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Sample records for interaction inhibitor 4egi-1

  1. 4EGI-1 represses cap-dependent translation and regulates genome-wide translation in malignant pleural mesothelioma.

    Science.gov (United States)

    De, Arpita; Jacobson, Blake A; Peterson, Mark S; Jay-Dixon, Joe; Kratzke, Marian G; Sadiq, Ahad A; Patel, Manish R; Kratzke, Robert A

    2018-04-01

    Deregulation of cap-dependent translation has been implicated in the malignant transformation of numerous human tissues. 4EGI-1, a novel small-molecule inhibitor of cap-dependent translation, disrupts formation of the eukaryotic initiation factor 4F (eIF4F) complex. The effects of 4EGI-1-mediated inhibition of translation initiation in malignant pleural mesothelioma (MPM) were examined. 4EGI-1 preferentially inhibited cell viability and induced apoptosis in MPM cells compared to normal mesothelial (LP9) cells. This effect was associated with hypophosphorylation of 4E-binding protein 1 (4E-BP1) and decreased protein levels of the cancer-related genes, c-myc and osteopontin. 4EGI-1 showed enhanced cytotoxicity in combination with pemetrexed or gemcitabine. Translatome-wide polysome microarray analysis revealed a large cohort of genes that were translationally regulated upon treatment with 4EGI-1. The 4EGI-1-regulated translatome was negatively correlated to a previously published translatome regulated by eIF4E overexpression in human mammary epithelial cells, which is in agreement with the notion that 4EGI-1 inhibits the eIF4F complex. These data indicate that inhibition of the eIF4F complex by 4EGI-1 or similar translation inhibitors could be a strategy for treating mesothelioma. Genome wide translational profiling identified a large cohort of promising target genes that should be further evaluated for their potential significance in the treatment of MPM.

  2. Enzyme structure and interaction with inhibitors

    International Nuclear Information System (INIS)

    London, R.E.

    1983-01-01

    This article reviews some of the results of studies on the 13 C-labeled enzyme dihydrofolate reductase (DHFR). Nuclear magnetic resonance (NMR) techniques are used in combination with isotopic labeling to learn about the structure and dynamics of this enzyme. 13 C-labeling is used for the purpose of studying enzyme/substrate and enzyme/inhibitor interactions. A second set of studies with DHFR was designed to investigate the basis for the high affinity between the inhibitor methotrexate and DHFR. The label was placed on the inhibitor, rather than the enzyme

  3. Inhibitors of Ras-SOS Interactions.

    Science.gov (United States)

    Lu, Shaoyong; Jang, Hyunbum; Zhang, Jian; Nussinov, Ruth

    2016-04-19

    Activating Ras mutations are found in about 30 % of human cancers. Ras activation is regulated by guanine nucleotide exchange factors, such as the son of sevenless (SOS), which form protein-protein interactions (PPIs) with Ras and catalyze the exchange of GDP by GTP. This is the rate-limiting step in Ras activation. However, Ras surfaces lack any evident suitable pockets where a molecule might bind tightly, rendering Ras proteins still 'undruggable' for over 30 years. Among the alternative approaches is the design of inhibitors that target the Ras-SOS PPI interface, a strategy that is gaining increasing recognition for treating Ras mutant cancers. Herein we focus on data that has accumulated over the past few years pertaining to the design of small-molecule modulators or peptide mimetics aimed at the interface of the Ras-SOS PPI. We emphasize, however, that even if such Ras-SOS therapeutics are potent, drug resistance may emerge. To counteract this development, we propose "pathway drug cocktails", that is, drug combinations aimed at parallel (or compensatory) pathways. A repertoire of classified cancer, cell/tissue, and pathway/protein combinations would be beneficial toward this goal. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Proteasome inhibitor carfilzomib interacts synergistically with histone deacetylase inhibitor vorinostat in Jurkat T-leukemia cells.

    Science.gov (United States)

    Gao, Minjie; Gao, Lu; Tao, Yi; Hou, Jun; Yang, Guang; Wu, Xiaosong; Xu, Hongwei; Tompkins, Van S; Han, Ying; Wu, Huiqun; Zhan, Fenghuang; Shi, Jumei

    2014-06-01

    In the present study, we investigated the interactions between proteasome inhibitor carfilzomib (CFZ) and histone deacetylase inhibitor vorinostat in Jurkat T-leukemia cells. Coexposure of cells to minimally lethal concentrations of CFZ with very low concentration of vorinostat resulted in synergistic antiproliferative effects and enhanced apoptosis in Jurkat T-leukemia cells, accompanied with the sharply increased reactive oxygen species (ROS), the striking decrease in the mitochondrial membrane potential (MMP), the increased release of cytochrome c, the enhanced activation of caspase-9 and -3, and the cleavage of PARP. The combined treatment of Jurkat cells pre-treated with ROS scavengers N-acetylcysteine (NAC) significantly blocked the loss of mitochondrial membrane potential, suggesting that ROS generation was a former event of the loss of mitochondrial membrane potential. Furthermore, NAC also resulted in a marked reduction in apoptotic cells, indicating a critical role for increased ROS generation by combined treatment. In addition, combined treatment arrested the cell cycle in G2-M phase. These results imply that CFZ interacted synergistically with vorinostat in Jurkat T-leukemia cells, which raised the possibility that the combination of carfilzomib with vorinostat may represent a novel strategy in treating T-cell Leukemia. © The Author 2014. Published by ABBS Editorial Office in association with Oxford University Press on behalf of the Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.

  5. Rationalizing the chemical space of protein-protein interaction inhibitors.

    Science.gov (United States)

    Sperandio, Olivier; Reynès, Christelle H; Camproux, Anne-Claude; Villoutreix, Bruno O

    2010-03-01

    Protein-protein interactions (PPIs) are one of the next major classes of therapeutic targets, although they are too intricate to tackle with standard approaches. This is due, in part, to the inadequacy of today's chemical libraries. However, the emergence of a growing number of experimentally validated inhibitors of PPIs (i-PPIs) allows drug designers to use chemoinformatics and machine learning technologies to unravel the nature of the chemical space covered by the reported compounds. Key characteristics of i-PPIs can then be revealed and highlight the importance of specific shapes and/or aromatic bonds, enabling the design of i-PPI-enriched focused libraries and, therefore, of cost-effective screening strategies. 2009 Elsevier Ltd. All rights reserved.

  6. Small molecule inhibitors target the tissue transglutaminase and fibronectin interaction.

    Directory of Open Access Journals (Sweden)

    Bakhtiyor Yakubov

    Full Text Available Tissue transglutaminase (TG2 mediates protein crosslinking through generation of ε-(γ-glutamyl lysine isopeptide bonds and promotes cell adhesion through interaction with fibronectin (FN and integrins. Cell adhesion to the peritoneal matrix regulated by TG2 facilitates ovarian cancer dissemination. Therefore, disruption of the TG2-FN complex by small molecules may inhibit cell adhesion and metastasis. A novel high throughput screening (HTS assay based on AlphaLISA™ technology was developed to measure the formation of a complex between His-TG2 and the biotinylated FN fragment that binds TG2 and to discover small molecules that inhibit this protein-protein interaction. Several hits were identified from 10,000 compounds screened. The top candidates selected based on >70% inhibition of the TG2/FN complex formation were confirmed by using ELISA and bioassays measuring cell adhesion, migration, invasion, and proliferation. In conclusion, the AlphaLISA bead format assay measuring the TG2-FN interaction is robust and suitable for HTS of small molecules. One compound identified from the screen (TG53 potently inhibited ovarian cancer cell adhesion to FN, cell migration, and invasion and could be further developed as a potential inhibitor for ovarian cancer dissemination.

  7. An orthosteric inhibitor of the RAS-SOS interaction.

    Science.gov (United States)

    Nickerson, Seth; Joy, Stephen T; Arora, Paramjit S; Bar-Sagi, Dafna

    2013-01-01

    Rat sarcoma (RAS) proteins are signaling nodes that transduce extracellular cues into precise alterations in cellular physiology by engaging effector pathways. RAS signaling thus regulates diverse cell processes including proliferation, migration, differentiation, and survival. Owing to this central role in governing mitogenic signals, RAS pathway components are often dysregulated in human diseases. Targeted therapy of RAS pathways has generally not been successful, largely because of the robust biochemistry of the targets and their multifaceted network of molecular regulators. The rate-limiting step of RAS activation is Son of Sevenless (SOS)-mediated nucleotide exchange involving a single evolutionarily conserved catalytic helix from SOS. Structure function data of this mechanism provided a strong platform to design an SOS-derived, helically constrained peptide mimic as an inhibitor of the RAS-SOS interaction. In this chapter, we review RAS-SOS signaling dynamics and present evidence supporting the novel paradigm of inhibiting their interaction as a therapeutic strategy. We then describe a method of generating helically constrained peptide mimics of protein surfaces, which we have employed to inhibit the RAS-SOS active site interaction. The biochemical and functional properties of this SOS mimic support the premise that inhibition of RAS-nucleotide exchange can effectively block RAS activation and downstream signaling. © 2013 Elsevier Inc. All rights reserved.

  8. Identification of brain-specific angiogenesis inhibitor 2 as an interaction partner of glutaminase interacting protein

    International Nuclear Information System (INIS)

    Zencir, Sevil; Ovee, Mohiuddin; Dobson, Melanie J.; Banerjee, Monimoy; Topcu, Zeki; Mohanty, Smita

    2011-01-01

    Highlights: → Brain-specific angiogenesis inhibitor 2 (BAI2) is a new partner protein for GIP. → BAI2 interaction with GIP was revealed by yeast two-hybrid assay. → Binding of BAI2 to GIP was characterized by NMR, CD and fluorescence. → BAI2 and GIP binding was mediated through the C-terminus of BAI2. -- Abstract: The vast majority of physiological processes in living cells are mediated by protein-protein interactions often specified by particular protein sequence motifs. PDZ domains, composed of 80-100 amino acid residues, are an important class of interaction motif. Among the PDZ-containing proteins, glutaminase interacting protein (GIP), also known as Tax Interacting Protein TIP-1, is unique in being composed almost exclusively of a single PDZ domain. GIP has important roles in cellular signaling, protein scaffolding and modulation of tumor growth and interacts with a number of physiological partner proteins, including Glutaminase L, β-Catenin, FAS, HTLV-1 Tax, HPV16 E6, Rhotekin and Kir 2.3. To identify the network of proteins that interact with GIP, a human fetal brain cDNA library was screened using a yeast two-hybrid assay with GIP as bait. We identified brain-specific angiogenesis inhibitor 2 (BAI2), a member of the adhesion-G protein-coupled receptors (GPCRs), as a new partner of GIP. BAI2 is expressed primarily in neurons, further expanding GIP cellular functions. The interaction between GIP and the carboxy-terminus of BAI2 was characterized using fluorescence, circular dichroism (CD) and nuclear magnetic resonance (NMR) spectroscopy assays. These biophysical analyses support the interaction identified in the yeast two-hybrid assay. This is the first study reporting BAI2 as an interaction partner of GIP.

  9. Inhibitors

    Science.gov (United States)

    ... JM, and the Hemophilia Inhibitor Research Study Investigators. Validation of Nijmegen-Bethesda assay modifications to allow inhibitor ... webinars on blood disorders Language: English (US) Español (Spanish) File Formats Help: How do I view different ...

  10. 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.

  11. 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.

  12. Oligopeptidase B from Serratia proteamaculans. III. Inhibition analysis. Specific interactions with metalloproteinase inhibitors.

    Science.gov (United States)

    Mikhailova, A G; Khairullin, R F; Kolomijtseva, G Ya; Rumsh, L D

    2012-03-01

    Inhibition of the novel oligopeptidase B from Serratia proteamaculans (PSP) by basic pancreatic trypsin inhibitor, Zn2+ ions, and o- and m-phenanthroline was investigated. A pronounced effect of calcium ions on the interaction of PSP with inhibitors was demonstrated. Inversion voltamperometry and atomic absorption spectrometry revealed no zinc ions in the PSP molecule. Hydrophobic nature of the enzyme inhibition by o- and m-phenanthroline was established.

  13. Side Effects and Interactions of the Xanthine Oxidase Inhibitor Febuxostat.

    Science.gov (United States)

    Jordan, Andreas; Gresser, Ursula

    2018-05-25

    The paper addresses the safety of febuxostat and summarizes reports on side effects and interactions of febuxostat published by the cut-off date (last day of literature search) of 20 March 2018. Publications on side effects and the interactions of febuxostat were considered. Information concerning the occurrence of side effects and interactions in association with the treatment with febuxostat was collected and summarized in the review. The incidence of severe side effects was much less frequent than mild side effects (1.2⁻3.8% to 20.1⁻38.7%). The rate and range of febuxostat side effects are low at doses of up to 120 mg and only increase with a daily dose of over 120 mg. The publications reveal no age-dependent increase in side effects for febuxostat. In patients with impaired renal function, no increase in adverse events is described with a dose of up to 120 mg of febuxostat per day. Patients with impaired liver function had no elevated risk for severe side effects. A known allopurinol intolerance increases the risk of skin reactions during treatment with febuxostat by a factor of 3.6. No correlation between treatment with febuxostat and agranulocytosis has been confirmed. Possible interactions with very few medications (principally azathioprine) are known for febuxostat. Febuxostat is well tolerated and a modern and safe alternative to allopurinol therapy.

  14. 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.

  15. Small molecule inhibitors of bromodomain-acetyl-lysine interactions.

    Science.gov (United States)

    Brand, Michael; Measures, Angelina R; Measures, Angelina M; Wilson, Brian G; Cortopassi, Wilian A; Alexander, Rikki; Höss, Matthias; Hewings, David S; Rooney, Timothy P C; Paton, Robert S; Conway, Stuart J

    2015-01-16

    Bromodomains are protein modules that bind to acetylated lysine residues. Their interaction with histone proteins suggests that they function as "readers" of histone lysine acetylation, a component of the proposed "histone code". Bromodomain-containing proteins are often found as components of larger protein complexes with roles in fundamental cellular process including transcription. The publication of two potent ligands for the BET bromodomains in 2010 demonstrated that small molecules can inhibit the bromodomain-acetyl-lysine protein-protein interaction. These molecules display strong phenotypic effects in a number of cell lines and affect a range of cancers in vivo. This work stimulated intense interest in developing further ligands for the BET bromodomains and the design of ligands for non-BET bromodomains. Here we review the recent progress in the field with particular attention paid to ligand design, the assays employed in early ligand discovery, and the use of computational approaches to inform ligand design.

  16. Hot spot-based design of small-molecule inhibitors for protein-protein interactions.

    Science.gov (United States)

    Guo, Wenxing; Wisniewski, John A; Ji, Haitao

    2014-06-01

    Protein-protein interactions (PPIs) are important targets for the development of chemical probes and therapeutic agents. From the initial discovery of the existence of hot spots at PPI interfaces, it has been proposed that hot spots might provide the key for developing small-molecule PPI inhibitors. However, there has been no review on the ways in which the knowledge of hot spots can be used to achieve inhibitor design, nor critical examination of successful examples. This Digest discusses the characteristics of hot spots and the identification of druggable hot spot pockets. An analysis of four examples of hot spot-based design reveals the importance of this strategy in discovering potent and selective PPI inhibitors. A general procedure for hot spot-based design of PPI inhibitors is outlined. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Identification of Inhibitors of Biological Interactions Involving Intrinsically Disordered Proteins

    Directory of Open Access Journals (Sweden)

    Daniela Marasco

    2015-04-01

    Full Text Available Protein–protein interactions involving disordered partners have unique features and represent prominent targets in drug discovery processes. Intrinsically Disordered Proteins (IDPs are involved in cellular regulation, signaling and control: they bind to multiple partners and these high-specificity/low-affinity interactions play crucial roles in many human diseases. Disordered regions, terminal tails and flexible linkers are particularly abundant in DNA-binding proteins and play crucial roles in the affinity and specificity of DNA recognizing processes. Protein complexes involving IDPs are short-lived and typically involve short amino acid stretches bearing few “hot spots”, thus the identification of molecules able to modulate them can produce important lead compounds: in this scenario peptides and/or peptidomimetics, deriving from structure-based, combinatorial or protein dissection approaches, can play a key role as hit compounds. Here, we propose a panoramic review of the structural features of IDPs and how they regulate molecular recognition mechanisms focusing attention on recently reported drug-design strategies in the field of IDPs.

  18. Interaction of Model Inhibitor Compounds with Minimalist Cluster Representations of Hydroxyl Terminated Metal Oxide Surfaces

    Directory of Open Access Journals (Sweden)

    Christopher D. Taylor

    2018-01-01

    Full Text Available The computational modeling of corrosion inhibitors at the level of molecular interactions has been pursued for decades, and recent developments are allowing increasingly realistic models to be developed for inhibitor–inhibitor, inhibitor–solvent and inhibitor–metal interactions. At the same time, there remains a need for simplistic models to be used for the purpose of screening molecules for proposed inhibitor performance. Herein, we apply a reductionist model for metal surfaces consisting of a metal cation with hydroxide ligands and use quantum chemical modeling to approximate the free energy of adsorption for several imidazoline class candidate corrosion inhibitors. The approximation is made using the binding energy and the partition coefficient. As in some previous work, we consider different methods for incorporating solvent and reference systems for the partition coefficient. We compare the findings from this short study with some previous theoretical work on similar systems. The binding energies for the inhibitors to the metal hydroxide clusters are found to be intermediate to the binding energies calculated in other work for bare metal vs. metal oxide surfaces. The method is applied to copper, iron, aluminum and nickel metal systems.

  19. Subnanomolar Inhibitor of Cytochrome bc1 Complex Designed via Optimizing Interaction with Conformationally Flexible Residues

    Science.gov (United States)

    Zhao, Pei-Liang; Wang, Le; Zhu, Xiao-Lei; Huang, Xiaoqin; Zhan, Chang-Guo; Wu, Jia-Wei; Yang, Guang-Fu

    2009-01-01

    Cytochrome bc1 complex (EC 1.10.2.2, bc1), an essential component of the cellular respiratory chain and the photosynthetic apparatus in photosynthetic bacteria, has been identified as a promising target for new drugs and agricultural fungicides. X-ray diffraction structures of the free bc1 complex and its complexes with various inhibitors revealed that the phenyl group of Phe274 in the binding pocket exhibited significant conformational flexibility upon different inhibitors binding to optimize respective π-π interactions, whereas the side chains of other hydrophobic residues showed conformational stability. Therefore, in the present study, a strategy of optimizing the π-π interaction with conformationally flexible residues was proposed to design and discover new bc1 inhibitors with a higher potency. Eight new compounds were designed and synthesized, among which compound 5c with a Ki value of 570 pM was identified as the most promising drug or fungicide candidate, significantly more potent than the commercially available bc1 inhibitors including azoxystrobin (AZ), kresoxim-methyl (KM), and pyraclostrobin (PY). To our knowledge, this is the first bc1 inhibitor discovered from structure-based design with a potency of subnanomolar Ki value. For all of the compounds synthesized and assayed, the calculated binding free energies correlated reasonably well with the binding free energies derived from the experimental Ki values with a correlation coefficient of r2 = 0.89. The further inhibitory kinetics studies revealed that compound 5c is a non-competitive inhibitor with respect to substrate cytochrome c, but is a competitive inhibitor with respect to substrate ubiquinol. Due to its subnanomolar Ki potency and slow dissociation rate constant (k−0 = 0.00358 s−1), compound 5c could be used as a specific probe for further elucidation of the mechanism of bc1 function and as a new lead compound for future drug discovery. PMID:19928849

  20. Designing Focused Chemical Libraries Enriched in Protein-Protein Interaction Inhibitors using Machine-Learning Methods

    Science.gov (United States)

    Reynès, Christelle; Host, Hélène; Camproux, Anne-Claude; Laconde, Guillaume; Leroux, Florence; Mazars, Anne; Deprez, Benoit; Fahraeus, Robin; Villoutreix, Bruno O.; Sperandio, Olivier

    2010-01-01

    Protein-protein interactions (PPIs) may represent one of the next major classes of therapeutic targets. So far, only a minute fraction of the estimated 650,000 PPIs that comprise the human interactome are known with a tiny number of complexes being drugged. Such intricate biological systems cannot be cost-efficiently tackled using conventional high-throughput screening methods. Rather, time has come for designing new strategies that will maximize the chance for hit identification through a rationalization of the PPI inhibitor chemical space and the design of PPI-focused compound libraries (global or target-specific). Here, we train machine-learning-based models, mainly decision trees, using a dataset of known PPI inhibitors and of regular drugs in order to determine a global physico-chemical profile for putative PPI inhibitors. This statistical analysis unravels two important molecular descriptors for PPI inhibitors characterizing specific molecular shapes and the presence of a privileged number of aromatic bonds. The best model has been transposed into a computer program, PPI-HitProfiler, that can output from any drug-like compound collection a focused chemical library enriched in putative PPI inhibitors. Our PPI inhibitor profiler is challenged on the experimental screening results of 11 different PPIs among which the p53/MDM2 interaction screened within our own CDithem platform, that in addition to the validation of our concept led to the identification of 4 novel p53/MDM2 inhibitors. Collectively, our tool shows a robust behavior on the 11 experimental datasets by correctly profiling 70% of the experimentally identified hits while removing 52% of the inactive compounds from the initial compound collections. We strongly believe that this new tool can be used as a global PPI inhibitor profiler prior to screening assays to reduce the size of the compound collections to be experimentally screened while keeping most of the true PPI inhibitors. PPI-HitProfiler is

  1. Designing focused chemical libraries enriched in protein-protein interaction inhibitors using machine-learning methods.

    Directory of Open Access Journals (Sweden)

    Christelle Reynès

    2010-03-01

    Full Text Available Protein-protein interactions (PPIs may represent one of the next major classes of therapeutic targets. So far, only a minute fraction of the estimated 650,000 PPIs that comprise the human interactome are known with a tiny number of complexes being drugged. Such intricate biological systems cannot be cost-efficiently tackled using conventional high-throughput screening methods. Rather, time has come for designing new strategies that will maximize the chance for hit identification through a rationalization of the PPI inhibitor chemical space and the design of PPI-focused compound libraries (global or target-specific. Here, we train machine-learning-based models, mainly decision trees, using a dataset of known PPI inhibitors and of regular drugs in order to determine a global physico-chemical profile for putative PPI inhibitors. This statistical analysis unravels two important molecular descriptors for PPI inhibitors characterizing specific molecular shapes and the presence of a privileged number of aromatic bonds. The best model has been transposed into a computer program, PPI-HitProfiler, that can output from any drug-like compound collection a focused chemical library enriched in putative PPI inhibitors. Our PPI inhibitor profiler is challenged on the experimental screening results of 11 different PPIs among which the p53/MDM2 interaction screened within our own CDithem platform, that in addition to the validation of our concept led to the identification of 4 novel p53/MDM2 inhibitors. Collectively, our tool shows a robust behavior on the 11 experimental datasets by correctly profiling 70% of the experimentally identified hits while removing 52% of the inactive compounds from the initial compound collections. We strongly believe that this new tool can be used as a global PPI inhibitor profiler prior to screening assays to reduce the size of the compound collections to be experimentally screened while keeping most of the true PPI inhibitors. PPI

  2. Designing focused chemical libraries enriched in protein-protein interaction inhibitors using machine-learning methods.

    Science.gov (United States)

    Reynès, Christelle; Host, Hélène; Camproux, Anne-Claude; Laconde, Guillaume; Leroux, Florence; Mazars, Anne; Deprez, Benoit; Fahraeus, Robin; Villoutreix, Bruno O; Sperandio, Olivier

    2010-03-05

    Protein-protein interactions (PPIs) may represent one of the next major classes of therapeutic targets. So far, only a minute fraction of the estimated 650,000 PPIs that comprise the human interactome are known with a tiny number of complexes being drugged. Such intricate biological systems cannot be cost-efficiently tackled using conventional high-throughput screening methods. Rather, time has come for designing new strategies that will maximize the chance for hit identification through a rationalization of the PPI inhibitor chemical space and the design of PPI-focused compound libraries (global or target-specific). Here, we train machine-learning-based models, mainly decision trees, using a dataset of known PPI inhibitors and of regular drugs in order to determine a global physico-chemical profile for putative PPI inhibitors. This statistical analysis unravels two important molecular descriptors for PPI inhibitors characterizing specific molecular shapes and the presence of a privileged number of aromatic bonds. The best model has been transposed into a computer program, PPI-HitProfiler, that can output from any drug-like compound collection a focused chemical library enriched in putative PPI inhibitors. Our PPI inhibitor profiler is challenged on the experimental screening results of 11 different PPIs among which the p53/MDM2 interaction screened within our own CDithem platform, that in addition to the validation of our concept led to the identification of 4 novel p53/MDM2 inhibitors. Collectively, our tool shows a robust behavior on the 11 experimental datasets by correctly profiling 70% of the experimentally identified hits while removing 52% of the inactive compounds from the initial compound collections. We strongly believe that this new tool can be used as a global PPI inhibitor profiler prior to screening assays to reduce the size of the compound collections to be experimentally screened while keeping most of the true PPI inhibitors. PPI-HitProfiler is

  3. Interaction of amyloid inhibitor proteins with amyloid beta peptides: insight from molecular dynamics simulations.

    Directory of Open Access Journals (Sweden)

    Payel Das

    Full Text Available Knowledge of the detailed mechanism by which proteins such as human αB- crystallin and human lysozyme inhibit amyloid beta (Aβ peptide aggregation is crucial for designing treatment for Alzheimer's disease. Thus, unconstrained, atomistic molecular dynamics simulations in explicit solvent have been performed to characterize the Aβ17-42 assembly in presence of the αB-crystallin core domain and of lysozyme. Simulations reveal that both inhibitor proteins compete with inter-peptide interaction by binding to the peptides during the early stage of aggregation, which is consistent with their inhibitory action reported in experiments. However, the Aβ binding dynamics appear different for each inhibitor. The binding between crystallin and the peptide monomer, dominated by electrostatics, is relatively weak and transient due to the heterogeneous amino acid distribution of the inhibitor surface. The crystallin-bound Aβ oligomers are relatively long-lived, as they form more extensive contact surface with the inhibitor protein. In contrast, a high local density of arginines from lysozyme allows strong binding with Aβ peptide monomers, resulting in stable complexes. Our findings not only illustrate, in atomic detail, how the amyloid inhibitory mechanism of human αB-crystallin, a natural chaperone, is different from that of human lysozyme, but also may aid de novo design of amyloid inhibitors.

  4. 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.

  5. Investigation of interaction studies of cefpirome with ACE-inhibitors in various buffers

    Science.gov (United States)

    Nawaz, Muhammad; Arayne, Muhammad Saeed; Sultana, Najma; Abbas, Hira Fatima

    2015-02-01

    This work describes a RP-HPLC method for the determination and interaction studies of cefpirome with ACE-inhibitors (captopril, enalapril and lisinopril) in various buffers. The separation and interaction of cefpirome with ACE-inhibitors was achieved on a Purospher Star, C18 (5 μm, 250 × 4.6 mm) column. Mobile phase consisted of methanol: water (80:20, v/v, pH 3.3); however, for the separation of lisinopril, it was modified to methanol-water (40:60, v/v, pH 3.3) and pumped at a flow rate of 1 mL min-1. In all cases, UV detection was performed at 225 nm. Interactions were carried out in physiological pH i.e., pH 1 (simulated gastric juice), 4 (simulated full stomach), 7.4 (blood pH) and 9 (simulated GI), drug contents were analyzed by reverse phase high performance liquid chromatography. Method was found linear in the concentration range of 1.0-50.0 μg mL-1 with correlation coefficient (r2) of 0.999. Precision (RSD%) was less than 2.0%, indicating good precision of the method and accuracy was 98.0-100.0%. Furthermore, cefpirome-ACE-inhibitors' complexes were also synthesized and results were elucidated on the basis of FT-IR, and 1H NMR. The interaction results show that these interactions are pH dependent and for the co-administration of cefpirome and ACE-inhibitors, a proper interval should be given.

  6. Discovery of a small-molecule inhibitor of Dvl-CXXC5 interaction by computational approaches

    Science.gov (United States)

    Ma, Songling; Choi, Jiwon; Jin, Xuemei; Kim, Hyun-Yi; Yun, Ji-Hye; Lee, Weontae; Choi, Kang-Yell; No, Kyoung Tai

    2018-05-01

    The Wnt/β-catenin signaling pathway plays a significant role in the control of osteoblastogenesis and bone formation. CXXC finger protein 5 (CXXC5) has been recently identified as a negative feedback regulator of osteoblast differentiation through a specific interaction with Dishevelled (Dvl) protein. It was reported that targeting the Dvl-CXXC5 interaction could be a novel anabolic therapeutic target for osteoporosis. In this study, complex structure of Dvl PDZ domain and CXXC5 peptide was simulated with molecular dynamics (MD). Based on the structural analysis of binding modes of MD-simulated Dvl PDZ domain with CXXC5 peptide and crystal Dvl PDZ domain with synthetic peptide-ligands, we generated two different pharmacophore models and applied pharmacophore-based virtual screening to discover potent inhibitors of the Dvl-CXXC5 interaction for the anabolic therapy of osteoporosis. Analysis of 16 compounds selected by means of a virtual screening protocol yielded four compounds that effectively disrupted the Dvl-CXXC5 interaction in the fluorescence polarization assay. Potential compounds were validated by fluorescence spectroscopy and nuclear magnetic resonance. We successfully identified a highly potent inhibitor, BMD4722, which directly binds to the Dvl PDZ domain and disrupts the Dvl-CXXC5 interaction. Overall, CXXC5-Dvl PDZ domain complex based pharmacophore combined with various traditional and simple computational methods is a promising approach for the development of modulators targeting the Dvl-CXXC5 interaction, and the potent inhibitor BMD4722 could serve as a starting point to discover or design more potent and specific the Dvl-CXXC5 interaction disruptors.

  7. Discovery of a small-molecule inhibitor of Dvl-CXXC5 interaction by computational approaches.

    Science.gov (United States)

    Ma, Songling; Choi, Jiwon; Jin, Xuemei; Kim, Hyun-Yi; Yun, Ji-Hye; Lee, Weontae; Choi, Kang-Yell; No, Kyoung Tai

    2018-04-07

    The Wnt/β-catenin signaling pathway plays a significant role in the control of osteoblastogenesis and bone formation. CXXC finger protein 5 (CXXC5) has been recently identified as a negative feedback regulator of osteoblast differentiation through a specific interaction with Dishevelled (Dvl) protein. It was reported that targeting the Dvl-CXXC5 interaction could be a novel anabolic therapeutic target for osteoporosis. In this study, complex structure of Dvl PDZ domain and CXXC5 peptide was simulated with molecular dynamics (MD). Based on the structural analysis of binding modes of MD-simulated Dvl PDZ domain with CXXC5 peptide and crystal Dvl PDZ domain with synthetic peptide-ligands, we generated two different pharmacophore models and applied pharmacophore-based virtual screening to discover potent inhibitors of the Dvl-CXXC5 interaction for the anabolic therapy of osteoporosis. Analysis of 16 compounds selected by means of a virtual screening protocol yielded four compounds that effectively disrupted the Dvl-CXXC5 interaction in the fluorescence polarization assay. Potential compounds were validated by fluorescence spectroscopy and nuclear magnetic resonance. We successfully identified a highly potent inhibitor, BMD4722, which directly binds to the Dvl PDZ domain and disrupts the Dvl-CXXC5 interaction. Overall, CXXC5-Dvl PDZ domain complex based pharmacophore combined with various traditional and simple computational methods is a promising approach for the development of modulators targeting the Dvl-CXXC5 interaction, and the potent inhibitor BMD4722 could serve as a starting point to discover or design more potent and specific the Dvl-CXXC5 interaction disruptors.

  8. Coupled Fluid-Structure Interaction Analysis of Solid Rocket Motor with Flexible Inhibitors

    Science.gov (United States)

    Yang, H. Q.; West, Jeff; Harris, Robert E.

    2014-01-01

    Flexible inhibitors are generally used in solid rocket motors (SRMs) as a means to control the burning of propellant. Vortices generated by the flow of propellant around the flexible inhibitors have been identified as a driving source of instabilities that can lead to thrust oscillations in launch vehicles. Potential coupling between the SRM thrust oscillations and structural vibration modes is an important risk factor in launch vehicle design. As a means to predict and better understand these phenomena, a multidisciplinary simulation capability that couples the NASA production CFD code, Loci/CHEM, with CFDRC's structural finite element code, CoBi, has been developed. This capability is crucial to the development of NASA's new space launch system (SLS). This paper summarizes the efforts in applying the coupled software to demonstrate and investigate fluid-structure interaction (FSI) phenomena between pressure waves and flexible inhibitors inside reusable solid rocket motors (RSRMs). The features of the fluid and structural solvers are described in detail, and the coupling methodology and interfacial continuity requirements are then presented in a general Eulerian-Lagrangian framework. The simulations presented herein utilize production level CFD with hybrid RANS/LES turbulence modeling and grid resolution in excess of 80 million cells. The fluid domain in the SRM is discretized using a general mixed polyhedral unstructured mesh, while full 3D shell elements are utilized in the structural domain for the flexible inhibitors. Verifications against analytical solutions for a structural model under a steady uniform pressure condition and under dynamic modal analysis show excellent agreement in terms of displacement distribution and eigenmode frequencies. The preliminary coupled results indicate that due to acoustic coupling, the dynamics of one of the more flexible inhibitors shift from its first modal frequency to the first acoustic frequency of the solid rocket motor

  9. Evaluation of potential interactions between mycophenolic acid derivatives and proton pump inhibitors.

    Science.gov (United States)

    Gabardi, Steven; Olyaei, Ali

    2012-01-01

    To evaluate the incidence of gastrointestinal (GI) complications in solid organ transplant (SOT) recipients, impact of the complications on transplant outcomes, and the potential interactions between mycophenolic acid (MPA) derivatives and proton pump inhibitors (PPIs). An unrestricted literature search (1980-January 2012) was performed with MEDLINE and EMBASE using the following key words: drug-drug interaction, enteric-coated mycophenolic acid, GI complications, mycophenolate mofetil, solid organ transplant, and proton pump inhibitor, including individual agents within the class. Abstracts from scientific meetings were also evaluated. Additionally, reference citations from identified publications were reviewed. Relevant English-language, original research articles and review articles were evaluated if they focused on any of the topics identified in the search or included substantial content addressing GI complications in SOT recipients or drug interactions. GI complications are frequent among SOT recipients, with some studies showing prevalence rates as high as 70%. Transplant outcomes among renal transplant recipients are significantly impacted by GI complications, especially in patients requiring immunosuppressant dosage reductions or premature discontinuation. To this end, PPI use among patients receiving transplants is common. Recent data demonstrate that PPIs significantly reduce the overall exposure to MPA after oral administration of mycophenolate mofetil. Similar studies show this interaction does not exist between PPIs and enteric-coated mycophenolic acid (EC-MPA). Unfortunately, most of the available data evaluating this interaction are pharmacokinetic analyses that do not investigate the clinical impact of this interaction. A significant interaction exists between PPIs and mycophenolate mofetil secondary to reduced dissolution of mycophenolate mofetil in higher pH environments. EC-MPA is not absorbed in the stomach; therefore, low intragastric acidity

  10. 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.

  11. Interaction of small molecule inhibitors of HIV-1 entry with CCR5

    International Nuclear Information System (INIS)

    Seibert, Christoph; Ying Weiwen; Gavrilov, Svetlana; Tsamis, Fotini; Kuhmann, Shawn E.; Palani, Anandan; Tagat, Jayaram R.; Clader, John W.; McCombie, Stuart W.; Baroudy, Bahige M.; Smith, Steven O.; Dragic, Tatjana; Moore, John P.; Sakmar, Thomas P.

    2006-01-01

    The CC-chemokine receptor 5 (CCR5) is the major coreceptor for macrophage-tropic (R5) HIV-1 strains. Several small molecule inhibitors of CCR5 that block chemokine binding and HIV-1 entry are being evaluated as drug candidates. Here we define how CCR5 antagonists TAK-779, AD101 (SCH-350581) and SCH-C (SCH-351125), which inhibit HIV-1 entry, interact with CCR5. Using a mutagenesis approach in combination with a viral entry assay to provide a direct functional read out, we tested predictions based on a homology model of CCR5 and analyzed the functions of more than 30 amino acid residues. We find that a key set of aromatic and aliphatic residues serves as a hydrophobic core for the ligand binding pocket, while E283 is critical for high affinity interaction, most likely by acting as the counterion for a positively charged nitrogen atom common to all three inhibitors. These results provide a structural basis for understanding how specific antagonists interact with CCR5, and may be useful for the rational design of new, improved CCR5 ligands

  12. Fibulin-1C, C1 esterase inhibitor and glucose regulated protein 75 interact with the CREC proteins, calumenin and reticulocalbin

    DEFF Research Database (Denmark)

    Hansen, Gry Aune Westergaard; Ludvigsen, Maja; Jacobsen, Christian

    2015-01-01

    Affinity purification, immunoprecipitation, gel electrophoresis and mass spectrometry were used to identify fibulin-1C, C1 esterase inhibitor and glucose regulated protein 75, grp75, as binding partners of the CREC proteins, calumenin and reticulocalbin. Surface plasmon resonance was used to verify...... the interaction of all three proteins with each of the CREC proteins. Fibulin-1C interacts with calumenin and reticulocalbin with an estimated dissociation constant around 50-60 nM. The interaction, at least for reticulocalbin, was not dependent upon the presence of Ca2+. C1 esterase inhibitor interacted...

  13. A Coupled Fluid-Structure Interaction Analysis of Solid Rocket Motor with Flexible Inhibitors

    Science.gov (United States)

    Yang, H. Q.; West, Jeff

    2014-01-01

    A capability to couple NASA production CFD code, Loci/CHEM, with CFDRC's structural finite element code, CoBi, has been developed. This paper summarizes the efforts in applying the installed coupling software to demonstrate/investigate fluid-structure interaction (FSI) between pressure wave and flexible inhibitor inside reusable solid rocket motor (RSRM). First a unified governing equation for both fluid and structure is presented, then an Eulerian-Lagrangian framework is described to satisfy the interfacial continuity requirements. The features of fluid solver, Loci/CHEM and structural solver, CoBi, are discussed before the coupling methodology of the solvers is described. The simulation uses production level CFD LES turbulence model with a grid resolution of 80 million cells. The flexible inhibitor is modeled with full 3D shell elements. Verifications against analytical solutions of structural model under steady uniform pressure condition and under dynamic condition of modal analysis show excellent agreements in terms of displacement distribution and eigen modal frequencies. The preliminary coupled result shows that due to acoustic coupling, the dynamics of one of the more flexible inhibitors shift from its first modal frequency to the first acoustic frequency of the solid rocket motor.

  14. Interaction of fucoidan with proteases and inhibitors of coagulation and fibrinolysis.

    Science.gov (United States)

    Minix, R; Doctor, V M

    1997-09-01

    The interactions of fucoidan with glutamic plasminogen (Glu-Plg), two-chain tissue plasminogen activator (t-PA), LMwt-urokinase, thrombin, and antithrombin III (AT-III) were investigated using fucoidan-sepharose affinity chromatography. The results showed 1) a high degree of affinity between fucoidan-sepharose and Glu-Plg; Lmwt-urokinase and thrombin while t-Pa and AT-III did not bind with fucoidan-sepharose. 2) The double reciprocal plot for the LMwt-urokinase activation of Glu-Plg showed that plasminogen activator inhibitor (PAI-1) inhibited this reaction in a noncompetitive manner and that the presence of fucoidan decreased Km for this interaction by 50% and increased Kcat by 30-fold, 3) The double reciprocal plot for the t-PA activation of Glu-Plg showed that PAI-1 inhibited this reaction in a competitive manner and that fucoidan in conjunction with 6-aminohexanoic acid (6-AH) increased Kcat for this interaction by 5-fold without affecting Km. 4) Fucoidan enhanced the interaction of thrombin with both AT-III and heparin cofactor II (HC-II) and it was more effective than unfractionated heparin of LMwt-heparin in enhancing the interaction of HC-II with thrombin.

  15. The kinetics of interaction of porcine - alpha-, and porcine - beta -trypsin with intact and modified soybean trypsin inhibitor (kunitz)

    International Nuclear Information System (INIS)

    Hamid, M.A.

    1994-01-01

    The association of porcine trypsin with soybean trypsin inhibitor (Kunitz) resulted in characteristic changes in absorption spectrum, indicating an alteration of the micro environments of the enzyme chromophores as a consequence of the interaction. The rates of formation of the stable trypsin - inhibitor complexes from porcine - alpha - trypsin and soybean trypsin inhibitor and from porcine - beta - trypsin and either intact or modified soybean trypsin inhibitor were measured by mixing the equimolar concentration of the reactants in a Stopped - Flow apparatus at pH (4.5 to 10.0). The reaction of trypsin with soybean trypsin inhibitor was of first order with respect to the concentration of the reactants used. The rates of dissociation of the stable complexes, alpha - trypsin - soybean trypsin inhibitor, beta -trypsin - soybean trypsin inhibitor and beta -trypsin modified soybean trypsin inhibitor were also measured at pH (1.92 to 3.58). The values of first order rate constant, k/sub D/ obtained for the dissociation of all the three complexes were identical with one another. The kinetics results obtained for the porcine trypsin were compared with those of bovine trypsin system and it was suggested that the reaction mechanisms in both these systems were identical. (author)

  16. The EED protein–protein interaction inhibitor A-395 inactivates the PRC2 complex

    Energy Technology Data Exchange (ETDEWEB)

    He, Yupeng; Selvaraju, Sujatha; Curtin, Michael L.; Jakob, Clarissa G.; Zhu, Haizhong; Comess, Kenneth M.; Shaw, Bailin; The, Juliana; Lima-Fernandes, Evelyne; Szewczyk, Magdalena M.; Cheng, Dong; Klinge, Kelly L.; Li, Huan-Qiu; Pliushchev, Marina; Algire, Mikkel A.; Maag, David; Guo, Jun; Dietrich, Justin; Panchal, Sanjay C.; Petros, Andrew M.; Sweis, Ramzi F.; Torrent, Maricel; Bigelow, Lance J.; Senisterra, Guillermo; Li, Fengling; Kennedy, Steven; Wu, Qin; Osterling, Donald J.; Lindley, David J.; Gao, Wenqing; Galasinski, Scott; Barsyte-Lovejoy, Dalia; Vedadi, Masoud; Buchanan, Fritz G.; Arrowsmith, Cheryl H.; Chiang, Gary G.; Sun, Chaohong; Pappano , William N. (AbbVie); (Toronto)

    2017-01-30

    Polycomb repressive complex 2 (PRC2) is a regulator of epigenetic states required for development and homeostasis. PRC2 trimethylates histone H3 at lysine 27 (H3K27me3), which leads to gene silencing, and is dysregulated in many cancers. The embryonic ectoderm development (EED) protein is an essential subunit of PRC2 that has both a scaffolding function and an H3K27me3-binding function. Here we report the identification of A-395, a potent antagonist of the H3K27me3 binding functions of EED. Structural studies demonstrate that A-395 binds to EED in the H3K27me3-binding pocket, thereby preventing allosteric activation of the catalytic activity of PRC2. Phenotypic effects observed in vitro and in vivo are similar to those of known PRC2 enzymatic inhibitors; however, A-395 retains potent activity against cell lines resistant to the catalytic inhibitors. A-395 represents a first-in-class antagonist of PRC2 protein–protein interactions (PPI) for use as a chemical probe to investigate the roles of EED-containing protein complexes.

  17. Interaction of protein C inhibitor with the type II transmembrane serine protease enteropeptidase.

    Directory of Open Access Journals (Sweden)

    Thomas A Prohaska

    Full Text Available The serine protease inhibitor protein C inhibitor (PCI is expressed in many human tissues and exhibits broad protease reactivity. PCI binds glycosaminoglycans and certain phospholipids, which modulate its inhibitory activity. Enteropeptidase (EP is a type II transmembrane serine protease mainly found on the brush border membrane of epithelial cells in the duodenum, where it activates trypsinogen to initiate the digestion of food proteins. Some active EP is also present in duodenal fluid and has been made responsible for causing pancreatitis in case of duodeno-pancreatic reflux. Together with its substrate trypsinogen, EP is furthermore present in the epidermis and in some cancer cells. In this report, we show that PCI inhibited EP with an apparent 2nd order rate constant of 4.48 × 10(4 M(-1 s(-1. Low molecular weight (LMWH and unfractionated heparin (UFH slightly reduced the inhibitory effect of PCI. The SI (stoichiometry of inhibition value for the inhibition of EP by PCI was 10.8 in the absence and 17.9 in the presence of UFH (10 U/ml. By inhibiting trypsin, chymotrypsin, and additionally EP, PCI might play a role in the protection of the pancreas from autodigestion. Furthermore the interaction of PCI with EP may influence the regulation of epithelial differentiation.

  18. Molecular interaction of 2-mercaptobenzimidazole with catalase reveals a potentially toxic mechanism of the inhibitor.

    Science.gov (United States)

    Teng, Yue; Zou, Luyi; Huang, Ming; Zong, Wansong

    2014-12-01

    2-Mercaptobenzimidazole (MBI) is widely utilized as a corrosion inhibitor, copper-plating brightener and rubber accelerator. The residue of MBI in the environment possesses a potential risk to human health. In this work, the toxic interaction of MBI with the important antioxidant enzyme catalase (CAT) was investigated using spectroscopic and molecular docking methods under physiological conditions. MBI can spontaneously bind with CAT with one binding site through hydrogen bonds and van der Waals forces to form MBI-CAT complex. The molecular docking study revealed that MBI bound into the CAT interface of chains B and C, which led to some conformational and microenvironmental changes of CAT and further resulted in the inhibition of CAT activity. This present study provides direct evidence at a molecular level to show that exposure to MBI could induce changes in the structure and function of the enzyme CAT. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. The potential drug-drug interaction between proton pump inhibitors and warfarin

    DEFF Research Database (Denmark)

    Henriksen, Daniel Pilsgaard; Stage, Tore Bjerregaard; Hansen, Morten Rix

    2015-01-01

    BACKGROUND: Proton pump inhibitors (PPIs) have been suggested to increase the effect of warfarin, and clinical guidelines recommend careful monitoring of international normalized ratio (INR) when initiating PPI among warfarin users. However, this drug-drug interaction is sparsely investigated...... in a clinical setting. The aim was to assess whether initiation of PPI treatment among users of warfarin leads to increased INR values. METHODS: The study was an observational self-controlled study from 1998 to 2012 leveraging data on INR measurements on patients treated with warfarin from primary care...... and outpatient clinics and their use of prescription drugs. Data were analyzed in 2015. We assessed INR, warfarin dose, and dose/INR ratio before and after initiating PPI treatment using the paired student's t-test. RESULTS: We identified 305 warfarin users initiating treatment with PPIs. The median age was 71...

  20. A lanthipeptide library used to identify a protein-protein interaction inhibitor.

    Science.gov (United States)

    Yang, Xiao; Lennard, Katherine R; He, Chang; Walker, Mark C; Ball, Andrew T; Doigneaux, Cyrielle; Tavassoli, Ali; van der Donk, Wilfred A

    2018-04-01

    In this article we describe the production and screening of a genetically encoded library of 10 6 lanthipeptides in Escherichia coli using the substrate-tolerant lanthipeptide synthetase ProcM. This plasmid-encoded library was combined with a bacterial reverse two-hybrid system for the interaction of the HIV p6 protein with the UEV domain of the human TSG101 protein, which is a critical protein-protein interaction for HIV budding from infected cells. Using this approach, we identified an inhibitor of this interaction from the lanthipeptide library, whose activity was verified in vitro and in cell-based virus-like particle-budding assays. Given the variety of lanthipeptide backbone scaffolds that may be produced with ProcM, this method may be used for the generation of genetically encoded libraries of natural product-like lanthipeptides containing substantial structural diversity. Such libraries may be combined with any cell-based assay to identify lanthipeptides with new biological activities.

  1. Homology modeling of Leishmania donovani enolase and its molecular interaction with novel inhibitors

    Directory of Open Access Journals (Sweden)

    Jay Prakash Mahato

    2017-01-01

    Full Text Available Introduction: The treatment of Indian tropical disease such as kala-azar is likely to be troublesome to the clinicians as AmpB- and miltefosine-resistant Leishmania donovani has been reported. The rationale behind designed a novel inhibitors of model of L. donovani enolase and performing a binding study with its inhibitors to gain details of the interaction between protein residues and ligand molecules. Methods and Materials: The L. donovani enolase model consists of two typical domains. The N-terminal one contains three-stranded antiparallel β-sheets, followed by six α-helices. The C-terminal domain composes of eleven-stranded mixed α/β-barrel with connectivity. The first α-helix within the C-terminal domain, H7, and the second β-strand, S7, of the barrel domain was arranged in an antiparallel fashion compared to all other α-helices and β-strands. The root-mean-square deviation between predicted model and template is 0.4 Å. The overall conformation of L. donovani enolase model is similar to those of Trypanosoma cruzi enolase and Streptococcus pneumoniae enolase crystal structures. Result: The key amino acid residues within the docking complex model involved in the interaction between model enolase structure and ligand molecule are Lys70, Asn165, Ala168, Asp17, and Asn213. Conclusion: Our theoretical prediction may lead to the establishment of prophylactic and therapeutic approaches for the treatment of kala-azar. This biomedical informatics analysis will help us to combat future kala-azar.

  2. Surfing the Protein-Protein Interaction Surface Using Docking Methods: Application to the Design of PPI Inhibitors

    Directory of Open Access Journals (Sweden)

    Rushikesh Sable

    2015-06-01

    Full Text Available Blocking protein-protein interactions (PPI using small molecules or peptides modulates biochemical pathways and has therapeutic significance. PPI inhibition for designing drug-like molecules is a new area that has been explored extensively during the last decade. Considering the number of available PPI inhibitor databases and the limited number of 3D structures available for proteins, docking and scoring methods play a major role in designing PPI inhibitors as well as stabilizers. Docking methods are used in the design of PPI inhibitors at several stages of finding a lead compound, including modeling the protein complex, screening for hot spots on the protein-protein interaction interface and screening small molecules or peptides that bind to the PPI interface. There are three major challenges to the use of docking on the relatively flat surfaces of PPI. In this review we will provide some examples of the use of docking in PPI inhibitor design as well as its limitations. The combination of experimental and docking methods with improved scoring function has thus far resulted in few success stories of PPI inhibitors for therapeutic purposes. Docking algorithms used for PPI are in the early stages, however, and as more data are available docking will become a highly promising area in the design of PPI inhibitors or stabilizers.

  3. Surfing the Protein-Protein Interaction Surface Using Docking Methods: Application to the Design of PPI Inhibitors.

    Science.gov (United States)

    Sable, Rushikesh; Jois, Seetharama

    2015-06-23

    Blocking protein-protein interactions (PPI) using small molecules or peptides modulates biochemical pathways and has therapeutic significance. PPI inhibition for designing drug-like molecules is a new area that has been explored extensively during the last decade. Considering the number of available PPI inhibitor databases and the limited number of 3D structures available for proteins, docking and scoring methods play a major role in designing PPI inhibitors as well as stabilizers. Docking methods are used in the design of PPI inhibitors at several stages of finding a lead compound, including modeling the protein complex, screening for hot spots on the protein-protein interaction interface and screening small molecules or peptides that bind to the PPI interface. There are three major challenges to the use of docking on the relatively flat surfaces of PPI. In this review we will provide some examples of the use of docking in PPI inhibitor design as well as its limitations. The combination of experimental and docking methods with improved scoring function has thus far resulted in few success stories of PPI inhibitors for therapeutic purposes. Docking algorithms used for PPI are in the early stages, however, and as more data are available docking will become a highly promising area in the design of PPI inhibitors or stabilizers.

  4. 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

  5. Intracellular antibody capture: A molecular biology approach to inhibitors of protein-protein interactions.

    Science.gov (United States)

    Zhang, Jing; Rabbitts, Terence H

    2014-11-01

    Many proteins of interest in basic biology, translational research studies and for clinical targeting in diseases reside inside the cell and function by interacting with other macromolecules. Protein complexes control basic processes such as development and cell division but also abnormal cell growth when mutations occur such as found in cancer. Interfering with protein-protein interactions is an important aspiration in both basic and disease biology but small molecule inhibitors have been difficult and expensive to isolate. Recently, we have adapted molecular biology techniques to develop a simple set of protocols for isolation of high affinity antibody fragments (in the form of single VH domains) that function within the reducing environment of higher organism cells and can bind to their target molecules. The method called Intracellular Antibody Capture (IAC) has been used to develop inhibitory anti-RAS and anti-LMO2 single domains that have been used for target validation of these antigens in pre-clinical cancer models and illustrate the efficacy of the IAC approach to generation of drug surrogates. Future use of inhibitory VH antibody fragments as drugs in their own right (we term these macrodrugs to distinguish them from small molecule drugs) requires their delivery to target cells in vivo but they can also be templates for small molecule drug development that emulate the binding sites of the antibody fragments. This article is part of a Special Issue entitled: Recent advances in molecular engineering of antibody. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Protease Inhibitors in Tick Saliva: The Role of Serpins and Cystatins in Tick-host-Pathogen Interaction

    Czech Academy of Sciences Publication Activity Database

    Chmelař, J.; Kotál, Jan; Langhansová, Helena; Kotsyfakis, Michalis

    2017-01-01

    Roč. 7, MAY 29 (2017), č. článku 276. ISSN 2235-2988 Institutional support: RVO:60077344 Keywords : tick-host interaction * immunomodulation * protease inhibitors * serpins * cystatins Subject RIV: EC - Immunology OBOR OECD: Immunology Impact factor: 4.300, year: 2016

  7. Analysis of the interaction between the aspartic peptidase inhibitor SQAPI and aspartic peptidases using surface plasmon resonance.

    Science.gov (United States)

    Farley, Peter C; Christeller, John T; Sullivan, Michelle E; Sullivan, Patrick A; Laing, William A

    2002-01-01

    Aspartic peptidase inhibitors, which are themselves proteins, are strong inhibitors (small inhibition constants) of some aspartic peptidases but not others. However, there have been no studies of the kinetics of the interaction between a proteinaceous aspartic peptidase inhibitor and aspartic peptidases. This paper describes an analysis of rate constants for the interaction between recombinant squash aspartic peptidase inhibitor (rSQAPI) and a panel of aspartic peptidases that have a range of inhibition constants for SQAPI. Purified rSQAPI completely inhibits pepsin at a 1:1 molar ratio of pepsin to rSQAPI monomer (inhibition constant 1 nM). The interaction of pepsin with immobilized rSQAPI, at pH values between 3.0 and 6.0, was monitored using surface plasmon resonance. Binding of pepsin to rSQAPI was slow (association rate constants ca 10(4)M (-1)s(-1)), but rSQAPI was an effective pepsin inhibitor because dissociation of the rSQAPI-pepsin complex was much slower (dissociation rate constants ca 10(-4)s(-1)), especially at low pH values. Similar results were obtained with a His-tagged rSQAPI. Strong inhibition (inhibition constant 3 nM) of one isoform (rSap4) of the family of Candida albicans-secreted aspartic peptidases was, as with pepsin, characterized by slow binding of rSap4 and slower dissociation of the rSap4-inhibitor complex. In contrast, weaker inhibition of the Glomerella cingulata-secreted aspartic peptidase (inhibition constant 7 nM) and the C. albicans rSap1 and Sap2 isoenzymes (inhibition constants 25 and 400 nM, respectively) was, in each case, characterized by a larger dissociation rate constant. Copyright 2002 John Wiley & Sons, Ltd.

  8. 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.

  9. Genotoxicity studies on DNA-interactive telomerase inhibitors with application as anti-cancer agents.

    Science.gov (United States)

    Harrington, Dean J; Cemeli, Eduardo; Carder, Joanna; Fearnley, Jamie; Estdale, Sian; Perry, Philip J; Jenkins, Terence C; Anderson, Diana

    2003-01-01

    Telomerase-targeted strategies have aroused recent interest in anti-cancer chemotherapy, because DNA-binding drugs can interact with high-order tetraplex rather than double-stranded (duplex) DNA targets in tumour cells. However, the protracted cell-drug exposure times necessary for clinical application require that telomerase inhibitory efficacy must be accompanied by both low inherent cytotoxicity and the absence of mutagenicity/genotoxicity. For the first time, the genotoxicity of a number of structurally diverse DNA-interactive telomerase inhibitors is examined in the Ames test using six Salmonella typhimurium bacterial strains (TA1535, TA1537, TA1538, TA98, TA100, and TA102). DNA damage induced by each agent was also assessed using the Comet assay with human lymphocytes. The two assay procedures revealed markedly different genotoxicity profiles that are likely to reflect differences in metabolism and/or DNA repair between bacterial and mammalian cells. The mutational spectrum for a biologically active fluorenone derivative, shown to be mutagenic in the TA100 strain, was characterised using a novel and rapid assay method based upon PCR amplification of a fragment of the hisG46 allele, followed by RFLP analysis. Preliminary analysis indicates that the majority (84%) of mutations induced by this compound are C --> A transversions at position 2 of the missense proline codon of the hisG46 allele. However, despite its genotoxic bacterial profile, this fluorenone agent gave a negative response in the Comet assay, and demonstrates how unwanted systemic effects (e.g., cytotoxicity and genotoxicity) can be prevented or ameliorated through suitable molecular fine-tuning of a candidate drug in targeted human tumour cells. Copyright 2003 Wiley-Liss, Inc.

  10. Fibulin-1C, C1 Esterase Inhibitor and Glucose Regulated Protein 75 Interact with the CREC Proteins, Calumenin and Reticulocalbin.

    Directory of Open Access Journals (Sweden)

    Gry Aune Westergaard Hansen

    Full Text Available Affinity purification, immunoprecipitation, gel electrophoresis and mass spectrometry were used to identify fibulin-1C, C1 esterase inhibitor and glucose regulated protein 75, grp75, as binding partners of the CREC proteins, calumenin and reticulocalbin. Surface plasmon resonance was used to verify the interaction of all three proteins with each of the CREC proteins. Fibulin-1C interacts with calumenin and reticulocalbin with an estimated dissociation constant around 50-60 nM. The interaction, at least for reticulocalbin, was not dependent upon the presence of Ca2+. C1 esterase inhibitor interacted with both proteins with an estimated dissociation constant at 1 μM for reticulocalbin and 150 nM for calumenin. The interaction, at least for calumenin, was dependent upon the presence of Ca2+ with strong interaction at 3.5 mM while no detectable interaction could be found at 0.1 mM. Grp75 binds with an affinity of approximately 3-7 nM with reticulocalbin as well as with calumenin. These interactions suggest functional participation of the CREC proteins in chaperone activity, cell proliferation and transformation, cellular aging, haemostasis and thrombosis as well as modulation of the complement system in fighting bacterial infection.

  11. Stapled Voltage-Gated Calcium Channel (CaV) α-Interaction Domain (AID) Peptides Act As Selective Protein-Protein Interaction Inhibitors of CaV Function.

    Science.gov (United States)

    Findeisen, Felix; Campiglio, Marta; Jo, Hyunil; Abderemane-Ali, Fayal; Rumpf, Christine H; Pope, Lianne; Rossen, Nathan D; Flucher, Bernhard E; DeGrado, William F; Minor, Daniel L

    2017-06-21

    For many voltage-gated ion channels (VGICs), creation of a properly functioning ion channel requires the formation of specific protein-protein interactions between the transmembrane pore-forming subunits and cystoplasmic accessory subunits. Despite the importance of such protein-protein interactions in VGIC function and assembly, their potential as sites for VGIC modulator development has been largely overlooked. Here, we develop meta-xylyl (m-xylyl) stapled peptides that target a prototypic VGIC high affinity protein-protein interaction, the interaction between the voltage-gated calcium channel (Ca V ) pore-forming subunit α-interaction domain (AID) and cytoplasmic β-subunit (Ca V β). We show using circular dichroism spectroscopy, X-ray crystallography, and isothermal titration calorimetry that the m-xylyl staples enhance AID helix formation are structurally compatible with native-like AID:Ca V β interactions and reduce the entropic penalty associated with AID binding to Ca V β. Importantly, electrophysiological studies reveal that stapled AID peptides act as effective inhibitors of the Ca V α 1 :Ca V β interaction that modulate Ca V function in an Ca V β isoform-selective manner. Together, our studies provide a proof-of-concept demonstration of the use of protein-protein interaction inhibitors to control VGIC function and point to strategies for improved AID-based Ca V modulator design.

  12. Synergistic interactions between HDAC and sirtuin inhibitors in human leukemia cells.

    Directory of Open Access Journals (Sweden)

    Michele Cea

    Full Text Available Aberrant histone deacetylase (HDAC activity is frequent in human leukemias. However, while classical, NAD(+-independent HDACs are an established therapeutic target, the relevance of NAD(+-dependent HDACs (sirtuins in leukemia treatment remains unclear. Here, we assessed the antileukemic activity of sirtuin inhibitors and of the NAD(+-lowering drug FK866, alone and in combination with traditional HDAC inhibitors. Primary leukemia cells, leukemia cell lines, healthy leukocytes and hematopoietic progenitors were treated with sirtuin inhibitors (sirtinol, cambinol, EX527 and with FK866, with or without addition of the HDAC inhibitors valproic acid, sodium butyrate, and vorinostat. Cell death was quantified by propidium iodide cell staining and subsequent flow-cytometry. Apoptosis induction was monitored by cell staining with FITC-Annexin-V/propidium iodide or with TMRE followed by flow-cytometric analysis, and by measuring caspase3/7 activity. Intracellular Bax was detected by flow-cytometry and western blotting. Cellular NAD(+ levels were measured by enzymatic cycling assays. Bax was overexpressed by retroviral transduction. Bax and SIRT1 were silenced by RNA-interference. Sirtuin inhibitors and FK866 synergistically enhanced HDAC inhibitor activity in leukemia cells, but not in healthy leukocytes and hematopoietic progenitors. In leukemia cells, HDAC inhibitors were found to induce upregulation of Bax, a pro-apoptotic Bcl2 family-member whose translocation to mitochondria is normally prevented by SIRT1. As a result, leukemia cells become sensitized to sirtuin inhibitor-induced apoptosis. In conclusion, NAD(+-independent HDACs and sirtuins cooperate in leukemia cells to avoid apoptosis. Combining sirtuin with HDAC inhibitors results in synergistic antileukemic activity that could be therapeutically exploited.

  13. HAEdb: a novel interactive, locus-specific mutation database for the C1 inhibitor gene.

    Science.gov (United States)

    Kalmár, Lajos; Hegedüs, Tamás; Farkas, Henriette; Nagy, Melinda; Tordai, Attila

    2005-01-01

    Hereditary angioneurotic edema (HAE) is an autosomal dominant disorder characterized by episodic local subcutaneous and submucosal edema and is caused by the deficiency of the activated C1 esterase inhibitor protein (C1-INH or C1INH; approved gene symbol SERPING1). Published C1-INH mutations are represented in large universal databases (e.g., OMIM, HGMD), but these databases update their data rather infrequently, they are not interactive, and they do not allow searches according to different criteria. The HAEdb, a C1-INH gene mutation database (http://hae.biomembrane.hu) was created to contribute to the following expectations: 1) help the comprehensive collection of information on genetic alterations of the C1-INH gene; 2) create a database in which data can be searched and compared according to several flexible criteria; and 3) provide additional help in new mutation identification. The website uses MySQL, an open-source, multithreaded, relational database management system. The user-friendly graphical interface was written in the PHP web programming language. The website consists of two main parts, the freely browsable search function, and the password-protected data deposition function. Mutations of the C1-INH gene are divided in two parts: gross mutations involving DNA fragments >1 kb, and micro mutations encompassing all non-gross mutations. Several attributes (e.g., affected exon, molecular consequence, family history) are collected for each mutation in a standardized form. This database may facilitate future comprehensive analyses of C1-INH mutations and also provide regular help for molecular diagnostic testing of HAE patients in different centers.

  14. The cannabinoid transporter inhibitor OMDM-2 reduces social interaction: Further evidence for transporter-mediated endocannabinoid release.

    Science.gov (United States)

    Seillier, Alexandre; Giuffrida, Andrea

    2018-03-01

    Experimental evidence suggests that the transport of endocannabinoids might work bi-directionally. Accordingly, it is possible that pharmacological blockade of the latter affects not only the re-uptake, but also the release of endocannabinoids, thus preventing them from stimulating CB 1 receptors. We used biochemical, pharmacological, and behavioral approaches to investigate the effects of the transporter inhibitor OMDM-2 on social interaction, a behavioral assay that requires activation of CB 1 receptors. The underlying mechanisms of OMDM-2 were compared with those of the Fatty Acid Amide Hydrolase (FAAH) inhibitor URB597. Systemic administration of OMDM-2 reduced social interaction, but in contrast to URB597-induced social deficit, this effect was not reversed by the TRPV1 antagonist capsazepine. The CB 1 antagonist AM251, which did not affect URB597-induced social withdrawal, exacerbated OMDM-2 effect. In addition, the potent CB 1 agonist CP55,940 reversed OMDM-2-, but not URB597-, induced social withdrawal. Blockade of CB 1 receptor by AM251 reduced social interaction and the cholecystokinin CCK2 antagonist LY225910 reversed this effect. Similarly, OMDM-2-induced social withdrawal was reversed by LY225910, whereas URB597 effect was not. Elevation of endocannabinoid levels by URB597 or JZL184, an inhibitor of 2-AG degradation, failed to reverse OMDM-2-induced social withdrawal, and did not show additive effects on cannabinoid measurements when co-administered with OMDM-2. Taken together, these findings indicate that OMDM-2 impaired social interaction in a manner that is consistent with reduced activation of presynaptic CB 1 receptors. As cannabinoid reuptake inhibitors may impair endocannabinoid release, caution should be taken when using these drugs to enhance endocannabinoid tone in vivo. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. The irreversible ERBB1/2/4 inhibitor neratinib interacts with the PARP1 inhibitor niraparib to kill ovarian cancer cells.

    Science.gov (United States)

    Booth, Laurence; Roberts, Jane L; Samuel, Peter; Avogadri-Connors, Francesca; Cutler, Richard E; Lalani, Alshad S; Poklepovic, Andrew; Dent, Paul

    2018-06-03

    The irreversible ERBB1/2/4 inhibitor neratinib has been shown to rapidly down-regulate the expression of ERBB1/2/4 as well as the levels of c-MET, PDGFRα and mutant RAS proteins via autophagic degradation. Neratinib interacted in an additive to synergistic fashion with the approved PARP1 inhibitor niraparib to kill ovarian cancer cells. Neratinib and niraparib caused the ATM-dependent activation of AMPK which in turn was required to cause mTOR inactivation, ULK-1 activation and ATG13 phosphorylation. The drug combination initially increased autophagosome levels followed later by autolysosome levels. Preventing autophagosome formation by expressing activated mTOR or knocking down of Beclin1, or knock down of the autolysosome protein cathepsin B, reduced drug combination lethality. The drug combination caused an endoplasmic reticulum stress response as judged by enhanced eIF2α phosphorylation that was responsible for reducing MCL-1 and BCL-XL levels and increasing ATG5 and Beclin1 expression. Knock down of BIM, but not of BAX or BAK, reduced cell killing. Expression of activated MEK1 prevented the drug combination increasing BIM expression and reduced cell killing. Downstream of the mitochondrion, drug lethality was partially reduced by knock down of AIF, but expression of dominant negative caspase 9 was not protective. Our data demonstrate that neratinib and niraparib interact to kill ovarian cancer cells through convergent DNA damage and endoplasmic reticulum stress signaling. Cell killing required the induction of autophagy and was cathepsin B and AIF -dependent, and effector caspase independent.

  16. Insight into interaction mechanism of the inhibitor pDI5W with MDM2 based on molecular dynamics

    International Nuclear Information System (INIS)

    Chen Jianzhong; Liang Zhiqiang; Wang Wei; Liu Jinqing; Zhang Qinggang; Liu Xiaoyang

    2012-01-01

    The p53-MDM2 interaction has been an important target of drug design curing cancers. In this work, molecular dynamics (MD) simulation coupled with molecular mechanics/Poisson Boltzmann surface area method (MM-PBSA) was performed to calculate the binding free energy of peptide inhibitor pDI6W to MDM2. The results show that van der Waals energy is the dominant factor of the pDI6W— MDM2 interaction. Cross-correlation matrix calculated suggests that the main motion of the residues in MMDM2 induced by the inhibitor binding is anti-correlation motion. The calculations of residue-residue interactions between pDI6W and MDM2 not only prove that five residues Phe19', Trp22', Trp23', Leu26' and Thr27' from pDI6W can produce strong interaction with MDM2, but also show that CH-π, CH-CH and π-π interactions drive the binding of pDI6W in the hydrophobic cleft of MDM2. This study can provide theoretical helps for anti-cancer drug designs. (authors)

  17. Small molecule inhibitors uncover synthetic genetic interactions of human flap endonuclease 1 (FEN1 with DNA damage response genes.

    Directory of Open Access Journals (Sweden)

    Thomas A Ward

    Full Text Available Flap endonuclease 1 (FEN1 is a structure selective endonuclease required for proficient DNA replication and the repair of DNA damage. Cellularly active inhibitors of this enzyme have previously been shown to induce a DNA damage response and, ultimately, cell death. High-throughput screens of human cancer cell-lines identify colorectal and gastric cell-lines with microsatellite instability (MSI as enriched for cellular sensitivity to N-hydroxyurea series inhibitors of FEN1, but not the PARP inhibitor olaparib or other inhibitors of the DNA damage response. This sensitivity is due to a synthetic lethal interaction between FEN1 and MRE11A, which is often mutated in MSI cancers through instabilities at a poly(T microsatellite repeat. Disruption of ATM is similarly synthetic lethal with FEN1 inhibition, suggesting that disruption of FEN1 function leads to the accumulation of DNA double-strand breaks. These are likely a result of the accumulation of aberrant replication forks, that accumulate as a consequence of a failure in Okazaki fragment maturation, as inhibition of FEN1 is toxic in cells disrupted for the Fanconi anemia pathway and post-replication repair. Furthermore, RAD51 foci accumulate as a consequence of FEN1 inhibition and the toxicity of FEN1 inhibitors increases in cells disrupted for the homologous recombination pathway, suggesting a role for homologous recombination in the resolution of damage induced by FEN1 inhibition. Finally, FEN1 appears to be required for the repair of damage induced by olaparib and cisplatin within the Fanconi anemia pathway, and may play a role in the repair of damage associated with its own disruption.

  18. The irreversible ERBB1/2/4 inhibitor neratinib interacts with the BCL-2 inhibitor venetoclax to kill mammary cancer cells.

    Science.gov (United States)

    Booth, Laurence; Roberts, Jane L; Avogadri-Connors, Francesca; Cutler, Richard E; Lalani, Alshad S; Poklepovic, Andrew; Dent, Paul

    2018-03-04

    The irreversible ERBB1/2/4 inhibitor, neratinib, down-regulates the expression of ERBB1/2/4 as well as the levels of MCL-1 and BCL-XL. Venetoclax (ABT199) is a BCL-2 inhibitor. At physiologic concentrations neratinib interacted in a synergistic fashion with venetoclax to kill HER2 + and TNBC mammary carcinoma cells. This was associated with the drug-combination: reducing the expression and phosphorylation of ERBB1/2/3; in an eIF2α-dependent fashion reducing the expression of MCL-1 and BCL-XL and increasing the expression of Beclin1 and ATG5; and increasing the activity of the ATM-AMPKα-ULK1 S317 pathway which was causal in the formation of toxic autophagosomes. Although knock down of BAX or BAK reduced drug combination lethality, knock down of BAX and BAK did not prevent the drug combination from increasing autophagosome and autolysosome formation. Knock down of ATM, AMPKα, Beclin1 or over-expression of activated mTOR prevented the induction of autophagy and in parallel suppressed tumor cell killing. Knock down of ATM, AMPKα, Beclin1 or cathepsin B prevented the drug-induced activation of BAX and BAK whereas knock down of BID was only partially inhibitory. A 3-day transient exposure of established estrogen-independent HER2 + BT474 mammary tumors to neratinib or venetoclax did not significantly alter tumor growth whereas exposure to [neratinib + venetoclax] caused a significant 7-day suppression of growth by day 19. The drug combination neither altered animal body mass nor behavior. We conclude that venetoclax enhances neratinib lethality by facilitating toxic BH3 domain protein activation via autophagy which enhances the efficacy of neratinib to promote greater levels of cell killing.

  19. Isothermal Titration Calorimetry and Macromolecular Visualization for the Interaction of Lysozyme and Its Inhibitors

    Science.gov (United States)

    Wei, Chin-Chuan; Jensen, Drake; Boyle, Tiffany; O'Brien, Leah C.; De Meo, Cristina; Shabestary, Nahid; Eder, Douglas J.

    2015-01-01

    To provide a research-like experience to upper-division undergraduate students in a biochemistry teaching laboratory, isothermal titration calorimetry (ITC) is employed to determine the binding constants of lysozyme and its inhibitors, N-acetyl glucosamine trimer (NAG[subscript 3]) and monomer (NAG). The extremely weak binding of lysozyme/NAG is…

  20. The interaction of quaternary reversible acetylcholinesterase inhibitors with the nicotinic receptor

    Czech Academy of Sciences Publication Activity Database

    Šepsová, V.; Krůšek, Jan; Zdarová Karasová, J.; Zemek, F.; Musílek, K.; Kuča, K.; Soukup, O.

    2014-01-01

    Roč. 63, č. 6 (2014), s. 771-777 ISSN 0862-8408 R&D Projects: GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 Keywords : acetylcholinesterase inhibitor * nicotin receptor Subject RIV: ED - Physiology Impact factor: 1.293, year: 2014

  1. Effect of endocytosis inhibitors on Coxiella burnetii interaction with host cells

    International Nuclear Information System (INIS)

    Tujulin, E.; Macellaro, A.; Norlander, L.; Liliehoeoek, B.

    1998-01-01

    The obligate intracellular rickettsia Coxiella burnetii has previously been reported to reach the intra-vacuolar compartment of host cells by phagocytosis. With the aim to further examine the mechanisms of C. burnetii internalisation, macrophage monolayers were treated with well characterised inhibitors of endocytosis. The treatment with two general inhibitors, colchicine and methylamine, resulted in a pronounced dose-dependent decrease of radiolabelled phase II rickettsiae retained from the intracellular fraction. A third inhibitor used, amiloride, has been reported to reduce effectively clathrin-independent pinocytic pathways. The internalisation of C. burnetii was shown to be substantially reduced also by amiloride and the effect was dependent on its concentration. The passive role of C. burnetii in the internalisation was verified by using heat-killed C. burnetii. Host cells treated with either of the three inhibitors (amiloride, colchicine and methylamine) showed a similar reduction of intracellular C. burnetii after exposure to killed as weal as live organisms. The data presented indicate that different endocytic mechanisms, pinocytosis as well as phagocytosis, may mediate the uptake of C. burnetii by a host cell. Key words: Coxiella burnetii; internalisation; endocytosis (authors)

  2. 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....

  3. Computational analysis of calculated physicochemical and ADMET properties of protein-protein interaction inhibitors

    Science.gov (United States)

    Lagorce, David; Douguet, Dominique; Miteva, Maria A.; Villoutreix, Bruno O.

    2017-04-01

    The modulation of PPIs by low molecular weight chemical compounds, particularly by orally bioavailable molecules, would be very valuable in numerous disease indications. However, it is known that PPI inhibitors (iPPIs) tend to have properties that are linked to poor Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) and in some cases to poor clinical outcomes. Previously reported in silico analyses of iPPIs have essentially focused on physicochemical properties but several other ADMET parameters would be important to assess. In order to gain new insights into the ADMET properties of iPPIs, computations were carried out on eight datasets collected from several databases. These datasets involve compounds targeting enzymes, GPCRs, ion channels, nuclear receptors, allosteric modulators, oral marketed drugs, oral natural product-derived marketed drugs and iPPIs. Several trends are reported that should assist the design and optimization of future PPI inhibitors, either for drug discovery endeavors or for chemical biology projects.

  4. Sibiriline, a new small chemical inhibitor of receptor-interacting protein kinase 1, prevents immune-dependent hepatitis.

    Science.gov (United States)

    Le Cann, Fabienne; Delehouzé, Claire; Leverrier-Penna, Sabrina; Filliol, Aveline; Comte, Arnaud; Delalande, Olivier; Desban, Nathalie; Baratte, Blandine; Gallais, Isabelle; Piquet-Pellorce, Claire; Faurez, Florence; Bonnet, Marion; Mettey, Yvette; Goekjian, Peter; Samson, Michel; Vandenabeele, Peter; Bach, Stéphane; Dimanche-Boitrel, Marie-Thérèse

    2017-09-01

    Necroptosis is a regulated form of cell death involved in several disease models including in particular liver diseases. Receptor-interacting protein kinases, RIPK1 and RIPK3, are the main serine/threonine kinases driving this cell death pathway. We screened a noncommercial, kinase-focused chemical library which allowed us to identify Sibiriline as a new inhibitor of necroptosis induced by tumor necrosis factor (TNF) in Fas-associated protein with death domain (FADD)-deficient Jurkat cells. Moreover, Sib inhibits necroptotic cell death induced by various death ligands in human or mouse cells while not protecting from caspase-dependent apoptosis. By using competition binding assay and recombinant kinase assays, we demonstrated that Sib is a rather specific competitive RIPK1 inhibitor. Molecular docking analysis shows that Sib is trapped closed to human RIPK1 adenosine triphosphate-binding site in a relatively hydrophobic pocket locking RIPK1 in an inactive conformation. In agreement with its RIPK1 inhibitory property, Sib inhibits both TNF-induced RIPK1-dependent necroptosis and RIPK1-dependent apoptosis. Finally, Sib protects mice from concanavalin A-induced hepatitis. These results reveal the small-molecule Sib as a new RIPK1 inhibitor potentially of interest for the treatment of immune-dependent hepatitis. © 2017 Federation of European Biochemical Societies.

  5. Novel Inhibitors of Protein-Protein Interaction for Prostate Cancer Therapy

    Science.gov (United States)

    2014-04-01

    treated mice compared to vehicle control. A subset of mice was followed by longitudinal MRI imaging for prostate tumor growth. As shown in Figure...treated (N=7) mice were followed by longitudinal MRI imaging for tumor growth (bottom panel). 9 KEY RESEARCH ACCOMPLISHMENTS • Identified...EDTA) containing a tablet of complete protease inhibitors from Roche (Indianapolis, IN). Total protein from each sample was separated on a 4–12% Bis

  6. Glycosaminoglycans affect the interaction of human plasma kallikrein with plasminogen, factor XII and inhibitors

    Directory of Open Access Journals (Sweden)

    Gozzo A.J.

    2003-01-01

    Full Text Available Human plasma kallikrein, a serine proteinase, plays a key role in intrinsic blood clotting, in the kallikrein-kinin system, and in fibrinolysis. The proteolytic enzymes involved in these processes are usually controlled by specific inhibitors and may be influenced by several factors including glycosaminoglycans, as recently demonstrated by our group. The aim of the present study was to investigate the effect of glycosaminoglycans (30 to 250 µg/ml on kallikrein activity on plasminogen and factor XII and on the inhibition of kallikrein by the plasma proteins C1-inhibitor and antithrombin. Almost all available glycosaminoglycans (heparin, heparan sulfate, bovine and tuna dermatan sulfate, chondroitin 4- and 6-sulfates reduced (1.2 to 3.0 times the catalytic efficiency of kallikrein (in a nanomolar range on the hydrolysis of plasminogen (0.3 to 1.8 µM and increased (1.9 to 7.7 times the enzyme efficiency in factor XII (0.1 to 10 µM activation. On the other hand, heparin, heparan sulfate, and bovine and tuna dermatan sulfate improved (1.2 to 3.4 times kallikrein inhibition by antithrombin (1.4 µM, while chondroitin 4- and 6-sulfates reduced it (1.3 times. Heparin and heparan sulfate increased (1.4 times the enzyme inhibition by the C1-inhibitor (150 nM.

  7. Small molecule inhibitors of ERCC1-XPF protein-protein interaction synergize alkylating agents in cancer cells.

    Science.gov (United States)

    Jordheim, Lars Petter; Barakat, Khaled H; Heinrich-Balard, Laurence; Matera, Eva-Laure; Cros-Perrial, Emeline; Bouledrak, Karima; El Sabeh, Rana; Perez-Pineiro, Rolando; Wishart, David S; Cohen, Richard; Tuszynski, Jack; Dumontet, Charles

    2013-07-01

    The benefit of cancer chemotherapy based on alkylating agents is limited because of the action of DNA repair enzymes, which mitigate the damage induced by these agents. The interaction between the proteins ERCC1 and XPF involves two major components of the nucleotide excision repair pathway. Here, novel inhibitors of this interaction were identified by virtual screening based on available structures with use of the National Cancer Institute diversity set and a panel of DrugBank small molecules. Subsequently, experimental validation of the in silico screening was undertaken. Top hits were evaluated on A549 and HCT116 cancer cells. In particular, the compound labeled NSC 130813 [4-[(6-chloro-2-methoxy-9-acridinyl)amino]-2-[(4-methyl-1-piperazinyl)methyl

  8. Inhibitor of CDK interacting with cyclin A1 (INCA1) regulates proliferation and is repressed by oncogenic signaling

    DEFF Research Database (Denmark)

    Baumer, Nicole; Tickenbrock, Lara; Tschanter, Petra

    2011-01-01

    The cell cycle is driven by the kinase activity of cyclin/CDK complexes which is negatively regulated by CDK inhibitor proteins. Recently, we identified INCA1 as interaction partner and substrate of cyclin A1 in complex with CDK2. On a functional level, we identified a novel cyclin binding site...... in the INCA1 protein. INCA1 inhibited CDK2 activity and cell proliferation. The inihibitory effects depended on the cyclin-interacting domain. Mitogenic and oncogenic signals suppressed INCA1 expression, while it was induced by cell cycle arrest. We established a deletional mouse model that showed increased...... CDK2 activity in spleen with altered spleen architecture in Inca1-/- mice. Inca1-/- embryonic fibroblasts showed an increase in the fraction of S-phase cells. Furthermore, blasts from ALL and AML patients expressed significantly reduced INCA1 levels highlighting its relevance for growth control...

  9. 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.

  10. Effective screening strategy using ensembled pharmacophore models combined with cascade docking: application to p53-MDM2 interaction inhibitors.

    Science.gov (United States)

    Xue, Xin; Wei, Jin-Lian; Xu, Li-Li; Xi, Mei-Yang; Xu, Xiao-Li; Liu, Fang; Guo, Xiao-Ke; Wang, Lei; Zhang, Xiao-Jin; Zhang, Ming-Ye; Lu, Meng-Chen; Sun, Hao-Peng; You, Qi-Dong

    2013-10-28

    Protein-protein interactions (PPIs) play a crucial role in cellular function and form the backbone of almost all biochemical processes. In recent years, protein-protein interaction inhibitors (PPIIs) have represented a treasure trove of potential new drug targets. Unfortunately, there are few successful drugs of PPIIs on the market. Structure-based pharmacophore (SBP) combined with docking has been demonstrated as a useful Virtual Screening (VS) strategy in drug development projects. However, the combination of target complexity and poor binding affinity prediction has thwarted the application of this strategy in the discovery of PPIIs. Here we report an effective VS strategy on p53-MDM2 PPI. First, we built a SBP model based on p53-MDM2 complex cocrystal structures. The model was then simplified by using a Receptor-Ligand complex-based pharmacophore model considering the critical binding features between MDM2 and its small molecular inhibitors. Cascade docking was subsequently applied to improve the hit rate. Based on this strategy, we performed VS on NCI and SPECS databases and successfully discovered 6 novel compounds from 15 hits with the best, compound 1 (NSC 5359), K(i) = 180 ± 50 nM. These compounds can serve as lead compounds for further optimization.

  11. Design, Synthesis and Evaluation of 2,5-Diketopiperazines as Inhibitors of the MDM2-p53 Interaction.

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    Mariell Pettersson

    Full Text Available The transcription factor p53 is the main tumour suppressor in cells and many cancer types have p53 mutations resulting in a loss of its function. In tumours that retain wild-type p53 function, p53 activity is down-regulated by MDM2 (human murine double minute 2 via a direct protein-protein interaction. We have designed and synthesised two series of 2,5-diketopiperazines as inhibitors of the MDM2-p53 interaction. The first set was designed to directly mimic the α-helical region of the p53 peptide, containing key residues in the i, i+4 and i+7 positions of a natural α-helix. Conformational analysis indicated that 1,3,6-trisubstituted 2,5-diketopiperazines were able to place substituents in the same spatial orientation as an α-helix template. The key step of the synthesis involved the cyclisation of substituted dipeptides. The other set of tetrasubstituted 2,5-diketopiperazines were designed based on structure-based docking studies and the Ugi multicomponent reaction was used for the synthesis. This latter set comprised the most potent inhibitors which displayed micromolar IC50-values in a biochemical fluorescence polarisation assay.

  12. 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.

  13. Macrocyclic peptide inhibitors for the protein-protein interaction of Zaire Ebola virus protein 24 and karyopherin alpha 5.

    Science.gov (United States)

    Song, Xiao; Lu, Lu-Yi; Passioura, Toby; Suga, Hiroaki

    2017-06-21

    Ebola virus infection leads to severe hemorrhagic fever in human and non-human primates with an average case fatality rate of 50%. To date, numerous potential therapies are in development, but FDA-approved drugs or vaccines are yet unavailable. Ebola viral protein 24 (VP24) is a multifunctional protein that plays critical roles in the pathogenesis of Ebola virus infection, e.g. innate immune suppression by blocking the interaction between KPNA and PY-STAT1. Here we report macrocyclic peptide inhibitors of the VP24-KPNA5 protein-protein interaction (PPI) by means of the RaPID (Random non-standard Peptides Integrated Discovery) system. These macrocyclic peptides showed remarkably high affinity to recombinant Zaire Ebola virus VP24 (eVP24), with a dissociation constant in the single digit nanomolar range, and could also successfully disrupt the eVP24-KPNA interaction. This work provides for the first time a chemical probe capable of modulating this PPI interaction and is the starting point for the development of unique anti-viral drugs against the Ebola virus.

  14. Computational Analysis of Molecular Interaction Networks Underlying Change of HIV-1 Resistance to Selected Reverse Transcriptase Inhibitors.

    Science.gov (United States)

    Kierczak, Marcin; Dramiński, Michał; Koronacki, Jacek; Komorowski, Jan

    2010-12-12

    Despite more than two decades of research, HIV resistance to drugs remains a serious obstacle in developing efficient AIDS treatments. Several computational methods have been developed to predict resistance level from the sequence of viral proteins such as reverse transcriptase (RT) or protease. These methods, while powerful and accurate, give very little insight into the molecular interactions that underly acquisition of drug resistance/hypersusceptibility. Here, we attempt at filling this gap by using our Monte Carlo feature selection and interdependency discovery method (MCFS-ID) to elucidate molecular interaction networks that characterize viral strains with altered drug resistance levels. We analyzed a number of HIV-1 RT sequences annotated with drug resistance level using the MCFS-ID method. This let us expound interdependency networks that characterize change of drug resistance to six selected RT inhibitors: Abacavir, Lamivudine, Stavudine, Zidovudine, Tenofovir and Nevirapine. The networks consider interdependencies at the level of physicochemical properties of mutating amino acids, eg,: polarity. We mapped each network on the 3D structure of RT in attempt to understand the molecular meaning of interacting pairs. The discovered interactions describe several known drug resistance mechanisms and, importantly, some previously unidentified ones. Our approach can be easily applied to a whole range of problems from the domain of protein engineering. A portable Java implementation of our MCFS-ID method is freely available for academic users and can be obtained at: http://www.ipipan.eu/staff/m.draminski/software.htm.

  15. Cardiovascular Side Effects of Atomoxetine and Its Interactions with Inhibitors of the Cytochrome P450 System

    Directory of Open Access Journals (Sweden)

    Pashtoon Murtaza Kasi

    2011-01-01

    Full Text Available Attention deficit hyperactivity disorder (ADHD is one of the most common neurobehavioral disorders of childhood and adolescence. Classically, stimulants have been used in the treatment of this condition. Atomoxetine (Strattera; Eli Lilly and Company is a selective norepinephrine reuptake inhibitor (SNRI, one of the first medications in the nonstimulant class of medications that has been approved by the FDA for the treatment of ADHD. Atomoxetine is a phenoxypropylamine derivative and is structurally related to the antidepressant fluoxetine. The common side effects reported with the use of atomoxetine include mainly GI disturbances. Cardiovascular side effects are less commonly reported. The increase in the noradrenergic tone may explain some of the side effects noted with the use of this medication. Here, we present a case of a patient who presented with syncope, orthostatic hypotension, and tachycardia and discuss the various clinical implications based on the pharmacokinetics and pharmacodynamics of the drug.

  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. Interaction of Zinc Chloride with an Aromatase Inhibitor (Letrozole on Anxiety in Adult Male Rats

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    Sahar Charghan

    2016-12-01

    Full Text Available Abstract Background: Aromatase is an enzyme converts androstenedione and testosterone to estrone and estradiol, respectively. According to the role of testosterone and zinc in reducing anxiety and the relation between androgenic system function and zinc supplementations, in this research, the effect of zinc chloride injection was analysed in rats which aromatase enzyme was inhibited by aromatase inhibitor (letrozole. Materials and Methods: Adult male Wistar rats (weighing 225±25 g were used. Animals were divided into 12 groups and based on their weight, aromatase inhibitor (letrozole was injected (subcutaneously, and 30 minutes later, ZnCl2 or its solvent (saline was injected intra-peritoneal. Control group was received both solvents (DMSO and saline respectively. Anxiety levels were tested in the elevated plus maze 30 minutes after the last injection, and thereafter, open field was used for measurement of the locomotors activity of animals. Results: The results showed a significant decrease in the percentage of time spent in open arms in letrozole (1.25 mg/kg treated group as compared to that of solvent group. The locomotors activity significantly decreased between letrozole (1.25 mg/kg with the control group. The combined groups received letrozole (2.5 mg/kg and different amounts of zinc chloride (2.5, 5, 10 mg/kg, significantly reduced (p<0.05 the percentage of time spent in the open arm, comparing to the control group. Groups that received the combination of zinc chloride (2.5 mg/kg and different amounts of letrozole (1.25, 5, 10 mg/kg, showed no significant difference in the percentage of entry and time spent in the open arms. Conclusion: Totally, the present study suggests that letrozole alone increased anxiety and decreased locomotors activity and could interfere with anxiolytic effect of ZnCl2 as well.

  18. Electrostatic similarities between protein and small molecule ligands facilitate the design of protein-protein interaction inhibitors.

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    Arnout Voet

    Full Text Available One of the underlying principles in drug discovery is that a biologically active compound is complimentary in shape and molecular recognition features to its receptor. This principle infers that molecules binding to the same receptor may share some common features. Here, we have investigated whether the electrostatic similarity can be used for the discovery of small molecule protein-protein interaction inhibitors (SMPPIIs. We have developed a method that can be used to evaluate the similarity of electrostatic potentials between small molecules and known protein ligands. This method was implemented in a software called EleKit. Analyses of all available (at the time of research SMPPII structures indicate that SMPPIIs bear some similarities of electrostatic potential with the ligand proteins of the same receptor. This is especially true for the more polar SMPPIIs. Retrospective analysis of several successful SMPPIIs has shown the applicability of EleKit in the design of new SMPPIIs.

  19. Molecular Determinants Underlying Binding Specificities of the ABL Kinase Inhibitors: Combining Alanine Scanning of Binding Hot Spots with Network Analysis of Residue Interactions and Coevolution.

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    Amanda Tse

    Full Text Available Quantifying binding specificity and drug resistance of protein kinase inhibitors is of fundamental importance and remains highly challenging due to complex interplay of structural and thermodynamic factors. In this work, molecular simulations and computational alanine scanning are combined with the network-based approaches to characterize molecular determinants underlying binding specificities of the ABL kinase inhibitors. The proposed theoretical framework unveiled a relationship between ligand binding and inhibitor-mediated changes in the residue interaction networks. By using topological parameters, we have described the organization of the residue interaction networks and networks of coevolving residues in the ABL kinase structures. This analysis has shown that functionally critical regulatory residues can simultaneously embody strong coevolutionary signal and high network centrality with a propensity to be energetic hot spots for drug binding. We have found that selective (Nilotinib and promiscuous (Bosutinib, Dasatinib kinase inhibitors can use their energetic hot spots to differentially modulate stability of the residue interaction networks, thus inhibiting or promoting conformational equilibrium between inactive and active states. According to our results, Nilotinib binding may induce a significant network-bridging effect and enhance centrality of the hot spot residues that stabilize structural environment favored by the specific kinase form. In contrast, Bosutinib and Dasatinib can incur modest changes in the residue interaction network in which ligand binding is primarily coupled only with the identity of the gate-keeper residue. These factors may promote structural adaptability of the active kinase states in binding with these promiscuous inhibitors. Our results have related ligand-induced changes in the residue interaction networks with drug resistance effects, showing that network robustness may be compromised by targeted mutations

  20. Molecular Determinants Underlying Binding Specificities of the ABL Kinase Inhibitors: Combining Alanine Scanning of Binding Hot Spots with Network Analysis of Residue Interactions and Coevolution

    Science.gov (United States)

    Tse, Amanda; Verkhivker, Gennady M.

    2015-01-01

    Quantifying binding specificity and drug resistance of protein kinase inhibitors is of fundamental importance and remains highly challenging due to complex interplay of structural and thermodynamic factors. In this work, molecular simulations and computational alanine scanning are combined with the network-based approaches to characterize molecular determinants underlying binding specificities of the ABL kinase inhibitors. The proposed theoretical framework unveiled a relationship between ligand binding and inhibitor-mediated changes in the residue interaction networks. By using topological parameters, we have described the organization of the residue interaction networks and networks of coevolving residues in the ABL kinase structures. This analysis has shown that functionally critical regulatory residues can simultaneously embody strong coevolutionary signal and high network centrality with a propensity to be energetic hot spots for drug binding. We have found that selective (Nilotinib) and promiscuous (Bosutinib, Dasatinib) kinase inhibitors can use their energetic hot spots to differentially modulate stability of the residue interaction networks, thus inhibiting or promoting conformational equilibrium between inactive and active states. According to our results, Nilotinib binding may induce a significant network-bridging effect and enhance centrality of the hot spot residues that stabilize structural environment favored by the specific kinase form. In contrast, Bosutinib and Dasatinib can incur modest changes in the residue interaction network in which ligand binding is primarily coupled only with the identity of the gate-keeper residue. These factors may promote structural adaptability of the active kinase states in binding with these promiscuous inhibitors. Our results have related ligand-induced changes in the residue interaction networks with drug resistance effects, showing that network robustness may be compromised by targeted mutations of key mediating

  1. LHX3 interacts with inhibitor of histone acetyltransferase complex subunits LANP and TAF-1β to modulate pituitary gene regulation.

    Science.gov (United States)

    Hunter, Chad S; Malik, Raleigh E; Witzmann, Frank A; Rhodes, Simon J

    2013-01-01

    LIM-homeodomain 3 (LHX3) is a transcription factor required for mammalian pituitary gland and nervous system development. Human patients and animal models with LHX3 gene mutations present with severe pediatric syndromes that feature hormone deficiencies and symptoms associated with nervous system dysfunction. The carboxyl terminus of the LHX3 protein is required for pituitary gene regulation, but the mechanism by which this domain operates is unknown. In order to better understand LHX3-dependent pituitary hormone gene transcription, we used biochemical and mass spectrometry approaches to identify and characterize proteins that interact with the LHX3 carboxyl terminus. This approach identified the LANP/pp32 and TAF-1β/SET proteins, which are components of the inhibitor of histone acetyltransferase (INHAT) multi-subunit complex that serves as a multifunctional repressor to inhibit histone acetylation and modulate chromatin structure. The protein domains of LANP and TAF-1β that interact with LHX3 were mapped using biochemical techniques. Chromatin immunoprecipitation experiments demonstrated that LANP and TAF-1β are associated with LHX3 target genes in pituitary cells, and experimental alterations of LANP and TAF-1β levels affected LHX3-mediated pituitary gene regulation. Together, these data suggest that transcriptional regulation of pituitary genes by LHX3 involves regulated interactions with the INHAT complex.

  2. Multi-spectroscopic and molecular docking studies on the interaction of darunavir, a HIV protease inhibitor with calf thymus DNA.

    Science.gov (United States)

    Shi, Jie-Hua; Zhou, Kai-Li; Lou, Yan-Yue; Pan, Dong-Qi

    2018-03-15

    Molecular interaction of darunavir (DRV), a HIV protease inhibitor with calf thymus deoxyribonucleic acid (ct-DNA) was studied in physiological buffer (pH7.4) by multi-spectroscopic approaches hand in hand with viscosity measurements and molecular docking technique. The UV absorption and fluorescence results together revealed the formation of a DRV-ct-DNA complex having binding affinities of the order of 10 3 M -1 , which was more in keeping with the groove binding. The results that DRV bound to ct-DNA via groove binding mode was further evidenced by KI quenching studies, viscosity measurements, competitive binding investigations with EB and Rhodamine B and CD spectral analysis. The effect of ionic strength indicated the negligible involvement of electrostatic interaction between DRV and ct-DNA. The thermodynamic parameters regarding the binding interaction of DRV with ct-DNA in terms of enthalpy change (ΔH 0 ) and entropy change (ΔS 0 ) were -63.19kJ mol -1 and -141.92J mol -1 K -1 , indicating that hydrogen bonds and van der Waals forces played a predominant role in the binding process. Furthermore, molecular simulation studies suggested that DRV molecule was prone to bind in the A-T rich region of the minor groove of DNA. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Drug–drug interaction of microdose and regular-dose omeprazole with a CYP2C19 inhibitor and inducer

    Science.gov (United States)

    Park, Gab-jin; Bae, Soo Hyeon; Park, Wan-Su; Han, Seunghoon; Park, Min-Ho; Shin, Seok-Ho; Shin, Young G; Yim, Dong-Seok

    2017-01-01

    Purpose A microdose drug–drug interaction (DDI) study may be a valuable tool for anticipating drug interaction at therapeutic doses. This study aimed to compare the magnitude of DDIs at microdoses and regular doses to explore the applicability of a microdose DDI study. Patients and methods Six healthy male volunteer subjects were enrolled into each DDI study of omeprazole (victim) and known perpetrators: fluconazole (inhibitor) and rifampin (inducer). For both studies, the microdose (100 μg, cold compound) and the regular dose (20 mg) of omeprazole were given at days 0 and 1, respectively. On days 2–9, the inhibitor or inducer was given daily, and the microdose and regular dose of omeprazole were repeated at days 8 and 9, respectively. Full omeprazole pharmacokinetic samplings were performed at days 0, 1, 8, and 9 of both studies for noncompartmental analysis. Results The magnitude of the DDI, the geometric mean ratios (with perpetrator/omeprazole only) of maximum concentration (Cmax) and area under the curve to the last measurement (AUCt) of the microdose and the regular dose were compared. The geometric mean ratios in the inhibition study were: 2.17 (micro) and 2.68 (regular) for Cmax, and 4.07 (micro), 4.33 (regular) for AUCt. For the induction study, they were 0.26 (micro) and 0.21 (regular) for Cmax, and 0.16 (micro) and 0.15 (regular) for AUCt. There were no significant statistical differences in the magnitudes of DDIs between microdose and regular-dose conditions, regardless of induction or inhibition. Conclusion Our results may be used as partial evidence that microdose DDI studies may replace regular-dose studies, or at least be used for DDI-screening purposes. PMID:28408803

  4. Drug-drug interaction of microdose and regular-dose omeprazole with a CYP2C19 inhibitor and inducer.

    Science.gov (United States)

    Park, Gab-Jin; Bae, Soo Hyeon; Park, Wan-Su; Han, Seunghoon; Park, Min-Ho; Shin, Seok-Ho; Shin, Young G; Yim, Dong-Seok

    2017-01-01

    A microdose drug-drug interaction (DDI) study may be a valuable tool for anticipating drug interaction at therapeutic doses. This study aimed to compare the magnitude of DDIs at microdoses and regular doses to explore the applicability of a microdose DDI study. Six healthy male volunteer subjects were enrolled into each DDI study of omeprazole (victim) and known perpetrators: fluconazole (inhibitor) and rifampin (inducer). For both studies, the microdose (100 μg, cold compound) and the regular dose (20 mg) of omeprazole were given at days 0 and 1, respectively. On days 2-9, the inhibitor or inducer was given daily, and the microdose and regular dose of omeprazole were repeated at days 8 and 9, respectively. Full omeprazole pharmacokinetic samplings were performed at days 0, 1, 8, and 9 of both studies for noncompartmental analysis. The magnitude of the DDI, the geometric mean ratios (with perpetrator/omeprazole only) of maximum concentration (C max ) and area under the curve to the last measurement (AUC t ) of the microdose and the regular dose were compared. The geometric mean ratios in the inhibition study were: 2.17 (micro) and 2.68 (regular) for C max , and 4.07 (micro), 4.33 (regular) for AUC t . For the induction study, they were 0.26 (micro) and 0.21 (regular) for C max , and 0.16 (micro) and 0.15 (regular) for AUC t . There were no significant statistical differences in the magnitudes of DDIs between microdose and regular-dose conditions, regardless of induction or inhibition. Our results may be used as partial evidence that microdose DDI studies may replace regular-dose studies, or at least be used for DDI-screening purposes.

  5. Pharmacological interaction between oxcarbazepine and two COX inhibitors in a rat model of inflammatory hyperalgesia.

    Science.gov (United States)

    Stepanović-Petrović, Radica M; Tomić, Maja A; Vučković, Sonja M; Poznanović, Goran; Ugrešić, Nenad D; Prostran, Milica Š; Bošković, Bogdan

    2011-01-01

    Oxcarbazepine, ibuprofen and etodolac have efficacy in inflammatory pain. The combination of different drugs activates both central and peripheral pain inhibitory pathways to induce additive or synergistic antinociception, and this interaction may allow lower doses of each drug combined and improve the safety profile, with lower side-effects. This study aimed to examine the effects of oxcarbazepine-ibuprofen and oxcarbazepine-etodolac combinations, in a rat model of inflammatory hyperalgesia, and determine the type of interaction between drugs. Rats were intraplantarly injected with carrageenan (0.1 ml, 1%) and the hyperalgesia was assessed by modified paw pressure test. The anti-hyperalgesic effects of oxcarbazepine, ibuprofen and etodolac and oxcarbazepine-ibuprofen and oxcarbazepine-etodolac combinations were examined. Drugs were co-administered in a fixed-dose fractions of the ED₅₀ and the type of interaction was determined by isobolographic analysis. Oxcarbazepine (40-160 mg/kg; p.o.), ibuprofen (10-120 mg/kg; p.o.) and etodolac (5-20 mg/kg; p.o.) produced a significant, dose-dependent anti-hyperalgesia in carrageenan-injected rats. ED₅₀ values (mean±SEM) for oxcarbazepine, ibuprofen and etodolac were 88.17±3.65, 47.07±10.27 and 13.05±1.42 mg/kg, respectively. Oxcarbazepine-ibuprofen and oxcarbazepine-etodolac combinations induced significant and dose-dependent anti-hyperalgesia. Isobolographic analysis revealed that oxcarbazepine exerts a synergistic interaction with ibuprofen, with almost 4-fold reduction of doses of both drugs in combination. In contrast, there was an additive interaction with etodolac. Synergistic interaction of oxcarbazepine with ibuprofen and its additive interaction with etodolac provide new information about the combination pain treatment and could be explored further in patients with inflammatory pain. Adverse effect analysis of the combinations is necessary to verify possible clinical use of the mixtures. Copyright

  6. Inhibitors of SOD1 Interaction as an Approach to Slow the Progressive Spread of ALS Symptoms

    Science.gov (United States)

    2016-07-01

    the progression of ALS caused by mutations in this protein . To accomplish this goal, we developed an assay that is based on the observation that the...force. In our assay , this force is the normal interaction that occurs when 2 individual SOD1 proteins come together to form a normal active enzyme...Using recombinant DNA, we create fusion proteins of SOD1 and each half of the luciferase enzyme. In the past year, we have characterized and optimized

  7. Drug–drug interaction of microdose and regular-dose omeprazole with a CYP2C19 inhibitor and inducer

    Directory of Open Access Journals (Sweden)

    Park G

    2017-03-01

    Full Text Available Gab-jin Park,1 Soo Hyeon Bae,1 Wan-Su Park,1 Seunghoon Han,1 Min-Ho Park,2 Seok-Ho Shin,2 Young G Shin,2 Dong-Seok Yim1,2 1Department of Clinical Pharmacology and Therapeutics, Seoul St Mary’s Hospital, PIPET (Pharmacometrics Institute for Practical Education and Training, College of Medicine, Catholic University of Korea, Seoul, South Korea; 2College of Pharmacy, Chungnam National University, Daejeon, South Korea Purpose: A microdose drug–drug interaction (DDI study may be a valuable tool for anticipating drug interaction at therapeutic doses. This study aimed to compare the magnitude of DDIs at microdoses and regular doses to explore the applicability of a microdose DDI study. Patients and methods: Six healthy male volunteer subjects were enrolled into each DDI study of omeprazole (victim and known perpetrators: fluconazole (inhibitor and rifampin (inducer. For both studies, the microdose (100 µg, cold compound and the regular dose (20 mg of omeprazole were given at days 0 and 1, respectively. On days 2–9, the inhibitor or inducer was given daily, and the microdose and regular dose of omeprazole were repeated at days 8 and 9, respectively. Full omeprazole pharmacokinetic samplings were performed at days 0, 1, 8, and 9 of both studies for noncompartmental analysis. Results: The magnitude of the DDI, the geometric mean ratios (with perpetrator/omeprazole only of maximum concentration (Cmax and area under the curve to the last measurement (AUCt of the microdose and the regular dose were compared. The geometric mean ratios in the inhibition study were: 2.17 (micro and 2.68 (regular for Cmax, and 4.07 (micro, 4.33 (regular for AUCt. For the induction study, they were 0.26 (micro and 0.21 (regular for Cmax, and 0.16 (micro and 0.15 (regular for AUCt. There were no significant statistical differences in the magnitudes of DDIs between microdose and regular-dose conditions, regardless of induction or inhibition. Conclusion: Our results may be

  8. Grb7 SH2 domain structure and interactions with a cyclic peptide inhibitor of cancer cell migration and proliferation

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    Pero Stephanie C

    2007-09-01

    Full Text Available Abstract Background Human growth factor receptor bound protein 7 (Grb7 is an adapter protein that mediates the coupling of tyrosine kinases with their downstream signaling pathways. Grb7 is frequently overexpressed in invasive and metastatic human cancers and is implicated in cancer progression via its interaction with the ErbB2 receptor and focal adhesion kinase (FAK that play critical roles in cell proliferation and migration. It is thus a prime target for the development of novel anti-cancer therapies. Recently, an inhibitory peptide (G7-18NATE has been developed which binds specifically to the Grb7 SH2 domain and is able to attenuate cancer cell proliferation and migration in various cancer cell lines. Results As a first step towards understanding how Grb7 may be inhibited by G7-18NATE, we solved the crystal structure of the Grb7 SH2 domain to 2.1 Å resolution. We describe the details of the peptide binding site underlying target specificity, as well as the dimer interface of Grb 7 SH2. Dimer formation of Grb7 was determined to be in the μM range using analytical ultracentrifugation for both full-length Grb7 and the SH2 domain alone, suggesting the SH2 domain forms the basis of a physiological dimer. ITC measurements of the interaction of the G7-18NATE peptide with the Grb7 SH2 domain revealed that it binds with a binding affinity of Kd = ~35.7 μM and NMR spectroscopy titration experiments revealed that peptide binding causes perturbations to both the ligand binding surface of the Grb7 SH2 domain as well as to the dimer interface, suggesting that dimerisation of Grb7 is impacted on by peptide binding. Conclusion Together the data allow us to propose a model of the Grb7 SH2 domain/G7-18NATE interaction and to rationalize the basis for the observed binding specificity and affinity. We propose that the current study will assist with the development of second generation Grb7 SH2 domain inhibitors, potentially leading to novel inhibitors of

  9. Characterizing the interactions between prolyl isomerase pin1 and phosphatase inhibitor-2 in living cells with FRET and FCS

    Science.gov (United States)

    Sun, Yuansheng; Wang, Lifu; Jyothikumar, Vinod; Brautigan, David L.; Periasamy, Ammasi

    2012-03-01

    Phosphatase inhibitor-2 (I2) was discovered as a regulator of protein Ser/Thr phosphatase-1 and is conserved from yeast to human. Binding between purified recombinant I2 from different species and the prolyl isomerase Pin1 has been demonstrated with pull-down assays, size exclusion chromatography and nuclear magnetic resonance spectroscopy. Despite this, questions persist as to whether these proteins associate together in living cells. In this study, we prepared fluorescent protein (FP) fusions of I2 and Pin1 and employed both Förster Resonance Energy Transfer (FRET) and Fluorescence Correlation Spectroscopy (FCS) imaging techniques to characterize their interactions in living cells. In both intensity-based and time-resolved FRET studies, we observed FRET uniformly across whole cells co-expressing I2-Cerulean and Pin1-Venus that was significantly higher than in negative controls expressing Cerulean FP (without fusing to I2) as the FRET donor and Pin1-Venus, showing a specific interaction between I2-Cerulean and Pin1-Venus in living cells. We also observed the co-diffusion of I2-Cerulean and Pin1-mCherry in Fluorescence Cross Correlation Spectroscopy (FCCS) measurements. We further showed that I2 itself as well as I2-Pin1 formed complexes in living cells (predicted from in vitro studies) via a quantitative FRET assay, and demonstrated from FCS measurements that both I2 and Pin1 (fused to Cerulean) are highly mobile in living cells.

  10. Benazepril, an angiotensin converting enzyme inhibitor: drug interaction with salbutamol and bronchial response to histamine in normal subjects

    Science.gov (United States)

    Bauer, K. G.; Brunel, P.; Nell, G.; Quinn, G.; Kaik, G. A.

    1997-01-01

    Aims To investigate the effect of the angiotensin converting enzyme inhibitor, benazepril, on pulmonary function. Methods We investigated the influence of benazepril, on lung function and the interaction with inhaled salbutamol (0.1 to 6.6 mg) and histamine (0.03 to 30.69 g l−1 ) in normal subjects. Benazepril 20 mg, salbutamol 8 mg, propranolol 160 mg, and placebo were given orally once daily over 10 days. Results On day 8, there was no difference in the area under the salbutamol dose-response curves between benazepril, placebo and oral salbutamol (P >0.05), propranolol shifted the curves to the right (Pbenazepril 1.04 (0.99–1.08), salbutamol 1.19 (1.13–1.25), propranolol 0.57 (0.50–0.65). Conclusions Benazepril had no influence on baseline lung function, caused no interaction with inhaled salbutamol and the bronchial response to histamine was similar to placebo. However, our findings in normal subjects cannot be extrapolated automatically to asthmatics. PMID:9431834

  11. Pharmacovigilance Evaluation of the Association Between DPP-4 Inhibitors and Heart Failure: Stimulated Reporting and Moderation by Drug Interactions.

    Science.gov (United States)

    Fadini, Gian Paolo; Sarangdhar, Mayur; Avogaro, Angelo

    2018-04-01

    In the SAVOR-TIMI trial, the risk of heart failure (HF) was increased by 27% in T2D patients randomized to the dipeptidyl peptidase-4 inhibitor (DPP4i) saxagliptin. Other studies have provided inconsistent results regarding this association. Herein, we performed a pharmacovigilance analysis of the rate of HF associated with DPP4is, focusing on stimulated reporting and moderation by drug-drug interactions. We mined the FDA adverse event (AE) reporting system (FAERS) from 2004q1 to 2017q3, including a total of 9906,642 AE reports. Rates (/1000 reports) of HF within the reports for DPP4is and reports for other antidiabetic drugs were calculated for the period up to 2013q3 (date of publication of the SAVOR-TIMI trial results) and from 2013q4 to 2017q3. Analyses were refined by filtering according to therapeutic area, concomitant diseases and drugs, and competing AEs. The rate of HF among the AE reports filed for DPP4is significantly increased after 2013q3, especially for saxagliptin. When compared to non-insulin non-glitazone antidiabetic drugs, the proportional reporting ratio (PRR) of HF for DPP4is was 0.62 (95% CI 0.56-0.68) up to 2013q3 and 2.12 (95% CI 1.96-2.28) from 2013q4 to 2017q3. This stimulated reporting was consistent in subanalyses based on the presence/absence of cardiac disorders and after controlling for competing AEs. The rate of HF among AE reports for DPP4is was modestly moderated by the concomitant use of metformin (- 15%) and strongly moderated by the concomitant use of SGLT2 inhibitors (- 63%), even after excluding competing AEs. Within the FAERS, the association between HF and DPP4is was biased by stimulated reporting, implying that the publication of the SAVOR-TIMI trial and the subsequent regulatory warnings primed clinicians to report HF events in DPP4i users as drug-related AEs. The rate of HF associated with DPP4is was moderated when they were used in combination with SGLT2 inhibitors.

  12. Structure-Based Design of Peptidic Inhibitors of the Interaction between CC Chemokine Ligand 5 (CCL5) and Human Neutrophil Peptides 1 (HNP1)

    NARCIS (Netherlands)

    Wichapong, Kanin; Alard, Jean-Eric; Ortega-Gomez, Almudena; Weber, Christian; Hackeng, Tilman M.; Soehnlein, Oliver; Nicolaes, Gerry A. F.

    2016-01-01

    Protein-protein interactions (PPIs) are receiving increasing interest, much sparked by the realization that they represent druggable targets. Recently, we successfully developed a peptidic inhibitor, RRYGTSKYQ ("SKY" peptide), that shows high potential in vitro and in vivo to interrupt a PPI between

  13. Development of a high-throughput screening-compatible assay to identify inhibitors of the CK2alpha/CK2beta interaction

    DEFF Research Database (Denmark)

    Hochscherf, Jennifer; Lindenblatt, Dirk; Steinkrueger, Michaela

    2015-01-01

    Increased activity of protein kinase CK2 is associated with various types of cancer, neurodegenerative diseases, and chronic inflammation. In the search for CK2 inhibitors, attention has expanded toward compounds disturbing the interaction between CK2alpha and CK2beta in addition to established a...

  14. Cell-permeable and plasma-stable peptidomimetic inhibitors of the postsynaptic density-95/N-methyl-D-aspartate receptor interaction

    DEFF Research Database (Denmark)

    Bach, Anders*; Eildal, Jonas Nii Nortey*; Stuhr-Hansen, Nicolai

    2011-01-01

    of this interaction, and here, this template is exploited for the development of blood plasma-stable and cell-permeable inhibitors. Initially, we explored both the amino acid sequence of the tetrapeptide and the nature of the N-alkyl groups, which consolidated N-cyclohexylethyl-ETAV (1) as the most potent...

  15. Structural Study of a New HIV-1 Entry Inhibitor and Interaction with the HIV-1 Fusion Peptide in Dodecylphosphocholine Micelles.

    Science.gov (United States)

    Pérez, Yolanda; Gómara, Maria José; Yuste, Eloísa; Gómez-Gutierrez, Patricia; Pérez, Juan Jesús; Haro, Isabel

    2017-08-25

    Previous studies support the hypothesis that the envelope GB virus C (GBV-C) E1 protein interferes the HIV-1 entry and that a peptide, derived from the region 139-156 of this protein, has been defined as a novel HIV-1 entry inhibitor. In this work, we firstly focus on the characterization of the structural features of this peptide, which are determinant for its anti-HIV-1 activity and secondly, on the study of its interaction with the proposed viral target (i.e., the HIV-1 fusion peptide). We report the structure of the peptide determined by NMR spectroscopy in dodecylphosphocholine (DPC) micelles solved by using restrained molecular dynamics calculations. The acquisition of different NMR experiments in DPC micelles (i.e., peptide-peptide titration, diffusion NMR spectroscopy, and addition of paramagnetic relaxation agents) allows a proposal of an inhibition mechanism. We conclude that a 18-mer peptide from the non-pathogenic E1 GBV-C protein, with a helix-turn-helix structure inhibits HIV-1 by binding to the HIV-1 fusion peptide at the membrane level, thereby interfering with those domains in the HIV-1, which are critical for stabilizing the six-helix bundle formation in a membranous environment. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. The Wheat Bax Inhibitor-1 Protein Interacts with an Aquaporin TaPIP1 and Enhances Disease Resistance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Pan-Pan Lu

    2018-01-01

    Full Text Available Bax inhibitor-1 (BI-1 is an endoplasmic reticulum (ER-resident cell death suppressor evolutionarily conserved in eukaryotes. The ability of BI-1 to inhibit the biotic and abiotic stresses have been well-studied in Arabidopsis, while the functions of wheat BI-1 are largely unknown. In this study, the wheat BI-1 gene TaBI-1.1 was isolated by an RNA-seq analysis of Fusarium graminearum (Fg-treated wheat. TaBI-1.1 expression was induced by a salicylic acid (SA treatment and down-regulated by an abscisic acid (ABA treatment. Based on β-glucuronidase (GUS staining, TaBI-1.1 was expressed in mature leaves and roots but not in the hypocotyl or young leaves. Constitutive expression of TaBI-1.1 in Arabidopsis enhanced its resistance to Pseudomonas syringae pv. Tomato (Pst DC3000 infection and induced SA-related gene expression. Additionally, TaBI-1.1 transgenic Arabidopsis exhibited an alleviation of damage caused by high concentrations of SA and decreased the sensitivity to ABA. Consistent with the phenotype, the RNA-seq analysis of 35S::TaBI-1.1 and Col-0 plants showed that TaBI-1.1 was involved in biotic stresses. These results suggested that TaBI-1.1 positively regulates SA signals and plays important roles in the response to biotic stresses. In addition, TaBI-1.1 interacted with the aquaporin TaPIP1, and both them were localized to ER membrane. Furthermore, we demonstrated that TaPIP1 was up-regulated by SA treatment and TaPIP1 transgenic Arabidopsis enhanced the resistance to Pst DC3000 infection. Thus, the interaction between TaBI-1.1 and TaPIP1 on the ER membrane probably occurs in response to SA signals and defense response.

  17. Intramolecular interactions stabilizing compact conformations of the intrinsically disordered kinase-inhibitor domain of Sic1: a molecular dynamics investigation.

    Directory of Open Access Journals (Sweden)

    Matteo eLambrughi

    2012-11-01

    Full Text Available Cyclin-dependent kinase inhibitors (CKIs are key regulatory proteins of the eukaryotic cell cycle, which modulate cyclin-dependent kinase (Cdk activity. CKIs perform their inhibitory effect by the formation of ternary complexes with a target kinase and its cognate cyclin. These regulators generally belong to the class of intrinsically disordered proteins (IDPs, which lack a well-defined and organized three-dimensional structure in their free state, undergoing folding upon binding to specific partners. Unbound IDPs are not merely random-coil structures, but can present intrinsically folded structural units (IFSUs and collapsed conformations. These structural features can be relevant to protein function in vivo.The yeast CKI Sic1 is a 284-amino acid IDP that binds to Cdk1 in complex with the Clb5,6 cyclins, preventing phosphorylation of G1 substrates and, therefore, entrance to the S phase. Sic1 degradation, triggered by multiple phosphorylation events, promotes cell-cycle progression. Previous experimental studies pointed out a propensity of Sic1 and its isolated domains to populate both extended and compact conformations. The present contribution provides models of the compact conformations of the Sic1 kinase-inhibitory domain (KID by all-atom molecular-dynamics simulations in explicit solvent and in the absence of interactors. The results are integrated by spectroscopic and spectrometric data. Helical IFSUs are identified, along with networks of intramolecular interactions. The results identify a group of hub residues and electrostatic interactions which are likely to be involved in the stabilization of globular states.

  18. Comprehensive and Automated Linear Interaction Energy Based Binding-Affinity Prediction for Multifarious Cytochrome P450 Aromatase Inhibitors

    NARCIS (Netherlands)

    van Dijk, Marc; Ter Laak, Antonius M; Wichard, Jörg D; Capoferri, Luigi; Vermeulen, Nico P E; Geerke, Daan P

    2017-01-01

    Cytochrome P450 aromatase (CYP19A1) plays a key role in the development of estrogen dependent breast cancer, and aromatase inhibitors have been at the front line of treatment for the past three decades. The development of potent, selective and safer inhibitors is ongoing with in silico screening

  19. Drug-drug interactions with sodium-glucose cotransporters type 2 (SGLT2) inhibitors, new oral glucose-lowering agents for the management of type 2 diabetes mellitus.

    Science.gov (United States)

    Scheen, André J

    2014-04-01

    Inhibitors of sodium-glucose cotransporters type 2 (SGLT2) reduce hyperglycaemia by decreasing renal glucose threshold and thereby increasing urinary glucose excretion. They are proposed as a novel approach for the management of type 2 diabetes mellitus. They have proven their efficacy in reducing glycated haemoglobin, without inducing hypoglycaemia, as monotherapy or in combination with various other glucose-lowering agents, with the add-on value of promoting some weight loss and lowering arterial blood pressure. As they may be used concomitantly with many other drugs, we review the potential drug-drug interactions (DDIs) regarding the three leaders in the class (dapagliglozin, canagliflozin and empagliflozin). Most of the available studies were performed in healthy volunteers and have assessed the pharmacokinetic interferences with a single administration of the SGLT2 inhibitor. The exposure [assessed by peak plasma concentrations (Cmax) and area under the concentration-time curve (AUC)] to each SGLT2 inhibitor tested was not significantly influenced by the concomitant administration of other glucose-lowering agents or cardiovascular agents commonly used in patients with type 2 diabetes. Reciprocally, these medications did not influence the pharmacokinetic parameters of dapagliflozin, canagliflozin or empagliflozin. Some modest changes were not considered as clinically relevant. However, drugs that could specifically interfere with the metabolic pathways of SGLT2 inhibitors [rifampicin, inhibitors or inducers of uridine diphosphate-glucuronosyltransferase (UGT)] may result in significant changes in the exposure of SGLT2 inhibitors, as shown for dapagliflozin and canagliflozin. Potential DDIs in patients with type 2 diabetes receiving chronic treatment with an SGLT2 inhibitor deserve further attention, especially in individuals treated with several medications or in more fragile patients with hepatic and/or renal impairment.

  20. Interactive Effectiveness of Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers or Their Combination on Survival of Hemodialysis Patients

    Science.gov (United States)

    Kido, Ryo; Akizawa, Tadao; Fukagawa, Masafumi; Onishi, Yoshihiro; Yamaguchi, Takuhiro; Fukuhara, Shunichi

    2018-01-01

    Background Does the use of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers individually or as a combination confer a survival benefit in hemodialysis patients? The answer to this question is yet unclear. Methods We performed a case-cohort study using data from the Mineral and Bone Disorder Outcomes Study for Japanese CKD stage 5D patients (MBD-5D), a 3-year multicenter prospective case-cohort study, including 8,229 hemodialysis patients registered from 86 facilities in Japan. All patients had secondary hyperparathyroidism, a condition defined as a parathyroid hormone level ≥180 pg/mL and/or receiving vitamin D receptor activators. We compared all-cause mortality rates between those receiving ACEI, ARB, and their combination and non-users with interaction testing. We used marginal structural Poisson regression (causal model) to estimate the causal effect and interaction adjusted for possible time-dependent confounding. Cardiovascular mortality was also evaluated. Results Among 3,762 randomly sampled subcohort patients, those taking ACEI, ARB, and their combination at baseline accounted for 4.0, 31.6, and 3.8%, respectively. Over 3 years, 1,226 all-cause and 462 cardiovascular deaths occurred. Compared to non-users, ARB-alone users had a lower all-cause mortality rate (adjusted incident rate ratio [aIRR] 0.62, 95% CI 0.50–0.76), whereas ACEI-alone users showed a statistically similar rate (aIRR 1.01, 95% CI 0.57–1.77). On the contrary, combination users had a greater mortality rate (aIRR 2.56, 95% CI 1.22–5.37), showing significant interaction (p = 0.03). Analysis for cardiovascular mortality showed similar results. Conclusion Among hemodialysis patients with secondary hyperparathyroidism, unlike ACEI use, ARB use was associated with greater survival than non-use. Conversely, combination use was associated with greater mortality. Controlled trials are warranted to verify the causality factors of these associations. PMID:29161689

  1. Crystallographic Study of a Novel Sub-Nanomolar Inhibitor Provides Insight on the Binding Interactions of Alkenyldiarylmethanes with Human Immunodeficiency Virus-1 (HIV-1) Reverse Transcriptase†

    Science.gov (United States)

    Cullen, Matthew D.; Ho, William C.; Bauman, Joseph D.; Das, Kalyan; Arnold, Eddy; Hartman, Tracy L.; Watson, Karen M.; Buckheit, Robert W.; Pannecouque, Christophe; De Clercq, Erik; Cushman, Mark

    2009-01-01

    Two crystal structures have been solved for separate complexes of alkenyldiarylmethane (ADAM) non-nucleoside reverse transcriptase inhibitors (NNRTI) 3 and 4 with HIV-1 reverse transcriptase (RT). The structures reveal inhibitor binding is exclusively hydrophobic in nature and the shape of the inhibitor-bound NNRTI binding pocket is unique among other reported inhibitor-RT crystal structures. Primarily, ADAMs 3 and 4 protrude from a large gap in the backside of the binding pocket, placing portions of the inhibitors unusually close to the polymerase active site and allowing 3 to form a weak hydrogen bond with Lys223. The lack of additional stabilizing interactions, beyond the observed hydrophobic surface contacts, between 4 and RT is quite perplexing given the extreme potency of the compound (IC50 ≤ nM). ADAM 4 was designed to be hydrolytically stable in blood plasma, and an investigation of its hydrolysis in rat plasma demonstrated it has a significantly prolonged half-life in comparison to ADAM lead compounds 1 and 2. PMID:19775161

  2. Interaction of inhibitors with corrosion scale formed on N80 steel in CO{sub 2}-saturated NaCl solution

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D. [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Hubei Key Laboratory of Materials Chemistry and Service Failure, Wuhan (China); School of Chemical Engineering and Pharmacy, Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan (China); Qiu, Y.B.; Guo, X.P. [School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Hubei Key Laboratory of Materials Chemistry and Service Failure, Wuhan (China); Tomoe, Y.; Bando, K. [Japan Oil, Gas and Metals National Corporation, The Former Japan National Oil Corporation, Hamada, Mihama-ku, Chiba-City, Chiba (Japan)

    2011-12-15

    The performance of the selected inhibitors, including thioglycolic acid (TGA), diethylenetriamine (DETA), and naphthene acid imidazolines (IM), on the bare surface of N80 steel and its scaled surface pre-corroded in CO{sub 2}-saturated 1%NaCl solution was investigated by weight-loss method, electrochemical measurements using rotating cylinder electrode and surface analytical methods (SEM, XRD, and EPMA). The results indicate that there is a remarkable difference in inhibition efficiency of inhibitors on the N80 steel with and without pre-corrosion scale. The synergistic effect between inhibitors and corrosion scale not only depends on the size of inhibitor molecules, but also depends on the interaction of the inhibitor with the corrosion scale. It shows that IM and DETA have a good positive synergistic effect with the corrosion scale formed on N80 steel, although DETA has no inhibition efficiency for bare N80 steel, which can easily enter into the apertures of the corrosion scale, and block the active sites on the metal surface and the diffusion routeways of the reactant so as to depress the corrosion of the substrate metal. While TGA shows excellent inhibition efficiency on bare N80 steel, but it has an antagonistic effect with the corrosion scale although it has a small molecular weight as well as DETA, because TGA can dissolve corrosion scale and break its integrality and protectiveness performance. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Apigenin induces apoptosis by targeting inhibitor of apoptosis proteins and Ku70–Bax interaction in prostate cancer

    Science.gov (United States)

    Shukla, Sanjeev; Fu, Pingfu; Gupta, Sanjay

    2014-01-01

    Dysfunction of the apoptotic pathway in prostate cancer cells confers apoptosis resistance towards various therapies. A novel strategy to overcome resistance is to directly target the apoptotic pathway in cancer cells. Apigenin, an anticancer agent, selectively toxic to cancer cells induces cell cycle arrest and apoptosis through mechanisms which are not fully explored. In the present study we provide novel insight into the mechanisms of apoptosis induction by apigenin. Treatment of androgen-refractory human prostate cancer PC-3 and DU145 cells with apigenin resulted in dose-dependent suppression of XIAP, c-IAP1, c-IAP2 and survivin protein levels. Apigenin treatment resulted in significant decrease in cell viability and apoptosis induction with the increase of cytochrome C in time-dependent manner. These effects of apigenin were accompanied by decrease in Bcl-xL and Bcl-2 and increase in the active form of Bax protein. The apigenin-mediated increase in Bax was due to dissociation of Bax from Ku70 which is essential for apoptotic activity of Bax. Apigenin treatment resulted in the inhibition of class I histone deacetylases and HDAC1 protein expression, thereby increasing the acetylation of Ku70 and the dissociation of Bax resulting in apoptosis of cancer cells. Furthermore, apigenin significantly reduced HDAC1 occupancy at the XIAP promoter, suggesting that histone deacetylation might be critical for XIAP downregulation. These results suggest that apigenin targets inhibitor of apoptosis proteins and Ku70–Bax interaction in the induction of apoptosis in prostate cancer cells and in athymic nude mouse xenograft model endorsing its in vivo efficacy. PMID:24563225

  4. The glycine reuptake inhibitor org 25935 interacts with basal and ethanol-induced dopamine release in rat nucleus accumbens.

    Science.gov (United States)

    Lidö, Helga Höifödt; Stomberg, Rosita; Fagerberg, Anne; Ericson, Mia; Söderpalm, Bo

    2009-07-01

    The mesolimbic dopamine (DA) projection from the ventral tegmental area to nucleus accumbens (nAc), a central part of the reward system, is activated by ethanol (EtOH) and other drugs of abuse. We have previously demonstrated that the glycine receptor in the nAc and its amino acid agonists may be implicated in the DA activation and reinforcing properties of EtOH. We have also reported that the glycine transporter 1 inhibitor, Org 25935, produces a robust and dose-dependent decrease in EtOH consumption in Wistar rats. The present study explores the interaction between EtOH and Org 25935 with respect to DA levels in the rat nAc. The effects of Org 25935 (6 mg/kg, i.p.) and/or EtOH (2.5 g/kg, i.p.) on accumbal DA levels were examined by means of in vivo microdialysis (coupled to HPLC-ED) in freely moving male Wistar rats. The effect of Org 25935 on accumbal glycine output was also investigated. Systemic Org 25935 increased DA output in a subpopulation of rats (52% in Experiment 1 and 38% in Experiment 2). In Experiment 2, EtOH produced a significant increase in DA levels in vehicles (35%) and in Org 25935 nonresponders (19%), whereas EtOH did not further increase the DA level in rats responding to Org 25935 (2%). The same dose of Org 25935 increased glycine levels by 87% in nAc. This study demonstrates that Org 25935, probably via increased glycine levels, (i) counteracts EtOH-induced increases of accumbal DA levels and (ii) increases basal DA levels in a subpopulation of rats. The results are in line with previous findings and it is suggested that the effects observed involve interference with accumbal GlyRs and are related to the alcohol consumption modulating effect of Org 25935.

  5. Histone deacetylase inhibitor trichostatin A resensitizes gemcitabine resistant urothelial carcinoma cells via suppression of TG-interacting factor

    International Nuclear Information System (INIS)

    Yeh, Bi-Wen; Li, Wei-Ming; Li, Ching-Chia; Kang, Wan-Yi; Huang, Chun-Nung; Hour, Tzyh-Chyuan; Liu, Zi-Miao

    2016-01-01

    Gemcitabine and cisplatin (GC) has been widely used for advanced and metastatic urothelial carcinoma (UC). However, resistance to this remedy has been noticed. We have demonstrated that increase of TG-interacting factor (TGIF) in specimens is associated with worse prognosis of upper tract UC (UTUC) patients. The roles of TGIF in the gemcitabine resistance of UC were explored. Specimens of 23 locally advanced/advanced stage UTUC patients who received GC systemic chemotherapy after radical nephroureterectomy were collected to evaluate the alterations of TGIF in the resistance to the remedy by using immunohistochemistry. In vitro characterizations of mechanisms mediating TGIF in gemcitabine resistance were conducted by analyzing NTUB1 cells and their gemcitabine-resistant subline, NGR cells. Our results show that increased TGIF is significantly associated with chemo-resistance, poor progression-free survival, and higher cancer-related deaths of UTUC patients. Higher increases of TGIF, p-AKT Ser473 and invasive ability were demonstrated in NGR cells. Overexpression of TGIF in NTUB1 cells upregulated p-AKT Ser473 activation, enhanced migration ability, and attenuated cellular sensitivity to gemcitabine. Knockdown of TGIF in NGR cells downregulated p-AKT Ser473 activation, declined migration ability, and enhanced cellular sensitivity to gemcitabine. In addition, histone deacetylases inhibitor trichostatin A (TSA) inhibited TGIF, p-AKT Ser473 expression and migration ability. Synergistic effects of gemcitabine and TSA on NGR cells were also demonstrated. Collectively, TGIF contributes to the gemcitabine resistance of UC via AKT activation. Combined treatment with gemcitabine and TSA might be a promising therapeutic remedy to improve the gemcitabine resistance of UC. - Highlights: • TGIF expression in UC cells is associated with chemoresistance to gemcitabine. • TGIF-regulated AKT activation contributes to the gemcitabine resistance. • Increased TGIF is significantly

  6. Histone deacetylase inhibitor trichostatin A resensitizes gemcitabine resistant urothelial carcinoma cells via suppression of TG-interacting factor

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, Bi-Wen [Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan (China); Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Urology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Li, Wei-Ming [Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Urology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Li, Ching-Chia [Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Urology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Urology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Kang, Wan-Yi [Department of Pathology, Kuo General Hospital, Tainan 701, Taiwan (China); Huang, Chun-Nung [Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Urology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Hour, Tzyh-Chyuan [Institute of Biochemistry, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Liu, Zi-Miao [Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan (China); and others

    2016-01-01

    Gemcitabine and cisplatin (GC) has been widely used for advanced and metastatic urothelial carcinoma (UC). However, resistance to this remedy has been noticed. We have demonstrated that increase of TG-interacting factor (TGIF) in specimens is associated with worse prognosis of upper tract UC (UTUC) patients. The roles of TGIF in the gemcitabine resistance of UC were explored. Specimens of 23 locally advanced/advanced stage UTUC patients who received GC systemic chemotherapy after radical nephroureterectomy were collected to evaluate the alterations of TGIF in the resistance to the remedy by using immunohistochemistry. In vitro characterizations of mechanisms mediating TGIF in gemcitabine resistance were conducted by analyzing NTUB1 cells and their gemcitabine-resistant subline, NGR cells. Our results show that increased TGIF is significantly associated with chemo-resistance, poor progression-free survival, and higher cancer-related deaths of UTUC patients. Higher increases of TGIF, p-AKT{sup Ser473} and invasive ability were demonstrated in NGR cells. Overexpression of TGIF in NTUB1 cells upregulated p-AKT{sup Ser473} activation, enhanced migration ability, and attenuated cellular sensitivity to gemcitabine. Knockdown of TGIF in NGR cells downregulated p-AKT{sup Ser473} activation, declined migration ability, and enhanced cellular sensitivity to gemcitabine. In addition, histone deacetylases inhibitor trichostatin A (TSA) inhibited TGIF, p-AKT{sup Ser473} expression and migration ability. Synergistic effects of gemcitabine and TSA on NGR cells were also demonstrated. Collectively, TGIF contributes to the gemcitabine resistance of UC via AKT activation. Combined treatment with gemcitabine and TSA might be a promising therapeutic remedy to improve the gemcitabine resistance of UC. - Highlights: • TGIF expression in UC cells is associated with chemoresistance to gemcitabine. • TGIF-regulated AKT activation contributes to the gemcitabine resistance. • Increased

  7. 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.

  8. An α‐Helix‐Mimicking 12,13‐Helix: Designed α/β/γ‐Foldamers as Selective Inhibitors of Protein–Protein Interactions

    Science.gov (United States)

    Grison, Claire M.; Miles, Jennifer A.; Robin, Sylvie

    2016-01-01

    Abstract A major current challenge in bioorganic chemistry is the identification of effective mimics of protein secondary structures that act as inhibitors of protein–protein interactions (PPIs). In this work, trans‐2‐aminocyclobutanecarboxylic acid (tACBC) was used as the key β‐amino acid component in the design of α/β/γ‐peptides to structurally mimic a native α‐helix. Suitably functionalized α/β/γ‐peptides assume an α‐helix‐mimicking 12,13‐helix conformation in solution, exhibit enhanced proteolytic stability in comparison to the wild‐type α‐peptide parent sequence from which they are derived, and act as selective inhibitors of the p53/hDM2 interaction. PMID:27467859

  9. An α-Helix-Mimicking 12,13-Helix: Designed α/β/γ-Foldamers as Selective Inhibitors of Protein-Protein Interactions.

    Science.gov (United States)

    Grison, Claire M; Miles, Jennifer A; Robin, Sylvie; Wilson, Andrew J; Aitken, David J

    2016-09-05

    A major current challenge in bioorganic chemistry is the identification of effective mimics of protein secondary structures that act as inhibitors of protein-protein interactions (PPIs). In this work, trans-2-aminocyclobutanecarboxylic acid (tACBC) was used as the key β-amino acid component in the design of α/β/γ-peptides to structurally mimic a native α-helix. Suitably functionalized α/β/γ-peptides assume an α-helix-mimicking 12,13-helix conformation in solution, exhibit enhanced proteolytic stability in comparison to the wild-type α-peptide parent sequence from which they are derived, and act as selective inhibitors of the p53/hDM2 interaction. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  10. Raman spectroscopic studies of the interaction of oxalic acid and sodium oxalate used as corrosion inhibitors with copper

    Science.gov (United States)

    Jeziorowski, H.; Moser, B.

    1985-09-01

    The Raman spectra of the liquid-solid interface recorded in situ show the formation of a salt complex of the inhibitor molecules and the copper ions. This suggests that this chemisorbed surface species produces the protective layer.

  11. Proton NMR studies of Cucurbita maxima trypsin inhibitors: Evidence for pH-dependent conformational change and his25 - try27 interaction

    Energy Technology Data Exchange (ETDEWEB)

    Krishnamoorthi, R.; Chanlan Sun Lin; Yuxi Gong (Kansas State Univ., Manhattan (United States)); VanderVelde, D. (Univ. of Kansas, Lawrence (United States)); Hahn, K. (Univ. of Colorado, Denver (United States))

    1992-01-28

    A pH-dependent His25-Tyr27 interaction was demonstrated in the case of Cucurbita maxima trypsin inhibitors (CMTI-I and CMTI-III) by means of nuclear magnetic resonance (NMR) spectroscopy. pH titration, line widths, peak shapes, deuterium exchange kinetics, and two-dimensional nuclear Overhauser effect spectroscopy (NOESY) were employed to characterize a conformational change involving Tyr27, which was shown to be triggered by deprotonation of His25 around pH 6. A hydrogen bond is proposed to be formed between N{sub {epsilon}} of His25 and OH of Tyr27, as a distance between the atoms, His25 N{epsilon} and Tyr25 OH, of 3.02 {angstrom} is consistent with a model built with NOE-derived distance constraints. The presently characterized relative orientations of His25 and Tyr27 are of functional significance, as these residues make contact with the enzyme in the enzyme-inhibitor complex. Furthermore, trypsin assay and inhibitor-binding studies showed that conformations of trypsin and the squash inhibitor complex. Furthermore, trypsin assay and inhibitor-binding studies showed that conformations of trypsin and the squash inhibitor were functionally relevant only in the pH range 6-8. The pK{sub a} of His25 was determined and found to be influenced by Glu9/Lys substitution and by the hydrolysis of the reactive-site peptide bond between Arg5 and Ile6. As these sites are located far (>10 {angstrom}) from His25, the results point out conformational changes that are propagated to a distant site in the protein molecule.

  12. [Predictive factors of clinically significant drug-drug interactions among regimens based on protease inhibitors, non-nucleoside reverse transcriptase inhibitors and raltegravir].

    Science.gov (United States)

    Cervero, Miguel; Torres, Rafael; Jusdado, Juan José; Pastor, Susana; Agud, Jose Luis

    2016-04-15

    To determine the prevalence and types of clinically significant drug-drug interactions (CSDI) in the drug regimens of HIV-infected patients receiving antiretroviral treatment. retrospective review of database. Centre: Hospital Universitario Severo Ochoa, Infectious Unit. one hundred and forty-two participants followed by one of the authors were selected from January 1985 to December 2014. from their outpatient medical records we reviewed information from the last available visit of the participants, in relation to HIV infection, comorbidities, demographics and the drugs that they were receiving; both antiretroviral drugs and drugs not related to HIV infection. We defined CSDI from the information sheet and/or database on antiretroviral drug interactions of the University of Liverpool (http://www.hiv-druginteractions.org) and we developed a diagnostic tool to predict the possibility of CSDI. By multivariate logistic regression analysis and by estimating the diagnostic performance curve obtained, we identified a quick tool to predict the existence of drug interactions. Of 142 patients, 39 (29.11%) had some type of CSDI and in 11.2% 2 or more interactions were detected. In only one patient the combination of drugs was contraindicated (this patient was receiving darunavir/r and quetiapine). In multivariate analyses, predictors of CSDI were regimen type (PI or NNRTI) and the use of 3 or more non-antiretroviral drugs (AUC 0.886, 95% CI 0.828 to 0.944; P=.0001). The risk was 18.55 times in those receiving NNRTI and 27,95 times in those receiving IP compared to those taking raltegravir. Drug interactions, including those defined as clinically significant, are common in HIV-infected patients treated with antiretroviral drugs, and the risk is greater in IP-based regimens. Raltegravir-based prescribing, especially in patients who receive at least 3 non-HIV drugs could avoid interactions. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  13. Biochemical investigations of the mechanism of action of small molecules ZL006 and IC87201 as potential inhibitors of the nNOS-PDZ/PSD-95-PDZ interactions

    DEFF Research Database (Denmark)

    Bach, Anders

    2015-01-01

    ZL006 and IC87201 have been presented as efficient inhibitors of the nNOS/PSD-95 protein-protein interaction and shown great promise in cellular experiments and animal models of ischemic stroke and pain. Here, we investigate the proposed mechanism of action of ZL006 and IC87201 using biochemical...... by interacting with the β-finger of nNOS-PDZ. Our findings have implications for further medicinal chemistry efforts of ZL006, IC87201 and analogues, and challenge the general and widespread view on their mechanism of action....

  14. Effects of BTS (N-benzyl-p-toluene sulphonamide), an inhibitor for myosin-actin interaction, on myofibrillogenesis in skeletal muscle cells in culture.

    Science.gov (United States)

    Kagawa, Maiko; Sato, Naruki; Obinata, Takashi

    2006-11-01

    Actin filaments align around myosin filaments in the correct polarity and in a hexagonal arrangement to form cross-striated structures. It has been postulated that this myosin-actin interaction is important in the initial phase of myofibrillogenesis. It was previously demonstrated that an inhibitor of actin-myosin interaction, BDM (2,3-butanedione monoxime), suppresses myofibril formation in muscle cells in culture. However, further study showed that BDM also exerts several additional effects on living cells. In this study, we further examined the role of actin-myosin interaction in myofibril assembly in primary cultures of chick embryonic skeletal muscle by applying a more specific inhibitor, BTS (N-benzyl-p-toluene sulphonamide), of myosin ATPase and actin-myosin interaction. The assembly of sarcomeric structures from myofibrillar proteins was examined by immunocytochemical methods with the application of BTS to myotubes just after fusion. Addition of BTS (10-50 microM) significantly suppressed the organization of actin and myosin into cross-striated structures. BTS also interfered in the organization of alpha-actinin, C-protein (or MyBP-C), and connectin (or titin) into ordered striated structures, though the sensitivity was less. Moreover, when myotubes cultured in the presence of BTS were transferred to a control medium, sarcomeric structures were formed in 2-3 days, indicating that the inhibitory effect of BTS on myotubes is reversible. These results show that actin-myosin interaction plays a critical role in the process of myofibrillogenesis.

  15. Hepatitis C virus inhibitor synergism suggests multistep interactions between heat-shock protein 90 and hepatitis C virus replication

    Science.gov (United States)

    Kubota, Naoko; Nomoto, Masataka; Hwang, Gi-Wook; Watanabe, Toshihiko; Kohara, Michinori; Wakita, Takaji; Naganuma, Akira; Kuge, Shusuke

    2016-01-01

    AIM: To address the effect of heat-shock protein 90 (HSP90) inhibitors on the release of the hepatitis C virus (HCV), a cell culture-derived HCV (JFH1/HCVcc) from Huh-7 cells was examined. METHODS: We quantified both the intracellular and extracellular (culture medium) levels of the components (RNA and core) of JFH-1/HCVcc. The intracellular HCV RNA and core levels were determined after the JFH1/HCVcc-infected Huh-7 cells were treated with radicicol for 36 h. The extracellular HCV RNA and core protein levels were determined from the medium of the last 24 h of radicicol treatment. To determine the possible role of the HSP90 inhibitor in HCV release, we examined the effect of a combined application of low doses of the HSP90 inhibitor radicicol and the RNA replication inhibitors cyclosporin A (CsA) or interferon. Finally, we statistically examined the combined effect of radicicol and CsA using the combination index (CI) and graphical representation proposed by Chou and Talalay. RESULTS: We found that the HSP90 inhibitors had greater inhibitory effects on the HCV RNA and core protein levels measured in the medium than inside the cells. This inhibitory effect was observed in the presence of a low level of a known RNA replication inhibitor (CsA or interferon-α). Treating the cells with a combination of radicicol and cyclosporin A for 24 h resulted in significant synergy (CI < 1) that affected the release of both the viral RNA and the core protein. CONCLUSION: In addition to having an inhibitory effect on RNA replication, HSP90 inhibitors may interfere with an HCV replication step that occurs after the synthesis of viral RNA, such as assembly and release. PMID:26925202

  16. Affinity and specificity of serine endopeptidase-protein inhibitor interactions. Empirical free energy calculations based on X-ray crystallographic structures.

    Science.gov (United States)

    Krystek, S; Stouch, T; Novotny, J

    1993-12-05

    An empirical function was used to calculate free energy change (delta G) of complex formation between the following inhibitors and enzymes: Kunitz inhibitor (BPTI) with trypsin, trypsinogen and kallikrein; turkey ovomucoid 3rd domain (OMTKY3) with alpha-chymotrypsin and the Streptomyces griseus protease B; the potato chymotrypsin inhibitor with the protease B; and the barely chymotrypsin inhibitor and eglin-c with subtilisin and thermitase. Using X-ray coordinates of the nine complexes, we estimated the contributions that hydrophobic effect, electrostatic interactions and side-chain conformational entropy make towards the stability of the complexes. The calculated delta G values showed good agreement with the experimentally measured ones, the only exception being the kallikrein/BPTI complex whose X-ray structure was solved at an exceptionally low pH. In complexes with different enzymes, the same inhibitor residues contributed identically towards complex formation (delta G(residue) Spearman rank correlation coefficient 0.7 to 1.0). The most productive enzyme-contacting residues in OMTKY3, eglin-c, and the chymotrypsin inhibitors were found in analogous positions on their respective binding loops; thus, our calculations identified a functional (energetic) motif that parallels the well-known structural similarity of the binding loops. The delta G values calculated for BPTI complexed with trypsin (-21.7 kcal) and trypsinogen (-23.4 kcal) were similar and close to the experimental delta G value of the trypsin/BPTI complex (-18.1 kcal), lending support to the suggestion that the 10(7) difference in the observed stabilities (KA) of these two complexes reflects the energetic cost of conformational changes induced in trypsinogen during the pre-equilibrium stages of complex formation. In almost all of the complexes studied, the stabilization free energy contributed by the inhibitors was larger than that donated by the enzymes. In the trypsin-BPTI complex, the calculated

  17. A drug-drug interaction study to assess the effect of the CYP1A2 inhibitor fluvoxamine on the pharmacokinetics of dovitinib (TKI258) in patients with advanced solid tumors

    NARCIS (Netherlands)

    de Weger, Vincent A; Goel, Sanjay; von Moos, Roger; Schellens, Jan H M; Mach, Nicholas; Tan, Eugene; Anand, Suraj; Scott, Jeffrey W; Lassen, Ulrik N

    PURPOSE: Dovitinib is an orally available multi tyrosine kinase inhibitor which inhibits VEGFR 1-3, FGFR 1-3, and PDGFR. This study was performed to investigate the potential drug-drug interaction of dovitinib with the CYP1A2 inhibitor fluvoxamine in patients with advanced solid tumors. METHODS:

  18. A drug-drug interaction study to assess the effect of the CYP1A2 inhibitor fluvoxamine on the pharmacokinetics of dovitinib (TKI258) in patients with advanced solid tumors

    DEFF Research Database (Denmark)

    de Weger, Vincent A; Goel, Sanjay; von Moos, Roger

    2018-01-01

    PURPOSE: Dovitinib is an orally available multi tyrosine kinase inhibitor which inhibits VEGFR 1-3, FGFR 1-3, and PDGFR. This study was performed to investigate the potential drug-drug interaction of dovitinib with the CYP1A2 inhibitor fluvoxamine in patients with advanced solid tumors. METHODS: ...

  19. Role of 5'TG3'-interacting factors (TGIFs) in Vorinostat (HDAC inhibitor)-mediated Corneal Fibrosis Inhibition.

    Science.gov (United States)

    Sharma, Ajay; Sinha, Nishant R; Siddiqui, Saad; Mohan, Rajiv R

    2015-01-01

    We have previously reported that vorinostat, an FDA-approved, clinically used histone deacetylase (HDAC) inhibitor, attenuates corneal fibrosis in vivo in rabbits by blocking transforming growth factor β (TGFβ). The 5'TG3'-interacting factors (TGIFs) are transcriptional repressors of TGFβ1 signaling via the Smad pathway. The present study was designed to explore the expression of TGIFs in human corneal fibroblasts and to investigate their role in mediating the antifibrotic effect of vorinostat. Human corneal fibroblast cultures were generated from donor corneas. RNA isolation, cDNA preparation, and PCR were performed to detect the presence of TGIF1 and TGIF2 transcripts. The cultures were exposed to vorinostat (2.5 µM) to test its effect on TGIF mRNA and protein levels using qPCR and immunoblotting. Myofibroblast formation was induced with TGFβ1 (5 ng/ml) treatment under serum-free conditions. The changes in fibrosis parameters were quantified by measuring fibrosis marker α-smooth muscle actin (αSMA) mRNA and protein levels with qPCR, immunostaining, and immunoblotting. Smad2/3/4 and TGIF knockdowns were performed using pre-validated RNAi/siRNAs and a commercially available transfection reagent. Human corneal fibroblasts showed the expression of TGIF1 and TGIF2. Vorinostat (2.5 µM) caused a 2.8-3.3-fold increase in TGIF1 and TGIF2 mRNA levels and a 1.4-1.8-fold increase in TGIF1 and TGIF2 protein levels. Vorinostat treatment also caused a significant increase in acetylhistone H3 and acetylhistone H4. Vorinostat-induced increases in TGIF1 and TGIF2 were accompanied by a concurrent decrease in corneal fibrosis, as indicated by a decrease in αSMA mRNA by 83±7.7% and protein levels by 97±5%. The RNAi-mediated knockdown of Smad2, Smad3, and Smad4 markedly attenuated TGFβ1-evoked transdifferentiation of fibroblasts to myofibroblasts. The siRNA-mediated knockdown of TGIF1 and TGIF2 neutralized vorinostat-evoked decreases in αSMA mRNA by 31%-45% and protein

  20. Study of Structure-active Relationship for Inhibitors of HIV-1 Integrase LEDGF/p75 Interaction by Machine Learning Methods.

    Science.gov (United States)

    Li, Yang; Wu, Yanbin; Yan, Aixia

    2017-07-01

    HIV-1 integrase (IN) is a promising target for anti-AIDS therapy, and LEDGF/p75 is proved to enhance the HIV-1 integrase strand transfer activity in vitro. Blocking the interaction between IN and LEDGF/p75 is an effective way to inhibit HIV replication infection. In this work, 274 LEDGF/p75-IN inhibitors were collected as the dataset. Support Vector Machine (SVM), Decision Tree (DT), Function Tree (FT) and Random Forest (RF) were applied to build several computational models for predicting whether a compound is an active or weakly active LEDGF/p75-IN inhibitor. Each compound is represented by MACCS fingerprints and CORINA Symphony descriptors. The prediction accuracies for the test sets of all the models are over 70 %. The best model Model 3B built by FT obtained a prediction accuracy and a Matthews Correlation Coefficient (MCC) of 81.08 % and 0.62 on test set, respectively. We found that the hydrogen bond and hydrophobic interactions are important for the bioactivity of an inhibitor. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Insight into the binding interactions of CYP450 aromatase inhibitors with their target enzyme: a combined molecular docking and molecular dynamics study.

    Science.gov (United States)

    Galeazzi, Roberta; Massaccesi, Luca

    2012-03-01

    CYP450 aromatase catalyzes the terminal and rate-determining step in estrogen synthesis, the aromatization of androgens, and its inhibition is an efficient approach to treating estrogen-dependent breast cancer. Insight into the molecular basis of the interaction at the catalytic site between CYP450 aromatase inhibitors and the enzyme itself is required in order to design new and more active compounds. Hence, a combined molecular docking-molecular dynamics study was carried out to obtain the structure of the lowest energy association complexes of aromatase with some third-generation aromatase inhibitors (AIs) and with other novel synthesized letrozole-derived compounds which showed high in vitro activity. The results obtained clearly demonstrate the role of the pharmacophore groups present in the azaheterocyclic inhibitors (NSAIs)-namely the triazolic ring and highly functionalized aromatic moieties carrying H-bond donor or acceptor groups. In particular, it was pointed out that all of them can contribute to inhibition activity by interacting with residues of the catalytic cleft, but the amino acids involved are different for each compound, even if they belong to the same class. Furthermore, the azaheterocyclic group strongly coordinates with the Fe(II) of heme cysteinate in the most active NSAI complexes, while it prefers to adopt another orientation in less active ones.

  2. Interaction of the EGFR inhibitors gefitinib, vandetanib, pelitinib and neratinib with the ABCG2 multidrug transporter: implications for the emergence and reversal of cancer drug resistance.

    Science.gov (United States)

    Hegedüs, Csilla; Truta-Feles, Krisztina; Antalffy, Géza; Várady, György; Német, Katalin; Ozvegy-Laczka, Csilla; Kéri, György; Orfi, László; Szakács, Gergely; Settleman, Jeffrey; Váradi, András; Sarkadi, Balázs

    2012-08-01

    Human ABCG2 is a plasma membrane glycoprotein that provides physiological protection against xenobiotics. ABCG2 also significantly influences biodistribution of drugs through pharmacological tissue barriers and confers multidrug resistance to cancer cells. Moreover, ABCG2 is the molecular determinant of the side population that is characteristically enriched in normal and cancer stem cells. Numerous tumors depend on unregulated EGFR signaling, thus inhibition of this receptor by small molecular weight inhibitors such as gefitinib, and the novel second generation agents vandetanib, pelitinib and neratinib, is a promising therapeutic option. In the present study, we provide detailed biochemical characterization regarding the interaction of these EGFR inhibitors with ABCG2. We show that ABCG2 confers resistance to gefitinib and pelitinib, whereas the intracellular action of vandetanib and neratinib is unaltered by the presence of the transporter. At higher concentrations, however, all these EGFR inhibitors inhibit ABCG2 function, thereby promoting accumulation of ABCG2 substrate drugs. We also report enhanced expression of ABCG2 in gefitinib-resistant non-small cell lung cancer cells, suggesting potential clinical relevance of ABCG2 in acquired drug resistance. Since ABCG2 has important impact on both the pharmacological properties and anti-cancer efficiencies of drugs, our results regarding the novel EGFR inhibitors should provide useful information about their therapeutic applicability against ABCG2-expressing cancer cells depending on EGFR signaling. In addition, the finding that these EGFR inhibitors efficiently block ABCG2 function may help to design novel drug-combination therapeutic strategies. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Setting up a Bioluminescence Resonance Energy Transfer high throughput screening assay to search for protein/protein interaction inhibitors in mammalian cells.

    Directory of Open Access Journals (Sweden)

    Cyril eCouturier

    2012-09-01

    Full Text Available Each step of the cell life and its response or adaptation to its environment are mediated by a network of protein/protein interactions termed interactome. Our knowledge of this network keeps growing due to the development of sensitive techniques devoted to study these interactions. The bioluminescence resonance energy transfer (BRET technique was primarily developed to allow the dynamic monitoring of protein-protein interactions in living cells, and has widely been used to study receptor activation by intra- or extra-molecular conformational changes within receptors and activated complexes in mammal cells. Some interactions are described as crucial in human pathological processes, and a new class of drugs targeting them has recently emerged. The BRET method is well suited to identify inhibitors of protein-protein interactions and here is described why and how to set up and optimize a High Throughput Screening assay based on BRET to search for such inhibitory compounds. The different parameters to take into account when developing such BRET assays in mammal cells are reviewed to give general guidelines: considerations on the targeted interaction, choice of BRET version, inducibility of the interaction, kinetic of the monitored interaction, and of the BRET reading, influence substrate concentration, number of cells and medium composition used on the Z’ factor, and expected interferences for colored or fluorescent compounds.

  4. The role of a second-shell residue in modifying substrate and inhibitor interactions in the SHV beta-lactamase: a study of ambler position Asn276.

    Science.gov (United States)

    Drawz, Sarah M; Bethel, Christopher R; Hujer, Kristine M; Hurless, Kelly N; Distler, Anne M; Caselli, Emilia; Prati, Fabio; Bonomo, Robert A

    2009-06-02

    Inhibitor-resistant class A beta-lactamases of the TEM and SHV families that arise by single amino acid substitutions are a significant threat to the efficacy of beta-lactam/beta-lactamase inhibitor combinations. To better understand the basis of the inhibitor-resistant phenotype in SHV, we performed mutagenesis to examine the role of a second-shell residue, Asn276. Of the 19 variants expressed in Escherichia coli, only the Asn276Asp enzyme demonstrated reduced susceptibility to ampicillin/clavulanate (MIC increased from 50/2 --> 50/8 microg/mL) while maintaining high-level resistance to ampicillin (MIC = 8192 microg/mL). Steady-state kinetic analyses of Asn276Asp revealed slightly diminished k(cat)/K(m) for all substrates tested. In contrast, we observed a 5-fold increase in K(i) for clavulanate (7.4 +/- 0.9 microM for Asn276Asp vs 1.4 +/- 0.2 microM for SHV-1) and a 40% reduction in k(inact)/K(I) (0.013 +/- 0.002 microM(-1 )s(-1) for Asn276Asp vs 0.021 +/- 0.004 microM(-1) s(-1) for SHV-1). Timed electrospray ionization mass spectrometry of clavulanate-inhibited SHV-1 and SHV Asn276Asp showed nearly identical mass adducts, arguing for a similar pathway of inactivation. Molecular modeling shows that novel electrostatic interactions are formed between Arg244Neta2 and both 276AspOdelta1 and Odelta2; these new forces restrict the spatial position of Arg244, a residue important in the recognition of the C(3)/C(4) carboxylate of beta-lactam substrates and inhibitors. Testing the functional consequences of this interaction, we noted considerable free energy costs (+DeltaDeltaG) for substrates and inhibitors. A rigid carbapenem (meropenem) was most affected by the Asn276Asp substitution (46-fold increase in K(i) vs SHV-1). We conclude that residue 276 is an important second-shell residue in class A beta-lactamase-mediated resistance to substrates and inhibitors, and only Asn is able to precisely modulate the conformational flexibility of Arg244 required for successful

  5. Proton NMR studies of Cucurbita maxima trypsin inhibitors: evidence for pH-dependent conformational change and His25-Tyr27 interaction.

    Science.gov (United States)

    Krishnamoorthi, R; Lin, C L; Gong, Y X; VanderVelde, D; Hahn, K

    1992-01-28

    A pH-dependent His25-Tyr27 interaction was demonstrated in the case of Cucurbita maxima trypsin inhibitors (CMTI-I and CMTI-III) by means of nuclear magnetic resonance (NMR) spectroscopy. pH titration, line widths, peak shapes, deuterium exchange kinetics, and two-dimensional nuclear Overhauser effect spectroscopy (NOESY) were employed to characterize a conformational change involving Tyr27, which was shown to be triggered by deprotonation of His25 around pH 6. A hydrogen bond is proposed to be formed between N epsilon of His25 and OH of Tyr27, as a distance between the atoms, His25 N epsilon and Tyr27 OH, of 3.02 A is consistent with a model built with NOE-derived distance constraints. Both the X-ray [Bode, W., Greyling, J.H., Huber, R., Otlewski, J., & Wilusz, T. (1989) FEBS Lett. 242, 282-292] and NMR [Holak, T.A., Gondol, D., Otlewski, J., & Wilusz, T. (1989) J. Mol. Biol. 210, 635-648] structures of CMTI-I at low pH (4.7-5.3) rule out such an interaction between the two aromatic rings, as the ring planes are oriented about 10 A away from each other. The presently characterized relative orientations of His25 and Tyr27 are of functional significance, as these residues make contact with the enzyme in the enzyme-inhibitor complex. Furthermore, trypsin assay and inhibitor-binding studies showed that conformations of trypsin and the squash inhibitor were functionally relevant only in the pH range 6-8. The pKa of His25 was determined and found to be influenced by Glu9/Lys substitution and by the hydrolysis of the reactive-site peptide bond between Arg5 and Ile6.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Interactions of plasminogen activator inhibitor-1 with vitronectin involve an extensive binding surface and induce mutual conformational rearrangements

    DEFF Research Database (Denmark)

    Blouse, Grant E; Dupont, Daniel Miotto; Schar, Christine R

    2009-01-01

    In order to explore early events during the association of plasminogen activator inhibitor-1 (PAI-1) with its cofactor vitronectin, we have applied a robust strategy that combines protein engineering, fluorescence spectroscopy, and rapid reaction kinetics. Fluorescence stopped-flow experiments de...

  7. SUMO expression shortens the lag phase of Saccharomyces cerevisiae yeast growth caused by complex interactive effects of major mixed fermentation inhibitors found in hot-compressed water-treated lignocellulosic hydrolysate.

    Science.gov (United States)

    Jayakody, Lahiru N; Kadowaki, Masafumi; Tsuge, Keisuke; Horie, Kenta; Suzuki, Akihiro; Hayashi, Nobuyuki; Kitagaki, Hiroshi

    2015-01-01

    The complex inhibitory effects of inhibitors present in lignocellulose hydrolysate suppress the ethanol fermentation of Saccharomyces cerevisiae. Although the interactive inhibitory effects play important roles in the actual hydrolysate, few studies have investigated glycolaldehyde, the key inhibitor of hot-compressed water-treated lignocellulose hydrolysate. Given this challenge, we investigated the interactive effects of mixed fermentation inhibitors, including glycolaldehyde. First, we confirmed that glycolaldehyde was the most potent inhibitor in the hydrolysate and exerted interactive inhibitory effects in combination with major inhibitors. Next, through genome-wide analysis and megavariate data modeling, we identified SUMOylation as a novel potential mechanism to overcome the combinational inhibitory effects of fermentation inhibitors. Indeed, overall SUMOylation was increased and Pgk1, which produces an ATP molecule in glycolysis by substrate-level phosphorylation, was SUMOylated and degraded in response to glycolaldehyde. Augmenting the SUMO-dependent ubiquitin system in the ADH1-expressing strain significantly shortened the lag phase of growth, released cells from G2/M arrest, and improved energy status and glucose uptake in the inhibitor-containing medium. In summary, our study was the first to establish SUMOylation as a novel platform for regulating the lag phase caused by complex fermentation inhibitors.

  8. Two-way pharmacokinetic interaction studies between saxagliptin and cytochrome P450 substrates or inhibitors: simvastatin, diltiazem extended-release, and ketoconazole

    Directory of Open Access Journals (Sweden)

    Patel C

    2011-06-01

    Full Text Available Chirag G Patel, Li Li, Suzette Girgis, David M Kornhauser, Ernest U Frevert, David W BoultonBristol-Myers Squibb, Princeton, NJ, USABackground: Many medicines, including several cholesterol-lowering agents (eg, lovastatin, simvastatin, antihypertensives (eg, diltiazem, nifedipine, verapamil, and antifungals (eg, ketoconazole are metabolized by and/or inhibit the cytochrome P450 (CYP 3A4 metabolic pathway. These types of medicines are commonly coprescribed to treat comorbidities in patients with type 2 diabetes mellitus (T2DM and the potential for drug-drug interactions of these medicines with new medicines for T2DM must be carefully evaluated.Objective: To investigate the effects of CYP3A4 substrates or inhibitors, simvastatin (substrate, diltiazem (moderate inhibitor, and ketoconazole (strong inhibitor on the pharmacokinetics and safety of saxagliptin, a CYP3A4/5 substrate; and the effects of saxagliptin on these agents in three separate studies.Methods: Healthy subjects were administered saxagliptin 10 mg or 100 mg. Simvastatin, diltiazem extended-release, and ketoconazole doses of 40 mg once daily, 360 mg once daily, and 200 mg twice daily, respectively, were used to determine two-way pharmacokinetic interactions.Results: Coadministration of simvastatin, diltiazem extended-release, or ketoconazole increased mean area under the concentration-time curve values (AUC of saxagliptin by 12%, 109%, and 145%, respectively, versus saxagliptin alone. Mean exposure (AUC of the CYP3A4-generated active metabolite of saxagliptin, 5-hydroxy saxagliptin, decreased with coadministration of simvastatin, diltiazem, and ketoconazole by 2%, 34%, and 88%, respectively. All adverse events were considered mild or moderate in all three studies; there were no serious adverse events or deaths.Conclusion: Saxagliptin, when coadministered with simvastatin, diltiazem extended-release, or ketoconazole, was safe and generally well tolerated in healthy subjects. Clinically

  9. Structure-based drug design, synthesis and biological assays of P. falciparum Atg3-Atg8 protein-protein interaction inhibitors

    Science.gov (United States)

    Villa, Stefania; Legnani, Laura; Colombo, Diego; Gelain, Arianna; Lammi, Carmen; Bongiorno, Daniele; Ilboudo, Denise P.; McGee, Kellen E.; Bosch, Jürgen; Grazioso, Giovanni

    2018-03-01

    The proteins involved in the autophagy (Atg) pathway have recently been considered promising targets for the development of new antimalarial drugs. In particular, inhibitors of the protein-protein interaction (PPI) between Atg3 and Atg8 of Plasmodium falciparum retarded the blood- and liver-stages of parasite growth. In this paper, we used computational techniques to design a new class of peptidomimetics mimicking the Atg3 interaction motif, which were then synthesized by click-chemistry. Surface plasmon resonance has been employed to measure the ability of these compounds to inhibit the Atg3-Atg8 reciprocal protein-protein interaction. Moreover, P. falciparum growth inhibition in red blood cell cultures was evaluated as well as the cyto-toxicity of the compounds.

  10. Modeling Chemical Interaction Profiles: I. Spectral Data-Activity Relationship and Structure-Activity Relationship Models for Inhibitors and Non-inhibitors of Cytochrome P450 CYP3A4 and CYP2D6 Isozymes

    Directory of Open Access Journals (Sweden)

    Richard D. Beger

    2012-03-01

    Full Text Available An interagency collaboration was established to model chemical interactions that may cause adverse health effects when an exposure to a mixture of chemicals occurs. Many of these chemicals—drugs, pesticides, and environmental pollutants—interact at the level of metabolic biotransformations mediated by cytochrome P450 (CYP enzymes. In the present work, spectral data-activity relationship (SDAR and structure-activity relationship (SAR approaches were used to develop machine-learning classifiers of inhibitors and non-inhibitors of the CYP3A4 and CYP2D6 isozymes. The models were built upon 602 reference pharmaceutical compounds whose interactions have been deduced from clinical data, and 100 additional chemicals that were used to evaluate model performance in an external validation (EV test. SDAR is an innovative modeling approach that relies on discriminant analysis applied to binned nuclear magnetic resonance (NMR spectral descriptors. In the present work, both 1D 13C and 1D 15N-NMR spectra were used together in a novel implementation of the SDAR technique. It was found that increasing the binning size of 1D 13C-NMR and 15N-NMR spectra caused an increase in the tenfold cross-validation (CV performance in terms of both the rate of correct classification and sensitivity. The results of SDAR modeling were verified using SAR. For SAR modeling, a decision forest approach involving from 6 to 17 Mold2 descriptors in a tree was used. Average rates of correct classification of SDAR and SAR models in a hundred CV tests were 60% and 61% for CYP3A4, and 62% and 70% for CYP2D6, respectively. The rates of correct classification of SDAR and SAR models in the EV test were 73% and 86% for CYP3A4, and 76% and 90% for CYP2D6, respectively. Thus, both SDAR and SAR methods demonstrated a comparable performance in modeling a large set of structurally diverse data. Based on unique NMR structural descriptors, the new SDAR modeling method complements the existing SAR

  11. Interaction proteins of invertase and invertase inhibitor in cold-stored potato tubers suggested a protein complex underlying post-translational regulation of invertase.

    Science.gov (United States)

    Lin, Yuan; Liu, Jun; Liu, Xun; Ou, Yongbin; Li, Meng; Zhang, Huiling; Song, Botao; Xie, Conghua

    2013-12-01

    The activity of vacuolar invertase (VI) is vital to potato cold-induced sweetening (CIS). A post-translational regulation of VI activity has been proposed which involves invertase inhibitor (VIH), but the mechanism for the interaction between VI and VIH has not been fully understood. To identify the potential partners of VI and VIH, two cDNA libraries were respectively constructed from CIS-resistant wild potato species Solanum berthaultii and CIS-sensitive potato cultivar AC035-01 for the yeast two-hybrid analysis. The StvacINV1 (one of the potato VIs) and StInvInh2B (one of the potato VIHs), previously identified to be associated with potato CIS, were used as baits to screen the two libraries. Through positive selection and sequencing, 27 potential target proteins of StvacINV1 and eight of StInvInh2B were clarified. The Kunitz-type protein inhibitors were captured by StvacINV1 in both libraries and the interaction between them was confirmed by bimolecular fluorescence complementation assay in tobacco cells, reinforcing a fundamental interaction between VI and VIH. Notably, a sucrose non-fermenting-1-related protein kinase 1 was captured by both the baits, suggesting that a protein complex could be necessary for fine turning of the invertase activity. The target proteins clarified in present research provide a route to elucidate the mechanism by which the VI activity can be subtly modulated. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  12. Proposal for novel curcumin derivatives as potent inhibitors against Alzheimer's disease: Ab initio molecular simulations on the specific interactions between amyloid-beta peptide and curcumin

    Science.gov (United States)

    Ota, Shintaro; Fujimori, Mitsuki; Ishimura, Hiromi; Shulga, Sergiy; Kurita, Noriyuki

    2017-10-01

    Accumulation of amyloid-β (Aβ) peptides in a brain is closely related with the pathogenesis of Alzheimer's disease. To suppress the production of Aβ peptides, we propose novel curcumin derivatives and investigate their binding properties with the amyloid precursor protein (APP), using protein-ligand docking as well as ab initio molecular simulations. Our proposed derivative (curcumin XIV) is found to have a large binding energy with APP and interacts strongly with the cleavage site Ala19 by secretase. It is thus expected that curcumin XIV can protect APP from the secretase attack and be a potent inhibitor against the production of Aβ peptides.

  13. Rational Design of a Highly Potent and Selective Peptide Inhibitor of PACE4 by Salt Bridge Interaction with D160 at Position P3.

    Science.gov (United States)

    Dianati, Vahid; Shamloo, Azar; Kwiatkowska, Anna; Desjardins, Roxane; Soldera, Armand; Day, Robert; Dory, Yves L

    2017-08-08

    PACE4, a member of the proprotein convertases (PCs) family of serine proteases, is a validated target for prostate cancer. Our group has developed a potent and selective PACE4 inhibitor: Ac-LLLLRVKR-NH 2 . In seeking for modifications to increase the selectivity of this ligand toward PACE4, we replaced one of its P3 Val methyl groups with a basic group capable of forming a salt bridge with D160 of PACE4. The resulting inhibitor is eight times more potent than the P3 Val parent inhibitor and two times more selective over furin, because the equivalent salt bridge with furin E257 is not optimal. Moreover, the β-branched nature of the new P3 residue favors the extended β-sheet conformation usually associated with substrates of proteases. This work provides new insight for better understanding of β-sheet backbone-backbone interactions between serine proteases and their peptidic ligands. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Structural and biophysical analysis of interactions between cod and human uracil-DNA N-glycosylase (UNG) and UNG inhibitor (Ugi)

    Energy Technology Data Exchange (ETDEWEB)

    Assefa, Netsanet Gizaw [UiT The Arctic University of Norway, 9037 Tromsø (Norway); Niiranen, Laila [UiT The Arctic University of Norway, 9037 Tromsø (Norway); University of Turku, FIN-20014 Turku (Finland); Johnson, Kenneth A.; Leiros, Hanna-Kirsti Schrøder; Smalås, Arne Oskar; Willassen, Nils Peder [UiT The Arctic University of Norway, 9037 Tromsø (Norway); Moe, Elin, E-mail: elin.moe@uit.no [UiT The Arctic University of Norway, 9037 Tromsø (Norway); Universidade Nova de Lisboa, Avenida da Republica (EAN), 2780-157 Oeiras (Portugal)

    2014-08-01

    A structural and biophysical study of the interactions between cod and human uracil-DNA N-glycosylase (UNG) and their inhibitor Ugi is presented. The stronger interaction between cod UNG and Ugi can be explained by a greater positive electrostatic surface potential. Uracil-DNA N-glycosylase from Atlantic cod (cUNG) shows cold-adapted features such as high catalytic efficiency, a low temperature optimum for activity and reduced thermal stability compared with its mesophilic homologue human UNG (hUNG). In order to understand the role of the enzyme–substrate interaction related to the cold-adapted properties, the structure of cUNG in complex with a bacteriophage encoded natural UNG inhibitor (Ugi) has been determined. The interaction has also been analyzed by isothermal titration calorimetry (ITC). The crystal structure of cUNG–Ugi was determined to a resolution of 1.9 Å with eight complexes in the asymmetric unit related through noncrystallographic symmetry. A comparison of the cUNG–Ugi complex with previously determined structures of UNG–Ugi shows that they are very similar, and confirmed the nucleotide-mimicking properties of Ugi. Biophysically, the interaction between cUNG and Ugi is very strong and shows a binding constant (K{sub b}) which is one order of magnitude larger than that for hUNG–Ugi. The binding of both cUNG and hUNG to Ugi was shown to be favoured by both enthalpic and entropic forces; however, the binding of cUNG to Ugi is mainly dominated by enthalpy, while the entropic term is dominant for hUNG. The observed differences in the binding properties may be explained by an overall greater positive electrostatic surface potential in the protein–Ugi interface of cUNG and the slightly more hydrophobic surface of hUNG.

  15. Matrix metalloproteinase-10 (MMP-10) interaction with tissue inhibitors of metalloproteinases TIMP-1 and TIMP-2: binding studies and crystal structure.

    Science.gov (United States)

    Batra, Jyotica; Robinson, Jessica; Soares, Alexei S; Fields, Alan P; Radisky, Derek C; Radisky, Evette S

    2012-05-04

    Matrix metalloproteinase 10 (MMP-10, stromelysin-2) is a secreted metalloproteinase with functions in skeletal development, wound healing, and vascular remodeling; its overexpression is also implicated in lung tumorigenesis and tumor progression. To understand the regulation of MMP-10 by tissue inhibitors of metalloproteinases (TIMPs), we have assessed equilibrium inhibition constants (K(i)) of putative physiological inhibitors TIMP-1 and TIMP-2 for the active catalytic domain of human MMP-10 (MMP-10cd) using multiple kinetic approaches. We find that TIMP-1 inhibits the MMP-10cd with a K(i) of 1.1 × 10(-9) M; this interaction is 10-fold weaker than the inhibition of the similar MMP-3 (stromelysin-1) catalytic domain (MMP-3cd) by TIMP-1. TIMP-2 inhibits the MMP-10cd with a K(i) of 5.8 × 10(-9) M, which is again 10-fold weaker than the inhibition of MMP-3cd by this inhibitor (K(i) = 5.5 × 10(-10) M). We solved the x-ray crystal structure of TIMP-1 bound to the MMP-10cd at 1.9 Å resolution; the structure was solved by molecular replacement and refined with an R-factor of 0.215 (R(free) = 0.266). Comparing our structure of MMP-10cd·TIMP-1 with the previously solved structure of MMP-3cd·TIMP-1 (Protein Data Bank entry 1UEA), we see substantial differences at the binding interface that provide insight into the differential binding of stromelysin family members to TIMP-1. This structural information may ultimately assist in the design of more selective TIMP-based inhibitors tailored for specificity toward individual members of the stromelysin family, with potential therapeutic applications.

  16. Biochemistry and biophysics of HIV-1 gp41 - membrane interactions and implications for HIV-1 envelope protein mediated viral-cell fusion and fusion inhibitor design.

    Science.gov (United States)

    Cai, Lifeng; Gochin, Miriam; Liu, Keliang

    2011-12-01

    Human immunodeficiency virus type 1 (HIV-1), the pathogen of acquired immunodeficiency syndrome (AIDS), causes ~2 millions death every year and still defies an effective vaccine. HIV-1 infects host cells through envelope protein - mediated virus-cell fusion. The transmembrane subunit of envelope protein, gp41, is the molecular machinery which facilitates fusion. Its ectodomain contains several distinguishing functional domains, fusion peptide (FP), Nterminal heptad repeat (NHR), C-terminal heptad repeat (CHR) and membrane proximal extracellular region (MPER). During the fusion process, FP inserts into the host cell membrane, and an extended gp41 prehairpin conformation bridges the viral and cell membranes through MPER and FP respectively. Subsequent conformational change of the unstable prehairpin results in a coiled-coil 6-helix bundle (6HB) structure formed between NHR and CHR. The energetics of 6HB formation drives membrane apposition and fusion. Drugs targeting gp41 functional domains to prevent 6HB formation inhibit HIV-1 infection. T20 (enfuvirtide, Fuzeon) was approved by the US FDA in 2003 as the first fusion inhibitor. It is a 36-residue peptide from the gp41 CHR, and it inhibits 6HB formation by targeting NHR and lipids. Development of new fusion inhibitors, especially small molecule drugs, is encouraged to overcome the shortcomings of T20 as a peptide drug. Hydrophobic characteristics and membrane association are critical for gp41 function and mechanism of action. Research in gp41-membrane interactions, using peptides corresponding to specific functional domains, or constructs including several interactive domains, are reviewed here to get a better understanding of gp41 mediated virus-cell fusion that can inform or guide the design of new HIV-1 fusion inhibitors.

  17. A Biochemical/Biophysical Assay Dyad for HTS-Compatible Triaging of Inhibitors of the HIV-1 Nef/Hck SH3 Interaction

    KAUST Repository

    Breuer, Sebastian

    2013-07-26

    The current treatment regimens for HIV include over 20 anti-retrovirals. However, adverse drug effects and the emergence of drug resistance necessitates the continued improvement of the existing drug classes as well as the development of novel drugs that target as yet therapeutically unexploited viral and cellular pathways. Here we demonstrate a strategy for the discovery of protein-protein interaction inhibitors of the viral pathogenicity factor HIV-1 Nef and its interaction with the host factor SH3. A combination of a time-resolved fluorescence resonance energy resonance energy transfer-based assay and a label-free resonant waveguide grating-based assay was optimized for high-throughput screening formats.

  18. The Effect of Gamma radiation, microwave radiation, their interaction and storage on chemical composition, antinutritional factors and the activities of trypsin inhibitor and lipoxygenase of soybean seeds

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Rahim, E A; Abdel-Fatah, O M [Dept. of Biochem., Faculty of Agric., Cairo University. (Egypt); El-Adawy, M; Badea, M Y [Food Technol. Dept., National Center for Research and Radiation Technol., Atomic Energy Authority (Egypt)

    2000-07-01

    The effect of gamma radiation, microwave radiation, interaction between them; and storage of radiated soybean seeds were investigated to find out the best treatment which had to the maximum reduction of antinutrional factors (Trypsin inhibitor and lipoxygenase activities) without significant effect on the chemical constituents. The gamma rays was used at three doses of 2.5, 5.0 and 8.0 kGy, microwave radiation was at 70 level power for 2 and 4 min; and the storage of seeds was at temperature, R.H. 50-55% for six months. The data revealed that, effects of interaction treatments were more effective than the treatment with microwave or gamma radiation alone.

  19. The Effect of Gamma radiation, microwave radiation, their interaction and storage on chemical composition, antinutritional factors and the activities of trypsin inhibitor and lipoxygenase of soybean seeds

    International Nuclear Information System (INIS)

    Abdel-Rahim, E.A.; Abdel-Fatah, O.M.; El-Adawy, M.; Badea, M.Y.

    2000-01-01

    The effect of gamma radiation, microwave radiation, interaction between them; and storage of radiated soybean seeds were investigated to find out the best treatment which had to the maximum reduction of antinutrional factors (Trypsin inhibitor and lipoxygenase activities) without significant effect on the chemical constituents. The gamma rays was used at three doses of 2.5, 5.0 and 8.0 kGy, microwave radiation was at 70 level power for 2 and 4 min; and the storage of seeds was at temperature, R.H. 50-55% for six months. The data revealed that, effects of interaction treatments were more effective than the treatment with microwave or gamma radiation alone

  20. A Biochemical/Biophysical Assay Dyad for HTS-Compatible Triaging of Inhibitors of the HIV-1 Nef/Hck SH3 Interaction

    KAUST Repository

    Breuer, Sebastian; Espinola, Sheryll; Morelli, Xavier; Torbett, Bruce E; Arold, Stefan T.; Engels, Ingo H

    2013-01-01

    The current treatment regimens for HIV include over 20 anti-retrovirals. However, adverse drug effects and the emergence of drug resistance necessitates the continued improvement of the existing drug classes as well as the development of novel drugs that target as yet therapeutically unexploited viral and cellular pathways. Here we demonstrate a strategy for the discovery of protein-protein interaction inhibitors of the viral pathogenicity factor HIV-1 Nef and its interaction with the host factor SH3. A combination of a time-resolved fluorescence resonance energy resonance energy transfer-based assay and a label-free resonant waveguide grating-based assay was optimized for high-throughput screening formats.

  1. Identification of Tight-Binding Plasmepsin II and Falcipain 2 Inhibitors in Aqueous Extracts of Marine Invertebrates by the Combination of Enzymatic and Interaction-Based Assays

    Science.gov (United States)

    Salas-Sarduy, Emir; Guerra, Yasel; Covaleda Cortés, Giovanni; Avilés, Francesc Xavier; Chávez Planes, María A.

    2017-01-01

    Natural products from marine origin constitute a very promising and underexplored source of interesting compounds for modern biotechnological and pharmaceutical industries. However, their evaluation is quite challenging and requires specifically designed assays to reliably identify the compounds of interest in a highly heterogeneous and interfering context. In the present study, we describe a general strategy for the confident identification of tight-binding protease inhibitors in the aqueous extracts of 62 Cuban marine invertebrates, using Plasmodium falciparum hemoglobinases Plasmepsin II and Falcipain 2 as model enzymes. To this end, we first developed a screening strategy that combined enzymatic with interaction-based assays and then validated screening conditions using five reference extracts. Interferences were evaluated and minimized. The results from the massive screening of such extracts, the validation of several hits by a variety of interaction-based assays and the purification and functional characterization of PhPI, a multifunctional and reversible tight-binding inhibitor for Plasmepsin II and Falcipain 2 from the gorgonian Plexaura homomalla, are presented. PMID:28430158

  2. Molecular interaction studies of acetylcholinesterase with potential acetylcholinesterase inhibitors from the root of Rhodiola crenulata using molecular docking and isothermal titration calorimetry methods.

    Science.gov (United States)

    Li, Fa-Jie; Liu, Yuan; Yuan, Yuan; Yang, Bin; Liu, Zhen-Ming; Huang, Lu-Qi

    2017-11-01

    (-)-Epicatechin gallate ((-)-ECG), 1,2,3,4,6-O-pentagalloylglucose (PGG), rhodionin, herbacetin and rhodiosin isolated from the root of Rhodiola crenulata exhibited potent, dose-dependent inhibitory effects on acetylcholinesterase (AChE) with IC 50 ranged from 57.50±5.83 to 2.43±0.34μg/mL. With the aim of explaining the differences in activity of these active ingredients and clarifying how they inhibit AChE, the AChE-inhibitor interactions were further explored using molecular docking and isothermal titration calorimetry (ITC) methods in the present study. Molecular docking studies revealed that all compounds except PGG showed binding energy values ranging from -10.30 to -8.00kcal/mol while the binding energy of galantamine, a known AChE inhibitor, was -9.53kcal/mol; they inhibited the AChE by binding into the ligand pocket with the similar binding pattern to that of galantamine by interacting with Glu199 of AChE. Inhibition constant of these active ingredients had a positive correlation with binding energy. The interaction between AChE and PGG was further evaluated with the ITC method and the results indicated that the PGG-AChE interaction was relevant to AChE concentration. The results revealed a possible mechanism for the AChE inhibition activity of these bioactive ingredients, which may provide some help in lead compounds optimization in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Identification of danthron as an isoform-specific inhibitor of HEME OXYGENASE-1/cytochrome P450 reductase interaction with anti-tumor activity.

    Science.gov (United States)

    Chou, Yi-Tai; Hsu, Fu-Fei; Hu, Dun-Yao; Chen, Ying-Chih; Hsu, Yuan-Hao; Hsu, John T-A; Chau, Lee-Young

    2018-01-23

    Heme oxygenase (HO) catalyzes NADPH-dependent degradation of heme to liberate iron, carbon monoxide and biliverdin. The interaction between HO and cytochrome P450 reductase (CPR), an electron donor, is essential for HO activity. HO-1 is a stress-inducible isoform whereas HO-2 is constitutively expressed. HO-1 induction is commonly seen in cancers and impacts disease progression, supporting the possibility of targeting HO-1 for cancer therapy. We employed a cell-based bioluminescence resonance energy transfer assay to screen compounds with ability to inhibit HO-1/CPR interaction. The effect of the identified compound on HO-1/CPR interaction was confirmed by pull down assay. Moreover, the anti-tumorigenic activity of the identified compound on HO-1-enhanced tumor growth and migration was assessed by trypan blue exclusion method and wound healing assay. Danthron was identified as an effective small molecule able to interfere with the interaction between HO-1 and CPR but not HO-2 and CPR. Additional experiments with structural analogues of danthron revealed that the positions of hydroxyl moieties significantly affected the potency of inhibition on HO-1/CPR interaction. Pull-down assay confirmed that danthron inhibited the interaction of CPR with HO-1 but not HO-2. Danthron suppressed growth and migration of HeLa cells with stable HO-1 overexpression but not mock cells. In contrast, anthrarufin, a structural analog with no ability to interfere HO-1/CPR interaction, exhibited no significant effect on HO-1-overexpressing HeLa cells. These findings demonstrate that danthron is an isoform-specific inhibitor for HO-1/CPR interaction and may serve as a lead compound for novel anticancer drug.

  4. Interaction of new kinase inhibitors cabozantinib and tofacitinib with human serum alpha-1 acid glycoprotein. A comprehensive spectroscopic and molecular Docking approach

    Science.gov (United States)

    Ajmal, Mohammad Rehan; Abdelhameed, Ali Saber; Alam, Parvez; Khan, Rizwan Hasan

    2016-04-01

    In the current study we have investigated the interaction of newly approved kinase inhibitors namely Cabozantinib (CBZ) and Tofacitinib (TFB) with human Alpha-1 acid glycoprotein (AAG) under simulated physiological conditions using fluorescence quenching measurements, circular dichroism, dynamic light scattering and molecular docking methods. CBZ and TFB binds to AAG with significant affinity and the calculated binding constant for the drugs lie in the order of 104. With the increase in temperature the binding constant values decreased for both CBZ and TFB. The fluorescence resonance energy transfer (FRET) from AAG to CBZ and TFB suggested the fluorescence intensity of AAG was quenched by the two studied drugs via the formation of a non-fluorescent complex in the static manner. The molecular distance r value calculated from FRET is around 2 nm for both drugs, fluorescence spectroscopy data was employed for the study of thermodynamic parameters, standard Gibbs free energy change at 300K was calculated as - 5.234 kcal mol- 1 for CBZ-AAG interaction and - 6.237 kcal mol- 1 for TFB-AAG interaction, standard enthalpy change and standard entropy change for CBZ-AAG interaction are - 9.553 kcal mol- 1 and - 14.618 cal mol- 1K- 1 respectively while for AAG-TFB interaction, standard enthalpy and standard entropy change was calculated as 4.019 kcal mol- 1 and 7.206 cal mol- 1K- 1 respectively. Protein binding of the two drugs caused the tertiary structure alterations. Dynamic light scattering measurements demonstrated the reduction in the hydrodynamic radii of the protein. Furthermore molecular docking results suggested the Hydrophobic interaction and hydrogen bonding were the interactive forces in the binding process of CBZ to AAG while in case of TFB only hydrophobic interactions were found to be involved, overlap of the binding site for two studied drugs on the AAG molecule was revealed by docking results.

  5. [How aliphatic alcohols and ph affect reactional capability of the horse blood serum cholinesterase at its interaction with organophosphorus inhibitors].

    Science.gov (United States)

    Basova, N E; Kormilitsin, B N; Perchenok, A Iu; Rozengart, E V; Saakov, V S; Suvorov, A A

    2013-01-01

    There was studied action of aliphatic alcohols (ethanol, propanol, isopropanol, n-butanol, isobutanol, secbutanol, tretbetanol) and pH on various kinds of reactional capability the serum cholinesterase. At the alcohols-affected inhibition of the cholinesterase hydrolytic activity, the determining role was played not the total number carbon atoms in the alcohol molecule, but by the "effective length" of the carbohydrate chain. The fact that the presence of alcohols did not affect parameters of the reverse cholinesterase inhibition with onium ions tetramethylammonium and choline allows suggesting the absence of effect solvents on specific acetylcholine sorption in the enzyme active center. With aid of two rows of hydrophobic organophosphorus inhibitors (OPI), we have managed to estimate both the degree and the character itself of the modifying action of alcohols and pH on the process of irreversible inhibition of serum cholinesterase.

  6. Interactions of a potent cyclic peptide inhibitor with the light chain of botulinum neurotoxin A: Insights from X-ray crystallography.

    Science.gov (United States)

    Kumaran, Desigan; Adler, Michael; Levit, Matthew; Krebs, Michael; Sweeney, Richard; Swaminathan, Subramanyam

    2015-11-15

    The seven antigenically distinct serotypes (A-G) of botulinum neurotoxin (BoNT) are responsible for the deadly disease botulism. BoNT serotype A (BoNT/A) exerts its lethal action by cleaving the SNARE protein SNAP-25, leading to inhibition of neurotransmitter release, flaccid paralysis and autonomic dysfunction. BoNTs are dichain proteins consisting of a ∼ 100 kDa heavy chain and a ∼ 50 kDa light chain; the former is responsible for neurospecific binding, internalization and translocation, and the latter for cleavage of neuronal SNARE proteins. Because of their extreme toxicity and history of weaponization, the BoNTs are regarded as potential biowarfare/bioterrorism agents. No post-symptomatic therapeutic interventions are available for BoNT intoxication other than intensive care; therefore it is imperative to develop specific antidotes against this neurotoxin. To this end, a cyclic peptide inhibitor (CPI-1) was evaluated in a FRET assay for its ability to inhibit BoNT/A light chain (Balc). CPI was found to be highly potent, exhibiting a Ki of 12.3 nM with full-length Balc448 and 39.2 nM using a truncated crystallizable form of the light chain (Balc424). Cocrystallization studies revealed that in the Balc424-CPI-1 complex, the inhibitor adopts a helical conformation, occupies a high percentage of the active site cavity and interacts in an amphipathic manner with critical active site residues. The data suggest that CPI-1 prevents SNAP-25 from accessing the Balc active site by blocking both the substrate binding path at the surface and the Zn(2+) binding region involved in catalysis. This differs from linear peptide inhibitors described to date which block only the latter. Published by Elsevier Ltd.

  7. Development of Nano-Liposomal Formulations of Epidermal Growth Factor Receptor Inhibitors and their Pharmacological Interactions on Drug-Sensitive and Drug-Resistant Cancer Cell Lines

    Science.gov (United States)

    Trummer, Brian J.

    , due to leaky tumor vasculature and the resulting Enhanced Permeability and Retention (EPR) phenomenon. In Chapter 2 we report that both gefitinib and the structurally similar EGFR inhibitor erlotinib display environment-dependent fluorescence properties. Peak excitation was 345 nm, and the emission peak ranged from 365 to 476 nm, depending upon the polarity of the environment and physical state of the drug. The fluorescence was negligible in aqueous solution, but intense in organic solvents or membrane bilayers. The environment-sensitive fluorescence properties of these drugs enabled rapid evaluation of numerous parameters affecting liposomal drug incorporation and performance. Up to 4-6 mol% of gefitinib could be incorporated in the liposome bilayer, based upon hydrophobic interactions with membrane bilayers. In contrast, 40-60 mol% could be loaded into the aqueous core of pre-formed liposomes at high efficiency, using a remote loading procedure. A stable formulation consisting of distearoylphosphatidylcholine: polyethylene glycol-distereoylphosphatidylethanolamine: cholesterol (DSPC:PEGDSPE:Chol, 9:1:5 mol:mol:mol) and containing drug at 50-60 mol% gefitinib (L-GEF) showed minimal leakage in serum-containing medium over 24 h at 37°C, which should be sufficient to improve biodistribution in vivo. Chapter 3 investigated the pharmacological activity of liposome-encapsulated gefitinib, alone and in combination with several prevalent anticancer agents. Experiments with MCF7 breast cancer cell lines demonstrated that liposome encapsulated gefitinib formulation (L-GEF) had a 2-fold higher IC50 (concentration of drug resulting in half-maximal growth inhibition) than free gefitinib. Lower in vitro potency would be consistent with delayed drug release from the carrier. Therapeutic effects were investigated in combination with the cytotoxic agents paclitaxel and doxorubicin. The drug-resistant MCF7R cell line was 23-fold more resistant to paclitaxel than the parental, drug

  8. A strategy for early-risk predictions of clinical drug-drug interactions involving the GastroPlusTM DDI module for time-dependent CYP inhibitors.

    Science.gov (United States)

    Sohlenius-Sternbeck, Anna-Karin; Meyerson, Gabrielle; Hagbjörk, Ann-Louise; Juric, Sanja; Terelius, Ylva

    2018-04-01

    1. A set of reference compounds for time-dependent inhibition (TDI) of cytochrome P450 with available literature data for k inact and K I was used to predict clinical implications using the GastroPlus TM software. Comparisons were made to in vivo literature interaction data. 2. The predicted AUC ratios (AUC +inhibitor /AUC control ) could be compared with the observed ratios from literature for all compounds with detailed information about in vivo administration, pharmacokinetics and in vivo interactions (N = 21). For this dataset, the difference between predicted and observed AUC ratios for interactions with midazolam was within twofold for all compounds except one (telaprevir, for which non-CYP-mediated metabolism likely plays a role after multiple dosing). 3. The sensitivity, specificity and accuracy of the GastroPlus TM predictions using a binary classification as no-to-weak interaction versus moderate-to-strong interaction for all compounds with available in vivo interaction data, were 80%, 82% and 81%, respectively (N = 31). 4. As a result of our evaluations of the DDI module in GastroPlus TM , we have implemented an early TDI risk assessment decision tree for our drug discovery projects involving in vitro screening and early GastroPlus TM predictions. Shifted IC 50 values are determined and k inact /K I estimated (by using a regression line established with in house-shifted IC 50 values and literature k inact /K I ratios), followed by GastroPlus TM predictions.

  9. Polycyclic phloroglucinols as PTP1B inhibitors from Hypericum longistylum: Structures, PTP1B inhibitory activities, and interactions with PTP1B.

    Science.gov (United States)

    Cao, Xiangrong; Yang, Xueyuan; Wang, Peixia; Liang, Yue; Liu, Feng; Tuerhong, Muhetaer; Jin, Da-Qing; Xu, Jing; Lee, Dongho; Ohizumi, Yasushi; Guo, Yuanqiang

    2017-12-01

    Protein tyrosine phosphatase 1B (PTP1B) has been regarded asa target for the research and development of new drugs to treat type II diabetes and PTP1B inhibitors are potential lead compounds for this type of new drugs. A phytochemical investigation to obtain new PTP1B inhibitors resulted in the isolation of four new phloroglucinols, longistyliones A-D (1-4) from the aerial parts of Hypericum longistylum. The structures of 1-4 were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis, and the absolute configurations of these compounds were established by comparing their experimental electronic circular dichroism (ECD) spectra with those calculated by the time-dependent density functional theory method. Compounds 1-4 possess a rare polycyclic phloroglucinol skeleton. The following biological evaluation revealed that all of the compounds showed PTP1B inhibitory effects. The further molecular docking studies indicated the strong interactions between these bioactive compounds with the PTP1B protein, which revealed the possible mechanism of PTP1B inhibition of bioactive compounds. All of the results implied that these compounds are potentially useful for the treatment of type II diabetes. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Proteochemometric Modeling of the Interaction Space of Carbonic Anhydrase and its Inhibitors: An Assessment of Structure-based and Sequence-based Descriptors.

    Science.gov (United States)

    Rasti, Behnam; Namazi, Mohsen; Karimi-Jafari, M H; Ghasemi, Jahan B

    2017-04-01

    Due to its physiological and clinical roles, carbonic anhydrase (CA) is one of the most interesting case studies. There are different classes of CAinhibitors including sulfonamides, polyamines, coumarins and dithiocarbamates (DTCs). However, many of them hardly act as a selective inhibitor against a specific isoform. Therefore, finding highly selective inhibitors for different isoforms of CA is still an ongoing project. Proteochemometrics modeling (PCM) is able to model the bioactivity of multiple compounds against different isoforms of a protein. Therefore, it would be extremely applicable when investigating the selectivity of different ligands towards different receptors. Given the facts, we applied PCM to investigate the interaction space and structural properties that lead to the selective inhibition of CA isoforms by some dithiocarbamates. Our models have provided interesting structural information that can be considered to design compounds capable of inhibiting different isoforms of CA in an improved selective manner. Validity and predictivity of the models were confirmed by both internal and external validation methods; while Y-scrambling approach was applied to assess the robustness of the models. To prove the reliability and the applicability of our findings, we showed how ligands-receptors selectivity can be affected by removing any of these critical findings from the modeling process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Underlying mechanism of drug-drug interaction between pioglitazone and gemfibrozil: Gemfibrozil acyl-glucuronide is a mechanism-based inhibitor of CYP2C8.

    Science.gov (United States)

    Takagi, Motoi; Sakamoto, Masaya; Itoh, Tomoo; Fujiwara, Ryoichi

    2015-08-01

    While co-administered gemfibrozil can increase the area under the concentration/time curve (AUC) of pioglitazone more than 3-fold, the underlying mechanism of the drug-drug interaction between gemfibrozil and pioglitazone has not been fully understood. In the present study, gemfibrozil preincubation time-dependently inhibited the metabolism of pioglitazone in the cytochrome P450 (CYP)- and UDP-glucuronosyltransferase (UGT)-activated human liver microsomes. We estimated the kinact and K'app values, which are the maximum inactivation rate constant and the apparent dissociation constant, of gemfibrozil to be 0.071 min(-1) and 57.3 μM, respectively. In this study, the kobs, in vivo value was defined as a parameter that indicates the potency of the mechanism-based inhibitory effect at the blood drug concentration in vivo. The kobs, in vivo values of potent mechanism-based inhibitors, clarithromycin and erythromycin, were estimated to be 0.0096 min(-1) and 0.0051 min(-1), respectively. The kobs, in vivo value of gemfibrozil was 0.0060 min(-1), which was comparable to those of clarithromycin and erythromycin, suggesting that gemfibrozil could be a mechanism-based inhibitor as potent as clarithromycin and erythromycin in vivo. Copyright © 2015 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.

  12. Alteration of RNA splicing by small molecule inhibitors of the interaction between NHP2L1 and U4

    Science.gov (United States)

    Diouf, Barthelemy; Lin, Wenwei; Goktug, Asli; Grace, Christy R. R.; Waddell, Michael Brett; Bao, Ju; Shao, Youming; Heath, Richard J.; Zheng, Jie J.; Shelat, Anang A.; Relling, Mary V.; Chen, Taosheng; Evans, William E.

    2018-01-01

    Splicing is an important eukaryotic mechanism for expanding the transcriptome and proteome, influencing a number of biological processes. Understanding its regulation and identifying small molecules that modulate this process remains a challenge. We developed an assay based on time-resolved FRET (TR-FRET) to detect the interaction between the protein NHP2L1 and U4 RNA, which are two key components of the spliceosome. We used this assay to identify small molecules that interfere with this interaction in a high-throughput screening (HTS) campaign. Topotecan and other camptothecin derivatives were among the top hits. We confirmed that topotecan disrupts the interaction between NHP2L1 and U4 by binding to U4 and inhibits RNA splicing. Our data reveal new functions of known drugs which could facilitate the development of therapeutic strategies to modify splicing and alter gene function. PMID:28985478

  13. The Sam-Sam interaction between Ship2 and the EphA2 receptor: design and analysis of peptide inhibitors.

    Science.gov (United States)

    Mercurio, Flavia Anna; Di Natale, Concetta; Pirone, Luciano; Iannitti, Roberta; Marasco, Daniela; Pedone, Emilia Maria; Palumbo, Rosanna; Leone, Marilisa

    2017-12-12

    The lipid phosphatase Ship2 represents a drug discovery target for the treatment of different diseases, including cancer. Its C-terminal sterile alpha motif domain (Ship2-Sam) associates with the Sam domain from the EphA2 receptor (EphA2-Sam). This interaction is expected to mainly induce pro-oncogenic effects in cells therefore, inhibition of the Ship2-Sam/EphA2-Sam complex may represent an innovative route to discover anti-cancer therapeutics. In the present work, we designed and analyzed several peptide sequences encompassing the interaction interface of EphA2-Sam for Ship2-Sam. Peptide conformational analyses and interaction assays with Ship2-Sam conducted through diverse techniques (CD, NMR, SPR and MST), identified a positively charged penta-amino acid native motif in EphA2-Sam, that once repeated three times in tandem, binds Ship2-Sam. NMR experiments show that the peptide targets the negatively charged binding site of Ship2-Sam for EphA2-Sam. Preliminary in vitro cell-based assays indicate that -at 50 µM concentration- it induces necrosis of PC-3 prostate cancer cells with more cytotoxic effect on cancer cells than on normal dermal fibroblasts. This work represents a pioneering study that opens further opportunities for the development of inhibitors of the Ship2-Sam/EphA2-Sam complex for therapeutic applications.

  14. Toward the Discovery of a Novel Class of YAP–TEAD Interaction Inhibitors by Virtual Screening Approach Targeting YAP–TEAD Protein–Protein Interface

    Directory of Open Access Journals (Sweden)

    Floriane Gibault

    2018-05-01

    Full Text Available Intrinsically disordered protein YAP (yes-associated protein interacts with TEADs transcriptional factors family (transcriptional enhancer associated domain creating three interfaces. Interface 3, between the Ω-loop of YAP and a shallow pocket of TEAD was identified as the most important TEAD zone for YAP-TEAD interaction. Using the first X-ray structure of the hYAP50–71-hTEAD1209–426 complex (PDB 3KYS published in 2010, a protein-protein interaction inhibitors-enriched library (175,000 chemical compounds was screened against this hydrophobic pocket of TEAD. Four different chemical families have been identified and evaluated using biophysical techniques (thermal shift assay, microscale thermophoresis and in cellulo assays (luciferase activity in transfected HEK293 cells, RTqPCR in MDA-MB231 cells. A first promising hit with micromolar inhibition in the luciferase gene reporter assay was discovered. This hit also decreased mRNA levels of TEAD target genes.

  15. Variation in HIV-1 R5 macrophage-tropism correlates with sensitivity to reagents that block envelope: CD4 interactions but not with sensitivity to other entry inhibitors

    Directory of Open Access Journals (Sweden)

    Simmonds Peter

    2008-01-01

    Full Text Available Abstract Background HIV-1 R5 viruses cause most of the AIDS cases worldwide and are preferentially transmitted compared to CXCR4-using viruses. Furthermore, R5 viruses vary extensively in capacity to infect macrophages and highly macrophage-tropic variants are frequently identified in the brains of patients with dementia. Here, we investigated the sensitivity of R5 envelopes to a range of inhibitors and antibodies that block HIV entry. We studied a large panel of R5 envelopes, derived by PCR amplification without culture from brain, lymph node, blood and semen. These R5 envelopes conferred a wide range of macrophage tropism and included highly macrophage-tropic variants from brain and non-macrophage-tropic variants from lymph node. Results R5 macrophage-tropism correlated with sensitivity to inhibition by reagents that inhibited gp120:CD4 interactions. Thus, increasing macrophage-tropism was associated with increased sensitivity to soluble CD4 and to IgG-CD4 (PRO 542, but with increased resistance to the anti-CD4 monoclonal antibody (mab, Q4120. These observations were highly significant and are consistent with an increased affinity of envelope for CD4 for macrophage-tropic envelopes. No overall correlations were noted between R5 macrophage-tropism and sensitivity to CCR5 antagonists or to gp41 specific reagents. Intriguingly, there was a relationship between increasing macrophage-tropism and increased sensitivity to the CD4 binding site mab, b12, but decreased sensitivity to 2G12, a mab that binds a glycan complex on gp120. Conclusion Variation in R5 macrophage-tropism is caused by envelope variation that predominantly influences sensitivity to reagents that block gp120:CD4 interactions. Such variation has important implications for therapy using viral entry inhibitors and for the design of envelope antigens for vaccines.

  16. The battle in the apoplast: further insights into the roles of proteases and their inhibitors in plant-pathogen interactions

    Directory of Open Access Journals (Sweden)

    Mansoor eKarimi Jashni

    2015-08-01

    Full Text Available Upon host penetration, fungal pathogens secrete a plethora of effectors to promote disease, including proteases that degrade plant antimicrobial proteins, and protease inhibitors (PIs that inhibit plant proteases with antimicrobial activity. Conversely, plants secrete proteases and PIs to protect themselves against pathogens or to mediate recognition of pathogen proteases and PIs, which leads to induction of defense responses. Many examples of proteases and PIs mediating effector-triggered immunity in host plants have been reported in the literature, but little is known about their role in compromising basal defense responses induced by microbe-associated molecular patterns. Recently, several reports appeared in literature on secreted fungal proteases that modify or degrade pathogenesis-related proteins, including plant chitinases or PIs that compromise their activities. This prompted us to review the recent advances on proteases and PIs involved in fungal virulence and plant defense. Proteases and PIs from plants and their fungal pathogens play an important role in the arms race between plants and pathogens, which has resulted in co-evolutionary diversification and adaptation shaping pathogen lifestyles.

  17. Pharmacokinetic interaction study of sulphasalazine in healthy subjects and the impact of curcumin as an in vivo inhibitor of BCRP

    Science.gov (United States)

    Kusuhara, Hiroyuki; Furuie, Hidetoshi; Inano, Akihiro; Sunagawa, Akihiro; Yamada, Saiko; Wu, Chunyong; Fukizawa, Shinya; Morimoto, Nozomi; Ieiri, Ichiro; Morishita, Mariko; Sumita, Kiminobu; Mayahara, Hiroshi; Fujita, Takuya; Maeda, Kazuya; Sugiyama, Yuichi

    2012-01-01

    BACKGROUND AND PURPOSE An ATP-binding cassette (ABC) transporter, breast cancer resistance protein (BCRP)/ABCG2, limits oral bioavailability of sulphasalazine. Here we examined the effect of curcumin, the principal curcuminoid of turmeric, on oral bioavailability of microdoses and therapeutic doses of sulphasalazine in humans. EXPERIMENTAL APPROACH Effects of curcumin were measured on the ATP-dependent sulphasalazine uptake by hBCRP-expressing membrane vesicles and on oral bioavailability of sulphasalazine in wild-type and Bcrp(–/–) mice. Eight healthy Japanese subjects received an oral dose of sulphasalazine suspension (100 µg) or tablets (2 g) alone or after curcumin tablets (2 g). Uptake of sulphasalazine was studied in HEK293 cells transfected with the influx transporter (OATP)2B1. KEY RESULTS Curcumin was a potent hBCRP inhibitor in vitro (Ki 0.70 ± 0.41 µM). Curcumin increased the area under the curve (AUC)0–8 of plasma sulphasalazine eightfold in wild-type mice at 300 and 400 mg·kg−1, but not in Bcrp(–/–) mice. Curcumin increased AUC0–24 of plasma sulphasalazine 2.0-fold at microdoses and 3.2-fold at therapeutic doses in humans. Non-linearity of the dose–exposure relationship was observed between microdoses and therapeutic doses of sulphasalazine. Sulphasalazine was a substrate for OATP2B1 (Km 1.7 ± 0.3 µM). Its linear index (dose/Km) at the therapeutic dose was high and may saturate OATP2B1. CONCLUSIONS AND IMPLICATIONS Curcumin can be used to investigate effects of BCRP on oral bioavailability of drugs in humans. Besides the limited dissolution, OATP2B1 saturation is a possible mechanism underlying non-linearity in the dose–exposure relationship of sulphasalazine. PMID:22300367

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

    Science.gov (United States)

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

    2017-06-01

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

  19. Hydroxymethylglutaryl-CoA Reductase Inhibitors in Older Persons with Acute Myocardial Infarction: Evidence for an Age–Statin Interaction

    Science.gov (United States)

    Foody, JoAnne Micale; Rathore, Saif S.; Galusha, Deron; Masoudi, Frederick A.; Havranek, Edward P.; Radford, Martha J.; Krumholz, Harlan M.

    2009-01-01

    OBJECTIVES To characterize the relationship between hydroxymethylglutaryl-CoA reductase inhibitors (statins) and outcomes in older persons with acute myocardial infarction (AMI). DESIGN Observational study. SETTING Acute care hospitals in the United States from April 1998 to June 2001. PARTICIPANTS Medicare patients aged 65 and older with a principal discharge diagnosis of AMI (N = 65,020) who did and did not receive a discharge prescription for statins. MEASUREMENTS The primary outcome of interest was all-cause mortality at 3 years after discharge. RESULTS Of 23,013 patients with AMI assessed, 5,513 (24.0%) were receiving a statin at discharge. Nearly 40% of eligible patients (n =8,452) were aged 80 and older, of whom 1,310 (15.5%) were receiving a statin at discharge. In a multivariable model taking into account demographic, clinical, physician and hospital characteristics, and propensity score, discharge statin therapy was associated with significantly lower 3-year mortality (hazard ratio (HR) =0.89 (95% confidence interval (CI) =0.83–0.96)). In an analysis stratified by age, discharge statins were associated with lower mortality in patients younger than 80 (HR =0.84, 95% CI =0.76–0.92) but not in those aged 80 and older (HR =0.97, 95% CI =0.87–1.09). CONCLUSION Statin therapy is associated with lower mortality in older patients with AMI younger than 80 but not in those aged 80 and older, as a group. This finding questions whether statin efficacy data in younger patients can be broadly applied to the very old and indicates the need for further study of this group. PMID:16551308

  20. Analysis of the Interaction between Clopidogrel, Aspirin, and Proton Pump Inhibitors Using the FDA Adverse Event Reporting System Database.

    Science.gov (United States)

    Suzuki, Yukiya; Suzuki, Honami; Umetsu, Ryogo; Uranishi, Hiroaki; Abe, Junko; Nishibata, Yuri; Sekiya, Yasuaki; Miyamura, Nobuteru; Hara, Hideaki; Tsuchiya, Teruo; Kinosada, Yasutomi; Nakamura, Mitsuhiro

    2015-01-01

    Clopidogrel is an antiplatelet agent widely used in combination with aspirin to limit the occurrence of cardiovascular (embolic/thrombotic) events. Consensus guidelines recommend proton pump inhibitors (PPIs) as a gastrointestinal (GI) prophylactic measure for all patients receiving dual antiplatelet therapy with clopidogrel and aspirin. The objective of this study was to analyze the effect of the simultaneous use of clopidogrel, aspirin, and PPIs on hemorrhagic and embolic/thrombotic events using the U.S. Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database. Reports of hemorrhagic and embolic/thrombotic events between 2004 and 2013 were analyzed with a reporting odds ratio (ROR) algorithm and logistic regression methods. The Medical Dictionary for Regulatory Activities Preferred Terms was used to identify such events. Regarding hemorrhagic events, the adjusted RORs of the concomitant use of aspirin and clopidogrel and those of PPIs prescribed with aspirin and clopidogrel were 4.40 (95% confidence interval [CI], 4.02-4.81) and 3.40 (95% CI, 2.84-4.06), respectively. For embolic/thrombotic events, the adjusted RORs of the concomitant use of aspirin and clopidogrel and those of PPIs prescribed with aspirin and clopidogrel were 2.37 (95% CI, 2.16-2.59) and 2.38 (95% CI, 2.00-2.84), respectively. Among patients included in the FAERS database, the concurrent use of aspirin and clopidogrel with PPIs reduced the adjusted ROR of GI hemorrhagic events. PPIs had little influence on the adjusted ROR of embolic/thrombotic events. These results support the use of PPIs as a preventive measure against GI hemorrhagic events for patients receiving clopidogrel and aspirin.

  1. Drug–drug interaction of microdose and regular-dose omeprazole with a CYP2C19 inhibitor and inducer

    OpenAIRE

    Park G; Bae SH; Park W; Han S; Park M; Shin S; Shin YG; Yim DS

    2017-01-01

    Gab-jin Park,1 Soo Hyeon Bae,1 Wan-Su Park,1 Seunghoon Han,1 Min-Ho Park,2 Seok-Ho Shin,2 Young G Shin,2 Dong-Seok Yim1,2 1Department of Clinical Pharmacology and Therapeutics, Seoul St Mary’s Hospital, PIPET (Pharmacometrics Institute for Practical Education and Training), College of Medicine, Catholic University of Korea, Seoul, South Korea; 2College of Pharmacy, Chungnam National University, Daejeon, South Korea Purpose: A microdose drug–drug interaction (DDI) study may be a ...

  2. d-Amino acid mutation of PMI as potent dual peptide inhibitors of p53-MDM2/MDMX interactions.

    Science.gov (United States)

    Li, Xiang; Liu, Chao; Chen, Si; Hu, Honggang; Su, Jiacan; Zou, Yan

    2017-10-15

    According to the previously reported potent dual l-peptide PMI of p53-MDM2/MDMX interactions, a series of d-amino acid mutational PMI analogues, PMI-1-4, with enhanced proteolytic resistence and in vitro tumor cell inhibitory activities were reported, of which Liposome-PMI-1 showed a stronger inhibitory activity against the U87 cell lines than Nutlin-3. This d-amino acid mutation strategy may give a hand for enhancing the potential of peptide drugs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Synergistic interaction between a PDE5 inhibitor (sildenafil) and a new adenosine A2A receptor agonist (LASSBio-1359) improves pulmonary hypertension in rats.

    Science.gov (United States)

    Alencar, Allan K; Carvalho, Fábio I; Silva, Ananssa M; Martinez, Sabrina T; Calasans-Maia, Jorge A; Fraga, Carlos M; Barreiro, Eliezer J; Zapata-Sudo, Gisele; Sudo, Roberto T

    2018-01-01

    Pulmonary hypertension (PH) is characterized by enhanced pulmonary vascular resistance, which causes right ventricle (RV) pressure overload and results in right sided heart failure and death. This work investigated the effectiveness of a combined therapy with PDE5 inhibitor (PDE5i) and a new adenosine A2A receptor (A2AR) agonist in mitigating monocrotaline (MCT) induced PH in rats. An in vitro isobolographic analysis was performed to identify possible synergistic relaxation effect between sildenafil and LASSBio 1359 in rat pulmonary arteries (PAs). In the in vivo experiments, PH was induced in male Wistar rats by a single intraperitoneal injection of 60 mg/kg MCT. Rats were divided into the following groups: control (saline injection only), MCT + vehicle, MCT + sildenafil, MCT + LASSBio 1359 and MCT + combination of sildenafil and LASSBio 1359. Fourteen days after the MCT injection, rats were treated daily with oral administration of the regimen therapies or vehicle for 14 days. Cardiopulmonary system function and structure were evaluated by echocardiography. RV systolic pressure and PA endothelial function were measured. Isobolographic analysis showed a synergistic interaction between sildenafil and LASSBio 1359 in rat PAs. Combined therapy with sildenafil and LASSBio 1359 but not monotreatment with low dosages of either sildenafil or LASSBio 1359 ameliorated all of PH related abnormalities in cardiopulmonary function and structure in MCT challenged rats. The combination of sildenafil and LASSBio 1359 has a synergistic interaction, suggesting that combined use of these pharmacological targets may be an alternative to improve quality of life and outcomes for PH patients.

  4. Bacillus subtilis RapA phosphatase domain interaction with its substrate, phosphorylated Spo0F, and its inhibitor, the PhrA peptide.

    Science.gov (United States)

    Diaz, Alejandra R; Core, Leighton J; Jiang, Min; Morelli, Michela; Chiang, Christina H; Szurmant, Hendrik; Perego, Marta

    2012-03-01

    Rap proteins in Bacillus subtilis regulate the phosphorylation level or the DNA-binding activity of response regulators such as Spo0F, involved in sporulation initiation, or ComA, regulating competence development. Rap proteins can be inhibited by specific peptides generated by the export-import processing pathway of the Phr proteins. Rap proteins have a modular organization comprising an amino-terminal alpha-helical domain connected to a domain formed by six tetratricopeptide repeats (TPR). In this study, the molecular basis for the specificity of the RapA phosphatase for its substrate, phosphorylated Spo0F (Spo0F∼P), and its inhibitor pentapeptide, PhrA, was analyzed in part by generating chimeric proteins with RapC, which targets the DNA-binding domain of ComA, rather than Spo0F∼P, and is inhibited by the PhrC pentapeptide. In vivo analysis of sporulation efficiency or competence-induced gene expression, as well as in vitro biochemical assays, allowed the identification of the amino-terminal 60 amino acids as sufficient to determine Rap specificity for its substrate and the central TPR3 to TPR5 (TPR3-5) repeats as providing binding specificity toward the Phr peptide inhibitor. The results allowed the prediction and testing of key residues in RapA that are essential for PhrA binding and specificity, thus demonstrating how the widespread structural fold of the TPR is highly versatile, using a common interaction mechanism for a variety of functions in eukaryotic and prokaryotic organisms.

  5. Evaluation of a potential transporter-mediated drug interaction between rosuvastatin and pradigastat, a novel DGAT-1 inhibitor.

    Science.gov (United States)

    Kulmatycki, Kenneth; Hanna, Imad; Meyers, Dan; Salunke, Atish; Movva, Aishwarya; Majumdar, Tapan; Natrillo, Adrienne; Vapurcuyan, Arpine; Rebello, Sam; Sunkara, Gangadhar; Chen, Jin

    2015-05-01

    An in vitro drugdrug interaction (DDI) study was performed to assess the potential for pradigastat to inhibit breast cancer resistance protein (BCRP), organic anion-transporting polypeptide (OATP), and organic anion transporter 3 (OAT3) transport activities. To understand the relevance of these in vitro findings, a clinical pharmacokinetic DDI study using rosuvastatin as a BCRP, OATP, and OAT3 probe substrate was conducted. The study used cell lines that stably expressed or over-expressed the respective transporters. The clinical study was an open-label, single sequence study where subjects (n = 36) received pradigastat (100 mg once daily x 3 days thereafter 40 mg once daily) and rosuvastatin (10 mg once daily), alone and in combination. Pradigastat inhibited BCRP-mediated efflux activity in a dose-dependent fashion in a BCRP over-expressing human ovarian cancer cell line with an IC(50) value of 5 μM. Similarly, pradigastat inhibited OATP1B1, OATP1B3 (estradiol 17β glucuronide transport), and OAT3 (estrone 3 sulfate transport) activity in a concentrationdependent manner with estimated IC(50) values of 1.66 ± 0.95 μM, 3.34 ± 0.64 μM, and 0.973 ± 0.11 μM, respectively. In the presence of steady state pradigastat concentrations, AUC(τ, ss) of rosuvastatin was unchanged and its Cmax,ss decreased by 14% (5.30 and 4.61 ng/mL when administered alone and coadministered with pradigastat, respectively). Pradigastat AUC(τ, ss) and C(max, ss) were unchanged when coadministered with rosuvastatin at steady state. Both rosuvastatin and pradigastat were well tolerated. These data indicate no clinically relevant pharmacokinetic interaction between pradigastat and rosuvastatin.

  6. Potentiation of C1-esterase inhibitor by heparin and interactions with C1s protease as assessed by surface plasmon resonance.

    Science.gov (United States)

    Rajabi, Mohsen; Struble, Evi; Zhou, Zhaohua; Karnaukhova, Elena

    2012-01-01

    Human C1-esterase inhibitor (C1-INH) is a multifunctional plasma protein with a wide range of inhibitory and non-inhibitory properties, mainly recognized as a key down-regulator of the complement and contact cascades. The potentiation of C1-INH by heparin and other glycosaminoglycans (GAGs) regulates a broad spectrum of C1-INH activities in vivo both in normal and disease states. SCOPE OF RESEARCH: We have studied the potentiation of human C1-INH by heparin using Surface Plasmon Resonance (SPR), circular dichroism (CD) and a functional assay. To advance a SPR for multiple-unit interaction studies of C1-INH we have developed a novel (consecutive double capture) approach exploring different immobilization and layout. Our SPR experiments conducted in three different design versions showed marked acceleration in C1-INH interactions with complement protease C1s as a result of potentiation of C1-INH by heparin (from 5- to 11-fold increase of the association rate). Far-UV CD studies suggested that heparin binding did not alter C1-INH secondary structure. Functional assay using chromogenic substrate confirmed that heparin does not affect the amidolytic activity of C1s, but does accelerate its consumption due to C1-INH potentiation. This is the first report that directly demonstrates a significant acceleration of the C1-INH interactions with C1s due to heparin by using a consecutive double capture SPR approach. The results of this study may be useful for further C-INH therapeutic development, ultimately for the enhancement of current C1-INH replacement therapies. Published by Elsevier B.V.

  7. Safety aspects of protease inhibitors for chronic hepatitis C: adverse events and drug-to-drug interactions

    Directory of Open Access Journals (Sweden)

    Rosângela Teixeira

    Full Text Available The standard of care therapy of chronic hepatitis C with the combination of pegylated interferon and ribavirin for 24 or 48 weeks was a remarkable accomplishment of the past decade. However, sustained virological responses rates of about 80% (genotypes 2-3 and 50% (geno 3 type 1 were not satisfactory especially for patients infected with genotype 1. Important advances in the biology of HCV have made possible the development of the direct-acting antiviral agents boceprevir and telaprevir with substantial increase in the rates of sustained virological response with shorter duration of therapy for a large number of patients. However, the complexity of triple therapy is higher and several new side effects are expected suggesting greater expertise in the patient management. Anemia and disgeusia are frequent with boceprevir while cutaneous rash, ranging from mild to severe, is expected with telaprevir. Higher risk of drug-drug interactions demand further clinical consideration of the previous well-known adverse events of pegylated interferon and ribavirin. Identification and prompt management of these potential new problems with boceprevir and telaprevir are crucial in clinical practice for optimizing treatment and assuring safety outcomes to HCV-genotype 1 patients.

  8. Safety aspects of protease inhibitors for chronic hepatitis C: adverse events and drug-to-drug interactions

    Directory of Open Access Journals (Sweden)

    Rosângela Teixeira

    2013-04-01

    Full Text Available The standard of care therapy of chronic hepatitis C with the combination of pegylated interferon and ribavirin for 24 or 48 weeks was a remarkable accomplishment of the past decade. However, sustained virological responses rates of about 80% (genotypes 2-3 and 50% (geno 3 type 1 were not satisfactory especially for patients infected with genotype 1. Important advances in the biology of HCV have made possible the development of the direct-acting antiviral agents boceprevir and telaprevir with substantial increase in the rates of sustained virological response with shorter duration of therapy for a large number of patients. However, the complexity of triple therapy is higher and several new side effects are expected suggesting greater expertise in the patient management. Anemia and disgeusia are frequent with boceprevir while cutaneous rash, ranging from mild to severe, is expected with telaprevir. Higher risk of drug-drug interactions demand further clinical consideration of the previous well-known adverse events of pegylated interferon and ribavirin. Identification and prompt management of these potential new problems with boceprevir and telaprevir are crucial in clinical practice for optimizing treatment and assuring safety outcomes to HCV-genotype 1 patients.

  9. Rosmarinic acid, a new snake venom phospholipase A2 inhibitor from Cordia verbenacea (Boraginaceae): antiserum action potentiation and molecular interaction.

    Science.gov (United States)

    Ticli, Fábio K; Hage, Lorane I S; Cambraia, Rafael S; Pereira, Paulo S; Magro, Angelo J; Fontes, Marcos R M; Stábeli, Rodrigo G; Giglio, José R; França, Suzelei C; Soares, Andreimar M; Sampaio, Suely V

    2005-09-01

    Many plants are used in traditional medicine as active agents against various effects induced by snakebite. The methanolic extract from Cordia verbenacea (Cv) significantly inhibited paw edema induced by Bothrops jararacussu snake venom and by its main basic phospholipase A2 homologs, namely bothropstoxins I and II (BthTXs). The active component was isolated by chromatography on Sephadex LH-20 and by RP-HPLC on a C18 column and identified as rosmarinic acid (Cv-RA). Rosmarinic acid is an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid [2-O-cafeoil-3-(3,4-di-hydroxy-phenyl)-R-lactic acid]. This is the first report of RA in the species C. verbenacea ('baleeira', 'whaler') and of its anti-inflammatory and antimyotoxic properties against snake venoms and isolated toxins. RA inhibited the edema and myotoxic activity induced by the basic PLA2s BthTX-I and BthTX-II. It was, however, less efficient to inhibit the PLA2 activity of BthTX-II and, still less, the PLA2 and edema-inducing activities of the acidic isoform BthA-I-PLA2 from the same venom, showing therefore a higher inhibitory activity upon basic PLA2s. RA also inhibited most of the myotoxic and partially the edema-inducing effects of both basic PLA2s, thus reinforcing the idea of dissociation between the catalytic and pharmacological domains. The pure compound potentiated the ability of the commercial equine polyvalent antivenom in neutralizing lethal and myotoxic effects of the crude venom and of isolated PLA2s in experimental models. CD data presented here suggest that, after binding, no significant conformation changes occur either in the Cv-RA or in the target PLA2. A possible model for the interaction of rosmarinic acid with Lys49-PLA2 BthTX-I is proposed.

  10. Multi-spectroscopic and molecular modeling approaches to elucidate the binding interaction between bovine serum albumin and darunavir, a HIV protease inhibitor

    Science.gov (United States)

    Shi, Jie-Hua; Zhou, Kai-Li; Lou, Yan-Yue; Pan, Dong-Qi

    2018-01-01

    Darunavir (DRV), a second-generation HIV protease inhibitor, is widely used across the world as an important component of HIV therapy. The interaction of DRV with bovine serum albumin (BSA), a major carrier protein, has been studied under simulated physiological conditions (pH 7.4) by multi-spectroscopic techniques in combination with molecular modeling. Fluorescence data revealed that the intrinsic fluorescence of BSA was quenched by DRV in terms of a static quenching procedure due to the formation of the DRV-BSA complex. The results indicated the presence of single weak affinity binding site ( 103 M- 1, 310 K) on protein. The thermodynamic parameters, namely enthalpy change (ΔH0), entropy change (ΔS0) and Gibbs free energy change (ΔG0) were calculated, which signified that the binding reaction was spontaneous, the main binding forces were hydrogen bonding and van der Waals forces. Importantly, competitive binding experiments with three site probes, phenylbutazone (in sub-domain IIA, site I), ibuprofen (in sub-domain IIIA, site II) and artemether (in the interface between sub-domain IIA and IIB, site II'), suggested that DRV was preferentially bound to the hydrophobic cavity in site II' of BSA, and this finding was validated by the docking results. Additionally, synchronous fluorescence, three-dimensional fluorescence and Resonance Rayleigh Scattering (RRS) spectroscopy gave qualitative information on the conformational changes of BSA upon adding DRV, while quantitative data were obtained with Fourier transform infrared spectroscopy (FT-IR).

  11. A novel inhibitor of apoptosis protein (IAP)-interacting protein, Vestigial-like (Vgl)-4, counteracts apoptosis-inhibitory function of IAPs by nuclear sequestration

    International Nuclear Information System (INIS)

    Jin, Hyung-Seung; Park, Hyung-Sun; Shin, Jun-Ha; Kim, Dong-Hwan; Jun, Sung-Hun; Lee, Chang-Jun; Lee, Tae H.

    2011-01-01

    Highlights: → We identified a new IAP binding protein Vgl-4. → Vgl-4 is expressed mainly in the nucleus and triggers a relocalization of IAPs from the cytoplasm to the nucleus. → Vgl-4-mediated IAP nuclear localization was blocked by TRAF2 coexpression. → Vgl-4 suppresses the ability of IAPs to prevent cell death, however TRAF2 can revere the effect of Vgl-4. → Vgl-4 functions as an IAP regulator by binding to IAPs and altering their sub-cellular localization. -- Abstract: The inhibitors of apoptosis proteins (IAP), which include cIAP1, cIAP2 and XIAP, suppress apoptosis through the inhibition of caspases, and the activity of IAPs is regulated by a variety of IAP-binding proteins. Herein, we report the identification of a Vestigial-like 4 (Vgl-4), which functions as a transcription cofactor in cardiac myocytes, as a new IAP binding protein. Vgl-4 is expressed predominantly in the nucleus and its overexpression triggers a relocalization of IAPs from the cytoplasm to the nucleus. cIAP1/2-interacting protein TRAF2 (TNF receptor-associated factor 2) prevented the Vgl-4-driven nuclear localization of cIAP2. Accordingly, the forced relocation of IAPs to the nucleus by Vgl-4 significantly reduced their ability to prevent Bax- and TNFα-induced apoptosis, which can be recovered by co-expression with TRAF2. Our results suggest that Vgl-4 may play a role in the apoptotic pathways by regulating translocation of IAPs between different cell compartments.

  12. Multi-spectroscopic and molecular modeling approaches to elucidate the binding interaction between bovine serum albumin and darunavir, a HIV protease inhibitor.

    Science.gov (United States)

    Shi, Jie-Hua; Zhou, Kai-Li; Lou, Yan-Yue; Pan, Dong-Qi

    2018-01-05

    Darunavir (DRV), a second-generation HIV protease inhibitor, is widely used across the world as an important component of HIV therapy. The interaction of DRV with bovine serum albumin (BSA), a major carrier protein, has been studied under simulated physiological conditions (pH7.4) by multi-spectroscopic techniques in combination with molecular modeling. Fluorescence data revealed that the intrinsic fluorescence of BSA was quenched by DRV in terms of a static quenching procedure due to the formation of the DRV-BSA complex. The results indicated the presence of single weak affinity binding site (~10 3 M -1 , 310K) on protein. The thermodynamic parameters, namely enthalpy change (ΔH 0 ), entropy change (ΔS 0 ) and Gibbs free energy change (ΔG 0 ) were calculated, which signified that the binding reaction was spontaneous, the main binding forces were hydrogen bonding and van der Waals forces. Importantly, competitive binding experiments with three site probes, phenylbutazone (in sub-domain IIA, site I), ibuprofen (in sub-domain IIIA, site II) and artemether (in the interface between sub-domain IIA and IIB, site II'), suggested that DRV was preferentially bound to the hydrophobic cavity in site II' of BSA, and this finding was validated by the docking results. Additionally, synchronous fluorescence, three-dimensional fluorescence and Resonance Rayleigh Scattering (RRS) spectroscopy gave qualitative information on the conformational changes of BSA upon adding DRV, while quantitative data were obtained with Fourier transform infrared spectroscopy (FT-IR). Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Small tyrosine kinase inhibitors interrupt EGFR signaling by interacting with erbB3 and erbB4 in glioblastoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco-Garcia, Estefania; Saceda, Miguel [Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, 03202 Elche (Alicante) (Spain); Unidad de Investigacion, Hospital General Universitario de Elche, 03203 Elche (Alicante) (Spain); Grasso, Silvina; Rocamora-Reverte, Lourdes; Conde, Mariano; Gomez-Martinez, Angeles [Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, 03202 Elche (Alicante) (Spain); Garcia-Morales, Pilar [Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, 03202 Elche (Alicante) (Spain); Unidad de Investigacion, Hospital General Universitario de Elche, 03203 Elche (Alicante) (Spain); Ferragut, Jose A. [Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, 03202 Elche (Alicante) (Spain); Martinez-Lacaci, Isabel, E-mail: imlacaci@umh.es [Instituto de Biologia Molecular y Celular, Universidad Miguel Hernandez, 03202 Elche (Alicante) (Spain); Unidad AECC de Investigacion Traslacional en Cancer, Hospital Universitario Virgen de la Arrixaca, 30120 Murcia (Spain)

    2011-06-10

    Signaling through the epidermal growth factor receptor (EGFR) is relevant in glioblastoma. We have determined the effects of the EGFR inhibitor AG1478 in glioblastoma cell lines and found that U87 and LN-229 cells were very sensitive to this drug, since their proliferation diminished and underwent a marked G{sub 1} arrest. T98 cells were a little more refractory to growth inhibition and A172 cells did not undergo a G{sub 1} arrest. This G{sub 1} arrest was associated with up-regulation of p27{sup kip1}, whose protein turnover was stabilized. EGFR autophosphorylation was blocked with AG1478 to the same extent in all the cell lines. Other small-molecule EGFR tyrosine kinase inhibitors employed in the clinic, such as gefitinib, erlotinib and lapatinib, were able to abrogate proliferation of glioblastoma cell lines, which underwent a G{sub 1} arrest. However, the EGFR monoclonal antibody, cetuximab had no effect on cell proliferation and consistently, had no effect on cell cycle either. Similarly, cetuximab did not inhibit proliferation of U87 {Delta}EGFR cells or primary glioblastoma cell cultures, whereas small-molecule EGFR inhibitors did. Activity of downstream signaling molecules of EGFR such as Akt and especially ERK1/2 was interrupted with EGFR tyrosine kinase inhibitors, whereas cetuximab treatment could not sustain this blockade over time. Small-molecule EGFR inhibitors were able to prevent phosphorylation of erbB3 and erbB4, whereas cetuximab only hindered EGFR phosphorylation, suggesting that EGFR tyrosine kinase inhibitors may mediate their anti-proliferative effects through other erbB family members. We can conclude that small-molecule EGFR inhibitors may be a therapeutic approach for the treatment of glioblastoma patients.

  14. Clopidogrel-Proton Pump Inhibitor Drug-Drug Interaction and Risk of Adverse Clinical Outcomes Among PCI-Treated ACS Patients: A Meta-analysis.

    Science.gov (United States)

    Serbin, Michael A; Guzauskas, Gregory F; Veenstra, David L

    2016-08-01

    Uncertainty regarding clopidogrel effectiveness attenuation because of a drug-drug interaction with proton pump inhibitors (PPI) has led to conflicting guidelines on concomitant therapy. In particular, the effect of this interaction in patients who undergo a percutaneous coronary intervention (PCI), a population known to have increased risk of adverse cardiovascular events, has not been systematically evaluated. To synthesize the evidence of the effect of clopidogrel-PPI drug interaction on adverse cardiovascular outcomes in a PCI patient population. We conducted a systematic literature review for studies reporting clinical outcomes in patients who underwent a PCI and were initiated on clopidogrel with or without a PPI. Studies were included in the analysis if they reported at least 1 of the clinical outcomes of interest (major adverse cardiovascular event [MACE], cardiovascular death, all-cause death, myocardial infarction, stroke, stent thrombosis, and bleed events). We excluded studies that were not exclusive to PCI patients or had no PCI subgroup analysis and/or did not report at least a 6-month follow-up. Statistical and clinical heterogeneity were evaluated and HRs and 95% CIs for adverse clinical events were pooled using the DerSimonian and Laird random-effects meta-analysis method. We identified 12 studies comprising 50,277 PCI patients that met our inclusion and exclusion criteria. Our analysis included retrospective analyses of randomized controlled trials (2), health registries (3), claims databases (2), and institutional records (5); no prospective studies of PCI patients were identified. On average, patients were in their mid-60s, male, and had an array of comorbidities, including hyperlipidemia, diabetes, hypertension, and smoking history. Concomitant therapy following PCI resulted in statistically significant increases in composite MACE (HR = 1.28; 95% CI = 1.24-1.32), myocardial infarction (HR = 1.51; 95% CI = 1.40-1.62), and stroke (HR = 1.46; 95

  15. Role of 5′TG3′-interacting factors (TGIFs) in Vorinostat (HDAC inhibitor)-mediated Corneal Fibrosis Inhibition

    Science.gov (United States)

    Sharma, Ajay; Sinha, Nishant R.; Siddiqui, Saad

    2015-01-01

    Purpose We have previously reported that vorinostat, an FDA-approved, clinically used histone deacetylase (HDAC) inhibitor, attenuates corneal fibrosis in vivo in rabbits by blocking transforming growth factor β (TGFβ). The 5′TG3′-interacting factors (TGIFs) are transcriptional repressors of TGFβ1 signaling via the Smad pathway. The present study was designed to explore the expression of TGIFs in human corneal fibroblasts and to investigate their role in mediating the antifibrotic effect of vorinostat. Methods Human corneal fibroblast cultures were generated from donor corneas. RNA isolation, cDNA preparation, and PCR were performed to detect the presence of TGIF1 and TGIF2 transcripts. The cultures were exposed to vorinostat (2.5 µM) to test its effect on TGIF mRNA and protein levels using qPCR and immunoblotting. Myofibroblast formation was induced with TGFβ1 (5 ng/ml) treatment under serum-free conditions. The changes in fibrosis parameters were quantified by measuring fibrosis marker α-smooth muscle actin (αSMA) mRNA and protein levels with qPCR, immunostaining, and immunoblotting. Smad2/3/4 and TGIF knockdowns were performed using pre-validated RNAi/siRNAs and a commercially available transfection reagent. Results Human corneal fibroblasts showed the expression of TGIF1 and TGIF2. Vorinostat (2.5 µM) caused a 2.8–3.3-fold increase in TGIF1 and TGIF2 mRNA levels and a 1.4–1.8-fold increase in TGIF1 and TGIF2 protein levels. Vorinostat treatment also caused a significant increase in acetylhistone H3 and acetylhistone H4. Vorinostat-induced increases in TGIF1 and TGIF2 were accompanied by a concurrent decrease in corneal fibrosis, as indicated by a decrease in αSMA mRNA by 83±7.7% and protein levels by 97±5%. The RNAi-mediated knockdown of Smad2, Smad3, and Smad4 markedly attenuated TGFβ1-evoked transdifferentiation of fibroblasts to myofibroblasts. The siRNA-mediated knockdown of TGIF1 and TGIF2 neutralized vorinostat-evoked decreases in

  16. Mutational analysis of the β-trefoil fold protein barley α-amylase/subtilisin inhibitor probes hot spots for the interaction with barley α-amylase

    DEFF Research Database (Denmark)

    Bønsager, Birgit Christine; Nielsen, P. 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...

  17. [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.

  18. Syk inhibitors.

    Science.gov (United States)

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

    2013-01-01

    Non-receptor type of protein-tyrosine kinase Syk (spleen tyrosine kinase) was isolated in University of Fukui in 1991. Syk is most highly expressed by haemopoietic cells and known to play crucial roles in the signal transduction through various immunoreceptors of the adaptive immune response. However, recent reports demonstrate that Syk also mediates other biological functions, such as innate immune response, osteoclast maturation, platelet activation and cellular adhesion. Moreover, ectopic expression of Syk by epigenetic changes is reported to cause retinoblastoma. Because of its critical roles on the cellular functions, the development of Syk inhibitors for clinical use has been desired. Although many candidate compounds were produced, none of them had progressed to clinical trials. However, novel Syk inhibitors were finally 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 the novel Syk inhibitors and their current status. In addition, we will introduce our research focused on the functions of Syk on Dectin-1-mediated mast cell activation.

  19. Modeling Chemical Interaction Profiles: I. Spectral Data-Activity Relationship and Structure-Activity Relationship Models for Inhibitors and Non-inhibitors of Cytochrome P450 CYP3A4 and CYP2D6 Isozymes

    OpenAIRE

    McPhail, Brooks; Tie, Yunfeng; Hong, Huixiao; Pearce, Bruce A.; Schnackenberg, Laura K.; Ge, Weigong; Valerio, Luis G.; Fuscoe, James C.; Tong, Weida; Buzatu, Dan A.; Wilkes, Jon G.; Fowler, Bruce A.; Demchuk, Eugene; Beger, Richard D.

    2012-01-01

    An interagency collaboration was established to model chemical interactions that may cause adverse health effects when an exposure to a mixture of chemicals occurs. Many of these chemicals—drugs, pesticides, and environmental pollutants—interact at the level of metabolic biotransformations mediated by cytochrome P450 (CYP) enzymes. In the present work, spectral data-activity relationship (SDAR) and structure-activity relationship (SAR) approaches were used to develop machine-learning classifi...

  20. Interaction between amiodarone and hepatitis-C virus nucleotide inhibitors in human induced pluripotent stem cell-derived cardiomyocytes and HEK-293 Cav1.2 over-expressing cells.

    Science.gov (United States)

    Lagrutta, Armando; Zeng, Haoyu; Imredy, John; Balasubramanian, Bharathi; Dech, Spencer; Lis, Edward; Wang, Jixin; Zhai, Jin; DeGeorge, Joseph; Sannajust, Frederick

    2016-10-01

    Several clinical cases of severe bradyarrhythmias have been reported upon co-administration of the Hepatitis-C NS5B Nucleotide Polymerase Inhibitor (HCV-NI) direct-acting antiviral agent, sofosbuvir (SOF), and the Class-III anti-arrhythmic amiodarone (AMIO). We model the cardiac drug-drug interaction (DDI) between AMIO and SOF, and between AMIO and a closely-related SOF analog, MNI-1 (Merck Nucleotide Inhibitor #1), in functional assays of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), to provide mechanistic insights into recently reported clinical cases. AMIO co-applied with SOF or MNI-1 increased beating rate or field potential (FP) rate and decreased impedance (IMP) and Ca(2+) transient amplitudes in hiPSC-CM syncytia. This action resembled that of Ca(2+) channel blockers (CCBs) in the model, but CCBs did not substitute for AMIO in the DDI. AMIO analog dronedarone (DRON) did not substitute for, but competed with AMIO in the DDI. Ryanodine and thapsigargin, decreasing intracellular Ca(2+) stores, and SEA-0400, a Na(+)/Ca(2+) exchanger-1 (NCX1) inhibitor, partially antagonized or suppressed DDI effects. Other agents affecting FP rate only exerted additive or subtractive effects, commensurate with their individual effects. We also describe an interaction between AMIO and MNI-1 on Cav1.2 ion channels in an over-expressing HEK-293 cell line. MNI-1 enhanced Cav1.2 channel inhibition by AMIO, but did not affect inhibition of Cav1.2 by DRON, verapamil, nifedipine, or diltiazem. Our data in hiPSC-CMs indicate that HCV-NI agents such as SOF and MNI-1 interact with key intracellular Ca(2+)-handling mechanisms. Additional study in a Cav1.2 HEK-293 cell-line suggests that HCV-NIs potentiate the inhibitory action of AMIO on L-type Ca(2+) channels. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Identification and characterization of small molecule inhibitors of the calcium-dependent S100B-p53 tumor suppressor interaction.

    Science.gov (United States)

    Markowitz, Joseph; Chen, Ijen; Gitti, Rossi; Baldisseri, Donna M; Pan, Yongping; Udan, Ryan; Carrier, France; MacKerell, Alexander D; Weber, David J

    2004-10-07

    The binding of S100B to p53 down-regulates wild-type p53 tumor suppressor activity in cancer cells such as malignant melanoma, so a search for small molecules that bind S100B and prevent S100B-p53 complex formation was undertaken. Chemical databases were computationally searched for potential inhibitors of S100B, and 60 compounds were selected for testing on the basis of energy scoring, commercial availability, and chemical similarity clustering. Seven of these compounds bound to S100B as determined by steady state fluorescence spectroscopy (1.0 microM model of one such inhibitor, pentamidine, bound to Ca(2+)-loaded S100B was calculated using intermolecular NOE data between S100B and the drug, and indicates that pentamidine binds into the p53 binding site on S100B defined by helices 3 and 4 and loop 2 (termed the hinge region).

  2. INTERACT

    DEFF Research Database (Denmark)

    Jochum, Elizabeth; Borggreen, Gunhild; Murphey, TD

    This paper considers the impact of visual art and performance on robotics and human-computer interaction and outlines a research project that combines puppetry and live performance with robotics. Kinesics—communication through movement—is the foundation of many theatre and performance traditions ...

  3. Interaction between amiodarone and hepatitis-C virus nucleotide inhibitors in human induced pluripotent stem cell-derived cardiomyocytes and HEK-293 Cav{sub 1.2} over-expressing cells

    Energy Technology Data Exchange (ETDEWEB)

    Lagrutta, Armando, E-mail: armando_lagrutta@merck.com; Zeng, Haoyu; Imredy, John; Balasubramanian, Bharathi; Dech, Spencer; Lis, Edward; Wang, Jixin; Zhai, Jin; DeGeorge, Joseph; Sannajust, Frederick

    2016-10-01

    Several clinical cases of severe bradyarrhythmias have been reported upon co-administration of the Hepatitis-C NS5B Nucleotide Polymerase Inhibitor (HCV-NI) direct-acting antiviral agent, sofosbuvir (SOF), and the Class-III anti-arrhythmic amiodarone (AMIO). We model the cardiac drug-drug interaction (DDI) between AMIO and SOF, and between AMIO and a closely-related SOF analog, MNI-1 (Merck Nucleotide Inhibitor #1), in functional assays of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), to provide mechanistic insights into recently reported clinical cases. AMIO co-applied with SOF or MNI-1 increased beating rate or field potential (FP) rate and decreased impedance (IMP) and Ca{sup 2+} transient amplitudes in hiPSC-CM syncytia. This action resembled that of Ca{sup 2+} channel blockers (CCBs) in the model, but CCBs did not substitute for AMIO in the DDI. AMIO analog dronedarone (DRON) did not substitute for, but competed with AMIO in the DDI. Ryanodine and thapsigargin, decreasing intracellular Ca{sup 2+} stores, and SEA-0400, a Na{sup +}/Ca{sup 2+} exchanger-1 (NCX1) inhibitor, partially antagonized or suppressed DDI effects. Other agents affecting FP rate only exerted additive or subtractive effects, commensurate with their individual effects. We also describe an interaction between AMIO and MNI-1 on Cav{sub 1.2} ion channels in an over-expressing HEK-293 cell line. MNI-1 enhanced Cav{sub 1.2} channel inhibition by AMIO, but did not affect inhibition of Cav{sub 1.2} by DRON, verapamil, nifedipine, or diltiazem. Our data in hiPSC-CMs indicate that HCV-NI agents such as SOF and MNI-1 interact with key intracellular Ca{sup 2+}-handling mechanisms. Additional study in a Cav{sub 1.2} HEK-293 cell-line suggests that HCV-NIs potentiate the inhibitory action of AMIO on L-type Ca{sup 2+} channels. - Highlights: • Adverse clinical interaction between amiodarone and HCV-NI drugs is captured by in vitro models. • Human iPSC-derived cardiomyocyte

  4. Rapid, Automated, and Specific Immunoassay to Directly Measure Matrix Metalloproteinase-9–Tissue Inhibitor of Metalloproteinase-1 Interactions in Human Plasma Using AlphaLISA Technology: A New Alternative to Classical ELISA

    Directory of Open Access Journals (Sweden)

    Helena Pulido-Olmo

    2017-07-01

    Full Text Available The protocol describes a novel, rapid, and no-wash one-step immunoassay for highly sensitive and direct detection of the complexes between matrix metalloproteinases (MMPs and their tissue inhibitor of metalloproteinases (TIMPs based on AlphaLISA® technology. We describe two procedures: (i one approach is used to analyze MMP-9–TIMP-1 interactions using recombinant human MMP-9 with its corresponding recombinant human TIMP-1 inhibitor and (ii the second approach is used to analyze native or endogenous MMP-9–TIMP-1 protein interactions in samples of human plasma. Evaluating native MMP-9–TIMP-1 complexes using this approach avoids the use of indirect calculations of the MMP-9/TIMP-1 ratio for which independent MMP-9 and TIMP-1 quantifications by two conventional ELISAs are needed. The MMP-9–TIMP-1 AlphaLISA® assay is quick, highly simplified, and cost-effective and can be completed in less than 3 h. Moreover, the assay has great potential for use in basic and preclinical research as it allows direct determination of native MMP-9–TIMP-1 complexes in circulating blood as biofluid.

  5. A high-affinity, dimeric inhibitor of PSD-95 bivalently interacts with PDZ1-2 and protects against ischemic brain damage

    DEFF Research Database (Denmark)

    Bach, Anders*; Clausen, Bettina H; Møller, Magda

    2012-01-01

    Inhibition of the ternary protein complex of the synaptic scaffolding protein postsynaptic density protein-95 (PSD-95), neuronal nitric oxide synthase (nNOS), and the N-methyl-d-aspartate (NMDA) receptor is a potential strategy for treating ischemic brain damage, but high-affinity inhibitors are ...... of Tat-N-dimer (3 nmol/g) to mice subjected to focal cerebral ischemia reduces infarct volume with 40% and restores motor functions. Thus, Tat-N-dimer is a highly efficacious neuroprotective agent with therapeutic potential in stroke....

  6. Structure-based virtual screening toward the discovery of novel inhibitors for impeding the protein-protein interaction between HIV-1 integrase and human lens epithelium-derived growth factor (LEDGF/p75).

    Science.gov (United States)

    Panwar, Umesh; Singh, Sanjeev Kumar

    2017-10-23

    HIV-1 integrase is a unique promising component of the viral replication cycle, catalyzing the integration of reverse transcribed viral cDNA into the host cell genome. Generally, IN activity requires both viral as well as a cellular co-factor in the processing replication cycle. Among them, the human lens epithelium-derived growth factor (LEDGF/p75) represented as promising cellular co-factor which supports the viral replication by tethering IN to the chromatin. Due to its major importance in the early steps of HIV replication, the interaction between IN and LEDGF/p75 has become a pleasing target for anti-HIV drug discovery. The present study involves the finding of novel inhibitor based on the information of dimeric CCD of IN in complex with known inhibitor, which were carried out by applying a structure-based virtual screening concept with molecular docking. Additionally, Free binding energy, ADME properties, PAINS analysis, Density Functional Theory, and Enrichment Calculations were performed on selected compounds for getting a best lead molecule. On the basis of these analyses, the current study proposes top 3 compounds: Enamine-Z742267384, Maybridge-HTS02400, and Specs-AE-848/37125099 with acceptable pharmacological properties and enhanced binding affinity to inhibit the interaction between IN and LEDGF/p75. Furthermore, Simulation studies were carried out on these molecules to expose their dynamics behavior and stability. We expect that the findings obtained here could be future therapeutic agents and may provide an outline for the experimental studies to stimulate the innovative strategy for research community.

  7. Synergistic interactions between a variety of insecticides and an ergosterol biosynthesis inhibitor fungicide in dietary exposures of bumble bees (Bombus terrestris L.).

    Science.gov (United States)

    Raimets, Risto; Karise, Reet; Mänd, Marika; Kaart, Tanel; Ponting, Sally; Song, Jimao; Cresswell, James E

    2018-03-01

    In recent years, concern has been raised over honey bee colony losses, and also among wild bees there is evidence for extinctions and range contractions in Europe and North America. Pesticides have been proposed as a potential cause of this decline. Bees are exposed simultaneously to a variety of agrochemicals, which may cause synergistically detrimental impacts, which are incompletely understood. We investigated the toxicity of the fungicide imazalil in mixture with four common insecticides: fipronil (phenylpyrazoid), cypermethrin (pyrethroid), thiamethoxam, and imidacloprid (neonicotinoids). Ergosterol biosynthesis inhibitor (EBI) fungicides like imazalil can inhibit P450 detoxification systems in insects and therefore fungicide - insecticide co-occurrence might produce synergistic toxicity in bees. We assessed the impact of dietary fungicide - insecticide mixtures on the mortality and feeding rates of laboratory bumble bees (Bombus terrestris L.). Regarding mortality, imazalil synergised the toxicity of fipronil, cypermethrin and thiamethoxam, but not imidacloprid. We found no synergistic effects on feeding rates. Our findings suggest that P450-based detoxification processes are differentially important in mitigating the toxicity of certain insecticides, even those of the same chemical class. Our evidence that cocktail effects can arise in bumble bees should extend concern about the potential impacts of agrochemical mixtures to include wild bee species in farmland. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  8. Assessment of Interactions between Cisplatin and Two Histone Deacetylase Inhibitors in MCF7, T47D and MDA-MB-231 Human Breast Cancer Cell Lines - An Isobolographic Analysis.

    Directory of Open Access Journals (Sweden)

    Anna Wawruszak

    Full Text Available Histone deacetylase inhibitors (HDIs are promising anticancer drugs, which inhibit proliferation of a wide variety of cancer cells including breast carcinoma cells. In the present study, we investigated the influence of valproic acid (VPA and suberoylanilide hydroxamic acid (SAHA, vorinostat, alone or in combination with cisplatin (CDDP on proliferation, induction of apoptosis and cell cycle progression in MCF7, T47D and MDA-MB-231 human breast carcinoma cell lines. The type of interaction between HDIs and CDDP was determined by an isobolographic analysis. The isobolographic analysis is a very precise and rigorous pharmacodynamic method, to determine the presence of synergism, addition or antagonism between different drugs with using variety of fixed dose ratios. Our experiments show that the combinations of CDDP with SAHA or VPA at a fixed-ratio of 1:1 exerted additive interaction in the viability of MCF7 cells, while in T47D cells there was a tendency to synergy. In contrast, sub-additive (antagonistic interaction was observed for the combination of CDDP with VPA in MDA-MB-231 "triple-negative" (i.e. estrogen receptor negative, progesterone receptor negative, and HER-2 negative human breast cancer cells, whereas combination of CDDP with SAHA in the same MDA-MB-231 cell line yielded additive interaction. Additionally, combined HDIs/CDDP treatment resulted in increase in apoptosis and cell cycle arrest in all tested breast cancer cell lines in comparison with a single therapy. In conclusion, the additive interaction of CDDP with SAHA or VPA suggests that HDIs could be combined with CDDP in order to optimize treatment regimen in some human breast cancers.

  9. The Mechanism of Action of the Histone Deacetylase Inhibitor Vorinostat Involves Interaction with the Insulin-Like Growth Factor Signaling Pathway

    Science.gov (United States)

    Sarfstein, Rive; Bruchim, Ilan; Fishman, Ami; Werner, Haim

    2011-01-01

    A correlation between components of the insulin-like growth factor (IGF) system and endometrial cancer risk has been shown in recent studies. The antitumor action of vorinostat, a histone deacetylase inhibitor, involves changes in the expression of specific genes via acetylation of histones and transcription factors. The aim of this study was to establish whether vorinostat can modify the expression of specific genes related to the IGF-I receptor (IGF-IR) signaling pathway and revert the transformed phenotype. Human endometrioid (Type I, Ishikawa) and uterine serous papillary (Type II, USPC-2) endometrial cancer cell lines were treated with vorinostat in the presence or absence of IGF-I. Vorinostat increased IGF-IR phosphorylation, produced acetylation of histone H3, up-regulated pTEN and p21 expression, and reduced p53 and cyclin D1 levels in Ishikawa cells. Vorinostat up-regulated IGF-IR and p21 expression, produced acetylation of histone H3, and down-regulated the expression of total AKT, pTEN and cyclin D1 in USPC-2 cells. Of interest, IGF-IR activation was associated with a major elevation in IGF-IR promoter activity. In addition, vorinostat treatment induced apoptosis in both cell lines and abolished the anti-apoptotic activity of IGF-I both in the absence or presence of a humanized monoclonal IGF-IR antibody, MK-0646. Finally, vorinostat treatment led to a significant decrease in proliferation and colony forming capability in both cell lines. In summary, our studies demonstrate that vorinostat exhibits a potent apoptotic and anti-proliferative effect in both Type I and II endometrial cancer cells, thus suggesting that endometrial cancer may be therapeutically targeted by vorinostat. PMID:21931726

  10. The mechanism of action of the histone deacetylase inhibitor vorinostat involves interaction with the insulin-like growth factor signaling pathway.

    Directory of Open Access Journals (Sweden)

    Rive Sarfstein

    Full Text Available A correlation between components of the insulin-like growth factor (IGF system and endometrial cancer risk has been shown in recent studies. The antitumor action of vorinostat, a histone deacetylase inhibitor, involves changes in the expression of specific genes via acetylation of histones and transcription factors. The aim of this study was to establish whether vorinostat can modify the expression of specific genes related to the IGF-I receptor (IGF-IR signaling pathway and revert the transformed phenotype. Human endometrioid (Type I, Ishikawa and uterine serous papillary (Type II, USPC-2 endometrial cancer cell lines were treated with vorinostat in the presence or absence of IGF-I. Vorinostat increased IGF-IR phosphorylation, produced acetylation of histone H3, up-regulated pTEN and p21 expression, and reduced p53 and cyclin D1 levels in Ishikawa cells. Vorinostat up-regulated IGF-IR and p21 expression, produced acetylation of histone H3, and down-regulated the expression of total AKT, pTEN and cyclin D1 in USPC-2 cells. Of interest, IGF-IR activation was associated with a major elevation in IGF-IR promoter activity. In addition, vorinostat treatment induced apoptosis in both cell lines and abolished the anti-apoptotic activity of IGF-I both in the absence or presence of a humanized monoclonal IGF-IR antibody, MK-0646. Finally, vorinostat treatment led to a significant decrease in proliferation and colony forming capability in both cell lines. In summary, our studies demonstrate that vorinostat exhibits a potent apoptotic and anti-proliferative effect in both Type I and II endometrial cancer cells, thus suggesting that endometrial cancer may be therapeutically targeted by vorinostat.

  11. D77, one benzoic acid derivative, functions as a novel anti-HIV-1 inhibitor targeting the interaction between integrase and cellular LEDGF/p75

    International Nuclear Information System (INIS)

    Du Li; Zhao Yaxue; Chen, Jing; Yang Liumeng; Zheng Yongtang; Tang Yun; Shen Xu; Jiang Hualiang

    2008-01-01

    Integration of viral-DNA into host chromosome mediated by the viral protein HIV-1 integrase (IN) is an essential step in the HIV-1 life cycle. In this process, Lens epithelium-derived growth factor (LEDGF/p75) is discovered to function as a cellular co-factor for integration. Since LEDGF/p75 plays an important role in HIV integration, disruption of the LEDGF/p75 interaction with IN has provided a special interest for anti-HIV agent discovery. In this work, we reported that a benzoic acid derivative, 4-[(5-bromo-4-{[2,4-dioxo-3-(2-oxo-2-phenylethyl) -1,3-thiazolidin-5-ylidene]methyl}-2-ethoxyphenoxy)methyl]benzoic acid (D77) could potently inhibit the IN-LEDGF/p75 interaction and affect the HIV-1 IN nuclear distribution thus exhibiting antiretroviral activity. Molecular docking with site-directed mutagenesis analysis and surface plasmon resonance (SPR) binding assays has clarified possible binding mode of D77 against HIV-1 integrase. As the firstly discovered small molecular compound targeting HIV-1 integrase interaction with LEDGF/p75, D77 might supply useful structural information for further anti-HIV agent discovery

  12. B7-H3 is a potent inhibitor of human T cell activation: No evidence for B7-H3 and TREML2 interaction

    Science.gov (United States)

    Leitner, Judith; Klauser, Christoph; Pickl, Winfried F.; Stöckl, Johannes; Majdic, Otto; Bardet, Anaïs F.; Kreil, David P.; Dong, Chen; Yamazaki, Tomohide; Zlabinger, Gerhard; Pfistershammer, Katharina; Steinberger, Peter

    2010-01-01

    B7-H3 belongs to the B7 superfamily, a group of molecules that costimulate or down-modulate T cell responses. Although it was shown that B7-H3 can inhibit T cell responses, several studies - most of them performed in murine systems - found B7-H3 to act in a costimulatory manner. In this study we have specifically addressed a potential functional dualism of human B7-H3 by assessing the effect of this molecule under varying experimental conditions as well as on different T cell subsets. We show that B7-H3 does not costimulate human T cells. In presence of strong activating signals, B7-H3 potently and consistently down-modulated human T cell responses. This inhibitory effect was evident when analyzing proliferation and cytokine production and affected naïve as well as pre-activated T cells. We furthermore demonstrate that B7-H3 - T cell interaction is characterized by an early suppression of IL-2 and that T cell inhibition can be reverted by exogenous IL-2. Since TREML2 has been recently described as costimulatory receptor of murine B7-H3 we have extensively analysed interaction of human B7-H3 with TREML2 (TLT2). In these experiments we found no evidence for such an interaction. Furthermore our data do not point to a role for murine TREML2 as a receptor for murine B7-H3. PMID:19544488

  13. DFT Study of Azole Corrosion Inhibitors on Cu2O Model of Oxidized Copper Surfaces: II. Lateral Interactions and Thermodynamic Stability

    Directory of Open Access Journals (Sweden)

    Dunja Gustinčič

    2018-05-01

    Full Text Available The adsorption of imidazole, triazole, and tetrazole—used as simple models of azole corrosion inhibitors—on various Cu 2 O(111- and Cu 2 O(110-type surfaces was characterized using density functional theory (DFT calculations with the focus on lateral intermolecular interactions and the thermodynamic stability of various adsorption structures. To this end, an ab initio thermodynamics approach was used to construct two-dimensional phase diagrams for all three molecules. The impact of van der Waals dispersion interactions on molecular adsorption bonding was also addressed. Lateral intermolecular interactions were found to be the most repulsive for imidazole and the least for tetrazole, for which they are usually even slightly attractive. Both non-dissociative and dissociative adsorption modes were considered and although dissociated molecules bind to surfaces more strongly, none of the considered structures that involve dissociated molecules appear on the phase diagrams. Our results show that the three azole molecules display a strong tendency to preferentially adsorb at reactive coordinatively unsaturated (CUS Cu surface sites and stabilize them. According to the calculated phase diagrams for Cu 2 O(111-type surfaces, the three azole molecules adsorb to specific CUS sites, designated as Cu CUS , under all conditions at which molecular adsorption is stable. This tentatively suggests that their corrosion inhibition capability may stem, at least in part, from their ability to passivate reactive surface sites. We further comment on a specific drawback due to neglect of configurational entropy that is usually utilized within the ab initio thermodynamics approach. We analyze the issue for Langmuir and Frumkin adsorption models and show that when configurational entropy is neglected, the ab initio thermodynamics approach is too hasty to predict phase-transition like behavior.

  14. Isolation, identification and molecular docking as cyclooxygenase (COX) inhibitors of the main constituents of Matricaria chamomilla L. extract and its synergistic interaction with diclofenac on nociception and gastric damage in rats.

    Science.gov (United States)

    Ortiz, Mario I; Fernández-Martínez, Eduardo; Soria-Jasso, Luis Enrique; Lucas-Gómez, Isaac; Villagómez-Ibarra, Roberto; González-García, Martha P; Castañeda-Hernández, Gilberto; Salinas-Caballero, Mireya

    2016-03-01

    Chamomile (Matricaria chamomilla L., Asteraceae) is a medicinal plant widely used as remedy for pain and gastric disorders. The association of non-steroidal anti-inflammatory drugs (NSAIDs) with medicinal plant extracts may increase its antinociceptive activity, permit the use of lower doses and limit side effects. The aim was to isolate and identify the main chemical constituents of Matricaria chamomilla ethanolic extract (MCE) as well as to explore their activity as cyclooxygenase (COX) inhibitors in silico; besides, to examine the interaction between MCE and diclofenac on nociception in the formalin test by isobolographic analysis, and to determine the level of gastric injury in rats. Three terpenoids, α-bisabolol, bisabolol oxide A, and guaiazulene, were isolated and identified by (1)H NMR. Docking simulation predicted COX inhibitory activity for those terpenoids. Diclofenac, MCE, or their combinations produced an antinociceptive effect. The sole administration of diclofenac and the highest combined dose diclofenac-MCE produced significant a gastric damage, but that effect was not seen with MCE alone. An isobologram was constructed and the derived theoretical ED35 for the antinociceptive effect was significantly different from the experimental ED35; hence, the interaction between diclofenac and MCE that mediates the antinociceptive effect is synergist. The MCE contains three major terpenoids with plausible COX inhibitory activity in silico, but α-bisabolol showed the highest affinity. Data suggest that the diclofenac-MCE combination can interact at the systemic level in a synergic manner and may have therapeutic advantages for the clinical treatment of inflammatory pain. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  15. Chemical Synthesis and Evaluation of a Disialic Acid-Containing Dextran Polymer as an Inhibitor for the Interaction between Siglec 7 and Its Ligand.

    Science.gov (United States)

    Yamaguchi, Sho; Yoshimura, Atsushi; Yasuda, Yu; Mori, Airi; Tanaka, Hiroshi; Takahashi, Takashi; Kitajima, Ken; Sato, Chihiro

    2017-07-04

    A new sialic acid (Sia)-containing glycopolymer-a fluorescent probe with high-density disialic acid (diSia) on the surface of polysaccharide dextran (diSia-Dex)-was synthesized as a key molecule to regulate the Sia recognition lectins, Siglecs, that are involved in the immune system. According to our original methods, diSia was synthesized by α-selective sialylation, and a dextran template possessing terminal acetylenes and amino groups was prepared. A diSia and a fluorescent molecule were subsequently introduced to surface-modified dextran by Hüisgen reaction and amidation, respectively. The modulatory activity of Siglec7 was evaluated by using synthetic probes. DiSia-Dex showed high binding avidity toward Siglec7, with a K D value of 5.87×10 -10  m, and a high inhibitory activity for the interaction between Siglec7 and a ligand (GD3), with a IC 50 value of 1.0 nm. Notably, diSia-Dex was able to release Siglec7 from the pre-existing Siglec7-GD3 complex, possibly due to its unique properties of a slow dissociation rate and a high association rate. Together, these data show that diSia-Dex can be widely applicable as a modulator of Siglec7 functions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Prediction of Drug-Drug Interactions with Bupropion and Its Metabolites as CYP2D6 Inhibitors Using a Physiologically-Based Pharmacokinetic Model.

    Science.gov (United States)

    Xue, Caifu; Zhang, Xunjie; Cai, Weimin

    2017-12-21

    The potential of inhibitory metabolites of perpetrator drugs to contribute to drug-drug interactions (DDIs) is uncommon and underestimated. However, the occurrence of unexpected DDI suggests the potential contribution of metabolites to the observed DDI. The aim of this study was to develop a physiologically-based pharmacokinetic (PBPK) model for bupropion and its three primary metabolites-hydroxybupropion, threohydrobupropion and erythrohydrobupropion-based on a mixed "bottom-up" and "top-down" approach and to contribute to the understanding of the involvement and impact of inhibitory metabolites for DDIs observed in the clinic. PK profiles from clinical researches of different dosages were used to verify the bupropion model. Reasonable PK profiles of bupropion and its metabolites were captured in the PBPK model. Confidence in the DDI prediction involving bupropion and co-administered CYP2D6 substrates could be maximized. The predicted maximum concentration (C max ) area under the concentration-time curve (AUC) values and C max and AUC ratios were consistent with clinically observed data. The addition of the inhibitory metabolites into the PBPK model resulted in a more accurate prediction of DDIs (AUC and C max ratio) than that which only considered parent drug (bupropion) P450 inhibition. The simulation suggests that bupropion and its metabolites contribute to the DDI between bupropion and CYP2D6 substrates. The inhibitory potency from strong to weak is hydroxybupropion, threohydrobupropion, erythrohydrobupropion, and bupropion, respectively. The present bupropion PBPK model can be useful for predicting inhibition from bupropion in other clinical studies. This study highlights the need for caution and dosage adjustment when combining bupropion with medications metabolized by CYP2D6. It also demonstrates the feasibility of applying the PBPK approach to predict the DDI potential of drugs undergoing complex metabolism, especially in the DDI involving inhibitory

  17. 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

  18. A cyclic peptidic serine protease inhibitor

    DEFF Research Database (Denmark)

    Zhao, Baoyu; Xu, Peng; Jiang, Longguang

    2014-01-01

    Peptides are attracting increasing interest as protease inhibitors. Here, we demonstrate a new inhibitory mechanism and a new type of exosite interactions for a phage-displayed peptide library-derived competitive inhibitor, mupain-1 (CPAYSRYLDC), of the serine protease murine urokinase...... pocket, its carbonyl group aligning improperly relative to Ser195 and the oxyanion hole, explaining why the peptide is an inhibitor rather than a substrate. Substitution of the P1 Arg with novel unnatural Arg analogues with aliphatic or aromatic ring structures led to an increased affinity, depending......, in spite of a less favorable binding entropy and loss of a polar interaction. We conclude that increased flexibility of the peptide allows more favorable exosite interactions, which, in combination with the use of novel Arg analogues as P1 residues, can be used to manipulate the affinity and specificity...

  19. Molecular insights on analogs of HIV PR inhibitors toward HTLV-1 PR through QM/MM interactions and molecular dynamics studies: comparative structure analysis of wild and mutant HTLV-1 PR.

    Science.gov (United States)

    Selvaraj, Chandrabose; Singh, Poonam; Singh, Sanjeev Kumar

    2014-12-01

    Retroviruses HTLV-1 and HIV-1 are the primary causative agents of fatal adult T-cell leukemia and acquired immune deficiency syndrome (AIDS) disease. Both retroviruses are similar in characteristics mechanism, and it encodes for protease that mainly involved in the viral replication process. On the basis of the therapeutic success of HIV-1 PR inhibitors, the protease of HTLV-1 is mainly considered as a potential target for chemotherapy. At the same time, structural similarities in both enzymes that originate HIV PR inhibitors can also be an HTLV-1 PR inhibitor. But the expectations failed because of rejection of HIV PR inhibitors from the HTLV-1 PR binding pocket. In this present study, the reason for the HIV PR inhibitor rejection from the HTLV-1 binding site was identified through sequence analysis and molecular dynamics simulation method. Functional analysis of M37A mutation in HTLV PR clearly shows that the MET37 specificity and screening of potential inhibitors targeting MET37 is performed by using approved 90% similar HIV PR inhibitor compounds. From this approach, we report few compounds with a tendency to accept/donate electron specifically to an important site residue MET37 in HTLV-1 PR binding pocket. Copyright © 2014 John Wiley & Sons, Ltd.

  20. Crystal Structure of the Extended-Spectrum β-Lactamase PER-2 and Insights into the Role of Specific Residues in the Interaction with β-Lactams and β-Lactamase Inhibitors

    Science.gov (United States)

    Ruggiero, Melina; Kerff, Frédéric; Herman, Raphaël; Sapunaric, Frédéric; Galleni, Moreno; Gutkind, Gabriel; Charlier, Paulette; Sauvage, Eric

    2014-01-01

    PER-2 belongs to a small (7 members to date) group of extended-spectrum β-lactamases. It has 88% amino acid identity with PER-1 and both display high catalytic efficiencies toward most β-lactams. In this study, we determined the X-ray structure of PER-2 at 2.20 Å and evaluated the possible role of several residues in the structure and activity toward β-lactams and mechanism-based inhibitors. PER-2 is defined by the presence of a singular trans bond between residues 166 to 167, which generates an inverted Ω loop, an expanded fold of this domain that results in a wide active site cavity that allows for efficient hydrolysis of antibiotics like the oxyimino-cephalosporins, and a series of exclusive interactions between residues not frequently involved in the stabilization of the active site in other class A β-lactamases. PER β-lactamases might be included within a cluster of evolutionarily related enzymes harboring the conserved residues Asp136 and Asn179. Other signature residues that define these enzymes seem to be Gln69, Arg220, Thr237, and probably Arg/Lys240A (“A” indicates an insertion according to Ambler's scheme for residue numbering in PER β-lactamases), with structurally important roles in the stabilization of the active site and proper orientation of catalytic water molecules, among others. We propose, supported by simulated models of PER-2 in combination with different β-lactams, the presence of a hydrogen-bond network connecting Ser70-Gln69-water-Thr237-Arg220 that might be important for the proper activity and inhibition of the enzyme. Therefore, we expect that mutations occurring in these positions will have impacts on the overall hydrolytic behavior. PMID:25070104

  1. Protein C Inhibitor-A Novel Antimicrobial Agent

    NARCIS (Netherlands)

    Malmström, E.; Mörgelin, M.; Malmsten, M.; Johansson, L.; Norrby-Teglund, A.; Shannon, O.; Schmidtchen, A.; Meijers, J.C.M.; Herwald, H.

    2009-01-01

    Protein C inhibitor (PCI) is a heparin-binding serine proteinase inhibitor belonging to the family of serpin proteins. Here we describe that PCI exerts broad antimicrobial activity against bacterial pathogens. This ability is mediated by the interaction of PCI with lipid membranes, which

  2. Characterization of the virus-cell interactions by HIV-1 subtype C variants from an antiretroviral therapy-naïve subject with baseline resistance to the CCR5 inhibitor maraviroc

    DEFF Research Database (Denmark)

    Jakobsen, Martin Roelsgaard

    The CCR5 inhibitor maraviroc (MVC) exerts its antiviral activity by binding to- and altering the conformation of the CCR5 extracellular loops such that HIV-1 gp120 no longer recognizes CCR5. Viruses that have become resistant to MVC through long-term in vitro culture, or from treatment failure...... in vivo, can use the MVCbound form of CCR5 for HIV-1 entry via adaptive alterations in gp120. Partial baseline resistance to another CCR5 inhibitor through this mechanism, AD101, has been noted recently in one subject (1). Here, we identified and characterized envelope (Env) clones with baseline...

  3. Monoamine Oxidase Inhibitors (MAOIs)

    Science.gov (United States)

    ... health-medications/index.shtml. Accessed May 16, 2016. Hirsch M, et al. Monoamine oxidase inhibitors (MAOIs) for ... www.uptodate.com/home. Accessed May 16, 2016. Hirsch M, et al. Discontinuing antidepressant medications in adults. ...

  4. 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.

  5. Aromatase inhibitors in pediatrics.

    Science.gov (United States)

    Wit, Jan M; Hero, Matti; Nunez, Susan B

    2011-10-25

    Aromatase, an enzyme located in the endoplasmic reticulum of estrogen-producing cells, catalyzes the rate-limiting step in the conversion of androgens to estrogens in many tissues. The clinical features of patients with defects in CYP19A1, the gene encoding aromatase, have revealed a major role for this enzyme in epiphyseal plate closure, which has promoted interest in the use of inhibitors of aromatase to improve adult height. The availability of the selective aromatase inhibitors letrozole and anastrozole--currently approved as adjuvant therapy for breast cancer--have stimulated off-label use of aromatase inhibitors in pediatrics for the following conditions: hyperestrogenism, such as aromatase excess syndrome, Peutz-Jeghers syndrome, McCune-Albright syndrome and functional follicular ovarian cysts; hyperandrogenism, for example, testotoxicosis (also known as familial male-limited precocious puberty) and congenital adrenal hyperplasia; pubertal gynecomastia; and short stature and/or pubertal delay in boys. Current data suggest that aromatase inhibitors are probably effective in the treatment of patients with aromatase excess syndrome or testotoxicosis, partially effective in Peutz-Jeghers and McCune-Albright syndrome, but probably ineffective in gynecomastia. Insufficient data are available in patients with congenital adrenal hyperplasia or functional ovarian cysts. Although aromatase inhibitors appear effective in increasing adult height of boys with short stature and/or pubertal delay, safety concerns, including vertebral deformities, a decrease in serum HDL cholesterol levels and increase of erythrocytosis, are reasons for caution.

  6. 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.

  7. Cathepsin D inhibitors

    Directory of Open Access Journals (Sweden)

    M. Gacko

    2007-11-01

    Full Text Available Inhibitors of cathepsin D belong to chemical compounds that estrify carboxyl groups of the Asp33 and Asp231residues of its catalytic site, penta-peptides containing statin, i.e. the amino acid similar in structure to the tetraedric indirectproduct, and polypeptides found in the spare organs of many plants and forming permanent noncovalent complexes withcathepsin. Cathepsin D activity is also inhibited by alpha2-macroglobulin and antibodies directed against this enzyme.Methods used to determine the activity and concentration of these inhibitors and their analytical, preparative and therapeuticapplications are discussed.

  8. 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.

  9. Secreted and Transmembrane Wnt Inhibitors and Activators

    Science.gov (United States)

    Cruciat, Cristina-Maria; Niehrs, Christof

    2013-01-01

    Signaling by the Wnt family of secreted glycoproteins plays important roles in embryonic development and adult homeostasis. Wnt signaling is modulated by a number of evolutionarily conserved inhibitors and activators. Wnt inhibitors belong to small protein families, including sFRP, Dkk, WIF, Wise/SOST, Cerberus, IGFBP, Shisa, Waif1, APCDD1, and Tiki1. Their common feature is to antagonize Wnt signaling by preventing ligand–receptor interactions or Wnt receptor maturation. Conversely, the Wnt activators, R-spondin and Norrin, promote Wnt signaling by binding to Wnt receptors or releasing a Wnt-inhibitory step. With few exceptions, these antagonists and agonists are not pure Wnt modulators, but also affect additional signaling pathways, such as TGF-β and FGF signaling. Here we discuss their interactions with Wnt ligands and Wnt receptors, their role in developmental processes, as well as their implication in disease. PMID:23085770

  10. Transglutaminase inhibitor from milk

    NARCIS (Netherlands)

    Jong, G.A.H. de; Wijngaards, G.; Koppelman, S.J.

    2003-01-01

    Cross-linking experiments of skimmed bovine milk with bacterial transglutaminase isolated from Streptoverticillium mobaraense showed only some degree of formation of high-molecular-weight casein polymers. Studies on the nature of this phenomenon revealed that bovine milk contains an inhibitor of

  11. Inhibitors of histone demethylases

    DEFF Research Database (Denmark)

    Lohse, Brian; Kristensen, Jesper L; Kristensen, Line H

    2011-01-01

    Methylated lysines are important epigenetic marks. The enzymes involved in demethylation have recently been discovered and found to be involved in cancer development and progression. Despite the relative recent discovery of these enzymes a number of inhibitors have already appeared. Most of the i...

  12. ROS inhibitor N-acetyl-L-cysteine antagonizes the activity of proteasome inhibitors.

    Science.gov (United States)

    Halasi, Marianna; Wang, Ming; Chavan, Tanmay S; Gaponenko, Vadim; Hay, Nissim; Gartel, Andrei L

    2013-09-01

    NAC (N-acetyl-L-cysteine) is commonly used to identify and test ROS (reactive oxygen species) inducers, and to inhibit ROS. In the present study, we identified inhibition of proteasome inhibitors as a novel activity of NAC. Both NAC and catalase, another known scavenger of ROS, similarly inhibited ROS levels and apoptosis associated with H₂O₂. However, only NAC, and not catalase or another ROS scavenger Trolox, was able to prevent effects linked to proteasome inhibition, such as protein stabilization, apoptosis and accumulation of ubiquitin conjugates. These observations suggest that NAC has a dual activity as an inhibitor of ROS and proteasome inhibitors. Recently, NAC was used as a ROS inhibitor to functionally characterize a novel anticancer compound, piperlongumine, leading to its description as a ROS inducer. In contrast, our own experiments showed that this compound depicts features of proteasome inhibitors including suppression of FOXM1 (Forkhead box protein M1), stabilization of cellular proteins, induction of ROS-independent apoptosis and enhanced accumulation of ubiquitin conjugates. In addition, NAC, but not catalase or Trolox, interfered with the activity of piperlongumine, further supporting that piperlongumine is a proteasome inhibitor. Most importantly, we showed that NAC, but not other ROS scavengers, directly binds to proteasome inhibitors. To our knowledge, NAC is the first known compound that directly interacts with and antagonizes the activity of proteasome inhibitors. Taken together, the findings of the present study suggest that, as a result of the dual nature of NAC, data interpretation might not be straightforward when NAC is utilized as an antioxidant to demonstrate ROS involvement in drug-induced apoptosis.

  13. A preliminary electron microscopic investigation into the interaction between Aβ1-42 peptide and a novel nanoliposome- coupled retro-inverso peptide inhibitor, developed as a potential treatment for Alzheimer's disease

    Science.gov (United States)

    Sherer, M.; Fullwood, N. J.; Taylor, M.; Allsop, D.

    2015-10-01

    Alzheimer's disease (AD) is a progressive neurodegenerative condition that results in severe cognitive and functional decline in sufferers and for which there are currently no effective treatments to halt or reverse disease progression. AD is the most common form of dementia and age is the major risk factor for this disease. With worldwide population structures changing as increasing number of individuals survive into old age, there is urgent need for novel disease modifying treatments for this condition, which has profound effects upon sufferers in addition to those around them. Some of us have previously developed a peptide inhibitor of Aβ1-42 aggregation (RI-OR2-TAT) that has been shown to reduce Aβ1-42 pathology in vivo in mouse models of AD. ∼1690 copies of RI-OR2-TAT have been covalently attached to nanoliposome carrier particles forming Peptide Inhibitor NanoParticles (PINPs), and this study investigated the effect of PINPs upon Aβ1-42 aggregation at the molecular level. Our results show that PINPs are able to reduce Aβ1-42 aggregation and do so by binding early (oligomers) and late (fibrillar) stage aggregates. These results highlight the ability of PINPs to disrupt the formation of multiple Aβ1-42 aggregates capable of causing neurotoxicity and thus provide a strong case for PINPs to be carried forward into early stage clinical trials as a novel therapeutic option for the treatment of AD.

  14. A preliminary electron microscopic investigation into the interaction between Aβ1-42 peptide and a novel nanoliposome- coupled retro-inverso peptide inhibitor, developed as a potential treatment for Alzheimer's disease

    International Nuclear Information System (INIS)

    Sherer, M; Fullwood, N J; Taylor, M; Allsop, D

    2015-01-01

    Alzheimer's disease (AD) is a progressive neurodegenerative condition that results in severe cognitive and functional decline in sufferers and for which there are currently no effective treatments to halt or reverse disease progression. AD is the most common form of dementia and age is the major risk factor for this disease. With worldwide population structures changing as increasing number of individuals survive into old age, there is urgent need for novel disease modifying treatments for this condition, which has profound effects upon sufferers in addition to those around them. Some of us have previously developed a peptide inhibitor of Aβ 1-42 aggregation (RI-OR2-TAT) that has been shown to reduce Aβ 1-42 pathology in vivo in mouse models of AD. ∼1690 copies of RI-OR2-TAT have been covalently attached to nanoliposome carrier particles forming Peptide Inhibitor NanoParticles (PINPs), and this study investigated the effect of PINPs upon Aβ 1-42 aggregation at the molecular level. Our results show that PINPs are able to reduce Aβ 1-42 aggregation and do so by binding early (oligomers) and late (fibrillar) stage aggregates. These results highlight the ability of PINPs to disrupt the formation of multiple Aβ 1-42 aggregates capable of causing neurotoxicity and thus provide a strong case for PINPs to be carried forward into early stage clinical trials as a novel therapeutic option for the treatment of AD. (paper)

  15. Bicyclic peptide inhibitor of urokinase-type plasminogen activator

    DEFF Research Database (Denmark)

    Roodbeen, Renée; Jensen, Berit Paaske; Jiang, Longguang

    2013-01-01

    The development of protease inhibitors for pharmacological intervention has taken a new turn with the use of peptide-based inhibitors. Here, we report the rational design of bicyclic peptide inhibitors of the serine protease urokinase-type plasminogen activator (uPA), based on the established...... investigated the solution structures of the bicyclic peptide by NMR spectroscopy to map possible conformations. An X-ray structure of the bicyclic-peptide-uPA complex confirmed an interaction similar to that for the previous upain-1/upain-2-uPA complexes. These physical studies of the peptide...

  16. Acid corrosion inhibitor

    Energy Technology Data Exchange (ETDEWEB)

    Chen, N G

    1964-04-28

    An acid corrosion inhibitor is prepared by a 2-stage vacuum evaporation of effluents obtained from the ammonia columns of the coking oven plant. The effluent, leaving a scrubber in which the phenols are removed at a temperature of 98$C, passes through a quartz filter and flows into a heated chamber in which it is used for preheating a solution circulating through a vacuum unit, maintaining the temperature of the solution at 55$ to 60$C. The effluent enters a large tank in which it is boiled at 55$ to 60$C under 635 to 640 mm Hg pressure. Double evaporation of this solution yields a very effective acid corrosion inhibitor. Its corrosion-preventing effect is 97.9% compared with 90.1% for thiourea and 88.5% for urotropin under identical conditions.

  17. Benzoylurea Chitin Synthesis Inhibitors.

    Science.gov (United States)

    Sun, Ranfeng; Liu, Chunjuan; Zhang, Hao; Wang, Qingmin

    2015-08-12

    Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure-activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs.

  18. Immune checkpoint inhibitors for metastatic bladder cancer.

    Science.gov (United States)

    Massari, Francesco; Di Nunno, Vincenzo; Cubelli, Marta; Santoni, Matteo; Fiorentino, Michelangelo; Montironi, Rodolfo; Cheng, Liang; Lopez-Beltran, Anto; Battelli, Nicola; Ardizzoni, Andrea

    2018-03-01

    Chemotherapy has represented the standard therapy for unresectable or metastatic urothelial carcinoma for more than 20 years. The growing knowledge of the interaction between tumour and immune system has led to the advent of new classes of drugs, the immune-checkpoints inhibitors, which are intended to change the current scenario. To date, immunotherapy is able to improve the overall responses and survival. Moreover, thanks to its safety profile immune-checkpoint inhibitors could be proposed also to patients unfit for standard chemotherapy. No doubts that these agents have started a revolution expected for years, but despite this encouraging results it appears clear that not all subjects respond to these agents and requiring the development of reliable predictive response factors able to isolate patients who can more benefit from these treatments as well as new strategies aimed to improve immunotherapy clinical outcome. In this review we describe the active or ongoing clinical trials involving Programmed Death Ligand 1 (PD-L1), Programmed Death receptor 1 (PD-1) and Cytotoxic-T Lymphocyte Antigen 4 (CTLA 4) inhibitors in urothelial carcinoma focusing our attention on the developing new immune-agents and combination strategies with immune-checkpoint inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Use of selective-serotonin reuptake inhibitors and platelet aggregation inhibitors among individuals with co-occurring atherosclerotic cardiovascular disease and depression or anxiety

    Directory of Open Access Journals (Sweden)

    J Douglas Thornton

    2016-12-01

    Full Text Available Objective: Medications commonly used to treat heart disease, anxiety, and depression can interact resulting in an increased risk of bleeding, warranting a cautious approach in medical decision making. This retrospective, descriptive study examined the prevalence and the factors associated with the use of both selective-serotonin reuptake inhibitor and platelet aggregation inhibitor among individuals with co-occurring atherosclerotic cardiovascular disease and anxiety or depression. Methods: Respondents aged 22 years and older, alive throughout the study period, and diagnosed with co-occurring atherosclerotic cardiovascular disease and anxiety or depression (n = 1507 in years 2007 through 2013 of the Medical Expenditures Panel Survey were included. The use of treatment was grouped as follows: selective-serotonin reuptake inhibitor and platelet aggregation inhibitor, selective-serotonin reuptake inhibitor or platelet aggregation inhibitor, and neither selective-serotonin reuptake inhibitor nor platelet aggregation inhibitor. Results: Overall, 16.5% used both selective-serotonin reuptake inhibitor and platelet aggregation inhibitor, 61.2% used selective-serotonin reuptake inhibitor or platelet aggregation inhibitor, and 22.3% used neither selective-serotonin reuptake inhibitor nor platelet aggregation inhibitor. Respondents aged over 65 years (adjusted odds ratio = 1.93 (95% confidence interval = 1.08–3.45 and having a diagnosis of diabetes (adjusted odds ratio = 1.63 (95% confidence interval = 1.15–2.31 and hypertension (adjusted odds ratio = 1.84 (95% confidence interval = 1.04–3.27 were more likely to be prescribed the combination. Conclusion: The drug interaction was prevalent in patients who are already at higher risk of health disparities and worse outcomes thus requiring vigilant evaluation.

  20. ZL006, a small molecule inhibitor of PSD-95/nNOS interaction, does not induce antidepressant-like effects in two genetically predisposed rat models of depression and control animals.

    Directory of Open Access Journals (Sweden)

    Sandra Tillmann

    Full Text Available N-methyl-D-aspartate receptor (NMDA-R antagonists and nitric oxide inhibitors have shown promising efficacy in depression but commonly induce adverse events. To circumvent these, a more indirect disruption of the nitric oxide synthase/postsynaptic density protein 95 kDa complex at the NMDA-R has been proposed. This disruption can be achieved using small molecule inhibitors such as ZL006, which has attracted attention as ischemic stroke therapy in rodents and has been proposed as a potential novel treatment for depression. Based on this, our aim was to translate these findings to animal models of depression to elucidate antidepressant-like properties in more detail. In the present study, we administered ZL006 to two established animal models of depression and control rodents. Following treatment, we measured locomotion in the Open Field and depressive-like behavior in the Forced Swim Test and Tail Suspension Test. Our experimental designs included the use of different species (rats, mice, strains (Flinders Sensitive Line rats, Flinders Resistant Line rats, Wistar Kyoto rats, Wistar Hanover rats, Sprague Dawley rats, B6NTac mice, routes of administration (intraperitoneal, intracerebroventricular, times of administration (single injection, repeated injections, treatment regimens (acute, sustained, and doses (5, 10, 15, 50 mg/kg. ZL006 did not affect behavior in any of the described settings. On a molecular level, ZL006 significantly reduced total nitrate/nitrite concentrations in the cerebellum, supporting that it is capable of reducing nitric oxide metabolites in the brain. Future studies using different experimental parameters are needed to further investigate the behavioral profile of ZL006.

  1. DGAT inhibitors for obesity.

    Science.gov (United States)

    Matsuda, Daisuke; Tomoda, Hiroshi

    2007-10-01

    Obesity is characterized by the accumulation of triacylglycerol in adipocytes. Diacylglycerol acyltransferase (DGAT) catalyzes the final reaction of triacylgycerol synthesis. Two isozymes of DGAT, DGAT1 and DGAT2, have been reported. Increased DGAT2 activity has a role in steatosis, while DGAT1 plays a role in very (V)LDL synthesis; increased plasma VLDL concentrations may promote obesity and thus DGAT1 is considered a potential therapeutic target of inhibition for obesity control. Several DGAT inhibitors of natural and synthetic origin have been reported, and their future prospect as anti-obesity drugs is discussed in this review.

  2. Pulmonary Toxicity of Cholinesterase Inhibitors

    National Research Council Canada - National Science Library

    Hilmas, Corey; Adler, Michael; Baskin, Steven I; Gupta, Ramesh C

    2006-01-01

    .... Whereas nerve agents were produced primarily for military deployment, other cholinesterase inhibitors were used for treating conditions such as myasthenia gravis and as pretreaunents for nerve agent exposure...

  3. The effect of angiotensin-converting-enzyme inhibitors on progression of advanced polycystic kidney disease

    DEFF Research Database (Denmark)

    Jafar, Tazeen H; Stark, Paul C; Schmid, Christopher H

    2005-01-01

    BACKGROUND: It is not known whether angiotensin-converting-enzyme (ACE) inhibitors slow the progression of polycystic kidney disease (PKD). We performed a patient-level meta-analysis to compare the effect of antihypertensive regimens, including ACE inhibitors, to those without ACE inhibitors...... of doubling of baseline serum creatinine or onset of kidney failure). We also performed multivariable linear regression and Cox proportional hazards analyses. Based on previous findings, we searched for interactions between the treatment effect (effect of ACE inhibitors vs. controls) and baseline urine......%) in the ACE inhibitor group and 30 patients (41%) in the control group (P= 0.17). ACE inhibitors had a greater effect on lowering urine protein excretion and slowing kidney disease progression in patients with higher levels of baseline urine protein excretion (interaction P

  4. 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.

  5. Polyphenol Compound as a Transcription Factor Inhibitor

    Directory of Open Access Journals (Sweden)

    Seyeon Park

    2015-10-01

    Full Text Available A target-based approach has been used to develop novel drugs in many therapeutic fields. In the final stage of intracellular signaling, transcription factor–DNA interactions are central to most biological processes and therefore represent a large and important class of targets for human therapeutics. Thus, we focused on the idea that the disruption of protein dimers and cognate DNA complexes could impair the transcriptional activation and cell transformation regulated by these proteins. Historically, natural products have been regarded as providing the primary leading compounds capable of modulating protein–protein or protein-DNA interactions. Although their mechanism of action is not fully defined, polyphenols including flavonoids were found to act mostly as site-directed small molecule inhibitors on signaling. There are many reports in the literature of screening initiatives suggesting improved drugs that can modulate the transcription factor interactions responsible for disease. In this review, we focus on polyphenol compound inhibitors against dimeric forms of transcription factor components of intracellular signaling pathways (for instance, c-jun/c-fos (Activator Protein-1; AP-1, c-myc/max, Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB and β-catenin/T cell factor (Tcf.

  6. Polyphenol Compound as a Transcription Factor Inhibitor.

    Science.gov (United States)

    Park, Seyeon

    2015-10-30

    A target-based approach has been used to develop novel drugs in many therapeutic fields. In the final stage of intracellular signaling, transcription factor-DNA interactions are central to most biological processes and therefore represent a large and important class of targets for human therapeutics. Thus, we focused on the idea that the disruption of protein dimers and cognate DNA complexes could impair the transcriptional activation and cell transformation regulated by these proteins. Historically, natural products have been regarded as providing the primary leading compounds capable of modulating protein-protein or protein-DNA interactions. Although their mechanism of action is not fully defined, polyphenols including flavonoids were found to act mostly as site-directed small molecule inhibitors on signaling. There are many reports in the literature of screening initiatives suggesting improved drugs that can modulate the transcription factor interactions responsible for disease. In this review, we focus on polyphenol compound inhibitors against dimeric forms of transcription factor components of intracellular signaling pathways (for instance, c-jun/c-fos (Activator Protein-1; AP-1), c-myc/max, Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and β-catenin/T cell factor (Tcf)).

  7. Discovery and X-ray crystallographic analysis of a spiropiperidine iminohydantoin inhibitor of beta-secretase.

    Science.gov (United States)

    Barrow, James C; Stauffer, Shaun R; Rittle, Kenneth E; Ngo, Phung L; Yang, ZhiQiang; Selnick, Harold G; Graham, Samuel L; Munshi, Sanjeev; McGaughey, Georgia B; Holloway, M Katharine; Simon, Adam J; Price, Eric A; Sankaranarayanan, Sethu; Colussi, Dennis; Tugusheva, Katherine; Lai, Ming-Tain; Espeseth, Amy S; Xu, Min; Huang, Qian; Wolfe, Abigail; Pietrak, Beth; Zuck, Paul; Levorse, Dorothy A; Hazuda, Daria; Vacca, Joseph P

    2008-10-23

    A high-throughput screen at 100 microM inhibitor concentration for the BACE-1 enzyme revealed a novel spiropiperidine iminohydantoin aspartyl protease inhibitor template. An X-ray cocrystal structure with BACE-1 revealed a novel mode of binding whereby the inhibitor interacts with the catalytic aspartates via bridging water molecules. Using the crystal structure as a guide, potent compounds with good brain penetration were designed.

  8. 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)

  9. Mechanism of action and efficacy of RX-111, a thieno[2,3-c]pyridine derivative and small molecule inhibitor of protein interaction with glycosaminoglycans (SMIGs), in delayed-type hypersensitivity, TNBS-induced colitis and experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Harris, Nicholas; Koppel, Juraj; Zsila, Ferenc; Juhas, Stefan; Il'kova, Gabriela; Kogan, Faina Yurgenzon; Lahmy, Orly; Wildbaum, Gizi; Karin, Nathan; Zhuk, Regina; Gregor, Paul

    2016-04-01

    Elucidate the mechanism of action of the small molecule inhibitor of protein binding to glycosaminoglycans, RX-111 and assay its anti-inflammatory activity in animal models of inflammatory disease. The glycosaminoglycan, heparin, was used in the mechanism of action study of RX-111. Human T lymphocytes and umbilical vein endothelial cells were used to assay the in vitro activity of RX-111. Mouse and rat models of disease were used to assay the anti-inflammatory activity of RX-111 in vivo. Circular dichroism and UV/Vis absorption spectroscopy were used to study the binding of RX-111 to the glycosaminoglycan, heparin. T lymphocyte rolling on endothelial cells under shear flow was used to assay RX-111 activity in vitro. Delayed-type hypersensitivity (DTH) and tri-nitrobenzene sulfonic acid (TNBS)-induced colitis in mice and experimental autoimmune encephalomyelitis (EAE) in rats were used to assay anti-inflammatory activity of RX-111 in vivo. RX-111 was shown to bind directly to heparin. It inhibited leukocyte rolling on endothelial cells under shear flow and reduced inflammation in the mouse model of DTH. RX-111 was efficacious in the mouse model of inflammatory bowel disease, TNBS-induced colitis and the rat model of multiple sclerosis, EAE. RX-111 exercises its broad spectrum anti-inflammatory activity by a singular mechanism of action, inhibition of protein binding to the cell surface GAG, heparan sulfate. RX-111 and related thieno[2,3-c]pyridine derivatives are potential therapeutics for the treatment of inflammatory and autoimmune diseases.

  10. 1,4-Bis(5-(naphthalen-1-yl)thiophen-2-yl)naphthalene, a small molecule, functions as a novel anti-HIV-1 inhibitor targeting the interaction between integrase and cellular Lens epithelium-derived growth factor.

    Science.gov (United States)

    Gu, Wan-gang; Ip, Denis Tsz-Ming; Liu, Si-jie; Chan, Joseph H; Wang, Yan; Zhang, Xuan; Zheng, Yong-tang; Wan, David Chi-Cheong

    2014-04-25

    Translocation of viral integrase (IN) into the nucleus is a critical precondition of integration during the life cycle of HIV, a causative agent of Acquired Immunodeficiency Syndromes (AIDS). As the first discovered cellular factor to interact with IN, Lens epithelium-derived growth factor (LEDGF/p75) plays an important role in the process of integration. Disruption of the LEDGF/p75-IN interaction has provided a great interest for anti-HIV agent discovery. In this work, we reported that one small molecular compound, 1,4-bis(5-(naphthalen-1-yl)thiophen-2-yl)naphthalene(Compound 15), potently inhibit the IN-LEDGF/p75 interaction and affect the HIV-1 IN nuclear distribution at 1 μM. The putative binding mode of Compound 15 was constructed by a molecular docking simulation to provide structural insights into the ligand-binding mechanism. Compound 15 suppressed viral replication by measuring p24 antigen production in HIV-1IIIB acute infected C8166 cells with EC50 value of 11.19 μM. Compound 15 might supply useful structural information for further anti-HIV agent discovery. Copyright © 2014. Published by Elsevier Ireland Ltd.

  11. Biological abatement of cellulase inhibitors

    Science.gov (United States)

    Bio-abatement uses a fungus to metabolize and remove fermentation inhibitors. To determine whether bio-abatement could alleviate enzyme inhibitor effects observed in biomass liquors after pretreatment, corn stover at 10% (w/v) solids was pretreated with either dilute acid or liquid hot water. The ...

  12. 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...

  13. Corrosion inhibitors. Manufacture and technology

    International Nuclear Information System (INIS)

    Ranney, M.W.

    1976-01-01

    Detailed information is presented relating to corrosion inhibitors. Areas covered include: cooling water, boilers and water supply plants; oil well and refinery operations; fuel and lubricant additives for automotive use; hydraulic fluids and machine tool lubes; grease compositions; metal surface treatments and coatings; and general processes for corrosion inhibitors

  14. 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.

  15. Corrosion protection with eco-friendly inhibitors

    Science.gov (United States)

    Shahid, Muhammad

    2011-12-01

    Corrosion occurs as a result of the interaction of a metal with its environment. The extent of corrosion depends on the type of metal, the existing conditions in the environment and the type of aggressive ions present in the medium. For example, CO3-2 and NO-3 produce an insoluble deposit on the surface of iron, resulting in the isolation of metal and consequent decrease of corrosion. On the other hand, halide ions are adsorbed selectively on the metal surface and prevent formation of the oxide phase on the metal surface, resulting in continuous corrosion. Iron, aluminum and their alloys are widely used, both domestically and industrially. Linear alkylbenzene and linear alkylbenzene sulfonate are commonly used as detergents. They have also been found together in waste water. It is claimed that these chemicals act as inhibitors for stainless steel and aluminum. Release of toxic gases as a result of corrosion in pipelines may lead in certain cases to air pollution and possible health hazards. Therefore, there are two ways to look at the relationship between corrosion and pollution: (i) corrosion of metals and alloys due to environmental pollution and (ii) environmental pollution as a result of corrosion protection. This paper encompasses the two scenarios and possible remedies for various cases, using 'green' inhibitors obtained either from plant extracts or from pharmaceutical compounds. In the present study, the effect of piperacillin sodium as a corrosion inhibitor for mild steel was investigated using a weight-loss method as well as a three-electrode dc electrochemical technique. It was found that the corrosion rate decreased as the concentration of the inhibitor increased up to 9×10-4 M 93% efficiency was exhibited at this concentration.

  16. Relative contributions of the major human CYP450 to the metabolism of icotinib and its implication in prediction of drug-drug interaction between icotinib and CYP3A4 inhibitors/inducers using physiologically based pharmacokinetic modeling.

    Science.gov (United States)

    Chen, Jia; Liu, Dongyang; Zheng, Xin; Zhao, Qian; Jiang, Ji; Hu, Pei

    2015-06-01

    Icotinib is an anticancer drug, but relative contributions of CYP450 have not been identified. This study was carried out to identify the contribution percentage of CYP450 to icotinib and use the results to develop a physiologically based pharmacokinetic (PBPK) model, which can help to predict drug-drug interaction (DDI). Human liver microsome (HLM) and supersome using relative activity factor (RAF) were employed to determine the relative contributions of the major human P450 to the net hepatic metabolism of icotinib. These values were introduced to develop a PBPK model using SimCYP. The model was validated by the observed data in a Phase I clinical trial in Chinese healthy subjects. Finally, the model was used to simulate the DDI with ketoconazole or rifampin. Final contribution of CYP450 isoforms determined by HLM showed that CYP3A4 provided major contributions to the metabolism of icotinib. The percentage contributions of the P450 to the net hepatic metabolism of icotinib were determined by HLM inhibition assay and RAF. The AUC ratio under concomitant use of ketoconazole and rifampin was 3.22 and 0.55, respectively. Percentage of contribution of CYP450 to icotinib metabolism was calculated by RAF. The model has been proven to fit the observed data and is used in predicting icotinib-ketoconazole/rifampin interaction.

  17. 2D MI-DRAGON: a new predictor for protein-ligands interactions and theoretic-experimental studies of US FDA drug-target network, oxoisoaporphine inhibitors for MAO-A and human parasite proteins.

    Science.gov (United States)

    Prado-Prado, Francisco; García-Mera, Xerardo; Escobar, Manuel; Sobarzo-Sánchez, Eduardo; Yañez, Matilde; Riera-Fernandez, Pablo; González-Díaz, Humberto

    2011-12-01

    There are many pairs of possible Drug-Proteins Interactions that may take place or not (DPIs/nDPIs) between drugs with high affinity/non-affinity for different proteins. This fact makes expensive in terms of time and resources, for instance, the determination of all possible ligands-protein interactions for a single drug. In this sense, we can use Quantitative Structure-Activity Relationships (QSAR) models to carry out rational DPIs prediction. Unfortunately, almost all QSAR models predict activity against only one target. To solve this problem we can develop multi-target QSAR (mt-QSAR) models. In this work, we introduce the technique 2D MI-DRAGON a new predictor for DPIs based on two different well-known software. We use the software MARCH-INSIDE (MI) to calculate 3D structural parameters for targets and the software DRAGON was used to calculated 2D molecular descriptors all drugs showing known DPIs present in the Drug Bank (US FDA benchmark dataset). Both classes of parameters were used as input of different Artificial Neural Network (ANN) algorithms to seek an accurate non-linear mt-QSAR predictor. The best ANN model found is a Multi-Layer Perceptron (MLP) with profile MLP 21:21-31-1:1. This MLP classifies correctly 303 out of 339 DPIs (Sensitivity = 89.38%) and 480 out of 510 nDPIs (Specificity = 94.12%), corresponding to training Accuracy = 92.23%. The validation of the model was carried out by means of external predicting series with Sensitivity = 92.18% (625/678 DPIs; Specificity = 90.12% (730/780 nDPIs) and Accuracy = 91.06%. 2D MI-DRAGON offers a good opportunity for fast-track calculation of all possible DPIs of one drug enabling us to re-construct large drug-target or DPIs Complex Networks (CNs). For instance, we reconstructed the CN of the US FDA benchmark dataset with 855 nodes 519 drugs+336 targets). We predicted CN with similar topology (observed and predicted values of average distance are equal to 6.7 vs. 6.6). These CNs can be used to explore

  18. Phospholipid Binding Protein C Inhibitor (PCI) Is Present on Microparticles Generated In Vitro and In Vivo

    Science.gov (United States)

    Einfinger, Katrin; Badrnya, Sigrun; Furtmüller, Margareta; Handschuh, Daniela; Lindner, Herbert; Geiger, Margarethe

    2015-01-01

    Protein C inhibitor is a secreted, non-specific serine protease inhibitor with broad protease reactivity. It binds glycosaminoglycans and anionic phospholipids, which can modulate its activity. Anionic phospholipids, such as phosphatidylserine are normally localized to the inner leaflet of the plasma membrane, but are exposed on activated and apoptotic cells and on plasma membrane-derived microparticles. In this report we show by flow cytometry that microparticles derived from cultured cells and activated platelets incorporated protein C inhibitor during membrane blebbing. Moreover, protein C inhibitor is present in/on microparticles circulating in normal human plasma as judged from Western blots, ELISAs, flow cytometry, and mass spectrometry. These plasma microparticles are mainly derived from megakaryocytes. They seem to be saturated with protein C inhibitor, since they do not bind added fluorescence-labeled protein C inhibitor. Heparin partially removed microparticle-bound protein C inhibitor, supporting our assumption that protein C inhibitor is bound via phospholipids. To assess the biological role of microparticle-bound protein C inhibitor we performed protease inhibition assays and co-precipitated putative binding partners on microparticles with anti-protein C inhibitor IgG. As judged from amidolytic assays microparticle-bound protein C inhibitor did not inhibit activated protein C or thrombin, nor did microparticles modulate the activity of exogenous protein C inhibitor. Among the proteins co-precipitating with protein C inhibitor, complement factors, especially complement factor 3, were most striking. Taken together, our data do not support a major role of microparticle-associated protein C inhibitor in coagulation, but rather suggest an interaction with proteins of the complement system present on these phospholipid vesicles. PMID:26580551

  19. [ACE inhibitors and the kidney].

    Science.gov (United States)

    Hörl, W H

    1996-01-01

    Treatment with ACE inhibitors results in kidney protection due to reduction of systemic blood pressure, intraglomerular pressure, an antiproliferative effect, reduction of proteinuria and a lipid-lowering effect in proteinuric patients (secondary due to reduction of protein excretion). Elderly patients with diabetes melitus, coronary heart disease or peripheral vascular occlusion are at risk for deterioration of kidney function due to a high frequency of renal artery stenosis in these patients. In patients with renal insufficiency dose reduction of ACE inhibitors is necessary (exception: fosinopril) but more important is the risk for development of hyperkalemia. Patients at risk for renal artery stenosis and patients pretreated with diuretics should receive a low ACE inhibitor dosage initially ("start low - go slow"). For compliance reasons once daily ACE inhibitor dosage is recommended.

  20. Solution structure of the Grb2 SH2 domain complexed with a high-affinity inhibitor

    International Nuclear Information System (INIS)

    Ogura, Kenji; Shiga, Takanori; Yokochi, Masashi; Yuzawa, Satoru; Burke, Terrence R.; Inagaki, Fuyuhiko

    2008-01-01

    The solution structure of the growth factor receptor-bound protein 2 (Grb2) SH2 domain complexed with a high-affinity inhibitor containing a non-phosphorus phosphate mimetic within a macrocyclic platform was determined by nuclear magnetic resonance (NMR) spectroscopy. Unambiguous assignments of the bound inhibitor and intermolecular NOEs between the Grb2 SH2 domain and the inhibitor was accomplished using perdeuterated Grb2 SH2 protein. The well-defined solution structure of the complex was obtained and compared to those by X-ray crystallography. Since the crystal structure of the Grb2 SH2 domain formed a domain-swapped dimer and several inhibitors were bound to a hinge region, there were appreciable differences between the solution and crystal structures. Based on the binding interactions between the inhibitor and the Grb2 SH2 domain in solution, we proposed a design of second-generation inhibitors that could be expected to have higher affinity

  1. Inhibition of neuraminidase by Ganoderma triterpenoids and implications for neuraminidase inhibitor design

    Science.gov (United States)

    Zhu, Qinchang; Bang, Tran Hai; Ohnuki, Koichiro; Sawai, Takashi; Sawai, Ken; Shimizu, Kuniyoshi

    2015-01-01

    Neuraminidase (NA) inhibitors are the dominant antiviral drugs for treating influenza in the clinic. Increasing prevalence of drug resistance makes the discovery of new NA inhibitors a high priority. Thirty-one triterpenoids from the medicinal mushroom Ganoderma lingzhi were analyzed in an in vitro NA inhibition assay, leading to the discovery of ganoderic acid T-Q and TR as two inhibitors of H5N1 and H1N1 NAs. Structure-activity relationship studies revealed that the corresponding triterpenoid structure is a potential scaffold for the design of NA inhibitors. Using these triterpenoids as probes we found, through further in silico docking and interaction analysis, that interactions with the amino-acid residues Arg292 and/or Glu119 of NA are critical for the inhibition of H5N1 and H1N1. These findings should prove valuable for the design and development of NA inhibitors. PMID:26307417

  2. What Are The Benefits In The Association Of SGLT2 Inhibitors And Other Drugs?

    Directory of Open Access Journals (Sweden)

    Deici Aparecida Gomes Rodrigues

    2017-11-01

    Full Text Available The SGLT2 inhibitors are a class of drugs that blocks the sodium-glucose co-transport, which is responsible for 90% of the nephron glucose. Objective: To show the benefits of the SGLT2 inhibitors in monotherapy and in association with other drugs. Results: The association of SGLT2 inhibitors and other drugs has shown several additional benefits after their interaction, including weight loss, reduction of body fat, reduction of triglycerides level, decrease of glycated hemoglobin, decrease in postprandial glucose level, reduction of arterial pressure, decrease of hypoglycemia risk and improvement of glucose metabolism. Therefore, this is a promising interaction for type 2 diabetes.

  3. Barley alpha-amylase/subtilisin inhibitor: structure, biophysics and protein engineering

    DEFF Research Database (Denmark)

    Nielsen, P.K.; Bønsager, Birgit Christine; Fukuda, Kenji

    2004-01-01

    Bifunctional alpha-amylase/subtilisin inhibitors have been implicated in plant defence and regulation of endogenous alpha-amylase action. The barley alpha-amylase/subtilisin inhibitor (BASI) inhibits the barley alpha-amylase 2 (AMY2) and subtilisin-type serine proteases. BASI belongs to the Kunitz...... Ca2+-modulated kinetics of the AMY2/BASl interaction and found that the complex formation involves minimal structural changes. The modulation of the interaction by calcium ions makes it unique among the currently known binding mechanisms of proteinaceous alpha-amylase inhibitors....

  4. In silico development of new acetylcholinesterase inhibitors.

    Science.gov (United States)

    Pascoini, A L; Federico, L B; Arêas, A L F; Verde, B A; Freitas, P G; Camps, I

    2018-04-19

    In this work, we made use of fragment-based drug design (FBDD) and de novo design to obtain more powerful acetylcholinesterase (AChE) inhibitors. AChE is associated with Alzheimer's disease (AD). It was found that the cholinergic pathways in the cerebral cortex are compromised in AD and the accompanying cholinergic deficiency contributes to the cognitive deterioration of AD patients. In the FBDD approach, fragments are docked into the active site of the protein. As fragments are molecular groups with a low number of atoms, it is possible to study their interaction with localized amino acids. Once the interactions are measured, the fragments are organized by affinity and then linked together to form new molecules with a high degree of interaction with the active site. In the other approach, we used the de novo design technique starting from reference drugs used in the AD treatment. These drugs were broken into fragments (seeds). In the growing strategy, fragments were added to each seed, growing new molecules. In the linking strategy, two or more separated seeds were linked with different fragments. Both strategies combined produced a library of more than 2 million compounds. This library was filtered using absorption, distribution, metabolism, and excretion properties. The resulting library with around six thousand compounds was filtered again. In this case, structures with Tanimoto coefficients >.85 were discarded. The final library with 1500 compounds was submitted to docking studies. As a result, 10 compounds with better interaction energy than the reference drugs were obtained.

  5. Drug interactions in primary health care in the George subdistrict ...

    African Journals Online (AJOL)

    2012-02-15

    Feb 15, 2012 ... Drug-drug interactions are a recognised cause of morbidity and mortality ..... or fatal if the interaction increases toxicity or reduces the intended effect of the ... antihypertensive effect of angiotensin-converting enzyme inhibitors ...

  6. Metal corrosion inhibitors and ecology

    International Nuclear Information System (INIS)

    Krasts, H.; Svarce, J.; Berge, B.

    1999-01-01

    The use of metal corrosion inhibitors in water is one of the cheapest method to protect metals against corrosion. However, the used inhibitors can come to surface water in the course of time and can become as source of environmental pollution. It is important to co-ordinate amount of substances in the elaborated inhibitors not only with demands for metal protection, but also with demands for quality of surface water and drinking water according to normative statements: 3.5 mg/l (as PO 4 ) for hexametaphosphate, tripolyphosphate and phosphonate; 40 mg/l (as SiO 2 for silicate, up to 1 mg/l for CU 2+ ; up to 5 mg/l for Zn 2+ ; up to 1 mg/l for B; up to 0.5 mg/l for Mo 2+ . The examples of the elaborated inhibitors are given. Many organic substances can be used as corrosion inhibitors, but there is shortage of standard methods for their analysis in water in Latvia. Removing of salt's deposits from boilers needs elaboration of a separate normative statement for dispersing waste water which content chloride at high concentration and heavy metals. (authors)

  7. Screening of inhibitors for remediation of asphaltene deposits: Experimental and modeling study

    Directory of Open Access Journals (Sweden)

    Mehdi Madhi

    2018-06-01

    Full Text Available One of the most severe problems during production from heavy crude oil reservoirs is the formation of asphaltene precipitation and as a result deposition in the tubing, surface facilities and near wellbore region which causes oil production and permeability reduction in addition to rock wettability alteration in the reservoir. So one of the economical ways to prevent such incidents is using the chemicals which are called asphaltene inhibitor.In this study, the influence of three commercial inhibitors, namely; Cetyl Terimethyl Ammonium Bromide (CTAB, Sodium Dodecyl Sulfate (SDS, Triton X-100 and four non-commercial (Benzene, Benzoic Acid, Salicylic Acid, Naphthalene inhibitors on two Iranian crude oils were investigated. This study extends previous works and contributes toward the better understanding of interactions between asphaltene and inhibitor. Effect of functional groups and structure of inhibitors on asphaltene precipitation were studied and it seems clear that the nature and polarity of asphaltene (structure and amount of impurities presented has a significant impact on the selection of inhibitors. asphaltene dispersant tests and Core flood tests were designed for evaluation of inhibitors in static and dynamic conditions. The results revealed distinguished mechanisms for asphaltene solubilization/dispersion (such as hydrogen bonding, π–π interaction and acid-base interaction and influence of additional side group (OH on inhibition power of inhibitor.During the experiments, it was found that increasing inhibitor concentration may lead to the self-assembly of inhibitor and declining of asphaltene stabilization. So, finding optimum concentration of inhibitor with high efficiency and available at a reasonable price is very important. The results suggest that 600 ppm of CTAB and 300 ppm of SDS were approximately optimum concentrations for the studied crude oils. One of the most important findings that differ from previous studies is the

  8. HTCC: Broad Range Inhibitor of Coronavirus Entry.

    Directory of Open Access Journals (Sweden)

    Aleksandra Milewska

    Full Text Available To date, six human coronaviruses have been known, all of which are associated with respiratory infections in humans. With the exception of the highly pathogenic SARS and MERS coronaviruses, human coronaviruses (HCoV-NL63, HCoV-OC43, HCoV-229E, and HCoV-HKU1 circulate worldwide and typically cause the common cold. In most cases, infection with these viruses does not lead to severe disease, although acute infections in infants, the elderly, and immunocompromised patients may progress to severe disease requiring hospitalization. Importantly, no drugs against human coronaviruses exist, and only supportive therapy is available. Previously, we proposed the cationically modified chitosan, N-(2-hydroxypropyl-3-trimethylammonium chitosan chloride (HTCC, and its hydrophobically-modified derivative (HM-HTCC as potent inhibitors of the coronavirus HCoV-NL63. Here, we show that HTCC inhibits interaction of a virus with its receptor and thus blocks the entry. Further, we demonstrate that HTCC polymers with different degrees of substitution act as effective inhibitors of all low-pathogenic human coronaviruses.

  9. Lonafarnib is a potential inhibitor for neovascularization.

    Directory of Open Access Journals (Sweden)

    Linlin Sun

    Full Text Available Atherosclerosis is a common cardiovascular disease that involves the build-up of plaque on the inner walls of the arteries. Intraplaque neovacularization has been shown to be essential in the pathogenesis of atherosclerosis. Previous studies showed that small-molecule compounds targeting farnesyl transferase have the ability to prevent atherosclerosis in apolipoprotein E-deficient mice, but the underlying mechanism remains to be elucidated. In this study, we found that lonafarnib, a specific inhibitor of farnesyl transferase, elicits inhibitory effect on vascular endothelial capillary assembly in vitro in a dose-dependent manner. In addition, we showed that lonafarnib treatment led to a dose-dependent decrease in scratch wound closure in vitro, whereas it had little effect on endothelial cell proliferation. These data indicate that lonafarnib inhibits neovascularization via directly targeting endothelial cells and disturbing their motility. Moreover, we demonstrated that pharmacological inhibition of farnesyl transferase by lonafarnib significantly impaired centrosome reorientation toward the leading edge of endothelial cells. Mechanistically, we found that the catalytic β subunit of farnesyl transferase associated with a cytoskeletal protein important for the establishment and maintenance of cell polarity. Additionally, we showed that lonafarnib remarkably inhibited the expression of the cytoskeletal protein and interrupted its interaction with farnesyl transferase. Our findings thus offer novel mechanistic insight into the protective effect of farnesyl transferase inhibitors on atherosclerosis and provide encouraging evidence for the potential use of this group of agents in inhibiting plaque neovascularization.

  10. Proton Pump Inhibitors and Risk of Rhabdomyolysis.

    Science.gov (United States)

    Duncan, Scott J; Howden, Colin W

    2017-01-01

    Proton pump inhibitors (PPIs) have been associated with a variety of adverse events, although the level of evidence for many of these is weak at best. Recently, one national regulatory authority has mandated a change to the labeling of one PPI based on reports of possible associated rhabdomyolysis. Thus, in this review we summarize the available evidence linking PPI use with rhabdomyolysis. The level of evidence is insufficient to establish a causal relationship and is largely based on sporadic case reports. In general, patients with suspected PPI-associated rhabdomyolysis have not been re-challenged with a PPI after recovery. The mechanism whereby PPIs might have been associated with rhabdomyolysis is unclear but possibly related to interaction with concomitantly administered drugs such as HMG-CoA reductase inhibitors (statins). For patients with rhabdomyolysis, a careful search must be made for possible etiological factors. In patients who recover from an episode of possible PPI-related rhabdomyolysis but do not have a genuine requirement for PPI treatment, the PPI should not be re-introduced. For those with a definite indication for ongoing PPI treatment, the PPI can be re-introduced but should preferably not be administered with a statin.

  11. Synthesis of Novel Chalcones as Acetylcholinesterase Inhibitors

    Directory of Open Access Journals (Sweden)

    Thanh-Dao Tran

    2016-07-01

    Full Text Available A new series of benzylaminochalcone derivatives with different substituents on ring B were synthesized and evaluated as inhibitors of acetylcholinesterase. The study is aimed at identification of novel benzylaminochalcones capable of blocking acetylcholinesterase activity for further development of an approach to Alzheimer’s disease treatment. These compounds were produced in moderate to good yields via Claisen-Schmidt condensation and subjected to an in vitro acetylcholinesterase inhibition assay, using Ellman’s method. The in silico docking procedure was also employed to identify molecular interactions between the chalcone compounds and the enzyme. Compounds with ring B bearing pyridin-4-yl, 4-nitrophenyl, 4-chlorophenyl and 3,4-dimethoxyphenyl moieties were discovered to exhibit significant inhibitory activities against acetylcholinesterase, with IC50 values ranging from 23 to 39 µM. The molecular modeling studies are consistent with the hypothesis that benzylaminochalcones could exert their effects as dual-binding-site acetylcholinesterase inhibitors, which might simultaneously enhance cholinergic neurotransmission and inhibit β-amyloid aggregation through binding to both catalytic and peripheral sites of the enzyme. These derivatives could be further developed to provide novel leads for the discovery of new anti-Alzheimer drugs in the future.

  12. Positron emitter labeled enzyme inhibitors

    International Nuclear Information System (INIS)

    Fowler, J.S.; MacGregor, R.R.; Wolf, A.P.; Langstrom, B.

    1990-01-01

    This invention involves a new strategy for imagining and mapping enzyme activity in the living human and animal body using positron emitter-labeled suicide enzyme inactivators or inhibitors which become covalently bound to the enzyme as a result of enzymatic catalysis. Two such suicide inactivators for monoamine oxidase have been labeled with carbon-11 and used to map the enzyme subtypes in the living human and animal body using PET. By using positron emission tomography to image the distribution of radioactivity produced by the body penetrating radiation emitted by carbon-11, a map of functionally active monoamine oxidase activity is obtained. Clorgyline and L-deprenyl are suicide enzyme inhibitors and irreversibly inhibit monoamine oxidase. When these inhibitors are labeled with carbon-11 they provide selective probes for monoamine oxidase localization and reactivity in vivo using positron emission tomography

  13. ROCK inhibitors in ocular disease

    Directory of Open Access Journals (Sweden)

    Eva Halasz

    2016-12-01

    Full Text Available Rho kinases (ROCKs have a crucial role in actin-cytoskeletal reorganization and thus are involved in broad aspects of cell motility, from smooth muscle contraction to neurite outgrowth. The first marketed ROCK inhibitor, called fasudil, has been used safely for treatment of cerebral vasospasm since 1995 in Japan. During the succeeding decades ROCK inhibitors have been applied in many pathological conditions from central nervous system disorders to cardiovascular disease as potential therapeutic agents or experimental tools to help understand the underlying (pathomechanisms. In 2014, a fasudil derivate named ripasudil was accepted for clinical use in glaucoma and ocular hypertension. Since ROCK kinases are widely expressed in ocular tissues, they have been implicated in the pathology of many ocular conditions such as corneal dysfunction, glaucoma, cataract, diabetic retinopathy, age-related macular degeneration, and retinal detachment. This paper aims to provide an overview of the most recent status/application of ROCK inhibitors in the field of eye disease.

  14. The association study between the interaction of serotonin and norepinephrine transporter gene polymorphisms and the effects of selective serotonin reuptake inhibitors%5-羟色胺和去甲肾上腺素转运体基因多态性的交互作用与重性抑郁障碍临床疗效的关联研究

    Institute of Scientific and Technical Information of China (English)

    孟亚琴; 孙宁; 王彦芳; 段慧君; 李素萍; 彭菊意; 杜巧荣; 张克让

    2013-01-01

    Objective To explore the relevance of the interaction of serotonin and norepinephrine transporter gene polymorphisms and the effects of selective serotonin reuptake inhibitors.Methods The subjects comprised 246 patients according to the diagnostic and statistical manual of mental disorders in the fourth edition (DSM-Ⅳ) criterion for major depressive disorder(MDD).The clinical efficacy were assessed by using 17 Hamilton depression quantity (HAMD) scale after selective serotonin reuptake inhibitors(SSRIs) citalopram (20 to 60 mg/d) or paroxetine (20 to 60 mg/d) were used randomly for 1,2,4,6 weeks.Polymerase chain reaction(PCR),sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE)and DNA sequencing analysis were used to detect the genotype of 5-HTT gene single nucleotide polymorphisms (SNP) of VNTR and LPR and SNPs at rs2242446 and rs5569 of NET.SPSS13.0 software were used for statistical analysis.Results (1) An association between 5-HTT LPR and the efficacy of SSRIs was found after 6 weeks in these samples (P =0.023).The clinical efficiency of LL genotype was higher than SS + LS genotype(OR =2.225,OR 95% CI=1.118,4.427).(2) The interaction of 5-HTT LPR and NET rs5569 and the SSRIs antidepressant effects was statistical significance (P =0.01).Conclusion Preliminary study found that the interaction of 5-HTT LPR and NET rs5569 may be related to SSRIs antidepressant effects in China' s patients with MDD.%目的 探讨5-羟色胺和去甲肾上腺素转运体基因多态性的交互作用与选择性5-羟色胺再摄取抑制剂临床疗效的关联研究.方法 收集符合美国精神障碍诊断与统计手册第四版(DSM-Ⅳ)重性抑郁障碍(MDD)诊断标准的患者246例,给予选择性5-羟色胺再摄取抑制剂(SSRIs)西酞普兰(20~ 60mg/d)或帕罗西汀(20 ~ 60 mg/d),在治疗后1,2,4,6周运用17项汉密尔顿抑郁量表(HAMD)评定临床疗效;应用聚合酶链反应技术(PCR)、聚丙烯酰胺凝胶电

  15. Structural Mechanism of the Pan-BCR-ABL Inhibitor Ponatinib (AP24534): Lessons for Overcoming Kinase Inhibitor Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Tianjun; Commodore, Lois; Huang, Wei-Sheng; Wang, Yihan; Thomas, Mathew; Keats, Jeff; Xu, Qihong; Rivera, Victor M.; Shakespeare, William C.; Clackson, Tim; Dalgarno, David C.; Zhu, Xiaotian (ARIAD)

    2012-01-20

    The BCR-ABL inhibitor imatinib has revolutionized the treatment of chronic myeloid leukemia. However, drug resistance caused by kinase domain mutations has necessitated the development of new mutation-resistant inhibitors, most recently against the T315I gatekeeper residue mutation. Ponatinib (AP24534) inhibits both native and mutant BCR-ABL, including T315I, acting as a pan-BCR-ABL inhibitor. Here, we undertook a combined crystallographic and structure-activity relationship analysis on ponatinib to understand this unique profile. While the ethynyl linker is a key inhibitor functionality that interacts with the gatekeeper, virtually all other components of ponatinib play an essential role in its T315I inhibitory activity. The extensive network of optimized molecular contacts found in the DFG-out binding mode leads to high potency and renders binding less susceptible to disruption by single point mutations. The inhibitory mechanism exemplified by ponatinib may have broad relevance to designing inhibitors against other kinases with mutated gatekeeper residues.

  16. Structure-Based Design of Novel HIV-1 Protease Inhibitors to Combat Drug Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh,A.; Sridhar, P.; Leshchenko, S.; Hussain, A.; Li, J.; Kovalevsky, A.; Walters, D.; Wedelind, J.; Grum-Tokars, V.; et al.

    2006-01-01

    Structure-based design and synthesis of novel HIV protease inhibitors are described. The inhibitors are designed specifically to interact with the backbone of HIV protease active site to combat drug resistance. Inhibitor 3 has exhibited exceedingly potent enzyme inhibitory and antiviral potency. Furthermore, this inhibitor maintains impressive potency against a wide spectrum of HIV including a variety of multi-PI-resistant clinical strains. The inhibitors incorporated a stereochemically defined 5-hexahydrocyclopenta[b]furanyl urethane as the P2-ligand into the (R)-(hydroxyethylamino)sulfonamide isostere. Optically active (3aS,5R,6aR)-5-hydroxy-hexahydrocyclopenta[b]furan was prepared by an enzymatic asymmetrization of meso-diacetate with acetyl cholinesterase, radical cyclization, and Lewis acid-catalyzed anomeric reduction as the key steps. A protein-ligand X-ray crystal structure of inhibitor 3-bound HIV-1 protease (1.35 Angstroms resolution) revealed extensive interactions in the HIV protease active site including strong hydrogen bonding interactions with the backbone. This design strategy may lead to novel inhibitors that can combat drug resistance.

  17. Crystal structure of a complex of human chymase with its benzimidazole derived inhibitor

    International Nuclear Information System (INIS)

    Matsumoto, Yoshiyuki; Kakuda, Shinji; Koizumi, Masahiro; Mizuno, Tsuyoshi; Muroga, Yumiko; Kawamura, Takashi; Takimoto-Kamimura, Midori

    2013-01-01

    The crystal structure of human chymase complexed with a novel benzimidazole inhibitor, TJK002, was determined at 2.8 Å resolution. The present study shows that the benzimidazole ring of the inhibitor takes the stable stacking interaction with the protonated His57 in the catalytic domain of human chymase. The crystal structure of human chymase complexed with a novel benzimidazole inhibitor, TJK002, was determined at 2.8 Å resolution. The X-ray crystallographic study shows that the benzimidazole inhibitor forms a non-covalent interaction with the catalytic domain of human chymase. The hydrophobic fragment of the inhibitor occupies the S1 pocket. The carboxylic acid group of the inhibitor forms hydrogen bonds with the imidazole N(∊) atom of His57 and/or the O(γ) atom of Ser195 which are members of the catalytic triad. This imidazole ring of His57 induces π–π stacking to the benzene ring of the benzimidazole scaffold as P2 moiety. Fragment molecular orbital calculation of the atomic coordinates by X-ray crystallography shows that this imidazole ring of His57 could be protonated with the carboxyl group of Asp102 or hydroxyl group of Ser195 and the stacking interaction is stabilized. A new drug design strategy is proposed where the stacking to the protonated imidazole of the drug target protein with the benzimidazole scaffold inhibitor causes unpredicted potent inhibitory activity for some enzymes

  18. Endogenous Natural Complement Inhibitor Regulates Cardiac Development

    DEFF Research Database (Denmark)

    Mortensen, Simon A; Skov, Louise L; Kjaer-Sorensen, Kasper

    2017-01-01

    mechanisms during fetal development and adult homeostasis. In this article, we describe the function of an endogenous complement inhibitor, mannan-binding lectin (MBL)-associated protein (MAp)44, in regulating the composition of a serine protease-pattern recognition receptor complex, MBL-associated serine...... of MAp44 caused impaired cardiogenesis, lowered heart rate, and decreased cardiac output. These defects were associated with aberrant neural crest cell behavior. We found that MAp44 competed with MASP-3 for pattern recognition molecule interaction, and knockdown of endogenous MAp44 expression could...... be rescued by overexpression of wild-type MAp44. Our observations provide evidence that immune molecules are centrally involved in the orchestration of cardiac tissue development....

  19. 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.

  20. Binding of the Inhibitor Protein IF1 to Bovine F1-ATPase

    Science.gov (United States)

    Bason, John V.; Runswick, Michael J.; Fearnley, Ian M.; Walker, John E.

    2011-01-01

    In the structure of bovine F1-ATPase inhibited with residues 1–60 of the bovine inhibitor protein IF1, the α-helical inhibitor interacts with five of the nine subunits of F1-ATPase. In order to understand the contributions of individual amino acid residues to this complex binding mode, N-terminal deletions and point mutations have been introduced, and the binding properties of each mutant inhibitor protein have been examined. The N-terminal region of IF1 destabilizes the interaction of the inhibitor with F1-ATPase and may assist in removing the inhibitor from its binding site when F1Fo-ATPase is making ATP. Binding energy is provided by hydrophobic interactions between residues in the long α-helix of IF1 and the C-terminal domains of the βDP-subunit and βTP-subunit and a salt bridge between residue E30 in the inhibitor and residue R408 in the C-terminal domain of the βDP-subunit. Several conserved charged amino acids in the long α-helix of IF1 are also required for establishing inhibitory activity, but in the final inhibited state, they are not in contact with F1-ATPase and occupy aqueous cavities in F1-ATPase. They probably participate in the pathway from the initial interaction of the inhibitor and the enzyme to the final inhibited complex observed in the structure, in which two molecules of ATP are hydrolysed and the rotor of the enzyme turns through two 120° steps. These findings contribute to the fundamental understanding of how the inhibitor functions and to the design of new inhibitors for the systematic analysis of the catalytic cycle of the enzyme. PMID:21192948

  1. Effect of Wall Shear Stress on Corrosion Inhibitor Film Performance

    Science.gov (United States)

    Canto Maya, Christian M.

    In oil and gas production, internal corrosion of pipelines causes the highest incidence of recurring failures. Ensuring the integrity of ageing pipeline infrastructure is an increasingly important requirement. One of the most widely applied methods to reduce internal corrosion rates is the continuous injection of chemicals in very small quantities, called corrosion inhibitors. These chemical substances form thin films at the pipeline internal surface that reduce the magnitude of the cathodic and/or anodic reactions. However, the efficacy of such corrosion inhibitor films can be reduced by different factors such as multiphase flow, due to enhanced shear stress and mass transfer effects, loss of inhibitor due to adsorption on other interfaces such as solid particles, bubbles and droplets entrained by the bulk phase, and due to chemical interaction with other incompatible substances present in the stream. The first part of the present project investigated the electrochemical behavior of two organic corrosion inhibitors (a TOFA/DETA imidazolinium, and an alkylbenzyl dimethyl ammonium chloride), with and without an inorganic salt (sodium thiosulfate), and the resulting enhancement. The second part of the work explored the performance of corrosion inhibitor under multiphase (gas/liquid, solid/liquid) flow. The effect of gas/liquid multiphase flow was investigated using small and large scale apparatus. The small scale tests were conducted using a glass cell and a submersed jet impingement attachment with three different hydrodynamic patterns (water jet, CO 2 bubbles impact, and water vapor cavitation). The large scale experiments were conducted applying different flow loops (hilly terrain and standing slug systems). Measurements of weight loss, linear polarization resistance (LPR), and adsorption mass (using an electrochemical quartz crystal microbalance, EQCM) were used to quantify the effect of wall shear stress on the performance and integrity of corrosion inhibitor

  2. Synergistic interaction between two linear inhibitors on a single ...

    African Journals Online (AJOL)

    ). vanadate (Van) and L-phenylalanine (L-phe) were studied using a modification of the common Yonetani-Theorell procedure proposed for studying synergistic inhibition. The modes of inhibition of ALP by Van and L-phe as analysed using the ...

  3. Biological abatement of cellulase inhibitors.

    Science.gov (United States)

    Cao, Guangli; Ximenes, Eduardo; Nichols, Nancy N; Zhang, Leyu; Ladisch, Michael

    2013-10-01

    Removal of enzyme inhibitors released during lignocellulose pretreatment is essential for economically feasible biofuel production. We tested bio-abatement to mitigate enzyme inhibitor effects observed in corn stover liquors after pretreatment with either dilute acid or liquid hot water at 10% (w/v) solids. Bio-abatement of liquors was followed by enzymatic hydrolysis of cellulose. To distinguish between inhibitor effects on enzymes and recalcitrance of the substrate, pretreated corn stover solids were removed and replaced with 1% (w/v) Solka Floc. Cellulose conversion in the presence of bio-abated liquors from dilute acid pretreatment was 8.6% (0.1x enzyme) and 16% (1x enzyme) higher than control (non-abated) samples. In the presence of bio-abated liquor from liquid hot water pretreated corn stover, 10% (0.1x enzyme) and 13% (1x enzyme) higher cellulose conversion was obtained compared to control. Bio-abatement yielded improved enzyme hydrolysis in the same range as that obtained using a chemical (overliming) method for mitigating inhibitors. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Phosphodiesterase inhibitors in clinical urology.

    Science.gov (United States)

    Ückert, Stefan; Kuczyk, Markus A; Oelke, Matthias

    2013-05-01

    To date, benign diseases of the male and female lower urinary and genital tract, such as erectile dysfunction, bladder overactivity, lower urinary tract symptomatology secondary to benign prostatic hyperplasia and symptoms of female sexual dysfunction (including arousal and orgasmic disorders), can be therapeutically approached by influencing the function of the smooth musculature of the respective tissues. The use of isoenzyme-selective phosphodiesterase (PDE) inhibitors is considered a great opportunity to treat various diseases of the human urogenital tract. PDE inhibitors, in particular the PDE5 (cyclic GMP PDE) inhibitors avanafil, lodenafil, sildenafil, tadalafil, udenafil and vardenafil, are regarded as efficacious, having a fast onset of drug action and an improved effect-to-adverse event ratio, combining a high response rate with the advantage of an on-demand intake. The purpose of this review is to summarize recent as well as potential future indications, namely, erectile dysfunction, Peyronie's disease, overactive bladder, urinary stone disease, lower urinary tract symptomatology secondary to benign prostatic hyperplasia and premature ejaculation, for the use of PDE inhibitors in clinical urology.

  5. 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

  6. Retroviral proteinases and their inhibitors

    Czech Academy of Sciences Publication Activity Database

    Sedláček, Juraj

    2000-01-01

    Roč. 3, 3,4 (2000), s. 23-24 [ Proteolytic enzymes and their inhibitors in physiology and pathogenesis. 14.09.2000, Plzen] Institutional research plan: CEZ:AV0Z5052915 Subject RIV: EB - Genetics ; Molecular Biology

  7. Monoamine depletion by reuptake inhibitors

    Directory of Open Access Journals (Sweden)

    Hinz M

    2011-10-01

    Full Text Available Marty Hinz1, Alvin Stein2, Thomas Uncini31Clinical Research, NeuroResearch Clinics Inc, Cape Coral, FL; 2Stein Orthopedic Associates, Plantation, FL; 3DBS Labs Inc, Duluth, MN, USABackground: Disagreement exists regarding the etiology of cessation of the observed clinical results with administration of reuptake inhibitors. Traditionally, when drug effects wane, it is known as tachyphylaxis. With reuptake inhibitors, the placebo effect is significantly greater than the drug effect in the treatment of depression and attention deficit hyperactivity disorder, leading some to assert that waning of drug effects is placebo relapse, not tachyphylaxis.Methods: Two groups were retrospectively evaluated. Group 1 was composed of subjects with depression and Group 2 was composed of bariatric subjects treated with reuptake inhibitors for appetite suppression.Results: In Group 1, 200 subjects with depression were treated with citalopram 20 mg per day. A total of 46.5% (n = 93 achieved relief of symptoms (Hamilton-D rating score ≤ 7, of whom 37 (39.8% of whom experienced recurrence of depression symptoms, at which point an amino acid precursor formula was started. Within 1–5 days, 97.3% (n = 36 experienced relief of depression symptoms. In Group 2, 220 subjects were treated with phentermine 30 mg in the morning and citalopram 20 mg at 4 pm. In this group, 90.0% (n = 198 achieved adequate appetite suppression. The appetite suppression ceased in all 198 subjects within 4–48 days. Administration of an amino acid precursor formula restored appetite suppression in 98.5% (n = 195 of subjects within 1–5 days.Conclusion: Reuptake inhibitors do not increase the total number of monoamine molecules in the central nervous system. Their mechanism of action facilitates redistribution of monoamines from one place to another. In the process, conditions are induced that facilitate depletion of monoamines. The "reuptake inhibitor monoamine depletion theory" of this paper

  8. Viagra warning re "poppers" and notice re protease inhibitors.

    Science.gov (United States)

    James, J S

    1998-05-01

    Pfizer, Inc., manufacturer of Viagra (sildenafil), is warning patients that Viagra is contraindicated with nitrate inhalers (poppers). Nitrates in any form or nitric oxide donors can potentially cause hypotension. Pfizer also recommends that patients using protease inhibitors, particularly ritonavir, use a lower dose of Viagra (25 mg) because they interfere with the elimination of Viagra. This interaction does not pose a significant risk to the patient.

  9. Isotope-edited proton NMR study on the structure of a pepsin/inhibitor complex

    International Nuclear Information System (INIS)

    Fesik, S.W.; Luly, J.R.; Erickson, J.W.; Abad-Zapatero, C.

    1988-01-01

    A general approach is illustrated for providing detailed structural information on large enzyme/inhibitor complexes using NMR spectroscopy. The method involves the use of isotopically labeled ligands to simplify two-dimensional NOE spectra of large molecular complexes by isotope-editing techniques. With this approach, the backbone and side-chain conformations (at the P 2 and P 3 sites) of a tightly bound inhibitor of porcine pepsin have bene determined. In addition, structural information on the active site of pepsin has been obtained. Due to the sequence homology between porcine pepsin and human renin, this structural information may prove useful for modeling renin/inhibitor complexes with the ultimate goal of designing more effective renin inhibitors. Moreover, this general approach can be applied to study other biological systems of interest such as other enzyme/inhibitor complexes, ligands bound to soluble receptors, and enzyme/substrate interactions

  10. Crystal structures of HIV-1 nonnucleoside reverse transcriptase inhibitors: N-benzyl-4-methyl-benzimidazoles

    Science.gov (United States)

    Ziółkowska, Natasza E.; Michejda, Christopher J.; Bujacz, Grzegorz D.

    2009-07-01

    HIV-1 nonnucleoside reverse transcriptase inhibitors are potentially specific and effective drugs in AIDS therapy. The presence of two aromatic systems with an angled orientation in the molecule of the inhibitor is crucial for interactions with HIV-1 RT. The inhibitor drives like a wedge into the cluster of aromatic residues of RT HIV-1 and restrains the enzyme in a conformation that blocks the chemical step of nucleotide incorporation. Structural studies provide useful information for designing new, more active inhibitors. The crystal structures of four NNRTIs are presented here. The investigated compounds are derivatives of N-benzyl-4-methyl-benzimidazole with various aliphatic and aromatic substituents at carbon 2 positions and a 2,6-dihalogeno-substituted N-benzyl moiety. Structural data reported here show that the conformation of the investigated compounds is relatively rigid. Such feature is important for the nonnucleoside inhibitor binding to HIV-1 reverse transcriptase.

  11. Serotonin and Norepinephrine Reuptake Inhibitors (SNRIs)

    Science.gov (United States)

    Serotonin and norepinephrine reuptake inhibitors (SNRIs) Antidepressant SNRIs help relieve depression symptoms, such as irritability and sadness, ... effects they may cause. By Mayo Clinic Staff Serotonin and norepinephrine reuptake inhibitors (SNRIs) are a class ...

  12. Contemporary protease inhibitors and cardiovascular risk

    DEFF Research Database (Denmark)

    Lundgren, Jens; Mocroft, Amanda; Ryom, Lene

    2018-01-01

    PURPOSE OF REVIEW: To review the evidence linking use of HIV protease inhibitors with excess risk of cardiovascular disease (CVD) in HIV+ populations. RECENT FINDINGS: For the two contemporary most frequently used protease inhibitors, darunavir and atazanavir [both pharmacologically boosted...

  13. Role of the A+ helix in heparin binding to protein C inhibitor

    NARCIS (Netherlands)

    Elisen, M. G.; Maseland, M. H.; Church, F. C.; Bouma, B. N.; Meijers, J. C.

    1996-01-01

    Interactions between proteins and heparin(-like) structures involve electrostatic forces and structural features. Based on charge distributions in the linear sequence of protein C inhibitor (PCI), two positively charged regions of PCI were proposed as possible candidates for this interaction. The

  14. PD-1/PD-L1 Inhibitors for Immuno-oncology: From Antibodies to Small Molecules.

    Science.gov (United States)

    Geng, Qiaohong; Jiao, Peifu; Jin, Peng; Su, Gaoxing; Dong, Jinlong; Yan, Bing

    2018-02-12

    The recent regulatory approvals of immune checkpoint protein inhibitors, such as ipilimumab, pembrolizumab, nivolumab, atezolizumab, durvalumab, and avelumab ushered a new era in cancer therapy. These inhibitors do not attack tumor cells directly but instead mobilize the immune system to re-recognize and eradicate tumors, which endows them with unique advantages including durable clinical responses and substantial clinical benefits. PD-1/PD-L1 inhibitors, a pillar of immune checkpoint protein inhibitors, have demonstrated unprecedented clinical efficacy in more than 20 cancer types. Besides monoclonal antibodies, diverse PD- 1/PD-L1 inhibiting candidates, such as peptides, small molecules have formed a powerful collection of weapons to fight cancer. The goal of this review is to summarize and discuss the current PD-1/PD-L1 inhibitors including candidates under clinical development, their molecular interactions with PD-1 or PD-L1, the disclosed structureactivity relationships of peptides and small molecules as inhibitors. Current PD-1/PD-L1 inhibitors under clinical development are exclusively dominated by antibodies. The molecular interactions of therapeutic antibodies with PD-1 or PD-L1 have been gradually elucidated for the design of novel inhibitors. Various peptides and traditional small molecules have been investigated in preclinical model to discover novel PD-1/PD-L1 inhibitors. Peptides and small molecules may play an important role in immuno-oncology because they may bind to multiple immune checkpoint proteins via rational design, opening opportunity for a new generation of novel PD-1/PD-L1 inhibitors. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  15. Reduction rules for reset/inhibitor nets

    NARCIS (Netherlands)

    Verbeek, H.M.W.; Wynn, M.T.; Aalst, van der W.M.P.; Hofstede, ter A.H.M.

    2010-01-01

    Reset/inhibitor nets are Petri nets extended with reset arcs and inhibitor arcs. These extensions can be used to model cancellation and blocking. A reset arc allows a transition to remove all tokens from a certain place when the transition fires. An inhibitor arc can stop a transition from being

  16. 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...

  17. Crystal structure of a novel cysteinless plant Kunitz-type protease inhibitor

    International Nuclear Information System (INIS)

    Hansen, Daiane; Macedo-Ribeiro, Sandra; Verissimo, Paula; Yoo Im, Sonia; Sampaio, Misako Uemura; Oliva, Maria Luiza Vilela

    2007-01-01

    Bauhinia bauhinioides Cruzipain Inhibitor (BbCI) is a cysteine protease inhibitor highly homologous to plant Kunitz-type inhibitors. However, in contrast to classical Kunitz family inhibitors it lacks cysteine residues and therefore disulfide bridges. BbCI is also distinct in the ability to inactivate enzymes belonging to two different classes, cysteine and serine proteases. Besides inhibiting the cysteine protease cruzipain, BbCI also inhibits cathepsin L and the serine proteases HNE (human neutrophil elastase) and PPE (porcine pancreatic elastase). Monoclinic crystals of the recombinant inhibitor that diffract to 1.7 A resolution were obtained using hanging drop method by vapor diffusion at 18 o C. The refined structure shows the conservative β-trefoil fold features of the Kunitz inhibitors. In BbCI, one of the two characteristic S-S bonds is replaced by the water-mediated interaction between Tyr125 and Gly132. In this work we explore the structural differences between Kunitz-type inhibitors and analyze the essential interactions that maintain the protein structural stability preserving its biological function

  18. Wheat Subtilisin/Chymotrypsin Inhibitor (WSCI) as a scaffold for novel serine protease inhibitors with a given specificity.

    Science.gov (United States)

    Tedeschi, Francesca; Di Maro, Antimo; Facchiano, Angelo; Costantini, Susan; Chambery, Angela; Bruni, Natalia; Capuzzi, Valeria; Ficca, Anna Grazia; Poerio, Elia

    2012-10-30

    WSCI (Wheat Subtilisin/Chymotrypsin Inhibitor) is a small protein belonging to the Potato inhibitor I family exhibiting a high content of essential amino acid. In addition to bacterial subtilisins and mammalian chymotrypsins, WSCI inhibits chymotrypsin-like activities isolated from digestive traits of a number of insect larvae. In vivo, as suggested for many plant proteinase inhibitors, WSCI seems to play a role of natural defence against attacks of pests and pathogens. The functional region of WSCI, containing the inhibitor reactive site (Met48-Glu49), corresponds to an extended flexible loop (Val42-Asp53) whose architecture is somehow stabilized by a number of secondary interactions established with a small β-sheet located underneath. The aim of this study was to employ a WSCI molecule as a stable scaffold to obtain recombinant inhibitors with new acquired anti-proteinase activity or, alternatively, inactive WSCI variants. A gene sequence coding for the native WSCI, along with genes coding for muteins with different specficities, could be exploited to obtain transformed non-food use plants with improved insect resistance. On the other hand, the genetic transformation of cereal plants over-expressing inactive WSCI muteins could represent a possible strategy to improve the nutritional quality of cereal-based foods, without risk of interference with human or animal digestive enzymes. Here, we described the characterization of four muteins containing single/multiple amino acid substitutions at the WSCI reactive site and/or at its proximity. Modalities of interaction of these muteins with proteinases (subtilisin, trypsin and chymotrypsin) were investigated by time course hydrolysis and molecular simulations studies.

  19. 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.

  20. 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.

  1. Structural investigation of HIV-1 nonnucleoside reverse transcriptase inhibitors: 2-Aryl-substituted benzimidazoles

    Science.gov (United States)

    Ziółkowska, Natasza E.; Michejda, Christopher J.; Bujacz, Grzegorz D.

    2009-11-01

    Acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV) is one of the most destructive epidemics in history. Inhibitors of HIV enzymes are the main targets to develop drugs against that disease. Nonnucleoside reverse transcriptase inhibitors of HIV-1 (NNRTIs) are potentially effective and nontoxic. Structural studies provide information necessary to design more active compounds. The crystal structures of four NNRTI derivatives of 2-aryl-substituted N-benzyl-benzimidazole are presented here. Analysis of the geometrical parameters shows that the structures of the investigated inhibitors are rigid. The important geometrical parameter is the dihedral angle between the planes of the π-electron systems of the benzymidazole and benzyl moieties. The values of these dihedral angles are in a narrow range for all investigated inhibitors. There is no significant difference between the structure of the free inhibitor and the inhibitor in the complex with RT HIV-1. X-ray structures of the investigated inhibitors are a good basis for modeling enzyme-inhibitor interactions in rational drug design.

  2. Structure of a retro-binding peptide inhibitor complexed with human alpha-thrombin.

    Science.gov (United States)

    Tabernero, L; Chang, C Y; Ohringer, S L; Lau, W F; Iwanowicz, E J; Han, W C; Wang, T C; Seiler, S M; Roberts, D G; Sack, J S

    1995-02-10

    The crystallographic structure of the ternary complex between human alpha-thrombin, hirugen and the peptidyl inhibitor Phe-alloThr-Phe-O-CH3, which is acylated at its N terminus with 4-guanidino butanoic acid (BMS-183507), has been determined at 2.6 A resolution. The structure reveals a unique "retro-binding" mode for this tripeptide active site inhibitor. The inhibitor binds with its alkyl-guanidine moiety in the primary specificity pocket and its two phenyl rings occupying the hydrophobic proximal and distal pockets of the thrombin active site. In this arrangement the backbone of the tripeptide forms a parallel beta-strand to the thrombin main-chain at the binding site. This is opposite to the orientation of the natural substrate, fibrinogen, and all the small active site-directed thrombin inhibitors whose bound structures have been previously reported. BMS-183507 is the first synthetic inhibitor proved to bind in a retro-binding fashion to thrombin, in a fashion similar to that of the N-terminal residues of the natural inhibitor hirudin. Furthermore, this new potent thrombin inhibitor (Ki = 17.2 nM) is selective for thrombin over other serine proteases tested and may be a template to be considered in designing hirudin-based thrombin inhibitors with interactions at the specificity pocket.

  3. Stabilization versus inhibition of TAFIa by competitive inhibitors in vitro

    NARCIS (Netherlands)

    Walker, J.B.; Hughes, B.; James, I.; Haddock, P.; Kluft, C.; Bajzar, L.

    2003-01-01

    Two competitive inhibitors of TAFIa (activated thrombin-activable fibrinolysis inhibitor), 2-guanidinoethyl-mercaptosuccinic acid and potato tuber carboxypeptidase inhibitor, variably affect fibrinolysis of clotted human plasma. Depending on their concentration, the inhibitors shortened, prolonged,

  4. 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.

  5. Structures of human Golgi-resident glutaminyl cyclase and its complexes with inhibitors reveal a large loop movement upon inhibitor binding.

    Science.gov (United States)

    Huang, Kai-Fa; Liaw, Su-Sen; Huang, Wei-Lin; Chia, Cho-Yun; Lo, Yan-Chung; Chen, Yi-Ling; Wang, Andrew H-J

    2011-04-08

    Aberrant pyroglutamate formation at the N terminus of certain peptides and proteins, catalyzed by glutaminyl cyclases (QCs), is linked to some pathological conditions, such as Alzheimer disease. Recently, a glutaminyl cyclase (QC) inhibitor, PBD150, was shown to be able to reduce the deposition of pyroglutamate-modified amyloid-β peptides in brain of transgenic mouse models of Alzheimer disease, leading to a significant improvement of learning and memory in those transgenic animals. Here, we report the 1.05-1.40 Å resolution structures, solved by the sulfur single-wavelength anomalous dispersion phasing method, of the Golgi-luminal catalytic domain of the recently identified Golgi-resident QC (gQC) and its complex with PBD150. We also describe the high-resolution structures of secretory QC (sQC)-PBD150 complex and two other gQC-inhibitor complexes. gQC structure has a scaffold similar to that of sQC but with a relatively wider and negatively charged active site, suggesting a distinct substrate specificity from sQC. Upon binding to PBD150, a large loop movement in gQC allows the inhibitor to be tightly held in its active site primarily by hydrophobic interactions. Further comparisons of the inhibitor-bound structures revealed distinct interactions of the inhibitors with gQC and sQC, which are consistent with the results from our inhibitor assays reported here. Because gQC and sQC may play different biological roles in vivo, the different inhibitor binding modes allow the design of specific inhibitors toward gQC and sQC.

  6. Inhibition of xyloglucanase from an alkalothermophilic Thermomonospora sp. by a peptidic aspartic protease inhibitor from Penicillium sp. VM24.

    Science.gov (United States)

    Menon, Vishnu; Rao, Mala

    2012-11-01

    A bifunctional inhibitor from Penicillium sp VM24 causing inactivation of xyloglucanase from Thermomonospora sp and an aspartic protease from Aspergillus saitoi was identified. Steady state kinetics studies of xyloglucanase and the inhibitor revealed an irreversible, non-competitive, two-step inhibition mechanism with IC(50) and K(i) values of 780 and 500nM respectively. The interaction of o-phthalaldehyde (OPTA)-labeled xyloglucanase with the inhibitor revealed that the inhibitor binds to the active site of the enzyme. Far- and near-UV spectrophotometric analysis suggests that the conformational changes induced in xyloglucanase by the inhibitor may be due to irreversible denaturation of enzyme. The bifunctional inhibitor may have potential as a biocontrol agent for the protection of plants against phytopathogenic fungi. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Angiotensin converting enzyme inhibitors and Alzheimer disease in the presence of the apolipoprotein E4 allele.

    Science.gov (United States)

    Qiu, Wendy Wei Qiao; Lai, Angela; Mon, Timothy; Mwamburi, Mkaya; Taylor, Warren; Rosenzweig, James; Kowall, Neil; Stern, Robert; Zhu, Haihao; Steffens, David C

    2014-02-01

    The effect of angiotensin converting enzyme (ACE) inhibitors on Alzheimer disease (AD) remains unclear, with conflicting results reported. We studied the interaction of the Apolipoprotein E (ApoE) genotype and ACE inhibitors on AD. This was a cross-sectional study of homebound elderly with an AD diagnosis and documentation of medications taken. ApoE genotype was determined. A total of 355 subjects with status on ApoE alleles and cognitive diagnoses were studied. The average age (mean ± SD) of this population was 73.3 ± 8.3 years old, and 73% were female. Cross-sectionally, there was no difference in the number of AD cases between ApoE4 carriers and ApoE4 non-carriers or between ACE inhibitor users and non-users in the homebound elderly. ApoE4 carriers treated with ACE inhibitors, however, had more diagnoses of AD compared with those who did not have the treatment (28% versus 6%, p = 0.01) or ApoE4 non-carriers treated with an ACE inhibitor (28% versus 10%, p = 0.03). ACE inhibitor use was associated with AD diagnosis only in the presence of an E4 allele. Using multivariate logistic regression analysis, we found that in diagnosed AD cases there was a significant interaction between ApoE4 and ACE inhibitor use (odds ratio: 20.85; 95% confidence interval: 3.08-140.95; p = 0.002) after adjusting for age, sex, ethnicity, and education. The effects of ACE inhibitors on AD may be different depending on ApoE genotype. A prospective study is needed to determine whether ACE inhibitor use accelerates or poorly delays AD development in ApoE4 carriers compared with ApoE4 non-carriers. Copyright © 2014. Published by Elsevier Inc.

  8. Structural insights into the binding mechanism of IDO1 with hydroxylamidine based inhibitor INCB14943

    International Nuclear Information System (INIS)

    Wu, You; Xu, Tingting; Liu, Jinsong; Ding, Ke; Xu, Jinxin

    2017-01-01

    IDO1 (indoleamine 2, 3-dioxygenase 1), a well characterized immunosuppressive enzyme, has attracted growing attention as a potential target for cancer immunotherapy. Hydroxylamidine compounds INCB024360 and INCB14943 (INCB024360 analogue) are highly effective IDO1 inhibitors. INCB024360 is undergoing clinical trials for treatment of various types of human cancer. Here, we determined the co-crystal structure of IDO1 and INCB14943, and elucidate the detailed binding mode. INCB14943 binds to heme iron in IDO1 protein through the oxime nitrogen. Further analysis also reveals that a halogen bonding interaction between the chlorine atom (3-Cl) of INCB14943 and the sulphur atom of C129 significantly improves the inhibition activity against IDO1. Comparing with the other reported inhibitors, the oxime nitrogen and halogen bond interaction are identified as the unique features of INCB14943 among the IDO1 inhibitors. Thus, our study provides novel insights into the interaction between a small molecule inhibitor INCB14943 and IDO1 protein. The structural information will facilitate future IDO1 inhibitor design. - Highlights: • This is the first co-crystal structure of IDO1 with hydroxylamidine compound. • INCB14943 binds to heme iron through oxime nitrogen instead of imidazole nitrogen. • Halogen bond interaction with C129 is another unique feature of INCB14943.

  9. 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

  10. Calcineurin-inhibitor pain syndrome.

    Science.gov (United States)

    Prommer, Eric

    2012-07-01

    There has been increased recognition of calcineurin, a phosphoprotein serine/threonine phosphatase enzyme, in the regulation of many physiologic systems. Calcineurin mediates activation of lymphocytes, which play a role in immune response. Widely distributed in the central nervous system, calcinuerin also plays an important role in sensory neural function, via its role in the regulation of newly discovered 2-pore potassium channels, which greatly influence neuronal resting membrane potentials. Calcinuerin inhibition is the mechanism of action of immunomodulatory drugs such as cyclosporine and tacrolimus, which are widely used in transplantation medicine to prevent rejection. While important for immunosuppression, the use of calcineurin inhibitors has been associated with the development of a new pain syndrome called the calcineurin pain syndrome, which appears to be an untoward complication of the interruption of the physiologic function of calcineurin. This is a narrative review focusing on the epidemiology, pathophysiology, characterization of a newly recognized pain syndrome associated with the use of calcineurin inhibitors. The use of immunosuppressants however is associated with several well-known toxicities to which the calcineurin pain syndrome can be added. The development of this syndrome most likely involves altered nociceptive processing due to the effect of calcineurin inhibition on neuronal firing, as well as effects of calcineurin on vascular tone. The most striking aspect of the treatment of this syndrome is the response to calcium channel blockers, which suggest that the effects of calcineurin inhibition on vascular tone play an important role in the development of the calcineurin pain syndrome. The calcineurin syndrome is a newly recognized complication associated with the use of calcineurin inhibitors. There is no standard therapy at this time but anecdotal reports suggest the effectiveness of calcium channel blockers.

  11. Interdependence of Inhibitor Recognition in HIV-1 Protease.

    Science.gov (United States)

    Paulsen, Janet L; Leidner, Florian; Ragland, Debra A; Kurt Yilmaz, Nese; Schiffer, Celia A

    2017-05-09

    Molecular recognition is a highly interdependent process. Subsite couplings within the active site of proteases are most often revealed through conditional amino acid preferences in substrate recognition. However, the potential effect of these couplings on inhibition and thus inhibitor design is largely unexplored. The present study examines the interdependency of subsites in HIV-1 protease using a focused library of protease inhibitors, to aid in future inhibitor design. Previously a series of darunavir (DRV) analogs was designed to systematically probe the S1' and S2' subsites. Co-crystal structures of these analogs with HIV-1 protease provide the ideal opportunity to probe subsite interdependency. All-atom molecular dynamics simulations starting from these structures were performed and systematically analyzed in terms of atomic fluctuations, intermolecular interactions, and water structure. These analyses reveal that the S1' subsite highly influences other subsites: the extension of the hydrophobic P1' moiety results in 1) reduced van der Waals contacts in the P2' subsite, 2) more variability in the hydrogen bond frequencies with catalytic residues and the flap water, and 3) changes in the occupancy of conserved water sites both proximal and distal to the active site. In addition, one of the monomers in this homodimeric enzyme has atomic fluctuations more highly correlated with DRV than the other monomer. These relationships intricately link the HIV-1 protease subsites and are critical to understanding molecular recognition and inhibitor binding. More broadly, the interdependency of subsite recognition within an active site requires consideration in the selection of chemical moieties in drug design; this strategy is in contrast to what is traditionally done with independent optimization of chemical moieties of an inhibitor.

  12. Strategic Design of an Effective beta-Lactamase Inhibitor

    Energy Technology Data Exchange (ETDEWEB)

    Pattanaik, P.; Bethel, C; Hujer, A; Hujer, K; Distler, A; Taracila, M; Anderson, V; Fritsche, T; Jones, R; et. al.

    2009-01-01

    In an effort to devise strategies for overcoming bacterial beta-lactamases, we studied LN-1-255, a 6-alkylidene-2'-substituted penicillin sulfone inhibitor. By possessing a catecholic functionality that resembles a natural bacterial siderophore, LN-1-255 is unique among beta-lactamase inhibitors. LN-1-255 combined with piperacillin was more potent against Escherichia coli DH10B strains bearing bla(SHV) extended-spectrum and inhibitor-resistant beta-lactamases than an equivalent amount of tazobactam and piperacillin. In addition, LN-1-255 significantly enhanced the activity of ceftazidime and cefpirome against extended-spectrum cephalosporin and Sme-1 containing carbapenem-resistant clinical strains. LN-1-255 inhibited SHV-1 and SHV-2 beta-lactamases with nm affinity (K(I) = 110 +/- 10 and 100 +/- 10 nm, respectively). When LN-1-255 inactivated SHV beta-lactamases, a single intermediate was detected by mass spectrometry. The crystal structure of LN-1-255 in complex with SHV-1 was determined at 1.55A resolution. Interestingly, this novel inhibitor forms a bicyclic aromatic intermediate with its carbonyl oxygen pointing out of the oxyanion hole and forming hydrogen bonds with Lys-234 and Ser-130 in the active site. Electron density for the 'tail' of LN-1-255 is less ordered and modeled in two conformations. Both conformations have the LN-1-255 carboxyl group interacting with Arg-244, yet the remaining tails of the two conformations diverge. The observed presence of the bicyclic aromatic intermediate with its carbonyl oxygen positioned outside of the oxyanion hole provides a rationale for the stability of this inhibitory intermediate. The 2'-substituted penicillin sulfone, LN-1-255, is proving to be an important lead compound for novel beta-lactamase inhibitor design.

  13. Rational redesign of inhibitors of furin/kexin processing proteases by electrostatic mutations.

    Science.gov (United States)

    Cai, Xiao-hui; Zhang, Qing; Ding, Da-fu

    2004-12-01

    To model the three-dimensional structure and investigate the interaction mechanism of the proprotein convertase furin/kexin and their inhibitors (eglin c mutants). The three-dimensional complex structures of furin/kexin with its inhibitors, eglin c mutants, were generated by modeller program using the newly published X-ray crystallographical structures of mouse furin and yeast kexin as templates. The electrostatic interaction energy of each complex was calculated and the results were compared with the experimentally determined inhibition constants to find the correlation between them. High quality models of furin/kexin-eglin c mutants were obtained and used for calculation of the electrostatic interaction energies between the proteases and their inhibitors. The calculated electrostatic energies of interaction showed a linear correlation to the experimental inhibition constants. The modeled structures give good explanations of the specificity of eglin c mutants to furin/kexin. The electrostatic interactions play important roles in inhibitory activity of eglin c mutants to furin/kexin. The results presented here provided quantitative structural and functional information concerning the role of the charge-charge interactions in the binding of furin/kexin and their inhibitors.

  14. Soilless plant growth media influence the efficacy of phytohormones and phytohormone inhibitors.

    Science.gov (United States)

    Best, Norman B; Hartwig, Thomas; Budka, Joshua S; Bishop, Brandon J; Brown, Elliot; Potluri, Devi P V; Cooper, Bruce R; Premachandra, Gnanasiri S; Johnston, Cliff T; Schulz, Burkhard

    2014-01-01

    Plant growth regulators, such as hormones and their respective biosynthesis inhibitors, are effective tools to elucidate the physiological function of phytohormones in plants. A problem of chemical treatments, however, is the potential for interaction of the active compound with the growth media substrate. We studied the interaction and efficacy of propiconazole, a potent and specific inhibitor of brassinosteroid biosynthesis, with common soilless greenhouse growth media for rice, sorghum, and maize. Many of the tested growth media interacted with propiconazole reducing its efficacy up to a hundred fold. To determine the molecular interaction of inhibitors with media substrates, Fourier Transform Infrared Spectroscopy and sorption isotherm analysis was applied. While mica clay substrates absorbed up to 1.3 mg of propiconazole per g substrate, calcined clays bound up to 12 mg of propiconazole per g substrate. The efficacy of the gibberellic acid biosynthesis inhibitor, uniconazole, and the most active brassinosteroid, brassinolide, was impacted similarly by the respective substrates. Conversely, gibberellic acid showed no distinct growth response in different media. Our results suggest that the reduction in efficacy of propiconazole, uniconazole, and brassinolide in bioassays when grown in calcined clay is caused by hydrophobic interactions between the plant growth regulators and the growth media. This was further confirmed by experiments using methanol-water solvent mixes with higher hydrophobicity values, which reduce the interaction of propiconazole and calcined clay.

  15. Aurintricarboxylic acid is a potent inhibitor of phosphofructokinase.

    Science.gov (United States)

    McCune, S A; Foe, L G; Kemp, R G; Jurin, R R

    1989-01-01

    Aurintricarboxylic acid (ATA) was found to be a very potent inhibitor of purified rabbit liver phosphofructokinase (PFK), giving 50% inhibition at 0.2 microM. The inhibition was in a manner consistent with interaction at the citrate-inhibitory site of the enzyme. The data suggest that inhibition of PFK by ATA was not due to denaturation of the enzyme or the irreversible binding of inhibitor, since the inhibition could be reversed by addition of allosteric activators of PFK, i.e. fructose 2,6-bisphosphate or AMP. Two other tricarboxylic acids, agaric acid and (-)-hydroxycitrate, were found to inhibit PFK. ATA at much higher concentrations (500 microM) was shown to inhibit fatty acid synthesis from endogenous glycogen in rat hepatocytes; however, protein synthesis was not altered. PMID:2525029

  16. 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.

  17. Crystallization inhibitors for amorphous oxides

    International Nuclear Information System (INIS)

    Reznitskij, L.A.; Filippova, S.E.

    1993-01-01

    Data for the last 10 years, in which experimental results of studying the temperature stabilization of x-ray amorphous oxides (including R 3 Fe 5 O 12 R-rare earths, ZrO 2 , In 2 O 3 , Sc 2 O 3 ) and their solid solution are presented, are generalized. Processes of amorphous oxide crystallization with the production of simple oxides, solid solutions and chemical compounds with different polyhedral structure, are investigated. Energy and crystallochemical criteria for selecting the doping inhibitor-components stabilizing the amorphous state are ascertained, temperatures and enthalpies of amorpous oxide crystallization are determined, examination of certain provisions of iso,orphous miscibility theory is conducted

  18. Inhibitors of plant hormone transport

    Czech Academy of Sciences Publication Activity Database

    Klíma, Petr; Laňková, Martina; Zažímalová, Eva

    2016-01-01

    Roč. 253, č. 6 (2016), s. 1391-1404 ISSN 0033-183X R&D Projects: GA MŠk(CZ) LD15088 Institutional support: RVO:61389030 Keywords : polar auxin transport * acid-binding protein * gnom arf-gef * equilibrative nucleoside transporter * efflux carrier polarity * plasma-membrane-protein * cultured tobacco cells * arabidopsis-thaliana * gravitropic response * brefeldin-a * Plant hormones * Transport * Inhibitors * Auxin * Cytokinins * Strigolactones * Abscisic acid * Cell biology Subject RIV: ED - Physiology Impact factor: 2.870, year: 2016

  19. Effect of the Flexible Regions of the Oncoprotein Mouse Double Minute X on Inhibitor Binding Affinity.

    Science.gov (United States)

    Qin, Lingyun; Liu, Huili; Chen, Rong; Zhou, Jingjing; Cheng, Xiyao; Chen, Yao; Huang, Yongqi; Su, Zhengding

    2017-11-07

    The oncoprotein MdmX (mouse double minute X) is highly homologous to Mdm2 (mouse double minute 2) in terms of their amino acid sequences and three-dimensional conformations, but Mdm2 inhibitors exhibit very weak affinity for MdmX, providing an excellent model for exploring how protein conformation distinguishes and alters inhibitor binding. The intrinsic conformation flexibility of proteins plays pivotal roles in determining and predicting the binding properties and the design of inhibitors. Although the molecular dynamics simulation approach enables us to understand protein-ligand interactions, the mechanism underlying how a flexible binding pocket adapts an inhibitor has been less explored experimentally. In this work, we have investigated how the intrinsic flexible regions of the N-terminal domain of MdmX (N-MdmX) affect the affinity of the Mdm2 inhibitor nutlin-3a using protein engineering. Guided by heteronuclear nuclear Overhauser effect measurements, we identified the flexible regions that affect inhibitor binding affinity around the ligand-binding pocket on N-MdmX. A disulfide engineering mutant, N-MdmX C25-C110/C76-C88 , which incorporated two staples to rigidify the ligand-binding pocket, allowed an affinity for nutlin-3a higher than that of wild-type N-MdmX (K d ∼ 0.48 vs K d ∼ 20.3 μM). Therefore, this mutant provides not only an effective protein model for screening and designing of MdmX inhibitors but also a valuable clue for enhancing the intermolecular interactions of the pharmacophores of a ligand with pronounced flexible regions. In addition, our results revealed an allosteric ligand-binding mechanism of N-MdmX in which the ligand initially interacts with a compact core, followed by augmenting intermolecular interactions with intrinsic flexible regions. This strategy should also be applicable to many other protein targets to accelerate drug discovery.

  20. Laura: Soybean variety lacking Kunitz trypsin inhibitor

    Directory of Open Access Journals (Sweden)

    Srebrić Mirjana

    2010-01-01

    Full Text Available Grain of conventional soybean varieties requires heat processing to break down trypsin inhibitor's activity before using as food or animal feed. At the same time, protein denaturation and other qualitative changes occur in soybean grain, especially if the temperature of heating is not controlled. Two types of trypsin inhibitor were found in soybean grain the Kunitz trypsin inhibitor and the Bowman-Birk inhibitor. Mature grain of soybean Laura is lacking Kunitz trypsin inhibitor. Grain yield of variety Laura is equal to high yielding varieties from the maturity group I, where it belongs. Lacking of Kunitz-trypsin inhibitor makes soybean grain suitable for direct feeding in adult non ruminant animals without previous thermal processing. Grain of variety Laura can be processed for a shorter period of time than conventional soybeans. This way we save energy, and preserve valuable nutritional composition of soybean grain, which is of interest in industrial processing.

  1. Synergistic efficacy in human ovarian cancer cells by histone deacetylase inhibitor TSA and proteasome inhibitor PS-341.

    Science.gov (United States)

    Fang, Yong; Hu, Yi; Wu, Peng; Wang, Beibei; Tian, Yuan; Xia, Xi; Zhang, Qinghua; Chen, Tong; Jiang, Xuefeng; Ma, Quanfu; Xu, Gang; Wang, Shixuan; Zhou, Jianfeng; Ma, Ding; Meng, Li

    2011-05-01

    Histone deacetylase inhibitors and proteasome inhibitor are all emerging as new classes of anticancer agents. We chose TSA and PS-341 to identify whether they have a synergistic efficacy on human ovarian cancer cells. After incubated with 500 nM TSA or/and 40 nM PS-341, we found that combined groups resulted in a striking increase of apoptosis and G2/M blocking rates, no matter in A2780, cisplatin-sensitive ovarian cancer cell line OV2008 or its resistant variant C13*. This demonstrated that TSA interacted synergistically with PS-341, which raised the possibility that combined the two drugs may represent a novel strategy in ovarian cancer.

  2. 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.

  3. Proton pump inhibitors and osteoporosis

    DEFF Research Database (Denmark)

    Andersen, Bjarne Nesgaard; Johansen, Per Birger; Abrahamsen, Bo

    2016-01-01

    PURPOSE OF REVIEW: The purpose of the review is to provide an update on recent advances in the evidence based on proton pump inhibitors (PPI) as a possible cause of osteoporosis and osteoporotic fractures. This review focuses, in particular, on new studies published in the last 18 months and a di......PURPOSE OF REVIEW: The purpose of the review is to provide an update on recent advances in the evidence based on proton pump inhibitors (PPI) as a possible cause of osteoporosis and osteoporotic fractures. This review focuses, in particular, on new studies published in the last 18 months...... and a discussion of these findings and how this has influenced our understanding of this association, the clinical impact and the underlying pathophysiology. RECENT FINDINGS: New studies have further strengthened existing evidence linking use of PPIs to osteoporosis. Short-term use does not appear to pose a lower...... risk than long-term use. There is a continued lack of conclusive studies identifying the pathogenesis. Direct effects on calcium absorption or on osteoblast or osteoclast action cannot at present plausibly explain the mechanism. SUMMARY: The use of PPIs is a risk factor for development of osteoporosis...

  4. 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.

  5. Covalent docking of selected boron-based serine beta-lactamase inhibitors

    Science.gov (United States)

    Sgrignani, Jacopo; Novati, Beatrice; Colombo, Giorgio; Grazioso, Giovanni

    2015-05-01

    AmpC β-lactamase is a hydrolytic enzyme conferring resistance to β-lactam antibiotics in multiple Gram-negative bacteria. Therefore, identification of non-β-lactam compounds able to inhibit the enzyme is crucial for the development of novel antibacterial therapies. In general, AmpC inhibitors have to engage the highly solvent-exposed catalytic site of the enzyme. Therefore, understanding the implications of ligand-protein induced-fit and water-mediated interactions behind the inhibitor-enzyme recognition process is fundamental for undertaking structure-based drug design process. Here, we focus on boronic acids, a promising class of beta-lactamase covalent inhibitors. First, we optimized a docking protocol able to reproduce the experimentally determined binding mode of AmpC inhibitors bearing a boronic group. This goal was pursued (1) performing rigid and flexible docking calculations aiming to establish the role of the side chain conformations; and (2) investigating the role of specific water molecules in shaping the enzyme active site and mediating ligand protein interactions. Our calculations showed that some water molecules, conserved in the majority of the considered X-ray structures, are needed to correctly predict the binding pose of known covalent AmpC inhibitors. On this basis, we formalized our findings in a docking and scoring protocol that could be useful for the structure-based design of new boronic acid AmpC inhibitors.

  6. PTP1B inhibitor promotes endothelial cell motility by activating the DOCK180/Rac1 pathway.

    Science.gov (United States)

    Wang, Yuan; Yan, Feng; Ye, Qing; Wu, Xiao; Jiang, Fan

    2016-04-07

    Promoting endothelial cell (EC) migration is important not only for therapeutic angiogenesis, but also for accelerating re-endothelialization after vessel injury. Several recent studies have shown that inhibition of protein tyrosine phosphatase 1B (PTP1B) may promote EC migration and angiogenesis by enhancing the vascular endothelial growth factor receptor-2 (VEGFR2) signalling. In the present study, we demonstrated that PTP1B inhibitor could promote EC adhesion, spreading and migration, which were abolished by the inhibitor of Rac1 but not RhoA GTPase. PTP1B inhibitor significantly increased phosphorylation of p130Cas, and the interactions among p130Cas, Crk and DOCK180; whereas the phosphorylation levels of focal adhesion kinase, Src, paxillin, or Vav2 were unchanged. Gene silencing of DOCK180, but not Vav2, abrogated the effects of PTP1B inhibitor on EC motility. The effects of PTP1B inhibitor on EC motility and p130Cas/DOCK180 activation persisted in the presence of the VEGFR2 antagonist. In conclusion, we suggest that stimulation of the DOCK180 pathway represents an alternative mechanism of PTP1B inhibitor-stimulated EC motility, which does not require concomitant VEGFR2 activation as a prerequisite. Therefore, PTP1B inhibitor may be a useful therapeutic strategy for promoting EC migration in cardiovascular patients in which the VEGF/VEGFR functions are compromised.

  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. Potent and Selective Peptidyl Boronic Acid Inhibitors of the Serine Protease Prostate-Specific Antigen

    Science.gov (United States)

    LeBeau, Aaron M.; Singh, Pratap; Isaacs, John T.; Denmeade, Samuel R.

    2012-01-01

    SUMMARY Prostate cancer cells produce high (microgram to milligram/milliliter) levels of the serine protease Prostate-Specific Antigen (PSA). PSA is enzymatically active in the extracellular fluid surrounding prostate cancers but is found at 1,000- to 10,000-fold lower concentrations in the circulation, where it is inactivated due to binding to abundant serum protease inhibitors. The exclusive presence of high levels of active PSA within prostate cancer sites makes PSA an attractive candidate for targeted imaging and therapeutics. A synthetic approach based on a peptide substrate identified first peptide aldehyde and then boronic acid inhibitors of PSA. The best of these had the sequence Cbz-Ser-Ser-Lys-Leu-(boro)Leu, with a Ki for PSA of 65 nM. The inhibitor had a 60-fold higher Ki for chymotrypsin. A validated model of PSA’s catalytic site confirmed the critical interactions between the inhibitor and residues within the PSA enzyme. PMID:18635003

  9. Discovery of novel SERCA inhibitors by virtual screening of a large compound library.

    Science.gov (United States)

    Elam, Christopher; Lape, Michael; Deye, Joel; Zultowsky, Jodie; Stanton, David T; Paula, Stefan

    2011-05-01

    Two screening protocols based on recursive partitioning and computational ligand docking methodologies, respectively, were employed for virtual screens of a compound library with 345,000 entries for novel inhibitors of the enzyme sarco/endoplasmic reticulum calcium ATPase (SERCA), a potential target for cancer chemotherapy. A total of 72 compounds that were predicted to be potential inhibitors of SERCA were tested in bioassays and 17 displayed inhibitory potencies at concentrations below 100 μM. The majority of these inhibitors were composed of two phenyl rings tethered to each other by a short link of one to three atoms. Putative interactions between SERCA and the inhibitors were identified by inspection of docking-predicted poses and some of the structural features required for effective SERCA inhibition were determined by analysis of the classification pattern employed by the recursive partitioning models. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  10. Benzaldehyde, 2-hydroxybenzoyl hydrazone derivatives as inhibitors of the corrosion of aluminium in hydrochloric acid.

    Science.gov (United States)

    Fouda, A S; Gouda, M M; El-Rahman, S I

    2000-05-01

    The effect of benzaldehyde, 2-hydroxybenzoyl hydrazone derivatives on the corrosion of aluminium in hydrochloric acid has been investigated using thermometric and polarization techniques. The inhibitive efficiency ranking of these compounds from both techniques was found to be: 2>3>1>4. The inhibitors acted as mixed-type inhibitors but the cathode is more polarized. The relative inhibitive efficiency of these compounds has been explained on the basis of structure of the inhibitors and their mode of interaction at the surface. Results show that these additives are adsorbed on an aluminium surface according to the Langmuir isotherm. Polarization measurements indicated that the rate of corrosion of aluminium rapidly increases with temperature over the range 30-55 degrees C both in the absence and in the presence of inhibitors. Some thermodynamic data of the adsorption process are calculated and discussed.

  11. Oral direct thrombin inhibitors or oral factor Xa inhibitors for the treatment of deep vein thrombosis.

    Science.gov (United States)

    Robertson, Lindsay; Kesteven, Patrick; McCaslin, James E

    2015-06-30

    Deep vein thrombosis (DVT) is a condition in which a clot forms in the deep veins, most commonly of the leg. It occurs in approximately 1 in 1,000 people. If left untreated, the clot can travel up to the lungs and cause a potentially life-threatening pulmonary embolism (PE). Previously, a DVT was treated with the anticoagulants heparin and vitamin K antagonists. However, two forms of novel oral anticoagulants (NOACs) have been developed: oral direct thrombin inhibitors (DTI) and oral factor Xa inhibitors. The new drugs have characteristics that may be favourable over conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or re-dosing and few known drug interactions. To date, no Cochrane review has measured the effectiveness and safety of these drugs in the treatment of DVT. To assess the effectiveness of oral DTIs and oral factor Xa inhibitors for the treatment of DVT. The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched January 2015) and the Cochrane Register of Studies (last searched January 2015). We searched clinical trials databases for details of ongoing or unpublished studies and the reference lists of relevant articles retrieved by electronic searches for additional citations. We included randomised controlled trials in which people with a DVT confirmed by standard imaging techniques, were allocated to receive an oral DTI or an oral factor Xa inhibitor for the treatment of DVT. Two review authors (LR, JM) independently extracted the data and assessed the risk of bias in the trials. Any disagreements were resolved by discussion with the third review author (PK). We performed meta-analyses when we considered heterogeneity low. The two primary outcomes were recurrent VTE and PE. Other outcomes included all-cause mortality and major bleeding. We calculated all outcomes using an odds ratio (OR) with a 95% confidence interval (CI). We included

  12. Computational revelation of binding mechanisms of inhibitors to endocellular protein tyrosine phosphatase 1B using molecular dynamics simulations.

    Science.gov (United States)

    Yan, Fangfang; Liu, Xinguo; Zhang, Shaolong; Su, Jing; Zhang, Qinggang; Chen, Jianzhong

    2017-11-06

    Endocellular protein tyrosine phosphatase 1B (PTP1B) is one of the most promising target for designing and developing drugs to cure type-II diabetes and obesity. Molecular dynamics (MD) simulations combined with molecular mechanics generalized Born surface area (MM-GBSA) and solvated interaction energy methods were applied to study binding differences of three inhibitors (ID: 901, 941, and 968) to PTP1B, the calculated results show that the inhibitor 901 has the strongest binding ability to PTP1B among the current inhibitors. Principal component (PC) analysis was also carried out to investigate the conformational change of PTP1B, and the results indicate that the associations of inhibitors with PTP1B generate a significant effect on the motion of the WPD-loop. Free energy decomposition method was applied to study the contributions of individual residues to inhibitor bindings, it is found that three inhibitors can generate hydrogen bonding interactions and hydrophobic interactions with different residues of PTP1B, which provide important forces for associations of inhibitors with PTP1B. This research is expected to give a meaningfully theoretical guidance to design and develop of effective drugs curing type-II diabetes and obesity.

  13. Cell penetrating peptides to dissect host-pathogen protein-protein interactions in Theileria -transformed leukocytes

    KAUST Repository

    Haidar, Malak; de Laté , Perle Latré ; Kennedy, Eileen J.; Langsley, Gordon

    2017-01-01

    One powerful application of cell penetrating peptides is the delivery into cells of molecules that function as specific competitors or inhibitors of protein-protein interactions. Ablating defined protein-protein interactions is a refined way

  14. TYROSINE KINASE INHIBITORS AND PREGNANCY

    Directory of Open Access Journals (Sweden)

    Elisabetta Abruzzese

    2014-04-01

    Full Text Available The management of patients with chronic myeloid leukemia (CML during pregnancy has became recently a matter of continuous debate.  The introduction of the Tyrosine Kinase Inhibitors (TKIs in clinical practice has dramatically changed the prognosis of CML patients.  Patients diagnosed in chronic phase can reasonably expect many years of excellent disease control and good quality of life, as well as a normal life expectancy.  This fact has come the necessity to address issues relating to fertility and pregnancy. Physicians are not infrequently being asked for advice regarding the need for, and or the appropriateness of, stopping treatment in order to conceive. In this report we will review the data published in terms of fertility, conception, pregnancy, pregnancy outcome and illness control for all the approved TKIs, as well as suggest how to manage a planned and/or unplanned pregnancy.

  15. PARP Inhibitors in Ovarian Cancer.

    Science.gov (United States)

    Mittica, Gloria; Ghisoni, Eleonora; Giannone, Gaia; Genta, Sofia; Aglietta, Massimo; Sapino, Anna; Valabrega, Giorgio

    2018-03-05

    Treatment of Epithelial Ovarian Cancer (EOC), historically based on surgery and platinum doublet chemotherapy, is associated with high risk of relapse and poor prognosis for recurrent disease. In this landscape, the innovative treatment with PARP inhibitors (PARPis) demonstrated an outstanding activity in EOC, and is currently changing clinical practice in BRCA mutant patients. To highlight the mechanism of action, pharmacokinetics, clinical activity, indications and current strategies of development of Olaparib, Niraparib, Rucaparib, Talazoparib and Veliparib, the 5 most relevant PARPis. We performed a review on Pubmed using 'ovarian cancer' and the name of each PARPi (PARP inhibitor) discussed in the review as Medical Subject Headings (MeSH) keywords. The same search was performed on "clinicaltrial.gov" to identify ongoing clinical trials and on "google.com/patents" and "uspto.gov" for recent patents exploring PARPIs in ovarian cancer. Olaparib, Niraparib and Rucaparib are already approved for treatment of recurrent EOC and their indications are partially overlapping. Talazoparib and Veliparib are promising PARPis, but currently under investigation in early phase trials. Several studies are evaluating PARPis in monotherapy or in associations, in a wide range of settings (i.e. first line, neoadjuvant, platinum-sensitive and resistant disease). PARPis are valuable options in patients with recurrent ovarian cancer with promising activity in different stages of this disease. Further studies are required to better define optimal clinical settings, predictors of response beyond BRCA mutations and strategies to overcome secondary resistance of PARPis therapy in EOC. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  16. On the influence of alkali metal- and alkaline earth metal chlorides on the rate on inhibition of cholinesterases by organic phosphorus inhibitors

    International Nuclear Information System (INIS)

    Brestkin, A.P.; Shataeva, G.A.

    1975-01-01

    Influence of LiCl, NaCl, KCl, RbCl, CsCl, MgCl 2 , CaCl 2 , CrCl 2 , BaCl 2 on bimolecular constant (K 2 ) of the interaction rate of acetylcholinesterazo (ACE) and butylcholinesterazo (BuCE) with phosphororganic inhibitors was studied. K 2 value with increasing of the electrolite concentration for the interaction of ACE and BuCE with charged inhibitor is significantly decreased and significantly increased in case of interaction with neutral inhibitor

  17. Synthetic peptide inhibitors of DNA replication in Staphylococcus aureus

    DEFF Research Database (Denmark)

    Løbner-Olesen, Anders; Kjelstrup, Susanne

    F counterselection was developed to directly select for compounds able to disrupt selected interactions. We have subsequently constructed a cyclic peptide library for intracellular synthesis of cyclic peptides using known technology. Several cyclic peptides were able to interfere with oligomerization of Dna......N (), DnaB and DnaX (). Three peptides identified as inhibitors of DnaN have been purified. Two of these peptides inhibited growth as well as DNA replication in S. aureus. The minimal inhibitory concentration (MIC) of the peptides was approximately 50 g/ml. Overexpression of DnaN reduced the inhibitory...

  18. Electroconvulsive therapy in patients taking monoamine oxidase inhibitors.

    Science.gov (United States)

    Dolenc, Tamara J; Habl, Samar S; Barnes, Roxann D; Rasmussen, Keith G

    2004-12-01

    Concerns have been expressed regarding the use of general anesthesia for electroconvulsive therapy (ECT) in patients taking monoamine oxidase inhibitors (MAOIs). We review the published literature and present 4 new cases and conclude that there is no evidence of a dangerous interaction between ECT and MAOI use. In general, a cautious approach would be to discontinue MAOIs before ECT if the medication has not been helpful; however, there is no need for a washout interval before starting ECT. Furthermore, if there is otherwise a reason for continuing the MAOI, it can be continued during index ECT or initiated during maintenance ECT.

  19. Discovery of a potent, dual serotonin and norepinephrine reuptake inhibitor.

    Science.gov (United States)

    Dreyfus, Nicolas; Myers, Jason K; Badescu, Valentina O; de Frutos, Oscar; de la Puente, Maria Luz; Ding, Chunjin; Filla, Sandra A; Fynboe, Karsten; Gernert, Douglas L; Heinz, Beverly A; Hemrick-Luecke, Susan K; Johnson, Kirk W; Johnson, Michael P; López, Pilar; Love, Patrick L; Martin, Laura J; Masquelin, Thierry; McCoy, Michael J; Mendiola, Javier; Morrow, Denise; Muhlhauser, Mark; Pascual, Gustavo; Perun, Thomas J; Pfeifer, Lance A; Phebus, Lee A; Richards, Simon J; Rincón, Juan Antonio; Seest, Eric P; Shah, Jikesh; Shaojuan, Jia; Simmons, Rosa Maria A; Stephenson, Gregory A; Tromiczak, Eric G; Thompson, Linda K; Walter, Magnus W; Weber, Wayne W; Zarrinmayeh, Hamideh; Thomas, Craig E; Joshi, Elizabeth; Iyengar, Smriti; Johansson, Anette M

    2013-06-13

    The objective of the described research effort was to identify a novel serotonin and norepinephrine reuptake inhibitor (SNRI) with improved norepinephrine transporter activity and acceptable metabolic stability and exhibiting minimal drug-drug interaction. We describe herein the discovery of a series of 3-substituted pyrrolidines, exemplified by compound 1. Compound 1 is a selective SNRI in vitro and in vivo, has favorable ADME properties, and retains inhibitory activity in the formalin model of pain behavior. Compound 1 thus represents a potential new probe to explore utility of SNRIs in central nervous system disorders, including chronic pain conditions.

  20. Discovery and SAR of hydantoin TACE inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Wensheng; Guo, Zhuyan; Orth, Peter; Madison, Vincent; Chen, Lei; Dai, Chaoyang; Feltz, Robert J.; Girijavallabhan, Vinay M.; Kim, Seong Heon; Kozlowski, Joseph A.; Lavey, Brian J.; Li, Dansu; Lundell, Daniel; Niu, Xiaoda; Piwinski, John J.; Popovici-Muller, Janeta; Rizvi, Razia; Rosner, Kristin E.; Shankar, Bandarpalle B.; Shih, Neng-Yang; Siddiqui, M.A.; Sun, J.; Tong, L.; Umland, S.; Wong, M.K.; Yang, D.Y.; Zhou, G. (Merck)

    2010-09-03

    We disclose inhibitors of TNF-{alpha} converting enzyme (TACE) designed around a hydantoin zinc binding moiety. Crystal structures of inhibitors bound to TACE revealed monodentate coordination of the hydantoin to the zinc. SAR, X-ray, and modeling designs are described. To our knowledge, these are the first reported X-ray structures of TACE with a hydantoin zinc ligand.

  1. Does plasminogen activator inhibitor-1 drive lymphangiogenesis?

    DEFF Research Database (Denmark)

    Bruyère, Françoise; Melen-Lamalle, Laurence; Blacher, Silvia

    2010-01-01

    The purpose of this study is to explore the function of plasminogen activator inhibitor-1 (PAI-1) during pathological lymphangiogenesis. PAI-1, the main physiological inhibitor of plasminogen activators is involved in pathological angiogenesis at least by controlling extracellular proteolysis and...

  2. Electrochemical Behaviour of Environmentally Friendly Inhibitor of ...

    African Journals Online (AJOL)

    Electrochemical Behaviour of Environmentally Friendly Inhibitor of Aloe Secundiflora Extract in Corrosion Control of Carbon Steel in Soft Water Media. ... The investigation was performed at different inhibitor concentrations under static and dynamic conditions using a Rotating Disk Electrode (RDE). The impedance and ...

  3. New pyridine derivatives as inhibitors of acetylcholinesterase and amyloid aggregation.

    Science.gov (United States)

    Pandolfi, Fabiana; De Vita, Daniela; Bortolami, Martina; Coluccia, Antonio; Di Santo, Roberto; Costi, Roberta; Andrisano, Vincenza; Alabiso, Francesco; Bergamini, Christian; Fato, Romana; Bartolini, Manuela; Scipione, Luigi

    2017-12-01

    A new series of pyridine derivatives with carbamic or amidic function has been designed and synthesized to act as cholinesterase inhibitors. The synthesized compounds were tested toward EeAChE and hAChE and toward eqBChE and hBChE. The carbamate 8 was the most potent hAChE inhibitor (IC 50  = 0.153 ± 0.016 μM) while the carbamate 11 was the most potent inhibitor of hBChE (IC 50  = 0.828 ± 0.067 μM). A molecular docking study indicated that the carbamate 8 was able to bind AChE by interacting with both CAS and PAS, in agreement with the mixed inhibition mechanism. Furthermore, the carbamates 8, 9 and 11 were able to inhibit Aβ 42 self-aggregation and possessed quite low toxicity against human astrocytoma T67 and HeLa cell lines, being the carbamate 8 the less toxic compound on both cell lines. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  4. Multimerized CHR-derived peptides as HIV-1 fusion inhibitors.

    Science.gov (United States)

    Nomura, Wataru; Hashimoto, Chie; Suzuki, Takaharu; Ohashi, Nami; Fujino, Masayuki; Murakami, Tsutomu; Yamamoto, Naoki; Tamamura, Hirokazu

    2013-08-01

    To date, several HIV-1 fusion inhibitors based on the carboxy-terminal leucine/isoleucine heptad repeat (CHR) region of an HIV-1 envelope protein gp41 have been discovered. We have shown that a synthetic peptide mimetic of a trimer form of the CHR-derived peptide C34 has potent inhibitory activity against the HIV-1 fusion mechanism, compared to a monomer C34 peptide. The present study revealed that a dimeric form of C34 is evidently structurally critical for fusion inhibitors, and that the activity of multimerized CHR-derived peptides in fusion inhibition is affected by the properties of the unit peptides C34, SC34EK, and T20. The fluorescence-based study suggested that the N36-interactive sites of the C34 trimer, including hydrophobic residues, are exposed outside the trimer and that trimerization of C34 caused a remarkable increase in fusion inhibitory activity. The present results could be useful in the design of fusion inhibitors against viral infections which proceed via membrane fusion with host cells. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  5. 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

  6. Adsorptive detoxification of fermentation inhibitors in acid pretreated liquor using functionalized polymer designed by molecular simulation.

    Science.gov (United States)

    Devendra, Leena P; Pandey, Ashok

    2017-11-01

    Acid pretreatment is the most common method employed in the lignocellulosic biorefinery leading to the separation of pentose and hexose sugar. The liquor obtained after pretreatment (acid pretreatment liquor or APL) needs to be detoxified prior to fermentation. The aim of this study was to design functional groups on a polymer matrix which are selective in their interaction to inhibitors with little or no specificity to sugars. Molecular modeling was used as a tool to design a suitable adsorbent for selective adsorption of inhibitors from a complex mixture of APL. Phenyl glycine-p-sulfonic acid loaded on chloromethylated polystyrene polymer was designed as an adsorbent for selective interaction with inhibitors. Experimental verification of the selectivity was successfully achieved. The current study provides insights on the adsorptive separation processes at the molecular level by design of specific adsorbent which can be tailor made for the better selectivity of the desired component.

  7. Condensed Tannins from Longan Bark as Inhibitor of Tyrosinase: Structure, Activity, and Mechanism.

    Science.gov (United States)

    Chai, Wei-Ming; Huang, Qian; Lin, Mei-Zhen; Ou-Yang, Chong; Huang, Wen-Yang; Wang, Ying-Xia; Xu, Kai-Li; Feng, Hui-Ling

    2018-01-31

    In this study, the content, structure, antityrosinase activity, and mechanism of longan bark condensed tannins were evaluated. The findings obtained from mass spectrometry demonstrated that longan bark condensed tannins were mixtures of procyanidins, propelargonidins, prodelphinidins, and their acyl derivatives (galloyl and p-hydroxybenzoate). The enzyme analysis indicated that these mixtures were efficient, reversible, and mixed (competitive is dominant) inhibitor of tyrosinase. What's more, the mixtures showed good inhibitions on proliferation, intracellular enzyme activity and melanogenesis of mouse melanoma cells (B 16 ). From molecular docking, the results showed the interactions between inhibitors and tyrosinase were driven by hydrogen bond, electrostatic, and hydrophobic interactions. In addition, high levels of total phenolic and extractable condensed tannins suggested that longan bark might be a good source of tyrosinase inhibitor. This study would offer theoretical basis for the development of longan bark condensed tannins as novel food preservatives and medicines of skin diseases.

  8. Virtual Screening of Novel Glucosamine-6-Phosphate Synthase Inhibitors.

    Science.gov (United States)

    Lather, Amit; Sharma, Sunil; Khatkar, Anurag

    2018-01-01

    affinities and interaction between the inhibitors and the target proteins (G-6-P synthase) by using Glide software (Schrodinger Inc. U.S.A.-Maestro version 10.2). Grid-based Ligand Docking with Energetic (Glide) is one of the most accurate docking softwares available for ligand-protein, protein-protein binding studies. A library of hundreds of available ligands was docked against targeted proteins G-6-P synthase having PDB ID 1moq. Results of docking are shown in Table 1 and Table 2. Results of G-6-P synthase docking showed that some compounds were found to have comparable docking score and binding energy (kj/mol) as compared to standard antibiotics. Many of the ligands showed hydrogen bond interaction, hydrophobic interactions, electrostatic interactions, ionic interactions and π- π stacking with the various amino acid residues in the binding pockets of G-6-P synthase. The docking study estimated free energy of binding, binding pose andglide score and all these parameters provide a promising tool for the discovery of new potent natural inhibitors of G-6-P synthase. These G-6-P synthase inhibitors could further be used as antimicrobials. Here, a detailed binding analysis and new insights of inhibitors from various classes of molecules were docked in binding cavity of G-6-P synthase. ADME and toxicity prediction of these compounds will further accentuate us to study these compounds in vivo. This information will possibly present further expansion of effective antimicrobials against several microbial infections. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. Potential physiological role of plant glycosidase inhibitors

    DEFF Research Database (Denmark)

    Bellincampi, D.; Carmadella, L.; Delcour, J.A.

    2004-01-01

    Carbohydrate-active enzymes including glycosidases, transglycosidases, glycosyltransferases, polysaccharide lyases and carbohydrate esterases are responsible for the enzymatic processing of carbohydrates in plants. A number of carbohydrate-active enzymes are produced by microbial pathogens...... and insects responsible of severe crop losses. Plants have evolved proteinaceous inhibitors to modulate the activity of several of these enzymes. The continuing discovery of new inhibitors indicates that this research area is still unexplored and may lead to new exciting developments. To date, the role...... of the inhibitors is not completely understood. Here we review recent results obtained on the best characterised inhibitors, pointing to their possible biological role in vivo. Results recently obtained with plant transformation technology indicate that this class of inhibitors has potential biotechnological...

  10. USING A DOE AND EIS TO EVALUATE THE SYNERGISTIC EFFECTS OF LOW TOXICITY INHIBITORS FOR MILD STEEL

    Directory of Open Access Journals (Sweden)

    G. V. Bueno

    2015-03-01

    Full Text Available Abstract Inhibitors are widely used to prevent corrosion in cooling-water systems, and their protective performance can be enhanced by combination. The aim of this paper is to identify possible synergistic effects between four low toxicity substances used as corrosion inhibitors for mild steel in industrial cooling-water systems. Electrochemical measurements were obtained following a design of experiments (DOE where the independent variables were the inhibitors concentrations and the response variable the charge transfer resistance estimated from impedance diagrams. Potentiodynamic polarization curves show that all of them act as anodic corrosion inhibitors. Among the tested formulations, only the interaction between sodium molybdate and sodium tungstate showed statistically significant effects, indicating that they can perform better when used together. The results of this work show the importance of using a statistical tool when designing inhibitor mixtures.

  11. The HIV-1 integrase-LEDGF allosteric inhibitor MUT-A: resistance profile, impairment of virus maturation and infectivity but without influence on RNA packaging or virus immunoreactivity

    NARCIS (Netherlands)

    Amadori, Céline; Ubeles van der Velden, Yme; Bonnard, Damien; Orlov, Igor; van Bel, Nikki; Le Rouzic, Erwann; Miralles, Laia; Brias, Julie; Chevreuil, Francis; Spehner, Daniele; Chasset, Sophie; Ledoussal, Benoit; Mayr, Luzia; Moreau, François; García, Felipe; Gatell, José; Zamborlini, Alessia; Emiliani, Stéphane; Ruff, Marc; Klaholz, Bruno P.; Moog, Christiane; Berkhout, Ben; Plana, Montserrat; Benarous, Richard

    2017-01-01

    HIV-1 Integrase (IN) interacts with the cellular co-factor LEDGF/p75 and tethers the HIV preintegration complex to the host genome enabling integration. Recently a new class of IN inhibitors was described, the IN-LEDGF allosteric inhibitors (INLAIs). Designed to interfere with the IN-LEDGF

  12. Computational Studies of Difference in Binding Modes of Peptide and Non-Peptide Inhibitors to MDM2/MDMX Based on Molecular Dynamics Simulations

    Directory of Open Access Journals (Sweden)

    Yuxin Zhang

    2012-02-01

    Full Text Available Inhibition of p53-MDM2/MDMX interaction is considered to be a promising strategy for anticancer drug design to activate wild-type p53 in tumors. We carry out molecular dynamics (MD simulations to study the binding mechanisms of peptide and non-peptide inhibitors to MDM2/MDMX. The rank of binding free energies calculated by molecular mechanics generalized Born surface area (MM-GBSA method agrees with one of the experimental values. The results suggest that van der Waals energy drives two kinds of inhibitors to MDM2/MDMX. We also find that the peptide inhibitors can produce more interaction contacts with MDM2/MDMX than the non-peptide inhibitors. Binding mode predictions based on the inhibitor-residue interactions show that the π–π, CH–π and CH–CH interactions dominated by shape complimentarity, govern the binding of the inhibitors in the hydrophobic cleft of MDM2/MDMX. Our studies confirm the residue Tyr99 in MDMX can generate a steric clash with the inhibitors due to energy and structure. This finding may theoretically provide help to develop potent dual-specific or MDMX inhibitors.

  13. Therapeutic peptides for cancer therapy. Part I - peptide inhibitors of signal transduction cascades.

    Science.gov (United States)

    Bidwell, Gene L; Raucher, Drazen

    2009-10-01

    Therapeutic peptides have great potential as anticancer agents owing to their ease of rational design and target specificity. However, their utility in vivo is limited by low stability and poor tumor penetration. The authors review the development of peptide inhibitors with potential for cancer therapy. Peptides that inhibit signal transduction cascades are discussed. The authors searched Medline for articles concerning the development of therapeutic peptides and their delivery. Given our current knowledge of protein sequences, structures and interaction interfaces, therapeutic peptides that inhibit interactions of interest are easily designed. These peptides are advantageous because they are highly specific for the interaction of interest, and they are much more easily developed than small molecule inhibitors of the same interactions. The main hurdle to application of peptides for cancer therapy is their poor pharmacokinetic and biodistribution parameters. Therefore, successful development of peptide delivery vectors could potentially make possible the use of this new and very promising class of anticancer agents.

  14. The Wonders of Phosphodiesterase‑5 Inhibitors: A Majestic History

    African Journals Online (AJOL)

    A milestone in drug discovery was the selective inhibitors of. PDE‑5 that ... the pharmacotherapeutics of PDE‑5 inhibitors and the majestic history that led to their discovery. ..... including HIV protease inhibitors, ketoconazole, itraconazole,.

  15. Binding of carbohydrates and protein inhibitors to the surface of alpha-amylases

    DEFF Research Database (Denmark)

    Bozonnet, Sophie; Bønsager, Birgit Christine; Kramhoft, B.

    2005-01-01

    This review on barley alpha-amylases 1 (AMY1) and 2 (AMY2) addresses rational mutations at distal subsites to the catalytic site, polysaccharide hydrolysis, and interactions with proteinaceous inhibitors. Subsite mapping of barley alpha-amylases revealed 6 glycone and 4 aglycone substrate subsite...

  16. Instrumental interaction

    OpenAIRE

    Luciani , Annie

    2007-01-01

    International audience; The expression instrumental interaction as been introduced by Claude Cadoz to identify a human-object interaction during which a human manipulates a physical object - an instrument - in order to perform a manual task. Classical examples of instrumental interaction are all the professional manual tasks: playing violin, cutting fabrics by hand, moulding a paste, etc.... Instrumental interaction differs from other types of interaction (called symbolic or iconic interactio...

  17. Squash inhibitor family of serine proteinases

    International Nuclear Information System (INIS)

    Otlewski, J.; Krowarsch, D.

    1996-01-01

    Squash inhibitors of serine proteinases form an uniform family of small proteins. They are built of 27-33 amino-acid residues and cross-linked with three disulfide bridges. The reactive site peptide bond (P1-P1') is between residue 5 (Lys, Arg or Leu) and 6 (always Ile). High resolution X-ray structures are available for two squash inhibitors complexed with trypsin. NMR solution structures have also been determined for free inhibitors. The major structural motif is a distorted, triple-stranded antiparallel beta-sheet. A similar folding motif has been recently found in a number of proteins, including: conotoxins from fish-hunting snails, carboxypeptidase inhibitor from potato, kalata B1 polypeptide, and in some growth factors (e.g. nerve growth factor, transforming growth factor β2, platelet-derived growth factor). Squash inhibitors are highly stable and rigid proteins. They inhibit a number of serine proteinases: trypsin, plasmin, kallikrein, blood clotting factors: X a and XII a , cathepsin G. The inhibition spectrum can be much broadened if specific amino-acid substitutions are introduced, especially at residues which contact proteinase. Squash inhibitors inhibit proteinases via the standard mechanism. According to the mechanism, inhibitors are substrates which exhibit at neutral pH a high k cat /K m index for hydrolysis and resynthesis of the reactive site, and a low value of the hydrolysis constant. (author)

  18. Histone Deacetylase Inhibitors as Anticancer Drugs.

    Science.gov (United States)

    Eckschlager, Tomas; Plch, Johana; Stiborova, Marie; Hrabeta, Jan

    2017-07-01

    Carcinogenesis cannot be explained only by genetic alterations, but also involves epigenetic processes. Modification of histones by acetylation plays a key role in epigenetic regulation of gene expression and is controlled by the balance between histone deacetylases (HDAC) and histone acetyltransferases (HAT). HDAC inhibitors induce cancer cell cycle arrest, differentiation and cell death, reduce angiogenesis and modulate immune response. Mechanisms of anticancer effects of HDAC inhibitors are not uniform; they may be different and depend on the cancer type, HDAC inhibitors, doses, etc. HDAC inhibitors seem to be promising anti-cancer drugs particularly in the combination with other anti-cancer drugs and/or radiotherapy. HDAC inhibitors vorinostat, romidepsin and belinostat have been approved for some T-cell lymphoma and panobinostat for multiple myeloma. Other HDAC inhibitors are in clinical trials for the treatment of hematological and solid malignancies. The results of such studies are promising but further larger studies are needed. Because of the reversibility of epigenetic changes during cancer development, the potency of epigenetic therapies seems to be of great importance. Here, we summarize the data on different classes of HDAC inhibitors, mechanisms of their actions and discuss novel results of preclinical and clinical studies, including the combination with other therapeutic modalities.

  19. Histone Deacetylase Inhibitors as Anticancer Drugs

    Directory of Open Access Journals (Sweden)

    Tomas Eckschlager

    2017-07-01

    Full Text Available Carcinogenesis cannot be explained only by genetic alterations, but also involves epigenetic processes. Modification of histones by acetylation plays a key role in epigenetic regulation of gene expression and is controlled by the balance between histone deacetylases (HDAC and histone acetyltransferases (HAT. HDAC inhibitors induce cancer cell cycle arrest, differentiation and cell death, reduce angiogenesis and modulate immune response. Mechanisms of anticancer effects of HDAC inhibitors are not uniform; they may be different and depend on the cancer type, HDAC inhibitors, doses, etc. HDAC inhibitors seem to be promising anti-cancer drugs particularly in the combination with other anti-cancer drugs and/or radiotherapy. HDAC inhibitors vorinostat, romidepsin and belinostat have been approved for some T-cell lymphoma and panobinostat for multiple myeloma. Other HDAC inhibitors are in clinical trials for the treatment of hematological and solid malignancies. The results of such studies are promising but further larger studies are needed. Because of the reversibility of epigenetic changes during cancer development, the potency of epigenetic therapies seems to be of great importance. Here, we summarize the data on different classes of HDAC inhibitors, mechanisms of their actions and discuss novel results of preclinical and clinical studies, including the combination with other therapeutic modalities.

  20. Reverse transcriptase inhibitors as microbicides.

    Science.gov (United States)

    Lewi, Paul; Heeres, Jan; Ariën, Kevin; Venkatraj, Muthusamy; Joossens, Jurgen; Van der Veken, Pieter; Augustyns, Koen; Vanham, Guido

    2012-01-01

    The CAPRISA 004 study in South Africa has accelerated the development of vaginal and rectal microbicides containing antiretrovirals that target specific enzymes in the reproduction cycle of HIV, especially reverse transcriptase inhibitors (RTI). In this review we discuss the potential relevance of HIV-1 RTIs as microbicides, focusing in the nucleotide RTI tenofovir and six classes of nonnucleoside RTIs (including dapivirine, UC781, urea and thiourea PETTs, DABOs and a pyrimidinedione). Although tenofovir and dapivirine appear to be most advanced in clinical trials as potential microbicides, several issues remain unresolved, e.g., the importance of nonhuman primates as a "gatekeeper" for clinical trials, the emergence and spread of drug-resistant mutants, the combination of microbicides that target different phases of viral reproduction and the accessibility to microbicides in low-income countries. Thus, here we discuss the latest research on RTI as microbicides in the light of the continuing spread of the HIV pandemic from the point of view of medicinal chemistry, virological, and pharmaceutical studies.

  1. AZT as a telomerase inhibitor

    International Nuclear Information System (INIS)

    Gomez, Daniel E.; Armando, Romina G.; Alonso, Daniel F.

    2012-01-01

    Telomerase is a highly specialized reverse transcriptase (RT) and the maintenance of telomeric length is determined by this specific enzyme. The human holoenzyme telomerase is a ribonucleoprotein composed by a catalytic subunit, hTERT, an RNA component, hTR, and a group of associated proteins. Telomerase is normally expressed in embryonic cells and is repressed during adulthood. The enzyme is reexpressed in around 85% of solid tumors. This observation makes it a potential target for developing drugs that could be developed for therapeutic purposes. The identification of the hTERT as a functional catalytic RT prompted studies of inhibiting telomerase with the HIV RT inhibitor azidothymidine (AZT). Previously, we have demonstrated that AZT binds preferentially to telomeres, inhibits telomerase and enhances tumor cell senescence, and apoptosis after AZT treatment in breast mammary adenocarcinoma cells. Since then, several studies have considered AZT for telomerase inhibition and have led to potential clinical strategies for anticancer therapy. This review covers present thinking of the inhibition of telomerase by AZT and future treatment protocols using the drug.

  2. Proton pump inhibitors and gastroenteritis

    International Nuclear Information System (INIS)

    Hassing, Robert-Jan; Verbon, Annelies; Visser, Herman de; Hofman, Albert; Stricker, Bruno H.

    2016-01-01

    An association between proton pump inhibitor (PPI) therapy and bacterial gastroenteritis has been suggested as well as contradicted. The aim of this study was to examine the association between the use of PPIs and occurrence of bacterial gastroenteritis in the prospective Rotterdam Study. The Rotterdam Study is a population-based cohort study among 14,926 subjects aged 45 years and older with up to 24 years of follow-up. Analyses were performed with a generalized estimating equations method in participants who handed-in a diagnostic stool sample. Furthermore, a nested case–control analysis was performed using the total cohort as a reference group. A bacterial microorganism was isolated in 125 samples, whereas 1174 samples were culture negative. In the generalized estimating equations analysis, we found that participants with a bacterial gastroenteritis were more likely than controls to be current users of PPIs (adjusted OR 1.94; 95 % CI 1.15–3.25). Different sensitivity analyses did not change this result. A considerably higher effect was observed (adjusted OR 6.14; 95 % CI 3.81–9.91), using the total cohort as a reference in a nested case–control analysis. Current PPI therapy is associated with an increased risk of bacterial gastroenteritis. However, by reducing the risk of selection and information bias in our study design, we demonstrated that the effect is lower than previously assumed.

  3. ALK inhibitors, a pharmaceutical perspective

    Directory of Open Access Journals (Sweden)

    Arturo eGalvani

    2012-02-01

    Full Text Available In 2007, the ALK tyrosine kinase, already known to be translocated and activated in Anaplastic Large Cell Lymphoma, and a few other rare cancers, was described as a potential therapeutic target for a subset of non small-cell lung cancer (NSCLC patients. Clinical proof of concept, culminating in the recent approval by the FDA of the Pfizer drug Xalkori (crizotinib, formerly known as PF-02341066 followed in record time. The drug was approved together with a companion diagnostic, the Vysis ALK Break Apart FISH Probe Kit (Abbott Molecular, Inc. for detection of eligible patients. This remarkable example of the coming of age of personalized medicine in cancer therapy is hopefully only an auspice of things to come in this rapidly developing field. Perhaps unsurprisingly, however, the appearance of clinical acquired resistance to crizotinib has already been observed early on in clinical testing, with the identification of several ALK secondary point mutations which diminish drug efficacy, and which open the way for development of second-generation inhibitors. It is also emerging that acquired resistance to crizotinib may also occur through ALK-independent mechanisms, which still need to be elucidated in detail.

  4. SGLT2 Inhibitors May Predispose to Ketoacidosis.

    Science.gov (United States)

    Taylor, Simeon I; Blau, Jenny E; Rother, Kristina I

    2015-08-01

    Sodium glucose cotransporter 2 (SGLT2) inhibitors are antidiabetic drugs that increase urinary excretion of glucose, thereby improving glycemic control and promoting weight loss. Since approval of the first-in-class drug in 2013, data have emerged suggesting that these drugs increase the risk of diabetic ketoacidosis. In May 2015, the Food and Drug Administration issued a warning that SGLT2 inhibitors may lead to ketoacidosis. Using PubMed and Google, we conducted Boolean searches including terms related to ketone bodies or ketoacidosis with terms for SGLT2 inhibitors or phlorizin. Priority was assigned to publications that shed light on molecular mechanisms whereby SGLT2 inhibitors could affect ketone body metabolism. SGLT2 inhibitors trigger multiple mechanisms that could predispose to diabetic ketoacidosis. When SGLT2 inhibitors are combined with insulin, it is often necessary to decrease the insulin dose to avoid hypoglycemia. The lower dose of insulin may be insufficient to suppress lipolysis and ketogenesis. Furthermore, SGLT2 is expressed in pancreatic α-cells, and SGLT2 inhibitors promote glucagon secretion. Finally, phlorizin, a nonselective inhibitor of SGLT family transporters decreases urinary excretion of ketone bodies. A decrease in the renal clearance of ketone bodies could also increase the plasma ketone body levels. Based on the physiology of SGLT2 and the pharmacology of SGLT2 inhibitors, there are several biologically plausible mechanisms whereby this class of drugs has the potential to increase the risk of developing diabetic ketoacidosis. Future research should be directed toward identifying which patients are at greatest risk for this side effect and also to optimizing pharmacotherapy to minimize the risk to patients.

  5. ACE Inhibitor-Induced Angioedema of the Intestine: Case Report, Incidence, Pathophysiology, Diagnosis and Management

    Directory of Open Access Journals (Sweden)

    Gavin Oudit

    2001-01-01

    Full Text Available A case report of fosinopril-induced angioedema of the intestine with a chronic course accompanied by multiple acute exacerbations is described. Angiotensin-converting enzyme (ACE inhibitor-induced angioedema of the intestine (AIAI occurs in a minority of patients taking an ACE inhibitor. The clinical presentation encompasses acute abdominal symptoms, pronounced bowel edema and ascites with occasional facial and/or oropharyngeal swelling. AIAI is diagnosed based on the temporal relationship between the symptomatic presentation and drug use, absence of alternative diagnoses including other causes of angioedema, and the prompt resolution of symptoms upon discontinuation of the ACE inhibitor. Prompt radiological investigation (abdominal computerized tomography and/or ultrasound is critical in making an early diagnosis and in preventing unnecessary surgical intervention. There is a female predominance of AIAI, which may reflect the interaction of estradiol with the various pathways involved in the pathophysiology of AIAI. Management of AIAI consists mainly of conservative measures and discontinuation of the ACE inhibitor. Angiotensin II receptor antagonists should not be considered as appropriate alternatives. Awareness and knowledge of AIAI are important because of the increasing use of ACE inhibitors, current delays in making the diagnosis, obvious management strategies once the diagnosis is made and the dysutility of alternative diagnoses, which may lead to considerable morbidity. AIAI must be considered in patients taking ACE inhibitors who develop gastrointestinal complaints irrespective of the duration of the therapy.

  6. 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.

  7. Effective DNA Inhibitors of Cathepsin G by In Vitro Selection

    Science.gov (United States)

    Gatto, Barbara; Vianini, Elena; Lucatello, Lorena; Sissi, Claudia; Moltrasio, Danilo; Pescador, Rodolfo; Porta, Roberto; Palumbo, Manlio

    2008-01-01

    Cathepsin G (CatG) is a chymotrypsin-like protease released upon degranulation of neutrophils. In several inflammatory and ischaemic diseases the impaired balance between CatG and its physiological inhibitors leads to tissue destruction and platelet aggregation. Inhibitors of CatG are suitable for the treatment of inflammatory diseases and procoagulant conditions. DNA released upon the death of neutrophils at injury sites binds CatG. Moreover, short DNA fragments are more inhibitory than genomic DNA. Defibrotide, a single stranded polydeoxyribonucleotide with antithrombotic effect is also a potent CatG inhibitor. Given the above experimental evidences we employed a selection protocol to assess whether DNA inhibition of CatG may be ascribed to specific sequences present in defibrotide DNA. A Selex protocol was applied to identify the single-stranded DNA sequences exhibiting the highest affinity for CatG, the diversity of a combinatorial pool of oligodeoxyribonucleotides being a good representation of the complexity found in defibrotide. Biophysical and biochemical studies confirmed that the selected sequences bind tightly to the target enzyme and also efficiently inhibit its catalytic activity. Sequence analysis carried out to unveil a motif responsible for CatG recognition showed a recurrence of alternating TG repeats in the selected CatG binders, adopting an extended conformation that grants maximal interaction with the highly charged protein surface. This unprecedented finding is validated by our results showing high affinity and inhibition of CatG by specific DNA sequences of variable length designed to maximally reduce pairing/folding interactions. PMID:19325843

  8. Effective DNA Inhibitors of Cathepsin G by In Vitro Selection

    Directory of Open Access Journals (Sweden)

    Manlio Palumbo

    2008-06-01

    Full Text Available Cathepsin G (CatG is a chymotrypsin-like protease released upon degranulation of neutrophils. In several inflammatory and ischaemic diseases the impaired balance between CatG and its physiological inhibitors leads to tissue destruction and platelet aggregation. Inhibitors of CatG are suitable for the treatment of inflammatory diseases and procoagulant conditions. DNA released upon the death of neutrophils at injury sites binds CatG. Moreover, short DNA fragments are more inhibitory than genomic DNA. Defibrotide, a single stranded polydeoxyribonucleotide with antithrombotic effect is also a potent CatG inhibitor. Given the above experimental evidences we employed a selection protocol to assess whether DNA inhibition of CatG may be ascribed to specific sequences present in defibrotide DNA. A Selex protocol was applied to identify the single-stranded DNA sequences exhibiting the highest affinity for CatG, the diversity of a combinatorial pool of oligodeoxyribonucleotides being a good representation of the complexity found in defibrotide. Biophysical and biochemical studies confirmed that the selected sequences bind tightly to the target enzyme and also efficiently inhibit its catalytic activity. Sequence analysis carried out to unveil a motif responsible for CatG recognition showed a recurrence of alternating TG repeats in the selected CatG binders, adopting an extended conformation that grants maximal interaction with the highly charged protein surface. This unprecedented finding is validated by our results showing high affinity and inhibition of CatG by specific DNA sequences of variable length designed to maximally reduce pairing/folding interactions.

  9. Structural insight into exosite binding and discovery of novel exosite inhibitors of botulinum neurotoxin serotype A through in silico screening

    Science.gov (United States)

    Hu, Xin; Legler, Patricia M.; Southall, Noel; Maloney, David J.; Simeonov, Anton; Jadhav, Ajit

    2014-07-01

    Botulinum neurotoxin serotype A (BoNT/A) is the most lethal toxin among the Tier 1 Select Agents. Development of potent and selective small molecule inhibitors against BoNT/A zinc metalloprotease remains a challenging problem due to its exceptionally large substrate binding surface and conformational plasticity. The exosites of the catalytic domain of BoNT/A are intriguing alternative sites for small molecule intervention, but their suitability for inhibitor design remains largely unexplored. In this study, we employed two recently identified exosite inhibitors, D-chicoric acid and lomofungin, to probe the structural features of the exosites and molecular mechanisms of synergistic inhibition. The results showed that D-chicoric acid favors binding at the α-exosite, whereas lomofungin preferentially binds at the β-exosite by mimicking the substrate β-sheet binding interaction. Molecular dynamics simulations and binding interaction analysis of the exosite inhibitors with BoNT/A revealed key elements and hotspots that likely contribute to the inhibitor binding and synergistic inhibition. Finally, we performed database virtual screening for novel inhibitors of BoNT/A targeting the exosites. Hits C1 and C2 showed non-competitive inhibition and likely target the α- and β-exosites, respectively. The identified exosite inhibitors may provide novel candidates for structure-based development of therapeutics against BoNT/A intoxication.

  10. Overlapping binding sites for trypsin and papain on a Kunitz-type proteinase inhibitor from Prosopis juliflora.

    Science.gov (United States)

    Franco, Octávio L; Grossi de Sá, Maria F; Sales, Maurício P; Mello, Luciane V; Oliveira, Adeliana S; Rigden, Daniel J

    2002-11-15

    Proteinase inhibitors are among the most promising candidates for expression by transgenic plants and consequent protection against insect predation. However, some insects can respond to the threat of the proteinase inhibitor by the production of enzymes insensitive to inhibition. Inhibitors combining more than one favorable activity are therefore strongly favored. Recently, a known small Kunitz trypsin inhibitor from Prosopis juliflora (PTPKI) has been shown to possess unexpected potent cysteine proteinase inhibitory activity. Here we show, by enzyme assay and gel filtration, that, unlike other Kunitz inhibitors with dual activities, this inhibitor is incapable of simultaneous inhibition of trypsin and papain. These data are most readily interpreted by proposing overlapping binding sites for the two enzymes. Molecular modeling and docking experiments favor an interaction mode in which the same inhibitor loop that interacts in a canonical fashion with trypsin can also bind into the papain catalytic site cleft. Unusual residue substitutions at the proposed interface can explain the relative rarity of twin trypsin/papain inhibition. Other changes seem responsible for the relative low affinity of PTPKI for trypsin. The predicted coincidence of trypsin and papain binding sites, once confirmed, would facilitate the search, by phage display for example, for mutants highly active against both proteinases. Copyright 2002 Wiley-Liss, Inc.

  11. An Updated Review of Tyrosinase Inhibitors

    Directory of Open Access Journals (Sweden)

    Te-Sheng Chang

    2009-05-01

    Full Text Available Tyrosinase is a multifunctional, glycosylated, and copper-containing oxidase, which catalyzes the first two steps in mammalian melanogenesis and is responsible for enzymatic browning reactions in damaged fruits during post-harvest handling and processing. Neither hyperpigmentation in human skin nor enzymatic browning in fruits are desirable. These phenomena have encouraged researchers to seek new potent tyrosinase inhibitors for use in foods and cosmetics. This article surveys tyrosinase inhibitors newly discovered from natural and synthetic sources. The inhibitory strength is compared with that of a standard inhibitor, kojic acid, and their inhibitory mechanisms are discussed.

  12. In silico prediction of ROCK II inhibitors by different classification approaches.

    Science.gov (United States)

    Cai, Chuipu; Wu, Qihui; Luo, Yunxia; Ma, Huili; Shen, Jiangang; Zhang, Yongbin; Yang, Lei; Chen, Yunbo; Wen, Zehuai; Wang, Qi

    2017-11-01

    ROCK II is an important pharmacological target linked to central nervous system disorders such as Alzheimer's disease. The purpose of this research is to generate ROCK II inhibitor prediction models by machine learning approaches. Firstly, four sets of descriptors were calculated with MOE 2010 and PaDEL-Descriptor, and optimized by F-score and linear forward selection methods. In addition, four classification algorithms were used to initially build 16 classifiers with k-nearest neighbors [Formula: see text], naïve Bayes, Random forest, and support vector machine. Furthermore, three sets of structural fingerprint descriptors were introduced to enhance the predictive capacity of classifiers, which were assessed with fivefold cross-validation, test set validation and external test set validation. The best two models, MFK + MACCS and MLR + SubFP, have both MCC values of 0.925 for external test set. After that, a privileged substructure analysis was performed to reveal common chemical features of ROCK II inhibitors. Finally, binding modes were analyzed to identify relationships between molecular descriptors and activity, while main interactions were revealed by comparing the docking interaction of the most potent and the weakest ROCK II inhibitors. To the best of our knowledge, this is the first report on ROCK II inhibitors utilizing machine learning approaches that provides a new method for discovering novel ROCK II inhibitors.

  13. Virtual Screening of Acetylcholinesterase Inhibitors Using the Lipinski’s Rule of Five and ZINC Databank

    Directory of Open Access Journals (Sweden)

    Pablo Andrei Nogara

    2015-01-01

    Full Text Available Alzheimer’s disease (AD is a progressive and neurodegenerative pathology that can affect people over 65 years of age. It causes several complications, such as behavioral changes, language deficits, depression, and memory impairments. One of the methods used to treat AD is the increase of acetylcholine (ACh in the brain by using acetylcholinesterase inhibitors (AChEIs. In this study, we used the ZINC databank and the Lipinski’s rule of five to perform a virtual screening and a molecular docking (using Auto Dock Vina 1.1.1 aiming to select possible compounds that have quaternary ammonium atom able to inhibit acetylcholinesterase (AChE activity. The molecules were obtained by screening and further in vitro assays were performed to analyze the most potent inhibitors through the IC50 value and also to describe the interaction models between inhibitors and enzyme by molecular docking. The results showed that compound D inhibited AChE activity from different vertebrate sources and butyrylcholinesterase (BChE from Equus ferus (EfBChE, with IC50 ranging from 1.69 ± 0.46 to 5.64 ± 2.47 µM. Compound D interacted with the peripheral anionic subsite in both enzymes, blocking substrate entrance to the active site. In contrast, compound C had higher specificity as inhibitor of EfBChE. In conclusion, the screening was effective in finding inhibitors of AChE and BuChE from different organisms.

  14. Inhibiting properties and adsorption of an amine based fatty acid corrosion inhibitor on carbon steel in aqueous carbon dioxide solutions

    Energy Technology Data Exchange (ETDEWEB)

    Buchweishaija, Joseph

    1997-12-31

    Carbon dioxide corrosion is a major corrosion problem in oil and gas production systems and many organic inhibitors have been tested and used to protect the substrate from corrosion. This thesis studies the mechanism of interaction of the inhibitor molecule with the metallic substrate and how this affects the dissolution rate of the metal. The performance of a commercial amine based fatty acid corrosion inhibitor has been investigated using rotating cylinder electrodes and carbon steel electrodes in CO{sub 2} saturated formation water in the temperature range between 35 to 80{sup o}C. The corrosion process was monitored by electrochemical impedance measurements, and at the end of each experiment full polarization curves were recorded. When the inhibitor was applied on noncorroded electrodes, high inhibitor performance, over 99.7%, was observed independent of temperature. On precorroded electrodes inhibitor performance was found to depend on temperature and time of precorrosion. Above 60{sup o}C, the inhibitor performance decreased with increasing time of precorrosion, presumably because of the formation of a corrosion film of either iron carbonate or a combination of iron carbonate and iron carbide which prevent the inhibitor from reaching the surface. The inhibitor protection efficiency was assumed to be associated with the degree of inhibitor coverage at the material surface, and adsorption isotherms have been calculated in the concentration range between 0.1 ppm and 100 ppm. A Langmuir isotherm was found to give the best fit. The inhibitor performance on a 2 days precorroded rotating electrode was investigated at different solution pH ranging between 4.5 and 6.5 at 35{sup o}C. 130 refs., 80 figs., 22 tabs.

  15. Small-Molecule Inhibitors of the SOX18 Transcription Factor.

    Science.gov (United States)

    Fontaine, Frank; Overman, Jeroen; Moustaqil, Mehdi; Mamidyala, Sreeman; Salim, Angela; Narasimhan, Kamesh; Prokoph, Nina; Robertson, Avril A B; Lua, Linda; Alexandrov, Kirill; Koopman, Peter; Capon, Robert J; Sierecki, Emma; Gambin, Yann; Jauch, Ralf; Cooper, Matthew A; Zuegg, Johannes; Francois, Mathias

    2017-03-16

    Pharmacological modulation of transcription factors (TFs) has only met little success over the past four decades. This is mostly due to standard drug discovery approaches centered on blocking protein/DNA binding or interfering with post-translational modifications. Recent advances in the field of TF biology have revealed a central role of protein-protein interaction in their mode of action. In an attempt to modulate the activity of SOX18 TF, a known regulator of vascular growth in development and disease, we screened a marine extract library for potential small-molecule inhibitors. We identified two compounds, which inspired a series of synthetic SOX18 inhibitors, able to interfere with the SOX18 HMG DNA-binding domain, and to disrupt HMG-dependent protein-protein interaction with RBPJ. These compounds also perturbed SOX18 transcriptional activity in a cell-based reporter gene system. This approach may prove useful in developing a new class of anti-angiogenic compounds based on the inhibition of TF activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Oral direct thrombin inhibitors or oral factor Xa inhibitors for the treatment of pulmonary embolism.

    Science.gov (United States)

    Robertson, Lindsay; Kesteven, Patrick; McCaslin, James E

    2015-12-04

    Pulmonary embolism is a potentially life-threatening condition in which a clot can travel from the deep veins, most commonly in the leg, up to the lungs. Previously, a pulmonary embolism was treated with the anticoagulants heparin and vitamin K antagonists. Recently, however, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTI) and oral factor Xa inhibitors. The new drugs have characteristics that may be favourable over conventional treatment, including oral administration, a predictable effect, lack of frequent monitoring or re-dosing and few known drug interactions. To date, no Cochrane review has measured the effectiveness and safety of these drugs in the long-term treatment (minimum duration of three months) of pulmonary embolism. To assess the effectiveness of oral DTIs and oral factor Xa inhibitors for the long-term treatment of pulmonary embolism. The Cochrane Vascular Trials Search Co-ordinator searched the Specialised Register (last searched January 2015) and the Cochrane Register of Studies (last searched January 2015). Clinical trials databases were also searched for details of ongoing or unpublished studies. We searched the reference lists of relevant articles retrieved by electronic searches for additional citations. We included randomised controlled trials in which patients with a pulmonary embolism confirmed by standard imaging techniques were allocated to receive an oral DTI or an oral factor Xa inhibitor for the long-term (minimum duration three months) treatment of pulmonary embolism. Two review authors (LR, JM) independently extracted the data and assessed the risk of bias in the trials. Any disagreements were resolved by discussion with the third author (PK). We used meta-analyses when we considered heterogeneity low. The two primary outcomes were recurrent venous thromboembolism and pulmonary embolism. Other outcomes included all-cause mortality and major bleeding. We calculated all outcomes

  17. Elucidating the structural basis for differing enzyme inhibitor potency by cryo-EM.

    Science.gov (United States)

    Rawson, Shaun; Bisson, Claudine; Hurdiss, Daniel L; Fazal, Asif; McPhillie, Martin J; Sedelnikova, Svetlana E; Baker, Patrick J; Rice, David W; Muench, Stephen P

    2018-02-20

    Histidine biosynthesis is an essential process in plants and microorganisms, making it an attractive target for the development of herbicides and antibacterial agents. Imidazoleglycerol-phosphate dehydratase (IGPD), a key enzyme within this pathway, has been biochemically characterized in both Saccharomyces cerevisiae ( Sc_ IGPD) and Arabidopsis thaliana ( At_ IGPD). The plant enzyme, having been the focus of in-depth structural analysis as part of an inhibitor development program, has revealed details about the reaction mechanism of IGPD, whereas the yeast enzyme has proven intractable to crystallography studies. The structure-activity relationship of potent triazole-phosphonate inhibitors of IGPD has been determined in both homologs, revealing that the lead inhibitor (C348) is an order of magnitude more potent against Sc_ IGPD than At_ IGPD; however, the molecular basis of this difference has not been established. Here we have used single-particle electron microscopy (EM) to study structural differences between the At and Sc_ IGPD homologs, which could influence the difference in inhibitor potency. The resulting EM maps at ∼3 Å are sufficient to de novo build the protein structure and identify the inhibitor binding site, which has been validated against the crystal structure of the At_ IGPD/C348 complex. The structure of Sc _IGPD reveals that a 24-amino acid insertion forms an extended loop region on the enzyme surface that lies adjacent to the active site, forming interactions with the substrate/inhibitor binding loop that may influence inhibitor potency. Overall, this study provides insights into the IGPD family and demonstrates the power of using an EM approach to study inhibitor binding. Copyright © 2018 the Author(s). Published by PNAS.

  18. Treatment With JAK Inhibitors in Myelofibrosis Patients Nullifies the Prognostic Impact of Unfavorable Cytogenetics.

    Science.gov (United States)

    Ma, Vincent T; Boonstra, Philip S; Menghrajani, Kamal; Perkins, Cecelia; Gowin, Krisstina L; Mesa, Ruben A; Gotlib, Jason R; Talpaz, Moshe

    2018-05-01

    In the era before Janus kinase (JAK) inhibitors, cytogenetic information was used to predict survival in myelofibrosis patients. However, the prognostic value of cytogenetics in the setting of JAK inhibitor therapy remains unknown. We performed a retrospective analysis of 180 patients with bone marrow biopsy-proven myelofibrosis from 3 US academic medical centers. We fit Cox proportional hazards models for overall survival and transformation-free survival on the bases of 3 factors: JAK inhibitor therapy as a time-dependent covariate, dichotomized cytogenetic status (favorable vs. unfavorable), and statistical interaction between the two. The median follow-up time was 37.1 months. Among patients treated with best available therapy, unfavorable cytogenetic status was associated with decreased survival (hazard ratio = 2.31; P = .025). At initiation of JAK inhibitor therapy, unfavorable cytogenetics was (nonsignificantly) associated with increased survival compared to favorable cytogenetics (hazard ratio = 0.292; P = .172). The ratio of hazard ratios was 0.126 (P = .034). These findings were similar after adjusting for standard clinical prognostic factors as well as when measured against transformation-free survival. The initiation of JAK inhibitor therapy appears to change the association between cytogenetics and overall survival. There was little difference in survival between treatment types in patients with favorable cytogenetics. However, the use of JAK inhibitor therapy among patients with unfavorable cytogenetics was not associated with worse survival compared to favorable cytogenetics. Our analyses suggest that initiation of JAK inhibitor therapy nullifies the negative prognostic implication of unfavorable cytogenetics established in the pre-JAK inhibitor therapy era. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Strategies for discontinuation of proton pump inhibitors

    DEFF Research Database (Denmark)

    Haastrup, Peter; Paulsen, Maja S; Begtrup, Luise M

    2014-01-01

    PURPOSE: Proton pump inhibitors (PPIs) are considered to be overprescribed. Consensus on how to attempt discontinuation is, however, lacking. We therefore conducted a systematic review of clinical studies on discontinuation of PPIs. METHODS: Systematic review based on clinical studies investigating...

  20. Predicting the Performance of Organic Corrosion Inhibitors

    Directory of Open Access Journals (Sweden)

    David A. Winkler

    2017-12-01

    Full Text Available The withdrawal of effective but toxic corrosion inhibitors has provided an impetus for the discovery of new, benign organic compounds to fill that role. Concurrently, developments in the high-throughput synthesis of organic compounds, the establishment of large libraries of available chemicals, accelerated corrosion inhibition testing technologies, and the increased capability of machine learning methods have made discovery of new corrosion inhibitors much faster and cheaper than it used to be. We summarize these technical developments in the corrosion inhibition field and describe how data-driven machine learning methods can generate models linking molecular properties to corrosion inhibition that can be used to predict the performance of materials not yet synthesized or tested. We briefly summarize the literature on quantitative structure–property relationships models of small organic molecule corrosion inhibitors. The success of these models provides a paradigm for rapid discovery of novel, effective corrosion inhibitors for a range of metals and alloys in diverse environments.

  1. 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.

  2. Weak interactions

    International Nuclear Information System (INIS)

    Chanda, R.

    1981-01-01

    The theoretical and experimental evidences to form a basis for Lagrangian Quantum field theory for Weak Interactions are discussed. In this context, gauge invariance aspects of such interactions are showed. (L.C.) [pt

  3. Intermolecular interactions

    International Nuclear Information System (INIS)

    Kaplan, I.G.; Rodimova, O.B.; AN SSSR, Tomsk. Inst. Optiki Atmosfery)

    1978-01-01

    The present state of the intermolecular interaction theory is described. The general physical picture of the molecular interactions is given, the relative contributions of interactions of different types are analyzed (electrostatic, resonance, induction, dispersion, relativistic, magnetostatic and exchange), and the main ones in each range of separations are picked out. The methods of the potential curve calculations are considered, specific for definite separations between the interacting systems. The special attention is paid to the analysis of approximations used in different theoretical calculation methods

  4. Monoamine Oxidase B Inhibitors in Parkinson's Disease.

    Science.gov (United States)

    Dezsi, Livia; Vecsei, Laszlo

    2017-01-01

    Parkinson's disease (PD) is a neurodegenerative disorder with a prevalence increasing with age. Oxidative stress and glutamate toxicity are involved in its pathomechanism. There are still many unmet needs of PD patients, including the alleviation of motor fluctuations and dyskinesias, and the development of therapies with neuroprotective potential. To give an overview of the pharmacological properties, the efficacy and safety of the monoamine oxidase B (MAO-B) inhibitors in the treatment of PD, with special focus on the results of randomized clinical trials. A literature search was conducted in PubMed for 'PD treatment', 'MAO-B inhibitors', 'selegiline', 'rasagiline', 'safinamide' and 'clinical trials' with 'MAO-B inhibitors' in 'Parkinson' disease'. MAO-B inhibitors have a favorable pharmacokinetic profile, improve the dopamine deficient state and may have neuroprotective properties. Safinamide exhibits an anti-glutamatergic effect as well. When applied as monotherapy, MAO-B inhibitors provide a modest, but significant improvement of motor function and delay the need for levodopa. Rasagiline and safinamide were proven safe and effective when added to a dopamine agonist in early PD. As add-on to levodopa, MAO-B inhibitors significantly reduced off-time and were comparable in efficacy to COMT inhibitors. Improvements were achieved as regards certain non-motor symptoms as well. Due to the efficacy shown in clinical trials and their favorable side-effect profile, MAO-B inhibitors are valuable drugs in the treatment of PD. They are recommended as monotherapy in the early stages of the disease and as add-on therapy to levodopa in advanced PD. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  5. The effect of chemical anti-inhibitors on fibrinolytic enzymes and inhibitors

    DEFF Research Database (Denmark)

    Sidelmann, Johannes Jakobsen; Jespersen, J; Kluft, C

    1997-01-01

    proteases. We studied the influence of chemical anti-inhibitors (chloramine T, flufenamate, sodium lauryl sulfate, and methylamine) on fibrinolytic serine proteases and fibrinolytic enzyme inhibitors using the physiological substrate fibrin as plasmin substrate. Low concentrations of chloramine T (0.01 mmol......%) and plasminogen activators (apparent recovery > 200%). Sodium lauryl sulfate eliminates the major fibrinolytic enzyme inhibitors, but increases the activity of plasmin (apparent recovery > 200%) and plasminogen activator, urokinase type (apparent recovery 130%). Methylamine affects only plasmin inhibition. We...

  6. Caprylate Salts Based on Amines as Volatile Corrosion Inhibitors for Metallic Zinc: Theoretical and Experimental Studies

    Science.gov (United States)

    Valente, Marco A. G.; Teixeira, Deiver A.; Azevedo, David L.; Feliciano, Gustavo T.; Benedetti, Assis V.; Fugivara, Cecílio S.

    2017-01-01

    The interaction of volatile corrosion inhibitors (VCI), caprylate salt derivatives from amines, with zinc metallic surfaces is assessed by density functional theory (DFT) computer simulations, electrochemical impedance (EIS) measurements and humid chamber tests. The results obtained by the different methods were compared, and linear correlations were obtained between theoretical and experimental data. The correlations between experimental and theoretical results showed that the molecular size is the determining factor in the inhibition efficiency. The models used and experimental results indicated that dicyclohexylamine caprylate is the most efficient inhibitor. PMID:28620602

  7. Development of Radiosensitizer using farnesyltransferase inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jong Seok; Choe, Yong Kyung; Han, Mi Young; Kim, Kwang Dong [Korea Research Institute of Bioscience and Biotechnology, Taejon (Korea)

    1999-03-01

    We selected some compounds that were reported to have an activity of farneyltransferase inhibitor and tested the hypothesis that they might be used to radiosensitize cells transformed by ras oncogenes. The inhibition of ras processing using some, but not all, inhibitors resulted in higher levels of cell death after {gamma}-irradiation and increased radiosensitivity in H-ras-transformed NIH3T3 cells and MCF-10A human tumor cells. They did not induce additional cell death in control cells that doe not have ras mutation. Furthermore, the treatment of inhibitors alone induced a weak G0/G1 block, whereas inhibitors in combination with {gamma}-irradiation induced an additional enrichment in the G2/M phase of the cell cycle that typically represents irradiation-induced growth arrest. At present, the underling mechanism by which the farnesylltransferase inhibitors exert radiosensitizing effect is not known. In summary, our results suggest and lead to the possibility that some of farnesylation inhibitors may prove clinically useful not only as antitumor agents, but also radiosensitizers of tumors whose growth is dependent on ras function. (author). 15 refs., 10 figs., 4 tabs.

  8. Natural inhibitors of tumor-associated proteases

    International Nuclear Information System (INIS)

    Magdolen, U.; Krol, J.; Sato, S.; Schmitt, M.; Magdolen, V.; Krueger, A.; Mueller, M.M.; Sperl, S.

    2002-01-01

    The turnover and remodelling of extracellular matrix (ECM) is an essential part of many normal biological processes including development, morphogenesis, and wound healing. ECM turnover also occurs in severe pathological situations like artherosclerosis, fibrosis, tumor invasion and metastasis. The major proteases involved in this turnover are serine proteases (especially the urokinase-type plasminogen activator/plasmin system), matrix metalloproteases (a family of about 20 zinc-dependent endopeptidases including collagenases, gelatinases, stromelysins, and membrane-type metalloproteases), and cysteine proteases. In vivo, the activity of these proteases is tightly regulated in the extracellular space by zymogen activation and/or controlled inhibition. In the present review, we give an overview on the structure and biochemical properties of important tumor-associated protease inhibitors such as plasminogen activator inhibitor type 1 and type 2 (PAI-1, PAI-2), tissue inhibitors of metalloproteinases (TIMP-1, -2, -3, and -4), and the cysteine protease inhibitor cystatin C. Interestingly, some of these inhibitors of tumor-associated proteases display multiple functions which rather promote than inhibit tumor progression, when the presence of inhibitors in the tumor tissue is not balanced. (author)

  9. Emerging Corrosion Inhibitors for Interfacial Coating

    Directory of Open Access Journals (Sweden)

    Mona Taghavikish

    2017-12-01

    Full Text Available Corrosion is a deterioration of a metal due to reaction with environment. The use of corrosion inhibitors is one of the most effective ways of protecting metal surfaces against corrosion. Their effectiveness is related to the chemical composition, their molecular structures and affinities for adsorption on the metal surface. This review focuses on the potential of ionic liquid, polyionic liquid (PIL and graphene as promising corrosion inhibitors in emerging coatings due to their remarkable properties and various embedment or fabrication strategies. The review begins with a precise description of the synthesis, characterization and structure-property-performance relationship of such inhibitors for anti-corrosion coatings. It establishes a platform for the formation of new generation of PIL based coatings and shows that PIL corrosion inhibitors with various heteroatoms in different form can be employed for corrosion protection with higher barrier properties and protection of metal surface. However, such study is still in its infancy and there is significant scope to further develop new structures of PIL based corrosion inhibitors and coatings and study their behaviour in protection of metals. Besides, it is identified that the combination of ionic liquid, PIL and graphene could possibly contribute to the development of the ultimate corrosion inhibitor based coating.

  10. Discovery of natural mouse serum derived HIV-1 entry inhibitor(s).

    Science.gov (United States)

    Wei, M; Chen, Y; Xi, J; Ru, S; Ji, M; Zhang, D; Fang, Q; Tang, B

    Among rationally designed human immunodeficiency virus 1 (HIV-1) inhibitors, diverse natural factors have showed as potent anti-HIV activity in human blood. We have discovered that the boiled supernatant of healthy mouse serum could suppress HIV-1 entry, and exhibited reduced inhibitory activity after trypsin digestion. Further analysis demonstrated that only the fraction containing 10-25 K proteins could inhibit HIV-1 mediated cell-cell fusion. These results suggest that the 10-25 K protein(s) is novel natural HIV-1 entry inhibitor(s). Our findings provide important information about novel natural HIV entry inhibitors in mouse serum.

  11. Characteristics of the Inhibition of Potato (Solanum tuberosum) Invertase by an Endogenous Proteinaceous Inhibitor in Potatoes

    Science.gov (United States)

    Bracho, Geracimo E.; Whitaker, John R.

    1990-01-01

    Effect of several parameters on inhibition of potato (Solanum tuberosum) invertase by its endogenous proteinaceous inhibitor was determined using homogeneous preparations of both proteins. The inhibitor and invertase formed an inactive complex with an observed association rate constant at pH 4.70 and 37°C of 8.82 × 102 per molar per second and a dissociation rate constant of 3.3 × 10−3 per minute. The inhibitor appeared to bind to invertase in more than one step. Initial interaction (measured by loss of invertase activity) was rapid, relatively weak, readily reversible (Ki of 2 × 10−6 molar) and noncompetitive with substrate at pH 4.70. Initial interaction was probably followed by isomerization to a tighter (Ki of 6.23 × 10−8 molar) complex, which dissociated slowly with a half-time of 3.5 hour. Interaction between enzyme and inhibitor appeared to be of ionic character and essentially pH independent between pH 3.5 and 7.4. PMID:16667286

  12. Role of gemfibrozil as an inhibitor of CYP2C8 and membrane transporters.

    Science.gov (United States)

    Tornio, Aleksi; Neuvonen, Pertti J; Niemi, Mikko; Backman, Janne T

    2017-01-01

    Cytochrome P450 (CYP) 2C8 is a drug metabolizing enzyme of major importance. The lipid-lowering drug gemfibrozil has been identified as a strong inhibitor of CYP2C8 in vivo. This effect is due to mechanism-based inhibition of CYP2C8 by gemfibrozil 1-O-β-glucuronide. In vivo, gemfibrozil is a fairly selective CYP2C8 inhibitor, which lacks significant inhibitory effect on other CYP enzymes. Gemfibrozil can, however, have a smaller but clinically meaningful inhibitory effect on membrane transporters, such as organic anion transporting polypeptide 1B1 and organic anion transporter 3. Areas covered: This review describes the inhibitory effects of gemfibrozil on CYP enzymes and membrane transporters. The clinical drug interactions caused by gemfibrozil and the different mechanisms contributing to the interactions are reviewed in detail. Expert opinion: Gemfibrozil is a useful probe inhibitor of CYP2C8 in vivo, but its effect on membrane transporters has to be taken into account in study design and interpretation. Moreover, gemfibrozil could be used to boost the pharmacokinetics of CYP2C8 substrate drugs. Identification of gemfibrozil 1-O-β-glucuronide as a potent mechanism-based inhibitor of CYP2C8 has led to recognition of glucuronide metabolites as perpetrators of drug-drug interactions. Recently, also acyl glucuronide metabolites of clopidogrel and deleobuvir have been shown to strongly inhibit CYP2C8.

  13. DRUG INTERACTIONS WITH DIAZEPAM

    Directory of Open Access Journals (Sweden)

    Zoran Bojanić

    2011-06-01

    Full Text Available Diazepam is a benzodiazepine derivative with anxyolitic, anticonvulsant, hypnotic, sedative, skeletal muscle relaxant, antitremor, and amnestic activity. It is metabolized in the liver by the cytochrome P (CYP 450 enzyme system. Diazepam is N-demethylated by CYP3A4 and CYP2C19 to the active metabolite N-desmethyldiazepam, and is hydroxylated by CYP3A4 to the active metabolite temazepam. N-desmethyl-diazepam and temazepam are both further metabolized to oxazepam. Concomitant intake of inhibitors or inducers of the CYP isozymes involved in the biotransformation of diazepam may alter plasma concentrations of this drug, although this effect is unlikely to be associated with clinically relevant interactions.The goal of this article was to review the current literature on clinically relevant pharmacokinetic drug interactions with diazepam.A search of MEDLINE and EMBASE was conducted for original research and review articles published in English between January 1971. and May 2011. Among the search terms were drug interactions, diazepam, pharmacokinetics, drug metabolism, and cytochrome P450. Only articles published in peer-reviewed journals were included, and meeting abstracts were excluded. The reference lists of relevant articles were hand-searched for additional publications.Diazepam is substantially sorbed by the plastics in flexible containers, volume control set chambers, and tubings of intravenous administration sets. Manufacturers recommend not mixing with any other drug or solution in syringe or solution, although diazepam is compatible in syringe with cimetidine and ranitidine, and in Y-site with cisatracurium, dobutamine, fentanyl, hydromorphone, methadone, morphine, nafcillin, quinidine gluconate, remifentanil, and sufentanil. Diazepam is compatible with: dextrose 5% in water, Ringers injection, Ringers injection lactated and sodium chloride 0.9%. Emulsified diazepam is compatible with Intralipid and Nutralipid.Diazepam has low potential

  14. Effective interactions

    International Nuclear Information System (INIS)

    Elliott, J.P.

    1981-01-01

    This chapter attempts to describe and compare some of the more important nucleon-nucleon interactions that have been used in nuclear structure calculations, and to relate them where possible to the real nucleon-nucleon interaction. Explains that different interactions have been used depending on whether one is fitting to total binding energies and densities with a Hartree Fock (HF) calculation or fitting to spectra and spectroscopic data in a shell model calculation. Examines both types of calculation after two preliminary sections concerned with notation and with the philosophy underlying the use of model spaces and effective interactions. Discusses Skyrme interactions, finite range interactions, small model space, large model space, and the Sussex potential matrix elements. Focuses on the more empirical approaches in which a simple form is chosen for the effective interaction in a given model space and the parameters are deduced from fitting many-body data

  15. Inactivation of proteinaceous protease inhibitors of soybeans by isolated fungi

    NARCIS (Netherlands)

    Meijer, M.M.T.; Spekking, W.T.J.; Sijtsma, L.; Bont, de J.A.M.

    1995-01-01

    Proteinaceous protease inhibitors, Kunitz Soybean Trypsin Inhibitor (KSTI) and Bowman Birk Inhibitor (BBI), in legume seeds reduce the digestibility of proteins in feed of monogastric animals. Enzymatic inactivation of these inhibitors will increase the nutritional value of the feed. The aim of this

  16. BCR-ABL1 tyrosine kinase inhibitors for the treatment of chronic myeloid leukemia.

    Science.gov (United States)

    Cuellar, Sandra; Vozniak, Michael; Rhodes, Jill; Forcello, Nicholas; Olszta, Daniel

    2017-01-01

    The management of chronic myeloid leukemia with BCR-ABL1 tyrosine kinase inhibitors has evolved chronic myeloid leukemia into a chronic, manageable disease. A patient-centered approach is important for the appropriate management of chronic myeloid leukemia and optimization of long-term treatment outcomes. The pharmacist plays a key role in treatment selection, monitoring drug-drug interactions, identification and management of adverse events, and educating patients on adherence. The combination of tyrosine kinase inhibitors with unique safety profiles and individual patients with unique medical histories can make managing treatment difficult. This review will provide up-to-date information regarding tyrosine kinase inhibitor-based treatment of patients with chronic myeloid leukemia. Management strategies for adverse events and considerations for drug-drug interactions will not only vary among patients but also across tyrosine kinase inhibitors. Drug-drug interactions can be mild to severe. In instances where co-administration of concomitant medications cannot be avoided, it is critical to understand how drug levels are impacted and how subsequent dose modifications ensure therapeutic drug levels are maintained. An important component of patient-centered management of chronic myeloid leukemia also includes educating patients on the significance of early and regular monitoring of therapeutic milestones, emphasizing the importance of adhering to treatment in achieving these targets, and appropriately modifying treatment if these clinical goals are not being met. Overall, staying apprised of current research, utilizing the close pharmacist-patient relationship, and having regular interactions with patients, will help achieve successful long-term treatment of chronic myeloid leukemia in the age of BCR-ABL1 tyrosine kinase inhibitors.

  17. 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.

  18. Hepatitis C Virus NS3/4A Protease Inhibitors Incorporating Flexible P2 Quinoxalines Target Drug Resistant Viral Variants.

    Science.gov (United States)

    Matthew, Ashley N; Zephyr, Jacqueto; Hill, Caitlin J; Jahangir, Muhammad; Newton, Alicia; Petropoulos, Christos J; Huang, Wei; Kurt-Yilmaz, Nese; Schiffer, Celia A; Ali, Akbar

    2017-07-13

    A substrate envelope-guided design strategy is reported for improving the resistance profile of HCV NS3/4A protease inhibitors. Analogues of 5172-mcP1P3 were designed by incorporating diverse quinoxalines at the P2 position that predominantly interact with the invariant catalytic triad of the protease. Exploration of structure-activity relationships showed that inhibitors with small hydrophobic substituents at the 3-position of P2 quinoxaline maintain better potency against drug resistant variants, likely due to reduced interactions with residues in the S2 subsite. In contrast, inhibitors with larger groups at this position were highly susceptible to mutations at Arg155, Ala156, and Asp168. Excitingly, several inhibitors exhibited exceptional potency profiles with EC 50 values ≤5 nM against major drug resistant HCV variants. These findings support that inhibitors designed to interact with evolutionarily constrained regions of the protease, while avoiding interactions with residues not essential for substrate recognition, are less likely to be susceptible to drug resistance.

  19. Combined effects of EGFR tyrosine kinase inhibitors and vATPase inhibitors in NSCLC cells

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hyeon-Ok [KIRAMS Radiation Biobank, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Hong, Sung-Eun [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Kim, Chang Soon [Department of Microbiological Engineering, Kon-Kuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143–701 (Korea, Republic of); Park, Jin-Ah; Kim, Jin-Hee; Kim, Ji-Young; Kim, Bora [KIRAMS Radiation Biobank, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Chang, Yoon Hwan; Hong, Seok-Il; Hong, Young Jun [Department of Laboratory Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Park, In-Chul, E-mail: parkic@kirams.re.kr [Division of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Lee, Jin Kyung, E-mail: jklee@kirams.re.kr [KIRAMS Radiation Biobank, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of); Department of Laboratory Medicine, Korea Cancer Center Hospital, Korea Institute of Radiological and Medical Sciences, 75 Nowon-ro, Nowon-gu, Seoul, 139–706 (Korea, Republic of)

    2015-08-15

    Despite excellent initial clinical responses of non-small cell lung cancer (NSCLC) patients to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), many patients eventually develop resistance. According to a recent report, vacuolar H + ATPase (vATPase) is overexpressed and is associated with chemotherapy drug resistance in NSCLC. We investigated the combined effects of EGFR TKIs and vATPase inhibitors and their underlying mechanisms in the regulation of NSCLC cell death. We found that combined treatment with EGFR TKIs (erlotinib, gefitinib, or lapatinib) and vATPase inhibitors (bafilomycin A1 or concanamycin A) enhanced synergistic cell death compared to treatments with each drug alone. Treatment with bafilomycin A1 or concanamycin A led to the induction of Bnip3 expression in an Hif-1α dependent manner. Knock-down of Hif-1α or Bnip3 by siRNA further enhanced cell death induced by bafilomycin A1, suggesting that Hif-1α/Bnip3 induction promoted resistance to cell death induced by the vATPase inhibitors. EGFR TKIs suppressed Hif-1α and Bnip3 expression induced by the vATPase inhibitors, suggesting that they enhanced the sensitivity of the cells to these inhibitors by decreasing Hif-1α/Bnip3 expression. Taken together, we conclude that EGFR TKIs enhance the sensitivity of NSCLC cells to vATPase inhibitors by decreasing Hif-1α/Bnip3 expression. We suggest that combined treatment with EGFR TKIs and vATPase inhibitors is potentially effective for the treatment of NSCLC. - Highlights: • Co-treatment with EGFR TKIs and vATPase inhibitors induces synergistic cell death • EGFR TKIs enhance cell sensitivity to vATPase inhibitors via Hif-1α downregulation • Co-treatment of these inhibitors is potentially effective for the treatment of NSCLC.

  20. Screening of protein kinase inhibitors identifies PKC inhibitors as inhibitors of osteoclastic acid secretion and bone resorption

    Directory of Open Access Journals (Sweden)

    Boutin Jean A

    2010-10-01

    Full Text Available Abstract Background Bone resorption is initiated by osteoclastic acidification of the resorption lacunae. This process is mediated by secretion of protons through the V-ATPase and chloride through the chloride antiporter ClC-7. To shed light on the intracellular signalling controlling extracellular acidification, we screened a protein kinase inhibitor library in human osteoclasts. Methods Human osteoclasts were generated from CD14+ monocytes. The effect of different kinase inhibitors on lysosomal acidification in human osteoclasts was investigated using acridine orange for different incubation times (45 minutes, 4 and 24 hours. The inhibitors were tested in an acid influx assay using microsomes isolated from human osteoclasts. Bone resorption by human osteoclasts on bone slices was measured by calcium release. Cell viability was measured using AlamarBlue. Results Of the 51 compounds investigated only few inhibitors were positive in both acidification and resorption assays. Rottlerin, GF109203X, Hypericin and Ro31-8220 inhibited acid influx in microsomes and bone resorption, while Sphingosine and Palmitoyl-DL-carnitine-Cl showed low levels of inhibition. Rottlerin inhibited lysosomal acidification in human osteoclasts potently. Conclusions In conclusion, a group of inhibitors all indicated to inhibit PKC reduced acidification in human osteoclasts, and thereby bone resorption, indicating that acid secretion by osteoclasts may be specifically regulated by PKC in osteoclasts.

  1. Selectivity of phenothiazine cholinesterase inhibitors for neurotransmitter systems.

    Science.gov (United States)

    Darvesh, Sultan; Macdonald, Ian R; Martin, Earl

    2013-07-01

    Synthetic derivatives of phenothiazine have been used for over a century as well-tolerated drugs against a variety of human ailments from psychosis to cancer. This implies a considerable diversity in the mechanisms of action produced by structural changes to the phenothiazine scaffold. For example, chlorpromazine treatment of psychosis is related to its interaction with dopaminergic receptors. On the other hand, antagonistic action of such drugs on cholinergic receptor systems would be counter-productive for treatment of Alzheimer's disease. In a search for phenothiazines that are inhibitors of cholinesterases, especially butyrylcholinesterase, with potential to treat Alzheimer's disease, we wished to ascertain that such molecules could be devoid of neurotransmitter receptor interactions. To that end, a number of our synthetic N-10-carbonyl phenothiazine derivatives, with cholinesterase inhibitory activity, were tested for interaction with a variety of neurotransmitter receptor systems. We demonstrate that phenothiazines can be prepared without significant neurotransmitter receptor interactions while retaining high potency as cholinesterase ligands for treatment of Alzheimer's disease. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Clinical pharmacology profile of vorinostat, a histone deacetylase inhibitor.

    Science.gov (United States)

    Iwamoto, Marian; Friedman, Evan J; Sandhu, Punam; Agrawal, Nancy G B; Rubin, Eric H; Wagner, John A

    2013-09-01

    Vorinostat is a histone deacetylase inhibitor that has demonstrated preclinical activity in numerous cancer models. Clinical activity has been demonstrated in patients with a variety of malignancies. Vorinostat is presently indicated for the treatment of patients with advanced cutaneous T cell lymphoma (CTCL). Clinical investigation is ongoing for therapy of other solid tumors and hematological malignancies either as monotherapy or in combination with other chemotherapeutic agents. This review summarizes the pharmacokinetic properties of vorinostat. Monotherapy pharmacokinetic data across a number of pharmacokinetic studies were reviewed, and data are presented. In addition, literature review was performed to obtain published Phase I and II pharmacokinetic combination therapy data to identify and characterize potential drug interactions with vorinostat. Pharmacokinetic data in special populations were also reviewed. The clinical pharmacology profile of vorinostat is favorable, exhibiting dose-proportional pharmacokinetics and modest food effect. There appear to be no major differences in the pharmacokinetics of vorinostat in special populations, including varying demographics and hepatic dysfunction. Combination therapy pharmacokinetic data indicate that vorinostat has a low propensity for drug interactions. Vorinostat's favorable clinical pharmacology and drug interaction profile aid in the ease of administration of vorinostat for the treatment of advanced CTCL and will be beneficial in continued assessment for other oncologic indications. Although a number of studies have been conducted to elucidate the detailed pharmacokinetic profile of vorinostat, more rigorous assessment of vorinostat pharmacokinetics, including clinical drug interaction studies, will be informative.

  3. Evolution of inhibitor-resistant natural mutant forms of HIV-1 protease probed by pre-steady state kinetic analysis.

    Science.gov (United States)

    Zakharova, Maria Yu; Kuznetsova, Alexandra A; Kaliberda, Elena N; Dronina, Maria A; Kolesnikov, Alexander V; Kozyr, Arina V; Smirnov, Ivan V; Rumsh, Lev D; Fedorova, Olga S; Knorre, Dmitry G; Gabibov, Alexander G; Kuznetsov, Nikita A

    2017-11-01

    Pre-steady state kinetic analysis of mechanistic features of substrate binding and processing is crucial for insight into the evolution of inhibitor-resistant forms of HIV-1 protease. These data may provide a correct vector for rational drug design assuming possible intrinsic dynamic effects. These data should also give some clues to the molecular mechanism of protease action and resistance to inhibitors. Here we report pre-steady state kinetics of the interaction of wild type or mutant forms of HIV-1 protease with a FRET-labeled peptide. The three-stage "minimal" kinetic scheme with first and second reversible steps of substrate binding and with following irreversible peptide cleavage step adequately described experimental data. For the first time, a set of "elementary" kinetic parameters of wild type HIV-1 protease and its natural mutant inhibitor-resistant forms MDR-HM, ANAM-11 and prDRV4 were compared. Inhibitors of the first and second generation were used to estimate the inhibitory effects on HIV-1 protease activity. The resulting set of kinetic data supported that the mutant forms are kinetically unaffected by inhibitors of the first generation, proving their functional resistance to these compounds. The second generation inhibitor darunavir inhibited mutant forms MDR-HM and ANAM-11, but was ineffective against prDRV4. Our kinetic data revealed that these inhibitors induced different conformational changes in the enzyme and, thereby they have different mode of binding in the enzyme active site. These data confirmed hypothesis that the driving force of the inhibitor-resistance evolution is disruption of enzyme-inhibitor complex by changing of the contact network in the inhibitor binding site. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  4. SGLT2 Inhibitors and the Diabetic Kidney.

    Science.gov (United States)

    Fioretto, Paola; Zambon, Alberto; Rossato, Marco; Busetto, Luca; Vettor, Roberto

    2016-08-01

    Diabetic nephropathy (DN) is the most common cause of end-stage renal disease worldwide. Blood glucose and blood pressure control reduce the risk of developing this complication; however, once DN is established, it is only possible to slow progression. Sodium-glucose cotransporter 2 (SGLT2) inhibitors, the most recent glucose-lowering oral agents, may have the potential to exert nephroprotection not only through improving glycemic control but also through glucose-independent effects, such as blood pressure-lowering and direct renal effects. It is important to consider, however, that in patients with impaired renal function, given their mode of action, SGLT2 inhibitors are less effective in lowering blood glucose. In patients with high cardiovascular risk, the SGLT2 inhibitor empagliflozin lowered the rate of cardiovascular events, especially cardiovascular death, and substantially reduced important renal outcomes. Such benefits on DN could derive from effects beyond glycemia. Glomerular hyperfiltration is a potential risk factor for DN. In addition to the activation of the renin-angiotensin-aldosterone system, renal tubular factors, including SGLT2, contribute to glomerular hyperfiltration in diabetes. SGLT2 inhibitors reduce sodium reabsorption in the proximal tubule, causing, through tubuloglomerular feedback, afferent arteriole vasoconstriction and reduction in hyperfiltration. Experimental studies showed that SGLT2 inhibitors reduced hyperfiltration and decreased inflammatory and fibrotic responses of proximal tubular cells. SGLT2 inhibitors reduced glomerular hyperfiltration in patients with type 1 diabetes, and in patients with type 2 diabetes, they caused transient acute reductions in glomerular filtration rate, followed by a progressive recovery and stabilization of renal function. Interestingly, recent studies consistently demonstrated a reduction in albuminuria. Although these data are promising, only dedicated renal outcome trials will clarify whether

  5. Design of inhibitors of thymidylate kinase from Variola virus as new selective drugs against smallpox.

    Science.gov (United States)

    Guimarães, Ana P; de Souza, Felipe R; Oliveira, Aline A; Gonçalves, Arlan S; de Alencastro, Ricardo B; Ramalho, Teodorico C; França, Tanos C C

    2015-02-16

    Recently we constructed a homology model of the enzyme thymidylate kinase from Variola virus (VarTMPK) and proposed it as a new target to the drug design against smallpox. In the present work, we used the antivirals cidofovir and acyclovir as reference compounds to choose eleven compounds as leads to the drug design of inhibitors for VarTMPK. Docking and molecular dynamics (MD) studies of the interactions of these compounds inside VarTMPK and human TMPK (HssTMPK) suggest that they compete for the binding region of the substrate and were used to propose the structures of ten new inhibitors for VarTMPK. Further docking and MD simulations of these compounds, inside VarTMPK and HssTMPK, suggest that nine among ten are potential selective inhibitors of VarTMPK. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  6. An Aminopyridazine Inhibitor of Death Associated Protein Kinase Attenuates Hypoxia-Ischemia Induced Brain Damage

    Energy Technology Data Exchange (ETDEWEB)

    Velentza, A.V.; Wainwright, M.S.; Zasadzki, M.; Mirzoeva, S.; Haiech, J.; Focia, P.J.; Egli, M.; Watterson, D.M.

    2010-03-08

    Death associated protein kinase (DAPK) is a calcium and calmodulin regulated enzyme that functions early in eukaryotic programmed cell death, or apoptosis. To validate DAPK as a potential drug discovery target for acute brain injury, the first small molecule DAPK inhibitor was synthesized and tested in vivo. A single injection of the aminopyridazine-based inhibitor administered 6 h after injury attenuated brain tissue or neuronal biomarker loss measured, respectively, 1 week and 3 days later. Because aminopyridazine is a privileged structure in neuropharmacology, we determined the high-resolution crystal structure of a binary complex between the kinase domain and a molecular fragment of the DAPK inhibitor. The co-crystal structure describes a structural basis for interaction and provides a firm foundation for structure-assisted design of lead compounds with appropriate molecular properties for future drug development.

  7. Inhibitor chymotrypsynowy nasion wiechliny łąkowej (Poa pratensis [Chymotrypsin inhibitor from Poa pratensis seeds

    Directory of Open Access Journals (Sweden)

    I. Lorenc-Kubis

    2015-01-01

    Full Text Available A chymotrypsin inhibitor was isolated from Poa pratensis seeds. The inhibitor showed also antytriptic activity. It is a termostable protein, soluble in water, sodium chloride, but insoluble in 5% trichloracetic acid and 0.15 M sulphosalicylic acid.

  8. Weak interactions

    International Nuclear Information System (INIS)

    Ogava, S.; Savada, S.; Nakagava, M.

    1983-01-01

    The problem of the use of weak interaction laws to study models of elementary particles is discussed. The most typical examples of weak interaction is beta-decay of nucleons and muons. Beta-interaction is presented by quark currents in the form of universal interaction of the V-A type. Universality of weak interactions is well confirmed using as examples e- and μ-channels of pion decay. Hypothesis on partial preservation of axial current is applicable to the analysis of processes with pion participation. In the framework of the model with four flavours lepton decays of hadrons are considered. Weak interaction without lepton participation are also considered. Properties of neutral currents are described briefly

  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. Floor interaction

    DEFF Research Database (Denmark)

    Petersen, Marianne Graves; Krogh, Peter; Ludvigsen, Martin

    2005-01-01

    Within architecture, there is a long tradition of careful design of floors. The design has been concerned with both decorating floors and designing floors to carry information. Ubiquitous computing technology offers new opportunities for designing interactive floors. This paper presents three...... different interactive floor concepts. Through an urban perspective it draws upon the experiences of floors in architecture, and provides a set of design issues for designing interactive floors....

  11. Phenyl- and benzylurea cytokinins as competitive inhibitors of cytokinin oxidase/dehydrogenase: a structural study.

    Science.gov (United States)

    Kopecný, David; Briozzo, Pierre; Popelková, Hana; Sebela, Marek; Koncitíková, Radka; Spíchal, Lukás; Nisler, Jaroslav; Madzak, Catherine; Frébort, Ivo; Laloue, Michel; Houba-Hérin, Nicole

    2010-08-01

    Cytokinin oxidase/dehydrogenase (CKO) is a flavoenzyme, which irreversibly degrades the plant hormones cytokinins and thereby participates in their homeostasis. Several synthetic cytokinins including urea derivatives are known CKO inhibitors but structural data explaining enzyme-inhibitor interactions are lacking. Thus, an inhibitory study with numerous urea derivatives was undertaken using the maize enzyme (ZmCKO1) and the crystal structure of ZmCKO1 in a complex with N-(2-chloro-pyridin-4-yl)-N'-phenylurea (CPPU) was solved. CPPU binds in a planar conformation and competes for the same binding site with natural substrates like N(6)-(2-isopentenyl)adenine (iP) and zeatin (Z). Nitrogens at the urea backbone are hydrogen bonded to the putative active site base Asp169. Subsequently, site-directed mutagenesis of L492 and E381 residues involved in the inhibitor binding was performed. The crystal structures of L492A mutant in a complex with CPPU and N-(2-chloro-pyridin-4-yl)-N'-benzylurea (CPBU) were solved and confirm the importance of a stacking interaction between the 2-chloro-4-pyridinyl ring of the inhibitor and the isoalloxazine ring of the FAD cofactor. Amino derivatives like N-(2-amino-pyridin-4-yl)-N'-phenylurea (APPU) inhibited ZmCKO1 more efficiently than CPPU, as opposed to the inhibition of E381A/S mutants, emphasizing the importance of this residue for inhibitor binding. As highly specific CKO inhibitors without undesired side effects are of major interest for physiological studies, all studied compounds were further analyzed for cytokinin activity in the Amaranthus bioassay and for binding to the Arabidopsis cytokinin receptors AHK3 and AHK4. By contrast to CPPU itself, APPU and several benzylureas bind only negligibly to the receptors and exhibit weak cytokinin activity. Copyright 2010 Elsevier Masson SAS. All rights reserved.

  12. SGLT2 inhibitors: are they safe?

    Science.gov (United States)

    Filippas-Ntekouan, Sebastian; Filippatos, Theodosios D; Elisaf, Moses S

    2018-01-01

    Sodium-glucose linked transporter type 2 (SGLT2) inhibitors are a relatively new class of antidiabetic drugs with positive cardiovascular and kidney effects. The aim of this review is to present the safety issues associated with SGLT2 inhibitors. Urogenital infections are the most frequently encountered adverse events, although tend to be mild to moderate and are easily manageable with standard treatment. Although no increased acute kidney injury risk was evident in the major trials, the mechanism of action of these drugs requires caution when they are administered in patients with extracellular volume depletion or with drugs affecting renal hemodynamics. Canagliflozin raised the risk of amputations and the rate of fractures in the CANVAS trial, although more data are necessary before drawing definite conclusions. The risk of euglycemic diabetic ketoacidosis seems to be minimal when the drugs are prescribed properly. Regarding other adverse events, SGLT2 inhibitors do not increase the risk of hypoglycemia even when co-administered with insulin, but a decrease in the dose of sulphonylureas may be needed. The available data do not point to a causative role of SGLT2 inhibitors on malignancy risk, however, these drugs should be used with caution in patients with known hematuria or history of bladder cancer. SGLT2 inhibitors seem to be safe and effective in the treatment of diabetes but more studies are required to assess their long-term safety.

  13. Aromatase inhibitors and breast cancer prevention.

    Science.gov (United States)

    Litton, Jennifer Keating; Arun, Banu K; Brown, Powel H; Hortobagyi, Gabriel N

    2012-02-01

    Endocrine therapy with selective estrogen receptor modulators (SERMs) has been the mainstay of breast cancer prevention trials to date. The aromatase inhibitors, which inhibit the final chemical conversion of androgens to estrogens, have shown increased disease-free survival benefit over tamoxifen in patients with primary hormone receptor-positive breast cancer, as well as reducing the risk of developing contralateral breast cancers. The aromatase inhibitors are being actively evaluated as prevention agents for women with a history of ductal carcinoma in situ as well as for women who are considered to be at high risk for developing primary invasive breast cancer. This review evaluates the available prevention data, as evidenced by the decrease in contralateral breast cancers, when aromatase inhibitors are used in the adjuvant setting, as well as the emerging data of the aromatase inhibitors specifically tested in the prevention setting for women at high risk. Exemestane is a viable option for breast cancer prevention. We continue to await further follow-up on exemestane as well as other aromatase inhibitors in the prevention setting for women at high risk of developing breast cancer or with a history of ductal carcinoma in situ.

  14. Janus kinase inhibitors: jackpot or potluck?

    Directory of Open Access Journals (Sweden)

    Pavithran Keechilat

    2012-06-01

    Full Text Available The reports of a unique mutation in the Janus kinase-2 gene (JAK2 in polycythemia vera by several independent groups in 2005 quickly spurred the development of the Janus kinase inhibitors. In one of the great victories of translational research in recent times, the first smallmolecule Janus kinase inhibitor ruxolitinib entered a phase I trial in 2007. With the approval of ruxolitinib by the US Federal Drug Administration in November 2011 for high-risk and intermediate-2 risk myelofibrosis, a change in paradigm has occurred in the management of a subset of myeloproliferative neoplasms (MPN: primary myelofibrosis, post-polycythemia vera myelofibrosis, and post-essential thrombocythemia myelofibrosis. Whereas the current evidence for ruxolitinib only covers high-risk and intermediate-2 risk myelofibrosis, inhibitors with greater potency are likely to offer better disease control and survival advantage in patients belonging to these categories, and possibly to the low-risk and intermediate-1 risk categories of MPN as well. But use of the Janus kinase inhibitors also probably has certain disadvantages, such as toxicity, resistance, withdrawal phenomenon, non-reversal of histology, and an implausible goal of disease clone eradication, some of which could offset the gains. In spite of this, Janus kinase inhibitors are here to stay, and for use in more than just myeloproliferative neoplasms.

  15. Playful Interaction

    DEFF Research Database (Denmark)

    2003-01-01

    The video Playful Interaction describes a future architectural office, and envisions ideas and concepts for playful interactions between people, materials and appliances in a pervasive and augmented working environment. The video both describes existing developments, technologies and designs...... as well as ideas not yet implemented such as playful modes of interaction with an augmented ball. Playful Interaction has been used as a hybrid of a vision video and a video prototype (1). Externally the video has been used to visualising our new ideas, and internally the video has also worked to inspire...

  16. Drugs against avian influenza a virus: design of novel sulfonate inhibitors of neuraminidase N1.

    Science.gov (United States)

    Udommaneethanakit, Thanyarat; Rungrotmongkol, Thanyada; Frecer, Vladimir; Seneci, Pierfausto; Miertus, Stanislav; Bren, Urban

    2014-01-01

    The outbreak of avian influenza A (H5N1) virus has raised a global concern for both the animal as well as human health. Besides vaccination, that may not achieve full protection in certain groups of patients, inhibiting neuraminidase or the transmembrane protein M2 represents the main measure of controlling the disease. Due to alarming emergence of influenza virus strains resistant to the currently available drugs, development of new neuraminidase N1 inhibitors is of utmost importance. The present paper provides an overview of the recent advances in the design of new antiviral drugs against avian influenza. It also reports findings in binding free energy calculations for nine neuraminidase N1 inhibitors (oseltamivir, zanamivir, and peramivir -carboxylate, -phosphonate, and -sulfonate) using the Linear Interaction Energy method. Molecular dynamics simulations of these inhibitors were performed in a free and two bound states - the so called open and closed conformations of neuraminidase N1. Obtained results successfully reproduce the experimental binding affinities of the already known neuraminidase N1 inhibitors, i.e. peramivir being a stronger binder than zanamivir that is in turn stronger binder than oseltamivir, or phosphonate inhibitors being stronger binders than their carboxylate analogues. In addition, the newly proposed sulfonate inhibitors are predicted to be the strongest binders - a fact to be confirmed by their chemical synthesis and a subsequent test of their biological activity. Finally, contributions of individual inhibitor moieties to the overall binding affinity are explicitly evaluated to assist further drug development towards inhibition of the H5N1 avian influenza A virus.

  17. Reversal of sodium pump inhibitor induced vascular smooth muscle contraction with digibind. Stoichiometry and its implications.

    Science.gov (United States)

    Krep, H H; Graves, S W; Price, D A; Lazarus, M; Ensign, A; Soszynski, P A; Hollenberg, N K

    1996-01-01

    The possibility that a circulating sodium pump inhibitor contributes to the pathogenesis of volume-dependent hypertension via an action on vascular smooth muscle (VSM) is supported by multiple lines of investigation, but remains controversial. We had two goals in this study. The first was to compare the pattern of contractile response of rabbit aorta induced by two candidates, ouabain and a labile sodium pump inhibitor that we have identified in the peritoneal dialysate of volume-expanded hypertensive patients with chronic renal failure. Our second goal was to examine the ability of Digibind, a Fab fragment of antisera directed against digoxin, to reverse VSM contraction induced by both agents. Ouabain induced a concentration-dependent contraction, which was delayed in onset, was gradual, and reached a stable plateau after many hours. The labile sodium pump inhibitor induced a qualitatively similar series of responses. Digibind rapidly reversed the contractile responses to both sodium pump inhibitors, with a rate of relaxation that matched that induced by physical removal of the pump inhibitor from the bath. For ouabain, the Digibind:ouabain stoichiometry was highly predictable. When Digibind was present in a molar concentration equivalent to that of ouabain, or less, it had no effect. When the Digibind concentration was twice that of ouabain, complete relaxation occurred. Although the concentration:VSM response relationship for ouabain was steep, the concentration:effect interaction with Digibind was even more steep. The molar concentration of Digibind required to reverse the effects of the labile endogenous inhibitor from peritoneal dialysate was consistently lower than that for ouabain, which is compatible with either greater potency of the labile factor in VSM or greater affinity for Digibind. These findings are compatible with a role for one or more endogenous sodium pump inhibitors as the determinant of vascular smooth muscle tone in the volume

  18. Contribution of murine innate serum inhibitors toward interference within influenza virus immune assays.

    Science.gov (United States)

    Cwach, Kevin T; Sandbulte, Heather R; Klonoski, Joshua M; Huber, Victor C

    2012-03-01

    Prior to detection of an antibody response toward influenza viruses using the hemagglutination inhibition assay (HAI), sera are routinely treated to inactivate innate inhibitors using both heat inactivation (56°C) and recombinant neuraminidase [receptor-destroying enzyme (RDE)]. We revisited the contributions of innate serum inhibitors toward interference with influenza viruses in immune assays, using murine sera, with emphasis on the interactions with influenza A viruses of the H3N2 subtype. We used individual serum treatments: 56°C alone, RDE alone, or RDE + 56°C, to treat sera prior to evaluation within HAI, microneutralization, and macrophage uptake assays. Our data demonstrate that inhibitors present within untreated murine sera interfere with the HAI assay in a manner that is different from that seen for the microneutralization assay. Specifically, the γ class inhibitor α(2) -Macroglobulin (A2-M) can inhibit H3N2 viruses within the HAI assay, but not in the microneutralization assay. Based on these findings, we used a macrophage uptake assay to demonstrate that these inhibitors can increase uptake by macrophages when the influenza viruses express an HA from a 1968 H3N2 virus isolate, but not a 1997 H3N2 isolate. The practice of treating sera to inactivate innate inhibitors of influenza viruses prior to evaluation within immune assays has allowed us to effectively detect influenza virus-specific antibodies for decades. However, this practice has yielded an under-appreciation for the contribution of innate serum inhibitors toward host immune responses against these viruses, including contributions toward neutralization and macrophage uptake. © 2011 Blackwell Publishing Ltd.

  19. Density functional theory (DFT) as a powerful tool for designing new organic corrosion inhibitors. Part 1: An overview

    International Nuclear Information System (INIS)

    Obot, I.B.; Macdonald, D.D.; Gasem, Z.M.

    2015-01-01

    The use of computational chemistry as a tool in the design and development of organic corrosion inhibitors has been greatly enhanced by the development of density functional theory (DFT). Whereas, traditionally, corrosion scientists have identified new corrosion inhibitor molecules either by incrementally changing the structures of existing inhibitors or by testing hundreds of compounds in the laboratory, these experimental means are often very expensive and time-consuming. Thus, ongoing hardware and software advances have opened the door for powerful use of theoretical chemistry in corrosion inhibition research at a reduced cost. DFT has enabled corrosion scientist to accurately predict the inhibition efficacies of organic corrosion inhibitors based on electronic/molecular properties and reactivity indices. This review summarizes the main features of DFT, giving a brief background to selected DFT-based chemical reactivity concepts, calculations and their applications to organic corrosion inhibitor design. The paper also reviews the principles upon which modern corrosion science is based with emphasis on corrosion in the oil and gas industry and with the goal of identifying important issues in the design of new, more effective inhibitors in this field. The impact of this review is to illustrate the enormous power of DFT and to identify shortcomings in past work, including the assumption that inhibitors only interact with bare metal surfaces.

  20. Research of small quaternary AChE inhibitors as pretreatment of OP poisoning

    International Nuclear Information System (INIS)

    Musilek, K.; Komloova, M.; Holas, O.; Opletalova, V.; Pohanka, M.; Kuca, K.

    2009-01-01

    Small quaternary AChE inhibitors are used (e.g. pyridostigmine) or scoped (e.g. SAD-128) for pretreatment against organophosphate intoxication [1]. The pretreatment is based on competitive inhibition of AChE prior to organophosphate (OP) poisoning. Consequently, the OP can not influence the inhibited AChE and is degraded by other esterases. Although various competitive inhibitors are used globally, pyridostigmine still remains the most broaden. Its side effects including gastrointestinal effects (nausea, intestinal obstruction), increased bronchial secretion, cardiac arrhythmia or cholinergic crisis are well described. Moreover, some bisquaternary competitive inhibitors (e.g. SAD-128) were used to decrease lethal effects of OP poisoning in vivo. The further studies dealing with SAD-128 showed its increased ability to interact with brain muscarinic acetylcholine receptors as allosteric inhibitors [2]. The small molecules derived from quaternized pyridine, quinoline and isoquinoline were designed as AChE inhibitors. Their ability to inhibit AChE or BChE was determined in vitro using IC50. The IC50 data were compared within each group of compounds with emphasis on selectivity AChE versus BChE. The overall study will be presented. The work was supported by Ministry of Defence of Czech Republic No. OVUOFVZ200805.(author)

  1. Inflammatory Signaling by NOD-RIPK2 Is Inhibited by Clinically Relevant Type II Kinase Inhibitors.

    Science.gov (United States)

    Canning, Peter; Ruan, Qui; Schwerd, Tobias; Hrdinka, Matous; Maki, Jenny L; Saleh, Danish; Suebsuwong, Chalada; Ray, Soumya; Brennan, Paul E; Cuny, Gregory D; Uhlig, Holm H; Gyrd-Hansen, Mads; Degterev, Alexei; Bullock, Alex N

    2015-09-17

    RIPK2 mediates pro-inflammatory signaling from the bacterial sensors NOD1 and NOD2, and is an emerging therapeutic target in autoimmune and inflammatory diseases. We observed that cellular RIPK2 can be potently inhibited by type II inhibitors that displace the kinase activation segment, whereas ATP-competitive type I inhibition was only poorly effective. The most potent RIPK2 inhibitors were the US Food and Drug Administration-approved drugs ponatinib and regorafenib. Their mechanism of action was independent of NOD2 interaction and involved loss of downstream kinase activation as evidenced by lack of RIPK2 autophosphorylation. Notably, these molecules also blocked RIPK2 ubiquitination and, consequently, inflammatory nuclear factor κB signaling. In monocytes, the inhibitors selectively blocked NOD-dependent tumor necrosis factor production without affecting lipopolysaccharide-dependent pathways. We also determined the first crystal structure of RIPK2 bound to ponatinib, and identified an allosteric site for inhibitor development. These results highlight the potential for type II inhibitors to treat indications of RIPK2 activation as well as inflammation-associated cancers. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. Effects of SGLT2 inhibitors on weight loss in patients with type 2 diabetes mellitus.

    Science.gov (United States)

    Ribola, F A; Cançado, F B; Schoueri, J H M; De Toni, V F; Medeiros, V H R; Feder, D

    2017-01-01

    SGLT2 (sodium-glucose cotransporter type 2) inhibitors are a new class of drugs which reversibly block the glucose reabsorption that occurs in the kidneys. Since their mechanisms of action do not rely on insulin secretion, they constitute a complementary alternative to the classic treatment of type 2 diabetes mellitus. A glycemic level reduction in patients who used SGLT2 inhibitors due to the reversible block of their transporters could be observed. Associated with this, there was a reduction in body weight and blood pressure (BP) caused by osmotic diuresis. Few adverse effects and low drug interaction combined with antihyperglycemic effects are some of the benefits of these inhibitors widely discussed in clinical trials. Patients with history of urogenital infections or those on diuretics must be carefully evaluated before the administration of these drugs. While a promising class of drugs indicated as a treatment for patients with type 2 diabetes mellitus, SGLT2 inhibitors should not be prescribed for individuals with severe renal or hepatic impairment. Therefore, as there are only a few situations in which they should not be indicated, the efficacy, safety and tolerability of these inhibitors allow them to be used in a wide range of patients. Nevertheless, further researches are required so that the possible long-term risks can be studied and the benefits associated with their use can be more objectively elucidated.

  3. Synthesis, cytotoxicity and molecular modelling studies of new phenylcinnamide derivatives as potent inhibitors of cholinesterases.

    Science.gov (United States)

    Saeed, Aamer; Mahesar, Parvez Ali; Zaib, Sumera; Khan, Muhammad Siraj; Matin, Abdul; Shahid, Mohammad; Iqbal, Jamshed

    2014-05-06

    The present study reports the synthesis of cinnamide derivatives and their biological activity as inhibitors of both cholinesterases and anticancer agents. Controlled inhibition of brain acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) may slow neurodegeneration in Alzheimer's diseases (AD). The anticholinesterase activity of phenylcinnamide derivatives was determined against Electric Eel acetylcholinesterase (EeAChE) and horse serum butyrylcholinesterase (hBChE) and some of the compounds appeared as moderately potent inhibitors of EeAChE and hBChE. The compound 3-(2-(Benzyloxy)phenyl)-N-(3,4,5-trimethoxyphenyl)acrylamide (3i) showed maximum activity against EeAChE with an IC50 0.29 ± 0.21 μM whereas 3-(2-chloro-6-nitrophenyl)-N-(3,4,5-trimethoxyphenyl)acrylamide (3k) was proved to be the most potent inhibitor of hBChE having IC50 1.18 ± 1.31 μM. To better understand the enzyme-inhibitor interaction of the most active compounds toward cholinesterases, molecular modelling studies were carried out on high-resolution crystallographic structures. The anticancer effects of synthesized compounds were also evaluated against cancer cell line (lung carcinoma). The compounds may be useful leads for the design of a new class of anticancer drugs for the treatment of cancer and cholinesterase inhibitors for Alzheimer's disease (AD). Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  4. Synthesis, pharmacological evaluation and molecular docking studies of pyrimidinedione based DPP-4 inhibitors as antidiabetic agents

    Science.gov (United States)

    Jha, Vibhu; Bhadoriya, Kamlendra Singh

    2018-04-01

    Dipeptidyl peptidase-4 (DPP-4) inhibitors are a class of newly developed antidiabetic drugs that bock DPP-4. DPP-4 is responsible for degradation of incretins harmones such as GLP-1 (Glucagon like Peptide) and GIP (Gastric inhibitory polypeptide) that maintain blood-glucose level. Pyrimidinedione based compounds were designed and synthesized for DPP-4 inhibitory activity. These heterocycles were designed by taking Alogliptin as a reference DPP-4 inhibitors and synthesized as N-methylated and N-benzylated pyrimidinediones. These compounds were subjected to DPP-4 assay, five out of nine synthesized compounds have shown in vitro DPP-4 inhibitory activity in significant range. Further, molecular docking studies of these compounds were performed on DPP-4 subunit and compared with natural DPP-4 inhibitors like Flavone, Resveratrol, Quercetin, Diprotin A. Docking studies have led to the conclusion that there are some identical amino acid interactions as Tyr 666 and Tyr 662, seen in both synthesized compounds and natural DPP-4 inhibitors. This study completely gives a good scope for further derivatisation and optimization of synthesized compounds to get clinical candidate as DPP-4 inhibitor for antidiabetic activity.

  5. Comparative Amino Acid Decomposition Analysis of Potent Type I P38α Inhibitors

    Directory of Open Access Journals (Sweden)

    Ahmad Ebadi

    2013-05-01

    Full Text Available Background and purpose of the study:p38α is a member of mitogen-activated protein kinases (MAPK considered as a prominent target in development of anti-inflammatory agents. Any abnormality in the phosphorylation process leads to the different human diseases such as cancer, diabetes and inflammatory diseases. Several small molecule p38α inhibitors have been developed up to now. In this regard, structural elucidation of p38 inhibitors needs to be done enabling us in rational lead development strategies.Methods:Various interactions of three potent inhibitors with p38α active site have been evaluated in terms of binding energies and bond lengths via density function theory and MD simulations.Results:Our comparative study showed that both ab initio and MD simulation led to the relatively similar results in pharmacophore discrimination of p38α inhibitors.Conclusion:The results of the present study may find their usefulness in pharmacophore based modification of p38α inhibitors.

  6. Promiscuity and selectivity of small-molecule inhibitors across TAM receptor tyrosine kinases in pediatric leukemia.

    Science.gov (United States)

    Liu, Mao-Hua; Chen, Shi-Bing; Yu, Juan; Liu, Cheng-Jun; Zhang, Xiao-Jing

    2017-08-01

    The TAM receptor tyrosine kinase family member Mer has been recognized as an attractive therapeutic target for pediatric leukemia. Beside Mer the family contains other two kinases, namely, Tyro3 and Axl, which are highly homologues with Mer and thus most existing small-molecule inhibitors show moderate or high promiscuity across the three kinases. Here, the structural basis and energetic property of selective binding of small-molecule inhibitors to the three kinases were investigated at molecular level. It is found that the selectivity is primarily determined by the size, shape and configuration of kinase's ATP-binding site; the Mer and Axl possess a small, closed active pocket as compared to the bulky, open pocket of Tyro3. The location and conformation of active-site residues of Mer and Axl are highly consistent, suggesting that small-molecule inhibitors generally have a low Mer-over-Axl selectivity and a high Mer-over-Tyro3 selectivity. We demonstrated that the difference in ATP binding potency to the three kinases is also responsible for inhibitor selectivity. We also found that the long-range interactions and allosteric effect arising from rest of the kinase's active site can indirectly influence inhibitor binding and selectivity. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Discovery and optimization of antibacterial AccC inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Cliff C.; Shipps, Jr., Gerald W.; Yang, Zhiwei; Sun, Binyuan; Kawahata, Noriyuki; Soucy, Kyle A.; Soriano, Aileen; Orth, Peter; Xiao, Li; Mann, Paul; Black, Todd; (SPRI)

    2010-09-17

    The biotin carboxylase (AccC) is part of the multi-component bacterial acetyl coenzyme-A carboxylase (ACCase) and is essential for pathogen survival. We describe herein the affinity optimization of an initial hit to give 2-(2-chlorobenzylamino)-1-(cyclohexylmethyl)-1H-benzo[d]imidazole-5-carboxamide (1), which was identified using our proprietary Automated Ligand Identification System (ALIS). The X-ray co-crystal structure of 1 was solved and revealed several key interactions and opportunities for further optimization in the ATP site of AccC. Structure Based Drug Design (SBDD) and parallel synthetic approaches resulted in a novel series of AccC inhibitors, exemplified by (R)-2-(2-chlorobenzylamino)-1-(2,3-dihydro-1H-inden-1-yl)-1H-imidazo[4,5-b]pyridine-5-carboxamide (40). This compound is a potent and selective inhibitor of bacterial AccC with an IC{sub 50} of 20 nM and a MIC of 0.8 {micro}g/mL against a sensitized strain of Escherichia coli (HS294 E. coli).

  8. Peptide-based proteasome inhibitors in anticancer drug design.

    Science.gov (United States)

    Micale, Nicola; Scarbaci, Kety; Troiano, Valeria; Ettari, Roberta; Grasso, Silvana; Zappalà, Maria

    2014-09-01

    The identification of the key role of the eukaryotic 26S proteasome in regulated intracellular proteolysis and its importance as a target in many pathological conditions wherein the proteasomal activity is defective (e.g., malignancies, autoimmune diseases, neurodegenerative diseases, etc.) prompted several research groups to the development of specific inhibitors of this multicatalytic complex with the aim of obtaining valid drug candidates. In regard to the anticancer therapy, the peptide boronate bortezomib (Velcade®) represents the first molecule approved by FDA for the treatment of multiple myeloma in 2003 and mantle cell lymphoma in 2006. Since then, a plethora of molecules targeting the proteasome have been identified as potential anticancer agents and a few of them reached clinical trials or are already in the market (i.e., carfilzomib; Kyprolis®). In most cases, the design of new proteasome inhibitors (PIs) takes into account a proven peptide or pseudopeptide motif as a base structure and places other chemical entities throughout the peptide skeleton in such a way to create an efficacious network of interactions within the catalytic sites. The purpose of this review is to provide an in-depth look at the current state of the research in the field of peptide-based PIs, specifically those ones that might find an application as anticancer agents. © 2014 Wiley Periodicals, Inc.

  9. Nitrite and nitroso compounds can serve as specific catalase inhibitors.

    Science.gov (United States)

    Titov, Vladimir Yu; Osipov, Anatoly N

    2017-03-01

    We present evidence that nitrite and nitrosothiols, nitrosoamines and non-heme dinitrosyl iron complexes can reversibly inhibit catalase with equal effectiveness. Catalase activity was evaluated by the permanganatometric and calorimetric assays. This inhibition is not the result of chemical transformations of these compounds to a single inhibitor, as well as it is not the result of NO release from these substances (as NO traps have no effect on the extent of inhibition). It was found that chloride and bromide in concentration above 80 mM and thiocyanate in concentration above 20 μM enhance catalase inhibition by nitrite and the nitroso compounds more than 100 times. The inhibition degree in this case is comparable with that induced by azide. We propose that the direct catalase inhibitor is a positively charged NO-group. This group acquires a positive charge in the active center of enzyme by interaction of nitrite or nitroso compounds with some enzyme groups. Halides and thiocyanate protect the NO + group from hydration and thus increase its inhibition effect. It is probable that a comparatively low chloride concentration in many cells is the main factor to protect catalase from inhibition by nitrite and nitroso compounds.

  10. MEROPS: the database of proteolytic enzymes, their substrates and inhibitors.

    Science.gov (United States)

    Rawlings, Neil D; Waller, Matthew; Barrett, Alan J; Bateman, Alex

    2014-01-01

    Peptidases, their substrates and inhibitors are of great relevance to biology, medicine and biotechnology. The MEROPS database (http://merops.sanger.ac.uk) aims to fulfill the need for an integrated source of information about these. The database has hierarchical classifications in which homologous sets of peptidases and protein inhibitors are grouped into protein species, which are grouped into families, which are in turn grouped into clans. Recent developments include the following. A community annotation project has been instigated in which acknowledged experts are invited to contribute summaries for peptidases. Software has been written to provide an Internet-based data entry form. Contributors are acknowledged on the relevant web page. A new display showing the intron/exon structures of eukaryote peptidase genes and the phasing of the junctions has been implemented. It is now possible to filter the list of peptidases from a completely sequenced bacterial genome for a particular strain of the organism. The MEROPS filing pipeline has been altered to circumvent the restrictions imposed on non-interactive blastp searches, and a HMMER search using specially generated alignments to maximize the distribution of organisms returned in the search results has been added.

  11. Intrinsic thermodynamics of inhibitor binding to human carbonic anhydrase IX.

    Science.gov (United States)

    Linkuvienė, Vaida; Matulienė, Jurgita; Juozapaitienė, Vaida; Michailovienė, Vilma; Jachno, Jelena; Matulis, Daumantas

    2016-04-01

    Human carbonic anhydrase 9th isoform (CA IX) is an important marker of numerous cancers and is increasingly interesting as a potential anticancer drug target. Various synthetic aromatic sulfonamide-bearing compounds are being designed as potent inhibitors of CA IX. However, sulfonamide compound binding to CA IX is linked to several reactions, the deprotonation of the sulfonamide amino group and the protonation of the CA active site Zn(II)-bound hydroxide. These linked reactions significantly affect the affinities and other thermodynamic parameters such as enthalpies and entropies of binding. The observed and intrinsic affinities of compound binding to CA IX were determined by the fluorescent thermal shift assay. The enthalpies and entropies of binding were determined by the isothermal titration calorimetry. The pKa of CA IX was determined to be 6.8 and the enthalpy of CA IX-Zn(II)-bound hydroxide protonation was -24 kJ/mol. These values enabled the analysis of intrinsic thermodynamics of a library of compounds binding to CA IX. The most strongly binding compounds exhibited the intrinsic affinity of 0.01 nM and the observed affinity of 2 nM. The intrinsic thermodynamic parameters of compound binding to CA IX helped to draw the compound structure to thermodynamics relationship. It is important to distinguish the intrinsic from observed parameters of any disease target protein interaction with its inhibitors as drug candidates when drawing detailed compound structure to thermodynamics correlations. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. SGLT-2 Inhibitors and Cardiovascular Risk

    DEFF Research Database (Denmark)

    Cavender, Matthew A; Norhammar, Anna; Birkeland, Kåre I

    2018-01-01

    BACKGROUND: Prior studies found patients treated with sodium-glucose co-transporter-2 inhibitors (SGLT-2i) had lower rates of death and heart failure (HF). Whether the benefits of SGLT-2i vary based upon the presence of cardiovascular disease (CVD) is unknown. OBJECTIVES: This study sought...... to determine the association between initiation of SGLT-2i therapy and HF or death in patients with and without CVD. METHODS: The CVD-REAL (Comparative Effectiveness of Cardiovascular Outcomes in New Users of SGLT-2 Inhibitors) study was a multinational, observational study in which adults with type 2 diabetes...... evidence regarding the benefit of SGLT-2i in patients without established CVD. (Comparative Effectiveness of Cardiovascular Outcomes in New Users of SGLT-2 Inhibitors [CVD-REAL]; NCT02993614)....

  13. Discovery of potent inhibitors of soluble epoxide hydrolase by combinatorial library design and structure-based virtual screening.

    Science.gov (United States)

    Xing, Li; McDonald, Joseph J; Kolodziej, Steve A; Kurumbail, Ravi G; Williams, Jennifer M; Warren, Chad J; O'Neal, Janet M; Skepner, Jill E; Roberds, Steven L

    2011-03-10

    Structure-based virtual screening was applied to design combinatorial libraries to discover novel and potent soluble epoxide hydrolase (sEH) inhibitors. X-ray crystal structures revealed unique interactions for a benzoxazole template in addition to the conserved hydrogen bonds with the catalytic machinery of sEH. By exploitation of the favorable binding elements, two iterations of library design based on amide coupling were employed, guided principally by the docking results of the enumerated virtual products. Biological screening of the libraries demonstrated as high as 90% hit rate, of which over two dozen compounds were single digit nanomolar sEH inhibitors by IC(50) determination. In total the library design and synthesis produced more than 300 submicromolar sEH inhibitors. In cellular systems consistent activities were demonstrated with biochemical measurements. The SAR understanding of the benzoxazole template provides valuable insights into discovery of novel sEH inhibitors as therapeutic agents.

  14. Covalent cross-linking of insulin-like growth factor-1 to a specific inhibitor from human serum

    International Nuclear Information System (INIS)

    Ooi, G.T.; Herington, A.C.

    1986-01-01

    Previous studies have shown that a specific inhibitor of insulin-like growth factor (IGF) action in vitro can be isolated from normal human serum and subsequently partially purified on an IGF-affinity column. The ability of the inhibitor to bind the IGFs has now been confirmed directly using covalent cross-linking techniques. When 125 I-IGF-1 was cross-linked to inhibitor using disuccinimidyl suberate, five specifically labelled bands were seen on SDS-PAGE and autoradiography. Two bands (MW 21.5 K and 25.5 K) were intensely labelled, while the remaining three (MW 37 K, 34 K and 18 K) appeared as minor bands only. Inhibitor bioactivity, following further analysis by hydrophobic interaction chromatography or Con A-Sepharose affinity chromatography, was always associated with the presence of the 21.5 K and/or 25.5 K bands

  15. Aesthetic interaction

    DEFF Research Database (Denmark)

    Petersen, Marianne Graves; Iversen, Ole Sejer; Krogh, Peter

    2004-01-01

    , as it promotes aesthetics of use, rather than aesthetics of appearance. We coin this approach in the perspective of aesthetic interaction. Finally we make the point that aesthetics is not re-defining everything known about interactive systems. We provide a framework placing this perspective among other...

  16. Interactive benchmarking

    DEFF Research Database (Denmark)

    Lawson, Lartey; Nielsen, Kurt

    2005-01-01

    We discuss individual learning by interactive benchmarking using stochastic frontier models. The interactions allow the user to tailor the performance evaluation to preferences and explore alternative improvement strategies by selecting and searching the different frontiers using directional...... in the suggested benchmarking tool. The study investigates how different characteristics on dairy farms influences the technical efficiency....

  17. Explicit Interaction

    DEFF Research Database (Denmark)

    Löwgren, Jonas; Eriksen, Mette Agger; Linde, Per

    2006-01-01

    We report an ongoing study of palpable computing to support surgical rehabilitation, in the general field of interaction design for ubiquitous computing. Through explorative design, fieldwork and participatory design techniques, we explore the design principle of explicit interaction as an interp...

  18. Kinesthetic Interaction

    DEFF Research Database (Denmark)

    Fogtmann, Maiken Hillerup; Fritsch, Jonas; Kortbek, Karen Johanne

    2008-01-01

    Within the Human-Computer Interaction community there is a growing interest in designing for the whole body in interaction design. The attempts aimed at addressing the body have very different outcomes spanning from theoretical arguments for understanding the body in the design process, to more...... practical examples of designing for bodily potential. This paper presents Kinesthetic Interaction as a unifying concept for describing the body in motion as a foundation for designing interactive systems. Based on the theoretical foundation for Kinesthetic Interaction, a conceptual framework is introduced...... to reveal bodily potential in relation to three design themes – kinesthetic development, kinesthetic means and kinesthetic disorder; and seven design parameters – engagement, sociality, movability, explicit motivation, implicit motivation, expressive meaning and kinesthetic empathy. The framework is a tool...

  19. Evaluating SGLT2 inhibitors for type 2 diabetes: pharmacokinetic and toxicological considerations.

    Science.gov (United States)

    Scheen, André J

    2014-05-01

    Inhibitors of sodium-glucose cotransporters type 2 (SGLT2), which increase urinary glucose excretion independently of insulin, are proposed as a novel approach for the management of type 2 diabetes mellitus (T2DM). An extensive literature search was performed to analyze the pharmacokinetic characteristics, toxicological issues and safety concerns of SGLT2 inhibitors in humans. This review focuses on three compounds (dapagliflozin, canagliflozin, empagliflozin) with results obtained in healthy volunteers (including drug-drug interactions), patients with T2DM (single dose and multiple doses) and special populations (those with renal or hepatic impairment). The three pharmacological agents share an excellent oral bioavailability, long half-life allowing once-daily administration, low accumulation index and renal clearance, the absence of active metabolites and a limited propensity to drug-drug interactions. No clinically relevant changes in pharmacokinetic parameters were observed in T2DM patients or in patients with mild/moderate renal or hepatic impairment. Adverse events are a slightly increased incidence of mycotic genital and rare benign urinary infections. SGLT2 inhibitors have the potential to reduce several cardiovascular risk factors, and cardiovascular outcome trials are currently ongoing. The best positioning of SGLT2 inhibitors in the armamentarium for treating T2DM is still a matter of debate.

  20. STRUCTURAL ASPECTS OF STRONG INHIBITION AND ROLE OF SCAFFOLD FOR SERINE PROTEASE INHIBITORS

    Directory of Open Access Journals (Sweden)

    Jhimli Dasgupta

    2011-12-01

    Full Text Available Canonical serine protease inhibitors inhibit their cognate enzymes by binding tightly at the enzyme active site in a substrate-like manner, being cleaved extremely slowly compared to a true substrate. They interact with cognate enzymes through P3-P2 region of the inhibitory loop while the scaffold hardly makes any contact. Neighbouring scaffolding residues like arginine or asparagine shape-up the inhibitory loop and religate the cleaved scissile bond. The specificity of the inhibitor can be altered by mutating the hyper solvent accessible P1 residue without changing loop-scaffold interactions. To understand the loop-scaffold compatibility, we prepared three chimeric proteins ECIL-WCIS , ETIL-WCIS , and STIL-WCIS , where the inhibitory loops of ECI, ETI, and STI were placed on the scaffold of their homologue WCI. Results showed that although ECIL-WCIS and STIL-WCIS behave like inhibitors, ETIL-WCIS behaves like a substrate. Crystal structure of ETIL-WCIS and its comparison with ETI indicated that three novel scaffolding residues Trp88, Arg74, and Tyr113 in ETI act as barrier to confine the inhibitory loop to canonical conformation. Absence of this barrier in the scaffold of WCI makes the inhibitory loop flexible in ETIL-WCIS leading to a loss of canonical conformation, explaining its substrate-like behaviour. Furthermore, complex structures of the inhibitors with their cognate enzymes indicate that rigidification of the inhibitory loop at the enzyme active site is necessary for efficient inhibition.

  1. 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.

  2. Green inhibitors. Rare Earth based systems

    International Nuclear Information System (INIS)

    Aballe, A.; Bethencourt, M.; Botana, F.J.; Perez, J.; Rodriguez, M.A.; Marcos, M.

    1997-01-01

    Lanthanum, Cerium and Samarium chlorides have been investigated as uniform and pitting corrosion inhibitors of AISI 434 and AISI 304 stainless steels and AA 5083 Al-Mg alloy in 3.5% Na Cl aerated aqueous solutions. Their inhibitor power was evaluated by using electrochemical techniques such as Linear and Cyclic Polarisation. In each case, the highest protection degree was found in the solution dropped with 500 ppm of CeCl 3 . Similar results were obtained for additions of 500 ppm of LaCl 3 . Scanning Electron Microscopy and Energy Dispersive Spectroscopy allowed us to confirm the cathodic nature of the inhibition process. (Author) 27 refs

  3. 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.

  4. The proton pump inhibitor, omeprazole, but not lansoprazole or pantoprazole, is a metabolism-dependent inhibitor of CYP2C19: implications for coadministration with clopidogrel.

    Science.gov (United States)

    Ogilvie, Brian W; Yerino, Phyllis; Kazmi, Faraz; Buckley, David B; Rostami-Hodjegan, Amin; Paris, Brandy L; Toren, Paul; Parkinson, Andrew

    2011-11-01

    As a direct-acting inhibitor of CYP2C19 in vitro, lansoprazole is more potent than omeprazole and other proton pump inhibitors (PPIs), but lansoprazole does not cause clinically significant inhibition of CYP2C19 whereas omeprazole does. To investigate this apparent paradox, we evaluated omeprazole, esomeprazole, R-omeprazole, lansoprazole, and pantoprazole for their ability to function as direct-acting and metabolism-dependent inhibitors (MDIs) of CYP2C19 in pooled human liver microsomes (HLM) as well as in cryopreserved hepatocytes and recombinant CYP2C19. In HLM, all PPIs were found to be direct-acting inhibitors of CYP2C19 with IC(50) values varying from 1.2 μM [lansoprazole; maximum plasma concentration (C(max)) = 2.2 μM] to 93 μM (pantoprazole; C(max) = 6.5 μM). In addition, we identified omeprazole, esomeprazole, R-omeprazole, and omeprazole sulfone as MDIs of CYP2C19 (they caused IC(50) shifts after a 30-min preincubation with NADPH-fortified HLM of 4.2-, 10-, 2.5-, and 3.2-fold, respectively), whereas lansoprazole and pantoprazole were not MDIs (IC(50) shifts lansoprazole, or pantoprazole, as irreversible (or quasi-irreversible) MDIs of CYP2C19. These results have important implications for the mechanism of the clinical interaction reported between omeprazole and clopidogrel, as well as other CYP2C19 substrates.

  5. Identification of Leishmania donovani Topoisomerase 1 inhibitors via intuitive scaffold hopping and bioisosteric modification of known Top 1 inhibitors

    Science.gov (United States)

    Mamidala, Rajinikanth; Majumdar, Papiya; Jha, Kunal Kumar; Bathula, Chandramohan; Agarwal, Rahul; Chary, M. Thirumala; Mazumdar, H. K.; Munshi, Parthapratim; Sen, Subhabrata

    2016-05-01

    A library of arylidenefuropyridinediones was discovered as potent inhibitors of Leishmania donovani Topoisomerase 1 (LdTop1) where the active molecules displayed considerable inhibition with single digit micromolar EC50 values. This molecular library was designed via intuitive scaffold hopping and bioisosteric modification of known topoisomerase 1 inhibitors such as camptothecin, edotecarin and etc. The design was rationalized by molecular docking analysis of the compound prototype with human topoisomerase 1 (HTop1) and Leishmania donovani topoisomerase 1(LdTop1). The most active compound 4 displayed no cytotoxicity against normal mammalian COS7 cell line (~100 fold less inhibition at the EC50). Similar to camptothecin, 4 interacted with free LdTop1 as observed in the preincubation DNA relaxation inhibition experiment. It also displayed anti-protozoal activity against Leishmania donovani promastigote. Crystal structure investigation of 4 and its molecular modelling with LdTop1 revealed putative binding sites in the enzyme that could be harnessed to generate molecules with better potency.

  6. Immunological changes with kinase inhibitor therapy for chronic lymphocytic leukemia.

    Science.gov (United States)

    Pleyer, Christopher; Wiestner, Adrian; Sun, Clare

    2018-05-15

    Ibrutinib and idelalisib are kinase inhibitors that have revolutionized the treatment of chronic lymphocytic leukemia (CLL). Capable of inducing durable remissions, these agents also modulate the immune system. Both ibrutinib and idelalisib abrogate the tumor-supporting microenvironment by disrupting cell-cell interactions, modulating the T-cell compartment, and altering the cytokine milieu. Ibrutinib also partially restores T-cell and myeloid defects associated with CLL. In contrast, immune-related adverse effects, including pneumonitis, colitis, hepatotoxicity, and infections are of particular concern with idelalisib. While opportunistic infections and viral reactivations occur with both ibrutinib and idelalisib, these complications are less common and less severe with ibrutinib, especially when used as monotherapy without additional immunosuppressive agents. This review discusses the impact of ibrutinib and idelalisib on the immune system, including infectious and auto-immune complications as well as their specific effects on the B-cell, T-cell, and myeloid compartment.

  7. Development of potent inhibitors of the coxsackievirus 3C protease

    International Nuclear Information System (INIS)

    Lee, Eui Seung; Lee, Won Gil; Yun, Soo-Hyeon; Rho, Seong Hwan; Im, Isak; Yang, Sung Tae; Sellamuthu, Saravanan; Lee, Yong Jae; Kwon, Sun Jae; Park, Ohkmae K.; Jeon, Eun-Seok; Park, Woo Jin; Kim, Yong-Chul

    2007-01-01

    Coxsackievirus B3 (CVB3) 3C protease (3CP) plays essential roles in the viral replication cycle, and therefore, provides an attractive therapeutic target for treatment of human diseases caused by CVB3 infection. CVB3 3CP and human rhinovirus (HRV) 3CP have a high degree of amino acid sequence similarity. Comparative modeling of these two 3CPs revealed one prominent distinction; an Asn residue delineating the S2' pocket in HRV 3CP is replaced by a Tyr residue in CVB3 3CP. AG7088, a potent inhibitor of HRV 3CP, was modified by substitution of the ethyl group at the P2' position with various hydrophobic aromatic rings that are predicted to interact preferentially with the Tyr residue in the S2' pocket of CVB3 3CP. The resulting derivatives showed dramatically increased inhibitory activities against CVB3 3CP. In addition, one of the derivatives effectively inhibited the CVB3 proliferation in vitro

  8. A new class of HIV-1 protease inhibitor: the crystallographic structure, inhibition and chemical synthesis of an aminimide peptide isostere.

    Science.gov (United States)

    Rutenber, E E; McPhee, F; Kaplan, A P; Gallion, S L; Hogan, J C; Craik, C S; Stroud, R M

    1996-09-01

    The essential role of HIV-1 protease (HIV-1 PR) in the viral life cycle makes it an attractive target for the development of substrate-based inhibitors that may find efficacy as anti-AIDS drugs. However, resistance has arisen to potent peptidomimetic drugs necessitating the further development of novel chemical backbones for diversity based chemistry focused on probing the active site for inhibitor interactions and binding modes that evade protease resistance. AQ148 is a potent inhibitor of HIV-1 PR and represents a new class of transition state analogues incorporating an aminimide peptide isostere. A 3-D crystallographic structure of AQ148, a tetrapeptide isostere, has been determined in complex with its target HIV-1 PR to a resolution of 2.5 A and used to evaluate the specific structural determinants of AQ148 potency and to correlate structure-activity relationships within the class of related compounds. AQ148 is a competitive inhibitor of HIV-1 PR with a Ki value of 137 nM. Twenty-nine derivatives have been synthesized and chemical modifications have been made at the P1, P2, P1', and P2' sites. The atomic resolution structure of AQ148 bound to HIV-1 PR reveals both an inhibitor binding mode that closely resembles that of other peptidomimetic inhibitors and specific protein/inhibitor interactions that correlate with structure-activity relationships. The structure provides the basis for the design, synthesis and evaluation of the next generation of hydroxyethyl aminimide inhibitors. The aminimide peptide isostere is a scaffold with favorable biological properties well suited to both the combinatorial methods of peptidomimesis and the rational design of potent and specific substrate-based analogues.

  9. 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.

  10. Herb-drug interactions.

    Science.gov (United States)

    Fugh-Berman, A

    2000-01-08

    Concurrent use of herbs may mimic, magnify, or oppose the effect of drugs. Plausible cases of herb-drug interactions include: bleeding when warfarin is combined with ginkgo (Ginkgo biloba), garlic (Allium sativum), dong quai (Angelica sinensis), or danshen (Salvia miltiorrhiza); mild serotonin syndrome in patients who mix St John's wort (Hypericum perforatum) with serotonin-reuptake inhibitors; decreased bioavailability of digoxin, theophylline, cyclosporin, and phenprocoumon when these drugs are combined with St John's wort; induction of mania in depressed patients who mix antidepressants and Panax ginseng; exacerbation of extrapyramidal effects with neuroleptic drugs and betel nut (Areca catechu); increased risk of hypertension when tricyclic antidepressants are combined with yohimbine (Pausinystalia yohimbe); potentiation of oral and topical corticosteroids by liquorice (Glycyrrhiza glabra); decreased blood concentrations of prednisolone when taken with the Chinese herbal product xaio chai hu tang (sho-salko-to); and decreased concentrations of phenytoin when combined with the Ayurvedic syrup shankhapushpi. Anthranoid-containing plants (including senna [Cassia senna] and cascara [Rhamnus purshiana]) and soluble fibres (including guar gum and psyllium) can decrease the absorption of drugs. Many reports of herb-drug interactions are sketchy and lack laboratory analysis of suspect preparations. Health-care practitioners should caution patients against mixing herbs and pharmaceutical drugs.

  11. 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

  12. Programming Interactivity

    CERN Document Server

    Noble, Joshua

    2012-01-01

    Ready to create rich interactive experiences with your artwork, designs, or prototypes? This is the ideal place to start. With this hands-on guide, you'll explore several themes in interactive art and design-including 3D graphics, sound, physical interaction, computer vision, and geolocation-and learn the basic programming and electronics concepts you need to implement them. No previous experience is necessary. You'll get a complete introduction to three free tools created specifically for artists and designers: the Processing programming language, the Arduino microcontroller, and the openFr

  13. Bisindolylmethane thiosemicarbazides as potential inhibitors of urease: Synthesis and molecular modeling studies.

    Science.gov (United States)

    Taha, Muhammad; Ullah, Hayat; Al Muqarrabun, Laode Muhammad Ramadhan; Khan, Muhammad Naseem; Rahim, Fazal; Ahmat, Norizan; Javid, Muhammad Tariq; Ali, Muhammad; Khan, Khalid Mohammed

    2018-01-01

    Bisindolylmethane thiosemicarbazides 1-18 were synthesized, characterized by 1 H NMR and ESI MS and evaluated for urease inhibitory potential. All analogs showed outstanding urease inhibitory potentials with IC 50 values ranging between 0.14 ± 0.01 to 18.50 ± 0.90 μM when compared with the standard inhibitor thiourea having IC 50 value 21.25 ± 0.90 μM. Among the series, analog 9 (0.14 ± 0.01 μM) with di-chloro substitution on phenyl ring was identified as the most potent inhibitor of urease. The structure activity relationship has been also established on the basis of binding interactions of the active analogs. These binding interactions were identified by molecular docking studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Raltegravir, elvitegravir, and metoogravir: the birth of "me-too" HIV-1 integrase inhibitors

    Directory of Open Access Journals (Sweden)

    Neamati Nouri

    2009-03-01

    Full Text Available Abstract Merck's MK-0518, known as raltegravir, has recently become the first FDA-approved HIV-1 integrase (IN inhibitor and has since risen to blockbuster drug status. Much research has in turn been conducted over the last few years aimed at recreating but optimizing the compound's interactions with the protein. Resulting me-too drugs have shown favorable pharmacokinetic properties and appear drug-like but, as expected, most have a highly similar interaction with IN to that of raltegravir. We propose that, based upon conclusions drawn from our docking studies illustrated herein, most of these me-too MK-0518 analogues may experience a low success rate against raltegravir-resistant HIV strains. As HIV has a very high mutational competence, the development of drugs with new mechanisms of inhibitory action and/or new active substituents may be a more successful route to take in the development of second- and third-generation IN inhibitors.

  15. Virtual screening of selective inhibitors of phosphopantetheine adenylyltransferase from Mycobacterium tuberculosis

    Science.gov (United States)

    Podshivalov, D. D.; Timofeev, V. I.; Sidorov-Biryukov, D. D.; Kuranova, I. P.

    2017-05-01

    Bacterial phosphopantetheine adenylyltransferase from Mycobacterium tuberculosis (PPAT Mt) is a convenient target protein for the directed search for selective inhibitors as potent antituberculosis drugs. Four compounds suitable for the detailed investigation of their interactions with PPAT Mt were found by virtual screening. The active-site region of the enzyme was chosen as the ligand-binding site. The positions of the ligands found by the docking were refined by molecular dynamics simulation. The nearest environment of the ligands, the positions of which in the active site of the enzyme were found in a computational experiment, was analyzed. The compounds under consideration were shown to directly interact with functionally important active-site amino-acid residues and block access of substrates to the active site. Therefore, these compounds can be used for the design of selective inhibitors of PPAT Mt as potent antituberculosis drugs.

  16. 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

  17. Rational Design of Rho Protein Inhibitors

    National Research Council Canada - National Science Library

    Rojas, Rafael J

    2006-01-01

    ... nucleotide exchange factors (RhoGEFs). We have developed a high throughput screening strategy identify novel inhibitors of Rho activation are currently following up on several compounds which appear to selectively inhibit Rho activation. These compounds may form the basis of future drug development strategies for the treatment of metastatic breast cancer.

  18. Rational Design of Rho Protein Inhibitors

    National Research Council Canada - National Science Library

    Rojas, Rafael J

    2005-01-01

    ... nucleotide exchange factors (RhoGEFs). We have developed a high throughput screening strategy identify novel inhibitors of Rho activation are currently following up on several compounds which appear to selectively inhibit Rho activation. These compounds may form the basis of future drug development strategies for the treatment of metastatic breast cancer.

  19. [Mechanisms and efficacy of SGLT2 inhibitors].

    Science.gov (United States)

    Shiba, Teruo

    2015-03-01

    SGLT2 is a low affinity, high capacity glucose co-transporter, almost exclusively expressed in the kidney cortex. Inhibition of SGLT2 has been shown to increase the daily 50g or more urinary glucose excretion, as compared to placebo, leading to a reduction in blood glucose levels and indicated only for the treatment of type 2 diabetes. In Japan 6 species of SGLT2 inhibitors have already been sold and reported to results in a decrease of FPG by 14.4 to 45.8 (mg/dL), in a reduction of HbA1c by 0.35 to 1.24% and in loss of body weight by 1.29 to 2.50(kg). There is less effect of the SGLT2 inhibitor in diabetic subjects with renal impairment and the reduction in HbA1c and FPG will be approximately half of the average in those with 30 ≤ eGFR ≤ 59. The position of SGLT2 inhibitors would be considered as the drug administered in combination or add-on therapy when the young obese type 2 diabetics without renal impairment has not yet reached to the glycemic target with other drugs although in AACE consensus statement of 2013, it has been shelved for inexperienced use with respect to the positioning of the SGLT2 inhibitors.

  20. 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...

  1. Vildagliptin: the first innovative DDP-4 inhibitor

    Directory of Open Access Journals (Sweden)

    Edvin Villkhauer

    2010-09-01

    Full Text Available A review of the main stages of investigation undertaken by Novartis Pharmaceuticals in search of a new molecule for the treatment of type 2 diabetesmellitus, dipeptidyl peptidase-4 (DPP-4 inhibitor (Vildaglyptin. The data on specificity and selectivity of the action of this molecule are presentedalong with the results of its comparison with another agent of this group (sitagliptin.

  2. Curcumin derivatives as HIV-1 protease inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Z.; Li, J.; Craik, C.S.; Ortiz de Montellano, P.R. [Univ. of California, San Francisco, CA (United States)

    1993-12-31

    Curcumin, a non-toxic natural compound from Curcuma longa, has been found to be an HIV-1 protease inhibitor. Some of its derivatives were synthesized and their inhibitory activity against the HIV-1 protease was tested. Curcumin analogues containing boron enhanced the inhibitory activity. At least of the the synthesized compounds irreversibly inhibits the HIV-1 protease.

  3. Dissolution properties of cerium dibutylphosphate corrosion inhibitors

    NARCIS (Netherlands)

    Soestbergen, van M.; Erich, S.J.F.; Huinink, H.P.; Adan, O.C.G.

    2013-01-01

    The corrosion inhibitor cerium dibutylphosphate, Ce(dbp)3, prevents corrosion by cerium and dbp deposition at the alkaline cathode and acidic anode respectively. The pH dependent Ce(dbp)3 solubility seems to play an essential role in the inhibition degree. We found that Ce(dbp)3 scarcely dissolves

  4. SEARCH OF NEW SYNTHETIC INHIBITORS OF TYROSINASE

    Directory of Open Access Journals (Sweden)

    Yu. Shesterenko

    2017-11-01

    Full Text Available Melanin pigmentation of skin plays the most important role in the protection of organism against UV-irradiation, but the excessive accumulation of melanin brings to toxic melanodermia, melasma, lentigo and other skin lesions. Tyrosinase is the key enzyme of skin melanin pigment biosynthesis. In spite of certain progress in investigation of natural and synthetic tyrosinase inhibitors, actuality of such studies is of a high level, because the existing inhibitors are in some cases unstable, expensive, toxic, requires complex methods of synthesis or isolation from natural sources. The aim of the work is screening of new tyrosinase inhibitors, using the enzyme, isolated from Agaricus bisporus. Tyrosinase was isolated from Agaricus bisporus mushrooms by a modified method. It was found, that the introduction of polyethylene glycol 4000 in the extraction process promotes 3-fold reduction of polyphenol content, which leads to increase purity of enzyme with an increase in its activity by 25%. A search for new tyrosinase inhibitors among a wide range of compounds, including derivatives of 3-chloro-1,4-naphthoquinone, isatin, 3-hydroxy-2-naphthoic acid, etc was conducted. The studied substances did not displayed inhibitory effect at concentration of 0,1-0,5 mmol/dm3.

  5. Peptide aldehyde inhibitors of bacterial peptide deformylases.

    Science.gov (United States)

    Durand, D J; Gordon Green, B; O'Connell, J F; Grant, S K

    1999-07-15

    Bacterial peptide deformylases (PDF, EC 3.5.1.27) are metalloenzymes that cleave the N-formyl groups from N-blocked methionine polypeptides. Peptide aldehydes containing a methional or norleucinal inhibited recombinant peptide deformylase from gram-negative Escherichia coli and gram-positive Bacillus subtilis. The most potent inhibitor was calpeptin, N-CBZ-Leu-norleucinal, which was a competitive inhibitor of the zinc-containing metalloenzymes, E. coli and B. subtilis PDF with Ki values of 26.0 and 55.6 microM, respectively. Cobalt-substituted E. coli and B. subtilis deformylases were also inhibited by these aldehydes with Ki values for calpeptin of 9.5 and 12.4 microM, respectively. Distinct spectral changes were observed upon binding of calpeptin to the Co(II)-deformylases, consistent with the noncovalent binding of the inhibitor rather than the formation of a covalent complex. In contrast, the chelator 1,10-phenanthroline caused the time-dependent inhibition of B. subtilis Co(II)-PDF activity with the loss of the active site metal. The fact that calpeptin was nearly equipotent against deformylases from both gram-negative and gram-positive bacterial sources lends further support to the idea that a single deformylase inhibitor might have broad-spectrum antibacterial activity. Copyright 1999 Academic Press.

  6. Current and Novel Inhibitors of HIV Protease

    Czech Academy of Sciences Publication Activity Database

    Pokorná, Jana; Machala, L.; Řezáčová, Pavlína; Konvalinka, Jan

    2009-01-01

    Roč. 1, č. 3 (2009), s. 1209-1239 ISSN 1999-4915 R&D Projects: GA MŠk 1M0508 Grant - others:GA AV ČR(CZ) IAAX00320901 Program:IA Institutional research plan: CEZ:AV0Z40550506 Keywords : HIV protease * protease inhibitor * HAART Subject RIV: CE - Biochemistry

  7. Proton pump inhibitors affect the gut microbiome

    NARCIS (Netherlands)

    Imhann, Floris; Bonder, Marc Jan; Vich Vila, Arnau; Fu, Jingyuan; Mujagic, Zlatan; Vork, Lisa; Feenstra, Ettje T.; Jankipersadsing, Soesma A; Cenit, Maria Carmen; Harmsen, Hermie J M; Dijkstra, Gerard; Franke, Lude; Xavier, Ramnik J; Jonkers, Daisy; Wijmenga, Cisca; Weersma, Rinse K; Zhernakova, Alexandra

    BACKGROUND AND AIMS: Proton pump inhibitors (PPIs) are among the top 10 most widely used drugs in the world. PPI use has been associated with an increased risk of enteric infections, most notably Clostridium difficile. The gut microbiome plays an important role in enteric infections, by resisting or

  8. Pharmacological caspase inhibitors: Research towards therapeutic perspectives

    Czech Academy of Sciences Publication Activity Database

    Kudělová, J.; Fleischmannová, J.; Adamová, E.; Matalová, Eva

    2015-01-01

    Roč. 66, č. 4 (2015), s. 473-482 ISSN 0867-5910 R&D Projects: GA ČR(CZ) GA14-28254S Institutional support: RVO:68081715 Keywords : caspase * caspase inhibitor * apoptosis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.804, year: 2015

  9. Pharmacological caspase inhibitors: Research towards therapeutic perspectives

    Czech Academy of Sciences Publication Activity Database

    Kudělová, J.; Fleischmannová, Jana; Adamová, Eva; Matalová, Eva

    2015-01-01

    Roč. 66, č. 4 (2015), s. 473-482 ISSN 0867-5910 R&D Projects: GA ČR GB14-37368G Institutional support: RVO:67985904 Keywords : caspase * caspase inhibitor * apoptosis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.804, year: 2015

  10. Discovery of inhibitors of bacterial histidine kinases

    NARCIS (Netherlands)

    Velikova, N.R.

    2014-01-01

    Discovery of Inhibitors of Bacterial Histidine Kinases Summary

    The thesis is on novel antibacterial drug discovery (http://youtu.be/NRMWOGgeysM). Using structure-based and fragment-based drug discovery approach, we have identified small-molecule histidine-kinase

  11. Novel peptide-based protease inhibitors

    DEFF Research Database (Denmark)

    Roodbeen, Renée

    of novel peptide-based protease inhibitors, efforts were made towards improved methods for peptide synthesis. The coupling of Fmoc-amino acids onto N-methylated peptidyl resins was investigated. These couplings can be low yielding and the effect of the use of microwave heating combined with the coupling...

  12. Oestrogen, testosterone, cytotoxin and cholinesterase inhibitor ...

    African Journals Online (AJOL)

    Oestrogen, testosterone, cytotoxin and cholinesterase inhibitor removal during reclamation of sewage to drinking water. ... Risks associated with sewage effluent and reclaimed sewage should be closely monitored; therefore water at the Gammams Sewage Treatment Plant (GSTP) inlet and outlet, as well as reclaimed water ...

  13. Interaction graphs

    DEFF Research Database (Denmark)

    Seiller, Thomas

    2016-01-01

    Interaction graphs were introduced as a general, uniform, construction of dynamic models of linear logic, encompassing all Geometry of Interaction (GoI) constructions introduced so far. This series of work was inspired from Girard's hyperfinite GoI, and develops a quantitative approach that should...... be understood as a dynamic version of weighted relational models. Until now, the interaction graphs framework has been shown to deal with exponentials for the constrained system ELL (Elementary Linear Logic) while keeping its quantitative aspect. Adapting older constructions by Girard, one can clearly define...... "full" exponentials, but at the cost of these quantitative features. We show here that allowing interpretations of proofs to use continuous (yet finite in a measure-theoretic sense) sets of states, as opposed to earlier Interaction Graphs constructions were these sets of states were discrete (and finite...

  14. Embarrassing Interactions

    DEFF Research Database (Denmark)

    Deterding, Sebastian; Lucero, Andrés; Holopainen, Jussi

    2015-01-01

    Wherever the rapid evolution of interactive technologies disrupts standing situational norms, creates new, often unclear situational audiences, or crosses cultural boundaries, embarrassment is likely. This makes embarrassment a fundamental adoption and engagement hurdle, but also a creative design...

  15. Diffractive interactions

    International Nuclear Information System (INIS)

    Del Duca, V.; Marage, P.

    1996-08-01

    The general framework of diffractive deep inelastic scattering is introduced and reports given in the session on diffractive interactions at the international workshop on deep-inelastic scattering and related phenomena, Rome, April 1996, are presented. (orig.)

  16. Exploring the water-binding pocket of the type II dehydroquinase enzyme in the structure-based design of inhibitors.

    Science.gov (United States)

    Blanco, Beatriz; Sedes, Antía; Peón, Antonio; Otero, José M; van Raaij, Mark J; Thompson, Paul; Hawkins, Alastair R; González-Bello, Concepción

    2014-04-24

    Structural and computational studies to explore the WAT1 binding pocket in the structure-based design of inhibitors against the type II dehydroquinase (DHQ2) enzyme are reported. The crystal structures of DHQ2 from M. tuberculosis in complex with four of the reported compounds are described. The electrostatic interaction observed between the guanidinium group of the essential arginine and the carboxylate group of one of the inhibitors in the reported crystal structures supports the recently suggested role of this arginine as the residue that triggers the release of the product from the active site. The results of the structural and molecular dynamics simulation studies revealed that the inhibitory potency is favored by promoting interactions with WAT1 and the residues located within this pocket and, more importantly, by avoiding situations where the ligands occupy the WAT1 binding pocket. The new insights can be used to advantage in the structure-based design of inhibitors.

  17. Interaction Widget

    DEFF Research Database (Denmark)

    Ingstrup, Mads

    2003-01-01

    This pattern describes the idea of making a user interface of discrete, reusable entities---here called interaction widgets. The idea behind widgets is described using two perspectives, that of the user and that of the developer. It is the forces from these two perspectives that are balanced...... in the pattern. The intended audience of the pattern is developers and researchers within the field of human computer interaction....

  18. Hair Interactions

    OpenAIRE

    Cani , Marie-Paule; Bertails , Florence

    2006-01-01

    International audience; Processing interactions is one of the main challenges in hair animation. Indeed, in addition to the collisions with the body, an extremely large number of contacts with high friction rates are permanently taking place between individual hair strands. Simulating the latter is essential: without hair self-interactions, strands would cross each other during motion or come to rest at the same location, yielding unrealistic behavior and a visible lack of hair volume. This c...

  19. [Terbinafine : Relevant drug interactions and their management].

    Science.gov (United States)

    Dürrbeck, A; Nenoff, P

    2016-09-01

    The allylamine terbinafine is the probably most frequently prescribed systemic antifungal agent in Germany for the treatment of dermatomycoses and onychomycoses. According to the German drug law, terbinafine is approved for patients who are 18 years and older; however, this antifungal agent is increasingly used off-label for treatment of onychomycoses and tinea capitis in children. Terbinafine is associated with only a few interactions with other drugs, which is why terbinafine can generally be used without problems in older and multimorbid patients. Nevertheless, some potential interactions of terbinafine with certain drug substances are known, including substances of the group of antidepressants/antipsychotics and some cardiovascular drugs. Decisive for the relevance of interactions is-along with the therapeutic index of the substrate and the possible alternative degradation pathways-the genetically determined type of metabolism. When combining terbinafine with tricyclic antidepressants or selective serotonin reuptake inhibitors and serotonin/noradrenalin reuptake inhibitors, the clinical response and potential side effects must be monitored. Problematic is the use of terbinafine with simultaneous treatment with tamoxifen. The administration of potent CYP2D6 inhibitors leads to a diminished efficacy of tamoxifen because one of its most important active metabolites-endoxifen-is not sufficiently available. Therefore, combination of tamoxifen and terbinafine should be avoided. In conclusion, the number of substances which are able to cause clinically relevant interactions in case of simultaneously administration with terbinafine is clear and should be manageable in the dermatological office with adequate monitoring.

  20. Dry eye syndrome in aromatase inhibitor users.

    Science.gov (United States)

    Turaka, Kiran; Nottage, Jennifer M; Hammersmith, Kristin M; Nagra, Parveen K; Rapuano, Christopher J

    2013-04-01

    Aromatase inhibitors are frequently used as an adjuvant therapy in the treatment of breast cancer. We observed that several patients taking aromatase inhibitors presented with severe dry eye symptoms, and we investigated whether there is a relationship between aromatase inhibitors and dry eyes in these patients. Retrospective chart review. Forty-one women. A computerized search of health records was performed to identify patients using anastrazole, letrozole and exemestane seen by the Cornea Service from August 2008 to March 2011. The results were compared with age-matched controls. Ocular surface changes among aromatase inhibitors users. Of the 41 women, 39 were Caucasians. Thirty-nine patients had breast cancer (95%), one patient had ovarian cancer (2.5%) and one had an unknown primary cancer. Mean age was 68 ± 11.3 years (range 47-95). Most common presenting symptoms were blurred vision in 28 (68%) patients, irritation/foreign body sensation in 12 (29%) patients, redness in 9 (22%) patients, tearing in 6 (22%) patients and photosensitivity in 2 (5%) patients. Mean Schirmer's test measurement was 11 ± 5.8 mm (range 0.5-20 mm). Blepharitis was noted in 68 of 82 eyes (73%), decreased or poor tear function in 24 eyes (29%), conjunctival injection in 18 eyes (22%) and superficial punctate keratitis in 12 eyes (29%). Among an age-matched population (45-95 years), dry eye syndrome was found in only 9.5% of patients. Because the prevalence of ocular surface disease signs and symptoms appears to be higher in study group than control patients, aromatase inhibitors might be a contributing factor to the dry eye symptoms. © 2012 The Authors. Clinical and Experimental Ophthalmology © 2012 Royal Australian and New Zealand College of Ophthalmologists.

  1. RENAL SAFETY OF PROTON PUMP INHIBITORS

    Directory of Open Access Journals (Sweden)

    A. I. Dyadyk

    2017-01-01

    Full Text Available Proton pump inhibitors are a widely used in clinical practice, and are taken by millions of patients around the world for a long time. While proton pump inhibitors are well-tolerated class of drugs, the number of publications has been raised about adverse renal effects, specially their association with acute tubulointerstitial nephritis. It is one of the leading causes of acute renal injury and have catastrophic long-term consequences called chronic kidney disease. In this review, we consider epidemiology, pathogenesis, diagnostic criteria (including biopsy and morphological pattern, clinical manifestations and treatment of proton pump inhibitors-induced acute tubulointerstitial nephritis. A subclinical course without classical manifestations of a cell-mediated hypersensitivity reaction (fever, skin rash, eosinophilia, arthralgia is characteristic of acute tubulointerstitial nephritis. Increased serum creatinine, decreased glomerular filtration rate, electrolyte disorders, pathological changes in urine tests are not highly specific indicators, but allow to suspect the development of acute tubulointerstitial nephritis. The “gold” standard of diagnosis is the intravital morphological examination of the kidney tissue. Timely diagnosis and immediate discontinuation of the potentially causative drug is the mainstay of therapy and the first necessary step in the early management of suspected or biopsy-proven drug-induced acute tubulointerstitial nephritis. The usage of proton pump inhibitors should be performed only on strict indications with optimal duration of treatment and careful monitoring of kidney function. Multiple comorbidities (older age, heart failure, diabetes, cirrhosis, chronic kidney disease, hypovolemia increase potential nephrotoxicity. Awareness of this iatrogenic complication will improve diagnosis of proton pump inhibitors-induced acute tubulointerstitial nephritis by multidisciplinary specialists and increase the possibility

  2. Cost of care of haemophilia with inhibitors.

    Science.gov (United States)

    Di Minno, M N D; Di Minno, G; Di Capua, M; Cerbone, A M; Coppola, A

    2010-01-01

    In Western countries, the treatment of patients with inhibitors is presently the most challenging and serious issue in haemophilia management, direct costs of clotting factor concentrates accounting for >98% of the highest economic burden absorbed for the healthcare of patients in this setting. Being designed to address questions of resource allocation and effectiveness, decision models are the golden standard to reliably assess the overall economic implications of haemophilia with inhibitors in terms of mortality, bleeding-related morbidity, and severity of arthropathy. However, presently, most data analyses stem from retrospective short-term evaluations, that only allow for the analysis of direct health costs. In the setting of chronic diseases, the cost-utility analysis, that takes into account the beneficial effects of a given treatment/healthcare intervention in terms of health-related quality of life, is likely to be the most appropriate approach. To calculate net benefits, the quality adjusted life year, that significantly reflects such health gain, has to be compared with specific economic impacts. Differences in data sources, in medical practice and/or in healthcare systems and costs, imply that most current pharmacoeconomic analyses are confined to a narrow healthcare payer perspective. Long-term/lifetime prospective or observational studies, devoted to a careful definition of when to start a treatment; of regimens (dose and type of product) to employ, and of inhibitor population (children/adults, low-responding/high responding inhibitors) to study, are thus urgently needed to allow for newer insights, based on reliable data sources into resource allocation, effectiveness and cost-utility analysis in the treatment of haemophiliacs with inhibitors.

  3. Human inter-α-inhibitor is a substrate for factor XIIIa and tissue transglutaminase

    DEFF Research Database (Denmark)

    Sonne-Schmidt, Carsten Scavenius; Sanggaard, Kristian W; Nikolajsen, Camilla L

    2011-01-01

    that inter-α-inhibitor is cross-linked to the fibrin clot in a 1:20 ratio relative to the known factor XIIIa substrate α2-antiplasmin. This interaction may protect fibrin or other Lys-donating proteins from adventitious proteolysis by increasing the local concentration of bikunin. In addition, the reaction...... may influence the TSG-6/heavy Chain 2-mediated transfer of heavy chains observed during inflammation....

  4. Engineering the substrate and inhibitor specificities of human coagulation Factor VIIa

    DEFF Research Database (Denmark)

    Larsen, Katrine S; Østergaard, Henrik; Bjelke, Jais R

    2007-01-01

    The remarkably high specificity of the coagulation proteases towards macromolecular substrates is provided by numerous interactions involving the catalytic groove and remote exosites. For FVIIa [activated FVII (Factor VII)], the principal initiator of coagulation via the extrinsic pathway, several...... for FVIIa by marked changes in primary substrate specificity and decreased rates of antithrombin III inhibition. Interestingly, these changes do not necessarily coincide with an altered ability to activate Factor X, demonstrating that inhibitor and macromolecular substrate selectivity may be engineered...

  5. A fluvoxamine-caffeine interaction study

    DEFF Research Database (Denmark)

    Jeppesen, U; Loft, S; Poulsen, H E

    1996-01-01

    The selective serotonin reuptake inhibitor fluvoxamine is a very potent inhibitor of the liver enzyme CYP1A2, which is the major P450 catalysing the biotransformation of caffeine. Thus, a pharmacokinetic study was undertaken with the purpose of documenting a drug-drug interaction between fluvoxam......The selective serotonin reuptake inhibitor fluvoxamine is a very potent inhibitor of the liver enzyme CYP1A2, which is the major P450 catalysing the biotransformation of caffeine. Thus, a pharmacokinetic study was undertaken with the purpose of documenting a drug-drug interaction between...... fluvoxamine and caffeine. The study was carried out as a randomized, in vivo, cross-over study including eight healthy volunteers. In Period A of the study, each subject took 200 mg caffeine orally, and in Period B, the subjects took fluvoxamine 50 mg per day for 4 days and 100 mg per day for 8 days. On day 8...... fluvoxamine treatment may lead to caffeine intoxication. Finally, our study provides additional evidence that fluvoxamine can be used to probe CYP1A2 in drug metabolism....

  6. DARC: Mapping Surface Topography by Ray-Casting for Effective Virtual Screening at Protein Interaction Sites.

    Science.gov (United States)

    Gowthaman, Ragul; Miller, Sven A; Rogers, Steven; Khowsathit, Jittasak; Lan, Lan; Bai, Nan; Johnson, David K; Liu, Chunjing; Xu, Liang; Anbanandam, Asokan; Aubé, Jeffrey; Roy, Anuradha; Karanicolas, John

    2016-05-12

    Protein-protein interactions represent an exciting and challenging target class for therapeutic intervention using small molecules. Protein interaction sites are often devoid of the deep surface pockets presented by "traditional" drug targets, and crystal structures reveal that inhibitors typically engage these sites using very shallow binding modes. As a consequence, modern virtual screening tools developed to identify inhibitors of traditional drug targets do not perform as well when they are instead deployed at protein interaction sites. To address the need for novel inhibitors of important protein interactions, here we introduce an alternate docking strategy specifically designed for this regime. Our method, termed DARC (Docking Approach using Ray-Casting), matches the topography of a surface pocket "observed" from within the protein to the topography "observed" when viewing a potential ligand from the same vantage point. We applied DARC to carry out a virtual screen against the protein interaction site of human antiapoptotic protein Mcl-1 and found that four of the top-scoring 21 compounds showed clear inhibition in a biochemical assay. The Ki values for these compounds ranged from 1.2 to 21 μM, and each had ligand efficiency comparable to promising small-molecule inhibitors of other protein-protein interactions. These hit compounds do not resemble the natural (protein) binding partner of Mcl-1, nor do they resemble any known inhibitors of Mcl-1. Our results thus demonstrate the utility of DARC for identifying novel inhibitors of protein-protein interactions.

  7. Structural studies of series HIV-1 nonnucleoside reverse transcriptase inhibitors 1-(2,6-difluorobenzyl)-2-(2,6-difluorophenyl)-benzimidazoles with different 4-substituents

    Science.gov (United States)

    Ziółkowska, Natasza E.; Michejda, Christopher J.; Bujacz, Grzegorz D.

    2010-03-01

    Over the past 10 years, several anti-viral drugs have become available to fight the HIV infection. Antiretroviral treatment reduces the mortality of AIDS. Nonnucleoside inhibitors of HIV-1 reverse transcriptase are specific and potentially nontoxic drugs against AIDS. The crystal structures of five nonnucleoside inhibitors of HIV-1 reverse transcriptase are presented here. The structural parameters, especially those describing the angular orientation of the π-electron systems and influencing biological activity, were determined for all of the investigated inhibitors. The chemical character and orientation of the substituent at C4 position of the benzimidazole moiety substantially influences the anti-viral activity. The structural data of the investigated inhibitors is a good basis for modeling enzyme-inhibitor interactions for structure-assisted drug design.

  8. Cytogenetic study of Ascaris trypsin inhibitor in cultured human ...

    Indian Academy of Sciences (India)

    2009-04-01

    Apr 1, 2009 ... Although the physical and chemical properties of Ascaris trypsin inhibitors ... male of Ascaris suum according to the method of Pudles and. Rola (1967). ..... inhibitor isolated from Ascaris resulted in the appearance of dominant ...

  9. SGLT2 inhibitors: molecular design and potential differences in effect.

    Science.gov (United States)

    Isaji, Masayuki

    2011-03-01

    The physiological and pathological handling of glucose via sodium-glucose cotransporter-2 (SGLT2) in the kidneys has been evolving, and SGLT2 inhibitors have been focused upon as a novel drug for treating diabetes. SGLT2 inhibitors enhance renal glucose excretion by inhibiting renal glucose reabsorption. Consequently, SGLT2 inhibitors reduce plasma glucose insulin independently and improve insulin resistance in diabetes. To date, various SGLT2 inhibitors have been developed and evaluated in clinical studies. The potency and positioning of SGLT2 inhibitors as an antidiabetic drug are dependent on their characteristic profile, which induces selectivity, efficacy, pharmacokinetics, and safety. This profile decides which SGLT2 inhibitors can be expected for application of the theoretical concept of reducing renal glucose reabsorption for the treatment of diabetes. I review the structure and advancing profile of various SGLT2 inhibitors, comparing their similarities and differences, and discuss the expected SGLT2 inhibitors for an emerging category of antidiabetic drugs.

  10. Environmental life cycle analysis of potato sprout inhibitors

    NARCIS (Netherlands)

    Kerstholt, R.P.V.; Ree, C.M.; Moll, H.C.

    Potato sprout inhibitors are generally applied to suppress sprouting during winter storage. This study presents the compared environmental profiles of the two sprout inhibitors available on the Dutch market: A traditional chemical product with isopropyl-3-chlorophenylcarbamate (CIPC) and

  11. [Inhibitors of proteolytic enzymes under abiotic stresses in plants (review)].

    Science.gov (United States)

    Mosolov, V V; Valueva, T A

    2011-01-01

    Data on the role of proteolytic enzyme inhibitors in plant adaptation to various unfavorable environmental abiotic factors--water deficiency, salinization of soil, extreme temperatures, etc.--and also probable functions of proteinases inhibitors in natural plant senescense are considered.

  12. 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.

  13. Insights on Cytochrome P450 Enzymes and Inhibitors Obtained Through QSAR Studies

    Directory of Open Access Journals (Sweden)

    Maryam Foroozesh

    2012-08-01

    Full Text Available The cytochrome P450 (CYP superfamily of heme enzymes play an important role in the metabolism of a large number of endogenous and exogenous compounds, including most of the drugs currently on the market. Inhibitors of CYP enzymes have important roles in the treatment of several disease conditions such as numerous cancers and fungal infections in addition to their critical role in drug-drug interactions. Structure activity relationships (SAR, and three-dimensional quantitative structure activity relationships (3D-QSAR represent important tools in understanding the interactions of the inhibitors with the active sites of the CYP enzymes. A comprehensive account of the QSAR studies on the major human CYPs 1A1, 1A2, 1B1, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1, 3A4 and a few other CYPs are detailed in this review which will provide us with an insight into the individual/common characteristics of the active sites of these enzymes and the enzyme-inhibitor interactions.

  14. Virtual analysis of structurally diverse synthetic analogs as inhibitors of snake venom secretory phospholipase A2.

    Science.gov (United States)

    Sivaramakrishnan, V; Ilamathi, M; Ghosh, K S; Sathish, S; Gowda, T V; Vishwanath, B S; Rangappa, K S; Dhananjaya, B L

    2016-01-01

    Due to the toxic pathophysiological role of snake venom phospholipase A2 (PLA2 ), its compelling limitations to anti-venom therapy in humans and the need for alternative therapy foster considerable pharmacological interest towards search of PLA2 specific inhibitors. In this study, an integrated approach involving homology modeling, molecular dynamics and molecular docking studies on VRV-PL-V (Vipera russellii venom phospholipase A2 fraction-V) belonging to Group II-B secretory PLA2 from Daboia russelli pulchella is carried out in order to study the structure-based inhibitor design. The accuracy of the model was validated using multiple computational approaches. The molecular docking study of this protein was undertaken using different classes of experimentally proven, structurally diverse synthetic inhibitors of secretory PLA2 whose selection is based on IC50 value that ranges from 25 μM to 100 μM. Estimation of protein-ligand contacts by docking analysis sheds light on the importance of His 47 and Asp 48 within the VRV-PL-V binding pocket as key residue for hydrogen bond interaction with ligands. Our virtual analysis revealed that compounds with different scaffold binds to the same active site region. ADME analysis was also further performed to filter and identify the best potential specific inhibitor against VRV-PL-V. Additionally, the e-pharmacophore was generated for the best potential specific inhibitor against VRV-PL-V and reported here. The present study should therefore play a guiding role in the experimental design of VRV-PL-V inhibitors that may provide better therapeutic molecular models for PLA2 recognition and anti-ophidian activity. Copyright © 2015 John Wiley & Sons, Ltd.

  15. 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

  16. 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

  17. Two distinct expression patterns of urokinase, urokinase receptor and plasminogen activator inhibitor-1 in colon cancer liver metastases

    DEFF Research Database (Denmark)

    Illemann, Martin; Bird, Nigel; Majeed, Ali

    2009-01-01

    Metastatic growth and invasion by colon cancer cells in the liver requires the ability of the cancer cells to interact with the new tissue environment. Plasmin(ogen) is activated on cell surfaces by urokinase-type PA (uPA), and is regulated by uPAR and plasminogen activator inhibitor-1 (PAI-1). T...

  18. Comparisons of Prostate Cancer Inhibitors Abiraterone and TOK-001 Binding with CYP17A1 through Molecular Dynamics

    Directory of Open Access Journals (Sweden)

    Fei Xiao

    2015-01-01

    However, biology-driven inhibitor development of prostate cancer is poorly elucidated. The aims of this study are to address structural differences at atomic-level between CYP17A1 and inhibitors i.e., abiraterone and TOK-001, and further investigate the effect of point mutation of CYP17A1 on the active site stability and the local interactions that are hydrophobic interaction and hydrogen bonding throughout molecular dynamics (MD simulation. After performing multiple comparisons among four different complexes across CYP17A1 and inhibitors, interestingly TOK-001 oriented toward the active pocket and formed larger volume with I-helix of CYP17A1 than abiraterone, whereas abiraterone showed tighter binding and more active site stability. Considering on the effect of hydrophobic interaction and hydrogen bonding between abiraterone and CYP17A1, the key residues of Phe114, Ile371, Val482, and Asn202 were identified. This contributes into tight binding interactions; however abiraterone is effectively weakened along with the global conformation mobility increased in A105L mutation. Surprisingly, overall conformation of the CYP17A1 remained stable when bound to TOK-001. This basic knowledge can guide future experiments on design of efficient inhibitors for CYP17A1, which provides theoretical basis of androgen-dependent disease therapy.

  19. [Noncovalent cation-π interactions--their role in nature].

    Science.gov (United States)

    Fink, Krzysztof; Boratyński, Janusz

    2014-11-07

    Non-covalent interactions play an extremely important role in organisms. The main non-covalent interactions in nature are: ion-ion interactions, dipole-dipole interactions, hydrogen bonds, and van der Waals interactions. A new kind of intermolecular interactions--cation-π interactions--is gaining increasing attention. These interactions occur between a cation and a π system. The main contributors to cation-π interactions are electrostatic, polarization and, to a lesser extent, dispersion interactions. At first, cation-π interactions were studied in a gas phase, with metal cation-aromatic system complexes. The characteristics of these complexes are as follows: an increase of cation atomic number leads to a decrease of interaction energy, and an increase of cation charge leads to an increase of interaction energy. Aromatic amino acids bind with metal cations mainly through interactions with their main chain. Nevertheless, cation-π interaction with a hydrophobic side chain significantly enhances binding energy. In water solutions most cations preferentially interact with water molecules rather than aromatic systems. Cation-π interactions occur in environments with lower accessibility to a polar solvent. Cation-π interactions can have a stabilizing role on the secondary, tertiary and quaternary structure of proteins. These interactions play an important role in substrate or ligand binding sites in many proteins, which should be taken into consideration when the screening of effective inhibitors for these proteins is carried out. Cation-π interactions are abundant and play an important role in many biological processes.

  20. 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.

  1. Computational design of a PDZ domain peptide inhibitor that rescues CFTR activity.

    Directory of Open Access Journals (Sweden)

    Kyle E Roberts

    Full Text Available The cystic fibrosis transmembrane conductance regulator (CFTR is an epithelial chloride channel mutated in patients with cystic fibrosis (CF. The most prevalent CFTR mutation, ΔF508, blocks folding in the endoplasmic reticulum. Recent work has shown that some ΔF508-CFTR channel activity can be recovered by pharmaceutical modulators ("potentiators" and "correctors", but ΔF508-CFTR can still be rapidly degraded via a lysosomal pathway involving the CFTR-associated ligand (CAL, which binds CFTR via a PDZ interaction domain. We present a study that goes from theory, to new structure-based computational design algorithms, to computational predictions, to biochemical testing and ultimately to epithelial-cell validation of novel, effective CAL PDZ inhibitors (called "stabilizers" that rescue ΔF508-CFTR activity. To design the "stabilizers", we extended our structural ensemble-based computational protein redesign algorithm K* to encompass protein-protein and protein-peptide interactions. The computational predictions achieved high accuracy: all of the top-predicted peptide inhibitors bound well to CAL. Furthermore, when compared to state-of-the-art CAL inhibitors, our design methodology achieved higher affinity and increased binding efficiency. The designed inhibitor with the highest affinity for CAL (kCAL01 binds six-fold more tightly than the previous best hexamer (iCAL35, and 170-fold more tightly than the CFTR C-terminus. We show that kCAL01 has physiological activity and can rescue chloride efflux in CF patient-derived airway epithelial cells. Since stabilizers address a different cellular CF defect from potentiators and correctors, our inhibitors provide an additional therapeutic pathway that can be used in conjunction with current methods.

  2. Combining aspirin with angiotensin converting enzyme inhibitors in heart failure: how safe is it?

    Science.gov (United States)

    Mehta, H; Mahajan, A; Bansal, N; Vaidya, S; Pathak, L

    1998-11-01

    The above discussion on the interaction of aspirin and ACE inhibitors seems to suggest that aspirin in high doses may have adverse interaction with ACE inhibitors in patients with heart failure but the data obtained is not sufficient or conclusive to recommended omission of aspirin in patients with heart failure. This raises a query in the mind of the physician whether to use a combination or not? The role of aspirin in the early period after myocardial infarction is well established so is the role of ACE inhibitors. Hence in patients with myocardial infarction and preserved left ventricular function it would not be wrong to administer combination of ACE inhibitors and aspirin. Albeit at a lower dose. In patients with large myocardial infarction or heart failure, warfarin may be an option but still needs to be documented in large trials. As suggested long term use of aspirin after infarction is still ambiguous and may be harmful in patients with heart failure with its anticedent side effects. But long term benefits of ACE inhibitors in heart failure are well documented. Hence if a choice has to be made whether to discontinue either of the two drugs it would be preferable to stop the aspirin. To answer the issue of use of aspirin in patients with heart failure it would be essential to conduct a double blind randomized trial comparing known anti-thrombotic treatment, aspirin and anti-coagulants on mortality in patients with heart failure, especially caused by coronary artery disease. Such a trial is underway at the present and till the results are available it should be left to clinical judgement of the physician whether to administer aspirin in patients with heart failure after weighing the benefits versus risk.

  3. Structural Insights into TMB-1 and the Role of Residues 119 and 228 in Substrate and Inhibitor Binding.

    Science.gov (United States)

    Skagseth, Susann; Christopeit, Tony; Akhter, Sundus; Bayer, Annette; Samuelsen, Ørjan; Leiros, Hanna-Kirsti S

    2017-08-01

    Metallo-β-lactamases (MBLs) threaten the effectiveness of β-lactam antibiotics, including carbapenems, and are a concern for global public health. β-Lactam/β-lactamase inhibitor combinations active against class A and class D carbapenemases are used, but no clinically useful MBL inhibitor is currently available. Tripoli metallo-β-lactamase-1 (TMB-1) and TMB-2 are members of MBL subclass B1a, where TMB-2 is an S228P variant of TMB-1. The role of S228P was studied by comparisons of TMB-1 and TMB-2, and E119 was investigated through the construction of site-directed mutants of TMB-1, E119Q, E119S, and E119A (E119Q/S/A). All TMB variants were characterized through enzyme kinetic studies. Thermostability and crystallization analyses of TMB-1 were performed. Thiol-based inhibitors were investigated by determining the 50% inhibitory concentrations (IC 50 ) and binding using surface plasmon resonance (SPR) for analysis of TMB-1. Thermostability measurements found TMB-1 to be stabilized by high NaCl concentrations. Steady-state enzyme kinetics analyses found substitutions of E119, in particular, substitutions associated with the penicillins, to affect hydrolysis to some extent. TMB-2 with S228P showed slightly reduced catalytic efficiency compared to TMB-1. The IC 50 levels of the new thiol-based inhibitors were 0.66 μM (inhibitor 2a) and 0.62 μM (inhibitor 2b), and the equilibrium dissociation constant ( K D ) of inhibitor 2a was 1.6 μM; thus, both were more potent inhibitors than l-captopril (IC 50 = 47 μM; K D = 25 μM). The crystal structure of TMB-1 was resolved to 1.75 Å. Modeling of inhibitor 2b in the TMB-1 active site suggested that the presence of the W64 residue results in T-shaped π-π stacking and R224 cation-π interactions with the phenyl ring of the inhibitor. In sum, the results suggest that residues 119 and 228 affect the catalytic efficiency of TMB-1 and that inhibitors 2a and 2b are more potent inhibitors for TMB-1 than l-captopril. Copyright

  4. Comparative studies on the human serum albumin binding of the clinically approved EGFR inhibitors gefitinib, erlotinib, afatinib, osimertinib and the investigational inhibitor KP2187.

    Science.gov (United States)

    Dömötör, Orsolya; Pelivan, Karla; Borics, Attila; Keppler, Bernhard K; Kowol, Christian R; Enyedy, Éva A

    2018-05-30

    Binding interactions between human serum albumin (HSA) and four approved epidermal growth factor receptor (EGFR) inhibitors gefitinib (GEF), erlotinib (ERL), afatinib (AFA), osimertinib (OSI), as well as the experimental drug KP2187, were investigated by means of spectrofluorometric and molecular modelling methods. Steady-state and time resolved spectrofluorometric techniques were carried out, including direct quenching of protein fluorescence and site marker displacement measurements. Proton dissociation processes and solvent dependent fluorescence properties were investigated as well. The EGFR inhibitors were predominantly presented in their single protonated form (HL + ) at physiological pH except ERL, which is charge-neutral. Significant solvent dependent fluorescence properties were found for GEF, ERL and KP2187, namely their emission spectra show strong dependence on the polarity and the hydrogen bonding ability of the solvents. The inhibitors proved to be bound at site I of HSA (in subdomain IIA) in a weak-to-moderate fashion (logK' 3.9-4.9) using spectrofluorometry. OSI (logK' 4.3) and KP2187 can additionally bind in site II (in subdomain IIIA), while GEF, ERL and AFA clearly show no interaction here. Docking methods qualitatively confirmed binding site preferences of compounds GEF and KP2187, and indicated that they probably bind to HSA in their neutral forms. Binding constants calculated on the basis of the various experimental data indicate a weak-to-moderate binding on HSA, only OSI exhibits somewhat higher affinity towards this protein. However, model calculations performed at physiological blood concentrations of HSA resulted in high (ca. 90%) bound fractions for the inhibitors, highlighting the importance of plasma protein binding. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Cellular growth kinetics distinguish a cyclophilin inhibitor from an HSP90 inhibitor as a selective inhibitor of hepatitis C virus.

    Directory of Open Access Journals (Sweden)

    Rudolf K F Beran

    Full Text Available During antiviral drug discovery, it is critical to distinguish molecules that selectively interrupt viral replication from those that reduce virus replication by adversely affecting host cell viability. In this report we investigate the selectivity of inhibitors of the host chaperone proteins cyclophilin A (CypA and heat-shock protein 90 (HSP90 which have each been reported to inhibit replication of hepatitis C virus (HCV. By comparing the toxicity of the HSP90 inhibitor, 17-(Allylamino-17-demethoxygeldanamycin (17-AAG to two known cytostatic compounds, colchicine and gemcitabine, we provide evidence that 17-AAG exerts its antiviral effects indirectly through slowing cell growth. In contrast, a cyclophilin inhibitor, cyclosporin A (CsA, exhibited selective antiviral activity without slowing cell proliferation. Furthermore, we observed that 17-AAG had little antiviral effect in a non-dividing cell-culture model of HCV replication, while CsA reduced HCV titer by more than two orders of magnitude in the same model. The assays we describe here are useful for discriminating selective antivirals from compounds that indirectly affect virus replication by reducing host cell viability or slowing cell growth.

  6. 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.

  7. Interactive governance

    DEFF Research Database (Denmark)

    Sørensen, Eva; Torfing, Jacob; Peters, B. Guy

    Governance has become one of the most commonly used concepts in contemporary political science. It is, however, often used to mean a variety of different things. This book helps to clarify this conceptual muddle by concentrating on one variety of governance-interactive governance. The authors argue...... that although the state may remain important for many aspects of governing, interactions between state and society represent an important, and perhaps increasingly important, dimension of governance. These interactions may be with social actors such as networks, with market actors or with other governments......, but all these forms represent means of governing involving mixtures of state action with the actions of other entities.This book explores thoroughly this meaning of governance, and links it to broader questions of governance. In the process of explicating this dimension of governance the authors also...

  8. Multiquark interactions

    International Nuclear Information System (INIS)

    Luk'yanov, V.K.

    1984-01-01

    To study multiquark interactions (MQI) the data of experiments confirming the presence of 3q, 6q, 12q states in interacting nuclear nucleons, in hadron- and lepton-nuclear processes at high energies and high momentum transfers are considered. Experimental data on cumulative processes pointing to the existence of MQI are analyzed. Two-channel model of a nucleus (the model of interacting nucleons) in the theory of coupled channels is discussed. The behaviour of form factor of deuteron and NQI (6q) contributions to ed scattering as well as deep inelastic scattering on nuclei are studied. The data known as EMC effect are discussed. It is pointed out that introduction of the notion MQI and consideration of a nucleus as a system of nucleons with a low MQI addition will help to explain such processes as cumulative reactions, form factors of a deuteron and light nuclei, deep inelastic scattering on nuclei

  9. Interaction region

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The Interaction Region Group addressed the basic questions of how to collide the SLC beams, how to maximize and monitor the luminosity, and how to minimize the detector backgrounds at the interaction region. In practice, five subgroups evolved to study these questions. The final focus group provided three alternative designs to acheive the 1 to 2 micron beam spot size required by the SLC, as well as studying other problems including: eta, eta' matching from the collider arcs, the implementation of soft bends near the interaction region, beam emittance growth, and magnet tolerances in the final focus. The beam position monitor group proposed two devices, a strip line monitor, and a beamstrahlung monitor, to bring the beams into collision. The luminosity monitor group reviewed the possible QED processes that would be insensitive to weak interaction (Z 0 ) effects. The beam dumping group proposed locations for kicker and septum magnets in the final focus that would achieve a high dumping efficiency and would meet the desired beam tolerances at the Moller scattering target in the beam dump line. Working with the Polarization Group, the Moller experiment was designed into the beam dump beam line. A beam dump was proposed that would maintain radiation backgrounds (penetrating muons) at acceptible levels. The detector backgrounds group proposed soft-bend and masking configurations to shield the detector from synchrotron radiation from the hard/soft bends and from the final focus quadrupoles and evaluated the effectiveness of these designs for the three final focus optics designs. Backgrounds were also estimated from: large angle synchrotron radiation, local and distant beam-gas interactions, 2-photon interactions, and from neutrons and backscattered photons from the beamstrahlung dump

  10. Cholinester