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Sample records for 5-lox inhibitor zileuton

  1. Deoxyhypusine Hydroxylase from Plasmodium vivax, the Neglected Human Malaria Parasite: Molecular Cloning, Expression and Specific Inhibition by the 5-LOX Inhibitor Zileuton

    PubMed Central

    Atemnkeng, Veronika Anyigoh; Pink, Mario; Schmitz-Spanke, Simone; Wu, Xian-Jun; Dong, Liang-Liang; Zhao, Kai-Hong; May, Caroline; Laufer, Stefan; Langer, Barbara; Kaiser, Annette

    2013-01-01

    Primaquine, an 8-aminoquinoline, is the only drug which cures the dormant hypnozoites of persistent liver stages from P. vivax. Increasing resistance needs the discovery of alternative pathways as drug targets to develop novel drug entities. Deoxyhypusine hydroxylase (DOHH) completes hypusine biosynthesis in eukaryotic initiation factor (eIF-5A) which is the only cellular protein known to contain the unusual amino acid hypusine. Modified EIF-5A is important for proliferation of the malaria parasite. Here, we present the first successful cloning and expression of DOHH from P. vivax causing tertiary malaria. The nucleic acid sequence of 1041 bp encodes an open reading frame of 346 amino acids. Histidine tagged expression of P. vivax DOHH detected a protein of 39.01 kDa in E. coli. The DOHH protein from P. vivax shares significant amino acid identity to the simian orthologues from P. knowlesi and P. yoelii strain H. In contrast to P. falciparum only four E-Z-type HEAT-like repeats are present in P. vivax DOHH with different homology to phycocyanin lyase subunits from cyanobacteria and in proteins participating in energy metabolism of Archaea and Halobacteria. However, phycocyanin lyase activity is absent in P. vivax DOHH. The dohh gene is present as a single copy gene and transcribed throughout the whole erythrocytic cycle. Specific inhibition of recombinant P. vivax DOHH is possible by complexing the ferrous iron with zileuton, an inhibitor of mammalian 5-lipoxygenase (5-LOX). Ferrous iron in the active site of 5-LOX is coordinated by three conserved histidines and the carboxylate of isoleucine673. Zileuton inhibited the P. vivax DOHH protein with an IC50 of 12,5 nmol determined by a relative quantification by GC/MS. By contrast, the human orthologue is only less affected with an IC50 of 90 nmol suggesting a selective iron-complexing strategy for the parasitic enzyme. PMID:23505486

  2. Structure and Ligand Based Drug Design Strategies in the Development of Novel 5-LOX Inhibitors

    PubMed Central

    Aparoy, Polamarasetty; Kumar Reddy, Kakularam; Reddanna, Pallu

    2012-01-01

    Lipoxygenases (LOXs) are non-heme iron containing dioxygenases involved in the oxygenation of polyunsaturated fatty acids (PUFAs) such as arachidonic acid (AA). Depending on the position of insertion of oxygen, LOXs are classified into 5-, 8-, 9-, 12- and 15-LOX. Among these, 5-LOX is the most predominant isoform associated with the formation of 5-hydroperoxyeicosatetraenoic acid (5-HpETE), the precursor of non-peptido (LTB4) and peptido (LTC4, LTD4, and LTE4) leukotrienes. LTs are involved in inflammatory and allergic diseases like asthma, ulcerative colitis, rhinitis and also in cancer. Consequently 5-LOX has become target for the development of therapeutic molecules for treatment of various inflammatory disorders. Zileuton is one such inhibitor of 5-LOX approved for the treatment of asthma. In the recent times, computer aided drug design (CADD) strategies have been applied successfully in drug development processes. A comprehensive review on structure based drug design strategies in the development of novel 5-LOX inhibitors is presented in this article. Since the crystal structure of 5-LOX has been recently solved, efforts to develop 5-LOX inhibitors have mostly relied on ligand based rational approaches. The present review provides a comprehensive survey on these strategies in the development of 5-LOX inhibitors. PMID:22680930

  3. Zileuton, 5-Lipoxygenase Inhibitor, Acts as a Chemopreventive Agent in Intestinal Polyposis, by Modulating Polyp and Systemic Inflammation

    PubMed Central

    Heiferman, Jeffrey R.; Shrivastav, Manisha; Vitello, Dominic; Blatner, Nichole R.; Knab, Lawrence M.; Phillips, Joseph D.; Cheon, Eric C.; Grippo, Paul J.; Khazaie, Khashayarsha; Munshi, Hidayatullah G.; Bentrem, David J.

    2015-01-01

    Purpose Leukotrienes and prostaglandins, products of arachidonic acid metabolism, sustain both systemic and lesion-localized inflammation. Tumor-associated Inflammation can also contribute to the pathogenesis of colon cancer. Patients with inflammatory bowel disease (IBD) have increased risk of developing colon cancer. The levels of 5-lipoxygenase (5-LO), the key enzyme for leukotrienes production, are increased in colon cancer specimens and colonic dysplastic lesions. Here we report that Zileuton, a specific 5-LO inhibitor, can prevent polyp formation by efficiently reducing the tumor-associated and systemic inflammation in APCΔ468 mice. Experimental Design In the current study, we inhibited 5-LO by dietary administration of Zileuton in the APCΔ468 mouse model of polyposis and analyzed the effect of in vivo 5-LO inhibition on tumor-associated and systemic inflammation. Results Zileuton-fed mice developed fewer polyps and displayed marked reduction in systemic and polyp-associated inflammation. Pro-inflammatory cytokines and pro-inflammatory innate and adaptive immunity cells were reduced both in the lesions and systemically. As part of tumor-associated inflammation Leukotriene B4 (LTB4), product of 5-LO activity, is increased focally in human dysplastic lesions. The 5-LO enzymatic activity was reduced in the serum of Zileuton treated polyposis mice. Conclusions This study demonstrates that dietary administration of 5-LO specific inhibitor in the polyposis mouse model decreases polyp burden, and suggests that Zileuton may be a potential chemo-preventive agent in patients that are high-risk of developing colon cancer. PMID:25747113

  4. The Medicinal Timber Canarium patentinervium Miq. (Burseraceae Kunth.) Is an Anti-Inflammatory Bioresource of Dual Inhibitors of Cyclooxygenase (COX) and 5-Lipoxygenase (5-LOX)

    PubMed Central

    Mogana, R.; Teng-Jin, K.; Wiart, C.

    2013-01-01

    The barks and leaves extracts of Canarium patentinervium Miq. (Burseraceae Kunth.) were investigated for cyclooxygenase (COX) and 5-lipoxygenase (LOX) inhibition via in vitro models. The corresponding antioxidative power of the plant extract was also tested via nonenzyme and enzyme in vitro assays. The ethanolic extract of leaves inhibited the enzymatic activity of 5-LOX, COX-1, and COX-2 with IC50 equal to 49.66 ± 0.02 μg/mL, 0.60 ± 0.01 μg/mL, and 1.07 ± 0.01 μg/mL, respectively, with selective COX-2 activity noted in ethanolic extract of barks with COX-1/COX-2 ratio of 1.22. The ethanol extract of barks confronted oxidation in the ABTS, DPPH, and FRAP assay with EC50 values equal to 0.93 ± 0.01 μg/mL, 2.33 ± 0.02 μg/mL, and 67.00 ± 0.32 μg/mL, respectively, while the ethanol extract of leaves confronted oxidation in β-carotene bleaching assay and superoxide dismutase (SOD) assay with EC50 value of 6.04 ± 0.02 μg/mL and IC50 value of 3.05 ± 0.01 μg/mL. The ethanol extract acts as a dual inhibitor of LOX and COX enzymes with potent antioxidant capacity. The clinical significance of these data is quite clear that they support a role for Canarium patentinervium Miq. (Burseraceae Kunth.) as a source of lead compounds in the management of inflammatory diseases. PMID:25937987

  5. Pre-treatment of HT-29 cells with 5-LOX inhibitor (MK-886) induces changes in cell cycle and increases apoptosis after photodynamic therapy with hypericin.

    PubMed

    Kleban, Ján; Szilárdiová, Beáta; Mikes, Jaromír; Horváth, Viktor; Sacková, Veronika; Brezáni, Peter; Hofmanová, Jirina; Kozubík, Alois; Fedorocko, Peter

    2006-08-01

    It may be hypothesized that the lipoxygenase (LOX) metabolic pathway plays an important role in photodynamic therapy (PDT) of malignant tumours, and modification of this pathway may result in administration of lower doses of photodynamic active agents accompanied by reduced side effects. In this study, we examine in more detail the cytokinetic parameters of human colon adenocarcinoma HT-29 cells pre-treated for 48 or 24h with LOX inhibitor MK-886, followed by PDT induced by hypericin. Based on MTT assay the concentrations of both agents (MK-886 and hypericin) with relatively slight (non-significant) cytotoxic effects were selected. These concentrations were used for combined treatment, where MTT response, total cell number, floating cells quantification, viability, cell cycle progression and DNA synthesis were detected. Hoechst/PI staining, PARP fragmentation and mitochondrial membrane potential (MMP) were evaluated to determine the extent of apoptosis. While MK-886 alone caused mainly necrosis, 48h pre-treatment of cells with MK-886 followed by PDT with hypericin clearly shifted the type of cell death to apoptosis. PDT with hypericin alone caused apoptosis in 19% of the cell population. Some combined modalities significantly potentiated the apoptotic effect (31% of apoptotic cells; 2.5microM MK-886/0.1microM hypericin), i.e., by 60% more than after single treatment with hypericin. Increased apoptosis was confirmed by PARP (116kDa) cleavage to characteristic 89kDa fragments and changes in MMP. Increasing concentration of MK-886 was accompanied by massive changes in the cell cycle progression. Combined treatment with lower concentrations of MK-886 and hypericin increased accumulation of cells in the S phase, accompanied by inhibition of DNA synthesis. Increasing concentration of MK-886 in this combination caused the opposite effect, manifesting significant accumulation of cells in the G0/G1 phase. More pronounced effects were observed after the 48h pre

  6. Serum 5-LOX: a progressive protein marker for breast cancer and new approach for therapeutic target.

    PubMed

    Kumar, Rahul; Singh, Abhay Kumar; Kumar, Manoj; Shekhar, Shashank; Rai, Nitish; Kaur, Punit; Parshad, Rajinder; Dey, Sharmistha

    2016-09-01

    Lipoxygenase (LOX) pathway has emerged to have a role in carcinogenesis. There is an evidence that both 12-LOX and 5-LOX have procarcinogenic role. We have previously reported the elevated level of serum 12-LOX in breast cancer patients. This study evaluated the serum level of 5-LOX in breast cancer patients and its in vitro inhibition assessment with peptide inhibitor YWCS. The level of 5-LOX was determined by surface plasmon resonance (SPR). The peptide inhibitor of 5-LOX was designed by molecular modeling and kinetic assay was performed by spectrophotometry. The siRNA mediated 5-LOX gene silencing was performed to investigate the effect on proliferation of MDA-MB-231, breast cancer cell line. The serum 5-LOX level in breast cancer (5.69±1.97ng/µl) was almost 2-fold elevated compared to control (3.53±1.0ng/µl) (P < 0.0001). The peptide YWCS had shown competitive inhibitory effects with IC50, 2.2 µM and dissociation constant (K D), 4.92×10(-8) M. The siRNA mediated knockdown of 5-LOX, resulted in the decreased gene expression for 5-LOX and increased cell death in MDA-MB-231 cell line and thereby play a key role in reducing tumor proliferation. Thus, it can be concluded that 5-LOX is one of the potential serum protein marker for breast cancer and a promising therapeutic target for the same. PMID:27432812

  7. Simultaneous targeting of 5-LOX-COX and EGFR blocks progression of pancreatic ductal adenocarcinoma

    PubMed Central

    Rao, Chinthalapally V.; Janakiram, Naveena B.; Madka, Venkateshwar; Devarkonda, Vishal; Brewer, Misty; Biddick, Laura; Lightfoot, Stan; Steele, Vernon E.; Mohammed, Altaf

    2015-01-01

    Cyclooxygenase-2 (COX-2), 5-Lipoxygenase (5-LOX), and epidermal growth factor receptor (EGRF) are over-expressed in human pancreatic ductal adenocarcinoma (PDAC). Using next-generation sequencing (NGS) analysis, we show significant increase in COX-2, 5-LOX, and EGFR expression during PDAC progression. Targeting complementary pathways will achieve better treatment efficacy than a single agent high-dose strategy that could increase risk of side effects and tumor resistance. To target COX-2, 5-LOX, and EGFR simultaneously, we tested effects of licofelone (dual 5-LOX-COX inhibitor), and gefitinib (EGFR inhibitor), individually and in combination, on pancreatic intraepithelial neoplasms (PanINs) and their progression to PDAC using genetically engineered mice. Individually, licofelone (L) and gefitinib (G) significantly inhibited incidence of PDAC in male (72% L, 90% G, p < 0.0001) and female (90% L, 85% G, p < 0.0001) mice. The combination drug treatment produced complete inhibition of PDAC in both genders. Pancreata of mice receiving combination treatment showed significantly fewer Dclk1-positive cancer stem-like cells, inhibition of COX-2, 5-LOX, PCNA, EGFR and β-catenin expression (p < 0.05–0.0002), increased p21 expression. Significant changes in tumor immune responses and desmoplastic reaction was observed by NGS analysis in combination treatment (p < 0.05). In summary, early simultaneous targeting of 5-LOX-COX- and EGFR pathways may provide additive inhibitory effects leading to complete suppression of PDAC. PMID:26429877

  8. Maximum Time of the Effect of Antileukotriene - Zileuton in Treatment of Patients with Bronchial Asthma

    PubMed Central

    Morina, Naim; Boçari, Gëzim; Iljazi, Ali; Hyseini, Kadir; Halac, Gunay

    2016-01-01

    Objective: Maximum time of the effect of antileukotriene substances - Zileuton in the treatment of patients with bronchial asthma and increased bronchial reactivity and of the salbutamol as agonist of the beta2 adrenergic receptor studied in this work. Methods: Parameters of the lung function are determined with Body plethysmography. Raw and ITGV were registered and specific resistance (SRaw) was calculated. Zileuton (Zyflo, tbl. 600 mg), producer Cornerstone Therapeutics, USA was used in the research. Results: Results of this research, in patients with bronchial asthma, indicate that antileukotriene substances–Zileuton administered in a dose of 600 mg first day (oral route of administration 4 × 1 tbl.) has not caused significant decrease of the specific resistance of the airways (SRaw) (p value 0.1 > Alpha 0.05), whereas Zileuton administered two days in a row, in a dose of 600 mg (4 × 1 tbl. a day), has caused significant decrease of the specific resistance of the airways (SRaw) (P value 0.03 < Alpha 0.05). Effect of the control with salbutamol (beta2-adrenergic receptor agonist) is efficient in the removal of the increased bronchomotor tone, causing significant decrease of the resistance (Raw), respectively of the specific resistance (SRaw), (p value 0.05 = Alpha 0.05). Conclusion: Formation of leukotrienes depends on the lypoxygenation of the arachidonic acid by 5-lypoxygenase. Zileuton is an active and powerful inhibitor of the activity of 5- lypoxygenase and as such inhibits generation of its products. Consequently, besides inhibition of cys-LTs’, zileuton also inhibits the formation of leukotriene B4 (LTB4), which is a powerful chemotactic of other eicosanoids too, which depend on the synthesis of lekotriene A4 (LTA4). This suggests that the effect of antileukotrienes (Zileuton) is not immediate after oral administration, but the powerful effect of the Zileuton seen only after two days of inhibition of cys-LTs’, and inhibition of leukotriene B4 (LTB4

  9. Lipid metabolism enzyme 5-LOX and its metabolite LTB4 are capable of activating transcription factor NF-{kappa}B in hepatoma cells

    SciTech Connect

    Zhao, Yu; Wang, Wenhui; Wang, Qi; Zhang, Xiaodong; Ye, Lihong

    2012-02-24

    Highlights: Black-Right-Pointing-Pointer 5-LOX is able to upregulate expression of NF-{kappa}B p65. Black-Right-Pointing-Pointer 5-LOX enhances nuclear translocation of NF-{kappa}B p65 via increasing p-I{kappa}B-{alpha} level. Black-Right-Pointing-Pointer 5-LOX stimulates transcriptional activity of NF-{kappa}B in hepatoma cells. Black-Right-Pointing-Pointer LTB4 activates transcriptional activity of NF-{kappa}B in hepatoma cells. -- Abstract: The issue that lipid metabolism enzyme and its metabolites regulate transcription factors in cancer cell is not fully understood. In this study, we first report that the lipid metabolism enzyme 5-Lipoxygenase (5-LOX) and its metabolite leukotriene B4 (LTB4) are capable of activating nuclear factor-{kappa}B (NF-{kappa}B) in hepatoma cells. We found that the treatment of MK886 (an inhibitor of 5-LOX) or knockdown of 5-LOX was able to downregulate the expression of NF-{kappa}B p65 at the mRNA level and decreased the phosphorylation level of inhibitor {kappa}B{alpha} (I{kappa}B{alpha}) in the cytoplasm of hepatoma HepG2 or H7402 cells, which resulted in the decrease of the level of nuclear NF-{kappa}B p65. These were confirmed by immunofluorescence staining in HepG2 cell. Moreover, the above treatments were able to decrease the transcriptional activity of NF-{kappa}B in the cells. The LTB4, one of metabolites of 5-LOX, is responsible for 5-LOX-activated NF-{kappa}B in a dose-dependent manner. Thus, we conclude that the lipid metabolism enzyme 5-LOX and its metabolite LTB4 are capable of activating transcription factor NF-{kappa}B in hepatoma cells. Our finding provides new insight into the significance of lipid metabolism in activation of transcription factors in cancer.

  10. Chemoprevention of 7,12-dimethylbenz[a]anthracene (DMBA)-induced Hamster Cheek Pouch Carcinogenesis by a 5-Lipoxygenase Inhibitor, Garcinol

    PubMed Central

    Shim, Joong-Youn; Sang, Shengmin; Sun, Zheng; Chen, Xiaoxin

    2013-01-01

    Our previous studies have shown that aberrant arachidonic acid metabolism, especially the 5-lipoxygenase (5-Lox) pathway, is involved in oral carcinogenesis, and can be targeted for cancer prevention. In order to develop potent topical agents for oral cancer chemoprevention, five known 5-Lox inhibitors from dietary and synthetic sources, Zileuton, ABT-761, Licofelone, Curcumin and Garcinol, were evaluated in silico for their potential efficacy. Garcinol, a polyisoprenylated benzophenone from the fruit rind of Garcinia spp., was found to be a promising agent based on the calculation of a theoretical activity index. Computer modeling showed that garcinol well fit the active site of 5-Lox, and potentially inhibited enzyme activity through interactions between the phenolic hydroxyl groups and the non-heme catalytic iron. In a short-term study on 7,12-dimethylbenz[a]anthracene (DMBA)-treated hamster cheek pouch, topical garcinol suppressed leukotriene B4 (LTB4) biosynthesis and inhibited inflammation and cell proliferation in the oral epithelium. In a long-term carcinogenesis study, topical garcinol significantly reduced the size of visible tumors, the number of cancer lesions, cell proliferation, and LTB4 biosynthesis. These results demonstrated that topical application of a 5-Lox inhibitor, garcinol, had chemopreventive effect on DMBA-induced hamster cheek pouch carcinogenesis. PMID:23137051

  11. Chemoprevention of 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster cheek pouch carcinogenesis by a 5-lipoxygenase inhibitor, garcinol.

    PubMed

    Chen, Xin; Zhang, Xinyan; Lu, Ye; Shim, Joong-Youn; Sang, Shengmin; Sun, Zheng; Chen, Xiaoxin

    2012-01-01

    Our previous studies have shown that aberrant arachidonic acid metabolism, especially the 5-lipoxygenase (5-Lox) pathway, is involved in oral carcinogenesis and can be targeted for cancer prevention. To develop potent topical agents for oral cancer chemoprevention, 5 known 5-Lox inhibitors from dietary and synthetic sources (Zileuton, ABT-761, licofelone, curcumin, and garcinol) were evaluated in silico for their potential efficacy. Garcinol, a polyisoprenylated benzophenone from the fruit rind of Garcinia spp., was found to be a promising agent based on the calculation of a theoretical activity index. Computer modeling showed that garcinol well fit the active site of 5-Lox, and potentially inhibited enzyme activity through interactions between the phenolic hydroxyl groups and the non-heme catalytic iron. In a short-term study on 7,12-dimethylbenz[a]anthracene (DMBA)-treated hamster cheek pouch, topical garcinol suppressed leukotriene B4 (LTB4) biosynthesis and inhibited inflammation and cell proliferation in the oral epithelium. In a long-term carcinogenesis study, topical garcinol significantly reduced the size of visible tumors, the number of cancer lesions, cell proliferation, and LTB4 biosynthesis. These results demonstrated that topical application of a 5-Lox inhibitor, garcinol, had chemopreventive effect on DMBA-induced hamster cheek pouch carcinogenesis. PMID:23137051

  12. Randomized Trial of Zileuton for Treatment of COPD Exacerbations Requiring Hospitalization

    PubMed Central

    Woodruff, Prescott G.; Albert, Richard K.; Bailey, William C.; Casaburi, Richard; Connett, John E.; Cooper, John A. D.; Criner, Gerard J.; Curtis, Jeffrey L.; Dransfield, Mark T.; Han, Meilan K.; Harnden, Sarah M.; Kim, Victor; Marchetti, Nathaniel; Martinez, Fernando J.; McEvoy, Charlene E.; Niewoehner, Dennis E.; Reilly, John J.; Rice, Kathryn; Scanlon, Paul D.; Scharf, Steven M.; Sciurba, Frank C.; Washko, George R.; Lazarus, Stephen C.

    2013-01-01

    Rationale Leukotrienes have been implicated in the pathogenesis of acute exacerbations of COPD, but leukotriene modifiers have not been studied as a possible therapy for exacerbations. Objective We sought to test the safety and efficacy of adding oral zileuton (a 5-lipoxygenase inhibitor) to usual treatment for acute exacerbations of COPD requiring hospitalization. Methods Randomized double-blind, placebo-controlled, parallel group study of zileuton 600 mg orally, 4 times daily versus placebo for 14 days starting within 12 hours of hospital admission for COPD exacerbation. Primary outcome measure was hospital length of stay; secondary outcomes included treatment failure and biomarkers of leukotriene production. Main Findings Sixty subjects were randomized to zileuton and 59 to placebo (the study was stopped short of enrollment goals because of slow recruitment). There was no difference in hospital length of stay (3.75±2.19 vs. 3.86±3.06 days for zileuton vs. placebo, p=0.39) or treatment failure (23% vs. 27% for zileuton vs. placebo, p=0.63) despite a decline in urinary LTE4 levels in the zileuton-treated group as compared to placebo at 24 hours (change in natural log-transformed ng/mg creatinine −1.38± 1.19 vs. 0.14±1.51, p<0.0001) and 72 hours (−1.32±2.08 vs. 0.26±1.93, p<0.006). Adverse events were similar in both groups. Principal Conclusions While oral zileuton during COPD exacerbations that require hospital admission is safe and reduces urinary LTE4 levels, we found no evidence suggesting that this intervention shortened hospital stay, with the limitation that our sample size may have been insufficient to detect a modest but potentially meaningful clinical improvement. PMID:21299475

  13. Zileuton

    MedlinePlus

    ... natural substances that cause swelling, tightening, and mucus production in the airways. ... your doctor and the laboratory. Your doctor will order certain lab tests before and during your treatment. ...

  14. Zileuton

    MedlinePlus

    ... Kaletra), and saquinavir (Invirase); nefazodone; telithromycin (Ketek); and theophylline (Theo-24, Uniphyl). Your doctor may need to ... any of the following symptoms: agitation, aggressive behavior, anxiety, irritability, unusual dreams, hallucinations (seeing things or hearing ...

  15. The effects of multiple dosing with zileuton on antigen-induced responses in sheep.

    PubMed

    Scuri, M; Allegra, L; Abraham, W M

    1998-01-01

    In a previous study, a single dose of zileuton (10 mg/kg, po) given 2 h before antigen challenge, had a minimal effect on the antigen-induced early airway response (EAR), although it was effective in blocking the late airway response (LAR). Because our previous data indicated that 5-lipoxygenase (5-LO) products contribute to the severity of the antigen-induced EAR in these animals, we hypothesized that the lack of effect of zileuton on the EAR may have had to do with inadequate tissue levels. Therefore, in this study, we determined if multiple dosing with zileuton, which theoretically could improve tissue levels, would provide protection against the antigen-induced EAR as well as the LAR. Each sheep was used in each of the three trials (> or = 15 days apart), the order of which was randomized. For trial 1, the sheep were treated with zileuton (10 mg/kg in 0.1% methylcellulose, p.o.) once a day for 4 days; for trials 2, the sheep were treated with zileuton (10 mg/kg, p.o.) for 2 days; and, for trial 3, the animals were treated with vehicle (0.1% methylcellulose) for 4 days as in trial 1. In all trials, antigen challenge followed 1 h after the last treatment. In the placebo trial, antigen challenge resulted in characteristic EAR (407 +/- 102%, increase over baseline) and LAR (335 +/- 75%, increase over baseline). The antigen-induced effects were completely blocked by the 4-day treatment (EAR = 24 +/- 3%; LAR = 17 +/- 3%, P < 0.05 vs. placebo). In the 2-day trial, the immediate increase in R1, after antigen challenge was only partially blocked (EAR = 163 +/- 16%, P < 0.10 vs. placebo and P < 0.05 vs. 4-day trial), but the late response was completely blocked (24 +/- 3%). The protection against the EAR obtained with the 4-day treatment was significantly better (P < 0.05) than that obtained with the 2-day treatment. The results of this study show that multiple dosing with the 5-LO inhibitor, zileuton, provides protection against the antigen-induced EAR as well as LAR

  16. Effects of zileuton and montelukast in mouse experimental spinal cord injury

    PubMed Central

    Genovese, T; Rossi, A; Mazzon, E; Di Paola, R; Muià, C; Caminiti, R; Bramanti, P; Sautebin, L; Cuzzocrea, S

    2007-01-01

    Background and purpose: 5-lipoxygenase (5-LO) is the key enzyme in leukotriene (LT) biosynthesis from arachidonic acid (AA). Here, we examined the role of the 5-LO-product, cysteinyl-LT (Cys-LT), with a 5-LO inhibitor (zileuton) and a Cys-LT, receptor antagonist (montelukast), in the inflammatory response and tissue injury associated with spinal cord injury (SCI). Experimental approach: SCI was induced in mice by the application of vascular clips to the dura via a two-level T6 to T7 laminectomy for 1 min. Cord inflammation was assessed histologically and by measuring inflammatory mediators (ELISA) and apoptosis by annexin V, TUNEL, Fas ligand staining and Bax and Bcl-2 expression (immunohistochemistry and western blots). Motor function in hindlimbs was assessed by a locomotor rating scale, for 10 days after cord injury. Key results: SCI in mice resulted in tissue damage, oedema, neutrophil infiltration, apoptosis, tumour necrosis-α (TNF-α) and cyclooxygenase-2 (COX-2) expression, prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) production, and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in injured tissue. Treatment of the mice with zileuton or montelukast reduced the spinal cord inflammation and tissue injury, neutrophil infiltration, TNF-α, COX-2 and pERK1/2 expression, PGE2 and LTB4 production, and apoptosis. In separate experiments, zileuton or montelukast significantly improved the recovery of limb function over 10 days. Conclusions and implications: Zileuton and montelukast produced a substantial reduction of inflammatory events associated with experimental SCI. Our data underline the important role of 5-LO and Cys-LT in neurotrauma. PMID:18059327

  17. The effect of food on the pharmacokinetics of zileuton.

    PubMed

    Awni, W M; Cavanaugh, J H; Witt, G; Granneman, G R; Dubé, L M

    1995-01-01

    The present study was undertaken to assess the effect of food on the pharmacokinetic parameters of zileuton. In a nonblinded crossover study, 18 healthy male volunteers who had fasted overnight were randomised to receive a single oral dose of zileuton 600mg in the presence or absence of food consisting of a standardised breakfast on the following morning. The mean zileuton peak plasma concentration (Cmax) increased significantly by 27% after food intake, while the mean area under the plasma concentration versus time curve increased by only 1.4%, a difference that was not statistically significant. The mean time to Cmax was unaffected by the presence of food, as were the other pharmacokinetic parameters assessed. Overall, the results suggest that food has a relatively small effect on the rate of zileuton absorption compared with the fasting state, while the bioavailability of the drug appears to be unaffected. Thus, it is concluded that it is appropriate to administer zileuton with or without food. PMID:8620672

  18. Virtual Dual inhibition of COX-2 / 5-LOX enzymes based on binding properties of alpha-amyrins, the anti-inflammatory compound as a promising anti-cancer drug.

    PubMed

    Ranjbar, Mohammad Mehdi; Assadolahi, Vahideh; Yazdani, Mohsen; Nikaein, Donya; Rashidieh, Behnam

    2016-01-01

    Hydro-alcoholic fruit extract of Cordia myxa was considerably effective on curing acute inflammation in mouse model. Previous studies suggested significant anti-inflammatory activities as well as potential anticancer agent of α-amyrins in seeds. Inhibition of Cyclooxygenase-2 (COX-2) and 5-Lipooxygenase (5-LOX) is significant in cancer prevention and therapeutics although this inhibition with chemo-drugs has its own side-effects. It is shown that these enzymes pathways are related to several cancers including colon, breast and lung cancer. This study was conducted based on Cordia species' α-amyrins as a safer natural anti-cancer compound for inhibition of COX-2 and 5-LOX enzymes by molecular docking. The X-ray crystal structure of COX2 / 5-LOX enzymes and α-amyrins was retrieved and energetically minimized respectively. The binding site and surface of enzymes were detected. Docking studies were performed by AutoDock 4.2 using Lamarckian genetic algorithm (LGA). Finally drug likeness, molecular pharmacokinetic properties and toxicity of α-amyrins was calculated. Molecular Docking revealed hydrogen and hydrophobic interactions between α-amyrins with both active sites of COX-2 and 5-LOX enzymes. Interestingly, it covalently bonded to Fe cofactor of 5-LOX enzyme and chelated this molecule. Base on binding energies (∆G) α-amyrin has more inhibitory effects on 5-LOX (-10.45 Kcal/mol) than COX-2 (-8.02 Kcal/mol). Analysis of molecular pharmacokinetic parameters suggested that α-amyrins complied with most sets of Lipinski's rules, and so it could be a suitable ligand for docking studies. Eventually, bioactivity score showed α-amyrins possess considerable biological activities as nuclear receptor, enzyme inhibitor, GPCR and protease inhibitor ligand. These results clearly demonstrate that α-amyrins could act as potential highly selective COX-/5-LOX inhibitor. Also, it is a safe compound in comparison with classical non-steroidal anti-inflammatory drugs (NSAIDs

  19. Virtual Dual inhibition of COX-2 / 5-LOX enzymes based on binding properties of alpha-amyrins, the anti-inflammatory compound as a promising anti-cancer drug

    PubMed Central

    Ranjbar, Mohammad Mehdi; Assadolahi, Vahideh; Yazdani, Mohsen; Nikaein, Donya; Rashidieh, Behnam

    2016-01-01

    Hydro-alcoholic fruit extract of Cordia myxa was considerably effective on curing acute inflammation in mouse model. Previous studies suggested significant anti-inflammatory activities as well as potential anticancer agent of α-amyrins in seeds. Inhibition of Cyclooxygenase-2 (COX-2) and 5-Lipooxygenase (5-LOX) is significant in cancer prevention and therapeutics although this inhibition with chemo-drugs has its own side-effects. It is shown that these enzymes pathways are related to several cancers including colon, breast and lung cancer. This study was conducted based on Cordia species' α-amyrins as a safer natural anti-cancer compound for inhibition of COX-2 and 5-LOX enzymes by molecular docking. The X-ray crystal structure of COX2 / 5-LOX enzymes and α-amyrins was retrieved and energetically minimized respectively. The binding site and surface of enzymes were detected. Docking studies were performed by AutoDock 4.2 using Lamarckian genetic algorithm (LGA). Finally drug likeness, molecular pharmacokinetic properties and toxicity of α-amyrins was calculated. Molecular Docking revealed hydrogen and hydrophobic interactions between α-amyrins with both active sites of COX-2 and 5-LOX enzymes. Interestingly, it covalently bonded to Fe cofactor of 5-LOX enzyme and chelated this molecule. Base on binding energies (∆G) α-amyrin has more inhibitory effects on 5-LOX (-10.45 Kcal/mol) than COX-2 (-8.02 Kcal/mol). Analysis of molecular pharmacokinetic parameters suggested that α-amyrins complied with most sets of Lipinski's rules, and so it could be a suitable ligand for docking studies. Eventually, bioactivity score showed α-amyrins possess considerable biological activities as nuclear receptor, enzyme inhibitor, GPCR and protease inhibitor ligand. These results clearly demonstrate that α-amyrins could act as potential highly selective COX-/5-LOX inhibitor. Also, it is a safe compound in comparison with classical non-steroidal anti-inflammatory drugs (NSAIDs

  20. Zileuton restores memory impairments and reverses amyloid and tau pathology in aged Alzheimer's disease mice.

    PubMed

    Di Meco, Antonio; Lauretti, Elisabetta; Vagnozzi, Alana N; Praticò, Domenico

    2014-11-01

    The enzyme 5-lipoxygenase (5LO) is upregulated in Alzheimer's disease (AD), and its pharmacologic blockade with zileuton slows down the development of the AD-like phenotype in young AD mice. However, its efficacy after the AD pathology is established is unknown. To this end, starting at 12 months of age triple transgenic mice (3xTg) received zileuton, a selective 5LO inhibitor, or placebo for 3 months, and then the effect of this treatment on behavior, amyloid, and tau pathology assessed. Although mice on placebo showed worsening of their memory, treated mice performed even better than at baseline. Compared with placebo, treated mice had significantly less Aβ deposits and tau phosphorylation secondary to reduced γ-secretase and CDK-5 activation, respectively. Our data provide novel insights into the disease-modifying action of pharmacologically inhibiting 5LO as a viable AD therapeutic approach. They represent the successful completion of preclinical studies for the development of this class of drug as clinically applicable therapy for the disease. PMID:24973121

  1. Aspirin and Zileuton and Biomarker Expression in Nasal Tissue of Current Smokers | Division of Cancer Prevention

    Cancer.gov

    This randomized phase II trial studies the effects of aspirin and zileuton on genes related to tobacco use in current smokers. Smokers are at increased risk for developing lung and other cancers. Aspirin and zileuton may interfere with genes related to tobacco use and may be useful in preventing lung cancer in current smokers. |

  2. Synthesis, anti-inflammatory, analgesic, 5-lipoxygenase (5-LOX) inhibition activities, and molecular docking study of 7-substituted coumarin derivatives.

    PubMed

    Srivastava, Pavan; Vyas, Vivek K; Variya, Bhavesh; Patel, Palak; Qureshi, Gulamnizami; Ghate, Manjunath

    2016-08-01

    In the present study, 7-subsituted coumarin derivatives were synthesized using various aromatic and heterocyclic amines, and evaluated in vivo for anti-inflammatory and analgesic activity, and for ulcerogenic risk. The most active compounds were evaluated in vitro for 5-lipoxygenase (5-LOX) inhibition. Docking study was performed to predict the binding affinity, and orientation at the active site of the enzyme. In vivo anti-inflammatory and analgesic activity, and in vitro 5-LOX enzyme inhibition study revealed that compound 33 and 35 are the most potent compounds in all the screening methods. In vitro kinetic study of 35 showed mixed or non-competitive type of inhibition with 5-LOX enzyme. Presence of OCH3 group in 35 and Cl in 33 at C6-position of benzothiazole ring were found very important substitutions for potent activity. PMID:27376460

  3. Simultaneous targeting of 5-LOX-COX and ODC block NNK-induced lung adenoma progression to adenocarcinoma in A/J mice.

    PubMed

    Kumar, Gaurav; Patlolla, Jagan Mohan R; Madka, Venkateshwar; Mohammed, Altaf; Li, Qian; Zhang, Yuting; Biddick, Laura; Singh, Anil; Gillaspy, Allison; Lightfoot, Stanley; Steele, Vernon E; Kopelovich, Levy; Rao, Chinthalapally V

    2016-01-01

    Lung cancer is the leading cause of cancer deaths worldwide. Targeting complementary pathways will achieve better treatment efficacy than a single agent high-dose strategy that could increase risk of side effects and tumor resistance. To target COX-2, 5-LOX, and ODC simultaneously, we tested the effects of a dual 5-LOX-COX inhibitor, licofelone, and an ODC inhibitor, DFMO, alone and in combination, on NNK-induced lung tumors in female A/J mice. Seven-week-old mice were treated with NNK (10 μmol/mouse, single dose, i.p.) and randomized to different treatment groups. Three weeks after injection, mice were fed control or experimental diets (DFMO 1500/3000 ppm, licofelone 200/400 ppm, or a low-dose combination of 1500 ppm DFMO and 200 ppm licofelone) for 17 or 34 weeks. Both agents significantly inhibited tumor formation in a dose-dependent manner. As anticipated more adenomas and adenocarcinomas were observed at 17 and 34 weeks, respectively. Importantly, low dose combination of DFMO and licofelone showed more pronounced effects at 17 or 34 weeks in inhibiting the total tumor formation (~60%, p < 0.0001) and adenocarcinoma (~65%, p < 0.0001) compared to individual high dose of DFMO (~44% and 46%, p < 0.0001) and licofelone (~48% and 55%, p < 0.0001). DFMO and combination-treated mice lung tumors exhibited modulated ODC pathway components (Oat, Oaz, SRM, SMS, and SAT, p < 0.05) along with decreased proliferation (PCNA, Cyclin D1 and Cyclin A) and increased expression of p53, p21 and p27 compared to mice fed control diet. Both DFMO and licofelone significantly inhibited tumor inflammatory markers. Our findings suggest that a low-dose combined treatment targeting inflammation and polyamine synthesis may provide effective chemoprevention. PMID:27293987

  4. Simultaneous targeting of 5-LOX-COX and ODC block NNK-induced lung adenoma progression to adenocarcinoma in A/J mice

    PubMed Central

    Kumar, Gaurav; Patlolla, Jagan Mohan R; Madka, Venkateshwar; Mohammed, Altaf; Li, Qian; Zhang, Yuting; Biddick, Laura; Singh, Anil; Gillaspy, Allison; Lightfoot, Stanley; Steele, Vernon E; Kopelovich, Levy; Rao, Chinthalapally V

    2016-01-01

    Lung cancer is the leading cause of cancer deaths worldwide. Targeting complementary pathways will achieve better treatment efficacy than a single agent high-dose strategy that could increase risk of side effects and tumor resistance. To target COX-2, 5-LOX, and ODC simultaneously, we tested the effects of a dual 5-LOX-COX inhibitor, licofelone, and an ODC inhibitor, DFMO, alone and in combination, on NNK-induced lung tumors in female A/J mice. Seven-week-old mice were treated with NNK (10 μmol/mouse, single dose, i.p.) and randomized to different treatment groups. Three weeks after injection, mice were fed control or experimental diets (DFMO 1500/3000 ppm, licofelone 200/400 ppm, or a low-dose combination of 1500 ppm DFMO and 200 ppm licofelone) for 17 or 34 weeks. Both agents significantly inhibited tumor formation in a dose-dependent manner. As anticipated more adenomas and adenocarcinomas were observed at 17 and 34 weeks, respectively. Importantly, low dose combination of DFMO and licofelone showed more pronounced effects at 17 or 34 weeks in inhibiting the total tumor formation (~60%, p < 0.0001) and adenocarcinoma (~65%, p < 0.0001) compared to individual high dose of DFMO (~44% and 46%, p < 0.0001) and licofelone (~48% and 55%, p < 0.0001). DFMO and combination-treated mice lung tumors exhibited modulated ODC pathway components (Oat, Oaz, SRM, SMS, and SAT, p < 0.05) along with decreased proliferation (PCNA, Cyclin D1 and Cyclin A) and increased expression of p53, p21 and p27 compared to mice fed control diet. Both DFMO and licofelone significantly inhibited tumor inflammatory markers. Our findings suggest that a low-dose combined treatment targeting inflammation and polyamine synthesis may provide effective chemoprevention. PMID:27293987

  5. Enzymatic Studies of Isoflavonoids as Selective and Potent Inhibitors of Human Leukocyte 5-Lipo-Oxygenase.

    PubMed

    Mascayano, Carolina; Espinosa, Victoria; Sepúlveda-Boza, Silvia; Hoobler, Eric K; Perry, Steve; Diaz, Giovanni; Holman, Theodore R

    2015-07-01

    Continuing our search to find more potent and selective 5-LOX inhibitors, we present now the enzymatic evaluation of seventeen isoflavones (IR) and nine isoflavans (HIR), and their in vitro and in cellulo potency against human leukocyte 5-LOX. Of the 26 compounds tested, 10 isoflavones and 9 isoflavans possessed micromolar potency, but only three were selective against 5-LOX (IR-2, HIR-303, and HIR-309), with IC50 values at least 10 times lower than those of 12-LOX, 15-LOX-1, and 15-LOX-2. Of these three, IR-2 (6,7-dihydroxy-4-methoxy-isoflavone, known as texasin) was the most selective 5-LOX inhibitor, with over 80-fold potency difference compared with other isozymes; Steered Molecular Dynamics (SMD) studies supported these findings. The presence of the catechol group on ring A (6,7-dihydroxy versus 7,8-dihydroxy) correlated with their biological activity, but the reduction of ring C, converting the isoflavones to isoflavans, and the substituent positions on ring B did not affect their potency against 5-LOX. Two of the most potent/selective inhibitors (HIR-303 and HIR-309) were reductive inhibitors and were potent against 5-LOX in human whole blood, indicating that isoflavans can be potent and selective inhibitors against human leukocyte 5-LOX in vitro and in cellulo. PMID:25359714

  6. The anti-inflammatory pharmacology of Pycnogenol in humans involves COX-2 and 5-LOX mRNA expression in leukocytes.

    PubMed

    Canali, Raffaella; Comitato, Raffaella; Schonlau, Frank; Virgili, Fabio

    2009-09-01

    We investigated the effects of Pycnogenol supplementation on the arachidonic acid pathway in human polymorphonuclear leukocytes (PMNL) in response to an inflammatory stimulus. Pycnogenol is a standardised extract of French maritime pine bark consisting of procyanidins and polyphenolic monomers. Healthy volunteers aged 35 to 50 years were supplemented with 150 mg Pycnogenol a day for five days. Before and after the final day of supplementation, blood was drawn and PMNL were isolated. PMNL were primed with lipopolysaccharide (LPS) and stimulated with the receptor-mediated agonist formyl-methionyl-leucyl-phenylalanine (fMLP) to activate the arachidonic acid pathway and the biosynthesis of leukotrienes, thromboxane and prostaglandins. Pycnogenol supplementation inhibited 5-lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2) gene expression and phospholipase A2 (PLA2) activity. This effect was associated with a compensatory up-regulation of COX-1 gene expression. Interestingly, Pycnogenol suspended the interdependency between 5-LOX and 5-lipoxygenase activating protein (FLAP) expression. Pycnogenol supplementation reduced leukotriene production but did not leave prostaglandins unaltered, which we attribute to a decline of COX-2 activity in favour of COX-1. Here we show for the first time that Pycnogenol supplementation simultaneously inhibits COX-2 and 5-LOX gene expression and reduces leukotriene biosynthesis in human PMNL upon pro-inflammatory stimulation ex vivo. PMID:19508901

  7. Comparison of oral montelukast with oral zileuton in acute asthma: A randomized, double-blind, placebo-controlled study

    PubMed Central

    Magazine, Rahul; Shahul, Hameed Aboobackar; Chogtu, Bharti; Kamath, Asha

    2016-01-01

    Background: Leukotriene modifiers have an established role in the management of chronic asthma but their role in acute asthma is still under evaluation. Objective: To study and compare the effects of oral montelukast with oral zileuton in acute asthma. Materials and Methods: This study included 120 asthmatics and was conducted from September 2012 to March 2014. Patients were randomized into three different groups to receive montelukast or zileuton or placebo in addition to standard treatment for asthma exacerbation. Peak expiratory flow rate (PEFR) values, details of rescue medication and vital signs were recorded at 6 h, 12 h, 24 h, and 48 h of drug or placebo administration and at discharge. Additional recording was done in the morning (8–10 am) following admission. The primary endpoint was the mean PEFR of each group at these time points; the secondary end point being the need for rescue medications. Results: The mean PEFR recordings of the three study groups – placebo, montelukast, and zileuton – respectively, at various time points were as follows: at 6 h (223.25 ± 90.40, 199.00 ± 82.52, 233.75 ± 84.05; P = 0.240); at 12 h (271.00 ± 109.38, 251.50 ± 101.44, 309.50 ± 129.63; P = 0.048); at 24 h (288.25 ± 114.26, 269.00 ± 107.51, 324.50 ± 127.88; P = 0.080); and at 48 h (295.00 ± 114.80, 293.50 ± 113.24, 344.75 ± 119.91; P = 0.015); discharge (305.00 ± 118.56, 305.25 ± 119.51, 361.25 ± 119.70; P = 0.010). The mean PEFR for the three study groups at 8–10 am on the morning following admission was 268.75 ± 111.43, 252.50 ± 99.99, 306.75 ± 114.44; P = 0.047. Total rescue doses needed were 10, 1, and 0, respectively (P = 0.049). Conclusion: Zileuton is better than montelukast as an additional drug in acute asthma and results in significant improvement in lung function, and reduction in the need for rescue medications. PMID:27185992

  8. A dual inhibitor of cyclooxygenase and 5-lipoxygenase protects against kainic acid-induced brain injury.

    PubMed

    Minutoli, Letteria; Marini, Herbert; Rinaldi, Mariagrazia; Bitto, Alessandra; Irrera, Natasha; Pizzino, Gabriele; Pallio, Giovanni; Calò, Margherita; Adamo, Elena Bianca; Trichilo, Vincenzo; Interdonato, Monica; Galfo, Federica; Squadrito, Francesco; Altavilla, Domenica

    2015-06-01

    Systemic administration of kainic acid causes inflammation and apoptosis in the brain, resulting in neuronal loss. Dual cyclooxygenase/5-lipoxygenase (COX/5-LOX) inhibitors could represent a possible neuroprotective approach in preventing glutamate excitotoxicity. Consequently, we investigated the effects of a dual inhibitor of COX/5-LOX following intraperitoneal administration of kainic acid (KA, 10 mg/kg) in rats. Animals were randomized to receive either the dual inhibitor of COX/5-LOX (flavocoxid, 20 mg/kg i.p.) or its vehicle (1 ml/kg i.p.) 30 min after KA administration. Sham brain injury rats were used as controls. We evaluated protein expression of phosphorylated extracellular signal-regulated kinase (p-ERK1/2) and tumor necrosis factor alpha (TNF-α) as well as levels of malondialdehyde (MDA), prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) in the hippocampus. Animals were also observed for monitoring behavioral changes according to Racine Scale. Finally, histological analysis and brain edema evaluation were carried out. Treatment with the dual inhibitor of COX/5-LOX decreased protein expression of p-ERK1/2 and TNF-α in hippocampus, markedly reduced MDA, LTB4 and PGE2 hippocampal levels, and also ameliorated brain edema. Histological analysis showed a reduction in cell damage in rats treated with the dual inhibitor of COX/5-LOX, particularly in hippocampal subregion CA3c. Moreover, flavocoxid significantly improved behavioral signs following kainic acid administration. Our results suggest that dual inhibition of COX/5-LOX by flavocoxid has neuroprotective effects during kainic acid-induced excitotoxicity. PMID:25893744

  9. Pharmacophore modeling and virtual screening for designing potential 5-lipoxygenase inhibitors.

    PubMed

    Aparoy, P; Kumar Reddy, K; Kalangi, Suresh K; Chandramohan Reddy, T; Reddanna, P

    2010-02-01

    Inhibitors of the 5-Lipoxygenase (5-LOX) pathway have a therapeutic potential in a variety of inflammatory disorders such as asthma. In this study, chemical feature based pharmacophore models of inhibitors of 5-LOX have been developed with the aid of HipHop and HypoGen modules within Catalyst program package. The best quantitative pharmacophore model, Hypo1, which has the highest correlation coefficient (0.97), consists of two hydrogen-bond acceptors, one hydrophobic feature and one ring aromatic feature. Hypo1 was further validated by test set and cross validation method. The application of the model shows great success in predicting the activities of 65 known 5-LOX inhibitors in our test set with a correlation coefficient of 0.85 with a cross validation of 95% confidence level, proving that the model is reliable in identifying structurally diverse compounds for inhibitory activity against 5-LOX. Furthermore, Hypo1 was used as a 3D query for screening Maybridge and NCI databases within catalyst and also drug like compounds obtained from Enamine Ltd, which follow Lipinski's rule of five. The hit compounds were subsequently subjected to filtering by docking and visualization, to identify the potential lead molecules. Finally 5 potential lead compounds, identified in the above process, were evaluated for their inhibitory activities. These studies resulted in the identification of two compounds with potent inhibition of 5-LOX activity with IC(50) of 14 microM and 35 microM, respectively. These studies thus validate the pharmacophore model generated and suggest the usefulness of the model in screening of various small molecule libraries and identification of potential lead compounds for 5-LOX inhibition. PMID:20045317

  10. Discovery of a Novel Dual Fungal CYP51/Human 5-Lipoxygenase Inhibitor: Implications for Anti-Fungal Therapy

    PubMed Central

    Hoobler, Eric K.; Rai, Ganesha; Warrilow, Andrew G. S.; Perry, Steven C.; Smyrniotis, Christopher J.; Jadhav, Ajit; Simeonov, Anton; Parker, Josie E.; Kelly, Diane E.; Maloney, David J.; Kelly, S. L.; Holman, Theodore R.

    2013-01-01

    We report the discovery of a novel dual inhibitor targeting fungal sterol 14α-demethylase (CYP51 or Erg11) and human 5-lipoxygenase (5-LOX) with improved potency against 5-LOX due to its reduction of the iron center by its phenylenediamine core. A series of potent 5-LOX inhibitors containing a phenylenediamine core, were synthesized that exhibit nanomolar potency and >30-fold selectivity against the LOX paralogs, platelet-type 12-human lipoxygenase, reticulocyte 15-human lipoxygenase type-1, and epithelial 15-human lipoxygenase type-2, and >100-fold selectivity against ovine cyclooxygenase-1 and human cyclooxygnease-2. The phenylenediamine core was then translated into the structure of ketoconazole, a highly effective anti-fungal medication for seborrheic dermatitis, to generate a novel compound, ketaminazole. Ketaminazole was found to be a potent dual inhibitor against human 5-LOX (IC50 = 700 nM) and CYP51 (IC50 = 43 nM) in vitro. It was tested in whole blood and found to down-regulate LTB4 synthesis, displaying 45% inhibition at 10 µM. In addition, ketaminazole selectively inhibited yeast CYP51 relative to human CYP51 by 17-fold, which is greater selectivity than that of ketoconazole and could confer a therapeutic advantage. This novel dual anti-fungal/anti-inflammatory inhibitor could potentially have therapeutic uses against fungal infections that have an anti-inflammatory component. PMID:23826084

  11. Regulation of rotenone-induced microglial activation by 5-lipoxygenase and cysteinyl leukotriene receptor 1.

    PubMed

    Zhang, Xiao-Yan; Chen, Lu; Yang, Yi; Xu, Dong-Min; Zhang, Si-Ran; Li, Chen-Tan; Zheng, Wei; Yu, Shu-Ying; Wei, Er-Qing; Zhang, Li-Hui

    2014-07-14

    The 5-lipoxygenase (5-LOX) products cysteinyl leukotrienes (CysLTs) are potent pro-inflammatory mediators. CysLTs mediate their biological actions through activating CysLT receptors (CysLT(1)R and CysLT(2)R). We have recently reported that 5-LOX and CysLT(1)R mediated PC12 cell injury induced by high concentrations of rotenone (0.3-10 μM), which was reduced by the selective 5-LOX inhibitor zileuton and CysLT(1)R antagonist montelukast. The purpose of this study was to examine the regulatory roles of the 5-LOX/CysLT(1)R pathway in microglial activation induced by low concentration rotenone. After mouse microglial BV2 cells were stimulated with rotenone (0.3-3 nM), phagocytosis and release of pro-inflammatory cytokine were assayed as indicators of microglial activation. We found that rotenone (1 and 3 nM) increased BV2 microglial phagocytosis and the release of the pro-inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). Zileuton and montelukast prevented rotenone (3 nM)-induced phagocytosis and cytokine release. Furthermore, rotenone significantly up-regulated 5-LOX expression, induced 5-LOX translocation to the nuclear envelope, and increased the production of CysLTs. These responses were inhibited by zileuton. Rotenone also increased CysLT(1)R expression and induced nuclear translocation of CysLT(1)R. In primary rat microglia, rotenone (10 nM) increased release of IL-1β and TNF-α, whereas zileuton (0.1 μΜ) and montelukast (0.01 μΜ) significantly inhibited this response. These results indicated that 5-LOX and CysLT(1)R might be key regulators of microglial activation induced by low concentration of rotenone. Interference of 5-LOX/CysLT(1)R pathway may be an effective therapeutic strategy for microglial inflammation. PMID:24858057

  12. Inhibitors

    MedlinePlus

    ... Community Counts Blood Safety Inhibitors Articles & Key Findings Free Materials Videos Starting the Conversation Playing it Safe A Look at Hemophilia Joint Range of Motion My Story Links to Other Websites ...

  13. 17β Estradiol Modulates Perfusion Pressure and Expression of 5-LOX and CYP450 4A in the Isolated Kidney of Metabolic Syndrome Female Rats

    PubMed Central

    Zúñiga-Muñoz, A. M.; Guarner Lans, V.; Soria-Castro, E.; Diaz-Diaz, E.; Torrico-Lavayen, R.; Tena-Betancourt, E.; Pérez-Torres, I.

    2015-01-01

    Prevalence of metabolic syndrome and progression of nephropathy depend on sex. We examined a protective effect of estradiol against nephropathy in metabolic syndrome through the modulation of the arachidonic acid metabolism by activating the 5-lipoxygenase and cytochrome p450 4A pathways. 28 female Wistar rats were divided into four groups of seven animals each: control, intact metabolic syndrome, ovariectomized metabolic syndrome, and metabolic syndrome ovariectomized plus estradiol. Blood pressure, body weight, body fat, triglycerides, insulin, HOMA-index, albuminuria, and TNF-α were increased in ovariectomized metabolic syndrome rats (p < 0.001). The perfusion pressure in isolated kidneys of ovariectomized metabolic syndrome rats in presence of 4 μg of arachidonic acid was increased. The inhibitors of the arachidonic acid metabolism Baicalein, Miconazole, and Indomethacin in these rats decreased the perfusion pressure by 57.62%, 99.83%, and 108.5%, respectively and they decreased creatinine clearance and the arachidonic acid percentage. Phospholipase A2 expression in the kidney of ovariectomized metabolic syndrome rats was not modified. 5-lipoxygenase was increased in metabolic syndrome ovariectomized rats while cytochrome p450 4A was decreased. In conclusion, the loss of estradiol increases renal damage while the treatment with estradiol benefits renal function by modulating arachidonic acid metabolism through the 5-lipoxygenase and cytochrome p450 4A pathways. PMID:26491436

  14. Effects of MK-886, a 5-lipoxygenase activating protein (FLAP) inhibitor, and 5-lipoxygenase deficiency on the forced swimming behavior of mice.

    PubMed

    Uz, Tolga; Dimitrijevic, Nikola; Imbesi, Marta; Manev, Hari; Manev, Radmila

    2008-05-01

    A common biological pathway may contribute to the comorbidity of atherosclerosis and depression. Increased activity of the enzymatic 5-lipoxygenase (5-LOX, 5LO) pathway is a contributing factor in atherosclerosis and a 5-LOX inhibitor, MK-886, is beneficial in animal models of atherosclerosis. In the brain, MK-886 increases phosphorylation of the glutamate receptor subunit GluR1, and the increased phosphorylation of this receptor has been associated with antidepressant treatment. In this work, we evaluated the behavioral effects of MK-886 in an automated assay of mouse forced swimming, which identifies antidepressant activity as increased climbing behavior and/or decreased rest time. Whereas a single injection of MK-886 (3 and 10 mg/kg) did not affect forced swimming behaviors assayed 30 min later, six daily injections of 3 mg/kg MK-886 slightly increased climbing and significantly reduced rest time in wild-type mice but not in 5-LOX-deficient mice. A diet delivery of MK-886, 4 micro/(100 mg(body-weight)day), required 3 weeks to affect forced swimming; it increased climbing behavior. Climbing behavior was also increased in naive 5-LOX-deficient mice compared to naive wild-type controls. These results suggest that 5-LOX inhibition and deficiency may be associated with antidepressant activity. Increased climbing in a forced swimming assay is a typical outcome of antidepressants that increase noradrenergic and dopaminergic activity. Interestingly, 5-LOX deficiency and MK-886 treatment have been shown to be capable of increasing the behavioral effects of a noradrenaline/dopamine-potentiating drug, cocaine. Future research is needed to evaluate the clinical relevance of our findings. PMID:18403121

  15. Structural optimization and biological evaluation of 1,5-disubstituted pyrazole-3-carboxamines as potent inhibitors of human 5-lipoxygenase

    PubMed Central

    Zhou, Yu; Liu, Jun; Zheng, Mingyue; Zheng, Shuli; Jiang, Chunyi; Zhou, Xiaomei; Zhang, Dong; Zhao, Jihui; Ye, Deju; Zheng, Mingfang; Jiang, Hualiang; Liu, Dongxiang; Cheng, Jian; Liu, Hong

    2016-01-01

    Human 5-lipoxygenase (5-LOX) is a well-validated drug target and its inhibitors are potential drugs for treating leukotriene-related disorders. Our previous work on structural optimization of the hit compound 2 from our in-house collection identified two lead compounds, 3a and 3b, exhibiting a potent inhibitory profile against 5-LOX with IC50 values less than 1 µmol/L in cell-based assays. Here, we further optimized these compounds to prepare a class of novel pyrazole derivatives by opening the fused-ring system. Several new compounds exhibited more potent inhibitory activity than the lead compounds against 5-LOX. In particular, compound 4e not only suppressed lipopolysaccharide-induced inflammation in brain inflammatory cells and protected neurons from oxidative toxicity, but also significantly decreased infarct damage in a mouse model of cerebral ischemia. Molecular docking analysis further confirmed the consistency of our theoretical results and experimental data. In conclusion, the excellent in vitro and in vivo inhibitory activities of these compounds against 5-LOX suggested that these novel chemical structures have a promising therapeutic potential to treat leukotriene-related disorders. PMID:26904397

  16. MK591, a second generation leukotriene biosynthesis inhibitor, prevents invasion and induces apoptosis in the bone-invading C4-2B human prostate cancer cells: implications for the treatment of castration-resistant, bone-metastatic prostate cancer.

    PubMed

    Sarveswaran, Sivalokanathan; Ghosh, Ritisha; Morisetty, Shravan; Ghosh, Jagadananda

    2015-01-01

    Castration-resistant prostate cancer (CRPC) is a major clinical challenge for which no cure is currently available primarily because of the lack of proper understanding about appropriate molecular target(s). Previously we observed that inhibition of 5-lipoxygenase (5-Lox) activity induces apoptosis in some types of prostate cancer cells, suggesting an important role of 5-Lox in the viability of prostate cancer cells. However, nothing is known about the role of 5-Lox in the survival of castration-resistant, metastatic prostate cancer cells. Thus, we tested the effects of MK591, a second-generation, specific inhibitor of 5-Lox activity, on the viability and metastatic characteristics of CRPC cells. We observed that MK591 effectively kills the bone-invading C4-2B human prostate cancer cells (which bear characteristics of CRPC), but does not affect normal, non-cancer fibroblasts (which do not express 5-Lox) in the same experimental conditions. We also observed that MK591 dramatically inhibits the in vitro invasion and soft-agar colony formation of C4-2B cells. Interestingly, we found that treatment with MK591 dramatically down-regulates the expression of c-Myc and its targets at sub-lethal doses. In light of frequent over-activation of c-Myc in a spectrum of aggressive cancers (including CRPC), and the challenges associated with inhibition of c-Myc (because of its non-enzymatic nature), our novel findings of selective killing, and blockade of invasive and soft-agar colony-forming abilities of the castration-resistant, bone-metastatic C4-2B prostate cancer cells by MK591, open up a new avenue to attack CRPC cells for better management of advanced prostate cancer while sparing normal, non-cancer body cells. PMID:25875826

  17. Design, Synthesis, and Biological Evaluation of Some Novel Pyrrolizine Derivatives as COX Inhibitors with Anti-Inflammatory/Analgesic Activities and Low Ulcerogenic Liability.

    PubMed

    Gouda, Ahmed M; Ali, Hamed I; Almalki, Waleed H; Azim, Mohamed A; Abourehab, Mohammed A S; Abdelazeem, Ahmed H

    2016-01-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) are the most commonly prescribed anti-inflammatory and pain relief medications. However, their use is associated with many drawbacks, including mainly serious gastric and renal complications. In an attempt to circumvent these risks, a set of N-(4-bromophenyl)-7-cyano-6-substituted-H-pyrrolizine-5-carboxamide derivatives were designed, synthesized and evaluated as dual COX/5-LOX inhibitors. The structural elucidation, in vivo anti-inflammatory and analgesic activities using a carrageenan-induced rat paw edema model and hot plate assay, were performed, respectively. From the results obtained, it was found that the newly synthesized pyrrolizines exhibited IC50 values in the range of 2.45-5.69 µM and 0.85-3.44 µM for COX-1 and COX-2, respectively. Interestingly, compounds 12, 13, 16 and 17 showed higher anti-inflammatory and analgesic activities compared to ibuprofen. Among these derivatives, compounds 16 and 19 displayed better safety profile than ibuprofen in acute ulcerogenicity and histopathological studies. Furthermore, the docking studies revealed that compound 17 fits nicely into COX-1 and COX-2 binding sites with the highest binding affinity, while compound 16 exerted the highest binding affinity for 5-LOX. In light of these findings, these novel pyrrolizine-5-carboxamide derivatives represent a promising scaffold for further development into potential dual COX/5-LOX inhibitors with safer gastric profile. PMID:26867188

  18. Active site characterization and structure based 3D-QSAR studies on non-redox type 5-lipoxygenase inhibitors.

    PubMed

    Ul-Haq, Zaheer; Khan, Naveed; Zafar, Syed Kashif; Moin, Syed Tarique

    2016-06-10

    Structure-based 3D-QSAR study was performed on a class of 5-benzylidene-2-phenylthiazolinones non-redox type 5-LOX inhibitors. In this study, binding pocket of 5-Lipoxygenase (pdb id 3o8y) was identified by manual docking using 15-LOX (pdb id 2p0m) as a reference structure. Additionally, most of the binding site residues were found conserved in both structures. These non-redox inhibitors were then docked into the binding site of 5-LOX. To generate reliable CoMFA and CoMSIA models, atom fit data base alignment method using docked conformation of the most active compound was employed. The q(2)cv and r(2)ncv values for CoMFA model were found to be 0.549 and 0.702, respectively. The q(2)cv and r(2)ncv values for the selected CoMSIA model comprised four descriptors steric, electrostatic, hydrophobic and hydrogen bond donor fields were found to be 0.535 and 0.951, respectively. Obtained results showed that our generated model was statistically reliable. Furthermore, an external test set validates the reliability of the predicted model by calculating r(2)pred i.e.0.787 and 0.571 for CoMFA and CoMSIA model, respectively. 3D contour maps generated from CoMFA and CoMSIA models were utilized to determine the key structural features of ligands responsible for biological activities. The applied protocol will be helpful to design more potent and selective inhibitors of 5-LOX. PMID:27044904

  19. Novel di-tertiary-butyl phenylhydrazones as dual cyclooxygenase-2/5-lipoxygenase inhibitors: synthesis, COX/LOX inhibition, molecular modeling, and insights into their cytotoxicities.

    PubMed

    Ghatak, Shibnath; Vyas, Alok; Misra, Suniti; O'Brien, Paul; Zambre, Ajit; Fresco, Victor M; Markwald, Roger R; Swamy, K Venkateshwara; Afrasiabi, Zahra; Choudhury, Amitava; Khetmalas, Madhukar; Padhye, Subhash

    2014-01-01

    Although dual inhibition of Cyclooxygenase-2 (COX-2) and 5-Lipoxygenase (5-LOX) enzymes is highly effective than targeting COX or LOX alone, there are only a few reports of examining such compounds in case of colorectal cancers (CRC). In the present work we report that the novel di-tert-butyl phenol-based dual inhibitors DTPSAL, DTPBHZ, DTPINH, and DTPNHZ exhibit significant cytotoxicity against human CRC cell lines. Molecular docking studies revealed a good fit of these compounds in the COX-2 and 5-LOX protein cavities. The inhibitors show significant inhibition of COX-2 and 5-LOX activities and are effective against a panel of human colon cancer cell lines including HCA-7, HT-29, SW480 and intestinal Apc10.1 cells as well as the hyaluronan synthase-2 (Has2) enzyme over-expressing colon cancer cells, through inhibition of the Hyaluronan/CD44v6 cell survival pathway. Western blot analysis and qRT-PCR analyses indicated that the di-tert-butyl phenol-based dual inhibitors reduce the expression of COX-2, 5-LOX, and CD44v6 in human colon cancer HCA-7 cells, while the combination of CD44v6shRNA and DTPSAL has an additional inhibitory effect on CD44v6 mRNA expression. The synergistic inhibitory effect of Celecoxib and Licofelone on CD44v6 mRNA expression suggests that the present dual inhibitors down-regulate cyclooxygenase and lipoxygenase enzymes through CD44v6. The compounds also exhibited enhanced antiproliferative potency compared to standard dual COX/LOX inhibitor, viz. Licofelone. Importantly, the HA/CD44v6 antagonist CD44v6shRNA in combination with synthetic compounds had a sensitizing effect on the cancer cells which enhanced their antiproliferative potency, a finding which is crucial for the anti-proliferative potency of the novel synthetic di-tert-butyl phenol based dual COX-LOX inhibitors in colon cancer cells. PMID:24295787

  20. Suppression of leukotriene B4 generation by ex-vivo neutrophils isolated from asthma patients on dietary supplementation with gammalinolenic acid-containing borage oil: possible implication in asthma.

    PubMed

    Ziboh, Vincent A; Naguwa, Stanley; Vang, Kao; Wineinger, Julie; Morrissey, Brian M; Watnik, Mitchell; Gershwin, M Eric

    2004-03-01

    Dietary gammalinolenic acid (GLA), a potent inhibitor of 5-lipoxygenase (5-LOX) and suppressor of leukotriene B4 (LTB4), can attenuate the clinical course of rheumatoid arthritics, with negligible side effects. Since Zileuton, also an inhibitor of 5-LOX, attenuates asthma but with an undesirable side effect, we investigated whether dietary GLA would suppress biosynthesis of PMN-LTB4 isolated from asthma patients and attenuate asthma. Twenty-four mild-moderate asthma patients (16-75 years) were randomized to receive either 2.0 g daily GLA (borage oil) or corn oil (placebo) for 12 months. Blood drawn at 3 months intervals was used to prepare sera for fatty acid analysis, PMNs for determining phospholipid fatty acids and for LTB4 generation. Patients were monitored by daily asthma scores, pulmonary function, and exhaled NO. Ingestion of daily GLA (i) increased DGLA (GLA metabolite) in PMN-phospholipids; (ii) increased generation of PMN-15-HETrE (5-LOX metabolite of DGLA). Increased PMN-DGLA/15-HETrE paralleled the decreased PMN generation of proinflammatory LTB4. However, the suppression of PMN-LTB4 did not reveal statistically significant suppression of the asthma scores evaluated. Nonetheless, the study demonstrated dietary fatty acid modulation of endogenous inflammatory mediators without side effects and thus warrant further explorations into the roles of GLA at higher doses, leukotrienes and asthma. PMID:15154607

  1. PSEUDOPEROXIDASE INVESTIGATIONS OF HYDROPEROXIDES AND INHIBITORS WITH HUMAN LIPOXYGENASES

    PubMed Central

    Hoobler, Eric K.; Holz, Charles; Holman, Theodore R.

    2013-01-01

    Understanding the mode of action for lipoxygenase (LOX) inhibitors is critical to determining their efficacy in the cell. The pseudoperoxidase assay is an important tool for establishing if a LOX inhibitor is reductive in nature, however, there have been difficulties identifying the proper conditions for each of the many human LOX isozymes. In the current paper, both the 234 nm decomposition (UV) and iron-xylenol orange (XO) assays are shown to be effective methods of detecting pseudoperoxidase activity for 5-LOX, 12-LOX, 15-LOX-1 and 15-LOX-2, but only if 13-(S)-HPODE is used as the hydroperoxide substrate. The AA products, 12-(S)-HPETE and 15-(S)-HPETE, are not consistent hydroperoxide substrates since they undergo a competing transformation to the di-HETE products. Utilizing the above conditions, the selective 12-LOX and 15-LOX-1 inhibitors, probes for diabetes, stroke and asthma, are characterized for their inhibitory nature. Interestingly, ascorbic acid also supports the pseudoperoxidase assay, suggesting that it may have a role in maintaining the inactive ferrous form of LOX in the cell. In addition, it is observed that nordihydroguaiaretic acid (NDGA), a known reductive LOX inhibitor, appears to generate radical species during the pseudoperoxidase assay, which are potent inhibitors against the human LOX isozymes, producing a negative pseudoperoxidase result. Therefore, inhibitors that do not support the pseudoperoxidase assay with the human LOX isozymes, should also be investigated for rapid inactivation, to clarify the negative pseudoperoxidase result. PMID:23669189

  2. Design, synthesis and evaluation of semi-synthetic triazole-containing caffeic acid analogues as 5-lipoxygenase inhibitors.

    PubMed

    De Lucia, Daniela; Lucio, Oscar Méndez; Musio, Biagia; Bender, Andreas; Listing, Monika; Dennhardt, Sophie; Koeberle, Andreas; Garscha, Ulrike; Rizzo, Roberta; Manfredini, Stefano; Werz, Oliver; Ley, Steven V

    2015-08-28

    In this work the synthesis, structure-activity relationship (SAR) and biological evaluation of a novel series of triazole-containing 5-lipoxygenase (5-LO) inhibitors are described. The use of structure-guided drug design techniques provided compounds that demonstrated excellent 5-LO inhibition with IC50 of 0.2 and 3.2 μm in cell-based and cell-free assays, respectively. Optimization of binding and functional potencies resulted in the identification of compound 13d, which showed an enhanced activity compared to the parent bioactive compound caffeic acid 5 and the clinically approved zileuton 3. Compounds 15 and 16 were identified as lead compounds in inhibiting 5-LO products formation in neutrophils. Their interference with other targets on the arachidonic acid pathway was also assessed. Cytotoxicity tests were performed to exclude a relationship between cytotoxicity and the increased activity observed after structure optimization. PMID:26197161

  3. Membrane and inhibitor interactions of intracellular phospholipases A2.

    PubMed

    Mouchlis, Varnavas D; Dennis, Edward A

    2016-05-01

    Studying phospholipases A2 (PLA2s) is a challenging task since they act on membrane-like aggregated substrates and not on monomeric phospholipids. Multidisciplinary approaches that include hydrogen/deuterium exchange mass spectrometry (DXMS) and computational techniques have been employed with great success in order to address important questions about the mode of interactions of PLA2 enzymes with membranes, phospholipid substrates and inhibitors. Understanding the interactions of PLA2s is crucial since these enzymes are the upstream regulators of the eicosanoid pathway liberating free arachidonic acid (AA) and other polyunsaturated fatty acids (PUFA). The liberation of AA by PLA2 enzymes sets off a cascade of molecular events that involves downstream regulators such as cyclooxygenase (COX) and lipoxygenase (LOX) metabolites leading to inflammation. Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) work by inhibiting COX, while Zileuton inhibits LOX and both rely on PLA2 enzymes to provide them with AA. That means PLA2 enzymes can potentially also be targeted to diminish inflammation at an earlier point in the process. In this review we describe extensive efforts reported in the past to define the interactions of PLA2 enzymes with membranes, substrate phospholipids and inhibitors using DXMS, molecular docking, and molecular dynamics (MD) simulations. PMID:26774606

  4. Proteasome inhibitors.

    PubMed

    Teicher, Beverly A; Tomaszewski, Joseph E

    2015-07-01

    Proteasome inhibitors have a 20 year history in cancer therapy. The first proteasome inhibitor, bortezomib (Velcade, PS-341), a break-through multiple myeloma treatment, moved rapidly through development from bench in 1994 to first approval in 2003. Bortezomib is a reversible boronic acid inhibitor of the chymotrypsin-like activity of the proteasome. Next generation proteasome inhibitors include carfilzomib and oprozomib which are irreversible epoxyketone proteasome inhibitors; and ixazomib and delanzomib which are reversible boronic acid proteasome inhibitors. Two proteasome inhibitors, bortezomib and carfilzomib are FDA approved drugs and ixazomib and oprozomib are in late stage clinical trials. All of the agents are potent cytotoxics. The disease focus for all the proteasome inhibitors is multiple myeloma. This focus arose from clinical observations made in bortezomib early clinical trials. Later preclinical studies confirmed that multiple myeloma cells were indeed more sensitive to proteasome inhibitors than other tumor cell types. The discovery and development of the proteasome inhibitor class of anticancer agents has progressed through a classic route of serendipity and scientific investigation. These agents are continuing to have a major impact in their treatment of hematologic malignancies and are beginning to be explored as potential treatment agent for non-cancer indications. PMID:25935605

  5. The regulation of human MMP-13 by licofelone, an inhibitor of cyclo-oxygenases and 5-lipoxygenase, in human osteoarthritic chondrocytes is mediated by the inhibition of the p38 MAP kinase signalling pathway

    PubMed Central

    Boileau, C; Pelletier, J; Tardif, G; Fahmi, H; Laufer, S; Lavigne, M; Martel-Pelletier, J

    2005-01-01

    Background: MMP-13 is one of the most important metalloproteases (MMP) involved in osteoarthritis. Licofelone, a novel dual inhibitor of cyclo-oxygenases (COX) and 5-lipoxygenase (5-LOX), can modulate MMP-13 production in human osteoarthritis chondrocytes. Objective: To evaluate the impact of licofelone on MMP-13 expression/production, promoter, and major MAP kinase signalling pathways and transcription factors. Methods: Human osteoarthritis chondrocytes were stimulated by interleukin 1ß (IL1ß) and treated with or without: licofelone (0.3, 1, or 3 µg/ml); NS-398 (10 µM; a specific COX-2 inhibitor); or BayX-1005 (10 µM; a specific 5-LOX inhibitor). MMP-13 synthesis was determined by specific enzyme linked immunosorbent assay, and expression by real time polymerase chain reaction. The effect of licofelone on the MMP-13 promoter was studied through transient transfection; dexamethasone (10–7 M) was used as comparison. The effect on IL1ß induced MMP-13 signalling pathways was determined using specific ELISA for phosphorylated MAP kinases and transcription factors. Results: Licofelone dose dependently inhibited the IL1ß stimulated production and expression of MMP-13. NS-398 and BayX-1005 had very little effect. Licofelone also inhibited MMP-13 transcription on each of the promoter constructs used. The licofelone inhibition was comparable to that obtained with dexamethasone. Licofelone had no effect on phosphorylated p44/42 or JNK1/2; however, it decreased phosphorylated c-jun and inhibited phosphorylated p38, CREB, and AP-1 activity. Conclusions: Licofelone inhibited MMP-13 production under proinflammatory conditions on human osteoarthritis chondrocytes, through inhibition of the p38/AP-1 pathway and the transcription factor CREB. This may explain some of the mechanisms whereby licofelone exerts its positive effect on osteoarthritic changes. PMID:15498796

  6. Rational Development of a Potent 15-Lipoxygenase-1 Inhibitor with in Vitro and ex Vivo Anti-inflammatory Properties.

    PubMed

    Eleftheriadis, Nikolaos; Neochoritis, Constantinos G; Leus, Niek G J; van der Wouden, Petra E; Dömling, Alexander; Dekker, Frank J

    2015-10-01

    Human 15-lipoxygenase-1 (h-15-LOX-1) is a mammalian lipoxygenase and plays an important role in several inflammatory lung diseases such as asthma, COPD, and chronic bronchitis. Novel potent inhibitors of h-15-LOX-1 are required to explore the role of this enzyme further and to enable drug discovery efforts. In this study, we applied an approach in which we screened a fragment collection that is focused on a diverse substitution pattern of nitrogen-containing heterocycles such as indoles, quinolones, pyrazoles, and others. We denoted this approach substitution-oriented fragment screening (SOS) because it focuses on the identification of novel substitution patterns rather than on novel scaffolds. This approach enabled the identification of hits with good potency and clear structure-activity relationships (SAR) for h-1-5-LOX-1 inhibition. Molecular modeling enabled the rationalization of the observed SAR and supported structure-based design for further optimization to obtain inhibitor 14 d that binds with a Ki of 36 nM to the enzyme. In vitro and ex vivo biological evaluations of our best inhibitor demonstrate a significant increase of interleukin-10 (IL-10) gene expression, which indicates its anti-inflammatory properties. PMID:26331552

  7. Rational development of a potent 15-lipoxygenase-1 inhibitor with in vitro and ex vivo anti-inflammatory properties

    PubMed Central

    Eleftheriadis, Nikolaos; Neochoritis, Constantinos G.; Leus, Niek G.J.; van der Wouden, Petra E.; Dömling, Alexander; Dekker, Frank J.

    2016-01-01

    Human 15-lipoxygenase-1 (h-15-LOX-1) is an important mammalian lipoxygenase and plays an important role in several inflammatory lung diseases such as asthma, COPD and chronic bronchitis. Novel potent inhibitors of h-15-LOX-1 are required to explore the role of this enzyme further and to enable drug discovery efforts. In this study, we applied an approach in which we screened a fragment collection that is focused on a diverse substitution pattern of nitrogen containing heterocycles such as indoles, quinolones, pyrazoles etc. We denoted this approach Substitution Oriented fragment Screening (SOS), because it is focuses on identification of novel substitution patterns rather than on novel scaffolds. This approach enabled the identification of hits with good potency and clear structure activity relationships (SAR) for h-1-5-LOX-1 inhibition. A molecular modeling enabled the rationalization of the observed SAR and supported structure-based design for further optimization to obtain inhibitor 14d that binds with a Ki of 36 nM to the enzyme. In vitro and ex vivo biological evaluations of our best inhibitor demonstrate significant increase of interleukin-10 (IL-10) gene expression, which indicates anti-inflammatory properties. PMID:26331552

  8. Virtual screening using the ligand ZINC database for novel lipoxygenase-3 inhibitors

    PubMed Central

    Monika; Kour, Janmeet; Singh, Kulwinder

    2013-01-01

    The leukotrienes constitute a group of arachidonic acid-derived compounds with biologic activities suggesting important roles in inflammation and immediate hypersensitivity. Epidermis-type lipoxygenase-3 (ALOXE3), a distinct subclass within the multigene family of mammalian lipoxygenases, is a novel isoenzyme involved in the metabolism of leukotrienes and plays a very important role in skin barrier functions. Lipoxygenase selective inhibitors such as azelastine and zileuton are currently used to reduce inflammatory response. Nausea, pharyngolaryngeal pain, headache, nasal burning and somnolence are the most frequently reported adverse effects of these drugs. Therefore, there is still a need to develop more potent lipoxygenase inhibitors. In this paper, we report the screening of various compounds from the ZINC database (contains over 21 million compounds) using the Molegro Virtual Docker software against the ALOXE3 protein. Screening was performed using molecular constraints tool to filter compounds with physico-chemical properties similar to the 1N8Q bound ligand protocatechuic acid. The analysis resulted in 4319 Lipinski compliant hits which are docked and scored to identify structurally novel ligands that make similar interactions to those of known ligands or may have different interactions with other parts of the binding site. Our screening approach identified four molecules ZINC84299674; ZINC76643455; ZINC84299122 & ZINC75626957 with MolDock score of -128.901, -120.22, -116.873 & - 102.116 kcal/mol, respectively. Their energy scores were better than the 1N8Q bound co-crystallized ligand protocatechuic acid (with MolDock score of -77.225 kcal/mol). All the ligands were docked within the binding pocket forming interactions with amino acid residues. PMID:23888100

  9. CFTR Inhibitors

    PubMed Central

    Verkman, Alan S.; Synder, David; Tradtrantip, Lukmanee; Thiagarajah, Jay R.; Anderson, Marc O.

    2014-01-01

    The cystic fibrosis transmembrane conductance regulator (CFTR) protein is a cAMP-regulated Cl− channel whose major function is to facilitate epithelial fluid secretion. Loss-of-function mutations in CFTR cause the genetic disease cystic fibrosis. CFTR is required for transepithelial fluid transport in certain secretory diarrheas, such as cholera, and for cyst expansion in autosomal dominant polycystic kidney disease. High-throughput screening has yielded CFTR inhibitors of the thiazolidinone, glycine hydrazide and quinoxalinedione chemical classes. The glycine hydrazides target the extracellular CFTR pore, whereas the thiazolidinones and quinoxalinediones act at the cytoplasmic surface. These inhibitors have been widely used in cystic fibrosis research to study CFTR function at the cell and organ levels. The most potent CFTR inhibitor has IC50 of approximately 4 nM. Studies in animal models support the development of CFTR inhibitors for antisecretory therapy of enterotoxin-mediated diarrheas and polycystic kidney disease. PMID:23331030

  10. 5-Lipoxygenase metabolite 4-HDHA is a mediator of the antiangiogenic effect of ω-3 polyunsaturated fatty acids.

    PubMed

    Sapieha, Przemyslaw; Stahl, Andreas; Chen, Jing; Seaward, Molly R; Willett, Keirnan L; Krah, Nathan M; Dennison, Roberta J; Connor, Kip M; Aderman, Christopher M; Liclican, Elvira; Carughi, Arianna; Perelman, Dalia; Kanaoka, Yoshihide; Sangiovanni, John Paul; Gronert, Karsten; Smith, Lois E H

    2011-02-01

    Lipid signaling is dysregulated in many diseases with vascular pathology, including cancer, diabetic retinopathy, retinopathy of prematurity, and age-related macular degeneration. We have previously demonstrated that diets enriched in ω-3 polyunsaturated fatty acids (PUFAs) effectively reduce pathological retinal neovascularization in a mouse model of oxygen-induced retinopathy, in part through metabolic products that suppress microglial-derived tumor necrosis factor-α. To better understand the protective effects of ω-3 PUFAs, we examined the relative importance of major lipid metabolic pathways and their products in contributing to this effect. ω-3 PUFA diets were fed to four lines of mice deficient in each key lipid-processing enzyme (cyclooxygenase 1 or 2, or lipoxygenase 5 or 12/15), retinopathy was induced by oxygen exposure; only loss of 5-lipoxygenase (5-LOX) abrogated the protection against retinopathy of dietary ω-3 PUFAs. This protective effect was due to 5-LOX oxidation of the ω-3 PUFA lipid docosahexaenoic acid to 4-hydroxy-docosahexaenoic acid (4-HDHA). 4-HDHA directly inhibited endothelial cell proliferation and sprouting angiogenesis via peroxisome proliferator-activated receptor γ (PPARγ), independent of 4-HDHA's anti-inflammatory effects. Our study suggests that ω-3 PUFAs may be profitably used as an alternative or supplement to current anti-vascular endothelial growth factor (VEGF) treatment for proliferative retinopathy and points to the therapeutic potential of ω-3 PUFAs and metabolites in other diseases of vasoproliferation. It also suggests that cyclooxygenase inhibitors such as aspirin and ibuprofen (but not lipoxygenase inhibitors such as zileuton) might be used without losing the beneficial effect of dietary ω-3 PUFA. PMID:21307302

  11. Isoorientin, a Selective Inhibitor of Cyclooxygenase-2 (COX-2) from the Tubers of Pueraria tuberosa.

    PubMed

    Sumalatha, Manne; Munikishore, Rachakunta; Rammohan, Aluru; Gunasekar, Duvvuru; Kumar, Kotha Anil; Reddy, Kakularam Kumar; Azad, Rajaram; Reddanna, Pallu; Bodo, Bernard

    2015-10-01

    Bioassay-guided fraction of the methanol extract of the roots of Pueraria tuberose DC yielded puerarin, an isoflavone C-glycoside (PT-1), isoorientin, a flavone C-glycoside (PT-2) and mangiferin, a xanthone C-glycoside (PT-3). The extracts and the isolated compounds were screened for potent anti-inflammatory components inhibiting the cyclooxygenases (COX-1 and COX-2) and 5-lipoxygenase (5-LOX), the target enzymes of inflammation, by employing spectroscopic/polorographic methods. Among these, isoorientin was found to be a potent inhibitor of COX-2with an IC50 value of 39 μM. Docking studies were carried out to understand the interactions of isorientin (PT-2) with COX-2.The structures of the isolates were determined by mass spectrometry and 2D-NMR techniques including HSQC, HMBC, NOESY and 1H-1H COSY experiments. Although isoorientin and mangiferin have been reported from several plant sources, this is the first report of their isolation from a Pueraria species. PMID:26669106

  12. [Cyclooxygenases inhibitors and other compounds with antiinflammatory potential in osteoarthrosis--part II].

    PubMed

    Dzielska-Olczak, Małgorzata

    2011-01-01

    NO-NSAIDs (or CINODs that is COX-inhibiting nitric oxide donors) are new class of antiinflammatory drugs and have a multi-pathway mechanism of action that involves cyclooxygenases (COXs) inhibition and nitric oxide (NO) donation. The first drug of this group is naproxcinod, which exerts rarely adverse effects of stomach, gut and less cardiovascular toxicity with naproxen. NO is an important mediator of endothelial function acting as a vasodilator and plays role in inflammation and pain perception that may be of relevance in osteoarthritis and in healing injures in stomach and gut. Lipoxins (LX, LXs): LXA4, LXB4 are group of lipid mediators leading to resolution of inflammation and protective influence on gastrointestinal mucosa. ATL (AT mean aspirin triggered therefore "depend on aspirin") synthesis, via COX-2, reduces the severity of damage gastrointestinal tract induced by NSAIDs. ATL also plays role in gastric adaptation during chronic aspirin administration. Antiinflammatory drugs hydrogen sulfide-releasing (H2S) (ATB-337 that consist of diclofenac linked to a hydrogen sulfide-releasing moiety) may show better efficacy and less toxicity. COX/5-LOX inhibitors and NO-NSAIDs heals symptoms of osteoarthrosis. PMID:21542252

  13. Blockade of TRPM7 Channel Activity and Cell Death by Inhibitors of 5-Lipoxygenase

    PubMed Central

    Chen, Hsiang-Chin; Xie, Jia; Zhang, Zheng; Su, Li-Ting; Yue, Lixia; Runnels, Loren W.

    2010-01-01

    TRPM7 is a ubiquitous divalent-selective ion channel with its own kinase domain. Recent studies have shown that suppression of TRPM7 protein expression by RNA interference increases resistance to ischemia-induced neuronal cell death in vivo and in vitro, making the channel a potentially attractive pharmacological target for molecular intervention. Here, we report the identification of the 5-lipoxygenase inhibitors, NDGA, AA861, and MK886, as potent blockers of the TRPM7 channel. Using a cell-based assay, application of these compounds prevented cell rounding caused by overexpression of TRPM7 in HEK-293 cells, whereas inhibitors of 12-lipoxygenase and 15-lipoxygenase did not prevent the change in cell morphology. Application of the 5-lipoxygenase inhibitors blocked heterologously expressed TRPM7 whole-cell currents without affecting the protein's expression level or its cell surface concentration. All three inhibitors were also effective in blocking the native TRPM7 current in HEK-293 cells. However, two other 5-lipoxygenase specific inhibitors, 5,6-dehydro-arachidonic acid and zileuton, were ineffective in suppressing TRPM7 channel activity. Targeted knockdown of 5-lipoxygenase did not reduce TRPM7 whole-cell currents. In addition, application of 5-hydroperoxyeicosatetraenoic acid (5-HPETE), the product of 5-lipoxygenase, or 5-HPETE's downstream metabolites, leukotriene B4 and leukotriene D4, did not stimulate TRPM7 channel activity. These data suggested that NDGA, AA861, and MK886 reduced the TRPM7 channel activity independent of their effect on 5-lipoxygenase activity. Application of AA861 and NDGA reduced cell death for cells overexpressing TRPM7 cultured in low extracellular divalent cations. Moreover, treatment of HEK-293 cells with AA861 increased cell resistance to apoptotic stimuli to a level similar to that obtained for cells in which TRPM7 was knocked down by RNA interference. In conclusion, NDGA, AA861, and MK886 are potent blockers of the TRPM7 channel

  14. [Proteasome inhibitor].

    PubMed

    Yagi, Hideo

    2014-06-01

    The ubiquitin-proteasome system plays an essential role in degradation of eukaryotic intracellular protein, including cell cycle regulation, cell growth and proliferation, and survival. Cancer cells generally have higher level of proteasome activity compared with normal cells, suggesting proteasome inhibition could be therapeutic target in oncology. Bortezomib, the first proteasome inhibitor introduced into the clinic, is approved for the treatment of patients with multiple myeloma (MM). Although it was approved as single agent in the relapsed setting, bortezomib is now predominantly used in combination with conventional and novel targeted agents because bortezomib has demonstrated additive and synergistic activity in preclinical studies. Recently, several second-generation proteasome inhibitors, such as carfilzomib and MLN9708, have been developed and entered into clinical trials. These agents were investigated in frontline MM in combination with lenalidomide and low-dose dexamethasone. These studies demonstrated positive efficacy and safety, and it is expected that they will be approved in near future. PMID:25016815

  15. Flavocoxid, a dual inhibitor of cyclooxygenase and 5-lipoxygenase, blunts pro-inflammatory phenotype activation in endotoxin-stimulated macrophages

    PubMed Central

    Altavilla, D; Squadrito, F; Bitto, A; Polito, F; Burnett, BP; Di Stefano, V; Minutoli, L

    2009-01-01

    Background and purpose: The flavonoids, baicalin and catechin, from Scutellaria baicalensis and Acacia catechu, respectively, have been used for various clinical applications. Flavocoxid is a mixed extract containing baicalin and catechin, and acts as a dual inhibitor of cyclooxygenase (COX) and 5-lipoxygenase (LOX) enzymes. The anti-inflammatory activity, measured by protein and gene expression of inflammatory markers, of flavocoxid in rat peritoneal macrophages stimulated with Salmonella enteritidis lipopolysaccharide (LPS) was investigated. Experimental approach: LPS-stimulated (1 µg·mL−1) peritoneal rat macrophages were co-incubated with different concentrations of flavocoxid (32–128 µg·mL−1) or RPMI medium for different incubation times. Inducible COX-2, 5-LOX, inducible nitric oxide synthase (iNOS) and inhibitory protein κB-α (IκB-α) levels were evaluated by Western blot analysis. Nuclear factor κB (NF-κB) binding activity was investigated by electrophoretic mobility shift assay. Tumour necrosis factor-α (TNF-α) gene and protein expression were measured by real-time polymerase chain reaction and enzyme-linked immunosorbent assay respectively. Finally, malondialdehyde (MDA) and nitrite levels in macrophage supernatants were evaluated. Key results: LPS stimulation induced a pro-inflammatory phenotype in rat peritoneal macrophages. Flavocoxid (128 µg·mL−1) significantly inhibited COX-2 (LPS = 18 ± 2.1; flavocoxid = 3.8 ± 0.9 integrated intensity), 5-LOX (LPS = 20 ± 3.8; flavocoxid = 3.1 ± 0.8 integrated intensity) and iNOS expression (LPS = 15 ± 1.1; flavocoxid = 4.1 ± 0.4 integrated intensity), but did not modify COX-1 expression. PGE2 and LTB4 levels in culture supernatants were consequently decreased. Flavocoxid also prevented the loss of IκB-α protein (LPS = 1.9 ± 0.2; flavocoxid = 7.2 ± 1.6 integrated intensity), blunted increased NF-κB binding activity (LPS = 9.2 ± 2; flavocoxid = 2.4 ± 0.7 integrated intensity) and the

  16. Autophagy inhibitors.

    PubMed

    Pasquier, Benoit

    2016-03-01

    Autophagy is a lysosome-dependent mechanism of intracellular degradation. The cellular and molecular mechanisms underlying this process are highly complex and involve multiple proteins, including the kinases ULK1 and Vps34. The main function of autophagy is the maintenance of cell survival when modifications occur in the cellular environment. During the past decade, extensive studies have greatly improved our knowledge and autophagy has exploded as a research field. This process is now widely implicated in pathophysiological processes such as cancer, metabolic, and neurodegenerative disorders, making it an attractive target for drug discovery. In this review, we will summarize the different types of inhibitors that affect the autophagy machinery and provide some potential therapeutic perspectives. PMID:26658914

  17. Inhibition of 5-lipoxygenase triggers apoptosis in prostate cancer cells via down-regulation of protein kinase C-epsilon

    PubMed Central

    Sarveswaran, Sivalokanathan; Thamilselvan, Vijayalakshmi; Brodie, Chaya; Ghosh, Jagadananda

    2012-01-01

    Previous studies have shown that human prostate cancer cells constitutively generate 5-lipoxygenase (5-LOX) metabolites from arachidonic acid, and inhibition of 5-LOX blocks production of 5-LOX metabolites and triggers apoptosis in prostate cancer cells. This apoptosis is prevented by exogenous metabolites of 5-LOX, suggesting an essential role of 5-LOX metabolites in the survival of prostate cancer cells. However, downstream signaling mechanisms which mediate the survival-promoting effects of 5-LOX metabolites in prostate cancer cells are still unknown. Recently, we reported that MK591, a specific inhibitor of 5-LOX activity, induces apoptosis in prostate cancer cells without inhibition of Akt, or ERK, two well-characterized regulators of pro-survival mechanisms, suggesting the existence of an Akt and ERK-independent survival mechanism in prostate cancer cells regulated by 5-LOX. Here, we report that 5-LOX inhibition-induced apoptosis in prostate cancer cells occurs via rapid inactivation of protein kinase C-epsilon (PKCε), and that exogenous 5-LOX metabolites prevent both 5-LOX inhibition-induced down-regulation of PKCε and induction of apoptosis. Interestingly, pre-treatment of prostate cancer cells with diazoxide (a chemical activator of PKCε), or KAE1-1 (a cell-permeable, octa-peptide specific activator of PKCε) prevents 5-LOX inhibition-induced apoptosis, which indicates that inhibition of 5-LOX triggers apoptosis in prostate cancer cells via down-regulation of PKCε. Altogether, these findings suggest that metabolism of arachidonic acid by 5-LOX activity promotes survival of prostate cancer cells via signaling through PKCε, a pro-survival serine/threonine kinase. PMID:21824498

  18. Proton pump inhibitors

    MedlinePlus

    Proton pump inhibitors (PPIs) are medicines that work by reducing the amount of stomach acid made by glands in ... Proton pump inhibitors are used to: Relieve symptoms of acid reflux, or gastroesophageal reflux disease (GERD). This is a ...

  19. Inhibition of soluble epoxide hydrolase enhances the anti-inflammatory effects of aspirin and 5-lipoxygenase activation protein inhibitor in a murine model.

    PubMed

    Liu, Jun-Yan; Yang, Jun; Inceoglu, Bora; Qiu, Hong; Ulu, Arzu; Hwang, Sung-Hee; Chiamvimonvat, Nipavan; Hammock, Bruce D

    2010-03-15

    Inflammation is a multi-staged process whose expansive phase is thought to be driven by acutely released arachidonic acid (AA) and its metabolites. Inhibition of cyclooxygenase (COX), lipoxygenase (LOX), or soluble epoxide hydrolase (sEH) is known to be anti-inflammatory. Inhibition of sEH stabilizes the cytochrome P450 (CYP450) products epoxyeicosatrienoic acids (EETs). Here we used a non-selective COX inhibitor aspirin, a 5-lipoxygenase activation protein (FLAP) inhibitor MK886, and a sEH inhibitor t-AUCB to selectively modulate the branches of AA metabolism in a lipopolysaccharide (LPS)-challenged murine model. We used metabolomic profiling to simultaneously monitor representative AA metabolites of each branch. In addition to the significant crosstalk among branches of the AA cascade during selective modulation of COX, LOX, or sEH, we demonstrated that co-administration of t-AUCB enhanced the anti-inflammatory effects of aspirin or MK886, which was evidenced by the observations that co-administration resulted in favorable eicosanoid profiles and better control of LPS-mediated hypotension as well as hepatic protein expression of COX-2 and 5-LOX. Targeted disruption of the sEH gene displayed a parallel profile to that produced by t-AUCB. These observations demonstrate a significant level of crosstalk among the three major branches of the AA cascade and that they are not simply parallel pathways. These data illustrate that inhibition of sEH by both pharmacological intervention and gene knockout enhances the anti-inflammatory effects of aspirin and MK886, suggesting the possibility of modulating multiple branches to achieve better therapeutic effects. PMID:19896470

  20. Elucidation of the molecular mechanism and the efficacy in vivo of a novel 1,4-benzoquinone that inhibits 5-lipoxygenase

    PubMed Central

    Schaible, A M; Filosa, R; Temml, V; Krauth, V; Matteis, M; Peduto, A; Bruno, F; Luderer, S; Roviezzo, F; Di Mola, A; Rosa, M; D'Agostino, B; Weinigel, C; Barz, D; Koeberle, A; Pergola, C; Schuster, D; Werz, O

    2014-01-01

    Background and Purpose 1,4-Benzoquinones are well-known inhibitors of 5-lipoxygenase (5-LOX, the key enzyme in leukotriene biosynthesis), but the molecular mechanisms of 5-LOX inhibition are not completely understood. Here we investigated the molecular mode of action and the pharmacological profile of the novel 1,4-benzoquinone derivative 3-((decahydronaphthalen-6-yl)methyl)-2,5-dihydroxycyclohexa-2,5-diene-1,4-dione (RF-Id) in vitro and its effectiveness in vivo. Experimental Approach Mechanistic investigations in cell-free assays using 5-LOX and other enzymes associated with eicosanoid biosynthesis were conducted, along with cell-based studies in human leukocytes and whole blood. Molecular docking of RF-Id into the 5-LOX structure was performed to illustrate molecular interference with 5-LOX. The effectiveness of RF-Id in vivo was also evaluated in two murine models of inflammation. Key Results RF-Id consistently suppressed 5-LOX product synthesis in human leukocytes and human whole blood. RF-Id also blocked COX-2 activity but did not significantly inhibit COX-1, microsomal PGE2 synthase-1, cytosolic PLA2 or 12- and 15-LOX. Although RF-Id lacked radical scavenging activity, reducing conditions facilitated its inhibitory effect on 5-LOX whereas cell stress impaired its efficacy. The reduced hydroquinone form of RF-Id (RED-RF-Id) was a more potent inhibitor of 5-LOX as it had more bidirectional hydrogen bonds within the 5-LOX substrate binding site. Finally, RF-Id had marked anti-inflammatory effects in mice in vivo. Conclusions and Implications RF-Id represents a novel anti-inflammatory 1,4-benzoquinone that potently suppresses LT biosynthesis by direct inhibition of 5-LOX with effectiveness in vivo. Mechanistically, RF-Id inhibits 5-LOX in a non-redox manner by forming discrete molecular interactions within the active site of 5-LOX. PMID:24467325

  1. Cannabidiol-2',6'-dimethyl ether, a cannabidiol derivative, is a highly potent and selective 15-lipoxygenase inhibitor.

    PubMed

    Takeda, Shuso; Usami, Noriyuki; Yamamoto, Ikuo; Watanabe, Kazuhito

    2009-08-01

    The inhibitory effect of nordihydroguaiaretic acid (NDGA) (a nonselective lipoxygenase (LOX) inhibitor)-mediated 15-LOX inhibition has been reported to be affected by modification of its catechol ring, such as methylation of the hydroxyl group. Cannabidiol (CBD), one of the major components of marijuana, is known to inhibit LOX activity. Based on the phenomenon observed in NDGA, we investigated whether or not methylation of CBD affects its inhibitory potential against 15-LOX, because CBD contains a resorcinol ring, which is an isomer of catechol. Although CBD inhibited 15-LOX activity with an IC(50) value (50% inhibition concentration) of 2.56 microM, its monomethylated and dimethylated derivatives, CBD-2'-monomethyl ether and CBD-2',6'-dimethyl ether (CBDD), inhibited 15-LOX activity more strongly than CBD. The number of methyl groups in the resorcinol moiety of CBD (as a prototype) appears to be a key determinant for potency and selectivity in inhibition of 15-LOX. The IC(50) value of 15-LOX inhibition by CBDD is 0.28 microM, and the inhibition selectivity for 15-LOX (i.e., the 5-LOX/15-LOX ratio of IC(50) values) is more than 700. Among LOX isoforms, 15-LOX is known to be able to oxygenate cholesterol esters in the low-density lipoprotein (LDL) particle (i.e., the formation of oxidized LDL). Thus, 15-LOX is suggested to be involved in development of atherosclerosis, and CBDD may be a useful prototype for producing medicines for atherosclerosis. PMID:19406952

  2. [Inhibitors of xanthine oxidoreductase].

    PubMed

    Okamoto, Ken

    2008-04-01

    Inhibitors of xanthine oxidoreductase decrease production of uric acid, thus they act as hypouricemic drugs. Allopurinol, a prototypical xanthine oxidoreductase inhibitor, has been widely prescribed for treatment of gout and hyperuricemia. However, severe side effects of allopurinol may occur in patients with renal insufficiency. Recently, novel nonpurine selective inhibitors of xanthine oxidoreductase have been developed as potential alternatives to allopurinol. They have different inhibition mechanisms, utilizing the enzyme structure and the reaction mechanism. Such variation of the inhibition mechanism affects/in vivo/hypouricemic effects of the inhibitors. PMID:18409526

  3. Novel corrosion inhibitor technology

    SciTech Connect

    Van de Ven, P.; Fritz, P.; Pellet, R.

    1999-11-01

    A novel, patented corrosion inhibitor technology has been identified for use in heat transfer applications such as automotive and heavy-duty coolant. The new technology is based on a low-toxic, virtually depletion-free carboxylic acid corrosion inhibitor package that performs equally well in mono ethylene glycol and in less toxic propylene glycol coolants. An aqueous inhibitor concentrate is available to provide corrosion protection where freezing protection is not an issue. In the present paper, this inhibitor package is evaluated in the different base fluids: mono ethylene glycol, mono propylene glycol and water. Results are obtained in both standardized and specific corrosion tests as well as in selected field trials. These results indicate that the inhibitor package remains effective and retains the benefits previously identified in automotive engine coolant applications: excellent corrosion protection under localized conditions, general corrosion conditions as well as at high temperature.

  4. Screening of telomerase inhibitors.

    PubMed

    Kleideiter, Elke; Piotrowska, Kamilla; Klotz, Ulrich

    2007-01-01

    Shortening of telomeres prevents cells from uncontrolled proliferation. Progressive telomere shortening occurs at each cell division until a critical telomeric length is reached. Telomerase expression is switched off after embryonic differentiation in most normal cells, but it is expressed in a very high percentage of tumors of different origin. Thus, telomerase is regarded as the best tumor marker and a promising novel molecular target for cancer treatment. Therefore, different strategies to inhibit telomerase have been developed. However, systematic screening of telomerase inhibitors has not been performed to compare their therapeutic potential. We propose a suitable strategy for estimation of the therapeutic potential of telomerase inhibitors, which is based on a systematic screening of different inhibitors in the same cell system. From the long list of compounds discussed in the literature, we have selected four telomerase inhibitors of different structure and mode of action: BRACO19 (G-quadruplex-interactive compound), BIBR1532 (non-nucleosidic reverse transcriptase inhibitor), 2'-O-methyl RNA, and peptide nucleic acids (PNAs; hTR antisense oligonucleotides). To determine minimal effective concentrations for telomerase inhibition, telomerase activity was measured using the cell-free telomerase repeat amplification protocol (TRAP) assay. We also tested inhibitors in long-term cell-culture experiments by exposing A-549 cells to non-cytotoxic concentrations of inhibitors for a period of 99 days. Subsequently, telomerase activity of A-549 cells was investigated using the TRAP assay, and telomere length of samples was assessed by telomere restriction fragment (TRF) Southern blot analysis. PMID:18369824

  5. Synthetic inhibitors of elastase.

    PubMed

    Edwards, P D; Bernstein, P R

    1994-03-01

    For more than two decades investigators around the world, in both academic and industrial institutions, have been developing inhibitors of human neutrophil elastase. A number of very elegant and insightful strategies have been reported. In the case of reversible peptidic inhibitors, this has resulted in the identification of some extremely potent compounds with dissociation constants in the 10(-11) M range. This is quite an accomplishment considering that these low molecular-weight inhibitors are only tri- and tetrapeptides. In the case of the heterocyclic-based inhibitors, the challenge of balancing the heterocycle's inherent reactivity and aqueous stability with the stability of the enzyme-inhibitor adduct has been meet by either using a latent, reactive functionality which is only activated within the enzyme, or by incorporating features which selectively obstruct deacylation but have little effect on the enzyme acylation step. The underlying goal of this research has been the identification of agents to treat diseases associated with HNE. Several animal models have been developed for evaluating the in vivo activity of elastase inhibitors, and compounds have been shown to be effective in all of these models by the intravenous, intratrachael or oral routes of administration. However, only a very small percentage of compounds have possessed all the necessary properties, including lack of toxicity, for progression into the clinic. The peptidyl TFMK ICI 200,880 (25-12) has many of the desired characteristics of a drug to treat the diseases associated with HNE: chemical stability, in vitro and in vivo activity, a long duration of action, and adequate metabolic stability. Currently ICI 200,880 is the only low molecular-weight HNE inhibitor known to be undergoing clinical trials, and may be the compound which finally demonstrates the clinical utility of a synthetic HNE inhibitor. PMID:8189835

  6. [STAT3 inhibitor].

    PubMed

    Kitamura, Toshio

    2011-01-01

    Clinical efficacies of various molecular-targeted drugs have been recently demonstrated. Most of these drugs are kinase inhibitors. A most successful drug Glivec is an inhibitor of Bcr-Abl fusion kinase, derived from a well-known causative chromosome translocation of chronic myeloid leukemia(CML). Although other kinase inhibitors have also proved to be useful in the therapy of malignant diseases including an ALK inhibitor for lung carcinomas, a general problem of kinase inhibitors is their lowspecificities. Therefore, the complication of these drugs must be overcome. Recently, trials to develop moleculartargeted therapy whose targets are molecules other than kinases have also been promising. Among molecular targets, STAT3 has attracted a great deal of researchers' attention because it is constitutively activated in most malignant tumors and plays important roles in carcinogenesis. This article summarizes the current situation and problems to be solved with STAT3 inhibitors as well as our recent findings on the molecular mechanisms of STAT3 activation. PMID:21368456

  7. Aromatase and its inhibitors.

    PubMed

    Brodie, A; Lu, Q; Long, B

    1999-01-01

    Inhibitors of aromatase (estrogen synthetase) have been developed as treatment for postmenopausal breast cancer. Both steroidal substrate analogs, type I inhibitors, which inactivate the enzyme and non-steroidal competitive reversible, type II inhibitors, are now available. 4-hydroxyandrostenedione (4-OHA), the first selective aromatase inhibitor, has been shown to reduce serum estrogen concentrations and cause complete and partial responses in approximately 25% of patients with hormone responsive disease who have relapsed from previous endocrine treatment. Letrozole (CGS 20, 269) and anastrozole (ZN 1033) have been recently approved for treatment. Both suppress serum estrogen levels to the limit of assay detection. Letrozole has been shown to be significantly superior to megace in overall response rates and time to treatment failure, whereas anastrozole was found to improve survival in comparison to megace. Both were better tolerated than the latter. The potential of aromatase within the breast as a significant source of estrogen mediating tumor proliferation and which might determine the outcome of inhibitor treatment was explored. Using immunocytochemistry and in situ hybridization, aromatase and mRNAarom was detected mainly in the epithelial cells of the terminal ductal lobular units (TDLU) of the normal breast and also in breast tumor epithelial cells as well as some stromal cells. Increase in proliferation, measured by increased thymidine incorporation into DNA and by PCNA immunostaining in response to testosterone was observed in histocultures of breast cancer samples. This effect could be inhibited by 4-OHA and implies that intratumoral aromatase has functional significance. An intratumoral aromatase model in the ovariectomized nude mouse was developed which simulated the hormone responsive postmenopausal breast cancer patient. This model also allows evaluation of the efficacy of aromatase inhibitors and antiestrogens in tumors of estrogen receptor positive

  8. Small-molecule caspase inhibitors

    NASA Astrophysics Data System (ADS)

    Zhenodarova, S. M.

    2010-02-01

    The review considers low-molecular weight inhibitors of caspases, cysteine proteases being key contributors to apoptosis (programmed cell death). The inhibitors with aspartic acid residues or various heterocyclic systems (both synthetic and natural) are covered. Their possible mechanisms of action are discussed. Data on inhibitor structure-activity relationship studies are systematically surveyed. The interactions of the non-peptide fragments of an inhibitor with the enzymes are examined. Examples of the use of some inhibitors for apoptosis suppression are provided.

  9. SGLT2 inhibitors.

    PubMed

    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. PMID:26362302

  10. Cholinesterase inhibitors from botanicals.

    PubMed

    Ahmed, Faiyaz; Ghalib, Raza Murad; Sasikala, P; Ahmed, K K Mueen

    2013-07-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disease, wherein a progressive loss of cholinergic synapses occurs in hippocampus and neocortex. Decreased concentration of the neurotransmitter, acetylcholine (ACh), appears to be critical element in the development of dementia, and the most appropriate therapeutic approach to treat AD and other form of dementia is to restore acetylcholine levels by inhibiting both major form of cholinesterase: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Consequently, researches have focused their attention towards finding cholinesterase inhibitors from natural products. A large number of such inhibitors have been isolated from medicinal plants. This review presents a comprehensive account of the advances in field of cholinesterase inhibitor phytoconstituents. The structures of some important phytoconstituents (collected through www.Chemspider.com) are also presented and the scope for future research is discussed. PMID:24347920

  11. Cholinesterase inhibitors from botanicals

    PubMed Central

    Ahmed, Faiyaz; Ghalib, Raza Murad; Sasikala, P.; Ahmed, K. K. Mueen

    2013-01-01

    Alzheimer's disease (AD) is a progressive neurodegenerative disease, wherein a progressive loss of cholinergic synapses occurs in hippocampus and neocortex. Decreased concentration of the neurotransmitter, acetylcholine (ACh), appears to be critical element in the development of dementia, and the most appropriate therapeutic approach to treat AD and other form of dementia is to restore acetylcholine levels by inhibiting both major form of cholinesterase: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Consequently, researches have focused their attention towards finding cholinesterase inhibitors from natural products. A large number of such inhibitors have been isolated from medicinal plants. This review presents a comprehensive account of the advances in field of cholinesterase inhibitor phytoconstituents. The structures of some important phytoconstituents (collected through www.Chemspider.com) are also presented and the scope for future research is discussed. PMID:24347920

  12. Protein protease inhibitors in insects and comparison with mammalian inhibitors.

    PubMed

    Eguchi, M

    1993-01-01

    1. Studies on insect protein protease inhibitors are summarized. Biochemical, genetic and physiological investigations of the silkworm are performed. 2. In addition, the properties and characteristics of fungal protease inhibitors from the silkworm (Bombyx mori) are described and their importance as defensive functions is emphasized. 3. This review also concerns comparative and evolutionary studies of protease inhibitors from various sources. 4. The biological significance of inhibitors is discussed in view of the extensive experimental results. PMID:8365101

  13. Sunflower trypsin inhibitor-1.

    PubMed

    Korsinczky, Michael L J; Schirra, Horst Joachim; Craik, David J

    2004-10-01

    SFTI-1 is a bicyclic 14 amino acid peptide that was originally isolated from the seeds of the sunflower Helianthus annuus. It is a potent inhibitor of trypsin, with a sub-nanomolar K(i) value and is homologous to the active site region of the well-known family of serine protease inhibitors known as the Bowman-Birk trypsin inhibitors. It has a cyclic backbone that is cross-braced by a single disulfide bridge and a network of hydrogen bonds that result in a well-defined structure. SFTI-1 is amenable to chemical synthesis, allowing for the creation of synthetic variants. Alterations to the structure such as linearising the backbone or removing the disulfide bridge do not reduce the potency of SFTI-1 significantly, and minimising the peptide to as few as nine residues results in only a small decrease in reactivity. The creation of linear variants of SFTI-1 also provides a tool for investigating putative linear precursor peptides. The mechanism of biosynthesis of SFTI-1 is not yet known but it seems likely that it is a gene-coded product that has arisen from a precursor protein that may be evolutionarily related to classic Bowman-Birk inhibitors. PMID:15544530

  14. Inhibitors of rhomboid proteases.

    PubMed

    Wolf, Eliane V; Verhelst, Steven H L

    2016-03-01

    Rhomboid proteases form one of the most widespread families of intramembrane proteases. They utilize a catalytic serine-histidine dyad located several Å below the surface of the membrane for substrate hydrolysis. Multiple studies have implicated rhomboid proteases in biologically and medically relevant processes. Several assays have been developed that are able to monitor rhomboid activity. With the aid of these assays, different types of inhibitors have been found, all based on electrophiles that covalently react with the active site machinery. Although the currently available inhibitors have limited selectivity and moderate potency, they can function as research tools and as starting point for the development of activity-based probes, which are reagents that can specifically detect active rhomboid species. Structural studies on complexes of inhibitors with the Escherichia coli rhomboid GlpG have provided insight into how substrate recognition may occur. Future synthetic efforts, aided by high-throughput screening or structure-based design, may lead to more potent and selective inhibitors for this interesting family of proteases. PMID:26166068

  15. Recent advances for FLAP inhibitors.

    PubMed

    Pettersen, Daniel; Davidsson, Öjvind; Whatling, Carl

    2015-07-01

    A number of FLAP inhibitors have been progressed to clinical trials for respiratory and other inflammatory indications but so far no drug has reached the market. With this Digest we assess the opportunity to develop FLAP inhibitors for indications beyond respiratory disease, and in particular for atherosclerotic cardiovascular disease. We also show how recently disclosed FLAP inhibitors have structurally evolved from the first generation FLAP inhibitors paving the way for new compound classes. PMID:26004579

  16. Minocycline protects PC12 cells against NMDA-induced injury via inhibiting 5-lipoxygenase activation.

    PubMed

    Song, Ying; Wei, Er-Qing; Zhang, Wei-Ping; Ge, Qiu-Fu; Liu, Jian-Ren; Wang, Meng-Ling; Huang, Xiao-Jia; Hu, Xin; Chen, Zhong

    2006-04-26

    Recently, we have reported that minocycline, a semi-synthetic tetracycline with neuroprotective effects, inhibits the in vitro ischemic-like injury and 5-lipoxygenase (5-LOX) activation in PC12 cells. In the present study, we further determined whether minocycline protects PC12 cells from excitotoxicity via inhibiting 5-LOX activation. We used N-methyl-d-aspartate (NMDA, 200 microM) to induce early (exposure for 6 h) and delayed (exposure for 6 h followed by 24 h recovery) injuries. We found that NMDA receptor antagonist ketamine, 5-LOX inhibitor caffeic acid and minocycline concentration dependently attenuated NMDA-induced early and delayed cell injuries (viability reduction and cell death). However, only ketamine (1 microM) inhibited NMDA-evoked elevation of intracellular calcium. In addition, immunohistochemical analysis showed that NMDA induced 5-LOX translocation to the nuclear membrane after 1- to 6-h exposure which was confirmed by Western blotting, indicating that 5-LOX was activated. Ketamine, caffeic acid and minocycline (each at 1 microM) inhibited 5-LOX translocation after early injury. After delayed injury, PC12 cells were shrunk, and 5-LOX was translocated to the nuclei and nuclear membrane; ketamine, caffeic acid and minocycline inhibited both cell shrinking and 5-LOX translocation. As a control, 12-LOX inhibitor baicalein showed a weak effect on cell viability and death, but no effect on 5-LOX translocation. Therefore, we conclude that the protective effect of minocycline on NMDA-induced injury is partly mediated by inhibiting 5-LOX activation. PMID:16574083

  17. Alpha glucosidase inhibitors.

    PubMed

    Kalra, Sanjay

    2014-04-01

    Alpha glucosidase inhibitors (AGIs) are a unique class of anti-diabetic drugs. Derived from bacteria, these oral drugs are enzyme inhibitors which do not have a pancreato -centred mechanism of action. Working to delay carbohydrate absorption in the gastrointestinal tract, they control postprandial hyperglycaemia and provide unquestioned cardiovascular benefit. Specially suited for a traditional Pakistani carbohydrate-rich diet, AGIs have been termed the 'untapped diamonds' of diabetology. The use of these oral antidiabetic drugs (OADs) that target pathophysiology in the early stages of type 2 diabetes, notably to reduce postprandial hyperglycaemia and hyperinsulinaemia will inevitably increase with time. This review describes the history of their development, mechanism of action, basic and clinical pharmacology, and suggests practical, evidence-based guidance for their optimal use. PMID:24864650

  18. [JAK2 inhibitors].

    PubMed

    Hernández Boluda, Juan Carlos; Gómez, Montse; Pérez, Ariadna

    2016-07-15

    Pharmacological inhibition of the kinase activity of JAK proteins can interfere with the signaling of immunomodulatory cytokines and block the constitutive activation of the JAK-STAT pathway that characterizes certain malignancies, including chronic myeloproliferative neoplasms. JAK inhibitors may, therefore, be useful to treat malignancies as well as inflammatory or immune disorders. Currently, the most significant advances have been made in the treatment of myelofibrosis, where these drugs may lead to a remarkable improvement in the control of hyperproliferative manifestations. However, available data suggest that this treatment is not curative of myelofibrosis. In general, JAK2 inhibition induces cytopaenias, with this being considered a class side-effect. By contrast, the extrahaematologic toxicity profile varies significantly among the different JAK inhibitors. At present, there are several clinical trials evaluating the combination of ruxolitinib with other drugs, in order to improve its therapeutic activity as well as reducing haematologic toxicity. PMID:27033437

  19. PARP inhibitors and more.

    PubMed

    Bose, Chinmoy K; Basu, Nirban

    2015-01-01

    Polyadenosine diphosphate (ADP) ribose polymerase (PARP) lends a panoramic view to the inner mystery of protection of integrity of deoxyribonucleic acid (DNA) in a cell genome. They are a balancing part of an even more dynamic equilibrium of normalcy against daily assaults. PARP finds its companion candidates in other tumor suppressors, with the most prominent and glaring one being breast cancer (BRCA) 1 and 2. The strength of both is split by PARP inhibitors, inculcating the synthetic lethality of tumor cell, which is now in the market for ovarian cancer treatment. There are many reasons for the resistance of such inhibitors, which are now becoming clinically important. These are seen along with other damage repair approaches. PMID:26097394

  20. PARP inhibitors and more

    PubMed Central

    Bose, Chinmoy K.; Basu, Nirban

    2015-01-01

    Polyadenosine diphosphate (ADP) ribose polymerase (PARP) lends a panoramic view to the inner mystery of protection of integrity of deoxyribonucleic acid (DNA) in a cell genome. They are a balancing part of an even more dynamic equilibrium of normalcy against daily assaults. PARP finds its companion candidates in other tumor suppressors, with the most prominent and glaring one being breast cancer (BRCA) 1 and 2. The strength of both is split by PARP inhibitors, inculcating the synthetic lethality of tumor cell, which is now in the market for ovarian cancer treatment. There are many reasons for the resistance of such inhibitors, which are now becoming clinically important. These are seen along with other damage repair approaches. PMID:26097394

  1. Benzoylurea Chitin Synthesis Inhibitors.

    PubMed

    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. PMID:26168369

  2. Mineralization by Inhibitor Exclusion

    PubMed Central

    Price, Paul A.; Toroian, Damon; Lim, Joo Eun

    2009-01-01

    One of our goals is to understand the mechanisms that deposit mineral within collagen fibrils, and as a first step we recently determined the size exclusion characteristics of the fibril. This study revealed that apatite crystals up to 12 unit cells in size can access the water within the fibril, whereas molecules larger than a 40-kDa protein are excluded. Based on these observations, we proposed a novel mechanism for fibril mineralization: that macromolecular inhibitors of apatite growth favor fibril mineralization by selectively inhibiting crystal growth in the solution outside of the fibril. To test this mechanism, we developed a system in which crystal formation is driven by homogeneous nucleation at high calcium phosphate concentration and the only macromolecule in solution is fetuin, a 48-kDa inhibitor of apatite growth. Our experiments with this system demonstrated that fetuin determines the location of mineral growth; in the presence of fetuin mineral grows exclusively within the fibril, whereas in its absence mineral grows in solution outside the fibril. Additional experiments showed that fetuin is also able to localize calcification to the interior of synthetic matrices that have size exclusion characteristics similar to those of collagen and that it does so by selectively inhibiting mineral growth outside of these matrices. We termed this new calcification mechanism “mineralization by inhibitor exclusion,” the selective mineralization of a matrix using a macromolecular inhibitor of mineral growth that is excluded from that matrix. Future studies will be needed to evaluate the possible role of this mechanism in bone mineralization. PMID:19414589

  3. Neutrophil Elastase Inhibitors

    PubMed Central

    Groutas, William C.; Dou, Dengfeng; Alliston, Kevin R.

    2011-01-01

    Introduction Chronic obstructive pulmonary disease (COPD) constitutes a worldwide health problem. There is currently an urgent and unmet need for the development of small molecule therapeutics capable of blocking and/or reversing the progression of the disorder. Recent studies have greatly illuminated our understanding of the multiple pathogenic processes associated with COPD. Of paramount importance is the key role played by proteases, oxidative stress, apoptosis, and inflammation. Insights gained from these studies have made possible the exploration of new therapeutic approaches. Areas covered An overview of major developments in COPD research with emphasis on low molecular weight neutrophil elastase inhibitors is described in this review. Expert opinion Great strides have been made toward our understanding of the biochemical and cellular events associated with COPD. However, our knowledge regarding the inter-relationships among the multiple pathogenic mechanisms and their mediators involved is till limited. The problem is further compounded by the unavailability of suitable validated biomarkers for assessing the efficacy of potential therapeutic interventions. The complexity of COPD suggests that effective therapeutic interventions may require the administration of more than one agent such as, for instance, an HNE or MMP-12 inhibitor with an anti-inflammatory agent such as a phosphodiesterase-4 inhibitor, or a dual function agent capable of disrupting the cycle of proteolysis, apoptosis, inflammation and oxidative stress PMID:21235378

  4. Development of scale inhibitors

    SciTech Connect

    Gill, J.S.

    1996-12-01

    During the last fifty years, scale inhibition has gone from an art to a science. Scale inhibition has changed from simple pH adjustment to the use of optimized dose of designer polymers from multiple monomers. The water-treatment industry faces many challenges due to the need to conserve water, availability of only low quality water, increasing environmental regulations of the water discharge, and concern for human safety when using acid. Natural materials such as starch, lignin, tannin, etc., have been replaced with hydrolytically stable organic phosphates and synthetic polymers. Most progress in scale inhibition has come from the use of synergistic mixtures and copolymerizing different functionalities to achieve specific goals. Development of scale inhibitors requires an understanding of the mechanism of crystal growth and its inhibition. This paper discusses the historic perspective of scale inhibition and the development of new inhibitors based on the understanding of the mechanism of crystal growth and the use of powerful tools like molecular modeling to visualize crystal-inhibitor interactions.

  5. Thymidylate synthase inhibitors.

    PubMed

    Danenberg, P V; Malli, H; Swenson, S

    1999-12-01

    Thymidylate synthase (TS) is a critical enzyme for DNA replication and cell growth because it is the only de novo source of thymine nucleotide precursors for DNA synthesis. TS is the primary target of 5-fluorouracil (5-FU), which has been used for cancer treatment for more than 40 years. However, dissatisfaction with the overall activity of 5-FU against the major cancers, and the recognition that TS still remains an attractive target for anticancer drugs because of its central position in the pathway of DNA synthesis, led to a search for new inhibitors of TS structurally analogous to 5,10-methylenetetrahydrofolate, the second substrate of TS. TS inhibitory antifolates developed to date that are in various stages of clinical evaluation are ZD 1694 and ZD9331 (Astra-Zeneca, London, UK), (Eli Lilly, Indianapolis, IN), LY231514 (BW1843U89 (Glaxo-Wellcome, Research Triangle Park, NC), and AG337 and AG331 (Agouron, La Jolla, CA). Although each of these compounds has TS as its major intracellular site of action, they differ in propensity for polyglutamylation and for transport by the reduced folate carrier. LY231514 also has secondary target enzymes. As a result, each compound is likely to have a different spectrum of antitumor activity and toxicity. This review will summarize the development and properties of this new class of TS inhibitors. PMID:10606255

  6. Synthesis of Lysine Methyltransferase Inhibitors

    NASA Astrophysics Data System (ADS)

    Ye, Tao; Hui, Chunngai

    2015-07-01

    Lysine methyltransferase which catalyze methylation of histone and nonhistone proteins, play a crucial role in diverse biological processes and has emerged as a promising target for the development of various human diseases, including cancer, inflammation, and psychiatric disorders. However, inhibiting Lysine methyltransferases selectively has presented many challenges to medicinal chemists. During the past decade, lysine methyltransferase inhibitors covering many different structural classes have been designed and developed. In this review, we describe the development of selective, small-molecule inhibitors of lysine methyltransferases with an emphasis on their discovery and chemical synthesis. We highlight the current state of lysine methyltransferase inhibitors and discuss future directions and opportunities for lysine methyltransferase inhibitor discovery.

  7. [Kinase inhibitors and their resistance].

    PubMed

    Togashi, Yosuke; Nishio, Kazuto

    2015-08-01

    Kinase cascades are involved in all stages of tumorigenesis through modulation of transformation and differentiation, cell-cycle progression, and motility. Advances in molecular targeted drug development allow the design and synthesis of inhibitors targeting cancer-associated signal transduction pathways. Potent selective inhibitors with low toxicity can benefit patients especially with several malignancies harboring an oncogenic driver addictive signal. This article evaluates information on solid tumor-related kinase signals and inhibitors, including receptor tyrosine kinase or serine/threonine kinase signals that lead to successful application in clinical settings. In addition, the resistant mechanisms to the inhibitors is summarized. PMID:26281685

  8. Repositioning of DHFR Inhibitors.

    PubMed

    Lele, Arundhati Chandrashekhar; Mishra, Deepak Amarnath; Kamil, Tengku Karmila; Bhakta, Sanjib; Degani, Mariam Sohel

    2016-01-01

    Development of new drugs is a time-consuming, hugely expensive and an uncertain endeavor. The pharmaceutical industry is looking for cost-effective alternatives with reduced risks of drug failure. Validated target machinery along with established inhibitors indicates usefulness in drug design, discovery and further development. Folate metabolism, found in both prokaryotes and eukaryotes, represents an essential druggable target for chemotherapy. Numerous enzymes in the cell replication cycle use folate either as a cofactor or as a substrate. DHFR, an enzyme of the folate biosynthesis pathway is an established chemotherapeutic target, initially explored for anti-cancer drug discovery. Diaminopteridines e.g. methotrexate and aminopterin, primarily used as anti-cancer agents, are folic acid analogues, first reported in late 1940's, used to produce temporary remission of acute leukaemia in children. However, due to the toxicity of these drugs, they could not be used for other therapeutic implications such as in the treatment of infectious diseases. Development of newer diaminopteridine derivatives has helped in repositioning their therapeutic usefulness. These analogues have now been proven as anti-parasitic, immuno-suppressants, anti-bacterial agents, to enlist a few therapeutic applications. Likewise, diaminopyrimidine, diaminoquinazoline and diaminodihydrotriazines are being explored for structural modifications by which they can be repurposed from their originally developed medicinal applicability and exploited for various other infectious disease conditions. In this review, we encompass the study of DHFR inhibitors potentially to be repurposed for different infectious disease case scenario and also highlight the novel anti-infective drug discovery benefits therein. PMID:26881719

  9. Osteocompatibility of Biofilm Inhibitors

    PubMed Central

    Rawson, Monica; Haggard, Warren; Jennings, Jessica A

    2014-01-01

    The demand for infection prevention therapies has led to the discovery of several biofilm inhibitors. These inhibiting signals are released by bacteria, fungi, or marine organisms to signal biofilm dispersal or disruption in Gram-positive, Gram-negative, and fungal microorganisms. The purpose of this study was to test the biocompatibility of five different naturally-produced biofilm chemical dispersal and inhibition signals with osteoblast-like cells: D-amino acids (D-AA), lysostaphin (LS), farnesol, cis-2-decenoic acid (C2DA), and desformyl flustrabromine (dFBr). In this preliminary study, compatibility of these anti-biofilm agents with differentiating osteoblasts was examined over a 21 days period at levels above and below concentrations active against bacterial biofilm. Anti-biofilm compounds listed above were serially diluted in osteogenic media and added to cultures of MC3T3 cells. Cell viability and cytotoxicity, after exposure to each anti-biofilm agent, were measured using a DNA assay. Differentiation characteristics of osteoblasts were determined qualitatively by observing staining of mineral deposits and quantitatively with an alkaline phosphatase assay. D-AA, LS, and C2DA were all biocompatible within the reported biofilm inhibitory concentration ranges and supported osteoblast differentiation. Farnesol and dFBr induced cytotoxic responses within the reported biofilm inhibitory concentration range and low doses of dFBr were found to inhibit osteoblast differentiation. At high concentrations, such as those that may be present after local delivery, many of these biofilm inhibitors can have effects on cellular viability and osteoblast function. Concentrations at which negative effects on osteoblasts occur should serve as upper limits for delivery to orthopaedic trauma sites and guide development of these potential therapeutics for orthopaedics. PMID:25505496

  10. Biological abatement of cellulase inhibitors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  11. Proteinaceous alpha-amylase inhibitors.

    PubMed

    Svensson, Birte; Fukuda, Kenji; Nielsen, Peter K; Bønsager, Birgit C

    2004-02-12

    Proteins that inhibit alpha-amylases have been isolated from plants and microorganisms. These inhibitors can have natural roles in the control of endogenous alpha-amylase activity or in defence against pathogens and pests; certain inhibitors are reported to be antinutritional factors. The alpha-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-amylases in complex with inhibitors from five families. These structures indicate major diversity but also some similarity in the structural basis of alpha-amylase inhibition. Mutational analysis of the mechanism of inhibition was performed in a few cases and various protein engineering and biotechnological approaches have been outlined for exploitation of the inhibitory function. PMID:14871655

  12. Oxidized mucus proteinase inhibitor: a fairly potent neutrophil elastase inhibitor.

    PubMed Central

    Boudier, C; Bieth, J G

    1994-01-01

    N-chlorosuccinimide oxidizes one of the methionine residues of mucus proteinase inhibitor with a second-order rate constant of 1.5 M-1.s-1. Cyanogen bromide cleavage and NH2-terminal sequencing show that the modified residue is methionine-73, the P'1 component of the inhibitor's active centre. Oxidation of the inhibitor decreases its neutrophil elastase inhibitory capacity but does not fully abolish it. The kinetic parameters describing the elastase-oxidized inhibitor interaction are: association rate constant kass. = 2.6 x 10(5) M-1.s-1, dissociation rate constant kdiss. = 2.9 x 10(-3) s-1 and equilibrium dissociation constant Ki = 1.1 x 10(-8) M. Comparison with the native inhibitor indicates that oxidation decreases kass. by a factor of 18.8 and increases kdiss. by a factor of 6.4, and therefore leads to a 120-fold increase in Ki. Yet, the oxidized inhibitor may still act as a potent elastase inhibitor in the upper respiratory tract where its concentration is 500-fold higher than Ki, i.e. where the elastase inhibition is pseudo-irreversible. Experiments in vitro with fibrous human lung elastin, the most important natural substrate of elastase, support this view: 1.35 microM elastase is fully inhibited by 5-6 microM oxidized inhibitor whether the enzyme-inhibitor complex is formed in the presence or absence of elastin and whether elastase is pre-adsorbed on elastin or not. PMID:7945266

  13. Flavivirus Entry Inhibitors.

    PubMed

    Wang, Qing-Yin; Shi, Pei-Yong

    2015-09-11

    Many flaviviruses are significant human pathogens that are transmitted by mosquitoes and ticks. Although effective vaccines are available for yellow fever virus, Japanese encephalitic virus, and tick-borne encephalitis virus, these and other flaviviruses still cause thousands of human deaths and millions of illnesses each year. No clinically approved antiviral therapy is available for flavivirus treatment. To meet this unmet medical need, industry and academia have taken multiple approaches to develop antiflavivirus therapy, among which targeting viral entry has been actively pursued in the past decade. Here we review the current knowledge of flavivirus entry and its use for small molecule drug discovery. Inhibitors of two major steps of flaviviral entry have been reported: (i) molecules that block virus-receptor interaction; (ii) compounds that prevent conformational change of viral envelope protein during virus-host membrane fusion. We also discuss the advantages and disadvantages of targeting viral entry for treatment of flavivirus infection as compared to targeting viral replication proteins. PMID:27617926

  14. Synthetic conversion of ACAT inhibitor to acetylcholinesterase inhibitor.

    PubMed

    Obata, R; Sunazuka, T; Otoguro, K; Tomoda, H; Harigaya, Y; Omura, S

    2000-06-19

    Natural product acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor pyripyropene A was synthetically converted to acetylcholinesterase (AChE) inhibitor via heterolitic cleavage of the 2-pyrone ring, followed by gamma-acylation/cyclization with several aroyl chlorides. The 4-pyridyl analogue selectively showed AChE inhibitory activity (IC50 7.9 microM) and no ACAT inhibitory activity IC50 = >1000 microM. PMID:10890154

  15. Synthesis of lysine methyltransferase inhibitors

    PubMed Central

    Hui, Chunngai; Ye, Tao

    2015-01-01

    Lysine methyltransferase which catalyze methylation of histone and non-histone proteins, play a crucial role in diverse biological processes and has emerged as a promising target for the development of various human diseases, including cancer, inflammation, and psychiatric disorders. However, inhibiting lysine methyltransferases selectively has presented many challenges to medicinal chemists. During the past decade, lysine methyltransferase inhibitors covering many different structural classes have been designed and developed. In this review, we describe the development of selective, small-molecule inhibitors of lysine methyltransferases with an emphasis on their discovery and chemical synthesis. We highlight the current state of lysine methyltransferase inhibitors and discuss future directions and opportunities for lysine methyltransferase inhibitor discovery. PMID:26258118

  16. Targeting cancer with kinase inhibitors

    PubMed Central

    Gross, Stefan; Rahal, Rami; Stransky, Nicolas; Lengauer, Christoph; Hoeflich, Klaus P.

    2015-01-01

    Kinase inhibitors have played an increasingly prominent role in the treatment of cancer and other diseases. Currently, more than 25 oncology drugs that target kinases have been approved, and numerous additional therapeutics are in various stages of clinical evaluation. In this Review, we provide an in-depth analysis of activation mechanisms for kinases in cancer, highlight recent successes in drug discovery, and demonstrate the clinical impact of selective kinase inhibitors. We also describe the substantial progress that has been made in designing next-generation inhibitors to circumvent on-target resistance mechanisms, as well as ongoing strategies for combining kinase inhibitors in the clinic. Last, there are numerous prospects for the discovery of novel kinase targets, and we explore cancer immunotherapy as a new and promising research area for studying kinase biology. PMID:25932675

  17. Aromatase inhibitors for male infertility.

    PubMed

    Schlegel, Peter N

    2012-12-01

    Some men with severely defective sperm production commonly have excess aromatase activity, reflected by low serum testosterone and relatively elevated estradiol levels. Aromatase inhibitors can increase endogenous testosterone production and serum testosterone levels. Treatment of infertile males with the aromatase inhibitors testolactone, anastrazole, and letrozole has been associated with increased sperm production and return of sperm to the ejaculate in men with non-obstructive azoospermia. Use of the aromatase inhibitors anastrazole (1 mg/day) and letrozole (2.5 mg/day) represent off-label use of these agents for impaired spermatogenesis in men with excess aromatase activity (abnormal testosterone/estradiol [T/E] ratios). Side effects have rarely been reported. Randomized controlled trials are needed to define the magnitude of benefit of aromatase inhibitor treatment for infertile men. PMID:23103016

  18. Selective Inhibitors of Protein Methyltransferases

    PubMed Central

    2015-01-01

    Mounting evidence suggests that protein methyltransferases (PMTs), which catalyze methylation of histone and nonhistone proteins, play a crucial role in diverse biological processes and human diseases. In particular, PMTs have been recognized as major players in regulating gene expression and chromatin state. PMTs are divided into two categories: protein lysine methyltransferases (PKMTs) and protein arginine methyltransferases (PRMTs). There has been a steadily growing interest in these enzymes as potential therapeutic targets and therefore discovery of PMT inhibitors has also been pursued increasingly over the past decade. Here, we present a perspective on selective, small-molecule inhibitors of PMTs with an emphasis on their discovery, characterization, and applicability as chemical tools for deciphering the target PMTs’ physiological functions and involvement in human diseases. We highlight the current state of PMT inhibitors and discuss future directions and opportunities for PMT inhibitor discovery. PMID:25406853

  19. [Cancer therapy by PARP inhibitors].

    PubMed

    Seimiya, Hiroyuki

    2015-08-01

    Poly(ADP-ribose) polymerases(PARP) synthesize the ADP-ribose polymers onto proteins and play a role in DNA repair. PARP inhibitors block the repair of single-strand breaks, which in turn gives rise to double-strand breaks during DNA replication. Thus, PARP inhibitors elicit synthetic lethality in cancer with BRCA1/2 loss-of-function mutations that hamper homologous recombination repair of double-strand breaks. Olaparib, the first-in-class PARP inhibitor, was approved for treatment of BRCA-mutated ovarian cancer in Europe and the United States in 2014. Other PARP inhibitors under clinical trials include rucaparib, niraparib, veliparib, and the "PARP-trapping" BMN-673. BRCA1/2 sequencing is an FDA-approved companion diagnostics, which predicts the cancer vulnerability to PARP inhibition. Together, synthetic lethal PARP inhibition is a novel promising strategy for cancer intervention even in cases without prominent driver oncogenes. PMID:26281686

  20. [Pharmacology of bone resorption inhibitor].

    PubMed

    Menuki, Kunitaka; Sakai, Akinori

    2015-10-01

    Currently, bone resorption inhibitor is mainly used for osteoporosis. A number of these agents have been developed. These pharmacological action are various. Bisphosphonate inhibit functions of the osteoclasts by inducing apoptosis. On the one hand, RANK-ligand inhibitor and selective estrogen receptor modulator inhibit formation of osteoclasts. It is important to understand these pharmacological action for the selection of the appropriate medicine. PMID:26529923

  1. Corrosion inhibitor selection for wet pipelines

    SciTech Connect

    Buck, E.

    1995-12-31

    Selection of corrosion inhibitors for wet pipelines is based on laboratory testing and field confirmation. Both the use and selection of corrosion inhibitors are driven by economics. Economics of alternative corrosion protection methods is not treated in this paper, but the economics of proper inhibitor selection are. The key to successful inhibitor selection is careful analysis of pipeline flow conditions and experimental emulation of its corrosive environment. Transportation of inhibitor to the corroding interface must be explicitly considered in the emulation. Standard corrosion rate measurement methods are used to evaluate inhibitors. Inhibitor properties tabulated during evaluation form a core database for continuing quality control.

  2. [The synthesis of specific enzyme inhibitors].

    PubMed

    Iakovleva, G M

    1987-04-01

    The review deals with directed synthesis of specific enzyme inhibitors. They are classified within the framework of the mechanistic approach, namely, stable analogues of substrates, which form enzyme complexes mimicking the Michaelis complex or those which influence the chemical stages of enzyme catalysis; conformational inhibitors; substrate analogues participating in enzyme reactions and producing modified products; suicide inhibitors; stage inhibitors (inhibitors influencing certain stages of enzyme reaction); transition state analogues; multisubstrate analogues and collected substrates. Types of chemical modification used in synthesis of the specific inhibitors are discussed. Some possibilities of the quantity structure-activity relationship methods, computer modelling and molecular graphics in designing the optimal structure of inhibitors are mentioned. PMID:3300658

  3. Pharmacology of phosphodiesterase-5 inhibitors.

    PubMed

    Corbin, J D; Francis, S H

    2002-01-01

    The clinical properties (efficacy and safety profile) of a medicine are related not only to its mode of action, but also to its selectivity for its target (usually a receptor or enzyme) and are also influenced by its pharmacokinetic properties (absorption, distribution, metabolism and elimination). The growing number of phosphodiesterase inhibitors that are selective for phosphodiesterase-5 (PDE5) represent a promising new class of compounds that are useful for the treatment of erectile dysfunction and perhaps other disorders. Some of the basic pharmacodynamic and pharmacokinetic parameters that describe drug action are discussed with regard to the new PDE5 inhibitors. Central topics reviewed are the concentration that produces a given in vitro response, or potency (IC50), maximum plasma concentration (Cmax), time to Cmax (Tmax), half-life (t 1/2), area under the curve (AUC), bioavailability, onset and duration of action, and the balance to achieve optimum safety and efficacy. To illustrate these concepts, a group of inhibitors with varying selectivities and potencies for PDE5 (theophylline, IBMX, zaprinast, sildenafil, tadalafil and vardenafil) are discussed. Each drug has its own set of unique pharmacological characteristics based on its specific molecular structure, enzyme inhibition profile and pharmacokinetic properties. Each PDE5 inhibitor has a distinct selectivity that contributes to its safety profile. As with all new drugs, and especially those in a new class, careful evaluation will be necessary to ensure the optimal use of the PDE5 inhibitors. PMID:12166544

  4. Evolutionary families of peptidase inhibitors.

    PubMed Central

    Rawlings, Neil D; Tolle, Dominic P; Barrett, Alan J

    2004-01-01

    The proteins that inhibit peptidases are of great importance in medicine and biotechnology, but there has never been a comprehensive system of classification for them. Some of the terminology currently in use is potentially confusing. In the hope of facilitating the exchange, storage and retrieval of information about this important group of proteins, we now describe a system wherein the inhibitor units of the peptidase inhibitors are assigned to 48 families on the basis of similarities detectable at the level of amino acid sequence. Then, on the basis of three-dimensional structures, 31 of the families are assigned to 26 clans. A simple system of nomenclature is introduced for reference to each clan, family and inhibitor. We briefly discuss the specificities and mechanisms of the interactions of the inhibitors in the various families with their target enzymes. The system of families and clans of inhibitors described has been implemented in the MEROPS peptidase database (http://merops.sanger.ac.uk/), and this will provide a mechanism for updating it as new information becomes available. PMID:14705960

  5. Microbial inhibitors of cysteine proteases.

    PubMed

    Kędzior, Mateusz; Seredyński, Rafał; Gutowicz, Jan

    2016-08-01

    Cysteine proteases are one of the major classes of proteolytic enzymes involved in a number of physiological and pathological processes in plants, animals and microorganisms. When their synthesis, activity and localization in mammalian cells are altered, they may contribute to the development of many diseases, including rheumatoid arthritis, osteoporosis and cancer. Therefore, cysteine proteases have become promising drug targets for the medical treatment of these disorders. Inhibitors of cysteine proteases are also produced by almost every group of living organisms, being responsible for the control of intracellular proteolytic activity. Microorganisms synthesize cysteine protease inhibitors not only to regulate the activity of endogenous, often virulent enzymes, but also to hinder the host's proteolytic defense system and evade its immune responses against infections. Present work describes known to date microbial inhibitors of cysteine proteases in terms of their structure, enzyme binding mechanism, specificity and pathophysiological roles. The overview of both proteinaceous and small-molecule inhibitors produced by all groups of microorganisms (bacteria, archaea, fungi, protists) and viruses is provided. Subsequently, possible applications of microbial inhibitors in science, medicine and biotechnology are also highlighted. PMID:27048482

  6. Electrochemical studies of corrosion inhibitors

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    The effect of single salts, as well as multicomponent mixtures, on corrosion inhibition was studied for type 1010 steel; for 5052, 1100, and 2219-T87 aluminum alloys; and for copper. Molybdate-containing inhibitors exhibit an immediate, positive effect for steel corrosion, but an incubation period may be required for aluminum before the effect of a given inhibitor can be determined. The absence of oxygen was found to provide a positive effect (smaller corrosion rate) for steel and copper, but a negative effect for aluminum. This is attributed to the two possible mechanisms by which aluminum can oxidize. Corrosion inhibition is generally similar for oxygen-rich and oxygen-free environments. The results show that the electrochemical method is an effective means of screening inhibitors for the corrosion of single metals, with caution to be exercised in the case of aluminum.

  7. Positron emitter labeled enzyme inhibitors

    DOEpatents

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

    1987-05-22

    This invention involved a new strategy for imaging 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 in activators 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. 2 figs.

  8. Positron emitter labeled enzyme inhibitors

    DOEpatents

    Fowler, Joanna S.; MacGregor, Robert R.; Wolf, Alfred P.; Langstrom, Bengt

    1990-01-01

    This invention involves a new strategy for imaging 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.

  9. Corrosion inhibitors from expired drugs.

    PubMed

    Vaszilcsin, Nicolae; Ordodi, Valentin; Borza, Alexandra

    2012-07-15

    This paper presents a method of expired or unused drugs valorization as corrosion inhibitors for metals in various media. Cyclic voltammograms were drawn on platinum in order to assess the stability of pharmaceutically active substances from drugs at the metal-corrosive environment interface. Tafel slope method was used to determine corrosion rates of steel in the absence and presence of inhibitors. Expired Carbamazepine and Paracetamol tablets were used to obtain corrosion inhibitors. For the former, the corrosion inhibition of carbon steel in 0.1 mol L(-1) sulfuric acid solution was about 90%, whereas for the latter, the corrosion inhibition efficiency of the same material in the 0.25 mol L(-1) acetic acid-0.25 mol L(-1) sodium acetate buffer solution was about 85%. PMID:22561212

  10. Positron emitter labeled enzyme inhibitors

    SciTech Connect

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

    1990-04-03

    This invention involves a new strategy for imaging 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.

  11. Monoglyceride lipase: Structure and inhibitors.

    PubMed

    Scalvini, Laura; Piomelli, Daniele; Mor, Marco

    2016-05-01

    Monoglyceride lipase (MGL), the main enzyme responsible for the hydrolytic deactivation of the endocannabinoid 2-arachidonoyl-sn-glycerol (2-AG), is an intracellular serine hydrolase that plays critical roles in many physiological and pathological processes, such as pain, inflammation, neuroprotection and cancer. The crystal structures of MGL that are currently available provide valuable information about how this enzyme might function and interact with site-directed small-molecule inhibitors. On the other hand, its conformational equilibria and the contribution of regulatory cysteine residues present within the substrate-binding pocket or on protein surface remain open issues. Several classes of MGL inhibitors have been developed, from early reversible ones, such as URB602 and pristimerin, to carbamoylating agents that react with the catalytic serine, such as JZL184 and more recent O-hexafluoroisopropyl carbamates. Other inhibitors that modulate MGL activity by interacting with conserved regulatory cysteines act through mechanisms that deserve to be more thoroughly investigated. PMID:26216043

  12. STAT inhibitors for cancer therapy

    PubMed Central

    2013-01-01

    Signal Transducer and Activator of Transcription (STAT) proteins are a family of cytoplasmic transcription factors consisting of 7 members, STAT1 to STAT6, including STAT5a and STAT5b. STAT proteins are thought to be ideal targets for anti-cancer therapy since cancer cells are more dependent on the STAT activity than their normal counterparts. Inhibitors targeting STAT3 and STAT5 have been developed. These included peptidomimetics, small molecule inhibitors and oligonucleotides. This review summarized advances in preclinical and clinical development of these compounds. PMID:24308725

  13. SGLT2 inhibitors: new reports.

    PubMed

    2015-10-12

    A significant decrease in cardiovascular mortality has been reported with use of the SGLT2 inhibitor empagliflozin (Jardiance) to treat patients with type 2 diabetes who have established cardiovascular disease. The mechanism of this reduction is unclear, and these results may not apply to patients with type 2 diabetes and less advanced cardiovascular disease. Whether the increase in fractures reported with canagliflozin (Invokana) could also occur with empagliflozin remains to be established. All SGLT2 inhibitors are only modestly effective for treatment of diabetes. PMID:26445203

  14. Biocatalysts with enhanced inhibitor tolerance

    DOEpatents

    Yang, Shihui; Linger, Jeffrey; Franden, Mary Ann; Pienkos, Philip T.; Zhang, Min

    2015-12-08

    Disclosed herein are biocatalysts for the production of biofuels, including microorganisms that contain genetic modifications conferring tolerance to growth and fermentation inhibitors found in many cellulosic feedstocks. Methods of converting cellulose-containing materials to fuels and chemicals, as well as methods of fermenting sugars to fuels and chemicals, using these biocatalysts are also disclosed.

  15. Acetylcholinesterase Inhibitors: Pharmacology and Toxicology

    PubMed Central

    Čolović, Mirjana B; Krstić, Danijela Z; Lazarević-Pašti, Tamara D; Bondžić, Aleksandra M; Vasić, Vesna M

    2013-01-01

    Acetylcholinesterase is involved in the termination of impulse transmission by rapid hydrolysis of the neurotransmitter acetylcholine in numerous cholinergic pathways in the central and peripheral nervous systems. The enzyme inactivation, induced by various inhibitors, leads to acetylcholine accumulation, hyperstimulation of nicotinic and muscarinic receptors, and disrupted neurotransmission. Hence, acetylcholinesterase inhibitors, interacting with the enzyme as their primary target, are applied as relevant drugs and toxins. This review presents an overview of toxicology and pharmacology of reversible and irreversible acetylcholinesterase inactivating compounds. In the case of reversible inhibitors being commonly applied in neurodegenerative disorders treatment, special attention is paid to currently approved drugs (donepezil, rivastigmine and galantamine) in the pharmacotherapy of Alzheimer’s disease, and toxic carbamates used as pesticides. Subsequently, mechanism of irreversible acetylcholinesterase inhibition induced by organophosphorus compounds (insecticides and nerve agents), and their specific and nonspecific toxic effects are described, as well as irreversible inhibitors having pharmacological implementation. In addition, the pharmacological treatment of intoxication caused by organophosphates is presented, with emphasis on oxime reactivators of the inhibited enzyme activity administering as causal drugs after the poisoning. Besides, organophosphorus and carbamate insecticides can be detoxified in mammals through enzymatic hydrolysis before they reach targets in the nervous system. Carboxylesterases most effectively decompose carbamates, whereas the most successful route of organophosphates detoxification is their degradation by corresponding phosphotriesterases. PMID:24179466

  16. Less-toxic corrosion inhibitors

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1981-01-01

    Combinations of borates, nitrates, phosphates, silicates, and sodium MBT protect aluminum from corrosion in fresh water. Most effective combinations contained sodium phosphate and were alkaline. These inhibitors replace toxic chromates which are subject to governmental restrictions, but must be used in larger quantities. Experimental exposure times varied from 1 to 14 months depending upon nature of submersion solution.

  17. Aromatase Inhibitors and Other Compounds for Lowering Breast Cancer Risk

    MedlinePlus

    ... References Aromatase inhibitors and other compounds for lowering breast cancer risk Aromatase inhibitors (drugs that lower estrogen levels) ... day. Can aromatase inhibitors lower the risk of breast cancer? Aromatase inhibitors are used mainly to treat hormone ...

  18. Salicylanilide Inhibitors of Toxoplasma gondii

    PubMed Central

    Fomovska, Alina; Wood, Richard D.; Mui, Ernest; Dubey, Jitenter P.; Ferriera, Leandra R.; Hickman, Mark R.; Lee, Patricia J.; Leed, Susan E.; Auschwitz, Jennifer M.; Welsh, William J.; Sommerville, Caroline; Woods, Stuart; Roberts, Craig; McLeod, Rima

    2012-01-01

    Toxoplasma gondii(T. gondii) is an apicomplexan parasite that can cause eye disease, brain disease, and death, especially in congenitally infected and immune-compromised people. Novel medicines effective against both active and latent forms of the parasite are greatly needed. The current study focused on the discovery of such medicines by exploring a family of potential inhibitors whose anti-apicomplexan activity has not been previously reported. Initial screening efforts revealed that niclosamide, a drug approved for anthelmintic use, possessed promising activity in vitro against T. gondii. This observation inspired the evaluation of the activity of a series of salicylanilides and derivatives. Several inhibitors with activities in the nanomolar range with no appreciable in vitro toxicity to human cells were identified. An initial structure-activity relationship was explored. Four compounds were selected for evaluation in an in vivo model of infection, and two derivatives with potentially enhanced pharmacological parameters demonstrated the best activity profiles. PMID:22970937

  19. Macrocyclic compounds as corrosion inhibitors

    SciTech Connect

    Quraishi, M.A.; Rawat, J.; Ajmal, M.

    1998-12-01

    The influence of three macrocyclic compounds on corrosion of mild steel (MS) in hydrochloric acid (HCl) was investigated using weight loss, potentiodynamic polarization, alternating current (AC) impedance, and hydrogen permeation techniques. All the investigated compounds showed significant efficiencies and reduced permeation of hydrogen through MS in HCl. Inhibition efficiency (IE) varied with the nature and concentrations of the inhibitors, temperature, and concentrations of the acid solutions. The addition of iodide ions (I{sup {minus}}) increased IE of all the tested compounds as a result of the synergistic effect. Potentiodynamic polarization results revealed that macrocyclic compounds acted as mixed inhibitors in 1 M HCl to 5 M HCl. Adsorption on the metal surface obeyed Temkin`s adsorption isotherm. Auger electron spectroscopy (AES) of the polished MS surface, exposed with tetraphenyldithia-octaazacyclotetradeca-hexaene (PTAT) proved adsorption of this compound on the surface through nitrogen and sulfur atoms.

  20. [Proteasome inhibitors in cancer therapy].

    PubMed

    Romaniuk, Wioletta; Ołdziej, Agnieszka Ewa; Zińczuk, Justyna; Kłoczko, Janusz

    2015-01-01

    Proteasomes are multisubunit enzyme complexes. They contain three enzymatic active sites which are termed chymotrypsin-like, trypsin-like, and caspase-like. The elementary function of the proteasomes is degradation of damaged proteins. Proteasome inhibition leads to accumulation of damaged protein, which leads to caspase activation and cell death. This relationship is used in cancer therapy. Bortezomib is the first proteasome inhibitor approved by the US Food and Drug Administration for the treatment of relapsed/refractory multiple myeloma. Carfilzomib belongs to the second generation of drugs, which was approved by the US FDA in 2012. Currently in the study phase there are four new inhibitors: ixazomib (MLN9780/MLN2238), delanzomib (CEP-18770), oprozomib (ONX0912/PR-047) and marizomib (NPI-0052). PMID:27259216

  1. Thioredoxin Reductase and its Inhibitors

    PubMed Central

    Saccoccia, Fulvio; Angelucci, Francesco; Boumis, Giovanna; Carotti, Daniela; Desiato, Gianni; Miele, Adriana E; Bellelli, Andrea

    2014-01-01

    Thioredoxin plays a crucial role in a wide number of physiological processes, which span from reduction of nucleotides to deoxyriboucleotides to the detoxification from xenobiotics, oxidants and radicals. The redox function of Thioredoxin is critically dependent on the enzyme Thioredoxin NADPH Reductase (TrxR). In view of its indirect involvement in the above mentioned physio/pathological processes, inhibition of TrxR is an important clinical goal. As a general rule, the affinities and mechanisms of binding of TrxR inhibitors to the target enzyme are known with scarce precision and conflicting results abound in the literature. A relevant analysis of published results as well as the experimental procedures is therefore needed, also in view of the critical interest of TrxR inhibitors. We review the inhibitors of TrxR and related flavoreductases and the classical treatment of reversible, competitive, non competitive and uncompetitive inhibition with respect to TrxR, and in some cases we are able to reconcile contradictory results generated by oversimplified data analysis. PMID:24875642

  2. Carbonic anhydrase inhibitors drug design.

    PubMed

    McKenna, Robert; Supuran, Claudiu T

    2014-01-01

    Inhibition of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) has pharmacologic applications in the field of antiglaucoma, anticonvulsant, antiobesity, and anticancer agents but is also emerging for designing anti-infectives (antifungal and antibacterial agents) with a novel mechanism of action. As a consequence, the drug design of CA inhibitors (CAIs) is a very dynamic field. Sulfonamides and their isosteres (sulfamates/sulfamides) constitute the main class of CAIs which bind to the metal ion in the enzyme active site. Recently the dithiocarbamates, possessing a similar mechanism of action, were reported as a new class of inhibitors. Other families of CAIs possess a distinct mechanism of action: phenols, polyamines, some carboxylates, and sulfocoumarins anchor to the zinc-coordinated water molecule. Coumarins and five/six-membered lactones are prodrug inhibitors, binding in hydrolyzed form at the entrance of the active site cavity. Novel drug design strategies have been reported principally based on the tail approach for obtaining all these types of CAIs, which exploit more external binding regions within the enzyme active site (in addition to coordination to the metal ion), leading thus to isoform-selective compounds. Sugar-based tails as well as click chemistry were the most fruitful developments of the tail approach. Promising compounds that inhibit CAs from bacterial and fungal pathogens, of the dithiocarbamate, phenol and carboxylate types have also been reported. PMID:24146385

  3. Bromodomains and their pharmacological inhibitors.

    PubMed

    Gallenkamp, Daniel; Gelato, Kathy A; Haendler, Bernard; Weinmann, Hilmar

    2014-03-01

    Over 60 bromodomains belonging to proteins with very different functions have been identified in humans. Several of them interact with acetylated lysine residues, leading to the recruitment and stabilization of protein complexes. The bromodomain and extra-terminal domain (BET) proteins contain tandem bromodomains which bind to acetylated histones and are thereby implicated in a number of DNA-centered processes, including the regulation of gene expression. The recent identification of inhibitors of BET and non-BET bromodomains is one of the few examples in which effective blockade of a protein-protein interaction can be achieved with a small molecule. This has led to major strides in the understanding of the function of bromodomain-containing proteins and their involvement in diseases such as cancer and inflammation. Indeed, BET bromodomain inhibitors are now being clinically evaluated for the treatment of hematological tumors and have also been tested in clinical trials for the relatively rare BRD-NUT midline carcinoma. This review gives an overview of the newest developments in the field, with a focus on the biology of selected bromodomain proteins on the one hand, and on reported pharmacological inhibitors on the other, including recent examples from the patent literature. PMID:24497428

  4. Enhancing CHK1 inhibitor lethality in glioblastoma.

    PubMed

    Tang, Yong; Dai, Yun; Grant, Steven; Dent, Paul

    2012-04-01

    The present studies were initiated to determine whether inhibitors of MEK1/2 or SRC signaling, respectively, enhance CHK1 inhibitor lethality in primary human glioblastoma cells. Multiple MEK1/2 inhibitors (CI-1040 (PD184352); AZD6244 (ARRY-142886)) interacted with multiple CHK1 inhibitors (UCN-01, AZD7762) to kill multiple primary human glioma cell isolates that have a diverse set of genetic alterations typically found in the disease. Inhibition of SRC family proteins also enhanced CHK1 inhibitor lethality. Combined treatment of glioma cells with (MEK1/2 + CHK1) inhibitors enhanced radiosensitivity. Combined (MEK1/2 + CHK1) inhibitor treatment led to dephosphorylation of ERK1/2 and S6 ribosomal protein, whereas the phosphorylation of JNK and p38 was increased. MEK1/2 + CHK1 inhibitor-stimulated cell death was associated with the cleavage of pro-caspases 3 and 7 as well as the caspase substrate (PARP). We also observed activation of pro-apoptotic BCL-2 effector proteins BAK and BAX and reduced levels of pro-survival BCL-2 family protein BCL-XL. Overexpression of BCL-XL alleviated but did not completely abolish MEK1/2 + CHK1 inhibitor cytotoxicity in GBM cells. These findings argue that multiple inhibitors of the SRC-MEK pathway have the potential to interact with multiple CHK1 inhibitors to kill glioma cells. PMID:22313687

  5. The burden of inhibitors in haemophilia patients.

    PubMed

    Walsh, Christopher E; Jiménez-Yuste, Víctor; Auerswald, Guenter; Grancha, Salvador

    2016-08-31

    The burden of disease in haemophilia patients has wide ranging implications for the family and to society. There is evidence that having a current inhibitor increases the risk of morbidity and mortality. Morbidity is increased by the inability to treat adequately and its consequent disabilities, which then equates to a poor quality of life compared with non-inhibitor patients. The societal cost of care, or `burden of inhibitors', increases with the ongoing presence of an inhibitor. Therefore, it is clear that successful eradication of inhibitors by immune tolerance induction (ITI) is the single most important milestone one can achieve in an inhibitor patient. The type of factor VIII (FVIII) product used in ITI regimens varies worldwide. Despite ongoing debate, there is in vitro and retrospective clinical evidence to support the use of plasma-derived VWF-containing FVIII concentrates in ITI regimens in order to achieve early and high inhibitor eradication success rates. PMID:27528280

  6. Impact of simultaneous stimulation of 5-lipoxygenase and myeloperoxidase in human neutrophils.

    PubMed

    Zschaler, Josefin; Arnhold, Jürgen

    2016-04-01

    Human neutrophil 5-lipoxygenase (5-LOX) oxidizes arachidonic acid (AA) to 5S-hydro(pero)xy-6E,8Z,11Z, 14Z-eicosatetraenoic acid (5-H(p)ETE) and leukotriene (LT)A4, which is further converted to the chemoattractant LTB4. These cells contain also the heme enzyme myeloperoxidase (MPO) producing several potent oxidants such as hypochlorous acid (HOCl). Previously, it was shown that MPO-metabolites influence 5-LOX product formation. Here, we addressed the question, whether a simultaneous activation of MPO and 5-LOX in neutrophils results in comparable changes of 5-LOX activity. Human neutrophils were stimulated with H2O2 or phorbol 12-myristate 13-acetate (PMA) for MPO activation and subsequently treated with calcium ionophore A23187 inducing 5-LOX product formation on endogenous AA. Special attention was drawn to neutrophil vitality, formation of MPO-derived metabolites and redox status. The pre-stimulation with H2O2 resulted in a concentration-dependent increase in the ratio of 5-HETE to the sum of LTB4+6-trans-LTB4 in consequence of MPO activation. Thereby no impairment of cell vitality and only a slightly reduction of total glutathione level was observed. An influence of MPO on 5-LOX product formation could be suggested using an MPO inhibitor. In contrast, the pre-stimulation with PMA resulted in different changes of 5-LOX product formation leading to a reduced amount of 5-HETE unaffected by MPO inhibition. Furthermore, impaired cell vitality and diminished redox status was detected after PMA stimulation. Nevertheless, a MPO-induced diminution of LTB4 was obvious. Further work is necessary to define the type of 5-LOX modification and investigate the effect of physiological MPO activators. PMID:27033421

  7. Xylanase inhibitors bind to nonstarch polysaccharides.

    PubMed

    Fierens, Ellen; Gebruers, Kurt; Courtin, Christophe M; Delcour, Jan A

    2008-01-23

    This study is an in-depth investigation of the interaction between polysaccharides and the proteinaceous xylanase inhibitors, Triticum aestivum xylanase inhibitor (TAXI), xylanase inhibitor protein (XIP), and thaumatin-like xylanase inhibitor (TLXI). The binding affinities of all three known types of xylanase inhibitors from wheat are studied by measuring the residual xylanase inhibition activity after incubation of the inhibitors in the presence of different polysaccharides, such as beta-glucans and (arabino)xylans. The binding affinities of all three xylanase inhibitors for (arabino)xylans increased with a decreasing arabinose/xylose ratio (A/X ratio). This phenomenon was observed both with water-extractable and water-unextractable (arabino)xylans. The inhibitors also interacted with different soluble and insoluble beta-glucans. None of the inhibitors tested had the ability to hydrolyze the polysaccharides investigated. The present findings contribute to the unraveling of the function of xylanase inhibitors in nature and to the prediction of the effect of added xylanases in cereal-based biotechnological processes, such as bread making and gluten-starch separation. PMID:18092758

  8. Biomarkers associated with checkpoint inhibitors.

    PubMed

    Manson, G; Norwood, J; Marabelle, A; Kohrt, H; Houot, R

    2016-07-01

    Checkpoint inhibitors (CPI), namely anti-CTLA4 and anti-PD1/PD-L1 antibodies, demonstrated efficacy across multiple types of cancer. However, only subgroups of patients respond to these therapies. Additionally, CPI can induce severe immune-related adverse events (irAE). Biomarkers that predict efficacy and toxicity may help define the patients who may benefit the most from these costly and potentially toxic therapies. In this study, we review the main biomarkers that have been associated with the efficacy (pharmacodynamics and clinical benefit) and the toxicity (irAE) of CPIs in patients. PMID:27122549

  9. Monoamine Oxidase Inhibitors: Clinical Review

    PubMed Central

    Remick, Ronald A.; Froese, Colleen

    1990-01-01

    Monoamine oxidase inhibitors (MAOIs) are effective antidepressant agents. They are increasingly and effectively used in a number of other psychiatric and non-psychiatric medical syndromes. Their potential for serious toxicity (i.e., hypertensive reaction) is far less than original reports suggest, and newer reversible substrate-specific MAOIs may offer even less toxicity. The author reviews the pharmacology, mechanism of action, clinical indications, and dosing strategies of MAOIs. The common MAOI side-effects (hypotension, weight gain, sexual dysfunction, insomnia, daytime sedation, myoclonus, and hypertensive episodes) are described and management techniques suggested. Recent clinical developments involving MAOIs are outlined. PMID:21233984

  10. Oligopeptide cyclophilin inhibitors: a reassessment.

    PubMed

    Schumann, Michael; Jahreis, Günther; Kahlert, Viktoria; Lücke, Christian; Fischer, Gunter

    2011-11-01

    Potent cyclophilin A (CypA) inhibitors such as non-immunosuppressive cyclosporin A (CsA) derivatives have been already used in clinical trials in patients with viral infections. CypA is a peptidyl prolyl cis/trans isomerase (PPIase) that catalyzes slow prolyl bond cis/trans interconversions of the backbone of substrate peptides and proteins. In this study we investigate whether the notoriously low affinity inhibitory interaction of linear proline-containing peptides with the active site of CypA can be increased through a combination of a high cis/trans ratio and a negatively charged C-terminus as has been recently reported for Trp-Gly-Pro. Surprisingly, isothermal titration calorimetry did not reveal formation of an inhibitory CypA/Trp-Gly-Pro complex previously described within a complex stability range similar to CsA, a nanomolar CypA inhibitor. Moreover, despite of cis content of 41% at pH 7.5 Trp-Gly-Pro cannot inhibit CypA-catalyzed standard substrate isomerization up to high micromolar concentrations. However, in the context of the CsA framework a net charge of -7 clustered at the amino acid side chain of position 1 resulted in slightly improved CypA inhibition. PMID:21963115

  11. New proteasome inhibitors in myeloma.

    PubMed

    Lawasut, Panisinee; Chauhan, Dharminder; Laubach, Jacob; Hayes, Catriona; Fabre, Claire; Maglio, Michelle; Mitsiades, Constantine; Hideshima, Teru; Anderson, Kenneth C; Richardson, Paul G

    2012-12-01

    Proteasome inhibition has a validated role in cancer therapy since the successful introduction of bortezomib for the treatment of multiple myeloma (MM) and mantle cell lymphoma, leading to the development of second-generation proteasome inhibitors (PI) for MM patients in whom currently approved therapies have failed. Five PIs have reached clinical evaluation, with the goals of improving efficacy and limiting toxicity, including peripheral neuropathy (PN). Carfilzomib, an epoxyketone with specific chymothrypsin-like activity, acts as an irreversible inhibitor and was recently FDA approved for the response benefit seen in relapsed and refractory MM patients previously treated with bortezomib, thalidomide and lenalidomide. ONX-0912 is now under evaluation as an oral form with similar activity. The boronate peptides MLN9708 and CEP-18770 are orally bioactive bortezomib analogs with prolonged activity and greater tissue penetration. NPI-0052 (marizomib) is a unique, beta-lactone non-selective PI that has been shown to potently overcome bortezomib resistance in vitro. All of these second-generation PIs demonstrate encouraging anti-MM activity and appear to reduce the incidence of PN, with clinical trials ongoing. PMID:23065395

  12. New sulfur-containing corrosion inhibitor

    SciTech Connect

    Prince, P.

    2000-04-01

    No corrosion inhibitor available today is ideal in every way, but a new class of sulfur-containing compounds promises to address many field requirements. This article describes the performance characteristics of these compounds and discusses possible inhibition mechanisms. The emphasis in this work was on better understanding corrosion inhibition by sulfur-containing inhibitors under high shear-stress conditions, with special focus on localized (pitting) corrosion. The results indicate that the new sulfur-containing inhibitors (e.g., mercaptoalcohol [MA]) could be more effective in the field than currently available inhibitors.

  13. Simultaneous exposure of transformed cells to SRC family inhibitors and CHK1 inhibitors causes cell death.

    PubMed

    Mitchell, Clint; Hamed, Hossein A; Cruickshanks, Nichola; Tang, Yong; Bareford, M Danielle; Hubbard, Nissan; Tye, Gary; Yacoub, Adly; Dai, Yun; Grant, Steven; Dent, Paul

    2011-08-01

    The present studies were initiated to determine in greater molecular detail the regulation of CHK1 inhibitor lethality in transfected and infected breast cancer cells and using genetic models of transformed fibrobalsts. Multiple MEK1/2 inhibitors (PD184352, AZD6244 (ARRY-142886)) interacted with multiple CHK1 inhibitors (UCN-01 (7-hydroxystaurosporine), AZD7762) to kill mammary carcinoma cells and transformed fibroblasts. In transformed cells, CHK1 inhibitor -induced activation of ERK1/2 was dependent upon activation of SRC family non-receptor tyrosine kinases as judged by use of multiple SRC kinase inhibitors (PP2, Dasatinib; AZD0530), use of SRC/FYN/YES deleted transformed fibroblasts or by expression of dominant negative SRC. Cell killing by SRC family kinase inhibitors and CHK1 inhibitors was abolished in BAX/BAK -/- transformed fibroblasts and suppressed by over expression of BCL-XL. Treatment of cells with BCL-2/BCL-XL antagonists promoted SRC inhibitor + CHK1 inhibitor -induced lethality in a BAX/BAK-dependent fashion. Treatment of cells with [SRC + CHK1] inhibitors radio-sensitized tumor cells. These findings argue that multiple inhibitors of the SRC-RAS-MEK pathway interact with multiple CHK1 inhibitors to kill transformed cells. PMID:21642769

  14. Controlling CO{sub 2} corrosion with inhibitors

    SciTech Connect

    Dougherty, J.A.

    1998-12-31

    Transport of corrosion inhibitor to the location where they are needed is one of the primary concerns in the use of corrosion inhibitors. Two different types of inhibitors for controlling CO{sub 2} corrosion in gas well wellheads and flowlines are used as examples. In one example, the inhibitor forms a micelle in water which assists in the transport of inhibitor to the metal surface . In the other example, the inhibitor is readily dispersible in the water phase but must be stirred to ensure transport of the inhibitor to the metal surface. Field monitored corrosion rates using continuous application of inhibitor are presented for both types of inhibitor.

  15. Glycine Transporters and Their Inhibitors

    NASA Astrophysics Data System (ADS)

    Gilfillan, Robert; Kerr, Jennifer; Walker, Glenn; Wishart, Grant

    Glycine plays a ubiquitous role in many biological processes. In the central nervous system it serves as an important neurotransmitter acting as an agonist at strychnine-sensitive glycine receptors and as an essential co-agonist with glutamate at the NMDA receptor complex. Control of glycine concentrations in the vicinity of these receptors is mediated by the specific glycine transporters, GlyT1 and GlyT2. Inhibition of these transporters has been postulated to be of potential benefit in several therapeutic indications including schizophrenia and pain. In this review we discuss our current knowledge of glycine transporters and focus on recent advances in the medicinal chemistry of GlyT1 and GlyT2 inhibitors.

  16. KH-30 Parafin Inhibitor Treatment

    SciTech Connect

    Rochelle, J.

    2001-09-30

    United Energy Corporation (UNRG) and the U.S. Department of Energy personnel tested KH-30 at the Rocky Mountain Oilfield Testing Center (RMOTC) outside Casper, Wyoming on two separate occasions. KH-30 is a non-toxic, non-hazardous product, which combines the functions of a solvent dispersant, crystal modifier and inhibitor into a single solution. The first test was held in March of 2001, wherein five wells were treated with a mixture of KH-30 and brine water, heated to 180 degrees F. No increase in production was attained in these tests. In June, 2001, three shallow, low pressure RMOTC wells with 30 years of production were treated with a mixture of 40% KH-30 and 60% diesel. Increases were seen in three wells. The wells then returned to their original rates.

  17. Natural Products as Aromatase Inhibitors

    PubMed Central

    Balunas, Marcy J.; Su, Bin; Brueggemeier, Robert W.; Kinghorn, A. Douglas

    2010-01-01

    With the clinical success of several synthetic aromatase inhibitors (AIs) in the treatment of postmenopausal estrogen receptor-positive breast cancer, researchers have also been investigating also the potential of natural products as AIs. Natural products from terrestrial and marine organisms provide a chemically diverse array of compounds not always available through current synthetic chemistry techniques. Natural products that have been used traditionally for nutritional or medicinal purposes (e.g., botanical dietary supplements) may also afford AIs with reduced side effects. A thorough review of the literature regarding natural product extracts and secondary metabolites of plant, microbial, and marine origin that have been shown to exhibit aromatase inhibitory activity is presented herein. PMID:18690828

  18. Loratadine analogues as MAGL inhibitors.

    PubMed

    Patel, Jayendra Z; Ahenkorah, Stephen; Vaara, Miia; Staszewski, Marek; Adams, Yahaya; Laitinen, Tuomo; Navia-Paldanius, Dina; Parkkari, Teija; Savinainen, Juha R; Walczyński, Krzysztof; Laitinen, Jarmo T; Nevalainen, Tapio J

    2015-04-01

    Compound 12a (JZP-361) acted as a potent and reversible inhibitor of human recombinant MAGL (hMAGL, IC50=46 nM), and was found to have almost 150-fold higher selectivity over human recombinant fatty acid amide hydrolase (hFAAH, IC50=7.24 μM) and 35-fold higher selectivity over human α/β-hydrolase-6 (hABHD6, IC50=1.79 μM). Additionally, compound 12a retained H1 antagonistic affinity (pA2=6.81) but did not show cannabinoid receptor activity, when tested at concentrations ⩽ 10 μM. Hence, compound 12a represents a novel dual-acting pharmacological tool possessing both MAGL-inhibitory and antihistaminergic activities. PMID:25752982

  19. Inhibitors of apoptosis catch ubiquitin.

    PubMed

    Rajalingam, Krishnaraj; Dikic, Ivan

    2009-01-01

    IAP (inhibitor of apoptosis) proteins are a class of anti-apoptotic regulators characterized by the presence of BIR (baculoviral IAP repeat) domains. Some of the IAPs also possess a RING (really interesting new gene) domain with E3 ubiquitin ligase activity. In this issue of the Biochemical Journal, Blankenship et al. unveil the presence of an UBA (ubiquitin-associated domain) in several IAPs. UBAs in c-IAPs (cellular IAPs) bind to monoubiquitin and ubiquitin chains and are implicated in degradation of c-IAPs by promoting their interaction with proteasomes as well as in regulation of TNF-alpha (tumour necrosis factor-alpha)-induced apoptosis. These novel observations establish IAPs as ubiquitin-interacting proteins and opens up new lines of investigation. PMID:19061481

  20. Quinolone-based HDAC inhibitors.

    PubMed

    Balasubramanian, Gopalan; Kilambi, Narasimhan; Rathinasamy, Suresh; Rajendran, Praveen; Narayanan, Shridhar; Rajagopal, Sridharan

    2014-08-01

    HDAC inhibitors emerged as promising drug candidates in combating wide variety of cancers. At present, two of the compounds SAHA and Romidepsin were approved by FDA for cutaneous T-cell lymphoma and many are in various clinical phases. A new quinolone cap structure was explored with hydroxamic acid as zinc-binding group (ZBG). The pan HDAC inhibitory and antiproliferative activities against three human cancer cell lines HCT-116 (colon), NCI-H460 (lung) and U251 (glioblastoma) of the compounds (4a-4w) were evaluated. Introduction of heterocyclic amines in CAP region increased the enzyme inhibitory and antiproliferative activities and few of the compounds tested are metabolically stable in both MLM and HLM. PMID:25019596

  1. The direct thrombin inhibitor hirudin.

    PubMed

    Greinacher, Andreas; Warkentin, Theodore E

    2008-05-01

    This review discusses the pharmacology and clinical applications of hirudin, a bivalent direct thrombin inhibitor (DTI). Besides the current major indication for hirudin--anticoagulation of patients with heparin-induced thrombocytopenia (HIT)--the experience with hirudin in other indications, especially acute coronary syndromes, are briefly presented. Hirudins have been formally studied prior to their regulatory approval; however, important information on their side effects and relevant preventative measures only became available later. Therefore, current recommendations and dosing schedules for hirudin differ considerably from the information given in the package inserts. Drawbacks of hirudin and important precautions for avoiding potential adverse effects are discussed in detail in the third part of this review. PMID:18449411

  2. Enzyme-Inhibitor Association Thermodynamics

    PubMed Central

    Resat, Haluk; Marrone, Tami J.; McCammon, J. Andrew

    1997-01-01

    Studying the thermodynamics of biochemical association reactions at the microscopic level requires efficient sampling of the configurations of the reactants and solvent as a function of the reaction pathways. In most cases, the associating ligand and receptor have complementary interlocking shapes. Upon association, loosely connected or disconnected solvent cavities at and around the binding site are formed. Disconnected solvent regions lead to severe statistical sampling problems when simulations are performed with explicit solvent. It was recently proposed that, when such limitations are encountered, they might be overcome by the use of the grand canonical ensemble. Here we investigate one such case and report the association free energy profile (potential of mean force) between trypsin and benzamidine along a chosen reaction coordinate as calculated using the grand canonical Monte Carlo method. The free energy profile is also calculated for a continuum solvent model using the Poisson equation, and the results are compared to the explicit water simulations. The comparison shows that the continuum solvent approach is surprisingly successful in reproducing the explicit solvent simulation results. The Monte Carlo results are analyzed in detail with respect to solvation structure. In the binding site channel there are waters bridging the carbonyl oxygen groups of Asp189 with the NH2 groups of benzamidine, which are displaced upon inhibitor binding. A similar solvent-bridging configuration has been seen in the crystal structure of trypsin complexed with bovine pancreatic trypsin inhibitor. The predicted locations of other internal waters are in very good agreement with the positions found in the crystal structures, which supports the accuracy of the simulations. ImagesFIGURE 5 PMID:9017183

  3. Intellectual property issues of immune checkpoint inhibitors.

    PubMed

    Storz, Ulrich

    2016-01-01

    Immune checkpoint inhibitors are drugs that interfere with tumor escape responses. Some members of this class are already approved, and expected to be blockbusters in the future. Many companies have developed patent activities in this field. This article focuses on the patent landscape, and discusses key players and cases related to immune checkpoint inhibitors. PMID:26466763

  4. Trypsin inhibitors for the treatment of pancreatitis.

    PubMed

    Brandl, Trixi; Simic, Oliver; Skaanderup, Philip R; Namoto, Kenji; Berst, Frederic; Ehrhardt, Claus; Schiering, Nikolaus; Mueller, Irene; Woelcke, Julian

    2016-09-01

    Proline-based trypsin inhibitors occupying the S1-S2-S1' region were identified by an HTS screening campaign. It was discovered that truncation of the P1' moiety and appropriate extension into the S4 region led to highly potent trypsin inhibitors with excellent selectivity against related serine proteases and a favorable hERG profile. PMID:27476144

  5. Aminofurazans as potent inhibitors of AKT kinase

    SciTech Connect

    Rouse, Meagan B.; Seefeld, Mark A.; Leber, Jack D.; McNulty, Kenneth C.; Sun, Lihui; Miller, William H.; Zhang, ShuYun; Minthorn, Elisabeth A.; Concha, Nestor O.; Choudhry, Anthony E.; Schaber, Michael D.; Heerding, Dirk A.

    2009-06-24

    AKT inhibitors containing an imidazopyridine aminofurazan scaffold have been optimized. We have previously disclosed identification of the AKT inhibitor GSK690693, which has been evaluated in clinical trials in cancer patients. Herein we describe recent efforts focusing on investigating a distinct region of this scaffold that have afforded compounds (30 and 32) with comparable activity profiles to that of GSK690693.

  6. Discovery and SAR of hydantoin TACE inhibitors

    SciTech Connect

    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.

    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.

  7. Tyrosinase inhibitors from Bolivian medicinal plants.

    PubMed

    Kubo, I; Yokokawa, Y; Kinst-Hori, I

    1995-05-01

    Bioassay-guided fractionation monitored by mushroom tyrosinase (EC 1.14.18.1) activity, afforded six inhibitors from three Bolivian medicinal plants, Buddleia coriacea, Gnaphalium cheiranthifolium, and Scheelea princeps. These inhibitors, which are all known phenolic compounds, inhibited the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) mediated by a mushroom tyrosinase. PMID:7623048

  8. The therapeutic potential of microbial proteasome inhibitors.

    PubMed

    Momose, Isao; Kawada, Manabu

    2016-08-01

    The proteasome influences cellular homeostasis through the degradation of regulatory proteins, many of which are also involved in disease pathogenesis. In particular, numerous regulatory proteins associated with tumor growth, such as cyclins, cyclin-dependent kinase inhibitors, tumor suppressors, and NF-κB inhibitors are degraded by the proteasome. Proteasome inhibitors can stabilize these regulatory proteins, resulting in the suppression of tumor development and the regulation of immune responses. Thus, proteasome inhibitors are promising candidate antitumor agents and immune-regulatory agents. Bortezomib is the first-in-class proteasome inhibitor approved for the treatment of multiple myeloma. Despite its high efficiency, however, a large proportion of patients do not attain sufficient clinical response due to toxicity and drug resistance. Therefore, the development of new proteasome inhibitors with improved pharmacological properties is needed. Natural products produced by microorganisms are a promising source of such compounds. This review provides an overview of proteasome inhibitors produced by microorganisms, with special focus on inhibitors isolated from actinomycetes. PMID:26589840

  9. Synthesis and biological evaluation of salicylic acid and N-acetyl-2-carboxybenzenesulfonamide regioisomers possessing a N-difluoromethyl-1,2-dihydropyrid-2-one pharmacophore: dual inhibitors of cyclooxygenases and 5-lipoxygenase with anti-inflammatory activity.

    PubMed

    Chowdhury, Morshed A; Abdellatif, Khaled R A; Dong, Ying; Das, Dipankar; Yu, Gang; Velázquez, Carlos A; Suresh, Mavanur R; Knaus, Edward E

    2009-12-15

    A novel class of salicylic acid and N-acetyl-2-carboxybenzenesulfonamide regioisomers possessing a N-difluoromethyl-1,2-dihydropyrid-2-one pharmacophore attached to its C-4 or C-5 position was designed for evaluation as anti-inflammatory (AI) agents. Replacement of the 2,4-difluorophenyl ring in diflunisal by the N-difluoromethyl-1,2-dihydropyrid-2-one moiety provided compounds showing dual selective cyclooxygenase-2 (COX-2)/5-lipoxygenase (5-LOX) inhibitory activities. AI structure-activity studies showed that the C-4 (14a) and C-5 (14b) salicylate regioisomers were 1.4- and 1.6-fold more potent than aspirin, and the C-5 N-acetyl-2-carboxybenzenesulfonamide regioisomer (22b) was 1.3- and 2.8-fold more potent than ibuprofen and aspirin, respectively. In vivo ulcer index (UI) studies showed that the 4- and 5-(N-difluoromethyl-1,2-dihydropyrid-2-one-4-yl)salicylic acids (14a and 14b) were completely non-ulcerogenic since no gastric lesions were present (UI=0) relative to aspirin (UI=57) at an equivalent mumol/kg oral dose. The N-difluoromethyl-1,2-dihydropyridin-2-one moiety provides a novel 5-LOX pharmacophore for the design of cyclic hydroxamic mimetics for exploitation in the development of dual COX-2/5-LOX inhibitory AI drugs. PMID:19884005

  10. [Recent development of selective cyclooxygenase-2 inhibitors].

    PubMed

    Kawai, Shinichi

    2002-12-01

    Nonsteroidal anti-inflammatory drugs(NSAIDs) are clinically effective against the inflammatory symptoms of rheumatoid arthritis. Recent attention has been focused on selective cyclooxygenase(COX)-2 inhibitors, a type of NSAID that inhibits a subtype of COX. Because of the different actions of COX-1 and COX-2, selective COX-2 inhibitors were expected to reduce adverse reactions such as gastrointestinal disorders. Various clinical studies have confirmed that the efficacy of COX-2 inhibitors for RA is similar to that of conventional NSAIDs, but they cause fewer severe gastrointestinal disorders. The incidence of complications related to renal dysfunction, such as edema and hypertension, is not different. Patients using selective COX-2 inhibitors have recently been reported to show an increase in thrombotic complications such as myocardial infarction. Therefore, more data on adverse events should be collected in the future from large-scale clinical studies to further clarify the actual value of selective COX-2 inhibitors. PMID:12510364

  11. Current acetylcholinesterase-inhibitors: a neuroinformatics perspective.

    PubMed

    Shaikh, Sibhghatulla; Verma, Anupriya; Siddiqui, Saimeen; Ahmad, Syed S; Rizvi, Syed M D; Shakil, Shazi; Biswas, Deboshree; Singh, Divya; Siddiqui, Mohmmad H; Shakil, Shahnawaz; Tabrez, Shams; Kamal, Mohammad A

    2014-04-01

    This review presents a concise update on the inhibitors of the neuroenzyme, acetylcholinesterase (AChE; EC 3.1.1.7). AChE is a serine protease, which hydrolyses the neurotransmitter, acetylcholine into acetate and choline thereby terminating neurotransmission. Molecular interactions (mode of binding to the target enzyme), clinical applications and limitations have been summarized for each of the inhibitors discussed. Traditional inhibitors (e.g. physostigmine, tacrine, donepezil, rivastigmine etc.) as well as novel inhibitors like various physostigmine-derivatives have been covered. This is followed by a short glimpse on inhibitors derived from nature (e.g. Huperzine A and B, Galangin). Also, a discussion on 'hybrid of pre-existing drugs' has been incorporated. Furthermore, current status of therapeutic applications of AChEinhibitors has also been summarized. PMID:24059296

  12. Pharmacological inhibitors of cyclin-dependent kinases.

    PubMed

    Knockaert, Marie; Greengard, Paul; Meijer, Laurent

    2002-09-01

    Cyclin-dependent kinases (CDKs) regulate the cell division cycle, apoptosis, transcription and differentiation in addition to functions in the nervous system. Deregulation of CDKs in various diseases has stimulated an intensive search for selective pharmacological inhibitors of these kinases. More than 50 inhibitors have been identified, among which >20 have been co-crystallized with CDK2. These inhibitors all target the ATP-binding pocket of the catalytic site of the kinase. The actual selectivity of most known CDK inhibitors, and thus the underlying mechanism of their cellular effects, is poorly known. Pharmacological inhibitors of CDKs are currently being evaluated for therapeutic use against cancer, alopecia, neurodegenerative disorders (e.g. Alzheimer's disease, amyotrophic lateral sclerosis and stroke), cardiovascular disorders (e.g. atherosclerosis and restenosis), glomerulonephritis, viral infections (e.g. HCMV, HIV and HSV) and parasitic protozoa (Plasmodium sp. and Leishmania sp.). PMID:12237154

  13. A Spider-Derived Kunitz-Type Serine Protease Inhibitor That Acts as a Plasmin Inhibitor and an Elastase Inhibitor

    PubMed Central

    Wan, Hu; Lee, Kwang Sik; Kim, Bo Yeon; Zou, Feng Ming; Yoon, Hyung Joo; Je, Yeon Ho; Li, Jianhong; Jin, Byung Rae

    2013-01-01

    Kunitz-type serine protease inhibitors are involved in various physiological processes, such as ion channel blocking, blood coagulation, fibrinolysis, and inflammation. While spider-derived Kunitz-type proteins show activity in trypsin or chymotrypsin inhibition and K+ channel blocking, no additional role for these proteins has been elucidated. In this study, we identified the first spider (Araneus ventricosus) Kunitz-type serine protease inhibitor (AvKTI) that acts as a plasmin inhibitor and an elastase inhibitor. AvKTI possesses a Kunitz domain consisting of a 57-amino-acid mature peptide that displays features consistent with Kunitz-type inhibitors, including six conserved cysteine residues and a P1 lysine residue. Recombinant AvKTI, expressed in baculovirus-infected insect cells, showed a dual inhibitory activity against trypsin (Ki 7.34 nM) and chymotrypsin (Ki 37.75 nM), defining a role for AvKTI as a spider-derived Kunitz-type serine protease inhibitor. Additionally, AvKTI showed no detectable inhibitory effects on factor Xa, thrombin, or tissue plasminogen activator; however, AvKTI inhibited plasmin (Ki 4.89 nM) and neutrophil elastase (Ki 169.07 nM), indicating that it acts as an antifibrinolytic factor and an antielastolytic factor. These findings constitute molecular evidence that AvKTI acts as a plasmin inhibitor and an elastase inhibitor and also provide a novel view of the functions of a spider-derived Kunitz-type serine protease inhibitor. PMID:23308198

  14. COX, LOX and platelet aggregation inhibitory properties of Lauraceae neolignans.

    PubMed

    Coy, Ericsson David; Cuca, Luis Enrique; Sefkow, Michael

    2009-12-15

    The anti-inflammatory potential of 26 neolignans (14 of the bicyclooctane-type and 12 of the benzofuran-type), isolated from three Lauraceae species (Pleurothyrium cinereum, Ocotea macrophylla and Nectandra amazonum), was evaluated in vitro through inhibition of COX-1, COX-2, 5-LOX and agonist-induced aggregation of rabbit platelets. Benzofuran neolignans were found to be selective COX-2 inhibitors, whereas bicyclooctane neolignans inhibit selectively the PAF-action as well as COX-1 and 5-LOX. The neolignan 9-nor-7,8-dehydro-isolicarin B 15 and cinerin C 7 were found to be the most potent COX-2 inhibitor and PAF-antagonist, respectively. Nectamazin C 10 exhibited dual 5-LOX/COX-2 inhibition. PMID:19880317

  15. High-affinity Cyclic Peptide Matriptase Inhibitors*

    PubMed Central

    Quimbar, Pedro; Malik, Uru; Sommerhoff, Christian P.; Kaas, Quentin; Chan, Lai Y.; Huang, Yen-Hua; Grundhuber, Maresa; Dunse, Kerry; Craik, David J.; Anderson, Marilyn A.; Daly, Norelle L.

    2013-01-01

    The type II transmembrane serine protease matriptase is a key activator of multiple signaling pathways associated with cell proliferation and modification of the extracellular matrix. Deregulated matriptase activity correlates with a number of diseases, including cancer and hence highly selective matriptase inhibitors may have therapeutic potential. The plant-derived cyclic peptide, sunflower trypsin inhibitor-1 (SFTI-1), is a promising drug scaffold with potent matriptase inhibitory activity. In the current study we have analyzed the structure-activity relationships of SFTI-1 and Momordica cochinchinensis trypsin inhibitor-II (MCoTI-II), a structurally divergent trypsin inhibitor from Momordica cochinchinensis that also contains a cyclic backbone. We show that MCoTI-II is a significantly more potent matriptase inhibitor than SFTI-1 and that all alanine mutants of both peptides, generated using positional scanning mutagenesis, have decreased trypsin affinity, whereas several mutations either maintain or result in enhanced matriptase inhibitory activity. These intriguing results were used to design one of the most potent matriptase inhibitors known to date with a 290 pm equilibrium dissociation constant, and provide the first indication on how to modulate affinity for matriptase over trypsin in cyclic peptides. This information might be useful for the design of more selective and therapeutically relevant inhibitors of matriptase. PMID:23548907

  16. Current use of phosphodiesterase inhibitors in urology

    PubMed Central

    Hakky, Tariq Said; Jain, Lakshay

    2015-01-01

    The causes of male erectile dysfunction (ED) are quite variable and are now commonly divided into etiologies such as ischemia, smooth muscle damage, or altered blood flow. Although varying rates of ED have been reported in literature, the number of men with ED is projected to increase worldwide by 2025 to approximately 322 million. Since the introduction of phosphodiesterase 5 (PDE5) inhibitors, there has been a paradigm shift in the treatment of ED because PDE5 inhibitors address a broad spectrum of etiologies for ED. Today, the American Urological Association recommends the use of three PDE5 inhibitors (sildenafil, tadalafil, and vardenafil) as a first-line therapy for the treatment of ED. This review evaluates the pharmacological mechanism of PDE5 inhibitors along with the impact and use of sildenafil, vardenafil, tadalafil, and avanafil. By increasing intracellular cGMP levels, PDE5 inhibitors have been shown to be effective in the treatment of ED. Through their effects on other cellular signaling pathways, PDE5 inhibitors have the potential for treating other urologic conditions as well. The use of PDE5 inhibitors can also be combined to produce a synergistic effect in conditions such as male hypogonadism and benign prostatic hyperplasia in addition to ED. PMID:26328208

  17. Multi-kinase inhibitors, AURKs and cancer.

    PubMed

    Cicenas, Jonas; Cicenas, Erikas

    2016-05-01

    Inhibitors that impact function of kinases are valuable both for the biological research as well as therapy of kinase-associated diseases, such as different cancers. There are quite a number of inhibitors, which are quite specific for certain kinases and several of them are either already approved for the cancer therapy or are in clinical studies of various phases. However, that does not mean that each single kinase inhibitor is suitable for targeted therapy. Some of them are not effective others might be toxic or fail some other criteria for the use in vivo. On the other hand, even in case of successful therapy, many responders eventually develop resistance to the inhibitors. The limitations of various single kinase inhibitors can be fought using compounds which target multiple kinases. This tactics can increase effectiveness of the inhibitors by the synergistic effect or help to diminish the likelihood of drug resistance. To date, several families of kinases are quite popular targets of the inhibition in cancers, such as tyrosine kinases, cycle-dependent kinases, mitogen-activated protein kinases, phosphoinositide 3-kinases as well as their pathway "players" and aurora kinases. Aurora kinases play an important role in the control of the mitosis and are often altered in diverse human cancers. Here, we will describe the most interesting multi-kinase inhibitors which inhibit aurora kinases among other targets and their use in preclinical and clinical cancer studies. PMID:27038473

  18. Interaction of Chloroplasts with Inhibitors

    PubMed Central

    Ridley, Stuart M.

    1983-01-01

    Several effects on pea (Pisum sativum L. var Onwards) chloroplasts of a new diphenylether herbicide, fomesafen (5-[2-chloro-4-trifluoromethyl-phenoxy]-N-methanesulfonyl-2 -nitrobenzamide) have been compared with those of a herbicide of related structure, nitrofluorfen (2-chloro-1-[4-nitrophenoxy]-4-[trifluoromethyl]benzene). Although both compounds produce the same light-dependent symptoms of desiccation and chlorosis indicative of a common primary mechanism of action, this study is concerned with a more broadly based investigation of different effects on the electron transport system. Comparisons have also been made with other compounds interacting with the chloroplast. Unlike nitrofluorfen, fomesafen has little effect as an inhibitor of electron flow or energy transfer. Both compounds have the ability to stimulate superoxide production through a functional electron transport system, and this involves specifically the p-nitro substituent. The stimulation, which is not likely to be an essential part of the primary herbicidal effect, is diminished under conditions that remove the coupling factor. Evidence suggests that both diphenylethers may be able to bind to the coupling factor, and kinetic studies reveal this for dibromothymoquinone as well. Such a binding site might be an important feature in allowing the primary effect of the diphenylether herbicides to be expressed. PMID:16663025

  19. Thrombin-activatable fibrinolysis inhibitor.

    PubMed

    Marx, Pauline F

    2004-09-01

    The coagulation system is a potent mechanism that prevents blood loss after vascular injury. It consists of a number of linked enzymatic reactions resulting in thrombin generation. Thrombin converts soluble fibrinogen into a fibrin clot. The clot is subsequently removed by the fibrinolytic system upon wound healing. Thrombin-activatable fibrinolysis inhibitor (TAFI), which is identical to the previously identified proteins procarboxypeptidase B, R, and U, forms a link between blood coagulation and fibrinolysis. TAFI circulates as an inactive proenzyme in the bloodstream, and becomes activated during blood clotting. The active form, TAFIa, inhibits fibrinolysis by cleaving off C-terminal lysine residues from partially degraded fibrin that stimulates the tissue-type plasminogen activator-mediated conversion of plasminogen to plasmin. Consequently, removal of these lysines leads to less plasmin formation and subsequently to protection of the fibrin clot from break down. Moreover, TAFI may also play a role in other processes such as, inflammation and tissue repair. In this review, recent developments in TAFI research are discussed. PMID:15379716

  20. Reverse transcriptase inhibitors as microbicides.

    PubMed

    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. PMID:22264043

  1. Increased inhibitor incidence in severe haemophilia A since 1990 attributable to more low titre inhibitors.

    PubMed

    van den Berg, H Marijke; Hashemi, S Mojtaba; Fischer, Kathelijn; Petrini, Pia; Ljung, Rolf; Rafowicz, Anne; Carcao, Manuel; Auerswald, Günter; Kurnik, Karin; Kenet, Gili; Santagostino, Elena

    2016-04-01

    Many studies have reported an increased incidence of inhibitors in previously untreated patients (PUPs) with severe haemophilia A after the introduction of recombinant products. It was the objective of this study to investigate whether the inhibitor incidence has increased between 1990 and 2009 in an unselected cohort of PUPs with severe haemophilia A (FVIII< 1 %). Patients were consecutively recruited from 31 haemophilia treatment centres in 16 countries and followed until 50 exposure days or until inhibitor development. Inhibitor development was studied in five-year birth cohorts comparing cumulative incidences. Furthermore the risk for inhibitor development per five-year birth cohort was studied using multivariable Cox regression, adjusting for potential genetic and treatment-related confounders. A total of 926 PUPs were included with a total cumulative inhibitor incidence of 27.5 %. The inhibitor incidence increased from 19.5 % in 1990-1994 (lowest) to 30.9 % in 2000-2004 (highest; p-value 0.011). Low titre inhibitor incidence increased from 3.1 % in 1990-1994 to 10.5 % in 2005-2009 (p-value 0.009). High titre inhibitor incidences remained stable over time. After 2000, risk of all inhibitor development was increased with adjusted hazard ratios 1.96 (95 % CI 1.06-2.83) in 2000-2004 and 2.34 (1.42-4.92) in 2005-2009. Screening for inhibitors was intensified over this 20-year study period from a median of 1.9 to 2.9 tests/year before 2000 to 2.7 to 4.3 tests/year after 2000. In conclusion, the cumulative inhibitor incidence has significantly increased between 1990 and 2009. The high titre inhibitor incidence has remained stable. PMID:26632988

  2. An Updated Review of Tyrosinase Inhibitors

    PubMed Central

    Chang, Te-Sheng

    2009-01-01

    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. PMID:19582213

  3. Migrating corrosion inhibitor protection of concrete

    SciTech Connect

    Bjegovic, D.; Miksic, B.

    1999-11-01

    Migrating corrosion inhibitors (MCI) were developed to protect steel rebar from corrosion in concrete. They were designed to be incorporated as an admixture during concrete batching or used for surface impregnation of existing concrete structures. Two investigations are summarized. One studied the effectiveness of MCIs as a corrosion inhibitor for steel rebar when used as an admixture in fresh concrete mix. The other is a long-term study of MCI concrete impregnation that chronicles corrosion rates of rebar in concrete specimens. Based on data from each study, it was concluded that migrating corrosion inhibitors are compatible with concrete and effectively delay the onset of corrosion.

  4. A tyrosinase inhibitor from Aspergillus niger.

    PubMed

    Vasantha, K Y; Murugesh, C S; Sattur, A P

    2014-10-01

    Tyrosinase, in the presence of oxygen, is the main culprit in post harvest browning of food products, resulting in the drop in its commercial value. In an effort to seek natural tyrosinase inhibitors for food applications, a screening programme was undertaken. Of the 26 fungal cultures isolated from soil samples of Agumbe forest, India, one isolate S16, identified as Aspergillus niger, gave an inhibition of 84 % against the enzyme. The inhibitor was isolated by following an enzyme inhibition assay guided purification protocol. The structure of the inhibitor was elucidated and found to be kojic acid. The IC50 of the Competitive inhibitor was found to be 8.8 μg with a Ki of 0.085 mM. PMID:25328242

  5. Structural Characterization of LRRK2 Inhibitors.

    PubMed

    Gilsbach, Bernd K; Messias, Ana C; Ito, Genta; Sattler, Michael; Alessi, Dario R; Wittinghofer, Alfred; Kortholt, Arjan

    2015-05-14

    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 structure-function analysis of such inhibitors, we mutated the active site of Dictyostelium Roco4 kinase to resemble LRRK2. Here, we show saturation transfer difference (STD) NMR and the first cocrystal structures of two potent in vitro inhibitors, LRRK2-IN-1 and compound 19, with mutated Roco4. Our data demonstrate that this system can serve as an excellent tool for the structural characterization and optimization of LRRK2 inhibitors using X-ray crystallography and NMR spectroscopy. PMID:25897865

  6. Transdermal delivery of Angiotensin Converting Enzyme inhibitors.

    PubMed

    Helal, Fouad; Lane, Majella E

    2014-09-01

    The Angiotensin Converting Enzyme (ACE) inhibitor class of drugs has been in clinical use since the 1970s for the management of all grades of heart failure, hypertension, diabetic nephropathy and prophylaxis of cardiovascular events. Because of the advantages associated with transdermal delivery compared with oral delivery many researchers have investigated the skin as a portal for administration of ACE inhibitors. This review summarises the various studies reported in the literature describing the development and evaluation of transdermal formulations of ACE inhibitors. Captopril, enalapril maleate, lisinopril dihydrate, perindopril erbumine and trandolapril are the most studied in connection with transdermal preparations. The methodologies reported are considered critically and the limitations of the various skin models used are also highlighted. Finally, opportunities for novel transdermal preparations of ACE inhibitor drugs are discussed with an emphasis on rational formulation design. PMID:24657822

  7. Inhibitors of alanine racemase enzyme: a review.

    PubMed

    Azam, Mohammed Afzal; Jayaram, Unni

    2016-08-01

    Alanine racemase is a fold type III PLP-dependent amino acid racemase enzyme catalysing the conversion of l-alanine to d-alanine utilised by bacterial cell wall for peptidoglycan synthesis. As there are no known homologs in humans, it is considered as an excellent antibacterial drug target. The standard inhibitors of this enzyme include O-carbamyl-d-serine, d-cycloserine, chlorovinyl glycine, alaphosphin, etc. d-Cycloserine is indicated for pulmonary and extra pulmonary tuberculosis but therapeutic use of drug is limited due to its severe toxic effects. Toxic effects due to off-target affinities of cycloserine and other substrate analogs have prompted new research efforts to identify alanine racemase inhibitors that are not substrate analogs. In this review, an updated status of known inhibitors of alanine racemase enzyme has been provided which will serve as a rich source of structural information and will be helpful in generating selective and potent inhibitor of alanine racemase. PMID:26024289

  8. Effects of multiphase flow on corrosion inhibitor

    SciTech Connect

    Chen, Y.; Jepson, W.P.; Chen, H.J.

    1999-11-01

    This paper investigates the inhibition performance of a typical imidazoline based inhibitor under multiphase flow. Electrochemical impedance spectroscopy (EIS) measurements were carried out in a 101.6 mm I.D., 15 m long acrylic flow loop using ASTM substitute saltwater and carbon dioxide gas. This flow loop system can generate slug flow, fill pipe flow and other multiphase flow patterns. Effects of different flow conditions on inhibition performance of this typical inhibitor were examined. The system was maintained at a pressure of 0.136 MPa and a temperature of 40 C. EIS measurements for this inhibitor in a Rotating Cylinder Electrode (RCE) system were also conducted. Different equivalent circuit models were used to fit the experiment data for both the RCE and flow loop systems. The high shear stress and turbulence due to the mixing vortex and the bubble impact in multiphase flow can enhance the corrosion or reduce the inhibition performance of inhibitors.

  9. Musical hallucinations treated with acetylcholinesterase inhibitors.

    PubMed

    Blom, Jan Dirk; Coebergh, Jan Adriaan F; Lauw, René; Sommer, Iris E C

    2015-01-01

    Musical hallucinations are relatively rare auditory percepts which, due to their intrusive nature and the accompanying fear of impending mental decline, tend to cause significant distress and impairment. Although their etiology and pathophysiology appear to be heterogeneous and no evidence-based treatment methods are available, case reports indicate that acetylcholinesterase inhibitors may yield positive results in patients with comorbid hearing loss. We present two female patients (aged 76 and 78 years) both of whom suffered from hearing impairment and practically incessant musical hallucinations. Both patients were successfully treated with the acetylcholinesterase inhibitor rivastigmine. Based on these two case descriptions and an overview of studies describing the use of acetylcholinesterase inhibitors in similar patients, we discuss possible mechanisms and propose further research on the use of acetylcholinesterase inhibitors for musical hallucinations experienced in concordance with hearing loss. PMID:25904872

  10. Musical Hallucinations Treated with Acetylcholinesterase Inhibitors

    PubMed Central

    Blom, Jan Dirk; Coebergh, Jan Adriaan F.; Lauw, René; Sommer, Iris E. C.

    2015-01-01

    Musical hallucinations are relatively rare auditory percepts which, due to their intrusive nature and the accompanying fear of impending mental decline, tend to cause significant distress and impairment. Although their etiology and pathophysiology appear to be heterogeneous and no evidence-based treatment methods are available, case reports indicate that acetylcholinesterase inhibitors may yield positive results in patients with comorbid hearing loss. We present two female patients (aged 76 and 78 years) both of whom suffered from hearing impairment and practically incessant musical hallucinations. Both patients were successfully treated with the acetylcholinesterase inhibitor rivastigmine. Based on these two case descriptions and an overview of studies describing the use of acetylcholinesterase inhibitors in similar patients, we discuss possible mechanisms and propose further research on the use of acetylcholinesterase inhibitors for musical hallucinations experienced in concordance with hearing loss. PMID:25904872

  11. Lipoxygenase inhibitors derived from marine macroalgae.

    PubMed

    Kurihara, Hideyuki; Kagawa, Yoshio; Konno, Remi; Kim, Sang Moo; Takahashi, Koretaro

    2014-03-01

    The solvent extracts from the algae Sargassum thunbergii (Sargassaceae) and Odonthalia corymbifera (Rhodomelaceae) were subjected to soybean lipoxygenase inhibitory screening. Two hydrophobic inhibitors were obtained from the extracts of S. thunbergii through inhibitory assay-guided fractionation. The inhibitors were identified as known exo-methylenic alkapolyenes (6Z,9Z,12Z,15Z)-1,6,9,12,15-henicosapentaene (1) and (6Z,9Z,12Z,15Z,18Z)-1,6,9,12,15,18-henicosahexaene (2). The alkapolyenes 1 and 2 showed higher inhibitory activity than the known inhibitor nordihydroguaiaretic acid (NDGA). Pheophytin a (3) was obtained from the extract of O. corymbifera. The inhibitor 3 also showed higher inhibitory activity than NDGA. This is the first report on lipoxygenase inhibition of exo-methylenic alkapolyenes and a chlorophyll a-related substance. PMID:24495846

  12. Inhibitors of acetylcholinesterase and butyrylcholinesterase meet immunity.

    PubMed

    Pohanka, Miroslav

    2014-01-01

    Acetylcholinesterase (AChE) inhibitors are widely used for the symptomatic treatment of Alzheimer's disease and other dementias. More recent use is for myasthenia gravis. Many of these inhibitors interact with the second known cholinesterase, butyrylcholinesterase (BChE). Further, evidence shows that acetylcholine plays a role in suppression of cytokine release through a "cholinergic anti-inflammatory pathway" which raises questions about the role of these inhibitors in the immune system. This review covers research and discussion of the role of the inhibitors in modulating the immune response using as examples the commonly available drugs, donepezil, galantamine, huperzine, neostigmine and pyridostigmine. Major attention is given to the cholinergic anti-inflammatory pathway, a well-described link between the central nervous system and terminal effector cells in the immune system. PMID:24893223

  13. Drug design from the cryptic inhibitor envelope

    PubMed Central

    Lee, Chul-Jin; Liang, Xiaofei; Wu, Qinglin; Najeeb, Javaria; Zhao, Jinshi; Gopalaswamy, Ramesh; Titecat, Marie; Sebbane, Florent; Lemaitre, Nadine; Toone, Eric J.; Zhou, Pei

    2016-01-01

    Conformational dynamics plays an important role in enzyme catalysis, allosteric regulation of protein functions and assembly of macromolecular complexes. Despite these well-established roles, such information has yet to be exploited for drug design. Here we show by nuclear magnetic resonance spectroscopy that inhibitors of LpxC—an essential enzyme of the lipid A biosynthetic pathway in Gram-negative bacteria and a validated novel antibiotic target—access alternative, minor population states in solution in addition to the ligand conformation observed in crystal structures. These conformations collectively delineate an inhibitor envelope that is invisible to crystallography, but is dynamically accessible by small molecules in solution. Drug design exploiting such a hidden inhibitor envelope has led to the development of potent antibiotics with inhibition constants in the single-digit picomolar range. The principle of the cryptic inhibitor envelope approach may be broadly applicable to other lead optimization campaigns to yield improved therapeutics. PMID:26912110

  14. Pharmacological caspase inhibitors: research towards therapeutic perspectives.

    PubMed

    Kudelova, J; Fleischmannova, J; Adamova, E; Matalova, E

    2015-08-01

    Caspases are key molecules of apoptosis and the inflammatory response. Up-regulation of the caspase cascade contributes to human pathologies such as neurodegenerative and immune disorders. Thus, blocking the excessive apoptosis by pharmacological inhibitors seems promising for therapeutic interventions in such diseases. Caspase inhibitors, both natural and artificial, have been used as research tools and have helped to define the role of the individual caspases in apoptosis and in non-apoptotic processes. Moreover, some caspase inhibitors have demonstrated their therapeutic efficiency in the reduction of cell death and inflammation in animal models of human diseases. However, no drug based on caspase inhibition has been approved on the market until now. Thus, the development of therapeutic approaches that specifically target caspases remains a great challenge and is now the focus of intense biological and clinical interest. Here, we provide a brief review of recent knowledge about pharmacological caspase inhibitors with special focus on their proposed clinical applications. PMID:26348072

  15. Biomass conversion inhibitors and in situ detoxification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inhibitory compounds derived from lignocellulosic biomass pretreatment are classified into aldehydes, ketones, organic acids, and phenols based on their chemical functional group that are toxic to fermentative microorganisms. Inhibitors and effects of inhibition to fermentative microbes vary depend...

  16. Small-Molecule Inhibitors of Urea Transporters

    PubMed Central

    Verkman, Alan S.; Esteva-Font, Cristina; Cil, Onur; Anderson, Marc O.; Li, Fei; Li, Min; Lei, Tianluo; Ren, Huiwen; Yang, Baoxue

    2015-01-01

    Urea transporter (UT) proteins, which include isoforms of UT-A in kidney tubule epithelia and UT-B in vasa recta endothelia and erythrocytes, facilitate urinary concentrating function. Inhibitors of urea transporter function have potential clinical applications as sodium-sparing diuretics, or ‘urearetics,’ in edema from different etiologies, such as congestive heart failure and cirrhosis, as well as in syndrome of inappropriate antidiuretic hormone (SIADH). High-throughput screening of drug-like small molecules has identified UT-A and UT-B inhibitors with nanomolar potency. Inhibitors have been identified with different UT-A versus UT-B selectivity profiles and putative binding sites on UT proteins. Studies in rodent models support the utility of UT inhibitors in reducing urinary concentration, though testing in clinically relevant animal models of edema has not yet been done. PMID:25298345

  17. Progress and prospects on DENV protease inhibitors.

    PubMed

    Timiri, Ajay Kumar; Sinha, Barij Nayan; Jayaprakash, Venkatesan

    2016-07-19

    New treatments are desperately required to combat increasing rate of dengue fever cases reported in tropical and sub-tropical parts of the world. Among the ten proteins (structural and non-structural) encoded by dengue viral genome, NS2B-NS3 protease is an ideal target for drug discovery. It is responsible for the processing of poly protein that is required for genome replication of the virus. Moreover, inhibitors designed against proteases were found successful in Human Immuno-deficiency Virus (HIV) and Hepatitis C Virus (HCV). Complete molecular mechanism and a survey of inhibitors reported against dengue protease will be helpful in designing effective and potent inhibitors. This review provides an insight on molecular mechanism of dengue virus protease and covers up-to-date information on different inhibitors reported against dengue proteases with medicinal chemistry perspective. PMID:27092412

  18. Inhibitors of Acetylcholinesterase and Butyrylcholinesterase Meet Immunity

    PubMed Central

    Pohanka, Miroslav

    2014-01-01

    Acetylcholinesterase (AChE) inhibitors are widely used for the symptomatic treatment of Alzheimer’s disease and other dementias. More recent use is for myasthenia gravis. Many of these inhibitors interact with the second known cholinesterase, butyrylcholinesterase (BChE). Further, evidence shows that acetylcholine plays a role in suppression of cytokine release through a “cholinergic anti-inflammatory pathway” which raises questions about the role of these inhibitors in the immune system. This review covers research and discussion of the role of the inhibitors in modulating the immune response using as examples the commonly available drugs, donepezil, galantamine, huperzine, neostigmine and pyridostigmine. Major attention is given to the cholinergic anti-inflammatory pathway, a well-described link between the central nervous system and terminal effector cells in the immune system. PMID:24893223

  19. Temperature effects on inhibitors and corrosion inhibition

    SciTech Connect

    Raman, A.

    1996-12-01

    Inhibitor systems commonly employed in industrial operations at elevated and high temperatures are surveyed and the available literature data on their performance characteristics at elevated temperatures are analyzed. The functional behavior of phosphates, amines, benzotriazole, and other important inhibitors are briefly summarized. The inhibitors degrade due to thermal decomposition and/or reaction on the metal surface or with other species present in the environment. Degradation modes of various kinds of amines used in steam systems are reviewed and the resultant limitations for use pointed out. Inhibitor systems in heating, heat exchanger-type cooling, hot acid pickling, in hot corrosive environments in turbine engines, as well as systems to prevent stress corrosion cracking at elevated temperatures are analyzed based on literature data.

  20. Selective Phosphodiesterase 4B Inhibitors: A Review

    PubMed Central

    Azam, Mohammed Afzal; Tripuraneni, Naga Srinivas

    2014-01-01

    Abstract Phosphodiesterase 4B (PDE4B) is a member of the phosphodiesterase family of proteins that plays a critical role in regulating intracellular levels of cyclic adenosine monophosphate (cAMP) by controlling its rate of degradation. It has been demonstrated that this isoform is involved in the orchestra of events which includes inflammation, schizophrenia, cancers, chronic obstructive pulmonary disease, contractility of the myocardium, and psoriatic arthritis. Phosphodiesterase 4B has constituted an interesting target for drug development. In recent years, a number of PDE4B inhibitors have been developed for their use as therapeutic agents. In this review, an up-to-date status of the inhibitors investigated for the inhibition of PDE4B has been given so that this rich source of structural information of presently known PDE4B inhibitors could be helpful in generating a selective and potent inhibitor of PDE4B. PMID:25853062

  1. Ocular Toxicity of Tyrosine Kinase Inhibitors

    PubMed Central

    Davis, Mary Elizabeth

    2016-01-01

    Purpose/Objectives To review common tyrosine kinase inhibitors, as well as their ocular side effects and management. Data Sources A comprehensive literature search was conducted using cINahl®, Pubmed, and cochrane databases for articles published since 2004 with the following search terms: ocular toxicities, tyrosine kinase inhibitors, ophthalmology, adverse events, eye, and vision. Data Synthesis Tyrosine kinase inhibitors can cause significant eye toxicity. Conclusions Given the prevalence of new tyrosine kinase inhibitor therapies and the complexity of possible pathogenesis of ocular pathology, oncology nurses can appreciate the occurrence of ocular toxicities and the role of nursing in the management of these problems. Implications for Nursing Knowledge of the risk factors and etiology of ocular toxicity of targeted cancer therapies can guide nursing assessment, enhance patient education, and improve care management. Including a review of eye symptoms and vision issues in nursing assessment can enhance early detection and treatment of ocular toxicity. PMID:26906134

  2. Proteasome inhibitor associated thrombotic microangiopathy.

    PubMed

    Yui, Jennifer C; Van Keer, Jan; Weiss, Brendan M; Waxman, Adam J; Palmer, Matthew B; D'Agati, Vivette D; Kastritis, Efstathios; Dimopoulos, Meletios A; Vij, Ravi; Bansal, Dhruv; Dingli, David; Nasr, Samih H; Leung, Nelson

    2016-09-01

    A variety of medications have been implicated in the causation of thrombotic microangiopathy (TMA). Recently, a few case reports have emerged of TMA attributed to the proteasome inhibitors (PI) bortezomib and carfilzomib in patients with multiple myeloma. The aim of this case series was to better characterize the role of PI in the etiology of drug-induced TMA. We describe eleven patients from six medical centers from around the world who developed TMA while being treated with PI. The median time between medication initiation and diagnosis of TMA was 21 days (range 5 days to 17 months). Median laboratory values at diagnosis included hemoglobin-7.5 g dL(-1) , platelet count-20 × 10(9) /L, LDH-698 U L(-1) , creatinine-3.12 mg dL(-1) . No patient had any other cause of TMA, including ADAMTS13 inhibition, other malignancy or use of any other medication previously associated with TMA. Nine patients had resolution of TMA without evidence of hemolysis after withdrawal of PI. Two patients had stabilization of laboratory values but persistent evidence of hemolysis despite medication withdrawal. One patient had recurrence of TMA with rechallenge of PI. There is a strong level of evidence that PI can cause DITMA. In evaluating patients with suspected TMA, PI use should be recognized as a potential etiology, and these medications should be discontinued promptly if thought to be the cause of TMA. Am. J. Hematol. 91:E348-E352, 2016. © 2016 Wiley Periodicals, Inc. PMID:27286661

  3. Proton pump inhibitors and pain.

    PubMed

    Smith, Howard S; Dhingra, Reena; Ryckewaert, Lori; Bonner, Dave

    2009-01-01

    There may be a relationship between proton pump inhibitors (PPIs) and iron absorption. PPIs may decrease the amount of iron absorbed gastrointestinally specifically due to alteration of the pH in the duodenum. Restless legs syndrome (RLS) is a sensorimotor disorder that includes an urge to move legs, accompanied or caused by uncomfortable and unpleasant sensations in the legs; the urge to move begins or worsens during periods of rest or inactivity, the urge to move is partially or totally relieved by movement, and the urge is worse or only occurs at night. In the majority of the restless leg syndrome population, the sensation is deep seated, often described as being in the shin bones, and most commonly felt between the knee and ankle. It may be described as a creepy, shock-like, tense, electric, buzzing, itchy, or even numb sensation. A subpopulation of this restless leg syndrome patient population experiences restless leg syndrome associated pain (RLSAP) that has been described as a deep "achy pain." This pain has not been found to be relieved by many of the typical over the counter analgesics. Often, constant movement of the legs appears to be the only remedy, as these sensations usually appear during periods of rest. Furthermore, there appears to be an association between iron deficiency and those suffering from Restless Leg Syndrome (RLS). The authors theorize that there may be a possible correlation between PPIs and the symptoms (e.g. pain) associated with RLS. The authors propose that PPIs, such as omeprazole, may interfere with iron absorption in certain patients and that a subpopulation of patients who develop significant iron deficiency characterized by low serum ferritin levels while on PPIs may also develop RLS-like symptoms (including RLSAP). While there is no robust direct evidence to support any associations of PPIs and iron deficiency or PPIs associated with RLS-like symptoms (including RLSAP), it is hoped that this manuscript may spark research

  4. 2,4-Diaminopyrimidine MK2 inhibitors. Part I: Observation of an unexpected inhibitor binding mode

    SciTech Connect

    Argiriadi, Maria A.; Ericsson, Anna M.; Harris, Christopher M.; Banach, David L.; Borhani, David W.; Calderwood, David J.; Demers, Megan D.; DiMauro, Jennifer; Dixon, Richard W.; Hardman, Jennifer; Kwak, Silvia; Li, Biqin; Mankovich, John A.; Marcotte, Douglas; Mullen, Kelly D.; Ni, Baofu; Pietras, M.; Sadhukhan, Ramkrishna; Sousa, Silvino; Tomlinson, Medha J.; Wang, L.; Xiang, T.; Talanian, R.V.

    2010-09-17

    MK2 is a Ser/Thr kinase of significant interest as an anti-inflammatory drug discovery target. Here we describe the development of in vitro tools for the identification and characterization of MK2 inhibitors, including validation of inhibitor interactions with the crystallography construct and determination of the unique binding mode of 2,4-diaminopyrimidine inhibitors in the MK2 active site.

  5. HIV pharmacotherapy: A review of integrase inhibitors.

    PubMed

    Wong, Elaine; Trustman, Nathan; Yalong, April

    2016-02-01

    Integrase strand transfer inhibitors (INSTIs) are a class of antiretroviral agents used to treat HIV. These drugs--raltegravir, elvitegravir, and dolutegravir--are preferred options for treatment-naïve patients when used in combination with two nucleoside reverse transcriptase inhibitors. Based on clinical trials, INSTIs have been proven to be effective with minimal safety concerns. This article reviews the pharmacologic profile, role in therapy, and safety and efficacy of each agent. PMID:26818644

  6. Influenza virus neuraminidase: structure, antibodies, and inhibitors.

    PubMed Central

    Colman, P. M.

    1994-01-01

    The determination of the 3-dimensional structure of the influenza virus neuraminidase in 1983 has served as a platform for understanding interactions between antibodies and protein antigens, for investigating antigenic variation in influenza viruses, and for devising new inhibitors of the enzyme. That work is reviewed here, together with more recent developments that have resulted in one of the inhibitors entering clinical trials as an anti-influenza virus drug. PMID:7849585

  7. Heterocyclics as corrosion inhibitors for acid media

    SciTech Connect

    Ajmal, M.; Khan, M.A.W.; Ahmad, S.; Quraishi, M.A.

    1996-12-01

    The available literature on the use of heterocyclic compounds as corrosion inhibitors in acid media has been reviewed. It has been noted that the workers in this field have either used sulfur or nitrogen containing heterocyclic compounds for studying inhibition action. The authors have synthesized compounds containing sulfur and nitrogen both in the same ring and studied their inhibition action in acid media. These compounds were found to be better inhibitors than those containing either atoms alone.

  8. On the selectivity of neuronal NOS inhibitors

    PubMed Central

    Pigott, B; Bartus, K; Garthwaite, J

    2013-01-01

    Background and Purpose Isoform-selective inhibitors of NOS enzymes are desirable as research tools and for potential therapeutic purposes. Vinyl-l-N-5-(1-imino-3-butenyl)-l-ornithine (l-VNIO) and Nω-propyl-l-arginine (NPA) purportedly have good selectivity for neuronal over endothelial NOS under cell-free conditions, as does N-[(3-aminomethyl)benzyl]acetamidine (1400W), which is primarily an inducible NOS inhibitor. Although used in numerous investigations in vitro and in vivo, there have been surprisingly few tests of the potency and selectivity of these compounds in cells. This study addresses this deficiency and evaluates the activity of new and potentially better pyrrolidine-based compounds. Experimental Approach The inhibitors were evaluated by measuring their effect on NMDA-evoked cGMP accumulation in rodent hippocampal slices, a response dependent on neuronal NOS, and ACh-evoked cGMP synthesis in aortic rings of the same animals, an endothelial NOS-dependent phenomenon. Key Results l-VNIO, NPA and 1400W inhibited responses in both tissues but all showed less than fivefold higher potency in the hippocampus than in the aorta, implying useless selectivity for neuronal over endothelial NOS at the tissue level. In addition, the inhibitors had a 25-fold lower potency in the hippocampus than reported previously, the IC50 values being approximately 1 μM for l-VNIO and NPA, and 150 μM for 1400W. Pyrrolidine-based inhibitors were similarly weak and nonselective. Conclusion and Implications The results suggest that l-VNIO, NPA and 1400W, as well as the newer pyrrolidine-type inhibitors, cannot be used as neuronal NOS inhibitors in cells without stringent verification. The identification of inhibitors with useable selectivity in cells and tissues remains an important goal. PMID:23072468

  9. Endogenous angiogenesis inhibitors and their therapeutic implications.

    PubMed

    Cao, Y

    2001-04-01

    A number of endogenous inhibitors targeting the tumor vasculature have recently been identified using in vitro and in vivo antiangiogenesis models. While many of these angiogenesis inhibitors display a broad spectrum of biological actions on several systems in the body, several inhibitors including angiostatin, endostatin, and serpin antithrombin seem to act specifically on the proliferating endothelial cell compartment of the newly formed blood vessels. The discovery of these specific endothelial inhibitors not only increases our understanding of the functions of these molecules in the regulation of physiological and pathological angiogenesis, but may also provide an important therapeutic strategy for the treatment of cancer and other angiogenesis dependent diseases, including diabetic retinopathy and chronic inflammations. Systemic administration of these angiogenesis inhibitors in animals significantly suppresses the growth of a variety of tumors and their metastases. However, their production as functional recombinant proteins has been proven to be difficult. In addition, high dosages of these inhibitors are required to suppress tumor growth in animal studies. Other disadvantages of the antiangiogenic protein therapy include repeated injections, prolonged treatment, transmission of toxins and infectious particles, and high cost for manufacturing large amounts of protein molecules. Thus, alternative strategies need to be developed in order to improve the clinical settings of antiangiogenic therapy. Developments of these strategies are ongoing and they include identification of more potent inhibitors, antiangiogenic gene therapy, improvement of protein/compound half-lives in the circulation, increase of their concentrations at the disease location, and combinatorial therapies with approaches including chemotherapy, radiotherapy, and immunotherapy. Despite the above-mentioned disadvantages, a few inhibitors have entered into the early stages of clinical trials and

  10. Update on TNF Inhibitors in Dermatology.

    PubMed

    Sobell, Jeffrey M

    2016-06-01

    Emerging data describe new potential indications for tumor necrosis factor (TNF) inhibitors in dermatology, including pediatric psoriasis and hidradenitis suppurativa. New biosimilar TNF agents are in late stages of development and may be available in the United States in the near future. Biosimilar agents are similar but not identical to available TNF inhibitors, and approval requires extensive analytic, toxicity, pharmacokinetic, pharmacodynamic, and clinical testing. Semin Cutan Med Surg 35(supp6):S104-S106. PMID:27537073

  11. Aromatase inhibitors in the treatment of endometriosis.

    PubMed

    Słopień, Radosław; Męczekalski, Błażej

    2016-03-01

    Endometriosis is a chronic inflammatory condition in which foci of endometrial tissue grow outside of the uterine cavity. Endometriosis was estimated to affect 176 million women of childbearing potential all over the world in 2010. The presence of extrauterine endometrial tissue is associated with pain and infertility. Typical symptoms of endometriosis include dysmenorrhoea, dyspareunia, heavy menstrual periods (menorrhagia), pelvic pain that is not related to menstrual cycles, dysuria, and chronic fatigue. Medical treatments for endometriosis include combined oral contraceptive pills, danazol, gestrinone, medroxyprogesterone acetate, and gonadotropin-releasing hormone agonists (aGnRHs). A new class of medications called aromatase inhibitors has been identified in recent years as potential therapeutic agents for endometriosis. This article provides general information about aromatase inhibitors, their use in gynaecology, and their adverse effects. In particular, the paper discusses the use of aromatase inhibitors in the treatment of endometriosis in postmenopausal women. Unlike oral contraceptives, gestagens, aGnRHs, and danazol, which suppress ovarian oestrogen synthesis, aromatase inhibitors inhibit mainly extra-ovarian synthesis of oestrogens. Therefore, the use of aromatase inhibitors seems to be particularly relevant in older patients, as most of the body's oestrogen is produced outside the ovaries after menopause. The paper discusses also the use of aromatase inhibitors in the treatment of pain associated with endometriosis and infertility caused by endometriosis. PMID:27095958

  12. FERRITIN H INDUCTION BY HISTONE DEACETYLASE INHIBITORS

    PubMed Central

    Wang, Wei; Di, Xiumin; Torti, Suzy V.; Torti, Frank M.

    2010-01-01

    Because both iron deficiency and iron excess are deleterious to normal cell function, the intracellular level of iron must be tightly controlled. Ferritin, an iron binding protein, regulates iron balance by storing iron in a bioavailable but non-toxic form. Ferritin protein comprises two subunits: ferritin H, which contains ferroxidase activity, and ferritin L. Here we demonstrate that ferritin H mRNA and protein are induced by histone deacetylase inhibitors (HDAC inhibitors), a promising class of anti-cancer drugs, in cultured human cancer cells. Deletion analysis and EMSA assays reveal that the induction of ferritin H occurs at a transcriptional level via Sp1 and NF-Y binding sites near the transcriptional start site of the human ferritin H promoter. Classically, HDAC inhibitors modulate gene expression by increasing histone acetylation. However, ChIP assays demonstrate that HDAC inhibitors induce ferritin H transcription by increasing NF-Y binding to the ferritin H promoter without changes in histone acetylation. These results identify ferritin H as a new target of HDAC inhibitors, and recruitment of NF-Y as a novel mechanism of action of HDAC inhibitors. PMID:20385107

  13. Discovery of Novel Haloalkane Dehalogenase Inhibitors

    PubMed Central

    Buryska, Tomas; Daniel, Lukas; Kunka, Antonin; Brezovsky, Jan; Damborsky, Jiri

    2016-01-01

    Haloalkane dehalogenases (HLDs) have recently been discovered in a number of bacteria, including symbionts and pathogens of both plants and humans. However, the biological roles of HLDs in these organisms are unclear. The development of efficient HLD inhibitors serving as molecular probes to explore their function would represent an important step toward a better understanding of these interesting enzymes. Here we report the identification of inhibitors for this enzyme family using two different approaches. The first builds on the structures of the enzymes' known substrates and led to the discovery of less potent nonspecific HLD inhibitors. The second approach involved the virtual screening of 150,000 potential inhibitors against the crystal structure of an HLD from the human pathogen Mycobacterium tuberculosis H37Rv. The best inhibitor exhibited high specificity for the target structure, with an inhibition constant of 3 μM and a molecular architecture that clearly differs from those of all known HLD substrates. The new inhibitors will be used to study the natural functions of HLDs in bacteria, to probe their mechanisms, and to achieve their stabilization. PMID:26773086

  14. PARP1 Inhibitors: antitumor drug design

    PubMed Central

    Malyuchenko, N. V.; Kotova, E. Yu.; Kulaeva, O. I.; Kirpichnikov, M. P.; Studitskiy, V. M.

    2015-01-01

    The poly (ADP-ribose) polymerase 1 (PARP1) enzyme is one of the promising molecular targets for the discovery of antitumor drugs. PARP1 is a common nuclear protein (1–2 million molecules per cell) serving as a “sensor” for DNA strand breaks. Increased PARP1 expression is sometimes observed in melanomas, breast cancer, lung cancer, and other neoplastic diseases. The PARP1 expression level is a prognostic indicator and is associated with a poor survival prognosis. There is evidence that high PARP1 expression and treatment-resistance of tumors are correlated. PARP1 inhibitors are promising antitumor agents, since they act as chemo- and radiosensitizers in the conventional therapy of malignant tumors. Furthermore, PARP1 inhibitors can be used as independent, effective drugs against tumors with broken DNA repair mechanisms. Currently, third-generation PARP1 inhibitors are being developed, many of which are undergoing Phase II clinical trials. In this review, we focus on the properties and features of the PARP1 inhibitors identified in preclinical and clinical trials. We also describe some problems associated with the application of PARP1 inhibitors. The possibility of developing new PARP1 inhibitors aimed at DNA binding and transcriptional activity rather than the catalytic domain of the protein is discussed. PMID:26483957

  15. Discovery of Novel Haloalkane Dehalogenase Inhibitors.

    PubMed

    Buryska, Tomas; Daniel, Lukas; Kunka, Antonin; Brezovsky, Jan; Damborsky, Jiri; Prokop, Zbynek

    2016-03-01

    Haloalkane dehalogenases (HLDs) have recently been discovered in a number of bacteria, including symbionts and pathogens of both plants and humans. However, the biological roles of HLDs in these organisms are unclear. The development of efficient HLD inhibitors serving as molecular probes to explore their function would represent an important step toward a better understanding of these interesting enzymes. Here we report the identification of inhibitors for this enzyme family using two different approaches. The first builds on the structures of the enzymes' known substrates and led to the discovery of less potent nonspecific HLD inhibitors. The second approach involved the virtual screening of 150,000 potential inhibitors against the crystal structure of an HLD from the human pathogen Mycobacterium tuberculosis H37Rv. The best inhibitor exhibited high specificity for the target structure, with an inhibition constant of 3 μM and a molecular architecture that clearly differs from those of all known HLD substrates. The new inhibitors will be used to study the natural functions of HLDs in bacteria, to probe their mechanisms, and to achieve their stabilization. PMID:26773086

  16. Aromatase inhibitors in the treatment of endometriosis

    PubMed Central

    Męczekalski, Błażej

    2016-01-01

    Endometriosis is a chronic inflammatory condition in which foci of endometrial tissue grow outside of the uterine cavity. Endometriosis was estimated to affect 176 million women of childbearing potential all over the world in 2010. The presence of extrauterine endometrial tissue is associated with pain and infertility. Typical symptoms of endometriosis include dysmenorrhoea, dyspareunia, heavy menstrual periods (menorrhagia), pelvic pain that is not related to menstrual cycles, dysuria, and chronic fatigue. Medical treatments for endometriosis include combined oral contraceptive pills, danazol, gestrinone, medroxyprogesterone acetate, and gonadotropin-releasing hormone agonists (aGnRHs). A new class of medications called aromatase inhibitors has been identified in recent years as potential therapeutic agents for endometriosis. This article provides general information about aromatase inhibitors, their use in gynaecology, and their adverse effects. In particular, the paper discusses the use of aromatase inhibitors in the treatment of endometriosis in postmenopausal women. Unlike oral contraceptives, gestagens, aGnRHs, and danazol, which suppress ovarian oestrogen synthesis, aromatase inhibitors inhibit mainly extra-ovarian synthesis of oestrogens. Therefore, the use of aromatase inhibitors seems to be particularly relevant in older patients, as most of the body's oestrogen is produced outside the ovaries after menopause. The paper discusses also the use of aromatase inhibitors in the treatment of pain associated with endometriosis and infertility caused by endometriosis. PMID:27095958

  17. Potent pyrrolidine- and piperidine-based BACE-1 inhibitors

    SciTech Connect

    Iserloh, U.; Wu, Y.; Cumming, J.N.; Pan, J.; Wang, L.Y.; Stamford, A.W.; Kennedy, M.E.; Kuvelkar, R.; Chen, X.; Parker, E.M.; Strickland, C.; Voigt, J.

    2008-08-18

    Based on lead compound 1 identified from the patent literature, we developed novel patentable BACE-1 inhibitors by introducing a cyclic amine scaffold. Extensive SAR studies on both pyrrolidines and piperidines ultimately led to inhibitor 2f, one of the most potent inhibitors synthesized to date. The discovery and development of novel BACE-1 inhibitors incorporating a cyclic amine scaffold is described.

  18. Corrosion inhibitors for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1978-01-01

    Inhibitors which appeared promising in previous tests and additional inhibitors including several proprietary products were evaluated. Evaluation of the inhibitors was based on corrosion protection afforded an aluminum-mild steel-copper-stainless steel assembly in a hot corrosive water. Of the inhibitors tested two were found to be effective and show promise for protecting multimetallic solar heating systems.

  19. Selective serotonin reuptake inhibitor exposure.

    PubMed

    Fitzgerald, Kevin T; Bronstein, Alvin C

    2013-02-01

    Many antidepressants inhibit serotonin or norepinephrine reuptake or both to achieve their clinical effect. The selective serotonin reuptake inhibitor class of antidepressants (SSRIs) includes citalopram, escitalopram (active enantiomer of citalopram), fluoxetine, fluvoxamine, paroxetine, and sertraline. The SSRIs are as effective as tricyclic antidepressants in treatment of major depression with less significant side effects. As a result, they have become the largest class of medications prescribed to humans for depression. They are also used to treat obsessive-compulsive disorder, panic disorders, alcoholism, obesity, migraines, and chronic pain. An SSRI (fluoxetine) has been approved for veterinary use in treatment of canine separation anxiety. SSRIs act specifically on synaptic serotonin concentrations by blocking its reuptake in the presynapse and increasing levels in the presynaptic membrane. Clinical signs of SSRI overdose result from excessive amounts of serotonin in the central nervous system. These signs include nausea, vomiting, mydriasis, hypersalivation, and hyperthermia. Clinical signs are dose dependent and higher dosages may result in the serotonin syndrome that manifests itself as ataxia, tremors, muscle rigidity, hyperthermia, diarrhea, and seizures. Current studies reveal no increase in appearance of any specific clinical signs of serotonin toxicity with regard to any SSRI medication. In people, citalopram has been reported to have an increased risk of electrocardiographic abnormalities. Diagnosis of SSRI poisoning is based on history, clinical signs, and response to therapy. No single clinical test is currently available to confirm SSRI toxicosis. The goals of treatment in this intoxication are to support the animal, prevent further absorption of the drug, support the central nervous system, control hyperthermia, and halt any seizure activity. The relative safety of the SSRIs in overdose despite the occurrence of serotonin syndrome makes them

  20. Combined effects of EGFR tyrosine kinase inhibitors and vATPase inhibitors in NSCLC cells

    SciTech Connect

    Jin, Hyeon-Ok; Hong, Sung-Eun; Kim, Chang Soon; Park, Jin-Ah; Kim, Jin-Hee; Kim, Ji-Young; Kim, Bora; Chang, Yoon Hwan; Hong, Seok-Il; Hong, Young Jun; Park, In-Chul; Lee, Jin Kyung

    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.

  1. SGLT2 Inhibitors and the Diabetic Kidney.

    PubMed

    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

  2. Three Decades of β-Lactamase Inhibitors

    PubMed Central

    Drawz, Sarah M.; Bonomo, Robert A.

    2010-01-01

    Summary: Since the introduction of penicillin, β-lactam antibiotics have been the antimicrobial agents of choice. Unfortunately, the efficacy of these life-saving antibiotics is significantly threatened by bacterial β-lactamases. β-Lactamases are now responsible for resistance to penicillins, extended-spectrum cephalosporins, monobactams, and carbapenems. In order to overcome β-lactamase-mediated resistance, β-lactamase inhibitors (clavulanate, sulbactam, and tazobactam) were introduced into clinical practice. These inhibitors greatly enhance the efficacy of their partner β-lactams (amoxicillin, ampicillin, piperacillin, and ticarcillin) in the treatment of serious Enterobacteriaceae and penicillin-resistant staphylococcal infections. However, selective pressure from excess antibiotic use accelerated the emergence of resistance to β-lactam-β-lactamase inhibitor combinations. Furthermore, the prevalence of clinically relevant β-lactamases from other classes that are resistant to inhibition is rapidly increasing. There is an urgent need for effective inhibitors that can restore the activity of β-lactams. Here, we review the catalytic mechanisms of each β-lactamase class. We then discuss approaches for circumventing β-lactamase-mediated resistance, including properties and characteristics of mechanism-based inactivators. We next highlight the mechanisms of action and salient clinical and microbiological features of β-lactamase inhibitors. We also emphasize their therapeutic applications. We close by focusing on novel compounds and the chemical features of these agents that may contribute to a “second generation” of inhibitors. The goal for the next 3 decades will be to design inhibitors that will be effective for more than a single class of β-lactamases. PMID:20065329

  3. Polyphenol oxidase inhibitor(s) from German cockroach (Blattella germanica) extract

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An extract from German cockroach appears effective in inhibiting browning on apples and potatoes. Successful identification of inhibitor(s) of PPO from German cockroach would be useful to the fruit and vegetable segments of the food industry, due to the losses they incur from enzymatic browning. Ide...

  4. Inhibitors Selective for Mycobacterial Versus Human Proteasomes

    SciTech Connect

    Lin, G.; Li, D; Sorio de Carvalho, L; Deng, H; Tao, H; Vogt, G; Wu, K; Schneider, J; Chidawanyika, T; et. al.

    2009-01-01

    Many anti-infectives inhibit the synthesis of bacterial proteins, but none selectively inhibits their degradation. Most anti-infectives kill replicating pathogens, but few preferentially kill pathogens that have been forced into a non-replicating state by conditions in the host. To explore these alternative approaches we sought selective inhibitors of the proteasome of Mycobacterium tuberculosis. Given that the proteasome structure is extensively conserved, it is not surprising that inhibitors of all chemical classes tested have blocked both eukaryotic and prokaryotic proteasomes, and no inhibitor has proved substantially more potent on proteasomes of pathogens than of their hosts. Here we show that certain oxathiazol-2-one compounds kill non-replicating M.?tuberculosis and act as selective suicide-substrate inhibitors of the M.?tuberculosis proteasome by cyclocarbonylating its active site threonine. Major conformational changes protect the inhibitor-enzyme intermediate from hydrolysis, allowing formation of an oxazolidin-2-one and preventing regeneration of active protease. Residues outside the active site whose hydrogen bonds stabilize the critical loop before and after it moves are extensively non-conserved. This may account for the ability of oxathiazol-2-one compounds to inhibit the mycobacterial proteasome potently and irreversibly while largely sparing the human homologue.

  5. Inhibitors in LPE growth of garnets

    NASA Astrophysics Data System (ADS)

    De Roode, W. H.; Robertson, J. M.

    1983-09-01

    The growth rate of LPE growth garnets can be reduced considerably by the addition of small amounts of group II oxides. This effect can be helpful for the controlled growth of very thin garnet films for sub-micron bubbles and optical devices. The largest effect was found with the addition of Mg 2+ and Ca 2+, resulting in a maximum decrease of the growth rate of approximately 70%. A semi-empirical formula was used to describe the growth rate as a function of the dipping temperature. The change in the growth rate on the addition of the inhibitor ion at constant temperature was found to be proportional to ( aMO)/( aMO+2 Ln 2O 3), where M is a group II element, Ln 2O 2 is the sum of the yttrium and RE oxides in the melt, and a is the inhibitor factor. The value of the inhibitor factor depends on both the inhibitor ion as well as the composition of the garnet. The lowering of the growth rate on the addition of an inhibitor ion is explained by the introduction of an extra growth resistance due to the charge compensation mechanism of the divalent ions. The influence of the different charge compensation possibilities in the garnet system is examined and the relative importance of these possibilities for charge compensation is discussed.

  6. Clinical Development of Immune Checkpoint Inhibitors.

    PubMed

    Ito, Ayumu; Kondo, Shunsuke; Tada, Kohei; Kitano, Shigehisa

    2015-01-01

    Recent progress in cancer immunotherapy has been remarkable. Most striking are the clinical development and approval of immunomodulators, also known as immune checkpoint inhibitors. These monoclonal antibodies (mAb) are directed to immune checkpoint molecules, which are expressed on immune cells and mediate signals to attenuate excessive immune reactions. Although mAbs targeting tumor associated antigens, such as anti-CD20 mAb and anti-Her2 mAb, directly recognize tumor cells and induce cell death, immune checkpoint inhibitors restore and augment the antitumor immune activities of cytotoxic T cells by blocking immune checkpoint molecules on T cells or their ligands on antigen presenting and tumor cells. Based on preclinical data, many clinical trials have demonstrated the acceptable safety profiles and efficacies of immune checkpoint inhibitors in a variety of cancers. The first in class approved immune checkpoint inhibitor is ipilimumab, an anti-CTLA-4 (cytotoxic T lymphocyte antigen-4) mAb. Two pivotal phase III randomized controlled trials demonstrated a survival benefit in patients with metastatic melanoma. In 2011, the US Food and Drug Administration (FDA) approved ipilimumab for metastatic melanoma. Several clinical trials have since investigated new agents, alone and in combination, for various cancers. In this review, we discuss the current development status of and future challenges in utilizing immune checkpoint inhibitors. PMID:26161407

  7. Clinical Development of Immune Checkpoint Inhibitors

    PubMed Central

    Ito, Ayumu; Kondo, Shunsuke; Tada, Kohei; Kitano, Shigehisa

    2015-01-01

    Recent progress in cancer immunotherapy has been remarkable. Most striking are the clinical development and approval of immunomodulators, also known as immune checkpoint inhibitors. These monoclonal antibodies (mAb) are directed to immune checkpoint molecules, which are expressed on immune cells and mediate signals to attenuate excessive immune reactions. Although mAbs targeting tumor associated antigens, such as anti-CD20 mAb and anti-Her2 mAb, directly recognize tumor cells and induce cell death, immune checkpoint inhibitors restore and augment the antitumor immune activities of cytotoxic T cells by blocking immune checkpoint molecules on T cells or their ligands on antigen presenting and tumor cells. Based on preclinical data, many clinical trials have demonstrated the acceptable safety profiles and efficacies of immune checkpoint inhibitors in a variety of cancers. The first in class approved immune checkpoint inhibitor is ipilimumab, an anti-CTLA-4 (cytotoxic T lymphocyte antigen-4) mAb. Two pivotal phase III randomized controlled trials demonstrated a survival benefit in patients with metastatic melanoma. In 2011, the US Food and Drug Administration (FDA) approved ipilimumab for metastatic melanoma. Several clinical trials have since investigated new agents, alone and in combination, for various cancers. In this review, we discuss the current development status of and future challenges in utilizing immune checkpoint inhibitors. PMID:26161407

  8. Inhibitors of the Metalloproteinase Anthrax Lethal Factor.

    PubMed

    Goldberg, Allison B; Turk, Benjamin E

    2016-01-01

    Bacillus anthracis, a rod shaped, spore forming, gram positive bacteria, is the etiological agent of anthrax. B. anthracis virulence is partly attributable to two secreted bipartite protein toxins, which act inside host cells to disrupt signaling pathways important for host defense against infection. These toxins may also directly contribute to mortality in late stage infection. The zinc-dependent metalloproteinase anthrax lethal factor (LF) is a critical component of one of these protein toxins and a prime target for inhibitor development to produce anthrax therapeutics. Here, we describe recent efforts to identify specific and potent LF inhibitors. Derivatization of peptide substrate analogs bearing zinc-binding groups has produced potent and specific LF inhibitors, and X-ray crystallography of LFinhibitor complexes has provided insight into features required for high affinity binding. Novel inhibitor scaffolds have been identified through several approaches, including fragment-based drug discovery, virtual screening, and highthroughput screening of diverse compound libraries. Lastly, efforts to discover LF inhibitors have led to the development of new screening strategies, such as the use of full-length proteins as substrates, that may prove useful for other proteases as well. Overall, these efforts have led to a collection of chemically and mechanistically diverse molecules capable of inhibiting LF activity in vitro and in cells, as well as in animal models of anthrax infection. PMID:27072692

  9. Monoamine Reuptake Inhibitors in Parkinson's Disease

    PubMed Central

    Huot, Philippe; Fox, Susan H.; Brotchie, Jonathan M.

    2015-01-01

    The motor manifestations of Parkinson's disease (PD) are secondary to a dopamine deficiency in the striatum. However, the degenerative process in PD is not limited to the dopaminergic system and also affects serotonergic and noradrenergic neurons. Because they can increase monoamine levels throughout the brain, monoamine reuptake inhibitors (MAUIs) represent potential therapeutic agents in PD. However, they are seldom used in clinical practice other than as antidepressants and wake-promoting agents. This review article summarises all of the available literature on use of 50 MAUIs in PD. The compounds are divided according to their relative potency for each of the monoamine transporters. Despite wide discrepancy in the methodology of the studies reviewed, the following conclusions can be drawn: (1) selective serotonin transporter (SERT), selective noradrenaline transporter (NET), and dual SERT/NET inhibitors are effective against PD depression; (2) selective dopamine transporter (DAT) and dual DAT/NET inhibitors exert an anti-Parkinsonian effect when administered as monotherapy but do not enhance the anti-Parkinsonian actions of L-3,4-dihydroxyphenylalanine (L-DOPA); (3) dual DAT/SERT inhibitors might enhance the anti-Parkinsonian actions of L-DOPA without worsening dyskinesia; (4) triple DAT/NET/SERT inhibitors might exert an anti-Parkinsonian action as monotherapy and might enhance the anti-Parkinsonian effects of L-DOPA, though at the expense of worsening dyskinesia. PMID:25810948

  10. Novel hemagglutinin-based influenza virus inhibitors

    PubMed Central

    Shen, Xintian; Zhang, Xuanxuan

    2013-01-01

    Influenza virus has caused seasonal epidemics and worldwide pandemics, which caused tremendous loss of human lives and socioeconomics. Nowadays, only two classes of anti-influenza drugs, M2 ion channel inhibitors and neuraminidase inhibitors respectively, are used for prophylaxis and treatment of influenza virus infection. Unfortunately, influenza virus strains resistant to one or all of those drugs emerge frequently. Hemagglutinin (HA), the glycoprotein in influenza virus envelope, plays a critical role in viral binding, fusion and entry processes. Therefore, HA is a promising target for developing anti-influenza drugs, which block the initial entry step of viral life cycle. Here we reviewed recent understanding of conformational changes of HA in protein folding and fusion processes, and the discovery of HA-based influenza entry inhibitors, which may provide more choices for preventing and controlling potential pandemics caused by multi-resistant influenza viruses. PMID:23977436

  11. Functional non-nucleoside adenylyl cyclase inhibitors.

    PubMed

    Lelle, Marco; Hameed, Abdul; Ackermann, Lisa-Maria; Kaloyanova, Stefka; Wagner, Manfred; Berisha, Filip; Nikolaev, Viacheslav O; Peneva, Kalina

    2015-05-01

    In this study, we describe the synthesis of novel functional non-nucleoside adenylyl cyclase inhibitors, which can be easily modified with thiol containing biomolecules such as tumour targeting structures. The linkage between inhibitor and biomolecule contains cleavable bonds to enable efficient intracellular delivery in the reductive milieu of the cytosol as well as in the acidic environment within endosomes and lysosomes. The suitability of this synthetic approach was shown by the successful bioconjugation of a poor cell-permeable inhibitor with a cell-penetrating peptide. Additionally, we have demonstrated the excellent inhibitory effect of the compounds presented here in a live-cell Förster resonance energy transfer-based assay in human embryonic kidney cells. PMID:25319071

  12. Serotonin norepinephrine reuptake inhibitors: a pharmacological comparison.

    PubMed

    Sansone, Randy A; Sansone, Lori A

    2014-03-01

    The serotonin norepinephrine reuptake inhibitors are a family of antidepressants that inhibit the reuptake of both serotonin and norepinephrine. While these drugs are traditionally considered a group of inter-related antidepressants based upon reuptake inhibition, they generally display different chemical structures as well as different pharmacological properties. In this article, we discuss these and other differences among the serotonin norepinephrine reuptake inhibitors, including the year of approval by the United States Food and Drug Administration, generic availability, approved clinical indications, half-lives, metabolism and excretion, presence or not of active metabolites, dosing schedules, proportionate effects on serotonin and norepinephrine, and the timing of serotonin and norepinephrine reuptake (i.e., sequential or simultaneous). Again, while serotonin norepinephrine reuptake inhibitors are grouped as a family of antidepressants, they exhibit a surprising number of differences- differences that may ultimately relate to clinical nuances in patient care. PMID:24800132

  13. Topoisomerase I inhibitors: camptothecins and beyond.

    PubMed

    Pommier, Yves

    2006-10-01

    Nuclear DNA topoisomerase I (TOP1) is an essential human enzyme. It is the only known target of the alkaloid camptothecin, from which the potent anticancer agents irinotecan and topotecan are derived. As camptothecins bind at the interface of the TOP1-DNA complex, they represent a paradigm for interfacial inhibitors that reversibly trap macromolecular complexes. Several camptothecin and non-camptothecin derivatives are being developed to further increase anti-tumour activity and reduce side effects. The mechanisms and molecular determinants of tumour response to TOP1 inhibitors are reviewed, and rational combinations of TOP1 inhibitors with other drugs are considered based on current knowledge of repair and checkpoint pathways that are associated with TOP1-mediated DNA damage. PMID:16990856

  14. Orally Bioavailable Potent Soluble Epoxide Hydrolase Inhibitors

    PubMed Central

    Hwang, Sung Hee; Tsai, Hsing-Ju; Liu, Jun-Yan; Morisseau, Christophe; Hammock, Bruce D.

    2008-01-01

    A series of N,N′-disubstituted ureas having a conformationally restricted cis- or trans-1,4-cyclohexane α to the urea were prepared and tested as soluble epoxide hydrolase (sEH) inhibitors. This series of compounds showed low nanomolar to picomolar activities against recombinant human sEH. Both isomers showed similar potencies, but the trans isomers were more metabolically stable in human hepatic microsomes. Furthermore, these new potent inhibitors show a greater metabolic stability in vivo than previously described sEH inhibitors. We demonstrated that trans-4-[4-(3-adamantan-1-ylureido)cyclohexyloxy]benzoic acid 13g (t-AUCB, IC50 = 1.3 ± 0.05 nM) had excellent oral bioavailability (98%, n = 2) and blood area under the curve in dogs and was effective in vivo to treat hypotension in lipopolysaccharide challenged murine models. PMID:17616115

  15. Use of acetylcholinesterase inhibitors in Alzheimer's disease.

    PubMed

    Moghul, S; Wilkinson, D

    2001-09-01

    Alzheimer's disease is a growing problem in an aging Western world, estimated to have cost the US economy USD 1.75 trillion. Until recently, the management of Alzheimer's disease largely comprised support for the family, nursing care and the use of unlicensed medication to control behavioral disturbances. The three new acetylcholinesterase inhibitors licensed to treat Alzheimer's disease (donepezil, rivastigmine and galantamine) have provided clinicians with a major impetus to their desire to diagnose and treat this lethal disease. Their effects on cognition are proven. More recent work on the effects of acetylcholinesterase inhibitors on behavioral symptoms, activities of daily living and caregiver burden have also been encouraging. Emerging work indicates their likely efficacy in other dementias (e.g., vascular dementia, dementia with Lewy bodies). This review summarizes the evidence concerning the impact of acetylcholinesterase inhibitors in dementia both currently and over the next 5 years. PMID:19811047

  16. LDL cholesterol, statins and PCSK 9 inhibitors.

    PubMed

    Gupta, Sanjiv

    2015-01-01

    Reduction of low density lipoprotein cholesterol (LDLc) is of vital importance for the prevention of atherosclerotic cardiovascular disease (ASCVD). Statin is the most effective therapy today to lower LDLc by inhibiting HMG-CoA-reductase. However despite intensive statin therapy, there remains a residual risk of recurrent myocardial infarction in about 20-30% cases. Moreover a few patients develop statin intolerance. For severe hypercholesterolemia, statins alone or in combination of ezetimibe, niacin and fenofibrate have been advocated. For homozygous familial hypercholesterolemia (HOFH), a microsomal triglyceride transfer protein MTP inhibitor (Lopitamide) and antisense oligonucleotide (ASO) (Mipomersen) have recently been approved by FDA, USA through 'Risk evaluation and Mitigation Strategy (REMS)'. Possible future therapies include PCSK-9 inhibitors which have excellent lipid lowering properties. Three monoclonal antibodies (PCSK 9 Inhibitors) alirocumab, evolocumab and Bococizumab are under advanced clinical stage IV trials and awaiting approval by FDA and European Medicines Agency. PMID:26432726

  17. Synthesis of amino heterocycle aspartyl protease inhibitors.

    PubMed

    Chambers, Rachel K; Khan, Tanweer A; Olsen, David B; Sleebs, Brad E

    2016-06-14

    Aspartyl proteases are important pharmacological targets. Historically aspartyl proteases have been commonly targeted with transition state derived peptidomimetics. The strategy to develop aspartyl protease inhibitors has undertaken a dramatic paradigm shift in the last 10 years. The pharmaceutical industry in 2005 disclosed several scaffolds or "head groups" that prompted the field to move beyond peptidomimetic derived inhibitors. Since the discovery of the first amino heterocycle aspartyl protease inhibitor, the amino hydantoin, industry and academia have positioned themselves for a foothold on the new molecular space, designing a variety of related "head groups". Both the design and synthetic efforts involved in constructing these scaffolds are varied and complex. Here we highlight the synthetic strategies used to access these amino heterocycle scaffolds. PMID:27143279

  18. Prospects for novel inhibitors of peptidoglycan transglycosylases

    PubMed Central

    Galley, Nicola F.; O’Reilly, Amy M.; Roper, David I.

    2014-01-01

    The lack of novel antimicrobial drugs under development coupled with the increasing occurrence of resistance to existing antibiotics by community and hospital acquired infections is of grave concern. The targeting of biosynthesis of the peptidoglycan component of the bacterial cell wall has proven to be clinically valuable but relatively little therapeutic development has been directed towards the transglycosylase step of this process. Advances towards the isolation of new antimicrobials that target transglycosylase activity will rely on the development of the enzymological tools required to identify and characterise novel inhibitors of these enzymes. Therefore, in this article, we review the assay methods developed for transglycosylases and review recent novel chemical inhibitors discovered in relation to both the lipidic substrates and natural product inhibitors of the transglycosylase step. PMID:24924926

  19. Global Metabolic Inhibitors of Sialyl- and Fucosyltransferases

    PubMed Central

    Rillahan, Cory D.; Antonopoulos, Aristotelis; Lefort, Craig T.; Sonon, Roberto; Azadi, Parastoo; Ley, Klaus; Dell, Anne; Haslam, Stuart M.; Paulson, James C.

    2012-01-01

    Despite the fundamental roles of sialyl- and fucosyltransferases in mammalian physiology, there are few pharmacological tools to manipulate their function in a cellular setting. Although fluorinated analogs of the donor substrates are well-established transition state inhibitors of these enzymes, they are not membrane permeable. By exploiting promiscuous monosaccharide salvage pathways, we show that fluorinated analogs of sialic acid and fucose can be taken up and metabolized to the desired donor substrate-based inhibitors inside the cell. Due to the existence of metabolic feedback loops, they also act to prevent the de novo synthesis of the natural substrates, resulting in a global, family-wide shutdown of sialyl- and/or fucosyltransferases and remodeling of cell surface glycans. As an example of the functional consequences, the inhibitors drastically reduce expression of the sialylated and fucosylated ligand Sialyl Lewis X on myeloid cells, resulting in loss of binding to selectins and impaired leukocyte rolling. PMID:22683610

  20. Therapeutic potential of monoacylglycerol lipase inhibitors.

    PubMed

    Mulvihill, Melinda M; Nomura, Daniel K

    2013-03-19

    Marijuana and aspirin have been used for millennia to treat a wide range of maladies including pain and inflammation. Both cannabinoids, like marijuana, that exert anti-inflammatory action through stimulating cannabinoid receptors, and cyclooxygenase (COX) inhibitors, like aspirin, that suppress pro-inflammatory eicosanoid production have shown beneficial outcomes in mouse models of neurodegenerative diseases and cancer. Both cannabinoids and COX inhibitors, however, have untoward effects that discourage their chronic usage, including cognitive deficits and gastrointestinal toxicity, respectively. Recent studies have uncovered that the serine hydrolase monoacylglycerol lipase (MAGL) links the endocannabinoid and eicosanoid systems together through hydrolysis of the endocannabinoid 2-arachidonoylglycerol (2-AG) to provide the major arachidonic acid (AA) precursor pools for pro-inflammatory eicosanoid synthesis in specific tissues. Studies in recent years have shown that MAGL inhibitors elicit anti-nociceptive, anxiolytic, and anti-emetic responses and attenuate precipitated withdrawal symptoms in addiction paradigms through enhancing endocannabinoid signaling. MAGL inhibitors have also been shown to exert anti-inflammatory action in the brain and protect against neurodegeneration through lowering eicosanoid production. In cancer, MAGL inhibitors have been shown to have anti-cancer properties not only through modulating the endocannabinoid-eicosanoid network, but also by controlling fatty acid release for the synthesis of protumorigenic signaling lipids. Thus, MAGL serves as a critical node in simultaneously coordinating multiple lipid signaling pathways in both physiological and disease contexts. This review will discuss the diverse (patho)physiological roles of MAGL and the therapeutic potential of MAGL inhibitors in treating a vast array of complex human diseases. PMID:23142242

  1. Substituted quinolines as noncovalent proteasome inhibitors.

    PubMed

    McDaniel, Tanner J; Lansdell, Theresa A; Dissanayake, Amila A; Azevedo, Lauren M; Claes, Jacob; Odom, Aaron L; Tepe, Jetze J

    2016-06-01

    Screening of a library of diverse heterocyclic scaffolds identified substituted quinolines as inhibitors of the human proteasome. The heterocyclic library was prepared via a novel titanium-catalyzed multicomponent coupling reaction, which rendered a diverse set of isoxazoles, pyrimidines, pyrroles, pyrazoles and quinolines. SAR of the parent lead compound indicated that hydrophobic residues on the benzo-moiety significantly improved potency. Lead compound 25 inhibits the chymotryptic-like proteolytic activity of the proteasome (IC50 5.4μM), representing a new class of nonpeptidic, noncovalent proteasome inhibitors. PMID:27112450

  2. Selective serotonin reuptake inhibitor discontinuation during pregnancy

    PubMed Central

    Ejaz, Resham; Leibson, Tom; Koren, Gideon

    2014-01-01

    Abstract Question I have a patient who discontinued her selective serotonin reuptake inhibitor in pregnancy against my advice owing to fears it might affect the baby. She eventually attempted suicide. How can we deal effectively with this situation? Answer The “cold turkey” discontinuation of needed antidepressants is a serious public health issue strengthened by fears and misinformation. It is very important for physicians to ensure that evidence-based information is given to women in a way that is easy to understand. The risks of untreated moderate to severe depression far outweigh the theoretical risks of taking selective serotonin reuptake inhibitors. PMID:25642484

  3. Hereditary angioedema with normal C1 inhibitor.

    PubMed

    Bork, Konrad

    2013-11-01

    Until recently it was assumed that hereditary angioedema was a disease that results exclusively from a genetic deficiency of the C1 inhibitor. In 2000, families with hereditary angioedema, normal C1 inhibitor activity, and protein in plasma were described. Since then, numerous patients and families with that condition have been reported. Most of the patients were women. In many of the affected women, oral contraceptives, hormone replacement therapy containing estrogens, and pregnancies triggered the clinical symptoms. In some families mutations in the coagulation factor XII (Hageman factor) gene were detected. PMID:24176211

  4. Identification of potent, selective KDM5 inhibitors.

    PubMed

    Gehling, Victor S; Bellon, Steven F; Harmange, Jean-Christophe; LeBlanc, Yves; Poy, Florence; Odate, Shobu; Buker, Shane; Lan, Fei; Arora, Shilpi; Williamson, Kaylyn E; Sandy, Peter; Cummings, Richard T; Bailey, Christopher M; Bergeron, Louise; Mao, Weifeng; Gustafson, Amy; Liu, Yichin; VanderPorten, Erica; Audia, James E; Trojer, Patrick; Albrecht, Brian K

    2016-09-01

    This communication describes the identification and optimization of a series of pan-KDM5 inhibitors derived from compound 1, a hit initially identified against KDM4C. Compound 1 was optimized to afford compound 20, a 10nM inhibitor of KDM5A. Compound 20 is highly selective for the KDM5 enzymes versus other histone lysine demethylases and demonstrates activity in a cellular assay measuring the increase in global histone 3 lysine 4 tri-methylation (H3K4me3). In addition compound 20 has good ADME properties, excellent mouse PK, and is a suitable starting point for further optimization. PMID:27476424

  5. HIV Entry Inhibitors and Their Potential in HIV Therapy

    PubMed Central

    Qian, Keduo; Morris-Natschke, Susan L.; Lee, Kuo-Hsiung

    2013-01-01

    This review discusses recent progress in the development of anti-HIV agents targeting the viral entry process. The three main classes (attachment inhibitors, co-receptor binding inhibitors, and fusion inhibitors) are further broken down by specific mechanism of action and structure. Many of these inhibitors are in advanced clinical trials, including the HIV maturation inhibitor bevirimat, from the authors’ laboratories. In addition, the CCR5 inhibitor maraviroc has recently been FDA-approved. Possible roles for these agents in anti-HIV therapy, including treatment of virus resistant to current drugs, are also discussed. PMID:18720513

  6. Polyphenolic Compounds as Pancreatic Lipase Inhibitors.

    PubMed

    Buchholz, Tina; Melzig, Matthias F

    2015-07-01

    Obesity and its associated diseases such as diabetes mellitus and coronary heart diseases are a major challenge for our society. An important target for the treatment of obesity includes the development of inhibitors of nutrient digestion and absorption. Inhibition of pancreatic lipase and the associated reduction of lipid absorption is an attractive approach for the discovery of potent agents. Currently, the only clinically approved pharmacologic agent as pancreatic lipase inhibitor is Orlistat. However, its usage is compromised by unpleasant gastrointestinal adverse reactions (oily stools, oily spotting, flatulence). The use of botanical materials as a potential source of new drugs is of increasing importance and application. Natural products that are interesting for obesity treatment are generally considered to have less toxic and side effects than totally synthetic drugs. One of the most important sources of potential pancreatic lipase inhibitors represents the class of polyphenols. This article summarizes most studied subclasses of polyphenols including flavonoids, hydroxycinnamic acids, hydroxybenzoic acids and lignans with pancreatic lipase inhibitory effects. A structural comparison of potent inhibitors shows an increased inhibitory effect depending on number and position of phenolic hydroxyl groups, degree of polymerization and elimination of glycosylation during digestion. PMID:26132857

  7. Novel proteinase inhibitor promotes resistance to insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel Beta vulgaris serine proteinase inhibitor gene (BvSTI) and its protein are identified in response to insect feeding on B. vulgaris seedlings. BvSTI is cloned into an expression vector with constitutive promoter and transformed into Nicotiana benthamiana plants to assess BvSTI’s ability to ...

  8. Cardiovascular effects of dipeptidyl peptidase-4 inhibitors

    PubMed Central

    Papagianni, M; Tziomalos, K

    2015-01-01

    Dipeptidyl peptidase-4 (DPP-4) inhibitors are effective glucose-lowering agents that do not increase body weight and are associated with a low risk for hypoglycemia. Also, they appear to exert beneficial effects on other established cardiovascular risk factors, including dyslipidemia and hypertension. Moreover, DPP-4 inhibitors exert antiinflammatory and antioxidant actions, improve endothelial function and reduce urinary albumin excretion. In contrast to these favorable cardiovascular effects, three recent large, randomized, placebo-controlled trials in patients with type 2 diabetes mellitus (T2DM) and established cardiovascular disease or multiple cardiovascular risk factors showed that DPP-4 inhibitors do not affect the risk of myocardial infarction or ischemic stroke and might increase the risk of heart failure. The findings of the former randomized studies highlight the limitations of surrogate markers and show that beneficial effects on cardiovascular risk factors do not necessarily translate into reductions in hard clinical endpoints. Ongoing trials will shed more light on the safety profile of DPP-4 inhibitors and will clarify whether they will improve the cardiovascular outcomes of patients with T2DM. Hippokratia 2015; 19 (3): 195-199. PMID:27418775

  9. Histidines, histamines and imidazoles as glycosidase inhibitors.

    PubMed Central

    Field, R A; Haines, A H; Chrystal, E J; Luszniak, M C

    1991-01-01

    This present study reports the ability of a range of derivatives of L-histidine, histamine and imidazole to act as inhibitors of sweet-almond beta-glucosidase, yeast alpha-glucosidase and Escherichia coli beta-galactosidase. The addition of a hydrophobic group to the basic imidazole nucleus greatly enhances binding to both the alpha- and beta-glucosidases. L-Histidine (beta-naphthylamide (Ki 17 microM) is a potent competitive inhibitor of sweet-almond beta-glucosidase as is omega-N-acetylhistamine (K1 35 microM), which inhibits the sweet-almond beta-glucosidase at least 700 times more strongly than either yeast alpha-glucosidase or Escherichia coli beta-galactosidase, and suggests potential for the development of selective reversible beta-glucosidase inhibitors. A range of hydrophobic omega-N-acylhistamines were synthesized and shown to be among the most potent inhibitors of sweet-almond beta-glucosidase reported to date. PMID:2012615

  10. A chemotactic inhibitor in synovial fluid.

    PubMed Central

    Matzner, Y; Partridge, R E; Babior, B M

    1983-01-01

    Synovial fluid was found to contain an inhibitor of neutrophil chemotaxis. The activity of this inhibitor was masked in native synovial fluid, but could be detected in fluid in which complement had been deactivated by mild heating. The inhibitor was most effective against the chemotactic activity of zymosan-activated serum (C5ades arg). It had little effect when N-formyl-methionyl-leucyl-phenylalanine served as chemoattractant. Inhibition was not the result of a direct effect on the neutrophils, since incubation of cells with synovial fluid did not alter their chemotactic response. The inhibitory activity was destroyed by boiling the synovial fluid or treating it with trypsin, suggesting that it is a protein (or proteins); it was not affected by hyaluronidase treatment. Gel filtration revealed that the inhibitor was present in native as well as decomplemented synovial fluid, and that its molecular weight was in the vicinity of 25,000. It is proposed that this inhibitory activity plays a role in the regulation of the inflammatory response in joints. PMID:6840801

  11. Resistant mechanisms to BRAF inhibitors in melanoma.

    PubMed

    Manzano, José Luís; Layos, Laura; Bugés, Cristina; de Los Llanos Gil, María; Vila, Laia; Martínez-Balibrea, Eva; Martínez-Cardús, Anna

    2016-06-01

    Patients with advanced melanoma have traditionally had very poor prognosis. However, since 2011 better understanding of the biology and epidemiology of this disease has revolutionized its treatment, with newer therapies becoming available. These newer therapies can be classified into immunotherapy and targeted therapy. The immunotherapy arsenal includes inhibitors of CTLA4, PD-1 and PDL-1, while targeted therapy focuses on BRAF and MEK. BRAF inhibitors (vemurafenib, dabrafenib) have shown benefit in terms of overall survival (OS) compared to chemotherapy, and their combination with MEK inhibitors has recently been shown to improve progression-free survival (PFS), compared with monotherapy with BRAF inhibitors. However, almost 20% of patients initially do not respond, due to intrinsic resistance to therapy and, of those who do, most eventually develop mechanisms of acquired resistance, including reactivation of the MAP kinase pathway, persistent activation of receptor tyrosine kinase (RTKS) receptor, activation of phosphatidyinositol-3OH kinase, overexpression of epidermal growth factor receptor (EGFR), and interactions with the tumor microenvironment. Herein we comment in detail on mechanisms of resistance to targeted therapy and discuss the strategies to overcome them. PMID:27429963

  12. Cellulose biosynthesis inhibitors - a multifunctional toolbox.

    PubMed

    Tateno, Mizuki; Brabham, Chad; DeBolt, Seth

    2016-01-01

    In the current review, we examine the growing number of existing Cellulose Biosynthesis Inhibitors (CBIs) and based on those that have been studied with live cell imaging we group their mechanism of action. Attention is paid to the use of CBIs as tools to ask fundamental questions about cellulose biosynthesis. PMID:26590309

  13. FAAH inhibitors in the limelight, but regrettably

    PubMed Central

    Mallet, Christophe; Dubray, Claude; Dualé, Christian

    2016-01-01

    Abstract. This short review focuses on the recent drug development of FAAH inhibitors, as recent serious adverse events have been reported in a phase I study with a compound of this class. The authors overview the potential interest in targeting FAAH inhibition, the current programs, and the available information on the recent dramatic events. PMID:27191771

  14. Phenyltriazolinones as potent factor Xa inhibitors.

    PubMed

    Quan, Mimi L; Pinto, Donald J P; Rossi, Karen A; Sheriff, Steven; Alexander, Richard S; Amparo, Eugene; Kish, Kevin; Knabb, Robert M; Luettgen, Joseph M; Morin, Paul; Smallwood, Angela; Woerner, Francis J; Wexler, Ruth R

    2010-02-15

    We have discovered that phenyltriazolinone is a novel and potent P1 moiety for coagulation factor Xa. X-ray structures of the inhibitors with a phenyltriazolinone in the P1 position revealed that the side chain of Asp189 has reoriented resulting in a novel S1 binding pocket which is larger in size to accommodate the phenyltriazolinone P1 substrate. PMID:20100660

  15. Photodynamic therapy using a protoporphyrinogen oxidase inhibitor.

    PubMed

    Fingar, V H; Wieman, T J; McMahon, K S; Haydon, P S; Halling, B P; Yuhas, D A; Winkelman, J W

    1997-10-15

    The use of endogenously created porphyrins as an alternative to photosensitizer injection for photodynamic therapy is a rapidly evolving area of study. One common method to induce porphyrin synthesis and accumulation in cells is the topical, oral, or parenteral administration of 5-aminolevulinic acid, a precursor for heme biosynthesis. Porphyrin accumulation may also be elicited by the use of enzyme inhibitors of the heme biosynthetic pathway. Groups of DBA/2 mice bearing SMT-F mammary tumors were placed on a diet containing 0-4000 ppm of a protoporphyrinogen oxidase inhibitor, FP-846. This agent blocks a critical step in porphyrin metabolism and results in elevated intracellular levels of protoporphyrin IX. Light treatment of tumors produced both initial and long-term regression that was dependent on the amount of inhibitor, the duration of inhibitor exposure to animals, and the amount of light used in PDT. Tumor regression occurred without significant destruction of normal tissues in the treatment field and without initial vascular constriction or blood flow stasis. Tumor cure in animals given 4000 ppm FP-846 in feed for 3 days and 300 J/cm2 602-670 nm light (23% cure) was similar to the response in animals given 10 mg/kg Photofrin and the same light dose (20%). PMID:9377568

  16. Resistant mechanisms to BRAF inhibitors in melanoma

    PubMed Central

    Layos, Laura; Bugés, Cristina; de los Llanos Gil, María; Vila, Laia; Martínez-Balibrea, Eva; Martínez-Cardús, Anna

    2016-01-01

    Patients with advanced melanoma have traditionally had very poor prognosis. However, since 2011 better understanding of the biology and epidemiology of this disease has revolutionized its treatment, with newer therapies becoming available. These newer therapies can be classified into immunotherapy and targeted therapy. The immunotherapy arsenal includes inhibitors of CTLA4, PD-1 and PDL-1, while targeted therapy focuses on BRAF and MEK. BRAF inhibitors (vemurafenib, dabrafenib) have shown benefit in terms of overall survival (OS) compared to chemotherapy, and their combination with MEK inhibitors has recently been shown to improve progression-free survival (PFS), compared with monotherapy with BRAF inhibitors. However, almost 20% of patients initially do not respond, due to intrinsic resistance to therapy and, of those who do, most eventually develop mechanisms of acquired resistance, including reactivation of the MAP kinase pathway, persistent activation of receptor tyrosine kinase (RTKS) receptor, activation of phosphatidyinositol-3OH kinase, overexpression of epidermal growth factor receptor (EGFR), and interactions with the tumor microenvironment. Herein we comment in detail on mechanisms of resistance to targeted therapy and discuss the strategies to overcome them. PMID:27429963

  17. [Myoclonic encephalopathy associated with proton pump inhibitors].

    PubMed

    Boulliat, J; Polard, E; Colin, F; Bentué-Ferrer, D; Allain, H

    2004-03-01

    Two men (66 and 73 Years) with a cardiovascular history were hospitalized for rapid onset encephalopathy associated with myoclonia and an extrapyramidal syndrome. On the basis of the French Pharmacovigilance system, this symptomatology has been attributed to the coadministration of a proton pump inhibitor, lansoprazole (15mg/day) with levodopa. Lansoprazole withdrawal led to a normalisation of the situation. PMID:15037850

  18. Novel in vitro inhibitory functions of potato tuber proteinaceous inhibitors.

    PubMed

    Fischer, Matthias; Kuckenberg, Markus; Kastilan, Robin; Muth, Jost; Gebhardt, Christiane

    2015-02-01

    Plant protease inhibitors are a structurally highly diverse and ubiquitous class of small proteins, which play various roles in plant development and defense against pests and pathogens. Particular isoforms inhibit in vitro proteases and other enzymes that are not their natural substrates, for example proteases that have roles in human diseases. Mature potato tubers are a rich source of several protease inhibitor families. Different cultivars have different inhibitor profiles. With the objective to explore the functional diversity of the natural diversity of potato protease inhibitors, we randomly selected and sequenced 9,600 cDNA clones originated from mature tubers of ten potato cultivars. Among these, 120 unique inhibitor cDNA clones were identified by homology searches. Eighty-eight inhibitors represented novel sequence variants of known plant protease inhibitor families. Most frequent were Kunitz-type inhibitors (KTI), potato protease inhibitors I and II (PIN), pectin methylesterase inhibitors, metallocarboxypeptidase inhibitors and defensins. Twenty-three inhibitors were functionally characterized after heterologous expression in the yeast Pichia pastoris. The purified recombinant proteins were tested for inhibitory activity on trypsin, eleven pharmacological relevant proteases and the non-proteolytic enzyme 5-lipoxygenase. Members of the KTI and PIN families inhibited pig pancreas elastase, β-Secretase, Cathepsin K, HIV-1 protease and potato 5-lipoxygenase. Our results demonstrate in vitro inhibitory diversity of small potato tuber proteins commonly known as protease inhibitors, which might have biotechnological or medical applications. PMID:25260821

  19. Cost of care of haemophilia with inhibitors.

    PubMed

    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. PMID:19845772

  20. Inhibitors from Carob (Ceratonia siliqua L.)

    PubMed Central

    Corcoran, Mary Ritzel

    1970-01-01

    Two inhibitory fractions (B1 and C) from extracts of immature fruit of carob were tested for their ability to inhibit the action of indoleacetic acid (IAA) in three bioassays. There was no reduction of IAA-induced reactions in the Avena curvature test, abscission of debladed coleus petioles, or growth of cucumber hypocotyls. The highest ratio of inhibitor to IAA was 10,000 times greater than the ratio necessary to inhibit by 50% the growth caused by an equivalent amount of gibberellin A3 in pea seedlings. At the highest concentration used, fraction C alone caused curvature of Avena coleoptiles. The inhibitory fractions appeared to enhance the effect of IAA in the cucumber test. Concentrated whole extract and fractions B1 and C were tested for reduction of growth caused by gibberellins A1, A4, A5, A7, and a neutral gibberellin-like substance from beans in the dwarf-5 maize bioassay. Each gibberellin was inhibited and required the same amount of inhibitor for a 50% reduction of the induced growth. The inhibiting effect could be completely overcome by increasing the amount of gibberellin while maintaining the same concentration of inhibitor. Fractions B1 and C were also tested with gibberellins A2 and A4 in the cucumber hypocotyl test. Both inhibitory fractions reduced growth but were more effective against gibberellin A3 than gibberellin A4 in the assay. The ability to reduce gibberellin-induced growth and not reduce IAA-induced growth indicates that the inhibitors from carob have a greater specificity of action than that previously reported for any inhibitor. PMID:16657500

  1. DNA Methyltransferases Inhibitors from Natural Sources.

    PubMed

    Zwergel, Clemens; Valente, Sergio; Mai, Antonello

    2016-01-01

    DNA methyltransferases (DNMTs) catalyze the methylation at cytosine-C5 mainly in a CpG dinucleotide context. Although DNA methylation is essential for fundamental processes like embryonic development or differentiation, aberrant expression and/or activities of DNMTs are involved in several pathologies, from neurodegeneration to cancer. DNMTs inhibition can arrest tumor growth, cells invasiveness and induce differentiation, whereas their increased expression is shown in numerous cancer types. Moreover, hypermethylated promoters of tumor suppressor genes lead to their silencing. Hence, the use of specific inhibitors of DNMT might reactivate those genes and stop or even reverse the aberrant cell processes. To date, the only approved DNMTs inhibitors for therapy belong to the nucleoside-based family of drugs, but they display relevant side effects as well as high chemical instability. Thus, there is a keen interest actually exists to develop novel, potent and safe inhibitors possessing a nonnucleoside structure. Increasing literature evidence is highlighting that natural sources could help the researchers to achieve this goal. Indeed, several polyphenols, flavonoids, antraquinones, and others are described able to inhibit DNMTs activity and/or expression, thus decreasing the methylation/silencing of different genes involved in tumorigenesis. These events can lead to re-expression of such genes and to cell death in diverse cancer cell lines. Epigallocatechin-3-gallate (1) and laccaic acid A (11) resulted the most effective DNMT1 inhibitors with submicromolar IC50 values, acting as competitive inhibitors. Compound 1 and 11 both displayed gene demethylation and re-activation in several cancers. However, all of the natural compounds described in this review showed important results, from gene reactivation to cell growth inhibition. Moreover, some of them displayed interesting activity even in rodent cancer models and very recently entered clinical trials. PMID:26303417

  2. Peptidyl cyclopropenones: Reversible inhibitors, irreversible inhibitors, or substrates of cysteine proteases?

    PubMed Central

    Cohen, Meital; Bretler, Uriel; Albeck, Amnon

    2013-01-01

    Peptidyl cyclopropenones were previously introduced as selective cysteine protease reversible inhibitors. In the present study we synthesized one such peptidyl cyclopropenone and investigated its interaction with papain, a prototype cysteine protease. A set of kinetics, biochemical, HPLC, MS, and 13C-NMR experiments revealed that the peptidyl cyclopropenone was an irreversible inhibitor of the enzyme, alkylating the catalytic cysteine. In parallel, this cyclopropenone also behaved as an alternative substrate of the enzyme, providing a product that was tentatively suggested to be either a spiroepoxy cyclopropanone or a gamma-lactone. Thus, a single family of compounds exhibits an unusual variety of activities, being reversible inhibitors, irreversible inhibitors and alternative substrates towards enzymes of the same family. PMID:23553793

  3. Comparative study on the protease inhibitors from fish eggs

    NASA Astrophysics Data System (ADS)

    Ustadi; Kim, K. Y.; Kim, S. M.

    2005-07-01

    The protease inhibitor was purified from five different fish eggs. The molecular weights of Pacific herring, chum salmon, pond smelt, glassfish, and Alaska pollock egg protease inhibitors were 120, 89, 84.5, 17, and l6.8kDa, respectively. The specific inhibitory activity of glassfish egg protease inhibitor was the highest followed by those of Pacific herring and Alaska pollock in order. The specific inhibitory activity and purity of glassfish egg protease inhibitor were 19.70 Umg-1 protein and 164.70 folds of purification, respectively. Glassfish egg protease inhibitor was reasonably stable at 50-65°C and pH 8, which was more stable at high temperature and pH than protease inhibitors from the other fish species. Glassfish egg protease inhibitor was noncompetitive with inhibitor constant ( K i) of 4.44 nmolL-1.

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

    PubMed

    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. PMID:23772801

  5. Development of covalent inhibitors that can overcome resistance to first-generation FGFR kinase inhibitors.

    PubMed

    Tan, Li; Wang, Jun; Tanizaki, Junko; Huang, Zhifeng; Aref, Amir R; Rusan, Maria; Zhu, Su-Jie; Zhang, Yiyun; Ercan, Dalia; Liao, Rachel G; Capelletti, Marzia; Zhou, Wenjun; Hur, Wooyoung; Kim, NamDoo; Sim, Taebo; Gaudet, Suzanne; Barbie, David A; Yeh, Jing-Ruey Joanna; Yun, Cai-Hong; Hammerman, Peter S; Mohammadi, Moosa; Jänne, Pasi A; Gray, Nathanael S

    2014-11-11

    The human FGF receptors (FGFRs) play critical roles in various human cancers, and several FGFR inhibitors are currently under clinical investigation. Resistance usually results from selection for mutant kinases that are impervious to the action of the drug or from up-regulation of compensatory signaling pathways. Preclinical studies have demonstrated that resistance to FGFR inhibitors can be acquired through mutations in the FGFR gatekeeper residue, as clinically observed for FGFR4 in embryonal rhabdomyosarcoma and neuroendocrine breast carcinomas. Here we report on the use of a structure-based drug design to develop two selective, next-generation covalent FGFR inhibitors, the FGFR irreversible inhibitors 2 (FIIN-2) and 3 (FIIN-3). To our knowledge, FIIN-2 and FIIN-3 are the first inhibitors that can potently inhibit the proliferation of cells dependent upon the gatekeeper mutants of FGFR1 or FGFR2, which confer resistance to first-generation clinical FGFR inhibitors such as NVP-BGJ398 and AZD4547. Because of the conformational flexibility of the reactive acrylamide substituent, FIIN-3 has the unprecedented ability to inhibit both the EGF receptor (EGFR) and FGFR covalently by targeting two distinct cysteine residues. We report the cocrystal structure of FGFR4 with FIIN-2, which unexpectedly exhibits a "DFG-out" covalent binding mode. The structural basis for dual FGFR and EGFR targeting by FIIN3 also is illustrated by crystal structures of FIIN-3 bound with FGFR4 V550L and EGFR L858R. These results have important implications for the design of covalent FGFR inhibitors that can overcome clinical resistance and provide the first example, to our knowledge, of a kinase inhibitor that covalently targets cysteines located in different positions within the ATP-binding pocket. PMID:25349422

  6. Development of covalent inhibitors that can overcome resistance to first-generation FGFR kinase inhibitors

    PubMed Central

    Tan, Li; Wang, Jun; Tanizaki, Junko; Huang, Zhifeng; Aref, Amir R.; Rusan, Maria; Zhu, Su-Jie; Zhang, Yiyun; Ercan, Dalia; Liao, Rachel G.; Capelletti, Marzia; Zhou, Wenjun; Hur, Wooyoung; Kim, NamDoo; Sim, Taebo; Gaudet, Suzanne; Barbie, David A.; Yeh, Jing-Ruey Joanna; Yun, Cai-Hong; Hammerman, Peter S.; Mohammadi, Moosa; Jänne, Pasi A.; Gray, Nathanael S.

    2014-01-01

    The human FGF receptors (FGFRs) play critical roles in various human cancers, and several FGFR inhibitors are currently under clinical investigation. Resistance usually results from selection for mutant kinases that are impervious to the action of the drug or from up-regulation of compensatory signaling pathways. Preclinical studies have demonstrated that resistance to FGFR inhibitors can be acquired through mutations in the FGFR gatekeeper residue, as clinically observed for FGFR4 in embryonal rhabdomyosarcoma and neuroendocrine breast carcinomas. Here we report on the use of a structure-based drug design to develop two selective, next-generation covalent FGFR inhibitors, the FGFR irreversible inhibitors 2 (FIIN-2) and 3 (FIIN-3). To our knowledge, FIIN-2 and FIIN-3 are the first inhibitors that can potently inhibit the proliferation of cells dependent upon the gatekeeper mutants of FGFR1 or FGFR2, which confer resistance to first-generation clinical FGFR inhibitors such as NVP-BGJ398 and AZD4547. Because of the conformational flexibility of the reactive acrylamide substituent, FIIN-3 has the unprecedented ability to inhibit both the EGF receptor (EGFR) and FGFR covalently by targeting two distinct cysteine residues. We report the cocrystal structure of FGFR4 with FIIN-2, which unexpectedly exhibits a “DFG-out” covalent binding mode. The structural basis for dual FGFR and EGFR targeting by FIIN3 also is illustrated by crystal structures of FIIN-3 bound with FGFR4 V550L and EGFR L858R. These results have important implications for the design of covalent FGFR inhibitors that can overcome clinical resistance and provide the first example, to our knowledge, of a kinase inhibitor that covalently targets cysteines located in different positions within the ATP-binding pocket. PMID:25349422

  7. Combined effects of EGFR tyrosine kinase inhibitors and vATPase inhibitors in NSCLC cells.

    PubMed

    Jin, Hyeon-Ok; Hong, Sung-Eun; Kim, Chang Soon; Park, Jin-Ah; Kim, Jin-Hee; Kim, Ji-Young; Kim, Bora; Chang, Yoon Hwan; Hong, Seok-Il; Hong, Young Jun; Park, In-Chul; Lee, Jin Kyung

    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. PMID:25981168

  8. Tissue factor pathway inhibitor-2 is a novel inhibitor of matrix metalloproteinases with implications for atherosclerosis

    PubMed Central

    Herman, Michael P.; Sukhova, Galina K.; Kisiel, Walter; Foster, Don; Kehry, Marilyn R.; Libby, Peter; Schönbeck, Uwe

    2001-01-01

    Degradation of ECM, particularly interstitial collagen, promotes plaque instability, rendering atheroma prone to rupture. Previous studies implicated matrix metalloproteinases (MMPs) in these processes, suggesting that dysregulated MMP activity, probably due to imbalance with endogenous inhibitors, promotes complications of atherosclerosis. We report here that the serine proteinase inhibitor tissue factor pathway inhibitor-2 (TFPI-2) can function as an MMP inhibitor. TFPI-2 diminished the ability of the interstitial collagenases MMP-1 and MMP-13 to degrade triple-helical collagen, the primary load-bearing molecule of the ECM within human atheroma. In addition, TFPI-2 also reduced the activity of the gelatinases MMP-2 and MMP-9. In contrast to the “classical” tissue inhibitors of MMPs (TIMPs), TFPI-2 expression in situ correlated inversely with MMP levels in human atheroma. TFPI-2 colocalized primarily with smooth muscle cells in the normal media as well as the plaque’s fibrous cap. Conversely, the macrophage-enriched shoulder region, the prototypical site of matrix degradation and plaque rupture, stained only weakly for TFPI-2 but intensely for gelatinases and interstitial collagenases. Evidently, human mononuclear phagocytes, an abundant source of MMPs within human atheroma, lost their ability to express this inhibitor during differentiation in vitro. These findings establish a new, anti-inflammatory function of TFPI-2 of potential pathophysiological significance for human diseases, including atherosclerosis. PMID:11342575

  9. Action of anti-HIV drugs and resistance: reverse transcriptase inhibitors and protease inhibitors.

    PubMed

    Imamichi, Tomozumi

    2004-01-01

    Currently, 20 drugs have been approved for Human Immunodeficiency Virus type-1 (HIV-1) clinical therapy. These drugs inhibit HIV-1 reverse transcriptase, protease, or virus entry. Introduction of a combination therapy with reverse transcriptase inhibitors and protease inhibitors has resulted in a drastic decrease in HIV-1 related mortality. Although the combination therapy can suppress viral replication below detection levels in current available assays, low levels of on-going viral replication still persist in some patients. Long-term administration of the combination therapy may increase selective pressure against viruses, and subsequently induce emergence of multiple drug-resistant HIV-1 variants. Attempts have been made to design novel antiretroviral drugs that would be able to suppress replication of the resistant variants. At present, several investigational drugs are being tested in clinical trials. These drugs target not only the resistant variants, but also improvement in oral bioavilability or other viral proteins such as HIV-1 integrase, ribonuclease H, and HIV-1 entry (CD4 attachment inhibitors, chemokine receptors antagonists, and fusion inhibitors). Understanding mechanism(s) of action of the drugs and mechanisms of drug resistance is necessary for successful designs in the next generation of anti-HIV-1 drugs. In this review, the mechanisms of action of reverse transcriptase- and protease-inhibitors, and the mechanism of resistance to these inhibitors, are described. PMID:15579086

  10. Disulfide bridge structure of ascidian trypsin inhibitor I: similarity to Kazal-type inhibitors.

    PubMed

    Kumazaki, T; Ishii, S

    1990-03-01

    The primary structures of ascidian trypsin inhibitors (iso-inhibitors I and II) were reported in the preceding paper (Kumazaki, T. et al. (1990) J. Biochem. 107, 409-413). Both of them have eight half-cystines in a molecule composed of 55 amino acid residues with a sequence showing no extensive homology to other known protease inhibitors. To locate the four disulfide bridges in the molecule, native inhibitor I was digested with thermolysin to yield cystine-containing peptides. The peptides were separated from each other by reversed-phase HPLC. A core peptide still containing six closely located half-cystines (e.g. -Cys-Arg-Cys and -Cys-Cys-) was further digested with Streptomyces griseus trypsin for cleavage of the Arg-Cys bond. On the other hand, the Cys-Cys bond was split by applying manual Edman degradation to the core peptide. Amino acid composition analyses of the resulting cystine peptides allowed us to define the whole disulfide bridge structure in the parent molecule. The topological relation between the disulfide loops and the reactive site suggested that the ascidian trypsin inhibitor may be classified as a member of the Kazal-type inhibitor family. PMID:2111316

  11. Studies on amylase inhibitors in some Egyptian legume seeds.

    PubMed

    Shekib, L A; el-Iraqui, S M; Abo-Bakr, T M

    1988-01-01

    Amylase inhibitor activity was determined in four legume seeds which are widely consumed in Egypt. The effect of dehulling, heat treatment, soaking and germination were also assessed. The results showed that faba bean contained the highest activity of amylase inhibitor followed by cowpea, lentils, then chickpea. Dehulling resulted in raising the amylase inhibitor activities in all samples investigated, while heat treatment and cooking lowered it. Soaking for 10 h and germination eliminated completely the inhibitor from all samples. PMID:2467277

  12. Controlled-release scale inhibitor for use in fracturing treatments

    SciTech Connect

    Powell, R.J.; Gdanski, R.D.; McCabe, M.A.; Buster, D.C.

    1995-11-01

    This paper describes results of laboratory and field testing of a solid, controlled-release scale inhibitor for use in fracturing treatments. Laboratory testing with a continuous flow apparatus has yielded inhibitor release rates under dynamic conditions. The inhibitor was tested to determine the minimum inhibitor concentration required to inhibit the formation of CaCO{sub 3}, CaSO{sub 4}, and BaSO{sub 4} scales in a brine. A model to predict the long-term release rate of the inhibitor was developed from data collected on the continuous flow apparatus. Data from treated wells will be compared with predictions of the model. Inhibitor release-rate testing in a continuous-flow apparatus shows that a solid, calcium-magnesium polyphosphate inhibitor has a sustained release profile. Release-rate testing shows that the inhibitor can be used up to 175 F. The inhibitor is compatible with both borate and zirconium crosslinked fracturing fluids and foamed fluids. The effective lifetime of the scale treatment can be predicted based on a model developed from laboratory data. The input variables required for the prediction include: temperature, water production, amount of inhibitor, minimum effective concentration of inhibitor for the specific brine. The model can be used to aid in the design of the scale inhibitor treatment.

  13. Inhibitor analysis for a solar heating and cooling system

    NASA Technical Reports Server (NTRS)

    Tabony, J. H.

    1977-01-01

    A study of potential corrosion inhibitors for the NASA solar heating and cooling system which uses aluminum solar panels is provided. Research consisted of testing using a dynamic corrosion system, along with an economic analysis of proposed corrosion inhibitors. Very good progress was made in finding a suitable inhibitor for the system.

  14. P3 SAR exploration of biphenyl carbamate based Legumain inhibitors.

    PubMed

    Higgins, Catherine; Bouazzaoui, Samira; Gaddale, Kishore; D'Costa, Zenobia; Templeman, Amy; O'Rourke, Martin; Young, Andrew; Scott, Christopher; Harrison, Tim; Mullan, Paul; Williams, Rich

    2014-06-01

    This Letter describes the further development and SAR exploration of a novel series of Legumain inhibitors. Based upon a previously identified Legumain inhibitor from our group, we explored the SAR of the carbamate phenyl ring system to probe the P3 pocket of the enzyme. This led to the identification of a sub-nanomolar inhibitor of Legumain. PMID:24775305

  15. Impact of Wines and Wine Constituents on Cyclooxygenase-1, Cyclooxygenase-2, and 5-Lipoxygenase Catalytic Activity

    PubMed Central

    Temml, Veronika; Maghradze, David; Vanek, Tomas

    2014-01-01

    Cyclooxygenases and lipoxygenases are proinflammatory enzymes; the former affects platelet aggregation, vasoconstriction, vasodilatation and later the development of atherosclerosis. Red wines from Georgia and central and western Europe inhibited cyclooxygenase-1 (COX-1) activity in the range of 63–94%, cyclooxygenase-2 (COX-2) activity in the range of 20–44% (tested at a concentration of 5 mL/L), and 5-lipoxygenase (5-LOX) activity in the range of 72–84% (at a concentration of 18.87 mL/L). White wines inhibited 5-LOX in the range of 41–68% at a concentration of 18.87 mL/L and did not inhibit COX-1 and COX-2. Piceatannol (IC50 = 0.76 μM) was identified as a strong inhibitor of 5-LOX followed by luteolin (IC50 = 2.25 μM), quercetin (IC50 = 3.29 μM), and myricetin (IC50 = 4.02 μM). trans-Resveratrol was identified as an inhibitor of COX-1 (IC50 = 2.27 μM) and COX-2 (IC50 = 3.40 μM). Red wine as a complex mixture is a powerful inhibitor of COX-1, COX-2, and 5-LOX, the enzymes involved in eicosanoid biosynthetic pathway. PMID:24976682

  16. Unveiling new chemical scaffolds as Mnk inhibitors.

    PubMed

    Diab, Sarah; Li, Peng; Basnet, Sunita K C; Lu, Jingfeng; Yu, Mingfeng; Albrecht, Hugo; Milne, Robert W; Wang, Shudong

    2016-01-01

    The discovery of small molecules that selectively inhibit Mnks is considered of paramount importance towards deciphering the exact role of these proteins in carcinogenesis and to further validate them as anti-cancer drug targets. However, the dearth of structural information of Mnks is a major hurdle. This study unveils the 7H-pyrrolo[2,3-d]pyrimidine derivatives as potent inhibitors of Mnks. ATP and substrate competition assays showed that this scaffold interacts with the ATP binding site, but not with the substrate site. Screened against a panel of cancer cells, Mnk inhibitors were most potent against MV4-11 acute myeloid leukemia cells. The induction of apoptosis was shown to be mediated by downregulation of Mcl-1. PMID:26910782

  17. Protein synthesis inhibitor from potato tuber

    SciTech Connect

    Romaen, R. )

    1989-04-01

    A protein fraction capable of inhibit in vitro protein synthesis was found in potato tubers in fresh and wounded tissue. Inhibitor activity from fresh tissue decays with wounding. Inhibition activity was detected absorbed to ribsomal fraction and cytosol of potato tuber tissue by a partially reconstituted in vitro system from potato tuber and wheat germ. Adsorbed ribosomal fraction was more suitable of purification. This fraction was washed from ribosomes with 0.3M KCl, concentrated with ammonium sulfate precipitation and purified through sephadex G100 and sephadex G-75 columns chromatography. After 61 fold purification adsorbed protein fraction can inhibit germination of maize, wheat and sesame seeds, as well as {sup 3}H-leucine incorporation into protein by imbibed maize embryos. Inhibition activity was lost by temperature, alkali and protease-K hydrolysis. Preliminar analysis could not show presence of reductor sugars. Physiological role of this inhibitor in relation to rest and active tissue remains to be studied.

  18. Serine protease inhibitors of parasitic helminths.

    PubMed

    Molehin, Adebayo J; Gobert, Geoffrey N; McManus, Donald P

    2012-05-01

    Serine protease inhibitors (serpins) are a superfamily of structurally conserved proteins that inhibit serine proteases and play key physiological roles in numerous biological systems such as blood coagulation, complement activation and inflammation. A number of serpins have now been identified in parasitic helminths with putative involvement in immune regulation and in parasite survival through interference with the host immune response. This review describes the serpins and smapins (small serine protease inhibitors) that have been identified in Ascaris spp., Brugia malayi, Ancylostoma caninum Onchocerca volvulus, Haemonchus contortus, Trichinella spiralis, Trichostrongylus vitrinus, Anisakis simplex, Trichuris suis, Schistosoma spp., Clonorchis sinensis, Paragonimus westermani and Echinococcus spp. and discusses their possible biological functions, including roles in host-parasite interplay and their evolutionary relationships. PMID:22310379

  19. mTOR inhibitors in cancer therapy

    PubMed Central

    Xie, Jianling; Wang, Xuemin; Proud, Christopher G.

    2016-01-01

    The mammalian target of rapamycin, mTOR, plays key roles in cell growth and proliferation, acting at the catalytic subunit of two protein kinase complexes: mTOR complexes 1 and 2 (mTORC1/2). mTORC1 signaling is switched on by several oncogenic signaling pathways and is accordingly hyperactive in the majority of cancers. Inhibiting mTORC1 signaling has therefore attracted great attention as an anti-cancer therapy. However, progress in using inhibitors of mTOR signaling as therapeutic agents in oncology has been limited by a number of factors, including the fact that the classic mTOR inhibitor, rapamycin, inhibits only some of the effects of mTOR; the existence of several feedback loops; and the crucial importance of mTOR in normal physiology.

  20. Development of inhibitors in the ubiquitination cascade.

    PubMed

    Zhang, Wei; Sidhu, Sachdev S

    2014-01-21

    The ubiquitin proteasome system (UPS) is essential in regulating myriad aspects of protein functions. It is therefore a fundamentally important regulatory mechanism that impacts most if not all aspects of cellular processes. Indeed, malfunction of UPS components is implicated in human diseases such as neurodegenerative and immunological disorders and many cancers. The success of proteasome inhibitors in cancer therapy suggests that modulating enzymes in the ubiquitination cascade would be clinically important for therapeutic benefits. In this review, we summarize advances in developing inhibitors of a variety of UPS components. In particular, we highlight recent work done on the protein engineering of ubiquitin as modulators of the UPS, a novel approach that may shed light on innovative drug discovery in the future. PMID:24239534

  1. Naphthyridines as novel BET family bromodomain inhibitors.

    PubMed

    Mirguet, Olivier; Lamotte, Yann; Chung, Chun-Wa; Bamborough, Paul; Delannée, Delphine; Bouillot, Anne; Gellibert, Françoise; Krysa, Gael; Lewis, Antonia; Witherington, Jason; Huet, Pascal; Dudit, Yann; Trottet, Lionel; Nicodeme, Edwige

    2014-03-01

    Bromodomains (BRDs) are small protein domains found in a variety of proteins that recognize and bind to acetylated histone tails. This binding affects chromatin structure and facilitates the localisation of transcriptional complexes to specific genes, thereby regulating epigenetically controlled processes including gene transcription and mRNA elongation. Inhibitors of the bromodomain and extra-terminal (BET) proteins BRD2-4 and T, which prevent bromodomain binding to acetyl-modified histone tails, have shown therapeutic promise in several diseases. We report here the discovery of 1,5-naphthyridine derivatives as potent inhibitors of the BET bromodomain family with good cell activity and oral pharmacokinetic parameters. X-ray crystal structures of naphthyridine isomers have been solved and quantum mechanical calculations have been used to explain the higher affinity of the 1,5-isomer over the others. The best compounds were progressed in a mouse model of inflammation and exhibited dose-dependent anti-inflammatory pharmacology. PMID:24000170

  2. Replacing sulfa drugs with novel DHPS inhibitors

    PubMed Central

    Hammoudeh, Dalia I; Zhao, Ying; White, Stephen W; Lee, Richard E

    2013-01-01

    More research effort needs to be invested in antimicrobial drug development to address the increasing threat of multidrug-resistant organisms. The enzyme DHPS has been a validated drug target for over 70 years as the target for the highly successful sulfa drugs. The use of sulfa drugs has been compromised by the widespread presence of resistant organisms and the adverse side effects associated with their use. Despite the large amount of structural information available for DHPS, few recent publications address the possibility of using this knowledge for novel drug design. This article reviews the relevant papers and patents that report promising new small-molecule inhibitors of DHPS, and discuss these data in light of new insights into the DHPS catalytic mechanism and recently determined crystal structures of DHPS bound to potent small-molecule inhibitors. This new functional understanding confirms that DHPS deserves further consideration as an antimicrobial drug target. PMID:23859210

  3. [Once-weekly DPP-4 inhibitor].

    PubMed

    Harada, Norio; Inagaki, Nobuya

    2015-12-01

    Trelagliptin is the first once-weekly dipeptidyl peptidase-4(DPP-4) inhibitor in the world. Trelagliptin inhibits DPP-4 activity with lower drug concentration compared with other once- (or twice-) daily DPP-4 inhibitors in in vitro study. More than 70 % of DPP-4 activity is inhibited even 1 week after administration of trelagliptin administration in human study. 24-week trelagliptin monotherapy improved HbA1c(-0.33%) and fasting plasma glucose levels in Japanese patients with type 2 diabetes. Trelagliptin did not affect body weight and frequency of hypoglycemic events in this study. 52-week monotherapy and add-on therapy of trelagliptin also improved HbA1c levels without body weight gain and severe hypoglycemia. Therefore, trelagliptin has high efficacy and safety on glucose control in Japanese patients with type 2 diabetes. PMID:26666159

  4. New potential AChE inhibitor candidates.

    PubMed

    de Paula, A A N; Martins, J B L; dos Santos, M L; Nascente, L de C; Romeiro, L A S; Areas, T F M A; Vieira, K S T; Gambôa, N F; Castro, N G; Gargano, R

    2009-09-01

    We have theoretically studied new potential candidates of acetylcholinesterase (AChE) inhibitors designed from cardanol, a non-isoprenoid phenolic lipid of cashew Anacardium occidentale nut-shell liquid. The electronic structure calculations of fifteen molecule derivatives from cardanol were performed using B3LYP level with 6-31G, 6-31G(d), and 6-311+G(2d,p) basis functions. For this study we used the following groups: methyl, acetyl, N,N-dimethylcarbamoyl, N,N-dimethylamine, N,N-diethylamine, piperidine, pyrrolidine, and N,N-methylbenzylamine. Among the proposed compounds we identified that the structures with substitution by N,N-dimethycarbamoyl, N,N-dimethylamine, and pyrrolidine groups were better correlated to rivastigmine, and represent possible AChE inhibitors against Alzheimer disease. PMID:19446931

  5. Inhibitor prevents corrosion, scale in Chinese waterflood

    SciTech Connect

    Yong, W.; Jianhua, W. )

    1994-03-14

    An imidazoline derivative-based series inhibitor has prevented both corrosion and scale formation in produced-water treatment and water-injection equipment in China National Petroleum Co.'s (CNPC) Shengli oil field. Development of the inhibitor started in 1986, and after successful field trials the chemical is now being extensively applied. To increase oil recovery, water injection is widely used in China's onshore oil fields. Oil production in the Shengli oil field, for example, requires injection of about 4 bbl of water/1 bbl of oil produced. The large volumes of produced formation water contain many substances that can cause serious corrosion and scale. Also, the makeup water from other sources, subsurface or surface, complicates water handling. The paper discusses the following: corrosion and scale, oxygen, carbon dioxide, H[sub 2]S and sulfur reducing bacteria, temperature, inhibition, field tests, applications, and economics.

  6. Replacing sulfa drugs with novel DHPS inhibitors.

    PubMed

    Hammoudeh, Dalia I; Zhao, Ying; White, Stephen W; Lee, Richard E

    2013-07-01

    More research effort needs to be invested in antimicrobial drug development to address the increasing threat of multidrug-resistant organisms. The enzyme DHPS has been a validated drug target for over 70 years as the target for the highly successful sulfa drugs. The use of sulfa drugs has been compromised by the widespread presence of resistant organisms and the adverse side effects associated with their use. Despite the large amount of structural information available for DHPS, few recent publications address the possibility of using this knowledge for novel drug design. This article reviews the relevant papers and patents that report promising new small-molecule inhibitors of DHPS, and discuss these data in light of new insights into the DHPS catalytic mechanism and recently determined crystal structures of DHPS bound to potent small-molecule inhibitors. This new functional understanding confirms that DHPS deserves further consideration as an antimicrobial drug target. PMID:23859210

  7. Aurora Kinase Inhibitors: Current Status and Outlook

    PubMed Central

    Bavetsias, Vassilios; Linardopoulos, Spiros

    2015-01-01

    The Aurora kinase family comprises of cell cycle-regulated serine/threonine kinases important for mitosis. Their activity and protein expression are cell cycle regulated, peaking during mitosis to orchestrate important mitotic processes including centrosome maturation, chromosome alignment, chromosome segregation, and cytokinesis. In humans, the Aurora kinase family consists of three members; Aurora-A, Aurora-B, and Aurora-C, which each share a conserved C-terminal catalytic domain but differ in their sub-cellular localization, substrate specificity, and function during mitosis. In addition, Aurora-A and Aurora-B have been found to be overexpressed in a wide variety of human tumors. These observations led to a number of programs among academic and pharmaceutical organizations to discovering small molecule Aurora kinase inhibitors as anti-cancer drugs. This review will summarize the known Aurora kinase inhibitors currently in the clinic, and discuss the current and future directions. PMID:26734566

  8. Drug Delivery Strategies of Chemical CDK Inhibitors.

    PubMed

    Alvira, Daniel; Mondragón, Laura

    2016-01-01

    The pharmacological use of new therapeutics is often limited by a safe and effective drug-delivery system. In this sense, new chemical CDK inhibitors are not an exception. Nanotechnology may be able to solve some of the main problems limiting cancer treatments such as more specific delivery of therapeutics and reduction of toxic secondary effects. It provides new delivery systems able to specifically target cancer cells and release the active molecules in a controlled fashion. Specifically, silica mesoporous supports (SMPS) have emerged as an alternative for more classical drug delivery systems based on polymers. In this chapter, we describe the synthesis of a SMPS containing the CDK inhibitor roscovitine as cargo molecule and the protocols for confirmation of the proper cargo release of the nanoparticles in cell culture employing cell viability, cellular internalization, and cell death induction studies. PMID:26231714

  9. Secreted and transmembrane wnt inhibitors and activators.

    PubMed

    Cruciat, Cristina-Maria; Niehrs, Christof

    2013-03-01

    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. mTOR Inhibitors at a Glance

    PubMed Central

    Zheng, Yin; Jiang, Yu

    2016-01-01

    Mechanistic target of rapamycin (mTOR) is a conserved threonine and serine protein kinase that was identified more than two decades ago as the target of immunosuppressive drug rapamycin. Since then considerable amount of information has been learned about the function of this kinase. It is now well-established that mTOR plays a pivotal role in governing cell growth and proliferation, hence making mTOR a therapeutic target for disease conditions caused by deregulated cell proliferation, such as cancer. In the past decade, numerous mTOR inhibitors have been developed and many are currently in clinical trials for cancer treatment. This commentary is to provide a brief summary of these mTOR inhibitors. PMID:27134695

  11. Prospective therapeutic applications of p53 inhibitors

    SciTech Connect

    Gudkov, Andrei V. . E-mail: gudkov@ccf.org; Komarova, Elena A.

    2005-06-10

    p53, in addition to being a key cancer preventive factor, is also a determinant of cancer treatment side effects causing excessive apoptotic death in several normal tissues during cancer therapy. p53 inhibitory strategy has been suggested to protect normal tissues from chemo- and radiotherapy, and to treat other pathologies associated with stress-mediated activation of p53. This strategy was validated by isolation and testing of small molecule p53 inhibitor pifithrin-{alpha} that demonstrated broad tissue protecting capacity. However, in some normal tissues and tumors p53 plays protective role by inducing growth arrest and preventing cells from premature entrance into mitosis and death from mitotic catastrophe. Inhibition of this function of p53 can sensitize tumor cells to chemo- and radiotherapy, thus opening new potential application of p53 inhibitors and justifying the need in pharmacological agents targeting specifically either pro-apoptotic or growth arrest functions of p53.

  12. Neuroserpin, an axonally secreted serine protease inhibitor.

    PubMed Central

    Osterwalder, T; Contartese, J; Stoeckli, E T; Kuhn, T B; Sonderegger, P

    1996-01-01

    We have identified and chromatographically purified an axonally secreted glycoprotein of CNS and PNS neurons. Several peptides derived from it were microsequenced. Based on these sequences, a fragment of the corresponding cDNA was amplified and used as a probe to isolate a full length cDNA from a chicken brain cDNA library. Because the deduced amino acid sequence qualified the protein as a novel member of the serpin family of serine protease inhibitors, we called it neuroserpin. Analysis of the primary structural features further characterized neuroserpin as a heparin-independent, functional inhibitor of a trypsin-like serine protease. In situ hybridization revealed a predominantly neuronal expression during the late stages of neurogenesis and in the adult brain in regions which exhibit synaptic plasticity. Thus, neuroserpin might function as an axonally secreted regulator of the local extracellular proteolysis involved in the reorganization of the synaptic connectivity during development and synapse plasticity in the adult. Images PMID:8670795

  13. Alternative therapies for the management of inhibitors.

    PubMed

    Shima, M; Lillicrap, D; Kruse-Jarres, R

    2016-07-01

    The development of inhibitors to factor VIII (FVIII) or factor IX (FIX) remains a major treatment complication encountered in the treatment of haemophilia. Not all patients with even the same severity and genotype develop inhibitors suggesting an underlying mechanism of tolerance against FVIII- or FIX-related immunity. One mechanism may be central tolerance observed in patients in whom the FVIII mutation enables some production of the protein. The other is a peripheral tolerance mechanism which may be evident in patients with null mutation. Recently, recombinant porcine FVIII (rpFVIII, Obixur, OBI-1, BAX801) has been developed for the haemostatic treatment of both congenital haemophilia with inhibitor (CHAWI) and acquired haemophilia A (AHA). In 28 subjects with AHA with life-/limb-threatening bleeding, rpFVIII reduced or stopped bleeding in all patients within 24 h. The cross-reactivity of anti-human FVIII antibodies to rpFVIII remains around 30-50%. Recently, new therapeutics based on the quite novel concepts have been developed and clinical studies are ongoing. These are humanized asymmetric antibody mimicking FVIIIa function by maintaining a suitable interaction between FIXa and FX (Emicizumab, ACE910), and small interfering RNAs (siRNA, ALN-AT3) suppress liver production of AT through post-transcriptional gene silencing and a humanized anti-TFPI monoclonal antibody (Concizumab). Their main advantages are longer half-life, subcutaneous applicability and efficacy irrespective of the presence of inhibitors which will make it easier to initiate more effective treatment especially early childhood. PMID:27405674

  14. Trial Watch: Proteasomal inhibitors for anticancer therapy

    PubMed Central

    Obrist, Florine; Manic, Gwenola; Kroemer, Guido; Vitale, Ilio; Galluzzi, Lorenzo

    2015-01-01

    The so-called “ubiquitin-proteasome system” (UPS) is a multicomponent molecular apparatus that catalyzes the covalent attachment of several copies of the small protein ubiquitin to other proteins that are generally (but not always) destined to proteasomal degradation. This enzymatic cascade is crucial for the maintenance of intracellular protein homeostasis (both in physiological conditions and in the course of adaptive stress responses), and regulates a wide array of signaling pathways. In line with this notion, defects in the UPS have been associated with aging as well as with several pathological conditions including cardiac, neurodegenerative, and neoplastic disorders. As transformed cells often experience a constant state of stress (as a result of the hyperactivation of oncogenic signaling pathways and/or adverse microenvironmental conditions), their survival and proliferation are highly dependent on the integrity of the UPS. This rationale has driven an intense wave of preclinical and clinical investigation culminating in 2003 with the approval of the proteasomal inhibitor bortezomib by the US Food and Drug Administration for use in multiple myeloma patients. Another proteasomal inhibitor, carfilzomib, is now licensed by international regulatory agencies for use in multiple myeloma patients, and the approved indications for bortezomib have been extended to mantle cell lymphoma. This said, the clinical activity of bortezomib and carfilzomib is often limited by off-target effects, innate/acquired resistance, and the absence of validated predictive biomarkers. Moreover, the antineoplastic activity of proteasome inhibitors against solid tumors is poor. In this Trial Watch we discuss the contribution of the UPS to oncogenesis and tumor progression and summarize the design and/or results of recent clinical studies evaluating the therapeutic profile of proteasome inhibitors in cancer patients. PMID:27308423

  15. Aromatase inhibitors and anti-synthetase syndrome.

    PubMed

    Mascella, Fabio; Gianni, Lorenzo; Affatato, Alessandra; Fantini, Manuela

    2016-09-01

    Adjuvant therapy in postmenopausal women with endocrine-responsive breast cancer (BC) is actually centered on the use of anti-aromatase inhibitors (AI). Several reports, however, are emerging in literature associating the use of this drugs to rheumatic disorders. This case report describes the first case of anti-synthetase syndrome diagnosis after treatment with anti-estrogen agents in a patient with pre-existing rheumatoid arthritis. PMID:27225465

  16. Serendipity in discovery of proteasome inhibitors.

    PubMed

    Dunn, Derek; Iqbal, Mohamed; Husten, Jean; Ator, Mark A; Chatterjee, Sankar

    2012-05-15

    Among its various catalytic activities, the 'chymotrypsin-like' activity of the proteasome, a large multicatalytic proteinase complex has emerged as the focus of drug discovery efforts in cancer therapy. Herein, a series of first generation (2S, 3R)-2-amino-3-hydroxybutyric acid derived proteasome inhibitors that were discovered serendipitously en route to original goal of generating a series of sterically constrained oxazoline derivatives has been reported. PMID:22503349

  17. Inhibitors of the AAA+ Chaperone p97

    PubMed Central

    Chapman, Eli; Maksim, Nick; de la Cruz, Fabian; La Clair, James J.

    2015-01-01

    It is remarkable that a pathway as ubiquitous as protein quality control can be targeted to treat cancer. Bortezomib, an inhibitor of the proteasome, was first approved by the US Food and Drug Administration (FDA) more than 10 years ago to treat refractory myeloma and later extended to lymphoma. Its use has increased the survival rate of myeloma patients by as much as three years. This success was followed with the recent accelerated approval of the natural product derived proteasome inhibitor carfilzomib (Kyprolis®), which is used to treat patients with bortezomib-resistant multiple myeloma. The success of these two drugs has validated protein quality control as a viable target to fight select cancers, but begs the question why are proteasome inhibitors limited to lymphoma and myeloma? More recently, these limitations have encouraged the search for additional targets within the protein quality control system that might offer heightened cancer cell specificity, enhanced clinical utility, a lower rate of resistance, reduced toxicity, and mitigated side effects. One promising target is p97, an ATPase associated with various cellular activities (AAA+) chaperone. p97 figures prominently in protein quality control as well as serving a variety of other cellular functions associated with cancer. More than a decade ago, it was determined that up-regulation of p97 in many forms of cancer correlates with a poor clinical outcome. Since these initial discoveries, a mechanistic explanation for this observation has been partially illuminated, but details are lacking. Understandably, given this clinical correlation, myriad roles within the cell, and its importance in protein quality control, p97 has emerged as a potential therapeutic target. This review provides an overview of efforts towards the discovery of small molecule inhibitors of p97, offering a synopsis of efforts that parallel the excellent reviews that currently exist on p97 structure, function, and physiology. PMID

  18. Trial Watch: Proteasomal inhibitors for anticancer therapy.

    PubMed

    Obrist, Florine; Manic, Gwenola; Kroemer, Guido; Vitale, Ilio; Galluzzi, Lorenzo

    2015-01-01

    The so-called "ubiquitin-proteasome system" (UPS) is a multicomponent molecular apparatus that catalyzes the covalent attachment of several copies of the small protein ubiquitin to other proteins that are generally (but not always) destined to proteasomal degradation. This enzymatic cascade is crucial for the maintenance of intracellular protein homeostasis (both in physiological conditions and in the course of adaptive stress responses), and regulates a wide array of signaling pathways. In line with this notion, defects in the UPS have been associated with aging as well as with several pathological conditions including cardiac, neurodegenerative, and neoplastic disorders. As transformed cells often experience a constant state of stress (as a result of the hyperactivation of oncogenic signaling pathways and/or adverse microenvironmental conditions), their survival and proliferation are highly dependent on the integrity of the UPS. This rationale has driven an intense wave of preclinical and clinical investigation culminating in 2003 with the approval of the proteasomal inhibitor bortezomib by the US Food and Drug Administration for use in multiple myeloma patients. Another proteasomal inhibitor, carfilzomib, is now licensed by international regulatory agencies for use in multiple myeloma patients, and the approved indications for bortezomib have been extended to mantle cell lymphoma. This said, the clinical activity of bortezomib and carfilzomib is often limited by off-target effects, innate/acquired resistance, and the absence of validated predictive biomarkers. Moreover, the antineoplastic activity of proteasome inhibitors against solid tumors is poor. In this Trial Watch we discuss the contribution of the UPS to oncogenesis and tumor progression and summarize the design and/or results of recent clinical studies evaluating the therapeutic profile of proteasome inhibitors in cancer patients. PMID:27308423

  19. Corrosion Inhibitors as Penetrant Dyes for Radiography

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.

    2003-01-01

    Liquid/vapor-phase corrosion inhibitors (LVCIs) have been found to be additionally useful as penetrant dyes for neutron radiography (and perhaps also x-radiography). Enhancement of radiographic contrasts by use of LVCIs can reveal cracks, corrosion, and other defects that may be undetectable by ultrasonic inspection, that are hidden from direct optical inspection, and/or that are difficult or impossible to detect in radiographs made without dyes.

  20. Rust Inhibitor And Fungicide For Cooling Systems

    NASA Technical Reports Server (NTRS)

    Adams, James F.; Greer, D. Clay

    1988-01-01

    Mixture of benzotriazole, benzoic acid, and fungicide prevents growth of rust and fungus. Water-based cooling mixture made from readily available materials prevents formation of metallic oxides and growth of fungi in metallic pipes. Coolant remains clear and does not develop thick sludge tending to collect in low points in cooling systems with many commercial rust inhibitors. Coolant compatible with iron, copper, aluminum, and stainless steel. Cannot be used with cadmium or cadmium-plated pipes.

  1. Corrosion protection with eco-friendly inhibitors

    NASA Astrophysics Data System (ADS)

    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.

  2. Fluorinated dissolution inhibitors for 157-nm lithography

    NASA Astrophysics Data System (ADS)

    Hamad, Alyssandrea H.; Bae, Young C.; Liu, Xiang-Qian; Ober, Christopher K.; Houlihan, Francis M.; Dabbagh, Gary; Novembre, Anthony E.

    2002-07-01

    Fluorinated dissolution inhibitors (DIs) for 157 nm lithography were designed and synthesized as part of an ongoing study on the structure/property relationships of photoresist additives. The problem of volatilization of small DI candidates was observed from matrices such as poly(methyl methacrylate) (PMMA) and poly(hexafluorohydroxy-isopropyl styrene) (PHFHIPS) during post-apply bake cycles using Fourier Transform Infrared Spectroscopy (FT-IR). To avoid this problem, low volatility fluorinated inhibitors were designed and synthesized. Three fluorinated DIs, perfluorosuberic acid bis-(2,2,2,-trifluoro-1-phenyl-1-trifluoromethyl-ethyl) ester (PFSE1), perfluorosuberic acid bis-[1-(4-trifluoromethyl-phenyl)-ethyl] ester (PFSE2) and a fluorinated phenylmethanediol diester (FPMD1), largely remained in a PHFHIPS film during the post-apply bake. The dissolution behavior of the two fluorinated diesters was studied and found to slow down the dissolution rate of PHFHIPS with inhibition factors of 1.9 and 1.6, respectively. The absorbance of PHFHIPS films containing 10 wt% of the diester inhibitors is 3.6 AU/micron compared with an absorbance of 3.3 AU/micron for the polymer itself. The absorbance of 10% FPMD1 in PHFHIPS was measured as 3.5 AU/micron compared with an absorbance of 3.4 AU/micron for the polymer itself. Thus, the non-volatility and transparency of the fluorinated inhibitors at 157 nm as well as their ability to reduce the development rate of fluorinated polymers make them suitable for use in a 157 nm resist system.

  3. Effect of variables on downhole corrosion inhibitor application

    SciTech Connect

    Dougherty, J.A.

    1996-08-01

    One inhibitor was studied in detail to determine the effect of solvent, temperature, concentration and contact time on inhibitor application. The laboratory corrosion tests used the rotating cylinder electrode and linear polarization to measure the corrosion rate. The corrosion rate was also verified by iron loss measurements. Inhibitor was extracted from the electrode surface and the quantity determined by gas liquid chromatography. The inhibitor was also detected on the surface of the electrode by Fourier Transform Infrared spectroscopy. Corrosion rate data monitored in the field and inhibitor residue on field coupons confirm the laboratory test data.

  4. TGF-beta inhibitors for the treatment of cancer.

    PubMed

    Lahn, Michael; Kloeker, Susanne; Berry, Brandi S

    2005-06-01

    Advances in understanding the role of transforming growth factor (TGF)-beta in tumorigenesis have led to the development of TGF-beta inhibitors for cancer treatment. Three platforms of TGF-beta inhibitors have evolved: antisense oligonucleotides, monoclonal antibodies and small molecules. In this review, the current stage of development of each known TGF-beta inhibitor will be discussed. As part of the risk/benefit assessment of TGF-beta inhibitors, the known effects of TGF-beta deficiency in mice, non-clinical toxicology studies with TGF-beta inhibitors in rats, and the clinical studies with monoclonal antibodies against TGF-beta will be summarised. PMID:16004592

  5. Structure-Based Search for New Inhibitors of Cholinesterases

    PubMed Central

    Bajda, Marek; Więckowska, Anna; Hebda, Michalina; Guzior, Natalia; Sotriffer, Christoph A.; Malawska, Barbara

    2013-01-01

    Cholinesterases are important biological targets responsible for regulation of cholinergic transmission, and their inhibitors are used for the treatment of Alzheimer’s disease. To design new cholinesterase inhibitors, of different structure-based design strategies was followed, including the modification of compounds from a previously developed library and a fragment-based design approach. This led to the selection of heterodimeric structures as potential inhibitors. Synthesis and biological evaluation of selected candidates confirmed that the designed compounds were acetylcholinesterase inhibitors with IC50 values in the mid-nanomolar to low micromolar range, and some of them were also butyrylcholinesterase inhibitors. PMID:23478436

  6. Optogenetic Inhibitor of the Transcription Factor CREB.

    PubMed

    Ali, Ahmed M; Reis, Jakeb M; Xia, Yan; Rashid, Asim J; Mercaldo, Valentina; Walters, Brandon J; Brechun, Katherine E; Borisenko, Vitali; Josselyn, Sheena A; Karanicolas, John; Woolley, G Andrew

    2015-11-19

    Current approaches for optogenetic control of transcription do not mimic the activity of endogenous transcription factors, which act at numerous sites in the genome in a complex interplay with other factors. Optogenetic control of dominant negative versions of endogenous transcription factors provides a mechanism for mimicking the natural regulation of gene expression. Here we describe opto-DN-CREB, a blue-light-controlled inhibitor of the transcription factor CREB created by fusing the dominant negative inhibitor A-CREB to photoactive yellow protein (PYP). A light-driven conformational change in PYP prevents coiled-coil formation between A-CREB and CREB, thereby activating CREB. Optogenetic control of CREB function was characterized in vitro, in HEK293T cells, and in neurons where blue light enabled control of expression of the CREB targets NR4A2 and c-Fos. Dominant negative inhibitors exist for numerous transcription factors; linking these to optogenetic domains offers a general approach for spatiotemporal control of native transcriptional events. PMID:26590638

  7. Histone deacetylase inhibitors as cancer therapeutics.

    PubMed

    Clawson, Gary A

    2016-08-01

    Cancer cells contain significant alterations in their epigenomic landscape, which several enzyme families reversibly contribute to. One class of epigenetic modifying enzymes is that of histone deacetylases (HDAC), which are receiving considerable scrutiny clinically as a therapeutic target in many cancers. The underlying rationale is that inhibiting HDACs will reverse dysregulated target gene expression by modulating functional histone (or other) acetylation marks. This perspective will discuss a recent paper by Markozashvili and co-workers which appeared in Gene, which indicates that the mechanisms by which HDAC inhibitors (HDACis) alter the epigenetic landscape include widespread alternative effects beyond simply controlling regional epigenetic marks. HDACs are involved in many processes/diseases, and it is not surprising that HDACis have considerable off-target effects, and thus a major effort is being directed toward identification of inhibitors which are selective for HDAC isoforms often uniquely implicated in various cancers. This Perspective will also discuss some representative work with inhibitors targeting individual HDAC classes or isoforms. At present, it is not really clear that isoform-specific HDACis will avoid non-selective effects on other unrecognized activities of HDACs. PMID:27568481

  8. CYP17 inhibitors for prostate cancer therapy.

    PubMed

    Vasaitis, Tadas S; Bruno, Robert D; Njar, Vincent C O

    2011-05-01

    Prostate cancer (PC) is now the second most prevalent cause of death in men in the USA and Europe. At present, the major treatment options include surgical or medical castration. These strategies cause ablation of the production of testosterone (T), dihydrotestosterone (DHT) and related androgens by the testes. However, because these procedures do not affect adrenal, prostate and other tissues' androgen production, they are often combined with androgen receptor antagonists to block their action. Indeed, recent studies have unequivocally established that in castration-resistant prostate cancer (CRPC) many androgen-regulated genes become re-expressed and tissue androgen levels increase despite low serum levels. Clearly, inhibition of the key enzyme which catalyzes the biosynthesis of androgens from pregnane precursors, 17α-hydroxy/17,20-lyase (hereafter referred to as CYP17) could prevent androgen production from all sources. Thus, total ablation of androgen production by potent CYP17 inhibitors may provide effective treatment of prostate cancer patients. This review highlights the role of androgen biosynthesis in the progression of prostate cancer and the impact of CYP17 inhibitors, such as ketoconazole, abiraterone acetate, VN/124-1 (TOK-001) and TAK-700 in the clinic and in clinical development. Article from the special issue on Targeted Inhibitors. PMID:21092758

  9. Immune checkpoint inhibitors: therapeutic advances in melanoma

    PubMed Central

    Márquez-Rodas, Ivan; Cerezuela, Pablo; Soria, Ainara; Berrocal, Alfonso; Riso, Aldo; Martín-Algarra, Salvador

    2015-01-01

    In recent years, new strategies for treating melanoma have been introduced, improving the outlook for this challenging disease. One of the most important advances has been the development of immunotherapy. The better understanding of the role of the immunological system in tumor control has paved the way for strategies to enhance the immune response against cancer cells. Monoclonal antibodies (mAbs) against the immune checkpoints cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed cell death protein 1 (PD-1) and its ligand (PD-L1) have demonstrated high activity in melanoma and other tumors. Ipilimumab, an anti CTLA-4 antibody, was the first drug of this class that was approved. Although the response rate with ipilimumab is low (less than 20% of patients have objective responses), 20% of patients have long survival, with similar results in the first and second line settings. Nivolumab and pembrolizumab, both anti PD-1 inhibitors, have been approved for the treatment of melanoma, with response rates of 40% and a demonstrated survival advantage in phase III trials. This has marked a new era in the treatment of metastatic melanoma and much research is now ongoing with other drugs targeting checkpoint inhibitors. In addition, the agonist of activating molecules on T cells and their combinations are being investigated. Herein we review the clinical development of checkpoint inhibitors and their approval for treatment of metastatic melanoma. PMID:26605313

  10. Histone deacetylase inhibitors as cancer therapeutics

    PubMed Central

    2016-01-01

    Cancer cells contain significant alterations in their epigenomic landscape, which several enzyme families reversibly contribute to. One class of epigenetic modifying enzymes is that of histone deacetylases (HDAC), which are receiving considerable scrutiny clinically as a therapeutic target in many cancers. The underlying rationale is that inhibiting HDACs will reverse dysregulated target gene expression by modulating functional histone (or other) acetylation marks. This perspective will discuss a recent paper by Markozashvili and co-workers which appeared in Gene, which indicates that the mechanisms by which HDAC inhibitors (HDACis) alter the epigenetic landscape include widespread alternative effects beyond simply controlling regional epigenetic marks. HDACs are involved in many processes/diseases, and it is not surprising that HDACis have considerable off-target effects, and thus a major effort is being directed toward identification of inhibitors which are selective for HDAC isoforms often uniquely implicated in various cancers. This Perspective will also discuss some representative work with inhibitors targeting individual HDAC classes or isoforms. At present, it is not really clear that isoform-specific HDACis will avoid non-selective effects on other unrecognized activities of HDACs. PMID:27568481

  11. The hunt for HIV-1 integrase inhibitors.

    PubMed

    Lataillade, Max; Kozal, Michael J

    2006-07-01

    Currently, there are three distinct mechanistic classes of antiretrovirals: inhibitors of the HIV- 1 reverse transcriptase and protease enzymes and inhibitors of HIV entry, including receptor and coreceptor binding and cell fusion. A new drug class that inhibits the HIV-1 integrase enzyme (IN) is in development and may soon be available in the clinic. IN is an attractive drug target because it is essential for a stable and productive HIV-1 infection and there is no mammalian homologue of IN. Inhibitors of integrase enzyme (INI) block the integration of viral double-stranded DNA into the host cell's chromosomal DNA. HIV-1 integration has many potential steps that can be inhibited and several new compounds that target specific integration steps have been identified by drug developers. Recently, two INIs, GS-9137 and MK-0518, demonstrated promising early clinical trial results and have been advanced into later stage trials. In this review, we describe how IN facilitates HIV-1 integration, the needed enzyme cofactors, and the resultant byproducts created during integration. Furthermore, we review the different INIs under development, their mechanism of actions, site of IN inhibition, potency, resistance patterns, and discuss the early clinical trial results. PMID:16839248

  12. Dual Inhibitors Against Topoisomerases and Histone Deacetylases

    PubMed Central

    Seo, Young Ho

    2015-01-01

    Topoisomerases and histone deacetylases (HDACs) are considered as important therapeutic targets for a wide range of cancers, due to their association with the initiation, proliferation and survival of cancer cells. Topoisomerases are involved in the cleavage and religation processes of DNA, while HDACs regulate a dynamic epigenetic modification of the lysine amino acid on various proteins. Extensive studies have been undertaken to discover small molecule inhibitor of each protein and thereby, several drugs have been transpired from this effort and successfully approved for clinical use. However, the inherent heterogeneity and multiple genetic abnormalities of cancers challenge the clinical application of these single targeted drugs. In order to overcome the limitations of a single target approach, a novel approach, simultaneously targeting topoisomerases and HDACs with a single molecule has been recently employed and attracted much attention of medicinal chemists in drug discovery. This review highlights the current studies on the discovery of dual inhibitors against topoisomerases and HDACs, provides their pharmacological aspects and advantages, and discusses the challenges and promise of the dual inhibitors. PMID:26151040

  13. Selective Water-Soluble Gelatinase Inhibitor Prodrugs

    PubMed Central

    Gooyit, Major; Lee, Mijoon; Schroeder, Valerie A.; Ikejiri, Masahiro; Suckow, Mark A.; Mobashery, Shahriar; Chang, Mayland

    2011-01-01

    SB-3CT (1), a selective and potent thiirane-based gelatinase inhibitor, is effective in animal models of cancer metastasis and stroke; however, it is limited by poor aqueous solubility and extensive metabolism. We addressed these issues by blocking the primary site of metabolism and capitalizing on a prodrug strategy to achieve >5000-fold increased solubility. The amide prodrugs were quantitatively hydrolyzed in human blood to a potent gelatinase inhibitor, ND-322 (3). The arginyl amide prodrug (ND-478, 5d) was metabolically stable in mouse, rat, and human liver microsomes. Both 5d and 3 were non-mutagenic in the Ames II mutagenicity assay. The prodrug 5d showed moderate clearance of 0.0582 L/min/kg, remained mostly in the extracellular fluid compartment (Vd = 0.0978 L/kg), and had a terminal half-life of >4 h. The prodrug 5d had superior pharmacokinetic properties than 3, making the thiirane class of selective gelatinase inhibitors suitable for intravenous administration in treatment of acute gelatinase-dependent diseases. PMID:21866961

  14. Cinnoline derivatives as human neutrophil elastase inhibitors.

    PubMed

    Giovannoni, Maria Paola; Schepetkin, Igor A; Crocetti, Letizia; Ciciani, Giovanna; Cilibrizzi, Agostino; Guerrini, Gabriella; Khlebnikov, Andrei I; Quinn, Mark T; Vergelli, Claudia

    2016-08-01

    Compounds that can effectively inhibit the proteolytic activity of human neutrophil elastase (HNE) represent promising therapeutics for treatment of inflammatory diseases. We present here the synthesis, structure-activity relationship analysis, and biological evaluation of a new series of HNE inhibitors with a cinnoline scaffold. These compounds exhibited HNE inhibitory activity but had lower potency compared to N-benzoylindazoles previously reported by us. On the other hand, they exhibited increased stability in aqueous solution. The most potent compound, 18a, had a good balance between HNE inhibitory activity (IC50 value = 56 nM) and chemical stability (t1/2 = 114 min). Analysis of reaction kinetics revealed that these cinnoline derivatives were reversible competitive inhibitors of HNE. Furthermore, molecular docking studies of the active products into the HNE binding site revealed two types of HNE inhibitors: molecules with cinnolin-4(1H)-one scaffold, which were attacked by the HNE Ser195 hydroxyl group at the amido moiety, and cinnoline derivatives containing an ester function at C-4, which is the point of attack of Ser195. PMID:26194018

  15. Janus kinase inhibitors for rheumatoid arthritis.

    PubMed

    Yamaoka, Kunihiro

    2016-06-01

    Treatment of autoimmune diseases, such as rheumatoid arthritis (RA), has advanced substantially over the past decade with the development of biologics targeting inflammatory cytokines. Recent progress in treating RA has been achieved with janus kinase (JAK) inhibitors (Jakinibs), an orally available disease-modifying anti-rheumatic drug targeting the intracellular kinase JAK and with similar efficacy to biologics. The first Jakinib approved for RA was tofacitinib, which exerted superiority to methotrexate and non-inferiority to tumor necrosis factor (TNF) inhibitors. In recent years, the Jakinib baricitinib has demonstrated superiority to both methotrexate and a TNF inhibitor, adalimumab. Given these promising findings, Jakinibs are expected to represent the next generation compounds for treating RA, and a number of Jakinibs are currently in clinical trials. Jakinibs can differ substantially in their selectivity against JAKs; tofacitinib and baricitinib target multiple JAKs, whereas the most recently developed Jakinibs target only a single JAK. The influence of Jakinib selectivity on efficacy and side effects is of great interest, requiring further careful observation. PMID:26994322

  16. Immune Checkpoint Inhibitors in Older Adults.

    PubMed

    Elias, Rawad; Morales, Joshua; Rehman, Yasser; Khurshid, Humera

    2016-08-01

    Cancer is primarily a disease of older adults. The treatment of advanced stage tumors usually involves the use of systemic agents that may be associated with significant risk of toxicity, especially in older patients. Immune checkpoint inhibitors are newcomers to the oncology world with improved efficacy and better safety profiles when compared to traditional cytotoxic drugs. This makes them an attractive treatment option. While there are no elderly specific trials, this review attempts to look at the current available data from a geriatric oncology perspective. We reviewed data from phase III studies that led to newly approved indications of checkpoint inhibitors in non-small cell lung cancer, melanoma, and renal cell cancer. Data were reviewed with respect to response, survival, and toxicity according to three groups: <65 years, 65-75 years, and >75 years. Current literature does not allow one to draw definitive conclusions regarding the role of immune checkpoint inhibitors in older adults. However, they may offer a potentially less toxic but equally efficacious treatment option for the senior adult oncology patient. PMID:27287329

  17. Functional Analysis of Hsp70 Inhibitors

    PubMed Central

    Dahmen, Heike; Wegener, Ansgar; Sirrenberg, Christian; Musil, Djordje; Bomke, Joerg; Eggenweiler, Hans-Michael; Mayer, Matthias P.; Bukau, Bernd

    2013-01-01

    The molecular chaperones of the Hsp70 family have been recognized as targets for anti-cancer therapy. Since several paralogs of Hsp70 proteins exist in cytosol, endoplasmic reticulum and mitochondria, we investigated which isoform needs to be down-regulated for reducing viability of cancer cells. For two recently identified small molecule inhibitors, VER-155008 and 2-phenylethynesulfonamide (PES), which are proposed to target different sites in Hsp70s, we analyzed the molecular mode of action in vitro. We found that for significant reduction of viability of cancer cells simultaneous knockdown of heat-inducible Hsp70 (HSPA1) and constitutive Hsc70 (HSPA8) is necessary. The compound VER-155008, which binds to the nucleotide binding site of Hsp70, arrests the nucleotide binding domain (NBD) in a half-open conformation and thereby acts as ATP-competitive inhibitor that prevents allosteric control between NBD and substrate binding domain (SBD). Compound PES interacts with the SBD of Hsp70 in an unspecific, detergent-like fashion, under the conditions tested. None of the two inhibitors investigated was isoform-specific. PMID:24265689

  18. Sulfated chitooligosaccharides as prolyl endopeptidase inhibitor.

    PubMed

    Je, Jae-Young; Kim, Eun-Kyung; Ahn, Chang-Bum; Moon, Sang-Ho; Jeon, Byong-Tae; Kim, Bokyung; Park, Tae-Kyu; Park, Pyo-Jam

    2007-12-01

    Prolyl endopeptidase (PEP, EC 3.4.21.26) is a proline-specific endopeptidase with a serine-type mechanism, which digests small peptide-like hormones, neuroactive peptides, and various cellular factors. PEP has been involved in neurodegenerative disorders, therefore, the discovery of PEP inhibitors can revert memory loss caused by amnesic compounds. In this study, we prepared hetero-chitooligosaccharides (COSs) with different molecular sizes using ultrafiltration (UF) membrane reactor system from hetero-chitosan with different degrees of deacetylation (DD; 90%, 75% and 50% deacetylation), and synthesized sulfated COSs (SCOSs). PEP inhibitory activities of SCOSs were evaluated and the results showed that 50% deacetylated SCOSs (50-SCOSs) exhibited higher inhibitory activities than those of 90% and 75% deacetylated SCOSs (90-SCOSs and 75-SCOSs). Among the 50-SCOSs (50-SCOS I, 5000-10,000Da; 50-SCOS II, 1000-5000Da; 50-SCOS III, below 1000Da), 50-SCOS II possessed the highest inhibitory activity and IC(50) value was 0.38mg/ml. Kinetics studies with 50-SCOS II indicated a competitive enzyme inhibition with a K(i) value of 0.78mg/ml. It was concluded that the 50-SCOS II may be useful for PEP inhibitor and for developing a new type PEP inhibitor from carbohydrate based materials. PMID:17714777

  19. Effect of treatment method on corrosion inhibitor performance

    SciTech Connect

    Dougherty, J.A.

    1997-12-01

    Two types of corrosion inhibitors are studied in laboratory tests simulating batch and continuous treatment methods. Type 1 is an inhibitor which is adsorbed on the corrosion product layer and forms an inhibitor film. Type 2 reacts with the corrosion product layer to form a protective film. With both inhibitors, the protection offered by continuous treatment at 100 to 1,000 ppm inhibitor compared favorably with batch treatment using neat or 10% solutions of inhibitor. The results show batch treatment of gas phase and liquid phase coupons with a 50% solution of Type 1 inhibitor gives optimum protection. The treatment gave 91% protection on the liquid phase coupons and only 70% protection on the gas phase coupons, indicating the gas phase coupons are more difficult to inhibit. Batch treatment with neat Type 2 inhibitor gave better protection than treatment with 10% solutions of the inhibitor in methanol, crude oil or resid oil. The Type 2 inhibitor at 100 ppm in a continuous application gave as much protection as batch treatment with neat or 10% solutions of the inhibitor in solvents.

  20. Solution structures of stromelysin complexed to thiadiazole inhibitors.

    PubMed Central

    Stockman, B. J.; Waldon, D. J.; Gates, J. A.; Scahill, T. A.; Kloosterman, D. A.; Mizsak, S. A.; Jacobsen, E. J.; Belonga, K. L.; Mitchell, M. A.; Mao, B.; Petke, J. D.; Goodman, L.; Powers, E. A.; Ledbetter, S. R.; Kaytes, P. S.; Vogeli, G.; Marshall, V. P.; Petzold, G. L.; Poorman, R. A.

    1998-01-01

    Unregulated or overexpressed matrix metalloproteinases (MMPs), including stromelysin, collagenase, and gelatinase. have been implicated in several pathological conditions including arthritis and cancer. Small-molecule MMP inhibitors may have therapeutic value in the treatment of these diseases. In this regard, the solution structures of two stromelysin/ inhibitor complexes have been investigated using 1H, 13C, and 15N NMR spectroscopy. Both-inhibitors are members of a novel class of matrix metalloproteinase inhibitor that contain a thiadiazole group and that interact with stromelysin in a manner distinct from other classes of inhibitors. The inhibitors coordinate the catalytic zinc atom through their exocyclic sulfur atom, with the remainder of the ligand extending into the S1-S3 side of the active site. The binding of inhibitor containing a protonated or fluorinated aromatic ring was investigated using 1H and 19F NMR spectroscopy. The fluorinated ring was found to have a reduced ring-flip rate compared to the protonated version. A strong, coplanar interaction between the fluorinated ring of the inhibitor and the aromatic ring of Tyr155 is proposed to account for the reduced ring-flip rate and for the increase in binding affinity observed for the fluorinated inhibitor compared to the protonated inhibitor. Binding interactions observed for the thiadiazole class of ligands have implications for the design of matrix metalloproteinase inhibitors. PMID:9827994

  1. Molecular mechanism of respiratory syncytial virus fusion inhibitors

    PubMed Central

    Battles, Michael B; Langedijk, Johannes P; Furmanova-Hollenstein, Polina; Chaiwatpongsakorn, Supranee; Costello, Heather M; Kwanten, Leen; Vranckx, Luc; Vink, Paul; Jaensch, Steffen; Jonckers, Tim H M; Koul, Anil; Arnoult, Eric; Peeples, Mark E; Roymans, Dirk; McLellan, Jason S

    2016-01-01

    Respiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in young children and the elderly. Therapeutic small molecules have been developed that bind the RSV F glycoprotein and inhibit membrane fusion, yet their binding sites and molecular mechanisms of action remain largely unknown. Here we show that these inhibitors bind to a three-fold-symmetric pocket within the central cavity of the metastable prefusion conformation of RSV F. Inhibitor binding stabilizes this conformation by tethering two regions that must undergo a structural rearrangement to facilitate membrane fusion. Inhibitor-escape mutations occur in residues that directly contact the inhibitors or are involved in the conformational rearrangements required to accommodate inhibitor binding. Resistant viruses do not propagate as well as wild-type RSV in vitro, indicating a fitness cost for inhibitor escape. Collectively, these findings provide new insight into class I viral fusion proteins and should facilitate development of optimal RSV fusion inhibitors. PMID:26641933

  2. Molecular mechanism of respiratory syncytial virus fusion inhibitors.

    PubMed

    Battles, Michael B; Langedijk, Johannes P; Furmanova-Hollenstein, Polina; Chaiwatpongsakorn, Supranee; Costello, Heather M; Kwanten, Leen; Vranckx, Luc; Vink, Paul; Jaensch, Steffen; Jonckers, Tim H M; Koul, Anil; Arnoult, Eric; Peeples, Mark E; Roymans, Dirk; McLellan, Jason S

    2016-02-01

    Respiratory syncytial virus (RSV) is a leading cause of pneumonia and bronchiolitis in young children and the elderly. Therapeutic small molecules have been developed that bind the RSV F glycoprotein and inhibit membrane fusion, yet their binding sites and molecular mechanisms of action remain largely unknown. Here we show that these inhibitors bind to a three-fold-symmetric pocket within the central cavity of the metastable prefusion conformation of RSV F. Inhibitor binding stabilizes this conformation by tethering two regions that must undergo a structural rearrangement to facilitate membrane fusion. Inhibitor-escape mutations occur in residues that directly contact the inhibitors or are involved in the conformational rearrangements required to accommodate inhibitor binding. Resistant viruses do not propagate as well as wild-type RSV in vitro, indicating a fitness cost for inhibitor escape. Collectively, these findings provide new insight into class I viral fusion proteins and should facilitate development of optimal RSV fusion inhibitors. PMID:26641933

  3. Evaluation of Encapsulated Inhibitor for Autonomous Corrosion Protection

    NASA Technical Reports Server (NTRS)

    Johnsey, M. N.; Li, W.; Buhrow, J. W.; Calle, L. M.; Pearman, B. P.; Zhang, X.

    2015-01-01

    This work concerns the development of smart coating technologies based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of corrosion inhibitors into coating which provides protection through corrosion-controlled release of these inhibitors.One critical aspect of a corrosion protective smart coating is the selection of corrosion inhibitor for encapsulation and comparison of the inhibitor function before and after encapsulation. For this purpose, a systematic approach is being used to evaluate free and encapsulated corrosion inhibitors by salt immersion. Visual, optical microscope, and Scanning Electron Microscope (with low-angle backscatter electron detector) are used to evaluate these inhibitors. It has been found that the combination of different characterization tools provide an effective method for evaluation of early stage localized corrosion and the effectiveness of corrosion inhibitors.

  4. Sirtuins are Unaffected by PARP Inhibitors Containing Planar Nicotinamide Bioisosteres.

    PubMed

    Ekblad, Torun; Schüler, Herwig

    2016-03-01

    PARP-family ADP-ribosyltransferases (PARPs) and sirtuin deacetylases all use NAD(+) as cosubstrate for ADP-ribosyl transfer. PARP inhibitors are important research tools and several are being evaluated in cancer treatment. With the exception of a few tankyrase inhibitors, all current PARP inhibitors mimic the nicotinamide moiety in NAD(+) and block the nicotinamide binding pocket. We report here that while the activities of the four human sirtuin isoforms SIRT1, SIRT2, SIRT3 and SIRT6 are blocked by sirtuin inhibitor Ex527 in vitro, they are unaffected by the seven clinical and commonly used PARP inhibitors niraparib, olaparib, rucaparib, talazoparib, veliparib, PJ34, and XAV939. These findings indicate that PARP inhibitors containing planar nicotinamide mimetics do not bind to sirtuin cofactor sites. In conclusion, a simple commercially available assay can be used to rule out interference of novel PARP inhibitors with sirtuin NAD(+) binding. PMID:26518726

  5. Sulfatase inhibitors for recidivist breast cancer treatment: A chemical review.

    PubMed

    Shah, Ramanpreet; Singh, Jatinder; Singh, Dhandeep; Jaggi, Amteshwar Singh; Singh, Nirmal

    2016-05-23

    Steroid sulfatase (STS) plays a momentous role in the conversion of sulfated steroids, which are biologically inactive, into biologically active un-sulfated steroid hormones, which support the development and growth of a number of hormone-dependent cancers, including breast cancer. Therefore, inhibitors of STS are supposed to be potential drugs for the treatment of breast and other steroid-dependent cancers. The present review concentrates on broad chemical classification of steroid sulfatase inhibitors. The inhibitors reviewed are classified into four main categories: Steroid sulfamate based inhibitors; Steroid non-sulfamate based inhibitors; Non-steroidal sulfamate based inhibitors; Non-steroidal non-sulfamate based inhibitors. A succinct overview of current treatment of cancer, estradiol precursors, STS enzyme and its role in breast cancer is herein described. PMID:26974384

  6. Platelet C1- inhibitor. A secreted alpha-granule protein.

    PubMed Central

    Schmaier, A H; Smith, P M; Colman, R W

    1985-01-01

    In order to characterize which proteins of the contact phase of coagulation interact with platelets, human platelets were studied immunochemically and functionally to determine if they contain C1- inhibitor. By means of monospecific antibody to C1- inhibitor, a competitive enzyme-linked immunosorbent assay (CELISA) was developed to measure directly platelet C1- inhibitor. With the CELISA, from 33 to 115 ng of C1- inhibitor antigen per 10(8) platelets from 15 normal donors was quantified in lysates of washed human platelets solubilized in nonionic detergent. The mean concentration in 10(8) platelets was 62 +/- 33 ng (SD). Plasma C1- inhibitor either in the platelet suspension medium or on the surface of the platelets could account for only from 6.5 to 16% of the total antigen measured in the solubilized platelets. Upon functional studies, platelets contained 84 +/- 36 ng (SD) of C1- inhibitor activity in 10(8) platelets. As assessed by the CELISA, platelet C1- inhibitor antigen was immunochemically identical to plasma and purified C1- inhibitor. In contrast, the mean concentration of platelet C1- inhibitor antigen in platelets from four patients with classical hereditary angioedema was 8.3 ng/10(8) platelets (range, 5.3 to 11.3 ng/10(8) platelets). 25 and 31% of the total platelet C1- inhibitor was secreted without cell lysis from normal platelets after exposure to collagen (20 micrograms/ml) and thrombin (1 U/ml), respectively, and this secretion was blocked by metabolic inhibitors. Platelet subcellular fractionation showed that platelet C1- inhibitor resided mostly in alpha-granules, similar to the location of platelet fibrinogen. Thus, human platelets contained C1- inhibitor, which became available by platelet secretion. The identification of platelet C1- inhibitor suggests that platelets may modulate the activation of the proteins of early blood coagulation and the classical complement pathways. Images PMID:3965505

  7. Purification and characterization of elastase-specific inhibitor. Sequence homology with mucus proteinase inhibitor.

    PubMed

    Sallenave, J M; Ryle, A P

    1991-01-01

    Elastase-specific inhibitor (ESI) was purified from sputum of patients with chronic bronchitis and compared with mucus proteinase inhibitor (MPI, BrI) isolated, without the use of affinity chromatography on an enzyme, from non-purulent sputum of a patient with bronchial carcinoma. The N-terminal sequence of 27 residues of the latter was determined and showed serine as the only N-terminus. The partial N-terminal amino-acid sequence of ESI shows some homology with MPI, especially around the reactive site of MPI for human neutrophil elastase. This region could therefore be the reactive site of ESI. The thermodynamic and kinetic constants of the reactions of ESI with human neutrophil elastase and with porcine pancreatic elastase show that ESI is a fast-acting inhibitor. PMID:2039600

  8. Secretory leukoprotease inhibitor: partnering alpha 1-proteinase inhibitor to combat pulmonary inflammation.

    PubMed Central

    Bingle, L.; Tetley, T. D.

    1996-01-01

    Secretory leukoprotease inhibitor (SLPI) is a low molecular weight serine proteinase inhibitor, notably of neutrophil elastase (NE), which is synthesised and secreted by the pulmonary epithelium. SLPI plays an important role in limiting NE-induced pulmonary inflammation and, significantly, it also possesses anti-HIV activity. SLPI is a significant component of the anti-NE shield in the lung which has different reactivity from, and is therefore complementary to, the anti-NE action of alpha 1-proteinase inhibitor (alpha 1-PI). Inhaled recombinant SLPI (rSLPI) could prove beneficial in partnership with alpha 1-PI in the treatment of a number of inflammatory lung disorders including emphysema, chronic bronchitis, cystic fibrosis, and adult respiratory distress syndrome. PMID:8994529

  9. Studies on bacterial cell wall inhibitors. VI. Screening method for the specific inhibitors of peptidoglycan synthesis.

    PubMed

    Omura, S; Tanaka, H; Oiwa, R; Nagai, T; Koyama, Y; Takahashi, Y

    1979-10-01

    A screening method was established for selecting new specific inhibitors of bacterial cell wall peptidoglycan synthesis. In the primary test, culture broths of soil isolates were selected based on relative microbial activity. A culture, to be retained, must be active against Bacillus subtilis and lack activities against Acholeplasma laidawii. In the secondary test, inhibitors of bacterial cell wall synthesis were identified by their ability to prevent the incorporation of meso-[3H]diaminopimelic acid but not to prevent the incorporation of L-[4C]leucine into the acid-insoluble macromolecular fraction of growing cells of Bacillus sp. ATCC 21206 (Dpm-). As the tertiary test, inhibitors with molecular weights under 1,000 were selected by passage through a Diaflo UM-2 membrane. By this screening procedure, six known antibiotics and one new one were picked out from ten thousand soil isolates. PMID:528376

  10. Protocol for rational design of covalently interacting inhibitors.

    PubMed

    Schmidt, Thomas C; Welker, Armin; Rieger, Max; Sahu, Prabhat K; Sotriffer, Christoph A; Schirmeister, Tanja; Engels, Bernd

    2014-10-20

    The inhibition potencies of covalent inhibitors mainly result from the formation of a covalent bond to the enzyme during the inhibition mechanism. This class of inhibitors has essentially been ignored in previous target-directed drug discovery projects because of concerns about possible side effects. However, their advantages, such as higher binding energies and longer drug-target residence times moved them into the focus of recent investigations. While the rational design of non-covalent inhibitors became standard the corresponding design of covalent inhibitors is still in its early stages. Potent covalent inhibitors can be retrieved from large compound libraries by covalent docking approaches but protocols are missing that can reliably predict the influence of variations in the substitution pattern on the affinity and/or reactivity of a given covalent inhibitor. Hence, the wanted property profile can only be obtained from trial-and-error proceedings. This paper presents an appropriate protocol which is able to predict improved covalent inhibitors. It uses hybrid approaches, which mix quantum mechanical (QM) and molecular mechanical (MM) methods to predict variations in the reactivity of the inhibitor. They are also used to compute the required information about the non-covalent enzyme-inhibitor complex. Docking tools are employed to improve the inhibitor with respect to the non-covalent interactions formed in the binding site. PMID:25251382

  11. Inhibitor development in non-severe haemophilia across Europe.

    PubMed

    Fischer, Kathelijn; Iorio, Alfonso; Lassila, Riitta; Peyvandi, Flora; Calizzani, Gabriele; Gatt, Alex; Lambert, Thierry; Windyga, Jerzy; Gilman, Estelle A; Hollingsworth, R; Makris, Michael

    2015-10-01

    Evidence about inhibitor formation in non-severe haemophilia and the potential role for clotting factor concentrate type is scant. It was the aim of this study to report inhibitor development in non-severe haemophilia patients enrolled in the European Haemophilia Safety Surveillance (EUHASS) study. Inhibitors are reported quarterly and total treated patients annually. Incidence rates and 95% confidence intervals (95% CI) were calculated according to diagnosis and concentrate used. Between 1-10-2008 and 31-12-2012, 68 centres reported on 7,969 patients with non-severe haemophilia A and 1,863 patients with non-severe haemophilia B. For haemophilia A, 37 inhibitors occurred in 8,622 treatment years, resulting in an inhibitor rate of 0.43/100 treatment years (95% CI 0.30-0.59). Inhibitors occurred at a median age of 35 years, after a median of 38 exposure days (EDs; P25-P75: 20-80); with 72% occurring within the first 50 EDs. In haemophilia B, one inhibitor was detected in 2,149 treatment years, resulting in an inhibitor rate of 0.05/100 years (95% CI 0.001-0.26). This inhibitor developed at the age of six years, after six EDs. The rate of inhibitors appeared similar across recombinant and plasma derived factor VIII (FVIII) concentrates. Rates for individual concentrates could not be calculated at this stage due to low number of events. In conclusion, inhibitors in non-severe haemophilia occur three times more frequently than in previously treated patients with severe haemophilia at a rate of 0.43/100 patient years (haemophilia A) and 0.05/100 years (haemophilia B). Although the majority of inhibitors developed in the first 50 EDs, inhibitor development continued with increasing exposure to FVIII. PMID:26293381

  12. Assessing the emetic potential of PDE4 inhibitors in rats.

    PubMed

    Robichaud, A; Savoie, C; Stamatiou, P B; Lachance, N; Jolicoeur, P; Rasori, R; Chan, C C

    2002-01-01

    1. Type 4 phosphodiesterase (PDE4) inhibitors mimic the pharmacological actions of alpha(2)-adrenoceptor antagonists. This has been postulated as the mechanism by which PDE4 inhibitors induce emesis and was also demonstrated by their ability to reverse xylazine/ketamine-induced anaesthesia. We further characterized this latter effect since it appears to reflect the emetic potential of PDE4 inhibitors. 2. Selective inhibitors of PDE 1, 2, 3, 4 and 5 were studied in rats, on the duration of anaesthesia induced by the combination of xylazine (10 mg kg(-1), i.m.) and ketamine (10 mg kg(-1), i.m.). PMNPQ (i.e. 6-(4-pyridylmethyl)-8-(3-nitrophenyl)quinoline) - PDE4 inhibitor: 0.01 - 3 mg kg(-1)), like MK-912 (alpha(2)-adrenoceptor antagonist: 0.01 - 3 mg kg(-1)), dose-dependently reduced the duration of anaesthesia. In contrast, vinpocetine (PDE1 inhibitor), EHNA (PDE2 inhibitor), milrinone (PDE3 inhibitor) and zaprinast (PDE5 inhibitor) had no significant effect at the doses tested (1 - 10 mg kg(-1)). Analysis of plasma and cerebrospinal fluid (CSF) of treated animals confirmed the absorption and distribution to the brain of the inactive inhibitors. 3. Neither MK-912 (3 mg kg(-1)) nor PMNPQ (0.1 - 1 mg kg(-1)) altered the duration of anaesthesia induced via a non-alpha(2)-adrenoceptor pathway (sodium pentobarbitone 50 mg kg(-1), i.p.). 4. Central NK(1) receptors are involved in PDE4 inhibitor-induced emesis. Consistently, [sar(9), Met(O(2))(11)]-substance P (NK(1) receptor agonist, 6 microg i.c.v.) reduced the duration of anaesthesia induced by xylazine/ketamine. 5. In summary, this model is functionally coupled to PDE4, specific to alpha(2)-adrenoceptors and relevant to PDE4 inhibitor-induced emesis. It therefore provides a novel way of evaluating the emetic potential of PDE4 inhibitors in rats. PMID:11786486

  13. Guanine deaminase inhibitor from rat liver. Isolation and characterization.

    PubMed

    Ali, S; Sitaramayya, A; Kumar, K S; Krishnan, P S

    1974-01-01

    1. An inhibitor of cytoplasmic guanine deaminase of rat liver was isolated from liver ;heavy mitochondrial' fraction after freezing and thawing and treatment with Triton X-100. 2. Submitochondrial fractionation revealed that the inhibitor was localized in the outer-membrane fraction. 3. The method of purification of inhibitor, involving precipitation with (NH(4))(2)SO(4) and chromatography on DEAE-cellulose, its precipitability by trichloroacetic acid and the pattern of absorption in the u.v. indicated that the inhibitor was a protein. In confirmation, tryptic digestion of the isolated material resulted in destruction of the inhibitor activity. The inhibitor was stable to acid, but labile to heat. 4. The isolated inhibitor required phosphatidylcholine (lecithin) for activity. Phosphatidylcholine also partially protected the inhibitor against heat inactivation. 5. When detergent treatment was omitted, the inhibitor activity of frozen mitochondria was precipitated by (NH(4))(2)SO(4) in a fully active form without supplementation with phosphatidylcholine, indicating that Triton X-100 ruptured the linkage between inhibitor and lipid. 6. A reconstituted sample of inhibitor-phosphatidylcholine complex was precipitated in a fully active form by dialysis against 2-mercaptoethanol, but treatment of the precipitate with NaCl yielded an extract which was inactive unless supplemented with fresh phosphatidylcholine. 7. We interpret the results as evidence that the inhibitor was present in vivo as a lipoprotein and that once the complex was dissociated by the action of detergent and the protein precipitated, there was an absolute need for exogenous phosphatidylcholine for its activity. The manner in which inhibitor associated with the outer membrane of rat liver mitochondria might regulate the activity of the enzyme in the supernatant has been suggested. PMID:4821397

  14. Structural selectivity of human SGLT inhibitors

    PubMed Central

    Hummel, Charles S.; Lu, Chuan; Liu, Jie; Ghezzi, Chiari; Hirayama, Bruce A.; Loo, Donald D. F.; Kepe, Vladimir; Barrio, Jorge R.

    2012-01-01

    Human Na+-d-glucose cotransporter (hSGLT) inhibitors constitute the newest class of diabetes drugs, blocking up to 50% of renal glucose reabsorption in vivo. These drugs have potential for widespread use in the diabetes epidemic, but how they work at a molecular level is poorly understood. Here, we use electrophysiological methods to assess how they block Na+-d-glucose cotransporter SGLT1 and SGLT2 expressed in human embryonic kidney 293T (HEK-293T) cells and compared them to the classic SGLT inhibitor phlorizin. Dapagliflozin [(1S)-1,5,5-anhydro-1-C-{4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl}-d-glucitol], two structural analogs, and the aglycones of phlorizin and dapagliflozin were investigated in detail. Dapagliflozin and fluoro-dapagliflozin [(1S)-1,5-anhydro-1-C-{4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl}-4-F-4-deoxy-d-glucitol] blocked glucose transport and glucose-coupled currents with ≈100-fold specificity for hSGLT2 (Ki = 6 nM) over hSGLT1 (Ki = 400 nM). As galactose is a poor substrate for SGLT2, it was surprising that galacto-dapagliflozin [(1S)-1,5-anhydro-1-C-{4-chloro-3-[(4-ethoxyphenyl)methyl]phenyl}-d-galactitol] was a selective inhibitor of hSGLT2, but was less potent than dapagliflozin for both transporters (hSGLT2 Ki = 25 nM, hSGLT1 Ki = 25,000 nM). Phlorizin and galacto-dapagliflozin rapidly dissociated from SGLT2 [half-time off rate (t1/2,Off) ≈ 20–30 s], while dapagliflozin and fluoro-dapagliflozin dissociated from hSGLT2 at a rate 10-fold slower (t1/2,Off ≥ 180 s). Phlorizin was unable to exchange with dapagliflozin bound to hSGLT2. In contrast, dapagliflozin, fluoro-dapagliflozin, and galacto-dapagliflozin dissociated quickly from hSGLT1 (t1/2,Off = 1–2 s), and phlorizin readily exchanged with dapagliflozin bound to hSGLT1. The aglycones of phlorizin and dapagliflozin were poor inhibitors of both hSGLT2 and hSGLT1 with Ki values > 100 μM. These results show that inhibitor binding to SGLTs is composed of two synergistic forces

  15. Kynurenine Aminotransferase Isozyme Inhibitors: A Review

    PubMed Central

    Nematollahi, Alireza; Sun, Guanchen; Jayawickrama, Gayan S.; Church, W. Bret

    2016-01-01

    Kynurenine aminotransferase isozymes (KATs 1–4) are members of the pyridoxal-5’-phosphate (PLP)-dependent enzyme family, which catalyse the permanent conversion of l-kynurenine (l-KYN) to kynurenic acid (KYNA), a known neuroactive agent. As KATs are found in the mammalian brain and have key roles in the kynurenine pathway, involved in different categories of central nervous system (CNS) diseases, the KATs are prominent targets in the quest to treat neurodegenerative and cognitive impairment disorders. Recent studies suggest that inhibiting these enzymes would produce effects beneficial to patients with these conditions, as abnormally high levels of KYNA are observed. KAT-1 and KAT-3 share the highest sequence similarity of the isozymes in this family, and their active site pockets are also similar. Importantly, KAT-2 has the major role of kynurenic acid production (70%) in the human brain, and it is considered therefore that suitable inhibition of this isozyme would be most effective in managing major aspects of CNS diseases. Human KAT-2 inhibitors have been developed, but the most potent of them, chosen for further investigations, did not proceed in clinical studies due to the cross toxicity caused by their irreversible interaction with PLP, the required cofactor of the KAT isozymes, and any other PLP-dependent enzymes. As a consequence of the possibility of extensive undesirable adverse effects, it is also important to pursue KAT inhibitors that reversibly inhibit KATs and to include a strategy that seeks compounds likely to achieve substantial interaction with regions of the active site other than the PLP. The main purpose of this treatise is to review the recent developments with the inhibitors of KAT isozymes. This treatise also includes analyses of their crystallographic structures in complex with this enzyme family, which provides further insight for researchers in this and related studies. PMID:27314340

  16. MAO-inhibitors in Parkinson's Disease

    PubMed Central

    Laux, Gerd

    2011-01-01

    Monoamine oxidase inhibitors (MAO-I) belong to the earliest drugs tried in Parkinson's disease (PD). They have been used with or without levodopa (L-DOPA). Non-selective MAO-I due to their side-effect/adverse reaction profile, like tranylcypromine have limited use in the treatment of depression in PD, while selective, reversible MAO-A inhibitors are recommended due to their easier clinical handling. For the treatment of akinesia and motor fluctuations selective irreversible MAO-B inhibitors selegiline and rasagiline are recommended. They are safe and well tolerated at the recommended daily doses. Their main differences are related to (1) metabolism, (2) interaction with CYP-enzymes and (3) quantitative properties at the molecular biological/genetic level. Rasagiline is more potent in clinical practise and has a hypothesis driven more favourable side effect/adverse reaction profile due to its metabolism to aminoindan. Both selegiline and rasagiline have a neuroprotective and neurorestaurative potential. A head-to head clinical trial would be of utmost interest from both the clinical outcome and a hypothesis-driven point of view. Selegiline is available as tablet and melting tablet for PD and as transdermal selegiline for depression, while rasagiline is marketed as tablet for PD. In general, the clinical use of MAO-I nowadays is underestimated. There should be more efforts to evaluate their clinical potency as antidepressants and antidementive drugs in addition to the final proof of their disease-modifying potential. In line with this are recent innovative developments of MAO-I plus inhibition of acetylcholine esterase for Alzheimer's disease as well as combined MAO-I and iron chelation for PD. PMID:22110357

  17. Sifuvirtide, a potent HIV fusion inhibitor peptide

    SciTech Connect

    Wang, Rui-Rui; Yang, Liu-Meng; Wang, Yun-Hua; Pang, Wei; Tam, Siu-Cheung; Tien, Po; Zheng, Yong-Tang

    2009-05-08

    Enfuvirtide (ENF) is currently the only FDA approved HIV fusion inhibitor in clinical use. Searching for more drugs in this category with higher efficacy and lower toxicity seems to be a logical next step. In line with this objective, a synthetic peptide with 36 amino acid residues, called Sifuvirtide (SFT), was designed based on the crystal structure of gp41. In this study, we show that SFT is a potent anti-HIV agent with relatively low cytotoxicity. SFT was found to inhibit replication of all tested HIV strains. The effective concentrations that inhibited 50% viral replication (EC{sub 50}), as determined in all tested strains, were either comparable or lower than benchmark values derived from well-known anti-HIV drugs like ENF or AZT, while the cytotoxic concentrations causing 50% cell death (CC{sub 50}) were relatively high, rendering it an ideal anti-HIV agent. A GST-pull down assay was performed to confirm that SFT is a fusion inhibitor. Furthermore, the activity of SFT on other targets in the HIV life cycle was also investigated, and all assays showed negative results. To further understand the mechanism of action of HIV peptide inhibitors, resistant variants of HIV-1{sub IIIB} were derived by serial virus passage in the presence of increasing doses of SFT or ENF. The results showed that there was cross-resistance between SFT and ENF. In conclusion, SFT is an ideal anti-HIV agent with high potency and low cytotoxicity, but may exhibit a certain extent of cross-resistance with ENF.

  18. Kynurenine Aminotransferase Isozyme Inhibitors: A Review.

    PubMed

    Nematollahi, Alireza; Sun, Guanchen; Jayawickrama, Gayan S; Church, W Bret

    2016-01-01

    Kynurenine aminotransferase isozymes (KATs 1-4) are members of the pyridoxal-5'-phosphate (PLP)-dependent enzyme family, which catalyse the permanent conversion of l-kynurenine (l-KYN) to kynurenic acid (KYNA), a known neuroactive agent. As KATs are found in the mammalian brain and have key roles in the kynurenine pathway, involved in different categories of central nervous system (CNS) diseases, the KATs are prominent targets in the quest to treat neurodegenerative and cognitive impairment disorders. Recent studies suggest that inhibiting these enzymes would produce effects beneficial to patients with these conditions, as abnormally high levels of KYNA are observed. KAT-1 and KAT-3 share the highest sequence similarity of the isozymes in this family, and their active site pockets are also similar. Importantly, KAT-2 has the major role of kynurenic acid production (70%) in the human brain, and it is considered therefore that suitable inhibition of this isozyme would be most effective in managing major aspects of CNS diseases. Human KAT-2 inhibitors have been developed, but the most potent of them, chosen for further investigations, did not proceed in clinical studies due to the cross toxicity caused by their irreversible interaction with PLP, the required cofactor of the KAT isozymes, and any other PLP-dependent enzymes. As a consequence of the possibility of extensive undesirable adverse effects, it is also important to pursue KAT inhibitors that reversibly inhibit KATs and to include a strategy that seeks compounds likely to achieve substantial interaction with regions of the active site other than the PLP. The main purpose of this treatise is to review the recent developments with the inhibitors of KAT isozymes. This treatise also includes analyses of their crystallographic structures in complex with this enzyme family, which provides further insight for researchers in this and related studies. PMID:27314340

  19. Nanomolar Inhibitors of Trypanosoma brucei RNA Triphosphatase

    PubMed Central

    Smith, Paul; Ho, C. Kiong; Takagi, Yuko; Djaballah, Hakim

    2016-01-01

    ABSTRACT Eukaryal taxa differ with respect to the structure and mechanism of the RNA triphosphatase (RTPase) component of the mRNA capping apparatus. Protozoa, fungi, and certain DNA viruses have a metal-dependent RTPase that belongs to the triphosphate tunnel metalloenzyme (TTM) superfamily. Because the structures, active sites, and chemical mechanisms of the TTM-type RTPases differ from those of mammalian RTPases, the TTM RTPases are potential targets for antiprotozoal, antifungal, and antiviral drug discovery. Here, we employed RNA interference (RNAi) knockdown methods to show that Trypanosoma brucei RTPase Cet1 (TbCet1) is necessary for proliferation of procyclic cells in culture. We then conducted a high-throughput biochemical screen for small-molecule inhibitors of the phosphohydrolase activity of TbCet1. We identified several classes of chemicals—including chlorogenic acids, phenolic glycopyranosides, flavonoids, and other phenolics—that inhibit TbCet1 with nanomolar to low-micromolar 50% inhibitory concentrations (IC50s). We confirmed the activity of these compounds, and tested various analogs thereof, by direct manual assays of TbCet1 phosphohydrolase activity. The most potent nanomolar inhibitors included tetracaffeoylquinic acid, 5-galloylgalloylquinic acid, pentagalloylglucose, rosmarinic acid, and miquelianin. TbCet1 inhibitors were less active (or inactive) against the orthologous TTM-type RTPases of mimivirus, baculovirus, and budding yeast (Saccharomyces cerevisiae). Our results affirm that a TTM RTPase is subject to potent inhibition by small molecules, with the caveat that parallel screens against TTM RTPases from multiple different pathogens may be required to fully probe the chemical space of TTM inhibition. PMID:26908574

  20. Tools for Characterizing Bacterial Protein Synthesis Inhibitors

    PubMed Central

    Orelle, Cédric; Carlson, Skylar; Kaushal, Bindiya; Almutairi, Mashal M.; Liu, Haipeng; Ochabowicz, Anna; Quan, Selwyn; Pham, Van Cuong; Squires, Catherine L.; Murphy, Brian T.

    2013-01-01

    Many antibiotics inhibit the growth of sensitive bacteria by interfering with ribosome function. However, discovery of new protein synthesis inhibitors is curbed by the lack of facile techniques capable of readily identifying antibiotic target sites and modes of action. Furthermore, the frequent rediscovery of known antibiotic scaffolds, especially in natural product extracts, is time-consuming and expensive and diverts resources that could be used toward the isolation of novel lead molecules. In order to avoid these pitfalls and improve the process of dereplication of chemically complex extracts, we designed a two-pronged approach for the characterization of inhibitors of protein synthesis (ChIPS) that is suitable for the rapid identification of the site and mode of action on the bacterial ribosome. First, we engineered antibiotic-hypersensitive Escherichia coli strains that contain only one rRNA operon. These strains are used for the rapid isolation of resistance mutants in which rRNA mutations identify the site of the antibiotic action. Second, we show that patterns of drug-induced ribosome stalling on mRNA, monitored by primer extension, can be used to elucidate the mode of antibiotic action. These analyses can be performed within a few days and provide a rapid and efficient approach for identifying the site and mode of action of translation inhibitors targeting the bacterial ribosome. Both techniques were validated using a bacterial strain whose culture extract, composed of unknown metabolites, exhibited protein synthesis inhibitory activity; we were able to rapidly detect the presence of the antibiotic chloramphenicol. PMID:24041905

  1. Ability of the Met Kinase Inhibitor Crizotinib and New Generation EGFR Inhibitors to Overcome Resistance to EGFR Inhibitors

    PubMed Central

    Nanjo, Shigeki; Yamada, Tadaaki; Nishihara, Hiroshi; Takeuchi, Shinji; Sano, Takako; Nakagawa, Takayuki; Ishikawa, Daisuke; Zhao, Lu; Ebi, Hiromichi; Yasumoto, Kazuo; Matsumoto, Kunio; Yano, Seiji

    2013-01-01

    Purpose Although EGF receptor tyrosine kinase inhibitors (EGFR-TKI) have shown dramatic effects against EGFR mutant lung cancer, patients ultimately develop resistance by multiple mechanisms. We therefore assessed the ability of combined treatment with the Met inhibitor crizotinib and new generation EGFR-TKIs to overcome resistance to first-generation EGFR-TKIs. Experimental Design Lung cancer cell lines made resistant to EGFR-TKIs by the gatekeeper EGFR-T790M mutation, Met amplification, and HGF overexpression and mice with tumors induced by these cells were treated with crizotinib and a new generation EGFR-TKI. Results The new generation EGFR-TKI inhibited the growth of lung cancer cells containing the gatekeeper EGFR-T790M mutation, but did not inhibit the growth of cells with Met amplification or HGF overexpression. In contrast, combined therapy with crizotinib plus afatinib or WZ4002 was effective against all three types of cells, inhibiting EGFR and Met phosphorylation and their downstream molecules. Crizotinib combined with afatinib or WZ4002 potently inhibited the growth of mouse tumors induced by these lung cancer cell lines. However, the combination of high dose crizotinib and afatinib, but not WZ4002, triggered severe adverse events. Conclusions Our results suggest that the dual blockade of mutant EGFR and Met by crizotinib and a new generation EGFR-TKI may be promising for overcoming resistance to reversible EGFR-TKIs but careful assessment is warranted clinically. PMID:24386407

  2. Structural insights into human 5-lipoxygenase inhibition: combined ligand-based and target-based approach.

    PubMed

    Charlier, Caroline; Hénichart, Jean-Pierre; Durant, François; Wouters, Johan

    2006-01-12

    The human 5-LOX enzyme and its interaction with competitive inhibitors were investigated by means of a combined ligand-based and target-based approach. First, a pharmacophore model was generated for 16 non redox 5-LOX inhibitors with Catalyst (HipHop module). It includes two hydrophobic groups, an aromatic ring, and two hydrogen bond acceptors. The 3D structure of human 5-LOX was then modeled based on the crystal structure of rabbit 15-LOX, and the binding modes of representative ligands were studied by molecular docking. Confrontation of the docking results with the pharmacophore model allowed the weighting of the pharmacophoric features and the integration of structural information. This led to the proposal of an interaction model inside the 5-LOX active site, consisting of four major and two secondary interaction points: on one hand, two hydrophobic groups, an aromatic ring, and a hydrogen bond acceptor, and, on the other hand, an acidic moiety and an additional hydrogen bond acceptor. PMID:16392803

  3. 5-Lipoxygenase and cyclooxygenase-1 inhibitory active compounds from Atractylodes lancea.

    PubMed

    Resch, M; Steigel, A; Chen, Z L; Bauer, R

    1998-03-01

    Lipophilic extracts of Atractylodes lancea rhizomes exhibited potent inhibitory activities in 5-lipoxygenase [IC50 (5-LOX) = 2.9 micrograms/mL (n-hexane extract)] and cyclooxygenase-1 [IC50 (COX-1) = 30.5 micrograms/mL (n-hexane extract)] enzymatic assays. Bioactivity-guided fractionation of the n-hexane extract led to the isolation of a new compound atractylochromene (1), a potent inhibitor in both test systems [IC50 (5-LOX) = 0.6 microM, IC50 (COX-1) = 3.3 microM]. Also obtained was 2-[(2E)-3,7-dimethyl-2,6-octadienyl]-6-methyl-2,5-cyclohexadiene-1 ,4-dione (2), which showed a selective inhibitory activity against 5-LOX [IC50 (5-LOX) 0.2 microM, IC50 (COX-1) 64.3 microM]. The sesquiterpene atractylon (3) and the coumarin osthol (4) turned out to be moderate but selective 5-lipoxygenase inhibitors. Atractylenolides I (5), II (6), and III (7) showed no significant inhibitory effects for either enzyme. Structures were established by spectral data interpretation. PMID:9544564

  4. Dimethyl ester of bilirubin exhibits anti-inflammatory activity through inhibition of secretory phospholipase A2, lipoxygenase and cyclooxygenase.

    PubMed

    Joshi, Vikram; Umashankara, M; Ramakrishnan, Chandrasekaran; Nanjaraj Urs, Ankanahalli N; Suvilesh, Kanve Nagaraj; Velmurugan, Devadasan; Rangappa, Kanchugarakoppal S; Vishwanath, Bannikuppe Sannanaik

    2016-05-15

    Overproduction of arachidonic acid (AA) mediated by secretory phospholipase A2 group IIA (sPLA2IIA) is a hallmark of many inflammatory disorders. AA is subsequently converted into pro-inflammatory eicosanoids through 5-lipoxygenase (5-LOX) and cyclooxygenase-1/2 (COX-1/2) activities. Hence, inhibition of sPLA2IIA, 5-LOX and COX-1/2 activities is critical in regulating inflammation. We have previously reported unconjugated bilirubin (UCB), an endogenous antioxidant, as sPLA2IIA inhibitor. However, lipophilic UCB gets conjugated in liver with glucuronic acid into hydrophilic conjugated bilirubin (CB). Since hydrophobicity is pre-requisite for sPLA2IIA inhibition, conjugation reduces the efficacy of UCB. In this regard, UCB was chemically modified and derivatives were evaluated for sPLA2IIA, 5-LOX and COX-1/2 inhibition. Among the derivatives, BD1 (dimethyl ester of bilirubin) exhibited ∼ 3 fold greater inhibitory potency towards sPLA2IIA compared to UCB. Both UCB and BD1 inhibited human 5-LOX and COX-2 activities; however only BD1 inhibited AA induced platelet aggregation. Molecular docking studies demonstrated BD1 as better inhibitor of aforesaid enzymes than UCB and other endogenous antioxidants. These data suggest that BD1 exhibits strong anti-inflammatory activity through inhibition of AA cascade enzymes which is of great therapeutic importance. PMID:27060751

  5. Inhibitors of glycogen synthase 3 kinase

    DOEpatents

    Schultz, Peter; Ring, David B.; Harrison, Stephen D.; Bray, Andrew M.

    2006-05-30

    Compounds of formula 1: ##STR00001## wherein R.sub.1 is alkyl, cycloalkyl, aryl, aralkyl, heteroaryl, or heteroaralkyl, substituted with 0 3 substituents selected from lower alkyl, halo, hydroxy, lower alkoxy, amino, lower alkyl-amino, and nitro; R.sub.2 is hydroxy, amino, or lower alkoxy; R.sub.3 is H, lower alkyl, lower acyl, lower alkoxy-acyl, or amino-acyl; R.sub.4 is H or lower alkyl; and pharmaceutically acceptable salts and esters thereof; are effective inhibitors of GSK3.

  6. Bioconversion of lignocellulose: inhibitors and detoxification

    PubMed Central

    2013-01-01

    Bioconversion of lignocellulose by microbial fermentation is typically preceded by an acidic thermochemical pretreatment step designed to facilitate enzymatic hydrolysis of cellulose. Substances formed during the pretreatment of the lignocellulosic feedstock inhibit enzymatic hydrolysis as well as microbial fermentation steps. This review focuses on inhibitors from lignocellulosic feedstocks and how conditioning of slurries and hydrolysates can be used to alleviate inhibition problems. Novel developments in the area include chemical in-situ detoxification by using reducing agents, and methods that improve the performance of both enzymatic and microbial biocatalysts. PMID:23356676

  7. PDE-10A inhibitors as insulin secretagogues.

    PubMed

    Cantin, Louis-David; Magnuson, Steven; Gunn, David; Barucci, Nicole; Breuhaus, Marina; Bullock, William H; Burke, Jennifer; Claus, Thomas H; Daly, Michelle; Decarr, Lynn; Gore-Willse, Ann; Hoover-Litty, Helana; Kumarasinghe, Ellalahewage S; Li, Yaxin; Liang, Sidney X; Livingston, James N; Lowinger, Timothy; Macdougall, Margit; Ogutu, Herbert O; Olague, Alan; Ott-Morgan, Ronda; Schoenleber, Robert W; Tersteegen, Adrian; Wickens, Philip; Zhang, Zhonghua; Zhu, Jian; Zhu, Lei; Sweet, Laurel J

    2007-05-15

    Modulation of cAMP levels has been linked to insulin secretion in preclinical animal models and in humans. The high expression of PDE-10A in pancreatic islets suggested that inhibition of this enzyme may provide the necessary modulation to elicit increased insulin secretion. Using an HTS approach, we have identified quinoline-based PDE-10A inhibitors as insulin secretagogues in vitro. Optimized compounds were evaluated in vivo where improvements in glucose tolerance and increases in insulin secretion were measured. PMID:17400452

  8. Protease inhibitors targeting coronavirus and filovirus entry.

    PubMed

    Zhou, Yanchen; Vedantham, Punitha; Lu, Kai; Agudelo, Juliet; Carrion, Ricardo; Nunneley, Jerritt W; Barnard, Dale; Pöhlmann, Stefan; McKerrow, James H; Renslo, Adam R; Simmons, Graham

    2015-04-01

    In order to gain entry into cells, diverse viruses, including Ebola virus, SARS-coronavirus and the emerging MERS-coronavirus, depend on activation of their envelope glycoproteins by host cell proteases. The respective enzymes are thus excellent targets for antiviral intervention. In cell culture, activation of Ebola virus, as well as SARS- and MERS-coronavirus can be accomplished by the endosomal cysteine proteases, cathepsin L (CTSL) and cathepsin B (CTSB). In addition, SARS- and MERS-coronavirus can use serine proteases localized at the cell surface, for their activation. However, it is currently unclear which protease(s) facilitate viral spread in the infected host. We report here that the cysteine protease inhibitor K11777, ((2S)-N-[(1E,3S)-1-(benzenesulfonyl)-5-phenylpent-1-en-3-yl]-2-{[(E)-4-methylpiperazine-1-carbonyl]amino}-3-phenylpropanamide) and closely-related vinylsulfones act as broad-spectrum antivirals by targeting cathepsin-mediated cell entry. K11777 is already in advanced stages of development for a number of parasitic diseases, such as Chagas disease, and has proven to be safe and effective in a range of animal models. K11777 inhibition of SARS-CoV and Ebola virus entry was observed in the sub-nanomolar range. In order to assess whether cysteine or serine proteases promote viral spread in the host, we compared the antiviral activity of an optimized K11777-derivative with that of camostat, an inhibitor of TMPRSS2 and related serine proteases. Employing a pathogenic animal model of SARS-CoV infection, we demonstrated that viral spread and pathogenesis of SARS-CoV is driven by serine rather than cysteine proteases and can be effectively prevented by camostat. Camostat has been clinically used to treat chronic pancreatitis, and thus represents an exciting potential therapeutic for respiratory coronavirus infections. Our results indicate that camostat, or similar serine protease inhibitors, might be an effective option for treatment of SARS and

  9. Improving cancer immunotherapy with DNA methyltransferase inhibitors.

    PubMed

    Saleh, Mohammad H; Wang, Lei; Goldberg, Michael S

    2016-07-01

    Immunotherapy confers durable clinical benefit to melanoma, lung, and kidney cancer patients. Challengingly, most other solid tumors, including ovarian carcinoma, are not particularly responsive to immunotherapy, so combination with a complementary therapy may be beneficial. Recent findings suggest that epigenetic modifying drugs can prime antitumor immunity by increasing expression of tumor-associated antigens, chemokines, and activating ligands by cancer cells as well as cytokines by immune cells. This review, drawing from both preclinical and clinical data, describes some of the mechanisms of action that enable DNA methyltransferase inhibitors to facilitate the establishment of antitumor immunity. PMID:26646852

  10. Inside HDACs with more selective HDAC inhibitors.

    PubMed

    Roche, Joëlle; Bertrand, Philippe

    2016-10-01

    Inhibitors of histone deacetylases (HDACs) are nowadays part of the therapeutic arsenal mainly against cancers, with four compounds approved by the Food and Drug Administration. During the last five years, several groups have made continuous efforts to improve this class of compounds, designing more selective compounds or compounds with multiple capacities. After a survey of the HDAC biology and structures, this review summarizes the results of the chemists working in this field, and highlights when possible the behavior of the molecules inside their targets. PMID:27318122

  11. Recent Progress in Histone Demethylase Inhibitors.

    PubMed

    McAllister, Tom E; England, Katherine S; Hopkinson, Richard J; Brennan, Paul E; Kawamura, Akane; Schofield, Christopher J

    2016-02-25

    There is increasing interest in targeting histone N-methyl-lysine demethylases (KDMs) with small molecules both for the generation of probes for target exploration and for therapeutic purposes. Here we update on previous reviews on the inhibition of the lysine-specific demethylases (LSDs or KDM1s) and JmjC families of N-methyl-lysine demethylases (JmjC KDMs, KDM2-7), focusing on the academic and patent literature from 2014 to date. We also highlight recent biochemical, biological, and structural studies which are relevant to KDM inhibitor development. PMID:26710088

  12. Inhibitors of glycogen synthase 3 kinase

    DOEpatents

    Schultz, Peter; Ring, David B.; Harrison, Stephen D.; Bray, Andrew M.

    2000-01-01

    Compounds of formula 1: ##STR1## wherein R.sub.1 is alkyl, cycloalkyl, aryl, aralkyl, heteroaryl, or heteroaralkyl, substituted with 0-3 substituents selected from lower alkyl, halo, hydroxy, lower alkoxy, amino, lower alkyl-amino, and nitro; R.sub.2 is hydroxy, amino, or lower alkoxy; R.sub.3 is H, lower alkyl, lower acyl, lower alkoxy-acyl, or amnino-acyl; R.sub.4 is H or lower alkyl; and pharmaceutically acceptable salts and esters thereof; are effective inhibitors of GSK3.

  13. Chlorolissoclimides: New inhibitors of eukaryotic protein synthesis

    PubMed Central

    Robert, Francis; Gao, Hong Qing; Donia, Marwa; Merrick, William C.; Hamann, Mark T.; Pelletier, Jerry

    2006-01-01

    Lissoclimides are cytotoxic compounds produced by shell-less molluscs through chemical secretions to deter predators. Chlorinated lissoclimides were identified as the active component of a marine extract from Pleurobranchus forskalii found during a high-throughput screening campaign to characterize new protein synthesis inhibitors. It was demonstrated that these compounds inhibit protein synthesis in vitro, in extracts prepared from mammalian and plant cells, as well as in vivo against mammalian cells. Our results suggest that they block translation elongation by inhibiting translocation, leading to an accumulation of ribosomes on mRNA. These data provide a rationale for the cytotoxic nature of this class of small molecule natural products. PMID:16540697

  14. KIDFamMap: a database of kinase-inhibitor-disease family maps for kinase inhibitor selectivity and binding mechanisms.

    PubMed

    Chiu, Yi-Yuan; Lin, Chih-Ta; Huang, Jhang-Wei; Hsu, Kai-Cheng; Tseng, Jen-Hu; You, Syuan-Ren; Yang, Jinn-Moon

    2013-01-01

    Kinases play central roles in signaling pathways and are promising therapeutic targets for many diseases. Designing selective kinase inhibitors is an emergent and challenging task, because kinases share an evolutionary conserved ATP-binding site. KIDFamMap (http://gemdock.life.nctu.edu.tw/KIDFamMap/) is the first database to explore kinase-inhibitor families (KIFs) and kinase-inhibitor-disease (KID) relationships for kinase inhibitor selectivity and mechanisms. This database includes 1208 KIFs, 962 KIDs, 55 603 kinase-inhibitor interactions (KIIs), 35 788 kinase inhibitors, 399 human protein kinases, 339 diseases and 638 disease allelic variants. Here, a KIF can be defined as follows: (i) the kinases in the KIF with significant sequence similarity, (ii) the inhibitors in the KIF with significant topology similarity and (iii) the KIIs in the KIF with significant interaction similarity. The KIIs within a KIF are often conserved on some consensus KIDFamMap anchors, which represent conserved interactions between the kinase subsites and consensus moieties of their inhibitors. Our experimental results reveal that the members of a KIF often possess similar inhibition profiles. The KIDFamMap anchors can reflect kinase conformations types, kinase functions and kinase inhibitor selectivity. We believe that KIDFamMap provides biological insights into kinase inhibitor selectivity and binding mechanisms. PMID:23193279

  15. KIDFamMap: a database of kinase-inhibitor-disease family maps for kinase inhibitor selectivity and binding mechanisms

    PubMed Central

    Chiu, Yi-Yuan; Lin, Chih-Ta; Huang, Jhang-Wei; Hsu, Kai-Cheng; Tseng, Jen-Hu; You, Syuan-Ren; Yang, Jinn-Moon

    2013-01-01

    Kinases play central roles in signaling pathways and are promising therapeutic targets for many diseases. Designing selective kinase inhibitors is an emergent and challenging task, because kinases share an evolutionary conserved ATP-binding site. KIDFamMap (http://gemdock.life.nctu.edu.tw/KIDFamMap/) is the first database to explore kinase-inhibitor families (KIFs) and kinase-inhibitor-disease (KID) relationships for kinase inhibitor selectivity and mechanisms. This database includes 1208 KIFs, 962 KIDs, 55 603 kinase-inhibitor interactions (KIIs), 35 788 kinase inhibitors, 399 human protein kinases, 339 diseases and 638 disease allelic variants. Here, a KIF can be defined as follows: (i) the kinases in the KIF with significant sequence similarity, (ii) the inhibitors in the KIF with significant topology similarity and (iii) the KIIs in the KIF with significant interaction similarity. The KIIs within a KIF are often conserved on some consensus KIDFamMap anchors, which represent conserved interactions between the kinase subsites and consensus moieties of their inhibitors. Our experimental results reveal that the members of a KIF often possess similar inhibition profiles. The KIDFamMap anchors can reflect kinase conformations types, kinase functions and kinase inhibitor selectivity. We believe that KIDFamMap provides biological insights into kinase inhibitor selectivity and binding mechanisms. PMID:23193279

  16. Examination of the change in returning molecular weight obtained during inhibitor squeeze treatments using polyacrylate based inhibitors

    SciTech Connect

    Graham, G.M.; Sorbie, K.S.

    1995-11-01

    Scale inhibitors based on small polyelectrolytes are often employed in oilfield scale prevention treatments. These materials are injected into the near-well formation of producers in a scale inhibitor squeeze treatment. When the well is brought back on production, the objective is for the return concentration level of the inhibitor in the produced brine to be at or above a certain threshold level, C{sub t}. This threshold level is the minimum inhibitor concentration required to prevent the formation of mineral carbonate or sulfate scales in that well. The squeeze lifetime depends strongly on the nature of the interaction between the inhibitor and the formation either through an adsorption or precipitation mechanism. Both adsorption and precipitation processes depend on the molecular weight of the scale inhibitor, as well as on a range of other factors. However, polymeric inhibitor species always display some degree of polydispersity (spread of molecular weight). In this paper, the authors examine the effects of molecular weight on adsorption/desorption phenomena for polyacrylate based inhibitor species. This work shows that, in the inhibitor effluent after a squeeze treatment, the molecular weight of the returning inhibitor may be different from that which was injected. For commercially available polymeric inhibitor species, they demonstrate using core floods that preferential retention of higher molecular weight components occurs and preferential desorption of lower molecular weight components is observed. This leads to a gradation in molecular weight in the return profile, which can lead to increased molecular weight components returning as the inhibitor concentration approaches the threshold level. The significance of this observation to field application of polymeric inhibitor species is discussed.

  17. Recent chymase inhibitors and their effects in in vivo models.

    PubMed

    Muto, Tsuyoshi; Fukami, Harukazu

    2002-12-01

    Recent efforts to discover novel chymase inhibitors have produced orally bioavailable compounds. Studies using such inhibitors have shed light on the pathophysiological roles of chymase, eg, a chymase inhibitor has prevented atherosclerosis, restenosis and myocardial infarction in respective animal models. In these cardiovascular diseases, angiotensin I is likely involved as a substrate for chymase. The studies using chymase inhibitors have also shown the potential role of chymase in other diseases, including atopic dermatitis, tissue fibrosis and rheumatoid arthritis; a chymase inhibitor also reduced ischemic reperfusion injury in the small intestine. These results suggest the existence of physiological substrates for chymase other than angiotensin I. Chymase inhibitors are promising for the treatment of cardiovascular as well as inflammatory diseases. PMID:12800055

  18. Enzyme inhibitors in tuber crops and their thermal stability.

    PubMed

    Prathibha, S; Nambisan, B; Leelamma, S

    1995-10-01

    Tubers of Cassava (Manihot esculenta), yams (Dioscorea esculenta), aroids (Amorphophallus campanulatus, Colocasia esculenta, Xanthosoma sagittfolium) and Coleus (Solenostemon rotundifolius) were screened for inhibitory activities against amylase, trypsin and chymotrypsin. Coleus tuber possessed the highest anti-amylase activity, whereas Colocasia tuber was the most potent source of anti-tryptic and anti-chymotryptic activity. Xanthosoma tubers exhibited amylase inhibitory activity and Amorphophallus tubers antiprotease activity. Dioscorea esculenta had low levels of amylase and chymotrypsin inhibitors, while Cassava tubers were totally free of inhibitors. When tubers were processed by pressure cooking, there was significant reduction/complete elimination in inhibitory activity. Partial retention of inhibition was observed in the case of amylase inhibitor in Dioscorea, chymotrypsin inhibitor in Colocasia and trypsin inhibitor in Colocasia, Coleus and Amorphophallus. In vitro experiments on heat stability of the different inhibitors revealed almost similar pattern of inactivation. PMID:8833431

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

    PubMed Central

    Akimitsu, Nobuyoshi

    2013-01-01

    Currently, hepatitis C virus (HCV) infection is considered a serious health-care problem all over the world. A good number of direct-acting antivirals (DAAs) against HCV infection are in clinical progress including NS3-4A protease inhibitors, RNA-dependent RNA polymerase inhibitors, and NS5A inhibitors as well as host targeted inhibitors. Two NS3-4A protease inhibitors (telaprevir and boceprevir) have been recently approved for the treatment of hepatitis C in combination with standard of care (pegylated interferon plus ribavirin). The new therapy has significantly improved sustained virologic response (SVR); however, the adverse effects associated with this therapy are still the main concern. In addition to the emergence of viral resistance, other targets must be continually developed. One such underdeveloped target is the helicase portion of the HCV NS3 protein. This review article summarizes our current understanding of HCV treatment, particularly with those of NS3 inhibitors. PMID:24282816

  20. Secretory leukocyte proteinase inhibitor is a major leukocyte elastase inhibitor in human neutrophils.

    PubMed

    Sallenave, J M; Si Tahar, M; Cox, G; Chignard, M; Gauldie, J

    1997-06-01

    Secretory leukocyte proteinase inhibitor (SLPI) is the main neutrophil elastase (HLE) inhibitor found in the upper airways during pulmonary inflammation. It has been shown to be synthesized and secreted in vitro by epithelial cells and has been localized in tracheal glands and bronchiolar epithelial cells by immunocytochemistry. In this study, using immunodetection and immunopurification techniques with specific anti-SLPI immunoglobulin G (IgG), we show that SLPI is present as a native 14-kDa molecule in neutrophil cytosol. In addition, we demonstrate that SLPI is the major inhibitor of HLE present in neutrophil cytosol because pre-incubation with specific anti-SLPI IgG was able to inhibit completely the anti-HLE activity of the cytosol. SLPI can be secreted (probably in an inactive form) by neutrophils and its secretion is enhanced when the cells are stimulated with phorbol myristate acetate (PMA). Elafin, an elastase-specific inhibitor, is also present in minute amounts in neutrophil cytosol and its secretion can be up-regulated. The presence of SLPI in the cytosol of neutrophils may serve as a protective screen against proteinases spilling from azurophilic granules. An alternative or supplementary role may be the maintenance of a differentiated phenotype. PMID:9201260

  1. The STAT5 inhibitor pimozide decreases survival of chronic myelogenous leukemia cells resistant to kinase inhibitors

    PubMed Central

    Nelson, Erik A.; Walker, Sarah R.; Weisberg, Ellen; Bar-Natan, Michal; Barrett, Rosemary; Gashin, Laurie B.; Terrell, Shariya; Klitgaard, Josephine L.; Santo, Loredana; Addorio, Martha R.; Ebert, Benjamin L.; Griffin, James D.

    2011-01-01

    The transcription factor STAT5 is an essential mediator of the pathogenesis of chronic myelogenous leukemia (CML). In CML, the BCR/ABL fusion kinase causes the constitutive activation of STAT5, thereby driving the expression of genes promoting survival. BCR/ABL kinase inhibitors have become the mainstay of therapy for CML, although CML cells can develop resistance through mutations in BCR/ABL. To overcome this problem, we used a cell-based screen to identify drugs that inhibit STAT-dependent gene expression. Using this approach, we identified the psychotropic drug pimozide as a STAT5 inhibitor. Pimozide decreases STAT5 tyrosine phosphorylation, although it does not inhibit BCR/ABL or other tyrosine kinases. Furthermore, pimozide decreases the expression of STAT5 target genes and induces cell cycle arrest and apoptosis in CML cell lines. Pimozide also selectively inhibits colony formation of CD34+ bone marrow cells from CML patients. Importantly, pimozide induces similar effects in the presence of the T315I BCR/ABL mutation that renders the kinase resistant to presently available inhibitors. Simultaneously inhibiting STAT5 with pimozide and the kinase inhibitors imatinib or nilotinib shows enhanced effects in inhibiting STAT5 phosphorylation and in inducing apoptosis. Thus, targeting STAT5 may be an effective strategy for the treatment of CML and other myeloproliferative diseases. PMID:21233313

  2. Therapeutic potential of an orally effective small molecule inhibitor of plasminogen activator inhibitor for asthma.

    PubMed

    Liu, Rui-Ming; Eldridge, Stephanie; Watanabe, Nobuo; Deshane, Jessy; Kuo, Hui-Chien; Jiang, Chunsun; Wang, Yong; Liu, Gang; Schwiebert, Lisa; Miyata, Toshio; Thannickal, Victor J

    2016-02-15

    Asthma is one of the most common respiratory diseases. Although progress has been made in our understanding of airway pathology and many drugs are available to relieve asthma symptoms, there is no cure for chronic asthma. Plasminogen activator inhibitor 1 (PAI-1), a primary inhibitor of tissue-type and urokinase-type plasminogen activators, has pleiotropic functions besides suppression of fibrinolysis. In this study, we show that administration of TM5275, an orally effective small-molecule PAI-1 inhibitor, 25 days after ovalbumin (OVA) sensitization-challenge, significantly ameliorated airway hyperresponsiveness in an OVA-induced chronic asthma model. Furthermore, we show that TM5275 administration significantly attenuated OVA-induced infiltration of inflammatory cells (neutrophils, eosinophils, and monocytes), the increase in the levels of OVA-specific IgE and Th2 cytokines (IL-4 and IL-5), the production of mucin in the airways, and airway subepithelial fibrosis. Together, the results suggest that the PAI-1 inhibitor TM5275 may have therapeutic potential for asthma through suppressing eosinophilic allergic response and ameliorating airway remodeling. PMID:26702150

  3. Complex polysaccharides as PCR inhibitors in feces: Helicobacter pylori model.

    PubMed

    Monteiro, L; Bonnemaison, D; Vekris, A; Petry, K G; Bonnet, J; Vidal, R; Cabrita, J; Mégraud, F

    1997-04-01

    A model was developed to study inhibitors present in feces which prevent the use of PCR for the detection of Helicobacter pylori. A DNA fragment amplified with the same primers as H. pylori was used to spike samples before extraction by a modified QIAamp tissue method. Inhibitors, separated on an Ultrogel AcA44 column, were characterized. Inhibitors in feces are complex polysaccharides possibly originating from vegetable material in the diet. PMID:9157172

  4. Dipeptidyl peptidase-4 inhibitor for steroid-induced diabetes

    PubMed Central

    Yanai, Hidekatsu; Masui, Yoshinori; Yoshikawa, Reo; Kunimatsu, Junwa; Kaneko, Hiroshi

    2010-01-01

    The addition of the dipeptidyl peptidase-4 (DDP-4) inhibitor has been reported to achieve greater improvements in glucose metabolism with fewer adverse events compared to increasing the metformin dose in type 2 diabetic patients. We present a patient with steroid-induced diabetes whose blood glucose levels were ameliorated by the use of the DPP-4 inhibitor, showing that the DPP-4 inhibitors may be an effective and safe oral anti-diabetic drug for steroid-induced diabetes. PMID:21537433

  5. Aromatase inhibitors in men: effects and therapeutic options

    PubMed Central

    2011-01-01

    Aromatase inhibitors effectively delay epiphysial maturation in boys and improve testosterone levels in adult men Therefore, aromatase inhibitors may be used to increase adult height in boys with gonadotropin-independent precocious puberty, idiopathic short stature and constitutional delay of puberty. Long-term efficacy and safety of the use of aromatase inhibitors has not yet been established in males, however, and their routine use is therefore not yet recommended. PMID:21693046

  6. Natural compounds as corrosion inhibitors for highly cycled systems

    SciTech Connect

    Quraishi, M.A.; Farooqi, I.H.; Saini, P.A.

    1999-11-01

    Strict environmental legislations have led to the development of green inhibitors in recent years. In continuation of the authors` research work on development of green inhibitors, they have investigated the aqueous extracts of three plants namely: Azadirachta indica, Punica Granatum and Momordica charantia as corrosion inhibitors for mild steel in 3% NaCl using weight loss and electrochemical methods. All the investigated compounds exhibited excellent corrosion inhibition properties comparable to that of HEDP. Azadirachta showed better scale inhibition effect than HEDP.

  7. Replication and Inhibitors of Enteroviruses and Parechoviruses

    PubMed Central

    van der Linden, Lonneke; Wolthers, Katja C.; van Kuppeveld, Frank J.M.

    2015-01-01

    The Enterovirus (EV) and Parechovirus genera of the picornavirus family include many important human pathogens, including poliovirus, rhinovirus, EV-A71, EV-D68, and human parechoviruses (HPeV). They cause a wide variety of diseases, ranging from a simple common cold to life-threatening diseases such as encephalitis and myocarditis. At the moment, no antiviral therapy is available against these viruses and it is not feasible to develop vaccines against all EVs and HPeVs due to the great number of serotypes. Therefore, a lot of effort is being invested in the development of antiviral drugs. Both viral proteins and host proteins essential for virus replication can be used as targets for virus inhibitors. As such, a good understanding of the complex process of virus replication is pivotal in the design of antiviral strategies goes hand in hand with a good understanding of the complex process of virus replication. In this review, we will give an overview of the current state of knowledge of EV and HPeV replication and how this can be inhibited by small-molecule inhibitors. PMID:26266417

  8. HTCC: Broad Range Inhibitor of Coronavirus Entry

    PubMed Central

    Milewska, Aleksandra; Kaminski, Kamil; Ciejka, Justyna; Kosowicz, Katarzyna; Zeglen, Slawomir; Wojarski, Jacek; Nowakowska, Maria; Szczubiałka, Krzysztof; Pyrc, Krzysztof

    2016-01-01

    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. PMID:27249425

  9. SGLT2 Inhibitors: Benefit/Risk Balance.

    PubMed

    Scheen, André J

    2016-10-01

    Inhibitors of sodium-glucose cotransporters type 2 (SGLT2) reduce hyperglycemia by increasing urinary glucose excretion. They have been evaluated in patients with type 2 diabetes treated with diet/exercise, metformin, dual oral therapy or insulin. Three agents are available in Europe and the USA (canagliflozin, dapagliflozin, empagliflozin) and others are commercialized in Japan or in clinical development. SGLT2 inhibitors reduce glycated hemoglobin, with a minimal risk of hypoglycemia. They exert favorable effects beyond glucose control with consistent body weight, blood pressure, and serum uric acid reductions. Empagliflozin showed remarkable reductions in cardiovascular/all-cause mortality and in hospitalization for heart failure in patients with previous cardiovascular disease. Positive renal outcomes were also shown with empagliflozin. Mostly reported adverse events are genital mycotic infections, while urinary tract infections and events linked to volume depletion are rather rare. Concern about a risk of ketoacidosis and bone fractures has been recently raised, which deserves caution and further evaluation. PMID:27541294

  10. RNA aptamer inhibitors of a restriction endonuclease

    PubMed Central

    Mondragón, Estefanía; Maher, L. James

    2015-01-01

    Restriction endonucleases (REases) recognize and cleave short palindromic DNA sequences, protecting bacterial cells against bacteriophage infection by attacking foreign DNA. We are interested in the potential of folded RNA to mimic DNA, a concept that might be applied to inhibition of DNA-binding proteins. As a model system, we sought RNA aptamers against the REases BamHI, PacI and KpnI using systematic evolution of ligands by exponential enrichment (SELEX). After 20 rounds of selection under different stringent conditions, we identified the 10 most enriched RNA aptamers for each REase. Aptamers were screened for binding and specificity, and assayed for REase inhibition. We obtained eight high-affinity (Kd ∼12-30 nM) selective competitive inhibitors (IC50 ∼20-150 nM) for KpnI. Predicted RNA secondary structures were confirmed by in-line attack assay and a 38-nt derivative of the best anti-KpnI aptamer was sufficient for inhibition. These competitive inhibitors presumably act as KpnI binding site analogs, but lack the primary consensus KpnI cleavage sequence and are not cleaved by KpnI, making their potential mode of DNA mimicry fascinating. Anti-REase RNA aptamers could have value in studies of REase mechanism and may give clues to a code for designing RNAs that competitively inhibit DNA binding proteins including transcription factors. PMID:26184872

  11. CYP17 inhibitors for prostate cancer therapy

    PubMed Central

    Vasaitis, Tadas S.; Bruno, Robert D.; Njar, Vincent C. O.

    2010-01-01

    Prostate cancer (PC) is now the second most prevalent cause of death in men in the USA and Europe. At present, the major treatment options include surgical or medical castration. These strategies cause ablation of the production of testosterone (T), dihydrotestosterone (DHT) and related androgens by the testes. However, because these procedures do not affect adrenal, prostate and other tissues androgen production, they are often combined with androgen receptor antagonists to block their action. Indeed, recent studies have unequivocally established that in castration-resistant prostate cancer (CRPC) many androgen-regulated genes become re-expressed and tissue androgen levels increase despite low serum levels. Clearly, inhibition of the key enzyme which catalyzes the biosynthesis of androgens from pregnane precursors, 17α-hydroxy/17,20-lyase (hereafter referred to as CYP17) could prevent androgen production from all sources. Thus, total ablation of androgen production by potent CYP17 inhibitors may provide effective treatment of prostate cancer patients. This review highlights the role of androgen biosynthesis in the progression of prostate cancer and the impact of CYP17 inhibitors, such as ketoconazole, abiraterone acetate, VN/124-1 (TOK-001) and TAK-700 in the clinic and in clinical development. PMID:21092758

  12. Entry inhibitors: New advances in HCV treatment

    PubMed Central

    Qian, Xi-Jing; Zhu, Yong-Zhe; Zhao, Ping; Qi, Zhong-Tian

    2016-01-01

    Hepatitis C virus (HCV) infection affects approximately 3% of the world's population and causes chronic liver diseases, including liver fibrosis, cirrhosis, and hepatocellular carcinoma. Although current antiviral therapy comprising direct-acting antivirals (DAAs) can achieve a quite satisfying sustained virological response (SVR) rate, it is still limited by viral resistance, long treatment duration, combined adverse reactions, and high costs. Moreover, the currently marketed antivirals fail to prevent graft reinfections in HCV patients who receive liver transplantations, probably due to the cell-to-cell transmission of the virus, which is also one of the main reasons behind treatment failure. HCV entry is a highly orchestrated process involving initial attachment and binding, post-binding interactions with host cell factors, internalization, and fusion between the virion and the host cell membrane. Together, these processes provide multiple novel and promising targets for antiviral therapy. Most entry inhibitors target host cell components with high genetic barriers and eliminate viral infection from the very beginning of the viral life cycle. In future, the addition of entry inhibitors to a combination of treatment regimens might optimize and widen the prevention and treatment of HCV infection. This review summarizes the molecular mechanisms and prospects of the current preclinical and clinical development of antiviral agents targeting HCV entry. PMID:26733381

  13. Anti-platelet therapy: phosphodiesterase inhibitors

    PubMed Central

    Gresele, Paolo; Momi, Stefania; Falcinelli, Emanuela

    2011-01-01

    Inhibition of platelet aggregation can be achieved either by the blockade of membrane receptors or by interaction with intracellular signalling pathways. Cyclic adenosine 3′,5′-monophosphate (cAMP) and cyclic guanosine 3′,5′-monophosphate (cGMP) are two critical intracellular second messengers provided with strong inhibitory activity on fundamental platelet functions. Phosphodiesterases (PDEs), by catalysing the hydrolysis of cAMP and cGMP, limit the intracellular levels of cyclic nucleotides, thus regulating platelet function. The inhibition of PDEs may therefore exert a strong platelet inhibitory effect. Platelets possess three PDE isoforms (PDE2, PDE3 and PDE5), with different selectivity for cAMP and cGMP. Several nonselective or isoenzyme-selective PDE inhibitors have been developed, and some of them have entered clinical use as antiplatelet agents. This review focuses on the effect of PDE2, PDE3 and PDE5 inhibitors on platelet function and on the evidence for an antithrombotic action of some of them, and in particular of dipyridamole and cilostazol. PMID:21649691

  14. A novel molluscicide, corrosion inhibitor, and dispersant

    SciTech Connect

    Kreuser, R.T.; Vanlaer, A.; Damour, A.

    1997-12-01

    The efficacy of filming amines as corrosion inhibitors and dispersants in steam systems is well-documented. A novel formulation retains these functions of traditional filming amines and adds molluscicide capability for controlling macrofouling in fresh water and sea water. Criteria for this development included low toxicity to mammals and to non-target aquatic species, rapid biodegradation, and multifunctionality. Low mammalian toxicity and lack of other hazards exempt it from reporting requirements under SARA Title 3. Toxicity (LC{sub 50}) levels for rainbow trout and fathead minnow are higher than typical dosage rates. Biodegradation is rapid; half life is 22 hours in river water. By effectively dispersing slimes (along with biofilm, scale, and tubercles), it controls slimes without toxicity to biofilm organisms. As corrosion inhibitor, it reduces the open cell potential of metal surfaces by 50--200 millivolts and retards pitting and crevice corrosion. Its molluscicide activity gradually kills and disperses mussels, clams, and barnacles. The protective film, renewed by dosage for a brief period of time each day, proactively prevents scale and slime deposits and repels settling and adhesion by macrofouling species. Refinement of established technology has produced a multi-functional formulation that is safe to handle and has minimal impact on the environment.

  15. Novel inhibitors of Anthrax edema factor

    PubMed Central

    Chen, Deliang; Misra, Milind; Sower, Laurie; Peterson, Johnny W.; Kellogg, Glen E.; Schein, Catherine H.

    2008-01-01

    Several pathogenic bacteria produce adenylyl cyclase toxins, such as the edema factor (EF) of Bacillus anthracis. These disturb cellular metabolism by catalyzing production of excessive amounts of the regulatory molecule cAMP. Here, a structure-based method, where a 3D- pharmacophore that fit the active site of EF was constructed from fragments, was used to identify non-nucleotide inhibitors of EF. A library of small molecule fragments was docked to the EF- active site in existing crystal structures and those with the highest HINT scores were assembled into a 3D-pharmacophore. About 10,000 compounds, from over 2.7 million compounds in the ZINC database, had a similar molecular framework. These were ranked according to their docking scores, using methodology that was shown to achieve maximum accuracy (i.e., how well the docked position matched the experimentally determined site for ATP analogues in crystal structures of the complex). Finally, 19 diverse compounds with the best AutoDock binding/docking scores were assayed in a cell based assay for their ability to reduce cAMP secretion induced by EF. Four of the test compounds, from different structural groups, inhibited in the low micromolar range. One of these has a core structure common to phosphatase inhibitors previously identified by high-throughput assays of a diversity library. Thus, the fragment based pharmacophore identified a small number of diverse compounds for assay, and greatly enhanced the selection process of advanced lead compounds for combinatorial design. PMID:18620864

  16. Undecaprenyl diphosphate synthase inhibitors: antibacterial drug leads.

    PubMed

    Sinko, William; Wang, Yang; Zhu, Wei; Zhang, Yonghui; Feixas, Ferran; Cox, Courtney L; Mitchell, Douglas A; Oldfield, Eric; McCammon, J Andrew

    2014-07-10

    There is a significant need for new antibiotics due to the rise in drug resistance. Drugs such as methicillin and vancomycin target bacterial cell wall biosynthesis, but methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) have now arisen and are of major concern. Inhibitors acting on new targets in cell wall biosynthesis are thus of particular interest since they might also restore sensitivity to existing drugs, and the cis-prenyl transferase undecaprenyl diphosphate synthase (UPPS), essential for lipid I, lipid II, and thus, peptidoglycan biosynthesis, is one such target. We used 12 UPPS crystal structures to validate virtual screening models and then assayed 100 virtual hits (from 450,000 compounds) against UPPS from S. aureus and Escherichia coli. The most promising inhibitors (IC50 ∼2 μM, Ki ∼300 nM) had activity against MRSA, Listeria monocytogenes, Bacillus anthracis, and a vancomycin-resistant Enterococcus sp. with MIC or IC50 values in the 0.25-4 μg/mL range. Moreover, one compound (1), a rhodanine with close structural similarity to the commercial diabetes drug epalrestat, exhibited good activity as well as a fractional inhibitory concentration index (FICI) of 0.1 with methicillin against the community-acquired MRSA USA300 strain, indicating strong synergism. PMID:24827744

  17. Natural cholinesterase inhibitors from Myristica cinnamomea King.

    PubMed

    Abdul Wahab, Siti Mariam; Sivasothy, Yasodha; Liew, Sook Yee; Litaudon, Marc; Mohamad, Jamaludin; Awang, Khalijah

    2016-08-01

    A new acylphenol, malabaricone E (1) together with the known malabaricones A-C (2-4), maingayones A and B (5 and 6) and maingayic acid B (7) were isolated from the ethyl acetate extract of the fruits of Myristica cinnamomea King. Their structures were determined by 1D and 2D NMR techniques and LCMS-IT-TOF analysis. Compounds 3 (1.84±0.19 and 1.76±0.21μM, respectively) and 4 (1.94±0.27 and 2.80±0.49μM, respectively) were identified as dual inhibitors, with almost equal acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes inhibiting potentials. The Lineweaver-Burk plots of compounds 3 and 4 indicated that they were mixed-mode inhibitors. Based on the molecular docking studies, compounds 3 and 4 interacted with the peripheral anionic site (PAS), the catalytic triad and the oxyanion hole of the AChE. As for the BChE, while compound 3 interacted with the PAS, the catalytic triad and the oxyanion hole, compound 4 only interacted with the catalytic triad and the oxyanion hole. PMID:27236720

  18. Peptide deformylase inhibitors as potent antimycobacterial agents.

    PubMed

    Teo, Jeanette W P; Thayalan, Pamela; Beer, David; Yap, Amelia S L; Nanjundappa, Mahesh; Ngew, Xinyi; Duraiswamy, Jeyaraj; Liung, Sarah; Dartois, Veronique; Schreiber, Mark; Hasan, Samiul; Cynamon, Michael; Ryder, Neil S; Yang, Xia; Weidmann, Beat; Bracken, Kathryn; Dick, Thomas; Mukherjee, Kakoli

    2006-11-01

    Peptide deformylase (PDF) catalyzes the hydrolytic removal of the N-terminal formyl group from nascent proteins. This is an essential step in bacterial protein synthesis, making PDF an attractive target for antibacterial drug development. Essentiality of the def gene, encoding PDF from Mycobacterium tuberculosis, was demonstrated through genetic knockout experiments with Mycobacterium bovis BCG. PDF from M. tuberculosis strain H37Rv was cloned, expressed, and purified as an N-terminal histidine-tagged recombinant protein in Escherichia coli. A novel class of PDF inhibitors (PDF-I), the N-alkyl urea hydroxamic acids, were synthesized and evaluated for their activities against the M. tuberculosis PDF enzyme as well as their antimycobacterial effects. Several compounds from the new class had 50% inhibitory concentration (IC50) values of <100 nM. Some of the PDF-I displayed antibacterial activity against M. tuberculosis, including MDR strains with MIC90 values of <1 microM. Pharmacokinetic studies of potential leads showed that the compounds were orally bioavailable. Spontaneous resistance towards these inhibitors arose at a frequency of < or =5 x 10(-7) in M. bovis BCG. DNA sequence analysis of several spontaneous PDF-I-resistant mutants revealed that half of the mutants had acquired point mutations in their formyl methyltransferase gene (fmt), which formylated Met-tRNA. The results from this study validate M. tuberculosis PDF as a drug target and suggest that this class of compounds have the potential to be developed as novel antimycobacterial agents. PMID:16966397

  19. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, Benjamin A.; Whitlow, Eugene P.

    1998-09-22

    A method of inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425.degree. F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25.degree. C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425.degree. F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer.

  20. Replication and Inhibitors of Enteroviruses and Parechoviruses.

    PubMed

    van der Linden, Lonneke; Wolthers, Katja C; van Kuppeveld, Frank J M

    2015-08-01

    The Enterovirus (EV) and Parechovirus genera of the picornavirus family include many important human pathogens, including poliovirus, rhinovirus, EV-A71, EV-D68, and human parechoviruses (HPeV). They cause a wide variety of diseases, ranging from a simple common cold to life-threatening diseases such as encephalitis and myocarditis. At the moment, no antiviral therapy is available against these viruses and it is not feasible to develop vaccines against all EVs and HPeVs due to the great number of serotypes. Therefore, a lot of effort is being invested in the development of antiviral drugs. Both viral proteins and host proteins essential for virus replication can be used as targets for virus inhibitors. As such, a good understanding of the complex process of virus replication is pivotal in the design of antiviral strategies goes hand in hand with a good understanding of the complex process of virus replication. In this review, we will give an overview of the current state of knowledge of EV and HPeV replication and how this can be inhibited by small-molecule inhibitors. PMID:26266417

  1. Entry inhibitors: New advances in HCV treatment.

    PubMed

    Qian, Xi-Jing; Zhu, Yong-Zhe; Zhao, Ping; Qi, Zhong-Tian

    2016-01-01

    Hepatitis C virus (HCV) infection affects approximately 3% of the world's population and causes chronic liver diseases, including liver fibrosis, cirrhosis, and hepatocellular carcinoma. Although current antiviral therapy comprising direct-acting antivirals (DAAs) can achieve a quite satisfying sustained virological response (SVR) rate, it is still limited by viral resistance, long treatment duration, combined adverse reactions, and high costs. Moreover, the currently marketed antivirals fail to prevent graft reinfections in HCV patients who receive liver transplantations, probably due to the cell-to-cell transmission of the virus, which is also one of the main reasons behind treatment failure. HCV entry is a highly orchestrated process involving initial attachment and binding, post-binding interactions with host cell factors, internalization, and fusion between the virion and the host cell membrane. Together, these processes provide multiple novel and promising targets for antiviral therapy. Most entry inhibitors target host cell components with high genetic barriers and eliminate viral infection from the very beginning of the viral life cycle. In future, the addition of entry inhibitors to a combination of treatment regimens might optimize and widen the prevention and treatment of HCV infection. This review summarizes the molecular mechanisms and prospects of the current preclinical and clinical development of antiviral agents targeting HCV entry. PMID:26733381

  2. Identification and Validation of Novel PERK Inhibitors

    PubMed Central

    2015-01-01

    PERK, as one of the principle unfolded protein response signal transducers, is believed to be associated with many human diseases, such as cancer and type-II diabetes. There has been increasing effort to discover potent PERK inhibitors due to its potential therapeutic interest. In this study, a computer-based virtual screening approach is employed to discover novel PERK inhibitors, followed by experimental validation. Using a focused library, we show that a consensus approach, combining pharmacophore modeling and docking, can be more cost-effective than using either approach alone. It is also demonstrated that the conformational flexibility near the active site is an important consideration in structure-based docking and can be addressed by using molecular dynamics. The consensus approach has further been applied to screen the ZINC lead-like database, resulting in the identification of 10 active compounds, two of which show IC50 values that are less than 10 μM in a dose–response assay. PMID:24745945

  3. Polyphenol Compound as a Transcription Factor Inhibitor.

    PubMed

    Park, Seyeon

    2015-11-01

    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)). PMID:26529010

  4. Polyphenol Compound as a Transcription Factor Inhibitor

    PubMed Central

    Park, Seyeon

    2015-01-01

    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)). PMID:26529010

  5. Structure activity relationships of human galactokinase inhibitors.

    PubMed

    Liu, Li; Tang, Manshu; Walsh, Martin J; Brimacombe, Kyle R; Pragani, Rajan; Tanega, Cordelle; Rohde, Jason M; Baker, Heather L; Fernandez, Elizabeth; Blackman, Burchelle; Bougie, James M; Leister, William H; Auld, Douglas S; Shen, Min; Lai, Kent; Boxer, Matthew B

    2015-02-01

    Classic Galactosemia is a rare inborn error of metabolism that is caused by deficiency of galactose-1-phosphate uridyltransferase (GALT), an enzyme within the Leloir pathway that is responsible for the conversion of galactose-1-phosphate (gal-1-p) and UDP-glucose to glucose-1-phosphate and UDP-galactose. This deficiency results in elevated intracellular concentrations of its substrate, gal-1-p, and this increased concentration is believed to be the major pathogenic mechanism in Classic Galactosemia. Galactokinase (GALK) is an upstream enzyme of GALT in the Leloir pathway and is responsible for conversion of galactose and ATP to gal-1-p and ADP. Therefore, it was hypothesized that the identification of a small-molecule inhibitor of human GALK would act to prevent the accumulation of gal-1-p and offer a novel entry therapy for this disorder. Herein we describe a quantitative high-throughput screening campaign that identified a single chemotype that was optimized and validated as a GALK inhibitor. PMID:25553891

  6. Proton pump inhibitors decrease melanogenesis in melanocytes

    PubMed Central

    BAEK, SEUNG-HWA; LEE, SANG-HAN

    2015-01-01

    Proton pump inhibitors (PPIs) are widely used as inhibitors of gastric juice secretion for treatment of gastroesophageal reflux disease. However, there are no previous studies of the effects on melanogenesis resulting from PPI treatments. Therefore, the aim of the present study was to investigate the effects of PPIs on melanogenesis in melan-a cells derived from immortalized mouse melanocytes. Tyrosinase activity and copper-chelating activity were measured spectrophotometrically. In addition, the melanin content and viability of melan-a cells treated with PPIs were assessed and the mRNA levels of melanogenesis-associated genes were measured by reverse transcription-polymerase chain reaction. Treatment with rabeprazole, but not the other PPIs tested, resulted in strong, dose-dependent inhibition of mushroom tyrosinase (TYR). By contrast, each of the PPIs tested exhibited copper-chelating activity. Treatment of melan-a cells with 100 µM concentrations of the PPIs resulted in significantly reduced melanin synthesis and reduced expression of several melanogenesis-associated genes, including TYR, TYR-related protein-1 (TRP-1) and TRP-2, and microphthalmia-associated transcription factor, but did not result in cytotoxic effects. These results suggest that PPIs inhibit melanin biosynthesis in melan-a cells via the downregulation of melanogenesis-associated genes. Furthermore, the findings indicate that PPIs in general could be utilized as skin-whitening agents and/or as biomaterial for treating hyperpigmentation disorders. PMID:26405553

  7. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, B.A.; Whitlow, E.P.

    1998-09-22

    A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

  8. Discovery of Biarylaminoquinazolines as Novel Tubulin Polymerization Inhibitors

    PubMed Central

    Ferrarese, Alessandro; Brun, Paola; Castagliuolo, Ignazio; Conconi, Maria Teresa; La Regina, Giuseppe; Bai, Ruoli; Silvestri, Romano; Hamel, Ernest; Chilin, Adriana

    2014-01-01

    Cell cycle experiments with our previously reported 4-biphenylaminoquinazoline (1–3) multityrosine kinase inhibitors revealed an activity profile resembling that of known tubulin polymerization inhibitors. Novel 4-biarylaminoquinazoline analogues of compound 2 were synthesized and evaluated as inhibitors of several tyrosine kinases and of tubulin. Although compounds 1–3 acted as dual inhibitors, the heterobiaryl analogues possessed only anti-tubulin properties and targeted the colchicine site. Furthermore, molecular modeling studies allowed the rationalization of the pharmacodynamic properties of the compounds. PMID:24801610

  9. Discovery of a selective irreversible BMX inhibitor for prostate cancer.

    PubMed

    Liu, Feiyang; Zhang, Xin; Weisberg, Ellen; Chen, Sen; Hur, Wooyoung; Wu, Hong; Zhao, Zheng; Wang, Wenchao; Mao, Mao; Cai, Changmeng; Simon, Nicholas I; Sanda, Takaomi; Wang, Jinhua; Look, A Thomas; Griffin, James D; Balk, Steven P; Liu, Qingsong; Gray, Nathanael S

    2013-07-19

    BMX is a member of the TEC family of nonreceptor tyrosine kinases. We have used structure-based drug design in conjunction with kinome profiling to develop a potent, selective, and irreversible BMX kinase inhibitor, BMX-IN-1, which covalently modifies Cys496. BMX-IN-1 inhibits the proliferation of Tel-BMX-transformed Ba/F3 cells at two digit nanomolar concentrations but requires single digit micromolar concentrations to inhibit the proliferation of prostate cancer cell lines. Using a combinatorial kinase inhibitor screening strategy, we discovered that the allosteric Akt inhibitor, MK2206, is able to potentiate BMX inhibitor's antiproliferation efficacy against prostate cancer cells. PMID:23594111

  10. Tumor necrosis factor inhibitors – state of knowledge

    PubMed Central

    Lis, Krzysztof; Kuzawińska, Olga

    2014-01-01

    Tumor necrosis factor (TNF) is considered a major proinflammatory cytokine, affecting various aspects of the immune reaction. All five TNF inhibitors currently available on the market (i.e., etanercept, infliximab, adalimumab, certolizumab and golimumab) are top sellers, although indicated only in autoimmune diseases, including rheumatoid arthritis, Crohn's disease and psoriasis. This article briefly discusses the background and place for TNF inhibitors in modern therapy. The main safety aspects of TNF inhibitor administration are described in particular, with special consideration of the available meta-analyses. Finally, perspectives on the next-generation TNF inhibitors and their use in the clinic are given. PMID:25624856

  11. Synthesis and In Vitro Evaluation of Aspartate Transcarbamoylase Inhibitors

    PubMed Central

    Coudray, Laëtitia; Pennebaker, Anne F.; Montchamp, Jean-Luc

    2009-01-01

    The design, synthesis, and evaluation of a series of novel inhibitors of aspartate transcarbamoylase (ATCase) are reported. Several submicromolar phosphorus-containing inhibitors are described, but all-carboxylate compounds are inactive. Compounds were synthesized to probe the postulated cyclic transition-state of the enzyme-catalyzed reaction. In addition, the associated role of the protonation state at the phosphorus acid moiety was evaluated using phosphinic and carboxylic acids. Although none of the synthesized inhibitors is more potent than N-phosphonacetyl-L-aspartate (PALA), the compounds provide useful mechanistic information, as well as the basis for the design of future inhibitors and/or prodrugs. PMID:19828320

  12. Squash inhibitors: from structural motifs to macrocyclic knottins.

    PubMed

    Chiche, Laurent; Heitz, Annie; Gelly, Jean-Christophe; Gracy, Jérôme; Chau, Pham T T; Ha, Phan T; Hernandez, Jean-François; Le-Nguyen, Dung

    2004-10-01

    In this article, we will first introduce the squash inhibitor, a well established family of highly potent canonical serine proteinase inhibitors isolated from Cucurbitaceae. The squash inhibitors were among the first discovered proteins with the typical knottin fold shared by numerous peptides extracted from plants, animals and fungi. Knottins contain three knotted disulfide bridges, two of them arranged as a Cystine-Stabilized Beta-sheet motif. In contrast to cyclotides for which no natural linear homolog is known, most squash inhibitors are linear. However, Momordica cochinchinensis Trypsin Inhibitor-I and (MCoTI-I and -II), 34-residue squash inhibitors isolated from seeds of a common Cucurbitaceae from Vietnam, were recently shown to be macrocyclic. In these circular squash inhibitors, a short peptide linker connects residues that correspond to the N- and C-termini in homologous linear squash inhibitors. In this review we present the isolation, characterization, chemical synthesis, and activity of these macrocyclic knottins. The solution structure of MCoTI-II will be compared with topologically similar cyclotides, homologous linear squash inhibitors and other knottins, and potential applications of such scaffolds will be discussed. PMID:15551519

  13. Inhibitory effects of respiration inhibitors on aflatoxin production.

    PubMed

    Sakuda, Shohei; Prabowo, Diyan Febri; Takagi, Keiko; Shiomi, Kazuro; Mori, Mihoko; Ōmura, Satoshi; Nagasawa, Hiromichi

    2014-04-01

    Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A) inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III) and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control. PMID:24674936

  14. Inhibitory Effects of Respiration Inhibitors on Aflatoxin Production

    PubMed Central

    Sakuda, Shohei; Prabowo, Diyan Febri; Takagi, Keiko; Shiomi, Kazuro; Mori, Mihoko; Ōmura, Satoshi; Nagasawa, Hiromichi

    2014-01-01

    Aflatoxin production inhibitors, which do not inhibit the growth of aflatoxigenic fungi, may be used to control aflatoxin without incurring a rapid spread of resistant strains. A respiration inhibitor that inhibits aflatoxin production was identified during a screening process for natural, aflatoxin-production inhibitors. This prompted us to evaluate respiration inhibitors as potential aflatoxin control agents. The inhibitory activities of four natural inhibitors, seven synthetic miticides, and nine synthetic fungicides were evaluated on aflatoxin production in Aspergillus parasiticus. All of the natural inhibitors (rotenone, siccanin, aptenin A5, and antimycin A) inhibited fungal aflatoxin production with IC50 values around 10 µM. Among the synthetic miticides, pyridaben, fluacrypyrim, and tolfenpyrad exhibited strong inhibitory activities with IC50 values less than 0.2 µM, whereas cyflumetofen did not show significant inhibitory activity. Of the synthetic fungicides, boscalid, pyribencarb, azoxystrobin, pyraclostrobin, and kresoxim-methyl demonstrated strong inhibitory activities, with IC50 values less than 0.5 µM. Fungal growth was not significantly affected by any of the inhibitors tested at concentrations used. There was no correlation observed between the targets of respiration inhibitors (complexes I, II, and III) and their IC50 values for aflatoxin-production inhibitory activity. This study suggests that respiration inhibitors, including commonly used pesticides, are useful for aflatoxin control. PMID:24674936

  15. Solderability preservation through the use of organic inhibitors

    SciTech Connect

    Sorensen, N.R.; Hosking, F.M.

    1994-12-01

    Organic inhibitors can be used to prevent corrosion of metals and have application in the electronics industry as solderability preservatives. We have developed a model to describe the action of two inhibitors (benzotriazole and imidazole) during the environmental aging and soldering process. The inhibitors bond with the metal surface and form a barrier that prevents or retards oxidation. At soldering temperatures, the metal-organic complex breaks down leaving an oxide-free metal surface that allows excellent wetting by molten solder. The presence of the inhibitor retards the wetting rate relative to clean copper, but provides a vast improvement relative to oxidized copper.

  16. Molecular basis underlying resistance to Mps1/TTK inhibitors

    PubMed Central

    Koch, A; Maia, A; Janssen, A; Medema, R H

    2016-01-01

    Mps1/TTK is a dual-specificity kinase, with an essential role in mitotic checkpoint signaling, which has emerged as a potential target in cancer therapy. Several Mps1/TTK small-molecule inhibitors have been described that exhibit promising activity in cell culture and xenograft models. Here, we investigated whether cancer cells can develop resistance to these drugs. To this end, we treated various cancer cell lines with sublethal concentrations of a potent Mps1/TTK inhibitor in order to isolate inhibitor-resistant monoclonal cell lines. We identified four point mutations in the catalytic domain of Mps1/TTK that gave rise to inhibitor resistance but retained wild-type catalytic activity. Interestingly, cross-resistance of the identified mutations to other Mps1/TTK inhibitors is limited. Our studies predict that Mps1/TTK inhibitor-resistant tumor cells can arise through the acquisition of mutations in the adenosine triphosphate-binding pocket of the kinase that prevent stable binding of the inhibitors. In addition, our results suggest that combinations of inhibitors could be used to prevent acquisition of drug resistance. Interestingly, cross-resistance seems nonspecific for inhibitor scaffolds, a notion that can be exploited in future drug design to evict possible resistance mutations during clinical treatment. PMID:26364596

  17. Behaviour of tetramine inhibitors during pickling of hot rolled steels

    NASA Astrophysics Data System (ADS)

    Cornu, Marie-José; Koltsov, Alexey; Nicolas, Sabrina; Colom, Lydia; Dossot, Manuel

    2014-02-01

    To avoid the dissolution of steel in industrial pickling process, tetramine inhibitors are added to the pickling bath. This study is devoted to the understanding of the action mechanism of these inhibitors in hydrochloric and sulphuric baths on non-alloyed and alloyed steels. Pickling experiments and characterization with XPS, Raman and infrared spectroscopies have shown that inhibitors work only in acid media and leached out from the steel surfaces during the rinsing operation just after pickling. The effectiveness of inhibitors depends on the acid media and the temperature. Experimental data are consistent with a surface mechanism, i.e., the so-called "outer-sphere" adsorption.

  18. [Prospects for the design of new therapeutically significant protease inhibitors based on knottins and sunflower seed trypsin inhibitor (SFTI 1)].

    PubMed

    Kuznetsova, S S; Kolesanova, E F; Talanova, A V; Veselovsky, A V

    2016-05-01

    Plant seed knottins, mainly from the Cucurbitacea family, and sunflower seed trypsin inhibitor (SFTI 1) are the most low-molecular canonical peptide inhibitors of serine proteases. High efficiency of inhibition of various serine proteases, structure rigidity together with the possibility of limited variations of amino acid sequences, high chemical stability, lack of toxic properties, opportunity of production by either chemical synthesis or use of heterologous expression systems make these inhibitors attractive templates for design of new compounds for regulation of therapeutically significant serine protease activities. Hence the design of such compounds represents a prospective research field. The review considers structural characteristics of these inhibitors, their properties, methods of preparation and design of new analogs. Examples of successful employment of natural serine protease inhibitors belonging to knottin family and SFTI 1 as templates for the design of highly specific inhibitors of certain proteases are given. PMID:27562989

  19. CHZ868, a Type II JAK2 Inhibitor, Reverses Type I JAK Inhibitor Persistence and Demonstrates Efficacy in Myeloproliferative Neoplasms

    PubMed Central

    Meyer, Sara C.; Keller, Matthew D.; Chiu, Sophia; Koppikar, Priya; Guryanova, Olga A.; Rapaport, Franck; Xu, Ke; Manova, Katia; Pankov, Dmitry; O’Reilly, Richard J.; Kleppe, Maria; McKenney, Anna Sophia; Shih, Alan H.; Shank, Kaitlyn; Ahn, Jihae; Papalexi, Eftymia; Spitzer, Barbara; Socci, Nick; Viale, Agnes; Mandon, Emeline; Ebel, Nicolas; Andraos, Rita; Rubert, Joëlle; Dammassa, Ernesta; Romanet, Vincent; Dölemeyer, Arno; Zender, Michael; Heinlein, Melanie; Rampal, Rajit; Weinberg, Rona Singer; Hoffman, Ron; Sellers, William R.; Hofmann, Francesco; Murakami, Masato; Baffert, Fabienne; Gaul, Christoph; Radimerski, Thomas; Levine, Ross L.

    2015-01-01

    Summary Although clinically tested JAK inhibitors reduce splenomegaly and systemic symptoms, molecular responses are not observed in most myeloproliferative neoplasms (MPN) patients. We previously demonstrated that MPN cells become persistent to type I JAK inhibitors that bind the active conformation of JAK2. We investigated if CHZ868, a type II JAK inhibitor, would demonstrate activity in JAK inhibitor persistent cells, murine MPN models, and MPN patient samples. JAK2- and MPL-mutant cell lines were sensitive to CHZ868, including type I JAK inhibitor persistent cells. CHZ868 showed significant activity in murine MPN models and induced reductions in mutant allele burden not observed with type I JAK inhibitors. These data demonstrate that type II JAK inhibition is a viable therapeutic approach for MPN patients. PMID:26175413

  20. Identification of fermentation inhibitors in wood hydrolyzates and removal of inhibitors by ion exchange and liquid-liquid extraction

    NASA Astrophysics Data System (ADS)

    Luo, Caidian

    1998-12-01

    Common methods employed in the ethanol production from biomass consist of chemical or enzymatic degradation of biomass into sugars and then fermentation of sugars into ethanol or other chemicals. However, some degradation products severely inhibit the fermentation processes and substantially reduce the efficiency of ethanol production. How to remove inhibitors from the reaction product mixture and increase the production efficiency are critical in the commercialization of any processes of energy from biomass. The present study has investigated anion exchange and liquid-liquid extraction as potential methods for inhibitor removal. An analytical method has been developed to identify the fermentation inhibitors in a hydrolyzate. The majority of inhibitors present in hybrid poplar hydrolyzate have positively been identified. Ion exchange with weak basic Dowex-MWA-1 resin has been proved to be an effective mean to remove fermentation inhibitors from hybrid poplar hydrolyzate and significantly increase the fermentation productivity. Extraction with n-butanol might be a preferred way to remove inhibitors from wood hydrolyzates and improve the fermentability of sugars in the hydrolyzates. n-Butanol also removes some glucose, mannose and xylose from the hydrolyzate. Inhibitor identification reveals that lignin and sugar degradation compounds including both aromatic and aliphatic aldehydes and carboxylic acids formed in hydrolysis, plus fatty acids and other components from wood extractives are major fermentation inhibitors in Sacchromyces cerevisiae fermentation. There are 35 components identified as fermentation inhibitors. Among them, 4-hydroxy benzoic acid, 3,4-dihydroxy benzoic acid, syringic acid, syringaldehyde, and ferulic acid are among the most abundant aromatic inhibitors in hybrid poplar hydrolyzate. The conversion of aldehyde groups into carboxylic acid groups in the nitric acid catalyzed hydrolysis reduces the toxicity of the hydrolyzate. A wide spectrum of

  1. The presence and inactivation of trypsin inhibitors, tannins, lectins and amylase inhibitors in legume seeds during germination. A review.

    PubMed

    Savelkoul, F H; van der Poel, A F; Tamminga, S

    1992-01-01

    During the germination of legume seeds, enzymes become active in order to degrade starch, storage-protein and proteinaceous antinutritional factors. The degradation of storage-protein is necessary to make peptides and amino acids available in order to stimulate seed growth and early plant growth. Proteinaceous antinutritional factors such as amylase inhibitors, lectins and trypsin inhibitors are present in legume seeds and protect them against predators. However, during germination, they degrade to a lower level by the action of several enzymes. The effect of germination on the content and activity of amylase inhibitors, lectins, tannins and trypsin inhibitors is discussed. PMID:1372122

  2. Hepatotoxicity of nucleoside reverse transcriptase inhibitors.

    PubMed

    Montessori, Valentina; Harris, Marianne; Montaner, Julio S G

    2003-05-01

    Hepatotoxicity is an adverse effect of all available classes of antiretrovirals, including nucleoside reverse transcriptase inhibitors (NRTI). A syndrome of hepatic steatosis and lactic acidosis has been recognized as a rare, potentially fatal complication since the advent of NRTI monotherapy in the early 1990s. Today, NRTI remain the backbone of antiretroviral combination regimens, and, with the success of current treatment strategies, exposure to two or more of these agents may occur over a number of years. Hepatic steatosis and lactic acidosis are accordingly being observed more frequently, along with a more recently recognized syndrome of chronic hyperlactatemia. These as well as other adverse effects of NRTI are mediated by inhibition of human DNA polymerase gamma, resulting in mitochondrial dysfunction in the liver and other tissues. Early recognition and intervention are essential to avert serious outcomes. PMID:12800069

  3. Specific inhibitors of ammonia oxidation in Nitrosomonas.

    PubMed

    Hooper, A B; Terry, K R

    1973-08-01

    The following compounds or treatments have been shown to inhibit the oxidation of ammonia, but not the oxidation of hydroxylamine in cells of Nitrosomonas: (i) metal-binding agents such as allylthiourea or potassium cyanide; (ii) compounds such as SKF 525 which interact with cytochrome P-450 of mammalian microsomes; (iii) carbon monoxide; (iv) inhibitors of catalase, peroxidase, and amine oxidases such as thiosemicarbazide, ethylxanthate, and iproniazid, respectively; (v) uncouplers of oxidative phosphorylation such as m-chlorocarbonylcyanidephenylhydrazone; (vi) electron acceptors such as phenazine methosulfate; (vii) compounds such as methanol or N(2)O which react with free radicals; and (viii) illumination with 420 lux (5,000 foot candles) of light. PMID:4725614

  4. Molecular modeling of auxin transport inhibitors

    SciTech Connect

    Gardner, G.; Black-Schaefer, C.; Bures, M.G. )

    1990-05-01

    Molecular modeling techniques have been used to study the chemical and steric properties of auxin transport inhibitors. These bind to a specific site on the plant plasma membrane characterized by its affinity for N-1-naphthylphthalamic acid (NPA). A three-dimensional model was derived from critical features of ligands for the NPA receptor, and a suggested binding conformation is proposed. This model, along with three-dimensional structural searching techniques, was then used to search the Abbott corporate database of chemical structures. Of the 467 compounds that satisfied the search criteria, 77 representative molecules were evaluated for their ability to compete for ({sup 3}H)NPA binding to corn microsomal membranes. Nineteen showed activity that ranged from 16 to 85% of the maximum NPA binding. Four of the most active of these, from chemical classes not included in the original compound set, also inhibited polar auxin transport through corn coleoptile sections.

  5. Can proton pump inhibitors accentuate skin aging?

    PubMed

    Namazi, Mohammad Reza; Jowkar, Farideh

    2010-02-01

    Skin aging has long been important to human beings and in recent years this field has received tremendous attention by both researchers and the general population. Cutaneous aging includes two distinct phenomena, intrinsic aging and photoaging, and is characterized mainly by the loss of collagen fibers from dermis. Proton pump inhibitors (PPIs) are widely prescribed gastric acid-reducing agents that are usually consumed for long periods in some conditions such as gastroesophageal reflux disease. We suggest that PPIs can accentuate skin aging by two mechanisms. First, through increasing intralysosomal PH, PPIs can suppress transforming growth factor-beta (TGFbeta) processing and consequently decrease its secretion. Second, through inhibiting MNK, a P-type ATPase with steady-state localization at the trans-Golgi network, PPIs can hamper copper transport and consequently curb lysyl oxidase activity. PMID:20470945

  6. Protein-Inhibitor Interaction Studies Using NMR

    PubMed Central

    Ishima, Rieko

    2015-01-01

    Solution-state NMR has been widely applied to determine the three-dimensional structure, dynamics, and molecular interactions of proteins. The designs of experiments used in protein NMR differ from those used for small-molecule NMR, primarily because the information available prior to an experiment, such as molecular mass and knowledge of the primary structure, is unique for proteins compared to small molecules. In this review article, protein NMR for structural biology is introduced with comparisons to small-molecule NMR, such as descriptions of labeling strategies and the effects of molecular dynamics on relaxation. Next, applications for protein NMR are reviewed, especially practical aspects for protein-observed ligand-protein interaction studies. Overall, the following topics are described: (1) characteristics of protein NMR, (2) methods to detect protein-ligand interactions by NMR, and (3) practical aspects of carrying out protein-observed inhibitor-protein interaction studies. PMID:26361636

  7. Heterocyclic compounds as carbonic anhydrase inhibitor.

    PubMed

    Husain, Asif; Madhesia, Diwakar

    2012-12-01

    The carbonic anhydrases (CAs, EC 4.2.1.1) constitute interesting targets for the design of pharmacological agents useful in the treatment or prevention of a variety of disorders such as, glaucoma, acid-base disequilibria, epilepsy, and other neuromuscular diseases, altitude sickness, edema, and obesity. A quite new and unexpected application of the CA inhibitors (CAIs) is with regard to their potential use in the management (imaging and treatment) of hypoxic tumors. A series of sulfonamides, including some clinically used derivatives like acetazolamide, methazolamide, ethoxzolamide, dichlorophenamide, dorzolamide, brinzolamide, benzolamide, and sulpiride, or indisulam, a compound in clinical development as antitumor drug, as well as the sulfamate antiepileptic drug topiramate have been reported to inhibit various human carbonic anhydrase isozyme. Various heterocyclic sulfonamides have been reported in this review with their potency to inhibit different carbonic anhydrases isozymes. PMID:21981003

  8. [PCSK9 inhibitors : Recommendations for patient selection].

    PubMed

    Laufs, U; Custodis, F; Werner, C

    2016-06-01

    The 2 or 4‑week subcutaneous therapy with the recently approved antibodies alirocumab and evolocumab for inhibition of proprotein convertase subtilisin-kexin type 9 (PCSK9) reduces low-density lipoprotein cholesterol (LDL-C) in addition to statins and ezetimibe by 50-60 %. The therapy is well-tolerated. The safety profile in the published studies is comparable to placebo. Outcome data and information on long-term safety and the influence on cardiovascular events are not yet available but the results of several large trials are expected in 2016-2018. At present (spring 2016) PCSK9 inhibitors represent an option for selected patients with a high cardiovascular risk and high LDL-C despite treatment with the maximum tolerated oral lipid-lowering therapy. This group includes selected patients with familial hypercholesterolemia and high-risk individuals with statin-associated muscle symptoms (SAMS). PMID:27207595

  9. Chemical Inhibitors of Epigenetic Methyllysine Reader Proteins.

    PubMed

    Milosevich, Natalia; Hof, Fraser

    2016-03-22

    Protein methylation is a common post-translational modification with diverse biological functions. Methyllysine reader proteins are increasingly a focus of epigenetics research and play important roles in regulating many cellular processes. These reader proteins are vital players in development, cell cycle regulation, stress responses, oncogenesis, and other disease pathways. The recent emergence of a small number of chemical inhibitors for methyllysine reader proteins supports the viability of these proteins as targets for drug development. This article introduces the biochemistry and biology of methyllysine reader proteins, provides an overview of functions for those families of readers that have been targeted to date (MBT, PHD, tudor, and chromodomains), and reviews the development of synthetic agents that directly block their methyllysine reading functions. PMID:26650180

  10. Efficacy of topical calcineurin inhibitors in vitiligo.

    PubMed

    Wong, Russell; Lin, Andrew N

    2013-04-01

    Topical tacrolimus and pimecrolimus are indicated for the treatment of atopic dermatitis, but they have been studied in many off-label uses. We reviewed the English language literature to define their roles in treatment of vitiligo. Double-blind studies show that tacrolimus 0.1% ointment combined with excimer laser is superior to placebo, especially for UV resistant areas, such as bony prominences of the extremities. When used alone, tacrolimus 0.1% ointment is almost as effective as clobetasol propionate 0.05% ointment. Other studies suggest it can also be effective for facial lesions. Double blind studies show that pimecrolimus 1% cream combined with narrow band UVB is superior to placebo, especially for facial lesions. Additional studies would further clarify the role of topical calcineurin inhibitors in vitiligo. PMID:23331250

  11. Antithrombin, an Important Inhibitor in Blood Clots.

    PubMed

    Zhu, Ying; Cong, Qing-Wei; Liu, Yue; Wan, Chun-Ling; Yu, Tao; He, Guang; He, Lin; Cai, Lei; Chou, Kuo-Chen

    2016-01-01

    Blood coagulation is healthy and lifesaving because it can stop bleeding. It can, however, be a troublemaker as well, causing serious medical problems including heart attack and stroke. Body has complex blood coagulation cascade to modulate the blood clots. In the environment of plasma, the blood coagulation cascade is regulated by antithrombin, which is deemed one of the most important serine protease inhibitors. It inhibits thrombin; it can inhibit factors IXa and Xa as well. Interestingly, its inhibitory ability will be significantly increased with the existence of heparin. In this minireview paper, we are to summarize the structural features of antithrombin, as well as its heparin binding modes and anti-coagulation mechanisms, in hopes that the discussion and analysis presented in this paper can stimulate new strategies to find more effective approaches or compounds to modulate the antithrombin. PMID:26411319

  12. Inhibitors of Kallikrein in Human Plasma

    PubMed Central

    McConnell, David J.

    1972-01-01

    Human plasma was fractionated by ammonium sulfate precipitation, DEAE-cellulose chromatography, and Sephadex G-200 gel filtration to determine which method would give the greatest number of clearly separable kallikrein inhibitory peaks. With G-200 gel filtration three peaks could be separated which were demonstrated to contain α2-macroglobulin, C1̄ inactivator, and α1-antitrypsin. No other kallikrein inhibitors could be identified. The fractions containing C1̄ inactivator and α2-macroglobulin appeared to be more effective against kallikrein than that containing α1-antitrypsin. A patient with hereditary angioneurotic edema was shown to have an abnormal C1̄ inactivator protein capable of interfering with kallikrein's biologic, but not its esterolytic activity. Heat-treated human plasma, a commonly used source of kininogen for experiments with kallikrein, was shown to have kallikrein inhibitory activity. PMID:4113391

  13. New Acetylcholinesterase Inhibitors for Alzheimer's Disease

    PubMed Central

    Mehta, Mona; Adem, Abdu; Sabbagh, Marwan

    2012-01-01

    Acetylcholinesterase (AChE) remains a highly viable target for the symptomatic improvement in Alzheimer's disease (AD) because cholinergic deficit is a consistent and early finding in AD. The treatment approach of inhibiting peripheral AchE for myasthenia gravis had effectively proven that AchE inhibition was a reachable therapeutic target. Subsequently tacrine, donepezil, rivastigmine, and galantamine were developed and approved for the symptomatic treatment of AD. Since then, multiple cholinesterase inhibitors (ChEI) continue to be developed. These include newer ChEIs, naturally derived ChEIs, hybrids, and synthetic analogues. In this paper, we summarize the different types of ChEIs in development and their respective mechanisms of actions. This pharmacological approach continues to be active with many promising compounds. PMID:22216416

  14. Coumarins as cholinesterase inhibitors: A review.

    PubMed

    de Souza, Luana G; Rennã, Magdalena N; Figueroa-Villar, Jose D

    2016-07-25

    The first report in literature of the isolation of coumarin was in the year 1820. After this report, other papers were published demonstrating the isolation and synthesis of coumarin and analogues. These compounds have been studying along the years for several different pathologies. One of these pathologies was Alzheimer's disease (AD), being the main cause of dementia in the contemporary world. There are two hypotheses to explain the pathogenesis mechanism and disease symptoms, then having the "amyloid hypothesis" and the "cholinergic hypothesis". Some drugs for AD are based on the theory of "cholinergic hypothesis", which objective is to increase the concentration of ACh in the synaptic cleft by the inhibition of cholinesterases. Over the last twenty years, many studies with coumarins compounds were reported as cholinesterases inhibitors. The aim of the present review is to discuss the studies and development of new compounds for AD treatment. PMID:27174134

  15. Structural investigation of protein kinase C inhibitors

    NASA Technical Reports Server (NTRS)

    Barak, D.; Shibata, M.; Rein, R.

    1991-01-01

    The phospholipid and Ca2+ dependent protein kinase (PKC) plays an essential role in a variety of cellular events. Inhibition of PKC was shown to arrest growth in tumor cell cultures making it a target for possible antitumor therapy. Calphostins are potent inhibitors of PKC with high affinity for the enzyme regulatory site. Structural characteristics of calphostins, which confer the inhibitory activity, are investigated by comparing their optimized structures with the existing models for PKC activation. The resulting model of inhibitory activity assumes interaction with two out of the three electrostatic interaction sites postulated for activators. The model shows two sites of hydrophobic interaction and enables the inhibitory activity of gossypol to be accounted for.

  16. Clinical pharmacokinetics of camptothecin topoisomerase I inhibitors.

    PubMed

    Herben, V M; Ten Bokkel Huinink, W W; Schellens, J H; Beijnen, J H

    1998-08-01

    In this review the clinical pharmacokinetics of camptothecin topoisomerase I inhibitors, an important new class of anticancer drugs, is discussed. Two prototypes, topotecan and irinotecan, are currently marketed in many European countries and the USA for the treatment of patients with ovarian and colorectal cancer, respectively. Other camptothecin derivatives, including lurtotecan, 9-aminocamptothecin (9-AC) and 9-nitrocamptothecin (9-NC), are at different stages of clinical development. The common property of camptothecin analogues is their action against DNA topoisomerase I, but beyond this similarity the compounds differ widely in terms of antitumour efficacy, pharmacology, pharmacokinetics and metabolism. We review chemistry, mechanism of action, stability and bioanalysis of the camptothecins. Dosage and administration, status of clinical application, pharmacokinetics, pharmacodynamics and drug interactions are discussed. PMID:9762728

  17. Pyrophosphate: a key inhibitor of mineralisation.

    PubMed

    Orriss, Isabel R; Arnett, Timothy R; Russell, R Graham G

    2016-06-01

    Inorganic pyrophosphate has long been known as a by-product of many intracellular biosynthetic reactions, and was first identified as a key endogenous inhibitor of biomineralisation in the 1960s. The major source of pyrophosphate appears to be extracellular ATP, which is released from cells in a controlled manner. Once released, ATP can be rapidly hydrolysed by ecto-nucleotide pyrophosphatase/phosphodiesterases to produce pyrophosphate. The main action of pyrophosphate is to directly inhibit hydroxyapatite formation thereby acting as a physiological 'water-softener'. Evidence suggests pyrophosphate may also act as a signalling molecule to influence gene expression and regulate its own production and breakdown. This review will summarise our current understanding of pyrophosphate metabolism and how it regulates bone mineralisation and prevents harmful soft tissue calcification. PMID:27061894

  18. Specific Inhibitors of Ammonia Oxidation in Nitrosomonas

    PubMed Central

    Hooper, Alan B.; Terry, Kathleen R.

    1973-01-01

    The following compounds or treatments have been shown to inhibit the oxidation of ammonia, but not the oxidation of hydroxylamine in cells of Nitrosomonas: (i) metal-binding agents such as allylthiourea or potassium cyanide; (ii) compounds such as SKF 525 which interact with cytochrome P-450 of mammalian microsomes; (iii) carbon monoxide; (iv) inhibitors of catalase, peroxidase, and amine oxidases such as thiosemicarbazide, ethylxanthate, and iproniazid, respectively; (v) uncouplers of oxidative phosphorylation such as m-chlorocarbonylcyanidephenylhydrazone; (vi) electron acceptors such as phenazine methosulfate; (vii) compounds such as methanol or N2O which react with free radicals; and (viii) illumination with 420 lux (5,000 foot candles) of light. PMID:4725614

  19. Tyrosine kinase inhibitors and the thyroid.

    PubMed

    Sherman, Steven I

    2009-12-01

    Protein tyrosine kinase inhibitors (TKIs) have emerged as significant targets for novel cancer therapies. For patients with differentiated or medullary carcinomas unresponsive to conventional treatments, multiple novel therapies primarily targeting angiogenesis have entered clinical trials. Partial response rates up to 30% have been reported in single-agent studies, but prolonged disease stabilisation is more commonly seen. The most successful agents target the vascular endothelial growth factor receptors. Sorafenib and sunitinib have had promising preliminary results reported and are being used selectively for patients who do not qualify for clinical trials. Treatment for patients with metastatic or advanced thyroid carcinoma now emphasises clinical trial opportunities for novel agents with considerable promise. Adverse effects on thyroid function and thyroid hormone metabolism have also been seen with several TKIs, necessitating prospective thyroid function testing for all patients starting therapy. PMID:19942148

  20. Proteinase inhibitor homologues as potassium channel blockers.

    PubMed

    Lancelin, J M; Foray, M F; Poncin, M; Hollecker, M; Marion, D

    1994-04-01

    We report here the NMR structure of dendrotoxin I, a powerful potassium channel blocker from the venom of the African Elapidae snake Dendroaspis polylepis polylepis (black mamba), calculated from an experimentally-derived set of 719 geometric restraints. The backbone of the toxin superimposes on bovine pancreatic trypsin inhibitor (BPTI) with a root-mean-square deviation of < 1.7 A. The surface electrostatic potential calculated for dendrotoxin I and BPTI, reveal an important difference which might account for the differences in function of the two proteins. These proteins may provide examples of adaptation for specific and diverse biological functions while at the same time maintaining the overall three-dimensional structure of a common ancestor. PMID:7544683

  1. Predictive QSAR modeling of phosphodiesterase 4 inhibitors.

    PubMed

    Kovalishyn, Vasyl; Tanchuk, Vsevolod; Charochkina, Larisa; Semenuta, Ivan; Prokopenko, Volodymyr

    2012-02-01

    A series of diverse organic compounds, phosphodiesterase type 4 (PDE-4) inhibitors, have been modeled using a QSAR-based approach. 48 QSAR models were compared by following the same procedure with different combinations of descriptors and machine learning methods. QSAR methodologies used random forests and associative neural networks. The predictive ability of the models was tested through leave-one-out cross-validation, giving a Q² = 0.66-0.78 for regression models and total accuracies Ac=0.85-0.91 for classification models. Predictions for the external evaluation sets obtained accuracies in the range of 0.82-0.88 (for active/inactive classifications) and Q² = 0.62-0.76 for regressions. The method showed itself to be a potential tool for estimation of IC₅₀ of new drug-like candidates at early stages of drug development. PMID:22023934

  2. Identification of pyrazolopyridazinones as PDEδ inhibitors

    PubMed Central

    Papke, Björn; Murarka, Sandip; Vogel, Holger A; Martín-Gago, Pablo; Kovacevic, Marija; Truxius, Dina C; Fansa, Eyad K; Ismail, Shehab; Zimmermann, Gunther; Heinelt, Kaatje; Schultz-Fademrecht, Carsten; Al Saabi, Alaa; Baumann, Matthias; Nussbaumer, Peter; Wittinghofer, Alfred; Waldmann, Herbert; Bastiaens, Philippe I.H.

    2016-01-01

    The prenyl-binding protein PDEδ is crucial for the plasma membrane localization of prenylated Ras. Recently, we have reported that the small-molecule Deltarasin binds to the prenyl-binding pocket of PDEδ, and impairs Ras enrichment at the plasma membrane, thereby affecting the proliferation of KRas-dependent human pancreatic ductal adenocarcinoma cell lines. Here, using structure-based compound design, we have now identified pyrazolopyridazinones as a novel, unrelated chemotype that binds to the prenyl-binding pocket of PDEδ with high affinity, thereby displacing prenylated Ras proteins in cells. Our results show that the new PDEδ inhibitor, named Deltazinone 1, is highly selective, exhibits less unspecific cytotoxicity than the previously reported Deltarasin and demonstrates a high correlation with the phenotypic effect of PDEδ knockdown in a set of human pancreatic cancer cell lines. PMID:27094677

  3. Designing Irreversible Inhibitors--Worth the Effort?

    PubMed

    González-Bello, Concepción

    2016-01-01

    Despite the unquestionable success of numerous irreversible drugs that are currently in clinical use, such as acetylsalicylic acid (Aspirin) and penicillin, the number of such approved drugs is much lower than that of noncovalent drugs. Over the years, the potential off-target effects of these types of compounds have been the primary concern that has hampered their development. However, their remarkable advantages over noncovalent drugs and a better analysis of the risks have decreased the widespread skepticism surrounding them. The design of irreversible inhibitors is a challenge, particularly considering that in some cases their efficacy is due to complex and unexpected mechanisms of action. In this review the main advantages of irreversible inhibition are summarized, and the complexity of certain covalent modification mechanisms is highlighted with selected examples. PMID:26593241

  4. Tumour Angiogenesis and Angiogenic Inhibitors: A Review

    PubMed Central

    Yadav, Lalita; Puri, Naveen; Satpute, Pranali; Sharma, Vandana

    2015-01-01

    Angiogenesis is a complex process depending on the coordination of many regulators and there by activating angiogenic switch. Recent advances in understanding of angiogenic mechanism have lead to the development of several anti-angiogenic and anti-metastatic agents that use the strategy of regulation of angiogenic switch. Antiangiogenic therapy is a form of treatment not cure for cancer and represents a highly effective strategy for destroying tumour because vascular supply is the fundamental requirement for growth of tumour. Because of the quiescent nature of normal adult vasculature, angiogenic inhibitors are expected to confer a degree of specificity when compared to nonspecific modalities of chemo and radiotherapy, so it has the advantage of less toxicities, does not induce drug resistance and deliver a relatively non toxic, long term treatment of tumour. PMID:26266204

  5. Evolution of resistance to quorum sensing inhibitors

    PubMed Central

    Kalia, Vipin C.; Wood, Thomas K.; Kumar, Prasun

    2013-01-01

    The major cause of mortality and morbidity in human beings is bacterial infection. Bacteria have developed resistance to most of the antibiotics primarily due to large scale and “indiscriminate” usage. The need is to develop novel mechanisms to treat bacterial infections. The expression of pathogenicity during bacterial infections is mediated by a cell density dependent phenomenon known as quorum sensing (QS). A wide array of QS systems (QSS) is operative in expressing the virulent behavior of bacterial pathogens. Each QSS may be mediated largely by a few major signals along with others produced in minuscule quantities. Efforts to target signal molecules and their receptors have proved effective in alleviating the virulent behavior of such pathogenic bacteria. These QS inhibitors (QSIs) have been reported to be effective in influencing the pathogenicity without affecting bacterial growth. However, evidence is accumulating that bacteria may develop resistance to QSIs. The big question is whether QSIs will meet the same fate as antibiotics? PMID:24194099

  6. Cyclooxygenase (COX) Inhibitors and the Newborn Kidney

    PubMed Central

    Smith, Francine G.; Wade, Andrew W.; Lewis, Megan L.; Qi, Wei

    2012-01-01

    This review summarizes our current understanding of the role of cyclo-oxygenase inhibitors (COXI) in influencing the structural development as well as the function of the developing kidney. COXI administered either during pregnancy or after birth can influence kidney development including nephronogenesis, and can decrease renal perfusion and ultrafiltration potentially leading to acute kidney injury in the newborn period. To date, which COX isoform (COX-1 or COX-2) plays a more important role in during fetal development and influences kidney function early in life is not known, though evidence points to a predominant role for COX-2. Clinical implications of the use of COXI in pregnancy and in the newborn infant are also evaluated herein, with specific reference to the potential effects of COXI on nephronogenesis as well as newborn kidney function. PMID:24281306

  7. Diazepam binding inhibitor and the endocrine pancreas.

    PubMed

    Ostenson, C G; Ahrén, B; Johansson, O; Karlsson, S; Hilliges, M; Efendic, S

    1991-12-01

    Regulation of blood glucose homeostasis is complex. Its major hormonal regulators include insulin, glucagon and somatostatin from the endocrine pancreas. Secretion of these hormones is controlled predominantly by the supply of nutrients in the circulation but also by nerve signals and other peptides. Thus, it is likely that peptides, released from cells of the gut or endocrine pancreas or from peptidergic nerves, affect glucose homeostasis by modulating the secretion of insulin, glucagon and somatostatin. When searching for novel gut peptides with such effects, diazepam binding inhibitor (DBI) was isolated from the porcine small intestine. By immunocytochemistry, DBI has been demonstrated to occur not only in the gut but also in endocrine cells of the pancreatic islets, namely in the somatostatin-producing D-cells in pig and man, and in the glucagon-producing A-cells in rat. Porcine DBI (pDBI; 10(-8)-10(-7) M) has been shown to suppress glucose-stimulated release of insulin from both isolated islets and perfused pancreas of the rat. Furthermore, secretion of insulin stimulated by either the sulfonylurea glibenclamide or the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX), was inhibited by the peptide. In contrast, arginine-induced release of insulin was unaffected by pDBI. Moreover, pDBI decreased arginine-induced release of glucagon from the perfused rat pancreas, whereas release of somatostatin was unchanged. Notably, rat DBI, structurally identical with rat acyl-CoA-binding protein, has also been demonstrated to inhibit glucose-stimulated release of insulin in the rat, both in vivo and in vitro. Long-term exposure of cultured fetal rat islets to pDBI (10(-8) M) significantly decreased the synthesis of DNA in islet cells.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1780037

  8. Trisubstituted Pyrazolopyrimidines as Novel Angiogenesis Inhibitors

    PubMed Central

    Weitensteiner, Sabine B.; Liebl, Johanna; Krystof, Vladimir; Havlíček, Libor; Gucký, Tomáš; Strnad, Miroslav; Fürst, Robert; Vollmar, Angelika M.; Zahler, Stefan

    2013-01-01

    Current inhibitors of angiogenesis comprise either therapeutic antibodies (e.g. bevacicumab binding to VEGF-A) or small molecular inhibitors of receptor tyrosin kinases like e.g. sunitinib, which inhibits PDGFR and VEGFR. We have recently identified cyclin-dependent kinase 5 (Cdk5) as novel alternative and pharmacologically accessible target in the context of angiogenesis. In the present work we demonstrate that trisubstituted pyrazolo[4,3-d]pyrimidines constitute a novel class of compounds which potently inhibit angiogenesis. All seven tested compounds inhibited endothelial cell proliferation with IC50 values between 1 and 18 µM. Interestingly, this seems not to be due to cytotoxicity, since none of them showed acute cytotoxic effects on endothelial cells at a concentration of 10 µM,. The three most potent compounds (LGR1404, LGR1406 and LGR1407) also inhibited cell migration (by 27, 51 and 31%, resp.), chemotaxis (by 50, 70 and 60% in accumulative distance, resp.), and tube formation (by 25, 60 and 30% of total tube length, resp.) at the non-toxic concentration of 10 µM. Furthermore, angiogenesis was reduced in vivo in the CAM assay by these three compounds. A kinase selectivity profiling revealed that the compounds prevalently inhibit Cdk2, Cdk5 and Cdk9. The phenotype of the migrating cells (reduced formation of lamellipodia, loss of Rac-1 translocation to the membrane) resembles the previously described effects of silencing of Cdk5 in endothelial cells. We conclude that especially LGR1406 and LGR1407 are highly attractive anti-angiogenic compounds, whose effects seem to largely depend on their Cdk5 inhibiting properties. PMID:23336010

  9. A new method for evaluating wax inhibitors and drag reducers

    SciTech Connect

    Hsu, J.J.C.; Brubaker, J.P.

    1995-12-01

    Conventional wax inhibitor evaluation methods such as cold finger and laminar flow loop are not adequate and accurate for evaluating wax inhibitors to be used in a wide operating temperature range and flow regimes such as North Sea subsea transport pipelines. A new method has been developed to simultaneously measure fluid rheology change and wax inhibition and to evaluate wax inhibitors or drag reducers at the field operating conditions. Selection criteria have been defined to search for an effective wax inhibitor. The criteria ensure the chemical selected is the most effective one for the specific oil and flow conditions. The operation cost savings by this accurate method is significant. Nine chemical companies joined the project of finding an wax inhibitor for a North Sea prospect. More than twenty wax inhibitors have been tested and evaluated with this new method for several waxy oil fields. The new method provides data of fluid rheology, war deposition rates and wax inhibition in the operating temperature range, overall average wax inhibition and degree of fluid flow improvement. These data are important to evaluate a wax inhibitor or drag reducer. Most of the wax inhibitors tested have good wax inhibition at high temperatures, but not many chemicals work well at low temperatures. The chemical tested may improved fluid flow behavior at low temperature but not wax deposition. Drag reducers tested did not work well at North Sea seabed temperature.

  10. A low molecular weight proteinase inhibitor produced by T lymphocytes.

    PubMed Central

    Ganea, D; Teodorescu, M; Dray, S

    1986-01-01

    A low molecular weight (MW) proteinase inhibitor, between 6500 and 21,500 MW, appeared in the supernatant of rabbit spleen cells cultured at high density for 24 hr. The inhibitor inhibited the enzymatic activity of trypsin for both a high MW natural substrate, fibrinogen, and for a low MW artificial substrate, Chromozym TRY. The low MW proteinase inhibitor is protein in nature and is different, in terms of specificity for enzymes, MW and sensitivity to different physical or chemical treatments, from aprotinin, a low MW proteinase inhibitor (6500 MW) of bovine origin, and from the soybean trypsin inhibitor, a relatively high MW proteinase inhibitor (21,500 MW). The inhibitor was found in the supernatant of purified T cells but not B cells, and its production was increased in the presence of an optimal concentration of Con A. The possibility that this proteinase inhibitor has a role in the regulation of trypsin-like proteinases involved to the immune response remains to be investigated. Images Figure 4 PMID:2417942

  11. Role of Protease-Inhibitors in Ocular Diseases.

    PubMed

    Pescosolido, Nicola; Barbato, Andrea; Pascarella, Antonia; Giannotti, Rossella; Genzano, Martina; Nebbioso, Marcella

    2014-01-01

    It has been demonstrated that the balance between proteases and protease-inhibitors system plays a key role in maintaining cellular and tissue homeostasis. Indeed, its alteration has been involved in many ocular and systemic diseases. In particular, research has focused on keratoconus, corneal wounds and ulcers, keratitis, endophthalmitis, age-related macular degeneration, Sorsby fundus dystrophy, loss of nerve cells and photoreceptors during optic neuritis both in vivo and in vitro models. Protease-inhibitors have been extensively studied, rather than proteases, because they may represent a therapeutic approach for some ocular diseases. The protease-inhibitors mainly involved in the onset of the above-mentioned ocular pathologies are: α2-macroglobulin, α1-proteinase inhibitor (α1-PI), metalloproteinase inhibitor (TIMP), maspin, SERPINA3K, SERPINB13, secretory leukocyte protease inhibitor (SLPI), and calpeptin. This review is focused on the several characteristics of dysregulation of this system and, particularly, on a possible role of proteases and protease-inhibitors in molecular remodeling that may lead to some ocular diseases. Recently, researchers have even hypothesized a possible therapeutic effect of the protease-inhibitors in the treatment of injured eye in animal models. PMID:25493637

  12. Detecting and treating breast cancer resistance to EGFR inhibitors

    DOEpatents

    Moonlee, Sun-Young; Bissell, Mina J.; Furuta, Saori; Meier, Roland; Kenny, Paraic A.

    2016-04-05

    The application describes therapeutic compositions and methods for treating cancer. For example, therapeutic compositions and methods related to inhibition of FAM83A (family with sequence similarity 83) are provided. The application also describes methods for diagnosing cancer resistance to EGFR inhibitors. For example, a method of diagnosing cancer resistance to EGFR inhibitors by detecting increased FAM83A levels is described.

  13. New-onset toxicity with programmed death-1 inhibitor rechallenge.

    PubMed

    Ludlow, Steven P; Andrews, Stephanie; Pasikhova, Yanina; Hill, Eboné

    2016-06-01

    Immunotherapy has become a mainstay in the treatment of metastatic melanoma. Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) inhibitors and programmed death-1 (PD-1) inhibitors, which have been added more recently, represent two of the main classes of immunomodulating agents. PD-1 inhibitors are well tolerated and are known to have a decreased rate of occurrence of adverse effects compared with CTLA-4 inhibitors. However, the risk remains for serious immune-mediated adverse reactions. Given their long half and extended efficacy, treatment with a CTLA-4 inhibitor before use of a PD-1 inhibitor may increase the risk of adverse effects. In addition, caution should be exercised when rechallenging grade 3 or 4 adverse effects with the same agent or a different agent of the same class. The re-emergence of a previous toxicity may occur or, as found in this case, a new severe effect may arise. This article will present a case of fatal immune-related hepatoxicity in a patient treated with a CTLA-4 inhibitor, followed by treatment with a PD-1 inhibitor. The mechanisms of action and safety profiles for both classes of drugs will also be reviewed. PMID:26983078

  14. Submicromolar Phosphinic Inhibitors of E. coli Aspartate Transcarbamoylase

    PubMed Central

    Coudray, Laëtitia; Kantrowitz, Evan R.; Montchamp, Jean-Luc

    2009-01-01

    The design, syntheses, and enzymatic activity of two submicromolar competitive inhibitors of aspartate transcarbamoylase (ATCase) are described. The phosphinate inhibitors are analogs of N-phosphonacetyl-L-aspartate (PALA) but have a reduced charge at the phosphorus moiety. The mechanistic implications are discussed in terms of a possible cyclic transition-state during enzymatic catalysis. PMID:19097895

  15. Discovery – Targeted Treatments and mTOR Inhibitors

    Cancer.gov

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

  16. MEK1/2 Inhibitors: Molecular Activity and Resistance Mechanisms.

    PubMed

    Wu, Pui-Kei; Park, Jong-In

    2015-12-01

    Aberrant activation of the three-layered protein kinase cascade, Raf/MEK/ERK, is often detected in human cancer, which is mainly attributed to the oncogenic alterations of RAF, or its upstream activators RAS or cell surface receptor tyrosine kinases. Deregulated activity of the Raf/MEK/ERK pathway drives uncontrolled tumor cell proliferation and survival, thus providing a rational therapeutic target for the treatment of many cancers. While Raf, MEK1/2, and ERK1/2 are equally important targets for the design of therapeutic small molecular weight inhibitors, the effort to develop MEK1/2-specific inhibitors has been greatly successful. Particularly, MEK1/2 have been relatively advantageous for the design of highly selective adenosine triphosphate (ATP)-noncompetitive inhibitors. Indeed, a plethora of highly selective and potent MEK1/2 inhibitors are now available and many of those inhibitors have been evaluated for their therapeutic potential. Herein, we review different MEK1/2 inhibitors that have been studied for their inhibitory mechanisms and therapeutic potential in cancer. Some of the key structural features of MEK1/2 that are important for the efficacy of these inhibitors are also discussed. In addition, we discuss current challenges and future prospective in using these advanced MEK1/2 inhibitors for cancer therapy. PMID:26615130

  17. Heart failure: SGLT2 inhibitors and heart failure -- clinical implications.

    PubMed

    Raz, Itamar; Cahn, Avivit

    2016-04-01

    The latest findings from the EMPA-REG OUTCOME trial show a 34% reduction in hospitalization for heart failure or cardiovascular death in patients receiving empagliflozin, a sodium/glucose cotransporter 2 (SGLT2) inhibitor, compared with placebo. These outstanding results call for discussion of the clinical implications, and in-depth studies of the mechanisms of action of SGLT2 inhibitors. PMID:26961066

  18. Aminopiperidine-Fused Imidazoles as Dipeptidyl Peptidase-IV Inhibitors

    SciTech Connect

    Edmondson, S.; Mastracchio, A; Cox, J; Eiermann, G; He, H; Lyons, K; Patel, R; Patel, S; Petrov, A; et. al.

    2009-01-01

    A new series of DPP-4 inhibitors derived from piperidine-fused benzimidazoles and imidazopyridines is described. Optimization of this class of DPP-4 inhibitors led to the discovery of imidazopyridine 34. The potency, selectivity, cross-species DMPK profiles, and in vivo efficacy of 34 is reported.

  19. Corrosion inhibitors for solar-heating and cooling

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1979-01-01

    Report describes results of tests conducted to evaluate abilities of 12 candidate corrosion inhibitors to protect aluminum, steel, copper, or stainless steel at typical conditions encountered in solar heating and cooling systems. Inhibitors are based on sodium salts including nitrates, borates, silicates, and phosphates.

  20. Peptidyl-urea based inhibitors of soluble epoxide hydrolases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We prepared a series of amino acid derived cyclohexyl and adamantyl ureas and tested them as inhibitors of the human soluble epoxide hydrolase, and obtained very potent compounds (K(I)=15nM) that are >10-fold more soluble than previously described sEH inhibitors. While our lead compound 2 showed low...

  1. Replacement inhibitors for tank farm cooling coil systems

    SciTech Connect

    Hsu, T.C.

    1995-03-23

    Sodium chromate has been an effective corrosion inhibitor for the cooling coil systems in Savannah River Site (SRS) waste tanks for over 40 years. Due to their age and operating history, cooling coils occasionally fail allowing chromate water to leak into the environment. When the leaks spill 10 lbs. or more of sodium chromate over a 24-hr period, the leak incidents are classified as Unusual Occurrences (UO) per CERCLA (Comprehensive Environmental Response, Compensation and Liability Act). The cost of reporting and cleaning up chromate spills prompted High Level Waste Engineering (HLWE) to initiate a study to investigate alternative tank cooling water inhibitor systems and the associated cost of replacement. Several inhibitor systems were investigated as potential alternatives to sodium chromate. All would have a lesser regulatory impact, if a spill occurred. However, the conversion cost is estimated to be $8.5 million over a period of 8 to 12 months to convert all 5 cooling systems. Although each of the alternative inhibitors examined is effective in preventing corrosion, there is no inhibitor identified that is as effective as chromate. Assuming 3 major leaks a year (the average over the past several years), the cost of maintaining the existing inhibitor was estimated at $0.5 million per year. Since there is no economic or regulatory incentive to replace the sodium chromate with an alternate inhibitor, HLWE recommends that sodium chromate continue to be used as the inhibitor for the waste tank cooling systems.

  2. Identification of a New Class of Nonpeptidic Inhibitors of Cruzain

    PubMed Central

    Brak, Katrien; Doyle, Patricia S.; McKerrow, James H.; Ellman, Jonathan A.

    2009-01-01

    Cruzain is the major cysteine protease of T. cruzi, which is the causative agent of Chagas’ disease and is a promising target for the development of new chemotherapy. With the goal of developing potent nonpeptidic inhibitors of cruzain, the Substrate Activity Screening (SAS) method was used to screen a library of protease substrates initially designed to target the homologous human protease cathepsin S. Structure-based design was next used to further improve substrate cleavage efficiency by introducing additional binding interactions in the S3 pocket of cruzain. The optimized substrates were then converted to inhibitors by the introduction of cysteine protease mechanism-based pharmacophores. Inhibitor 38 was determined to be reversible even though it incorporated the vinyl sulfone pharmacophore that is well documented to give irreversible cruzain inhibition for peptidic inhibitors. The previously unexplored β-chloro vinyl sulfone pharmacophore provided mechanistic insight that led to the development of potent irreversible acyl- and aryl-oxymethyl ketone cruzain inhibitors. For these inhibitors, potency did not solely depend on leaving group pKa, with 2,3,5,6-tetrafluorophenoxymethyl ketone 54 identified as one of the most potent inhibitors with a second order inactivation constant of 147,000 s−1M−1. This inhibitor completely eradicated the T. cruzi parasite from mammalian cell cultures and consequently has the potential to lead to new chemotherapeutics for Chagas’ disease. PMID:18435536

  3. BRAF inhibitors in colorectal cancer: Toward a differentiation therapy?

    PubMed

    Herr, Ricarda; Brummer, Tilman

    2015-01-01

    BRAF inhibitor monotherapy appears to be ineffective in BRAF (V600E)-positive colorectal cancer (CRC) as a result of inherent EGFR-mediated resistance mechanisms. This concept initiated combinatorial treatment approaches. Nevertheless, BRAF inhibition in isogenic CRC cell lines induced enhanced cell-cell adhesion and differentiation, underlining a potential benefit of BRAF inhibitors in CRC. PMID:27308494

  4. Rational design of an organometallic glutathione transferase inhibitor

    SciTech Connect

    Ang, W.H.; Parker, L.J.; De Luca, A.; Juillerat-Jeanneret, L.; Morton, C.J.; LoBello, M.; Parker, M.W.; Dyson, P.J.

    2010-08-17

    A hybrid organic-inorganic (organometallic) inhibitor was designed to target glutathione transferases. The metal center is used to direct protein binding, while the organic moiety acts as the active-site inhibitor. The mechanism of inhibition was studied using a range of biophysical and biochemical methods.

  5. Small Molecule Inhibitors of Anthrax Lethal Factor Toxin

    PubMed Central

    Williams, John D.; Khan, Atiyya R.; Cardinale, Steven C.; Butler, Michelle M.; Bowlin, Terry L.; Peet, Norton P.

    2014-01-01

    This manuscript describes the preparation of new small molecule inhibitors of Bacillus anthracis lethal factor. Our starting point was the symmetrical, bis-quinolinyl compound 1 (NSC 12155). Optimization of one half of this molecule led to new LF inhibitors that were desymmetrized to afford more drug-like compounds. PMID:24290062

  6. Hydroxyapatite microparticles as feedback-active reservoirs of corrosion inhibitors.

    PubMed

    Snihirova, D; Lamaka, S V; Taryba, M; Salak, A N; Kallip, S; Zheludkevich, M L; Ferreira, M G S; Montemor, M F

    2010-11-01

    This work contributes to the development of new feedback-active anticorrosion systems. Inhibitor-doped hydroxyapatite microparticles (HAP) are used as reservoirs, storing corrosion inhibitor to be released on demand. Release of the entrapped inhibitor is triggered by redox reactions associated with the corrosion process. HAP were used as reservoirs for several inhibiting species: cerium(III), lanthanum(III), salicylaldoxime, and 8-hydroxyquinoline. These species are effective corrosion inhibitors for a 2024 aluminum alloy (AA2024), used here as a model metallic substrate. Dissolution of the microparticles and release of the inhibitor are triggered by local acidification resulting from the anodic half-reaction during corrosion of AA2024. Calculated values and experimentally measured local acidification over the aluminum anode (down to pH = 3.65) are presented. The anticorrosion properties of inhibitor-doped HAP were assessed using electrochemical impedance spectroscopy. The microparticles impregnated with the corrosion inhibitors were introduced into a hybrid silica-zirconia sol-gel film, acting as a thin protective coating for AA2024, an alloy used for aeronautical applications. The protective properties of the sol-gel films were improved by the addition of HAP, proving their applicability as submicrometer-sized reservoirs of corrosion inhibitors for active anticorrosion coatings. PMID:20942404

  7. Discovery, Design, and Optimization of Isoxazole Azepine BET Inhibitors.

    PubMed

    Gehling, Victor S; Hewitt, Michael C; Vaswani, Rishi G; Leblanc, Yves; Côté, Alexandre; Nasveschuk, Christopher G; Taylor, Alexander M; Harmange, Jean-Christophe; Audia, James E; Pardo, Eneida; Joshi, Shivangi; Sandy, Peter; Mertz, Jennifer A; Sims, Robert J; Bergeron, Louise; Bryant, Barbara M; Bellon, Steve; Poy, Florence; Jayaram, Hariharan; Sankaranarayanan, Ravichandran; Yellapantula, Sreegouri; Bangalore Srinivasamurthy, Nandana; Birudukota, Swarnakumari; Albrecht, Brian K

    2013-09-12

    The identification of a novel series of small molecule BET inhibitors is described. Using crystallographic binding modes of an amino-isoxazole fragment and known BET inhibitors, a structure-based drug design effort lead to a novel isoxazole azepine scaffold. This scaffold showed good potency in biochemical and cellular assays and oral activity in an in vivo model of BET inhibition. PMID:24900758

  8. Bioabatement with xylanase supplementation to reduce enzymatic hydrolysis inhibitors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioabatement, using the fungus Coniochaeta ligniaria NRRL30616 can effectively eliminate enzyme inhibitors from pretreated biomass hydrolysis. However, our recent research suggested that bioabatement had no beneficial effect on removing xylo-oligomers which were identified as strong inhibitors to ce...

  9. Electrochemical corrosion testing: An effective tool for corrosion inhibitor evaluation

    SciTech Connect

    Bartley, L.S.; Van de Ven, P.; Mowlem, J.K.

    1996-10-01

    Corrosivity of an Antifreeze/Coolant can lead to localized attacks which are a major cause for metal failure. To prevent this phenomenon, specific corrosion inhibitors are used to protect the different metals in service. This paper will discuss the electrochemical principles behind corrosion, Realized corrosion and corrosion inhibition. It will also discuss electrochemical techniques which allow for the evaluation of these inhibitors.

  10. Compatibility of a corrosion inhibitor with gas sweetening agents

    SciTech Connect

    Ramkez, M.; Morales, J.L.; Afonso, M.E.; Viloria, A.

    1998-12-31

    A methodology to establish the effect of a corrosion inhibitor on the behavior of two gas sweetening agents namely an amine (A) and a solid product constituted by iron oxides (B), has been developed. This information will be useful in case of traces of inhibitor passing through these two sweetening systems. Tests conducted in a static autoclave tester in gas sweetening conditions were made to determine the sour gas absorption power of the two agents, A and B, in presence or absence of inhibitor. Additionally, the effect of the inhibitor on the foaming power of agent A was evaluated, at room conditions. According to the results obtained, in the range of conditions considered in this study, neither does the inhibitor affect the sour gas absorption power nor the foaming power of agent A. Nevertheless, the anticorrosive product diminished by 12.5% the sour gas removal capability of agent B.

  11. Corrosion inhibitor film formation studied by ATR-FTIR

    SciTech Connect

    Campbell, S.; Jovancicevic, V.

    1999-11-01

    The development of an inhibitor film is essential for the effective performance of a corrosion inhibitor. The use of attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) allows the development of inhibitor films on iron oxides to be monitored. For two distinct corrosion inhibitor chemistries, oleic imidazoline and phosphate ester, the film formation and corrosion processes are monitored on Fe{sub 3}O{sub 4} in a powdered form (a model surface). Additional data following on the physical and chemical properties are obtained using XPS and SEM techniques, which allows for a more complete characterization of the model inhibitor/oxide system. By the proper choice of system and measurement techniques, the complex phenomenon of corrosion inhibition may be analyzed directly.

  12. Characterization of Encapsulated Corrosion Inhibitors for Environmentally Friendly Smart Coatings

    NASA Technical Reports Server (NTRS)

    Pearman, Benjamin Pieter; Li, Wenyan; Buhrow, Jerry; Zhang, Xuejun; Surma, Jan; Fitzpatrick, Lilly; Montgomery, Eliza; Calle, Luz Marina

    2014-01-01

    Research efforts are under way to replace current corrosion inhibitors with more environmentally friendly alternatives. However, problems with corrosion inhibition efficiency, coating compatibility and solubility have hindered the use of many of these materials as simple pigment additives.This paper will present technical details on how the Corrosion Technology Lab at NASAs Kennedy Space Center (KSC) has addressed these issues by encapsulating environmentally friendly inhibitors into organic and inorganic microparticles and microcapsules. The synthetic process for polymer particles was characterized and post-synthesis analysis was performed to determine the interactions between the inhibitors and the encapsulation material. The pH-controlled release of inhibitors from various particle formulations in aqueous base was monitored and compared to both electrochemical and salt immersion accelerated corrosion experiment. Furthermore, synergistic corrosion inhibition effects observed during the corrosion testing of several inhibitor combinations will be presented.

  13. Development of nitrile-based peptidic inhibitors of cysteine cathepsins.

    PubMed

    Frizler, Maxim; Stirnberg, Marit; Sisay, Mihiret Tekeste; Gütschow, Michael

    2010-01-01

    It is now becoming clear that several papain-like cysteine cathepsins are involved in the pathophysiology of diseases such as osteoporosis, autoimmune disorders, and cancer. Therefore, the development of potent and selective cathepsin inhibitors is an attractive subject for medicinal chemists. New advances have been made for nitrile-based inhibitors, leading to the identification of the cathepsin K inhibitor odanacatib and other candidates with potential for therapeutic use. This review summarizes the development of peptidic and peptidomimetic compounds with an electrophilic nitrile 'warhead' as inhibitors of the cysteine cathepsins B, S, L, C, and K. Peptide nitriles have been shown to reversibly react with the active site cysteine under formation of a covalent thioimidate adduct. The structural optimization with respect to the positions P3, P2, P1, P1', and P2' resulted in the identification of potent and selective inhibitors of the corresponding cathepsins. The underlying structure-activity relationships are discussed herein. PMID:20166952

  14. Suppression of caspase-11 expression by histone deacetylase inhibitors

    SciTech Connect

    Heo, Hyejung; Yoo, Lang; Shin, Ki Soon; Kang, Shin Jung

    2009-01-02

    It has been well documented that histone deacetylase inhibitors suppress inflammatory gene expression. Therefore, we investigated whether histone deacetylase inhibitors modulate the expression of caspase-11 that is known as an inducible caspase regulating both inflammation and apoptosis. In the present study, we show that sodium butyrate and trichostatin A, two structurally unrelated inhibitors of histone deacetylase (HDAC), effectively suppressed the induction of caspase-11 in mouse embryonic fibroblasts stimulated with lipopolysaccharides. Sodium butyrate inhibited the activation of upstream signaling events for the caspase-11 induction such as activation of p38 mitogen-activated protein kinase and c-Jun N-terminal kinase, degradation of inhibitor of {kappa}B, and activation of nuclear factor-{kappa}B. These results suggest that the HDAC inhibitor suppressed cytosolic signaling events for the induction of caspase-11 by inhibiting the deacetylation of non-histone proteins.

  15. Recent advances in the development of sphingosine kinase inhibitors.

    PubMed

    Pitman, Melissa R; Costabile, Maurizio; Pitson, Stuart M

    2016-09-01

    Sphingosine kinase (SK) 1 and 2 are lipid kinases that catalyse the formation of sphingosine 1-phosphate (S1P), a potent signalling molecule with a wide array of cellular effects. SK1 and 2 have been shown to be up-regulated in tumours and their genetic ablation or inhibition has been shown to slow tumour growth as well as sensitise cancer cells to chemotherapeutics. The SKs have been extensively studied, with a plethora of inhibitors developed that target the sphingosine-binding pocket of the enzyme, some with nanomolar affinities. Recently, inhibitors targeting the ATP pocket of SK have also been described. Here we discuss the development of these new small molecule SK inhibitors, summarise the recent discovery of off-targets effects of many current SK inhibitors, and provide an overview of the usefulness of these inhibitors as in vitro tools and therapeutic agents. PMID:27297359

  16. Novel Plasminogen Activator Inhibitor-1 Inhibitors Prevent Diabetic Kidney Injury in a Mouse Model

    PubMed Central

    Park, Jong Hee; Lee, Jung Hwa; Lee, Hi Bahl; Miyata, Toshio; Ha, Hunjoo

    2016-01-01

    Diabetic nephropathy is the leading cause of end-stage renal disease worldwide, but no effective therapeutic strategy is available. Because plasminogen activator inhibitor-1 (PAI-1) is increasingly recognized as a key factor in extracellular matrix (ECM) accumulation in diabetic nephropathy, this study examined the renoprotective effects of TM5275 and TM5441, two novel orally active PAI-1 inhibitors that do not trigger bleeding episodes, in streptozotocin (STZ)-induced diabetic mice. TM5275 (50 mg/kg) and TM5441 (10 mg/kg) were administered orally for 16 weeks to STZ-induced diabetic and age-matched control mice. Relative to the control mice, the diabetic mice showed significantly increased (p < 0.05) plasma glucose and creatinine levels, urinary albumin excretion, kidney-to-bodyweight ratios, glomerular volume, and fractional mesangial area. Markers of fibrosis and inflammation along with PAI-1 were also upregulated in the kidney of diabetic mice, and treatment with TM5275 and TM5441 effectively inhibited albuminuria, mesangial expansion, ECM accumulation, and macrophage infiltration in diabetic kidneys. Furthermore, in mouse proximal tubular epithelial (mProx24) cells, both TM5275 and TM5441 effectively inhibited PAI-1-induced mRNA expression of fibrosis and inflammation markers and also reversed PAI-1-induced inhibition of plasmin activity, which confirmed the efficacy of the TM compounds as PAI-1 inhibitors. These data suggest that TM compounds could be used to prevent diabetic kidney injury. PMID:27258009

  17. Specificity of a protein phosphatase inhibitor from rabbit skeletal muscle.

    PubMed Central

    Cohen, P; Nimmo, G A; Antoniw, J F

    1977-01-01

    A hear-stable protein, which is a specific inhibitor of protein phosphatase-III, was purified 700-fold from skeletal muscle by a procedure that involved heat-treatment at 95 degrees C, chromatography on DEAE-cellulose and gel filtration on Sephadex G-100. The final step completely resolved the protein phosphatase inhibitor from the protein inhibitor of cyclic AMP-dependent protein kinase. The phosphorylase phosphatase, beta-phosphorylase kinase phosphatase, glycogen synthase phosphatase-1 and glycogen synthase phosphatase-2 activities of protein phosphatase-III [Antoniw, J. F., Nimmo, H. G., Yeaman, S. J. & Cohen, P.(1977) Biochem.J. 162, 423-433] were inhibited in a very similar manner by the protein phosphatase inhibitor and at least 95% inhibition was observed at high concentrations of inhibitor. The two forms of protein phosphatase-III, termed IIIA and IIIB, were equally susceptible to the protein phosphatase inhibitor. The protein phosphatase inhibitor was at least 200 times less effective in inhibiting the activity of protein phosphatase-I and protein phosphatase-II. The high degree of specificity of the inhibitor for protein phosphatase-III was used to show that 90% of the phosphorylase phosphatase and glycogen synthase phosphatase activities measured in muscle extracts are catalysed by protein phosphatase-III. Protein phosphatase-III was tightly associated with the protein-glycogen complex that can be isolated from skeletal muscle, whereas the protein phosphatase inhibitor and protein phosphatase-II were not. The results provide further evidence that the enzyme that catalyses the dephosphorylation of the alpha-subunit of phosphorylase kinase (protein phosphatase-II) and the enzyme that catalyses the dephosphorylation of the beta-subunit of phosphorylase kinase (protein phosphatase-III) are distinct. The results suggest that the protein phosphatase inhibitor may be a useful probe for differentiating different classes of protein phosphatases in mammalian

  18. The primary inhibitor of plasmin in human plasma.

    PubMed Central

    Müllertz, S; Clemmensen, I

    1976-01-01

    A complex between plasmin and an inhibitor was isolated by affinity chromatography from urokinase-activated human plasma. The complex did not react with antibodies against any of the known proteinase inhibitors in plasma. A rabbit antiserum against the complex was produced. It contained antibodies agianst plasminogen+plasmin and an alpha2 protein. By crossed immunoelectrophoresis the alpha2 protein was shown to form a complex with plasmin, when generated by urokinase in plasma, and with purified plasmin. The alpha2 protein was eluted by Sephadex G-200 gel filtration with KD approx. 0.35, different from the other inhibitors of plasmin in plasma, and corresponding to an apparent relative molecular mass (Mr) of about 75000. By sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the Mr of the complex was found to be approx. 130000. After reduction of the complex two main bands of protein were observed, with Mr, about 72000 and 66000, probably representing an acyl-enzyme complex of plasmin-light chain and inhibitor-heavy chain, and a plasmin-heavy chain. A weak band with Mr 9000 was possibly an inhibitor-light chain. The inhibitor was partially purified and used to titrate purified plasmin of known active-site concentration. The inhibitor bound plasmin rapidly and strongly. Assuming an equimolar combining ratio, the concentration of active inhibitor in normal human plasma was estimated to be 1.1 mumol/1. A fraction about 0.3 of the antigenic inhibitor protein appeared to be functionally inactive. In plasma, plasmin is primarily bound to the inhibitor. Only after its saturation does lysis of fibrinogen and fibrin occur and a complex between plasmin and alpha2 macroglobulin appear. Images PLATE 1 PLATE 2 PLATE 3 PLATE 4 PMID:137718

  19. Repurposing human PDE4 inhibitors for neglected tropical diseases. Evaluation of analogs of the human PDE4 inhibitor GSK-256066 as inhibitors of PDEB1 of Trypanosoma brucei

    PubMed Central

    Ochiana, Stefan O.; Bland, Nicholas D.; Settimo, Luca; Campbell, Robert K.; Pollastri, Michael P.

    2014-01-01

    Cyclic nucleotide phosphodiesterases (PDEs) have been identified as important enzyme targets for drug development in both humans and in Trypanosoma brucei, the causative agent of human African trypanosomiasis (HAT). With this in mind, we recently reported the profiling of a range of human PDE inhibitors, showing that human PDE4 (hPDE4) inhibitors tend to display the best potency against the trypanosomal phosphodiesterase TbrPDEB1. Among these was GSK-256066, a potent inhibitor of hPDE4 and a weak inhibitor of TbrPDEB1. In this report, we describe the results of a structure-activity relationship study of this chemotype, leading to the discovery of analogs with improved potency against TbrPDEB1 and micromolar inhibition of T. brucei cellular growth. We rationalize the potency trends via molecular docking of the new inhibitors into a recently reported apo structure of TbrPDEB1. The studies in this article will inform future efforts in repurposing human PDE inhibitors as anti-trypanosomal agents. PMID:25283372

  20. Repurposing human PDE4 inhibitors for neglected tropical diseases. Evaluation of analogs of the human PDE4 inhibitor GSK-256066 as inhibitors of PDEB1 of Trypanosoma brucei.

    PubMed

    Ochiana, Stefan O; Bland, Nicholas D; Settimo, Luca; Campbell, Robert K; Pollastri, Michael P

    2015-05-01

    Cyclic nucleotide phosphodiesterases (PDEs) have been identified as important enzyme targets for drug development in both humans and Trypanosoma brucei, the causative agent of human African trypanosomiasis. With this in mind, we recently reported the profiling of a range of human phosphodiesterase inhibitors, showing that human PDE4 inhibitors tend to display the best potency against the trypanosomal phosphodiesterase TbrPDEB1. Among these was GSK-256066, a potent inhibitor of human PDE4 and a weak inhibitor of TbrPDEB1. In this report, we describe the results of a structure-activity relationship study of this chemotype, leading to the discovery of analogs with improved potency against TbrPDEB1 and micromolar inhibition of T. brucei cellular growth. We rationalize the potency trends via molecular docking of the new inhibitors into a recently reported apo structure of TbrPDEB1. The studies in this article will inform future efforts in repurposing human PDE inhibitors as antitrypanosomal agents. PMID:25283372

  1. mTOR kinase inhibitors synergize with histone deacetylase inhibitors to kill B-cell acute lymphoblastic leukemia cells.

    PubMed

    Beagle, Brandon R; Nguyen, Duc M; Mallya, Sharmila; Tang, Sarah S; Lu, Mengrou; Zeng, Zhihong; Konopleva, Marina; Vo, Thanh-Trang; Fruman, David A

    2015-02-10

    High activity of the mechanistic target of rapamycin (mTOR) is associated with poor prognosis in pre-B-cell acute lymphoblastic leukemia (B-ALL), suggesting that inhibiting mTOR might be clinically useful. However, emerging data indicate that mTOR inhibitors are most effective when combined with other target agents. One strategy is to combine with histone deacetylase (HDAC) inhibitors, since B-ALL is often characterized by epigenetic changes that silence the expression of pro-apoptotic factors. Here we tested combinations of mTOR and pan-HDAC inhibitors on B-ALL cells, including both Philadelphia chromosome-positive (Ph+) and non-Ph cell lines. We found that mTOR kinase inhibitors (TOR-KIs) synergize with HDAC inhibitors to cause apoptosis in B-ALL cells and the effect is greater when compared to rapamycin plus HDAC inhibitors. The combination of TOR-KIs with the clinically approved HDAC inhibitor vorinostat increased apoptosis in primary pediatric B-ALL cells in vitro. Mechanistically, TOR-KI and HDAC inhibitor combinations increased expression of pro-death genes, including targets of the Forkhead Box O (FOXO) transcription factors, and increased sensitivity to apoptotic triggers at the mitochondria. These findings suggest that targeting epigenetic factors can unmask the cytotoxic potential of TOR-KIs towards B-ALL cells. PMID:25576920

  2. Synergistic inhibitor binding to the papain-like protease of human SARS coronavirus: mechanistic and inhibitor design implications.

    PubMed

    Lee, Hyun; Cao, Shuyi; Hevener, Kirk E; Truong, Lena; Gatuz, Joseph L; Patel, Kavankumar; Ghosh, Arun K; Johnson, Michael E

    2013-08-01

    We previously developed two potent chemical classes that inhibit the essential papain-like protease (PLpro) of severe acute respiratory syndrome coronavirus. In this study, we applied a novel approach to identify small fragments that act synergistically with these inhibitors. A fragment library was screened in combination with four previously developed lead inhibitors by fluorescence-based enzymatic assays. Several fragment compounds synergistically enhanced the inhibitory activity of the lead inhibitors by approximately an order of magnitude. Surface plasmon resonance measurements showed that three fragments bind specifically to the PLpro enzyme. Mode of inhibition, computational solvent mapping, and molecular docking studies suggest that these fragments bind adjacent to the binding site of the lead inhibitors and further stabilize the inhibitor-bound state. We propose potential next-generation compounds based on a computational fragment-merging approach. This approach provides an alternative strategy for lead optimization for cases in which direct co-crystallization is difficult. PMID:23788528

  3. Synergistic Inhibitor Binding to the Papain-Like Protease of Human SARS Coronavirus – Mechanistic and Inhibitor Design Implications

    PubMed Central

    Lee, Hyun; Cao, Shuyi; Hevener, Kirk E.; Truong, Lena; Gatuz, Joseph L.; Patel, Kavankumar; Ghosh, Arun K.; Johnson, Michael E.

    2014-01-01

    We have previously developed two potent chemical classes that inhibit the essential papain-like protease (PLpro) of severe acute respiratory syndrome coronavirus (SARS-CoV). In this study, we applied a novel approach to identify small fragments that act synergistically with these inhibitors. A fragment library was screened in combination with four previously developed lead inhibitors by fluorescence-based enzymatic assays. Several fragment compounds synergistically enhanced the inhibitory activity of the lead inhibitors by approximately an order of magnitude. Surface plasmon resonance (SPR) measurements showed that three fragments bind specifically to the PLpro enzyme. Mode of inhibition, computational solvent mapping, and molecular docking studies suggest that these fragments bind adjacent to the binding site of the lead inhibitors and further stabilize the inhibitor-bound state. We propose potential next generation compounds based upon a computational, fragment-merging approach. This approach provides an alternative strategy for lead optimization in cases where direct co-crystallization is difficult. PMID:23788528

  4. Assessing the emetic potential of PDE4 inhibitors in rats

    PubMed Central

    Robichaud, A; Savoie, C; Stamatiou, P B; Lachance, N; Jolicoeur, P; Rasori, R; Chan, C C

    2002-01-01

    Type 4 phosphodiesterase (PDE4) inhibitors mimic the pharmacological actions of alpha2-adrenoceptor antagonists. This has been postulated as the mechanism by which PDE4 inhibitors induce emesis and was also demonstrated by their ability to reverse xylazine/ketamine-induced anaesthesia. We further characterized this latter effect since it appears to reflect the emetic potential of PDE4 inhibitors.Selective inhibitors of PDE 1, 2, 3, 4 and 5 were studied in rats, on the duration of anaesthesia induced by the combination of xylazine (10 mg kg−1, i.m.) and ketamine (10 mg kg−1, i.m.) PMNPQ (i.e. 6-(4-pyridylmethyl)-8-(3-nitrophenyl)quinoline)  –  PDE4 inhibitor: 0.01 – 3 mg kg−1), like MK-912 (alpha2-adrenoceptor antagonist: 0.01 – 3 mg kg−1), dose-dependently reduced the duration of anaesthesia. In contrast, vinpocetine (PDE1 inhibitor), EHNA (PDE2 inhibitor), milrinone (PDE3 inhibitor) and zaprinast (PDE5 inhibitor) had no significant effect at the doses tested (1 – 10 mg kg−1). Analysis of plasma and cerebrospinal fluid (CSF) of treated animals confirmed the absorption and distribution to the brain of the inactive inhibitors.Neither MK-912 (3 mg kg−1) nor PMNPQ (0.1 – 1 mg kg−1) altered the duration of anaesthesia induced via a non-alpha2-adrenoceptor pathway (sodium pentobarbitone 50 mg kg−1, i.p.)Central NK1 receptors are involved in PDE4 inhibitor-induced emesis. Consistently, [sar9, Met(O2)11]-substance P (NK1 receptor agonist, 6 μg i.c.v.) reduced the duration of anaesthesia induced by xylazine/ketamine.In summary, this model is functionally coupled to PDE4, specific to alpha2-adrenoceptors and relevant to PDE4 inhibitor-induced emesis. It therefore provides a novel way of evaluating the emetic potential of PDE4 inhibitors in rats. PMID:11786486

  5. Proton Pump Inhibitors and the Prescribing Cascade.

    PubMed

    Rababa, Mohammad; Al-Ghassani, Amal Ali; Kovach, Christine R; Dyer, Elaine M

    2016-04-01

    HOW TO OBTAIN CONTACT HOURS BY READING THIS ARTICLE Instructions 1.3 contact hours will be awarded by Villanova University College of Nursing upon successful completion of this activity. A contact hour is a unit of measurement that denotes 60 minutes of an organized learning activity. This is a learner-based activity. Villanova University College of Nursing does not require submission of your answers to the quiz. A contact hour certificate will be awarded once you register, pay the registration fee, and complete the evaluation form online at http://goo.gl/gMfXaf. To obtain contact hours you must: 1. Read the article, "Proton Pump Inhibitors and the Prescribing Cascade" found on pages 23-31, carefully noting any tables and other illustrative materials that are included to enhance your knowledge and understanding of the content. Be sure to keep track of the amount of time (number of minutes) you spend reading the article and completing the quiz. 2. Read and answer each question on the quiz. After completing all of the questions, compare your answers to those provided within this issue. If you have incorrect answers, return to the article for further study. 3. Go to the Villanova website listed above to register for contact hour credit. You will be asked to provide your name; contact information; and a VISA, MasterCard, or Discover card number for payment of the $20.00 fee. Once you complete the online evaluation, a certificate will be automatically generated. This activity is valid for continuing education credit until March 31, 2019. CONTACT HOURS This activity is co-provided by Villanova University College of Nursing and SLACK Incorporated. Villanova University College of Nursing is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's Commission on Accreditation. ACTIVITY OBJECTIVES 1. Describe the prescribing cascade of proton pump inhibitors (PPI) in nursing home residents. 2. Identify the statistically

  6. Antiplatelet agents and proton pump inhibitors – personalizing treatment

    PubMed Central

    Lin, Eugene; Padmanabhan, Rajiv; Moonis, Majaz

    2010-01-01

    Introduction: Antiplatelet therapy remains one of the cornerstones in the management of non-cardioembolic ischemic stroke. However, a significant percentage of patients have concomitant gastroesophageal reflux or peptic ulcer disease that requires acid-reducing medications, the most powerful and effective being the proton pump inhibitors (PPIs). Antiplatelet efficacy, at least in vivo, and particularly for clopidogrel, has been shown to be reduced with concomitant proton pump inhibitor use. Whether this is clinically relevant is not clear from the limited studies available. Methods: We conducted an extensive review of studies available on Medline related to pharmacodynamic interactions between the antiplatelet medications and proton pump inhibitors as well as clinical studies that addressed this potential interaction. Results: Based on the present pharmacodynamic and clinical studies we did not find a significant interaction that would reduce the efficacy of antiplatelet agents with concomitant user of proton pump inhibitors. Conclusions: Patients on antiplatelet agents after a transient ischemic attack or ischemic stroke can safely use aspirin, and extended release dipyridamole/aspirin with proton pump inhibitors. Patients on clopidogrel may use other acid-reducing drugs besides proton pump inhibitors. In rare cases where proton pump inhibitors and clopidogrel have to be used concurrently, careful close monitoring for recurrent vascular events is required. PMID:23226046

  7. A comparison of four methods for PCR inhibitor removal.

    PubMed

    Hu, Qingqing; Liu, Yuxuan; Yi, Shaohua; Huang, Daixin

    2015-05-01

    Biological samples collected from the crime scenes often contain some compounds that can inhibit the polymerase chain reaction (PCR). The removal of PCR inhibitors from the extracts prior to the PCR amplification is vital for successful forensic DNA typing. This paper aimed to evaluate the ability of four different methods (PowerClean® DNA Clean-Up kit, DNA IQ™ System, Phenol-Chloroform extraction and Chelex®-100 methods) to remove eight commonly encountered PCR inhibitors including: melanin, humic acid, collagen, bile salt, hematin, calcium ions, indigo and urea. Each of these PCR inhibitors was effectively removed by the PowerClean® DNA Clean-Up kit and DNA IQ™ System as demonstrated by generating more complete short tandem repeat (STR) profiles from the cleaned up inhibitor samples than from the raw inhibitor samples. The Phenol-Chloroform extraction and Chelex®-100 methods, however, could only remove some of eight PCR inhibitors. Our results demonstrated that the PowerClean® DNA Clean-Up kit and DNA IQ™ System were very effective for the removal of known PCR inhibitors that are routinely found in DNA extracts from forensic samples. PMID:25553520

  8. Strategies for discovering and derisking covalent, irreversible enzyme inhibitors

    PubMed Central

    Johnson, Douglas S; Weerapana, Eranthie; Cravatt, Benjamin F

    2010-01-01

    This article presents several covalent inhibitors, including examples of successful drugs, as well as highly selective, irreversible inhibitors of emerging therapeutic targets, such as fatty acid amide hydolase. Covalent inhibitors have many desirable features, including increased biochemical efficiency of target disruption, less sensitivity toward pharmacokinetic parameters and increased duration of action that outlasts the pharmacokinetics of the compound. Safety concerns that must be mitigated include lack of specificity and the potential immunogenicity of protein–inhibitor adduct(s). Particular attention will be given to recent technologies, such as activity-based protein profiling, which allow one to define the proteome-wide selectivity patterns for covalent inhibitors in vitro and in vivo. For instance, any covalent inhibitor can, in principle, be modified with a ‘clickable’ tag to generate an activity probe that is almost indistinguishable from the original agent. These probes can be applied to any living system across a broad dose range to fully inventory their on and off targets. The substantial number of drugs on the market today that act by a covalent mechanism belies historical prejudices against the development of irreversibly acting therapeutic small molecules. Emerging proteomic technologies offer a means to systematically discriminate safe (selective) versus deleterious (nonselective) covalent inhibitors and thus should inspire their future design and development. PMID:20640225

  9. Angiotensin-converting enzyme inhibitors in veterinary medicine.

    PubMed

    Lefebvre, H P; Brown, S A; Chetboul, V; King, J N; Pouchelon, J-L; Toutain, P L

    2007-01-01

    Angiotensin-converting enzyme (ACE) inhibitors represent one of the most commonly used categories of drugs in canine and feline medicine. ACE inhibitors currently approved for use in veterinary medicine are benazepril, enalapril, imidapril and ramipril. They are all pro-drugs administered by oral route. A physiologically based model taking into account the saturable binding to ACE has been developed for pharmacokinetic analysis. The bioavailability of the active compounds from their respective pro-drug is low. The active metabolites are eliminated by renal, hepatorenal or biliary excretion, according to the drug. The elimination half-life of the free fraction of the active compounds is very short (ranging from approximately 10 min to 2 h). ACE inhibitors are generally well tolerated. Benazepril, enalapril, imidapril and ramipril are approved for dogs with chronic heart failure (CHF). The efficacy of ACE inhibitors has been convincingly demonstrated in dogs with CHF, especially in those with chronic valvular disease. In such clinical settings, ACE inhibitors improve hemodynamics and clinical signs, and increase survival time. In cats with cardiovascular disease, little information is available except for reports of some benefit in cats with hypertrophic cardiomyopathy in two non-controlled investigations. ACE inhibitors have also a mild to moderate hypotensive effect. There is also evidence to recommend ACE inhibitors in dogs and cats with chronic renal failure (CRF). They decrease the glomerular capillary pressure, have antiproteinuric effects, tend to delay the progression of CRF and to limit the extent of renal lesions. PMID:17506720

  10. Kinases inhibitors in lung cancer: From benchside to bedside.

    PubMed

    Singh, Pankaj Kumar; Singh, Harpreet; Silakari, Om

    2016-08-01

    Lung cancer still remains one of the major causes of cancer related mortality around the globe. Various different molecular targets have been discovered till date for targeting lung cancer. But not every new molecular target has a successfully designed inhibitor; moreover conventional chemotherapeutics have their own limitations such as toxicity and lack of selectivity. Thus, kinases still remain the most effective molecular target in lung cancer therapy. Also, once-shunned kinase inhibitors have recently acquired renewed interest after the development and approval of irreversible kinase inhibitors (such as afatinib) that form covalent bonds with cysteine (or other nucleophilic residues) in the ATP-binding pocket of the kinases. Irreversible kinase inhibitors have a number of potential advantages over conventional reversible kinase inhibitors including prolonged pharmacodynamics, suitability for rational design, high potency etc. This review reveals the current knowledge of all the chemical scaffolds, approved and/or investigational, utilized as inhibitors in lung cancer. It also explains the rationale of designing these along with possible interactions with their targets, biological data and possible problems associated with these inhibitors. PMID:27393082

  11. Covalent EGFR Inhibitors: Binding Mechanisms, Synthetic Approaches, and Clinical Profiles.

    PubMed

    Hossam, Monia; Lasheen, Deena S; Abouzid, Khaled A M

    2016-08-01

    Being overexpressed in several types of cancer, the epidermal growth factor receptor (EGFR) is considered one of the key therapeutic targets in oncology. Although many first-generation EGFR inhibitors had been FDA approved for the treatment of certain types of cancer, patients soon developed resistance to these reversible ATP competitive inhibitors via mutations in the kinase domain of EGFR. A new trend was adopted to design covalent irreversible inhibitors, that is, second- and third-generation inhibitors. Second-generation inhibitors can inhibit the mutant forms but, unfortunately, they had dose limiting side effects due to wild-type EGFR inhibition. Third-generation inhibitors emerged shortly, which were capable of inhibiting the mutant forms exclusively while sparing the wild type. Many other strategies have also been developed to reduce the risk of covalent interactions with off-targets, thus improving the pharmacokinetic and/or pharmacodynamic profile of the antiproliferative agents. In this review, we focused mainly on second- and third-generation EGFR inhibitors, their binding mechanisms (either docking studies or co-crystallized structures), their synthetic approaches, clinical profiles, and limitations. PMID:27258393

  12. RAF inhibitors that evade paradoxical MAPK pathway activation.

    PubMed

    Zhang, Chao; Spevak, Wayne; Zhang, Ying; Burton, Elizabeth A; Ma, Yan; Habets, Gaston; Zhang, Jiazhong; Lin, Jack; Ewing, Todd; Matusow, Bernice; Tsang, Garson; Marimuthu, Adhirai; Cho, Hanna; Wu, Guoxian; Wang, Weiru; Fong, Daniel; Nguyen, Hoa; Shi, Songyuan; Womack, Patrick; Nespi, Marika; Shellooe, Rafe; Carias, Heidi; Powell, Ben; Light, Emily; Sanftner, Laura; Walters, Jason; Tsai, James; West, Brian L; Visor, Gary; Rezaei, Hamid; Lin, Paul S; Nolop, Keith; Ibrahim, Prabha N; Hirth, Peter; Bollag, Gideon

    2015-10-22

    Oncogenic activation of BRAF fuels cancer growth by constitutively promoting RAS-independent mitogen-activated protein kinase (MAPK) pathway signalling. Accordingly, RAF inhibitors have brought substantially improved personalized treatment of metastatic melanoma. However, these targeted agents have also revealed an unexpected consequence: stimulated growth of certain cancers. Structurally diverse ATP-competitive RAF inhibitors can either inhibit or paradoxically activate the MAPK pathway, depending whether activation is by BRAF mutation or by an upstream event, such as RAS mutation or receptor tyrosine kinase activation. Here we have identified next-generation RAF inhibitors (dubbed 'paradox breakers') that suppress mutant BRAF cells without activating the MAPK pathway in cells bearing upstream activation. In cells that express the same HRAS mutation prevalent in squamous tumours from patients treated with RAF inhibitors, the first-generation RAF inhibitor vemurafenib stimulated in vitro and in vivo growth and induced expression of MAPK pathway response genes; by contrast the paradox breakers PLX7904 and PLX8394 had no effect. Paradox breakers also overcame several known mechanisms of resistance to first-generation RAF inhibitors. Dissociating MAPK pathway inhibition from paradoxical activation might yield both improved safety and more durable efficacy than first-generation RAF inhibitors, a concept currently undergoing human clinical evaluation with PLX8394. PMID:26466569

  13. CaMKII inhibitors: from research tools to therapeutic agents

    PubMed Central

    Pellicena, Patricia; Schulman, Howard

    2014-01-01

    The cardiac field has benefited from the availability of several CaMKII inhibitors serving as research tools to test putative CaMKII pathways associated with cardiovascular physiology and pathophysiology. Successful demonstrations of its critical pathophysiological roles have elevated CaMKII as a key target in heart failure, arrhythmia, and other forms of heart disease. This has caught the attention of the pharmaceutical industry, which is now racing to develop CaMKII inhibitors as safe and effective therapeutic agents. While the first generation of CaMKII inhibitor development is focused on blocking its activity based on ATP binding to its catalytic site, future inhibitors can also target sites affecting its regulation by Ca2+/CaM or translocation to some of its protein substrates. The recent availability of crystal structures of the kinase in the autoinhibited and activated state, and of the dodecameric holoenzyme, provides insights into the mechanism of action of existing inhibitors. It is also accelerating the design and development of better pharmacological inhibitors. This review examines the structure of the kinase and suggests possible sites for its inhibition. It also analyzes the uses and limitations of current research tools. Development of new inhibitors will enable preclinical proof of concept tests and clinical development of successful lead compounds, as well as improved research tools to more accurately examine and extend knowledge of the role of CaMKII in cardiac health and disease. PMID:24600394

  14. Diabetes therapies in hemodialysis patients: Dipeptidase-4 inhibitors.

    PubMed

    Nakamura, Yuya; Hasegawa, Hitomi; Tsuji, Mayumi; Udaka, Yuko; Mihara, Masatomo; Shimizu, Tatsuo; Inoue, Michiyasu; Goto, Yoshikazu; Gotoh, Hiromichi; Inagaki, Masahiro; Oguchi, Katsuji

    2015-06-25

    Although several previous studies have been published on the effects of dipeptidase-4 (DPP-4) inhibitors in diabetic hemodialysis (HD) patients, the findings have yet to be reviewed comprehensively. Eyesight failure caused by diabetic retinopathy and aging-related dementia make multiple daily insulin injections difficult for HD patients. Therefore, we reviewed the effects of DPP-4 inhibitors with a focus on oral antidiabetic drugs as a new treatment strategy in HD patients with diabetes. The following 7 DPP-4 inhibitors are available worldwide: sitagliptin, vildagliptin, alogliptin, linagliptin, teneligliptin, anagliptin, and saxagliptin. All of these are administered once daily with dose adjustments in HD patients. Four types of oral antidiabetic drugs can be administered for combination oral therapy with DPP-4 inhibitors, including sulfonylureas, meglitinide, thiazolidinediones, and alpha-glucosidase inhibitor. Nine studies examined the antidiabetic effects in HD patients. Treatments decreased hemoglobin A1c and glycated albumin levels by 0.3% to 1.3% and 1.7% to 4.9%, respectively. The efficacy of DPP-4 inhibitor treatment is high among HD patients, and no patients exhibited significant severe adverse effects such as hypoglycemia and liver dysfunction. DPP-4 inhibitors are key drugs in new treatment strategies for HD patients with diabetes and with limited choices for diabetes treatment. PMID:26131325

  15. Antitumoral activity of allosteric inhibitors of protein kinase CK2

    PubMed Central

    Sautel, Céline F.; Teillet, Florence; Barette, Caroline; Lafanechere, Laurence; Receveur-Brechot, Veronique; Cochet, Claude

    2011-01-01

    Introduction Due to its physiological role into promoting cell survival and its dysregulation in most cancer cells, protein kinase CK2 is a relevant physiopathological target for development of chemical inhibitors. We report the discovery of azonaphthalene derivatives, as a new family of highly specific CK2 inhibitors. First, we demonstrated that CK2 inhibition (IC50= 0.4 μM) was highly specific, reversible and non ATP-competitive. Small Angle X-ray Scattering experiments showed that this inhibition was due to large conformational change of CK2α upon binding of these inhibitors. We showed that several compounds of the family were cell-potent CK2 inhibitors promoting cell cycle arrest of human glioblastoma U373 cells. Finally, in vitro and in vivo assays showed that these compounds could decrease U373 cell tumor mass by 83% emphasizing their efficacy against these apoptosis-resistant tumors. In contrast, Azonaphthalene derivatives inactive on CK2 activity showed no effect in colony formation and tumor regression assays. These findings illustrate the emergence of nonclassical CK2 inhibitors and provide exciting opportunities for the development of novel allosteric CK2 inhibitors. Background CK2 is an emerging therapeutic target and ATP-competitive inhibitors have been identified. CK2 is endowed with specific structural features providing alternative strategies for inhibition. Results Azonaphthalene compounds are allosteric CK2 inhibitors showing antitumor activity. Conclusion CK2 may be targeted allosterically. Significance These inhibitors provide a foundation for a new paradigm for specific CK2 inhibition. PMID:22184283

  16. Antimalarial Activity of the Anticancer Histone Deacetylase Inhibitor SB939

    PubMed Central

    Sumanadasa, Subathdrage D. M.; Goodman, Christopher D.; Lucke, Andrew J.; Skinner-Adams, Tina; Sahama, Ishani; Haque, Ashraful; Do, Tram Anh; McFadden, Geoffrey I.; Fairlie, David P.

    2012-01-01

    Histone deacetylase (HDAC) enzymes posttranslationally modify lysines on histone and nonhistone proteins and play crucial roles in epigenetic regulation and other important cellular processes. HDAC inhibitors (e.g., suberoylanilide hydroxamic acid [SAHA; also known as vorinostat]) are used clinically to treat some cancers and are under investigation for use against many other diseases. Development of new HDAC inhibitors for noncancer indications has the potential to be accelerated by piggybacking onto cancer studies, as several HDAC inhibitors have undergone or are undergoing clinical trials. One such compound, SB939, is a new orally active hydroxamate-based HDAC inhibitor with an improved pharmacokinetic profile compared to that of SAHA. In this study, the in vitro and in vivo antiplasmodial activities of SB939 were investigated. SB939 was found to be a potent inhibitor of the growth of Plasmodium falciparum asexual-stage parasites in vitro (50% inhibitory concentration [IC50], 100 to 200 nM), causing hyperacetylation of parasite histone and nonhistone proteins. In combination with the aspartic protease inhibitor lopinavir, SB939 displayed additive activity. SB939 also potently inhibited the in vitro growth of exoerythrocytic-stage Plasmodium parasites in liver cells (IC50, ∼150 nM), suggesting that inhibitor targeting to multiple malaria parasite life cycle stages may be possible. In an experimental in vivo murine model of cerebral malaria, orally administered SB939 significantly inhibited P. berghei ANKA parasite growth, preventing development of cerebral malaria-like symptoms. These results identify SB939 as a potent new antimalarial HDAC inhibitor and underscore the potential of investigating next-generation anticancer HDAC inhibitors as prospective new drug leads for treatment of malaria. PMID:22508312

  17. mTOR Inhibitors Alone and in Combination with JAK2 Inhibitors Effectively Inhibit Cells of Myeloproliferative Neoplasms

    PubMed Central

    Martinelli, Serena; Tozzi, Lorenzo; Guglielmelli, Paola; Bosi, Alberto; Vannucchi, Alessandro M.

    2013-01-01

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

  18. The dawn of hedgehog inhibitors: Vismodegib.

    PubMed

    Sandhiya, Selvarajan; Melvin, George; Kumar, Srinivasamurthy Suresh; Dkhar, Steven Aibor

    2013-01-01

    Cancer, one of the leading causes of death worldwide is estimated to increase to approximately 13.1 million by 2030. This has amplified the research in oncology towards the exploration of novel targets. Recently there has been lots of interest regarding the hedgehog (Hh) pathway, which plays a significant role in the development of organs and tissues during embryonic and postnatal periods. In a normal person, the Hh signaling pathway is under inhibition and gets activated upon the binding of Hh ligand to a transmembrane receptor called Patched (PTCH1) thus allowing the transmembrane protein, smoothened (SMO) to transfer signals through various proteins. One of the newer drugs namely vismodegib involves the inhibition of Hh pathway and has shown promising results in the treatment of advanced basal-cell carcinoma as well as medulloblastoma. It has been granted approval by US Food and Drug Administration's (US FDA) priority review program on January 30, 2012 for the treatment of advanced basal-cell carcinoma. The drug is also being evaluated in malignancies like medulloblastoma, pancreatic cancer, multiple myeloma, chondrosarcoma and prostate cancer. Moreover various Hh inhibitors namely LDE 225, saridegib, BMS 833923, LEQ 506, PF- 04449913 and TAK-441 are also undergoing phase I and II trials for different neoplasms. Hence this review will describe briefly the Hh pathway and the novel drug vismodegib. PMID:23662017

  19. γ-Secretase inhibitors and modulators.

    PubMed

    Golde, Todd E; Koo, Edward H; Felsenstein, Kevin M; Osborne, Barbara A; Miele, Lucio

    2013-12-01

    γ-Secretase is a fascinating, multi-subunit, intramembrane cleaving protease that is now being considered as a therapeutic target for a number of diseases. Potent, orally bioavailable γ-secretase inhibitors (GSIs) have been developed and tested in humans with Alzheimer's disease (AD) and cancer. Preclinical studies also suggest the therapeutic potential for GSIs in other disease conditions. However, due to inherent mechanism based-toxicity of non-selective inhibition of γ-secretase, clinical development of GSIs will require empirical testing with careful evaluation of benefit versus risk. In addition to GSIs, compounds referred to as γ-secretase modulators (GSMs) remain in development as AD therapeutics. GSMs do not inhibit γ-secretase, but modulate γ-secretase processivity and thereby shift the profile of the secreted amyloid β peptides (Aβ) peptides produced. Although GSMs are thought to have an inherently safe mechanism of action, their effects on substrates other than the amyloid β protein precursor (APP) have not been extensively investigated. Herein, we will review the current state of development of GSIs and GSMs and explore pertinent biological and pharmacological questions pertaining to the use of these agents for select indications. This article is part of a Special Issue entitled: Intramembrane Proteases. PMID:23791707

  20. Suppression of Coronavirus Replication by Cyclophilin Inhibitors

    PubMed Central

    Tanaka, Yoshikazu; Sato, Yuka; Sasaki, Takashi

    2013-01-01

    Coronaviruses infect a variety of mammalian and avian species and cause serious diseases in humans, cats, mice, and birds in the form of severe acute respiratory syndrome (SARS), feline infectious peritonitis (FIP), mouse hepatitis, and avian infectious bronchitis, respectively. No effective vaccine or treatment has been developed for SARS-coronavirus or FIP virus, both of which cause lethal diseases. It has been reported that a cyclophilin inhibitor, cyclosporin A (CsA), could inhibit the replication of coronaviruses. CsA is a well-known immunosuppressive drug that binds to cellular cyclophilins to inhibit calcineurin, a calcium-calmodulin-activated serine/threonine-specific phosphatase. The inhibition of calcineurin blocks the translocation of nuclear factor of activated T cells from the cytosol into the nucleus, thus preventing the transcription of genes encoding cytokines such as interleukin-2. Cyclophilins are peptidyl-prolyl isomerases with physiological functions that have been described for many years to include chaperone and foldase activities. Also, many viruses require cyclophilins for replication; these include human immunodeficiency virus, vesicular stomatitis virus, and hepatitis C virus. However, the molecular mechanisms leading to the suppression of viral replication differ for different viruses. This review describes the suppressive effects of CsA on coronavirus replication. PMID:23698397

  1. Trial watch: IDO inhibitors in cancer therapy

    PubMed Central

    Vacchelli, Erika; Aranda, Fernando; Eggermont, Alexander; Sautès-Fridman, Catherine; Tartour, Eric; Kennedy, Eugene P; Platten, Michael; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    Indoleamine 2,3-dioxigenase 1 (IDO1) is the main enzyme that catalyzes the first, rate-limiting step of the so-called “kynurenine pathway”, i.e., the metabolic cascade that converts the essential amino acid L-tryptophan (Trp) into L-kynurenine (Kyn). IDO1, which is expressed constitutively by some tissues and in an inducible manner by specific subsets of antigen-presenting cells, has been shown to play a role in the establishment and maintenance of peripheral tolerance. At least in part, this reflects the capacity of IDO1 to restrict the microenvironmental availability of Trp and to favor the accumulation of Kyn and some of its derivatives. Also, several neoplastic lesions express IDO1, providing them with a means to evade anticancer immunosurveillance. This consideration has driven the development of several IDO1 inhibitors, some of which (including 1-methyltryptophan) have nowadays entered clinical evaluation. In animal tumor models, the inhibition of IDO1 by chemical or genetic interventions is indeed associated with the (re)activation of therapeutically relevant anticancer immune responses. This said, several immunotherapeutic regimens exert robust clinical activity in spite of their ability to promote the expression of IDO1. Moreover, 1-methyltryptophan has recently been shown to exert IDO1-independent immunostimulatory effects. Here, we summarize the preclinical and clinical studies testing the antineoplastic activity of IDO1-targeting interventions. PMID:25941578

  2. Suppression of coronavirus replication by cyclophilin inhibitors.

    PubMed

    Tanaka, Yoshikazu; Sato, Yuka; Sasaki, Takashi

    2013-05-01

    Coronaviruses infect a variety of mammalian and avian species and cause serious diseases in humans, cats, mice, and birds in the form of severe acute respiratory syndrome (SARS), feline infectious peritonitis (FIP), mouse hepatitis, and avian infectious bronchitis, respectively. No effective vaccine or treatment has been developed for SARS-coronavirus or FIP virus, both of which cause lethal diseases. It has been reported that a cyclophilin inhibitor, cyclosporin A (CsA), could inhibit the replication of coronaviruses. CsA is a well-known immunosuppressive drug that binds to cellular cyclophilins to inhibit calcineurin, a calcium-calmodulin-activated serine/threonine-specific phosphatase. The inhibition of calcineurin blocks the translocation of nuclear factor of activated T cells from the cytosol into the nucleus, thus preventing the transcription of genes encoding cytokines such as interleukin-2. Cyclophilins are peptidyl-prolyl isomerases with physiological functions that have been described for many years to include chaperone and foldase activities. Also, many viruses require cyclophilins for replication; these include human immunodeficiency virus, vesicular stomatitis virus, and hepatitis C virus. However, the molecular mechanisms leading to the suppression of viral replication differ for different viruses. This review describes the suppressive effects of CsA on coronavirus replication. PMID:23698397

  3. Screening approaches to generating STAT inhibitors

    PubMed Central

    Walker, Sarah R.; Frank, David A.

    2012-01-01

    STAT transcription factors are regulators of critical cellular processes such as proliferation, survival, and self-renewal. While the activity of these proteins is tightly regulated under physiological conditions, they can become constitutively activated in a broad range of human cancers. This inappropriate STAT activation leads to enhanced transcription of genes that can directly lead to the malignant phenotype. Since STATs are largely dispensable for normal cell function, this has raised the possibility that STATs might be key targets for cancer therapy. Although a number of structure-based strategies have been used to develop STAT inhibitors, an alternate approach is to use cell-based assays that make use of the transcriptional function of STATs. Employing these systems, one can screen large chemical libraries to identify compounds that specifically block the function of a given STAT. This approach can lead to the identification of compounds that inhibit STATs by a variety of mechanisms, and can suggest novel targets for therapy. This type of functional screening strategy has already identified a drug that potently inhibits STAT3, and which is now being evaluated in a clinical trial for patients with chronic lymphocytic leukemia. PMID:24058786

  4. Antiplatelet drug interactions with proton pump inhibitors

    PubMed Central

    Scott, Stuart A; Obeng, Aniwaa Owusu; Hulot, Jean-Sébastien

    2014-01-01

    Introduction Non-aspirin antiplatelet agents (e.g., clopidogrel, prasugrel, ticagrelor) are commonly prescribed for the prevention of recurrent cardiovascular events among patients with acute coronary syndromes (ACS) and/or those undergoing percutaneous coronary intervention (PCI). In addition, combination therapy with proton pump inhibitors (PPIs) is often recommended to attenuate gastrointestinal bleeding risk, particularly during dual antiplatelet therapy (DAPT) with clopidogrel and aspirin. Importantly, a pharmacological interaction between clopidogrel and some PPIs has been proposed based on mutual CYP450-dependent metabolism, but available evidence is inconsistent. Areas covered This article provides an overview of the currently approved antiplatelet agents and PPIs, including their metabolic pathways. Additionally, the CYP450 isoenzyme at the center of the drug interaction, CYP2C19, is described in detail, and the available evidence on both the potential pharmacological interaction and influence on clinical outcomes are summarized and evaluated. Expert opinion Although concomitant DAPT and PPI use reduces clopidogrel active metabolite levels and ex vivo-measured platelet inhibition, the influence of the drug interaction on clinical outcomes has been conflicting and largely reported from non-randomized observational studies. Despite this inconsistency, a clinically important interaction cannot be definitively excluded, particularly among patient subgroups with higher overall cardiovascular risk and potentially among CYP2C19 loss-of-function allele carriers. PMID:24205916

  5. Synthesis of new sulfonamides as lipoxygenase inhibitors.

    PubMed

    Mustafa, Ghulam; Khan, Islam Ullah; Ashraf, Muhammad; Afzal, Iftikhar; Shahzad, Sohail Anjum; Shafiq, Muhammad

    2012-04-15

    The present study describes a convenient method for the synthesis of new lipoxygenase inhibitors, 4-(toluene-4-sulfonylamino)-benzoic acids from p-amino benzoic acid. Reaction of p-amino benzoic acid with p-toluenesulfonyl chloride provided thirteen N- and O-alkylation products 4a-4m in moderate to good yields. Lipoxygenase inhibition of newly formed sulfonamide derivatives was investigated and some of these compounds 4m, 4g, 4e, 4f and 4j showed good lipoxygenase inhibitory activities with IC(50) values ranged between 15.8 ± 0.57 and 91.7 ± 0.61 μmol whilst all other compounds exhibited mild anti-lipoxygenase activities with IC(50) values ranged between 139.2 ± 0.75 and 232.1 ± 0.78 μmol. N-alkylated products were more active against the enzyme than O-alkylated or both N- and O-alkylated ones. All synthesized sulfonamides were recrystallized in chloroform to give these title compounds which were characterized using FTIR, (1)H NMR, (13)C NMR, elemental analysis and single crystal X-ray diffraction techniques. PMID:22436389

  6. Virtual Target Screening: Validation Using Kinase Inhibitors

    PubMed Central

    Santiago, Daniel N.; Pevzner, Yuri; Durand, Ashley A.; Tran, MinhPhuong; Scheerer, Rachel R.; Daniel, Kenyon; Sung, Shen-Shu; Woodcock, H. Lee; Guida, Wayne C.; Brooks, Wesley H.

    2012-01-01

    Computational methods involving virtual screening could potentially be employed to discover new biomolecular targets for an individual molecule of interest (MOI). However, existing scoring functions may not accurately differentiate proteins to which the MOI binds from a larger set of macromolecules in a protein structural database. An MOI will most likely have varying degrees of predicted binding affinities to many protein targets. However, correctly interpreting a docking score as a hit for the MOI docked to any individual protein can be problematic. In our method, which we term “Virtual Target Screening (VTS)”, a set of small drug-like molecules are docked against each structure in the protein library to produce benchmark statistics. This calibration provides a reference for each protein so that hits can be identified for an MOI. VTS can then be used as tool for: drug repositioning (repurposing), specificity and toxicity testing, identifying potential metabolites, probing protein structures for allosteric sites, and testing focused libraries (collection of MOIs with similar chemotypes) for selectivity. To validate our VTS method, twenty kinase inhibitors were docked to a collection of calibrated protein structures. Here we report our results where VTS predicted protein kinases as hits in preference to other proteins in our database. Concurrently, a graphical interface for VTS was developed. PMID:22747098

  7. Therapeutic drug monitoring and tyrosine kinase inhibitors

    PubMed Central

    Herviou, Pauline; Thivat, Emilie; Richard, Damien; Roche, Lucie; Dohou, Joyce; Pouget, Mélanie; Eschalier, Alain; Durando, Xavier; Authier, Nicolas

    2016-01-01

    The therapeutic activity of drugs can be optimized by establishing an individualized dosage, based on the measurement of the drug concentration in the serum, particularly if the drugs are characterized by an inter-individual variation in pharmacokinetics that results in an under- or overexposure to treatment. In recent years, several tyrosine kinase inhibitors (TKIs) have been developed to block intracellular signaling pathways in tumor cells. These oral drugs are candidates for therapeutic drug monitoring (TDM) due to their high inter-individual variability for therapeutic and toxic effects. Following a literature search on PubMed, studies on TKIs and their pharmacokinetic characteristics, plasma quantification and inter-individual variability was studied. TDM is commonly used in various medical fields, including cardiology and psychiatry, but is not often applied in oncology. Plasma concentration monitoring has been thoroughly studied for imatinib, in order to evaluate the usefulness of TDM. The measurement of plasma concentration can be performed by various analytical techniques, with liquid chromatography-mass spectrometry being the reference method. This method is currently used to monitor the efficacy and tolerability of imatinib treatments. Although TDM is already being used for imatinib, additional studies are required in order to improve this practice with the inclusion of other TKIs. PMID:27446421

  8. Are proton pump inhibitors really so dangerous?

    PubMed

    Savarino, Vincenzo; Dulbecco, Pietro; Savarino, Edoardo

    2016-08-01

    For decades, millions of patients with acid-related disorders have had their acid inhibited effectively and safely first with H2-receptor antagonists (H2RAs) and then with proton pump inhibitors (PPI). As with any pharmacological agent, PPIs have been reported to be associated with some adverse events, but several recent large-scale observational studies have evidenced new and serious abnormalities generally linked to their chronic use. However, these studies have often important limitations for their frequent retrospective design and other methodological drawbacks, such as selection biases of the analyzed populations and the presence of various confounding factors. Overall, although the conclusions of these pharmacovigilant investigations must be taken into account and can generate important hypotheses for future research, they do not have to create panic among patients and alarmism among physicians. On considering the weakness of these studies, we suggest physicians should not refrain from continuing to use PPIs, if these drugs are given for medical indications clearly established in the literature and, more importantly, they should not be induced to shift to H2RAs, a class of antisecretory agents that are much less effective than PPIs. A return to the past is potentially dangerous for the patients, taking into account the well-known success of PPIs in the wide spectrum of all acid-related conditions. PMID:27321544

  9. Xanthine oxidase inhibitors from Garcinia esculenta twigs.

    PubMed

    Zhu, Lun-Lun; Fu, Wen-Wei; Watanabe, Shimpei; Shao, Yi-Nuo; Tan, Hong-Sheng; Zhang, Hong; Tan, Chang-Heng; Xiu, Yan-Feng; Norimoto, Hisayoshi; Xu, Hong-Xi

    2014-12-01

    The EtOAc-soluble portion of the 80 % (v/v) EtOH extract from the twigs of Garcinia esculenta exhibited strong xanthine oxidase inhibition in vitro. Bioassay-guided purification led to the isolation of 1,3,6,7-tetrahydroxyxanthone (3) and griffipavixanthone (8) as the main xanthine oxidase inhibitors, along with six additional compounds (1, 2, 4-7), including two new compounds (1 and 2). This enzyme inhibition was dose dependent with an IC50 value of approximately 1.2 µM for 3 and 6.3 µM for 8. The inhibitory activity of 3 was stronger than the control allopurinol (IC50 value: 5.3 µM). To our knowledge, compound 8 is the first bixanthone that demonstrated potent XO inhibitory activity in vitro. The structures of the new compounds were established by spectroscopic analysis, and the optical properties and absolute stereochemistry of racemic (±) esculentin A (2) were further determined by the calculation of the DP4 probability and analysis of its MTPA ester derivatives. PMID:25340468

  10. Protein kinase inhibitors against malignant lymphoma

    PubMed Central

    D’Cruz, Osmond J; Uckun, Fatih M

    2013-01-01

    Introduction Tyrosine kinases (TKs) are intimately involved in multiple signal transduction pathways regulating survival, activation, proliferation and differentiation of lymphoid cells. Deregulation or overexpression of specific oncogenic TKs is implicated in maintaining the malignant phenotype in B-lineage lymphoid malignancies. Several novel targeted TK inhibitors (TKIs) have recently emerged as active in the treatment of relapsed or refractory B-cell lymphomas that inhibit critical signaling pathways, promote apoptotic mechanisms or modulate the tumor microenvironment. Areas covered In this review, the authors summarize the clinical outcomes of newer TKIs in various B-cell lymphomas from published and ongoing clinical studies and abstracts from major cancer and hematology conferences. Expert opinion Multiple clinical trials have demonstrated that robust antitumor activity can be obtained with TKIs directed toward specific oncogenic TKs that are genetically deregulated in various subtypes of B-cell lymphomas. Clinical success of targeting TKIs is dependent upon on identifying reliable molecular and clinical markers associated with select cohorts of patients. Further understanding of the signaling pathways should stimulate the identification of novel molecular targets and expand the development of new therapeutic options and individualized therapies. PMID:23496343

  11. Inhibitors of Ras-SOS Interactions.

    PubMed

    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. PMID:26630662

  12. Probing translation using small molecule inhibitors

    PubMed Central

    Blanchard, Scott C.; Cooperman, Barry S.; Wilson, Daniel N.

    2010-01-01

    Summary The translational apparatus of the bacterial cell remains one of the principal targets of antibiotics for the clinical treatment of infection worldwide. Since the introduction of specific translation inhibitors into clinical practise in the late 1940’s, intense efforts have been made to understand their precise mechanisms of action. Such research has often revealed significant and sometimes unexpected insights into many fundamental aspects of the translation mechanism. Central to progress in this area, high-resolution crystal structures of the bacterial ribosome identifying the sites of antibiotic binding are now available, which, together with recent developments in single-molecule and fast-kinetic approaches, provide an integrated view of the dynamic translation process. Assays employing these approaches and focusing on specific steps of the overall translation process are amenable for drug-screening. Such assays, coupled with structural studies, have the potential not only to accelerate the discovery of novel and effective antimicrobial agents, but also to refine our understanding of the translation mechanism, since antibiotics often stabilize specific functional states of the ribosome and allow distinct translation steps to be dissected in molecular detail. PMID:20609413

  13. Evolutionary origin of inhibitor cystine knot peptides.

    PubMed

    Zhu, Shunyi; Darbon, Herve; Dyason, Karin; Verdonck, Fons; Tytgat, Jan

    2003-09-01

    The inhibitor cystine knot (ICK) fold is an evolutionarily conserved structural motif shared by a large group of polypeptides with diverse sequences and bioactivities. Although found in different phyla (animal, plant, and fungus), ICK peptides appear to be most prominent in venoms of cone snail and spider. Recently, two scorpion toxins activating a calcium release channel have been found to adopt an ICK fold. We have isolated and identified both cDNA and genomic clones for this family of ICK peptides from the scorpion Opistophthalmus carinatus. The gene characterized by three well-delineated exons respectively coding for three structural and functional domains in the toxin precursors illustrates the correlation between exon and module as suggested by the "exon theory of genes." Based on the analysis of precursor organization and gene structure combined with the 3-D fold and functional data, our results highlight a common evolutionary origin for ICK peptides from animals. In contrast, ICK peptides from plant and fungus might be independently evolved from another ancestor. PMID:12958203

  14. A novel coagulation inhibitor from Schistosoma japonicum.

    PubMed

    Ranasinghe, Shiwanthi L; Fischer, Katja; Gobert, Geoffrey N; McManus, Donald P

    2015-12-01

    Little is known about the molecular mechanisms whereby the human blood fluke Schistosoma japonicum is able to survive in the host venous blood system. Protease inhibitors are likely released by the parasite enabling it to avoid attack by host proteolytic enzymes and coagulation factors. Interrogation of the S. japonicum genomic sequence identified a gene, SjKI-1, homologous to that encoding a single domain Kunitz protein (Sjp_0020270) which we expressed in recombinant form in Escherichia coli and purified. SjKI-1 is highly transcribed in adult worms and eggs but its expression was very low in cercariae and schistosomula. In situ immunolocalization with anti-SjKI-1 rabbit antibodies showed the protein was present in eggs trapped in the infected mouse intestinal wall. In functional assays, SjKI-1 inhibited trypsin in the picomolar range and chymotrypsin, neutrophil elastase, FXa and plasma kallikrein in the nanomolar range. Furthermore, SjKI-1, at a concentration of 7·5 µ m, prolonged 2-fold activated partial thromboplastin time of human blood coagulation. We also demonstrate that SjKI-1 has the ability to bind Ca(++). We present, therefore, characterization of the first Kunitz protein from S. japonicum which we show has an anti-coagulant properties. In addition, its inhibition of neutrophil elastase indicates SjKI-1 have an anti-inflammatory role. Having anti-thrombotic properties, SjKI-1 may point the way towards novel treatment for hemostatic disorders. PMID:26463744

  15. Proton pump inhibitors and risk of dementia

    PubMed Central

    Thongprayoon, Charat; Panjawatanan, Panadeekarn; Ungprasert, Patompong

    2016-01-01

    Background Proton pump inhibitors (PPIs) are one of the most commonly prescribed medications. Recent studies have raised a concern over increased risk of dementia among PPIs users but the results of those studies were inconsistent. We conducted this systematic review and meta-analysis to summarize all available data. Methods A literature search was performed in MEDLINE and EMBASE database from inception to April 2016. Observational studies that reported risk of dementia among PPIs users compared with non-users were included. Point estimates were extracted from individual studies and pooled risk ratios (RR) with 95% confidence intervals (CI) were calculated using a random-effect, generic inverse variance method. Results Four studies were included in the analysis. Pooled RR of dementia among PPIs users compared with non-users was 1.08 (95% CI, 0.82–1.43). Sensitivity analysis including only cohort studies demonstrated a higher risk with pooled RR of 1.44 (95% CI, 1.36–1.52). Conclusions Our study demonstrated an increased risk of dementia among PPIs users. Whether this association is causal requires further investigations. PMID:27429966

  16. Small molecule phagocytosis inhibitors for immune cytopenias.

    PubMed

    Neschadim, Anton; Kotra, Lakshmi P; Branch, Donald R

    2016-08-01

    Immune cytopenias are conditions characterized by low blood cell counts, such as platelets in immune thrombocytopenia (ITP) and red blood cells in autoimmune hemolytic anemia (AIHA). Chronic ITP affects approximately 4 in 100,000 adults annually while AIHA is much less common. Extravascular phagocytosis and massive destruction of autoantibody-opsonized blood cells by macrophages in the spleen and liver are the hallmark of these conditions. Current treatment modalities for ITP and AIHA include the first-line use of corticosteroids; whereas, IVIg shows efficacy in ITP but not AIHA. One main mechanism of action by which IVIg treatment leads to the reduction in platelet destruction rates in ITP is thought to involve Fcγ receptor (FcγR) blockade, ultimately leading to the inhibition of extravascular platelet phagocytosis. IVIg, which is manufactured from the human plasma of thousands of donors, is a limited resource, and alternative treatments, particularly those based on bioavailable small molecules, are needed. In this review, we overview the pathophysiology of ITP, the role of Fcγ receptors, and the mechanisms of action of IVIg in treating ITP, and outline the efforts and progress towards developing novel, first-in-class inhibitors of phagocytosis as synthetic, small molecule substitutes for IVIg in ITP and other conditions where the pathobiology of the disease involves phagocytosis. PMID:27296447

  17. Interpreting clinical assays for histone deacetylase inhibitors

    PubMed Central

    Martinet, Nadine; Bertrand, Philippe

    2011-01-01

    As opposed to genetics, dealing with gene expressions by direct DNA sequence modifications, the term epigenetics applies to all the external influences that target the chromatin structure of cells with impact on gene expression unrelated to the sequence coding of DNA itself. In normal cells, epigenetics modulates gene expression through all development steps. When “imprinted” early by the environment, epigenetic changes influence the organism at an early stage and can be transmitted to the progeny. Together with DNA sequence alterations, DNA aberrant cytosine methylation and microRNA deregulation, epigenetic modifications participate in the malignant transformation of cells. Their reversible nature has led to the emergence of the promising field of epigenetic therapy. The efforts made to inhibit in particular the epigenetic enzyme family called histone deacetylases (HDACs) are described. HDAC inhibitors (HDACi) have been proposed as a viable clinical therapeutic approach for the treatment of leukemia and solid tumors, but also to a lesser degree for noncancerous diseases. Three epigenetic drugs are already arriving at the patient’s bedside, and more than 100 clinical assays for HDACi are registered on the National Cancer Institute website. They explore the eventual additive benefits of combined therapies. In the context of the pleiotropic effects of HDAC isoforms, more specific HDACi and more informative screening tests are being developed for the benefit of the patients. PMID:21625397

  18. Cholinesterase inhibitors: cardioprotection in Alzheimer's disease.

    PubMed

    Monacelli, Fiammetta; Rosa, Gianmarco

    2014-01-01

    Alzheimer's disease is a life shortening disease, and the lack of disease modifying therapy implies a huge impact on life expectancy as well as an outgrowing financial and socioeconomic burden. Cholinesterase inhibitors (ChEIs) represent the first line symptomatic therapy, whose benefit to harm ratio is still a matter of debate. Acetylcholinesterase enzyme is a core interest for pharmacological and toxicological research to unmask the fine balance between therapeutic drug efficacy, tolerability, safety, and detrimental effects up to adverse drug reaction. So far, a body of evidence advocated that an increased vagal tone was associated to an increased risk of gastrointestinal and cardiac side effects (negative chronotropic, arrhytmogenic, hypotensive effects), able to hamper ChEIs effects on cognition, reducing administration feasibility and compliance, especially in older and comorbid patients. Conversely, a growing body of evidence is indicating a protective role of ChEIs on overall cardiovascular mortality in patients with dementia, through a series of in vitro and in vivo investigations. The present review is aimed to report the up to date literature in the controversial field of ChEIs and cardioprotection in dementia, offering a state of the art, which may constitute the conceptual framework to be enlarged in order to build higher evidence. Chronic vagal nerve stimulation acted upon by donepezil might improve long term survival through pharmacological properties apart from cholinesterase inhibition, able to offer cardioprotection, abating the overall cardiovascular risk, and, thus profiling a new line of therapeutic intervention for ChEI drug class. PMID:25024324

  19. Pharmacotherapies for Alzheimer's disease: beyond cholinesterase inhibitors.

    PubMed

    Tayeb, Haythum O; Yang, Hyun Duk; Price, Bruce H; Tarazi, Frank I

    2012-04-01

    Alzheimer's disease (AD) is the most common cause of memory impairment and dementia in the elderly. AD is pathologically characterized by extracellular deposits of beta-amyloid (Aβ) peptide, neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau, neuronal loss, and neurotransmitter dysfunction. Clinically, AD is characterized by progressive cognitive decline that usually starts with memory impairment and progresses to cause a more generalized cognitive dysfunction, behavioral dysregulation, and neuropsychiatric symptoms. These symptoms collectively lead to a progressive and relentless decline in the ability to perform functions of daily living, eventually leading to total incapacitation. The incidence and prevalence of AD are expected to exponentially increase with the aging of the population. Currently approved treatments, including the acetylcholinesterase inhibitors (AChEIs) donepezil, galantamine and rivastigmine, and the N-methyl-D-aspartate (NMDA) antagonist memantine, do not halt the progression of the disease, and have provided marginal therapeutic benefits. Accordingly, there is an urgent need to develop novel and effective medications for AD that go beyond AChEIs and NMDA antagonists. Modern research has focused on discovering effective disease-modifying therapies, which specifically target the pathophysiologic cascade, hoping to delay the onset of the disease and slow its progression. In this review, different pharmacological drugs and therapeutic approaches will be discussed, with an emphasis on novel therapies that are currently being investigated in clinical trials. PMID:22198801

  20. Receptor Tyrosine Kinase and Tyrosine Kinase Inhibitors

    PubMed Central

    Mirshafiey, Abbas; Ghalamfarsa, Ghasem; Asghari, Babak

    2014-01-01

    Receptor tyrosine kinases (RTKs) are essential components of signal transduction pathways that mediate cell-to-cell communication and their function as relay points for signaling pathways. They have a key role in numerous processes that control cellular proliferation and differentiation, regulate cell growth and cellular metabolism, and promote cell survival and apoptosis. Recently, the role of RTKs including TCR, FLT-3, c-Kit, c-Fms, PDGFR, ephrin, neurotrophin receptor, and TAM receptor in autoimmune disorder, especially rheumatoid arthritis and multiple sclerosis has been suggested. In multiple sclerosis pathogenesis, RTKs and their tyrosine kinase enzymes are selective important targets for tyrosine kinase inhibitor (TKI) agents. TKIs, compete with the ATP binding site of the catalytic domain of several tyrosine kinases, and act as small molecules that have a favorable safety profile in disease treatment. Up to now, the efficacy of TKIs in numerous animal models of MS has been demonstrated, but application of these drugs in human diseases should be tested in future clinical trials. PMID:25337443

  1. TNF inhibitor therapy for rheumatoid arthritis

    PubMed Central

    MA, XIXI; XU, SHENGQIAN

    2013-01-01

    Immunotherapy has markedly improved treatment outcomes in rheumatoid arthritis (RA). Tumor necrosis factor (TNF)-α antagonists, such as infliximab (IFX), etanercept (ETN), adalimumab (ADA), golimumab (GOLI) and certolizumab pegol (CZP) have been widely used for the treatment of RA. IFX provides significant, clinically relevant improvement in physical function and the quality of life, inhibits progressive joint damage and sustains improvement in the signs and symptoms of patients with RA. ETN is effective and safe for patients with RA. Combination therapy with ETN plus methotrexate (MTX) reduces disease activity, decreases total joint score progression, slows the pace of joint destruction and improves function more effectively compared to any of the monotherapies. ADA with or without MTX also relieves the signs and symptoms of RA. CZP and GOLI expand the therapeutic schedule for patients with RA. The TNF-α inhibitors have similar efficacy, but distinct clinical pharmacokinetic and -dynamic properties. The common adverse events of these TNF-α antagonists include adverse reactions, infections and injection-site reaction. Additionally, these adverse events are mostly mild or moderate and their incidence is low. Certain patients exhibit a lack of response to anti-TNF-α therapies. Some patients may discontinue the initial drug and switch to a second anti-TNF-α agent. The shortage of clinical response to one agent may not predict deficiency of response to another. This review mainly addresses the latest developments of these biological agents in the treatment of RA. PMID:24648915

  2. Ceruloplasmin Is an Endogenous Inhibitor of Myeloperoxidase*

    PubMed Central

    Chapman, Anna L. P.; Mocatta, Tessa J.; Shiva, Sruti; Seidel, Antonia; Chen, Brian; Khalilova, Irada; Paumann-Page, Martina E.; Jameson, Guy N. L.; Winterbourn, Christine C.; Kettle, Anthony J.

    2013-01-01

    Myeloperoxidase is a neutrophil enzyme that promotes oxidative stress in numerous inflammatory pathologies. It uses hydrogen peroxide to catalyze the production of strong oxidants including chlorine bleach and free radicals. A physiological defense against the inappropriate action of this enzyme has yet to be identified. We found that myeloperoxidase oxidized 75% of the ascorbate in plasma from ceruloplasmin knock-out mice, but there was no significant loss in plasma from wild type animals. When myeloperoxidase was added to human plasma it became bound to other proteins and was reversibly inhibited. Ceruloplasmin was the predominant protein associated with myeloperoxidase. When the purified proteins were mixed, they became strongly but reversibly associated. Ceruloplasmin was a potent inhibitor of purified myeloperoxidase, inhibiting production of hypochlorous acid by 50% at 25 nm. Ceruloplasmin rapidly reduced Compound I, the FeV redox intermediate of myeloperoxidase, to Compound II, which has FeIV in its heme prosthetic groups. It also prevented the fast reduction of Compound II by tyrosine. In the presence of chloride and hydrogen peroxide, ceruloplasmin converted myeloperoxidase to Compound II and slowed its conversion back to the ferric enzyme. Collectively, our results indicate that ceruloplasmin inhibits myeloperoxidase by reducing Compound I and then trapping the enzyme as inactive Compound II. We propose that ceruloplasmin should provide a protective shield against inadvertent oxidant production by myeloperoxidase during inflammation. PMID:23306200

  3. Matrilin-1 Is an Inhibitor of Neovascularization*

    PubMed Central

    Foradori, Matthew J.; Chen, Qian; Fernandez, Cecilia A.; Harper, Jay; Li, Xin; Tsang, Paul C. W.; Langer, Robert; Moses, Marsha A.

    2014-01-01

    In the course of conducting a series of studies whose goal was to discover novel endogenous angiogenesis inhibitors, we have purified matrilin-1 (MATN-1) and have demonstrated, for the first time, that it inhibits neovascularization both in vitro and in vivo. Proteins were extracted from cartilage using a 2 m NaCl, 0.01 m HEPES buffer at 4 °C, followed by concentration of the extract. The concentrate was fractionated by size exclusion chromatography, and fractions were then screened for their ability to inhibit capillary endothelial cell (EC) proliferation in vitro. Fractions containing EC inhibitory activity were pooled and further purified by cation exchange chromatography. The resulting fractions from this step were then screened to isolate the antiangiogenic activity in vitro. This activity was identified by tandem mass spectrometry as being MATN-1. Human MATN-1 was cloned and expressed in Pichia pastoris and purified to homogeneity. Purified recombinant MATN-1, along with purified native protein, was shown to inhibit angiogenesis in vivo using the chick chorioallantoic membrane assay by the inhibition of capillary EC proliferation and migration. Finally, using a MATN-1-deficient mouse, we showed that angiogenesis during fracture healing was significantly higher in MATN-1−/− mice compared with the wild type mice as demonstrated by in vivo imaging and by elevated expression of angiogenesis markers including PECAM1, VEGFR, and VE-cadherin. PMID:24692560

  4. Selective serotonin-reuptake inhibitors: an update.

    PubMed

    Masand, P S; Gupta, S

    1999-01-01

    Selective serotonin-reuptake inhibitors (SSRIs), including fluoxetine, sertraline, paroxetine, fluvoxamine, and citalopram, represent an important advance in the pharmacotherapy of mood and other disorders. They are chemically unrelated to tricyclic, heterocyclic, and other first-generation antidepressants. SSRIs are the treatment of choice for many indications, including major depression, dysthymia, panic disorder, obsessive-compulsive disorder, eating disorders, and premenstrual dysphoric disorder, because of their efficacy, good side-effect profile, tolerability, and safety in overdose, as well as patient compliance. A review of the literature was conducted using Medline and the terms "SSRIs," "fluoxetine," "sertraline," "paroxetine," "fluvoxamine," and "citalopram." Articles were limited to those published in English within the last 15 years. The search revealed that indications for antidepressants include unipolar depression, dysthymia, bipolar depression, treatment-resistant depression, depression in the medically ill, panic disorder, obsessive-compulsive disorder, eating disorders, social phobia, and premenstrual dysphoric disorder. One SSRI, fluoxetine, has demonstrated safety in pregnancy. Side effects of SSRIs include gastrointestinal disturbances, headache, sedation, insomnia, activation, weight gain, impaired memory, excessive perspiration, paresthesia, and sexual dysfunction. PMID:10471245

  5. Acetylcholinesterase inhibitors and Gulf War illnesses

    PubMed Central

    Golomb, Beatrice Alexandra

    2008-01-01

    Increasing evidence suggests excess illness in Persian Gulf War veterans (GWV) can be explained in part by exposure of GWV to organophosphate and carbamate acetylcholinesterase inhibitors (AChEis), including pyridostigmine bromide (PB), pesticides, and nerve agents. Evidence germane to the relation of AChEis to illness in GWV was assessed. Many epidemiological studies reported a link between AChEi exposure and chronic symptoms in GWV. The link is buttressed by a dose–response relation of PB pill number to chronic symptoms in GWV and by a relation between avidity of AChEi clearance and illness, based on genotypes, concentrations, and activity levels of enzymes that detoxify AChEis. Triangulating evidence derives from studies linking occupational exposure to AChEis to chronic health symptoms that mirror those of ill GWV. Illness is again linked to lower activity of AChEi detoxifying enzymes and genotypes conferring less-avid AChEi detoxification. AChEi exposure satisfies Hill's presumptive criteria for causality, suggesting this exposure may be causally linked to excess health problems in GWV. PMID:18332428

  6. [Cholinesterase inhibitor poisoning: a complicated medical challenge].

    PubMed

    Lavon, Ophir; Sagi, Ram

    2013-07-01

    Exposure to insecticides, mainly cholinesterase inhibitors, is a global problem with substantial morbidity and mortality. Risk of intoxication is increased in rural areas where there is high availability and proximity of insecticides to families and children. Neglected storage and inadequate practice lead to dangerous exposure. Strict regulations and appropriate safety measures are needed for the prevention of exposure to insecticides. Broad toxicological knowledge is necessary in order to treat organophosphate and carbamate poisoned patients. Diagnosis is not trivial, since the identity of the poison is not always apparent. Multiple exposures including organic solvents are possible. The clinical presenting can be confusing. Measurement of cholinesterase activity is mandatory in establishing the diagnosis. Prompt treatment with proper antidotes and respiratory support is indicated. Early administration of anticonvulsants may mitigate central neurologic complications. Monitoring neurologic and cardiac function is advised for rapid identification of complications and prognosis evaluation. Meticulous preparedness of health care providers for insecticide poisoning is needed from the pre-hospital phase to emergency departments and the different hospital wards. PMID:23957084

  7. Human neutrophil elastase inhibitors in innate and adaptive immunity.

    PubMed

    Fitch, P M; Roghanian, A; Howie, S E M; Sallenave, J-M

    2006-04-01

    Recent evidence shows that human neutrophil elastase inhibitors can be synthesized locally at mucosal sites. In addition to efficiently targeting bacterial and host enzymes, they can be released in the interstitium and in the lumen of mucosa, where they have been shown to have antimicrobial activities, and to activate innate immune responses. This review will address more particularly the pleiotropic functions of low-molecular-mass neutrophil elastase inhibitors [SLPI (secretory leucocyte proteinase inhibitor) and elafin] and, more specifically, their role in the development of the adaptive immune response. PMID:16545094

  8. Design and Synthesis of Potent, Selective Inhibitors of Matriptase

    PubMed Central

    2012-01-01

    Matriptase is a member of the type II transmembrane serine protease family. Several studies have reported deregulated matriptase expression in several types of epithelial cancers, suggesting that matriptase constitutes a potential target for cancer therapy. We report herein a new series of slow, tight-binding inhibitors of matriptase, which mimic the P1–P4 substrate recognition sequence of the enzyme. Preliminary structure–activity relationships indicate that this benzothiazole-containing RQAR-peptidomimetic is a very potent inhibitor and possesses a good selectivity for matriptase versus other serine proteases. A molecular model was generated to elucidate the key contacts between inhibitor 1 and matriptase. PMID:24900505

  9. Development of novel proteasome inhibitors based on phthalazinone scaffold.

    PubMed

    Yang, Lingfei; Wang, Wei; Sun, Qi; Xu, Fengrong; Niu, Yan; Wang, Chao; Liang, Lei; Xu, Ping

    2016-06-15

    In this study we designed a series of proteasome inhibitors using pyridazinone as initial scaffold, and extended the structure with rational design by computer aided drug design (CADD). Two different synthetic routes were explored and the biological evaluation of the phthalazinone derivatives was investigated. Most importantly, electron positive triphenylphosphine group was first introduced in the structure of proteasome inhibitors and potent inhibition was achieved. As 6c was the most potent inhibitor of proteasome, we examined the structure-activity relationship (SAR) of 6c analogs. PMID:27158142

  10. VEGF receptor kinase inhibitors: phthalazines, anthranilamides and related structures.

    PubMed

    Dumas, Jacques; Dixon, Julie A

    2005-06-01

    Inhibition of vascular endothelial growth factor receptor (VEGFR) signalling, using either antibodies or small molecule inhibitors of the VEGFR kinase domain, has become a major area of research in oncology. The phthalazine PTK787/ZK222584, first published in the literature in 1998, is one of the most advanced VEGFR inhibitors in the clinic. This paper provides an update on the patenting activity related to the phthalazine class. In addition, newer kinase inhibitor pharmacophores derived from this class (e.g., anthranilamides) will be reviewed. PMID:20141503

  11. Physical and psychosocial challenges in adult hemophilia patients with inhibitors

    PubMed Central

    duTreil, Sue

    2014-01-01

    Numerous challenges confront adult hemophilia patients with inhibitors, including difficulty in controlling bleeding episodes, deterioration of joints, arthritic pain, physical disability, emotional turmoil, and social issues. High-intensity treatment regimens often used in the treatment of patients with inhibitors also impose significant scheduling, economic, and emotional demands on patients and their families or primary caregivers. A comprehensive multidisciplinary assessment of the physical, emotional, and social status of adult hemophilia patients with inhibitors is essential for the development of treatment strategies that can be individualized to address the complex needs of these patients. PMID:25093002

  12. Towards a Unified Model of RAF Inhibitor Resistance

    PubMed Central

    Solit, David B.; Rosen, Neal

    2016-01-01

    Summary ATP-competitive RAF inhibitors elicit profound but often temporary antitumor responses in patients with BRAF-mutant melanoma. Analysis of tumor samples collected at the time of disease progression indicates that alterations within the extracellular signal-regulated kinase (ERK) pathway that result in reactivation of ERK signaling are present in most patients. Mutations in the phosphoinositide 3-kinase/AKT pathway that enhance the adaptive response to RAF inhibitors also contribute to RAF inhibitor resistance in a subset of patients. PMID:24402945

  13. Chlorine's effects on triazole inhibitor layers on copper

    SciTech Connect

    Holm, R.; Over, J.; Wittig, M.; Minnich, R.; Berg, D. ); Eickmans, J.; Holtkamp, D. ); Meyer, K.; Benninghoven, A. )

    1994-05-01

    The triazole film on copper (Cu) is the result of a dynamic equilibrium between the inhibitor film formation and the corrosion reaction of the underlying metal; therefore, it can be penetrated by water and chlorine molecules, as well as by protons, chloride, and metallic ions. This penetration results in Cu corrosion and is immediately detected through electrochemistry. Degradation of the inhibitor film, which takes some time, can best be observed by surface analysis. Once film degradation has started, penetration is enhanced, and both processes lead to excessive Cu corrosion rates. The effect of this two-step interaction between chlorine and two triazole inhibitors now primarily in use in the industry was investigated.

  14. Inhibitors – cellular aspects and novel approaches for tolerance

    PubMed Central

    SCOTT, D. W.

    2014-01-01

    Summary The immune response against therapeutic clotting factors VIII and IX (FVIII and FIX) is a major adverse event that can effectively thwart their effectiveness in correcting bleeding disorders. Thus, a significant number of haemophilia patients form antibodies, called inhibitors, which neutralize the procoagulant functions of therapeutic cofactors FVIII (haemophilia A) or FIX (haemophilia B). Understanding the cellular and molecular aspects of inhibitor formation is critical to designing tolerogenic therapies for clinical use. This review will focus on the basis of the immune response to FVIII, in particular, and will discuss emerging efforts to not only reduce immunogenicity but also to prevent and/or reverse inhibitor formation. PMID:24762281

  15. Acalabrutinib (ACP-196): a selective second-generation BTK inhibitor.

    PubMed

    Wu, Jingjing; Zhang, Mingzhi; Liu, Delong

    2016-01-01

    More and more targeted agents become available for B cell malignancies with increasing precision and potency. The first-in-class Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, has been in clinical use for the treatment of chronic lymphocytic leukemia, mantle cell lymphoma, and Waldenstrom's macroglobulinemia. More selective BTK inhibitors (ACP-196, ONO/GS-4059, BGB-3111, CC-292) are being explored. Acalabrutinib (ACP-196) is a novel irreversible second-generation BTK inhibitor that was shown to be more potent and selective than ibrutinib. This review summarized the preclinical research and clinical data of acalabrutinib. PMID:26957112

  16. Primary Structure of a Trypsin Inhibitor (Copaifera langsdorffii Trypsin Inhibitor-1) Obtained from C. langsdorffii Seeds.

    PubMed

    Silva, José A; Pompeu, Dávia G; Smolka, Marcus B; Gozzo, Fabio C; Comar, Moacyr; Eberlin, Marcos N; Granjeiro, Paulo A; Marangoni, Sérgio

    2015-09-01

    In this study, the aim was to determine the complete sequence of the Copaifera langsdorffii trypsin inhibitor (CTI)-1 using 2-dimensional (2D)-PAGE, matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF), and quadrupole time-of-flight (QTOF) spectrometry. Spots A (CTI-1) and F (CTI-2) were submitted to enzymatic digestions with trypsin, SV8, and clostripain. The accurate mass of the peptide obtained from each digest was determined by mass spectrometry (MS) using MALDI-TOF. The most abundant peptides were purified and sequenced in a liquid chromatograph connected to an electrospray ionization-QTOF MS. When the purified trypsin inhibitor was submitted to 2D electrophoresis, different spots were observed, suggesting that the protein is composed of 2 subunits with microheterogeneity. Isoelectric points of 8.0, 8.5, and 9.0 were determined for the 11 kDa subunit and of 4.7, 4.6, and 4.3 for the 9 kDa subunit. The primary structure of CTI-1, determined from the mass of the peptide of the enzymatic digestions and the sequence obtained by MS, indicated 180 shared amino acid residues and a high degree of similarity with other Kunitz (KTI)-type inhibitors. The peptide also contained an Arg residue at the reactive site position. Its 3-dimensional structure revealed that this is because the structural discrepancies do not affect the canonical conformation of the reactive loop of the peptide. Results demonstrate that a detailed investigation of the structural particularities of CTI-1 could provide a better understanding of the mechanism of action of these proteins, as well as clarify its biologic function in the seeds. CTI-1 belongs to the KTI family and is composed of 2 polypeptide chains and only 1 disulfide bridge. PMID:26207098

  17. Primary Structure of a Trypsin Inhibitor (Copaifera langsdorffii Trypsin Inhibitor-1) Obtained from C. langsdorffii Seeds

    PubMed Central

    Silva, José A.; Pompeu, Dávia G.; Smolka, Marcus B.; Gozzo, Fabio C.; Comar, Moacyr; Eberlin, Marcos N.; Marangoni, Sérgio

    2015-01-01

    In this study, the aim was to determine the complete sequence of the Copaifera langsdorffii trypsin inhibitor (CTI)-1 using 2-dimensional (2D)-PAGE, matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF), and quadrupole time-of-flight (QTOF) spectrometry. Spots A (CTI-1) and F (CTI-2) were submitted to enzymatic digestions with trypsin, SV8, and clostripain. The accurate mass of the peptide obtained from each digest was determined by mass spectrometry (MS) using MALDI-TOF. The most abundant peptides were purified and sequenced in a liquid chromatograph connected to an electrospray ionization-QTOF MS. When the purified trypsin inhibitor was submitted to 2D electrophoresis, different spots were observed, suggesting that the protein is composed of 2 subunits with microheterogeneity. Isoelectric points of 8.0, 8.5, and 9.0 were determined for the 11 kDa subunit and of 4.7, 4.6, and 4.3 for the 9 kDa subunit. The primary structure of CTI-1, determined from the mass of the peptide of the enzymatic digestions and the sequence obtained by MS, indicated 180 shared amino acid residues and a high degree of similarity with other Kunitz (KTI)-type inhibitors. The peptide also contained an Arg residue at the reactive site position. Its 3-dimensional structure revealed that this is because the structural discrepancies do not affect the canonical conformation of the reactive loop of the peptide. Results demonstrate that a detailed investigation of the structural particularities of CTI-1 could provide a better understanding of the mechanism of action of these proteins, as well as clarify its biologic function in the seeds. CTI-1 belongs to the KTI family and is composed of 2 polypeptide chains and only 1 disulfide bridge. PMID:26207098

  18. CCT241533 is a potent and selective inhibitor of CHK2 which potentiates the cytotoxicity of PARP inhibitors

    PubMed Central

    Anderson, Victoria E; Walton, Michael I; Eve, Paul D; Boxall, Katherine J; Antoni, Laurent; Caldwell, John J; Pearl, Laurence H; Oliver, Antony W; Collins, Ian; Garrett, Michelle D

    2016-01-01

    CHK2 is a checkpoint kinase involved in the ATM-mediated response to double strand DNA breaks. Its potential as a drug target is still unclear but inhibitors of CHK2 may increase the efficacy of genotoxic cancer therapies in a p53 mutant background by eliminating one of the checkpoints or DNA repair pathways contributing to cellular resistance. We report here the identification and characterization of a novel CHK2 kinase inhibitor, CCT241533. X-ray crystallography confirmed that CCT241533 bound to CHK2 in the ATP pocket. This compound inhibits CHK2 with an IC50 of 3 nM and shows minimal cross reactivity against a panel of kinases at 1 μM. CCT241533 blocked CHK2 activity in human tumor cell lines in response to DNA damage, as demonstrated by inhibition of CHK2 autophosphorylation at S516, band-shift mobility changes and HDMX degradation. CCT241533 did not potentiate the cytotoxicity of a selection of genotoxic agents in several cell lines. However, this compound significantly potentiates the cytotoxicity of two structurally distinct Poly (ADP-ribose) polymerase (PARP) inhibitors. Clear induction of the pS516 CHK2 signal was seen with a PARP inhibitor alone and this activation was abolished by CCT241533, implying that the potentiation of PARP inhibitor cell killing by CCT241533 was due to inhibition of CHK2. Consequently CHK2 inhibitors may have therapeutic activity in combination with PARP inhibitors. PMID:21239475

  19. The Aminopeptidase Inhibitor CHR-2863 Is an Orally Bioavailable Inhibitor of Murine Malaria

    PubMed Central

    Skinner-Adams, Tina S.; Peatey, Christopher L.; Anderson, Karen; Trenholme, Katharine R.; Krige, David; Brown, Christopher L.; Stack, Colin; Nsangou, Desire M. M.; Mathews, Rency T.; Thivierge, Karine; Dalton, John P.

    2012-01-01

    Malaria remains a significant risk in many areas of the world, with resistance to the current antimalarial pharmacopeia an ever-increasing problem. The M1 alanine aminopeptidase (PfM1AAP) and M17 leucine aminopeptidase (PfM17LAP) are believed to play a role in the terminal stages of digestion of host hemoglobin and thereby generate a pool of free amino acids that are essential for parasite growth and development. Here, we show that an orally bioavailable aminopeptidase inhibitor, CHR-2863, is efficacious against murine malaria. PMID:22450967

  20. Growth Morphologies of Wax in the Presence Kinetic Inhibitors

    NASA Astrophysics Data System (ADS)

    Tetervak, Alexander; Hutter, Jeffrey

    2004-03-01

    Kinetic inhibitors are molecules that alter crystal growth rates and morphologies by adsorbing to growth faces. Such species are used in many commercial processes to control microsctructure, and in other cases to prevent crystallization altogether. Despite their importance, the details of their mechanisms are largely unverified. We are studying the effects of such inhibitors on the crystallization of normal alkanes from solution. We find that inhibitors drastically alter the crystal morphology. As in similar systems, we see ``burst growth,'' in which newly formed solid is able to grow faster due to lower inhibitor coverage. Our experiments show several growth morphologies as a function of conditions: a tree-like structure that in some cases forms bands, and spherulites with characteristics very similar to those seen in polymers. Here, we characterize the front morphology as a function of these conditions and compare the results to numerical models that capture the essential growth behavior.