with high predictive power were developed. The best model presents a good fit (r²=0.82, q²=0.76, with two PCs and high predictive power (r²predict=0.88. Analysis of regression vector shows that steric properties have considerable importance to the inhibition of the BuChE.

  13. Molecular modeling studies of novel retro-binding tripeptide active-site inhibitors of thrombin.

    Science.gov (United States)

    Lau, W F; Tabernero, L; Sack, J S; Iwanowicz, E J

    1995-08-01

    A novel series of retro-binding tripeptide thrombin active-site inhibitors was recently developed (Iwanowicz, E. I. et al. J. Med. Chem. 1994, 37, 2111(1)). It was hypothesized that the binding mode for these inhibitors is similar to that of the first three N-terminal residues of hirudin. This binding hypothesis was subsequently verified when the crystal structure of a member of this series, BMS-183,507 (N-[N-[N-[4-(Aminoiminomethyl)amino[-1-oxobutyl]-L- phenylalanyl]-L-allo-threonyl]-L-phenylalanine, methyl ester), was determined (Taberno, L.J. Mol. Biol. 1995, 246, 14). The methodology for developing the binding models of these inhibitors, the structure-activity relationships (SAR) and modeling studies that led to the elucidation of the proposed binding mode is described. The crystal structure of BMS-183,507/human alpha-thrombin is compared with the crystal structure of hirudin/human alpha-thrombin (Rydel, T.J. et al. Science 1990, 249,227; Rydel, T.J. et al. J. Mol Biol. 1991, 221, 583; Grutter, M.G. et al. EMBO J. 1990, 9, 2361) and with the computational binding model of BMS-183,507.

  14. Radar automatic target recognition (ATR) and non-cooperative target recognition (NCTR)

    CERN Document Server

    Blacknell, David

    2013-01-01

    The ability to detect and locate targets by day or night, over wide areas, regardless of weather conditions has long made radar a key sensor in many military and civil applications. However, the ability to automatically and reliably distinguish different targets represents a difficult challenge. Radar Automatic Target Recognition (ATR) and Non-Cooperative Target Recognition (NCTR) captures material presented in the NATO SET-172 lecture series to provide an overview of the state-of-the-art and continuing challenges of radar target recognition. Topics covered include the problem as applied to th

  15. Nuclear import inhibitor N-(4-hydroxyphenyl) retinamide targets Zika virus (ZIKV) nonstructural protein 5 to inhibit ZIKV infection.

    Science.gov (United States)

    Wang, Chunxiao; Yang, Sundy N Y; Smith, Kate; Forwood, Jade K; Jans, David A

    2017-12-02

    In the absence of approved therapeutics, Zika virus (ZIKV)'s recent prolific outbreaks in the Americas, together with impacts on unborn fetuses of infected mothers, make it a pressing human health concern worldwide. Although a key player in viral replication in the infected host cell cytoplasm, ZIKV non-structural protein 5 (NS5) appears to contribute integrally to pathogenesis by localising in the host cell nucleus, in similar fashion to NS5 from Dengue virus (DENV). We show here for the first time that ZIKV NS5 is recognized with high nanomolar affinity by the host cell importin α/β1 heterodimer, and that this interaction can be blocked by the novel DENV NS5 targeting inhibitor N-(4-hydroxyphenyl) retinamide (4-HPR). Importantly, we show that 4-HPR has potent anti-ZIKV activity at low μM concentrations. With an established safety profile for human use, 4-HPR represents an exciting possibility as an anti-ZIKV agent. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Structural characterization of nonactive site, TrkA-selective kinase inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Su, Hua-Poo; Rickert, Keith; Burlein, Christine; Narayan, Kartik; Bukhtiyarova, Marina; Hurzy, Danielle M.; Stump, Craig A.; Zhang, Xufang; Reid, John; Krasowska-Zoladek, Alicja; Tummala, Srivanya; Shipman, Jennifer M.; Kornienko, Maria; Lemaire, Peter A.; Krosky, Daniel; Heller, Amanda; Achab, Abdelghani; Chamberlin, Chad; Saradjian, Peter; Sauvagnat, Berengere; Yang, Xianshu; Ziebell, Michael R.; Nickbarg, Elliott; Sanders, John M.; Bilodeau, Mark T.; Carroll, Steven S.; Lumb, Kevin J.; Soisson, Stephen M.; Henze, Darrell A.; Cooke, Andrew J. (Merck)

    2016-12-30

    Current therapies for chronic pain can have insufficient efficacy and lead to side effects, necessitating research of novel targets against pain. Although originally identified as an oncogene, Tropomyosin-related kinase A (TrkA) is linked to pain and elevated levels of NGF (the ligand for TrkA) are associated with chronic pain. Antibodies that block TrkA interaction with its ligand, NGF, are in clinical trials for pain relief. Here, we describe the identification of TrkA-specific inhibitors and the structural basis for their selectivity over other Trk family kinases. The X-ray structures reveal a binding site outside the kinase active site that uses residues from the kinase domain and the juxtamembrane region. Three modes of binding with the juxtamembrane region are characterized through a series of ligand-bound complexes. The structures indicate a critical pharmacophore on the compounds that leads to the distinct binding modes. The mode of interaction can allow TrkA selectivity over TrkB and TrkC or promiscuous, pan-Trk inhibition. This finding highlights the difficulty in characterizing the structure-activity relationship of a chemical series in the absence of structural information because of substantial differences in the interacting residues. These structures illustrate the flexibility of binding to sequences outside of—but adjacent to—the kinase domain of TrkA. This knowledge allows development of compounds with specificity for TrkA or the family of Trk proteins.

  17. Optimization of Allosteric With-No-Lysine (WNK) Kinase Inhibitors and Efficacy in Rodent Hypertension Models

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Ken; Levell, Julian; Yoon, Taeyong; Kohls, Darcy; Yowe, David; Rigel, Dean F.; Imase, Hidetomo; Yuan, Jun; Yasoshima, Kayo; DiPetrillo, Keith; Monovich, Lauren; Xu, Lingfei; Zhu, Meicheng; Kato, Mitsunori; Jain, Monish; Idamakanti, Neeraja; Taslimi, Paul; Kawanami, Toshio; Argikar, Upendra A.; Kunjathoor, Vidya; Xie, Xiaoling; Yagi, Yukiko I.; Iwaki, Yuki; Robinson, Zachary; Park, Hyi-Man (Novartis)

    2017-08-03

    The observed structure–activity relationship of three distinct ATP noncompetitive With-No-Lysine (WNK) kinase inhibitor series, together with a crystal structure of a previously disclosed allosteric inhibitor bound to WNK1, led to an overlay hypothesis defining core and side-chain relationships across the different series. This in turn enabled an efficient optimization through scaffold morphing, resulting in compounds with a good balance of selectivity, cellular potency, and pharmacokinetic profile, which were suitable for in vivo proof-of-concept studies. When dosed orally, the optimized compound reduced blood pressure in mice overexpressing human WNK1, and induced diuresis, natriuresis and kaliuresis in spontaneously hypertensive rats (SHR), confirming that this mechanism of inhibition of WNK kinase activity is effective at regulating cardiovascular homeostasis.

  18. Drug resistance to inhibitors of the human double minute-2 E3 ligase is mediated by point mutations of p53, but can be overcome with the p53 targeting agent RITA.

    Science.gov (United States)

    Jones, Richard J; Bjorklund, Chad C; Baladandayuthapani, Veerabhadran; Kuhn, Deborah J; Orlowski, Robert Z

    2012-10-01

    The human double minute (HDM)-2 E3 ubiquitin ligase plays a key role in p53 turnover and has been validated preclinically as a target in multiple myeloma (MM) and mantle cell lymphoma (MCL). HDM-2 inhibitors are entering clinical trials, and we therefore sought to understand potential mechanisms of resistance in lymphoid models. Wild-type p53 H929 MM and Granta-519 MCL cells resistant to MI-63 or Nutlin were generated by exposing them to increasing drug concentrations. MI-63-resistant H929 and Granta-519 cells were resistant to Nutlin, whereas Nutlin-resistant cells displayed cross-resistance to MI-63. These cells also showed cross-resistance to bortezomib, doxorubicin, cisplatin, and melphalan, but remained sensitive to the small molecule inhibitor RITA (reactivation of p53 and induction of tumor cell apoptosis). HDM-2 inhibitor-resistant cells harbored increased p53 levels, but neither genotoxic nor nongenotoxic approaches to activate p53 induced HDM-2 or p21. Resequencing revealed wild-type HDM-2, but mutations were found in the p53 DNA binding and dimerization domains. In resistant cells, RITA induced a G(2)-M arrest, upregulation of p53 targets HDM-2, PUMA, and NOXA, and PARP cleavage. Combination regimens with RITA and MI-63 resulted in enhanced cell death compared with RITA alone. These findings support the possibility that p53 mutation could be a primary mechanism of acquired resistance to HDM-2 inhibitors in MCL and MM. Furthermore, they suggest that simultaneous restoration of p53 function and HDM-2 inhibition is a rational strategy for clinical translation.

  19. FGFR a promising druggable target in cancer: Molecular biology and new drugs.

    Science.gov (United States)

    Porta, Rut; Borea, Roberto; Coelho, Andreia; Khan, Shahanavaj; Araújo, António; Reclusa, Pablo; Franchina, Tindara; Van Der Steen, Nele; Van Dam, Peter; Ferri, Jose; Sirera, Rafael; Naing, Aung; Hong, David; Rolfo, Christian

    2017-05-01

    The Fibroblast Growth Factor Receptor (FGFR) family consists of Tyrosine Kinase Receptors (TKR) involved in several biological functions. Recently, alterations of FGFR have been reported to be important for progression and development of several cancers. In this setting, different studies are trying to evaluate the efficacy of different therapies targeting FGFR. This review summarizes the current status of treatments targeting FGFR, focusing on the trials that are evaluating the FGFR profile as inclusion criteria: Multi-Target, Pan-FGFR Inhibitors and anti-FGF (Fibroblast Growth Factor)/FGFR Monoclonal Antibodies. Most of the TKR share intracellular signaling pathways; therefore, cancer cells tend to overcome the inhibition of one tyrosine kinase receptor by activating another. The future of TKI (Tyrosine Kinase Inhibitor) therapy will potentially come from multi-targeted TKIs that target different TKR simultaneously. It is crucial to understand the interaction of the FGF-FGFR axis with other known driver TKRs. Based on this, it is possible to develop therapeutic strategies targeting multiple connected TKRs at once. One correct step in this direction is the reassessment of multi target inhibitors considering the FGFR status of the tumor. Another opportunity arises from assessing the use of FGFR TKI on patients harboring FGFR alterations. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Theileria Apicoplast as a Target for Chemotherapy▿ †

    OpenAIRE

    Lizundia, Regina; Werling, Dirk; Langsley, Gordon; Ralph, Stuart A.

    2008-01-01

    Theileria parasites cause severe bovine disease and death in a large part of the world. These apicomplexan parasites possess a relic plastid (apicoplast), whose metabolic pathways include several promising drug targets. Putative inhibitors of these targets were screened, and we identified antiproliferative compounds that merit further characterization.

  1. Design of novel HIV-1 protease inhibitors incorporating isophthalamide-derived P2-P3 ligands: Synthesis, biological evaluation and X-ray structural studies of inhibitor-HIV-1 protease complex

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Arun K.; Brindisi, Margherita; Nyalapatla, Prasanth R.; Takayama, Jun; Ella-Menye, Jean-Rene; Yashchuk, Sofiya; Agniswamy, Johnson; Wang, Yuan-Fang; Aoki, Manabu; Amano, Masayuki; Weber, Irene T.; Mitsuya, Hiroaki

    2017-10-01

    Based upon molecular insights from the X-ray structures of inhibitor-bound HIV-1 protease complexes, we have designed a series of isophthalamide-derived inhibitors incorporating substituted pyrrolidines, piperidines and thiazolidines as P2-P3 ligands for specific interactions in the S2-S3 extended site. Compound 4b has shown an enzyme Ki of 0.025 nM and antiviral IC50 of 69 nM. An X-ray crystal structure of inhibitor 4b-HIV-1 protease complex was determined at 1.33 Å resolution. We have also determined X-ray structure of 3b-bound HIV-1 protease at 1.27 Å resolution. These structures revealed important molecular insight into the inhibitor–HIV-1 protease interactions in the active site.

  2. Chemoproteomics-Aided Medicinal Chemistry for the Discovery of EPHA2 Inhibitors.

    Science.gov (United States)

    Heinzlmeir, Stephanie; Lohse, Jonas; Treiber, Tobias; Kudlinzki, Denis; Linhard, Verena; Gande, Santosh Lakshmi; Sreeramulu, Sridhar; Saxena, Krishna; Liu, Xiaofeng; Wilhelm, Mathias; Schwalbe, Harald; Kuster, Bernhard; Médard, Guillaume

    2017-06-21

    The receptor tyrosine kinase EPHA2 has gained attention as a therapeutic drug target for cancer and infectious diseases. However, EPHA2 research and EPHA2-based therapies have been hampered by the lack of selective small-molecule inhibitors. Herein we report the synthesis and evaluation of dedicated EPHA2 inhibitors based on the clinical BCR-ABL/SRC inhibitor dasatinib as a lead structure. We designed hybrid structures of dasatinib and the previously known EPHA2 binders CHEMBL249097, PD-173955, and a known EPHB4 inhibitor in order to exploit both the ATP pocket entrance as well as the ribose pocket as binding epitopes in the kinase EPHA2. Medicinal chemistry and inhibitor design were guided by a chemical proteomics approach, allowing early selectivity profiling of the newly synthesized inhibitor candidates. Concomitant protein crystallography of 17 inhibitor co-crystals delivered detailed insight into the atomic interactions that underlie the structure-affinity relationship. Finally, the anti-proliferative effect of the inhibitor candidates was confirmed in the glioblastoma cell line SF-268. In this work, we thus discovered a novel EPHA2 inhibitor candidate that features an improved selectivity profile while maintaining potency against EPHA2 and anticancer activity in SF-268 cells. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Saururus cernuus lignans-Potent small molecule inhibitors of hypoxia-inducible factor-1

    International Nuclear Information System (INIS)

    Hossain, Chowdhury Faiz; Kim, Yong-Pil; Baerson, Scott R.; Zhang Lei; Bruick, Richard K.; Mohammed, Kaleem A.; Agarwal, Ameeta K.; Nagle, Dale G.; Zhou Yudong

    2005-01-01

    Hypoxia-inducible factor-1 (HIF-1) represents an important tumor-selective therapeutic target for solid tumors. In search of novel small molecule HIF-1 inhibitors, 5400 natural product-rich extracts from plants, marine organisms, and microbes were examined for HIF-1 inhibitory activities using a cell-based reporter assay. Bioassay-guided fractionation and isolation, followed by structure elucidation, yielded three potent natural product-derived HIF-1 inhibitors and two structurally related inactive compounds. In a T47D cell-based reporter assay, manassantin B 1 , manassantin A, and 4-O-methylsaucerneol inhibited hypoxia-induced HIF-1 activation with IC 50 values of 3, 3, and 20 nM, respectively. All three compounds are relatively hypoxia-specific inhibitors of HIF-1 activation, in comparison to other stimuli. The hypoxic induction of HIF-1 target genes CDKN1A, VEGF, and GLUT-1 were also inhibited. These compounds inhibit HIF-1 by blocking hypoxia-induced nuclear HIF-1α protein accumulation without affecting HIF-1α mRNA levels. In addition, preliminary structure-activity studies suggest specific structural requirements for this class of HIF-1 inhibitors

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

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Fei [Department of Neurology, Sichuan Medical Science Institute and Sichuan Provincial Hospital, Chengdu 610072 (China); Li, Hongling [Department of Radiotherapy, Shanghai First People’s Hospital, Shanghai Jiao Tong University, Shanghai 201620 (China); Sun, Yong, E-mail: sunfanqi2010@163.com [Department of Burn and Plastic Surgery, Huai’an First People’s Hospital, Nanjing Medical University, Huai’an 223300 (China)

    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 effect 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.

  5. Nonstructural Proteins of Alphavirus—Potential Targets for Drug Development

    Directory of Open Access Journals (Sweden)

    Farhana Abu Bakar

    2018-02-01

    Full Text Available Alphaviruses are enveloped, positive single-stranded RNA viruses, typically transmitted by arthropods. They often cause arthralgia or encephalitic diseases in infected humans and there is currently no targeted antiviral treatment available. The re-emergence of alphaviruses in Asia, Europe, and the Americas over the last decade, including chikungunya and o’nyong’nyong viruses, have intensified the search for selective inhibitors. In this review, we highlight key molecular determinants within the alphavirus replication complex that have been identified as viral targets, focusing on their structure and functionality in viral dissemination. We also summarize recent structural data of these viral targets and discuss how these could serve as templates to facilitate structure-based drug design and development of small molecule inhibitors.

  6. CHECKPOINT INHIBITOR IMMUNE THERAPY: Systemic Indications and Ophthalmic Side Effects.

    Science.gov (United States)

    Dalvin, Lauren A; Shields, Carol L; Orloff, Marlana; Sato, Takami; Shields, Jerry A

    2018-06-01

    To review immune checkpoint inhibitor indications and ophthalmic side effects. A literature review was performed using a PubMed search for publications between 1990 and 2017. Immune checkpoint inhibitors are designed to treat system malignancies by targeting one of three ligands, leading to T-cell activation for attack against malignant cells. These ligands (and targeted drug) include cytotoxic T-lymphocyte antigen-4 (CTLA-4, ipilimumab), programmed death protein 1 (PD-1, pembrolizumab, nivolumab), and programmed death ligand-1 (PD-L1, atezolizumab, avelumab, durvalumab). These medications upregulate the immune system and cause autoimmune-like side effects. Ophthalmic side effects most frequently manifest as uveitis (1%) and dry eye (1-24%). Other side effects include myasthenia gravis (n = 19 reports), inflammatory orbitopathy (n = 11), keratitis (n = 3), cranial nerve palsy (n = 3), optic neuropathy (n = 2), serous retinal detachment (n = 2), extraocular muscle myopathy (n = 1), atypical chorioretinal lesions (n = 1), immune retinopathy (n = 1), and neuroretinitis (n = 1). Most inflammatory side effects are managed with topical or periocular corticosteroids, but advanced cases require systemic corticosteroids and cessation of checkpoint inhibitor therapy. Checkpoint inhibitors enhance the immune system by releasing inhibition on T cells, with risk of autoimmune-like side effects. Ophthalmologists should include immune-related adverse events in their differential when examining cancer patients with new ocular symptoms.

  7. Metastatic gastric cancer – focus on targeted therapies

    Directory of Open Access Journals (Sweden)

    Meza-Junco J

    2012-06-01

    Full Text Available Judith Meza-Junco, Michael B SawyerDepartment of Oncology, Cross Cancer Institute, Edmonton, Alberta, CanadaAbstract: Gastric cancer (GC is currently the second leading cause of cancer death worldwide; unfortunately, most patients will present with locally advanced or metastatic disease. Despite recent progress in diagnosis, surgery, chemotherapy, and radiotherapy, prognosis remains poor. A better understanding of GC biology and signaling pathways is expected to improve GC therapy, and the integration of targeted therapies has recently become possible and appears to be promising. This article focuses on anti-Her-2 therapy, specifically trastuzumab, as well as other epidermal growth factor receptor antagonists such as cetuximab, panitumub, matuzumab, nimotzumab, gefitinib, and erlotinib. Additionally, drugs that target angiogenesis pathways are also under investigation, particulary bevacizumab, ramucirumab, sorafenib, sunitinib, and cediranib. Other targeted agents in preclinical or early clinical development include mTOR inhibitors, anti c-MET, polo-like kinase 1 inhibitors, anti-insulin-like growth factor, anti-heat shock proteins, and small molecules targeting Hedgehog signaling.Keywords: gastric cancer, targeted therapy, antiangiogenesis drugs, anti-EGFR drugs

  8. A Pan-GTPase Inhibitor as a Molecular Probe.

    Directory of Open Access Journals (Sweden)

    Lin Hong

    Full Text Available Overactive GTPases have often been linked to human diseases. The available inhibitors are limited and have not progressed far in clinical trials. We report here a first-in-class small molecule pan-GTPase inhibitor discovered from a high throughput screening campaign. The compound CID1067700 inhibits multiple GTPases in biochemical, cellular protein and protein interaction, as well as cellular functional assays. In the biochemical and protein interaction assays, representative GTPases from Rho, Ras, and Rab, the three most generic subfamilies of the GTPases, were probed, while in the functional assays, physiological processes regulated by each of the three subfamilies of the GTPases were examined. The chemical functionalities essential for the activity of the compound were identified through structural derivatization. The compound is validated as a useful molecular probe upon which GTPase-targeting inhibitors with drug potentials might be developed.

  9. In silico search of energy metabolism inhibitors for alternative leishmaniasis treatments.

    Science.gov (United States)

    Silva, Lourival A; Vinaud, Marina C; Castro, Ana Maria; Cravo, Pedro Vítor L; Bezerra, José Clecildo B

    2015-01-01

    Leishmaniasis is a complex disease that affects mammals and is caused by approximately 20 distinct protozoa from the genus Leishmania. Leishmaniasis is an endemic disease that exerts a large socioeconomic impact on poor and developing countries. The current treatment for leishmaniasis is complex, expensive, and poorly efficacious. Thus, there is an urgent need to develop more selective, less expensive new drugs. The energy metabolism pathways of Leishmania include several interesting targets for specific inhibitors. In the present study, we sought to establish which energy metabolism enzymes in Leishmania could be targets for inhibitors that have already been approved for the treatment of other diseases. We were able to identify 94 genes and 93 Leishmania energy metabolism targets. Using each gene's designation as a search criterion in the TriTrypDB database, we located the predicted peptide sequences, which in turn were used to interrogate the DrugBank, Therapeutic Target Database (TTD), and PubChem databases. We identified 44 putative targets of which 11 are predicted to be amenable to inhibition by drugs which have already been approved for use in humans for 11 of these targets. We propose that these drugs should be experimentally tested and potentially used in the treatment of leishmaniasis.

  10. Unveiling a novel transient druggable pocket in BACE-1 through molecular simulations: Conformational analysis and binding mode of multisite inhibitors

    Science.gov (United States)

    Di Pietro, Ornella; Laughton, Charles A.

    2017-01-01

    The critical role of BACE-1 in the formation of neurotoxic ß-amyloid peptides in the brain makes it an attractive target for an efficacious treatment of Alzheimer’s disease. However, the development of clinically useful BACE-1 inhibitors has proven to be extremely challenging. In this study we examine the binding mode of a novel potent inhibitor (compound 1, with IC50 80 nM) designed by synergistic combination of two fragments—huprine and rhein—that individually are endowed with very low activity against BACE-1. Examination of crystal structures reveals no appropriate binding site large enough to accommodate 1. Therefore we have examined the conformational flexibility of BACE-1 through extended molecular dynamics simulations, paying attention to the highly flexible region shaped by loops 8–14, 154–169 and 307–318. The analysis of the protein dynamics, together with studies of pocket druggability, has allowed us to detect the transient formation of a secondary binding site, which contains Arg307 as a key residue for the interaction with small molecules, at the edge of the catalytic cleft. The formation of this druggable “floppy” pocket would enable the binding of multisite inhibitors targeting both catalytic and secondary sites. Molecular dynamics simulations of BACE-1 bound to huprine-rhein hybrid compounds support the feasibility of this hypothesis. The results provide a basis to explain the high inhibitory potency of the two enantiomeric forms of 1, together with the large dependence on the length of the oligomethylenic linker. Furthermore, the multisite hypothesis has allowed us to rationalize the inhibitory potency of a series of tacrine-chromene hybrid compounds, specifically regarding the apparent lack of sensitivity of the inhibition constant to the chemical modifications introduced in the chromene unit. Overall, these findings pave the way for the exploration of novel functionalities in the design of optimized BACE-1 multisite inhibitors

  11. Imidazole-containing farnesyltransferase inhibitors: 3D quantitative structure-activity relationships and molecular docking

    Science.gov (United States)

    Xie, Aihua; Odde, Srinivas; Prasanna, Sivaprakasam; Doerksen, Robert J.

    2009-07-01

    One of the most promising anticancer and recent antimalarial targets is the heterodimeric zinc-containing protein farnesyltransferase (FT). In this work, we studied a highly diverse series of 192 Abbott-initiated imidazole-containing compounds and their FT inhibitory activities using 3D-QSAR and docking, in order to gain understanding of the interaction of these inhibitors with FT to aid development of a rational strategy for further lead optimization. We report several highly significant and predictive CoMFA and CoMSIA models. The best model, composed of CoMFA steric and electrostatic fi