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Sample records for ii dehydroquinase inhibitors

  1. Comparative binding energy COMBINE analysis for understanding the binding determinants of type II dehydroquinase inhibitors.

    PubMed

    Peón, Antonio; Coderch, Claire; Gago, Federico; González-Bello, Concepción

    2013-05-01

    Herein we report comparative binding energy (COMBINE) analyses to derive quantitative structure-activity relationship (QSAR) models that help rationalize the determinants of binding affinity for inhibitors of type II dehydroquinase (DHQ2), the third enzyme of the shikimic acid pathway. Independent COMBINE models were derived for Helicobacter pylori and Mycobacterium tuberculosis DHQ2, which is an essential enzyme in both these pathogenic bacteria that has no counterpart in human cells. These studies quantify the importance of the hydrogen bonding interactions between the ligands and the water molecule involved in the DHQ2 reaction mechanism. They also highlight important differences in the ligand interactions with the interface pocket close to the active site that could provide guides for future inhibitor design.

  2. Type II dehydroquinase: molecular replacement with many copies

    PubMed Central

    Stewart, Kirsty Anne; Robinson, David Alexander; Lapthorn, Adrian Jonathan

    2008-01-01

    Type II dehydroquinase is a small (150-amino-acid) protein which in solution packs together to form a dodecamer with 23 cubic symmetry. In crystals of this protein the symmetry of the biological unit can be coincident with the crystallographic symmetry, giving rise to cubic crystal forms with a single monomer in the asymmetric unit. In crystals where this is not the case, multiple copies of the monomer are present, giving rise to significant and often confusing noncrystallographic symmetry in low-symmetry crystal systems. These different crystal forms pose a variety of challenges for solution by molecular replacement. Three examples of structure solutions, including a highly unusual triclinic crystal form with 16 dodecamers (192 monomers) in the unit cell, are described. Four commonly used molecular-replacement packages are assessed against two of these examples, one of high symmetry and the other of low symmetry; this study highlights how program performance can vary significantly depending on the given problem. In addition, the final refined structure of the 16-dodecamer triclinic crystal form is analysed and shown not to be a superlattice structure, but rather an F-centred cubic crystal with frustrated crystallographic symmetry. PMID:18094474

  3. Mechanistic insight into the reaction catalysed by bacterial type II dehydroquinases.

    PubMed

    Coderch, Claire; Lence, Emilio; Peón, Antonio; Lamb, Heather; Hawkins, Alastair R; Gago, Federico; González-Bello, Concepción

    2014-03-15

    DHQ2 (type II dehydroquinase), which is an essential enzyme in Helicobacter pylori and Mycobacterium tuberculosis and does not have any counterpart in humans, is recognized to be an attractive target for the development of new antibacterial agents. Computational and biochemical studies that help understand in atomic detail the catalytic mechanism of these bacterial enzymes are reported in the present paper. A previously unknown key role of certain conserved residues of these enzymes, as well as the structural changes responsible for triggering the release of the product from the active site, were identified. Asp89*/Asp88* from a neighbouring enzyme subunit proved to be the residue responsible for the deprotonation of the essential tyrosine to afford the catalytic tyrosinate, which triggers the enzymatic process. The essentiality of this residue is supported by results from site-directed mutagenesis. For H. pylori DHQ2, this reaction takes place through the assistance of a water molecule, whereas for M. tuberculosis DHQ2, the tyrosine is directly deprotonated by the aspartate residue. The participation of a water molecule in this deprotonation reaction is supported by solvent isotope effects and proton inventory studies. MD simulation studies provide details of the required motions for the catalytic turnover, which provides a complete overview of the catalytic cycle. The product is expelled from the active site by the essential arginine residue and after a large conformational change of a loop containing two conserved arginine residues (Arg109/Arg108 and Arg113/Arg112), which reveals a previously unknown key role for these residues. The present study highlights the key role of the aspartate residue whose blockage could be useful in the rational design of inhibitors and the mechanistic differences between both enzymes.

  4. A new photosystem II electron transfer inhibitor from Sorghum bicolor.

    PubMed

    Rimando, A M; Dayan, F E; Czarnota, M A; Weston, L A; Duke, S O

    1998-07-01

    Our study of the mechanism(s) by which sorgoleone (1) acts as a photosystem II (PS II) inhibitor led to the isolation of a new benzoquinone derivative, 2-hydroxy-5-ethoxy-3-[(Z,Z)-8',11', 14'-pentadecatriene]-rho-benzoquinone (2), from the root exudate of sorghum. The structure of 2, which is being given the name 5-ethoxy-sorgoleone, was determined by spectroscopic means. A methoxy derivative (3) of 1 was also prepared. Both 2 and 3 caused a reduction in oxygen evolution by thylakoid membranes and induced variable chlorophyll fluorescence. These compounds, however, were less active inhibitors of PS II than 1.

  5. DNA methyltransferase inhibitor CDA-II inhibits myogenic differentiation

    SciTech Connect

    Chen, Zirong; Jin, Guorong; Lin, Shuibin; Lin, Xiumei; Gu, Yumei; Zhu, Yujuan; Hu, Chengbin; Zhang, Qingjiong; Wu, Lizi; Shen, Huangxuan

    2012-06-08

    Highlights: Black-Right-Pointing-Pointer CDA-II inhibits myogenic differentiation in a dose-dependent manner. Black-Right-Pointing-Pointer CDA-II repressed expression of muscle transcription factors and structural proteins. Black-Right-Pointing-Pointer CDA-II inhibited proliferation and migration of C2C12 myoblasts. -- Abstract: CDA-II (cell differentiation agent II), isolated from healthy human urine, is a DNA methyltransferase inhibitor. Previous studies indicated that CDA-II played important roles in the regulation of cell growth and certain differentiation processes. However, it has not been determined whether CDA-II affects skeletal myogenesis. In this study, we investigated effects of CDA-II treatment on skeletal muscle progenitor cell differentiation, migration and proliferation. We found that CDA-II blocked differentiation of murine myoblasts C2C12 in a dose-dependent manner. CDA-II repressed expression of muscle transcription factors, such as Myogenin and Mef2c, and structural proteins, such as myosin heavy chain (Myh3), light chain (Mylpf) and MCK. Moreover, CDA-II inhibited C1C12 cell migration and proliferation. Thus, our data provide the first evidence that CDA-II inhibits growth and differentiation of muscle progenitor cells, suggesting that the use of CDA-II might affect skeletal muscle functions.

  6. Blebbistatin, a myosin II inhibitor, is photoinactivated by blue light.

    PubMed

    Sakamoto, Takeshi; Limouze, John; Combs, Christian A; Straight, Aaron F; Sellers, James R

    2005-01-18

    Blebbistatin is a small molecule inhibitor discovered in a screen for inhibitors of nonmuscle myosin IIA. Blebbistatin inhibits the actin-activated MgATPase activity and in vitro motility of class II myosins. In cells, it has been shown to inhibit contraction of the cytokinetic ring. Blebbistatin has some photochemical properties that may affect its behavior in cells. In particular, we have found that exposure to light at wavelengths below 488 nm rapidly inactivates the inhibitory action of blebbistatin using the in vitro motility of myosin as an assay. In addition, the inhibition of cytokinetic ring contraction can be reversed by exposure of the cells to blue light. This property may be useful in locally reversing the action of blebbistatin treatment in a cell. However, caution should be exercised as free radicals may be produced upon irradiation of blebbistatin that could result in cell damage.

  7. Pyrroloquinolinone-based dual topoisomerase I/II inhibitor.

    PubMed

    Dalla Via, Lisa; Marzaro, Giovanni; Ferrarese, Alessandro; Gia, Ornella; Chilin, Adriana

    2014-04-22

    A new series of pyrroloquinolinones bearing different alkylamino side chains were synthesized and evaluated as cytotoxic compounds against three different human tumor cell lines (HeLa, HL-60 and A431). Some compounds showed interesting antiproliferative activity, in particular against A431 cells. The compounds were tested for their ability to counteract topoisomerase II relaxation activity and the most interesting one (3c) was tested also against topoisomerase I, resulting a dual inhibitor. The molecular interactions between 3c and the intracellular targets were finally investigated through molecular modeling simulations.

  8. Proposal of Dual Inhibitor Targeting ATPase Domains of Topoisomerase II and Heat Shock Protein 90

    PubMed Central

    Jun, Kyu-Yeon; Kwon, Youngjoo

    2016-01-01

    There is a conserved ATPase domain in topoisomerase II (topo II) and heat shock protein 90 (Hsp90) which belong to the GHKL (gyrase, Hsp90, histidine kinase, and MutL) family. The inhibitors that target each of topo II and Hsp90 are intensively studied as anti-cancer drugs since they play very important roles in cell proliferation and survival. Therefore the development of dual targeting anti-cancer drugs for topo II and Hsp90 is suggested to be a promising area. The topo II and Hsp90 inhibitors, known to bind to their ATP binding site, were searched. All the inhibitors investigated were docked to both topo II and Hsp90. Four candidate compounds as possible dual inhibitors were selected by analyzing the molecular docking study. The pharmacophore model of dual inhibitors for topo II and Hsp90 were generated and the design of novel dual inhibitor was proposed. PMID:27582553

  9. 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

  10. Structural and functional characteristics of plant proteinase inhibitor-II (PI-II) family.

    PubMed

    Rehman, Shazia; Aziz, Ejaz; Akhtar, Wasim; Ilyas, Muhammad; Mahmood, Tariq

    2017-02-09

    Plant proteinase inhibitor-II (PI-II) proteins are one of the promising defensive proteins that helped the plants to resist against different kinds of unfavorable conditions. Different roles for PI-II have been suggested such as regulation of endogenous proteases, modulation of plant growth and developmental processes and mediating stress responses. The basic knowledge on genetic and molecular diversity of these proteins has provided significant insight into their gene structure and evolutionary relationships in various members of this family. Phylogenetic comparisons of these family genes in different plants suggested that the high rate of retention of gene duplication and inhibitory domain multiplication may have resulted in the expansion and functional diversification of these proteins. Currently, a large number of transgenic plants expressing PI-II genes are being developed for enhancing the defensive capabilities against insects, bacteria and pathogenic fungi. Much emphasis is yet to be given to exploit this ever expanding repertoire of genes for improving abiotic stress resistance in transgenic crops. This review presents an overview about the current knowledge on PI-II family genes, their multifunctional role in plant defense and physiology with their potential applications in biotechnology.

  11. Materials Evaluation. Part II. Development of Corrosion Inhibitors.

    DTIC Science & Technology

    1979-09-01

    and Identify by block number) A borax -nitrite based inhibitor has been developed for incorporation into the Air Force Rinse Facility at MacDill Air...Block 20 inhibitors has been tested and a borax -nitrite based formulation developed which inhibits the corrosion of several ferrous and nonferrous...alternatives to chromates, one such alternative being a borax -nitrite based inhibitor. The value of borax nitrite as a corrosion inhibitor has long been

  12. Docking studies of sulphamate inhibitors of estrone sulphatase in human carbonic anhydrase II.

    PubMed

    Vicker, Nigel; Ho, Yaikat; Robinson, James; Woo, Lawrence L W; Purohit, Atul; Reed, Michael J; Potter, Barry V L

    2003-03-10

    We describe the docking of selected steroidal and non-steroidal estrone sulphatase inhibitors, including the Phase I clinical trial candidate 667COUMATE (6), into the active site of human carbonic anhydrase II (hCA II). The docking scores are compared with the inhibition of hCA II and show good correlation with biological activity.

  13. Carbonic anhydrase II-induced selection of inhibitors from a dynamic combinatorial library of Schiff's bases.

    PubMed

    Nasr, Gihane; Petit, Eddy; Supuran, Claudiu T; Winum, Jean-Yves; Barboiu, Mihail

    2009-11-01

    A dynamic combinatorial library (DCL) has been generated under thermodynamic control by using the aminocarbonyl/imine interconversion as reversible chemistry, combined with non-covalent binding within the active site of the metalloenzyme human carbonic anhydrase II (hCA II, EC 4.2.1.1). The high affinity of hCA II isozyme towards some sulfonamide inhibitors obtained here was used to select from the dynamic library specific inhibitors of this isoform. These results point out to the possibility of identifying sulfonamide amplified compounds presenting potent inhibition and high yield of formation in the presence of the isoform(s) towards which the inhibitors were designed.

  14. SphK1 inhibitor II (SKI-II) inhibits acute myelogenous leukemia cell growth in vitro and in vivo.

    PubMed

    Yang, Li; Weng, Wei; Sun, Zhi-Xin; Fu, Xian-Jie; Ma, Jun; Zhuang, Wen-Fang

    2015-05-15

    Previous studies have identified sphingosine kinase 1 (SphK1) as a potential drug target for treatment of acute myeloid leukemia (AML). In the current study, we investigated the potential anti-leukemic activity of a novel and specific SphK1 inhibitor, SKI-II. We demonstrated that SKI-II inhibited growth and survival of human AML cell lines (HL-60 and U937 cells). SKI-II was more efficient than two known SphK1 inhibitors SK1-I and FTY720 in inhibiting AML cells. Meanwhile, it induced dramatic apoptosis in above AML cells, and the cytotoxicity by SKI-II was almost reversed by the general caspase inhibitor z-VAD-fmk. SKI-II treatment inhibited SphK1 activation, and concomitantly increased level of sphingosine-1-phosphate (S1P) precursor ceramide in AML cells. Conversely, exogenously-added S1P protected against SKI-II-induced cytotoxicity, while cell permeable short-chain ceramide (C6) aggravated SKI-II's lethality against AML cells. Notably, SKI-II induced potent apoptotic death in primary human AML cells, but was generally safe to the human peripheral blood mononuclear cells (PBMCs) isolated from healthy donors. In vivo, SKI-II administration suppressed growth of U937 leukemic xenograft tumors in severe combined immunodeficient (SCID) mice. These results suggest that SKI-II might be further investigated as a promising anti-AML agent.

  15. Type II topoisomerases--inhibitors, repair mechanisms and mutations.

    PubMed

    Heisig, Peter

    2009-11-01

    Type II topoisomerases are ubiquitous enzymes that play an essential role in the control of replicative DNA synthesis and share structural and functional homology among different prokaryotic and eukaryotic organisms. Antibacterial fluoroquinolones target prokaryotic topoisomerases at concentrations 100- to 1000-fold lower than mammalian enzymes, the preferred targets of anticancer drugs such as etoposide. The mechanisms of action of both of these types of inhibitors involve the fixation of an intermediate reaction step, where the enzyme is covalently bound to an enzyme-mediated DNA double-strand break (DSB). The resulting ternary drug-enzyme-DNA complexes can then be converted to cleavage complexes that block further movement of the DNA replication fork, subsequently inducing stress responses. In haploid prokaryotic cells, stress responses include error-free and error-prone DNA damage repair pathways, such as homologous recombination and translesion synthesis, respectively. The latter can result in the acquisition of point mutations. Diploid mammalian cells are assumed to preferentially use recombination mechanisms for the repair of DSBs, an example of which, non-homologous end joining, is a major error-prone repair mechanism associated with an increased frequency of detectable small deletions, insertions and translocations. However, results obtained from safety testing of novel fluoroquinolones at high concentrations indicate that point mutations may also occur in mammalian cells. Recent data provide evidence for translesion synthesis catalysed by error-prone repair polymerases as a damage-tolerance repair mechanism of DSBs in eukaryotic cells. This paper discusses possible roles of different mechanisms for the repair of DSBs operating in both eukaryotic and prokaryotic cells that result in recombinational rearrangements, deletions/insertions as well as point mutations.

  16. Efficacy of the small molecule inhibitor of Lipid II BAS00127538 against Acinetobacter baumannii

    PubMed Central

    de Leeuw, Erik PH

    2014-01-01

    Objective To test the activity of a small molecule compound that targets Lipid II against Acinetobacter baumannii. Methods Susceptibility to small molecule Lipid II inhibitor BAS00127538 was assessed using carbapenem- and colistin-resistant clinical isolates of A. baumannii. In addition, synergy between colisitin and this compound was assessed. Results Small molecule Lipid II inhibitor BAS00127538 potently acts against A. baumannii and acts synergistically with colistin. Conclusion For the first time, a compound that targets Lipid II is described that acts against multi-drug resistant isolates of A. baumannii. The synergy with colistin warrants further lead development of BAS00127538. PMID:25143710

  17. Design of highly potent urea-based, exosite-binding inhibitors selective for glutamate carboxypeptidase II.

    PubMed

    Tykvart, Jan; Schimer, Jiří; Jančařík, Andrej; Bařinková, Jitka; Navrátil, Václav; Starková, Jana; Šrámková, Karolína; Konvalinka, Jan; Majer, Pavel; Šácha, Pavel

    2015-05-28

    We present here a structure-aided design of inhibitors targeting the active site as well as exosites of glutamate carboxypeptidase II (GCPII), a prostate cancer marker, preparing potent and selective inhibitors that are more than 1000-fold more active toward GCPII than its closest human homologue, glutamate carboxypeptidase III (GCPIII). Additionally, we demonstrate that the prepared inhibitor conjugate can be used for sensitive and selective imaging of GCPII in mammalian cells.

  18. Virtual screening and optimization of Type II inhibitors of JAK2 from a natural product library.

    PubMed

    Ma, Dik-Lung; Chan, Daniel Shiu-Hin; Wei, Guo; Zhong, Hai-Jing; Yang, Hui; Leung, Lai To; Gullen, Elizabeth A; Chiu, Pauline; Cheng, Yung-Chi; Leung, Chung-Hang

    2014-11-21

    Amentoflavone has been identified as a JAK2 inhibitor by structure-based virtual screening of a natural product library. In silico optimization using the DOLPHIN model yielded analogues with enhanced potency against JAK2 activity and HCV activity in cellulo. Molecular modeling and kinetic experiments suggested that the analogues may function as Type II inhibitors of JAK2.

  19. Inhibition of dihydroceramide desaturase activity by the sphingosine kinase inhibitor SKI II.

    PubMed

    Cingolani, Francesca; Casasampere, Mireia; Sanllehí, Pol; Casas, Josefina; Bujons, Jordi; Fabrias, Gemma

    2014-08-01

    Sphingosine kinase inhibitor (SKI) II has been reported as a dual inhibitor of sphingosine kinases (SKs) 1 and 2 and has been extensively used to prove the involvement of SKs and sphingosine-1-phosphate (S1P) in cellular processes. Dihydroceramide desaturase (Des1), the last enzyme in the de novo synthesis of ceramide (Cer), regulates the balance between dihydroceramides (dhCers) and Cers. Both SKs and Des1 have interest as therapeutic targets. Here we show that SKI II is a noncompetitive inhibitor (Ki = 0.3 μM) of Des1 activity with effect also in intact cells without modifying Des1 protein levels. Molecular modeling studies support that the SKI II-induced decrease in Des1 activity could result from inhibition of NADH-cytochrome b5 reductase. SKI II, but not the SK1-specific inhibitor PF-543, provoked a remarkable accumulation of dhCers and their metabolites, while both SKI II and PF-543 reduced S1P to almost undetectable levels. SKI II, but not PF543, reduced cell proliferation with accumulation of cells in the G0/G1 phase. SKI II, but not PF543, induced autophagy. These overall findings should be taken into account when using SKI II as a pharmacological tool, as some of the effects attributed to decreased S1P may actually be caused by augmented dhCers and/or their metabolites.

  20. Catalytic inhibitors of DNA topoisomerase II suppress the androgen receptor signaling and prostate cancer progression

    PubMed Central

    Li, Haolong; Xie, Ning; Gleave, Martin E.; Dong, Xuesen

    2015-01-01

    Although the new generation of androgen receptor (AR) antagonists like enzalutamide (ENZ) prolong survival of metastatic castration-resistant prostate cancer (CRPC), AR-driven tumors eventually recur indicating that additional therapies are required to fully block AR function. Since DNA topoisomerase II (Topo II) was demonstrated to be essential for AR to initiate gene transcription, this study tested whether catalytic inhibitors of Topo II can block AR signaling and suppress ENZ-resistant CRPC growth. Using multiple prostate cancer cell lines, we showed that catalytic Topo II inhibitors, ICRF187 and ICRF193 inhibited transcription activities of the wild-type AR, mutant ARs (F876L and W741C) and the AR-V7 splice variant. ICRF187 and ICRF193 decreased AR recruitment to target promoters and reduced AR nuclear localization. Both ICRF187 and ICRF193 also inhibited cell proliferation and delayed cell cycling at the G2/M phase. ICRF187 inhibited tumor growth of castration-resistant LNCaP and 22RV1 xenografts as well as ENZ-resistant MR49F xenografts. We conclude that catalytic Topo II inhibitors can block AR signaling and inhibit tumor growth of CRPC xenografts, identifying a potential co-targeting approach using these inhibitors in combination with AR pathway inhibitors in CRPC. PMID:26009876

  1. Photobleaching reveals complex effects of inhibitors on transcribing RNA polymerase II in living cells

    SciTech Connect

    Fromaget, Maud; Cook, Peter R. . E-mail: peter.cook@path.ox.ac.uk

    2007-08-15

    RNA polymerase II transcribes most eukaryotic genes. Photobleaching studies have revealed that living Chinese hamster ovary cells expressing the catalytic subunit of the polymerase tagged with the green fluorescent protein contain a large rapidly exchanging pool of enzyme, plus a smaller engaged fraction; genetic complementation shows this tagged polymerase to be fully functional. We investigated how transcriptional inhibitors - some of which are used therapeutically - affect the engaged fraction in living cells using fluorescence loss in photobleaching; all were used at concentrations that have reversible effects. Various kinase inhibitors (roscovitine, DRB, KM05283, alsterpaullone, isoquinolinesulfonamide derivatives H-7, H-8, H-89, H-9), proteasomal inhibitors (lactacystin, MG132), and an anti-tumour agent (cisplatin) all reduced the engaged fraction; an intercalator (actinomycin D), two histone deacetylase inhibitors (trichostatin A, sodium butyrate), and irradiation with ultra-violet light all increased it. The polymerase proves to be both a sensitive sensor and effector of the response to these inhibitors.

  2. Human Multiple Myeloma Cells Are Sensitized to Topoisomerase II Inhibitors by CRM1 Inhibition

    PubMed Central

    Turner, Joel G.; Marchion, Douglas C.; Dawson, Jana L.; Emmons, Michael F.; Hazlehurst, Lori A.; Washausen, Peter; Sullivan, Daniel M.

    2009-01-01

    Topoisomerase IIα (topo IIα) is exported from the nucleus of human myeloma cells by a CRM1-dependent mechanism at cellular densities similar to those found in patient bone marrow. When topo IIα is trafficked to the cytoplasm, it is not in contact with the DNA; thus topo IIα inhibitors are unable to induce DNA-cleavable complexes and cell death. Using a CRM1 inhibitor or a CRM1-specific small interfering RNA (siRNA), we were able to block nuclear export of topo IIα as shown by immunofluorescence microscopy. Human myeloma cell lines and patient myeloma cells isolated from bone marrow were treated with a CRM1 inhibitor or CRM1-specific siRNA and exposed to doxorubicin or etoposide (VP-16) at high cell densities. CRM1-treated cell lines or myeloma patient cells were fourfold more sensitive to topo II poisons, as determined by activated caspase assay. Normal cells were not significantly affected by CRM1-topo II combination treatment. Cell death was correlated with increased DNA double-strand breaks as shown by the comet assay. Band depletion assays of CRM1 inhibitor-exposed myeloma cells demonstrated increased topo IIα covalently bound to DNA. Topo IIα knockdown by a topo IIα-specific siRNA abrogated the CRM1-topo II therapy synergistic effect. These results suggest that blocking topo IIα nuclear export sensitizes myeloma cells to topo II inhibitors. This method of sensitizing myeloma cells suggests a new therapeutic approach to multiple myeloma. PMID:19690141

  3. Different effects of eubacterial and eukaryotic DNA topoisomerase II inhibitors on chloroplasts ofEuglena gracilis

    NASA Astrophysics Data System (ADS)

    Krajčovič, Juraj; Ebringer, Libor

    1990-03-01

    Inhibitors of eubacterial and eukaryotic DNA topoisomerases type II exhibited different effects on chloroplasts of the flagellateEuglena gracilis. Antibacterial agents (cinoxacin, nalidixic and oxolinic acids, ciprofloxacin, enoxacin, norfloxacin and ofloxacin) from the group of quinolones and coumarins (coumermycin A1, clorobiocin and novobiocin) — all inhibitors of prokaryotic DNA topoisomerase II — were very potent eliminators of chloroplasts fromE. gracilis. In contrast, antitumor drugs (adriamycin, etoposide, teniposide and mitoxantrone) — antagonists of the eukaryotic counterpart — did not affect these semiautonomous photosynthetic organelles. These findings point out again the close evolutionary relationships between eubacteria and chloroplasts and are in agreement with the hypothesis of an endosymbiotic origin of chloroplasts.

  4. Angiotensin II regulates collagen metabolism through modulating tissue inhibitor of metalloproteinase-1 in diabetic skin tissues.

    PubMed

    Ren, Meng; Hao, Shaoyun; Yang, Chuan; Zhu, Ping; Chen, Lihong; Lin, Diaozhu; Li, Na; Yan, Li

    2013-09-01

    We investigated the effect of angiotensin II (Ang II) on matrix metalloproteinase-1 (MMP-1)/tissue inhibitor of metalloproteinase-1 (TIMP-1) balance in regulating collagen metabolism of diabetic skin. Skin tissues from diabetic model were collected, and the primary cultured fibroblasts were treated with Ang II receptor inhibitors before Ang II treatment. The collagen type I (Coll I) and collagen type III (Coll III) were measured by histochemistry. The expressions of transforming growth factor-β (TGF-β), MMP-1, TIMP-1 and propeptides of types I and III procollagens in skin tissues and fibroblasts were quantified using polymerase chain reaction (PCR), Western blot or enzyme-linked immunosorbent assay (ELISA). Collagen dysfunction was documented by changed collagen I/III ratio in streptozotocin (STZ)-injected mice compared with controls. This was accompanied by increased expression of TGF-β, TIMP-1 and propeptides of types I and III procollagens in diabetic skin tissues. In primary cultured fibroblasts, Ang II prompted collagen synthesis accompanied by increases in the expressions of TGF-β, TIMP-1 and types I and III procollagens, and these increases were inhibited by losartan, an Ang II type 1 (AT1) receptor blocker, but not affected by PD123319, an Ang II type 2 (AT2) receptor antagonist. These findings present evidence that Ang-II-mediated changes in the productions of MMP-1 and TIMP-1 occur via AT1 receptors and a TGF-β-dependent mechanism.

  5. Photosystem II inhibitor resistance in the Columbia Basin of Washington state

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato and mint (peppermint and spearmint) are commonly produced in the irrigated regions of the Pacific Northwest and both crops rely heavily on photosystem II (PSII) inhibitor herbicides metribuzin (potato) and terbacil (mint) for weed management. Seed was collected in 2010 from Powell amaranth, r...

  6. Analyzing the binding of Co(II)-specific inhibitors to the methionyl aminopeptidases from Escherichia coli and Pyrococcus furiosus.

    PubMed

    Mitra, Sanghamitra; Sheppard, George; Wang, Jieyi; Bennett, Brian; Holz, Richard C

    2009-05-01

    Methionine aminopeptidases (MetAPs) represent a unique class of protease that is capable of the hydrolytic removal of an N-terminal methionine residue from nascent polypeptide chains. MetAPs are physiologically important enzymes; hence, there is considerable interest in developing inhibitors that can be used as antiangiogenic and antimicrobial agents. A detailed kinetic and spectroscopic study has been performed to probe the binding of a triazole-based inhibitor and a bestatin-based inhibitor to both Mn(II)- and Co(II)-loaded type-I (Escherichia coli) and type-II (Pyrococcus furiosus) MetAPs. Both inhibitors were found to be moderate competitive inhibitors. The triazole-type inhibitor was found to interact with both active-site metal ions, while the bestatin-type inhibitor was capable of switching its mode of binding depending on the metal in the active site and the type of MetAP enzyme.

  7. Structural characterization of P1'-diversified urea-based inhibitors of glutamate carboxypeptidase II.

    PubMed

    Pavlicek, Jiri; Ptacek, Jakub; Cerny, Jiri; Byun, Youngjoo; Skultetyova, Lubica; Pomper, Martin G; Lubkowski, Jacek; Barinka, Cyril

    2014-05-15

    Urea-based inhibitors of human glutamate carboxypeptidase II (GCPII) have advanced into clinical trials for imaging metastatic prostate cancer. In parallel efforts, agents with increased lipophilicity have been designed and evaluated for targeting GCPII residing within the neuraxis. Here we report the structural and computational characterization of six complexes between GCPII and P1'-diversified urea-based inhibitors that have the C-terminal glutamate replaced by more hydrophobic moieties. The X-ray structures are complemented by quantum mechanics calculations that provide a quantitative insight into the GCPII/inhibitor interactions. These data can be used for the rational design of novel glutamate-free GCPII inhibitors with tailored physicochemical properties.

  8. [Apoptosis of human leukemic cells induced by topoisomerase I and II inhibitors].

    PubMed

    Solary, E; Dubrez, L; Eymin, B; Bertrand, R; Pommier, Y

    1996-03-01

    Comparison between five human leukemic lines (BV173, HL60, U937, K562, KCL22) suggest that the main determinant of their sensitivity to topoisomerase I (camptothecin) and II (VP-16) inhibitors is their ability to regulate cell cycle progression in response to specific DNA damage, then to die through apoptosis: the more the cells inhibit cell cycle progression, the less sensitive they are. The final pathway of apoptosis induction involves a cytoplasmic signal, active at neutral pH, needing magnesium, sensitive to various protease inhibitors and activated directly by staurosporine. Modulators of intracellular signaling (calcium chelators, calmodulin inhibitors, PKC modulators, kinase and phosphatase inhibitors) have no significant influence upon apoptosis induction. Conversely, apoptosis induction pathway is modified during monocytic differentiation of HL60 cells induced by phorbol esters. Lastly, poly(ADP-ribosyl)ation and chromatine structure should regulate apoptotic DNA fragmentation that is prevented by 3-aminobenzamide and spermine, respectively.

  9. Virtual and experimental high-throughput screening (HTS) in search of novel inosine 5'-monophosphate dehydrogenase II (IMPDH II) inhibitors

    NASA Astrophysics Data System (ADS)

    Dunkern, Torsten; Prabhu, Arati; Kharkar, Prashant S.; Goebel, Heike; Rolser, Edith; Burckhard-Boer, Waltraud; Arumugam, Premkumar; Makhija, Mahindra T.

    2012-11-01

    IMPDH (Inosine 5'-monophosphate dehydrogenase) catalyzes a rate-limiting step in the de novo biosynthesis of guanine nucleotides. IMPDH inhibition in sensitive cell types (e.g., lymphocytes) blocks proliferation (by blocking RNA and DNA synthesis as a result of decreased cellular levels of guanine nucleotides). This makes it an interesting target for cancer and autoimmune disorders. Currently available IMPDH inhibitors such as mycophenolic acid (MPA, uncompetitive inhibitor) and nucleoside analogs (e.g., ribavirin, competitive inhibitor after intracellular activation by phosphorylation) have unfavorable tolerability profiles which limit their use. Hence, the quest for novel IMPDH inhibitors continues. In the present study, a ligand-based virtual screening using IMPDH inhibitor pharmacophore models was performed on in-house compound collection. A total of 50,000 virtual hits were selected for primary screen using in vitro IMPDH II inhibition up to 10 μM. The list of 2,500 hits (with >70 % inhibition) was further subjected to hit confirmation for the determination of IC50 values. The hits obtained were further clustered using maximum common substructure based formalism resulting in 90 classes and 7 singletons. A thorough inspection of these yielded 7 interesting classes in terms of mini-SAR with IC50 values ranging from 0.163 μM to little over 25 μM. The average ligand efficiency was found to be 0.3 for the best class. The classes thus discovered represent structurally novel chemotypes which can be taken up for further development.

  10. Differential effects of viroporin inhibitors against feline infectious peritonitis virus serotypes I and II.

    PubMed

    Takano, Tomomi; Nakano, Kenta; Doki, Tomoyoshi; Hohdatsu, Tsutomu

    2015-05-01

    Feline infectious peritonitis virus (FIP virus: FIPV), a feline coronavirus of the family Coronaviridae, causes a fatal disease called FIP in wild and domestic cat species. The genome of coronaviruses encodes a hydrophobic transmembrane protein, the envelope (E) protein. The E protein possesses ion channel activity. Viral proteins with ion channel activity are collectively termed "viroporins". Hexamethylene amiloride (HMA), a viroporin inhibitor, can inhibit the ion channel activity of the E protein and replication of several coronaviruses. However, it is not clear whether HMA and other viroporin inhibitors affect replication of FIPV. We examined the effect of HMA and other viroporin inhibitors (DIDS [4,4'-disothiocyano-2,2'-stilbenedisulphonic acid] and amantadine) on infection by FIPV serotypes I and II. HMA treatment drastically decreased the titers of FIPV serotype I strains Black and KU-2 in a dose-dependent manner, but it only slightly decreased the titer of FIPV serotype II strain 79-1146. In contrast, DIDS treatment decreased the titer of FIPV serotype II strain 79-1146 in dose-dependent manner, but it only slightly decreased the titers of FIPV serotype I strains Black and KU-2. We investigated whether there is a difference in ion channel activity of the E protein between viral serotypes using E. coli cells expressing the E protein of FIPV serotypes I and II. No difference was observed, suggesting that a viroporin other than the E protein influences the differences in the actions of HMA and DIDS on FIPV serotypes I and II.

  11. Carbonic Anhydrase Interaction With Lipothioars Enites: A Novel Class of Isozymes I and II Inhibitors

    PubMed Central

    Timotheatou, Despina; Ioannou, Panayiotis V.; Scozzafava, Andrea; Briganti, Fabrizio

    1996-01-01

    The interaction of carbonic anhydrase (CA) isozymes I and II with a series of As(III) derivatives, dialkyl and diaryl rac-2,3-dimyristoyloxypropyldithioarsonites, was investigated kinetically and spectrophotometrically, utilizing the native and Co(II)-substituted enzymes. Depending on the substitution pattern at the -As(SR)2 moiety of the investigated derivatives, inactive compounds were found for R = phenyl or naphthyl, and active ones for derivatives containing carboxyl groups (R = CH2COOH, cysteinyl and glutathionyl). Together with the arsonolipids previously investigated, the active compounds of this series - the "lipothioarsenites"- constitute a novel class of CA inhibitors that bind to the metal ion within the enzyme active site, as proved by changes in the electronic spectra of adducts of such inhibitors with Co(II)CA. PMID:18475756

  12. Identification of type II and III DDR2 inhibitors.

    PubMed

    Richters, André; Nguyen, Hoang D; Phan, Trang; Simard, Jeffrey R; Grütter, Christian; Engel, Julian; Rauh, Daniel

    2014-05-22

    Discoidin domain-containing receptors (DDRs) exhibit a unique mechanism of action among the receptor tyrosine kinases (RTKs) because their catalytic activity is induced by extracellular collagen binding. Moreover, they are essential components in the assimilation of extracellular signals. Recently, DDRs were reported to be significantly linked to tumor progression in breast cancer by facilitating the processes of invasion, migration, and metastasis. Here, we report the successful development of a fluorescence-based, direct binding assay for the detection of type II and III DFG-out binders for DDR2. Using sequence alignments and homology modeling, we designed a DDR2 construct appropriate for fluorescent labeling. Successful assay development was validated by sensitive detection of a reference DFG-out binder. Subsequent downscaling led to convenient application to high-throughput screening formats. Screening of a representative compound library identified high-affinity DDR2 ligands validated by orthogonal activity-based assays, and a subset of identified compounds was further investigated with respect to DDR1 inhibition.

  13. Inflammatory Signaling by NOD-RIPK2 Is Inhibited by Clinically Relevant Type II Kinase Inhibitors

    PubMed Central

    Canning, Peter; Ruan, Qui; Schwerd, Tobias; Hrdinka, Matous; Maki, Jenny L.; Saleh, Danish; Suebsuwong, Chalada; Ray, Soumya; Brennan, Paul E.; Cuny, Gregory D.; Uhlig, Holm H.; Gyrd-Hansen, Mads; Degterev, Alexei; Bullock, Alex N.

    2015-01-01

    Summary RIPK2 mediates pro-inflammatory signaling from the bacterial sensors NOD1 and NOD2, and is an emerging therapeutic target in autoimmune and inflammatory diseases. We observed that cellular RIPK2 can be potently inhibited by type II inhibitors that displace the kinase activation segment, whereas ATP-competitive type I inhibition was only poorly effective. The most potent RIPK2 inhibitors were the US Food and Drug Administration-approved drugs ponatinib and regorafenib. Their mechanism of action was independent of NOD2 interaction and involved loss of downstream kinase activation as evidenced by lack of RIPK2 autophosphorylation. Notably, these molecules also blocked RIPK2 ubiquitination and, consequently, inflammatory nuclear factor κB signaling. In monocytes, the inhibitors selectively blocked NOD-dependent tumor necrosis factor production without affecting lipopolysaccharide-dependent pathways. We also determined the first crystal structure of RIPK2 bound to ponatinib, and identified an allosteric site for inhibitor development. These results highlight the potential for type II inhibitors to treat indications of RIPK2 activation as well as inflammation-associated cancers. PMID:26320862

  14. Inflammatory Signaling by NOD-RIPK2 Is Inhibited by Clinically Relevant Type II Kinase Inhibitors.

    PubMed

    Canning, Peter; Ruan, Qui; Schwerd, Tobias; Hrdinka, Matous; Maki, Jenny L; Saleh, Danish; Suebsuwong, Chalada; Ray, Soumya; Brennan, Paul E; Cuny, Gregory D; Uhlig, Holm H; Gyrd-Hansen, Mads; Degterev, Alexei; Bullock, Alex N

    2015-09-17

    RIPK2 mediates pro-inflammatory signaling from the bacterial sensors NOD1 and NOD2, and is an emerging therapeutic target in autoimmune and inflammatory diseases. We observed that cellular RIPK2 can be potently inhibited by type II inhibitors that displace the kinase activation segment, whereas ATP-competitive type I inhibition was only poorly effective. The most potent RIPK2 inhibitors were the US Food and Drug Administration-approved drugs ponatinib and regorafenib. Their mechanism of action was independent of NOD2 interaction and involved loss of downstream kinase activation as evidenced by lack of RIPK2 autophosphorylation. Notably, these molecules also blocked RIPK2 ubiquitination and, consequently, inflammatory nuclear factor κB signaling. In monocytes, the inhibitors selectively blocked NOD-dependent tumor necrosis factor production without affecting lipopolysaccharide-dependent pathways. We also determined the first crystal structure of RIPK2 bound to ponatinib, and identified an allosteric site for inhibitor development. These results highlight the potential for type II inhibitors to treat indications of RIPK2 activation as well as inflammation-associated cancers.

  15. Topoisomerase I and II inhibitors: chemical structure, mechanisms of action and role in cancer chemotherapy

    NASA Astrophysics Data System (ADS)

    Dezhenkova, L. G.; Tsvetkov, V. B.; Shtil, A. A.

    2014-01-01

    The review summarizes and analyzes recent published data on topoisomerase I and II inhibitors as potential antitumour agents. Functions and the mechanism of action of topoisomerases are considered. The molecular mechanism of interactions between low-molecular-weight compounds and these proteins is discussed. Topoisomerase inhibitors belonging to different classes of chemical compounds are systematically covered. Assays for the inhibition of topoisomerases and the possibilities of using the computer-aided modelling for the rational design of novel drugs for cancer chemotherapy are presented. The bibliography includes 127 references.

  16. Towards Development of Small Molecule Lipid II Inhibitors as Novel Antibiotics

    PubMed Central

    Chauhan, Jamal; Cardinale, Steven; Fang, Lei; Huang, Jing; Kwasny, Steven M.; Pennington, M. Ross; Basi, Kelly; diTargiani, Robert; Capacio, Benedict R.; MacKerell, Alexander D.; Opperman, Timothy J.; Fletcher, Steven; de Leeuw, Erik P. H.

    2016-01-01

    Recently we described a novel di-benzene-pyrylium-indolene (BAS00127538) inhibitor of Lipid II. BAS00127538 (1-Methyl-2,4-diphenyl-6-((1E,3E)-3-(1,3,3-trimethylindolin-2-ylidene)prop-1-en-1-yl)pyryl-1-ium) tetrafluoroborate is the first small molecule Lipid II inhibitor and is structurally distinct from natural agents that bind Lipid II, such as vancomycin. Here, we describe the synthesis and biological evaluation of 50 new analogs of BAS00127538 designed to explore the structure-activity relationships of the scaffold. The results of this study indicate an activity map of the scaffold, identifying regions that are critical to cytotoxicity, Lipid II binding and range of anti-bacterial action. One compound, 6jc48-1, showed significantly enhanced drug-like properties compared to BAS00127538. 6jc48-1 has reduced cytotoxicity, while retaining specific Lipid II binding and activity against Enterococcus spp. in vitro and in vivo. Further, this compound showed a markedly improved pharmacokinetic profile with a half-life of over 13 hours upon intravenous and oral administration and was stable in plasma. These results suggest that scaffolds like that of 6jc48-1 can be developed into small molecule antibiotic drugs that target Lipid II. PMID:27776124

  17. Identification of Noncompetitive Inhibitors of Cytosolic 5'-Nucleotidase II Using a Fragment-Based Approach.

    PubMed

    Marton, Zsuzsanna; Guillon, Rémi; Krimm, Isabelle; Preeti; Rahimova, Rahila; Egron, David; Jordheim, Lars P; Aghajari, Nushin; Dumontet, Charles; Périgaud, Christian; Lionne, Corinne; Peyrottes, Suzanne; Chaloin, Laurent

    2015-12-24

    We used a combined approach based on fragment-based drug design (FBDD) and in silico methods to design potential inhibitors of the cytosolic 5'-nucleotidase II (cN-II), which has been recognized as an important therapeutic target in hematological cancers. Two subgroups of small compounds (including adenine and biaryl moieties) were identified as cN-II binders and a fragment growing strategy guided by molecular docking was considered. Five compounds induced a strong inhibition of the 5'-nucleotidase activity in vitro, and the most potent ones were characterized as noncompetitive inhibitors. Biological evaluation in cancer cell lines showed synergic effect with selected anticancer drugs. Structural studies using X-ray crystallography lead to the identification of new binding sites for two derivatives and of a new crystal form showing important domain swapping. Altogether, the strategy developed herein allowed identifying new original noncompetitive inhibitors against cN-II that act in a synergistic manner with well-known antitumoral agents.

  18. Insight into selectivity of peptidomimetic inhibitors with modified statine core for plasmepsin II of Plasmodium falciparum over human cathepsin D.

    PubMed

    Dali, Brice; Keita, Melalie; Megnassan, Eugene; Frecer, Vladimir; Miertus, Stanislav

    2012-04-01

    Plasmepsin II (PlmII), an aspartic protease expressed in the food vacuole of Plasmodium falciparum (pf), cleaves the hemoglobin of the host during the erythrocytic stage of the parasite life cycle. Various peptidomimetic inhibitors of PlmII reported so far discriminate poorly between the drug target and aspartic proteases of the host organism, e.g., human cathepsinD (hCatD). hCatD is a protein digestion enzyme and signaling molecule involved in a variety of physiological processes; therefore, inhibition of hCatD by PlmII inhibitors may lead to pathophysiological conditions. In this study, binding of PlmII inhibitors has been modeled using the crystal structures of pfPlmII and hCatD complexes to gain insight into structural requirements underlying the target selectivity. A series of 26 inhibitors were modeled in the binding clefts of the pfPlmII and hCatD to establish QSAR models of the protease inhibition. In addition, 3D-QSAR pharmacophore models were generated for each enzyme. It was concluded that the contributions of the P(2) and P(3') residues to the inhibitor's binding affinity are responsible for the target selectivity. Based on these findings, new inhibitor candidates were designed with predicted inhibition constants K (pre)(i PlmII) reaching 0.2nm and selectivity index (S.I.)=K(pre)(i PlmII) >1200.

  19. Inactivation of alpha 1-proteinase inhibitor by Cu(II) and hydrogen peroxide.

    PubMed

    Kwon, N S; Chan, P C; Kesner, L

    1990-03-01

    When alpha 1-proteinase inhibitor was treated with 1-5 microM CuSO4 in the presence of H2O2 (250-1000 microM), its elastase inhibitory capacity was markedly decreased. Several other metal ions tested had either very little or no effect. The Cu(II)-catalyzed decreased in the inhibition of elastase activity can also be demonstrated in dialyzed plasma. These results are consistent with the hypothesis that in several pathological conditions in which extracellular copper levels are elevated, Cu(II)-catalyzed peroxidation of alpha 1-proteinase inhibitor may occur at sites of inflammation where H2O2 is secreted as a major product by activated phagocytes.

  20. Urotensin II inhibitor eases neuropathic pain by suppressing the JNK/NF-κB pathway.

    PubMed

    Li, Jing; Zhao, Pan-Pan; Hao, Ting; Wang, Dan; Wang, Yu; Zhu, Yang-Zi; Wu, Yu-Qing; Zhou, Cheng-Hua

    2017-02-01

    Urotensin II (U-II), a cyclic peptide originally isolated from the caudal neurosecretory system of fishes, can produce proinflammatory effects through its specific G protein-coupled receptor, GPR14. Neuropathic pain, a devastating disease, is related to excessive inflammation in the spinal dorsal horn. However, the relationship between U-II and neuropathic pain has not been reported. This study was designed to investigate the effect of U-II antagonist on neuropathic pain and to understand the associated mechanisms. We reported that U-II and its receptor GPR14 were persistently upregulated and activated in the dorsal horn of L4-6 spinal cord segments after chronic constriction injury (CCI) in rats. Intrathecal injection of SB657510, a specific antagonist against U-II, reversed CCI-induced thermal hyperalgesia and mechanical allodynia. Furthermore, we found that SB657510 reduced the expression of phosphorylated c-Jun N-terminal kinase (p-JNK) and nuclear factor-κB (NF-κB) p65 as well as subsequent secretion of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α). It was also showed that both the JNK inhibitor SP600125 and the NF-κB inhibitor PDTC significantly attenuated thermal hyperalgesia and mechanical allodynia in CCI rats. Our present research showed that U-II receptor antagonist alleviated neuropathic pain possibly through the suppression of the JNK/NF-κB pathway in CCI rats, which will contribute to the better understanding of function of U-II and pathogenesis of neuropathic pain.

  1. "Addition" and "Subtraction": Selectivity Design for Type II Maternal Embryonic Leucine Zipper Kinase Inhibitors.

    PubMed

    Chen, Xin; Giraldes, John; Sprague, Elizabeth R; Shakya, Subarna; Chen, Zhuoliang; Wang, Yaping; Joud, Carol; Mathieu, Simon; Chen, Christine Hiu-Tung; Straub, Christopher; Duca, Jose; Hurov, Kristen; Yuan, Yanqiu; Shao, Wenlin; Touré, B Barry

    2017-03-09

    While adding the structural features that are more favored by on-target activity is the more common strategy in selectivity optimization, the opposite strategy of subtracting the structural features that contribute more to off-target activity can also be very effective. Reported here is our successful effort of improving the kinase selectivity of type II maternal embryonic leucine zipper kinase inhibitors by applying these two complementary approaches together, which clearly demonstrates the powerful synergy between them.

  2. Selective CNS Uptake of the GCP-II Inhibitor 2-PMPA following Intranasal Administration

    PubMed Central

    Rais, Rana; Wozniak, Krystyna; Wu, Ying; Niwa, Minae; Stathis, Marigo; Alt, Jesse; Giroux, Marc; Sawa, Akira; Rojas, Camilo; Slusher, Barbara S.

    2015-01-01

    Glutamate carboxypeptidase II (GCP-II) is a brain metallopeptidase that hydrolyzes the abundant neuropeptide N-acetyl-aspartyl-glutamate (NAAG) to NAA and glutamate. Small molecule GCP-II inhibitors increase brain NAAG, which activates mGluR3, decreases glutamate, and provide therapeutic utility in a variety of preclinical models of neurodegenerative diseases wherein excess glutamate is presumed pathogenic. Unfortunately no GCP-II inhibitor has advanced clinically, largely due to their highly polar nature resulting in insufficient oral bioavailability and limited brain penetration. Herein we report a non-invasive route for delivery of GCP-II inhibitors to the brain via intranasal (i.n.) administration. Three structurally distinct classes of GCP-II inhibitors were evaluated including DCMC (urea-based), 2-MPPA (thiol-based) and 2-PMPA (phosphonate-based). While all showed some brain penetration following i.n. administration, 2-PMPA exhibited the highest levels and was chosen for further evaluation. Compared to intraperitoneal (i.p.) administration, equivalent doses of i.n. administered 2-PMPA resulted in similar plasma exposures (AUC0-t, i.n./AUC0-t, i.p. = 1.0) but dramatically enhanced brain exposures in the olfactory bulb (AUC0-t, i.n./AUC0-t, i.p. = 67), cortex (AUC0-t, i.n./AUC0-t, i.p. = 46) and cerebellum (AUC0-t, i.n./AUC0-t, i.p. = 6.3). Following i.n. administration, the brain tissue to plasma ratio based on AUC0-t in the olfactory bulb, cortex, and cerebellum were 1.49, 0.71 and 0.10, respectively, compared to an i.p. brain tissue to plasma ratio of less than 0.02 in all areas. Furthermore, i.n. administration of 2-PMPA resulted in complete inhibition of brain GCP-II enzymatic activity ex-vivo confirming target engagement. Lastly, because the rodent nasal system is not similar to humans, we evaluated i.n. 2-PMPA also in a non-human primate. We report that i.n. 2-PMPA provides selective brain delivery with micromolar concentrations. These studies support

  3. SphK1 inhibitor II (SKI-II) inhibits acute myelogenous leukemia cell growth in vitro and in vivo

    SciTech Connect

    Yang, Li; Weng, Wei; Sun, Zhi-Xin; Fu, Xian-Jie; Ma, Jun Zhuang, Wen-Fang

    2015-05-15

    Previous studies have identified sphingosine kinase 1 (SphK1) as a potential drug target for treatment of acute myeloid leukemia (AML). In the current study, we investigated the potential anti-leukemic activity of a novel and specific SphK1 inhibitor, SKI-II. We demonstrated that SKI-II inhibited growth and survival of human AML cell lines (HL-60 and U937 cells). SKI-II was more efficient than two known SphK1 inhibitors SK1-I and FTY720 in inhibiting AML cells. Meanwhile, it induced dramatic apoptosis in above AML cells, and the cytotoxicity by SKI-II was almost reversed by the general caspase inhibitor z-VAD-fmk. SKI-II treatment inhibited SphK1 activation, and concomitantly increased level of sphingosine-1-phosphate (S1P) precursor ceramide in AML cells. Conversely, exogenously-added S1P protected against SKI-II-induced cytotoxicity, while cell permeable short-chain ceramide (C6) aggravated SKI-II's lethality against AML cells. Notably, SKI-II induced potent apoptotic death in primary human AML cells, but was generally safe to the human peripheral blood mononuclear cells (PBMCs) isolated from healthy donors. In vivo, SKI-II administration suppressed growth of U937 leukemic xenograft tumors in severe combined immunodeficient (SCID) mice. These results suggest that SKI-II might be further investigated as a promising anti-AML agent. - Highlights: • SKI-II inhibits proliferation and survival of primary and transformed AML cells. • SKI-II induces apoptotic death of AML cells, but is safe to normal PBMCs. • SKI-II is more efficient than two known SphK1 inhibitors in inhibiting AML cells. • SKI-II inhibits SphK1 activity, while increasing ceramide production in AML cells. • SKI-II dose-dependently inhibits U937 xenograft growth in SCID mice.

  4. Substrate and Inhibitor Specificity of the Type II p21-Activated Kinase, PAK6

    PubMed Central

    Gao, Jia; Ha, Byung Hak; Lou, Hua Jane; Morse, Elizabeth M.; Zhang, Rong; Calderwood, David A.; Turk, Benjamin E.; Boggon, Titus J.

    2013-01-01

    The p21-activated kinases (PAKs) are important effectors of Rho-family small GTPases. The PAK family consists of two groups, type I and type II, which have different modes of regulation and signaling. PAK6, a type II PAK, influences behavior and locomotor function in mice and has an ascribed role in androgen receptor signaling. Here we show that PAK6 has a peptide substrate specificity very similar to the other type II PAKs, PAK4 and PAK5 (PAK7). We find that PAK6 catalytic activity is inhibited by a peptide corresponding to its N-terminal pseudosubstrate. Introduction of a melanoma-associated mutation, P52L, into this peptide reduces pseudosubstrate autoinhibition of PAK6, and increases phosphorylation of its substrate PACSIN1 (Syndapin I) in cells. Finally we determine two co-crystal structures of PAK6 catalytic domain in complex with ATP-competitive inhibitors. We determined the 1.4 Å co-crystal structure of PAK6 with the type II PAK inhibitor PF-3758309, and the 1.95 Å co-crystal structure of PAK6 with sunitinib. These findings provide new insights into the structure-function relationships of PAK6 and may facilitate development of PAK6 targeted therapies. PMID:24204982

  5. Switch control pocket inhibitors of p38-MAP kinase. Durable type II inhibitors that do not require binding into the canonical ATP hinge region

    SciTech Connect

    Ahn, Yu Mi; Clare, Michael; Ensinger, Carol L.; Hood, Molly M.; Lord, John W.; Lu, Wei-Ping; Miller, David F.; Patt, William C.; Smith, Bryan D.; Vogeti, Lakshminarayana; Kaufman, Michael D.; Petillo, Peter A.; Wise, Scott C.; Abendroth, Jan; Chun, Lawrence; Clark, Robin; Feese, Michael; Kim, Hidong; Stewart, Lance; Flynn, Daniel L.

    2012-01-20

    Switch control pocket inhibitors of p38-alpha kinase are described. Durable type II inhibitors were designed which bind to arginines (Arg67 or Arg70) that function as key residues for mediating phospho-threonine 180 dependant conformational fluxing of p38-alpha from an inactive type II state to an active type I state. Binding to Arg70 in particular led to potent inhibitors, exemplified by DP-802, which also exhibited high kinase selectivity. Binding to Arg70 obviated the requirement for binding into the ATP Hinge region. X-ray crystallography revealed that DP-802 and analogs induce an enhanced type II conformation upon binding to either the unphosphorylated or the doubly phosphorylated form of p38-alpha kinase.

  6. Photosystem II-inhibitors play a limited role in sweet corn response to 4-hydroxyphenyl pyruvate dioxygenase-inhibiting herbicides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Postemergence (POST) application of 4-hydroxyphenyl pyruvate dioxygenase (HPPD) inhibitors in combination with a photosystem II (PSII) inhibitor, such as atrazine, is common practice in sweet corn production. Given the sensitivity of sweet corn to HPPD-inhibiting herbicides, the objective of this wo...

  7. Development and bioassay of transgenic Chinese cabbage expressing potato proteinase inhibitor II gene

    PubMed Central

    Zhang, Junjie; Liu, Fan; Yao, Lei; Luo, Chen; Yin, Yue; Wang, Guixiang; Huang, Yubi

    2012-01-01

    Lepidopteran larvae are the most injurious pests of Chinese cabbage production. We attempted the development of transgenic Chinese cabbage expressing the potato proteinase inhibitor II gene (pinII) and bioassayed the pest-repelling ability of these transgenic plants. Cotyledons with petioles from aseptic seedlings were used as explants for Agrobacterium-mediated in vitro transformation. Agrobacterium tumefaciens C58 contained the binary vector pBBBasta-pinII-bar comprising pinII and bar genes. Plants showing vigorous PPT resistance were obtained by a series concentration selection for PPT resistance and subsequent regeneration of leaf explants dissected from the putative chimera. Transgenic plants were confirmed by PCR and genomic Southern blotting, which showed that the bar and pinII genes were integrated into the plant genome. Double haploid homozygous transgenic plants were obtained by microspore culture. The pinII expression was detected using quantitative real time polymerase chain reaction (qRT-PCR) and detection of PINII protein content in the transgenic homozygous lines. Insect-feeding trials using the larvae of cabbage worm (Pieris rapae) and the larvae of the diamondback moth (Plutella xylostella) showed higher larval mortality, stunted larval development, and lower pupal weights, pupation rates, and eclosion rates in most of the transgenic lines in comparison with the corresponding values in the non-transformed wild-type line. PMID:23136521

  8. Selective Loss of Cysteine Residues and Disulphide Bonds in a Potato Proteinase Inhibitor II Family

    PubMed Central

    Li, Xiu-Qing; Zhang, Tieling; Donnelly, Danielle

    2011-01-01

    Disulphide bonds between cysteine residues in proteins play a key role in protein folding, stability, and function. Loss of a disulphide bond is often associated with functional differentiation of the protein. The evolution of disulphide bonds is still actively debated; analysis of naturally occurring variants can promote understanding of the protein evolutionary process. One of the disulphide bond-containing protein families is the potato proteinase inhibitor II (PI-II, or Pin2, for short) superfamily, which is found in most solanaceous plants and participates in plant development, stress response, and defence. Each PI-II domain contains eight cysteine residues (8C), and two similar PI-II domains form a functional protein that has eight disulphide bonds and two non-identical reaction centres. It is still unclear which patterns and processes affect cysteine residue loss in PI-II. Through cDNA sequencing and data mining, we found six natural variants missing cysteine residues involved in one or two disulphide bonds at the first reaction centre. We named these variants Pi7C and Pi6C for the proteins missing one or two pairs of cysteine residues, respectively. This PI-II-7C/6C family was found exclusively in potato. The missing cysteine residues were in bonding pairs but distant from one another at the nucleotide/protein sequence level. The non-synonymous/synonymous substitution (Ka/Ks) ratio analysis suggested a positive evolutionary gene selection for Pi6C and various Pi7C. The selective deletion of the first reaction centre cysteine residues that are structure-level-paired but sequence-level-distant in PI-II illustrates the flexibility of PI-II domains and suggests the functionality of their transient gene versions during evolution. PMID:21494600

  9. Structure-activity exploration of a small-molecule Lipid II inhibitor.

    PubMed

    Fletcher, Steven; Yu, Wenbo; Huang, Jing; Kwasny, Steven M; Chauhan, Jay; Opperman, Timothy J; MacKerell, Alexander D; de Leeuw, Erik P H

    2015-01-01

    We have recently identified low-molecular weight compounds that act as inhibitors of Lipid II, an essential precursor of bacterial cell wall biosynthesis. Lipid II comprises specialized lipid (bactoprenol) linked to a hydrophilic head group consisting of a peptidoglycan subunit (N-acetyl glucosamine [GlcNAc]-N-acetyl muramic acid [MurNAc] disaccharide coupled to a short pentapeptide moiety) via a pyrophosphate. One of our lead compounds, a diphenyl-trimethyl indolene pyrylium, termed BAS00127538, interacts with the MurNAc moiety and the isoprenyl tail of Lipid II. Here, we report on the structure-activity relationship of BAS00127538 derivatives obtained by in silico analyses and de novo chemical synthesis. Our results indicate that Lipid II binding and bacterial killing are related to three features: the diphenyl moiety, the indolene moiety, and the positive charge of the pyrylium. Replacement of the pyrylium moiety with an N-methyl pyridinium, which may have importance in stability of the molecule, did not alter Lipid II binding or antibacterial potency.

  10. Oxidative inactivation of alpha 1-proteinase inhibitor by alveolar epithelial type II cells.

    PubMed

    Wallaert, B; Aerts, C; Gressier, B; Gosset, P; Voisin, C

    1993-12-01

    The aim of this work was to evaluate the ability of guinea pig alveolar epithelial type II cells to generate significant amounts of reactive oxygen species to inactivate alpha 1-proteinase inhibitor (alpha 1-PI). Inactivation of alpha 1-PI was evaluated by its inhibitory activity against porcine pancreatic elastase and was expressed as a percentage. The same experiments were performed in parallel with alveolar macrophages (AM) obtained from the same animals and with MRC-5 fibroblasts. Both type II cells and AM released significant amounts of hydrogen peroxide and superoxide, whereas the fibroblasts did not. Unstimulated type II cells (0.5 +/- 2%), AM (1.2 +/- 1.5%), and fibroblasts (0.5 +/- 0.5%) were unable to inactivate alpha 1-PI. Addition of phorbol myristate acetate did not increase their ability to inactivate alpha 1-PI. In contrast, type II cells (79.7 +/- 7%) and AM (80.1 +/- 8%) dramatically inactivated alpha 1-PI in the presence of myeloperoxidase (25 mU/ml), whereas fibroblasts did not. Addition of catalase to the reaction significantly prevented the inactivation of alpha 1-PI. Western blot analysis of alpha 1-PI did not reveal a significant proteolysis of alpha 1-PI, which supports the hypothesis that, in the presence of neutrophil-derived myeloperoxidase, type II cells may oxidatively inactivate alpha 1-PI.

  11. Natural diterpenes from Croton ciliatoglanduliferus as photosystem II and photosystem I inhibitors in spinach chloroplasts.

    PubMed

    Morales-Flores, Félix; Aguilar, María Isabel; King-Díaz, Beatriz; de Santiago-Gómez, Jesús-Ricardo; Lotina-Hennsen, Blas

    2007-01-01

    In our search for new natural photosynthetic inhibitors that could lead to the development of "green herbicides" less toxic to environment, the diterpene labdane-8alpha,15-diol (1) and its acetyl derivative (2) were isolated for the first time from Croton ciliatoglanduliferus Ort. They inhibited photophosphorylation, electron transport (basal, phosphorylating and uncoupled) and the partial reactions of both photosystems in spinach thylakoids. Compound 1 inhibits the photosystem II (PS II) partial reaction from water to Na(+) Silicomolibdate (SiMo) and has no effect on partial reaction from diphenylcarbazide (DPC) to 2,6-dichlorophenol indophenol (DCPIP), therefore 1 inhibits at the water splitting enzyme and also inhibits PS I partial reaction from reduced phenylmetasulfate (PMS) to methylviologen (MV). Thus, it also inhibits in the span of P(700) to Iron sulfur center X (F(X)). Compound 2 inhibits both, the PS II partial reactions from water to SiMo and from DPC to DCPIP; besides this, it inhibits the photosystem I (PS I) partial reaction from reduced PMS to MV. With these results, we concluded that the targets of the natural product 2 are located at the water splitting enzyme, and at P(680) in PS II and at the span of P(700) to F(X) in PS I. The results of compounds 1 and 2 on PS II were corroborated by chlorophyll a fluorescence.

  12. Heterologous expression of Cenchritis muricatus protease inhibitor II (CmPI-II) in Pichia pastoris system: Purification, isotopic labeling and preliminary characterization.

    PubMed

    Cabrera-Muñoz, Aymara; Rojas, Laritza; Gil, Dayrom F; González-González, Yamile; Mansur, Manuel; Camejo, Ayamey; Pires, José R; Alonso-Del-Rivero Antigua, Maday

    2016-10-01

    Cenchritis muricatus protease inhibitor II (CmPI-II) is a tight-binding serine protease inhibitor of the Kazal family with an atypical broad specificity, being active against several proteases such as bovine pancreatic trypsin, human neutrophil elastase and subtilisin A. CmPI-II 3D structures are necessary for understanding the molecular basis of its activity. In the present work, we describe an efficient and straightforward recombinant expression strategy, as well as a cost-effective procedure for isotope labeling for NMR structure determination purposes. The vector pCM101 containing the CmPI-II gene, under the control of Pichia pastoris AOX1 promoter was constructed. Methylotrophic Pichia pastoris strain KM71H was then transformed with the plasmid and the recombinant protein (rCmPI-II) was expressed in benchtop fermenter in unlabeled or (15)N-labeled forms using ammonium chloride ((15)N, 99%) as the sole nitrogen source. Protein purification was accomplished by sequential cation exchange chromatography in STREAMLINE DirectHST, anion exchange chromatography on Hitrap Q-Sepharose FF and gel filtration on Superdex 75 10/30, yielding high quantities of pure rCmPI-II and (15)N rCmPI-II. Recombinant proteins displayed similar functional features as compared to the natural inhibitor and NMR spectra indicated folded and homogeneously labeled samples, suitable for further studies of structure and protease-inhibitor interactions.

  13. WRN protects against topo I but not topo II inhibitors by preventing DNA break formation

    PubMed Central

    Christmann, Markus; Tomicic, Maja T.; Gestrich, Christopher; Roos, Wynand P.; Bohr, Vilhelm A.; Kaina, Bernd

    2008-01-01

    The Werner syndrome helicase/3′-exonuclease (WRN) is a major component of the DNA repair and replication machinery. To analyze whether WRN is involved in the repair of topoisomerase-induced DNA damage we utilized U2-OS cells, in which WRN is stably down-regulated (wrn-kd), and the corresponding wild-type cells (wrn-wt). We show that cells not expressing WRN are hypersensitive to the toxic effect of the topoisomerase I inhibitor topotecan, but not to the topoisomerase II inhibitor etoposide. This was shown by mass survival assays, colony formation and induction of apoptosis. Upon topotecan treatment WRN deficient cells showed enhanced DNA replication inhibition and S-phase arrest, whereas after treatment with etoposide they showed the same cell cycle response as the wild-type. A considerable difference between WRN and wild-type cells was also observed for DNA single-and double-strand break formation in response to topotecan. Topotecan induced most DNA single-strand breaks 6 h after treatment. In both wrn-wt and wrn-kd cells these breaks were repaired at similar kinetics. However, in wrn-kd but not wrn-wt cells they were converted into DNA double-strand breaks (DSBs) at high frequency, as shown by neutral comet assay and phosphorylation of H2AX. Our data provide evidence that WRN is involved in the repair of topoisomerase I, but not topoisomerase II-induced DNA damage, most likely via preventing the conversion of DNA single-strand breaks into DSBs during the resolution of stalled replication forks at topo I–DNA complexes. We suggest that the WRN status of tumor cells impacts anticancer therapy with topoisomerase I, but not topoisomerase II inhibitors. PMID:18805512

  14. Rational Design Synthesis and Evaluation of New Selective Inhibitors of Microbial Class II (Zinc Dependent) Fructose Bis-phosphate Aldolases

    SciTech Connect

    R Daher; M Coincon; M Fonvielle; P Gest; M Guerin; M Jackson; J Sygusch; M Therisod

    2011-12-31

    We report the synthesis and biochemical evaluation of several selective inhibitors of class II (zinc dependent) fructose bis-phosphate aldolases (Fba). The products were designed as transition-state analogues of the catalyzed reaction, structurally related to the substrate fructose bis-phosphate (or sedoheptulose bis-phosphate) and based on an N-substituted hydroxamic acid, as a chelator of the zinc ion present in active site. The compounds synthesized were tested on class II Fbas from various pathogenic microorganisms and, by comparison, on a mammalian class I Fba. The best inhibitor shows Ki against class II Fbas from various pathogens in the nM range, with very high selectivity (up to 105). Structural analyses of inhibitors in complex with aldolases rationalize and corroborate the enzymatic kinetics results. These inhibitors represent lead compounds for the preparation of new synthetic antibiotics, notably for tuberculosis prophylaxis.

  15. Copper (II) and zinc (II) complexes with flavanone derivatives: Identification of potential cholinesterase inhibitors by on-flow assays.

    PubMed

    Sarria, André Lucio Franceschini; Vilela, Adriana Ferreira Lopes; Frugeri, Bárbara Mammana; Fernandes, João Batista; Carlos, Rose Maria; da Silva, Maria Fátima das Graças Fernandes; Cass, Quezia Bezerra; Cardoso, Carmen Lúcia

    2016-11-01

    Metal chelates strongly influence the nature and magnitude of pharmacological activities in flavonoids. In recent years, studies have shown that a promising class of flavanone-metal ion complexes can act as selective cholinesterase inhibitors (ChEIs), which has led our group to synthesize a new series of flavanone derivatives (hesperidin, hesperetin, naringin, and naringenin) complexed to either copper (II) or zinc (II) and to evaluate their potential use as selective ChEIs. Most of the synthesized complexes exhibited greater inhibitory activity against acetylcholinesterase (AChE) than against butyrylcholinesterase (BChE). Nine of these complexes constituted potent, reversible, and selective ChEIs with inhibitory potency (IC50) and inhibitory constant (Ki) ranging from 0.02 to 4.5μM. Copper complexes with flavanone-bipyridine derivatives afforded the best inhibitory activity against AChE and BChE. The complex Cu(naringin)(2,2'-bipyridine) (11) gave IC50 and Ki values of 0.012±0.002 and 0.07±0.01μM for huAChE, respectively, which were lower than the inhibitory values obtained for standard galanthamine (IC50=206±30.0 and Ki=126±18.0μM). Evaluation of the inhibitory activity of this complex against butyrylcholinesterase from human serum (huBChE) gave IC50 and Ki values of 8.0±1.4 and 2.0±0.1μM, respectively. A Liquid Chromatography-Immobilized Capillary Enzyme Reactor by UV detection (LC-ICER-UV) assay allowed us to determine the IC50 and Ki values and the type of mechanism for the best inhibitors.

  16. Current ideas on the biology of IGFBP-6: More than an IGF-II inhibitor?

    PubMed

    Bach, Leon A

    IGFBP-6 binds IGF-II with higher affinity than IGF-I and it is a relatively specific inhibitor of IGF-II actions. More recently, IGFBP-6 has also been reported to have IGF-independent effects on cell proliferation, survival, differentiation and migration. IGFBP-6 binds to several ligands in the extracellular space, cytoplasm and nucleus. These interactions, together with activation of distinct intracellular signaling pathways, may contribute to its IGF-independent actions; for example, IGF-independent migration induced by IGFBP-6 involves interaction with prohibitin-2 and activation of MAP kinase pathways. A major challenge for the future is delineating the relative roles of the IGF-dependent and -independent actions of IGFBP-6, which may lead to the development of therapeutic approaches for diseases including cancer.

  17. Effects of a lipoxygenase inhibitor, panaxynol, on vascular contraction induced by angiotensin II.

    PubMed

    Takai, S; Jin, D; Kirimura, K; Ikeda, J; Sakaguchi, M; Baba, K; Fujita, T; Miyazaki, M

    1999-05-01

    We investigated whether a lipoxygenase inhibitor, panaxynol, affected the vascular contraction induced by angiotensin (Ang) II and the mean arterial pressure in spontaneously hypertensive rats (SHR). Panaxynol suppressed dose-dependently the contractile responses induced by 30 nM Ang II in isolated intact and endothelial cell-denuded aorta in the hamster. IC50 values in the intact and endothelial cell-denuded aorta were 23 and 20 microM, respectively. In SHR, the mean arterial pressure after injection of 30 and 60 mg/kg panaxynol was reduced, and the maximum hypotensive values were 23 and 48 mmHg, respectively. Thus, lipoxygenase products may affect the renin-angiotensin system.

  18. The anticancer multi-kinase inhibitor dovitinib also targets topoisomerase I and topoisomerase II.

    PubMed

    Hasinoff, Brian B; Wu, Xing; Nitiss, John L; Kanagasabai, Ragu; Yalowich, Jack C

    2012-12-15

    Dovitinib (TKI258/CHIR258) is a multi-kinase inhibitor in phase III development for the treatment of several cancers. Dovitinib is a benzimidazole-quinolinone compound that structurally resembles the bisbenzimidazole minor groove binding dye Hoechst 33258. Dovitinib bound to DNA as shown by its ability to increase the DNA melting temperature and by increases in its fluorescence spectrum that occurred upon the addition of DNA. Molecular modeling studies of the docking of dovitinib into an X-ray structure of a Hoechst 33258-DNA complex showed that dovitinib could reasonably be accommodated in the DNA minor groove. Because DNA binders are often topoisomerase I (EC 5.99.1.2) and topoisomerase II (EC 5.99.1.3) inhibitors, the ability of dovitinib to inhibit these DNA processing enzymes was also investigated. Dovitinib inhibited the catalytic decatenation activity of topoisomerase IIα. It also inhibited the DNA-independent ATPase activity of yeast topoisomerase II which suggested that it interacted with the ATP binding site. Using isolated human topoisomerase IIα, dovitinib stabilized the enzyme-cleavage complex and acted as a topoisomerase IIα poison. Dovitinib was also found to be a cellular topoisomerase II poison in human leukemia K562 cells and induced double-strand DNA breaks in K562 cells as evidenced by increased phosphorylation of H2AX. Finally, dovitinib inhibited the topoisomerase I-catalyzed relaxation of plasmid DNA and acted as a cellular topoisomerase I poison. In conclusion, the cell growth inhibitory activity and the anticancer activity of dovitinib may result not only from its ability to inhibit multiple kinases, but also, in part, from its ability to target topoisomerase I and topoisomerase II.

  19. Discovery of Bacterial Fatty Acid Synthase Type II Inhibitors Using a Novel Cellular Bioluminescent Reporter Assay

    PubMed Central

    Wallace, Joselynn; Bowlin, Nicholas O.; Mills, Debra M.; Saenkham, Panatda; Kwasny, Steven M.; Opperman, Timothy J.; Williams, John D.; Rock, Charles O.; Bowlin, Terry L.

    2015-01-01

    Novel, cellular, gain-of-signal, bioluminescent reporter assays for fatty acid synthesis type II (FASII) inhibitors were constructed in an efflux-deficient strain of Pseudomonas aeruginosa and based on the discovery that FASII genes in P. aeruginosa are coordinately upregulated in response to pathway disruption. A screen of 115,000 compounds identified a series of sulfonamidobenzamide (SABA) analogs, which generated strong luminescent signals in two FASII reporter strains but not in four control reporter strains designed to respond to inhibitors of pathways other than FASII. The SABA analogs selectively inhibited lipid biosynthesis in P. aeruginosa and exhibited minimal cytotoxicity to mammalian cells (50% cytotoxic concentration [CC50] ≥ 80 μM). The most potent SABA analogs had MICs of 0.5 to 7.0 μM (0.2 to 3.0 μg/ml) against an efflux-deficient Escherichia coli (ΔtolC) strain but had no detectable MIC against efflux-proficient E. coli or against P. aeruginosa (efflux deficient or proficient). Genetic, molecular genetic, and biochemical studies revealed that SABA analogs target the enzyme (AccC) catalyzing the biotin carboxylase half-reaction of the acetyl coenzyme A (acetyl-CoA) carboxylase step in the initiation phase of FASII in E. coli and P. aeruginosa. These results validate the capability and the sensitivity of this novel bioluminescent reporter screen to identify inhibitors of E. coli and P. aeruginosa FASII. PMID:26169404

  20. Finding Potent Sirt Inhibitor in Coffee: Isolation, Confirmation and Synthesis of Javamide-II (N-Caffeoyltryptophan) as Sirt1/2 Inhibitor.

    PubMed

    Park, Jae B

    2016-01-01

    Recent studies suggest that Sirt inhibition may have beneficial effects on several human diseases such as neurodegenerative diseases and cancer. Coffee is one of most popular beverages with several positive health effects. Therefore, in this paper, potential Sirt inhibitors were screened using coffee extract. First, HPLC was utilized to fractionate coffee extract, then screened using a Sirt1/2 inhibition assay. The screening led to the isolation of a potent Sirt1/2 inhibitor, whose structure was determined as javamide-II (N-caffeoyltryptophan) by NMR. For confirmation, the amide was chemically synthesized and its capacity of inhibiting Sirt1/2 was also compared with the isolated amide. Javamide-II inhibited Sirt2 (IC50; 8.7 μM) better than Sirt1(IC50; 34μM). Since javamide-II is a stronger inhibitor for Sirt2 than Sirt1. The kinetic study was performed against Sirt2. The amide exhibited noncompetitive Sirt2 inhibition against the NAD+ (Ki = 9.8 μM) and showed competitive inhibition against the peptide substrate (Ki = 5.3 μM). Also, a docking simulation showed stronger binding pose of javamide-II to Sirt2 than AGK2. In cellular levels, javamide-II was able to increase the acetylation of total lysine, cortactin and histone H3 in neuronal NG108-15 cells. In the same cells, the amide also increased the acetylation of lysine (K382) in p53, but not (K305). This study suggests that Javamide-II found in coffee may be a potent Sirt1/2 inhibitor, probably with potential use in some conditions of human diseases.

  1. Finding Potent Sirt Inhibitor in Coffee: Isolation, Confirmation and Synthesis of Javamide-II (N-Caffeoyltryptophan) as Sirt1/2 Inhibitor

    PubMed Central

    Park, Jae B.

    2016-01-01

    Recent studies suggest that Sirt inhibition may have beneficial effects on several human diseases such as neurodegenerative diseases and cancer. Coffee is one of most popular beverages with several positive health effects. Therefore, in this paper, potential Sirt inhibitors were screened using coffee extract. First, HPLC was utilized to fractionate coffee extract, then screened using a Sirt1/2 inhibition assay. The screening led to the isolation of a potent Sirt1/2 inhibitor, whose structure was determined as javamide-II (N-caffeoyltryptophan) by NMR. For confirmation, the amide was chemically synthesized and its capacity of inhibiting Sirt1/2 was also compared with the isolated amide. Javamide-II inhibited Sirt2 (IC50; 8.7μM) better than Sirt1(IC50; 34μM). Since javamide-II is a stronger inhibitor for Sirt2 than Sirt1. The kinetic study was performed against Sirt2. The amide exhibited noncompetitive Sirt2 inhibition against the NAD+ (Ki = 9.8 μM) and showed competitive inhibition against the peptide substrate (Ki = 5.3 μM). Also, a docking simulation showed stronger binding pose of javamide-II to Sirt2 than AGK2. In cellular levels, javamide-II was able to increase the acetylation of total lysine, cortactin and histone H3 in neuronal NG108-15 cells. In the same cells, the amide also increased the acetylation of lysine (K382) in p53, but not (K305). This study suggests that Javamide-II found in coffee may be a potent Sirt1/2 inhibitor, probably with potential use in some conditions of human diseases. PMID:26986569

  2. High-resolution structure of human carbonic anhydrase II complexed with acetazolamide reveals insights into inhibitor drug design.

    PubMed

    Sippel, Katherine H; Robbins, Arthur H; Domsic, John; Genis, Caroli; Agbandje-McKenna, Mavis; McKenna, Robert

    2009-10-01

    The crystal structure of human carbonic anhydrase II (CA II) complexed with the inhibitor acetazolamide (AZM) has been determined at 1.1 A resolution and refined to an R(cryst) of 11.2% and an R(free) of 14.7%. As observed in previous CA II-inhibitor complexes, AZM binds directly to the zinc and makes several key interactions with active-site residues. The high-resolution data also showed a glycerol molecule adjacent to the AZM in the active site and two additional AZMs that are adventitiously bound on the surface of the enzyme. The co-binding of AZM and glycerol in the active site demonstrate that given an appropriate ring orientation and substituents, an isozyme-specific CA inhibitor may be developed.

  3. In silico modification of suberoylanilide hydroxamic acid (SAHA) as potential inhibitor for class II histone deacetylase (HDAC)

    PubMed Central

    2011-01-01

    Background The cervical cancer is the second most prevalent cancer for the woman in the world. It is caused by the oncogenic human papilloma virus (HPV). The inhibition activity of histone deacetylase (HDAC) is a potential strategy for cancer therapy. Suberoylanilide hydroxamic acid (SAHA) is widely known as a low toxicity HDAC inhibitor. This research presents in silico SAHA modification by utilizing triazole, in order to obtain a better inhibitor. We conducted docking of the SAHA inhibitor and 12 modified versions to six class II HDAC enzymes, and then proceeded with drug scanning of each one of them. Results The docking results show that the 12 modified inhibitors have much better binding affinity and inhibition potential than SAHA. Based on drug scan analysis, six of the modified inhibitors have robust pharmacological attributes, as revealed by drug likeness, drug score, oral bioavailability, and toxicity levels. Conclusions The binding affinity, free energy and drug scan screening of the best inhibitors have shown that 1c and 2c modified inhibitors are the best ones to inhibit class II HDAC. PMID:22373132

  4. Saccharin Sulfonamides as Inhibitors of Carbonic Anhydrases I, II, VII, XII, and XIII

    PubMed Central

    Morkūnaitė, Vaida; Baranauskienė, Lina; Zubrienė, Asta; Trapencieris, Pēteris

    2014-01-01

    A series of modified saccharin sulfonamides have been designed as carbonic anhydrase (CA) inhibitors and synthesized. Their binding to CA isoforms I, II, VII, XII, and XIII was measured by the fluorescent thermal shift assay (FTSA) and isothermal titration calorimetry (ITC). Saccharin bound the CAs weakly, exhibiting the affinities of 1–10 mM for four CAs except CA I where binding could not be detected. Several sulfonamide-bearing saccharines exhibited strong affinities of 1–10 nM towards particular CA isoforms. The functional group binding Gibbs free energy additivity maps are presented which may provide insights into the design of compounds with increased affinity towards selected CAs. PMID:25276805

  5. Design of composite inhibitors targeting glutamate carboxypeptidase II: the importance of effector functionalities

    PubMed Central

    Novakova, Zora; Cerny, Jiri; Choy, Cindy J.; Nedrow, Jessie; Choi, Joeseph K.; Lubkowski, Jacek; Berkman, Clifford E.; Barinka, Cyril

    2015-01-01

    Inhibitors targeting human glutamate carboxypeptidase II (GCPII) typically consist of a P1’ glutamate-derived binding module, which warrants the high-affinity and specificity, linked to an effector function that is positioned within the entrance funnel of the enzyme. Here we present a comprehensive structural and computational study aimed at dissecting the importance of the effector function for GCPII binding and affinity. To this end we determined crystal structures of human GCPII in complex with a series of phosphoramidate-based inhibitors harboring effector functions of diverse physicochemical characteristics. Our data shows that higher binding affinities of phosphoramidates, when compared to matching phosphonates, are linked to the presence of additional hydrogen bonds between Glu424 and Gly518 of the enzyme and the amide group of the phosphoramidate. While the positioning of the P1’ glutamate-derived module within the S1’ pocket of GCPII is invariant, interaction interfaces between effector functions and residues lining the entrance funnel are highly varied, with the positively charged arginine patch defined by Arg463, Arg534, Arg536, being the only ‘hot-spot’ common to several studied complexes. This variability stems in part from the fact that the effector/GCPII interfaces generally encompass isolated areas of non-polar residues within the entrance funnel and resulting van der Waals contacts lack the directionality typical for hydrogen-bonding interactions. Presented data unravel a complexity of binding modes of inhibitors within non-prime site(s) of GCPII and can be exploited for the design of novel GCPII-specific compounds. PMID:26460595

  6. Potato type I and II proteinase inhibitors: modulating plant physiology and host resistance.

    PubMed

    Turra, David; Lorito, Matteo

    2011-08-01

    Serine protease inhibitors (PIs) are a large and complex group of plant proteins. Members of the potato type I (Pin1) and II (Pin2) proteinase inhibitor families are among the first and most extensively characterized plant PIs. Many insects and phytopathogenic microorganisms use intracellular and extracellular serine proteases playing important roles in pathogenesis. Plants, however, are able to fight these pathogens through the activation of an intricate defence system that leads to the accumulation of various PIs, including Pin1 and Pin2. Several transgenic plants over-expressing members of the Pin1 and Pin2 families have been obtained in the last twenty years and their enhanced defensive capabilities demonstrated against insects, fungi and bacteria. Furthermore, Pin1 and Pin2 genetically engineered plants showed altered regulation of different plant physiological processes (e.g., dehydratation response, programmed cell death, plant growth, trichome density and branching), supporting an endogenous role in various plant species in addition to the well established defensive one. This review summarizes the current knowledge about Pin1 and Pin2 structure, the role of these proteins in plant defence and physiology, and their potential exploitation in biotechnology.

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

    PubMed

    Prohaska, Thomas A; Wahlmüller, Felix C; Furtmüller, Margareta; Geiger, Margarethe

    2012-01-01

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

  8. In silico approaches to identify the potential inhibitors of glutamate carboxypeptidase II (GCPII) for neuroprotection.

    PubMed

    Naushad, Shaik Mohammad; Janaki Ramaiah, M; Stanley, Balraj Alex; Prasanna Lakshmi, S; Vishnu Priya, J; Hussain, Tajamul; Alrokayan, Salman A; Kutala, Vijay Kumar

    2016-10-07

    To develop a potential inhibitor for glutamate carboxypeptidase II (GCPII) effective against all the eight common genetic variants reported, PyMOL molecular visualization system was used to generate models of variants using the crystal structure of GCPII i.e. 2OOT as a template. High-throughput virtual screening of 29 compounds revealed differential efficacy across the eight genetic variants (pIC50: 4.70 to 10.22). Pharmacophore analysis and quantitative structure-activity relationship (QSAR) studies revealed a urea-based N-acetyl aspartyl glutamate (NAAG) analogue as more potent inhibitor, which was effective across all the genetic variants of GCPII as evidenced by glide scores (-4.32 to -7.08) and protein-ligand interaction plots (13 interactions in wild GCPII). This molecule satisfied Lipinski rule of five and rule of three for drug-likeliness. Being a NAAG-analogue, this molecule might confer neuroprotection by inhibiting glutamatergic neurotransmission mediated by N-acetylated alpha-linked acidic dipeptidase (NAALADase), a splice variant of GCPII.

  9. Selective class II HDAC inhibitors impair myogenesis by modulating the stability and activity of HDAC–MEF2 complexes

    PubMed Central

    Nebbioso, Angela; Manzo, Fabio; Miceli, Marco; Conte, Mariarosaria; Manente, Lucrezia; Baldi, Alfonso; De Luca, Antonio; Rotili, Dante; Valente, Sergio; Mai, Antonello; Usiello, Alessandro; Gronemeyer, Hinrich; Altucci, Lucia

    2009-01-01

    Histone deacetylase (HDAC) inhibitors are promising new epi-drugs, but the presence of both class I and class II enzymes in HDAC complexes precludes a detailed elucidation of the individual HDAC functions. By using the class II-specific HDAC inhibitor MC1568, we separated class I- and class II-dependent effects and defined the roles of class II enzymes in muscle differentiation in cultured cells and in vivo. MC1568 arrests myogenesis by (i) decreasing myocyte enhancer factor 2D (MEF2D) expression, (ii) by stabilizing the HDAC4–HDAC3–MEF2D complex, and (iii) paradoxically, by inhibiting differentiation-induced MEF2D acetylation. In vivo MC1568 shows an apparent tissue-selective HDAC inhibition. In skeletal muscle and heart, MC1568 inhibits the activity of HDAC4 and HDAC5 without affecting HDAC3 activity, thereby leaving MEF2–HDAC complexes in a repressed state. Our results suggest that HDAC class II-selective inhibitors might have a therapeutic potential for the treatment of muscle and heart diseases. PMID:19498465

  10. Dominant lethal mutations of topoisomerase II inhibitors etoposide and merbarone in male mice: a mechanistic study.

    PubMed

    Attia, Sabry M

    2012-05-01

    Two topoisomerase II inhibitors, etoposide and merbarone, were tested for the induction of dominant lethal mutations in male mice. Etoposide was administered at a dosage of 30 or 60 mg/kg. Merbarone was administered at a dosage of 40 or 80 mg/kg. These males were mated at weekly intervals to virgin females for 6 weeks. In the present experiments, regardless of the agent, spermatids appeared to be the most sensitive germ-cell stage to dominant lethal induction. Etoposide and merbarone clearly induced dominant lethal mutations in the early spermatid stage only with the highest tested doses. The mutagenic effects were also directly correlated with reactive oxygen species accumulation as an obvious increase in 2',7'-dichlorofluorescein fluorescence level was noted in the sperm of animals treated with higher doses of etoposide and merbarone. Treatment of male mice with N-acetylcysteine significantly protected mice from etoposide- and merbarone-induced dominant lethality. Moreover, N-acetylcysteine treatment had no antagonizing effect on etoposide- and merbarone-induced topoisomerase II inhibition. Overall, this study provides for the first time that etoposide and merbarone induce dominant lethal mutations in the early spermatid stage through a mechanism that involves increases in oxidative stress. The demonstrated mutagenicity profile of etoposide and merbarone may support further development of effective chemotherapy with less mutagenicity.

  11. Identification of a better Homo sapiens Class II HDAC inhibitor through binding energy calculations and descriptor analysis.

    PubMed

    Tambunan, Usman Sumo Friend; Wulandari, Evi Kristin

    2010-10-15

    Human papillomaviruses (HPVs) are the most common on sexually transmitted viruses in the world. HPVs are responsible for a large spectrum of deseases, both benign and malignant. The certain types of HPV are involved in the development of cervical cancer. In attemps to find additional drugs in the treatment of cervical cancer, inhibitors of the histone deacetylases (HDAC) have received much attention due to their low cytotoxic profiles and the E6/E7 oncogene function of human papilomavirus can be completely by passed by HDAC inhibition. The histone deacetylase inhibitors can induce growth arrest, differentiation and apoptosis of cancer cells. HDAC class I and class II are considered the main targets for cancer. Therefore, the six HDACs class II was modeled and about two inhibitors (SAHA and TSA) were docked using AutoDock4.2, to each of the inhibitor in order to identify the pharmacological properties. Based on the results of docking, SAHA and TSA were able to bind with zinc ion in HDACs models as a drug target. SAHA was satisfied almost all the properties i.e., binding affinity, the Drug-Likeness value and Drug Score with 70% oral bioavailability and the carbonyl group of these compound fits well into the active site of the target where the zinc is present. Hence, SAHA could be developed as potential inhibitors of class II HDACs and valuable cervical cancer drug candidate.

  12. Angiotensin II receptor antagonists and heart failure: angiotensin-converting-enzyme inhibitors remain the first-line option.

    PubMed

    2005-10-01

    (1) Some angiotensin-converting-enzyme inhibitors (ACE inhibitors) reduce mortality in patients with heart failure (captopril, enalapril, ramipril and trandolapril), and in patients with recent myocardial infarction and heart failure or marked left ventricular dysfunction (captopril, ramipril and trandolapril). (2) Angiotensin II receptor antagonists, otherwise known as angiotensin receptor blockers, have haemodynamic effects similar to ACE inhibitors, but differ in their mechanism of action and certain adverse effects. (3) Five clinical trials have evaluated angiotensin II receptor antagonists (candesartan, losartan and valsartan) in terms of their effect on mortality and on the risk of clinical deterioration in patients with symptomatic heart failure, but without severe renal failure, hyperkalemia or hypotension. In these trials, candesartan and valsartan were used at much higher doses than those recommended for the treatment of arterial hypertension. (4) In patients with heart failure who were not taking an angiotensin II receptor antagonist or an ACE inhibitor at enrollment, no significant difference was found between losartan and captopril in terms of mortality or the risk of clinical deterioration. (5) In patients with heart failure who had stopped taking an ACE inhibitor because of adverse effects, candesartan had no effect on mortality as compared with placebo, but it did reduce the risk of clinical deterioration (3 fewer hospitalisations per year per 100 patients). However, candesartan was associated with adverse effects such as renal failure and hyperkalemia, especially in patients who had experienced these same adverse effects while taking an ACE inhibitor. (6) In patients with heart failure who were already taking an ACE inhibitor, adjunctive candesartan or valsartan treatment did not influence mortality in comparison to the addition of a placebo. Adding candesartan or valsartan reduced the risk of hospitalisation (between 1 and 3 fewer hospitalisations

  13. Structure-activity relationships for analogues of the phenazine-based dual topoisomerase I/II inhibitor XR11576.

    PubMed

    Wang, Shouming; Miller, Warren; Milton, John; Vicker, Nigel; Stewart, Alistair; Charlton, Peter; Mistry, Prakash; Hardick, David; Denny, William A

    2002-02-11

    As part of a programme to identify further analogues of the dual topo I/II inhibitor XR11576, we describe here the syntheses and SAR studies of various 'minimal' and 3,4-benzofused phenazine chromophores of the phenazine template of XR11576.

  14. Effects of treatment with an Hsp90 inhibitor in tumors based on 15 phase II clinical trials

    PubMed Central

    Wang, He; Lu, Mingjie; Yao, Mengqian; Zhu, Wei

    2016-01-01

    Heat shock protein (Hsp)90 serves as a chaperone protein that promotes the proper folding of proteins involved in a variety of signal transduction processes involved in cell growth. Hsp90 inhibitors, which inhibit the activity of critical client proteins, have emerged as the accessory therapeutic agents for multiple human cancer types. To better understand the effects of Hsp90 inhibitors in cancer treatment, the present study reviewed 15 published phase II clinical trials to investigate whether Hsp90 inhibitors will benefit patients with cancer. Information of complete response, partial response, stable disease, objective response and objective response rate was collected to evaluate clinical outcomes. Overall, Hsp90 inhibitors are effective against a variety of oncogene-addicted cancers, including those that have developed resistance to specific receptors. PMID:27602225

  15. Recent advances in inhibitors of bacterial fatty acid synthesis type II (FASII) system enzymes as potential antibacterial agents.

    PubMed

    Wang, Yi; Ma, Shutao

    2013-10-01

    Bacterial infections are a constant and serious threat to human health. With the increase of multidrug resistance of clinically pathogenic bacteria, common antibiotic therapies have been less effective. Fatty acid synthesis type II (FASII) system enzymes are essential for bacterial membrane lipid biosynthesis and represent increasingly promising targets for the discovery of antibacterial agents with new mechanisms of action. This review highlights recent advances in inhibitors of bacterial FASII as potential antibacterial agents, paying special attention to the activities, mechanisms, and structure-activity relationships of those inhibitors that mainly target β-ketoacyl-ACP synthase, β-ketoacyl-ACP reductase, β-hydroxyacyl-ACP dehydratase, and enoyl-ACP reductase. Although inhibitors with low nanomolar and selective activity against various bacterial FASII have entered clinical trials, further research is needed to expand upon both available and yet unknown scaffolds to identify new FASII inhibitors that may have antibacterial potential, particularly against resistant bacterial strains.

  16. Rational design of urea-based glutamate carboxypeptidase II (GCPII) inhibitors as versatile tools for specific drug targeting and delivery.

    PubMed

    Tykvart, Jan; Schimer, Jiří; Bařinková, Jitka; Pachl, Petr; Poštová-Slavětínská, Lenka; Majer, Pavel; Konvalinka, Jan; Šácha, Pavel

    2014-08-01

    Glutamate carboxypeptidase II (GCPII), also known as prostate specific membrane antigen (PSMA), is an established prostate cancer marker and is considered a promising target for specific anticancer drug delivery. Low-molecular-weight inhibitors of GCPII are advantageous specific ligands for this purpose. However, they must be modified with a linker to enable connection of the ligand with an imaging molecule, anticancer drug, and/or nanocarrier. Here, we describe a structure-activity relationship (SAR) study of GCPII inhibitors with linkers suitable for imaging and drug delivery. Structure-assisted inhibitor design and targeting of a specific GCPII exosite resulted in a 7-fold improvement in Ki value compared to the parent structure. X-ray structural analysis of the inhibitor series led to the identification of several inhibitor binding modes. We also optimized the length of the inhibitor linker for effective attachment to a biotin-binding molecule and showed that the optimized inhibitor could be used to target nanoparticles to cells expressing GCPII.

  17. Synthesis and evaluation of 18F-labeled ATP competitive inhibitors of topoisomerase II as probes for imaging topoisomerase II expression

    PubMed Central

    Daumar, Pierre; Zeglis, Brian M.; Ramos, Nicholas; Divilov, Vadim; Sevak, Kuntal Kumar; Pillarsetty, NagaVaraKishore; Lewis, Jason S.

    2015-01-01

    Type II topoisomerase (Topo-II) is an ATP-dependent enzyme that is essential in the transcription, replication, and chromosome segregation processes and, as such, represents an attractive target for cancer therapy. Numerous studies indicate that the response to treatment with Topo-II inhibitors is highly dependent on both the levels and the activity of the enzyme. Consequently, a non-invasive assay to measure tumoral Topo-II levels has the potential to differentiate responders from non-responders. With the ultimate goal of developing a radiofluorinated tracer for positron emission tomography (PET) imaging, we have designed, synthesized, and evaluated a set of fluorinated compounds based on the structure of the ATP-competitive Topo-II inhibitor QAP1. Compounds 18 and 19b showed inhibition of Topo-II in in vitro assays and exhibited moderate, Topo-II level dependent cytotoxicity in SK-BR-3 and MCF-7 cell lines. Based on these results, 18F-labeled analogs of these two compounds were synthesized and evaluated as PET probes for imaging Topo-II overexpression in mice bearing SK-BR-3 xenografts. [18F]-18 and [18F]-19b were synthesized from their corresponding protected tosylated derivatives by fluorination and subsequent deprotection. Small animal PET imaging studies indicated that both compounds do not accumulate in tumors and exhibit poor pharmacokinetics, clearing from the blood pool very rapidly and getting metabolized over. The insights gained from the current study will surely aid in the design and construction of future generations of PET agents for the non-invasive delineation of Topo-II expression. PMID:25240701

  18. A common mechanism links differently acting complex II inhibitors to cardioprotection: modulation of mitochondrial reactive oxygen species production.

    PubMed

    Dröse, Stefan; Bleier, Lea; Brandt, Ulrich

    2011-05-01

    In this study, we have analyzed the effect of different cardioprotective complex II inhibitors on the mitochondrial production of reactive oxygen species (ROS) because ROS seem to be essential for signaling during preconditioning to prevent ischemia/reperfusion injury. Despite different binding sites and concentrations required for half-maximal inhibition-ranging from nanomolar for the Q site inhibitor atpenin A5 to millimolar for the succinate analog malonate-all inhibitors modulated ROS production in the same ambivalent fashion: they promoted the generation of superoxide at the Q(o) site of complex III under conditions of "oxidant-induced reduction" but attenuated ROS generated at complex I due to reverse electron transfer. All inhibitors showed these ambivalent effects independent of the presence of K(+). These findings suggest a direct modulation of mitochondrial ROS generation during cardioprotection via complex II inhibition and question the recently proposed role of complex II as a regulatory component of the putative mitochondrial K(ATP) channel.

  19. Lead Discovery of Type II BRAF V600E Inhibitors Targeting the Structurally Validated DFG-Out Conformation Based upon Selected Fragments.

    PubMed

    Zhang, Qingwen; Zhang, Xuejin; You, Qidong

    2016-07-16

    The success of the first approved kinase inhibitor imatinib has spurred great interest in the development of type II inhibitors targeting the inactive DFG-out conformation, wherein the Phe of the DFG motif at the start of the activation loop points into the ATP binding site. Nevertheless, kinase inhibitors launched so far are heavily biased toward type I inhibitors targeting the active DFG-in conformation, wherein the Phe of the DFG motif flips by approximately 180° relative to the inactive conformation, resulting in Phe and Asp swapping their positions. Data recently obtained with structurally validated type II inhibitors supported the conclusion that type II inhibitors are more selective than type I inhibitors. In our type II BRAF V600E inhibitor lead discovery effort, we identified phenylaminopyrimidine (PAP) and unsymmetrically disubstituted urea as two fragments that are frequently presented in FDA-approved protein kinase inhibitors. We therefore defined PAP and unsymmetrically disubstituted urea as privileged fragments for kinase drug discovery. A pharmacophore for type II inhibitors, 4-phenylaminopyrimidine urea (4-PAPU), was assembled based upon these privileged fragments. Lead compound SI-046 with BRAF V600E inhibitory activity comparable to the template compound sorafenib was in turn obtained through preliminary structure-activity relationship (SAR) study. Molecular docking suggested that SI-046 is a bona fide type II kinase inhibitor binding to the structurally validated "classical DFG-out" conformation of BRAF V600E. Our privileged fragments-based approach was shown to efficiently deliver a bona fide type II kinase inhibitor lead. In essence, the theme of this article is to showcase the strategy and rationale of our approach.

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

    PubMed

    Badrinarayan, Preethi; Sastry, G Narahari

    2012-04-01

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

  1. A Phase II Study of RO4929097 Gamma-Secretase Inhibitor in Metastatic Melanoma: SWOG 0933

    PubMed Central

    Lee, Sylvia M.; Moon, James; Redman, Bruce G.; Chidiac, Tarek; Flaherty, Lawrence E.; Zha, Yuanyuan; Othus, Megan; Ribas, Antoni; Sondak, Vernon K.

    2014-01-01

    Background Aberrant Notch activation confers a proliferative advantage onto many human tumors, including melanoma. This phase II trial assessed the antitumor activity of RO4929097, a gamma-secretase inhibitor of Notch signaling, on the progression-free and overall survival of patients with advanced melanoma. Methods Chemotherapy-naïve patients with metastatic melanoma of cutaneous or unknown origin were treated with RO4929097 at a dose of 20 mg orally daily, 3 consecutive days per week. A two-step accrual design was used, with an interim analysis on the first 32 patients, and continuation of enrollment if ≥4/32 patients responded. Results Thirty-six patients from 23 institutions were enrolled; 32 patients were evaluable. RO4929097 was well-tolerated, and most toxicities were grade 1 or 2. The most common toxicities were nausea (53%), fatigue (41%), and anemia (22%). There was 1 confirmed partial response lasting 7 months, and 8 patients with stable disease lasting at least through week 12, with one of these continuing for 31 months. The 6-month PFS was 9% (95% CI: 2–22%), and 1-year OS was 50% (95% CI: 32–66%). Peripheral blood T cell assays showed no significant inhibition of IL-2 production, a surrogate pharmacodynamic marker of Notch inhibition, suggesting that the drug levels were insufficient to achieve Notch target inhibition. Conclusions RO4929097 showed minimal clinical activity against metastatic melanoma in this phase II trial, possibly due to inadequate exposure to therapeutic drug levels. While Notch inhibition remains a compelling target in melanoma, our results do not support further investigation of RO4929097 at this dose and schedule. PMID:25250858

  2. Evaluation of selenide, diselenide and selenoheterocycle derivatives as carbonic anhydrase I, II, IV, VII and IX inhibitors.

    PubMed

    Angeli, Andrea; Tanini, Damiano; Viglianisi, Caterina; Panzella, Lucia; Capperucci, Antonella; Menichetti, Stefano; Supuran, Claudiu T

    2017-04-15

    A series of selenides, diselenides and organoselenoheterocycles were evaluated as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors against the human (h) isoforms hCA I, II, IV, VII and IX, involved in a variety of diseases among which glaucoma, retinitis pigmentosa, epilepsy, arthritis and tumors etc. These investigated compounds showed inhibitory action against these isoforms and some of them were selective for inhibiting the cytosolic over the membrane-bound isoforms, thus making them interesting leads for the development of isoform-selective inhibitors.

  3. The endogenous mitochondrial complex II inhibitor malonate regulates mitochondrial ATP-sensitive potassium channels: implications for ischemic preconditioning.

    PubMed

    Wojtovich, Andrew P; Brookes, Paul S

    2008-01-01

    Ischemic preconditioning (IPC) affords cardioprotection against ischemia-reperfusion (IR) injury, and while the molecular mechanisms of IPC are debated, the mitochondrial ATP-sensitive K(+) channel (mK(ATP)) has emerged as a candidate effector for several IPC signaling pathways. The molecular identity of this channel is unknown, but significant pharmacologic overlap exists between mK(ATP) and mitochondrial respiratory complex II (succinate dehydrogenase). In this investigation, we utilized isolated cardiac mitochondria, Langendorff perfused hearts, and a variety of biochemical methods, to make the following observations: (i) The competitive complex II inhibitor malonate is formed in mitochondria under conditions resembling IPC. (ii) IPC leads to a reversible inhibition of complex II that has likely been missed in previous investigations due to the use of saturating concentrations of succinate. (iii) Malonate opens mK(ATP) channels even when mitochondria are respiring on complex I-linked substrates, suggesting an effect of this inhibitor on the mK(ATP) channel independent of complex II inhibition. Together, these observations suggest that complex II inhibition by endogenously formed malonate may represent an important activation pathway for mK(ATP) channels during IPC.

  4. Development of a Method for Converting a TAK1 Type I Inhibitor into a Type II or c-Helix-Out Inhibitor by Structure-Based Drug Design (SBDD).

    PubMed

    Muraoka, Terushige; Ide, Mitsuaki; Irie, Machiko; Morikami, Kenji; Miura, Takaaki; Nishihara, Masamichi; Kashiwagi, Hirotaka

    2016-01-01

    We have developed a method for converting a transforming growth factor-β-activated kinase 1 (TAK1) type I inhibitor into a type II or c-helix-out inhibitor by structure-based drug design (SBDD) to achieve an effective strategy for developing these different types of kinase inhibitor in parallel. TAK1 plays a key role in inflammatory and immune signaling, and is therefore considered to be an attractive molecular target for the treatment of human diseases (inflammatory disease, cancer, etc.). We have already reported novel type I TAK1 inhibitor, so we utilized its X-ray information to design a new chemical class type II and c-helix-out inhibitors. To develop the type II inhibitor, we superimposed the X-ray structure of our reported type I inhibitor onto a type II compound that inhibits multiple kinases, and used SBDD to design a new type II inhibitor. For the TAK1 c-helix-out inhibitor, we utilized the X-ray structure of a b-Raf c-helix-out inhibitor to design compounds, because TAK1 is located close to b-Raf in the Sugen kinase tree, so we considered that TAK1 would, similarly to b-Raf, form a c-helix-out conformation. The X-ray crystal structure of the inhibitors in complex with TAK1 confirmed the binding modes of the compounds we designed. This report is notable for being the first discovery of a c-helix-out inhibitor against TAK1.

  5. EZH2 inhibition sensitizes BRG1 and EGFR mutant lung tumors to TopoII inhibitors

    PubMed Central

    Fillmore, Christine M.; Xu, Chunxiao; Desai, Pooja T.; Berry, Joanne M.; Rowbotham, Samuel P.; Lin, Yi-Jang; Zhang, Haikuo; Marquez, Victor E.; Hammerman, Peter S.; Wong, Kwok-Kin; Kim, Carla F.

    2014-01-01

    SUMMARY Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide1. Chemotherapies such as the topoisomerase II inhibitor (TopoIIi) etoposide effectively reduce disease in a minority of NSCLC patients2,3; therefore, alternative drug targets, including epigenetic enzymes, are under consideration for therapeutic intervention4. A promising potential epigenetic target is the methyltransferase EZH2, which in the context of the Polycomb Repressive Complex 2 (PRC2) is well known to tri-methylate Histone H3 at lysine 27 (H3K27me3) and elicit gene silencing5. Here, we demonstrate that EZH2 inhibition (EZH2i) had differential effects on TopoIIi response of NSCLCs in vitro and in vivo. EGFR and BRG1 mutations were genetic biomarkers that predicted enhanced sensitivity to TopoIIi in response to EZH2i. BRG1 loss-of-function mutant tumors responded to EZH2i with increased S phase, anaphase bridging, apoptosis, and TopoIIi sensitivity. Conversely, EGFR and BRG1 wild-type tumors up-regulated BRG1 in response to EZH2i and ultimately became more resistant to TopoIIi. EGFR gain-of-function mutant tumors were also sensitive to dual EZH2i and TopoIIi, due to genetic antagonism between EGFR and BRG1. These findings suggest an exciting opportunity for precision medicine in the genetically complex disease of NSCLC. PMID:25629630

  6. Phase II randomised discontinuation trial of the MET/VEGF receptor inhibitor cabozantinib in metastatic melanoma

    PubMed Central

    Daud, Adil; Kluger, Harriet M; Kurzrock, Razelle; Schimmoller, Frauke; Weitzman, Aaron L; Samuel, Thomas A; Moussa, Ali H; Gordon, Michael S; Shapiro, Geoffrey I

    2017-01-01

    Background: A phase II randomised discontinuation trial assessed cabozantinib (XL184), an orally bioavailable inhibitor of tyrosine kinases including VEGF receptors, MET, and AXL, in a cohort of patients with metastatic melanoma. Methods: Patients received cabozantinib 100 mg daily during a 12-week lead-in. Patients with stable disease (SD) per Response Evaluation Criteria in Solid Tumours (RECIST) at week 12 were randomised to cabozantinib or placebo. Primary endpoints were objective response rate (ORR) at week 12 and postrandomisation progression-free survival (PFS). Results: Seventy-seven patients were enroled (62% cutaneous, 30% uveal, and 8% mucosal). At week 12, the ORR was 5% 39% of patients had SD. During the lead-in phase, reduction in target lesions from baseline was seen in 55% of evaluable patients overall and in 59% of evaluable patients with uveal melanoma. Median PFS after randomisation was 4.1 months with cabozantinib and 2.8 months with placebo (hazard ratio of 0.59; P=0.284). Median PFS from study day 1 was 3.8 months, 6-month PFS was 33%, and median overall survival was 9.4 months. The most common grade 3/4 adverse events were fatigue (14%), hypertension (10%), and abdominal pain (8%). One treatment-related death was reported from peritonitis due to diverticular perforation. Conclusions: Cabozantinib has clinical activity in patients with metastatic melanoma, including uveal melanoma. Further clinical investigation is warranted. PMID:28103611

  7. Simplified AIP-II Peptidomimetics Are Potent Inhibitors of Staphylococcus aureus AgrC Quorum Sensing Receptors.

    PubMed

    Vasquez, Joseph K; Tal-Gan, Yftah; Cornilescu, Gabriel; Tyler, Kimberly A; Blackwell, Helen E

    2017-02-16

    The bacterial pathogen Staphylococcus aureus controls many aspects of virulence by using the accessory gene regulator (agr) quorum sensing (QS) system. The agr system is activated by a macrocyclic peptide signal known as an autoinducing peptide (AIP). We sought to develop structurally simplified mimetics of AIPs for use as chemical tools to study QS in S. aureus. Herein, we report new peptidomimetic AgrC receptor inhibitors based on a tail-truncated AIP-II peptide that have almost analogous inhibitory activities to the parent peptide. Structural comparison of one of these peptidomimetics to the parent peptide and a highly potent, all-peptide-derived, S. aureus agr inhibitor (AIP-III D4A) revealed a conserved hydrophobic motif and overall amphipathic nature. Our results suggest that the AIP scaffold is amenable to structural mimicry and minimization for the development of synthetic agr inhibitors.

  8. Palladium(II) and zinc(II) complexes of neutral [N2O2] donor Schiff bases derived from furfuraldehyde: synthesis, characterization, fluorescence and corrosion inhibitors of ligands.

    PubMed

    Ali, Omyma A M

    2014-11-11

    Metal complexes of Schiff bases derived from furfuraldehyde and 4,5-dimethyl-1,2-phenylendiamine (L1) or 4,5-dichloro-1,2-phenylendiamine (L2) have been reported and characterized based on elemental analyses, IR, 1H NMR, UV-Vis, magnetic moment, molar conductance and thermal analysis. The complexes are found to have the formulae [PdL1-2]Cl2 and [ZnL1-2](AcO)2·H2O. The molar conductance data reveal that Pd(II) and Zn(II) chelates are ionic in nature and are of the type 2:1 electrolytes. The spectral data are consistent with a square planar and tetrahedral geometry around Pd(II) and Zn(II), respectively, in which the ligands act as tetradentate ligands. The thermal behavior of some chelates is studied and the activation thermodynamic parameters are calculated using Coats-Redfern method. The corrosion inhibition of stainless steel types 410 and 304 in 1 M HCl using the synthesized Schiff bases as inhibitors have been studied by weight loss method. The obtained data considered these ligands as efficient corrosion inhibitors. The ligands and their metal complexes exhibited considerable antibacterial activity against Staphylococcusaureus, and Escherichiacoli and antifungal activity against Candida albicans.

  9. Palladium(II) and zinc(II) complexes of neutral [N2O2] donor Schiff bases derived from furfuraldehyde: Synthesis, characterization, fluorescence and corrosion inhibitors of ligands

    NASA Astrophysics Data System (ADS)

    Ali, Omyma A. M.

    2014-11-01

    Metal complexes of Schiff bases derived from furfuraldehyde and 4,5-dimethyl-1,2-phenylendiamine (L1) or 4,5-dichloro-1,2-phenylendiamine (L2) have been reported and characterized based on elemental analyses, IR, 1H NMR, UV-Vis, magnetic moment, molar conductance and thermal analysis. The complexes are found to have the formulae [PdL1-2]Cl2 and [ZnL1-2](AcO)2·H2O. The molar conductance data reveal that Pd(II) and Zn(II) chelates are ionic in nature and are of the type 2:1 electrolytes. The spectral data are consistent with a square planar and tetrahedral geometry around Pd(II) and Zn(II), respectively, in which the ligands act as tetradentate ligands. The thermal behavior of some chelates is studied and the activation thermodynamic parameters are calculated using Coats-Redfern method. The corrosion inhibition of stainless steel types 410 and 304 in 1 M HCl using the synthesized Schiff bases as inhibitors have been studied by weight loss method. The obtained data considered these ligands as efficient corrosion inhibitors. The ligands and their metal complexes exhibited considerable antibacterial activity against Staphylococcusaureus, and Escherichiacoli and antifungal activity against Candida albicans.

  10. Carbonic anhydrase inhibitors. Interaction of isozymes I, II, IV, V, and IX with carboxylates.

    PubMed

    Innocenti, Alessio; Vullo, Daniela; Scozzafava, Andrea; Casey, Joseph R; Supuran, Claudiut

    2005-02-01

    A detailed inhibition study of five carbonic anhydrase (CA, EC 4.2.1.1) isozymes with carboxylates including aliphatic (formate, acetate), dicarboxylic (oxalate, malonate), hydroxy/keto acids (l-lactate, l-malate, pyruvate), tricarboxylic (citrate), or aromatic (benzoate, tetrafluorobenzoate) representatives, some of which are important intermediates in the Krebs cycle, is presented. The cytosolic isozyme hCA I was strongly activated by acetate, oxalate, pyruvate, l-lactate, and citrate (K(A) around 0.1 microM), whereas formate, malonate, malate, and benzoate were weaker activators (K(A) in the range 0.1-1mM). The cytosolic isozyme hCA II was weakly inhibited by all the investigated anions, with inhibition constants in the range of 0.03-24 mM. The membrane-associated isozyme hCA IV was the most sensitive to inhibition by carboxylates, showing a K(I) of 99 nM for citrate and oxalate, of 2.8 microM for malonate and of 14.5 microM for pyruvate among others. The mitochondrial isozyme hCA V was weakly inhibited by all these carboxylates (K(I)s in the range of 1.67-25.9 mM), with the best inhibitor being citrate (K(I) of 1.67 mM), whereas this is the most resistant CA isozyme to pyruvate inhibition (K(I) of 5.5mM), which may be another proof that CA V is the isozyme involved in the transfer of acetyl groups from the mitochondrion to the cytosol for the provision of substrate(s) for de novo lipogenesis. Furthermore, the relative resistance of CA V to inhibition by pyruvate may be an evolutionary adaptation of this mitochondrial isozyme to the presence of high concentrations of this anion within this organelle. The transmembrane, tumor-associated isozyme hCA IX was similar to isozyme II in its slight inhibition by all these anions (K(I) in the range of 1.12-7.42 mM), except acetate, lactate, and benzoate, which showed a K(I)>150 mM. The lactate insensitivity of CA IX also represents an interesting finding, since it is presumed that this isozyme evolved in such a way as to

  11. Phase II study of tivozanib, an oral VEGFR inhibitor, in patients with recurrent glioblastoma.

    PubMed

    Kalpathy-Cramer, Jayashree; Chandra, Vyshak; Da, Xiao; Ou, Yangming; Emblem, Kyrre E; Muzikansky, Alona; Cai, Xuezhu; Douw, Linda; Evans, John G; Dietrich, Jorg; Chi, Andrew S; Wen, Patrick Y; Stufflebeam, Stephen; Rosen, Bruce; Duda, Dan G; Jain, Rakesh K; Batchelor, Tracy T; Gerstner, Elizabeth R

    2017-02-01

    Targeting tumor angiogenesis is a potential therapeutic strategy for glioblastoma because of its high vascularization. Tivozanib is an oral pan-VEGF receptor tyrosine kinase inhibitor that hits a central pathway in glioblastoma angiogenesis. We conducted a phase II study to test the effectiveness of tivozanib in patients with recurrent glioblastoma. Ten adult patients were enrolled and treated with tivozanib 1.5 mg daily, 3 weeks on/1 week off in 28-day cycles. Brain MRI and blood biomarkers of angiogenesis were performed at baseline, within 24-72 h of treatment initiation, and monthly thereafter. Dynamic contrast enhanced MRI, dynamic susceptibility contrast MRI, and vessel architecture imaging were used to assess vascular effects. Resting state MRI was used to assess brain connectivity. Best RANO criteria responses were: 1 complete response, 1 partial response, 4 stable diseases, and 4 progressive disease (PD). Two patients were taken off study for toxicity and 8 patients were taken off study for PD. Median progression-free survival was 2.3 months and median overall survival was 8.1 months. Baseline abnormal tumor vascular permeability, blood flow, tissue oxygenation and plasma sVEGFR2 significantly decreased and plasma PlGF and VEGF increased after treatment, suggesting an anti-angiogenic effect of tivozanib. However, there were no clear structural changes in vasculature as vessel caliber and enhancing tumor volume did not significantly change. Despite functional changes in tumor vasculature, tivozanib had limited anti-tumor activity, highlighting the limitations of anti-VEGF monotherapy. Future studies in glioblastoma should leverage the anti-vascular activity of agents targeting VEGF to enhance the activity of other therapies.

  12. Biological Evaluation of Benzothiazole Ethyl Urea Inhibitors of Bacterial Type II Topoisomerases

    PubMed Central

    Stokes, Neil R.; Thomaides-Brears, Helena B.; Barker, Stephanie; Bennett, James M.; Berry, Joanne; Collins, Ian; Czaplewski, Lloyd G.; Gamble, Vicki; Lancett, Paul; Logan, Alastair; Lunniss, Christopher J.; Peasley, Hilary; Pommier, Stéphanie; Price, Daniel; Smee, Carol

    2013-01-01

    The type II topoisomerases DNA gyrase (GyrA/GyrB) and topoisomerase IV (ParC/ParE) are well-validated targets for antibacterial drug discovery. Because of their structural and functional homology, these enzymes are amenable to dual targeting by a single ligand. In this study, two novel benzothiazole ethyl urea-based small molecules, designated compound A and compound B, were evaluated for their biochemical, antibacterial, and pharmacokinetic properties. The two compounds inhibited the ATPase activity of GyrB and ParE with 50% inhibitory concentrations of <0.1 μg/ml. Prevention of DNA supercoiling by DNA gyrase was also observed. Both compounds potently inhibited the growth of a range of bacterial organisms, including staphylococci, streptococci, enterococci, Clostridium difficile, and selected Gram-negative respiratory pathogens. MIC90s against clinical isolates ranged from 0.015 μg/ml for Streptococcus pneumoniae to 0.25 μg/ml for Staphylococcus aureus. No cross-resistance with common drug resistance phenotypes was observed. In addition, no synergistic or antagonistic interactions between compound A or compound B and other antibiotics, including the topoisomerase inhibitors novobiocin and levofloxacin, were detected in checkerboard experiments. The frequencies of spontaneous resistance for S. aureus were <2.3 × 10−10 with compound A and <5.8 × 10−11 with compound B at concentrations equivalent to 8× the MICs. These values indicate a multitargeting mechanism of action. The pharmacokinetic properties of both compounds were profiled in rats. Following intravenous administration, compound B showed approximately 3-fold improvement over compound A in terms of both clearance and the area under the concentration-time curve. The measured oral bioavailability of compound B was 47.7%. PMID:24041906

  13. Cobalt(II) β-ketoaminato complexes as novel inhibitors of neuroinflammation.

    PubMed

    Madeira, Jocelyn M; Beloukhina, Natalia; Boudreau, Kalun; Boettcher, Tyson A; Gurley, Lydia; Walker, Douglas G; McNeil, W Stephen; Klegeris, Andis

    2012-02-15

    Neuroinflammation contributes to the pathogenesis of neurological disorders including stroke, head trauma, multiple sclerosis, amyotrophic lateral sclerosis as well as age-associated neurodegenerative disorders including Alzheimer's and Parkinson's diseases. Therefore, anti-inflammatory drugs could be used to slow the progression of these diseases. We studied the anti-neuroinflammatory activity of four novel square planar cobalt(II) compounds bearing tetradentate β-ketoaminato ligands with variation in the number of CF(3) ligand substituents, as well as their corresponding unmetallated organic ligands. Cobalt (Co) complexes were consistently more active than their corresponding ligands. One of the complexes, L(3)Co at concentrations (1-10 μM) that were not toxic to cells, significantly reduced cytotoxic secretions by human monocytic THP-1 cells, astrocytoma U-373 MG cells, and primary human microglia. This anti-neurotoxic action of L(3)Co was reduced by SP600125 and PD98059, selective inhibitors of c-Jun NH2-terminal kinase (JNK) and extracellular signal regulated kinase (ERK) kinase (MEK)1/2 respectively. L(3)Co had no effect on secretion of monocyte chemotactic protein-1 (MCP-1) by THP-1 cells, but it inhibited the NADPH oxidase-dependent respiratory burst activity of differentiated human HL-60 cells. L(3)Co upregulated heme oxygenase-1 (HOX-1) expression by THP-1 cells, which may be one of the molecular mechanisms responsible for its anti-inflammatory properties. Two of the Co compounds tested showed activity only at high concentrations (50 μM), but L(2)Co was highly toxic to all cell types used. Select Co complexes, such as L(3)Co, may exhibit pharmacological properties beneficial in human diseases involving neuroinflammatory processes. Further studies of the in vivo efficacy, safety and pharmacokinetics of L(3)Co are warranted.

  14. The PP2A inhibitor I2PP2A is essential for sister chromatid segregation in oocyte meiosis II.

    PubMed

    Chambon, Jean-Philippe; Touati, Sandra A; Berneau, Stéphane; Cladière, Damien; Hebras, Céline; Groeme, Rachel; McDougall, Alex; Wassmann, Katja

    2013-03-18

    Haploid gametes are generated through two consecutive meiotic divisions, with the segregation of chromosome pairs in meiosis I and sister chromatids in meiosis II. Separase-mediated stepwise removal of cohesion, first from chromosome arms and later from the centromere region, is a prerequisite for maintaining sister chromatids together until their separation in meiosis II [1]. In all model organisms, centromeric cohesin is protected from separase-dependent removal in meiosis I through the activity of PP2A-B56 phosphatase, which is recruited to centromeres by shugoshin/MEI-S332 (Sgo) [2-5]. How this protection of centromeric cohesin is removed in meiosis II is not entirely clear; we find that all the PP2A subunits remain colocalized with the cohesin subunit Rec8 at the centromere of metaphase II chromosomes. Here, we show that sister chromatid separation in oocytes depends on a PP2A inhibitor, namely I2PP2A. I2PP2A colocalizes with the PP2A enzyme at centromeres at metaphase II, independently of bipolar attachment. When I2PP2A is depleted, sister chromatids fail to segregate during meiosis II. Our findings demonstrate that in oocytes I2PP2A is essential for faithful sister chromatid segregation by mediating deprotection of centromeric cohesin in meiosis II.

  15. Angiotensin II Induces a Region-Specific Hyperplasia of the Ascending Aorta Through Regulation of Inhibitor of Differentiation 3

    PubMed Central

    Owens, A. Phillip; Subramanian, Venkateswaran; Moorleghen, Jessica J.; Guo, Zhenheng; McNamara, Coleen A.; Cassis, Lisa A; Daugherty, Alan

    2010-01-01

    Rationale Angiotensin II (AngII) has diverse effects on smooth muscle cells. The diversity of effects may relate to the regional location of this cell type. Objective The aim of this study was to define whether AngII exerted divergent effects on smooth muscle cells (SMC) in the aorta and determine the role of blood pressure and specific oxidant mechanisms. Methods and Results AngII (1,000 ng/kg/min) infusion for 28 days into mice increased systolic blood pressure (SBP) and promoted medial expansion of equivalent magnitude throughout the entire aorta. Both effects were ablated by AT1a receptor deficiency. Similar increases in blood pressure by administration of norepinephrine promoted no changes in aortic medial thickness. Increased medial thickness was due to SMC expansion attributable to hypertrophy in most aortic regions, with the exception of hyperplasia of the ascending aorta. Deficiency of the p47phox component of NADPH oxidase ablated AngII-induced medial expansion in all aortic regions. Analysis of mRNA and protein throughout the aorta revealed a much higher abundance of the inhibitor of differentiation 3 (Id3) in the ascending aorta compared to all other regions. A functional role was demonstrated by Id3 deficiency inhibiting AngII-induced SMC hyperplasia of the ascending aorta. Conclusions In conclusion, AngII promotes both aortic medial hypertrophy and hyperplasia in a region-specific manner via an oxidant mechanism. The ascending aortic hyperplasia is dependent on Id3. PMID:20019328

  16. Identification and characterization of inhibitors of cytoplasmic 5'-nucleotidase cN-II issued from virtual screening.

    PubMed

    Jordheim, Lars Petter; Marton, Zsuzsanna; Rhimi, Moez; Cros-Perrial, Emeline; Lionne, Corinne; Peyrottes, Suzanne; Dumontet, Charles; Aghajari, Nushin; Chaloin, Laurent

    2013-02-15

    Clinical and preclinical observations have lead to the hypothesis that 5'-nucleotidase cN-II could constitute a therapeutic target in oncology, either per se or to increase the activity of cytotoxic nucleoside analogs. To identify potential cN-II inhibitors, we performed in silico screening of freely available chemical databases, in vitro enzymatic assays with recombinant cN-II, soaking experiments with crystals of truncated cN-II as well as biological evaluation of selected compounds, alone or in combination with cytotoxic nucleoside analogs, on cancer cells. The top ranked compounds from virtual screening included an anthraquinone derivative (AdiS) that were shown to block the enzyme activity with a K(i) of 2.0mM. Soaking experiments performed with crystals of truncated cN-II allowed to obtain crystallographic data at a resolution of 2.9 Å and indicating interaction between AdiS and F354/I152 situated in the effector site 1 of cN-II. In addition, this compound exhibited different levels of cytotoxicity in vitro on several cancer cell lines and increased the induction of apoptosis in RL cells incubated with 0.5 or 1.5 μM cladribine, 0.05 μM clofarabine or 30 μM fludarabine. Finally, AdiS showed synergy with cladribine and additivity with clofarabine. This study showed that virtual screening is a useful tool for the identification of potent cN-II inhibitors, and our biological results indicated interesting activity for one lead compound that can be further developed as therapeutics.

  17. Debate: angiotensin-converting enzyme inhibitors versus angiotensin II receptor blockers--a gap in evidence-based medicine.

    PubMed

    Ball, Stephen G; White, William B

    2003-05-22

    In this article, 2 leading physicians debate the strength of outcome data on the efficacy of angiotensin-converting enzyme (ACE) inhibitors versus angiotensin II receptor blockers (ARBs) for reducing the incidence of cardiovascular, cerebrovascular, and renovascular events. Dr. Stephen G. Ball notes that the efficacy of ACE inhibitors for reducing the risk for myocardial infarction independent of their effects on blood pressure is controversial. In the Heart Outcomes Prevention Evaluation (HOPE) study, ramipril treatment in high-risk patients was associated with a 20% reduction in the risk for myocardial infarction; mean reduction in blood pressure was 3 mm Hg for systolic blood pressure and 1 mm Hg for diastolic blood pressure. The HOPE investigators propose that the 20% reduction was much greater than would be expected based on the observed blood pressure reduction. However, a meta-regression analysis of blood pressure reduction in >20 antihypertensive therapy outcome trials found that the reduction in myocardial infarction risk with ramipril observed in HOPE was consistent with the modest blood pressure reduction seen with that agent. Nevertheless, there are convincing data for prevention of myocardial infarction with ACE inhibitors in patients with heart failure, including those with heart failure after myocardial infarction, as well as supportive evidence from studies in patients with diabetes mellitus and concomitant hypertension. On the other hand, Dr. William B. White takes the position that ARBs are well-tolerated antihypertensive agents that specifically antagonize the angiotensin II type 1 (AT(1)) receptor and provide a more complete block of the pathologic effects of angiotensin II-which are mediated via the AT(1) receptor-than ACE inhibitors. The Evaluation of Losartan in the Elderly (ELITE) II study and the Valsartan Heart Failure Trial (ValHeFT) suggest that ARBs reduce the risk for mortality in patients with congestive heart failure. The Losartan

  18. Strategic approaches to drug design. II. Modelling studies on phosphodiesterase substrates and inhibitors

    NASA Astrophysics Data System (ADS)

    Davis, A.; Warrington, B. H.; Vinter, J. G.

    1987-07-01

    Modelling studies have been carried out on the phosphodiesterase (PDE) substrates, adenosine- and guanosine-3'5'-cyclic monophosphates, and on a number of non-specific and type III-specific phosphodiesterase inhibitors. These studies have assisted the understanding of PDE substrate differentiation and the design of potent, selective PDE type III inhibitors.

  19. Carbonic anhydrase activators. The selective serotonin reuptake inhibitors fluoxetine, sertraline and citalopram are strong activators of isozymes I and II.

    PubMed

    Casini, Angela; Caccia, Silvio; Scozzafava, Andrea; Supuran, Claudiu T

    2003-08-18

    The selective serotonin reuptake inhibitors (SSRI) fluoxetine, sertraline and citalopram have been investigated for their ability to activate two carbonic anhydrase (CA) isozymes, hCA I and hCA II, in parallel with two standard activators for which the X-ray structure (in complex with isozyme II) has been resolved: histamine and phenylalanine. All three SSRI activated both isozymes with potencies comparable to that of the standards although the profile was different: for hCA I, best activators were fluoxetine and histamine, with citalopram and sertraline showing weaker activity. For hCA II, the best activators were phenylalanine and citalopram, and the weakest histamine and sertraline, whereas fluoxetine showed an intermediate behavior. These results suggest that SSRI efficacy in major depression complicating Alzheimer's disease may be partly due to their ability to activate CA isozymes and may lead to the development of potent activators for the therapy of diseases associated with significant decreases in brain CA activity.

  20. 1H, 13C and 15N resonance assignments and secondary structure analysis of CmPI-II, a serine protease inhibitor isolated from marine snail Cenchritis muricatus.

    PubMed

    Cabrera-Muñoz, Aymara; Rojas, Laritza; Alonso-del-Rivero Antigua, Maday; Pires, José Ricardo

    2016-04-01

    A protease inhibitor (CmPI-II) (UNIPROT: IPK2_CENMR) from the marine mollusc Cenchritis muricatus, has been isolated and characterized. It is the first member of a new group (group 3) of non-classical Kazal-type inhibitors. CmPI-II is a tight-binding inhibitor of serine proteases: trypsin, human neutrophil elastase (HNE), subtilisin A and pancreatic elastase. This specificity is exceptional in the members of Kazal-type inhibitor family. Several models of three-dimensional structure of CmPI-II have been constructed by homology with other inhibitors of the family but its structure has not yet been solved experimentally. Here we report the (1)H, (15)N and (13)C chemical shift assignments of CmPI-II as basis for NMR structure determination and interaction studies. Secondary structure analyses deduced from the NMR chemical shift data have identified three β-strands β1: residues 14-19, β2: 23-35 and β3: 43-45 and one helix α1: 28-37 arranged in the sequential order β1-β2-α1-β3. These secondary structure elements suggest that CmPI-II adopts the typical scaffold of a Kazal-type inhibitor.

  1. Effect of preservation solutions UW and EC on the expression of matrix metalloproteinase II and tissue inhibitor of metalloproteinase II genes in rat kidney.

    PubMed

    Sulikowski, Tadeusz; Domanski, Leszek; Zietek, Zbigniew; Adler, Grażyna; Pawlik, Andrzej; Ciechanowicz, Andrzej; Ciechanowski, Kazimierz; Ostrowski, Marek

    2012-01-30

    Matrix metalloproteinases and tissue inhibitor of metalloproteinases play an important role in the regulation of mesangial cell proliferation and may be involved in ischemia-reperfusion injuries. Preservation solutions are thought to diminish the ischemic injury and appropriate choice of the solution should guarantee a better graft function and good prognosis for graft survival. The aim of the study was to examine the effect of preservation solutions UW and EC on the expression of matrix metalloproteinase II and tissue inhibitor of metalloproteinase II genes in rat kidney. The study was carried out on Wistar rat kidneys divided into 3 groups: kidneys perfused with 0.9% NaCl (control group), with UW, and with EC preservation solution. The results show an enhancement of MMP-2 and TIMP-2 gene expression after 12 min of cold ischemia. This increase was more expressed in kidneys preserved with UW solution in comparison with kidneys perfused with EC solution and 0.9% NaCl. After 24 h of cold ischemia the expression of MMP-2 and TIMP-2 genes in kidney perfused with UW solution decreased, while in kidneys perfused with EC it was increased. After warm ischemia the MMP-2 and TIMP-2 gene expression increased, whereas it was significantly lower in kidneys perfused with EC solution.

  2. Discovery and structure-activity relationships of a novel isothiazolone class of bacterial type II topoisomerase inhibitors.

    PubMed

    Cooper, Ian R; McCarroll, Andrew J; McGarry, David; Kirkham, James; Pichowicz, Mark; Walker, Rolf; Warrilow, Catherine; Salisbury, Anne-Marie; Savage, Victoria J; Moyo, Emmanuel; Forward, Henry; Cheung, Jonathan; Metzger, Richard; Gault, Zoe; Nelson, Gary; Hughes, Diarmaid; Cao, Sha; Maclean, John; Charrier, Cédric; Craighead, Mark; Best, Stuart; Stokes, Neil R; Ratcliffe, Andrew J

    2016-09-01

    There is an urgent and unmet medical need for new antibacterial drugs that tackle infections caused by multidrug-resistant (MDR) pathogens. During the course of our wider efforts to discover and exploit novel mechanism of action antibacterials, we have identified a novel series of isothiazolone based inhibitors of bacterial type II topoisomerase. Compounds from the class displayed excellent activity against both Gram-positive and Gram-negative bacteria with encouraging activity against a panel of MDR clinical Escherichia coli isolates when compared to ciprofloxacin. Representative compounds also displayed a promising in vitro safety profile.

  3. Using DFT methodology for more reliable predictive models: Design of inhibitors of Golgi α-Mannosidase II.

    PubMed

    Bobovská, Adela; Tvaroška, Igor; Kóňa, Juraj

    2016-05-01

    Human Golgi α-mannosidase II (GMII), a zinc ion co-factor dependent glycoside hydrolase (E.C.3.2.1.114), is a pharmaceutical target for the design of inhibitors with anti-cancer activity. The discovery of an effective inhibitor is complicated by the fact that all known potent inhibitors of GMII are involved in unwanted co-inhibition with lysosomal α-mannosidase (LMan, E.C.3.2.1.24), a relative to GMII. Routine empirical QSAR models for both GMII and LMan did not work with a required accuracy. Therefore, we have developed a fast computational protocol to build predictive models combining interaction energy descriptors from an empirical docking scoring function (Glide-Schrödinger), Linear Interaction Energy (LIE) method, and quantum mechanical density functional theory (QM-DFT) calculations. The QSAR models were built and validated with a library of structurally diverse GMII and LMan inhibitors and non-active compounds. A critical role of QM-DFT descriptors for the more accurate prediction abilities of the models is demonstrated. The predictive ability of the models was significantly improved when going from the empirical docking scoring function to mixed empirical-QM-DFT QSAR models (Q(2)=0.78-0.86 when cross-validation procedures were carried out; and R(2)=0.81-0.83 for a testing set). The average error for the predicted ΔGbind decreased to 0.8-1.1kcalmol(-1). Also, 76-80% of non-active compounds were successfully filtered out from GMII and LMan inhibitors. The QSAR models with the fragmented QM-DFT descriptors may find a useful application in structure-based drug design where pure empirical and force field methods reached their limits and where quantum mechanics effects are critical for ligand-receptor interactions. The optimized models will apply in lead optimization processes for GMII drug developments.

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

    SciTech Connect

    Dias, Marcio V.B.; Snee, William C.; Bromfield, Karen M.; Payne, Richard J.; Palaninathan, Satheesh K.; Ciulli, Alessio; Howard, Nigel I.; Abell, Chris; Sacchettini, James C.; Blundell, Tom L.

    2011-09-06

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

  5. Synthesis and biological evaluation of cyclic imides incorporating benzenesulfonamide moieties as carbonic anhydrase I, II, IV and IX inhibitors.

    PubMed

    Abdel-Aziz, Alaa A-M; Angeli, Andrea; El-Azab, Adel S; Abu El-Enin, Mohamed A; Supuran, Claudiu T

    2017-03-01

    A group of cyclic imides was synthesized by reaction of amino-substituted benzenesulfonamides with a series of acid anhydrides such as succinic, maleic, tetrahydrophthalic, pyrazine-2,3-dicarboxylic acid anhydride, and substituted phthalic anhydrides. The synthesized sulfonamides were evaluated as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors against the human (h) isoforms hCA I, II, IV and IX, involved in a variety of diseases among which glaucoma, retinitis pigmentosa, etc. Some of these sulfonamides showed effective inhibitory action (in the nanomolar range) against the cytosolic isoform hCA II and the transmembrane, tumor-associated one hCA IX, making them interesting candidates for preclinical evaluation in glaucoma or various tumors in which the two enzymes are involved. hCA I and IV were on the other hand less inhibited by these sulfonamides, with inhibition constants in the micromolar range.

  6. Kinetic and in silico studies of hydroxy-based inhibitors of carbonic anhydrase isoforms I and II.

    PubMed

    Ekhteiari Salmas, Ramin; Mestanoglu, Mert; Durdagi, Serdar; Sentürk, Murat; Kaya, A Afşin; Kaya, Elif Çelenk

    2016-01-01

    A series of hydroxy and phenolic compounds have been assayed for the inhibition of two physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isozymes, the cytosolic human isozymes I and II. The investigated molecules showed inhibition constants in the range of 1.07-4003 and 0.09-31.5 μM at the hCA I and hCA II enzymes, respectively. In order to investigate the binding mechanisms of these inhibitors, in silico studies were also applied. Molecular docking scores of the studied compounds are compared using three different scoring algorithms, namely Glide/SP, Glide/XP and Glide/IFD. In addition, different ADME (absorption, distribution, metabolism and excretion) analysis was performed. All the examined compounds were found within the acceptable range of pharmacokinetic profiles.

  7. Angiotensin converting enzyme inhibitors and angiotensin II receptor antagonist attenuate tumor growth via polarization of neutrophils toward an antitumor phenotype

    PubMed Central

    Shrestha, Sanjeeb; Noh, Jae Myoung; Kim, Shin-Yeong; Ham, Hwa-Yong; Kim, Yeon-Ja; Yun, Young-Jin; Kim, Min-Ju; Kwon, Min-Soo; Song, Dong-Keun; Hong, Chang-Won

    2016-01-01

    ABSTRACT Tumor microenvironments polarize neutrophils to protumoral phenotypes. Here, we demonstrate that the angiotensin converting enzyme inhibitors (ACEis) and angiotensin II type 1 receptor (AGTR1) antagonist attenuate tumor growth via polarization of neutrophils toward an antitumoral phenotype. The ACEis or AGTR1 antagonist enhanced hypersegmentation of human neutrophils and increased neutrophil cytotoxicity against tumor cells. This neutrophil hypersegmentation was dependent on the mTOR pathway. In a murine tumor model, ACEis and AGTR1 antagonist attenuated tumor growth and enhanced neutrophil hypersegmentation. ACEis inhibited tumor-induced polarization of neutrophils to a protumoral phenotype. Neutrophil depletion reduced the antitumor effect of ACEi. Together, these data suggest that the modulation of Ang II pathway attenuates tumor growth via polarization of neutrophils to an antitumoral phenotype. PMID:26942086

  8. Millepachine, a potential topoisomerase II inhibitor induces apoptosis via activation of NF-κB pathway in ovarian cancer

    PubMed Central

    Ye, Haoyu; Wang, Taijin; Wang, Xiaoyan; Yang, Jianhong; Wei, Yuquan; Zhu, Jingqiang; Chen, Lijuan

    2016-01-01

    Millepachine (MIL) was a novel chalcone that was separated from Millettia pachycarpa Benth (Leguminosae). We found MIL induced apoptosis through activating NF-κB pathway both in SK-OV-3 and A2780S cells. Western blot showed that MIL increased the levels of IKKα, p-IKKα/β, p-IκBα and NF-κB (p65) proteins, and decreased the expression of IκBα protein. Immunohistochemistry analysis indicated that translocation of NF-κB into the nucleus increased in both ovarian cancer cells. EMSA assay proved MIL enhanced NF-κB DNA-binding activity in the nuclear. That specific NF-κB inhibitors alleviated MIL-induced apoptosis suggested NF-κB activation showed a pro-apoptotic function in SK-OV-3 and A2780S cells. Since NF-κB could be activated by double strand breaks and showed a pro-apoptotic function in the DNA damage response, SCGE assay and western blot revealed that MIL caused DNA strand breaks and significantly increased the level of p-ATM protein and further increased the levels of p-IKKα/β and NF-κB (p65) protein in SK-OV-3 and A2780S cells, while a specific ATM inhibitor could alleviated these effects. Moreover, Topoisomerase II drug screening kit and computer modeling assay were used to prove that MIL induced the production of linear DNA and inhibited the activity of topoisomerase II through binding with Topoisomerase II-Cleaved DNA complex to stabilize the complex. Taken together, our results identified that MIL exhibited anti-tumor activity through inhibiting topoisomerase II activity to induce tumor cells DNA damage, and MIL-activated NF-κB pathway showed a pro-apoptotic function in response to DNA damage. PMID:27447570

  9. Carbonic Anhydrase Inhibitors. Part 461 Inhibition of Carbonic Anhydrase Isozymes I, II and IV With Trifluoromethylsulfonamide Derivatives and Their Zinc(II) and Copper(II) Complexes

    PubMed Central

    Mincione, Giovanna; Scozzafava, Andrea

    1997-01-01

    Reaction of aromatic/heterocyclic sulfonamides containing a free amino group with triflic anhydride afforded compounds possessing trifluoromethanesulfonamido moieties in their molecule. The Zn(II) and Cu(II) complexes of these new sulfonamides were prepared and characterized by standard procedures (elemental analysis, spectroscopic, magnetic, thermogravimetric and conductimetric measurements). The new derivatives showed good inhibitory activity against three isozymes of carbonic anhydrase (CA), i.e., CA I, II and IV. PMID:18475762

  10. SYBR Green II Dye-Based Real-Time Assay for Measuring Inhibitor Activity Against HIV-1 Reverse Transcriptase.

    PubMed

    Kokkula, Chakradhar; Palanisamy, Navaneethan; Ericstam, Malin; Lennerstrand, Johan

    2016-10-01

    There are arrays of in vitro assays to quantify the activity of HIV-1 reverse transcriptase (HIV-1 RT). These assays utilize either chemically customized/labelled nucleotides, or TaqMan probes, or radiolabeled nucleotides/primers. Although several real-time PCR assays exist commercially for measuring the RT activity, which are usually used for quantifying the viral titres, these assays are not optimized for measuring the inhibitory concentrations (IC50) of HIV-1 RT inhibitors. Moreover, a recently established inorganic pyrophosphate-coupled enzyme assay cannot be employed for studying nonphosphorylated nucleoside reverse transcriptase inhibitors (NRTIs). In the present study, we have developed a novel one-step assay with native nucleotide substrates and SYBR Green II dye to determine IC50 values of triphosphorylated NRTIs against HIV-1 RT. Using exact batches of wild-type and mutant RT, and triphosphorylated NRTIs, we showed that our method gave IC50 values for inhibitors similar to that of an earlier published colorimetric assay with BrdUTP substrate (CABS). Our assay should be suitable for high-throughput screening of antiretroviral drugs and could also be suitable for studying drug resistance profiles. Additionally, we also used our assay to study inhibition by AZT in its nonphosphorylated form by supplementing the reaction mixture with necessary kinases and ATP.

  11. Novel, potent, selective, and orally bioavailable human betaII-tryptase inhibitors.

    PubMed

    Sperandio, David; Tai, Vincent W-F; Lohman, Julia; Hirschbein, Bernie; Mendonca, Rohan; Lee, Chang-Sun; Spencer, Jeffrey R; Janc, James; Nguyen, Margaret; Beltman, Jerlyn; Sprengeler, Paul; Scheerens, Heleen; Lin, Tong; Liu, Liang; Gadre, Ashwini; Kellogg, Alisha; Green, Michael J; McGrath, Mary E

    2006-08-01

    The synthesis of novel [1,2,4]oxadiazoles and their structure-activity relationship (SAR) for the inhibition of tryptase and related serine proteases is presented. Elaboration of the P'-side afforded potent, selective, and orally bioavailable tryptase inhibitors.

  12. Screening of novel chemical compounds as possible inhibitors of carbonic anhydrase and photosynthetic activity of photosystem II.

    PubMed

    Karacan, Mehmet Sayım; Zharmukhamedov, Sergei K; Mamaş, Serhat; Kupriyanova, Elena V; Shitov, Alexandr V; Klimov, Vyacheslav V; Özbek, Neslihan; Özmen, Ümmühan; Gündüzalp, Ayla; Schmitt, Franz-Josef; Karacan, Nurcan; Friedrich, Thomas; Los, Dmitry A; Carpentier, Robert; Allakhverdiev, Suleyman I

    2014-08-01

    Thirty novel chemical compounds were designed and synthesized expecting that they would be possible inhibitors. From this number eleven were organic bases, twenty-four were their organic derivatives and fourteen were metal complexes. Screening of these chemicals by their action on photosynthetic electron transfer (PET) and carbonic anhydrase (CA) activity (CAA) of photosystem II (PSII), α-CA, as well as β-CA was done. Several groups were revealed among them. Some of them are capable to suppress either one, two, three, or even all of the measured activities. As example, one of the Cu(II)-phenyl sulfonylhydrazone complexes (compound 25) suppresses CAA of α-CA by 88%, CAA of β-CA by 100% inhibition; CAA of PSII by 100% and the PSII photosynthetic activity by 66.2%. The Schiff base compounds (12, 15) and Cu(II)-phenyl sulfonylhydrazone complexes (25, 26) inhibited the CAA and PET of PSII significantly. The obtained data indicate that the PSII donor side is a target of the inhibitory action of these agents. Some physico- or electrochemical properties such as diffusion coefficient, number of transferred electrons, peak potential and heterogeneous standard rate constants of the compounds were determined in nonaqueous media. pKa values were also determined in nonaqueous and aqueous media. Availability in the studied group of novel chemical agents possessing different inhibitory activity allow in future to isolate the "active part" in the structure of the inhibitors responsible for different inhibitory mechanisms, as well as to determine the influence of side substituters on its inhibitory efficiency.

  13. Metalloprotein-inhibitor binding: Human carbonic anhydrase II as a model for probing metal-ligand interactions in a metalloprotein active site

    PubMed Central

    Martin, David P.; Hann, Zachary S.; Cohen, Seth M.

    2013-01-01

    An ever increasing number of metalloproteins are being discovered that play essential roles in physiological processes. Inhibitors of these proteins have significant potential for the treatment of human disease, but clinical success of these compounds has been limited. Herein, Zn(II)-dependent metalloprotein inhibitors in clinical use are reviewed, and the potential for using novel metal-binding groups (MBGs) in the design of these inhibitors is discussed. By using human carbonic anhydrase II (hCAII) as a model system, the nuances of MBG-metal interactions in the context of a protein environment can be probed. Understanding how metal coordination influences inhibitor binding may help in the design new therapeutics targeting metalloproteins. PMID:23706138

  14. A cyclic peptide inhibitor of apoC-II peptide fibril formation: mechanistic insight from NMR and molecular dynamics analysis.

    PubMed

    Griffin, Michael D W; Yeung, Levi; Hung, Andrew; Todorova, Nevena; Mok, Yee-Foong; Karas, John A; Gooley, Paul R; Yarovsky, Irene; Howlett, Geoffrey J

    2012-03-09

    The misfolding and aggregation of proteins to form amyloid fibrils is a characteristic feature of several common age-related diseases. Agents that directly inhibit formation of amyloid fibrils represent one approach to combating these diseases. We have investigated the potential of a cyclic peptide to inhibit fibril formation by fibrillogenic peptides from human apolipoprotein C-II (apoC-II). Cyc[60-70] was formed by disulfide cross-linking of cysteine residues added to the termini of the fibrillogenic peptide comprising apoC-II residues 60-70. This cyclic peptide did not self-associate into fibrils. However, substoichiometric concentrations of cyc[60-70] significantly delayed fibril formation by the fibrillogenic, linear peptides apoC-II[60-70] and apoC-II[56-76]. Reduction of the disulfide bond or scrambling the amino acid sequence within cyc[60-70] significantly impaired its inhibitory activity. The solution structure of cyc[60-70] was solved using NMR spectroscopy, revealing a well-defined structure comprising a hydrophilic face and a more hydrophobic face containing the Met60, Tyr63, Ile66 and Phe67 side chains. Molecular dynamics (MD) studies identified a flexible central region within cyc[60-70], while MD simulations of "scrambled" cyc[60-70] indicated an increased formation of intramolecular hydrogen bonds and a reduction in the overall flexibility of the peptide. Our structural studies suggest that the inhibitory activity of cyc[60-70] is mediated by an elongated structure with inherent flexibility and distinct hydrophobic and hydrophilic faces, enabling cyc[60-70] to interact transiently with fibrillogenic peptides and inhibit fibril assembly. These results suggest that cyclic peptides based on amyloidogenic core peptides could be useful as specific inhibitors of amyloid fibril formation.

  15. Synthesis and discovery of (I-3,II-3)-biacacetin as a novel non-zinc binding inhibitor of MMP-2 and MMP-9.

    PubMed

    Nanjan, Pandurangan; Nambiar, Jyotsna; Nair, Bipin G; Banerji, Asoke

    2015-07-01

    Eleven biflavones (7a-b and 9a-i) were synthesised by a simple and efficient protocol and screened for MMP-2 and MMP-9 inhibitory activities. Amongst them, a natural product-like analog, (I-3,II-3)-biacacetin (9h) was found to be the most potent inhibitor. Molecular docking studies suggest that unlike most of the known inhibitors, 9h inhibits MMP-2 and MMP-9 through non-zinc binding interactions.

  16. Inhibitory effects of KN-93, an inhibitor of Ca2+ calmodulin-dependent protein kinase II, on light-regulated root gravitropism in maize.

    PubMed

    Lu Y-T; Feldman, L J; Hidaka, H

    1993-01-01

    Light is essential for root gravitropism in Zea mays L., cultivar Merit. It is hypothesized that calcium mediates this light-regulated response. KN-93, an inhibitor of calcium/calmodulin kinase II (CaMK II), inhibits light-regulated root gravitropism but does not affect light perception. We hypothesize that CaMK II, or a homologue, operates late in the light/gravity signal transduction chain. Here we provide evidence suggesting a possible physiological involvement of CaMK II in root gravitropism in plants.

  17. Inhibitory effects of KN-93, an inhibitor of Ca2+ calmodulin-dependent protein kinase II, on light-regulated root gravitropism in maize

    NASA Technical Reports Server (NTRS)

    Feldman, L. J.; Hidaka, H.

    1993-01-01

    Light is essential for root gravitropism in Zea mays L., cultivar Merit. It is hypothesized that calcium mediates this light-regulated response. KN-93, an inhibitor of calcium/calmodulin kinase II (CaMK II), inhibits light-regulated root gravitropism but does not affect light perception. We hypothesize that CaMK II, or a homologue, operates late in the light/gravity signal transduction chain. Here we provide evidence suggesting a possible physiological involvement of CaMK II in root gravitropism in plants.

  18. Discovery of novel type II c-Met inhibitors based on BMS-777607.

    PubMed

    Zhang, Wei; Ai, Jing; Shi, Dakuo; Peng, Xia; Ji, Yinchun; Liu, Jian; Geng, Meiyu; Li, Yingxia

    2014-06-10

    Twenty-two new analogs based on the structure of BMS-777607 were designed, synthesized, and evaluated to determine their biological activities. Compounds bearing a cyclic sulfonamide or α-chloropiperidone scaffold exhibited good activity, which may provide a new basis for further structural optimization. Quinoline-containing analogs exhibited better results than did their counterparts with an aminopyrimidine, aminopyridine, or pyrrolopyridine unit. Two analogs, 22d and 22e, stood out as the most potent c-Met inhibitors with IC50s of 0.9 and 1.7 nM, respectively. These two compounds were more potent than BMS-777607 in enzymatic inhibition and cell proliferation studies.

  19. Perioperative management of patients treated with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers: a quality improvement audit.

    PubMed

    Vijay, A; Grover, A; Coulson, T G; Myles, P S

    2016-05-01

    Previous studies have shown that patients continuing angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers on the day of surgery are more likely to have significant intraoperative hypotension, higher rates of postoperative acute kidney injury, and lower incidences of postoperative atrial fibrillation. However, many of these studies were prone to bias and confounding, and questions remain over the validity of these outcomes. This observational, before-and-after quality improvement audit aimed to assess the effect of withholding these medications on the morning of surgery. We recruited 323 participants, with 83 (26%) having their preoperative angiotensin-converting enzyme inhibitor (ACEi) or angiotensin II receptor blocker (ARB) withheld on the day of surgery. There were only very small Spearman rank-order correlations between time since last dose of these medications (rho -0.12, P=0.057) and intraoperative and recovery room intravenous fluid administration (rho -0.11, P=0.042). There was no statistically significant difference between the continued or withheld groups in vasopressor (metaraminol use 3.5 [1.5-8.3] mg versus 3.5 [1.5-8.5] mg, P=0.67) or intravenous fluid administration (1000 ml [800-1500] ml versus 1000 [800-1500] ml, P=0.096), nor rates of postoperative acute kidney injury (13% vs 18%, P=0.25) or atrial fibrillation (15% versus 18%, P=0.71). This audit found no significant differences in measured outcomes between the continued or withheld ACEi/ARB groups. This finding should be interpreted with caution due to the possibility of confounding and an insufficient sample size. However, as the finding is in contrast to many previous studies, future prospective randomised clinical trials are required to answer this important question.

  20. Ruthenium(II) polypyridyl complex as inhibitor of acetylcholinesterase and Aβ aggregation.

    PubMed

    Vyas, Nilima A; Bhat, Satish S; Kumbhar, Avinash S; Sonawane, Uddhavesh B; Jani, Vinod; Joshi, Rajendra R; Ramteke, Shefali N; Kulkarni, Prasad P; Joshi, Bimba

    2014-03-21

    Two ruthenium(II) polypyridyl complexes [Ru(phen)3](2+) (1) and [Ru(phen)2(bxbg)](2+) (2) (where phen = 1,10 phenanthroline, bxbg = bis(o-xylene)bipyridine glycoluril) have been evaluated for acetylcholinesterase (AChE) and Amyloid-β peptide (Aβ) aggregation inhibition. Complex 2 exhibits higher potency of AChE inhibition and kinetics and molecular modeling studies indicate that ancillary ligand plays significant role in inhibitory potency exhibited by complex 2. The inhibitory effect of these complexes on Aβ (1-40) aggregation is investigated using Thioflavin T fluorescence and Transmission Electron Microscopy. Both complexes efficiently inhibit Aβ (1-40) aggregation and are negligibly toxic to human neuroblastoma cells. This is the first demonstration that ruthenium(II) polypyridyl complexes simultaneously inhibit AChE and Aβ aggregation.

  1. Synthesis and biological evaluation of naphthoquinone-coumarin conjugates as topoisomerase II inhibitors.

    PubMed

    Hueso-Falcón, Idaira; Amesty, Ángel; Anaissi-Afonso, Laura; Lorenzo-Castrillejo, Isabel; Machín, Félix; Estévez-Braun, Ana

    2017-02-01

    Based on previous Topoisomerase II docking studies of naphthoquinone derivatives, a series of naphthoquinone-coumarin conjugates was synthesized through a multicomponent reaction from aromatic aldehydes, 4-hydroxycoumarin and 2-hydroxynaphthoquinone. The hybrid structures were evaluated against the α isoform of human topoisomerase II (hTopoIIα), Escherichia coli DNA Gyrase and E. coli Topoisomerase I. All tested compounds inhibited the hTopoIIα-mediated relaxation of negatively supercoiled circular DNA in the low micromolar range. This inhibition was specific since neither DNA Gyrase nor Topoisomerase I were affected. Cleavage assays pointed out that naphthoquinone-coumarins act by catalytically inhibiting hTopoIIα. ATPase assays and molecular docking studies further pointed out that the mode of action is related to the hTopoIIα ATP-binding site.

  2. HMG-CoA reductase inhibitors decrease angiotensin II-induced vascular fibrosis: role of RhoA/ROCK and MAPK pathways.

    PubMed

    Rupérez, Mónica; Rodrigues-Díez, Raquel; Blanco-Colio, Luis Miguel; Sánchez-López, Elsa; Rodríguez-Vita, Juan; Esteban, Vanesa; Carvajal, Gisselle; Plaza, Juan José; Egido, Jesús; Ruiz-Ortega, Marta

    2007-08-01

    3-Hydroxy-3-methylglutaryl (HMG)-coenzyme A (CoA) reductase inhibitors (statins) present beneficial effects in cardiovascular diseases. Angiotensin II (Ang II) contributes to cardiovascular damage through the production of profibrotic factors, such as connective tissue growth factor (CTGF). Our aim was to investigate whether HMG-CoA reductase inhibitors could modulate Ang II responses, evaluating CTGF expression and the mechanisms underlying this process. In cultured vascular smooth muscle cells (VSMCs) atorvastatin and simvastatin inhibited Ang II-induced CTGF production. The inhibitory effect of statins on CTGF upregulation was reversed by mevalonate and geranylgeranylpyrophosphate, suggesting that RhoA inhibition could be involved in this process. In VSMCs, statins inhibited Ang II-induced Rho membrane localization and activation. In these cells Ang II regulated CTGF via RhoA/Rho kinase activation, as shown by inhibition of Rho with C3 exoenzyme, RhoA dominant-negative overexpression, and Rho kinase inhibition. Furthermore, activation of p38MAPK and JNK, and redox process were also involved in Ang II-mediated CTGF upregulation, and were downregulated by statins. In rats infused with Ang II (100 ng/kg per minute) for 2 weeks, treatment with atorvastatin (5 mg/kg per day) diminished aortic CTGF and Rho activation without blood pressure modification. Rho kinase inhibition decreased CTGF upregulation in rat aorta, mimicking statin effect. CTGF is a vascular fibrosis mediator. Statins diminished extracellular matrix (ECM) overexpression caused by Ang II in vivo and in vitro. In summary, HMG-CoA reductase inhibitors inhibit several intracellular signaling systems activated by Ang II (RhoA/Rho kinase and MAPK pathways and redox process) involved in the regulation of CTGF. Our results may explain, at least in part, some beneficial effects of statins in cardiovascular diseases.

  3. 2-Octadecynoic acid as a dual life stage inhibitor of Plasmodium infections and plasmodial FAS-II enzymes.

    PubMed

    Carballeira, Néstor M; Bwalya, Angela Gono; Itoe, Maurice Ayamba; Andricopulo, Adriano D; Cordero-Maldonado, María Lorena; Kaiser, Marcel; Mota, Maria M; Crawford, Alexander D; Guido, Rafael V C; Tasdemir, Deniz

    2014-09-01

    The malaria parasite Plasmodium goes through two life stages in the human host, a non-symptomatic liver stage (LS) followed by a blood stage with all clinical manifestation of the disease. In this study, we investigated a series of 2-alkynoic fatty acids (2-AFAs) with chain lengths between 14 and 18 carbon atoms for dual in vitro activity against both life stages. 2-Octadecynoic acid (2-ODA) was identified as the best inhibitor of Plasmodium berghei parasites with ten times higher potency (IC50=0.34 μg/ml) than the control drug. In target determination studies, the same compound inhibited three Plasmodium falciparum FAS-II (PfFAS-II) elongation enzymes PfFabI, PfFabZ, and PfFabG with the lowest IC50 values (0.28-0.80 μg/ml, respectively). Molecular modeling studies provided insights into the molecular aspects underlying the inhibitory activity of this series of 2-AFAs and a likely explanation for the considerably different inhibition potentials. Blood stages of P. falciparum followed a similar trend where 2-ODA emerged as the most active compound, with 20 times less potency. The general toxicity and hepatotoxicity of 2-AFAs were evaluated by in vitro and in vivo methods in mammalian cell lines and zebrafish models, respectively. This study identifies 2-ODA as the most promising antiparasitic 2-AFA, particularly towards P. berghei parasites.

  4. Unlike other chemicals, etoposide (a topoisomerase-II inhibitor) produces peak mutagenicity in primary spermatocytes of the mouse.

    PubMed

    Russell, L B; Hunsicker, P R; Johnson, D K; Shelby, M D

    1998-05-25

    The cancer chemotherapy agent, and topoisomerase-II inhibitor, etoposide (VP-16) produced both recessive mutations at specific loci and dominants at other loci with peak frequencies in primary spermatocytes, a cell type in which the topo-II gene has been shown to be activated. Etoposide thus differs from all other chemicals whose germ-cell-stage specificity has been analyzed. No effects of etoposide exposure of spermatogonial stem cells ( approximately 15, 000 offspring scored) were detectable by either mutagenicity or productivity endpoints. The significant mutagenic response that followed exposure of poststem-cell stages ( approximately 25,000 offspring scored) showed a clear peak, with three of four specific-locus mutants, and three of four dominant mutants conceived during weeks 4 or 5 (days 22-35) post-injection, a period that also encompassed the dominant-lethal peak. For this period, the induced specific-locus rate (with 95% confidence limits) at a weighted-average exposure of 75.1 mg etop/kg was 59.5 (14.6, 170. 9)x10-6/locus. At least 3 of the 4 specific-locus mutations were deletions, paralleling findings with etoposide or analogs in other test systems where a recombinational origin of the deletions has been suggested. Because, unlike other chemicals that induce deletions in male germ cells, etoposide is effective in stages normally associated with recombinational events, it will be of interest to determine whether this chemical can affect meiotic recombination.

  5. Rho-kinase inhibitor reduces hypersensitivity to ANG II in human mesenteric arteries retrieved and conserved under the same conditions as transplanted organs.

    PubMed

    Szadujkis-Szadurski, Rafal; Slupski, Maciej; Szadujkis-Szadurska, Katarzyna; Szadujkis-Szadurski, Leszek; Jasinski, Milosz; Grzesk, Grzegorz; Grzesk, Elżbieta; Woderska, Aleksandra; Wlodarczyk, Zbigniew

    2014-08-22

    Rho-kinase and GTP-ase Rho are important regulators of vascular tone and blood pressure. The aim of this study was to investigate the role of Rho-kinase in artery reactions induced by angiotensin II (ANG II) and the effects of ischemia-reperfusion injury as well as the function of intra- and extracellular calcium in these reactions. Experiments were performed on mesenteric superior arteries procured from cadaveric organ donors and conserved under the same conditions as transplanted kidneys. The vascular contraction in reaction to ANG II was measured in the presence of Rho-kinase inhibitor Y-27632, after ischemia and reperfusion, in Ca2+ and Ca2+-free solution. The maximal response to ANG II was reduced after ischemia, while an increase was observed after reperfusion. Vascular contraction induced by ANG II was decreased by Y-27632. Y-27632 reduced vascular contraction after reperfusion, both in Ca2+ and Ca2+-free solution. Reperfusion augments vascular contraction in reaction to ANG II. The Rho-kinase inhibitor Y-27632 reduces the hypersensitivity to ANG II after reperfusion mediated by both intra- and extracellular calcium. These results confirm the role of Rho-kinase in receptor-independent function of ANG II and in reperfusion-induced hypersensitivity.

  6. Small molecule inhibitors of peptidoglycan synthesis targeting the lipid II precursor.

    PubMed

    Derouaux, Adeline; Turk, Samo; Olrichs, Nick K; Gobec, Stanislav; Breukink, Eefjan; Amoroso, Ana; Offant, Julien; Bostock, Julieanne; Mariner, Katherine; Chopra, Ian; Vernet, Thierry; Zervosen, Astrid; Joris, Bernard; Frère, Jean-Marie; Nguyen-Distèche, Martine; Terrak, Mohammed

    2011-05-01

    Bacterial peptidoglycan glycosyltransferases (GTs) of family 51 catalyze the polymerization of the lipid II precursor into linear peptidoglycan strands. This activity is essential to bacteria and represents a validated target for the development of new antibacterials. Application of structure-based virtual screening to the National Cancer Institute library using eHits program and the structure of the glycosyltransferase domain of the Staphylococcus aureus penicillin-binding protein 2 resulted in the identification of two small molecules analogues 5, a 2-[1-[(2-chlorophenyl)methyl]-2-methyl-5-methylsulfanylindol-3-yl]ethanamine and 5b, a 2-[1-[(3,4-dichlorophenyl)methyl]-2-methyl-5-methylsulfanylindol-3-yl]ethanamine that exhibit antibacterial activity against several Gram-positive bacteria but were less active on Gram-negative bacteria. The two compounds inhibit the activity of five GTs in the micromolar range. Investigation of the mechanism of action shows that the compounds specifically target peptidoglycan synthesis. Unexpectedly, despite the fact that the compounds were predicted to bind to the GT active site, compound 5b was found to interact with the lipid II substrate via the pyrophosphate motif. In addition, this compound showed a negatively charged phospholipid-dependent membrane depolarization and disruption activity. These small molecules are promising leads for the development of more active and specific compounds to target the essential GT step in cell wall synthesis.

  7. [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.

  8. Polyamine metabolism and osmotic stress. II. Improvement of oat protoplasts by an inhibitor of arginine decarboxylase

    NASA Technical Reports Server (NTRS)

    Tiburcio, A. F.; Kaur-Sawhney, R.; Galston, A. W.

    1986-01-01

    We have attempted to improve the viability of cereal mesophyll protoplasts by pretreatment of leaves with DL-alpha-difluoromethylarginine (DFMA), a specific 'suicide' inhibitor of the enzyme (arginine decarboxylase) responsible for their osmotically induced putrescine accumulation. Leaf pretreatment with DFMA before a 6 hour osmotic shock caused a 45% decrease of putrescine and a 2-fold increase of spermine titer. After 136 hours of osmotic stress, putrescine titer in DFMA-pretreated leaves increased by only 50%, but spermidine and spermine titers increased dramatically by 3.2- and 6-fold, respectively. These increases in higher polyamines could account for the reduced chlorophyll loss and enhanced ability of pretreated leaves to incorporate tritiated thymidine, uridine, and leucine into macromolecules. Pretreatment with DFMA significantly improved the overall viability of the protoplasts isolated from these leaves. The results support the view that the osmotically induced rise in putrescine and blockage of its conversion to higher polyamines may contribute to the lack of sustained cell division in cereal mesophyll protoplasts, although other undefined factors must also play a major role.

  9. Plasminogen activator inhibitor-1 gene-deficient mice. II. Effects on hemostasis, thrombosis, and thrombolysis.

    PubMed Central

    Carmeliet, P; Stassen, J M; Schoonjans, L; Ream, B; van den Oord, J J; De Mol, M; Mulligan, R C; Collen, D

    1993-01-01

    The effects of plasminogen activator inhibitor-1 (PAI-1) gene inactivation on hemostasis, thrombosis and thrombolysis were studied in homozygous PAI-1-deficient (PAI-1-/-) mice, generated by homologous recombination in D3 embryonic stem cells. Diluted (10-fold) whole blood clots from PAI-1-/- and from PAI-1 wild type (PAI-1+/+) mice underwent limited but significantly different (P < 0.001) spontaneous lysis within 3 h (6 +/- 1 vs 3 +/- 1%, respectively). A 25-microliters 125I-fibrin-labeled normal murine plasma clot, injected into a jugular vein, was lysed for 47 +/- 5, 66 +/- 3, and 87 +/- 7% within 8 h in PAI-1+/+, heterozygous PAI-1-deficient (PAI-1+/-), and PAI-1-/- mice, respectively (P = 0.002 for PAI-1+/+ vs PAI-1-/- mice). Corresponding values after pretreatment with 0.5 mg/kg endotoxin in PAI-1+/+ and PAI-1-/- mice, were 35 +/- 5 and 91 +/- 3% within 4 h, respectively (P < 0.001). 11 out of 26 PAI-1+/+ but only 1 out of 25 PAI-1-/- mice developed venous thrombosis (P = 0.004) within 6 d after injection of 10 or 50 micrograms endotoxin in the footpad. Spontaneous bleeding or delayed rebleeding could not be documented in PAI-1-/- mice after partial amputation of the tail or of the caecum. Thus, disruption of the PAI-1 gene in mice appears to induce a mild hyperfibrinolytic state and a greater resistance to venous thrombosis but not to impair hemostasis. Images PMID:8254029

  10. A biochemical logic gate using an enzyme and its inhibitor. Part II: The logic gate.

    PubMed

    Sivan, Sarit; Tuchman, Samuel; Lotan, Noah

    2003-06-01

    Enzyme-Based Logic Gates (ENLOGs) are key components in bio-molecular systems for information processing. This report and the previous one in this series address the characterization of two bio-molecular switching elements, namely the alpha-chymotrypsin (alphaCT) derivative p-phenylazobenzoyl-alpha-chymotrypsin (PABalphaCT) and its inhibitor (proflavine), as well as their assembly into a logic gate. The experimental output of the proposed system is expressed in terms of enzymic activity and this was translated into logic output (i.e. "1" or "0") relative to a predetermined threshold value. We have found that an univalent link exists between the dominant isomers of PABalphaCT (cis or trans), the dominant form of either acridine (proflavine) or acridan and the logic output of the system. Thus, of all possible combinations, only the trans-PABalphaCT and the acridan lead to an enzymic activity that can be defined as logic output "1". The system operates under the rules of Boolean algebra and performs as an "AND" logic gate.

  11. Natural product inhibitors of carbonic anhydrase I and II isoenzymes: osajin and pomiferin.

    PubMed

    Dilek, Esra; Erol, Hüseyin Serkan; Cakir, Ahmet; Koc, Murat; Halici, Mesut Bünyami

    2017-03-24

    The aim of this study is to purify carbonic anhydrase I and II isoenzymes from human erythrocyte, isolate two natural products osajin (OSJ) and pomiferin (PMF) from Maclura pomifera fruits, and evaluate the in vitro effect of these natural metabolites on these isoenzymes. These natural products may be used as starting points for drug discovery (like drugs used in several therapeutic applications, including antiglaucoma activity). For the purification procedure, the Sepharose-4B-l-tyrosine-sulphonamide affinity chromatography was used. Column chromatography and thin layer chromatography methods were used for isolation of OSJ and PMF from M. pomifera fruits and their chemical structures were elucidated by IR, 1D, and 2D NMR methods. We compared inhibitory effects of these natural products with inhibitory effects of phenolic compounds and found that these products demonstrated average inhibition effects. We thought that this study will give inspiration to scientists interested in this issue.

  12. Characterization and comparative 3D modeling of CmPI-II, a novel 'non-classical' Kazal-type inhibitor from the marine snail Cenchritis muricatus (Mollusca).

    PubMed

    González, Yamile; Pons, Tirso; Gil, Jeovanis; Besada, Vladimir; Alonso-del-Rivero, Maday; Tanaka, Aparecida S; Araujo, Mariana S; Chávez, María A

    2007-11-01

    The complete amino acid sequence obtained by electrospray ionization tandem mass spectrometry of the proteinase inhibitor CmPI-II isolated from Cenchritis muricatus is described. CmPI-II is a 5480-Da protein with three disulfide bridges that inhibits human neutrophil elastase (HNE) (K(i) 2.6+/-0.2 nM), trypsin (K(i) 1.1+/-0.9 nM), and other serine proteinases such as subtilisin A (K(i) 30.8+/-1.2 nM) and pancreatic elastase (K(i) 145.0+/-4.4 nM); chymotrypsin, pancreatic and plasma kallikreins, thrombin and papain are not inhibited. CmPI-II shares homology with the Kazal-type domain and may define a new group of 'non-classical' Kazal inhibitors according to its Cys(I)-Cys(V) disulfide bridge position. The 3D model of CmPI-II exhibits similar secondary structure characteristics to Kazal-type inhibitors and concurs with circular dichroism experiments. A 3D model of the CmPI-II/HNE complex provides a structural framework for the interpretation of its experimentally determined K(i) value. The model shows both similar and different contacts at the primary binding sites in comparison with the structure of turkey ovomucoid third domain (OMTKY3)/HNE used as template. Additional contacts calculated at the protease-inhibitor interface could also contribute to the association energy of the complex. This inhibitor represents an exception in terms of specificity owing to its ability to strongly inhibit elastases and trypsin.

  13. Growth-inhibitory activity of lymphoid cell plasma membranes. II. Partial characterization of the inhibitor

    PubMed Central

    1984-01-01

    We have shown that plasma membranes from lymphoid cells have inhibitory activity for the growth of normal lymphocytes and lymphoid tumor cells (Stallcup, K. C., A. Dawson, and M. F. Mescher, J. Cell Biol. 99:1221- 1226). This growth-inhibitory activity has been found to co-purify with major histocompatibility complex class I antigens (H-2K and D) when these cell surface glycoproteins are isolated from detergent lysates of cells by affinity chromatography on monoclonal antibody columns. When incorporated into liposomes, the affinity-purified H-2 antigens inhibited the growth of both normal lymphocytes and tumor cells at concentrations of 1-3 micrograms/ml. Inhibition was readily reversed upon removal of the liposomes from the cell cultures, even after several days of exposure of cells to the inhibitor. Inhibitory activity was insensitive to protease digestion or heat treatment, indicating that it was not due to the H-2 glycoproteins. This was confirmed by the demonstration that inhibitory activity could be separated from the H-2 protein by gel filtration in the presence of deoxycholate and could be extracted from membranes or H-2 antigen preparations with organic solvents. The results demonstrate that the growth-inhibitory component(s) of the plasma membrane is a minor lipid or lipid-like molecule which retains activity in the absence of other membrane components. The findings reported here and in the preceding article suggest that this novel membrane component may have a role in control of lymphoid cell growth, possibly mediated by cell contacts. PMID:6332814

  14. Angiotensin II Receptor Blocker Neprilysin Inhibitor (ARNI): New Avenues in Cardiovascular Therapy.

    PubMed

    Volpe, M; Tocci, G; Battistoni, A; Rubattu, S

    2015-09-01

    The burden of cardiovascular disease (CVD) is continuously and progressively raising worldwide. Essential hypertension is a major driver of cardiovascular events, including coronary artery disease, myocardial infarction, ischemic stroke and congestive heart failure. This latter may represent the final common pathway of different cardiovascular diseases, and it is often mediated by progressive uncontrolled hypertension. Despite solid advantages derived from effective and sustained blood pressure control, and the widespread availability of effective antihypertensive medications, the vast majority of the more than 1 billion hypertensive patients worldwide continue to have uncontrolled hypertension. Among various factors that may be involved, the abnormal activation of neurohormonal systems is one consistent feature throughout the continuum of cardiovascular diseases. These systems may initiate biologically meaningful "injury responses". However, their sustained chronic overactivity often may induce and maintain the progression from hypertension towards congestive heart failure. The renin-angiotensin-aldosteron system, the sympathetic nervous system and the endothelin system are major neurohormonal stressor systems that are not only able to elevate blood pressure levels by retaining water and sodium, but also to play a role in the pathophysiology of cardiovascular diseases. More recently, the angiotensin receptor neprilysin inhibitor (ARNI) represents a favourable approach to inhibit neutral endopeptidase (NEP) and suppress the RAAS via blockade of the AT1 receptors, without the increased risk of angioedema. LCZ696, the first-in-class ARNI, has already demonstrated BP lowering efficacy in patients with hypertension, in particular with respect to systolic blood pressure levels, improved cardiac biomarkers, cardiac remodelling and prognosis in patients with heart failure. This manuscript will briefly overview the main pathophysiological and therapeutic aspects of ARNI in

  15. ACE inhibitors and angiotensin II receptor blockers in IgA nephropathy with mild proteinuria: the ACEARB study.

    PubMed

    Pozzi, Claudio; Del Vecchio, Lucia; Casartelli, Donatella; Pozzoni, Pietro; Andrulli, Simeone; Amore, Alessandro; Peruzzi, Licia; Coppo, Rosanna; Locatelli, Francesco

    2006-01-01

    Few studies have investigated IgA nephropathy patients presenting with 'favorable' clinical features at onset, such as normal renal function, proteinuria<1 g/24 hours and the absence of hypertension, and no controlled clinical trials have tested the effects of treatment in such patients who may nevertheless develop end-stage renal disease. It is therefore important to find a well-tolerated and economic therapy capable of decreasing their risk of high proteinuria and blood pressure levels. The aim of this multicenter open-label randomized clinical trial is to test whether blocking the renin-angiotensin system (RAS) decreases the risk of progression in patients aged 3-60 years with biopsy-proven benign IgA glomerulonephritis, proteinuria levels of 0.3-0.9 g/24 hours, and normal renal function and blood pressure. The RAS is blocked by first using a single drug class (angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker), and then combining the 2 classes as soon as the 1-drug blockade has become ineffective. We plan to enroll 378 patients over the next 3 years and randomize them to receive ramipril 5 mg/day (3 mg/m2 in children) (group A), irbesartan 300 mg/day (175 mg/m 2 in children) (group B) or supportive therapy (group C); if an increase in proteinuria of at least 50% from baseline is detected after 6 months of treatment, the other RAS inhibitor will be added. The observation period will be at least 5 years (except in the case of the development of the primary end point).

  16. Topoisomerase II Inhibitors Induce DNA Damage-Dependent Interferon Responses Circumventing Ebola Virus Immune Evasion

    PubMed Central

    Luthra, Priya; Aguirre, Sebastian; Yen, Benjamin C.; Pietzsch, Colette A.; Sanchez-Aparicio, Maria T.; Tigabu, Bersabeh; Morlock, Lorraine K.; García-Sastre, Adolfo; Leung, Daisy W.; Williams, Noelle S.; Fernandez-Sesma, Ana; Bukreyev, Alexander

    2017-01-01

    ABSTRACT Ebola virus (EBOV) protein VP35 inhibits production of interferon alpha/beta (IFN) by blocking RIG-I-like receptor signaling pathways, thereby promoting virus replication and pathogenesis. A high-throughput screening assay, developed to identify compounds that either inhibit or bypass VP35 IFN-antagonist function, identified five DNA intercalators as reproducible hits from a library of bioactive compounds. Four, including doxorubicin and daunorubicin, are anthracycline antibiotics that inhibit topoisomerase II and are used clinically as chemotherapeutic drugs. These compounds were demonstrated to induce IFN responses in an ATM kinase-dependent manner and to also trigger the DNA-sensing cGAS-STING pathway of IFN induction. These compounds also suppress EBOV replication in vitro and induce IFN in the presence of IFN-antagonist proteins from multiple negative-sense RNA viruses. These findings provide new insights into signaling pathways activated by important chemotherapy drugs and identify a novel therapeutic approach for IFN induction that may be exploited to inhibit RNA virus replication. PMID:28377530

  17. Novel angular benzophenazines: dual topoisomerase I and topoisomerase II inhibitors as potential anticancer agents.

    PubMed

    Vicker, Nigel; Burgess, Luke; Chuckowree, Irina S; Dodd, Rory; Folkes, Adrian J; Hardick, David J; Hancox, Timothy C; Miller, Warren; Milton, John; Sohal, Sukhjit; Wang, Shouming; Wren, Stephen P; Charlton, Peter A; Dangerfield, Wendy; Liddle, Chris; Mistry, Prakash; Stewart, Alistair J; Denny, William A

    2002-01-31

    A series of substituted angular benzophenazines were prepared using a new synthetic route via a novel regiocontrolled condensation of 1,2-naphthoquinones and 2,3-diaminobenzoic acids. The synthesis and biological activity of this new series of substituted 8,9-benzo[a]phenazine carboxamide systems are described. The analogues were evaluated against the H69 parental human small cell lung carcinoma cell line and H69/LX4 resistant cell line which overexpresses P-glycoprotein. Selected analogues were evaluated against the COR-L23 parental human non small cell lung carcinoma cell line and the COR-L23/R resistant cell line which overexpresses multidrug resistance protein. This series of novel angular benzophenazines were potent cytotoxic agents in these cell lines and may be able to circumvent multidrug resistance mechanisms which result in the lack of efficacy of many drugs in cancer chemotherapy. These compounds show dual inhibition of topoisomerase I and topoisomerase II and thus target two key enzymes responsible for the topology of DNA that are active at different points in the cell cycle. The introduction of chirality into the carboxamide side chain of these novel benzophenazine carboxamides has resulted in the discovery of a potent enantiospecific series of cytotoxic agents, exemplified by 4-methoxy-benzo[a]phenazine-11-carboxylic acid (2-(dimethylamino)-1-(R)-methyl-ethyl)-amide, XR11576 ((R)-4j' '). In vivo activity has been demonstrated for 4-methoxy-benzo[a]phenazine-11-carboxylic acid (2-(dimethylamino)-1-(R)-methyl-ethyl)-amide, XR11576, after intravenous administration to female mice, and this compound has been selected as a development candidate for further evaluation.

  18. Conformation and recognition of DNA damaged by antitumor cis-dichlorido platinum(II) complex of CDK inhibitor bohemine.

    PubMed

    Novakova, Olga; Liskova, Barbora; Vystrcilova, Jana; Suchankova, Tereza; Vrana, Oldrich; Starha, Pavel; Travnicek, Zdenek; Brabec, Viktor

    2014-05-06

    A substitution of the ammine ligands of cisplatin, cis-[Pt(NH3)2Cl2], for cyclin dependent kinase (CDK) inhibitor bohemine (boh), [2-(3-hydroxypropylamino)-6-benzylamino-9-isopropylpurine], results in a compound, cis-[Pt(boh)2Cl2] (C1), with the unique anticancer profile which may be associated with some features of the damaged DNA and/or its cellular processing (Travnicek Z et al. (2003) J Inorg Biochem94, 307-316; Liskova B (2012) Chem Res Toxicol25, 500-509). A combination of biochemical and molecular biology techniques was used to establish mechanistic differences between cisplatin and C1 with respect to the DNA damage they produce and their interactions with critical DNA-binding proteins, DNA-processing enzymes and glutathione. The results show that replacement of the NH3 groups in cisplatin by bohemine modulates some aspects of the mechanism of action of C1. More specifically, the results of the present work are consistent with the thesis that, in comparison with cisplatin, effects of other factors, such as: (i) slower rate of initial binding of C1 to DNA; (ii) the lower efficiency of C1 to form bifunctional adducts; (iii) the reduced bend of longitudinal DNA axis induced by the major 1,2-GG intrastrand cross-link of C1; (iv) the reduced affinity of HMG domain proteins to the major adduct of C1; (v) the enhanced efficiency of the DNA adducts of C1 to block DNA polymerization and to inhibit transcription activity of human RNA pol II and RNA transcription; (vi) slower rate of the reaction of C1 with glutathione, may partially contribute to the unique activity of C1.

  19. Spatial and temporal expression patterns of diverse Pin-II proteinase inhibitor genes in Capsicum annuum Linn.

    PubMed

    Tamhane, Vaijayanti A; Giri, Ashok P; Kumar, Pavan; Gupta, Vidya S

    2009-08-01

    Pin-II type proteinase inhibitor (PI) genes were cloned from fruit and stem tissues of Capsicum annuum L. var Phule Jyoti using primers designed from reported CanPI gene sequence (AF039398). In total, 21 novel CanPIs, members of the Pin-II PI family, were identified in the study, with three isoforms of 1-inhibitory repeat domain (IRD), eight isoforms of 2-IRD, three isoforms of 3-IRD, five isoforms of 4-IRD and two partial CanPI sequences. Most of the sequences showed variation (2 to 20%) in the deduced AA sequences which were pronounced close to the reactive site loop. Expression patterns of CanPIs in the fruit and stem tissues of mature C. annuum plants were shown to vary qualitatively and quantitatively using semi-quantitative RT-PCR expression analysis. In the fruit tissue, CanPIs with different IRDs (from 1 to 4) were expressed simultaneously. In stem tissue, 1- and 2-IRD CanPIs were strongly expressed along moderate expression of 3- and 4-IRD genes. Analysis of CanPI protein activity showed a range of active forms across the tissues. CanPI expression was differentially up-regulated upon wounding and insect attack. Although infestation by aphids (Myzus persicae) and lepidopteran pests (Spodoptera litura) specifically induced 4-IRD CanPIs, virus-infected leaves did not affect CanPI expression. Analysis of CanPI protein activity indicated that the up-regulation in CanPI expression was not always correlated with increase in PI activity. Our results demonstrated that CanPI expression is regulated spatially, temporally as well as qualitatively and quantitatively.

  20. An optimized micro-assay of myosin II ATPase activity based on the molybdenum blue method and its application in screening natural product inhibitors.

    PubMed

    Chen, Hong-Lin; Zhao, Jing; Zhang, Guan-Jun; Kou, Jun-Ping; Yu, Bo-Yang

    2016-06-01

    Myosin II plays multiple roles in physiological and pathological functions through its ATPase activity. The present study was designed to optimize a micro-assay of myosin II ATPase activity based on molybdenum blue method, using a known myosin II ATPase inhibitor, blebbistatin. Several parameters were observed in the enzymatic reaction procedure, including the concentrations of the substrate (ATP) and calcium chloride, pH, and the reaction and incubation times. The proportion of coloration agent was also investigated. The sensitivity of this assay was compared with the malachite green method and bioluminescence method. Additionally, 20 natural compounds were studied for myosin II ATPase inhibitory activity using the optimized method. Our results showed that ATP at the concentration of 5 mmol·L(-1) and ammonium molybdate : stannous chloride at the ratio of 15 : 1 could greatly improve the sensitivity of this method. The IC50 of blebbistatin obtained by this method was consistent with literature. Compound 8 was screened with inhibitory activity on myosin II ATPase. The optimized method showed similar accuracy, lower detecting limit, and wider linear range, which could be a promising approach to screening myosin II ATPase inhibitors in vitro.

  1. Circulating T lymphocyte subsets, cytokines, and immune checkpoint inhibitors in patients with bipolar II or major depression: a preliminary study

    PubMed Central

    Wu, Wei; Zheng, Ya-li; Tian, Li-ping; Lai, Jian-bo; Hu, Chan-chan; Zhang, Peng; Chen, Jing-kai; Hu, Jian-bo; Huang, Man-li; Wei, Ning; Xu, Wei-juan; Zhou, Wei-hua; Lu, Shao-jia; Lu, Jing; Qi, Hong-li; Wang, Dan-dan; Zhou, Xiao-yi; Duan, Jin-feng; Xu, Yi; Hu, Shao-hua

    2017-01-01

    This study aimed to investigate the less known activation pattern of T lymphocyte populations and immune checkpoint inhibitors on immunocytes in patients with bipolar II disorder depression (BD) or major depression (MD). A total of 23 patients with BD, 22 patients with MD, and 20 healthy controls (HCs) were recruited. The blood cell count of T lymphocyte subsets and the plasma level of cytokines (IL-2, IL-4, IL-6, IL-10, TNF-α, and IFN-γ) were selectively investigated. The expression of T-cell immunoglobulin and mucin-domain containing-3 (TIM-3), programmed cell death protein 1 (PD-1) and its ligands, PD-L1 and PD-L2, on T lymphocytes and monocytes, was detected. In results, blood proportion of cytotoxic T cells significantly decreased in BD patients than in either MD patients or HCs. The plasma level of IL-6 increased in patients with BD and MD. The expression of TIM-3 on cytotoxic T cells significantly increased, whereas the expression of PD-L2 on monocytes significantly decreased in patients with BD than in HCs. These findings extended our knowledge of the immune dysfunction in patients with affective disorders. PMID:28074937

  2. Growth and development of Colorado potato beetle larvae, Leptinotarsa decemlineata, on potato plants expressing the oryzacystatin II proteinase inhibitor.

    PubMed

    Cingel, Aleksandar; Savić, Jelena; Vinterhalter, Branka; Vinterhalter, Dragan; Kostić, Miroslav; Jovanović, Darka Šešlija; Smigocki, Ann; Ninković, Slavica

    2015-08-01

    Plant proteinase inhibitors (PIs) are attractive tools for crop improvement and their heterologous expression can enhance insect resistance in transgenic plants. PI oryzacystatin II (OCII), isolated from rice, showed potential in controlling pests that utilize cysteine proteinases for protein digestion. To evaluate the applicability of the OCII gene in enhancing plant defence, OCII-transformed potatoes were bioassayed for resistance to Colorado potato beetle (Leptinotarsa decemlineata Say). Feeding on transformed leaves of potato cultivars Desiree and Jelica significantly affected larval growth and development, but did not change mortality rates. During the L2 and L3 developmental stages larvae consumed the OCII-transformed foliage faster as compared to the nontransformed control. Also these larvae reached the prepupal stage (end of L4 stage) 2 days earlier than those fed on control leaves. However, the total amounts of consumed OCII-transformed leaves were up to 23% lower than of control, and the maximal weights of prepupal larvae were reduced by up to 18% as compared to larvae fed on nontransformed leaves. The reduction in insect fitness reported in this study in combination with other control measures, could lead to improved CPB resistance management in potato.

  3. Multi-targeted organometallic ruthenium(II)-arene anticancer complexes bearing inhibitors of poly(ADP-ribose) polymerase-1: A strategy to improve cytotoxicity.

    PubMed

    Wang, Zhigang; Qian, Hui; Yiu, Shek-Man; Sun, Jianwei; Zhu, Guangyu

    2014-02-01

    Small-molecule inhibitors of poly(ADP-ribose) polymerase-1 (PARP-1) have currently drawn much attention as promising chemotherapeutic drug candidates, and there is a need to develop more potent PARP inhibitors with improved bioavailability. Here we report a strategy to improve the cytotoxicity of PARP inhibitors by conjugation with organometallic ruthenium(II)-arene compounds. We also report a systematic study to reveal the mechanism of action of these ruthenium-PARP inhibitor conjugates. The complexes have been synthesized and characterized spectroscopically. The improved antiproliferative activity from the as-prepared complexes in four human cancer cell lines has indicated their potential for further development as antitumor drugs. Cellular uptake study reveals that the most active complex 3 easily entered into cells. Target validation assays show that the complexes inhibited PARP-1 slightly better than the original PARP inhibitors, that complex 3 strongly bound to DNA and inhibited transcription, and that this complex arrested the cell cycle at the G0/G1 stage. This type of information could shed light on the design of the next generation of more active ruthenium-PARP inhibitor conjugates.

  4. Pharmacological properties and pathophysiological significance of a Kunitz-type protease inhibitor (Rusvikunin-II) and its protein complex (Rusvikunin complex) purified from Daboia russelii russelii venom.

    PubMed

    Mukherjee, Ashis K; Mackessy, Stephen P

    2014-10-01

    A 7.1 kDa basic peptide (Rusvikunin-II) was purified from a previously described protein complex (Rusvikunin complex, consists of Rusvikunin and Rusvikunin-II) of Daboia russelii russelii venom. The N-terminal sequence of Rusvikunin-II was found to be blocked, but peptide mass fingerprinting analysis indicated its identity as Kunitz-type basic protease inhibitor 2, previously reported from Russell's Viper venom. A tryptic peptide sequence of Rusvikunin-II containing the N-terminal sequence HDRPTFCNLFPESGR demonstrated significant sequence homology to venom basic protease inhibitors, Kunitz-type protease inhibitors and trypsin inhibitors. The secondary structure of Rusvikunin-II was dominated by β-sheets (60.4%), followed by random coil (38.2%), whereas α-helix (1.4%) contributes the least to its secondary structure. Both Rusvikunin-II and the Rusvikunin complex demonstrated dose-dependent anticoagulant activity; however, the anticoagulant potency of latter was found to be higher. Both inhibited the amidolytic activity of trypsin > plasmin > FXa, fibrinogen clotting activity of thrombin, and, to a lesser extent, the prothrombin activation property of FXa; however, the inhibitory effect of the Rusvikunin complex was more pronounced. Neither Rusvikunin-II nor Rusvikunin complex inhibited the amidolytic activity of chymotrypsin and thrombin. Rusvikunin-II at 10 μg/ml was not cytotoxic to Colo-205, MCF-7 or 3T3 cancer cells; conversely, Rusvikunin complex showed ∼30% reduction of MCF-7 cells under identical experimental conditions. Rusvikunin-II (5.0 mg/kg body weight, i.p. injection) was not lethal to mice or House Geckos; nevertheless, it showed in vivo anticoagulant action in mice. However, the Rusvikunin complex (at 5.0 mg/kg) was toxic to NSA mice, but not to House Geckos, suggesting it has prey-specific toxicity. Rusvikunin complex-treated mice exhibited dyspnea and hind-limb paresis prior to death. The present study indicates that the Kunitz

  5. Pyrrolo[3,2-d]pyrimidine derivatives as type II kinase insert domain receptor (KDR) inhibitors: CoMFA and CoMSIA studies.

    PubMed

    Wu, Xiao-Yun; Chen, Wen-Hua; Wu, Shu-Guang; Tian, Yuan-Xin; Zhang, Jia-Jie

    2012-01-01

    Kinase insert domain receptor (KDR) inhibitors have been proved to be very effective anticancer agents. Molecular docking, 3D-QSAR methods, CoMFA and CoMSIA were performed on pyrrolo[3,2-d]pyrimidine derivatives as non-ATP competitive KDR inhibitors (type II). The bioactive conformation was explored by docking one potent compound 20 into the active site of KDR in its DFG-out inactive conformation. The constructed CoMFA and CoMSIA models produced statistically significant results with the cross-validated correlation coefficients q(2) of 0.542 and 0.552, non-cross-validated correlation coefficients r(2) of 0.912 and 0.955, and predicted correction coefficients r(2) (pred) of 0.913 and 0.897, respectively. These results ensure the CoMFA and CoMSIA models as a tool to guide the design of a series of new potent KDR inhibitors.

  6. Role of salt bridge dynamics in inter domain recognition of human IMPDH isoforms: an insight to inhibitor topology for isoform-II.

    PubMed

    Bairagya, Hridoy R; Mukhopadhyay, Bishnu P; Bera, Asim K

    2011-12-01

    Inosine monophosphate dehydrogenase (IMPDH) enzyme involves in the biosynthesis pathway of guanosine nucleotide. Type II isoform of the enzyme is selectively upregulated in neoplastic fast replicating lymphocytes and CML cancer cells. The hIMPDH-II is an excellent target for antileukemic agent. The detailed investigation during MD-Simulation (15 ns) of three different unliganded structures (1B3O, 1JCN and 1JR1) have clearly explored the salt bridge mediated stabilization of inter or intra domain (catalytic domains I(N), I(C) with res. Id. 28-111 and 233-504, whereas two CBS domains C₁, C₂ are 112-171 and 172-232) in IMPDH enzyme which are mostly inaccessible in their X-rays structures. The salt bridge interaction in I(N)---C₁ inter-domain of hIMPDH-I, I(N)---C₂ of IMPDH-II and C₁---I(C) of nhIMPDH-II are discriminative features among the isoforms. The I(N)---C₂ recognition in hIMPDH-II (1B3O) is missing in type-I isoform (1JCN). The salt bridge interaction D232---K238 at the surface of protein and the involvement of three conserved water molecules or the hydrophilic centers (WA²³²(OD1), WB ²³²(OD2) and W²³⁸(NZ)) to those acidic and basic residues seem to be unique in hIMPDH-II. The hydrophilic susceptibility, geometrical and electronic consequences of this salt bridge interaction could be useful to design the topology of specific inhibitor for hIMPDH-II which may not be effective for hIMPDH-I. Possibly, the aliphatic ligand containing carboxyl, amide or hydrophilic groups with flexible structure may be implicated for hIMPDH-II inhibitor design using the conserved water mimic drug design protocol.

  7. Phase II study of glucosamine with chondroitin on aromatase inhibitor-associated joint symptoms in women with breast cancer

    PubMed Central

    Greenlee, Heather; Crew, Katherine D.; Shao, Theresa; Kranwinkel, Grace; Kalinsky, Kevin; Maurer, Matthew; Brafman, Lois; Insel, Beverly; Tsai, Wei Yann

    2013-01-01

    Purpose Many women with hormone receptor-positive breast cancer discontinue effective aromatase inhibitor (AI) treatment due to joint symptoms. Methods We conducted a single-arm, open-label, phase II study evaluating glucosamine-sulfate (1,500 mg/day)+ chondroitin-sulfate (1,200 mg/day) for 24 weeks to treat joint pain/stiffness in postmenopausal women with early stage breast cancer who developed moderate-to-severe joint pain after initiating AIs. The primary endpoint was improvement in pain/stiffness at week 24 assessed by the Outcome Measure in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) criteria. Secondary endpoints assessed changes in pain, stiffness, and function using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index for hips/knees and the Modified Score for the Assessment and Quantification of Chronic Rheumatoid Affections of the Hands (M-SACRAH) for hands/wrists. The Brief Pain Inventory (BPI) assessed pain interference, severity, and worst pain. Results Of 53 patients enrolled, 39 were evaluable at week 24. From baseline to week 24, 46 % of patients improved according to OMERACT-OARSI criteria. At week 24, there were improvements (all P<0.05) in pain and function as assessed by WOMAC and M-SACRAH, and in pain interference, severity, and worst pain as assessed by BPI. Estradiol levels did not change from baseline. The most commonly reported side effects were headache (28 %), dyspepsia (15 %), and nausea (17 %). Conclusions In this single-arm study, 24 weeks of glucosamine/chondroitin resulted in moderate improvements in AI-induced arthralgias, with minimal side effects, and no changes in estradiol levels. These results suggest a need to evaluate efficacy in a placebo-controlled trial. PMID:23111941

  8. Salivary secretory leukocyte protease inhibitor (SLPI) and head and neck cancer: The Cancer Prevention Study II Nutrition Cohort

    PubMed Central

    Campbell, Christine M. Pierce; Giuliano, Anna R.; Torres, B. Nelson; O'Keefe, Michael T.; Ingles, Donna J.; Anderson, Rebecca L.; Teras, Lauren R.; Gapstur, Susan M.

    2016-01-01

    Objectives Secretory leukocyte protease inhibitor (SLPI) is an innate-immunity protein displaying antimicrobial and anti-inflammatory properties that is found in high concentrations in saliva. The role of extracellular salivary SLPI in head and neck squamous cell carcinoma (HNSCC) remains unclear. Thus, we aimed to evaluate the association between SLPI and HNSCC risk in the Cancer Prevention Study II Nutrition Cohort. Materials and Methods Among 53,180 men and women with no history of cancer who provided an oral rinse between 2001 and 2002, 60 were subsequently diagnosed with incident HNSCC between specimen collection and June 2009. In this nested case-control study, archived oral supernatants were evaluated using the Human SLPI Quantikine ELISA Kit for all 60 cases and 180 controls individually matched on gender, race, date of birth, and date of oral rinse collection. Conditional logistic regression was used to estimate HNSCC risk. Results Overall, pre-diagnostic salivary SLPI was associated with a non-statistically significant higher risk of HNSCC (OR=1.6, 95% CI=0.9–3.0). Among never smokers, high SLPI was associated with a non-statistically significant lower risk (OR=0.5, 95% CI=0.1–1.9), whereas among ever smokers, high SLPI was associated with a statistically significant higher risk (OR=2.1, 95% CI=1.0–4.3) of HNSCC, compared to low SLPI. Conclusion While results from this study suggest that higher concentrations of salivary SLPI might increase the risk of HNSCC among ever smokers, more research is needed to verify these findings and define the mechanisms by which SLPI and smoking influence the etiology of HNSCC. PMID:27016010

  9. Biomimetic design of platelet adhesion inhibitors to block integrin α2β1-collagen interactions: II. Inhibitor library, screening, and experimental validation.

    PubMed

    Zhang, Lin; Zhang, Chao; Sun, Yan

    2014-04-29

    Platelet adhesion on collagen mediated by integrin α2β1 has been proven important in arterial thrombus formation, leading to an exigent demand on development of potent inhibitors for the integrin α2β1-collagen binding. In the present study, a biomimetic design strategy of platelet adhesion inhibitors was established, based on the affinity binding model of integrin proposed in part I. First, a heptapeptide library containing 8000 candidates was designed to functionally mimic the binding motif of integrin α2β1. Then, each heptapeptide in the library was docked onto a collagen molecule for the assessment of its affinity, followed by a screening based on its structure similarity to the original structure in the affinity binding model. Eight candidates were then selected for further screening by molecular dynamics (MD) simulations. Thereafter, three candidates chosen from MD simulations were separately added into the physiological saline containing separated integrin and collagen, to check their abilities for blocking the integrin-collagen interaction using MD simulations. Of these three candidates, significant inhibition was observed in the presence of LWWNSYY. Finally, the binding affinity of LWWNSYY for collagen was demonstrated by isothermal titration calorimetry. Moreover, significant inhibition of platelet adhesion in the presence of LWWNSYY has been experimentally validated. This work has thus developed an effective strategy for the biomimetic design of peptide-based platelet adhesion inhibitors.

  10. Role of angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and aldosterone antagonists in the prevention of atrial and ventricular arrhythmias.

    PubMed

    Makkar, Kathy M; Sanoski, Cynthia A; Spinler, Sarah A

    2009-01-01

    Atrial arrhythmias, ventricular arrhythmias, and sudden cardiac death (SCD) are significant health problems and an economic burden to society. The renin-angiotensin-aldosterone system (RAAS) may play a key role in the occurrence of structural and electrical remodeling, potentially explaining the development of atrial and ventricular arrhythmias. Angiotensin II has been shown to regulate cardiac cell proliferation and to modulate cardiac myocyte ion channels. Results of post hoc analyses from prospective clinical trials appear to show that angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are most effective in the prevention of new-onset atrial fibrillation in patients with heart failure. It is difficult to determine if these agents are useful in the prevention of new-onset atrial fibrillation after myocardial infarction, and available evidence suggests that the benefit of ACE inhibitors and ARBs for prevention of new-onset atrial fibrillation in patients with hypertension appears limited to those with left ventricular hypertrophy. Patients with structural changes in cardiac muscle, such as those with heart failure and left ventricular hypertrophy, appear to benefit the most from RAAS blockade, possibly due to the theory of reversal of cardiac remodeling. There is no evidence, to our knowledge, that either ACE inhibitors or ARBs facilitate direct electrical current cardioversion in patients with atrial fibrillation; however, it appears that RAAS blockade may be useful in the prevention of recurrent atrial fibrillation after direct electrical current cardioversion. Whether ACE inhibitors may prevent life-threatening ventricular arrhythmias or SCD is unclear. Aldosterone antagonists appear to be useful for the prevention of SCD in patients with left ventricular systolic dysfunction. Results from ongoing clinical trials are anticipated to provide further insight on the potential roles of RAAS inhibitors for the prevention of

  11. Molecular interactions of DNA-topoisomerase I and II inhibitor with DNA and topoisomerases and in ternary complexes: binding modes and biological effects for intoplicine derivatives.

    PubMed

    Nabiev, I; Chourpa, I; Riou, J F; Nguyen, C H; Lavelle, F; Manfait, M

    1994-08-02

    Molecular interactions of intoplicine, dual DNA-topoisomerases (Topo) I and II inhibitor, with topoisomerases, plasmid DNA, in ternary cleavable complexes with enzymes and plasmid DNA, and in the reversed cleavable complexes were examined by means of surface-enhanced Raman scattering (SERS) and CD spectroscopy and by biochemical techniques. Detailed spectral analysis of intoplicine derivatives allowed us to assign SERS vibrational modes of chromophores and to propose the models for these complexes. Intoplicine was found to be able to interact specifically with the Topo II alone, but with Topo I only when in the presence of DNA. It shows at least two modes of binding to the DNA: the first was found to be dominant for its derivative 1c (most potent Topo I inhibitor), and the second was dominant for derivative 2a (most potent Topo II inhibitor). The possibility of forming these two types of complexes simultaneously is suggested to be one of the main factors enabling the drug to be a dual Topo I and Topo II inhibitor. The "deep intercalation mode" of the drug from the DNA minor groove with the long axis of the chromophore oriented roughly parallel to the dyad axis has been suggested to be responsible for induction of distortions of the DNA structure by the intercalating drug. Being involved in the formation of Topo I-mediated cleavable ternary complex, the molecules participating in the deep intercalation mode within the DNA do not change their molecular interactions as compared with their complex with the DNA alone. The stabilization of the Topo I-mediated cleavable complex was shown to be followed by the local denaturation of DNA in the AT-rich regions of the helix. When the ternary cleavable complex was reversed, the drug was shown to be in the complex with the plasmid. The "outside binding mode" from the DNA major groove via the hydroxyl group of the A-ring of the chromophore has been suggested to be responsible for Topo II inhibition. These molecules did not

  12. Synthesis of 17beta-N-substituted 19-Nor-10-azasteroids as inhibitors of human 5alpha-reductases I and II.

    PubMed

    Scarpi, Dina; Occhiato, Ernesto G; Danza, Giovanna; Serio, Mario; Guarna, Antonio

    2002-11-01

    The synthesis of 17beta-[N-(phenyl)methyl/phenyl-amido] substituted 10-azasteroids has been accomplished by either the TiCl4- or TMSOTf-catalysed reaction of carbamates 11 and 12 with Danishefsky's diene. The reaction provided 5alpha-H isomers 3a-5a and 5beta-H isomers 3b-5b depending on the reaction conditions. Both epimers of each compound were tested against human 5alpha-reductase types I and II. Unexpectedly, 5beta-H compounds were found more active than their 5alpha-H counterparts, the best inhibitors being 3b (IC50=279 and 2000 nM toward isoenzyme I and II, respectively) and 5b (IC50=913 and 247 nM toward isoenzymes I and II, respectively).

  13. Losartan, a selective inhibitor of subtype AT1 receptors for angiotensin II, inhibits the binding of N-formylmethionyl-leucyl-phenylalanine to neutrophil receptors.

    PubMed

    Raiden, S; Giordano, M; Andonegui, G; Trevani, A S; López, D H; Nahmod, V; Geffner, J R

    1997-05-01

    Losartan, a selective antagonist of AT1 receptors for angiotensin II, is widely used clinically to manage hypertension. We report here that losartan markedly inhibits neutrophil shape change, adherence and chemiluminescence responses triggered by N-formylmethionyl-leucyl-phenylalanine (fMLP), without affecting responses induced by immune complexes, zymosan or concanavalin A. Neither saralasin, another antagonist of angiotensin II receptors, nor captopril, an angiotensin-converting enzyme inhibitor, reproduced the effects of losartan. It was also observed that neutrophil responses triggered by fMLP were not affected by exogenously added angiotensin II. The effect of losartan on the binding of fMLP was measured using [3H]fMLP. It was found that losartan inhibits the binding of [3H]fMLP to neutrophil receptors. As observed for neutrophils, studies performed with monocytes showed that losartan inhibits chemiluminescence emission triggered by fMLP, without affecting chemiluminescence responses triggered by immune complexes, zymosan or concanavalin A.

  14. Design and synthesis of benzothiazole-6-sulfonamides acting as highly potent inhibitors of carbonic anhydrase isoforms I, II, IX and XII.

    PubMed

    Ibrahim, Diaa A; Lasheen, Deena S; Zaky, Maysoun Y; Ibrahim, Amany W; Vullo, Daniela; Ceruso, Mariangela; Supuran, Claudiu T; Abou El Ella, Dalal A

    2015-08-01

    A series of novel 2-aminobenzothiazole derivatives bearing sulfonamide at position 6 was designed, synthesized and investigated as inhibitors of four isoforms of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1), the cytosolic CA I and II, and the tumor-associated isozymes CA IX and XII. Docking and binding energy studies were carried out to reveal details regarding the favorable interactions between the scaffolds of these new inhibitors and the active sites of the investigated CA isoforms. Most of the novel compounds were acting as highly potent inhibitors of the tumor-associated hCA IX and hCA XII with KIs in the nanomolar range. The ubiquitous and dominant rapid cytosolic isozyme hCA II was also inhibited with KIs ranging from 3.5 to 45.4 nM. The favorable interactions between some of the new compounds and the active site of different CA isoforms were delineated by using molecular docking which may be useful for designing compounds with high affinity and selectivity for some CAs with biomedical applications.

  15. Randomized controlled clinical trial of a combination therapy of vildagliptin plus an α-glucosidase inhibitor for patients with type II diabetes mellitus.

    PubMed

    Su, Yong; Su, Ya-Li; Lv, Li-Fang; Wang, Li-Min; Li, Quan-Zhong; Zhao, Zhi-Gang

    2014-06-01

    The aim of this study was to assess the efficacy of a combination therapy of vildagliptin plus an α-glucosidase inhibitor for patients with type II diabetes mellitus. Type II diabetic patients exhibiting poor glycemic control following α-glucosidase inhibitor treatment for at least two months were selected and randomly distributed into vildagliptin and placebo groups. The body weight, fasting blood glucose (FBG), postprandial glucose (PPG), glycated hemoglobin (HBA1c) and blood lipid levels and hepatorenal functions of the patients were determined before and 12 weeks after the trial. Following the trial, the FBG, PPG, HbA1c, cholesterol (CHOL) and triglyceride (TG) levels in the vildagliptin group were significantly decreased compared with the pretreatment levels (P<0.05), whereas only the PPG level in the placebo group decreased (P<0.05). The FBG, PPG and HbA1c levels in the vildagliptin group were markedly lower than those in the placebo group 12 weeks after the trial. A comparison of the body weights and hepatorenal functions before and after the trial or between groups did not show statistically significant differences. The combination therapy of vildagliptin plus an α-glucosidase inhibitor effectively reduced the FBG, PPG and HbA1c levels in patients without inducing weight gain or hepatorenal dysfunction. However, the therapy may have caused a reduction in the blood lipid levels.

  16. Inhibition of carbonic anhydrase isoforms I, II, IX and XII with novel Schiff bases: identification of selective inhibitors for the tumor-associated isoforms over the cytosolic ones.

    PubMed

    Sarikaya, Busra; Ceruso, Mariangela; Carta, Fabrizio; Supuran, Claudiu T

    2014-11-01

    A series of new Schiff bases was obtained from sulfanilamide, 3-fluorosulfanilamide or 4-(2-aminoethyl)-benzenesulfonamide and aromatic/heterocyclic aldehydes incorporating both hydrophobic and hydrophilic moieties. The obtained sulfonamides were investigated as inhibitors of four physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isoforms, the cytosolic CA I and II, as well as the transmembrane, tumor-associated CA IX and XII. Most derivatives were medium potency or weak hCA I/II inhibitors, but several of them showed nanomolar affinity for CA IX and/or XII, making them an interesting example of isoform-selective compounds. The nature of the aryl/hetaryl moiety present in the initial aldehyde was the main factor influencing potency and isoform selectivity. The best and most CA IX-selective compounds incorporated moieties such as 4-methylthiophenyl, 4-cyanophenyl-, 4-(2-pyridyl)-phenyl and the 4-aminoethylbenzenesulfonamide scaffold. The best hCA XII inhibitors, also showing selectivity for this isoform, incorporated 2-methoxy-4-nitrophenyl-, 2,3,5,6-tetrafluorophenyl and 4-(2-pyridyl)-phenyl functionalities and were also derivatives of 4-aminoethylbenzenesulfonamide. The sulfanilamide and 3-fluorosulfanilamide derived Schiff bases were less active compared to the corresponding 4-aminoethyl-benzenesulfonamide derivatives. As hCA IX/XII selective inhibition is attractive for obtaining antitumor agents/diagnostic tools with a new mechanism of action, compounds of the type described here may be considered interesting preclinical candidates.

  17. Impact of losartan and angiotensin II on the expression of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in rat vascular smooth muscle cells.

    PubMed

    Guo, Yan-Song; Wu, Zong-Gui; Yang, Jun-Ke; Chen, Xin-Jing

    2015-03-01

    The present study aimed to investigate the impact of losartan and angiotensin II (AngII) on the expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1), secreted by rat vascular smooth muscle cells (VSMCs). Rat VSMCs were isolated and cultured in different concentrations of AngII and losartan for 24 h and western blot analysis and quantitative polymerase chain reaction were performed to observe the subsequent impact on the gene and protein expression of MMP-9 and TIMP-1. AngII was shown to promote the protein and gene expression of MMP-9 in VSMCs in a concentration-dependent manner. No effect was observed on the expression of TIMP-1, therefore, an increase in the MMP-9/TIMP-1 ratio was observed. Losartan was shown to be able to inhibit MMP-9 protein and gene expression in a concentration-dependent manner, whilst promoting an increase in TIMP-1 expression, thus decreasing the ratio of MMP-9/TIMP-1. The combined action of losartan and AngII resulted in the same directional changes in MMP-9 and TIMP-1 expression as observed for losartan alone. The comparison of AngII, losartan and the combinatory effect on the expression of MMP-9 and TIMP-1 in VSMCs indicated that losartan inhibited the effects of AngII, therefore reducing the MMP-9/TIMP-1 ratio, which may contribute to the molecular mechanism of losartan in preventing atherosclerosis. In atherosclerosis, the development of the extracellular matrix of plaque is closely correlated with the evolution of AS. The balance between MMPs and TIMPs is important in maintaining the dynamic equilibrium between the ECM, and the renin-angiotensin-aldosterone system, which is involved in the pathologenesis of AS, and in which AngII has a central role.

  18. New Iminodiacetate-Thiosemicarbazone Hybrids and Their Copper(II) Complexes Are Potential Ribonucleotide Reductase R2 Inhibitors with High Antiproliferative Activity.

    PubMed

    Zaltariov, Mirela F; Hammerstad, Marta; Arabshahi, Homayon J; Jovanović, Katarina; Richter, Klaus W; Cazacu, Maria; Shova, Sergiu; Balan, Mihaela; Andersen, Niels H; Radulović, Siniša; Reynisson, Jóhannes; Andersson, K Kristoffer; Arion, Vladimir B

    2017-03-20

    As ribonucleotide reductase (RNR) plays a crucial role in nucleic acid metabolism, it is an important target for anticancer therapy. The thiosemicarbazone Triapine is an efficient R2 inhibitor, which has entered ∼20 clinical trials. Thiosemicarbazones are supposed to exert their biological effects through effectively binding transition-metal ions. In this study, six iminodiacetate-thiosemicarbazones able to form transition-metal complexes, as well as six dicopper(II) complexes, were synthesized and fully characterized by analytical, spectroscopic techniques (IR, UV-vis; (1)H and (13)C NMR), electrospray ionization mass spectrometry, and X-ray diffraction. The antiproliferative effects were examined in several human cancer and one noncancerous cell lines. Several of the compounds showed high cytotoxicity and marked selectivity for cancer cells. On the basis of this, and on molecular docking calculations one lead dicopper(II) complex and one thiosemicarbazone were chosen for in vitro analysis as potential R2 inhibitors. Their interaction with R2 and effect on the Fe(III)2-Y· cofactor were characterized by microscale thermophoresis, and two spectroscopic techniques, namely, electron paramagnetic resonance and UV-vis spectroscopy. Our findings suggest that several of the synthesized proligands and copper(II) complexes are effective antiproliferative agents in several cancer cell lines, targeting RNR, which deserve further investigation as potential anticancer drugs.

  19. Morphologic Damage of Rat Alveolar Epithelial Type II Cells Induced by Bile Acids Could Be Ameliorated by Farnesoid X Receptor Inhibitor Z-Guggulsterone In Vitro

    PubMed Central

    Huang, Yaowei; Hou, Xusheng; Wu, Wenyu; Nie, Lei; Tian, Yinghong; Lu, Yanmeng

    2016-01-01

    Objective. To determine whether bile acids (BAs) affect respiratory functions through the farnesoid X receptor (FXR) expressed in the lungs and to explore the possible mechanisms of BAs-induced respiratory disorder. Methods. Primary cultured alveolar epithelial type II cells (AECIIs) of rat were treated with different concentrations of chenodeoxycholic acid (CDCA) in the presence or absence of FXR inhibitor Z-guggulsterone (GS). Then, expression of FXR in nuclei of AECIIs was assessed by immunofluorescence microscopy. And ultrastructural changes of the cells were observed under transmission electron microscope and analyzed by Image-Pro Plus software. Results. Morphologic damage of AECIIs was exhibited in high BAs group in vitro, with high-level expression of FXR, while FXR inhibitor GS could attenuate the cytotoxicity of BAs to AECIIs. Conclusions. FXR expression was related to the morphologic damage of AECIIs induced by BAs, thus influencing respiratory functions. PMID:27340672

  20. Synthesis, characterization, antimicrobial activity and carbonic anhydrase enzyme inhibitor effects of salicilaldehyde-N-methyl p-toluenesulfonylhydrazone and its Palladium(II), Cobalt(II) complexes

    NASA Astrophysics Data System (ADS)

    Alyar, Saliha; Adem, Şevki

    2014-10-01

    We report the synthesis of the ligand, salicilaldehyde-N-methyl p-toluenesulfonylhydrazone (salptsmh) derived from p-toluenesulfonicacid-1-methylhydrazide (ptsmh) and its Pd(II) and Co(II) metal complexes were synthesized for the first time. The structure of the ligand and their complexes were investigated using elemental analysis, magnetic susceptibility, molar conductance and spectral (IR, NMR and LC-MS) measurements. Salptsmh has also been characterized by single crystal X-ray diffraction. 1H and 13C shielding tensors for crystal structure were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The complexes were found to have general composition [ML2]. The results of elemental analysis showed 1:2 (metal/ligand) stoichiometry for all the complex. Magnetic and spectral data indicate a square planar geometry for Pd(II) complex and a distorted tetrahedral geometry for Co(II) complexes. The ligand and its metal chelates have been screened for their antimicrobial activities using the disk diffusion method against the selected Gram positive bacteria: Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Gram negative bacteria: Eschericha coli, Pseudomonas aeruginosa, Klebsiella pneumonia. The inhibition activities of these compounds on carbonic anhydrase II (CA II) and carbonic anhydrase I (CA I) have been investigated by comparing IC50 and Ki values and it has been found that Pd(II) complex have more enzyme inhibition efficiency than salptsmh and Co(II) complex.

  1. Synthesis of the novel PARP-1 inhibitor AG-690/11026014 and its protective effects on angiotensin II-induced mouse cardiac remodeling.

    PubMed

    Feng, Guo-Shuai; Zhu, Cui-Ge; Li, Zhuo-Ming; Wang, Pan-Xia; Huang, Yi; Liu, Min; He, Ping; Lou, Lan-Lan; Chen, Shao-Rui; Liu, Pei-Qing

    2017-02-27

    We previously identified AG-690/11026014 (6014) as a novel poly(ADP-ribose) polymerase-1 (PARP-1) inhibitor that effectively prevented angiotensin II (Ang II)-induced cardiomyocyte hypertrophy. In the present study, we reported a new synthesis route for 6014, and investigated its protective effects on Ang II-induced cardiac remodeling and cardiac dysfunction and the underlying mechanisms in mice. We designed a new synthesis route to obtain a sufficient quantity of 6014 for this in vivo study. C57BL/6J mice were infused with Ang II and treated with 6014 (10, 30, 90 mg·kg(-1)·d(-1), ig) for 4 weeks. Then two-dimensional echocardiography was performed to assess the cardiac function and structure. Histological changes of the hearts were examined with HE staining and Masson's trichrome staining. The protein expression was evaluated by Western blot, immunohistochemistry and immunofluorescence assays. The activities of sirtuin-1 (SIRT-1) and the content of NAD+ were detected with the corresponding test kits. Treatment with 6014 dose-dependently improved cardiac function, including LVEF, CO and SV and reversed the changes of cardiac structure in Ang II-infused mice: it significantly ameliorated Ang II-induced cardiac hypertrophy evidenced by attenuating the enlargement of cardiomyocytes, decreased HW/BW and LVW/BW, and decreased expression of hypertrophic markers ANF, BNP and β-MHC; it also prevented Ang II-induced cardiac fibrosis, as implied by the decrease in excess accumulation of extracellular matrix (ECM) components collagen I, collagen III and FN. Further studies revealed that treatment with 6014 did not affect the expression levels of PARP-1, but dose-dependently inhibited the activity of PARP-1 and subsequently restored the activity of SIRT-1 in heart tissues due to the decreased consumption of NAD+ and attenuated Poly-ADP-ribosylation (PARylation) of SIRT-1. In conclusion, the novel PARP-1 inhibitor 6014 effectively protects mice against AngII-induced cardiac

  2. Discovery of dihydroxylated 2,4-diphenyl-6-thiophen-2-yl-pyridine as a non-intercalative DNA-binding topoisomerase II-specific catalytic inhibitor.

    PubMed

    Jun, Kyu-Yeon; Kwon, Hanbyeol; Park, So-Eun; Lee, Eunyoung; Karki, Radha; Thapa, Pritam; Lee, Jun-Ho; Lee, Eung-Seok; Kwon, Youngjoo

    2014-06-10

    We describe our rationale for designing specific catalytic inhibitors of topoisomerase II (topo II) over topoisomerase I (topo I). Based on 3D-QSAR studies of previously published dihydroxylated 2,4-diphenyl-6-aryl pyridine derivatives, 9 novel dihydroxylated 2,4-diphenyl-6-thiophen-2-yl pyridine compounds were designed, synthesized, and their biological activities were evaluated. These compounds have 2-thienyl ring substituted on the R(3) group on the pyridine ring and they all showed excellent specificity toward topo II compared to topo I. In vitro experiments were performed for compound 13 to determine the mechanism of action for this series of compounds. Compound 13 inhibited topoisomerase II specifically by non-intercalative binding to DNA and did not stabilize enzyme-cleavable DNA complex. Compound 13 efficiently inhibited cell viability, cell migration, and induced G1 arrest. Also from 3D-QSAR studies, the results were compared with other previously published dihydroxylated 2,4-diphenyl-6-aryl pyridine derivatives to explain the structure-activity relationships.

  3. A phase II study of the histone deacetylase inhibitor vorinostat combined with tamoxifen for the treatment of patients with hormone therapy-resistant breast cancer

    PubMed Central

    Munster, P N; Thurn, K T; Thomas, S; Raha, P; Lacevic, M; Miller, A; Melisko, M; Ismail-Khan, R; Rugo, H; Moasser, M; Minton, S E

    2011-01-01

    Background: Histone deacetylases (HDACs) are crucial components of the oestrogen receptor (ER) transcriptional complex. Preclinically, HDAC inhibitors can reverse tamoxifen/aromatase inhibitor resistance in hormone receptor-positive breast cancer. This concept was examined in a phase II combination trial with correlative end points. Methods: Patients with ER-positive metastatic breast cancer progressing on endocrine therapy were treated with 400 mg of vorinostat daily for 3 of 4 weeks and 20 mg tamoxifen daily, continuously. Histone acetylation and HDAC2 expression in peripheral blood mononuclear cells were also evaluated. Results: In all, 43 patients (median age 56 years (31–71)) were treated, 25 (58%) received prior adjuvant tamoxifen, 29 (67%) failed one prior chemotherapy regimen, 42 (98%) progressed after one, and 23 (54%) after two aromatase inhibitors. The objective response rate by Response Evaluation Criteria in Solid Tumours criteria was 19% and the clinical benefit rate (response or stable disease >24 weeks) was 40%. The median response duration was 10.3 months (confidence interval: 8.1–12.4). Histone hyperacetylation and higher baseline HDAC2 levels correlated with response. Conclusion: The combination of vorinostat and tamoxifen is well tolerated and exhibits encouraging activity in reversing hormone resistance. Correlative studies suggest that HDAC2 expression is a predictive marker and histone hyperacetylation is a useful pharmacodynamic marker for the efficacy of this combination. PMID:21559012

  4. Synthesis and evaluation of the complex-forming ability of hydroxypyranones and hydroxypyridinones with Ni (II) as possible inhibitors for urease enzyme in Helicobacter pylori

    PubMed Central

    Palizban, Abbasali; Saghaie, Lotfollah

    2016-01-01

    The complex-forming ability of 2-methyl-3-hydroxypyran-4-one (1a), 2-ethyl-3-hydroxypyran-4-one (1b), 1,2-dimethyl-3-hydroxypyridin-4-one (4a) and 1-ethyl-2-methyl-3-hydroxypyridin-4-one (4b) with nickel(Ni(II)) were characterized by infrared, ultraviolet, proton nuclear magnetic resonance spectroscopy and melting point. The mole-ratio of nickel:ligands was analyzed by atomic-absorption-spectrometry. The partition-coefficients (KOW) of the compounds were also determined. The binding of ligands with Ni(II) are through deprotonated hydroxyl group (-O-, disapeared at 3259 cm-1) and ioan-pairs of carbonyl group (=CO., shifted from 1650 to 1510-1515 cm-1). The characterization of complex geometry for bis-(2-methyl-3-hydroxypyranonato)Ni(II) (5a) and bis-(2-ethyl-3-hydroxypyranonato)Ni(II) (5b) predicted to be square-planer while for bis-(1,2-dimethyl-3-hydroxypyridinonato)Ni(II) (5c) and bis-(1-ethyl-2-methyl-3-hydroxypyridinonato)Ni(II) (5d) distorted to tetrahedral-geometry. Inhibitors of Helicobacter pylori urease are nickel chelators. The compounds 1a, 4a and 4b are likely suitable ligands with complex forming-ability to make complexes of 5a, 5c and 5d with nickel. The KOW values show the compound 5c with low partition-coefficient is more suitable ligand with lower penetration from GI lumen. Future studies demand to find out the biological activity of developed compounds on H. pylori. PMID:27651814

  5. Synthesis and evaluation of the complex-forming ability of hydroxypyranones and hydroxypyridinones with Ni (II) as possible inhibitors for urease enzyme in Helicobacter pylori.

    PubMed

    Palizban, Abbasali; Saghaie, Lotfollah

    2016-07-01

    The complex-forming ability of 2-methyl-3-hydroxypyran-4-one (1a), 2-ethyl-3-hydroxypyran-4-one (1b), 1,2-dimethyl-3-hydroxypyridin-4-one (4a) and 1-ethyl-2-methyl-3-hydroxypyridin-4-one (4b) with nickel(Ni(II)) were characterized by infrared, ultraviolet, proton nuclear magnetic resonance spectroscopy and melting point. The mole-ratio of nickel:ligands was analyzed by atomic-absorption-spectrometry. The partition-coefficients (KOW) of the compounds were also determined. The binding of ligands with Ni(II) are through deprotonated hydroxyl group (-O(-), disapeared at 3259 cm(-1)) and ioan-pairs of carbonyl group (=CO(.), shifted from 1650 to 1510-1515 cm(-1)). The characterization of complex geometry for bis-(2-methyl-3-hydroxypyranonato)Ni(II) (5a) and bis-(2-ethyl-3-hydroxypyranonato)Ni(II) (5b) predicted to be square-planer while for bis-(1,2-dimethyl-3-hydroxypyridinonato)Ni(II) (5c) and bis-(1-ethyl-2-methyl-3-hydroxypyridinonato)Ni(II) (5d) distorted to tetrahedral-geometry. Inhibitors of Helicobacter pylori urease are nickel chelators. The compounds 1a, 4a and 4b are likely suitable ligands with complex forming-ability to make complexes of 5a, 5c and 5d with nickel. The KOW values show the compound 5c with low partition-coefficient is more suitable ligand with lower penetration from GI lumen. Future studies demand to find out the biological activity of developed compounds on H. pylori.

  6. Carbonic anhydrase inhibitors: in vitro inhibition of α isoforms (hCA I, hCA II, bCA III, hCA IV) by flavonoids.

    PubMed

    Ekinci, Derya; Karagoz, Lutfi; Ekinci, Deniz; Senturk, Murat; Supuran, Claudiu T

    2013-04-01

    A series of flavonoids, such as quercetin, catechin, apigenin, luteolin, morin, were investigated for their inhibitory effects against the metalloenzyme carbonic anhydrase (CA). The compounds were tested against four α-CA isozymes purified from human and bovine (hCA I, hCA II, bCA III, hCA IV) tissues. The four isozymes showed quite diverse inhibition profiles with these compounds. The flavonoids inhibited hCA I with K(I)-s in the range of 2.2-12.8 μM, hCA II with K(I)-s in the range of 0.74-6.2 μM, bCA III with K(I)-s in the range of 2.2-21.3 μM, and hCA IV with inhibition constants in the range of 4.4-15.7, with an esterase assay using 4-nitrophenyl acetate as substrate. Some simple phenols/sulfonamides were also investigated as standard inhibitors. The flavonoids incorporate phenol moieties which inhibit these CAs through a diverse, not yet determined inhibition mechanism, compared to classic inhibitors such as the sulfonamide/sulfamate ones.

  7. Cyclooxygenase-2 inhibitors for non-small-cell lung cancer: A phase II trial and literature review.

    PubMed

    Yokouchi, Hiroshi; Kanazawa, Kenya; Ishida, Takashi; Oizumi, Satoshi; Shinagawa, Naofumi; Sukoh, Noriaki; Harada, Masao; Ogura, Shigeaki; Munakata, Mitsuru; Dosaka-Akita, Hirotoshi; Isobe, Hiroshi; Nishimura, Masaharu

    2014-09-01

    Several preclinical and clinical studies have demonstrated that cyclooxygenase-2 (COX-2) inhibitors are efficient for the treatment of non-small-cell lung cancer (NSCLC). However, two recent phase III clinical trials using COX-2 inhibitors in combination with platinum-based chemotherapy failed to demonstrate a survival benefit. Thus, validation and discussion regarding the usefulness of COX-2 inhibitors for patients with NSCLC are required. We conducted a prospective trial using COX-2 inhibitors for the treatment of 50 NSCLC patients accrued between April, 2005 and July, 2006. Patients with untreated advanced NSCLC received oral meloxicam (150 mg daily), carboplatin (area under the curve = 5 mg/ml × min on day 1) and docetaxel (60 mg/m(2) on day 1) every 3 weeks. The primary endpoint was response rate. The response and disease control rates were 36.0 and 76.0%, respectively. The time-to-progression (TTP) and overall survival (OS) were 5.7 months [95% confidence interval (CI): 4.6-6.7] and 13.7 months (95% CI: 11.4-15.9), respectively. The 1-year survival ratio was 56.0%. Grade 3 neuropathy was observed in only 1 patient. We performed tumor immunohistochemistry for COX-2 and p27 and investigated the correlation between their expression and clinical outcome. COX-2 expression in the tumor tended to correlate with a higher response rate (50.0% in the high- and 18.2% in the low-COX-2 group; P=0.092). Based on our results and previous reports, various trial designs, such as the prospective use of COX-2 inhibitors only for patients with COX-2-positive NSCLC, including the exploratory analysis of biomarkers associated with the COX-2 pathway, may be worth further consideration.

  8. Carbonic anhydrase inhibitors. Inhibition of isozymes I, II, IV, V, and IX with anions isosteric and isoelectronic with sulfate, nitrate, and carbonate.

    PubMed

    Innocenti, Alessio; Vullo, Daniela; Scozzafava, Andrea; Supuran, Claudiu T

    2005-02-01

    The inhibition of five human carbonic anhydrase (hCA, EC 4.2.1.1) isozymes; the cytosolic hCA I and II, the membrane-bound hCA IV, the mitochondrial hCA V, and the tumor-associated, transmembrane hCA IX, with anions isosteric and isoelectronic with sulfate, nitrate, and carbonate; such as chlorate, perchlorate, bromate, iodate, periodate, silicate, bismuthate, vanadate, molybdate, and wolframate is reported. Apparently, the geometry of the inhibitor (tetrahedral or trigonal) does not influence its binding to the Zn(II) ion of the enzyme active site, but the nature of the central element is the most important factor influencing potency. Isozymes hCA I and II are best inhibited by chlorate, perchlorate, and silicate, together with the anions structurally related to sulfate, sulfamate, and sulfamidate, but sulfate itself is a weak inhibitor (inhibition constant of 74 mM against hCA I and 183 mM against hCA II). Molybdate is a very weak hCA I inhibitor (K(I) of 914 mM) but it interacts with hCA II (K(I) of 27.5mM). Isozyme IV is well inhibited by sulfate (K(I) of 9 mM), sulfamate, and sulfamidate (in the low micromolar range), but not by perchlorate (K(I) of 767 mM). The mitochondrial isozyme V has the lowest affinity for sulfate (K(I) of 680 mM) and carbonate (K(I) of 95 mM) among all the investigated isozymes, suggesting on one hand its possible participation in metabolon(s) with sulfate anion exchanger(s), and on the other hand an evolutionary adaptation to working at higher pH values (around 8.5 in mitochondria) where rather high amounts of carbonate in equilibrium with bicarbonate may be present. Metasilicate, isosteric to carbonate, is also about a 10 times weaker inhibitor of this isozyme as compared to other CAs investigated here (K(I) of 28.2 mM). Surprisingly, the tumor-associated isozyme IX is resistant to sulfate inhibition (K(I) of 154 mM) but has affinity in the low micromolar range for carbonate, sulfamate, and sulfamidate (K(I) in the range of 8

  9. Purification of a specific inhibitor of pyroglutamyl aminopeptidase II from the marine annelide Hermodice carunculata. in vivo effects in rodent brain.

    PubMed

    Pascual, Isel; Gil-Parrado, Shirley; Cisneros, Miguel; Joseph-Bravo, Patricia; Díaz, Joaquín; Possani, Lourival D; Charli, Jean Louis; Chávez, María

    2004-01-01

    An inhibitor of the metallo-ectoenzyme, pyroglutamyl aminopeptidase II (PPII), a thyrotropin releasing hormone-specific peptidase, was identified by screening extracts from marine species of the Cuban coast-line belonging to the phylla Chordata, Echinodermata, Annelida, Mollusca, Cnidaria, Porifera, Chlorophyta and Magnoliophyta. Isolation of the inhibitor (HcPI), from the marine annelide Hermodice carunculata, was achieved by trichloroacetic acid treatment of the aqueous extract, followed by ion-exchange chromatography on DEAE Sephacel, gel filtration on Sephadex G-25 and reverse phase-HPLC. HcPI had a small apparent molecular weight (below 1000 Da) and was not a peptide. It inhibited rat PPII (a membrane preparation with 8.5mg protein/ml) with an apparent K(i) of 51 nM. HcPI did not inhibit serine (trypsin, chymotrypsin, elastase and dipeptidyl aminopeptidase IV), cysteine (papain, bromelain and pyroglutamyl aminopeptidase I), aspartic (pepsin and recombinant human immunodeficiency virus 1 protease (HIV1-PR)) nor other metallo proteinases (collagenase, gelatinase, angiotensin converting enzyme, aminopeptidase N and carboxypeptidase A). HcPI was non-toxic and active in vivo. Intraperitoneal injection of HcPI reduced mouse pituitary and brain PPII activity. Potency of the effect was higher in hypophysis and hypothalamus than in other brain regions. Intrathecal administration to male rats reduced PPII activity in the spinal cord. In conclusion we have identified a specific inhibitor of PPII that is the first M1 family zinc metallo-peptidase inhibitor isolated from marine invertebrates. It may be useful for elucidating the in vivo role of PPII in the pituitary and central nervous system.

  10. Synthesis, characterization, antibacterial activities and carbonic anhydrase enzyme inhibitor effects of new arylsulfonylhydrazone and their Ni(II), Co(II) complexes.

    PubMed

    Ozdemir, Ummühan Ozmen; Arslan, Fatma; Hamurcu, Fatma

    2010-01-01

    Ethane sulfonic acide hydrazide (esh: CH(3)CH(2)SO(2)NHNH(2)) derivatives as 5-methylsalicyl-aldehydeethanesulfonylhydrazone (5msalesh), 5-methyl-2-hydroxyacetophenoneethane sulfonylhydrazone (5mafesh) and their Ni(II), Co(II) complexes have been synthesized for the first time. The structure of these compounds has been investigated by elemental analysis, FT-IR, (1)H NMR, (13)C NMR, LC/MS, UV-vis spectrophotometric method, magnetic susceptibility, thermal studies and conductivity measurements. The antibacterial activities of synthesized compounds were studied against Gram positive bacteria; Staphylococcus aureus, Bacillus subtilis, Bacillus magaterium and Gram negative bacteria; Salmonella enteritidis, Escherichia coli by using the microdilution broth method. The biological activity screening showed that ligands have more activity than complexes against the tested bacteria. The inhibition activities of these compounds on carbonic anhydrase II (CA II) have been investigated by comparing IC(50) and K(i) values and it has been found that 5msalesh and its complexes have more enzyme inhibition efficiency than other compounds.

  11. Synthesis, characterization, antibacterial activities and carbonic anhydrase enzyme inhibitor effects of new arylsulfonylhydrazone and their Ni(II), Co(II) complexes

    NASA Astrophysics Data System (ADS)

    Özdemir, Ümmühan Özmen; Arslan, Fatma; Hamurcu, Fatma

    2010-01-01

    Ethane sulfonic acide hydrazide ( esh: CH 3CH 2SO 2NHNH 2) derivatives as 5-methylsalicyl-aldehydeethanesulfonylhydrazone ( 5msalesh), 5-methyl-2-hydroxyacetophenoneethane sulfonylhydrazone ( 5mafesh) and their Ni(II), Co(II) complexes have been synthesized for the first time. The structure of these compounds has been investigated by elemental analysis, FT-IR, 1H NMR, 13C NMR, LC/MS, UV-vis spectrophotometric method, magnetic susceptibility, thermal studies and conductivity measurements. The antibacterial activities of synthesized compounds were studied against Gram positive bacteria; Staphylococcus aureus, Bacillus subtilis, Bacillus magaterium and Gram negative bacteria; Salmonella enteritidis, Escherichia coli by using the microdilution broth method. The biological activity screening showed that ligands have more activity than complexes against the tested bacteria. The inhibition activities of these compounds on carbonic anhydrase II (CA II) have been investigated by comparing IC 50 and Ki values and it has been found that 5msalesh and its complexes have more enzyme inhibition efficiency than other compounds.

  12. Design, Synthesis, and Cytotoxic Evaluation of Certain 7-Chloro-4-(piperazin-1-yl)quinoline Derivatives as VEGFR-II Inhibitors.

    PubMed

    Aboul-Enein, Mohamed Nabil; El-Azzouny, Aida M Abd El-Sattar; Ragab, Fatma Abdel-Fattah; Hamissa, Mohamed Farouk

    2017-03-17

    Signaling pathway inhibition of VEGFR-II is visualized as valuable tool in cancer management. In the current study, the synthesis of novel 1-4-(7-chloroquinolin-4-yl)piperazin-1-yl)-2-(N-substituted-amino)-ethanone derivatives (4a-t) was achieved through the amination of 2-chloro-1-(4-(7-chloroquinolin-4-yl)piperazin-1-yl)ethanone (3) with different secondary amines. The structures of the target compounds were confirmed by IR, (1) H-NMR, (13) C-NMR, HRMS, and microanalysis. Compounds 4a-t were subjected to in vitro anticancer screening against human breast cancer (MCF-7) and prostate cancer (PC3) cell lines. The highest cytotoxicty against both cell lines was displayed by 2-(4-(4-bromobenzyl)piperazin-1-yl)-1-(4-(7-chloroquinolin-4-yl)piperazin-1-yl)ethanone (4q), with IC50 values of 6.502 and 11.751 μM against MCF-7 and PC3 cells, respectively, compared with the standard drug doxorubicin (MCF-7: 6.774 μM, PC3: 7.7316 μM). Due to its notable activity toward MCF-7 cells, 4q was further evaluated as VEGFR-II inhibitor, showing an IC50 of 1.38 μM compared to sorafenib (0.33 μM). The docking study proved that 4q has a binding mode akin to that of VEGFR-II inhibitors.

  13. Parkinson's disease management. Part II- discovery of MAO-B inhibitors based on nitrogen heterocycles and analogues.

    PubMed

    Reis, Joana; Encarnação, Igor; Gaspar, Alexandra; Morales, Aliuska; Milhazes, Nuno; Borges, Fernanda

    2012-01-01

    Parkinson's disease (PD) is a neurodegenerative disorder mainly characterized by a progressive neurodegeneration of the dopaminergic neurons. The available pharmacological therapy for PD aims to stop the progress of symptoms, reduce disability, slowing the neurodegenerative process and/or preventing long-term complications along the therapy. The main strategic developments that have led to progress in the medical management of PD have focused on improvements in dopaminergic therapies. Despite all the recent research, there are only a few classes of drugs approved for the treatment of motor related symptoms of PD which primarily act on the dopaminergic neurons system: L-dopa, dopamine agonists, monoamine oxidase-B (MAO-B) and catechol-O-methyl transferase (COMT) inhibitors. Anticholinergic drugs and glutamate antagonists are also available but are not commonly used in routine practice. As no effective therapeutic strategy has yet been attended, other solutions must be investigated. Privileged structures, such as indoles, arylpiperazines, biphenyls and benzopyranes are currently ascribed as helpful approaches. Different families of nitrogen and oxygen heterocycles, such as pyrazoles, hydrazinylthiazoles, xanthones, coumarins or chromones have also been extensively used as scaffolds in medicinal chemistry programs for searching novel MAO-B inhibitors. Nitrogen derivatives play a key role in this subject with several studies pointing out hydrazines, thiazoles or indoles as important scaffolds for the development of novel MAO-B inhibitors. This review comprises an overview of the state of the art on the actual pharmacological therapy for PD followed by a specific focus on the discovery and development of nitrogen-based heterocyclic compounds analogues as promising MAO-B inhibitors.

  14. Sex differences in the enhanced responsiveness to acute angiotensin II in growth-restricted rats: role of fasudil, a Rho kinase inhibitor

    PubMed Central

    Ojeda, Norma B.; Royals, Thomas P.

    2013-01-01

    This study tested the hypothesis that Rho kinase contributes to the enhanced pressor response to acute angiotensin II in intact male growth-restricted and gonadectomized female growth-restricted rats. Mean arterial pressure (MAP) and renal function were determined in conscious animals pretreated with enalapril (250 mg/l in drinking water) for 1 wk to block the endogenous renin-angiotensin system and normalize blood pressure (baseline). Blood pressure and renal hemodynamics did not differ at baseline. Acute Ang II (100 ng·kg−1·min−1) induced a greater increase in MAP and renal vascular resistance and enhanced reduction in glomerular filtration rate in intact male growth-restricted rats compared with intact male controls (P < 0.05). Cotreatment with the Rho kinase inhibitor fasudil (33 μg·kg−1·min−1) significantly attenuated these hemodynamic changes (P < 0.05), but it did not abolish the differential increase in blood pressure above baseline, suggesting that the impact of intrauterine growth restriction on blood pressure in intact male growth-restricted rats is independent of Rho kinase. Gonadectomy in conjunction with fasudil returned blood pressure back to baseline in male growth-restricted rats, and yet glomerular filtration rate remained significantly reduced (P < 0.05). Thus, these data suggest a role for enhanced renal sensitivity to acute Ang II in the developmental programming of hypertension in male growth-restricted rats. However, inhibition of Rho kinase had no effect on the basal or enhanced increase in blood pressure induced by acute Ang II in the gonadectomized female growth-restricted rat. Therefore, these studies suggest that Rho kinase inhibition exerts a sex-specific effect on blood pressure sensitivity to acute Ang II in growth-restricted rats. PMID:23344570

  15. Synthesis and biological evaluation of NAS-21 and NAS-91 analogues as potential inhibitors of the mycobacterial FAS-II dehydratase enzyme Rv0636.

    PubMed

    Bhowruth, Veemal; Brown, Alistair K; Besra, Gurdyal S

    2008-07-01

    The identification of potential new anti-tubercular chemotherapeutics is paramount due to the recent emergence of extensively drug-resistant strains of Mycobacterium tuberculosis (XDR-TB). Libraries of NAS-21 and NAS-91 analogues were synthesized and evaluated for their whole-cell activity against Mycobacterium bovis BCG. NAS-21 analogues 1 and 2 demonstrated enhanced whole-cell activity in comparison to the parental compound, and an M. bovis BCG strain overexpressing the dehydratase enzyme Rv0636 was resistant to these analogues. NAS-91 analogues with ortho-modifications gave enhanced whole-cell activity. However, extension with biphenyl modifications compromised the whole-cell activities of both NAS-21 and NAS-91 analogues. Interestingly, both libraries demonstrated in vitro activity against fatty acid synthase II (FAS-II) but not FAS-I in cell-free extracts. In in vitro assays of FAS-II inhibition, NAS-21 analogues 4 and 5 had IC(50) values of 28 and 19 mug ml(-1), respectively, for the control M. bovis strain, and the M. bovis BCG strain overexpressing Rv0636 showed a marked increase in resistance. In contrast, NAS-91 analogues demonstrated moderate in vitro activity, although increased resistance was again observed in FAS-II activity assays with the Rv0636-overexpressing strain. Fatty acid methyl ester (FAME) and mycolic acid methyl ester (MAME) analysis of M. bovis BCG and the Rv0636-overexpressing strain revealed that the effect of the drug was relieved in the overexpressing strain, further implicating and potentially identifying Rv0636 as the target for these known FabZ dehydratase inhibitors. This study has identified candidates for further development as drug therapeutics against the mycobacterial FAS-II dehydratase enzyme.

  16. Platelet-derived miR-92a downregulates cysteine protease inhibitor cystatin C in type II diabetic lower limb ischemia

    PubMed Central

    ZHANG, YUNFENG; GUAN, QIANG; JIN, XING

    2015-01-01

    The aim of the present study was to investigate the effect of microRNA (miR)-92a on cystatin C expression in patients with type II diabetes and lower limb ischemia. A total of 199 patients diagnosed with type II diabetes were included in the study and divided into three experimental groups: Simple type II diabetes mellitus (T2DM; n=60) group; type II diabetes with light to moderate occlusion (LLI-LM; n=70) group; and the type II diabetes with severe occlusion (LLI-S; n=69) group according to the patient ankle-brachial index score. In addition, 60 healthy individuals were examined as a control population. The expression levels of various biochemical indices were detected, including cystatin C in the peripheral blood. The expression levels of miR-92a and cystatin C mRNA were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and the correlation between miR-92a, cystatin C and the pathological development of type II diabetic lower limb ischemia was analyzed. The protein expression levels of cystatin C were detected using western blot analysis. Bioinformatic analysis indicated that miR-92a was able to downregulate cystatin C expression, and this result was supported by endothelial cell transfection. In the transfection assay, an miR-92a mimic downregulated cystatin C expression, while an miR-92a inhibitor upregulated cystatin C expression. The results of the RT-qPCR indicated that the expression levels of miR-92a in the LLI-S group were reduced compared with those in the T2DM and LLI-LM groups, and significantly lower compared with those in the negative control group. Platelet-derived miR-92a appeared to downregulate cystatin C expression in patients with type II diabetes and lower limb ischemia. Therefore, the combined detection of miR-92a and cystatin C may be useful as a method for clinically screening patients with type II diabetes for lower limb ischemia. PMID:26136970

  17. Carbonic anhydrase inhibitors. Inhibition of human cytosolic isoforms I and II with (reduced) Schiff's bases incorporating sulfonamide, carboxylate and carboxymethyl moieties.

    PubMed

    Nasr, Gihane; Cristian, Alina; Barboiu, Mihail; Vullo, Daniella; Winum, Jean-Yves; Supuran, Claudiu T

    2014-05-15

    A library of Schiff bases was synthesized by condensation of aromatic amines incorporating sulfonamide, carboxylic acid or carboxymethyl functionalities as Zn(2+)-binding groups, with aromatic aldehydes incorporating tert-butyl, hydroxy and/or methoxy groups. The corresponding amines were thereafter obtained by reduction of the imines. These compounds were assayed for the inhibition of two cytosolic human carbonic anhydrase (hCA, EC 4.2.1.1) isoenzymes, hCA I and II. The Ki values of the Schiff bases were in the range of 7.0-21,400nM against hCA II and of 52-8600nM against hCA I, respectively. The corresponding amines showed Ki values in the range of 8.6nM-5.3μM against hCA II, and of 18.7-251nM against hCA I, respectively. Unlike the imines, the reduced Schiff bases are stable to hydrolysis and several low-nanomolar inhibitors were detected, most of them incorporating sulfonamide groups. Some carboxylates also showed interesting CA inhibitory properties. Such hydrosoluble derivatives may show pharmacologic applications.

  18. Kinetics and molecular docking studies of cholinesterase inhibitors derived from water layer of Lycopodiella cernua (L.) Pic. Serm. (II).

    PubMed

    Hung, Tran Manh; Lee, Joo Sang; Chuong, Nguyen Ngoc; Kim, Jeong Ah; Oh, Sang Ho; Woo, Mi Hee; Choi, Jae Sue; Min, Byung Sun

    2015-10-05

    Acetylcholinesterase (AChE) inhibitors increase the availability of acetylcholine in central cholinergic synapses and are the most promising drugs currently available for the treatment of Alzheimer's disease (AD). Our screening study indicated that the water fraction of the methanolic extract of Lycopodiella cernua (L.) Pic. Serm. significantly inhibited AChE in vitro. Bioassay-guided fractionation led to the isolation of a new lignan glycoside, lycocernuaside A (12), and fourteen known compounds (1-11 and 13-15). Compound 7 exhibited the most potent AChE inhibitory activity with an IC50 value of 0.23 μM. Compound 15 had the most potent inhibitory activity against BChE and BACE1 with IC50 values of 0.62 and 2.16 μM, respectively. Compounds 4 and 7 showed mixed- and competitive-type AChE inhibition. Compound 7 noncompetitively inhibited BChE whereas 15 showed competitive and 8, 13, and 14 showed mixed-type inhibition. The docking results for complexes with AChE or BChE revealed that inhibitors 4, 7, and 15 stably positioned themselves in several pocket/catalytic domains of the AChE and BChE residues.

  19. Design and synthesis of thiazolo[5,4-f]quinazolines as DYRK1A inhibitors, part II.

    PubMed

    Foucourt, Alicia; Hédou, Damien; Dubouilh-Benard, Carole; Girard, Angélique; Taverne, Thierry; Casagrande, Anne-Sophie; Désiré, Laurent; Leblond, Bertrand; Besson, Thierry

    2014-09-26

    The convenient synthesis of a focused library (forty molecules) of novel 6,6,5-tricyclic thiazolo[5,4-f]quinazolines was realized mainly under microwave irradiation. A novel 6-aminobenzo[d]thiazole-2,7-dicarbonitrile (1) was used as a versatile molecular platform for the synthesis of various derivatives. Kinase inhibition, of the obtained final compounds, was evaluated on a panel of two kinases (DYRK1A/1B) together with some known reference DYRK1A and DYRK1B inhibitors (harmine, TG003, NCGC-00189310 and leucettine L41). Compound IC50 values were obtained and compared. Five of the novel thiazolo[5,4-f]quinazoline derivatives prepared, EHT 5372 (8c), EHT 6840 (8h), EHT 1610 (8i), EHT 9851 (8k) and EHT 3356 (9b) displayed single-digit nanomolar or subnanomolar IC50 values and are among the most potent DYRK1A/1B inhibitors disclosed to date. DYRK1A/1B kinases are known to be involved in the regulation of various molecular pathways associated with oncology, neurodegenerative diseases (such as Alzheimer disease, AD, or other tauopathies), genetic diseases (such as Down Syndrome, DS), as well as diseases involved in abnormal pre-mRNA splicing. The compounds described in this communication constitute a highly potent set of novel molecular probes to evaluate the biology/pharmacology of DYR1A/1B in such diseases.

  20. Carbonic Anhydrase Inhibitors. Part 551 Metal Complexes of 1,3,4-Thiadiazole-2-Sulfonamide Derivatives: In Vitro Inhibition Studies With Carbonic Anhydrase Isozymes I, II and IV

    PubMed Central

    Scozzafava, Andrea; Briganti, Fabrizio; Ilies, Marc A.; Jitianu, Andrei

    1998-01-01

    Coordination compounds of 5-chloroacetamido-1,3,4-thiadiazole-2-sulfonamide (Hcaz) with V(IV), Cr(lll), Fe(ll), Co(ll), Ni(ll) and Cu(ll) have been prepared and characterized by standard procedures (spectroscopic, magnetic, EPR, thermogravimetric and conductimetric measurements). Some of these compounds showed very good in vitro inhibitory properties against three physiologically relevant carbonic anhydrase (CA)isozymes, i.e., CA I, II, and IV. The differences between these isozymes in susceptibility to inhibition by these metal complexes is discussed in relationship to the characteristic features of their active sites, and is rationalized in terms useful for developing isozyme-specific CA inhibitors. PMID:18475829

  1. Predicting cyclooxygenase inhibition by three-dimensional pharmacophoric profiling. Part II: Identification of enzyme inhibitors from Prasaplai, a Thai traditional medicine

    PubMed Central

    Waltenberger, Birgit; Schuster, Daniela; Paramapojn, Sompol; Gritsanapan, Wandee; Wolber, Gerhard; Rollinger, Judith M.; Stuppner, Hermann

    2011-01-01

    Prasaplai is a medicinal plant mixture that is used in Thailand to treat primary dysmenorrhea, which is characterized by painful uterine contractility caused by a significant increase of prostaglandin release. Cyclooxygenase (COX) represents a key enzyme in the formation of prostaglandins. Former studies revealed that extracts of Prasaplai inhibit COX-1 and COX-2. In this study, a comprehensive literature survey for known constituents of Prasaplai was performed. A multiconformational 3D database was created comprising 683 molecules. Virtual parallel screening using six validated pharmacophore models for COX inhibitors was performed resulting in a hit list of 166 compounds. 46 Prasaplai components with already determined COX activity were used for the external validation of this set of COX pharmacophore models. 57% of these components were classified correctly by the pharmacophore models. These findings confirm that the virtual approach provides a helpful tool (i) to unravel which molecular compounds might be responsible for the COX-inhibitory activity of Prasaplai and (ii) for the fast identification of novel COX inhibitors. PMID:20851587

  2. Ca2+/calmodulin-dependent kinase II contributes to inhibitor of nuclear factor-kappa B kinase complex activation in Helicobacter pylori infection.

    PubMed

    Maubach, Gunter; Sokolova, Olga; Wolfien, Markus; Rothkötter, Hermann-Josef; Naumann, Michael

    2013-09-15

    Helicobacter pylori, a class I carcinogen, induces a proinflammatory response by activating the transcription factor nuclear factor-kappa B (NF-κB) in gastric epithelial cells. This inflammatory condition could lead to chronic gastritis, which is epidemiologically and biologically linked to the development of gastric cancer. So far, there exists no clear knowledge on how H. pylori induces the NF-κB-mediated inflammatory response. In our study, we investigated the role of Ca(2+) /calmodulin-dependent kinase II (CAMKII), calmodulin, protein kinases C (PKCs) and the CARMA3-Bcl10-MALT1 (CBM) complex in conjunction with H. pylori-induced activation of NF-κB via the inhibitor of nuclear factor-kappa B kinase (IKK) complex. We use specific inhibitors and/or RNA interference to assess the contribution of these components. Our results show that CAMKII and calmodulin contribute to IKK complex activation and thus to the induction of NF-κB in response to H. pylori infection, but not in response to TNF-α. Thus, our findings are specific for H. pylori infected cells. Neither the PKCs α, δ, θ, nor the CBM complex itself is involved in the activation of NF-κB by H. pylori. The contribution of CAMKII and calmodulin, but not PKCs/CBM to the induction of an inflammatory response by H. pylori infection augment the understanding of the molecular mechanism involved and provide potential new disease markers for the diagnosis of gastric inflammatory diseases including gastric cancer.

  3. Effects of a myosin-II inhibitor (N-benzyl-p-toluene sulphonamide, BTS) on contractile characteristics of intact fast-twitch mammalian muscle fibres.

    PubMed

    Pinniger, G J; Bruton, J D; Westerblad, H; Ranatunga, K W

    2005-01-01

    We have examined the effects of N-benzyl-p-toluene sulphonamide (BTS), a potent and specific inhibitor of fast muscle myosin-II, using small bundles of intact fibres or single fibres from rat foot muscle. BTS decreased tetanic tension reversibly in a concentration-dependent manner with half-maximal inhibition at approximately approximately 2 microM at 20 degrees C. The inhibition of tension with 10 microM BTS was marked at the three temperatures examined (10, 20 and 30 degrees C), but greatest at 10 degrees C. BTS decreased active muscle stiffness to a lesser extent than tetanic tension indicating that not all of the tension inhibition was due to a reduced number of attached cross-bridges. BTS-induced inhibition of active tension was not accompanied by any change in the free myoplasmic Ca2+ transients. The potency and specificity of BTS make it a very suitable myosin inhibitor for intact mammalian fast muscle and should be a useful tool for the examination of outstanding questions in muscle contraction.

  4. Impact of Angiotensin I-converting Enzyme Inhibitors and Angiotensin II Type-1 Receptor Blockers on Survival of Patients with NSCLC

    PubMed Central

    Miao, Lili; Chen, Wei; Zhou, Ling; Wan, Huanying; Gao, Beili; Feng, Yun

    2016-01-01

    It has been shown that angiotensin I-converting enzyme inhibitors (ACEIs) and angiotensin II type-1 receptor blockers (ARBs) can decrease tumor growth and tumor-associated angiogenesis and inhibit metastasis. Epidermal growth factor receptor (EGFR) mutations are found in approximately 30% of patients with advanced non-small cell lung cancer (NSCLC) in East Asia and in 10–15% of such patients in Western countries. We retrospectively identified 228 patients with histologically confirmed advanced NSCLC and 73 patients with early stage disease; 103 of these patients took antihypertensive drugs, and 112 received treatment with EGFR tyrosine kinase inhibitors (TKIs). There was a significant difference in progression-free survival after first-line therapy (PFS1) between the ACEI/ARB group and the non-ACEI/ARB group. For the patients treated with TKIs, there was a significant difference in PFS but not in overall survival (OS) between the ACEI/ARB group and the non-ACEI/ARB group. For the patients with advanced NSCLC, there was a significant difference in PFS1 between the ACEI/ARB group and the non-ACEI/ARB group. ACEI/ARB in combination with standard chemotherapy or TKIs had a positive effect on PFS1 or OS, regardless of whether the lung cancer was in the early or advanced stage. PMID:26883083

  5. Carbonic anhydrase inhibitors: guaiacol and catechol derivatives effectively inhibit certain human carbonic anhydrase isoenzymes (hCA I, II, IX and XII).

    PubMed

    Scozzafava, Andrea; Passaponti, Maurizio; Supuran, Claudiu T; Gülçin, İlhami

    2015-01-01

    Carbonic anhydrases (CAs) are widespread metalloenzymes in higher vertebrates including humans. A series of phenolic compounds, including guaiacol, 4-methylguaiacol, 4-propylguaiacol, eugenol, isoeugenol, vanillin, syringaldehyde, catechol, 3-methyl catechol, 4-methyl catechol and 3-methoxy catechol were investigated for their inhibition of all the catalytically active mammalian isozymes of the Zn(2+)-containing CA (EC 4.2.1.1). All the phenolic compounds effectively inhibited human carbonic anhydrase isoenzymes (hCA I, II, IX and XII), with Kis in the range of 2.20-515.98 μM. The various isozymes showed diverse inhibition profiles. Among the tested phenolic derivatives, compounds 4-methyl catechol and 3-methoxy catechol showed potent activity as inhibitors of the tumour-associated transmembrane isoforms (hCA IX and XII) in the submicromolar range, with high selectivity. The results obtained from this research may lead to the design of more effective carbonic anhydrase isoenzyme inhibitors (CAIs) based on such phenolic compound scaffolds.

  6. Comparison of three development approaches for Stationary Phase Optimised Selectivity Liquid Chromatography based screening methods Part II: A group of structural analogues (PDE-5 inhibitors in food supplements).

    PubMed

    Deconinck, E; Ghijs, L; Kamugisha, A; Courselle, P

    2016-02-01

    Three approaches for the development of a screening method to detect adulterated dietary supplements, based on Stationary Phase Optimised Selectivity Liquid Chromatography were compared for their easiness/speed of development and the performance of the optimal method obtained. This comparison was performed for a heterogeneous group of molecules, i.e. slimming agents (Part I) and a group of structural analogues, i.e. PDE-5 inhibitors (Part II). The first approach makes use of primary runs at one isocratic level, the second of primary runs in gradient mode and the third of primary runs at three isocratic levels to calculate the optimal combination of segments of stationary phases. In each approach the selection of the stationary phase was followed by a gradient optimisation. For the PDE-5 inhibitors, the group of structural analogues, only the method obtained with the third approach was able to differentiate between all the molecules in the development set. Although not all molecules are baseline separated, the method allows the identification of the selected adulterants in dietary supplements using only diode array detection. Though, due to the mobile phases used, the method could also be coupled to mass spectrometry. The method was validated for its selectivity following the guidelines as described for the screening of pesticide residues and residues of veterinary medicines in food.

  7. Utilization of Boron Compounds for the Modification of Suberoyl Anilide Hydroxamic Acid as Inhibitor of Histone Deacetylase Class II Homo sapiens

    PubMed Central

    Bakri, Ridla; Parikesit, Arli Aditya; Satriyanto, Cipta Prio; Kerami, Djati; Tambunan, Usman Sumo Friend

    2014-01-01

    Histone deacetylase (HDAC) has a critical function in regulating gene expression. The inhibition of HDAC has developed as an interesting anticancer research area that targets biological processes such as cell cycle, apoptosis, and cell differentiation. In this study, an HDAC inhibitor that is available commercially, suberoyl anilide hydroxamic acid (SAHA), has been modified to improve its efficacy and reduce the side effects of the compound. Hydrophobic cap and zinc-binding group of these compounds were substituted with boron-based compounds, whereas the linker region was substituted with p-aminobenzoic acid. The molecular docking analysis resulted in 8 ligands with ΔGbinding value more negative than the standards, SAHA and trichostatin A (TSA). That ligands were analyzed based on the nature of QSAR, pharmacological properties, and ADME-Tox. It is conducted to obtain a potent inhibitor of HDAC class II Homo sapiens. The screening process result gave one best ligand, Nova2 (513246-99-6), which was then further studied by molecular dynamics simulations. PMID:25214833

  8. Ability of four potential topoisomerase II inhibitors to enhance the cytotoxicity of cis-diamminedichloroplatinum (II) in Chinese hamster ovary cells and in an epipodophyllotoxin-resistant subline.

    PubMed

    Eder, J P; Teicher, B A; Holden, S A; Senator, L; Cathcart, K N; Schnipper, L E

    1990-01-01

    Four drugs known to interact with topoisomerase II were assessed for their ability to enhance the cytotoxicity of cis-diamminedichloroplatinum(II) (CDDP) in Chinese hamster ovary (CHO) cell lines sensitive and resistant to VM-26. The combination treatments were analyzed by isobologram methodology. On 24 h exposure, there was no significant difference in the cytotoxicity of novobiocin or ciprofloxacin toward either cell line. The resistant cells were approximately 9-fold more resistant to 4'-(9-acridinylamino)methanesulfon-m-anisidide (m-AMSA) and approximately 170-fold more resistant to etoposide after a 24-h exposure. The combination of novobiocin and cisplatin produced greater than additive cell kill over the entire dose range of cisplatin tested in both cell lines. m-AMSA and CDDP produced cell kill that fell within the envelope of additivity. Etoposide and CDDP resulted in cytotoxicity that was slightly greater than additive at low CDDP concentrations and additive at the highest concentration of CDDP tested in the parental cell line and was slightly greater than additive in the resistant cell line. Ciprofloxacin and CDDP, like novobiocin, resulted in greater than additive cell kill in both cell lines. The enhancement of CDDP cytotoxicity by novobiocin that was seen in exponentially growing cells was lost in stationary-phase cultures. In these studies, novobiocin and, to a lesser degree, ciprofloxacin produced greater than additive cell kill in combination with CDDP in parental and epipodophyllotoxin-resistant CHO cells.

  9. Induction of unique structural changes in guanine-rich DNA regions by the triazoloacridone C-1305, a topoisomerase II inhibitor with antitumor activities

    PubMed Central

    Lemke, Krzysztof; Wojciechowski, Marcin; Laine, William; Bailly, Christian; Colson, Pierre; Baginski, Maciej; Larsen, Annette K.; Skladanowski, Andrzej

    2005-01-01

    We recently reported that the antitumor triazoloacridone, compound C-1305, is a topoisomerase II poison with unusual properties. In this study we characterize the DNA interactions of C-1305 in vitro, in comparison with other topoisomerase II inhibitors. Our results show that C-1305 binds to DNA by intercalation and possesses higher affinity for GC- than AT-DNA as revealed by surface plasmon resonance studies. Chemical probing with DEPC indicated that C-1305 induces structural perturbations in DNA regions with three adjacent guanine residues. Importantly, this effect was highly specific for C-1305 since none of the other 22 DNA interacting drugs tested was able to induce similar structural changes in DNA. Compound C-1305 induced stronger structural changes in guanine triplets at higher pH which suggested that protonation/deprotonation of the drug is important for this drug-specific effect. Molecular modeling analysis predicts that the zwitterionic form of C-1305 intercalates within the guanine triplet, resulting in widening of both DNA grooves and aligning of the triazole ring with the N7 atoms of guanines. Our results show that C-1305 binds to DNA and induces very specific and unusual structural changes in guanine triplets which likely plays an important role in the cytotoxic and antitumor activity of this unique compound. PMID:16254080

  10. A phase I/II study of the pan Bcl-2 inhibitor obatoclax mesylate plus bortezomib for relapsed or refractory mantle cell lymphoma.

    PubMed

    Goy, André; Hernandez-Ilzaliturri, Francisco J; Kahl, Brad; Ford, Peggy; Protomastro, Ewelina; Berger, Mark

    2014-12-01

    Obatoclax, a BH3 mimetic inhibitor of anti-apoptotic Bcl-2 proteins, demonstrates synergy with bortezomib in preclinical models of mantle cell lymphoma (MCL). This phase I/II study assessed obatoclax plus bortezomib in patients with relapsed/refractory MCL. Twenty-three patients received obatoclax 30 or 45 mg plus bortezomib 1.0 or 1.3 mg/m(2), administered intravenously on days 1, 4, 8 and 11 of a 21-day cycle. In phase I, the combination was feasible at all doses. Obatoclax 45 mg plus bortezomib 1.3 mg/m(2) was selected for phase II study. Common adverse events were somnolence (87%), fatigue (61%) and euphoric mood (57%), all primarily grade 1/2. Grade 3/4 events included thrombocytopenia (21%), anemia (13%) and fatigue (13%). Objective responses occurred in 4/13 (31%) evaluable patients (three complete and one partial response). Six patients (46%) had stable disease lasting ≥ 8 weeks. Obatoclax plus bortezomib was feasible, but the synergy demonstrated in preclinical models was not confirmed.

  11. Biological activities of Zn(II)-S-methyl-cysteine complex as antiradical, inhibitor of acid phosphatase enzyme and in vivo antidepressant effects.

    PubMed

    Escudero, Graciela E; Martini, Nancy; Jori, Khalil; Jori, Nadir; Maresca, Nahuel R; Laino, Carlos H; Naso, Luciana G; Williams, Patricia A M; Ferrer, Evelina G

    2016-12-01

    The antidepressant effect of simple Zn(II) salts has been proved in several animal models of depression. In this study, a coordination metal complex of Zn(II) having a sulfur containing ligand is tested as antidepressant for the first time. Forced swimming test method on male Wistar rats shows a decrease in the immobility and an increase in the swimming behavior after treatment with [Zn(S-Met)2] (S-Met=S-methyl-l-cysteine) being more effective and remarkable than ZnCl2. The thiobarbituric acid and the pyranine consumption (hydroxyl and peroxyl radicals, respectively) methods were applied to evaluate the antioxidant activity of S-Met and [Zn(S-Met)2] showing evidence of attenuation of hydroxyl but not peroxyl radicals activities. UV-vis studies on the inhibition of acid phosphatase enzyme (AcP) demonstrated that S-methyl-l-cysteine did not produce any effect but, in contrast, [Zn(S-Met)2] complex behaved as a moderate inhibitor. Finally, bioavailability studies were performed by fluorescence spectroscopy denoting the ability of the albumin to transport the complex.

  12. Kinetics of successive seeding of monodisperse polystyrene latexes. I - Initiation via potassium persulfate. II - Azo initiators with and without inhibitors

    NASA Technical Reports Server (NTRS)

    Sudol, E. D.; El-Aasser, M. S.; Vanderhoff, J. W.

    1986-01-01

    The polymerization kinetics of monodisperse polystyrene latexes with diameters of 1 micron are studied. The monodisperse latexes were prepared by the successive seeding method using 1 mM K2S2O8 with an 8 percent emulsifier surface coverage and 0.5 mM K2S2O8 with a 4 percent emulsifier surface coverage, and the kinetics were measured in a piston/cylinder dialometer. The data reveal that the polymerization rate decreases with increasing particle size; and the surface charge decreases with increasing particle size. The effects of initiators (AIBN and AMBN) and inhibitors (NH24SCN, NaNO2, and hydroquinone) on the product monodispersity and polymerization kinetics of latexes with diameters greater than 1 micron are investigated in a second experiment. It is observed that hydroquinone combined with AMBN are most effective in reducing nucleation without causing flocculation. It is noted that the kinetic transition from emulsion to bulk is complete for a particle size exceeding 1 micron in which the polymerization rate is independent of the particle size.

  13. Mechanism of action of the antibiotic NXL101, a novel nonfluoroquinolone inhibitor of bacterial type II topoisomerases.

    PubMed

    Black, Michael T; Stachyra, Thérèse; Platel, Denis; Girard, Anne-Marie; Claudon, Monique; Bruneau, Jean-Michel; Miossec, Christine

    2008-09-01

    NXL101 is one of a new class of quinoline antibacterial DNA gyrase and topoisomerase IV inhibitors showing potent activity against gram-positive bacteria, including methicillin- and fluoroquinolone-resistant strains. NXL101 inhibited topoisomerase IV more effectively than gyrase from Escherichia coli, whereas the converse is true of enzymes from Staphylococcus aureus. This apparent target preference is opposite to that which is associated with most fluoroquinolone antibiotics. In vitro isolation of S. aureus mutants resistant to NXL101 followed by cloning and sequencing of the genes encoding gyrase and topoisomerase IV led to the identification of several different point mutations within, or close to, the quinolone resistance-determining region (QRDR) of GyrA. However, the mutations were not those that are most frequently associated with decreased sensitivity to quinolones. A fluoroquinolone-resistant mutant variant of gyrase generated in vitro was highly resistant to inhibition by the fluoroquinolones ciprofloxacin and moxifloxacin but remained fully susceptible to inhibition by NXL101. Two mutant gyrases constructed in vitro, with mutations in gyrA engineered according to those most frequently found in S. aureus strains resistant to NXL101, were insensitive to inhibition by NXL101 and had a diminished sensitivity to ciprofloxacin and moxifloxacin. Certain combinations of mutations giving rise to NXL101 resistance and those giving rise to fluoroquinolone resistance may be mutually exclusive.

  14. The dipeptidyl peptidase inhibitor linagliptin and the angiotensin II receptor blocker telmisartan show renal benefit by different pathways in rats with 5/6 nephrectomy.

    PubMed

    Tsuprykov, Oleg; Ando, Ryotaro; Reichetzeder, Christoph; von Websky, Karoline; Antonenko, Viktoriia; Sharkovska, Yuliya; Chaykovska, Lyubov; Rahnenführer, Jan; Hasan, Ahmed A; Tammen, Harald; Alter, Markus; Klein, Thomas; Ueda, Seiji; Yamagishi, Sho-Ichi; Okuda, Seiya; Hocher, Berthold

    2016-05-01

    Dipeptidyl peptidase (DPP)-4 inhibitors delay chronic kidney disease (CKD) progression in experimental diabetic nephropathy in a glucose-independent manner. Here we compared the effects of the DPP-4 inhibitor linagliptin versus telmisartan in preventing CKD progression in non-diabetic rats with 5/6 nephrectomy. Animals were allocated to 1 of 4 groups: sham operated plus placebo; 5/6 nephrectomy plus placebo; 5/6 nephrectomy plus linagliptin; and 5/6 nephrectomy plus telmisartan. Interstitial fibrosis was significantly decreased by 48% with linagliptin but a non-significant 24% with telmisartan versus placebo. The urine albumin-to-creatinine ratio was significantly decreased by 66% with linagliptin and 92% with telmisartan versus placebo. Blood pressure was significantly lowered by telmisartan, but it was not affected by linagliptin. As shown by mass spectrometry, the number of altered peptide signals for linagliptin in plasma was 552 and 320 in the kidney. For telmisartan, there were 108 peptide changes in plasma and 363 in the kidney versus placebo. Linagliptin up-regulated peptides derived from collagen type I, apolipoprotein C1, and heterogeneous nuclear ribonucleoproteins A2/B1, a potential downstream target of atrial natriuretic peptide, whereas telmisartan up-regulated angiotensin II. A second study was conducted to confirm these findings in 5/6 nephrectomy wild-type and genetically deficient DPP-4 rats treated with linagliptin or placebo. Linagliptin therapy in wild-type rats was as effective as DPP-4 genetic deficiency in terms of albuminuria reduction. Thus, linagliptin showed comparable efficacy to telmisartan in preventing CKD progression in non-diabetic rats with 5/6 nephrectomy. However, the underlying pathways seem to be different.

  15. Midostaurin, a Novel Protein Kinase Inhibitor for the Treatment of Acute Myelogenous Leukemia: Insights from Human Absorption, Metabolism and Excretion Studies of a BDDCS II Drug.

    PubMed

    He, Handan; Tran, Phi; Gu, Helen; Tedesco, Vivienne; Zhang, Jin; Lin, Wen; Gatlik, Ewa; Klein, Kai; Heimbach, Tycho

    2017-03-07

    The absorption, metabolism and excretion of midostaurin, a potent class III tyrosine protein kinase inhibitor for acute myelogenous leukemia, were evaluated in healthy subjects. A microemulsion formulation was chosen to optimize absorption. After a 50 mg [14C]midostaurin dose, oral absorption was high (> 90%) and relatively rapid. In plasma, the major circulating components were midostaurin (22%), CGP52421 (32.7%), and CGP62221 (27.7%). Long plasma half-lives were observed for midostaurin (20.3 h), CGP52421 (495 h), and CGP62221 (33.4 h). Through careful mass-balance study design, the recovery achieved was good (81.6%), despite the long radioactivity half-lives. Most of the radioactive dose was recovered in feces (77.6%) mainly as metabolites; as only 3.43% was unchanged, suggesting mainly hepatic metabolism. Renal elimination was minor (4%). Midostaurin metabolism pathways involved hydroxylation, O demethylation, amide hydrolysis and N demethylation. High plasma CGP52421 and CGP62221 exposures in humans, along with relatively potent cell-based IC50 for FLT3-ITD inhibition, suggested that the antileukemic activity in AML patients may also be maintained by the metabolites. Very high plasma protein binding (>99%) required equilibrium gel filtration to identify differences between humans and animals. As midostaurin, CGP52421 and CGP62221 are metabolized mainly by CYP3A4 and are inhibitors/inducers for CYP3A, potential drug-drug interactions with mainly CYP3A4 modulators/CYP3A substrates could be expected. Given its low aqueous solubility, high oral absorption and extensive metabolism (> 90%), midostaurin is a BCS/BDDCS class II drug in human, consistent with rat BDDCS in vivo data showing high absorption (>90%) and extensive metabolism (>90%).

  16. Synthesis, characterization, computational studies, antimicrobial activities and carbonic anhydrase inhibitor effects of 2-hydroxy acetophenone-N-methyl p-toluenesulfonylhydrazone and its Co(II), Pd(II), Pt(II) complexes

    NASA Astrophysics Data System (ADS)

    Özbek, Neslihan; Alyar, Saliha; Memmi, Burcu Koçak; Gündüzalp, Ayla Balaban; Bahçeci, Zafer; Alyar, Hamit

    2017-01-01

    2-Hydroxyacetophenone-N-methyl p-toluenesulfonylhydrazone (afptsmh) derived from p-toluenesulfonicacid-1-methylhydrazide (ptsmh) and its Co(II), Pd(II), Pt(II) complexes were synthesized for the first time. Synthesized compounds were characterized by spectroscopic methods (FT-IR, 1Hsbnd 13C NMR, LC-MS, UV-vis), magnetic susceptibility and conductivity measurements. 1H and 13C shielding tensors for crystal structure of ligand were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The vibrational band assignments were performed at B3LYP/6-311++G(d,p) theory level combined with scaled quantum mechanics force field (SQMFF) methodology. The antibacterial activities of synthesized compounds were studied against some Gram positive and Gram negative bacteria by using microdilution and disc diffusion methods. In vitro enzyme inhibitory effects of the compounds were measured by UV-vis spectrophotometer. The enzyme activities against human carbonic anhydrase II (hCA II) were evaluated as IC50 (the half maximal inhibitory concentration) values. It was found that afptsmh and its metal complexes have inhibitory effects on hCA II isoenzyme. General esterase activities were determined using alpha and beta naphtyl acetate substrates (α- and β-NAs) of Drosophila melanogaster (D. melanogaster). Activity results show that afptsmh does not strongly affect the bacteria strains and also shows poor inhibitory activity against hCAII isoenzyme whereas all complexes posses higher biological activities.

  17. Valproic Acid, a Histone Deacetylase Inhibitor, in Combination with Paclitaxel for Anaplastic Thyroid Cancer: Results of a Multicenter Randomized Controlled Phase II/III Trial

    PubMed Central

    Pugliese, Mariateresa; Gallo, Marco; Brignardello, Enrico; Milla, Paola; Orlandi, Fabio; Limone, Paolo Piero; Arvat, Emanuela; Boccuzzi, Giuseppe; Piovesan, Alessandro

    2016-01-01

    Anaplastic thyroid cancer (ATC) has a median survival less than 5 months and, to date, no effective therapy exists. Taxanes have recently been stated as the main drug treatment for ATC, and the histone deacetylase inhibitor valproic acid efficiently potentiates the effects of paclitaxel in vitro. Based on these data, this trial assessed the efficacy and safety of the combination of paclitaxel and valproic acid for the treatment of ATC. This was a randomized, controlled phase II/III trial, performed on 25 ATC patients across 5 centers in northwest Italy. The experimental arm received the combination of paclitaxel (80 mg/m2/weekly) and valproic acid (1,000 mg/day); the control arm received paclitaxel alone. Overall survival and disease progression, evaluated in terms of progression-free survival, were the primary outcomes. The secondary outcome was the pharmacokinetics of paclitaxel. The coadministration of valproic acid did not influence the pharmacokinetics of paclitaxel. Neither median survival nor median time to progression was statistically different in the two arms. Median survival of operated-on patients was significantly better than that of patients who were not operated on. The present trial demonstrates that the addition of valproic acid to paclitaxel has no effect on overall survival and disease progression of ATC patients. This trial is registered with EudraCT 2008-005221-11. PMID:27766105

  18. Induction of heat-shock response and alterations of protein phosphorylation by a novel topoisomerase II inhibitor, withangulatin A, in 9L rat brain tumor cells.

    PubMed

    Lee, W C; Lin, K Y; Chen, C M; Chen, Z T; Liu, H J; Lai, Y K

    1991-10-01

    Withangulatin A is a newly identified in vitro topoisomerase II inhibitor isolated from the Chinese antitumor herb Physalis angulata. In vivo, it was found to be cytotoxic, capable of suppressing general protein synthesis and of inducing the synthesis of a small set of proteins including those generated by heat-shock treatment. The 70 kDa protein generated by withangulatin A was unequivocally identified as the heat-shock protein 70 (HSP70) since both proteins migrated to the same position on two-dimensional polyacrylamide gels, could be recognized by a monoclonal antibody to human HSP70, and exhibited identical peptide maps. The induction of protein synthesis by withangulatin A was regulated at the transcriptional level since it was aborted in cells pre-treated with actinomycin D. However, the initiation of this process did not require de novo protein synthesis since it was not affected by cycloheximide. Other cellular effect of withangulatin A was alterations of protein phosphorylation including an enhancement of phosphorylation of a 65 kDa protein which was also detected in the heat-shocked cells. Moreover, this process was observed within 7.5 min after the initial heat treatment which is much faster than the onset of HSP synthesis. Therefore, increased phosphorylation of the 65 kDa protein may represent one of the earliest signals generated by both heat-shock and withangluatin A and may be involved in the upstream regulation of heat-shock response in cells.

  19. Genetic Resistance Determinants, In Vitro Time-Kill Curve Analysis and Pharmacodynamic Functions for the Novel Topoisomerase II Inhibitor ETX0914 (AZD0914) in Neisseria gonorrhoeae

    PubMed Central

    Foerster, Sunniva; Golparian, Daniel; Jacobsson, Susanne; Hathaway, Lucy J.; Low, Nicola; Shafer, William M.; Althaus, Christian L.; Unemo, Magnus

    2015-01-01

    Resistance in Neisseria gonorrhoeae to all available therapeutic antimicrobials has emerged and new efficacious drugs for treatment of gonorrhea are essential. The topoisomerase II inhibitor ETX0914 (also known as AZD0914) is a new spiropyrimidinetrione antimicrobial that has different mechanisms of action from all previous and current gonorrhea treatment options. In this study, the N. gonorrhoeae resistance determinants for ETX0914 were further described and the effects of ETX0914 on the growth of N. gonorrhoeae (ETX0914 wild type, single step selected resistant mutants, and efflux pump mutants) were examined in a novel in vitro time-kill curve analysis to estimate pharmacodynamic parameters of the new antimicrobial. For comparison, ciprofloxacin, azithromycin, ceftriaxone, and tetracycline were also examined (separately and in combination with ETX0914). ETX0914 was rapidly bactericidal for all wild type strains and had similar pharmacodynamic properties to ciprofloxacin. All selected resistant mutants contained mutations in amino acid codons D429 or K450 of GyrB and inactivation of the MtrCDE efflux pump fully restored the susceptibility to ETX0914. ETX0914 alone and in combination with azithromycin and ceftriaxone was highly effective against N. gonorrhoeae and synergistic interaction with ciprofloxacin, particularly for ETX0914-resistant mutants, was found. ETX0914, monotherapy or in combination with azithromycin (to cover additional sexually transmitted infections), should be considered for phase III clinical trials and future gonorrhea treatment. PMID:26696986

  20. Intra-nucleus accumbens administration of the calcium/calmodulin-dependent protein kinase II inhibitor AIP induced antinociception in rats with mononeuropathy.

    PubMed

    Bian, Hui; Yu, Long-Chuan

    2015-07-10

    Calcium/calmodulin-dependent protein kinase II (CaMKII) is a serine/threonine- dependent protein kinase, which has been implicated in pain modulation at different levels of the central nervous system. The present study was performed in rats with mononeuropathy induced by left common sciatic nerve ligation. Unilateral sciatic nerve loose ligation produced decreases in the hindpaw withdrawal latency (HWL) to noxious thermal and mechanical stimulation. Intra-nucleus accumbens (NAc) injection of 3 μg, 6 μg and 12 μg of myristoylated autocamtide-2-inhibitory peptide (AIP), the CaMKII inhibitor, dose-dependently increased the HWL to noxious thermal and mechanical stimulation in rats with mononeuropathy. Furthermore, intra-NAc administration of morphine, the HWL to noxious thermal and mechanical stimulation increased markedly, and there were no significant differences between morphine group and AIP group. Taken together, the results showed that intra-NAc injection of AIP induced significant antinociceptive effects in rats with mononeuropathy, indicating that CaMKII may play an important role in the transmission and/or modulation of nociceptive information in the NAc in rats with mononeuropathy.

  1. Genetic Resistance Determinants, In Vitro Time-Kill Curve Analysis and Pharmacodynamic Functions for the Novel Topoisomerase II Inhibitor ETX0914 (AZD0914) in Neisseria gonorrhoeae.

    PubMed

    Foerster, Sunniva; Golparian, Daniel; Jacobsson, Susanne; Hathaway, Lucy J; Low, Nicola; Shafer, William M; Althaus, Christian L; Unemo, Magnus

    2015-01-01

    Resistance in Neisseria gonorrhoeae to all available therapeutic antimicrobials has emerged and new efficacious drugs for treatment of gonorrhea are essential. The topoisomerase II inhibitor ETX0914 (also known as AZD0914) is a new spiropyrimidinetrione antimicrobial that has different mechanisms of action from all previous and current gonorrhea treatment options. In this study, the N. gonorrhoeae resistance determinants for ETX0914 were further described and the effects of ETX0914 on the growth of N. gonorrhoeae (ETX0914 wild type, single step selected resistant mutants, and efflux pump mutants) were examined in a novel in vitro time-kill curve analysis to estimate pharmacodynamic parameters of the new antimicrobial. For comparison, ciprofloxacin, azithromycin, ceftriaxone, and tetracycline were also examined (separately and in combination with ETX0914). ETX0914 was rapidly bactericidal for all wild type strains and had similar pharmacodynamic properties to ciprofloxacin. All selected resistant mutants contained mutations in amino acid codons D429 or K450 of GyrB and inactivation of the MtrCDE efflux pump fully restored the susceptibility to ETX0914. ETX0914 alone and in combination with azithromycin and ceftriaxone was highly effective against N. gonorrhoeae and synergistic interaction with ciprofloxacin, particularly for ETX0914-resistant mutants, was found. ETX0914, monotherapy or in combination with azithromycin (to cover additional sexually transmitted infections), should be considered for phase III clinical trials and future gonorrhea treatment.

  2. Novel N-linked aminopiperidine inhibitors of bacterial topoisomerase type II with reduced pK(a): antibacterial agents with an improved safety profile.

    PubMed

    Reck, Folkert; Alm, Richard A; Brassil, Patrick; Newman, Joseph V; Ciaccio, Paul; McNulty, John; Barthlow, Herbert; Goteti, Kosalaram; Breen, John; Comita-Prevoir, Janelle; Cronin, Mark; Ehmann, David E; Geng, Bolin; Godfrey, Andrew Aydon; Fisher, Stewart L

    2012-08-09

    Novel non-fluoroquinolone inhibitors of bacterial type II topoisomerases (DNA gyrase and topoisomerase IV) are of interest for the development of new antibacterial agents that are not impacted by target-mediated cross-resistance with fluoroquinolones. N-Linked amino piperidines, such as 7a, generally show potent antibacterial activity, including against quinolone-resistant isolates, but suffer from hERG inhibition (IC(50) = 44 μM for 7a) and QT prolongation in vivo. We now disclose the finding that new analogues of 7a with reduced pK(a) due to substitution with an electron-withdrawing substituent in the piperidine moiety, such as R,S-7c, retained the Gram-positive activity of 7a but showed significantly less hERG inhibition (IC(50) = 233 μM for R,S-7c). This compound exhibited moderate clearance in dog, promising efficacy against a MRSA strain in a mouse infection model, and an improved in vivo QT profile as measured in a guinea pig in vivo model. As a result of its promising activity, R,S-7c was advanced into phase I clinical studies.

  3. Icariside II, a natural mTOR inhibitor, disrupts aberrant energy homeostasis via suppressing mTORC1-4E-BP1 axis in sarcoma cells

    PubMed Central

    Zhang, Chao; Yang, Lei; Geng, Ya-di; An, Fa-liang; Xia, Yuan-zheng; Guo, Chao; Luo, Jian-guang; Zhang, Lu-yong; Guo, Qing-long; Kong, Ling-yi

    2016-01-01

    The aberrant energy homeostasis that characterized by high rate of energy production (glycolysis) and energy consumption (mRNA translation) is associated with the development of cancer. As mammalian target of rapamycin (mTOR) is a critical regulator of aberrant energy homeostasis, it is an attractive target for anti-tumor intervention. The flavonoid compound Icariside II (IS) is a natural mTOR inhibitor derived from Epimedium. Koreanum. Herein, we evaluate the effect of IS on aberrant energy homeostasis. The reduction of glycolysis and mRNA translation in U2OS (osteosarcoma), S180 (fibrosarcoma) and SW1535 (chondrosarcoma) cells observed in our study, indicate that, IS inhibits aberrant energy homeostasis. This inhibition is found to be due to suppression of mammalian target of rapamycin complex 1 (mTORC1)-eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) axis through blocking the assembly of mTORC1. Furthermore, IS inhibits the cap-dependent translation of c-myc through mTORC1-4E-BP1 axis which links the relationship between mRNA translation and glycolysis. Inhibition of aberrant energy homeostasis by IS, contributes to its in vitro and in vivo anti-proliferation activity. These data indicate that IS disrupts aberrant energy homeostasis of sarcoma cells through suppression of mTORC1-4E-BP1 axis, providing a novel mechanism of IS to inhibit cell proliferation in sarcoma cells. PMID:27056897

  4. Re-evaluation of the side effects of cytochrome b6f inhibitor dibromothymoquinone on photosystem II excitation and electron transfer.

    PubMed

    Belatik, Ahmed; Joly, David; Hotchandani, Surat; Carpentier, Robert

    2013-11-01

    Dibromothymoquinone (DBMIB) has been used as a specific inhibitor of plastoquinol oxidation at the Q0 binding site of the cytochrome b6f complex for 40 years. It is thought to suppress electron transfer between photosystem (PS) II and I, as well as cyclic electron transfer around PSI. However, DBMIB has also been reported to act as a quencher of chlorophyll excited states. In this study, we have re-evaluated the effects of DBMIB on chlorophyll excited states and PSII photochemistry. The results show that DBMIB significantly quenches the chlorophyll excited states of PSII antenna even at low concentration (from 0.1 μM), lowering the effective excitation rate of the actinic light. It also acts as a potent PSII electron acceptor retarding the reduction of the plastoquinone pool with almost maximal potency at 2 μM. Altogether, these results suggest that experiments using DBMIB can easily be misinterpreted and stress on the importance of taking into account all these side effects that occur in the same range of DBMIB concentration used for inhibition of plastoquinol oxidation (1 μM).

  5. The versatile binding mode of transition-state analogue inhibitors of tyrosinase towards dicopper(II) model complexes: experimental and theoretical investigations.

    PubMed

    Orio, Maylis; Bochot, Constance; Dubois, Carole; Gellon, Gisèle; Hardré, Renaud; Jamet, Hélène; Luneau, Dominique; Philouze, Christian; Réglier, Marius; Serratrice, Guy; Belle, Catherine

    2011-11-25

    We describe 2-mercaptopyridine-N-oxide (HSPNO) as a new and efficient competitive inhibitor of mushroom tyrosinase (K(IC) =3.7 μM). Binding studies of HSPNO and 2-hydroxypyridine-N-oxide (HOPNO) on dinuclear copper(II) complexes [Cu(2)(BPMP)(μ-OH)](ClO(4))(2) (1; HBPMP=2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methylphenol) and [Cu(2)(BPEP)(μ-OH)](ClO(4))(2)) (2; HBPEP=2,6-bis{bis[2-(2-pyridyl)ethyl]aminomethyl}-4-methylphenol), known to be functional models for the tyrosinase diphenolase activity, have been performed. A combination of structural data, spectroscopic studies, and DFT calculations evidenced the adaptable binding mode (bridging versus chelating) of HOPNO in relation to the geometry and chelate size of the dicopper center. For comparison, binding studies of HSPNO and kojic acid (5-hydroxy-2-(hydroxymethyl)-4-pyrone) on dinuclear complexes were performed. A theoretical approach has been developed and validated on HOPNO adducts to compare the binding mode on the model complexes. It has been applied for HSPNO and kojic acid. Although results for HSPNO were in line with those obtained with HOPNO, thus reflecting their chemical similarity, we showed that the bridging mode was the most preferential binding mode for kojic acid on both complexes.

  6. 3D QSAR studies, pharmacophore modeling, and virtual screening of diarylpyrazole-benzenesulfonamide derivatives as a template to obtain new inhibitors, using human carbonic anhydrase II as a model protein.

    PubMed

    Entezari Heravi, Yeganeh; Sereshti, Hassan; Saboury, Ali Akbar; Ghasemi, Jahan; Amirmostofian, Marzieh; Supuran, Claudiu T

    2017-12-01

    A 3D-QSAR modeling was performed on a series of diarylpyrazole-benzenesulfonamide derivatives acting as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1). The compounds were collected from two datasets with the same scaffold, and utilized as a template for a new pharmacophore model to screen the ZINC database of commercially available derivatives. The datasets were divided into training, test, and validation sets. As the first step, comparative molecular field analysis (CoMFA), CoMFA region focusing and comparative molecular similarity indices analysis (CoMSIA) in parallel with docking studies were applied to a set of 41 human (h) CA II inhibitors. The validity and the prediction capacity of the resulting models were evaluated by leave-one-out (LOO) cross-validation approach. The reliability of the model for the prediction of possibly new CA inhibitors was also tested.

  7. I. Development of Metal-Mediated SPOT-Synthesis Methods for the Efficient Construction of Small-Molecule Macroarrays. II. Design and Synthesis of Novel Bacterial Biofilm Inhibitors

    NASA Astrophysics Data System (ADS)

    Frei, Reto

    I. The use of small molecule probes to explore biological phenomena has become a valuable tool in chemical biology. As a result, methods that permit the rapid synthesis and biological evaluation of such compounds are highly sought-after. The small molecule macroarray represents one such approach for the synthesis and identification of novel bioactive agents. Macroarrays are readily constructed via the SPOT-synthesis technique on planar cellulose membranes, yielding spatially addressed libraries of ˜10-1000 unique compounds. We sought to expand the arsenal of chemical reactions compatible with this solid-phase platform, and developed highly efficient SPOT-synthesis protocols for the Mizoroki-Heck, Suzuki-Miyaura, and copper-catalyzed azide-alkyne cycloaddition reaction. We demonstrated that these metal-mediated reactions can be implemented, either individually or sequentially, for the efficient construction of small molecules in high purity on rapid time scales. Utilizing these powerful C-C and C-N bond forming coupling reactions, we constructed a series of macroarrays based on novel stilbene, phenyl-naphthalene, and triazole scaliblds. Subsequent biological testing of the stilbene and phenyl-naphthalene libraries revealed several potent antagonists and agonists, respectively, of the quorum sensing (QS) receptor LuxR in Vibrio fischeri. II. Bacteria living within biofilms are notorious for their resistance to known antibiotic agents, and constitute a major human health threat. Methods to attenuate biofilm growth would have a significant impact on the management of bacterial infections. Despite intense research efforts, small molecules capable of either inhibiting or dispersing biolilms remain scarce. We utilized natural products with purported anti-biofilm or QS inhibitory activity as sources of structural insight to guide the synthesis of novel biofilm modulators with improved activities. These studies revealed 2-aminobenzimidazole derivatives as highly potent

  8. The putative P-gp inhibitor telmisartan does not affect the transcellular permeability and cellular uptake of the calcium channel antagonist verapamil in the P-glycoprotein expressing cell line MDCK II MDR1

    PubMed Central

    Saaby, Lasse; Tfelt-Hansen, Peer; Brodin, Birger

    2015-01-01

    Verapamil is used in high doses for the treatment of cluster headache. Verapamil has been described as a P-glycoprotein (P-gp, ABCB1) substrate. We wished to evaluate in vitro whether co administration of a P-gp inhibitor with verapamil could be a feasible strategy for increasing CNS uptake of verapamil. Fluxes of radiolabelled verapamil across MDCK II MDR1 monolayers were measured in the absence and presence of the putative P-gp inhibitor telmisartan (a clinically approved drug compound). Verapamil displayed a vectorial basolateral-to-apical transepithelial efflux across the MDCK II MDR1 monolayers with a permeability of 5.7 × 10−5 cm sec−1 compared to an apical to basolateral permeability of 1.3 × 10−5 cm sec-1. The efflux could be inhibited with the P-gp inhibitor zosuquidar. Zosuquidar (0.4 μmol/L) reduced the efflux ratio (PB-A/PA-B) for verapamil 4.6–1.6. The presence of telmisartan, however, only caused a slight reduction in P-gp-mediated verapamil transport to an efflux ratio of 3.4. Overall, the results of the present in vitro approach indicate, that clinical use of telmisartan as a P-gp inhibitor may not be an effective strategy for increasing brain uptake of verapamil by co-administration with telmisartan. PMID:26171231

  9. Molecular Recognition of the Catalytic Zinc(II) Ion in MMP-13: Structure-Based Evolution of an Allosteric Inhibitor to Dual Binding Mode Inhibitors with Improved Lipophilic Ligand Efficiencies

    PubMed Central

    Fischer, Thomas; Riedl, Rainer

    2016-01-01

    Matrix metalloproteinases (MMPs) are a class of zinc dependent endopeptidases which play a crucial role in a multitude of severe diseases such as cancer and osteoarthritis. We employed MMP-13 as the target enzyme for the structure-based design and synthesis of inhibitors able to recognize the catalytic zinc ion in addition to an allosteric binding site in order to increase the affinity of the ligand. Guided by molecular modeling, we optimized an initial allosteric inhibitor by addition of linker fragments and weak zinc binders for recognition of the catalytic center. Furthermore we improved the lipophilic ligand efficiency (LLE) of the initial inhibitor by adding appropriate zinc binding fragments to lower the clogP values of the inhibitors, while maintaining their potency. All synthesized inhibitors showed elevated affinity compared to the initial hit, also most of the novel inhibitors displayed better LLE. Derivatives with carboxylic acids as the zinc binding fragments turned out to be the most potent inhibitors (compound 3 (ZHAWOC5077): IC50 = 134 nM) whereas acyl sulfonamides showed the best lipophilic ligand efficiencies (compound 18 (ZHAWOC5135): LLE = 2.91). PMID:26938528

  10. Molecular Recognition of the Catalytic Zinc(II) Ion in MMP-13: Structure-Based Evolution of an Allosteric Inhibitor to Dual Binding Mode Inhibitors with Improved Lipophilic Ligand Efficiencies.

    PubMed

    Fischer, Thomas; Riedl, Rainer

    2016-03-01

    Matrix metalloproteinases (MMPs) are a class of zinc dependent endopeptidases which play a crucial role in a multitude of severe diseases such as cancer and osteoarthritis. We employed MMP-13 as the target enzyme for the structure-based design and synthesis of inhibitors able to recognize the catalytic zinc ion in addition to an allosteric binding site in order to increase the affinity of the ligand. Guided by molecular modeling, we optimized an initial allosteric inhibitor by addition of linker fragments and weak zinc binders for recognition of the catalytic center. Furthermore we improved the lipophilic ligand efficiency (LLE) of the initial inhibitor by adding appropriate zinc binding fragments to lower the clogP values of the inhibitors, while maintaining their potency. All synthesized inhibitors showed elevated affinity compared to the initial hit, also most of the novel inhibitors displayed better LLE. Derivatives with carboxylic acids as the zinc binding fragments turned out to be the most potent inhibitors (compound 3 (ZHAWOC5077): IC50 = 134 nM) whereas acyl sulfonamides showed the best lipophilic ligand efficiencies (compound 18 (ZHAWOC5135): LLE = 2.91).

  11. Development and use of a high-throughput bacterial DNA gyrase assay to identify mammalian topoisomerase II inhibitors with whole-cell anticancer activity.

    PubMed

    Roychoudhury, Siddhartha; Makin, Kelly M; Twinem, Tracy L; Stanton, David T; Nelson, Sandra L; Catrenich, Carl E

    2003-04-01

    A high-throughput screen (HTS) was developed and used to identify inhibitors of bacterial DNA gyrase. Among the validated hits were 53 compounds that also inhibited mammalian topoisomerase II with IC(50) values of <12.5 micro g/mL for 51 of them. Using computational methods, these compounds were subjected to cluster analysis to categorize them according to their chemical and structural properties. Nine compounds from different clusters were tested for their whole-cell inhibitory activity against 3 cancer cell lines-NCI-H460 (lung), MCF7 (breast), and SF-268 (CNS)-at a concentration of 100 micro M. Five compounds inhibited cell growth by >50% for all 3 cell lines tested. These compounds were tested further against a panel of 53 to 57 cell lines representing leukemia, melanoma, colon, CNS, ovarian, renal, prostate, breast, and non-small cell lung cancers. In this assay, PGE-7143417 was found to be the most potent compound, which inhibited the growth of all the cell lines by 50% at a concentration range of 0.31 to 2.58 micro M, with an average of 1.21 micro M. An additional 17 compounds were also tested separately against a panel of 10 cell lines representing melanoma, colon, lung, mammary, ovarian, prostate, and renal cancers. In this assay, 4 compounds-PGE-3782569, PGE-7411516, PGE-2908955, and PGE-3521917-were found to have activity with concentrations for 50% cell growth inhibition in the 0.59 to 3.33, 22.5 to 59.1, 7.1 to >100, and 24.7 to >100 micro M range.

  12. Primary analysis of a phase II open-label trial of INCB039110, a selective JAK1 inhibitor, in patients with myelofibrosis

    PubMed Central

    Mascarenhas, John O.; Talpaz, Moshe; Gupta, Vikas; Foltz, Lynda M.; Savona, Michael R.; Paquette, Ronald; Turner, A. Robert; Coughlin, Paul; Winton, Elliott; Burn, Timothy C.; O’Neill, Peter; Clark, Jason; Hunter, Deborah; Assad, Albert; Hoffman, Ronald; Verstovsek, Srdan

    2017-01-01

    Combined Janus kinase 1 (JAK1) and JAK2 inhibition therapy effectively reduces splenomegaly and symptom burden related to myelofibrosis but is associated with dose-dependent anemia and thrombocytopenia. In this open-label phase II study, we evaluated the efficacy and safety of three dose levels of INCB039110, a potent and selective oral JAK1 inhibitor, in patients with intermediate- or high-risk myelofibrosis and a platelet count ≥50×109/L. Of 10, 45, and 32 patients enrolled in the 100 mg twice-daily, 200 mg twice-daily, and 600 mg once-daily cohorts, respectively, 50.0%, 64.4%, and 68.8% completed week 24. A ≥50% reduction in total symptom score was achieved by 35.7% and 28.6% of patients in the 200 mg twice-daily cohort and 32.3% and 35.5% in the 600 mg once-daily cohort at week 12 (primary end point) and 24, respectively. By contrast, two patients (20%) in the 100 mg twice-daily cohort had ≥50% total symptom score reduction at weeks 12 and 24. For the 200 mg twice-daily and 600 mg once-daily cohorts, the median spleen volume reductions at week 12 were 14.2% and 17.4%, respectively. Furthermore, 21/39 (53.8%) patients who required red blood cell transfusions during the 12 weeks preceding treatment initiation achieved a ≥50% reduction in the number of red blood cell units transfused during study weeks 1–24. Only one patient discontinued for grade 3 thrombocytopenia. Non-hematologic adverse events were largely grade 1 or 2; the most common was fatigue. Treatment with INCB039110 resulted in clinically meaningful symptom relief, modest spleen volume reduction, and limited myelosuppression. PMID:27789678

  13. Discovery and characterization of a novel potent type II native and mutant BCR-ABL inhibitor (CHMFL-074) for Chronic Myeloid Leukemia (CML).

    PubMed

    Liu, Feiyang; Wang, Beilei; Wang, Qiang; Qi, Ziping; Chen, Cheng; Kong, Lu-Lu; Chen, Ji-Yun; Liu, Xiaochuan; Wang, Aoli; Hu, Chen; Wang, Wenchao; Wang, Huiping; Wu, Fan; Ruan, Yanjie; Qi, Shuang; Liu, Juan; Zou, Fengming; Hu, Zhenquan; Wang, Wei; Wang, Li; Zhang, Shanchun; Yun, Cai-Hong; Zhai, Zhimin; Liu, Jing; Liu, Qingsong

    2016-07-19

    BCR gene fused ABL kinase is the critical driving force for the Philadelphia Chromosome positive (Ph+) Chronic Myeloid Leukemia (CML) and has been extensively explored as a drug target. With a structure-based drug design approach we have discovered a novel inhibitor CHMFL-074, that potently inhibits both the native and a variety of clinically emerged mutants of BCR-ABL kinase. The X-ray crystal structure of CHMFL-074 in complex with ABL1 kinase (PDB ID: 5HU9) revealed a typical type II binding mode (DFG-out) but relatively rare hinge binding. Kinome wide selectivity profiling demonstrated that CHMFL-074 bore a high selectivity (S score(1) = 0.03) and potently inhibited ABL1 kinase (IC50: 24 nM) and PDGFR α/β (IC50: 71 nM and 88 nM). CHMFL-074 displayed strong anti-proliferative efficacy against BCR-ABL-driven CML cell lines such as K562 (GI50: 56 nM), MEG-01 (GI50: 18 nM) and KU812 (GI50: 57 nM). CHMFL-074 arrested cell cycle into the G0/G1 phase and induced apoptosis in the Ph+ CML cell lines. In addition, it potently inhibited the CML patient primary cell's proliferation but did not affect the normal bone marrow cells. In the CML cell K562 inoculated xenograft mouse model, oral administration of 100 mg/kg/d of CHMFL-074 achieved a tumor growth inhibition (TGI) of 65% without exhibiting apparent toxicity. As a potential drug candidate for fighting CML, CHMFL-074 is under extensive preclinical safety evaluation now.

  14. Discovery and characterization of a novel potent type II native and mutant BCR-ABL inhibitor (CHMFL-074) for Chronic Myeloid Leukemia (CML)

    PubMed Central

    Chen, Ji-Yun; Liu, Xiaochuan; Wang, Aoli; Hu, Chen; Wang, Wenchao; Wang, Huiping; Wu, Fan; Ruan, Yanjie; Qi, Shuang; Liu, Juan; Zou, Fengming; Hu, Zhenquan; Wang, Wei; Wang, Li; Zhang, Shanchun; Yun, Cai-Hong; Zhai, Zhimin; Liu, Jing; Liu, Qingsong

    2016-01-01

    BCR gene fused ABL kinase is the critical driving force for the Philadelphia Chromosome positive (Ph+) Chronic Myeloid Leukemia (CML) and has been extensively explored as a drug target. With a structure-based drug design approach we have discovered a novel inhibitor CHMFL-074, that potently inhibits both the native and a variety of clinically emerged mutants of BCR-ABL kinase. The X-ray crystal structure of CHMFL-074 in complex with ABL1 kinase (PDB ID: 5HU9) revealed a typical type II binding mode (DFG-out) but relatively rare hinge binding. Kinome wide selectivity profiling demonstrated that CHMFL-074 bore a high selectivity (S score(1) = 0.03) and potently inhibited ABL1 kinase (IC50: 24 nM) and PDGFR α/β (IC50: 71 nM and 88 nM). CHMFL-074 displayed strong anti-proliferative efficacy against BCR-ABL–driven CML cell lines such as K562 (GI50: 56 nM), MEG-01 (GI50: 18 nM) and KU812 (GI50: 57 nM). CHMFL-074 arrested cell cycle into the G0/G1 phase and induced apoptosis in the Ph+ CML cell lines. In addition, it potently inhibited the CML patient primary cell's proliferation but did not affect the normal bone marrow cells. In the CML cell K562 inoculated xenograft mouse model, oral administration of 100 mg/kg/d of CHMFL-074 achieved a tumor growth inhibition (TGI) of 65% without exhibiting apparent toxicity. As a potential drug candidate for fighting CML, CHMFL-074 is under extensive preclinical safety evaluation now. PMID:27322145

  15. VEGFR tyrosine kinase inhibitor II (VRI) induced vascular insufficiency in zebrafish as a model for studying vascular toxicity and vascular preservation

    SciTech Connect

    Li, Shang; Dang, Yuan Ye; Oi Lam Che, Ginny; Kwan, Yiu Wa; Chan, Shun Wan; Leung, George Pak Heng; Lee, Simon Ming Yuen; Hoi, Maggie Pui Man

    2014-11-01

    In ischemic disorders such as chronic wounds and myocardial ischemia, there is inadequate tissue perfusion due to vascular insufficiency. Besides, it has been observed that prolonged use of anti-angiogenic agents in cancer therapy produces cardiovascular toxicity caused by impaired vessel integrity and regeneration. In the present study, we used VEGFR tyrosine kinase inhibitor II (VRI) to chemically induce vascular insufficiency in zebrafish in vivo and human umbilical vein endothelial cells (HUVEC) in vitro to further study the mechanisms of vascular morphogenesis in these pathological conditions. We also explored the possibility of treating vascular insufficiency by enhancing vascular regeneration and repair with pharmacological intervention. We observed that pretreatment of VRI induced blood vessel loss in developing zebrafish by inhibiting angiogenesis and increasing endothelial cell apoptosis, accompanied by down-regulation of kdr, kdrl and flt-1 genes expression. The VRI-induced blood vessel loss in zebrafish could be restored by post-treatment of calycosin, a cardiovascular protective isoflavone. Similarly, VRI induced cytotoxicity and apoptosis in HUVEC which could be rescued by calycosin post-treatment. Further investigation of the underlying mechanisms showed that the PI3K/AKT/Bad cell survival pathway was a main contributor of the vascular regenerative effect of calycosin. These findings indicated that the cardiovascular toxicity in anti-angiogenic therapy was mainly caused by insufficient endothelial cell survival, suggesting its essential role in vascular integrity, repair and regeneration. In addition, we showed that VRI-induced blood vessel loss in zebrafish represented a simple and effective in vivo model for studying vascular insufficiency and evaluating cancer drug vascular toxicities. - Highlights: • In vivo VRI model • Rescue effects of calycosin • Calycosin EC survival pathways.

  16. The inhibitor of calcium/calmodulin-dependent protein kinase II KN93 attenuates bone cancer pain via inhibition of KIF17/NR2B trafficking in mice.

    PubMed

    Liu, Yue; Liang, Ying; Hou, Bailing; Liu, Ming; Yang, Xuli; Liu, Chenglong; Zhang, Juan; Zhang, Wei; Ma, Zhengliang; Gu, Xiaoping

    2014-09-01

    The N-methyl-d-aspartate receptor (NMDAR) containing subunit 2B (NR2B) is critical for the regulation of nociception in bone cancer pain, although the precise molecular mechanisms remain unclear. KIF17, a kinesin motor, plays a key role in the dendritic transport of NR2B. The up-regulation of NR2B and KIF17 transcription results from an increase in phosphorylated cAMP-response element-binding protein (CREB), which is activated by calcium/calmodulin-dependent protein kinase II (CaMKII). In this study, we hypothesized that CaMKII-mediated KIF17/NR2B trafficking may contribute to bone cancer pain. Osteosarcoma cells were implanted into the intramedullary space of the right femurs of C3H/HeJ mice to induce progressive bone cancer-related pain behaviors. The expression of spinal t-CaMKII, p-CaMKII, NR2B and KIF17 after inoculation was also evaluated. These results showed that inoculation of osteosarcoma cells induced progressive bone cancer pain and resulted in a significant up-regulation of p-CaMKII, NR2B and KIF17 expression after inoculation. Intrathecal administration of KN93, a CaMKII inhibitor, down-regulated these three proteins and attenuated bone cancer pain in a dose- and time-dependent manner. These findings indicated that CaMKII-mediated KIF17/NR2B trafficking may contribute to bone cancer pain, and inhibition of CaMKII may be a useful alternative or adjunct therapy for relieving cancer pain.

  17. A signal-off sandwich photoelectrochemical immunosensor using TiO2 coupled with CdS as the photoactive matrix and copper (II) ion as inhibitor.

    PubMed

    Liu, Yixin; Li, Rongxia; Gao, Picheng; Zhang, Yong; Ma, Hongmin; Yang, Jiaojiao; Du, Bin; Wei, Qin

    2015-03-15

    In this work, a novel sandwich photoelectrochemical (PEC) biosensor was developed based on a signal-off strategy using TiO2 coupled with CdS quantum dots (QDs) as the photoactive matrix and copper (II) ion (Cu(2+)) as inhibitor. TiO2/CdS modified indium tin oxide (ITO) electrode was employed for primary antibody (Ab1) immobilization and the subsequent sandwich-type antibody-antigen (Ab-Ag) affinity interactions. Flower-like copper oxide (CuO) was used as labels of secondary antibody (Ab2) and immobilized on the modified electrode via specific affinity interactions between Ab2 and Ag. Cu(2+) was released by dissolving CuO with HCl, and then reacted with CdS to form CuxS (x=1, 2), which would create new energy levels for electron-hole recombination and resulted in a decrease of the photocurrent. CuO, as the labels of Ab2, was first applied in PEC biosensor based on the signal-off strategy of the Cu(2+) for CdS. Greatly enhanced sensitivity was achieved through the coupling of CdS QDs with TiO2. Besides, the introduction of polythiophene (PT-Cl) on the surface of TiO2 made the PEC signal more stable. Under 405nm irradiation at 0.1V, the PEC biosensor for H-IgG determination exhibited a linear range from 0.1pgmL(-1) to 100ngmL(-1) with a low detection limit of 0.03pgmL(-1). The proposed biosensor showed high sensitivity, stability and selectivity, which opens up a new promising signal-off PEC platform for future bioassay.

  18. Primary analysis of a phase II open-label trial of INCB039110, a selective JAK1 inhibitor, in patients with myelofibrosis.

    PubMed

    Mascarenhas, John O; Talpaz, Moshe; Gupta, Vikas; Foltz, Lynda M; Savona, Michael R; Paquette, Ronald; Turner, A Robert; Coughlin, Paul; Winton, Elliott; Burn, Timothy C; O'Neill, Peter; Clark, Jason; Hunter, Deborah; Assad, Albert; Hoffman, Ronald; Verstovsek, Srdan

    2017-02-01

    Combined Janus kinase 1 (JAK1) and JAK2 inhibition therapy effectively reduces splenomegaly and symptom burden related to myelofibrosis but is associated with dose-dependent anemia and thrombocytopenia. In this open-label phase II study, we evaluated the efficacy and safety of three dose levels of INCB039110, a potent and selective oral JAK1 inhibitor, in patients with intermediate- or high-risk myelofibrosis and a platelet count ≥50×10(9)/L. Of 10, 45, and 32 patients enrolled in the 100 mg twice-daily, 200 mg twice-daily, and 600 mg once-daily cohorts, respectively, 50.0%, 64.4%, and 68.8% completed week 24. A ≥50% reduction in total symptom score was achieved by 35.7% and 28.6% of patients in the 200 mg twice-daily cohort and 32.3% and 35.5% in the 600 mg once-daily cohort at week 12 (primary end point) and 24, respectively. By contrast, two patients (20%) in the 100 mg twice-daily cohort had ≥50% total symptom score reduction at weeks 12 and 24. For the 200 mg twice-daily and 600 mg once-daily cohorts, the median spleen volume reductions at week 12 were 14.2% and 17.4%, respectively. Furthermore, 21/39 (53.8%) patients who required red blood cell transfusions during the 12 weeks preceding treatment initiation achieved a ≥50% reduction in the number of red blood cell units transfused during study weeks 1-24. Only one patient discontinued for grade 3 thrombocytopenia. Non-hematologic adverse events were largely grade 1 or 2; the most common was fatigue. Treatment with INCB039110 resulted in clinically meaningful symptom relief, modest spleen volume reduction, and limited myelosuppression.

  19. Carbonic anhydrase inhibitors. Interaction of isozymes I, II, IV, V, and IX with phosphates, carbamoyl phosphate, and the phosphonate antiviral drug foscarnet.

    PubMed

    Rusconi, Stefano; Innocenti, Alessio; Vullo, Daniela; Mastrolorenzo, Antonio; Scozzafava, Andrea; Supuran, Claudiu T

    2004-12-06

    A detailed inhibition study of five carbonic anhydrase (CA, EC 4.2.1.1) isozymes with inorganic phosphates, carbamoyl phosphate, the antiviral phosphonate foscarnet as well as formate is reported. The cytosolic isozyme hCA I was weakly inhibited by neutral phosphate, strongly inhibited by carbamoyl phosphate (K(I) of 9.4 microM), and activated by hydrogen- and dihydrogenphosphate, foscarnet and formate (best activator foscarnet, K(A)=12 microM). The cytosolic isozyme hCA II was weakly inhibited by all the investigated anions, with carbamoyl phosphate showing a K(I) of 0.31 mM. The membrane-associated isozyme hCA IV was the most sensitive to inhibition by phosphates/phosphonates, showing a K(I) of 84 nM for PO(4)(3-), of 9.8 microM for HPO(4)(2-), and of 9.9 microM for carbamoyl phosphate. Foscarnet was the best inhibitor of this isozyme (K(I) of 0.82 mM) highly abundant in the kidneys, which may explain some of the renal side effects of the drug. The mitochondrial isozyme hCA V was weakly inhibited by all phosphates/phosphonates, except carbamoyl phosphate, which showed a K(I) of 8.5 microM. Thus, CA V cannot be the isozyme involved in the carbamoyl phosphate synthetase I biosynthetic reaction, as hypothesized earlier. Furthermore, the relative resistance of CA V to inhibition by inorganic phosphates suggests an evolutionary adaptation of this mitochondrial isozyme to the presence of high concentrations of such anions in these energy-converting organelles, where high amounts of ATP are produced by ATP synthetase, from ADP and inorganic phosphates. The transmembrane, tumor-associated isozyme hCA IX was on the other hand slightly inhibited by all these anions.

  20. Recognition and stabilization of a unique CPRI--structural motif in cucurbitaceae family trypsin inhibitor peptides: molecular dynamics based homology modeling using the X-ray structure of MCTI-II.

    PubMed

    Chakraborty, S; Haldar, U; Bera, A K; Pal, A K; Bhattacharya, S; Ghosh, S; Mukhopadhyay, B P; Banerjee, A

    2001-02-01

    The high resolution crystallographic structure of MCTI-II complexed with beta trypsin (PDB entry 1MCT) was used to model the corresponding structures of the six inhibitor peptides belonging to Cucurbitaceae family (MCTI-I, LA-1, LA-2, CMTI-I, CMTI-III, CMTI-IV). Two model inhibitors, LA-1 and LA-2 were refined by molecular dynamics to estimate the average solution structure. The difference accessible surface area (DASA) study of the inhibitors with and without trypsin revealed the Arginine and other residues of the inhibitors which bind to trypsin. The hydration dynamics study of LA1 and LA2 also confirm the suitability of water molecules at the active Arg site. Moreover, the presence of a unique 3D-structural motif comprises with the four CPRI residues from the amino terminal is thought to be conserved in all the six studied inhibitors, which seems essential for the directional fixation for proper complexation of the Arg (5) residue towards the trypsin S1-binding pocket. The role of the disulphide linkage in the geometrical stabilization of CPRI (Cysteine, Proline, Arginine, Isoleucine) motif has also been envisaged from the comparative higher intra molecular Cys (3) -Cys (20) disulphide dihedral energies.

  1. Synthesis and evaluation of malonate-based inhibitors of phosphosugar-metabolizing enzymes: class II fructose-1,6-bis-phosphate aldolases, type I phosphomannose isomerase, and phosphoglucose isomerase.

    PubMed

    Desvergnes, Stéphanie; Courtiol-Legourd, Stéphanie; Daher, Racha; Dabrowski, Maciej; Salmon, Laurent; Therisod, Michel

    2012-02-15

    In the design of inhibitors of phosphosugar metabolizing enzymes and receptors with therapeutic interest, malonate has been reported in a number of cases as a good and hydrolytically-stable surrogate of the phosphate group, since both functions are dianionic at physiological pH and of comparable size. We have investigated a series of malonate-based mimics of the best known phosphate inhibitors of class II (zinc) fructose-1,6-bis-phosphate aldolases (FBAs) (e.g., from Mycobacterium tuberculosis), type I (zinc) phosphomannose isomerase (PMI) from Escherichia coli, and phosphoglucose isomerase (PGI) from yeast. In the case of FBAs, replacement of one phosphate by one malonate on a bis-phosphorylated inhibitor (1) led to a new compound (4) still showing a strong inhibition (K(i) in the nM range) and class II versus class I selectivity (up to 8×10(4)). Replacement of the other phosphate however strongly affected binding efficiency and selectivity. In the case of PGI and PMI, 5-deoxy-5-malonate-D-arabinonohydroxamic acid (8) yielded a strong decrease in binding affinities when compared to its phosphorylated parent compound 5-phospho-D-arabinonohydroxamic acid (2). Analysis of the deposited 3D structures of the kinetically evaluated enzymes complexed to the phosphate-based inhibitors indicate that malonate could be a good phosphate surrogate only if phosphate is not tightly bound at the enzyme active site, such as in position 7 of compound 1 for FBAs. These observations are of importance for further design of inhibitors of phosphorylated-compounds metabolizing enzymes with therapeutic interest.

  2. Characterization and 2D NMR study of the stable [9-21, 15-27] 2 disulfide intermediate in the folding of the 3 disulfide trypsin inhibitor EETI II.

    PubMed Central

    Le-Nguyen, D.; Heitz, A.; Chiche, L.; el Hajji, M.; Castro, B.

    1993-01-01

    The three disulfide Ecballium elaterium trypsin inhibitor II (EETI II) reduction with dithiothreitol (DTT) and reoxidation of the fully reduced derivative have been examined. A common stable intermediate has been observed for both processes. Isolation and sequencing of carboxymethylated material showed that the intermediate lacks the [2-19] bridge. The NMR study showed a very strong structural conservation as compared to the native EETI II, suggesting that the bridges are the [9-21] and [15-27] native ones. The differences occurred in sections 2-7 (containing the free cysteine 2 and the Arg 4-Ile 5 active site) and 19-21 (containing the second free cysteine). Distance geometry calculations and restrained molecular dynamics refinements were also in favor of a [9-21, 15-27] arrangement and resulted in a well-conserved (7-28) segment. PMID:8443596

  3. A randomized multi-center phase II trial of the angiogenesis inhibitor Cilengitide (EMD 121974) and gemcitabine compared with gemcitabine alone in advanced unresectable pancreatic cancer

    PubMed Central

    Friess, Helmut; Langrehr, Jan M; Oettle, Helmut; Raedle, Jochen; Niedergethmann, Marco; Dittrich, Christian; Hossfeld, Dieter K; Stöger, Herbert; Neyns, Bart; Herzog, Peter; Piedbois, Pascal; Dobrowolski, Frank; Scheithauer, Werner; Hawkins, Robert; Katz, Frieder; Balcke, Peter; Vermorken, Jan; van Belle, Simon; Davidson, Neville; Esteve, Albert Abad; Castellano, Daniel; Kleeff, Jörg; Tempia-Caliera, Adrien A; Kovar, Andreas; Nippgen, Johannes

    2006-01-01

    Background Anti-angiogenic treatment is believed to have at least cystostatic effects in highly vascularized tumours like pancreatic cancer. In this study, the treatment effects of the angiogenesis inhibitor Cilengitide and gemcitabine were compared with gemcitabine alone in patients with advanced unresectable pancreatic cancer. Methods A multi-national, open-label, controlled, randomized, parallel-group, phase II pilot study was conducted in 20 centers in 7 countries. Cilengitide was administered at 600 mg/m2 twice weekly for 4 weeks per cycle and gemcitabine at 1000 mg/m2 for 3 weeks followed by a week of rest per cycle. The planned treatment period was 6 four-week cycles. The primary endpoint of the study was overall survival and the secondary endpoints were progression-free survival (PFS), response rate, quality of life (QoL), effects on biological markers of disease (CA 19.9) and angiogenesis (vascular endothelial growth factor and basic fibroblast growth factor), and safety. An ancillary study investigated the pharmacokinetics of both drugs in a subset of patients. Results Eighty-nine patients were randomized. The median overall survival was 6.7 months for Cilengitide and gemcitabine and 7.7 months for gemcitabine alone. The median PFS times were 3.6 months and 3.8 months, respectively. The overall response rates were 17% and 14%, and the tumor growth control rates were 54% and 56%, respectively. Changes in the levels of CA 19.9 went in line with the clinical course of the disease, but no apparent relationships were seen with the biological markers of angiogenesis. QoL and safety evaluations were comparable between treatment groups. Pharmacokinetic studies showed no influence of gemcitabine on the pharmacokinetic parameters of Cilengitide and vice versa. Conclusion There were no clinically important differences observed regarding efficacy, safety and QoL between the groups. The observations lay in the range of other clinical studies in this setting. The

  4. Clinical, molecular and immune analysis of dabrafenib and trametinib in metastatic melanoma patients that progressed on BRAF inhibitor monotherapy: a phase II clinical trial

    PubMed Central

    Chen, Guo; McQuade, Jennifer L.; Panka, David J.; Hudgens, Courtney W.; Amin-Mansour, Ali; Mu, Xinmeng Jasmine; Bahl, Samira; Jane-Valbuena, Judit; Wani, Khalida M.; Reuben, Alexandre; Creasy, Caitlyn A.; Jiang, Hong; Cooper, Zachary A.; Roszik, Jason; Bassett, Roland L.; Joon, Aron Y.; Simpson, Lauren M.; Mouton, Rosalind D.; Glitza, Isabella C.; Patel, Sapna P.; Hwu, Wen-Jen; Amaria, Rodabe N.; Diab, Adi; Hwu, Patrick; Lazar, Alexander J.; Wargo, Jennifer A.; Garraway, Levi A.; Tetzlaff, Michael T.; Sullivan, Ryan J.; Kim, Kevin B.; Davies, Michael A.

    2016-01-01

    Importance Combined treatment with dabrafenib and trametinib (CombiDT) achieves clinical responses in only ~15% of BRAF inhibitor (BRAFi)-refractory metastatic melanoma patients, in contrast to the high activity observed in BRAFi-naïve patients. Identifying correlates of response and mechanisms of resistance in this population will facilitate clinical management and rational therapeutic development. Objective To determine correlates of benefit from CombiDT therapy in BRAFi-refractory metastatic melanoma patients. Design Single-center, single-arm prospective phase II study of CombiDT in patients with BRAFV600 metastatic melanoma resistant to BRAFi monotherapy conducted between September 2012 and October 2014. Setting University of Texas MD Anderson Cancer Center. Participants 28 patients were screened and 23 enrolled. Key eligibility criteria included: BRAFV600 metastatic melanoma, prior BRAFi monotherapy, measurable disease (RECIST 1.1), and accessible tumor for biopsy. Intervention Patients were treated with dabrafenib (150 mg twice daily) and trametinib (2 mg daily) continuously until disease progression or intolerance. All participants underwent a mandatory baseline biopsy, and optional biopsies were performed on-treatment and at progression. Whole-exome sequencing, RT-PCR for BRAF splicing, RNAseq and IHC were performed on tumor samples, and blood was analyzed for levels of circulating BRAFV600. Main outcome measures Primary endpoint was overall response rate (ORR). Progression-free survival (PFS) and overall survival (OS) were secondary clinical endpoints. Results Among evaluable patients, the confirmed ORR was 10%, disease control rate (DCR) was 45%, and median PFS was 13 weeks. Clinical benefit was associated with duration of prior BRAFi >6 months (DCR 73% vs. 11% for ≤6 months, p=0.02) and decrease in circulating BRAFV600 at day 8 of cycle 1 (DCR 75% vs. 18% for no decrease, p=0.015), but not by pre-treatment MAPK pathway mutations or activation. On

  5. Discovery of Dihydrobenzoxazepinone (GS-6615) Late Sodium Current Inhibitor (Late INai), a Phase II Agent with Demonstrated Preclinical Anti-Ischemic and Antiarrhythmic Properties.

    PubMed

    Zablocki, Jeff A; Elzein, Elfatih; Li, Xiaofen; Koltun, Dmitry O; Parkhill, Eric Q; Kobayashi, Tetsuya; Martinez, Ruben; Corkey, Britton; Jiang, Haibo; Perry, Thao; Kalla, Rao; Notte, Gregory T; Saunders, Oliver; Graupe, Michael; Lu, Yafan; Venkataramani, Chandru; Guerrero, Juan; Perry, Jason; Osier, Mark; Strickley, Robert; Liu, Gongxin; Wang, Wei-Qun; Hu, Lufei; Li, Xiao-Jun; El-Bizri, Nesrine; Hirakawa, Ryoko; Kahlig, Kris; Xie, Cheng; Li, Cindy Hong; Dhalla, Arvinder K; Rajamani, Sridharan; Mollova, Nevena; Soohoo, Daniel; Lepist, Eve-Irene; Murray, Bernard; Rhodes, Gerry; Belardinelli, Luiz; Desai, Manoj C

    2016-10-03

    Late sodium current (late INa) is enhanced during ischemia by reactive oxygen species (ROS) modifying the Nav 1.5 channel, resulting in incomplete inactivation. Compound 4 (GS-6615, eleclazine) a novel, potent, and selective inhibitor of late INa, is currently in clinical development for treatment of long QT-3 syndrome (LQT-3), hypertrophic cardiomyopathy (HCM), and ventricular tachycardia-ventricular fibrillation (VT-VF). We will describe structure-activity relationship (SAR) leading to the discovery of 4 that is vastly improved from the first generation late INa inhibitor 1 (ranolazine). Compound 4 was 42 times more potent than 1 in reducing ischemic burden in vivo (S-T segment elevation, 15 min left anteriorior descending, LAD, occlusion in rabbits) with EC50 values of 190 and 8000 nM, respectively. Compound 4 represents a new class of potent late INa inhibitors that will be useful in delineating the role of inhibitors of this current in the treatment of patients.

  6. The effects of anti-DNA topoisomerase II drugs, etoposide and ellipticine, are modified in root meristem cells of Allium cepa by MG132, an inhibitor of 26S proteasomes.

    PubMed

    Żabka, Aneta; Winnicki, Konrad; Polit, Justyna Teresa; Maszewski, Janusz

    2015-11-01

    DNA topoisomerase II (Topo II), a highly specialized nuclear enzyme, resolves various entanglement problems concerning DNA that arise during chromatin remodeling, transcription, S-phase replication, meiotic recombination, chromosome condensation and segregation during mitosis. The genotoxic effects of two Topo II inhibitors known as potent anti-cancer drugs, etoposide (ETO) and ellipticine (EPC), were assayed in root apical meristem cells of Allium cepa. Despite various types of molecular interactions between these drugs and DNA-Topo II complexes at the chromatin level, which have a profound negative impact on the genome integrity (production of double-strand breaks, chromosomal bridges and constrictions, lagging fragments of chromosomes and their uneven segregation to daughter cell nuclei), most of the elicited changes were apparently similar, regarding both their intensity and time characteristics. No essential changes between ETO- and EPC-treated onion roots were noticed in the frequency of G1-, S-, G2-and M-phase cells, nuclear morphology, chromosome structures, tubulin-microtubule systems, extended distribution of mitosis-specific phosphorylation sites of histone H3, and the induction of apoptosis-like programmed cell death (AL-PCD). However, the important difference between the effects induced by the ETO and EPC concerns their catalytic activities in the presence of MG132 (proteasome inhibitor engaged in Topo II-mediated formation of cleavage complexes) and relates to the time-variable changes in chromosomal aberrations and AL-PCD rates. This result implies that proteasome-dependent mechanisms may contribute to the course of physiological effects generated by DNA lesions under conditions that affect the ability of plant cells to resolve topological problems that associated with the nuclear metabolic activities.

  7. In silico calculated affinity of FVIII-derived peptides for HLA class II alleles predicts inhibitor development in haemophilia A patients with missense mutations in the F8 gene.

    PubMed

    Pashov, A D; Calvez, T; Gilardin, L; Maillère, B; Repessé, Y; Oldenburg, J; Pavlova, A; Kaveri, S V; Lacroix-Desmazes, S

    2014-03-01

    Forty per cent of haemophilia A (HA) patients have missense mutations in the F8 gene. Yet, all patients with identical mutations are not at the same risk of developing factor VIII (FVIII) inhibitors. In severe HA patients, human leucocyte antigen (HLA) haplotype was identified as a risk factor for onset of FVIII inhibitors. We hypothesized that missense mutations in endogenous FVIII alter the affinity of the mutated peptides for HLA class II, thus skewing FVIII-specific T-cell tolerance and increasing the risk that the corresponding wild-type FVIII-derived peptides induce an anti-FVIII immune response during replacement therapy. Here, we investigated whether affinity for HLA class II of wild-type FVIII-derived peptides that correspond to missense mutations described in the Haemophilia A Mutation, Structure, Test and Resource database is associated with inhibitor development. We predicted the mean affinity for 10 major HLA class II alleles of wild-type FVIII-derived peptides that corresponded to 1456 reported cases of missense mutations. Linear regression analysis confirmed a significant association between the predicted mean peptide affinity and the mutation inhibitory status (P = 0.006). Significance was lost after adjustment on mutation position on FVIII domains. Although analysis of the A1-A2-A3-C1 domains yielded a positive correlation between predicted HLA-binding affinity and inhibitory status (OR = 0.29 [95% CI: 0.14-0.60] for the high affinity tertile, P = 0.002), the C2 domain-restricted analysis indicated an inverse correlation (OR = 3.56 [1.10-11.52], P = 0.03). Our data validate the importance of the affinity of FVIII peptides for HLA alleles to the immunogenicity of therapeutic FVIII in patients with missense mutations.

  8. PESTICINS II. I and II

    PubMed Central

    Brubaker, Robert R.; Surgalla, Michael J.

    1962-01-01

    Brubaker, Robert R. (Fort Detrick, Frederick, Md.) and Michael J. Surgalla. Pesticins. II. Production of pesticin I and II. J. Bacteriol. 84:539–545. 1962.—Pesticin I was separated from pesticin I inhibitor by ion-exchange chromatography of cell-free culture supernatant fluids and by acid precipitation of soluble preparations obtained from mechanically disrupted cells. The latter procedure resulted in formation of an insoluble pesticin I complex which, upon removal by centrifugation and subsequent dissolution in neutral buffer, exhibited a 100- to 1,000-fold increase in antibacterial activity over that originally observed. However, activity returned to the former level upon addition of the acid-soluble fraction, which contained pesticin I inhibitor. Since the presence of pesticin I inhibitor leads to serious errors in the determination of pesticin I, an assay medium containing ethylenediaminetetraacetic acid in excess Ca++ was developed; this medium eliminated the effect of the inhibitor. By use of the above medium, sufficient pesticin I was found to be contained within 500 nonirradiated cells to inhibit growth of a suitable indicator strain; at least 107 cells were required to effect a corresponding inhibition by pesticin II. Although both pesticins are located primarily within the cell during growth, pesticin I may arise extracellularly during storage of static cells. Slightly higher activity of pesticin I inhibitor was found in culture supernatant fluids than occurred in corresponding cell extracts of equal volume. The differences and similarities between pesticin I and some known bacteriocins are discussed. PMID:14016110

  9. Tetrahydroindazoles as Interleukin-2 Inducible T-Cell Kinase Inhibitors. Part II. Second-Generation Analogues with Enhanced Potency, Selectivity, and Pharmacodynamic Modulation in Vivo.

    PubMed

    Burch, Jason D; Barrett, Kathy; Chen, Yuan; DeVoss, Jason; Eigenbrot, Charles; Goldsmith, Richard; Ismaili, M Hicham A; Lau, Kevin; Lin, Zhonghua; Ortwine, Daniel F; Zarrin, Ali A; McEwan, Paul A; Barker, John J; Ellebrandt, Claire; Kordt, Daniel; Stein, Daniel B; Wang, Xiaolu; Chen, Yong; Hu, Baihua; Xu, Xiaofeng; Yuen, Po-Wai; Zhang, Yamin; Pei, Zhonghua

    2015-05-14

    The medicinal chemistry community has directed considerable efforts toward the discovery of selective inhibitors of interleukin-2 inducible T-cell kinase (ITK), given its role in T-cell signaling downstream of the T-cell receptor (TCR) and the implications of this target for inflammatory disorders such as asthma. We have previously disclosed a structure- and property-guided lead optimization effort which resulted in the discovery of a new series of tetrahydroindazole-containing selective ITK inhibitors. Herein we disclose further optimization of this series that resulted in further potency improvements, reduced off-target receptor binding liabilities, and reduced cytotoxicity. Specifically, we have identified a correlation between the basicity of solubilizing elements in the ITK inhibitors and off-target antiproliferative effects, which was exploited to reduce cytotoxicity while maintaining kinase selectivity. Optimized analogues were shown to reduce IL-2 and IL-13 production in vivo following oral or intraperitoneal dosing in mice.

  10. CGK733-induced LC3 II formation is positively associated with the expression of cyclin-dependent kinase inhibitor p21Waf1/Cip1 through modulation of the AMPK and PERK/CHOP signaling pathways.

    PubMed

    Wang, Yufeng; Kuramitsu, Yasuhiro; Baron, Byron; Kitagawa, Takao; Tokuda, Kazuhiro; Akada, Junko; Nakamura, Kazuyuki

    2015-11-24

    Microtubule-associated protein 1A/1B-light chain 3 (LC3)-II is essential for autophagosome formation and is widely used to monitor autophagic activity. We show that CGK733 induces LC3 II and LC3-puncta accumulation, which are not involved in the activation of autophagy. The treatment of CGK733 did not alter the autophagic flux and was unrelated to p62 degradation. Treatment with CGK733 activated the AMP-activated protein kinase (AMPK) and protein kinase RNA-like endoplasmic reticulum kinase/CCAAT-enhancer-binding protein homologous protein (PERK/CHOP) pathways and elevated the expression of p21Waf1/Cip1. Inhibition of both AMPK and PERK/CHOP pathways by siRNA or chemical inhibitor could block CGK733-induced p21Waf1/Cip1 expression as well as caspase-3 cleavage. Knockdown of LC3 B (but not LC3 A) abolished CGK733-triggered LC3 II accumulation and consequently diminished AMPK and PERK/CHOP activity as well as p21Waf1/Cip1 expression. Our results demonstrate that CGK733-triggered LC3 II formation is an initial event upstream of the AMPK and PERK/CHOP pathways, both of which control p21Waf1/Cip1 expression.

  11. Functional characterization and anti-cancer action of the clinical phase II cardiac Na+/K+ ATPase inhibitor istaroxime: in vitro and in vivo properties and cross talk with the membrane androgen receptor

    PubMed Central

    Alevizopoulos, Konstantinos; Dimas, Konstantinos; Papadopoulou, Natalia; Schmidt, Eva-Maria; Tsapara, Anna; Alkahtani, Saad; Honisch, Sabina; Prousis, Kyriakos C.; Alarifi, Saud; Calogeropoulou, Theodora

    2016-01-01

    Sodium potassium pump (Na+/K+ ATPase) is a validated pharmacological target for the treatment of various cardiac conditions. Recent published data with Na+/K+ ATPase inhibitors suggest a potent anti-cancer action of these agents in multiple indications. In the present study, we focus on istaroxime, a Na+/K+ ATPase inhibitor that has shown favorable safety and efficacy properties in cardiac phase II clinical trials. Our experiments in 22 cancer cell lines and in prostate tumors in vivo proved the strong anti-cancer action of this compound. Istaroxime induced apoptosis, affected the key proliferative and apoptotic mediators c-Myc and caspase-3 and modified actin cystoskeleton dynamics and RhoA activity in prostate cancer cells. Interestingly, istaroxime was capable of binding to mAR, a membrane receptor mediating rapid, non-genomic actions of steroids in prostate and other cells. These results support a multi-level action of Na+/K+ ATPase inhibitors in cancer cells and collectively validate istaroxime as a strong re-purposing candidate for further cancer drug development. PMID:27027435

  12. [Gender-related differences in the efficacy of treatment of hypertensive and coronary heart diseases in aged and elderly patients by angiotensin II receptor blockers and angiotensin converting enzyme inhibitors].

    PubMed

    Zaslavskaia, R M; Krivchikova, L V

    2013-01-01

    The aim of the work was to study hemodynamics and clinical symptoms before and after treatment of arterial hypertension (AH) and coronary heart disease (CHD) using angiotensin II receptor blockers and angiotensin converting enzyme inhibitors depending on the patients' sex. A total of 150 patients with AH and CHD were examined (80 women and 70 men, mean age 70 a 66 yr respectively). Eighty two of them (group 1) were given receptor blockers (losap, losartan, lorista, bloctran) and 63 (group 2) inhibitors (prestarium, noliprel). Effectiveness of treatment was evaluated from the results of 24-hr AP monitoring, daily self-control of AP (as described by Korotkov) and responds to questionnaires. The effectiveness of receptor blockers showed marked gender-specific differences. Specifically, they reduced systolic and diastolic pressure and improved well-being in women. In men, this treatment decreased the frequency of angina attacks, headache, and heart throbs. Enzyme inhibitors caused a greater reduction of diastolic AP in women but less pronounced gender-related changes in dynamics of main AP and ECG parameters than receptor blockers.

  13. Leuhistin, a new inhibitor of aminopeptidase M, produced by Bacillus laterosporus BMI156-14F1. II. Structure determination of leuhistin.

    PubMed

    Yoshida, S; Naganawa, H; Aoyagi, T; Takeuchi, T; Takeuchi, Y; Kodama, Y

    1991-06-01

    Leuhistin, a new inhibitor of aminopeptidase M, has been isolated from the culture broth of Bacillus laterosporus BMI156-14F1. The structure of leuhistin was determined by NMR studies. X-Ray and chemical analysis confirmed the absolute structure to be (2R,3S)-3-amino-2-hydroxy-2-(1H-imidazol-4-ylmethyl)-5-methylhe xanoic acid.

  14. Structure-activity relationships of β-hydroxyphosphonate nucleoside analogues as cytosolic 5'-nucleotidase II potential inhibitors: synthesis, in vitro evaluation and molecular modeling studies.

    PubMed

    Meurillon, Maïa; Marton, Zsuzsanna; Hospital, Audrey; Jordheim, Lars Petter; Béjaud, Jérôme; Lionne, Corinne; Dumontet, Charles; Périgaud, Christian; Chaloin, Laurent; Peyrottes, Suzanne

    2014-04-22

    The cytosolic 5'-nucleotidase II (cN-II) has been proposed as an attractive molecular target for the development of novel drugs circumventing resistance to cytotoxic nucleoside analogues currently used for treating leukemia and other malignant hemopathies. In the present work, synthesis of β-hydroxyphosphonate nucleoside analogues incorporating modifications either on the sugar residue or the nucleobase, and their in vitro evaluation towards the purified enzyme were carried out in order to determine their potency towards the inhibition of cN-II. In addition to the biochemical investigations, molecular modeling studies revealed important structural features for binding affinities towards the target enzyme.

  15. The remarkable efficiency of a Pin-II proteinase inhibitor sans two conserved disulfide bonds is due to enhanced flexibility and hydrogen bond density in the reactive site loop.

    PubMed

    Joshi, Rakesh S; Mishra, Manasi; Tamhane, Vaijayanti A; Ghosh, Anirban; Sonavane, Uddhavesh; Suresh, C G; Joshi, Rajendra; Gupta, Vidya S; Giri, Ashok P

    2014-01-01

    Capsicum annuum (L.) expresses diverse potato type II family proteinase inhibitors comprising of inhibitory repeat domain (IRD) as basic functional unit. Most IRDs contain eight conserved cysteines forming four disulfide bonds, which are indispensible for their stability and activity. We investigated the functional significance of evolutionary variations in IRDs and their role in mediating interaction between the inhibitor and cognate proteinase. Among the 18 IRDs encoded by C. annuum, IRD-7, -9, and -12 were selected for further characterization on the basis of variation in their reactive site loop, number of conserved cysteine residues, and higher theoretical ΔGbind for interaction with Helicoverpa armigera trypsin. Moreover, inhibition kinetics showed that IRD-9, despite loss of some of the disulfide bonds, was a more potent proteinase inhibitor among the three selected IRDs. Molecular dynamic simulations revealed that serine residues in the place of cysteines at seventh and eighth positions of IRD-9 resulted in an increase in the density of intramolecular hydrogen bonds and reactive site loop flexibility. Results of the serine residues chemical modification also supported this observation and provided a possible explanation for the remarkable inhibitory potential of IRD-9. Furthermore, this natural variant among IRDs showed special attributes like stability to proteolysis and synergistic inhibitory effect on other IRDs. It is likely that IRDs have coevolved selective specialization of their structure and function as a response towards specific insect proteases they encountered. Understanding the molecular mechanism of pest protease-plant proteinaceous inhibitor interaction will help in developing effective pest control strategies. An animated interactive 3D complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:JBSD:39.

  16. Phase I/II clinical trial of 2-difluoromethyl-ornithine (DFMO) and a novel polyamine transport inhibitor (MQT 1426) for feline oral squamous cell carcinoma.

    PubMed

    Skorupski, K A; O'Brien, T G; Guerrero, T; Rodriguez, C O; Burns, M R

    2011-12-01

    Polyamines are essential for cell proliferation. Their production is dysregulated in many cancers and polyamine depletion leads to tumour regression in mouse models of squamous cell carcinoma (SCC). The purpose of this study was to determine the maximally tolerated dose of the polyamine transport inhibitor, MQT 1426, when combined with the ornithine decarboxylase (ODC) inhibitor, DFMO, and to determine whether this therapy results in reduction in tumour polyamine levels. Thirteen cats with oral SCC received both drugs orally and serial tumour biopsies were obtained for polyamine measurement. Cats were monitored for response to therapy and toxicity. A maximum tolerated dose (MTD) of MQT 1426 when combined with DFMO was determined. Dose-limiting toxicity was vestibular in nature, but was fully reversible. Spermidine and total polyamine levels decreased significantly in tissues, two cats experienced objective tumour regression and six cats had stable disease. These results suggest that further study of polyamine depletion therapies is warranted.

  17. Phase II study of the PI3K inhibitor BKM120 in patients with advanced or recurrent endometrial carcinoma: a stratified type I-type II study from the GINECO group.

    PubMed

    Heudel, P-E; Fabbro, M; Roemer-Becuwe, C; Kaminsky, M C; Arnaud, A; Joly, F; Roche-Forestier, S; Meunier, J; Foa, C; You, B; Priou, F; Tazi, Y; Floquet, A; Selle, F; Berton-Rigaud, D; Lesoin, A; Kalbacher, E; Lortholary, A; Favier, L; Treilleux, I; Ray-Coquard, I

    2017-01-01

    Backround:Patients with metastatic endometrial carcinoma have a poor prognosis and PIK3CA mutations and amplifications are common in these cancers. This study evaluated the efficacy and safety of the pure PI3K inhibitor BKM120 in advanced or recurrent endometrial carcinoma.

  18. Kinetic analysis of a general model of activation of aspartic proteinase zymogens involving a reversible inhibitor. II. Contribution of the uni- and bimolecular activation routes.

    PubMed

    Muñoz-López, A; Sotos-Lomas, A; Arribas, E; Escribano, J; Masia-Perez, J; Muñoz-Muñoz, J L; Varon, R

    2007-04-01

    From the kinetic study carried out in part I of this series (preceding article) an analysis quantifying the relative contribution to the global process of the uni- and bimolecular routes has been carried out. This analysis suggests a way to predict the time course of the relative contribution as well as the effect on this relative weight of the initial zymogen, inhibitor and activating enzyme concentrations.

  19. Synthesis and Biological Evaluation of Pyrazolo[3,4-b]pyridin-4-ones as a New Class of Topoisomerase II Inhibitors.

    PubMed

    Tabrizi, Mojgan Aghazadeh; Baraldi, Pier Giovanni; Baraldi, Stefania; Prencipe, Filippo; Preti, Delia; Saponaro, Giulia; Romagnoli, Romeo; Gessi, Stefania; Merighi, Stefania; Stefanelli, Angela; Fazzi, Debora; Borea, Pier Andrea; Maia, Rodolfo Couto; Romeiro, Nelilma C; Fraga, Carlos A M; Barreiro, Eliezer J

    2015-01-01

    A series of 1,3,6-triphenylpyrazolo[3,4-b]pyridin-4-one derivatives was designed, synthesized and evaluated for cytotoxic activity in A375 human melanoma and human erythroleukemia (HEL) cells. The new pyrazolopyridones displayed comparable activities to the antitumor compound etoposide. The inhibitory effect of compounds 17, 18, 27 and 32 against topoisomerase II-mediated cleavage activities was measured finding good correlation with the results obtained from MTS assay. Docking studies into bacterial topoisomerase II (DNA Gyrase), topoisomerase IIα and topoisomerase IIβ binding sites in the DNA binding interface were performed.

  20. Louisianins A, B, C and D: non-steroidal growth inhibitors of testosterone-responsive SC 115 cells. II. Physico-chemical properties and structural elucidation.

    PubMed

    Takamatsu, S; Kim, Y P; Hayashi, M; Furuhata, K; Takayanagi, H; Komiyama, K; Woodruff, H B; Omura, S

    1995-10-01

    New non-steroidal growth inhibitors of testosterone-responsive SC 115 cells, louisianins A (MW: 189; C11H11NO2), B (MW: 191; C11H13NO2), C (MW: 173; C11H11NO) and D (MW: 173; C11H11NO) were isolated from the cultured broth of Streptomyces sp. WK-4028. Their structures were determined on the basis of spectroscopic data. The structure of louisianin A in particular was confirmed by X-ray crystallographic analysis. The four compounds commonly possess a unique pyrindine skeleton in the molecule.

  1. Phase II trial of the farnesyltransferase inhibitor tipifarnib plus fulvestrant in hormone receptor-positive metastatic breast cancer: New York Cancer Consortium Trial P6205

    PubMed Central

    Li, T.; Christos, P. J.; Sparano, J. A.; Hershman, D. L.; Hoschander, S.; O'Brien, K.; Wright, J. J.; Vahdat, L. T.

    2009-01-01

    Background: Fulvestrant produces a clinical benefit rate (CBR) of ∼45% in tamoxifen-resistant, hormone receptor (HR)-positive metastatic breast cancer (MBC) and 32% in aromatase inhibitor (AI)-resistant disease. The farnesyltransferase inhibitor tipifarnib inhibits Ras signaling and has preclinical and clinical activity in endocrine therapy-resistant disease. The objective of this study was to determine the efficacy and safety of tipifarnib–fulvestrant combination in HR-positive MBC. Patients and methods: Postmenopausal women with no prior chemotherapy for metastatic disease received i.m. fulvestrant 250 mg on day 1 plus oral tipifarnib 300 mg twice daily on days 1–21 every 28 days. The primary end point was CBR. Results: The CBR was 51.6% [95% confidence interval (CI) 34.0% to 69.2%] in 31 eligible patients and 47.6% (95% CI 26.3% to 69.0%) in 21 patients with AI-resistant disease. A futility analysis indicated that it was unlikely to achieve the prespecified 70% CBR. Tipifarnib dose modification was required in 8 of 33 treated patients (24%). Conclusions: The target CBR of 70% for the tipifarnib–fulvestrant combination in HR-positive MBC was set too high and was not achieved. The 48% CBR in AI-resistant disease compares favorably with the 32% CBR observed with fulvestrant alone in prior studies and merit further clinical and translational evaluation. PMID:19153124

  2. Combination of the histone deacetylase inhibitor depsipeptide and 5-fluorouracil upregulates major histocompatibility complex class II and p21 genes and activates caspase-3/7 in human colon cancer HCT-116 cells

    PubMed Central

    Okada, Kouji; Hakata, Shuko; Terashima, Jun; Gamou, Toshie; Habano, Wataru; Ozawa, Shogo

    2016-01-01

    Epigenetic anticancer drugs such as histone deacetylase (HDAC) inhibitors have been combined with existing anticancer drugs for synergistic or additive effects. In the present study, we found that a very low concentration of depsipeptide, an HDAC inhibitor, potentiated the antitumor activity of 5-fluorouracil (5-FU) in a human colon cancer cell model using HCT-116, HT29, and SW48 cells via the inhibition of colony formation ability or cellular viability. Exposure to a combination of 5-FU (1.75 µM) and 1 nM depsipeptide for 24 and 48 h resulted in a 3- to 4-fold increase in activated caspase-3/7, while 5-FU alone failed to activate caspase-3/7. Microarray and subsequent gene ontology analyses revealed that compared to 5-FU or depsipeptide alone, the combination treatment of 5-FU and depsipeptide upregulated genes related to cell death and the apoptotic process consistent with the inhibition of colony formation and caspase-3/7 activation. These analyses indicated marked upregulation of antigen processing and presentation of peptide or polysaccharide antigen via major histocompatibility complex (MHC) class (GO:0002504) and MHC protein complex (GO:0042611). Compared with vehicle controls, the cells treated with the combination of 5-FU and depsipeptide showed marked induction (3- to 8.5-fold) of expression of MHC class II genes, but not of MHC class I genes. Furthermore, our global analysis of gene expression, which was focused on genes involved in the molecular regulation of MHC class II genes, showed enhancement of pro-apoptotic PCAF and CIITA after the combination of 5-FU and depsipeptide. These results may indicate a closer relationship between elevation of MHC class II expression and cellular apoptosis induced by the combination of depsipeptide and 5-FU. To the best of our knowledge, this is the first study to report that the combination of 5-FU and depsipeptide induces human colon cancer cell apoptosis in a concerted manner with the induction of MHC class II gene

  3. 3-Nitropropionic Acid is a Suicide Inhibitor of MitochondrialRespiration that, Upon Oxidation by Complex II, Forms a Covalent AdductWith a Catalytic Base Arginine in the Active Site of the Enzyme

    SciTech Connect

    Huang, Li-shar; Sun, Gang; Cobessi, David; Wang, Andy C.; Shen,John T.; Tung, Eric Y.; Anderson, Vernon E.; Berry, Edward A.

    2005-12-01

    We report three new structures of mitochondrial respiratory Complex II (succinate ubiquinone oxidoreductase, E.C. 1.3.5.1) at up to 2.1 {angstrom} resolution, with various inhibitors. The structures define the conformation of the bound inhibitors and suggest the residues involved in substrate binding and catalysis at the dicarboxylate site. In particular they support the role of Arg297 as a general base catalyst accepting a proton in the dehydrogenation of succinate. The dicarboxylate ligand in oxaloacetate-containing crystals appears to be the same as that reported for Shewanella flavocytochrome c treated with fumarate. The plant and fungal toxin 3-nitropropionic acid, an irreversible inactivator of succinate dehydrogenase, forms a covalent adduct with the side chain of Arg297. The modification eliminates a trypsin cleavage site in the flavoprotein, and tandem mass spectroscopic analysis of the new fragment shows the mass of Arg 297 to be increased by 83 Da and to have potential of losing 44 Da, consistent with decarboxylation, during fragmentation.

  4. Synthesis and antiproliferative activity of 9-benzylamino-6-chloro-2-methoxy-acridine derivatives as potent DNA-binding ligands and topoisomerase II inhibitors.

    PubMed

    Zhang, Wei; Zhang, Bin; Zhang, Wei; Yang, Ti; Wang, Ning; Gao, Chunmei; Tan, Chunyan; Liu, Hongxia; Jiang, Yuyang

    2016-06-30

    A series of 9-benzylamino acridine derivatives were synthesized as an extension of our discovery of acridine antitumor agents. Most of these acridine compounds displayed good antiproliferative activity with IC50 values in low micromole range and structure-activity relationships were studied. Topo I- and II- mediated relaxation studies suggested that all of our compounds displayed strong Topo II inhibitory activity at 100 μM, while only four exhibited moderate Topo I inhibitory activity. The typical compound 8p could penetrate A549 cancer cells efficiently. Compound 8p could intercalate within the double-stranded DNA structure and induce DNA damage. Moreover, compound 8p could induce A549 cells apoptosis through caspase-dependent intrinsic pathway and arrest A549 cells at the G2/M phase.

  5. New derivatives of 11-methyl-6-[2-(dimethylamino)ethyl]-6H-indolo[2,3-b]quinoline as cytotoxic DNA topoisomerase II inhibitors.

    PubMed

    Luniewski, Wojciech; Wietrzyk, Joanna; Godlewska, Joanna; Switalska, Marta; Piskozub, Malgorzata; Peczynska-Czoch, Wanda; Kaczmarek, Lukasz

    2012-10-01

    Novel indolo[2,3-b]quinoline derivatives substituted at N-6 and C-2 or C-9 positions with (dimethylamino)ethyl chains linked to heteroaromatic core by ether, amide or amine bonds, were manufactured and evaluated in vitro for their cytotoxic activity against several cell lines of different origin including multidrug resistant sublines and tested for their ability to influence the cell cycle and inhibit topoisomerase II activity. It was found, that all compounds show cytotoxic activity against cell lines tested, including multidrug resistant LoVo/DX, MES-SA/DX5 and HL-60 sublines. The tested compounds induce the G(2)M phase cell cycle arrest in Jurkat cells, and inhibit topoisomerase II activity.

  6. Copper(II) complexes with highly water-soluble L- and D-proline-thiosemicarbazone conjugates as potential inhibitors of Topoisomerase IIα.

    PubMed

    Bacher, Felix; Enyedy, Éva A; Nagy, Nóra V; Rockenbauer, Antal; Bognár, Gabriella M; Trondl, Robert; Novak, Maria S; Klapproth, Erik; Kiss, Tamás; Arion, Vladimir B

    2013-08-05

    Two proline-thiosemicarbazone bioconjugates with excellent aqueous solubility, namely, 3-methyl-(S)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone [L-Pro-FTSC or (S)-H2L] and 3-methyl-(R)-pyrrolidine-2-carboxylate-2-formylpyridine thiosemicarbazone [D-Pro-FTSC or (R)-H2L], have been synthesized and characterized by elemental analysis, one- and two-dimensional (1)H and (13)C NMR spectroscopy, and electrospray ionization mass spectrometry. The complexation behavior of L-Pro-FTSC with copper(II) in an aqueous solution and in a 30% (w/w) dimethyl sulfoxide/water mixture has been studied via pH potentiometry, UV-vis spectrophotometry, electron paramagnetic resonance, (1)H NMR spectroscopy, and spectrofluorimetry. By the reaction of copper(II) acetate with (S)-H2L and (R)-H2L in water, the complexes [Cu(S,R)-L] and [Cu(R,S)-L] have been synthesized and comprehensively characterized. An X-ray diffraction study of [Cu(S,R)-L] showed the formation of a square-pyramidal complex, with the bioconjugate acting as a pentadentate ligand. Both copper(II) complexes displayed antiproliferative activity in CH1 ovarian carcinoma cells and inhibited Topoisomerase IIα activity in a DNA plasmid relaxation assay.

  7. In silico modification of Zn2+ binding group of suberoylanilide hydroxamic acid (SAHA) by organoselenium compounds as Homo sapiens class II HDAC inhibitor of cervical cancer

    NASA Astrophysics Data System (ADS)

    Sumo Friend Tambunan, Usman; Bakri, Ridla; Aditya Parikesit, Arli; Ariyani, Titin; Dyah Puspitasari, Ratih; Kerami, Djati

    2016-02-01

    Cervical cancer is the most common cancer in women, and ranks seventh of all cancers worldwide, with 529000 cases in 2008 and more than 85% cases occur in developing countries. One way to treat this cancer is through the inhibition of HDAC enzymes which play a strategic role in the regulation of gene expression. Suberoyl Anilide Hydroxamic Acid (SAHA) or Vorinostat is a drug which commercially available to treat the cancer, but still has some side effects. This research present in silico SAHA modification in Zinc Binding Group (ZBG) by organoselenium compound to get ligands which less side effect. From molecular docking simulation, and interaction analysis, there are five best ligands, namely CC27, HA27, HB28, IB25, and KA7. These five ligands have better binding affinity than the standards, and also have interaction with Zn2+ cofactor of inhibited HDAC enzymes. This research is expected to produce more potent HDAC inhibitor as novel drug for cervical cancer treatment.

  8. [Thromboxane synthetase inhibitors. II. Optical resolution of 4-[alpha-hydroxy-5-(1-imidazolyl)-2-methylbenzyl]-3,5-dimethylbenzo ic acid].

    PubMed

    Tsuruda, M; Shiotsuki, T; Matsumoto, T; Oe, T

    1989-01-01

    The optical resolution of racemic 4-[alpha-hydroxy-5-(1-imidazolyl)-2-methylbenzyl]-3,5-dimethylbenzoic acid (dl-I), a new potent and long lasting thromboxane synthetase inhibitor, was investigated. (S)-3-(3,5-Dinitrobenzoylthio)-2-methylpropionyl group was introduced to alpha-hydroxy moiety of methyl ester of dl-I by three steps of reaction to give the corresponding ester compound (VIa). Then, two diastereomers of VIa, alpha-VIa and beta-VIa, were separated by column chromatography using on silica gel. Alkaline hydrolysis of alpha-VIa and beta-VIa, followed by reactions with sodium ethylate gave optically pure sodium salts of (-)-I and (+)-I, respectively. The separative determination methods for the diastereomers of VIa, and for the enantiomers of the sodium salts of dl-I by high performance liquid chromatography were also established.

  9. The CDK inhibitor AT7519M in patients with relapsed or refractory chronic lymphocytic leukemia (CLL) and mantle cell lymphoma. A Phase II study of the Canadian Cancer Trials Group.

    PubMed

    Seftel, Matthew D; Kuruvilla, John; Kouroukis, Tom; Banerji, Versha; Fraser, Graeme; Crump, Michael; Kumar, Rajat; Chalchal, Haji I; Salim, Muhammad; Laister, Rob C; Crocker, Susan; Gibson, Spencer B; Toguchi, Marcia; Lyons, John F; Xu, Hao; Powers, Jean; Sederias, Joana; Seymour, Lesley; Hay, Annette E

    2017-06-01

    AT7519M is a small molecule inhibitor of cyclin-dependent kinases 1, 2, 4, 5, and 9 with in vitro activity against lymphoid malignancies. In two concurrent Phase II trials, we evaluated AT7519M in relapsed or refractory chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL) using the recommended Phase II dosing of 27 mg/m(2) twice weekly for 2 of every 3 weeks. Primary objective was objective response rate (ORR). Nineteen patients were accrued (7 CLL, 12 MCL). Four CLL patients achieved stable disease (SD). Two MCL patients achieved partial response (PR), and 6 had SD. One additional MCL patient with SD subsequently achieved PR 9 months after completion of AT7519M. Tumor lysis syndrome was not reported. In conclusion, AT7519M was safely administered to patients with relapsed/refractory CLL and MCL. In CLL, some patients had tumor reductions, but the ORR was low. In MCL, activity was noted with ORR of 27%.

  10. Phosphorylation of p53 on Ser15 during cell cycle caused by Topo I and Topo II inhibitors in relation to ATM and Chk2 activation

    PubMed Central

    Zhao, Hong; Traganos, Frank; Darzynkiewicz, Zbigniew

    2008-01-01

    The DNA topoisomerase I (topo1) inhibitor topotecan (TPT) and topo2 inhibitor mitoxantrone (MXT) damage DNA inducing formation of DNA double-strand breaks (DSBs). We have recently examined the kinetics of ATM and Chk2 activation as well as histone H2AX phosphorylation, the reporters of DNA damage, in individual human lung adenocarcinoma A549 cells treated with these drugs. Using a phospho-specific Ab to tumor suppressor protein p53 phosphorylated on Ser15 (p53-Ser15P) combined with an Ab that detects p53 regardless of the phosphorylation status and multiparameter cytometry we correlated the TPT- and MXT- induced p53-Ser15P with ATM and Chk2 activation as well as with H2AX phosphorylation in relation to the cell cycle phase. In untreated interphase cells, p53-Ser15P had “patchy” localization throughout the nucleoplasm while mitotic cells showed strong p53-Ser15P cytoplasmic immunofluorescence (IF). The intense phosphorylation of p53-Ser15, combined with activation of ATM and Chk2 (involving centrioles) as well as phosphorylation of H2AX seen in the untreated mitotic cells, suggest mobilization of the DNA damage detection/repair machinery in controlling cytokinesis. In the nuclei of cells treated with TPT or MXT, the expression of p53-Ser15P appeared as closely packed foci of intense IF. Following TPT treatment, the induction of p53-Ser15P was most pronounced in S-phase cells while no significant cell cycle phase differences were seen in cells treated with MXT. The maximal increase in p53-Ser15P expression, rising up to 2.5-fold above the level of its constitutive expression, was observed in cells treated with TPT or MXT for 4–6 h. This maximum expression of p53-Ser15P coincided in time with the peak of Chk2 activation but not with ATM activation and H2AX phosphorylation, both of which crested 1–2 h after the treatment with TPT or MXT. The respective kinetics of p53-Ser15 phosphorylation versus ATM and Chk2 activation suggest that in response to DNA damage by

  11. Biological evaluation of omega-(dialkylamino)alkyl derivatives of 6H-indolo[2,3-b]quinoline--novel cytotoxic DNA topoisomerase II inhibitors.

    PubMed

    Godlewska, Joanna; Luniewski, Wojciech; Zagrodzki, Bogdan; Kaczmarek, Lukasz; Bielawska-Pohl, Aleksandra; Dus, Danuta; Wietrzyk, Joanna; Opolski, Adam; Siwko, Magdalena; Jaromin, Anna; Jakubiak, Anna; Kozubek, Arkadiusz; Peczyñska-Czoch, Wanda

    2005-01-01

    A series of novel 6H-indolo[2,3-b]quinoline derivatives, substituted at C-2, C-9 or N-6 position with dialkyl(alkylamino)alkyl chains differing in the number of methylene groups, was prepared. These compounds were evaluated in vitro for their antimicrobial and cytotoxic activity against several cell lines of different origin and tested for their ability to influence the cell cycle and inhibit topoisomerase II activity. Liphophilic and calf thymus DNA-binding properties of these compounds were also investigated. All the compounds tested inhibited the growth of Gram-positive bacteria and fungi at MIC values ranging between 0.25 and 1 mM. They also showed cytotoxic activity against KB (human cervix carcinoma) cells (ID50 varied from 2.1 to 9.0 microM) and were able to overcome multidrug resistance in colorectal adenocarcinoma LoVo/DX, uterine sarcoma MES-SA/DX5 and promyelocytic leukemia HL-60/MX2 cells (the values of the resistance index RI fell between 0.54 and 2.4). The compounds induced G2M-phase cell cycle arrest in Jurkat T-cell leukemia cells, revealed DNA-binding properties and inhibited topoisomerase II activity.

  12. Economic evaluations of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in type 2 diabetic nephropathy: a systematic review

    PubMed Central

    2014-01-01

    Background Structured comparison of pharmacoeconomic analyses for ACEIs and ARBs in patients with type 2 diabetic nephropathy is still lacking. This review aims to systematically review the cost-effectiveness of both ACEIs and ARBs in type 2 diabetic patients with nephropathy. Methods A systematic literature search was performed in MEDLINE and EMBASE for the period from November 1, 1999 to Oct 31, 2011. Two reviewers independently assessed the quality of the articles included and extracted data. All cost-effectiveness results were converted to 2011 Euros. Results Up to October 2011, 434 articles were identified. After full-text checking and quality assessment, 30 articles were finally included in this review involving 39 study settings. All 6 ACEIs studies were literature-based evaluations which synthesized data from different sources. Other 33 studies were directed at ARBs and were designed based on specific trials. The Markov model was the most common decision analytic method used in the evaluations. From the cost-effectiveness results, 37 out of 39 studies indicated either ACEIs or ARBs were cost-saving comparing with placebo/conventional treatment, such as amlodipine. A lack of evidence was assessed for valid direct comparison of cost-effectiveness between ACEIs and ARBs. Conclusion There is a lack of direct comparisons of ACEIs and ARBs in existing economic evaluations. Considering the current evidence, both ACEIs and ARBs are likely cost-saving comparing with conventional therapy, excluding such RAAS inhibitors. PMID:24428868

  13. Phase II and Biomarker Study of the Dual MET/VEGFR2 Inhibitor Foretinib in Patients With Papillary Renal Cell Carcinoma

    PubMed Central

    Choueiri, Toni K.; Vaishampayan, Ulka; Rosenberg, Jonathan E.; Logan, Theodore F.; Harzstark, Andrea L.; Bukowski, Ronald M.; Rini, Brian I.; Srinivas, Sandy; Stein, Mark N.; Adams, Laurel M.; Ottesen, Lone H.; Laubscher, Kevin H.; Sherman, Laurie; McDermott, David F.; Haas, Naomi B.; Flaherty, Keith T.; Ross, Robert; Eisenberg, Peter; Meltzer, Paul S.; Merino, Maria J.; Bottaro, Donald P.; Linehan, W. Marston; Srinivasan, Ramaprasad

    2013-01-01

    Purpose Foretinib is an oral multikinase inhibitor targeting MET, VEGF, RON, AXL, and TIE-2 receptors. Activating mutations or amplifications in MET have been described in patients with papillary renal cell carcinoma (PRCC). We aimed to evaluate the efficacy and safety of foretinib in patients with PRCC. Patients and Methods Patients were enrolled onto the study in two cohorts with different dosing schedules of foretinib: cohort A, 240 mg once per day on days 1 through 5 every 14 days (intermittent arm); cohort B, 80 mg daily (daily dosing arm). Patients were stratified on the basis of MET pathway activation (germline or somatic MET mutation, MET [7q31] amplification, or gain of chromosome 7). The primary end point was overall response rate (ORR). Results Overall, 74 patients were enrolled, with 37 in each dosing cohort. ORR by Response Evaluation Criteria in Solid Tumors (RECIST) 1.0 was 13.5%, median progression-free survival was 9.3 months, and median overall survival was not reached. The presence of a germline MET mutation was highly predictive of a response (five of 10 v five of 57 patients with and without germline MET mutations, respectively). The most frequent adverse events of any grade associated with foretinib were fatigue, hypertension, gastrointestinal toxicities, and nonfatal pulmonary emboli. Conclusion Foretinib demonstrated activity in patients with advanced PRCC with a manageable toxicity profile and a high response rate in patients with germline MET mutations. PMID:23213094

  14. CRM1 Inhibition Sensitizes Drug Resistant Human Myeloma Cells to Topoisomerase II and Proteasome Inhibitors both In Vitro and Ex Vivo

    PubMed Central

    Turner, Joel G.; Dawson, Jana; Emmons, Michael F.; Cubitt, Christopher L.; Kauffman, Michael; Shacham, Sharon; Hazlehurst, Lori A.; Sullivan, Daniel M.

    2013-01-01

    Multiple myeloma (MM) remains an incurable disease despite improved treatments, including lenalidomide/pomalidomide and bortezomib/carfilzomib based therapies and high-dose chemotherapy with autologous stem cell rescue. New drug targets are needed to further improve treatment outcomes. Nuclear export of macromolecules is misregulated in many cancers, including in hematological malignancies such as MM. CRM1 (chromosome maintenance protein-1) is a ubiquitous protein that exports large proteins (>40 kDa) from the nucleus to the cytoplasm. We found that small-molecule Selective Inhibitors of Nuclear Export (SINE) prevent CRM1-mediated export of p53 and topoisomerase IIα (topo IIα). SINE's CRM1-inhibiting activity was verified by nuclear-cytoplasmic fractionation and immunocytochemical staining of the CRM1 cargoes p53 and topo IIα in MM cells. We found that SINE molecules reduced cell viability and induced apoptosis when used as both single agents in the sub-micromolar range and when combined with doxorubicin, bortezomib, or carfilzomib but not lenalidomide, melphalan, or dexamethasone. In addition, CRM1 inhibition sensitized MM cell lines and patient myeloma cells to doxorubicin, bortezomib, and carfilzomib but did not affect peripheral blood mononuclear or non-myeloma bone marrow mononuclear cells as shown by cell viability and apoptosis assay. Drug resistance induced by co-culture of myeloma cells with bone marrow stroma cells was circumvented by the addition of SINE molecules. These results support the continued development of SINE for patients with MM. PMID:24155773

  15. In vitro and in vivo metabolism of 14C-AZ11, a novel inhibitor of bacterial DNA gyrase/type II topoisomerase.

    PubMed

    Guo, Jian; Joubran, Camil; Luzietti, Ricardo A; Zhou, Fei; Basarab, Gregory S; Vishwanathan, Karthick

    2015-02-01

    1. (2R,4S,4aS)-11-Fluoro-2,4-dimethyl-8-((S)-4-methyl-2-oxooxazolidin-3-yl)-2,4,4a,6-tetrahydro-1H,1'H-spiro [isoxazolo[4,5-g][1,4]oxazino[4,3-a]quinoline-5,5'-pyrimidine]-2',4',6'(3'H)-trione (AZ11) is a novel mode-of-inhibition bacterial topoisomerase inhibitor that entered preclinical development for the treatment of Gram-positive bacteria infection. 2. The in vitro biotransformation studies of AZ11 using mouse, rat, dog and human hepatocytes showed low-intrinsic clearance in all species attributed to microsomal metabolism. 3. After a single intravenous administration of [14C]AZ11 in bile duct cannulated rats, the mean percentage of dose recovered in rat urine, bile and feces was approximately 18, 36 and 42%, respectively. Unchanged AZ11 recovered in rat urine and bile was less than 9% of the dose, indicating that AZ11 underwent extensive metabolism in rats. 4. The most abundant in vivo metabolite detected in urine and bile was M1 formed via ring opening on the piperidine and morpholine rings accounting for 20% of the administered dose. The major fecal metabolite was M5, which accounted for approximately 32% of administered dose. M5 was not formed when AZ11 incubated with rat intestinal microsomes and cytosol but was formed when incubated with fresh rat feces, suggesting that unchanged AZ11 was directly excreted into gut lumen where M5 formed as an intestinal microflora-mediated product. This process could have significant impact on bioavailability or exposure of AZ11 in rat.

  16. Post-marketing safety and effectiveness evaluation of the intravenous anti-influenza neuraminidase inhibitor peramivir. II: a pediatric drug use investigation.

    PubMed

    Komeda, Takuji; Ishii, Shingo; Itoh, Yumiko; Ariyasu, Yasuyuki; Sanekata, Masaki; Yoshikawa, Takayoshi; Shimada, Jingoro

    2015-03-01

    Peramivir is the only intravenous formulation among anti-influenza neuraminidase inhibitors currently available. Peramivir was approved for manufacturing and marketing in Japan in January 2010. In October 2010, an additional indication for pediatric use was approved. We conducted a pediatric drug use investigation of peramivir from October 2010 to February 2012 and evaluated its real-world safety and effectiveness in pediatric patients. We collected the data of 1254 peramivir-treated pediatric patients from 161 facilities across Japan and examined the safety in 1199 patients and effectiveness in 1188 patients. In total, 245 adverse events were observed with an incidence rate of 14.01% (168/1199). Of these, 115 events were adverse drug reactions (ADRs) with an incidence rate of 7.67% (92/1199). Common ADRs were diarrhea and abnormal behavior, with incidence rates of 2.50% (30/1199) and 2.25% (27/1199), respectively. Fourteen serious ADRs were observed in 12 patients (1.00%), including 5 cases each of abnormal behavior and neutrophil count decreased. While 87.0% (100 events) of ADRs occurred within 3 days after the initiation of peramivir administration, 87.8% (101 events) resolved or improved within 7 days after onset. Multivariate analyses indicated that the presence or absence of underlying diseases/complications was significantly related to ADR incidence. With regard to effectiveness, the median time to alleviation of both influenza symptoms and fever was 3 days, including the first day of administration. Thus, this study confirms the pediatric safety of peramivir without any concerns about effectiveness under routine clinical settings.

  17. Synthesis of 2-pyridyl-benzimidazole iridium(III), ruthenium(II), and platinum(II) complexes. study of the activity as inhibitors of amyloid-β aggregation and neurotoxicity evaluation.

    PubMed

    Yellol, Gorakh S; Yellol, Jyoti G; Kenche, Vijaya B; Liu, Xiang Ming; Barnham, Kevin J; Donaire, Antonio; Janiak, Christoph; Ruiz, José

    2015-01-20

    The design of small molecules that can target the aggregation of Aβ as potential therapeutic agents for Alzheimer's disease is an area of study that has attracted a lot of attention recently. The novel ligand methyl 1-butyl-2-pyridyl-benzimidazole carboxylate was prepared for the synthesis of a series of new iridium(III), ruthenium(II), and platinum(II) 2-pyridyl-benzimidazole complexes. The crystal structure of the half-sandwich iridium(III) complex was established by X-ray diffraction. An arrangement of two cationic complexes in the unit cell is observed, and it seems to be organized by weak π···π interactions that are taking place between two symmetry-related benzimidazole ring systems. All new compounds inhibited aggregation of Aβ1-42 in vitro as shown by both thioflavin T fluorescence assay and transmission electron microscopy. Among them the Ir compound rescued the toxicity of Aβ1-42 in primary cortical neurons effectively.

  18. New modulated design, docking and synthesis of carbohydrate-conjugate heterobimetallic CuII-SnIV complex as potential topoisomerase II inhibitor: in vitro DNA binding, cleavage and cytotoxicity against human cancer cell lines.

    PubMed

    Tabassum, Sartaj; Afzal, Mohd; Arjmand, Farukh

    2014-03-03

    New carbohydrate-conjugate heterobimetallic complexes [C₂₂H₅₀N₆O₁₃CuSnCl₂] (3) and [C₂₂H₅₈N₆O₁₇NiSnCl₂] (4) were synthesized from their monometallic analogs [C₂₂H₅₂N₆O₁₃Cu] (1) and [C₂₂H₆₀N₆O₁₇Ni] (2) containing N-glycoside ligand (L). In vitro DNA binding studies of L and complexes (1-4) with CT DNA were carried out by employing various biophysical and molecular docking techniques which revealed that heterobimetallic complex 3 strongly binds to DNA in comparison to 4, monometallic complexes (1 and 2) and the free ligand. Complex 3 cleaves pBR322 DNA via hydrolytic pathway (confirmed by T4 DNA ligase assay) and inhibited Topo-II activity in a dose-dependent manner. Furthermore, complex 3 was docked into the ATPase domain of human-Topo-II in order to probe the possible mechanism of inhibition.

  19. Randomized Phase Ib/II Study of Gemcitabine Plus Placebo or Vismodegib, a Hedgehog Pathway Inhibitor, in Patients With Metastatic Pancreatic Cancer

    PubMed Central

    Catenacci, Daniel V.T.; Junttila, Melissa R.; Karrison, Theodore; Bahary, Nathan; Horiba, Margit N.; Nattam, Sreenivasa R.; Marsh, Robert; Wallace, James; Kozloff, Mark; Rajdev, Lakshmi; Cohen, Deirdre; Wade, James; Sleckman, Bethany; Lenz, Heinz-Josef; Stiff, Patrick; Kumar, Pankaj; Xu, Peng; Henderson, Les; Takebe, Naoko; Salgia, Ravi; Wang, Xi; Stadler, Walter M.; de Sauvage, Frederic J.; Kindler, Hedy L.

    2015-01-01

    Purpose Sonic hedgehog (SHH), an activating ligand of smoothened (SMO), is overexpressed in > 70% of pancreatic cancers (PCs). We investigated the impact of vismodegib, an SHH antagonist, plus gemcitabine (GV) or gemcitabine plus placebo (GP) in a multicenter phase Ib/randomized phase II trial and preclinical PC models. Patients and Methods Patients with PC not amenable to curative therapy who had received no prior therapy for metastatic disease and had Karnofsky performance score ≥ 80 were enrolled. Patients were randomly assigned in a one-to-one ratio to GV or GP. The primary end point was progression-free-survival (PFS). Exploratory correlative studies included serial SHH serum levels and contrast perfusion computed tomography imaging. To further investigate putative biologic mechanisms of SMO inhibition, two autochthonous pancreatic cancer models (KrasG12D; p16/p19fl/fl; Pdx1-Cre and KrasG12D; p53R270H/wt; Pdx1-Cre) were studied. Results No safety issues were identified in the phase Ib portion (n = 7), and the phase II study enrolled 106 evaluable patients (n = 53 in each arm). Median PFS was 4.0 and 2.5 months for GV and GP arms, respectively (95% CI, 2.5 to 5.3 and 1.9 to 3.8, respectively; adjusted hazard ratio, 0.81; 95% CI, 0.54 to 1.21; P = .30). Median overall survival (OS) was 6.9 and 6.1 months for GV and GP arms, respectively (95% CI, 5.8 to 8.0 and 5.0 to 8.0, respectively; adjusted hazard ratio, 1.04; 95% CI, 0.69 to 1.58; P = .84). Response rates were not significantly different. There were no significant associations between correlative markers and overall response rate, PFS, or OS. Preclinical trials revealed no significant differences with vismodegib in drug delivery, tumor growth rate, or OS in either model. Conclusion The addition of vismodegib to gemcitabine in an unselected cohort did not improve overall response rate, PFS, or OS in patients with metastatic PC. Our preclinical and clinical results revealed no statistically significant

  20. Angiogenesis Inhibitors

    MedlinePlus

    ... inhibitors: current strategies and future prospects. CA: A Cancer Journal for Clinicians 2010; 60(4):222–243. [PubMed Abstract] Chen HX, Cleck JN. Adverse effects of anticancer agents that target the VEGF pathway. Nature Reviews Clinical Oncology 2009; 6(8):465– ...

  1. Carboxylesterase inhibitors

    PubMed Central

    Hatfield, M. Jason; Potter, Philip M.

    2011-01-01

    Introduction Carboxylesterases play major roles in the hydrolysis of numerous therapeutically active compounds. This is, in part, due to the prevalence of the ester moiety in these small molecules. However, the impact these enzymes may play on drug stability and pharmacokinetics is rarely considered prior to molecule development. Therefore, the application of selective inhibitors of this class of proteins may have utility in modulating the metabolism, distribution and toxicity of agents that are subjected to enzyme hydrolysis. Areas covered This review details the development of all such compounds dating back to 1986, but principally focuses on the very recent identification of selective human carboxylesterases inhibitors. Expert opinion The implementation of carboxylesterase inhibitors may significantly revolutionize drug discovery. Such molecules may allow for improved efficacy of compounds inactivated by this class of enzymes and/or reduce the toxicity of agents that are activated by these proteins. Furthermore, since lack of carboxylesterase activity appears to have no obvious biological consequence, these compounds could be applied in combination with virtually any esterified drug. Therefore, inhibitors of these proteins may have utility in altering drug hydrolysis and distribution in vivo. The characteristics, chemical and biological properties, and potential uses of such agents, are discussed here. PMID:21609191

  2. A prospective phase I-II trial of the cyclooxygenase-2 inhibitor celecoxib in patients with carcinoma of the cervix with biomarker assessment of the tumor microenvironment

    SciTech Connect

    Herrera, Fernanda G.; Chan, Philip; Doll, Corinne; Milosevic, Michael; Oza, Amit; Syed, Amy; Pintilie, Melania; Levin, Wilfred; Manchul, Lee; Fyles, Anthony . E-mail: Anthony.Fyles@rmp.uhn.on.ca

    2007-01-01

    Purpose: To evaluate the toxicity and effectiveness of celecoxib in combination with definitive chemoradiotherapy (CRT) in women with locally advanced cervical cancer. Methods and Materials: Thirty-one patients were accrued to a phase I-II trial of celecoxib 400 mg by mouth twice per day for 2 weeks before and during CRT. Tumor oxygenation (HP{sub 5}) and interstitial fluid pressure (IFP) were measured before and 2 weeks after celecoxib administration alone. The median follow-up time was 2.7 years (range, 1.1-4.4 years). Results: The most common acute G3/4 toxicities were hematologic (4/31, 12.9%) and gastrointestinal (5/31, 16.1%) largely attributed to chemotherapy. Late G3/4 toxicity was seen in 4 of 31 patients (13.7% actuarial risk at 2 yr), including fistulas in 3 patients (9.7%). Within the first year of follow-up, 25 of 31 patients (81%) achieved complete response (CR), of whom 20 remained in CR at last follow-up. After 2 weeks of celecoxib administration before CRT, the median IFP decreased slightly (median absolute, -4.6 mm Hg; p = 0.09; relative, -21%; p = 0.07), whereas HP{sub 5} did not change significantly (absolute increase, 3.6%; p = 0.51; median relative increase, 11%; p = 0.27). No significant associations were seen between changes in HP{sub 5} or IFP and response to treatment (p = 0.2, relative HP{sub 5} change and p = 0.14, relative IFP change). Conclusions: Celecoxib in combination with definitive CRT is associated with acceptable acute toxicity, but higher than expected late complications. Celecoxib is associated with a modest reduction in the angiogenic biomarker IFP, but this does not correspond with tumor response.

  3. AT-33A PHASE II STUDY OF CONCURRENT RADIATION THERAPY, TEMOZOLOMIDE AND THE HISTONE DEACETYLASE INHIBITOR VALPROIC ACID FOR PATIENTS WITH GLIOBLASTOMA MULTIFORME

    PubMed Central

    Krauze, Andra V.; Myrehaug, Sten D.; Chang, Michael G.; Holdford, Diane J.; Smith, Sharon; Shih, Joanna; Tofilon, Peter; Fine, Howard; Camphausen, Kevin A.

    2014-01-01

    BACKGROUND: Glioblastoma (GBM) remains an aggressive brain tumor with poor prognosis. Valproic acid (VPA) is an antiepileptic agent that has been shown to have HDACi activity and to radiosensitize GBM cells in preclinical models. This phase II study aimed to determine if the addition of VPA to standard radiation therapy and temozolomide would improve OS and PFS. METHODS: We prospectively assessed survival, radiological and clinical progression in 37 newly diagnosed glioblastoma patients with the administration of VPA at 25 mg/kg orally BID concurrent with radiation therapy (RT) and temozolomide (TMZ). The first dose of VPA was given 1 week before the first day of RT at 10 to 15 mg/kg/day and subsequently tapered up to 25 mg/kg/day over the week prior to radiation. RESULTS: 81% of patients took VPA according to protocol. Median OS was 29.6 months (21- 63.8), median PFS was 10.5 (6.8 - 51.2). OS at 6, 12, 24 months was 97%, 86%, 56% respectively. PFS at 6, 12, 24 months was 70%, 43%, 38% respectively. The most common grade 3 or 4 toxicities of VPA in conjunction with TMZ were blood/ bone marrow toxicity (32%), neurological (11%), metabolic/laboratory (8%). At the end of the study 26 (70%) patients were dead, 7 were live without disease, 4 alive with disease. Younger age (<= 50 years) compared to older age and class V RPA were significant for both OS and PFS. Using a landmark analysis, an early progression was related to a shorter interval between progression and death, whereas, a later progression was related to a longer interval between progression and death (p = 0.0002) HR 4.7. CONCLUSION: The addition of VPA to concurrent RT and TMZ in the treatment of newly diagnosed GBM may result in superior outcomes as compared to contemporary and historical data and merits further study.

  4. Changes in DNA methylation and transgenerational mobilization of a transposable element (mPing) by the Topoisomerase II inhibitor, Etoposide, in rice

    PubMed Central

    2012-01-01

    Background Etoposide (epipodophyllotoxin) is a chemical commonly used as an anti-cancer drug which inhibits DNA synthesis by blocking topoisomerase II activity. Previous studies in animal cells have demonstrated that etoposide constitutes a genotoxic stress which may induce genomic instability including mobilization of normally quiescent transposable elements (TEs). However, it remained unknown whether similar genetically mutagenic effects could be imposed by etoposide in plant cells. Also, no information is available with regard to whether the drug may cause a perturbation of epigenetic stability in any organism. Results To investigate whether etoposide could generate genetic and/or epigenetic instability in plant cells, we applied etoposide to germinating seeds of six cultivated rice (Oryza sativa L.) genotypes including both subspecies, japonica and indica. Based on the methylation-sensitive gel-blotting results, epigenetic changes in DNA methylation of three TEs (Tos17, Osr23 and Osr36) and two protein-encoding genes (Homeobox and CDPK-related genes) were detected in the etoposide-treated plants (S0 generation) in four of the six studied japonica cultivars, Nipponbare, RZ1, RZ2, and RZ35, but not in the rest japonica cultivar (Matsumae) and the indica cultivar (93-11). DNA methylation changes in the etoposide-treated S0 rice plants were validated by bisulfite sequencing at both of two analyzed loci (Tos17 and Osr36). Transpositional activity was tested for eight TEs endogenous to the rice genome in both the S0 plants and their selfed progenies (S1 and S2) of one of the cultivars, RZ1, which manifested heritable phenotypic variations. Results indicated that no transposition occurred in the etoposide-treated S0 plants for any of the TEs. Nonetheless, a MITE transposon, mPing, showed rampant mobilization in the S1 and S2 progenies descended from the drug-treated S0 plants. Conclusions Our results demonstrate that etoposide imposes a similar genotoxic stress on

  5. 1-[N, O-bis-(5-isoquinolinesulphonyl)-N-methyl-L-tyrosyl]-4- phenylpiperazine (KN-62), an inhibitor of calcium-dependent camodulin protein kinase II, inhibits both insulin- and hypoxia-stimulated glucose transport in skeletal muscle.

    PubMed Central

    Brozinick, J T; Reynolds, T H; Dean, D; Cartee, G; Cushman, S W

    1999-01-01

    Previous studies have indicated a role for calmodulin in hypoxia-and insulin-stimulated glucose transport. However, since calmodulin interacts with multiple protein targets, it is unknown which of these targets is involved in the regulation of glucose transport. In the present study, we have used the calcium-dependent calmodulin protein kinase II (CAMKII) inhibitor 1-[N, O-bis-(5-isoquinolinesulphonyl) -N-methyl-L-tyrosyl]-4-phenylpiperazine (KN-62) to investigate the possible role of this enzyme in the regulation of glucose transport in isolated rat soleus and epitrochlearis muscles. KN-62 did not affect basal 2-deoxyglucose transport, but it did inhibit both insulin- and hypoxia-stimulated glucose transport activity by 46 and 40% respectively. 1-[N,O-Bis-(1, 5-isoquinolinesulphonyl)-N-methyl-l-tyrosyl]-4-phenylpiperazine (KN-04), a structural analogue of KN-62 that does not inhibit CAMKII, had no effect on hypoxia-or insulin-stimulated glucose transport. Accordingly, KN-62 decreased the stimulated cell-surface GLUT4 labelling by a similar extent as the inhibition of glucose transport (insulin, 49% and hypoxia, 54%). Additional experiments showed that KN-62 also inhibited insulin- and hypoxia-stimulated transport by 37 and 40% respectively in isolated rat epitrochlearis (a fast-twitch muscle), indicating that the effect of KN-62 was not limited to the slow-twitch fibres of the soleus. The inhibitory effect of KN-62 on hypoxia-stimulated glucose transport appears to be specific to CAMKII, since KN-62 did not inhibit hypoxia-stimulated 45Ca efflux from muscles pre-loaded with 45Ca, or hypoxia-stimulated glycogen breakdown. Additionally, KN-62 affected neither insulin-stimulated phosphoinositide 3-kinase nor Akt activity, suggesting that the effects of KN-62 are not due to non-specific effects of this inhibitor on these regions of the insulin-signalling cascade. The results of the present study suggest that CAMKII might have a distinct role in insulin- and hypoxia

  6. Targeting HER2 aberrations as actionable drivers in lung cancers: phase II trial of the pan-HER tyrosine kinase inhibitor dacomitinib in patients with HER2-mutant or amplified tumors

    PubMed Central

    Kris, M. G.; Camidge, D. R.; Giaccone, G.; Hida, T.; Li, B. T.; O'Connell, J.; Taylor, I.; Zhang, H.; Arcila, M. E.; Goldberg, Z.; Jänne, P. A.

    2015-01-01

    Background HER2 mutations and amplifications have been identified as oncogenic drivers in lung cancers. Dacomitinib, an irreversible inhibitor of HER2, EGFR (HER1), and HER4 tyrosine kinases, has demonstrated activity in cell-line models with HER2 exon 20 insertions or amplifications. Here, we studied dacomitinib in patients with HER2-mutant or amplified lung cancers. Patients and methods As a prespecified cohort of a phase II study, we included patients with stage IIIB/IV lung cancers with HER2 mutations or amplification. We gave oral dacomitinib at 30–45 mg daily in 28-day cycles. End points included partial response rate, overall survival, and toxicity. Results We enrolled 30 patients with HER2-mutant (n = 26, all in exon 20 including 25 insertions and 1 missense mutation) or HER2-amplified lung cancers (n = 4). Three of 26 patients with tumors harboring HER2 exon 20 mutations [12%; 95% confidence interval (CI) 2% to 30%] had partial responses lasting 3+, 11, and 14 months. No partial responses occurred in four patients with tumors with HER2 amplifications. The median overall survival was 9 months from the start of dacomitinib (95% CI 7–21 months) for patients with HER2 mutations and ranged from 5 to 22 months with amplifications. Treatment-related toxicities included diarrhea (90%; grade 3/4: 20%/3%), dermatitis (73%; grade 3/4: 3%/0%), and fatigue (57%; grade 3/4: 3%/0%). One patient died on study likely due to an interaction of dacomitinib with mirtazapine. Conclusions Dacomitinib produced objective responses in patients with lung cancers with specific HER2 exon 20 insertions. This observation validates HER2 exon 20 insertions as actionable targets and justifies further study of HER2-targeted agents in specific HER2-driven lung cancers. ClinicalTrials.gov NCT00818441. PMID:25899785

  7. Design and synthesis of isoform-selective phospholipase D (PLD) inhibitors. Part II. Identification of the 1,3,8-triazaspiro[4,5]decan-4-one privileged structure that engenders PLD2 selectivity.

    PubMed

    Lavieri, Robert; Scott, Sarah A; Lewis, Jana A; Selvy, Paige E; Armstrong, Michelle D; Alex Brown, H; Lindsley, Craig W

    2009-04-15

    This Letter describes the synthesis and structure-activity relationships (SAR) of isoform-selective PLD inhibitors. By virtue of the installation of a 1,3,8-triazaspiro[4,5]decan-4-one privileged structure, PLD inhibitors with nanomolar potency and an unprecedented 40-fold selectivity for PLD2 over PLD1 were developed. Interestingly, SAR for this diverged from our earlier efforts, and dual PLD1/2 inhibitors were also discovered within this series.

  8. 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.

  9. Azidoblebbistatin, a photoreactive myosin inhibitor

    PubMed Central

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

    2012-01-01

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

  10. Towards a green hydrate inhibitor: imaging antifreeze proteins on clathrates.

    PubMed

    Gordienko, Raimond; Ohno, Hiroshi; Singh, Vinay K; Jia, Zongchao; Ripmeester, John A; Walker, Virginia K

    2010-02-11

    The formation of hydrate plugs in oil and gas pipelines is a serious industrial problem and recently there has been an increased interest in the use of alternative hydrate inhibitors as substitutes for thermodynamic inhibitors like methanol. We show here that antifreeze proteins (AFPs) possess the ability to modify structure II (sII) tetrahydrofuran (THF) hydrate crystal morphologies by adhering to the hydrate surface and inhibiting growth in a similar fashion to the kinetic inhibitor poly-N-vinylpyrrolidone (PVP). The effects of AFPs on the formation and growth rate of high-pressure sII gas mix hydrate demonstrated that AFPs are superior hydrate inhibitors compared to PVP. These results indicate that AFPs may be suitable for the study of new inhibitor systems and represent an important step towards the development of biologically-based hydrate inhibitors.

  11. Towards a Green Hydrate Inhibitor: Imaging Antifreeze Proteins on Clathrates

    PubMed Central

    Gordienko, Raimond; Ohno, Hiroshi; Singh, Vinay K.; Jia, Zongchao; Ripmeester, John A.; Walker, Virginia K.

    2010-01-01

    The formation of hydrate plugs in oil and gas pipelines is a serious industrial problem and recently there has been an increased interest in the use of alternative hydrate inhibitors as substitutes for thermodynamic inhibitors like methanol. We show here that antifreeze proteins (AFPs) possess the ability to modify structure II (sII) tetrahydrofuran (THF) hydrate crystal morphologies by adhering to the hydrate surface and inhibiting growth in a similar fashion to the kinetic inhibitor poly-N-vinylpyrrolidone (PVP). The effects of AFPs on the formation and growth rate of high-pressure sII gas mix hydrate demonstrated that AFPs are superior hydrate inhibitors compared to PVP. These results indicate that AFPs may be suitable for the study of new inhibitor systems and represent an important step towards the development of biologically-based hydrate inhibitors. PMID:20161789

  12. Non-target-site resistance to ALS inhibitors in waterhemp (Amaranthus tuberculatus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A waterhemp population (MCR) previously characterized as resistant to 4-hyroxyphenylpyruvate dioxygenase (HPPD) and photosystem II (PSII) inhibitors was found to have two different resistance responses to acetolactate synthase (ALS) inhibitors. Plants from the MCR population exhibiting high resistan...

  13. Seminal and colostral protease inhibitors on leukocytes.

    PubMed

    Veselský, L; Cechová, D; Hruban, V; Klaudy, J

    1982-01-01

    For detection of protease inhibitors from cow colostrum (CTI) and bull seminal plasma (BUSI I and BUSI II) on the surface of leukocytes, immunological methods were used. An agglutination and an immunofluorescence test demonstrated components on the surface of bovine, porcine and ovine granulocytes and lymphocytes which were immunologically identical with the protease inhibitors isolated from cow colostrum and bull seminal plasma. When antisera against (CTI, BUSI and BUSI II were absorbed by bovine and porcine liver, kidney and spleen homogenate or by bovine and porcine granulocytes or lymphocytes, the immunological tests were negative.

  14. Regulation of the activity of protein kinases by endogenous heat stable protein inhibitors.

    PubMed

    Szmigielski, A

    1985-01-01

    Protein kinase activities are regulated by endogenous thermostable protein inhibitors. Type I inhibitor is a protein of MW 22,000-24,000 which inhibits specifically cyclic AMP-(cAMP) dependent protein kinase (APK) as a competitive inhibitor of catalytic subunits of the enzyme. Type I inhibitor activity changes inversely according to the activation of adenylate cyclase and the changes in cAMP content in tissues. It seems that type I inhibitor serves as a factor preventing spontaneous cAMP-dependent phosphorylation in unstimulated cell. The other thermostable protein which inhibits APK activity has been found in Sertoli cell-enriched testis (testis inhibitor). Physiological role of the testis inhibitor is unknown. Type II inhibitor is a protein of MW 15,000 which blocks phosphorylation mediated by cAMP and cyclic GMP (cGMP) dependent (APK and GPK) and cyclic nucleotide independent protein kinases as a competitive inhibitor of substrate proteins. Activity of this inhibitor specifically changes in reciprocal manner to the changes in cGMP content. It seems that type II inhibitor serves as a factor preventing the phosphorylation catalyzed by GPK when cGMP content is low. Stimulation of guanylate cyclase and activation of GPK is followed by a decrease of type II inhibitor activity. This change in relationship between activities of GPK and type II inhibitor allows for effective phosphorylation catalyzed by this enzyme when cGMP content is increased.

  15. Interfacial inhibitors of protein-nucleic acid interactions.

    PubMed

    Pommier, Yves; Marchand, Christophe

    2005-07-01

    This essay develops the paradigm of "Interfacial Inhibitors" (Pommier and Cherfils, TiPS, 2005, 28: 136) for inhibitory drugs beside orthosteric (competitive or non-competitive) and allosteric inhibitors. Interfacial inhibitors bind with high selectivity to a binding site involving two or more macromolecules within macromolecular complexes undergoing conformational changes. Interfacial binding traps (generally reversibly) a transition state of the complex, resulting in kinetic inactivation. The exemplary case of interfacial inhibitor of protein-DNA interface is camptothecin and its clinical derivatives. We will also provide examples generalizing the interfacial inhibitor concept to inhibitors of topoisomerase II (anthracyclines, ellipticines, epipodophyllotoxins), gyrase (quinolones, ciprofloxacin, norfloxacin), RNA polymerases (alpha-amanitin and actinomycin D), and ribosomes (antibiotics such as streptomycin, hygromycin B, tetracycline, kirromycin, fusidic acid, thiostrepton, and possibly cycloheximide). We discuss the implications of the interfacial inhibitor concept for drug discovery.

  16. Proton pump inhibitors

    MedlinePlus

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

  17. [Pharmacokinetics of sodium 4-[alpha-hydroxy-5-(1-imidazolyl)-2-methylbenzyl]-3,5-dimethylbenzoate (Y-20811), a new thromboxane synthetase inhibitor. II. Pharmacokinetics of intact drug and main metabolite in dog].

    PubMed

    Iwata, T; Mikashima, H; Isobe, M; Takamatsu, R; Yokobe, T

    1989-11-01

    The pharmacokinetics of sodium 4-[alpha-hydroxy-5-(1-imidazolyl)-2-methylbenzyl]-3,5-dimethylbenzoat e (I-Na) in the beagle dog was investigated after p.o. and i.v. administration. After the administration of I-Na at 3 mg/kg (p.o.), 70.9% of the dose was absorbed, and the maximum plasma concentration of free acid (I) was observed at 0.33 h. After p.o. administration, the area under the plasma concentration-time curve of I increased almost linearly in proportion to the dose. The metabolite, 4-[alpha-hydroxy-2-hydroxymethyl-5-(1-imidazolyl)benzyl]-3,5-dimethyl benzoic acid (II) was also detected in the plasma, but the concentration of II was lower than that of I. After the administration at 3 mg/kg (p.o.), 27.7% and 3.8% of the dose were recovered as I and II, respectively, in the urine, and 32.2% and 30.1% recovered as I and II in the feces. Therefore, 93.8% of the dose was totally recovered within five days. The inhibitory effect of II on the aggregation of rabbit platelets was studied in vitro. This metabolite showed only one sixth activity of I-Na. Thus, the inhibitory effect on the platelet aggregation of II is considered to be almost negligible in the beagle dog administered with I-Na.

  18. Synthesis, biological evaluation, and molecular modeling studies of methylene imidazole substituted biaryls as inhibitors of human 17alpha-hydroxylase-17,20-lyase (CYP17)--part II: Core rigidification and influence of substituents at the methylene bridge.

    PubMed

    Hu, Qingzhong; Negri, Matthias; Jahn-Hoffmann, Kerstin; Zhuang, Yan; Olgen, Sureyya; Bartels, Marc; Müller-Vieira, Ursula; Lauterbach, Thomas; Hartmann, Rolf W

    2008-08-15

    Thirty-five novel substituted imidazolyl methylene biphenyls have been synthesized as CYP17 inhibitors for the potential treatment of prostate cancer. Their activities have been tested with recombinant human CYP17 expressed in Escherichia coli. Promising compounds were tested for selectivity against CYP11B1, CYP11B2, and hepatic CYP enzymes 3A4, 1A2, 2B6 and 2D6. The core rigidified compounds (30-35) were the most active ones, being much more potent than Ketoconazole and reaching the activity of Abiraterone. However, they were not very selective. Another rather potent and more selective inhibitor (compound 23, IC(50)=345 nM) was further examined in rats regarding plasma testosterone levels and pharmacokinetic properties. Compared to the reference Abiraterone, 23 was more active in vivo, showed a longer plasma half-life (10h) and a higher bioavailability. Using our CYP17 homology protein model, docking studies with selected compounds were performed to study possible interactions between inhibitors and amino acid residues of the active site.

  19. Discovery of mixed type thymidine phosphorylase inhibitors endowed with antiangiogenic properties: synthesis, pharmacological evaluation and molecular docking study of 2-thioxo-pyrazolo[1,5-a][1,3,5]triazin-4-ones. Part II.

    PubMed

    Bera, Hriday; Ojha, Probir kumar; Tan, Bee Jen; Sun, Lingyi; Dolzhenko, Anton V; Chui, Wai-Keung; Chiu, Gigi Ngar Chee

    2014-05-06

    In our drug discovery program, a series of 2-thioxo-pyrazolo[1,5-a][1,3,5]triazin-4-ones were designed, synthesized and evaluated for their TP inhibitory potential. All the synthesized analogues conferred a varying degree of TP inhibitory activity, comparable or better than positive control, 7-deazaxanthine (7-DX, 2) (IC50 value = 42.63 μM). A systematic approach to the lead optimization identified compounds 3c and 4a as the most promising TP inhibitors, exhibiting mixed mode of enzyme inhibition. Moreover, selected compounds demonstrated the ability to attenuate the expression of the angiogenic markers (viz. MMP-9 and VEGF) in MDA-MB-231 cells at sublethal concentrations. In addition, molecular docking studies revealed the plausible binding orientation of these inhibitors towards TP, which was in accordance with the experimental results. Taken as a whole, these compounds would constitute a new direction for the design of novel TP inhibitors with promising antiangiogenic properties.

  20. A new member of the plasma protease inhibitor gene family.

    PubMed Central

    Ragg, H

    1986-01-01

    A 2.1-kb cDNA clone representing a new member of the protease inhibitor family was isolated from a human liver cDNA library. The inhibitor, named human Leuserpin 2 (hLS2), comprises 480 amino acids and contains a leucine residue at its putative reactive center. HLS2 is about 25-28% homologous to three human members of the plasma protease inhibitor family: antithrombin III, alpha 1-antitrypsin and alpha 1-antichymotrypsin. A comparison with published partial amino acid sequences shows that hLS2 is closely related to the thrombin inhibitor heparin cofactor II. Images PMID:3003690

  1. 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.

  2. Topoisomerase II from Human Malaria Parasites

    PubMed Central

    Mudeppa, Devaraja G.; Kumar, Shiva; Kokkonda, Sreekanth; White, John; Rathod, Pradipsinh K.

    2015-01-01

    Historically, type II topoisomerases have yielded clinically useful drugs for the treatment of bacterial infections and cancer, but the corresponding enzymes from malaria parasites remain understudied. This is due to the general challenges of producing malaria proteins in functional forms in heterologous expression systems. Here, we express full-length Plasmodium falciparum topoisomerase II (PfTopoII) in a wheat germ cell-free transcription-translation system. Functional activity of soluble PfTopoII from the translation lysates was confirmed through both a plasmid relaxation and a DNA decatenation activity that was dependent on magnesium and ATP. To facilitate future drug discovery, a convenient and sensitive fluorescence assay was established to follow DNA decatenation, and a stable, truncated PfTopoII was engineered for high level enzyme production. PfTopoII was purified using a DNA affinity column. Existing TopoII inhibitors previously developed for other non-malaria indications inhibited PfTopoII, as well as malaria parasites in culture at submicromolar concentrations. Even before optimization, inhibitors of bacterial gyrase, GSK299423, ciprofloxacin, and etoposide exhibited 15-, 57-, and 3-fold selectivity for the malarial enzyme over human TopoII. Finally, it was possible to use the purified PfTopoII to dissect the different modes by which these varying classes of TopoII inhibitors could trap partially processed DNA. The present biochemical advancements will allow high throughput chemical screening of compound libraries and lead optimization to develop new lines of antimalarials. PMID:26055707

  3. Inhibitors of Pyruvate Carboxylase

    PubMed Central

    Zeczycki, Tonya N.; Maurice, Martin St.; Attwood, Paul V.

    2010-01-01

    This review aims to discuss the varied types of inhibitors of biotin-dependent carboxylases, with an emphasis on the inhibitors of pyruvate carboxylase. Some of these inhibitors are physiologically relevant, in that they provide ways of regulating the cellular activities of the enzymes e.g. aspartate and prohibitin inhibition of pyruvate carboxylase. Most of the inhibitors that will be discussed have been used to probe various aspects of the structure and function of these enzymes. They target particular parts of the structure e.g. avidin – biotin, FTP – ATP binding site, oxamate – pyruvate binding site, phosphonoacetate – binding site of the putative carboxyphosphate intermediate. PMID:22180764

  4. Acquired Factor V Inhibitor

    PubMed Central

    Hirai, Daisuke; Yamashita, Yugo; Masunaga, Nobutoyo; Katsura, Toshiaki; Akao, Masaharu; Okuno, Yoshiaki; Koyama, Hiroshi

    2016-01-01

    Inhibitors directed against factor V rarely occur, and the clinical symptoms vary. We herein report the case of a patient who presented with a decreased factor V activity that had decreased to <3 %. We administered vitamin K and 6 units of fresh frozen plasma, but she thereafter developed an intracerebral hemorrhage. It is unclear whether surgery >10 years earlier might have caused the development of a factor V inhibitor. The treatment of acquired factor V inhibitors is mainly the transfusion of platelet concentrates and corticosteroids. Both early detection and the early initiation of the treatment of factor V inhibitor are thus considered to be important. PMID:27746446

  5. Computational inhibitor design against malaria plasmepsins.

    PubMed

    Bjelic, S; Nervall, M; Gutiérrez-de-Terán, H; Ersmark, K; Hallberg, A; Aqvist, J

    2007-09-01

    Plasmepsins are aspartic proteases involved in the degradation of the host cell hemoglobin that is used as a food source by the malaria parasite. Plasmepsins are highly promising as drug targets, especially when combined with the inhibition of falcipains that are also involved in hemoglobin catabolism. In this review, we discuss the mechanism of plasmepsins I-IV in view of the interest in transition state mimetics as potential compounds for lead development. Inhibitor development against plasmepsin II as well as relevant crystal structures are summarized in order to give an overview of the field. Application of computational techniques, especially binding affinity prediction by the linear interaction energy method, in the development of malarial plasmepsin inhibitors has been highly successful and is discussed in detail. Homology modeling and molecular docking have been useful in the current inhibitor design project, and the combination of such methods with binding free energy calculations is analyzed.

  6. 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

  7. 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.

  8. Randomized Phase II Study of Dacomitinib (PF-00299804), an Irreversible Pan–Human Epidermal Growth Factor Receptor Inhibitor, Versus Erlotinib in Patients With Advanced Non–Small-Cell Lung Cancer

    PubMed Central

    Ramalingam, Suresh S.; Blackhall, Fiona; Krzakowski, Maciej; Barrios, Carlos H.; Park, Keunchil; Bover, Isabel; Seog Heo, Dae; Rosell, Rafael; Talbot, Denis C.; Frank, Richard; Letrent, Stephen P.; Ruiz-Garcia, Ana; Taylor, Ian; Liang, Jane Q.; Campbell, Alicyn K.; O'Connell, Joseph; Boyer, Michael

    2012-01-01

    Purpose This randomized, open-label trial compared dacomitinib (PF-00299804), an irreversible inhibitor of human epidermal growth factor receptors (EGFR)/HER1, HER2, and HER4, with erlotinib, a reversible EGFR inhibitor, in patients with advanced non–small-cell lung cancer (NSCLC). Patients and Methods Patients with NSCLC, Eastern Cooperative Oncology Group performance status 0 to 2, no prior HER-directed therapy, and one/two prior chemotherapy regimens received dacomitinib 45 mg or erlotinib 150 mg once daily. Results One hundred eighty-eight patients were randomly assigned. Treatment arms were balanced for most clinical and molecular characteristics. Median progression-free survival (PFS; primary end point) was 2.86 months for patients treated with dacomitinib and 1.91 months for patients treated with erlotinib (hazard ratio [HR] = 0.66; 95% CI, 0.47 to 0.91; two-sided P = .012); in patients with KRAS wild-type tumors, median PFS was 3.71 months for patients treated with dacomitinib and 1.91 months for patients treated with erlotinib (HR = 0.55; 95% CI, 0.35 to 0.85; two-sided P = .006); and in patients with KRAS wild-type/EGFR wild-type tumors, median PFS was 2.21 months for patients treated with dacomitinib and 1.84 months for patients treated with erlotinib (HR = 0.61; 95% CI, 0.37 to 0.99; two-sided P = .043). Median overall survival was 9.53 months for patients treated with dacomitinib and 7.44 months for patients treated with erlotinib (HR = 0.80; 95% CI, 0.56 to 1.13; two-sided P = .205). Adverse event-related discontinuations were uncommon in both arms. Common treatment-related adverse events were dermatologic and gastrointestinal, predominantly grade 1 to 2, and more frequent with dacomitinib. Conclusion Dacomitinib demonstrated significantly improved PFS versus erlotinib, with acceptable toxicity. PFS benefit was observed in most clinical and molecular subsets, notably KRAS wild-type/EGFR any status, KRAS wild-type/EGFR wild-type, and EGFR mutants

  9. High-throughput, semi-automated determination of a cyclooxygenase II inhibitor in human plasma and urine using solid-phase extraction in the 96-well format and high-performance liquid chromatography with post-column photochemical derivatization-fluorescence detection.

    PubMed

    Matthews, C Z; Woolf, E J; Lin, L; Fang, W; Hsieh, J; Ha, S; Simpson, R; Matuszewski, B K

    2001-02-25

    Compound I, 5-chloro-3-(4-methanesulfonylphenyl)-6'-methyl-[2,3']bipyridinyl, has been found to be a specific inhibitor of the enzyme cyclooxygenase II (COX II). The anti-inflammatory properties of this compound are currently being investigated. HPLC assays for the determination of this analyte in human plasma and human urine have been developed. Isolation of I and the internal standard (II) was achieved by solid-phase extraction (SPE) in the 96-well format. A C8 SPE plate was used for the extraction of the drug from human plasma (recovery >90%) while a mixed-mode (C8/Cation) SPE plate was used to isolate the analytes from human urine (recovery approximately 71%). The analyte and internal standard were chromatographed on a Keystone Scientific Prism-RP guard column (20 x 4.6 mm) connected to a Prism-RP analytical column (150 x 4.6 mm), using a mobile phase consisting of 45% acetonitrile in 10 mM acetate buffer (pH = 4); the analytes eluted at retention times of 5.2 and 6.9 min for I and II, respectively. Compounds I and II were found to form highly fluorescent products after exposure to UV light (254 nm). Thus, the analytes were detected by fluorescence (lambda(ex) = 260 nm, lambda(em) =375 nm) following post-column photochemical derivatization. Eight point calibration curves over the concentration range of 5-500 ng/ml for human plasma and human urine yielded a linear response (R2>0.99) when a 1/y weighted linear regression model was employed. Based on the replicate analyses (n = 5) of spiked standards, the within-day precision for both assays was better than 7% C.V. at all points on the calibration curve; within-day accuracy was within 5% of nominal at all standard concentrations. The between-run precision and accuracy of the assays, as calculated from the results of the analysis of quality control samples, was better than 8% C.V. and within 8% of nominal. I was found to be stable in human plasma and urine for at least 8 and 2 months, respectively. In addition, the

  10. CRYSTALLINE SOYBEAN TRYPSIN INHIBITOR

    PubMed Central

    Kunitz, M.

    1947-01-01

    A study has been made of the general properties of crystalline soybean trypsin inhibitor. The soy inhibitor is a stable protein of the globulin type of a molecular weight of about 24,000. Its isoelectric point is at pH 4.5. It inhibits the proteolytic action approximately of an equal weight of crystalline trypsin by combining with trypsin to form a stable compound. Chymotrypsin is only slightly inhibited by soy inhibitor. The reaction between chymotrypsin and the soy inhibitor consists in the formation of a reversibly dissociable compound. The inhibitor has no effect on pepsin. The inhibiting action of the soybean inhibitor is associated with the native state of the protein molecule. Denaturation of the soy protein by heat or acid or alkali brings about a proportional decrease in its inhibiting action on trypsin. Reversal of denaturation results in a proportional gain in the inhibiting activity. Crystalline soy protein when denatured is readily digestible by pepsin, and less readily by chymotrypsin and by trypsin. Methods are given for measuring trypsin and inhibitor activity and also protein concentration with the aid of spectrophotometric density measurements at 280 mµ. PMID:19873496

  11. Combination of ruthenium(II)-arene complex [Ru(η6-p-cymene)Cl2(pta)] (RAPTA-C) and the epidermal growth factor receptor inhibitor erlotinib results in efficient angiostatic and antitumor activity

    PubMed Central

    Berndsen, Robert H.; Weiss, Andrea; Abdul, U. Kulsoom; Wong, Tse J.; Meraldi, Patrick; Griffioen, Arjan W.; Dyson, Paul J.; Nowak-Sliwinska, Patrycja

    2017-01-01

    Ruthenium-based compounds show strong potential as anti-cancer drugs and are being investigated as alternatives to other well-established metal-based chemotherapeutics. The organometallic compound [Ru(η6-p-cymene)Cl2(pta)], where pta = 1,3,5-triaza-7-phosphaadamantane (RAPTA-C) exhibits broad acting anti-tumor efficacy with intrinsic angiostatic activity. In the search for an optimal anti-angiogenesis drug combination, we identified synergistic potential between RAPTA-C and the epidermal growth factor receptor (EGFR) inhibitor, erlotinib. This drug combination results in strong synergistic inhibition of cell viability in human endothelial (ECRF24 and HUVEC) and human ovarian carcinoma (A2780 and A2780cisR) cells. Additionally, erlotinib significantly enhances the cellular uptake of RAPTA-C relative to treatment with RAPTA-C alone in human ovarian carcinoma cells, but not endothelial cells. Drug combinations induce the formation of chromosome bridges that persist after mitotic exit and delay abscission in A2780 and A2780cisR, therefore suggesting initiation of cellular senescence. The therapeutic potential of these compounds and their combination is further validated in vivo on A2780 tumors grown on the chicken chorioallantoic membrane (CAM) model, and in a preclinical model in nude mice. Immunohistochemical analysis confirms effective anti-angiogenic and anti-proliferative activity in vivo, based on a significant reduction of microvascular density and a decrease in proliferating cells. PMID:28223694

  12. Photobilirubin II.

    PubMed Central

    Bonnett, R; Buckley, D G; Hamzetash, D; Hawkes, G E; Ioannou, S; Stoll, M S

    1984-01-01

    An improved preparation of photobilirubin II in ammoniacal methanol is described. Evidence is presented which distinguishes between the two structures proposed earlier for photobilirubin II in favour of the cycloheptadienyl structure. Nuclear-Overhauser-enhancement measurements with bilirubin IX alpha and photobilirubin II in dimethyl sulphoxide are complicated by the occurrence of negative and zero effects. The partition coefficient of photobilirubin II between chloroform and phosphate buffer (pH 7.4) is 0.67. PMID:6743241

  13. Footprinting of Inhibitor Interactions of In Silico Identified Inhibitors of Trypanothione Reductase of Leishmania Parasite

    PubMed Central

    Venkatesan, Santhosh K.; Dubey, Vikash Kumar

    2012-01-01

    Structure-based virtual screening of NCI Diversity set II compounds was performed to indentify novel inhibitor scaffolds of trypanothione reductase (TR) from Leishmania infantum. The top 50 ranked hits were clustered using the AuPoSOM tool. Majority of the top-ranked compounds were Tricyclic. Clustering of hits yielded four major clusters each comprising varying number of subclusters differing in their mode of binding and orientation in the active site. Moreover, for the first time, we report selected alkaloids and dibenzothiazepines as inhibitors of Leishmania infantum TR. The mode of binding observed among the clusters also potentiates the probable in vitro inhibition kinetics and aids in defining key interaction which might contribute to the inhibition of enzymatic reduction of T[S] 2. The method provides scope for automation and integration into the virtual screening process employing docking softwares, for clustering the small molecule inhibitors based upon protein-ligand interactions. PMID:22550471

  14. A class of sulfonamide carbonic anhydrase inhibitors with neuropathic pain modulating effects.

    PubMed

    Carta, Fabrizio; Di Cesare Mannelli, Lorenzo; Pinard, Melissa; Ghelardini, Carla; Scozzafava, Andrea; McKenna, Robert; Supuran, Claudiu T

    2015-04-15

    A series of benzene sulfonamide carbonic anhydrase (CA, EC 4.2.1.1) inhibitors which incorporate lipophilic 4-alkoxy- and 4-aryloxy moieties, together with several derivatives of ethoxzolamide and sulfanilamide are reported. These derivatives were investigated as inhibitors of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) of which multiple isoforms are known, and some appear to be involved in pain. These sulfonamides showed modest inhibition against the cytosolic isoform CA I, but were generally effective, low nanomolar CA II, VII, IX and XII inhibitors. X-ray crystallographic data for the adduct of several such sulfonamides with CA II allowed us to rationalize the good inhibition data. In a mice model of neuropathic pain induced by oxaliplatin, one of the strong CA II/VII inhibitors reported here induced a long lasting pain relieving effect, a fact never observed earlier. This is the first report of rationally designed sulfonamide CA inhibitors with pain effective modulating effects.

  15. 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.

  16. [Acquired coagulant factor inhibitors].

    PubMed

    Nogami, Keiji

    2015-02-01

    Acquired coagulation factor inhibitors are an autoimmune disease causing bleeding symptoms due to decreases in the corresponding factor (s) which result from the appearance of autoantibodies against coagulation factors (inhibitor). This disease is quite different from congenital coagulation factor deficiencies based on genetic abnormalities. In recent years, cases with this disease have been increasing, and most have anti-factor VIII autoantibodies. The breakdown of the immune control mechanism is speculated to cause this disease since it is common in the elderly, but the pathology and pathogenesis are presently unclear. We herein describe the pathology and pathogenesis of factor VIII and factor V inhibitors. Characterization of these inhibitors leads to further analysis of the coagulation process and the activation mechanisms of clotting factors. In the future, with the development of new clotting examination method (s), we anticipate that further novel findings will be obtained in this field through inhibitor analysis. In addition, detailed elucidation of the coagulation inhibitory mechanism possibly leading to hemostatic treatment strategies for acquired coagulation factor disorders will be developed.

  17. Aurora kinase inhibitors as anticancer molecules.

    PubMed

    Katayama, Hiroshi; Sen, Subrata

    2010-01-01

    Aurora kinase family of serine/threonine kinases are important regulators of mitosis that are frequently over expressed in human cancers and have been implicated in oncogenic transformation including development of chromosomal instability in cancer cells. In humans, among the three members of the kinase family, Aurora-A, -B and -C, only Aurora-A and -B are expressed at detectable levels in all somatic cells undergoing mitotic cell division and have been characterized in greater detail for their involvement in cellular pathways relevant to the development of cancer associated phenotypes. Aurora-A and -B are being investigated as potential targets for anticancer therapy. Development of inhibitors against Aurora kinases as anticancer molecules gained attention because of the facts that aberrant expression of these kinases leads to chromosomal instability and derangement of multiple tumor suppressor and oncoprotein regulated pathways. Preclinical studies and early phase I and II clinical trials of multiple Aurora kinase inhibitors as targeted anticancer drugs have provided encouraging results. This article discusses functional involvement of Aurora kinase-A and -B in the regulation of cancer relevant cellular phenotypes together with findings on some of the better characterized Aurora kinase inhibitors in modulating the functional interactions of Aurora kinases. Future possibilities about developing next generation Aurora kinase inhibitors and their clinical utility as anticancer therapeutic drugs are also discussed.

  18. Aurora Kinase inhibitors as Anticancer Molecules

    PubMed Central

    Katayama, Hiroshi; Sen, Subrata

    2015-01-01

    Aurora kinase family of serine/threonine kinases are important regulators of mitosis that are frequently over expressed in human cancers and have been implicated in oncogenic transformation including development of chromosomal instability in cancer cells. In humans, among the three members of the kinase family, Aurora-A, -B and -C, only Aurora-A and -B are expressed in detectable levels in somatic cells undergoing mitotic cell division and have been characterized in greater detail for their involvement in cellular pathways relevant to the development of cancer associated phenotypes. Aurora-A and -B are being investigated as potential targets for anticancer therapy. Development of inhibitors against Aurora kinases as anticancer molecules gained attention because of the facts that aberrant expression of these kinases lead to chromosomal instability and derangement of multiple tumor suppressor and oncoprotein regulated pathways. Pre-clinical studies and early phase I and II clinical trials of multiple Aurora kinase inhibitors as targeted anticancer drugs have provided encouraging results. This article discusses functional involvement of Aurora kinase-A and -B in the regulation of cancer relevant cellular phenotypes together with findings on some of the better characterized Aurora kinase inhibitors in modulating the functional interactions of Aurora kinases. Future possibilities about developing next generation Aurora kinase inhibitors and their clinical utility as anticancer therapeutic drugs are also discussed. PMID:20863917

  19. 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

  20. Thrombin inhibitor design.

    PubMed

    Sanderson, P E; Naylor-Olsen, A M

    1998-08-01

    Recently, iv formulated direct thrombin inhibitors have been shown to be safe and efficacious alternatives to heparin. These results have fueled the hopes for an orally active compound. Such a compound could be a significant advance over warfarin if it had predictable pharmacokinetics and a duration of action sufficient for once or twice a day dosing. In order to develop an orally active compound which meets these criteria, the deficiencies of the prototype inhibitor efegatran have had to be addressed. First, using a combination of structure based design and empirical structure optimization, more selective compounds have been identified by modifying the P1 group or by incorporating different peptidomimetic P2/P3 scaffolds. Secondly, this optimization has resulted in the development of potent and selective non-covalent inhibitors, thus bypassing the liabilities of the serine trap. Thirdly, oral bioavailability has been achieved while maintaining selectivity and efficacy through the incorporation of progressively less basic P1 groups. The duration of action of these compounds remains to be optimized. Other advances in thrombin inhibitor design have included the development of uncharged P1 groups and the discovery of two non-peptide templates.

  1. Inhibitors of acrosin and granulocyte proteinases from human genital tract secretions.

    PubMed

    Schiessler, H; Arnhold, M; Ohlsson, K; Fritz, H

    1976-09-01

    Human seminal plasma contains two acid-stable proteinase inhibitors, HUSI-II (Mr approximately 6500) and HUSI-I, (Mr approximately 11 000) with different inhibition specificities. The inhibitory activity of HUSI-II is strongly limited to trypsin and acrosin; both enzyme-inhibitor complexes are very stable (e.g. bovine trypsin-HUSI-II complex: Ki = 1 x 10(-10)M; human acrosin-HUSI-II complex: Ki = 2.7 x 10(-10)M). The inhibitor from human seminal plasma HUSI-II may therefore be seen as the natural antagonist of the sperm protease acrosin. In addition to pancreatic trypsin and alpha-chymotrypsin, HUSI-I forms strong complexes with neutral proteases of the lysosome-like granules from human granulocytes, for example, the elastase (Ki = 2.5 x 10(-9)M) and cathepsin G, the chymotrypsin like protease (Ki = 7 x 10(-8)M).

  2. Photosystem II

    ScienceCinema

    James Barber

    2016-07-12

    James Barber, Ernst Chain Professor of Biochemistry at Imperial College, London, gives a BSA Distinguished Lecture titled, "The Structure and Function of Photosystem II: The Water-Splitting Enzyme of Photosynthesis."

  3. Acyclic peptide inhibitors of amylases.

    PubMed

    Pohl, Nicola

    2005-12-01

    In this issue of Chemistry and Biology, a library screening approach reveals a linear octapeptide inhibitor of alpha-amylases reached by de novo design . The selected molecule shares characteristics with naturally occurring protein inhibitors -- a result that suggests general rules for the design of peptide-based amylase inhibitors may be achievable.

  4. [SGLT2 inhibitor].

    PubMed

    Kubota, Naoto; Kadowaki, Takashi

    2015-12-01

    SGLT2 is a glucose transporter which plays an important role for reabsorption of urinary glucose depending on the sodium concentration gradient. SGLT2 is mainly present in apical site of S1 segment of renal proximal tubule and accounts for approximately 90% of total urinary glucose reabsorption. SLC5a2, which codes SGLT2, is also known as the causative gene of familial renal glucosuria. SGLT2 inhibitors are attracting attention as newly developed oral anti-diabetic agents which improve glucose intolerance and also have an anti-obese effect by promoting urinary glucose excretion (UGE), which is a different pharmacological effect from other conventional anti-diabetic agents. In this review, we will discuss the effect of SGLT2 inhibitor on the regulation of glucose and lipid metabolism in type 2 diabetes.

  5. 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.

  6. Ii Chain Controls the Transport of Major Histocompatibility Complex Class II Molecules to and from Lysosomes

    PubMed Central

    Brachet, Valérie; Raposo, Graça; Amigorena, Sebastian; Mellman, Ira

    1997-01-01

    Major histocompatibility complex class II molecules are synthesized as a nonameric complex consisting of three αβ dimers associated with a trimer of invariant (Ii) chains. After exiting the TGN, a targeting signal in the Ii chain cytoplasmic domain directs the complex to endosomes where Ii chain is proteolytically processed and removed, allowing class II molecules to bind antigenic peptides before reaching the cell surface. Ii chain dissociation and peptide binding are thought to occur in one or more postendosomal sites related either to endosomes (designated CIIV) or to lysosomes (designated MIIC). We now find that in addition to initially targeting αβ dimers to endosomes, Ii chain regulates the subsequent transport of class II molecules. Under normal conditions, murine A20 B cells transport all of their newly synthesized class II I-Ab αβ dimers to the plasma membrane with little if any reaching lysosomal compartments. Inhibition of Ii processing by the cysteine/serine protease inhibitor leupeptin, however, blocked transport to the cell surface and caused a dramatic but selective accumulation of I-Ab class II molecules in lysosomes. In leupeptin, I-Ab dimers formed stable complexes with a 10-kD NH2-terminal Ii chain fragment (Ii-p10), normally a transient intermediate in Ii chain processing. Upon removal of leupeptin, Ii-p10 was degraded and released, I-Ab dimers bound antigenic peptides, and the peptide-loaded dimers were transported slowly from lysosomes to the plasma membrane. Our results suggest that alterations in the rate or efficiency of Ii chain processing can alter the postendosomal sorting of class II molecules, resulting in the increased accumulation of αβ dimers in lysosome-like MIIC. Thus, simple differences in Ii chain processing may account for the highly variable amounts of class II found in lysosomal compartments of different cell types or at different developmental stages. PMID:9105036

  7. Group II p21-activated kinases as therapeutic targets in gastrointestinal cancer

    PubMed Central

    Shao, Yang-Guang; Ning, Ke; Li, Feng

    2016-01-01

    P21-activated kinases (PAKs) are central players in various oncogenic signaling pathways. The six PAK family members are classified into group I (PAK1-3) and group II (PAK4-6). Focus is currently shifting from group I PAKs to group II PAKs. Group II PAKs play important roles in many fundamental cellular processes, some of which have particular significance in the development and progression of cancer. Because of their important functions, group II PAKs have become popular potential drug target candidates. However, few group II PAKs inhibitors have been reported, and most do not exhibit satisfactory kinase selectivity and “drug-like” properties. Isoform- and kinase-selective PAK inhibitors remain to be developed. This review describes the biological activities of group II PAKs, the importance of group II PAKs in the development and progression of gastrointestinal cancer, and small-molecule inhibitors of group II PAKs for the treatment of cancer. PMID:26811660

  8. Antagonism between curcumin and the topoisomerase II inhibitor etoposide

    PubMed Central

    Saleh, Ekram M.; El-awady, Raafat A; Eissa, Nadia A.; Abdel-Rahman, Wael M.

    2012-01-01

    The use of combinations of chemotherapy and natural products has recently emerged as a new method of cancer therapy, relying on the capacity of certain natural compounds to trigger cell death with low doses of chemotherapeutic agents and few side effects. The current study aims to evaluate the modulatory effects of curcumin (CUR), Nigella sativa (NS) and taurine on etoposide (ETP) cytotoxicity in a panel of cancer cell lines and to identify their underlying mechanisms. CUR alone showed potent antitumor activity, but surprisingly, its interaction with ETP was antagonistic in four out of five cancer cell lines. Neither taurine nor Nigella sativa affect the sensitivity of cancer cells to ETP. Examination of the DNA damage response machinery (DDR) showed that both ETP and CUR elicited DNA double-strand breaks (DSB) and evoked γ-H2AX foci formation at doses as low as 1 µg/ml. Cell cycle analysis revealed S phase arrest after ETP or CUR application, whereas co-treatment with ETP and CUR led to increased arrest of the cell cycle in S phase (MCF-7 cells) or the accumulation of cells in G2/M phases (HCT116, and HeLa cells). Furthermore, cotreatment with ETP and CUR resulted in modulation of the level of DNA damage induction and repair compared with either agent alone. Electron microscopic examination demonstrated that different modalities of cell death occurred with each treatment. CUR alone induced autophagy, apoptosis and necrosis, whereas ETP alone or in combination with CUR led to apoptosis and necrosis. Conclusions: Cotreatment with ETP and CUR resulted in an antagonistic interaction. This antagonism is related, in part, to the enhanced arrest of tumor cells in both S and G2/M phases, which prevents the cells from entering M-phase with damaged DNA and, consequently, prevents cell death from occurring. This arrest allows time for the cells to repair DNA damage so that cell cycle -arrested cells can eventually resume cell cycle progression and continue their physiological program. PMID:22895066

  9. [Angiotensin II inhibitors for the diagnosis and treatment of hypertension].

    PubMed

    Brunner, H R; Gavras, H

    1976-12-11

    Specific antagonists of the renin angiotensin system have been used to investigate the role of this hormonal system in blood pressure homeostasis and in different types of experimental and clinical hypertension. Using this approach it was possible to show that renin via angiotensin participates actively in blood pressure maintenace, particularly following sodium depletion. Such antagonists, if available for oral administration and taken together with a diuretic, would be useful therapeutically.

  10. Zn(II) transport and distribution in rat spermatids.

    PubMed

    Reyes, J G; Arrate, M P; Santander, M; Guzman, L; Benos, D J

    1993-10-01

    Zn(II) is an essential trace element. In spermatozoa, Zn(II) modulates metabolism and chromatin condensation. The mechanisms of uptake and distribution of this ion in sperm cells have not been explored. In rat spermatids, our results indicate that 1) 65Zn(II) binds with fast kinetics to a labile, presumably extracellular, compartment. This binding is temperature insensitive and not modified by metabolic inhibitors. 2) Entry of 65Zn(II) in the absence of externally added proteins occurs through a mediated transport system that allows exchange to reach steady state in approximately 15 min at 34 degrees C. 3) Upon entering the cells, 65Zn(II) binds tightly to cellular organelles. 4) Exchangeable Zn(II) bound to cytoplasmic proteins plus free intracellular Zn(II) appears to be < 20% of total exchangeable Zn(II). 5) The intracellular exchangeable Zn(II) compartment is decreased by metabolic inhibitors, showing a direct or indirect link between energy metabolism and cellular Zn(II) levels. 6) 65Zn(II) efflux from rat spermatids is a process with a rate constant of 0.16 +/- 0.13 min-1 at 34 degrees C. This exit rate of Zn(II) is likely to be affected by Zn(II) release from cytoplasmic binding sites or organelles.

  11. The potency and clinical efficacy of aromatase inhibitors across the breast cancer continuum

    PubMed Central

    Lønning, P. E.

    2011-01-01

    The strategy of using estrogen suppression to treat breast cancer led to the development of aromatase inhibitors, including the third-generation nonsteroidal compounds anastrozole and letrozole, and the steroidal compound exemestane. Aromatase inhibitors potently inhibit aromatase activity and also suppress estrogen levels in plasma and tissue. In clinical studies in postmenopausal women with breast cancer, third-generation aromatase inhibitors were shown superior to tamoxifen for the treatment of metastatic disease. Studies of adjuvant therapy with aromatase inhibitors include (i) head-to-head studies of 5 years of the aromatase inhibitor versus 5 years of tamoxifen monotherapy; (ii) sequential therapy of 2–3 years of tamoxifen followed by an aromatase inhibitor (or the opposite sequence) versus 5 years of tamoxifen monotherapy; (iii) extended therapy with an aromatase inhibitor after 5 years of tamoxifen; and (iv) sequential therapy with an aromatase inhibitor versus aromatase inhibitor monotherapy. Recent results from the Arimidex, Tamoxifen, Alone or in Combination and Breast International Group 1–98 trials advocate using an aromatase inhibitor upfront. This article examines the clinical data with aromatase inhibitors, following a brief summary of their pharmacology. PMID:20616198

  12. 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.

  13. 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

  14. Screening of selective histone deacetylase inhibitors by proteochemometric modeling

    PubMed Central

    2012-01-01

    Background Histone deacetylase (HDAC) is a novel target for the treatment of cancer and it can be classified into three classes, i.e., classes I, II, and IV. The inhibitors selectively targeting individual HDAC have been proved to be the better candidate antitumor drugs. To screen selective HDAC inhibitors, several proteochemometric (PCM) models based on different combinations of three kinds of protein descriptors, two kinds of ligand descriptors and multiplication cross-terms were constructed in our study. Results The results show that structure similarity descriptors are better than sequence similarity descriptors and geometry descriptors in the leftacterization of HDACs. Furthermore, the predictive ability was not improved by introducing the cross-terms in our models. Finally, a best PCM model based on protein structure similarity descriptors and 32-dimensional general descriptors was derived (R2 = 0.9897, Qtest2 = 0.7542), which shows a powerful ability to screen selective HDAC inhibitors. Conclusions Our best model not only predict the activities of inhibitors for each HDAC isoform, but also screen and distinguish class-selective inhibitors and even more isoform-selective inhibitors, thus it provides a potential way to discover or design novel candidate antitumor drugs with reduced side effect. PMID:22913517

  15. Quaternary ammonium sulfanilamide: a membrane-impermeant carbonic anhydrase inhibitor.

    PubMed

    Henry, R P

    1987-05-01

    A novel carbonic anhydrase (CA) inhibitor, quaternary ammonium sulfanilamide (QAS), was tested for potency as a CA inhibitor and for its ability to be excluded from permeating biological membranes. Inhibitor titration plots of QAS vs. pure bovine CA II and CA from the gills of the blue crab, Callinectes sapidus, yielded Ki values of approximately 15 microM; thus QAS is a relatively weak but effective CA inhibitor. Permeability of the QAS was directly tested by two independent methods. The inhibitor was excluded from human erythrocytes incubated in 5 mM QAS for 24 h as determined using an 18O-labeled mass spectrometer CA assay for intact cells. Also QAS injected into the hemolymph of C. sapidus (1 or 10 mM) did not cross the basal membrane of the gill. The compound was cleared from the hemolymph by 96 h after injection, and at no time during that period could the QAS be detected in homogenates of gill tissue. Total branchial CA activity was only slightly reduced following the QAS injection. These data indicate that QAS is a CA inhibitor to which biological membranes are impermeable and that can be used in vivo or in vitro in the study of membrane-associated CA.

  16. FAQs II

    ERIC Educational Resources Information Center

    Kezar, Adrianna; Frank, Vikki; Lester, Jaime; Yang, Hannah

    2008-01-01

    In their paper entitled "Why should postsecondary institutions consider partnering to offer (Individual Development Accounts (IDAs)?" the authors reviewed frequently asked questions they encountered from higher education professionals about IDAs, but as their research continued so did the questions. FAQ II has more in-depth questions and…

  17. SAGE II

    Atmospheric Science Data Center

    2016-02-16

    ... of stratospheric aerosols, ozone, nitrogen dioxide, water vapor and cloud occurrence by mapping vertical profiles and calculating ... (i.e. MLS and SAGE III versus HALOE) Fixed various bugs Details are in the  SAGE II V7.00 Release Notes .   ...

  18. Prospects of β-Secretase Inhibitors for the Treatment of Alzheimer's Disease.

    PubMed

    Ghosh, Arun K; Tang, Jordan

    2015-09-01

    β-Secretase continues to be an attractive drug discovery target for the therapeutic intervention of Alzheimer's disease (AD). This enzyme plays a critical role in the production of neurotoxic β-amyloid (Aβ) peptides in the brain. Over the years, extensive research efforts have led to the development of many promising classes of inhibitors against this protease. Many small-molecule, peptidomimetic, and nonpeptide β-secretase inhibitors have now overcome the key challenging development hurdles such as selectivity and brain penetration. A number of inhibitors have also shown further promise in reducing brain Aβ and rescuing cognitive decline in animal models. Recently, several β-secretase inhibitors have entered into preclinical and phase I studies, and at least one of these inhibitors has advanced to phase II/III human trials. The outlook on β-secretase inhibitor drugs for the treatment of AD patients is discussed herein.

  19. Gamma II

    NASA Astrophysics Data System (ADS)

    Barker, Thurburn; Castelaz, M.; Cline, J.; Owen, L.; Boehme, J.; Rottler, L.; Whitworth, C.; Clavier, D.

    2011-05-01

    GAMMA II is the Guide Star Automatic Measuring MAchine relocated from STScI to the Astronomical Photographic Data Archive (APDA) at the Pisgah Astronomical Research Institute (PARI). GAMMA II is a multi-channel laser-scanning microdensitometer that was used to measure POSS and SERC plates to create the Guide Star Catalog and the Digital Sky Survey. The microdensitometer is designed with submicron accuracy in x and y measurements using a HP 5507 laser interferometer, 15 micron sampling, and the capability to measure plates as large as 0.5-m across. GAMMA II is a vital instrument for the success of digitizing the direct, objective prism, and spectra photographic plate collections in APDA for research. We plan several targeted projects. One is a collaboration with Drs. P.D. Hemenway and R. L. Duncombe who plan to scan 1000 plates of 34 minor planets to identify systematic errors in the Fundamental System of celestial coordinates. Another is a collaboration with Dr. R. Hudec (Astronomical Institute, Academy of Sciences of the Czech Republic) who is working within the Gaia Variability Unit CU7 to digitize objective prism spectra on the Henize plates and Burrell-Schmidt plates located in APDA. These low dispersion spectral plates provide optical counterparts of celestial high-energy sources and cataclysmic variables enabling the simulation of Gaia BP/RP outputs. The astronomical community is invited to explore the more than 140,000 plates from 20 observatories now archived in APDA, and use GAMMA II. The process of relocating GAMMA to APDA, re-commissioning, and starting up the production scan programs will be described. Also, we will present planned research and future upgrades to GAMMA II.

  20. [Tyrosine kinase inhibitors].

    PubMed

    Robert, Jacques

    2011-11-01

    Membrane receptors with tyrosine kinase activity and cytoplasmic tyrosine kinases have emerged as important potential targets in oncology. Starting from basic structures such as anilino-quinazoline, numerous compounds have been synthesised, with the help of tyrosine kinase crystallography, which has allowed to optimise protein-ligand interactions. The catalytic domains of all kinases present similar three-dimensional structures, which explains that it may be difficult to identify molecules having a high specificity for a given tyrosine kinase. Some tyrosine kinase inhibitors are relatively specific for epidermal growth factor receptor (EGFR) such as géfitinib and erlotinib; other are mainly active against platelet-derived growth factor receptor (PDGFR) and the receptor KIT, such as imatinib or nilotinib, and other against vascular endothelial growth factor (VEGF) receptors involved in angiogenesis, such as sunitinib and sorafenib. The oral formulation of tyrosine kinase inhibitors is well accepted by the patients but may generate sometimes compliance problems requiring pharmacokinetic monitoring. This chemical family is in full expansion and several dozens of compounds have entered clinical trials.

  1. Ets-1 upregulation mediates angiotensin II-related cardiac fibrosis.

    PubMed

    Hao, Guanghua; Han, Zhenhua; Meng, Zhe; Wei, Jin; Gao, Dengfeng; Zhang, Hong; Wang, Nanping

    2015-01-01

    Ets-1, the prototypical member of the family of Ets transcription factors, has been shown to participate in tissue fibrotic remodeling. However, its role in cardiac fibrosis has not been established. The aim of this study was to investigate the role of Ets-1 in profibrotic actions of angiotensin II (Ang II) in cardiac fibroblasts (CFs) and in the in vivo heart. In growth-arrested CFs, Ang II induced Ets-1 expression in a time- and concentration-dependent manner. Pretreatment with Ang II type 1 receptor blocker losartan, protein kinase C inhibitor bisindolylmaleimide I, extracellular signal-regulated kinase (ERK) inhibitor PD98059, or c-Jun NH(2)-terminal kinase (JNK) inhibitor SP600125 partly inhibited this induction accompanied with impaired cell proliferation and production of plasminogen activator inhibitor-1 (PAI-1) and connective tissue growth factor (CTGF) protein, the two downstream targets of Ets-1. Knockdown of Ets-1 by siRNA significantly inhibited the inductive effects of Ang II on cell proliferation and expression of CTGF and PAI-1. Moreover, the levels of Ets-1, PAI-1 and CTGF protein were simultaneously upregulated in left ventricle of Ang II-infused rats in parallel with an increase in the activation of ERK and JNK. Our data suggest that Ets-1 may mediate Ang II-induced cardiac fibrotic effects.

  2. 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.

  3. Positioning of aminopeptidase inhibitors in next generation cancer therapy.

    PubMed

    Hitzerd, Sarina M; Verbrugge, Sue Ellen; Ossenkoppele, Gert; Jansen, Gerrit; Peters, Godefridus J

    2014-04-01

    Aminopeptidases represent a class of (zinc) metalloenzymes that catalyze the cleavage of amino acids nearby the N-terminus of polypeptides, resulting in hydrolysis of peptide bonds. Aminopeptidases operate downstream of the ubiquitin-proteasome pathway and are implicated in the final step of intracellular protein degradation either by trimming proteasome-generated peptides for antigen presentation or full hydrolysis into free amino acids for recycling in renewed protein synthesis. This review focuses on the function and subcellular location of five key aminopeptidases (aminopeptidase N, leucine aminopeptidase, puromycin-sensitive aminopeptidase, leukotriene A4 hydrolase and endoplasmic reticulum aminopeptidase 1/2) and their association with different diseases, in particular cancer and their current position as target for therapeutic intervention by aminopeptidase inhibitors. Historically, bestatin was the first prototypical aminopeptidase inhibitor that entered the clinic 35 years ago and is still used for the treatment of lung cancer. More recently, new generation aminopeptidase inhibitors became available, including the aminopeptidase inhibitor prodrug tosedostat, which is currently tested in phase II clinical trials for acute myeloid leukemia. Beyond bestatin and tosedostat, medicinal chemistry has emerged with additional series of potential aminopeptidases inhibitors which are still in an early phase of (pre)clinical investigations. The expanded knowledge of the unique mechanism of action of aminopeptidases has revived interest in aminopeptidase inhibitors for drug combination regimens in anti-cancer treatment. In this context, this review will discuss relevant features and mechanisms of action of aminopeptidases and will also elaborate on factors contributing to aminopeptidase inhibitor efficacy and/or loss of efficacy due to drug resistance-related phenomena. Together, a growing body of data point to aminopeptidase inhibitors as attractive tools for

  4. Differential regulation of Bdnf expression in cortical neurons by class-selective histone deacetylase inhibitors.

    PubMed

    Koppel, Indrek; Timmusk, Tõnis

    2013-12-01

    Histone deactylase (HDAC) inhibitors show promise as therapeutics for neurodegenerative and psychiatric diseases. Increased expression of brain-derived neurotrophic factor (BDNF) has been associated with memory-enhancing and neuroprotective properties of these drugs, but the mechanism of BDNF induction is not well understood. Here, we compared the effects of a class I/IIb selective HDAC inhibitor SAHA, a class I selective inhibitor MS-275, a class II selective inhibitor MC1568 and a HDAC6 selective inhibitor tubacin on Bdnf mRNA expression in rat primary neurons. We show that inhibition of class II HDACs resulted in rapid upregulation of Bdnf mRNA levels, whereas class I HDAC inhibition produced a markedly delayed Bdnf induction. In contrast to relatively slow upregulation of Bdnf transcripts, histone acetylation at BDNF promoters I and IV was rapidly induced by SAHA. Bdnf induction by SAHA and MS-275 at 24 h was sensitive to protein synthesis inhibition, suggesting that delayed Bdnf induction by HDAC inhibitors is secondary to changed expression of its regulators. HDAC4 and HDAC5 repressed Bdnf promoter IV activity, supporting the role of class II HDACs in regulation of Bdnf expression. In addition, we show a critical role for the cAMP/Ca2+ response element (CRE) in induction of Bdnf promoter IV by MS-275, MC1568, SAHA and sodium valproate. In contrast, MEF2-binding CaRE1 element was not necessary for promoter IV induction by HDAC inhibition. Finally, we show that similarly to Bdnf, the studied HDAC inhibitors differentially induced expression of neuronal activity-regulated genes c-fos and Arc. Together, our findings implicate class II HDACs in transcriptional regulation of Bdnf and indicate that class II selective HDAC inhibitors may have potential as therapeutics for nervous system disorders.

  5. Purification and Characteristics of an Endogenous α-Amylase Inhibitor from Barley Kernels 1

    PubMed Central

    Weselake, Randall J.; MacGregor, Alexander W.; Hill, Robert D.; Duckworth, Harry W.

    1983-01-01

    An inhibitor of malted barley (Hordeum vulgare cv Conquest) α-amylase II was purified 125-fold from a crude extract of barley kernels by (NH4)2SO4 fractionation, ion exchange chromatography on DEAE-Sephacel, and gel filtration on Bio-Gel P 60. The inhibitor was a protein with an approximate molecular weight of 20,000 daltons and an isoelectric point of 7.3. The protein was homogeneous, as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Amino acid analysis indicated the presence of about 9 half-cystine residues per mole. The neutral isoelectric point of the inhibitor suggested that some of the apparently acidic residues (glutamic and aspartic) existed in the amide form. The first twenty N-terminal amino acids were sequenced. Some homology appeared to exist between the α-amylase II inhibitor and trypsin inhibitor from barley. Complex formation between α-amylase II and the inhibitor was detected by the appearance of a new molecular weight species after gel filtration on Bio-Gel P 100. Enzyme and inhibitor had to be preincubated for 5 min, prior to assaying for enzyme activity before maximum inhibition was attained. Inhibition increased at higher pH values. At pH 5.5, an approximately 1100 molar excess of inhibitor over α-amylase II produced 40% inhibition, whereas, at pH 8.0, a 1:1 molar ratio of inhibitor to enzyme produced the same degree of inhibition. PMID:16663319

  6. New therapeutic strategies in HCV: second-generation protease inhibitors.

    PubMed

    Clark, Virginia C; Peter, Joy A; Nelson, David R

    2013-02-01

    Telaprevir and boceprevir are the first direct-acting antiviral agents approved for use in HCV treatment and represent a significant advance in HCV therapy. However, these first-generation drugs also have significant limitations related to thrice-daily dosing, clinically challenging side-effect profiles, low barriers to resistance and a lack of pan-genotype activity. A second wave of protease inhibitors are in phase II and III trials and promise to provide a drug regimen with a better dosing schedule and improved tolerance. These second-wave protease inhibitors will probably be approved in combination with PEG-IFN and Ribavirin (RBV), as well as future all-oral regimens. The true second-generation protease inhibitors are in earlier stages of development and efficacy data are anxiously awaited as they may provide pan-genotypic antiviral activity and a high genetic barrier to resistance.

  7. Small Molecule Inhibitors Targeting Activator Protein 1 (AP-1)

    PubMed Central

    2015-01-01

    Activator protein 1 (AP-1) is a pivotal transcription factor that regulates a wide range of cellular processes including proliferation, apoptosis, differentiation, survival, cell migration, and transformation. Accumulating evidence supports that AP-1 plays an important role in several severe disorders including cancer, fibrosis, and organ injury, as well as inflammatory disorders such as asthma, psoriasis, and rheumatoid arthritis. AP-1 has emerged as an actively pursued drug discovery target over the past decade. Excitingly, a selective AP-1 inhibitor T-5224 (51) has been investigated in phase II human clinical trials. Nevertheless, no effective AP-1 inhibitors have yet been approved for clinical use. Despite significant advances achieved in understanding AP-1 biology and function, as well as the identification of small molecules modulating AP-1 associated signaling pathways, medicinal chemistry efforts remain an urgent need to yield selective and efficacious AP-1 inhibitors as a viable therapeutic strategy for human diseases. PMID:24831826

  8. Development of tau aggregation inhibitors for Alzheimer's disease.

    PubMed

    Bulic, Bruno; Pickhardt, Marcus; Schmidt, Boris; Mandelkow, Eva-Maria; Waldmann, Herbert; Mandelkow, Eckhard

    2009-01-01

    A variety of human diseases are suspected to be directly linked to protein misfolding. Highly organized protein aggregates, called amyloid fibrils, and aggregation intermediates are observed; these are considered to be mediators of cellular toxicity and thus attract a great deal of attention from investigators. Neurodegenerative pathologies such as Alzheimer's disease account for a major part of these protein misfolding diseases. The last decade has witnessed a renaissance of interest in inhibitors of tau aggregation as potential disease-modifying drugs for Alzheimer's disease and other "tauopathies". The recent report of a phase II clinical trial with the tau aggregation inhibitor MTC could hold promise for the validation of the concept. This Review summarizes the available data concerning small-molecule inhibitors of tau aggregation from a medicinal chemistry point of view.

  9. A Novel Inhibitor of the Obesity-Related Protein FTO.

    PubMed

    Qiao, Yan; Zhou, Bin; Zhang, Meizi; Liu, Weijia; Han, Zhifu; Song, Chuanjun; Yu, Wenquan; Yang, Qinghua; Wang, Ruiyong; Wang, Shaomin; Shi, Shuai; Zhao, Renbin; Chai, Jijie; Chang, Junbiao

    2016-03-15

    Fe(II) and α-ketoglutarate-dependent fat mass and obesity associated protein (FTO)-dependent demethylation of m⁶A is important for regulation of mRNA splicing and adipogenesis. Developing FTO-specific inhibitors can help probe the biology of FTO and unravel novel therapeutic targets for treatment of obesity or obesity-associated diseases. In the present paper, we have identified that 4-chloro-6-(6'-chloro-7'-hydroxy-2',4',4'-trimethyl-chroman-2'-yl)benzene-1,3-diol (CHTB) is an inhibitor of FTO. The crystal structure of CHTB complexed with human FTO reveals that the novel small molecule binds to FTO in a specific manner. The identification of the novel small molecule offers opportunities for further development of more selective and potent FTO inhibitors.

  10. Small molecule inhibitors targeting activator protein 1 (AP-1).

    PubMed

    Ye, Na; Ding, Ye; Wild, Christopher; Shen, Qiang; Zhou, Jia

    2014-08-28

    Activator protein 1 (AP-1) is a pivotal transcription factor that regulates a wide range of cellular processes including proliferation, apoptosis, differentiation, survival, cell migration, and transformation. Accumulating evidence supports that AP-1 plays an important role in several severe disorders including cancer, fibrosis, and organ injury, as well as inflammatory disorders such as asthma, psoriasis, and rheumatoid arthritis. AP-1 has emerged as an actively pursued drug discovery target over the past decade. Excitingly, a selective AP-1 inhibitor T-5224 (51) has been investigated in phase II human clinical trials. Nevertheless, no effective AP-1 inhibitors have yet been approved for clinical use. Despite significant advances achieved in understanding AP-1 biology and function, as well as the identification of small molecules modulating AP-1 associated signaling pathways, medicinal chemistry efforts remain an urgent need to yield selective and efficacious AP-1 inhibitors as a viable therapeutic strategy for human diseases.

  11. PORT II

    NASA Technical Reports Server (NTRS)

    Muniz, Beau

    2009-01-01

    One unique project that the Prototype lab worked on was PORT I (Post-landing Orion Recovery Test). PORT is designed to test and develop the system and components needed to recover the Orion capsule once it splashes down in the ocean. PORT II is designated as a follow up to PORT I that will utilize a mock up pressure vessel that is spatially compar able to the final Orion capsule.

  12. Sequencing of aromatase inhibitors

    PubMed Central

    Bertelli, G

    2005-01-01

    Since the development of the third-generation aromatase inhibitors (AIs), anastrozole, letrozole and exemestane, these agents have been the subject of intensive research to determine their optimal use in advanced breast cancer. Not only have they replaced progestins in second-line therapy and challenged the role of tamoxifen in first-line, but there is also evidence for a lack of cross-resistance between the steroidal and nonsteroidal AIs, meaning that they may be used in sequence to obtain prolonged clinical benefit. Many questions remain, however, as to the best sequence of the two types of AIs and of the other available agents, including tamoxifen and fulvestrant, in different patient groups. PMID:16100523

  13. Sirtuin activators and inhibitors

    PubMed Central

    Villalba, José M.; Alcaín, Francisco J.

    2012-01-01

    Sirtuins 1-7 (SIRT1-7) belong to the third class of deacetylase enzymes, which are dependent on NAD+ for activity. Sirtuins activity is linked to gene repression, metabolic control, apoptosis and cell survival, DNA repair, development, inflammation, neuroprotection and healthy aging. Because sirtuins modulation could have beneficial effects on human diseases there is a growing interest in the discovery of small molecules modifying their activity. We review here those compounds known to activate or inhibit sirtuins, discussing the data that support the use of sirtuin-based therapies. Almost all sirtuin activators have been described only for SIRT1. Resveratrol is a natural compound which activates SIRT1, and may help in the treatment or prevention of obesity, and in preventing tumorigenesis and the aging-related decline in heart function and neuronal loss. Due to its poor bioavailability, reformulated versions of resveratrol with improved bioavailability have been developed (resVida, Longevinex®, SRT501). Molecules that are structurally unrelated to resveratrol (SRT1720, SRT2104, SRT2379, among others) have been also developed to stimulate sirtuin activities more potently than resveratrol. Sirtuin inhibitors with a wide range of core structures have been identified for SIRT1, SIRT2, SIRT3 and SIRT5 (splitomicin, sirtinol, AGK2, cambinol, suramin, tenovin, salermide, among others). SIRT1 inhibition has been proposed in the treatment of cancer, immunodeficiency virus infections, Fragile X mental retardation syndrome and for preventing or treating parasitic diseases, whereas SIRT2 inhibitors might be useful for the treatment of cancer and neurodegenerative diseases. PMID:22730114

  14. 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 ...

  15. [ACE inhibitors from the viewpoint of the clinical pharmacologist].

    PubMed

    Hitzenberger, G

    1996-01-01

    For treatment of hypertension drugs are desirable which exert a 24 hours lasting blood pressure control. Among the ACE-inhibitors some drugs exist which have this action. The elimination pathway plays a minor role in this respect. Not only the inhibition of Angiotensin II generation but also the decreased inhibition of bradykinin-degeneration plays a crucial role with regard to several endothelial functions controlling the so called remodeling of the cardiovascular system.

  16. Authentic HIV-1 integrase inhibitors

    PubMed Central

    Liao, Chenzhong; Marchand, Christophe; Burke, Terrence R; Pommier, Yves; Nicklaus, Marc C

    2010-01-01

    HIV-1 integrase (IN) is indispensable for HIV-1 replication and has become a validated target for developing anti-AIDS agents. In two decades of development of IN inhibition-based anti-HIV therapeutics, a significant number of compounds were identified as IN inhibitors, but only some of them showed antiviral activity. This article reviews a number of patented HIV-1 IN inhibitors, especially those that possess high selectivity for the strand transfer reaction. These compounds generally have a polar coplanar moiety, which is assumed to chelate two magnesium ions in the binding site. Resistance to those compounds, when given to patients, can develop as a result of IN mutations. We refer to those compounds as authentic IN inhibitors. Continued drug development has so far delivered one authentic IN inhibitor to the market (raltegravir in 2007). Current and future attention will be focused on the development of novel authentic IN inhibitors with the goal of overcoming viral resistance. PMID:21426159

  17. Cocrystal Structures of Primed Side-Extending α-Ketoamide Inhibitors Reveal Novel Calpain-Inhibitor Aromatic Interactions

    SciTech Connect

    Qian,J.; Cuerrier, D.; Davies, P.; Li, Z.; Powers, J.; Campbell, R.

    2008-01-01

    Calpains are intracellular cysteine proteases that catalyze the cleavage of target proteins in response to Ca2+ signaling. When Ca2+ homeostasis is disrupted, calpain overactivation causes unregulated proteolysis, which can contribute to diseases such as postischemic injury and cataract formation. Potent calpain inhibitors exist, but of these many cross-react with other cysteine proteases and will need modification to specifically target calpain. Here, we present crystal structures of rat calpain 1 protease core ({mu}I-II) bound to two a-ketoamide-based calpain inhibitors containing adenyl and piperazyl primed-side extensions. An unexpected aromatic-stacking interaction is observed between the primed-side adenine moiety and the Trp298 side chain. This interaction increased the potency of the inhibitor toward {mu}I-II and heterodimeric m-calpain. Moreover, stacking orients the adenine such that it can be used as a scaffold for designing novel primed-side address regions, which could be incorporated into future inhibitors to enhance their calpain specificity.

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

    SciTech Connect

    Xu, Jie; Zeng, Li-Fan; Shen, Weihua; Turchi, John J.; Zhang, Zhong-Yin

    2013-10-04

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

  19. Oxadiazoles and thiadiazoles: novel α-glucosidase inhibitors.

    PubMed

    Kashtoh, Hamdy; Hussain, Shafqat; Khan, Ajmal; Saad, Syed Muhammad; Khan, Jalaluddin A J; Khan, Khalid Mohammed; Perveen, Shahnaz; Choudhary, M Iqbal

    2014-10-01

    Oxadiazoles and thiadiazoles 1-37 were synthesized and evaluated for the first time for their α-glucosidase inhibitory activities. As a result, fifteen of them 1, 4, 5, 7, 8, 13, 17, 23, 25, 30, 32, 33, 35, 36 and 37 were identified as potent inhibitors of the enzyme. Kinetic studies of the most active compounds (oxadiazoles 1, 23 and 25, and thiadiazoles 35 and 37) were carried out to determine their mode of inhibition and dissociation constants Ki. The most potent compound of the oxadiazole series (compound 23) was found to be a non-competitive inhibitor (Ki=4.36±0.017 μM), while most potent thiadiazole 35 was identified as a competitive inhibitor (Ki=6.0±0.059 μM). The selectivity and toxicity of these compounds were also studied by evaluating their potential against other enzymes, such as carbonic anhydrase-II and phosphodiesterase-I. Cytotoxicity was evaluated against rat fibroblast 3T3 cell line. Interestingly, these compounds were found to be inactive against other enzymes, exhibiting their selectivity towards α-glucosidase. Inhibition of α-glucosidase is an effective strategy for controlling post-prandial hyperglycemia in diabetic patients. α-Glucosidase inhibitors can also be used as anti-obesity and anti-viral drugs. Our study identifies two novel series of potent α-glucosidase inhibitors for further investigation.

  20. 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.

  1. Design and synthesis of lactam-thiophene carboxylic acids as potent hepatitis C virus polymerase inhibitors.

    PubMed

    Barnes-Seeman, David; Boiselle, Carri; Capacci-Daniel, Christina; Chopra, Rajiv; Hoffmaster, Keith; Jones, Christopher T; Kato, Mitsunori; Lin, Kai; Ma, Sue; Pan, Guoyu; Shu, Lei; Wang, Jianling; Whiteman, Leah; Xu, Mei; Zheng, Rui; Fu, Jiping

    2014-08-15

    Herein we report the successful incorporation of a lactam as an amide replacement in the design of hepatitis C virus NS5B Site II thiophene carboxylic acid inhibitors. Optimizing potency in a replicon assay and minimizing potential risk for CYP3A4 induction led to the discovery of inhibitor 22a. This lead compound has a favorable pharmacokinetic profile in rats and dogs.

  2. Identification of two novel RET kinase inhibitors through MCR-based drug discovery: design, synthesis and evaluation.

    PubMed

    Frett, Brendan; Moccia, Marialuisa; Carlomagno, Francesca; Santoro, Massimo; Li, Hong-yu

    2014-10-30

    From an MCR fragment library, two novel chemical series have been developed as inhibitors of RET, which is a kinase involved in the pathology of medullary thyroid cancer (MTC). Structure activity relationship studies (SAR) identified two sub-micromolar tractable leads, 6g and 13g. 6g was confirmed to be a Type-II RET inhibitor. 13g and 6g inhibited RET in cells transformed by RET/C634. A RET DFG-out homology model was established and utilized to predict Type-II inhibitor binding modes.

  3. Identification of two novel RET kinase inhibitors through MCR-based drug discovery: Design, synthesis and evaluation

    PubMed Central

    Frett, Brendan; Moccia, Marialuisa; Carlomagno, Francesca; Santoro, Massimo; Li, Hong-yu

    2015-01-01

    From an MCR fragment library, two novel chemical series have been developed as inhibitors of RET, which is a kinase involved in the pathology of medullary thyroid cancer (MTC). Structure activity relationship studies (SAR) identified two sub-micromolar tractable leads, 6g and 13g. 6g was confirmed to be a Type-II RET inhibitor. 13g and 6g inhibited RET in cells transformed by RET/C634. A RET DFG-out homology model was established and utilized to predict Type-II inhibitor binding modes. PMID:25232968

  4. High Proteolytic Resistance of Spider-Derived Inhibitor Cystine Knots

    PubMed Central

    Kikuchi, Kyoko; Sugiura, Mika; Kimura, Tadashi

    2015-01-01

    Proteolytic stability in gastrointestinal tract and blood plasma is the major obstacle for oral peptide drug development. Inhibitor cystine knots (ICKs) are linear cystine knot peptides which have multifunctional properties and could become promising drug scaffolds. ProTx-I, ProTx-II, GTx1-15, and GsMTx-4 were spider-derived ICKs and incubated with pepsin, trypsin, chymotrypsin, and elastase in physiological conditions to find that all tested peptides were resistant to pepsin, and ProTx-II, GsMTx-4, and GTx1-15 showed resistance to all tested proteases. Also, no ProTx-II degradation was observed in rat blood plasma for 24 hours in vitro and ProTx-II concentration in circulation decreased to half in 40 min, indicating absolute stability in plasma and fast clearance from the system. So far, linear peptides are generally thought to be unsuitable in vivo, but all tested ICKs were not degraded by pepsin and stomach could be selected for the alternative site of drug absorption for fast onset of the drug action. Since spider ICKs are selective inhibitors of various ion channels which are related to the pathology of many diseases, engineered ICKs will make a novel class of peptide medicines which can treat variety of bothering symptoms. PMID:26843868

  5. New drug development in head and neck squamous cell carcinoma: The PI3-K inhibitors.

    PubMed

    De Felice, Francesca; Guerrero Urbano, Teresa

    2017-04-01

    Over the last few years a number of new different compounds have been developed. They include phosphatidylinositol 3-kinase (PI3-K) inhibitors. Deregulation within the PI3-K pathway is common in head neck squamous cell carcinoma (HNSCC) and it represents a growing area of research. PI3-K inhibitors, including BKM120, PX-866 and BYL719, are being tested in several phase I and phase II studies in patients with locally advanced, recurrent or metastatic disease. This review provides an update of published clinical trials and highlights the challenges of PI3-K inhibitors in HNSCC.

  6. [ACE inhibitors and the kidney].

    PubMed

    Hörl, W H

    1996-01-01

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

  7. 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

  8. Racial differences in blood pressure response to angiotensin-converting enzyme inhibitors in children: a meta-analysis.

    PubMed

    Li, J S; Baker-Smith, C M; Smith, P B; Hasselblad, V; Murphy, M D; Califf, R M; Benjamin, D K

    2008-09-01

    Angiotensin-converting enzyme (ACE) inhibitors are frequently used to treat hypertension in children.(1) ACE inhibitors alter the balance between the vasoconstrictive, salt-retentive, and cardiac hypertrophic properties of angiotensin II and the vasodilatory and natriuretic properties of bradykinin; they also alter the metabolism of other vasoactive substances.(2) Through these mechanisms, ACE inhibitors decrease systemic vascular resistance and promote natriuresis without increasing heart rate. This study evaluated the results of six trials of ACE inhibitors in children, using meta-analytic techniques to estimate the effect of race on blood pressure response.

  9. Identification and characterization of alpha-I-proteinase inhibitor from common carp sarcoplasmic proteins.

    PubMed

    Siriangkanakun, Siriphon; Li-Chan, Eunice C Y; Yongsawadigul, Jirawat

    2016-02-01

    Purification of proteinase inhibitor from common carp (Cyprinus carpio) sarcoplasmic proteins resulted in 2.8% yield with purification fold of 111. Two inhibitors, namely inhibitor I and II, exhibited molecular mass of 47 and 52 kDa, respectively, based on non-reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Both inhibitors I and II were identified to be alpha-1-proteinase inhibitor (α1-PI) based on LC-MS/MS. They were glycoproteins and molecular mass after peptide-N-glycosidase F treatment was 38 and 45 kDa, respectively. The N-glycosylation sites of both inhibitors were determined to be at N214 and N226. The inhibitors specifically inhibited trypsin. The common carp α1-PI showed high thermal stability with denaturation temperatures of 65.43 and 73.31 °C, which were slightly less than those of ovomucoid. High stability toward NaCl was also evident up to 3M. The common carp α1-PI effectively reduced autolytic degradation of bigeye snapper surimi at the concentration as low as 0.025%.

  10. Mannostatin A, a new glycoprotein-processing inhibitor.

    PubMed

    Tropea, J E; Kaushal, G P; Pastuszak, I; Mitchell, M; Aoyagi, T; Molyneux, R J; Elbein, A D

    1990-10-30

    Mannostatin A is a metabolite produced by the microorganism Streptoverticillium verticillus and reported to be a potent competitive inhibitor of rat epididymal alpha-mannosidase. When tested against a number of other arylglycosidases, mannostatin A was inactive toward alpha- and beta-glucosidase and galactosidase as well as beta-mannosidase, but it was a potent inhibitor of jack bean, mung bean, and rat liver lysosomal alpha-mannosidases, with estimated IC50's of 70 nM, 450 nM, and 160 nM, respectively. The type of inhibition was competitive in nature. This compound also proved to be an effective competitive inhibitor of the glycoprotein-processing enzyme mannosidase II (IC50 of about 10-15 nM with p-nitrophenyl alpha-D-mannopyranoside as substrate, and about 90 nM with [3H]mannose-labeled GlcNAc-Man5GlcNAc as substrate). However, it was virtually inactive toward mannosidase I. The N-acetylated derivative of mannostatin A had no inhibitory activity. In cell culture studies, mannostatin A also proved to be a potent inhibitor of glycoprotein processing. Thus, in influenza virus infected Madin Darby canine kidney (MDCK) cells, mannostatin A blocked the normal formation of complex types of oligosaccharides on the viral glycoproteins and caused the accumulation of hybrid types of oligosaccharides. This observation is in keeping with other data which indicate that the site of action of mannostatin A is mannosidase II. Thus, mannostatin A represents the first nonalkaloidal processing inhibitor and adds to the growing list of chemical structures that can have important biological activity.

  11. Mannostatin A, a new glycoprotein-processing inhibitor

    SciTech Connect

    Tropea, J.E.; Kaushal, G.P.; Pastuszak, I.; Mitchell, M.; Elbein, A.D. ); Aoyagi, Takaaki ); Molyneux, R.J. )

    1990-10-01

    Mannostatin A is a metabolite produced by the microorganism Streptoverticillium verticillus and reported to be a potent competitive inhibitor of rat epididymal {alpha}-mannosidase. When tested against a number of other arylglycosidases, mannostatin A was inactive toward {alpha}- and {beta}-glucosidase and galactosidase as well as {beta}-mannosidase, but it was a potent inhibitor of jack bean, mung bean, and rat liver lysosomal {alpha}-mannosidases, with estimated IC{sub 50}'s of 70 nM, 450 nM, and 160 nM, respectively. The type of inhibition was competitive in nature. This compound also proved to be an effective competitive inhibitor of the glycoprotein-processing enzyme mannosidase II (IC{sub 50} of about 10-15 nM with p-nitrophenyl {alpha}-D-mannopyranoside as substrate, and about 90 nM with ({sup 3}H)mannose-labeled GlcNAc-Man{sub 5}GlcNAc as substrate). However, it was virtually inactive toward mannosidase I. The N-acetylated derivative of mannostatin A had no inhibitory activity. In cell culture studies, mannostatin A also proved to be a potent inhibitor of glycoprotein processing. Thus, in influenza virus infected Madin Darby canine kidney (MDCK) cells, mannostatin A blocked the normal formation of complex types of oligosaccharides on the viral glycoproteins and caused the accumulation of hybrid types of oligosaccharides. This observation is in keeping with other data which indicate that the site of action of mannostatin A is mannosidase II. Thus, mannostatin A represents the first nonalkaloidal processing inhibitor and adds to the growing list of chemical structures that can have important biological activity.

  12. Inhibitors of pig kidney trehalase.

    PubMed

    Kyosseva, S V; Kyossev, Z N; Elbein, A D

    1995-02-01

    Trehazolin, a new trehalase inhibitor isolated from the culture broth of Micromonospora, was reported to be a highly specific inhibitor for porcine and silk worm trehalases with IC50 values of 5.5 x 10(-9) and 3.7 x 10(-9) M, respectively (O. Ando, H. Satake, K. Itoi, A. Sato, M. Nakajima, S. Takashi, H. Haruyama, Y. Ohkuma, T. Kinoshita, and R. Enokita (1991) J. Antibiot. 44, 1165-1168). We also found that trehazolin is a very powerful and quite specific inhibitor against purified pig kidney trehalase, giving an IC50 value of 1.9 x 10(-8) M. Lineweaver-Burk plots showed that this compound was a competitive inhibitor of the trehalase. However, even at concentrations of 200 micrograms/ml, trehazolin did not inhibit the rat intestinal maltase or sucrase, yeast alpha-glucosidase or almond beta-glucosidase. Validoxylamine A and validamycin A, two other trehalase inhibitors, showed potent competitive inhibition against purified pig kidney trehalase, with IC50 values of 2.4 x 10(-9) and 2.5 x 10(-4) M, respectively. On the other hand, validoxylamine A was almost inactive against rat intestinal sucrase and maltase, with some inhibition being observed at millimolar concentration. A number of other glucosidase inhibitors, such as MDL 25637, castanospermine, and deoxynojirimycin were also tested against the purified trehalase and showed reasonable inhibitory activity.

  13. Purification and partial characterization of human neutrophil elastase inhibitors from the marine snail Cenchritis muricatus (Mollusca).

    PubMed

    González, Yamile; Tanaka, Aparecida S; Hirata, Izaura Y; del Rivero, Maday Alonso; Oliva, Maria L V; Araujo, Mariana S; Chávez, Maria A

    2007-04-01

    Human neutrophil elastase inhibition was detected in a crude extract of the marine snail Cenchritis muricatus (Gastropoda, Mollusca). This inhibitory activity remained after heating this extract at 60 degrees C for 30 min. From this extract, three human neutrophil elastase inhibitors (designated CmPI-I, CmPI-II and CmPI-III) were purified by affinity and reversed-phase chromatographies. Homogeneity of CmPI-I and CmPI-II was confirmed, while CmPI-III showed a single peak in reversed-phase chromatography, but heterogeneity in SDS-PAGE with preliminary molecular masses in the range of 18.4 to 22.0 kDa. In contrast, MALDI-TOF mass spectrometry of CmPI-I and CmPI-II showed that these inhibitors are molecules of low molecular mass, 5576 and 5469 Da, respectively. N-terminal amino acid sequences of CmPI-I (6 amino acids) and CmPI-II (20 amino acids) were determined. Homology to Kazal-type protease inhibitors was preliminarily detected for CmPI-II. Both inhibitors, CmPI-I and CmPI-II are able to inhibit human neutrophil elastase strongly, with equilibrium dissociation constant (Ki) values of 54.2 and 1.6 nM, respectively. In addition, trypsin and pancreatic elastase were also inhibited, but not plasma kallikrein or thrombin. CmPI-I and CmPI-II are the first human neutrophil elastase inhibitors described in a mollusk.

  14. The cytochrome P450 inhibitor SKF-525A disrupts autophagy in primary rat hepatocytes.

    PubMed

    Luo, Yong; Yang, Xi; Shi, Qiang

    2016-08-05

    The cytochrome P450 (CYP) inhibitor SKF-525A is commonly used to study drug metabolism and toxicity, particularly hepatotoxicity. By using Western blot and immunofluorescence staining, we unexpectedly found that SKF-525A at 2-20 μM caused remarkable accumulation of microtubule-associated protein light chain 3 II (LC3-II) in primary rat hepatocytes at 1, 4 and 24 h, indicating that autophagy was disrupted. SKF-525A showed no effects on chloroquine induced LC3-II accumulation, suggesting that autophagic flux was blocked, which is further supported by the increased level of the p62 protein after SKF-525A treatment. SKF-525A did not affect proteasome activities or gene expression of LC3-II or p62. Immunofluorescence of green fluorescent protein fused lysosomal-associated membrane protein 1 (LAMP1, a specific protein marker for lysosomes) and LC3-II showed that co-localization of these two proteins was partially abolished by SKF-525A, indicating that autophagosome-lysosome fusion was blocked. The other five CYP inhibitors, metyrapone, 1-aminobenzotriazole, alpha-naphthoflavone, ticlopidine, and ketoconazole, showed no effects in parallel experiments. These findings provide novel insights into the mechanisms by which various CYP inhibitors differentially affect a same drug's toxicity in hepatocytes. The data also indicate that SKF-525A is not an ideal chemical inhibitor for probing the relation between CYP mediated metabolism and toxicity in primary hepatocytes.

  15. Angiotensin-converting enzyme inhibitor (enalapril maleate) accelerates recovery of mouse skin from UVB-induced wrinkles

    SciTech Connect

    Matsuura-Hachiya, Yuko; Arai, Koji Y.; Ozeki, Rieko; Kikuta, Ayako; Nishiyama, Toshio

    2013-12-06

    Highlights: •Angiotensin converting enzyme (ACE) increases in UVB-irradiated skin. •Administration of an ACE inhibitor improved UVB-induced skin wrinkle. •ACE inhibitor improved UVB-induced epidermal hypertrophy. •ACE inhibitor improved transepidermal water loss in the UVB-irradiated skin. -- Abstract: Angiotensin-converting enzyme (ACE) activity and angiotensin II signaling regulate cell proliferation, differentiation, and tissue remodeling, as well as blood pressure, while in skin, angiotensin II signaling is involved in wound healing, inflammation, and pathological scar formation. Therefore, we hypothesized that angiotensin II is also involved in photoaging of skin. In this study, we examined the effect of enalapril maleate, an ACE inhibitor, on recovery of wrinkled skin of hairless mice exposed to long-term UVB irradiation. Immunohistochemical observation revealed that expression of ACE, angiotensin II, and angiotensin II type 1 (AT1) and type 2 (AT2) receptors in the skin was increased after UVB irradiation (3 times/week at increasing intensities for 8 weeks). Administration of enalapril maleate (5 times/week for 6 weeks, starting 1 week after 10-week irradiation) accelerated recovery from UVB-induced wrinkles, epidermal hyperplasia and epidermal barrier dysfunction, as compared with the vehicle control. Our results indicate that ACE and angiotensin II activity are involved in skin photoaging, and suggest that ACE inhibitor such as enalapril maleate may have potential for improvement of photoaged skin.

  16. Angiotensin II activates endothelial constitutive nitric oxide synthase via AT1 receptors.

    PubMed

    Saito, S; Hirata, Y; Emori, T; Imai, T; Marumo, F

    1996-09-01

    To determine whether angiotensin (ANG) II, a vasoconstrictor hormone, activates constitutive nitric oxide synthase (cNOS) in endothelial cells (ECs), we investigated the cellular mechanism by which ANG II induces nitric oxide (NO) formation in cultured bovine ECs. ANG II rapidly (within 1 min) and dose-dependently (10(-9)-10(-6) M) increased nitrate/nitrite (NOx) production. This effect of ANG II was abolished by a NOS inhibitor, NG-monomethyl-L-arginine. An ANG II type 1 (AT1) receptor antagonist (DuP 753), but not an ANG II type 2 (AT2) receptor antagonist (PD 123177), dose-dependently inhibited ANG II-induced NOx production. A Ca(2+)-channel blocker (barnidipine) failed to affect ANG II-induced NOx production, whereas an intracellular Ca2+ chelator (BAPTA) and a calmodulin inhibitor (W-7) abolished NOx production induced by ANG II. A protein kinase C (PKC) inhibitor (H-7) and down-regulation of endogenous PKC after pretreatment with phorbol ester decreased NOx production stimulated by ANG II. ANG II transiently stimulated inositol 1,4,5-trisphosphate (IP3) formation, and increased cytosolic free Ca2+ concentrations; these effects were blocked by DuP 753. Our data demonstrate that ANG II stimulates NO release by activation of Ca2+/calmodulin-dependent cNOS via AT1 receptors in bovine ECs.

  17. Engineering trypsin for inhibitor resistance.

    PubMed

    Batt, Anna R; St Germain, Commodore P; Gokey, Trevor; Guliaev, Anton B; Baird, Teaster

    2015-09-01

    The development of effective protease therapeutics requires that the proteases be more resistant to naturally occurring inhibitors while maintaining catalytic activity. A key step in developing inhibitor resistance is the identification of key residues in protease-inhibitor interaction. Given that majority of the protease therapeutics currently in use are trypsin-fold, trypsin itself serves as an ideal model for studying protease-inhibitor interaction. To test the importance of several trypsin-inhibitor interactions on the prime-side binding interface, we created four trypsin single variants Y39A, Y39F, K60A, and K60V and report biochemical sensitivity against bovine pancreatic trypsin inhibitor (BPTI) and M84R ecotin. All variants retained catalytic activity against small, commercially available peptide substrates [kcat /KM  = (1.2 ± 0.3) × 10(7) M(-1 ) s(-1) . Compared with wild-type, the K60A and K60V variants showed increased sensitivity to BPTI but less sensitivity to ecotin. The Y39A variant was less sensitive to BPTI and ecotin while the Y39F variant was more sensitive to both. The relative binding free energies between BPTI complexes with WT, Y39F, and Y39A were calculated based on 3.5 µs combined explicit solvent molecular dynamics simulations. The BPTI:Y39F complex resulted in the lowest binding energy, while BPTI:Y39A resulted in the highest. Simulations of Y39F revealed increased conformational rearrangement of F39, which allowed formation of a new hydrogen bond between BPTI R17 and H40 of the variant. All together, these data suggest that positions 39 and 60 are key for inhibitor binding to trypsin, and likely more trypsin-fold proteases.

  18. Inhibition of chymotrypsin by heparin cofactor II.

    PubMed Central

    Church, F C; Noyes, C M; Griffith, M J

    1985-01-01

    Human heparin cofactor II is a plasma protein that is known to inhibit thrombin. The rate of thrombin inhibition by heparin cofactor II is accelerated (greater than or equal to 1000-fold) in the presence of the glycosaminoglycans, heparin and dermatan sulfate. We have found that chymotrypsin A alpha is also inhibited by heparin cofactor II with a second-order rate constant value of 1.8 X 10(6) M-1 X min-1 at pH 8.0 and 25 degrees C. However, there was no measurable effect of heparin or dermatan sulfate on the rate of chymotrypsin inhibition. Arginine-modified heparin cofactor II showed a comparable percentage loss of both antichymotrypsin and antithrombin activities. Heparin cofactor II and chymotrypsin formed a stable complex with a Mr value near 90,000 when analyzed by NaDodSO4/polyacrylamide gel electrophoresis; this suggests a 1:1 reaction stoichiometry. The chymotrypsin cleavage site in heparin cofactor II was the same as that for thrombin, and primary structure analysis of the inhibitor showed a P'1-P'8 sequence of Ser-Thr-Gln-Val-Arg-Phe-Thr-Val ... . The results indicate that, in contrast to alpha 1-antichymotrypsin, which does not inhibit trypsin-like enzymes, including thrombin, heparin cofactor II can effectively inhibit both thrombin and chymotrypsin. PMID:3863104

  19. ROCK inhibitor prevents the dedifferentiation of human articular chondrocytes

    SciTech Connect

    Matsumoto, Emi; Furumatsu, Takayuki; Kanazawa, Tomoko; Tamura, Masanori; Ozaki, Toshifumi

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer ROCK inhibitor stimulates chondrogenic gene expression of articular chondrocytes. Black-Right-Pointing-Pointer ROCK inhibitor prevents the dedifferentiation of monolayer-cultured chondrocytes. Black-Right-Pointing-Pointer ROCK inhibitor enhances the redifferentiation of cultured chondrocytes. Black-Right-Pointing-Pointer ROCK inhibitor is useful for preparation of un-dedifferentiated chondrocytes. Black-Right-Pointing-Pointer ROCK inhibitor may be a useful reagent for chondrocyte-based regeneration therapy. -- Abstract: Chondrocytes lose their chondrocytic phenotypes in vitro. The Rho family GTPase ROCK, involved in organizing the actin cytoskeleton, modulates the differentiation status of chondrocytic cells. However, the optimum method to prepare a large number of un-dedifferentiated chondrocytes is still unclear. In this study, we investigated the effect of ROCK inhibitor (ROCKi) on the chondrogenic property of monolayer-cultured articular chondrocytes. Human articular chondrocytes were subcultured in the presence or absence of ROCKi (Y-27632). The expression of chondrocytic marker genes such as SOX9 and COL2A1 was assessed by quantitative real-time PCR analysis. Cellular morphology and viability were evaluated. Chondrogenic redifferentiation potential was examined by a pellet culture procedure. The expression level of SOX9 and COL2A1 was higher in ROCKi-treated chondrocytes than in untreated cells. Chondrocyte morphology varied from a spreading form to a round shape in a ROCKi-dependent manner. In addition, ROCKi treatment stimulated the proliferation of chondrocytes. The deposition of safranin O-stained proteoglycans and type II collagen was highly detected in chondrogenic pellets derived from ROCKi-pretreated chondrocytes. Our results suggest that ROCKi prevents the dedifferentiation of monolayer-cultured chondrocytes, and may be a useful reagent to maintain chondrocytic phenotypes in vitro for chondrocyte

  20. Effect of glycoprotein-processing inhibitors on fucosylation of glycoproteins

    SciTech Connect

    Schwarz, P.M.; Elbein, A.D.

    1985-11-25

    Influenza viral hemagglutinin contains L-fucose linked alpha 1,6 to some of the innermost GlcNAc residues of the complex oligosaccharides. To determine what structural features of the oligosaccharide were required for fucosylation influenza virus-infected MDCK cells were incubated in the presence of various inhibitors of glycoprotein processing to stop trimming at different points. After several hours of incubation with the inhibitors, (5,6-TH)fucose and (1- UC)mannose were added to label the glycoproteins, and cells were incubated in inhibitor and isotope for about 40 h to produce mature virus. Glycopeptides were prepared from the viral and the cellular glycoproteins, and these glycopeptides were isolated by gel filtration on Bio-Gel P-4. The glycopeptides were then digested with endo-beta-N-acetylglucosaminidase H and rechromatographed on the Bio-Gel column. In the presence of castanospermine or 2,5-dihydroxymethyl-3,4-dihydroxypyrrolidine, both inhibitors of glucosidase I, most of the radioactive mannose was found in Glc3Man7-9GlcNAc structures, and these did not contain radioactive fucose. In the presence of deoxymannojirimycin, an inhibitor of mannosidase I, most of the ( UC)mannose was in a Man9GlcNAc structure which was also not fucosylated. However, in the presence of swainsonine, an inhibitor of mannosidase II, the ( UC)mannose was mostly in hybrid types of oligosaccharides, and these structures also contained radioactive fucose. Treatment of the hybrid structures with endoglucosaminidase H released the (TH)fucose as a small peptide (Fuc-GlcNAc-peptide), whereas the ( UC)mannose remained with the oligosaccharide. The data support the conclusion that the addition of fucose linked alpha 1,6 to the asparagine-linked GlcNAc is dependent upon the presence of a beta 1,2-GlcNAc residue on the alpha 1,3-mannose branch of the core structure.

  1. [New anticoagulants - direct thrombin inhibitors].

    PubMed

    Brand, B; Graf, L

    2012-11-01

    Direct thrombin-inhibitors inactivate not only free but also fibrin-bound thrombin. The group of parenteral direct thrombin-inhibitors includes the recombinant hirudins lepirudin and desirudin, the synthetic hirudin bivalirudin, and the small molecule argatroban. All these compounds do not interact with PF4/heparin-antibodies. Therefore, argatroban as well as bivalirudin are currently used to treat heparin-induced thrombocytopenia (HIT). The oral direct thrombin-inhibitor dabigatran etexilate is already licensed in many countries for the treatment of non-valvular atrial fibrillation. Dabigatran etexilate reveals a stable and predictable effect that allows a medication without dose adjustment or monitoring. The substance shows only few interactions with other drugs but strong inhibitors of p-glycoprotein can increase plasma levels of dabigatran substantially. After oral intake, the prodrug dabigatran etexilate is cleaved by esterase-mediated hydrolyses to the active compound dabigatran. Elimination of dabigatran is predominantly renal. Safety and efficacy of dabigatran etexilate were tested in an extensive clinical study program. Non-inferiority compared to current standard treatments was shown for prophylaxis of venous thromboembolic events after total knee and hip replacement, for stroke prevention in atrial fibrillation, and for treatment of acute venous thromboembolism. In daily practice, Dabigatran etexilate competes against the new direct factor Xa-inhibitors. In the absence of direct comparative clinical trials, it is not yet clear if one class of substances has distinct advantages over the other.

  2. Juggling jobs: roles and mechanisms of multifunctional protease inhibitors in plants.

    PubMed

    Grosse-Holz, Friederike M; van der Hoorn, Renier A L

    2016-05-01

    Multifunctional protease inhibitors juggle jobs by targeting different enzymes and thereby often controlling more than one biological process. Here, we discuss the biological functions, mechanisms and evolution of three types of multifunctional protease inhibitors in plants. The first type is double-headed inhibitors, which feature two inhibitory sites targeting proteases with different specificities (e.g. Bowman-Birk inhibitors) or even different hydrolases (e.g. α-amylase/protease inhibitors preventing both early germination and seed predation). The second type consists of multidomain inhibitors which evolved by intragenic duplication and are released by processing (e.g. multicystatins and potato inhibitor II, implicated in tuber dormancy and defence, respectively). The third type consists of promiscuous inhibitory folds which resemble mouse traps that can inhibit different proteases cleaving the bait they offer (e.g. serpins, regulating cell death, and α-macroglobulins). Understanding how multifunctional inhibitors juggle biological jobs increases our knowledge of the connections between the networks they regulate. These examples show that multifunctionality evolved independently from a remarkable diversity of molecular mechanisms that can be exploited for crop improvement and provide concepts for protein design.

  3. Selectivity of IMAC columns in trypsin inhibitor purification.

    PubMed

    Yeomans-Reina, H; Ruiz-Manriquez, A; Wong, B R; Mansir, A T

    2001-01-01

    The properties of an adsorbent and the parameters in an adsorption process affect the resolution of chromatographic purifications. This is reflected in the elution profile, which shows the relative affinity of different proteins for a specific adsorbent. In the work presented here, elution profiles for trypsin inhibitor were used to study the effects of the concentration of trypsin inhibitor, ionic strength of the protein solution, slope of the elution gradient, and the regeneration treatment of the chromatography column on the selectivity of the adsorbent Cellufine Chelate-Cu(II)(ida). Cytochrome c was used as a reference protein. Variations in the concentrations of trypsin inhibitor and in the ionic strength of the buffered solution did not have any effects on the elution profile. On the other hand, changes in the slope of the pH gradient used for elution caused shifting of the elution peaks toward lower values of the elution volume, resulting in the best strategy to modify the elution profile of the system. Finally, using a constant slope pH gradient of elution, the variation of the selectivity of the adsorbent for trypsin inhibitor when subjected to cleaning treatments with 0.5 N NaOH was studied. Appropriate cleaning practices used in industry were followed. The adsorbent showed only a slight tendency for resolution loss in the order of 2 x 10(-4) days(-1). The results presented here show a good stability of the adsorbent when compared to other biospecific adsorbents commonly used.

  4. Exploring the inhibitor binding pocket of respiratory complex I.

    PubMed

    Fendel, Uta; Tocilescu, Maja A; Kerscher, Stefan; Brandt, Ulrich

    2008-01-01

    Numerous hydrophobic and amphipathic compounds including several detergents are known to inhibit the ubiquinone reductase reaction of respiratory chain complex I (proton pumping NADH:ubiquinone oxidoreductase). Guided by the X-ray structure of the peripheral arm of complex I from Thermus thermophilus we have generated a large collection of site-directed mutants in the yeast Yarrowia lipolytica targeting the proposed ubiquinone and inhibitor binding pocket of this huge multiprotein complex at the interface of the 49-kDa and PSST subunits. We could identify a number of residues where mutations changed I(50) values for representatives from all three groups of hydrophobic inhibitors. Many mutations around the domain of the 49-kDa subunit that is homologous to the [NiFe] centre binding region of hydrogenase conferred resistance to DQA (class I/type A) and rotenone (class II/type B) indicating a wider overlap of the binding sites for these two types of inhibitors. In contrast, a region near iron-sulfur cluster N2, where the binding of the n-alkyl-polyoxyethylene-ether detergent C(12)E(8) (type C) was exclusively affected, appeared comparably well separated. Taken together, our data provide structure-based support for the presence of distinct but overlapping binding sites for hydrophobic inhibitors possibly extending into the ubiquinone reduction site of mitochondrial complex I.

  5. 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%.

  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, 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.

  8. An environmentally friendly scale inhibitor

    SciTech Connect

    Dobbs, J.B.; Brown, J.M.

    1999-11-01

    This paper describes a method of inhibiting the formation of scales such as barium and strontium sulfate in low pH aqueous systems, and calcium carbonate in systems containing high concentrations of dissolved iron. The solution, chemically, involves treating the aqueous system with an inhibitor designed to replace organic-phosphonates. Typical low pH aqueous systems where the inhibitor is particularly useful are oilfield produced-water, resin bed water softeners that form scale during low pH, acid regeneration operations. Downhole applications are recommended where high concentrations of dissolved iron are present in the produced water. This new approach to inhibition replaces typical organic phosphonates and polymers with a non-toxic, biodegradable scale inhibitor that performs in harsh environments.

  9. 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.

  10. 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.

  11. 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

  12. [Kinase inhibitors against hematological malignancies].

    PubMed

    Tojo, Arinobu

    2014-06-01

    Dysregulation of protein phosphorylation, especially on tyrosine residues, plays a crucial role in development and progression of hematological malignancies. Since remarkable success in imatinib therapy of CML and Ph+ALL, extensive efforts have made to explore candidate molecular targets and next breakthrough drugs. Now that next generation ABL kinase inhibitors are available for CML, the therapeutic algorithm has been revolutionized. As for AML and lymphoid malignancies, many kinase inhibitors targeting FLT3, BTK and aurora-A are on early and late clinical trials, and a number of promising drugs including ibrutinib are picked up for further evaluation.

  13. Identification and characterization of small-molecule inhibitors of hepsin

    PubMed Central

    Chevillet, John R.; Park, Gemma J.; Bedalov, Antonio; Simon, Julian A.; Vasioukhin, Valeri I.

    2009-01-01

    Hepsin is a type-II transmembrane serine protease overexpressed in the majority of human prostate cancers. We recently demonstrated that hepsin promotes prostate cancer progression and metastasis and thus represents a potential therapeutic target. Here we report the identification of novel small-molecule inhibitors of hepsin catalytic activity. We utilized purified human hepsin for high-throughput screening of established drug and chemical diversity libraries and identified sixteen inhibitory compounds with IC50 values against hepsin ranging from 0.23–2.31μM and relative selectivity of up to 86-fold or greater. Two compounds are orally administered drugs established for human use. Four compounds attenuated hepsin-dependent pericellular serine protease activity in a dose dependent manner with limited or no cytotoxicity to a range of cell types. These compounds may be used as leads to develop even more potent and specific inhibitors of hepsin to prevent prostate cancer progression and metastasis. PMID:18852137

  14. Lysine Deacetylase Inhibitors in Parasites: Past, Present, and Future Perspectives.

    PubMed

    Hailu, Gebremedhin S; Robaa, Dina; Forgione, Mariantonietta; Sippl, Wolfgang; Rotili, Dante; Mai, Antonello

    2017-03-15

    Current therapies for human parasite infections rely on a few drugs, most of which have severe side effects, and their helpfulness is being seriously compromised by the drug resistance problem. Globally, this is pushing discovery research of antiparasitic drugs toward new agents endowed with new mechanisms of action. By using a "drug repurposing" strategy, histone deacetylase inhibitors (HDACi), which are presently clinically approved for cancer use, are now under investigation for various parasite infections. Because parasitic Zn(2+)- and NAD(+)-dependent HDACs play crucial roles in the modulation of parasite gene expression and many of them are pro-survival for several parasites under various conditions, they are now emerging as novel potential antiparasitic targets. This Perspective summarizes the state of knowledge of HDACi (both class I/II HDACi and sirtuin inhibitors) targeted to the main human parasitic diseases (schistosomiasis, malaria, trypanosomiasis, leishmaniasis, and toxoplasmosis) and provides visions into the main issues that challenge their development as antiparasitic agents.

  15. Cystatins, serpins and other families of protease inhibitors in plants.

    PubMed

    Volpicella, Mariateresa; Leoni, Claudia; Costanza, Alessandra; De Leo, Francesca; Gallerani, Raffaele; Ceci, Luigi R

    2011-08-01

    Plant protease inhibitors (PIs) are generally small proteins present in high concentrations in storage tissues (tubers and seeds), and to a lower level in leaves. Even if most of them are active against serine and cysteine proteases, PIs active against aspartic proteases and carboxypeptidases have also been identified. Inhibitors of serine proteases are further classifiable in several families on the basis of their structural features. They comprise the families known as Bowman-Birk, Kunitz, Potato I and Potato II, which are the subject of review articles included in this special issue. In the present article we aim to give an overview of other families of plant PIs, active either against serine proteases or other class of proteases, describing their distribution, activity and main structural characteristics.

  16. Anti-breast cancer effects of histone deacetylase inhibitors and calpain inhibitor.

    PubMed

    Mataga, Megan A; Rosenthal, Shoshana; Heerboth, Sarah; Devalapalli, Amrita; Kokolus, Shannon; Evans, Leah R; Longacre, McKenna; Housman, Genevieve; Sarkar, Sibaji

    2012-07-01

    Development of new breast cancer therapies is needed, particularly as cells become refractory or develop increased drug resistance. In an effort to develop such treatments, class I and II histone deacetylases (HDACs), alone and in combination with other cytotoxic agents, are currently in clinical trial. Herein, we discuss the effects of histone deacetylase inhibitors (HDACi) when used in combination with calpeptin, an inhibitor of the regulatory protease, calpain. We present results of study in two breast cancer cells lines with distinct characteristics: MDA-MB-231 and MCF-7. When used in combination with calpeptin, two chemically distinct HDACi significantly inhibited growth and increased cell death by inducing cell-cycle arrest and apoptosis. MCF-7 cells exhibited a greater proportion of arrest at the G(1) phase, whereas triple-negative MDA-MB-231 cells exhibited increased cell cycle arrest at the S phase. Methylation of the imprinted and silenced proapoptoic tumor suppressor gene aplasia Ras homolog member I (ARHI) was reduced in both cell lines after treatment with HDACi. However, it was only re-expressed on such treatment in MDA-MB-231 cells, suggesting that re-expression operates under differential mechanisms in these two cell lines. Collectively, these results showed that the combination of HDACi and calpeptin inhibited the growth of two distinctly different types of breast cancer cells and could have wide clinical applications, though the mechanisms of inhibition are possibly different.

  17. EGFR inhibitors and autophagy in cancer treatment.

    PubMed

    Cui, Jie; Hu, Yun-Feng; Feng, Xie-Min; Tian, Tao; Guo, Ya-Huan; Ma, Jun-Wei; Nan, Ke-Jun; Zhang, Hong-Yi

    2014-12-01

    Epidermal growth factor receptor (EGFR) inhibitor treatment is a strategy for cancer therapy. However, innate and acquired resistance is a major obstacle of the efficacy. Autophagy is a self-digesting process in cells, which is considered to be associated with anti-cancer drug resistance. The activation of EGFR can regulate autophagy through multiple signal pathways. EGFR inhibitors can induce autophagy, but the specific function of the induction of autophagy by EGFR inhibitors remains biphasic. On the one hand, autophagy induced by EGFR inhibitors acts as a cytoprotective response in cancer cells, and autophagy inhibitors can enhance the cytotoxic effects of EGFR inhibitors. On the other hand, a high level of autophagy after treatment of EGFR inhibitors can also result in autophagic cell death lacking features of apoptosis, and the combination of EGFR inhibitors with an autophagy inducer might be beneficial. Thus, autophagy regulation represents a promising approach for improving the efficacy of EGFR inhibitors in the treatment of cancer patients.

  18. Identification of Novel Small Molecule Inhibitors of Oncogenic RET Kinase.

    PubMed

    Moccia, Marialuisa; Liu, Qingsong; Guida, Teresa; Federico, Giorgia; Brescia, Annalisa; Zhao, Zheng; Choi, Hwan Geun; Deng, Xianming; Tan, Li; Wang, Jinhua; Billaud, Marc; Gray, Nathanael S; Carlomagno, Francesca; Santoro, Massimo

    2015-01-01

    Oncogenic mutation of the RET receptor tyrosine kinase is observed in several human malignancies. Here, we describe three novel type II RET tyrosine kinase inhibitors (TKI), ALW-II-41-27, XMD15-44 and HG-6-63-01, that inhibit the cellular activity of oncogenic RET mutants at two digit nanomolar concentration. These three compounds shared a 3-trifluoromethyl-4-methylpiperazinephenyl pharmacophore that stabilizes the 'DFG-out' inactive conformation of RET activation loop. They blocked RET-mediated signaling and proliferation with an IC50 in the nM range in fibroblasts transformed by the RET/C634R and RET/M918T oncogenes. They also inhibited autophosphorylation of several additional oncogenic RET-derived point mutants and chimeric oncogenes. At a concentration of 10 nM, ALW-II-41-27, XMD15-44 and HG-6-63-01 inhibited RET kinase and signaling in human thyroid cancer cell lines carrying oncogenic RET alleles; they also inhibited proliferation of cancer, but not non-tumoral Nthy-ori-3-1, thyroid cells, with an IC50 in the nM range. The three compounds were capable of inhibiting the 'gatekeeper' V804M mutant which confers substantial resistance to established RET inhibitors. In conclusion, we have identified a type II TKI scaffold, shared by ALW-II-41-27, XMD15-44 and HG-6-63-01, that may be used as novel lead for the development of novel agents for the treatment of cancers harboring oncogenic activation of RET.

  19. Identification of Novel Small Molecule Inhibitors of Oncogenic RET Kinase

    PubMed Central

    Moccia, Marialuisa; Liu, Qingsong; Guida, Teresa; Federico, Giorgia; Brescia, Annalisa; Zhao, Zheng; Choi, Hwan Geun; Deng, Xianming; Tan, Li; Wang, Jinhua; Billaud, Marc; Gray, Nathanael S.

    2015-01-01

    Oncogenic mutation of the RET receptor tyrosine kinase is observed in several human malignancies. Here, we describe three novel type II RET tyrosine kinase inhibitors (TKI), ALW-II-41-27, XMD15-44 and HG-6-63-01, that inhibit the cellular activity of oncogenic RET mutants at two digit nanomolar concentration. These three compounds shared a 3-trifluoromethyl-4-methylpiperazinephenyl pharmacophore that stabilizes the ‘DFG-out’ inactive conformation of RET activation loop. They blocked RET-mediated signaling and proliferation with an IC50 in the nM range in fibroblasts transformed by the RET/C634R and RET/M918T oncogenes. They also inhibited autophosphorylation of several additional oncogenic RET-derived point mutants and chimeric oncogenes. At a concentration of 10 nM, ALW-II-41-27, XMD15-44 and HG-6-63-01 inhibited RET kinase and signaling in human thyroid cancer cell lines carrying oncogenic RET alleles; they also inhibited proliferation of cancer, but not non-tumoral Nthy-ori-3-1, thyroid cells, with an IC50 in the nM range. The three compounds were capable of inhibiting the ‘gatekeeper’ V804M mutant which confers substantial resistance to established RET inhibitors. In conclusion, we have identified a type II TKI scaffold, shared by ALW-II-41-27, XMD15-44 and HG-6-63-01, that may be used as novel lead for the development of novel agents for the treatment of cancers harboring oncogenic activation of RET. PMID:26046350

  20. ADMINISTRATION OF A SUBSTITUTED ADAMANTLY-UREA INHIBITOR OF THE SOLUBLE EPOXIDE HYDROLASE PROTECTS THE KIDNEY FROM DAMAGE IN HYPERTENSIVE GOTO-KAKIZAKI RATS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hypertension and type II diabetes are co-morbid diseases that lead to the development of nephropathy. Soluble epoxide hydrolase (sEH) inhibitors are reported to provide protection from renal injury. We hypothesized that the sEH inhibitor 12-(3-adamantan-1-yl-ureido) dodecanoic acid (AUDA) protects ...

  1. Parenteral administration of factor Xa/IIa inhibitors limits experimental aortic aneurysm and atherosclerosis

    PubMed Central

    Moran, Corey S.; Seto, Sai-Wang; Krishna, Smriti M.; Sharma, Surabhi; Jose, Roby J.; Biros, Erik; Wang, Yutang; Morton, Susan K.; Golledge, Jonathan

    2017-01-01

    Intraluminal thrombus is a consistent feature of human abdominal aortic aneurysm (AAA). Coagulation factor Xa (FXa) catalyses FII to thrombin (FIIa). We examined the effect of FXa/FIIa inhibition on experimental aortic aneurysm in apolipoprotein E-deficient (ApoE−/−) mice infused with angiotensin II (AngII). The concentration of FXa within the supra-renal aorta (SRA) correlated positively with SRA diameter. Parenteral administration of enoxaparin (FXa/IIa inhibitor) and fondaparinux (FXa inhibitor) over 14 days reduced to severity of aortic aneurysm and atherosclerosis in AngII-infused ApoE−/− mice. Enteral administration of the FIIa inhibitor dabigatran had no significant effect. Aortic protease-activated receptor (PAR)-2 expression increased in response to AngII infusion. Fondaparinux reduced SRA levels of FXa, FIIa, PAR-2, matrix metalloproteinase (MMP)2, Smad2/3 phosphorylation, and MOMA-2 positive cells in the mouse model. FXa stimulated Smad2/3 phosphorylation and MMP2 expression in aortic vascular smooth muscle cells (VSMC) in vitro. Expression of MMP2 in FXa-stimulated VSMC was downregulated in the presence of a PAR-2 but not a PAR-1 inhibitor. These findings suggest that FXa/FIIa inhibition limits aortic aneurysm and atherosclerosis severity due to down-regulation of vascular PAR-2-mediated Smad2/3 signalling and MMP2 expression. Inhibition of FXa/FIIa may be a potential therapy for limiting aortic aneurysm. PMID:28220880

  2. Parenteral administration of factor Xa/IIa inhibitors limits experimental aortic aneurysm and atherosclerosis.

    PubMed

    Moran, Corey S; Seto, Sai-Wang; Krishna, Smriti M; Sharma, Surabhi; Jose, Roby J; Biros, Erik; Wang, Yutang; Morton, Susan K; Golledge, Jonathan

    2017-02-21

    Intraluminal thrombus is a consistent feature of human abdominal aortic aneurysm (AAA). Coagulation factor Xa (FXa) catalyses FII to thrombin (FIIa). We examined the effect of FXa/FIIa inhibition on experimental aortic aneurysm in apolipoprotein E-deficient (ApoE(-/-)) mice infused with angiotensin II (AngII). The concentration of FXa within the supra-renal aorta (SRA) correlated positively with SRA diameter. Parenteral administration of enoxaparin (FXa/IIa inhibitor) and fondaparinux (FXa inhibitor) over 14 days reduced to severity of aortic aneurysm and atherosclerosis in AngII-infused ApoE(-/-) mice. Enteral administration of the FIIa inhibitor dabigatran had no significant effect. Aortic protease-activated receptor (PAR)-2 expression increased in response to AngII infusion. Fondaparinux reduced SRA levels of FXa, FIIa, PAR-2, matrix metalloproteinase (MMP)2, Smad2/3 phosphorylation, and MOMA-2 positive cells in the mouse model. FXa stimulated Smad2/3 phosphorylation and MMP2 expression in aortic vascular smooth muscle cells (VSMC) in vitro. Expression of MMP2 in FXa-stimulated VSMC was downregulated in the presence of a PAR-2 but not a PAR-1 inhibitor. These findings suggest that FXa/FIIa inhibition limits aortic aneurysm and atherosclerosis severity due to down-regulation of vascular PAR-2-mediated Smad2/3 signalling and MMP2 expression. Inhibition of FXa/FIIa may be a potential therapy for limiting aortic aneurysm.

  3. The synthesis and biological evaluation of a novel series of phthalazine PDE4 inhibitors I.

    PubMed

    Napoletano, M; Norcini, G; Pellacini, F; Marchini, F; Morazzoni, G; Ferlenga, P; Pradella, L

    2000-10-02

    This communication describes the synthesis and in vitro evaluation of a novel and potent series of phosphodiesterase type IV (PDE4) inhibitors. The compounds described represent conformationally constrained analogues of RP 73401, Piclamilast. Preliminary evidences of reduced side effects of II compared to standards are also reported.

  4. Arylphthalazines: identification of a new phthalazine chemotype as inhibitors of VEGFR kinase.

    PubMed

    Piatnitski, Evgueni L; Duncton, Matthew A J; Kiselyov, Alexander S; Katoch-Rouse, Reeti; Sherman, Dan; Milligan, Daniel L; Balagtas, Chris; Wong, Wai C; Kawakami, Joel; Doody, Jacqueline F

    2005-11-01

    A novel class of 4-arylamino-phthalazin-1-yl-benzamides is described as inhibitors of vascular endothelial growth factor receptor II (VEGFR-2). Several compounds display potent VEGFR-2 inhibitory activity with an IC50 as low as 0.078 microM in an HTRF enzymatic assay. These compounds are relatively selective against a small kinase panel.

  5. Recent Methodologies toward the Synthesis of Valdecoxib: A Potential 3,4-diarylisoxazolyl COX-2 Inhibitor

    PubMed Central

    Dadiboyena, Sureshbabu; Nefzi, Adel

    2011-01-01

    Non-steroidal anti-inflammatory drugs are widely used therapeutic agents in the treatment of inflammation, pain and fever. Cyclooxygenase catalyzes the initial step of biotransformation of arachidonic acid to prostanoids, and exist as three distinct isozymes; COX-I, COX-II and COX-III. Selective COX-II inhibitors are a class of potential anti-inflammatory, analgesic, and antipyretic drugs with reduced gastrointestinal (GI) side effects compared to nonselective inhibitors. 3,4-diarylisoxazole scaffold is recurrently found in a wide variety of NSAIDs, protein kinase inhibitors, hypertensive agents, and estrogen receptor (ER) modulators. In the present review, we document on the recent synthetic strategies of 3,4-diarylisoxazolyl scaffolds of valdecoxib and its relevant structural analogues. PMID:20724040

  6. Inhibitory effect of peroxiredoxin II (Prx II) on Ras-ERK-NFkappaB pathway in mouse embryonic fibroblast (MEF) senescence.

    PubMed

    Han, Ying-Hao; Kwon, Jeong-Hoon; Yu, Dae-Yeul; Moon, Eun-Yi

    2006-11-01

    Intracellular reactive oxygen species (ROS) were attenuated by the expression of peroxiredoxin II (Prx II). Cellular senescence as judged by senescence-associated (SA)-beta-galactosidase (Gal) positive cell formation was increased in Prx II-deficient mouse embryonic fibroblast (MEF). Ras expression was increased following passages. The level of Ras expression was higher in Prx II-/- MEF than wild type MEF. ERK activity was also augmented by the deletion of Prx II. SA-beta-Gal-positive cell formation was reduced by PD98059, ERK inhibitor. Activated nuclear transcription factor, nuclear factor-kappaB (NFkappaB) by the deletion of Prx II was inhibited by the treatment with PD98059. In contrast, no changes in SA-beta-Gal-positive cell formation were detected by NFkappaB inhibitor, N-alpha-tosyl-L-phenylalanyl chloromethyl ketone (TPCK). Collectively, results suggest that Prx II deletion activate Ras-ERK-NFkappaB pathways and cellular senescence in Prx II-/- MEF cells was mediated by ERK activation but not by NFkappaB activation.

  7. 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

  8. Benzimidazole derivatives as kinase inhibitors.

    PubMed

    Garuti, Laura; Roberti, Marinella; Bottegoni, Giovanni

    2014-01-01

    Benzimidazole is a common kinase inhibitor scaffold and benzimidazole-based compounds interact with enzymes by multiple binding modes. In some cases, the benzimidazole acts as part of the hinge-binding motif, in others it has a scaffolding role without evidence for direct hinge binding. Several of these compounds are ATP-competitive inhibitors and show high selectivity by exploiting unique structural properties that distinguish one kinase from the majority of other kinases. However, the high specificity for a single target is not always sufficient. Thus another approach, called multi-target therapy, has been developed over the last few years. The simultaneous inhibition of various kinases may be useful because the disease is attacked at several relevant targets. Moreover, if a kinase becomes drug-resistant, a multitargeted drug can act on the other kinases. Some benzimidazole derivatives are multi-target inhibitors. In this article benzimidazole inhibitors are reported with their mechanisms of action, structure-activity relationship (SAR) and biological properties.

  9. 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.

  10. Inhibitor Discovery by Convolution ABPP.

    PubMed

    Chandrasekar, Balakumaran; Hong, Tram Ngoc; van der Hoorn, Renier A L

    2017-01-01

    Activity-based protein profiling (ABPP) has emerged as a powerful proteomic approach to study the active proteins in their native environment by using chemical probes that label active site residues in proteins. Traditionally, ABPP is classified as either comparative or competitive ABPP. In this protocol, we describe a simple method called convolution ABPP, which takes benefit from both the competitive and comparative ABPP. Convolution ABPP allows one to detect if a reduced signal observed during comparative ABPP could be due to the presence of inhibitors. In convolution ABPP, the proteomes are analyzed by comparing labeling intensities in two mixed proteomes that were labeled either before or after mixing. A reduction of labeling in the mix-and-label sample when compared to the label-and-mix sample indicates the presence of an inhibitor excess in one of the proteomes. This method is broadly applicable to detect inhibitors in proteomes against any proteome containing protein activities of interest. As a proof of concept, we applied convolution ABPP to analyze secreted proteomes from Pseudomonas syringae-infected Nicotiana benthamiana leaves to display the presence of a beta-galactosidase inhibitor.

  11. [Is there an indication for the association of betablockers and angiotensin II receptor antagonists in cardiac failure?].

    PubMed

    Jondeau, G; Milleron, O; Morisson-Castagnet, J F

    2004-06-01

    ACE inhibitors initially developed as vasodilators are effective by their anti-hormonal action. Antagonists of the receptors of angiotensin II (ARA II) should provide an equivalent or better blockade of the rennin-angiotensin system (absence of tolerance). Clinical trials have shown equivalent haemodynamic effects of the two classes, equal functional tolerance but mortality studies have shown more variable results. None have shown the superiority of ARA II over ACE inhibitors and the demonstration of their equivalence has just been reported with high doses in the post-infarction period. A deleterious effect of ARA II in association with betablockers was reported in two mortality studies but has not been confirmed in the most recent trials. The difficulty is to determine the roles of the association of ARA II-ACE inhibitors, ARA II-antialdosterones or of the association of all three classes of molecules.

  12. Induction of histone deacetylases (HDACs) in human abdominal aortic aneurysm: therapeutic potential of HDAC inhibitors

    PubMed Central

    Galán, María; Varona, Saray; Orriols, Mar; Rodríguez, José Antonio; Aguiló, Silvia; Dilmé, Jaume; Camacho, Mercedes; Martínez-González, José; Rodriguez, Cristina

    2016-01-01

    ABSTRACT Clinical management of abdominal aortic aneurysm (AAA) is currently limited to elective surgical repair because an effective pharmacotherapy is still awaited. Inhibition of histone deacetylase (HDAC) activity could be a promising therapeutic option in cardiovascular diseases. We aimed to characterise HDAC expression in human AAA and to evaluate the therapeutic potential of class I and IIa HDAC inhibitors in the AAA model of angiotensin II (Ang II)-infused apolipoprotein-E-deficient (ApoE−/−) mice. Real-time PCR, western blot and immunohistochemistry evidenced an increased expression of HDACs 1, 2 (both class I), 4 and 7 (both class IIa) in abdominal aorta samples from patients undergoing AAA open repair (n=22) compared with those from donors (n=14). Aortic aneurysms from Ang-II-infused ApoE−/− mice exhibited a similar HDAC expression profile. In these animals, treatment with a class I HDAC inhibitor (MS-275) or a class IIa inhibitor (MC-1568) improved survival, reduced the incidence and severity of AAA and limited aneurysmal expansion evaluated by Doppler ultrasonography. These beneficial effects were more potent in MC-1568-treated mice. The disorganisation of elastin and collagen fibres and lymphocyte and macrophage infiltration were effectively reduced by both inhibitors. Additionally, HDAC inhibition attenuated the exacerbated expression of pro-inflammatory markers and the increase in metalloproteinase-2 and -9 activity induced by Ang II in this model. Therefore, our data evidence that HDAC expression is deregulated in human AAA and that class-selective HDAC inhibitors limit aneurysm expansion in an AAA mouse model. New-generation HDAC inhibitors represent a promising therapeutic approach to overcome human aneurysm progression. PMID:26989193

  13. Synthesis of antifungal glucan synthase inhibitors from enfumafungin.

    PubMed

    Zhong, Yong-Li; Gauthier, Donald R; Shi, Yao-Jun; McLaughlin, Mark; Chung, John Y L; Dagneau, Philippe; Marcune, Benjamin; Krska, Shane W; Ball, Richard G; Reamer, Robert A; Yasuda, Nobuyoshi

    2012-04-06

    An efficient, new, and scalable semisynthesis of glucan synthase inhibitors 1 and 2 from the fermentation product enfumafungin 3 is described. The highlights of the synthesis include a high-yielding ether bond-forming reaction between a bulky sulfamidate 17 and alcohol 4 and a remarkably chemoselective, improved palladium(II)-mediated Corey-Yu allylic oxidation at the highly congested C-12 position of the enfumafungin core. Multi-hundred gram quantities of the target drug candidates 1 and 2 were prepared, in 12 linear steps with 25% isolated yield and 13 linear steps with 22% isolated yield, respectively.

  14. Synthesis of hydroxypyrone- and hydroxythiopyrone-based matrix metalloproteinase inhibitors: Developing a structure–activity relationship

    PubMed Central

    Yan, Yi-Long; Miller, Melissa T.; Cao, Yuchen; Cohen, Seth M.

    2010-01-01

    The zinc(II)-dependent matrix metalloproteinases (MMPs) are associated with a variety of diseases. Development of inhibitors to modulate MMP activity has been an active area of investigation for therapeutic development. Hydroxypyrones and hydroxythiopyrones are alternative zinc-binding groups (ZBGs) that, when combined with peptidomimetic backbones, comprise a novel class of MMP inhibitors (MMPi). In this report, a series of hydroxypyrone- and hydroxythiopyrone-based MMPi with aryl backbones at the 2-, 5-, and 6-positions of the hydroxypyrone ring have been synthesized. Synthetic routes for developing inhibitors with substituents at two of these positions (so-called double-handed inhibitors) are also explored. The MMP inhibition profiles and structure–activity relationship of synthesized hydroxypyrones and hydroxythiopyrones have been analyzed. The results here show that the ZBG, the position of the backbone on the ZBG, and the nature of the linker between the ZBG and backbone are critical for MMPi activities. PMID:19261472

  15. Tyrosine Kinase Inhibitors and Vascular Toxicity: Impetus for a Classification System?

    PubMed

    Herrmann, Joerg

    2016-06-01

    The introduction of molecularly targeted therapies with tyrosine kinase inhibitors has revolutionized cancer therapy and has contributed to a steady decline in cancer-related mortality since the late 1990s. However, not only cardiac but also vascular toxicity has been reported for these agents, some as expected on-target effects (e.g., VEGF receptor inhibitors) and others as unanticipated events (e.g., BCR-Abl inhibitors). A sound understanding of these cardiovascular toxic effects is critical to advance mechanistic insight into vascular disease and clinical care. From a conceptual standpoint, there might be value in defining type I (permanent) and type II (transient) vascular toxicity. This review will focus on the tyrosine kinase inhibitors in current clinical use and their associated vascular side effects.

  16. DNA damage response to the Mdm2 inhibitor Nutlin-3

    PubMed Central

    Verma, Rajeev; Rigatti, Marc J.; Belinsky, Glenn S.; Godman, Cassandra A.; Giardina, Charles

    2009-01-01

    Mdm2 inhibitors represent a promising class of p53 activating compounds that may be useful in cancer treatment and prevention. However, the consequences of pharmacological p53 activation are not entirely clear. We observed that Nutlin-3 triggered a DNA damage response in azoxymethane-induced mouse AJ02-NM0 colon cancer cells, characterized by the phosphorylation of H2AX (at Ser-139) and p53 (at Ser-15). The DNA damage response was highest in cells showing robust p53 stabilization, it could be triggered by the active but not the inactive Nutlin-3 enantiomer, and it was also activated by another pharmacological Mdm2 inhibitor (Caylin). Quantification of γH2AX-positive cells following Nutlin-3 exposure showed that approximately 17% of cells in late S and G2/M were mounting a DNA damage response (compared to a ~50% response to 5-fluorouracil). Nutlin-3 treatment caused the formation of double strand DNA strand breaks, promoted the formation of micronuclei, accentuated strand breakage induced by doxorubicin and sensitized the mouse colon cancer cells to DNA break-inducing topoisomerase II inhibitors. Although the HCT116 colon cancer cells did not mount a significant DNA damage response following Nutlin-3 treatment, Nutlin-3 enhanced the DNA damage response to the nucleotide synthesis inhibitor hydroxyurea in a p53-dependent manner. Finally, p21 deletion also sensitized HCT116 cells to the Nutlin-3-induced DNA damage response, suggesting that cell cycle checkpoint abnormalities may promote this response. We propose that p53 activation by Mdm2 inhibitors can result in the slowing of double stranded DNA repair. Although this effect may suppress illegitimate homologous recombination repair, it may also increase the risk of clastogenic events. PMID:19788889

  17. Cathepsin D inhibitor from Vicia sativa L.

    PubMed

    Roszkowska-Jakimiec, W; Bańkowska, A

    1998-01-01

    Specific inhibitor of cathepsin D has been shown in the extract of Vicia sativa L. seeds. This inhibitor does not inhibit the activity of other aspartic proteases. Also it does not inhibit the activity of cysteine proteases and serine proteases.

  18. Kinase inhibitor profile for human nek1, nek6, and nek7 and analysis of the structural basis for inhibitor specificity.

    PubMed

    Moraes, Eduardo Cruz; Meirelles, Gabriela Vaz; Honorato, Rodrigo Vargas; de Souza, Tatiana de Arruda Campos Brasil; de Souza, Edmarcia Elisa; Murakami, Mario Tyago; de Oliveira, Paulo Sergio Lopes; Kobarg, Jörg

    2015-01-13

    Human Neks are a conserved protein kinase family related to cell cycle progression and cell division and are considered potential drug targets for the treatment of cancer and other pathologies. We screened the activation loop mutant kinases hNek1 and hNek2, wild-type hNek7, and five hNek6 variants in different activation/phosphorylation statesand compared them against 85 compounds using thermal shift denaturation. We identified three compounds with significant Tm shifts: JNK Inhibitor II for hNek1(Δ262-1258)-(T162A), Isogranulatimide for hNek6(S206A), andGSK-3 Inhibitor XIII for hNek7wt. Each one of these compounds was also validated by reducing the kinases activity by at least 25%. The binding sites for these compounds were identified by in silico docking at the ATP-binding site of the respective hNeks. Potential inhibitors were first screened by thermal shift assays, had their efficiency tested by a kinase assay, and were finally analyzed by molecular docking. Our findings corroborate the idea of ATP-competitive inhibition for hNek1 and hNek6 and suggest a novel non-competitive inhibition for hNek7 in regard to GSK-3 Inhibitor XIII. Our results demonstrate that our approach is useful for finding promising general and specific hNekscandidate inhibitors, which may also function as scaffolds to design more potent and selective inhibitors.

  19. Purification and inhibitory profile of phospholipase A2 inhibitors from Australian elapid sera.

    PubMed Central

    Hains, P G; Broady, K W

    2000-01-01

    Although the resistance of snakes to their own venom is well known, until now no investigators have examined the serum of Australian snakes. Here we describe the identification and purification of a range of phospholipase A(2) (PLA(2)) inhibitors from the serum of Australian elapids. All PLA(2) inhibitors were composed of two protein chains, an alpha-chain and a beta-chain. The alpha-chains were approx. 22.5 kDa in size and variably glycosylated, whereas the beta-chains were approx. 19.8 kDa in size and not glycosylated. Identification of isoforms of the two subunit chains was significant because three of the six sera examined were from single snake specimens. In addition, the glycosylation patterns of the alpha-chains were thoroughly investigated in these unpooled sera. The functional and structural properties of the purified inhibitors were studied. Uniquely, a snake PLA(2) inhibitor was found to inhibit human type II PLA(2) enzyme, which has implications for the treatment of the many diseases in which PLA(2) enzymes have been implicated. Further, we demonstrate that the inhibitor forms a non-covalent association with a purified PLA(2) enzyme. Finally, the purified PLA(2) inhibitor was shown to protect in vivo against the lethal affects of a homologous PLA(2) enzyme, suggesting a role for PLA(2) inhibitors in the treatment of snake bite victims. PMID:10657250

  20. Mechanisms for autophagy modulation by isoprenoid biosynthetic pathway inhibitors in multiple myeloma cells.

    PubMed

    Dykstra, Kaitlyn M; Allen, Cheryl; Born, Ella J; Tong, Huaxiang; Holstein, Sarah A

    2015-12-08

    Multiple myeloma (MM) is characterized by the production of monoclonal protein (MP). We have shown previously that disruption of the isoprenoid biosynthetic pathway (IBP) causes a block in MP secretion through a disruption of Rab GTPase activity, leading to an enhanced unfolded protein response and subsequent apoptosis in MM cells. Autophagy is induced by cellular stressors including nutrient deprivation and ER stress. IBP inhibitors have been shown to have disparate effects on autophagy. Here we define the mechanisms underlying the differential effects of IBP inhibitors on autophagic flux in MM cells utilizing specific pharmacological inhibitors. We demonstrate that IBP inhibition induces a net increase in autophagy as a consequence of disruption of isoprenoid biosynthesis which is not recapitulated by direct geranylgeranyl transferase inhibition. IBP inhibitor-induced autophagy is a cellular defense mechanism as treatment with the autophagy inhibitor bafilomycin A1 enhances the cytotoxic effects of GGPP depletion, but not geranylgeranyl transferase inhibition. Immunofluorescence microscopy studies revealed that IBP inhibitors disrupt ER to Golgi trafficking of monoclonal light chain protein and that this protein is not a substrate for alternative degradative pathways such as aggresomes and autophagosomes. These studies support further development of specific GGTase II inhibitors as anti-myeloma agents.

  1. X-ray Crystallographic Studies Reveal That the Incorporation of Spacer Groups in Carbonic Anhydrase Inhibitors Causes Alternate Binding Modes

    SciTech Connect

    Fisher,S.; Govindasamy, L.; Boyle, N.; Agbandje-McKenna, M.; Silverman, D.; Blackburn, G.; McKenna, R.

    2006-01-01

    Human carbonic anhydrases (CAs) are well studied targets for the development of inhibitors for pharmaceutical applications. The crystal structure of human CA II has been determined in complex with two CA inhibitors (CAIs) containing conventional sulfonamide and thiadiazole moieties separated by a -CF{sub 2}- or -CHNH{sub 2}- spacer group. The structures presented here reveal that these spacer groups allow novel binding modes for the thiadiazole moiety compared with conventional CAIs.

  2. Inhibitors of human heart chymase based on a peptide library.

    PubMed Central

    Bastos, M; Maeji, N J; Abeles, R H

    1995-01-01

    We have synthesized two sets of noncleavable peptide-inhibitor libraries to map the S and S' subsites of human heart chymase. Human heart chymase is a chymotrypsin-like enzyme that converts angiotensin I to angiotensin II. The first library consists of peptides with 3-fluorobenzylpyruvamides in the P1 position. (Amino acid residues of substrates numbered P1, P2, etc., are toward the N-terminal direction, and P'1, P'2, etc., are toward the C-terminal direction from the scissile bond.) The P'1 and P'2 positions were varied to contain each one of the 20 naturally occurring amino acids and P'3 was kept constant as an arginine. The second library consists of peptides with phenylalanine keto-amides at P1, glycine in P'1, and benzyloxycarbonyl (Z)-isoleucine in P4. The P2 and P3 positions were varied to contain each of the naturally occurring amino acids, except for cysteine and methionine. The peptides of both libraries are attached to a solid support (pins). The peptides are evaluated by immersing the pins in a solution of the target enzyme and evaluating the amount of enzyme absorbed. The pins with the best inhibitors will absorb most enzyme. The libraries select the best and worst inhibitors within each group of peptides and provide an approximate ranking of the remaining peptides according to Ki. Through this library, we determined that Z-Ile-Glu-Pro-Phe-CO2Me and (F)-Phe-CO-Glu-Asp-ArgOMe should be the best inhibitors of chymase in this collection of peptide inhibitors. We synthesized the peptides and found Ki values were 1 nM and 1 microM, respectively. The corresponding Ki values for chymotrypsin were 10 nM and 100 microM. The use of libraries of inhibitors has advantages over the classical method of synthesis of potential inhibitors in solution: the libraries are reusable, the same libraries can be used with a variety of different serine proteases, and the method allows the screening of hundreds of compounds in short periods of time. Images Fig. 1 PMID:7624313

  3. Small-molecule arginase inhibitors.

    PubMed

    Ivanenkov, Yan A; Chufarova, Nina V

    2014-01-01

    Arginase is an enzyme that metabolizes L-arginine to L-ornithine and urea. In addition to its fundamental role in the hepatic ornithine cycle, it also influences the immune systems in humans and mice. Arginase participates in many inflammatory disorders by decreasing the synthesis of nitric oxide and inducing fibrosis and tissue regeneration. L-arginine deficiency, which is modulated by myeloid cell arginase, suppresses T-cell immune response. This mechanism plays a fundamental role in inflammation-associated immunosuppression. Pathogens can synthesize their own arginase to elude immune reaction. Small-molecule arginase inhibitors are currently described as promising therapeutics for the treatment of several diseases, including allergic asthma, inflammatory bowel disease, ulcerative colitis, cardiovascular diseases (atherosclerosis and hypertension), diseases associated with pathogens (e.g., Helicobacter pylori, Trypanosoma cruzi, Leishmania, Mycobacterium tuberculosis and Salmonella), cancer and induced or spontaneous immune disorders. This article summarizes recent patents in the area of arginase inhibitors and discusses their properties.

  4. 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

  5. Salicylanilide inhibitors of Toxoplasma gondii.

    PubMed

    Fomovska, Alina; Wood, Richard D; Mui, Ernest; Dubey, Jitenter P; Ferreira, 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

    2012-10-11

    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 antiapicomplexan 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.

  6. Sibling rivalry: competition between MHC class II family members inhibits immunity.

    PubMed

    Denzin, Lisa K; Cresswell, Peter

    2013-01-01

    Peptide loading of major histocompatibility complex (MHC) class II molecules in the endosomes and lysosomes of antigen-presenting cells is catalyzed by human leukocyte antigen-DM (HLA-DM) and modulated by HLA-DO. In a structural study in this issue, Guce et al. show that HLA-DO is an MHC class II mimic and functions as a competitive and essentially irreversible inhibitor of HLA-DM activity, thereby inhibiting MHC class II antigen presentation.

  7. Recent progress on fucosyltransferase inhibitors.

    PubMed

    Merino, Pedro; Tejero, Tomás; Delso, Ignacio; Hurtado-Guerrero, Ramon; Gómez-SanJuan, Asier; Sádaba, David

    2012-12-01

    Fucosyltransferases (FucTs) are enzymes that transfer L-fucose from GDP-fucose to a glycoside or a peptide. They have important roles in a variety of diseases including cancer and autoimmune disorders, viral and bacterial infections and inflammatory processes, and thus they represent important drug targets for the development of agents for the treatment of such disorders. This review highlights recent developments regarding carbohydrate mimics as inhibitors of FucTs. The most recent and relevant synthetic strategies are described.

  8. Nelfinavir: fourth protease inhibitor approved.

    PubMed

    1997-01-01

    The Food and Drug Administration (FDA) has granted accelerated approval to nelfinavir in both adult and pediatric formulations. Agouron, the manufacturer, used innovative computerized drug design techniques to discover, design, and refine the nelfinavir molecule. Nelfinavir is marketed under the trade name Viracept, and costs $5,000 per year. Early clinical trials find it to be as powerful as the other protease inhibitors, but with a different resistance profile. The drug has relatively few drug indications; however, several compounds have been contraindicated.

  9. Voglibose: An Alpha Glucosidase Inhibitor

    PubMed Central

    Dabhi, Ajay S.; Bhatt, Nikita R.; Shah, Mohit J.

    2013-01-01

    Diabetes Mellitus (DM) is a morbid disease worldwide, with increasing incidence as time passes. It has macro-vascular and micro-vascular complications. The main cause of these complications is poorly controlled postprandial hyperglycaemia. Alpha glucosidase inhibitors, namely acarbose, voglibose and miglitol, are available for therapy. Voglibose is well tolerated and effective in comparable doses among these drugs. This article highlights the important features of voglibose. PMID:24551718

  10. Kinase Inhibitors from Marine Sponges

    PubMed Central

    Skropeta, Danielle; Pastro, Natalie; Zivanovic, Ana

    2011-01-01

    Protein kinases play a critical role in cell regulation and their deregulation is a contributing factor in an increasing list of diseases including cancer. Marine sponges have yielded over 70 novel compounds to date that exhibit significant inhibitory activity towards a range of protein kinases. These compounds, which belong to diverse structural classes, are reviewed herein, and ordered based upon the kinase that they inhibit. Relevant synthetic studies on the marine natural product kinase inhibitors have also been included. PMID:22073013

  11. 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.

  12. Substituted androstanes as aromatase inhibitors

    NASA Astrophysics Data System (ADS)

    Levina, Inna S.

    1998-11-01

    The synthesis and structure-activity relationships of inhibitors of steroid aromatase which catalyses the last stage of a multistep biotransformation of cholesterol into estrogens, viz., aromatisation of C19-steroids into C18-phenolic steroids, are discussed. Compounds of the androstane series which are structurally related to the natural substrate, viz., androst-4-ene-3,17-dione, are the subjects of consideration. The review encompasses problems of synthesis of various substituted androstanes and their aromatase-inhibiting activities and structural requirements for selective specific aromatase inhibitors based on in vitro and in vivo structure-activity studies of compounds synthesised, their biological properties and the results of clinical trials. Special attention is paid to practical applications of aromatase inhibitors in the treatment of hormone-dependent mammary and ovarian tumours as well as benign prostatic tumours. In writing this report, the author has used all the information currently available in the chemical, biochemical, endocrinological and medicinal literature as well as in patents. The bibliography includes 173 references.

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

    MedlinePlus

    ... Cancer Risk and Prevention Aromatase Inhibitors 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 ...

  14. Angiotensin II induces MMP 2 activity via FAK/JNK pathway in human endothelial cells.

    PubMed

    Jiménez, Eugenio; Pérez de la Blanca, Enrique; Urso, Loredana; González, Irene; Salas, Julián; Montiel, Mercedes

    2009-03-20

    Matrix metalloproteinases (MMPs) play an important role in the pathogenesis of cardiovascular diseases and are modified in response to a variety of stimuli such as bioactive peptides, cytokines and/or grown factors. In this study, we demonstrated that angiotensin II (Ang II) induces a time- and dose-dependent increase in the activity of metalloproteinase 2 (MMP 2) in human umbilical vein endothelial cells (HUVEC). The effect of Ang II was markedly attenuated in cells pretreated with wortmannin and LY294002, two selective inhibitors of phosphatidylinositol-3-kinase (PI3K), indicating that PI3K plays a key role in regulating MMP 2 activity. Similar results were observed when HUVEC were pretreated with genistein, a non-selective tyrosine kinases inhibitor, or with the specific Src-family tyrosine kinase inhibitor PP2, demonstrating the involvement of protein tyrosine kinases, and particularly Src-family tyrosine kinases on the downstream signaling pathway of Ang II receptors. Furthermore, Ang II-induced MMP 2 activation was markedly blocked by SP600125, a selective c-Jun N-terminal kinase (JNK) inhibitor, or pre-treatment of cells with antisense oligonucleotide to focal adhesion kinase (FAK), indicating that both molecules were important for the activation of MMP 2 by Ang II receptor stimulation. In conclusion, these results suggest that Ang II mediates an increase in MMP 2 activity in macrovascular endothelial cells through signal transduction pathways dependent on PI3K and Src-family tyrosine kinases activation, as well as JNK and FAK phosphorylation.

  15. [Phosphodiesterase-5 inhibitors for the treatment of pulmonary arterial hypertension].

    PubMed

    Beltrán-Gámez, Miguel E; Sandoval-Zárate, Julio; Pulido, Tomás

    2015-01-01

    In experimental and clinical cardiology, phosphodiesterase type 5 (PDE-5) inhibitors have brought scientific interest as a therapeutic tool in pulmonary arterial hypertension (PAH) management in recent years. Phosphodiesterases are a superfamily of enzymes that inactivate cyclic adenosine monophosphate and cyclic guanosine monophosphate, the second messengers of prostacyclin and nitric oxide. The rationale for the use of PDE-5 inhibitors in PAH is based on their capacity to overexpresss the nitric oxide pathway pursued inhibition of cyclic guanosine monophosphate hydrolysis. By increasing cyclic guanosine monophosphate levels it promotes vasodilation, antiproliferative and pro-apoptotic effects that may reverse pulmonary vascular remodeling. There is also evidence that these drugs may directly enhance right ventricular contractility through an increase in cyclic adenosine monophosphate mediated by the inhibition of the cyclic guanosine monophosphate -sensitive PDE-3. Sildenafil, tadalafil and vardenafil are 3 specific PDE-5 inhibitors in current clinical use, which share similar mechanisms of action but present some significant differences regarding potency, selectivity for PDE-5 and pharmacokinetic properties. Sildenafil received approval in 2005 by the Food and Drug Administration and the European Medicines Agency and tadalafil in 2009 by the Food and Drug Administration and the European Medicines Agency for the treatment of PAH in patients classified as NYHA/WHO functional class II and III. In Mexico, sildenafil and tadalafil were approved by Comisión Federal de Protección contra Riesgos Sanitarios for this indication in 2010 and 2011, respectively.

  16. Antidiabetic Indian Plants: A Good Source of Potent Amylase Inhibitors

    PubMed Central

    Bhat, Menakshi; Zinjarde, Smita S.; Bhargava, Shobha Y.; Kumar, Ameeta Ravi; Joshi, Bimba N.

    2011-01-01

    Diabetes is known as a multifactorial disease. The treatment of diabetes (Type II) is complicated due to the inherent patho-physiological factors related to this disease. One of the complications of diabetes is post-prandial hyperglycemia (PPHG). Glucosidase inhibitors, particularly α-amylase inhibitors are a class of compounds that helps in managing PPHG. Six ethno-botanically known plants having antidiabetic property namely, Azadirachta indica Adr. Juss.; Murraya koenigii (L.) Sprengel; Ocimum tenuflorum (L.) (syn: Sanctum); Syzygium cumini (L.) Skeels (syn: Eugenia jambolana); Linum usitatissimum (L.) and Bougainvillea spectabilis were tested for their ability to inhibit glucosidase activity. The chloroform, methanol and aqueous extracts were prepared sequentially from either leaves or seeds of these plants. It was observed that the chloroform extract of O. tenuflorum; B. spectabilis; M. koenigii and S. cumini have significant α-amylase inhibitory property. Plants extracts were further tested against murine pancreatic, liver and small intestinal crude enzyme preparations for glucosidase inhibitory activity. The three extracts of O. tenuflorum and chloroform extract of M. koenigi showed good inhibition of murine pancreatic and intestinal glucosidases as compared with acarbose, a known glucosidase inhibitor. PMID:18955350

  17. Methylation inhibitor therapy in the treatment of myelodysplastic syndrome.

    PubMed

    Silverman, Lewis R; Mufti, Ghulam J

    2005-12-01

    The class of DNA methyltransferase inhibitors is represented by azacitidine and decitabine. Azacitidine is approved for the treatment of patients in both low- and high-risk subtypes of myelodysplastic syndrome (MDS), and decitabine is currently under review by the FDA. Azacitidine phase III trial data, based upon the Cancer and Leukemia Group B (CALGB) study 9221, showed durable clinical and symptomatic improvement in bone marrow function, a reduction in the risk of leukemic transformation, and significant improvements in the quality of life of patients treated with azacitidine compared with supportive care alone. This study also provided data suggestive of improvement in survival in MDS patients. The experience with decitabine comprises a number of phase I/II studies and a phase III trial yet to be published. While there is a strong base of experience supporting the efficacy of DNA methyltransferase inhibitors in the treatment of MDS, a number of practical issues need to be explored further. These include the optimization of the timing and duration of treatment, and the prediction of response to therapy. Along with current experience, future studies will lead to the development of treatment algorithms, strategies for selecting patients (e.g. according to age, risk, classification, and cytogenetic profile), and the combination strategies, particularly with histone deacetylase inhibitors, in the management of MDS.

  18. Histone deacetylase inhibitors induce autophagy through FOXO1-dependent pathways.

    PubMed

    Zhang, Jianbin; Ng, Shukie; Wang, Jigang; Zhou, Jing; Tan, Shi-Hao; Yang, Naidi; Lin, Qingsong; Xia, Dajing; Shen, Han-Ming

    2015-04-03

    Autophagy is a catabolic process in response to starvation or other stress conditions to sustain cellular homeostasis. At present, histone deacetylase inhibitors (HDACIs) are known to induce autophagy in cells through inhibition of mechanistic target of rapamycin (MTOR) pathway. FOXO1, an important transcription factor regulated by AKT, is also known to play a role in autophagy induction. At present, the role of FOXO1 in the HDACIs-induced autophagy has not been reported. In this study, we first observed that HDACIs increased the expression of FOXO1 at the mRNA and protein level. Second, we found that FOXO1 transcriptional activity was enhanced by HDACIs, as evidenced by increased FOXO1 nuclear accumulation and transcriptional activity. Third, suppression of FOXO1 function by siRNA knockdown or by a chemical inhibitor markedly blocked HDACIs-induced autophagy. Moreover, we found that FOXO1-mediated autophagy is achieved via its transcriptional activation, leading to a dual effect on autophagy induction: (i) enhanced expression of autophagy-related (ATG) genes, and (ii) suppression of MTOR via transcription of the SESN3 (sestrin 3) gene. Finally, we found that inhibition of autophagy markedly enhanced HDACIs-mediated cell death, indicating that autophagy serves as an important cell survival mechanism. Taken together, our studies reveal a novel function of FOXO1 in HDACIs-mediated autophagy in human cancer cells and thus support the development of a novel therapeutic strategy by combining HDACIs and autophagy inhibitors in cancer therapy.

  19. Investigating the selectivity of metalloenzyme inhibitors.

    PubMed

    Day, Joshua A; Cohen, Seth M

    2013-10-24

    The inhibitory activity of a broad group of known metalloenzyme inhibitors against a panel of metalloenzymes was evaluated. Clinically approved inhibitors were selected as well as several other reported metalloprotein inhibitors in order to represent a broad range of metal binding groups (MBGs), including hydroxamic acid, carboxylate, hydroxypyridinonate, thiol, and N-hydroxyurea functional groups. A panel of metalloenzymes, including carbonic anhydrase (hCAII), several matrix metalloproteinases (MMPs), angiotensin converting enzyme (ACE), histone deacetylase (HDAC-2), and tyrosinase (TY), was selected based on their clinical importance for a range of pathologies. In addition, each inhibitor was evaluated for its ability to remove Fe(3+) from holo-transferrin to gauge the ability of the inhibitors to access Fe(3+) from a primary transport protein. The results show that the metalloenzyme inhibitors are quite selective for their intended targets, suggesting that despite their ability to bind metal ions, metalloprotein inhibitors are not prone to widespread off-target enzyme inhibition activity.

  20. Isolation and purification of trypsin inhibitors from the seeds of Abelmoschus moschatus L.

    PubMed

    Dokka, Muni Kumar; Seva, Lavanya; Davuluri, Siva Prasad

    2015-04-01

    Four trypsin inhibitors, AMTI-I, AMTI-II, AMTI-III, and AMTI-IV, have been isolated and purified to homogeneity from the seeds of Abelmoschus moschatus following ammonium sulphate fractionation, DEAE-cellulose ion exchange chromatography and gel permeation on Sephadex G-100, and their molecular weights were determined to be 22.4, 21.2, 20.8 and 20.2 kDa respectively by SDS-PAGE. While all the four inhibitors were very active against bovine trypsin, two of them (AMTI-III and AMTI-IV) showed moderate activity towards bovine chymotrypsin. AMTI-I and AMTI-II were found to be glycoproteins with neutral sugar content of 2.8 and 4 %, respectively, and all the four inhibitors were devoid of free sulphhydryl groups. The inhibitors were quite stable up to 80 °C for 10 min and were not affected at alkaline as well as acidic conditions tested. Treating them with 8 M urea and 1 % SDS for 24 h at room temperature did not result in any loss of their antitryptic activities. However, they lost considerable antitryptic activity when treated with 6 M guanidine hydrochloride. Activities of the inhibitors were unaffected even after their reduction with DTT suggesting that disulphide bonds are not needed for their inhibitory activities.

  1. Novel inhibitor cystine knot peptides from Momordica charantia.

    PubMed

    He, Wen-Jun; Chan, Lai Yue; Clark, Richard J; Tang, Jun; Zeng, Guang-Zhi; Franco, Octavio L; Cantacessi, Cinzia; Craik, David J; Daly, Norelle L; Tan, Ning-Hua

    2013-01-01

    Two new peptides, MCh-1 and MCh-2, along with three known trypsin inhibitors (MCTI-I, MCTI-II and MCTI-III), were isolated from the seeds of the tropical vine Momordica charantia. The sequences of the peptides were determined using mass spectrometry and NMR spectroscopy. Using a strategy involving partial reduction and stepwise alkylation of the peptides, followed by enzymatic digestion and tandem mass spectrometry sequencing, the disulfide connectivity of MCh-1 was elucidated to be CysI-CysIV, CysII-CysV and CysIII-CysVI. The three-dimensional structures of MCh-1 and MCh-2 were determined using NMR spectroscopy and found to contain the inhibitor cystine knot (ICK) motif. The sequences of the novel peptides differ significantly from peptides previously isolated from this plant. Therefore, this study expands the known peptide diversity in M. charantia and the range of sequences that can be accommodated by the ICK motif. Furthermore, we show that a stable two-disulfide intermediate is involved in the oxidative folding of MCh-1. This disulfide intermediate is structurally homologous to the proposed ancestral fold of ICK peptides, and provides a possible pathway for the evolution of this structural motif, which is highly prevalent in nature.

  2. Inhibitors

    MedlinePlus

    ... Mutation Project (CHAMP) mutation list: a new online resource. Human Mutation. 2012; E2382-E2392. Li T, Miller CH, Payne AB, Hooper CW. The CDC Hemophilia B mutation project mutation list: a new online resource. Molecular Genetics and Genomic Medicine. 2013; 1(4): ...

  3. Depressor effect of chymase inhibitor in mice with high salt-induced moderate hypertension.

    PubMed

    Devarajan, Sankar; Yahiro, Eiji; Uehara, Yoshinari; Habe, Shigehisa; Nishiyama, Akira; Miura, Shin-ichiro; Saku, Keijiro; Urata, Hidenori

    2015-12-01

    The aim of the present study was to determine whether long-term high salt intake in the drinking water induces hypertension in wild-type (WT) mice and whether a chymase inhibitor or other antihypertensive drugs could reverse the increase of blood pressure. Eight-week-old male WT mice were supplied with drinking water containing 2% salt for 12 wk (high-salt group) or high-salt drinking water plus an oral chymase inhibitor (TPC-806) at four different doses (25, 50, 75, or 100 mg/kg), captopril (75 mg/kg), losartan (100 mg/kg), hydrochlorothiazide (3 mg/kg), eplerenone (200 mg/kg), or amlodipine (6 mg/kg). Control groups were given normal water with or without the chymase inhibitor. Blood pressure and heart rate gradually showed a significant increase in the high-salt group, whereas a dose-dependent depressor effect of the chymase inhibitor was observed. There was also partial improvement of hypertension in the losartan- and eplerenone-treated groups but not in the captopril-, hydrochlorothiazide-, and amlodipine-treated groups. A high salt load significantly increased chymase-dependent ANG II-forming activity in the alimentary tract. In addition, the relative contribution of chymase to ANG II formation, but not actual average activity, showed a significant increase in skin and skeletal muscle, whereas angiotensin-converting enzyme-dependent ANG II-forming activity and its relative contribution were reduced by high salt intake. Plasma and urinary renin-angiotensin system components were significantly increased in the high-salt group but were significantly suppressed in the chymase inhibitor-treated group. In conclusion, 2% salt water drinking for 12 wk caused moderate hypertension and activated the renin-angiotensin system in WT mice. A chymase inhibitor suppressed both the elevation of blood pressure and heart rate, indicating a definite involvement of chymase in salt-sensitive hypertension.

  4. Ovarian Cancer Stage II

    MedlinePlus

    ... Download Title: Ovarian Cancer Stage II Description: Three-panel drawing of stage IIA, IIB, and stage II primary peritoneal cancer; the first panel (stage IIA) shows cancer inside both ovaries that ...

  5. Factor II deficiency

    MedlinePlus

    ... if one or more of these factors are missing or are not functioning like they should. Factor II is one such coagulation factor. Factor II deficiency runs in families (inherited) and is very rare. Both parents must ...

  6. Cyclo-oxygenase-2 inhibitors: when should they be used in the elderly?

    PubMed

    Savage, Ruth

    2005-01-01

    result in loss of control of anticoagulation, and those with ACE inhibitors, angiotensin II type 1 receptor antagonists and diuretics, which can result in loss of control of blood pressure and cardiac failure and, in hypovolaemic conditions, renal failure. The clinical significance of an interaction between celecoxib and aspirin to reduce the antiplatelet effect of the latter drug is unknown. Preliminary information from spontaneous reporting systems indicates that there may be differences in the risk of cardiac failure and hypertension between standard NSAIDs and COX-2 inhibitors and between rofecoxib and celecoxib. More formal studies using equivalent doses are needed to test this observation. Use of COX-2 inhibitors may be considered in the elderly to reduce the risk of gastroduodenal complications associated with standard NSAIDs but only when consideration has first been given to use of less toxic medicines as alternatives or supplements, the appropriate dose of the COX-2 inhibitor or standard NSAID, the presence and possible impact of co-morbidities, and the implications of taking COX-2 inhibitors with any concomitant medications. Equally important is regular monitoring of the patient taking a COX-2 inhibitor for efficacy and adverse effects, and ensuring that the patient has a continuing need to keep taking the drug. Close attention also needs to be paid to intercurrent illnesses and new prescriptions that may reduce the safety of the COX-2 inhibitor. A standard NSAID plus a proton pump inhibitor may be equally effective as a COX-2 inhibitor in reducing the risk of gastroduodenal toxicity and if used the same prescribing advice applies. Current knowledge concerning the thrombotic potential of COX-2 inhibitors suggests that this combination, if tolerated, may be preferable to a COX-2 inhibitor, particularly where prolonged use is required. This knowledge also indicates that for patients with or at high risk of ischaemic heart disease or stroke, COX-2 inhibitors are

  7. Inhibitors of Histone Deacetylases Enhance Neurotoxicity of DNA Damage

    PubMed Central

    Vashishta, A.

    2014-01-01

    The nonselective inhibitors of class I/II histone deacetylases (HDACs) including trichostatin A and the clinically used suberoylanilide hydroxamic acid (SAHA, vorinostat) are neuroprotective in several models of neuronal injury. Here, we report that in cultured cortical neurons from newborn rats and in the cerebral cortex of whole neonate rats, these HDAC inhibitors exacerbated cytotoxicity of the DNA double-strand break (DSB)-inducing anticancer drug etoposide by enhancing apoptosis. Similar neurotoxic interactions were also observed in neurons that were treated with other DNA damaging drugs including cisplatin and camptothecin. In addition, in rat neonates, SAHA increased cortical neuron apoptosis that was induced by a single injection of the NMDA receptor antagonist dizocilpine (MK801). In etoposide-treated neurons, the nonselective HDAC inhibition resulted in more DSBs. It also potentiated etoposide-induced accumulation and phosphorylation of the pro-apoptotic transcription factor p53. Moreover, nonselective HDAC inhibition exacerbated neuronal apoptosis that was induced by the overexpressed p53. Importantly, such effects cannot be fully explained by inhibition of HDAC1, which is known to play a role in DSB repair and regulation of p53. The specific HDAC1 inhibitor MS275 only moderately enhanced etoposide-induced neuronal death. Although in etoposide-treated neurons MS275 increased DSBs, it did not affect activation of p53. Our findings suggest that besides HDAC1, there are other class I/II HDACs that participate in neuronal DNA damage response attenuating neurotoxic consequences of genotoxic insults to the developing brain. PMID:25063076

  8. [Angiotensin II receptor antagonists: different or equivalent?].

    PubMed

    Mounier-Vehier, C; Devos, P

    ARA-II: Angiotensin II receptor antagonists (ARA-II) belong to a recent class of antihypertensive drugs whose mechanism of action is similar to converting enzyme inhibitors (CEI). ARA-II are particularly interesting due to the excellent clinical and biological tolerance, similar to placebo, and their antihypertensive efficacy, comparable with classical drug classes. PUBLISHED TRIALS: A meta-analysis, published by Conlin in the American Journal of Hypertension, suggests that ARA-II, specifically losartan, valsartan, irbesartan and candesartan, have an equipotent blood pressure lowering effect. The careful lecture of this meta-analysis however discloses a faulty methodology from which no valid conclusion can be drawn. Since this early publication, several other comparative studies have been published. These multicentric, randomized double-blind studies enrolled a sufficient number of patients and demonstrated a clinical difference between certain ARA-II at usual dosages. CLINICAL PRACTICE: These studies do have an impact on everyday practice. For the practitioner, the goal is to obtain and then maintain a long-term and optimal reduction in the blood pressure level (reduction or prevention of target-organ disorders and cardiovascular complications of high blood pressure). This reduction in the cardiovascular risk will also depend directly on tolerance and compliance to the antihypertensive treatment. This element must also be considered in assessing treatment efficacy, independent of the blood pressure lowering effect. The results of several other studies will be published in 2001-2003. These large-scale studies on ARA-II related morbidity and mortality will be most useful in determining the role of these drugs in different therapeutic strategies compared with other drug classes.

  9. [Low-molecular cytolysins and trypsin inhibitors from sea anemone Radianthus macrodactylus. Isolation and partial characterization].

    PubMed

    Zykova, T A; Monastyrnaia, M M; Apalikova, O V; Shvets, T V; Kozlovskaia, E P

    1998-07-01

    Two low-molecular cytolytic toxins (RmI and RmII) and four trypsin inhibitors were isolated from the aqueous extract of sea anemone Radianthus macrodactylus. The method of isolation involved precipitation with acetone, gel filtration on acrylex P-4, ion-exchange chromatography on CM-32 cellulose, affinity chromatography on trypsin-binding sepharose 4B, ion exchange chromatography on an Ultrapore TSK CM-3SW column, and reversed phase HPLC on a Silasorb C18 column. RmI, RmII, and JnI inhibitor displayed molecular masses 5100, 6100, and 7100 Da, respectively, when subjected to SDS-PAGE. The isoelectric points were 9.2 and 9.3 for RmI and RmII, respectively. The amino acid composition and N-terminal amino acid residue (glycine) were determined for RmI, RmII, and JnI. Both proteins were nontoxic to mice and crabs. Hemolytic activity was determined to be 25 and 20 HU/mg for RmI and RmII, respectively, and their action on erythrocyte membrane was not inhibited by exogenous sphingomyelin. RmI and RmII exhibited antihistamine activity.

  10. Norepinephrine metabolism in neuronal cultures is increased by angiotensin II

    SciTech Connect

    Sumners, C.; Shalit, S.L.; Kalberg, C.J.; Raizada, M.K.

    1987-06-01

    In this study the authors have examined the actions of angiotensin II (ANG II) on catecholamine metabolism in neuronal brain cell cultures prepared from the hypothalamus and brain stem. Neuronal cultures prepared from the brains of 1-day-old Sprague-Dawley rats exhibit specific neuronal uptake mechanisms for both norepinephrine (NE) and dopamine (DA), and also monoamine oxidase (MAO) and catechol O-methyltransferase (COMT) activity. Separate neuronal uptake sites for NE and DA were identified by using specific neuronal uptake inhibitors for each amine. In previous studies, they determined that ANG II (10 nM-1 ..mu..M) stimulates increased neuronal (/sup 3/H)NE uptake by acting as specific receptors. They have confirmed these results here and in addition have shown that ANG II has not significant effects on neuronal (/sup 3/H)DA uptake. These results suggest that the actions of ANG II are restricted to the NE transporter in neuronal cultures. It is possible that ANG II stimulates the intraneuronal metabolism of at least part of the NE that is taken up, because the peptide stimulates MAO activity, an effect mediated by specific ANG II receptors. ANG II had no effect on COMT activity in neuronal cultures. Therefore, the use of neuronal cultures of hypothalamus and brain stem they have determined that ANG II can specifically alter NE metabolism in these areas, while apparently not altering DA metabolism.

  11. Simple preparation of aminothiourea-modified chitosan as corrosion inhibitor and heavy metal ion adsorbent.

    PubMed

    Li, Manlin; Xu, Juan; Li, Ronghua; Wang, Dongen; Li, Tianbao; Yuan, Maosen; Wang, Jinyi

    2014-03-01

    By a simple and convenient method of using formaldehyde as linkages, two new chitosan (CS) derivatives modified respectively with thiosemicarbazide (TSFCS) and thiocarbohydrazide (TCFCS) were synthesized. The new compounds were characterized and studied by Fourier transform infrared spectroscopy, elemental analysis, thermal gravity analysis and differential scanning calorimetry, and their surface morphologies were determined via scanning electron microscopy. These CS derivatives could form pH dependent gels. The behavior of 304 steel in 2% acetic acid containing different inhibitors or different concentrations of inhibitor had been studied by potentiodynamic polarization test. The preliminary results show that the new compound TCFCS can act as a mixed-type metal anticorrosion inhibitor in some extent; its inhibition efficiency is 92% when the concentration was 60 mg/L. The adsorption studies on a metal ion mixture aqueous solution show that two samples TSFCS and TCFCS can absorb As (V), Ni (II), Cu (II), Cd (II) and Pb (II) efficiently at pH 9 and 4.

  12. MMP Inhibitors on Dentin Stability

    PubMed Central

    Montagner, A.F.; Sarkis-Onofre, R.; Pereira-Cenci, T.; Cenci, M.S.

    2014-01-01

    The aim of this study was to systematically review the literature for in vitro and ex vivo studies that evaluated the effect of matrix metalloproteinase (MMP) inhibitors during the adhesive procedure on the immediate and long-term resin-dentin bond strength. The search was conducted in 6 databases with no publication year or language limits, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. From 1,336 potentially eligible studies, 48 were selected for full-text analysis, and 30 were included for review, with 17 considered in the meta-analysis. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. Pooled effect estimates were expressed as the weighted mean difference between groups. The most used MMP inhibitor was chlorhexidine (CHX). Immediate bond strength results showed no difference between 2% CHX and control; however, a difference was found between 0.2% CHX and control at baseline. After aging, CHX presented higher bond strength values compared to control groups (p < .05). However, this was not observed for longer periods of aging. High heterogeneity was found in some comparisons, especially for the water storage aging subgroup. Subgroup analyses showed that self-etching and etch-and-rinse adhesives are benefited by the CHX use. From the studies included, only 1 presented low risk of bias, while the others showed medium or high risk of bias. The use of MMP inhibitors did not affect the immediate bond strength overall, while it influenced the aged bond strength. Aging procedures influenced bond strength values of the dentin adhesion stability. PMID:24935066

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

    PubMed Central

    Ververis, Katherine; Hiong, Alison; Karagiannis, Tom C; Licciardi, Paul V

    2013-01-01

    Histone deacetylase (HDAC) inhibitors are an emerging class of therapeutics with potential as anticancer drugs. The rationale for developing HDAC inhibitors (and other chromatin-modifying agents) as anticancer therapies arose from the understanding that in addition to genetic mutations, epigenetic changes such as dysregulation of HDAC enzymes can alter phenotype and gene expression, disturb homeostasis, and contribute to neoplastic growth. The family of HDAC inhibitors is large and diverse. It includes a range of naturally occurring and synthetic compounds that differ in terms of structure, function, and specificity. HDAC inhibitors have multiple cell type-specific effects in vitro and in vivo, such as growth arrest, cell differentiation, and apoptosis in malignant cells. HDAC inhibitors have the potential to be used as monotherapies or in combination with other anticancer therapies. Currently, there are two HDAC inhibitors that have received approval from the US FDA for the treatment of cutaneous T-cell lymphoma: vorinostat (suberoylanilide hydroxamic acid, Zolinza) and depsipeptide (romidepsin, Istodax). More recently, depsipeptide has also gained FDA approval for the treatment of peripheral T-cell lymphoma. Many more clinical trials assessing the effects of various HDAC inhibitors on hematological and solid malignancies are currently being conducted. Despite the proven anticancer effects of particular HDAC inhibitors against certain cancers, many aspects of HDAC enzymes and HDAC inhibitors are still not fully understood. Increasing our understanding of the effects of HDAC inhibitors, their targets and mechanisms of action will be critical for the advancement of these drugs, especially to facilitate the rational design of HDAC inhibitors that are effective as antineoplastic agents. This review will discuss the use of HDAC inhibitors as multitargeted therapies for malignancy. Further, we outline the pharmacology and mechanisms of action of HDAC inhibitors while

  14. Novel bone-targeted Src tyrosine kinase inhibitor drug discovery.

    PubMed

    Shakespeare, William C; Metcalf, Chester A; Wang, Yihan; Sundaramoorthi, Raji; Keenan, Terence; Weigele, Manfred; Bohacek, Regine S; Dalgarno, David C; Sawyer, Tomi K

    2003-09-01

    Bone-targeted Src tyrosine kinase (STK) inhibitors have recently been developed for the treatment of osteoporosis and cancer-related bone diseases. The concept of bone targeting derives from bisphosphonates, and from the evolution of such molecules in terms of therapeutic efficacy for the treatment of bone disorders. Interestingly, some of the earliest bisphosphonates were recognized for their ability to inhibit calcium carbonate precipitation (scaling) by virtue of their affinity to chelate calcium. This chelating property was subsequently exploited in the development of bisphosphonate analogs as inhibitors of the bone-resorbing cells known as osteoclasts, giving rise to breakthrough medicines, such as Fosamax (for the treatment of osteoporosis) and Zometa (for the treatment of osteoporosis and bone metastases). Relative to these milestone achievements, there is a tremendous opportunity to explore beyond the limited chemical space (functional group diversity) of such bisphosphonates to design novel bone-targeting moieties, which may be used to develop other classes of promising small-molecule drugs affecting different biological pathways. Here, we review studies focused on bone-targeted inhibitors of STK, a key enzyme in osteoclast-dependent bone resorption. Two strategies are described relative to bone-targeted STK inhibitor drug discovery: (i) the development of novel Src homology (SH)-2 inhibitors incorporating non-hydrolyzable phosphotyrosine mimics and exhibiting molecular recognition and bone-targeting properties, leading to the in vivo-effective lead compound AP-22408; and (ii) the development of novel ATP-based Src kinase inhibitors incorporating bone-targeting moieties, leading to the in vivo-effective lead compound AP-23236. In summary, AP-22408 and AP-23236, which differ mechanistically by virtue of blocking Src-dependent non-catalytic or catalytic activities in osteoclasts, exemplify ARIAD Pharmaceuticals' structure-based design of novel bone

  15. Angiogenesis inhibitors in the treatment of lung cancer.

    PubMed

    Shepherd, F A

    2001-12-01

    Numerous inhibitors of angiogenesis are currently under study in lung cancer. Four trials of adjuvant interferon after chemotherapy for small cell lung cancer (SCLC) were negative. Several metalloproteinase inhibitors (MMPIs) are now in study in SCLC and non-small cell lung cancer (NSCLC). Two large randomized trials have closed recently in which Marimastat 10 mg bid was compared to placebo in responding patients with SCLC. Two randomized studies of Prinomastat versus placebo with combination chemotherapy in advanced NSCLC have also completed accrual. The results of these trials are not yet available, but should be reported in mid-2001. A Phase III trial of BMS-275291, a broad-spectrum MMPI in combination with paclitaxel and carboplatin is open for patients with advanced NSCLC. Neovastat, a standardized shark cartilage extract is under study in inoperable Stage III NSCLC. VEG-F gene expression is increased in many tumors including NSCLC, and may act as a paracrine mediator of growth. A randomized Phase II trial of paclitaxel and carboplatin with or without a recombinant humanized anti-VEG-F has been undertaken in NSCLC. Modestly better response and survival were seen with anti-VEG-F and a large Phase III trial is planned. Numerous receptor tyrosine kinases (TK) have been found to be directly or indirectly involved in angiogenesis including Flk-1, Flt-l, Tie-1 and Tie-2. SU5416 is a small molecular TK inhibitor and potent inhibitor of VEG-F-mediated Flk-1 receptor signaling. Another TK inhibitor SU6668 blocks VEG-F, bFGF and PDGF receptor signaling. It is orally available, and it may be evaluated in lung cancer trials in the near future. ZD4190 is an inhibitor of KDR/Flk-1 that may be evaluated in SCLC. Thalidomide has recently been shown in pre-clinical models to be anti-angiogenic. A randomized trial of paclitaxel/carboplatin and radiation with or without thalidomide is open for patients with Stage IIIB NSCLC in the United States. Numerous other anti

  16. 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

  17. Techniques for Screening Translation Inhibitors

    PubMed Central

    Osterman, Ilya A.; Bogdanov, Alexey A.; Dontsova, Olga A.; Sergiev, Petr V.

    2016-01-01

    The machinery of translation is one of the most common targets of antibiotics. The development and screening of new antibiotics usually proceeds by testing antimicrobial activity followed by laborious studies of the mechanism of action. High-throughput methods for new antibiotic screening based on antimicrobial activity have become routine; however, identification of molecular targets is usually a challenge. Therefore, it is highly beneficial to combine primary screening with the identification of the mechanism of action. In this review, we describe a collection of methods for screening translation inhibitors, with a special emphasis on methods which can be performed in a high-throughput manner. PMID:27348012

  18. Natural products as aromatase inhibitors.

    PubMed

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

    2008-08-01

    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 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.

  19. Do CDK4/6 inhibitors have potential as targeted therapeutics for squamous cell cancers?

    PubMed

    Kalu, Nene N; Johnson, Faye M

    2017-02-01

    Introduction Dysregulation of cell cycle progression has an established link to neoplasia and cancer progression. Components of the cyclin D-CDK4/6-INK4-Rb pathway are frequently altered in squamous cell carcinomas (SCCs) by diverse mechanisms, including viral oncogene-induced degradation, mutation, deletion, and amplification. Activation of the CDK4/6 pathway may predict response to CDK4/6 inhibitors and provide clinical biomarkers. Recently, the CDK4/6 inhibitor palbociclib showed clinical efficacy in combination with cetuximab in HNSCC patients. Areas covered This review focuses on the current research on the use of CDK4/6 inhibitors, comprising preclinical animal studies through phase II clinical trials across all SCCs. Expert opinion CDK4/6 inhibitors have a proven clinical benefit in breast cancer, but data on SCCs are sparse. Although frequent dysregulation of the cyclin D-CDK4/6-INK4-Rb pathway in SCCs suggests that targeting CDK4/6 may hold promise for improved clinical outcomes, single-agent activity has been modest in preclinical studies and absent in clinical studies. Combinations with immunotherapy or inhibitors of the PI3 K/mTOR or EGFR pathway may be effective. Given that SCCs caused by human papillomavirus have high levels of p16 and low levels of Rb, the CDK4/6 inhibitors are predicted to be ineffective in these cancers.

  20. Structure and inhibitor specificity of the PCTAIRE-family kinase CDK16

    PubMed Central

    Dixon-Clarke, Sarah E.; Shehata, Saifeldin N.; Krojer, Tobias; Sharpe, Timothy D.; vonDelft, Frank; Sakamoto, Kei

    2017-01-01

    CDK16 (also known as PCTAIRE1 or PCTK1) is an atypical member of the cyclin-dependent kinase (CDK) family that has emerged as a key regulator of neurite outgrowth, vesicle trafficking and cancer cell proliferation. CDK16 is activated through binding to cyclin Y via a phosphorylation-dependent 14-3-3 interaction and has a unique consensus substrate phosphorylation motif compared with conventional CDKs. To elucidate the structure and inhibitor-binding properties of this atypical CDK, we screened the CDK16 kinase domain against different inhibitor libraries and determined the co-structures of identified hits. We discovered that the ATP-binding pocket of CDK16 can accommodate both type I and type II kinase inhibitors. The most potent CDK16 inhibitors revealed by cell-free and cell-based assays were the multitargeted cancer drugs dabrafenib and rebastinib. An inactive DFG-out binding conformation was confirmed by the first crystal structures of CDK16 in separate complexes with the inhibitors indirubin E804 and rebastinib, respectively. The structures revealed considerable conformational plasticity, suggesting that the isolated CDK16 kinase domain was relatively unstable in the absence of a cyclin partner. The unusual structural features and chemical scaffolds identified here hold promise for the development of more selective CDK16 inhibitors and provide opportunity to better characterise the role of CDK16 and its related CDK family members in various physiological and pathological contexts. PMID:28057719

  1. Coevolutionary analysis of resistance-evading peptidomimetic inhibitors of HIV-1 protease.

    PubMed

    Rosin, C D; Belew, R K; Morris, G M; Olson, A J; Goodsell, D S

    1999-02-16

    We have developed a coevolutionary method for the computational design of HIV-1 protease inhibitors selected for their ability to retain efficacy in the face of protease mutation. For HIV-1 protease, typical drug design techniques are shown to be ineffective for the design of resistance-evading inhibitors: An inhibitor that is a direct analogue of one of the natural substrates will be susceptible to resistance mutation, as will inhibitors designed to fill the active site of the wild-type or a mutant enzyme. Two design principles are demonstrated: (i) For enzymes with broad substrate specificity, such as HIV-1 protease, resistance-evading inhibitors are best designed against the immutable properties of the active site-the properties that must be conserved in any mutant protease to retain the ability to bind and cleave all of the native substrates. (ii) Robust resistance-evading inhibitors can be designed by optimizing activity simultaneously against a large set of mutant enzymes, incorporating as much of the mutational space as possible.

  2. Coevolutionary analysis of resistance-evading peptidomimetic inhibitors of HIV-1 protease

    PubMed Central

    Rosin, Christopher D.; Belew, Richard K.; Morris, Garrett M.; Olson, Arthur J.; Goodsell, David S.

    1999-01-01

    We have developed a coevolutionary method for the computational design of HIV-1 protease inhibitors selected for their ability to retain efficacy in the face of protease mutation. For HIV-1 protease, typical drug design techniques are shown to be ineffective for the design of resistance-evading inhibitors: An inhibitor that is a direct analogue of one of the natural substrates will be susceptible to resistance mutation, as will inhibitors designed to fill the active site of the wild-type or a mutant enzyme. Two design principles are demonstrated: (i) For enzymes with broad substrate specificity, such as HIV-1 protease, resistance-evading inhibitors are best designed against the immutable properties of the active site—the properties that must be conserved in any mutant protease to retain the ability to bind and cleave all of the native substrates. (ii) Robust resistance-evading inhibitors can be designed by optimizing activity simultaneously against a large set of mutant enzymes, incorporating as much of the mutational space as possible. PMID:9990030

  3. Effects of camptothecin derivatives and topoisomerase dual inhibitors on Trypanosoma cruzi growth and ultrastructure

    PubMed Central

    2014-01-01

    Background Trypanosoma cruzi is the etiological agent of Chagas’ disease that is an endemic disease in Latin America and affects about 8 million people. This parasite belongs to the Trypanosomatidae family which contains a single mitochondrion with an enlarged region, named kinetoplast that harbors the mitochondrial DNA (kDNA). The kinetoplast and the nucleus present a great variety of essential enzymes involved in DNA replication and topology, including DNA topoisomerases. Such enzymes are considered to be promising molecular targets for cancer treatment and for antiparasitic chemotherapy. In this work, the proliferation and ultrastructure of T. cruzi epimastigotes were evaluated after treatment with eukaryotic topoisomerase I inhibitors, such as topotecan and irinotecan, as well as with dual inhibitors (compounds that block eukaryotic topoisomerase I and topoisomerase II activities), such as baicalein, luteolin and evodiamine. Previous studies have shown that such inhibitors were able to block the growth of tumor cells, however most of them have never been tested on trypanosomatids. Results Considering the effects of topoisomerase I inhibitors, our results showed that topotecan decreased cell proliferation and caused unpacking of nuclear heterochromatin, however none of these alterations were observed after treatment with irinotecan. The dual inhibitors baicalein and evodiamine decreased cell growth; however the nuclear and kinetoplast ultrastructures were not affected. Conclusions Taken together, our data showed that camptothecin is more efficient than its derivatives in decreasing T. cruzi proliferation. Furthermore, we conclude that drugs pertaining to a certain class of topoisomerase inhibitors may present different efficiencies as chemotherapeutical agents. PMID:24917086

  4. Suppression of microRNAs by dual-targeting and clustered Tough Decoy inhibitors

    PubMed Central

    Hollensen, Anne Kruse; Bak, Rasmus O.; Haslund, Didde; Mikkelsen, Jacob Giehm

    2013-01-01

    MicroRNAs (miRNAs) are ubiquitous regulators of gene expression that contribute to almost any cellular process. Methods for managing of miRNA activity are attracting increasing attention in relation to diverse experimental and therapeutic applications. DNA-encoded miRNA inhibitors expressed from plasmid or virus-based vectors provide persistent miRNA suppression and options of tissue-directed micromanaging. In this report, we explore the potential of exploiting short, hairpin-shaped RNAs for simultaneous suppression of two or more miRNAs. Based on the “Tough Decoy” (TuD) design, we create dual-targeting hairpins carrying two miRNA recognition sites and demonstrate potent co-suppression of different pairs of unrelated miRNAs by a single DNA-encoded inhibitor RNA. In addition, enhanced miRNA suppression is achieved by expression of RNA polymerase II-transcribed inhibitors carrying clustered TuD hairpins with up to a total of eight miRNA recognition sites. Notably, by expressing clustered TuD inhibitors harboring a single recognition site for each of a total of six miRNAs, we document robust parallel suppression of multiple miRNAs by inhibitor RNA molecules encoded by a single expression cassette. These findings unveil a new potential of TuD-based miRNA inhibitors and pave the way for standardizing synchronized suppression of families or clusters of miRNAs. PMID:23324610

  5. Structure and inhibitor specificity of the PCTAIRE-family kinase CDK16.

    PubMed

    Dixon-Clarke, Sarah E; Shehata, Saifeldin N; Krojer, Tobias; Sharpe, Timothy D; von Delft, Frank; Sakamoto, Kei; Bullock, Alex N

    2017-02-20

    CDK16 (also known as PCTAIRE1 or PCTK1) is an atypical member of the cyclin-dependent kinase (CDK) family that has emerged as a key regulator of neurite outgrowth, vesicle trafficking and cancer cell proliferation. CDK16 is activated through binding to cyclin Y via a phosphorylation-dependent 14-3-3 interaction and has a unique consensus substrate phosphorylation motif compared with conventional CDKs. To elucidate the structure and inhibitor-binding properties of this atypical CDK, we screened the CDK16 kinase domain against different inhibitor libraries and determined the co-structures of identified hits. We discovered that the ATP-binding pocket of CDK16 can accommodate both type I and type II kinase inhibitors. The most potent CDK16 inhibitors revealed by cell-free and cell-based assays were the multitargeted cancer drugs dabrafenib and rebastinib. An inactive DFG-out binding conformation was confirmed by the first crystal structures of CDK16 in separate complexes with the inhibitors indirubin E804 and rebastinib, respectively. The structures revealed considerable conformational plasticity, suggesting that the isolated CDK16 kinase domain was relatively unstable in the absence of a cyclin partner. The unusual structural features and chemical scaffolds identified here hold promise for the development of more selective CDK16 inhibitors and provide opportunity to better characterise the role of CDK16 and its related CDK family members in various physiological and pathological contexts.

  6. Angiotensin II Enhances Connecting Tubule Glomerular Feedback (CTGF)

    PubMed Central

    Ren, YiLin; D’Ambrosio, Martin A.; Garvin, Jeffrey L.; Carretero, Oscar A.

    2011-01-01

    Increasing Na delivery to epithelial Na channels (ENaC) in the connecting tubule (CNT) causes dilation of the afferent arteriole (Af-Art), a process we call CNT glomerular feedback (CTGF). Angiotensin II (Ang II) stimulates ENaC in the collecting duct via AT1 receptors. We hypothesized that Ang II in the CNT lumen enhances CTGF by activation of AT1 receptors, protein kinase C (PKC) and ENaC. Rabbit Af-Arts and their adherent CNT were microperfused and preconstricted with norepinephrine. Each experiment involved generating two consecutive concentration-response curves by increasing NaCl in the CNT lumen. During the control period, the maximum dilation of the Af-Art was 7.9 ± 0.4 μm, and the concentration of NaCl in the CNT needed to achieve half maximal response (EC50) was 34.7 ± 5.2 mmol/L. After adding Ang II (10−9 mol/L) to the CNT lumen, the maximal response was 9.5 ± 0.7 μm and the EC50 was 11.6 ± 1.3 mmol/L (P=0.01 vs. control). Losartan, an AT1 antagonist (10−6 mol/L) blocked the stimulatory effect of Ang II, PD123319, an AT2 antagonist (10−6 mol/L) did not. The PKC inhibitor staurosporine (10−8 mol/L) added to the CNT inhibited the stimulatory effect of Ang II. The ENaC inhibitor benzamil (10−6 mol/L) prevented both CTGF and its stimulation by Ang II. We concluded that Ang II in the CNT lumen enhances CTGF via activation of AT1, and that this effect requires activation of PKC and ENaC. Potentiation of CTGF by Ang II could help preserve glomerular filtration rate in the presence of renal vasoconstriction. PMID:20696981

  7. C1 inhibitor: quantification and purification.

    PubMed

    Varga, Lilian; Dobó, József

    2014-01-01

    C1 inhibitor is a multipotent serpin capable of inhibiting the classical and the lectin pathways of complement, the fibrinolytic system, and contact/kinin system of coagulation. Deficiency of C1 inhibitor manifest as hereditary angioedema (HAE), an autosomal dominant hereditary disease. Measuring the C1 inhibitor level is of vital importance for the diagnosis of HAE and also for monitoring patients receiving C1 inhibitor for therapy. Determination of the antigenic C1 inhibitor level by the radial immunodiffusion (RID) technique is described in detail in this chapter. The presented purification method of plasma C1 inhibitor is primarily based on its high carbohydrate content and its affinity to the lectin jacalin.

  8. Tubulin inhibitors: a patent survey.

    PubMed

    Nepali, Kunal; Ojha, Ritu; Sharma, Sahil; Bedi, Preet M S; Dhar, Kanaya L

    2014-05-01

    Tubulin is one of the most useful and strategic molecular targets for anticancer drugs. The dynamic process of microtubule assembly and disassembly can be blocked by various agents that bind to distinct sites in the β-tubulin subunit. By interfering with microtubule function in vitro, these agents arrest cells in mitosis, eventually leading to cell death, by both apoptosis and necrosis. So far, three binding domains have been identified a) the colchicine site close to the α/β interface, b) the area where the vinca alkaloids bind, and c) the taxane-binding pocket. This review compiles the patent literature up to 2013 and offers a detailed account of all the advances on Tubulin inhibitors (lead molecules) along with in depth knowledge about the number of novel scaffolds, modified analogs and derivatives of the lead molecules. Colchicine binding site remains the most explored site indicated by the patent survey as majority of the patents revolves around phenstatin and combretastatin based molecules where the key structural feature for tubulin inhibition is an appropriate arrangement of the two aromatic rings at an appropriate distance and optimal dihedral angle maximizing interactions with tubulin. A brief account of promising tubulin inhibitors in stages of clinical development and some strategies for the development of potent molecules overcoming the problem of drug resistance have also been discussed.

  9. Aromatase inhibitors and bone loss.

    PubMed

    Perez, Edith A; Weilbaecher, Katherine

    2006-08-01

    The aromatase inhibitors (AIs) anastrozole (Arimidex), letrozole (Femara), and exemestane (Aromasin) are significantly more effective than the selective estrogen-receptor modulator (SERM) tamoxifen in preventing recurrence in estrogen receptor-positive early breast cancer. Aromatase inhibitors are likely to replace SERMs as first-line adjuvant therapy for many patients. However, AIs are associated with significantly more osteoporotic fractures and greater bone mineral loss. As antiresorptive agents, oral and intravenous bisphosphonates such as alendronate (Fosamax), risedronate (Actonel), ibandronate (Boniva), pamidronate (Aredia), and zoledronic acid (Zometa) have efficacy in preventing postmenopausal osteoporosis, cancer treatment-related bone loss, or skeletal complications of metastatic disease. Clinical practice guidelines recommend baseline and annual follow-up bone density monitoring for all patients initiating AI therapy. Bisphosphonate therapy should be prescribed for patients with osteoporosis (T score < -2.5) and considered on an individual basis for those with osteopenia (T score < -1). Modifiable lifestyle behaviors including adequate calcium and vitamin D intake, weight-bearing exercise, and smoking cessation should be addressed. Adverse events associated with bisphosphonates include gastrointestinal toxicity, renal toxicity, and osteonecrosis of the jaw. These safety concerns should be balanced with the potential of bisphosphonates to minimize or prevent the debilitating effects of AI-associated bone loss in patients with early, hormone receptor-positive breast cancer.

  10. α-glucosidase inhibitors from Brickellia cavanillesii.

    PubMed

    Escandón-Rivera, Sonia; González-Andrade, Martin; Bye, Robert; Linares, Edelmira; Navarrete, Andrés; Mata, Rachel

    2012-05-25

    An aqueous extract from the aerial parts of Brickellia cavanillesii attenuated postprandial hyperglycemia in diabetic mice during oral glucose and sucrose tolerance tests. Experimental type-II DM was achieved by treating mice with streptozotocin (100 mg/kg) and β-nicotinamide adenine dinucleotide (40 mg/kg). These pharmacological results demonstrated that B. cavanillesii is effective for controlling fasting and postprandial blood glucose levels in animal models. The same aqueous extract also showed potent inhibitory activity (IC(50) = 0.169 vs 1.12 mg/mL for acarbose) against yeast α-glucosidase. Bioassay-guided fractionation of the active extract using the α-glucosidase inhibitory assay led to the isolation of several compounds including two chromenes [6-acetyl-5-hydroxy-2,2-dimethyl-2H-chromene (1) and 6-hydroxyacetyl-5-hydroxy-2,2-dimethyl-2H-chromene (2)], two sesquiterpene lactones [caleins B (3) and C (4)], several flavonoids [acacetin (5), genkwanin (6), isorhamnetin (7), kaempferol (8), and quercetin (9)], and 3,5-di-O-caffeoylquinic acid (10). Chromene 2 is a new chemical entity. Compounds 2, 4, 7, and 9 inhibited the activity of yeast α-glucosidase with IC(50) 0.42, 0.28, 0.16, and 0.53 mM, respectively, vs 1.7 mM for acarbose. Kinetic analysis revealed that compounds 4 and 7 behaved as mixed-type inhibitors with K(i) values of 1.91 and 0.41 mM, respectively, while 2 was noncompetititive, with a K(i) of 0.13 mM. Docking analysis predicted that these compounds, except 2, bind to the enzyme at the catalytic site.

  11. Heterotrimetallic Ru(II)/Pd(II)/Ru(II) complexes: synthesis, crystalstructure, spectral characterization, DFT calculation and antimicrobial study.

    PubMed

    Al-Noaimi, Mousa; Nafady, Ayman; Warad, Ismail; Alshwafy, Rwaida; Husein, Ahmad; Talib, Wamidh H; Hadda, Taibi Ben

    2014-03-25

    New ruthenium(II) mononuclear complexes of the type [RuCl2(PPh3)2(η(2)-triamine)] (2) [RuCl(PPh3)2(η(3)-triamine)]Cl (5) (triemine=N(1)-(2-aminoethyl)-1,2-ethanediamine) have been synthesized by reacting [RuCl2(PPh3)3] (1) with one mole equivalent of N(1)-(2-aminoethyl)-1,2-ethanediamine in dichloromethane. Reaction of (2) with half-equivalent of (PhCN)2PdCl2 or Pd(OAc)2 in dichloromethane as a solvent afforded two novel heterotrimetallic Ru(II)-Pd(II)-Ru(II) complexes, [Ru(II)Cl2(PPh3)2(triamine)]2[Pd(II)X2](X=Cl, OAc) (3 and 4), bearing bioactive ligand. The progress of the undertaken reactions was monitored by (31)P{1H} NMR and FTIR. Crystal structure of complex 2 was confirmed by X-ray diffraction. The absorption spectrum of 2 in dichloromethane was modeled by time-dependent density functional theory (TD-DFT). The in vitro antimicrobial studies of complex 2-5 against an array of microorganisms (bacteria and fungi) were conducted. Complexes 3 and 4 exhibit high dual antibacterial and antifungal activity inhibiting microorganisms possibly via hydrolytic pathway which further evidenced by electrochemical analyses. The complexes 3 and 4 show a high inhibitory activity at 200 μg/ml concentration, suggesting that complexes 3 and 4 are two efficient catalytic inhibitor of microorganisms and further, they should be tested against cancer strains.

  12. Plant Biofilm Inhibitors to Discover Biofilm Genes

    DTIC Science & Technology

    2011-04-08

    REPORT Final Report for Plant Biofilm Inhibitors to Discover Biofilm Genes 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: To control biofilms , we have...synthesized the natural biofilm inhibitor (5Z)-4-bromo-5-(bromomethylene) -3-butyl-2(5H)-furanone from the red alga Delisea pulchra and determined that...Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS biofilms , biofilm inhibitors Thomas K. Wood Texas Engineering

  13. Angiotensin II Blockade and Renal Protection

    PubMed Central

    Kobori, Hiroyuki; Mori, Hirohito; Masaki, Tsutomu; Nishiyama, Akira

    2013-01-01

    Current national guidelines have recommended the use of renin-angiotensin system inhibitors, including angiotensin II type 1 receptor blockers (ARBs), in preference to other antihypertensive agents for treating hypertensive patients with chronic kidney disease. However, the mechanisms underlying the renoprotective effects of ARBs are multiple and complex. Blood pressure reduction by systemic vasodilation with an ARB contributes to its beneficial effects in treating kidney disease. Furthermore, ARB-induced renal vasodilation results in an increase in renal blood flow, leading to improvement of renal ischemia and hypoxia. ARBs are also effective in reducing urinary albumin excretion through a reduction in intraglomerular pressure and the protection of glomerular endothelium and/or podocyte injuries. In addition to blocking angiotensin II-induced renal cell and tissue injuries, ARBs can decrease intrarenal angiotensin II levels by reducing proximal tubular angiotensinogen and production of collecting duct renin, as well as angiotensin II accumulation in the kidney. In this review, we will briefly summarize our current understanding of the pharmacological effects of an ARB in the kidney. We will also discuss the possible mechanisms responsible for the renoprotective effects of ARBs on type 2 diabetic nephropathy. PMID:23176216

  14. [Development of new antiatherosclerotic agents--ACAT inhibitors and CETP inhibitors].

    PubMed

    Miyazaki, A; Horiuchi, S

    1999-12-01

    Development of new antiatherosclerotic agents were reviewed focusing on ACAT inhibitors and CETP inhibitors. ACAT inhibitors enhance intracellular degradation of VLDL in hepatocytes. Cholesterol absorption in small intestine is inhibited by ACAT inhibitors. Thus, ACAT inhibitors reduce plasma cholesterol levels. In atherosclerotic lesions, ACAT inhibitors suppress foam cell formation (cholesteryl ester accumulation) in macrophages. Since ACAT inhibitors have multiple anti-atherogenic effects, they are considered future drugs controlling hypercholesterolemia and atherosclerosis. CETP inhibitors are expected to increase HDL and decrease LDL. Although the patients with CETP deficiency show high level of HDL, recent studies showed that they are not necessarily resistant to atherosclerosis. The strategy to inhibit CETP for suppressing atherosclerosis has not been established.

  15. An Integrated Model of RAF Inhibitor Action Predicts Inhibitor Activity against Oncogenic BRAF Signaling.

    PubMed

    Karoulia, Zoi; Wu, Yang; Ahmed, Tamer A; Xin, Qisheng; Bollard, Julien; Krepler, Clemens; Wu, Xuewei; Zhang, Chao; Bollag, Gideon; Herlyn, Meenhard; Fagin, James A; Lujambio, Amaia; Gavathiotis, Evripidis; Poulikakos, Poulikos I

    2016-09-12

    The complex biochemical effects of RAF inhibitors account for both the effectiveness and mechanisms of resistance to these drugs, but a unified mechanistic model has been lacking. Here we show that RAF inhibitors exert their effects via two distinct allosteric mechanisms. Drug resistance due to dimerization is determined by the position of the αC helix stabilized by inhibitor, whereas inhibitor-induced RAF priming and dimerization are the result of inhibitor-induced formation of the RAF/RAS-GTP complex. The biochemical effect of RAF inhibitor in cells is the combined outcome of the two mechanisms. Therapeutic strategies including αC-helix-IN inhibitors are more effective in multiple mutant BRAF-driven tumor models, including colorectal and thyroid BRAF(V600E) cancers, in which first-generation RAF inhibitors have been ineffective.

  16. Overlapping and Divergent Actions of Structurally Distinct Histone Deacetylase Inhibitors in Cardiac Fibroblasts.

    PubMed

    Schuetze, Katherine B; Stratton, Matthew S; Blakeslee, Weston W; Wempe, Michael F; Wagner, Florence F; Holson, Edward B; Kuo, Yin-Ming; Andrews, Andrew J; Gilbert, Tonya M; Hooker, Jacob M; McKinsey, Timothy A

    2017-04-01

    Inhibitors of zinc-dependent histone deacetylases (HDACs) profoundly affect cellular function by altering gene expression via changes in nucleosomal histone tail acetylation. Historically, investigators have employed pan-HDAC inhibitors, such as the hydroxamate trichostatin A (TSA), which simultaneously targets members of each of the three zinc-dependent HDAC classes (classes I, II, and IV). More recently, class- and isoform-selective HDAC inhibitors have been developed, providing invaluable chemical biology probes for dissecting the roles of distinct HDACs in the control of various physiologic and pathophysiological processes. For example, the benzamide class I HDAC-selective inhibitor, MGCD0103 [N-(2-aminophenyl)-4-[[(4-pyridin-3-ylpyrimidin-2-yl)amino]methyl] benzamide], was shown to block cardiac fibrosis, a process involving excess extracellular matrix deposition, which often results in heart dysfunction. Here, we compare the mechanisms of action of structurally distinct HDAC inhibitors in isolated primary cardiac fibroblasts, which are the major extracellular matrix-producing cells of the heart. TSA, MGCD0103, and the cyclic peptide class I HDAC inhibitor, apicidin, exhibited a common ability to enhance histone acetylation, and all potently blocked cardiac fibroblast cell cycle progression. In contrast, MGCD0103, but not TSA or apicidin, paradoxically increased expression of a subset of fibrosis-associated genes. Using the cellular thermal shift assay, we provide evidence that the divergent effects of HDAC inhibitors on cardiac fibroblast gene expression relate to differential engagement of HDAC1- and HDAC2-containing complexes. These findings illustrate the importance of employing multiple compounds when pharmacologically assessing HDAC function in a cellular context and during HDAC inhibitor drug development.

  17. Anti-tumor efficacy study of the Bruton's tyrosine kinase (BTK) inhibitor, ONO/GS-4059, in combination with the glycoengineered type II anti-CD20 monoclonal antibody obinutuzumab (GA101) demonstrates superior in vivo efficacy compared to ONO/GS-4059 in combination with rituximab.

    PubMed

    Yasuhiro, Tomoko; Sawada, Wako; Klein, Christian; Kozaki, Ryohei; Hotta, Shingo; Yoshizawa, Toshio

    2017-03-01

    The activated B-cell diffuse large B-cell-like lymphoma (ABC-DLBCL) correlates with poor prognosis. The B-cell receptor signaling pathway is known to be dysregulated in NHL/CLL and given BTK is a downstream mediator of BCR signaling, BTK constitutes an interesting and obvious therapeutic target. Given the high potency and selectivity of the BTK inhibitor, ONO/GS-4059, it was hypothesized that, the anti-tumor activity of ONO/GS-4059 could be further enhanced by combining it with the anti-CD20 Abs, rituximab (RTX) or obinutuzumab (GA101). ONO/GS-4059 combined with GA101 or RTX was significantly better than the respective monotherapy with tumor growth inhibition (TGI) of 90% for the GA101 combination and 86% for the RTX combination. In contrast, ibrutinib (PCI-32765) combined with RTX did not result in improved efficacy compared with respective monotherapy. Taken together these data indicate that the combination of ONO/GS-4059 with rituximab and particularly obinutuzumab may be an effective treatment for ABC-DLBCL.

  18. Trypsin inhibitors from the garden four o'clock (Mirabilis jalapa) and spinach (Spinacia oleracea) seeds: isolation, characterization and chemical synthesis.

    PubMed

    Kowalska, Jolanta; Pszczoła, Katarzyna; Wilimowska-Pelc, Anna; Lorenc-Kubis, Irena; Zuziak, Ewa; Ługowski, Mateusz; Łegowska, Anna; Kwiatkowska, Anna; Sleszyńska, Małgorzata; Lesner, Adam; Walewska, Aleksandra; Zabłotna, Ewa; Rolka, Krzysztof; Wilusz, Tadeusz

    2007-06-01

    Five serine proteinase inhibitors (Mirabilis jalapa trypsin inhibitors, MJTI I and II and Spinacia oleracea trypsin inhibitors, SOTI I, II, and III) from the garden four-o'clock (M. jalapa) and spinach (S. oleracea) seeds were isolated. The purification procedures included affinity chromatography on immobilized methylchymotrypsin in the presence of 5M NaCl, ion exchange chromatography and/or preparative electrophoresis, and finally RP-HPLC on a C-18 column. The inhibitors, crosslinked by three disulfide bridges, are built of 35 to 37 amino-acid residues. Their primary structures differ from those of known trypsin inhibitors, but showed significant similarity to the antimicrobial peptides isolated from the seeds of M. jalapa (MJ-AMP1, MJ-AMP2), Mesembryanthemum crystallinum (AMP1), and Phytolacca americana (AMP-2 and PAFP-S) and from the hemolymph of Acrocinus longimanus (Alo-1, 2 and 3). The association equilibrium constants (K(a)) with bovine beta-trypsin for the inhibitors from M. jalapa (MJTI I and II) and S. oleracea (SOTI I-III) were found to be about 10(7)M(-1). Fully active MJTI I and SOTI I were obtained by solid-phase peptide synthesis. The disulfide bridge pattern in both inhibitors (Cys1-Cys4, Cys2-Cys5 and Cys3-Cys6) was established after their digestion with thermolysin and proteinase K followed by the MALDI-TOF analysis.

  19. Discovery of Potent Carbonic Anhydrase and Acetylcholinesterase Inhibitors: 2-Aminoindan β-Lactam Derivatives

    PubMed Central

    Genç, Hayriye; Kalin, Ramazan; Köksal, Zeynep; Sadeghian, Nastaran; Kocyigit, Umit M.; Zengin, Mustafa; Gülçin, İlhami; Özdemir, Hasan

    2016-01-01

    β-Lactams are pharmacologically important compounds because of their various biological uses, including antibiotic and so on. β-Lactams were synthesized from benzylidene-inden derivatives and acetoxyacetyl chloride. The inhibitory effect of these compounds was examined for human carbonic anhydrase I and II (hCA I, and II) and acetylcholinesterase (AChE). The results reveal that β-lactams are inhibitors of hCA I, II and AChE. The Ki values of β-lactams (2a–k) were 0.44–6.29 nM against hCA I, 0.93–8.34 nM against hCA II, and 0.25–1.13 nM against AChE. Our findings indicate that β-lactams (2a–k) inhibit both carbonic anhydrases (CA) isoenzymes and AChE at low nanomolar concentrations. PMID:27775608

  20. Angiotensin II induces the expression of c-reactive protein via MAPK-dependent signal pathway in U937 macrophages.

    PubMed

    Li, Ming; Liu, Juntian; Han, Chunjie; Wang, Bin; Pang, Xiaoming; Mao, Junjun

    2011-01-01

    Atherosclerosis is an inflammatory disease in the vessel wall. As an inflammatory molecule, C-reactive protein (CRP) participates in all stages of atherosclerotic process. Although angiotensin II (Ang II) can stimulate the vascular cells to produce CRP, it is unknown whether Ang II induces CRP expression in macrophages. The present study was to observe effect of Ang II on CRP production and the related signal pathway in U937 macrophages so as to provide more evidence for the proinflammatory action of Ang II. The results showed that Ang II significantly increased mRNA and protein expression of CRP in U937 macrophages in time- and concentration-dependent manners. AT(1) receptor blocker losartan blocked Ang II -induced CRP expression in mRNA and protein levels in U937 macrophages. Losartan and complex II inhibitor TIFA decreased Ang II -stimulated reactive oxygen species (ROS) generation, and antioxidant NAC completely abolished Ang II -induced CRP expression in U937 macrophages. The further study indicated that losartan, NAC, MEK1/2 inhibitor PD98059, p38MAPK inhibitor SB203580 obviously inhibited ERK1/2 and p38MAPK phosphorylation, and PD98059, SB203580 and NF-κB inhibitor PDTC reduced Ang II -induced mRNA and protein expression of CRP in U937 macrophages. These demonstrate that Ang II is capable of inducing CRP generation in macrophages via AT(1)-ROS-ERK1/2/p38MAPK-NF-κB signal pathway, which contributes to better understanding of the proinflammatory and proatherosclerotic actions of Ang II.

  1. Angiotensin II Increased Neuronal Stem Cell Proliferation: Role of AT2R

    PubMed Central

    Chao, Jie; Yang, Lu; Buch, Shilpa; Gao, Lie

    2013-01-01

    Angiotensin II (Ang II), known a potent vasoactive substance in the renin-angiotensin system in the brain, plays a critical role in systemic blood pressure control. However, increasing evidence indicated that the physiological role of Ang II go beyond its vasoactive effect. In the present study, we demonstrated that Ang II type-1 receptor (AT1R) and type-2 receptor (AT2R) were expressed in primary rat hippocampal neuronal stem cells (NSCs). Treatment of rat hippocampal NSCs with Ang II increased cell proliferation. Pretreatment of NSCs with specific AT2R, but not AT1R, antagonist significantly suppressed Ang II-induced cell proliferation. Furthermore, Ang II stimulated ERK and Akt phosphorylation in NSCs. Pretreatment of MEK inhibitor, but not PI3K inhibitor, inhibited Ang II-induced ERK phosphorylation as well as cell proliferation. In addition, stimulation of NSCs with Ang II decreased expression of KV 1.2/KV 3.1 channels and blocked K+ currents which lie downstream of ERK activation. Taken together, these findings underpin the role of AT2R as a novel target that regulates cell proliferation mediated by Ang II with implications for therapeutic intervention for regulation of neurogenesis. PMID:23691054

  2. The lantibiotic mersacidin inhibits peptidoglycan synthesis by targeting lipid II.

    PubMed

    Brötz, H; Bierbaum, G; Leopold, K; Reynolds, P E; Sahl, H G

    1998-01-01

    The lantibiotic mersacidin exerts its bactericidal action by inhibition of peptidoglycan biosynthesis. It interferes with the membrane-associated transglycosylation reaction; during this step the ultimate monomeric peptidoglycan precursor, undecaprenyl-pyrophosphoryl-MurNAc-(pentapeptide)-GlcNAc (lipid II) is converted into polymeric nascent peptidoglycan. In the present study we demonstrate that the molecular basis of this inhibition is the interaction of mersacidin with lipid II. The adsorption of [14C]mersacidin to growing cells, as well as to isolated membranes capable of in vitro peptidoglycan synthesis, was strictly dependent on the availability of lipid II, and antibiotic inhibitors of lipid II formation strongly interfered with this binding. Direct evidence for the interaction was provided by studies with isolated lipid II. [14C]mersacidin associated tightly with [14C]lipid II micelles; the complex was stable even in the presence of 1% sodium dodecyl sulfate. Furthermore, the addition of isolated lipid II to the culture broth efficiently antagonized the bactericidal activity of mersacidin. In contrast to the glycopeptide antibiotics, complex formation does not involve the C-terminal D-alanyl-D-alanine moiety of the lipid intermediate. Thus, the interaction of mersacidin with lipid II apparently occurs via a binding site which is not targeted by any antibiotic currently in use.

  3. Control of glomerular filtration rate by circulating angiotensin II.

    PubMed

    Hall, J E; Coleman, T G; Guyton, A C; Kastner, P R; Granger, J P

    1981-09-01

    Previous studies from our laboratory have provided evidence that the renin-angiotensin system plays an important role in controlling glomerular filtration rate (GFR) through an efferent arteriolar vasoconstrictor mechanism; however, the relative importance of circulating versus intrarenally formed angiotensin II (ANG II) in this control has not been determined. In the present study, the role of circulating ANG II in regulating GFR during reduced renal artery pressure (RAP) was examined in sodium-depleted dogs. After 90 min of infusion of the angiotensin-converting enzyme inhibitor SQ 14225, which presumably inhibited formation of both circulating and intrarenal ANG II, reduction of RAP to 81 +/- 2 mmHg resulted in marked decreases in GFR, filtration fraction (FF), and calculated efferent arteriolar resistance (RE), whereas renal blood flow (RBF) was maintained approximately 40% above initial control levels determined before SQ 14225 infusion. Replacement of circulating ANG II during SQ 14225 infusion, by intravenous infusion of ANG II at rates that decreased RBF to control levels, increased GFR, FF, and RE to levels not significantly different from control while RAP was maintained constant by aortic constriction. These observations suggest that circulating ANG II plays an important role in regulating RE and GFR during reductions in RAP. The importance of intrarenally formed ANG II in controlling GFR remains to be determined.

  4. Novel inhibitors of the calcineurin/NFATc hub - alternatives to CsA and FK506?

    PubMed Central

    Sieber, Matthias; Baumgrass, Ria

    2009-01-01

    The drugs cyclosporine A (CsA) and tacrolimus (FK506) revolutionized organ transplantation. Both compounds are still widely used in the clinic as well as for basic research, even though they have dramatic side effects and modulate other pathways than calcineurin-NFATc, too. To answer the major open question - whether the adverse side effects are secondary to the actions of the drugs on the calcineurin-NFATc pathway - alternative inhibitors were developed. Ideal inhibitors should discriminate between the inhibition of (i) calcineurin and peptidyl-prolyl cis-trans isomerases (PPIases; the matchmaker proteins of CsA and FK506), (ii) calcineurin and the other Ser/Thr protein phosphatases, and (iii) NFATc and other transcription factors. In this review we summarize the current knowledge about novel inhibitors, synthesized or identified in the last decades, and focus on their mode of action, specificity, and biological effects. PMID:19860902

  5. Angiotensin-I-Converting Enzyme (ACE) Inhibitors from Marine Resources: Prospects in the Pharmaceutical Industry

    PubMed Central

    Wijesekara, Isuru; Kim, Se-Kwon

    2010-01-01

    Hypertension or high blood pressure is one of the major independent risk factors for cardiovascular diseases. Angiotensin-I-converting enzyme (EC 3.4.15.1; ACE) plays an important physiological role in regulation of blood pressure by converting angiotensin I to angiotensin II, a potent vasoconstrictor. Therefore, the inhibition of ACE activity is a major target in the prevention of hypertension. Recently, the search for natural ACE inhibitors as alternatives to synthetic drugs is of great interest to prevent several side effects and a number of novel compounds such as bioactive peptides, chitooligosaccharide derivatives (COS) and phlorotannins have been derived from marine organisms as potential ACE inhibitors. These inhibitory derivatives can be developed as nutraceuticals and pharmaceuticals with potential to prevent hypertension. Hence, the aim of this review is to discuss the marine-derived ACE inhibitors and their future prospects as novel therapeutic drug candidates for treat hypertension. PMID:20479968

  6. RVX-208, an inhibitor of BET transcriptional regulators with selectivity for the second bromodomain

    PubMed Central

    Picaud, Sarah; Wells, Christopher; Felletar, Ildiko; Brotherton, Deborah; Martin, Sarah; Savitsky, Pavel; Diez-Dacal, Beatriz; Philpott, Martin; Bountra, Chas; Lingard, Hannah; Fedorov, Oleg; Müller, Susanne; Brennan, Paul E.; Knapp, Stefan; Filippakopoulos, Panagis

    2013-01-01

    Bromodomains have emerged as attractive candidates for the development of inhibitors targeting gene transcription. Inhibitors of the bromo and extraterminal (BET) family recently showed promising activity in diverse disease models. However, the pleiotropic nature of BET proteins regulating tissue-specific transcription has raised safety concerns and suggested that attempts should be made for domain-specific targeting. Here, we report that RVX-208, a compound currently in phase II clinical trials, is a BET bromodomain inhibitor specific for second bromodomains (BD2s). Cocrystal structures revealed binding modes of RVX-208 and its synthetic precursor, and fluorescent recovery after photobleaching demonstrated that RVX-208 displaces BET proteins from chromatin. However, gene-expression data showed that BD2 inhibition only modestly affects BET-dependent gene transcription. Our data demonstrate the feasibility of specific targeting within the BET family resulting in different transcriptional outcomes and highlight the importance of BD1 in transcriptional regulation. PMID:24248379

  7. RVX-208, an inhibitor of BET transcriptional regulators with selectivity for the second bromodomain.

    PubMed

    Picaud, Sarah; Wells, Christopher; Felletar, Ildiko; Brotherton, Deborah; Martin, Sarah; Savitsky, Pavel; Diez-Dacal, Beatriz; Philpott, Martin; Bountra, Chas; Lingard, Hannah; Fedorov, Oleg; Müller, Susanne; Brennan, Paul E; Knapp, Stefan; Filippakopoulos, Panagis

    2013-12-03

    Bromodomains have emerged as attractive candidates for the development of inhibitors targeting gene transcription. Inhibitors of the bromo and extraterminal (BET) family recently showed promising activity in diverse disease models. However, the pleiotropic nature of BET proteins regulating tissue-specific transcription has raised safety concerns and suggested that attempts should be made for domain-specific targeting. Here, we report that RVX-208, a compound currently in phase II clinical trials, is a BET bromodomain inhibitor specific for second bromodomains (BD2s). Cocrystal structures revealed binding modes of RVX-208 and its synthetic precursor, and fluorescent recovery after photobleaching demonstrated that RVX-208 displaces BET proteins from chromatin. However, gene-expression data showed that BD2 inhibition only modestly affects BET-dependent gene transcription. Our data demonstrate the feasibility of specific targeting within the BET family resulting in different transcriptional outcomes and highlight the importance of BD1 in transcriptional regulation.

  8. Geranyl and Neryl Triazole Bisphosphonates as Inhibitors of Geranylgeranyl Diphosphate Synthase

    PubMed Central

    Zhou, Xiang; Ferree, Sarah D.; Wills, Veronica S.; Born, Ella J.; Tong, Huaxiang; Holstein, Sarah A.

    2014-01-01

    When inhibitors of enzymes that utilize isoprenoid pyrophosphates are based on the natural substrates, a significant challenge can be to achieve selective inhibition of a specific enzyme. One element in the design process is the stereochemistry of the isoprenoid olefins. We recently reported preparation of a series of isoprenoid triazoles as potential inhibitors of geranylgeranyl transferase II but these compounds were obtained as a mixture of olefin isomers. We now have accomplished the stereoselective synthesis of these triazoles through the use of epoxy azides for the cycloaddition reaction followed by regeneration of the desired olefin. Both geranyl and neryl derivatives have been prepared as single olefin isomers through parallel reaction sequences. The products were assayed against multiple enzymes as well as in cell culture studies and surprisingly a Z-olefin isomer was found to be a potent and selective inhibitor of geranylgeranyl diphosphate synthase. PMID:24726306

  9. Synthesis of quaternary α-amino acid-based arginase inhibitors via the Ugi reaction.

    PubMed

    Golebiowski, Adam; Whitehouse, Darren; Beckett, R Paul; Van Zandt, Michael; Ji, Min Koo; Ryder, Todd R; Jagdmann, Erik; Andreoli, Monica; Lee, Yung; Sheeler, Ryan; Conway, Bruce; Olczak, Jacek; Mazur, Marzena; Czestkowski, Wojciech; Piotrowska, Wieslawa; Cousido-Siah, Alexandra; Ruiz, Francesc X; Mitschler, Andre; Podjarny, Alberto; Schroeter, Hagen

    2013-09-01

    The Ugi reaction has been successfully applied to the synthesis of novel arginase inhibitors. In an effort to decrease conformational flexibility of the previously reported series of 2-amino-6-boronohexanoic acid (ABH) analogs 1, we designed and synthesized a series of compounds, 2, in which a piperidine ring is linked directly to a quaternary amino acid center. Further improvement of in vitro activity was achieved by adding two carbon bridge in the piperidine ring, that is, tropane analogs 11. These improvements in activity are rationalized by X-ray crystallography analysis, which show that the tropane ring nitrogen atom moves into direct contact with Asp202 (arginase II numbering). The synthetic routes described here enabled the design of novel arginase inhibitors with improved potency and markedly different physico-chemical properties compared to ABH. Compound 11c represents the most in vitro active arginase inhibitor reported to date.

  10. Egr-1 and RNA POL II facilitate glioma cell GDNF transcription induced by histone hyperacetylation in promoter II.

    PubMed

    Zhang, Bao-Le; Guo, Ting-Wen; Gao, Le-Le; Ji, Guang-Quan; Gu, Xiao-He; Shao, Yu-Qi; Yao, Rui-Qin; Gao, Dian-Shuai

    2017-02-06

    The specific mechanisms for epigenetic regulation of gene transcription remain to be elucidated. We previously demonstrated that hyperacetylation of histone H3K9 in promoter II of glioma cells promotes high transcription of the glial cell line-derived neurotrophic factor (GDNF) gene. This hyperacetylation significantly enhanced Egr-1 binding and increased the recruitment of RNA polymerase II (RNA POL II) to that region (P < 0.05). Egr-1 expression was abnormally increased in C6 glioma cells. Further overexpression of Egr-1 significantly increased Egr-1 binding to GDNF promoter II, while increasing RNA POL II recruitment, thus increasing GDNF transcription (P < 0.01). When the acetylation of H3K9 in the Egr-1 binding site was significantly reduced by the histone acetyltransferase (HAT) inhibitor curcumin, binding of Egr-1 to GDNF promoter II, RNA POL II recruitment, and GDNF mRNA expression were significantly downregulated (P < 0.01). Moreover, curcumin attenuated the effects of Egr-1 overexpression on Egr-1 binding, RNA POL II recruitment, and GDNF transcription (P < 0.01). Egr-1 and RNA POL II co-existed in the nucleus of C6 glioma cells, with overlapping regions, but they were not bound to each other. In conclusion, highly expressed Egr-1 may be involved in the recruitment of RNA POL II in GDNF promoter II in a non-binding manner, and thereby involved in regulating GDNF transcription in high-grade glioma cells. This regulation is dependent on histone hyperacetylation in GDNF promoter II.

  11. Linagliptin: a novel methylxanthin based approved dipeptidyl peptidase-4 inhibitor.

    PubMed

    Agrawal, Ritesh; Jain, Pratima; Dikshit, S N

    2012-06-01

    Chemically, methylxanthine nucleus based Linagliptin (BI-1356, BI-1356-BS) is a dipeptidyl peptidase-IV inhibitor, which has been developed by Boehringer Ingelheim in association with Lilly for the treatment of Type-II Diabetes. Linagliptin was marketed by Lilly under the trade name Tradjenta and Trajenta. Linagliptin was approved as the once-daily dose by USFDA on 2 May 2011, for the treatment of Type-II Diabetes. Linagliptin 5mg once daily dose was approved based on a clinical trial program, which was conducted on approximately 4,000 adults with Type-II Diabetes. Linagliptin demonstrated statistically significant mean difference in HbA1c from placebo of up to 0.72 percent, when it was used monotherapically. In patients, who were not adequately controlled on metformin or metformin plus sulphonylurea, the addition of Linagliptin resulted in a statistically significant mean difference in HbA1c from placebo of -0.6 percent. Linagliptin was observed to produce significant reduction in fasting plasma glucose (FPG) compared to placebo, when used as a monotherapy in combination with metformin, sulfonylurea and/or pioglitazone. Linagliptin demonstrated significant reduction post-prandial glucose (PPG) levels in two hours as compared with placebo in monotherapy as well as in combination with metformin. In vitro assays also anticipated that Linagliptin is a potent DPPIV inhibitor as well as it exhibits good selectivity for DPP-IV as compared with other DPPs. The in-vivo studies also demonstrated same anticipation with respect to Linagliptin. Consequently, increasing the GLP-1 levels so far improved glucose tolerance in both healthy animals. X-ray crystallography anticipates that Linagliptin complexes with human DPPIV enzyme, e.g. butynyl substituent occupies the S1 hydrophobic pocket of the enzyme; the aminopiperidine substituent in the xanthine scaffold occupies the S2 subsite and its primary amine interacts with the key amino acid residues, which involves in the

  12. Quorum sensing inhibitors: an overview.

    PubMed

    Kalia, Vipin Chandra

    2013-01-01

    Excessive and indiscriminate use of antibiotics to treat bacterial infections has lead to the emergence of multiple drug resistant strains. Most infectious diseases are caused by bacteria which proliferate within quorum sensing (QS) mediated biofilms. Efforts to disrupt biofilms have enabled the identification of bioactive molecules produced by prokaryotes and eukaryotes. These molecules act primarily by quenching the QS system. The phenomenon is also termed as quorum quenching (QQ). In addition, synthetic compounds have also been found to be effective in QQ. This review focuses primarily on natural and synthetic quorum sensing inhibitors (QSIs) with the potential for treating bacterial infections. It has been opined that the most versatile prokaryotes to produce QSI are likely to be those, which are generally regarded as safe. Among the eukaryotes, certain legumes and traditional medicinal plants are likely to act as QSIs. Such findings are likely to lead to efficient treatments with much lower doses of drugs especially antibiotics than required at present.

  13. Protein farnesyltransferase inhibitors and progeria.

    PubMed

    Meta, Margarita; Yang, Shao H; Bergo, Martin O; Fong, Loren G; Young, Stephen G

    2006-10-01

    Genetic mutations that lead to an accumulation of farnesyl-prelamin A cause progeroid syndromes, including Hutchinson-Gilford progeria syndrome. It seemed possible that the farnesylated form of prelamin A might be toxic to mammalian cells, accounting for all the disease phenotypes that are characteristic of progeria. This concept led to the hypothesis that protein farnesyltransferase inhibitors (FTIs) might ameliorate the disease phenotypes of progeria in mouse models. Thus far, two different mouse models of progeria have been examined. In both models, FTIs improved progeria-like disease phenotypes. Here, prelamin A post-translational processing is discussed and several mutations underlying human progeroid syndromes are described. In addition, recent data showing that FTIs ameliorate disease phenotypes in a pair of mouse models of progeria are discussed.

  14. Macrocyclic Inhibitors of Hsp90

    PubMed Central

    Johnson, Victoria A.; Singh, Erinprit K.; Nazarova, Lidia A.; Alexander, Leslie D.; McAlpine, Shelli R.

    2011-01-01

    Heat shock proteins (HSP) are a family of highly conserved proteins, whose expression increases in response to stresses that may threaten cell survival. Over the past decade, heat shock protein 90 (Hsp90) has emerged as a potential therapeutic target for cancer as it plays a vital role in normal cell maturation and acts as a molecular chaperone for proper folding, assembly, and stabilization of many oncogenic proteins. To date, a majority of Hsp90 inhibitors that have been discovered are macrocycles. The relatively rigid conformation provided by the macrocyclic scaffold allows for a selective interaction with a biological target such as Hsp90. This review highlights the discovery and development of nine macro-cycles that inhibit the function of Hsp90, detailing their potency and the client proteins affected by Hsp90 inhibition. PMID:20536417

  15. 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.

  16. Checkpoint inhibitors in Hodgkin's lymphoma.

    PubMed

    Jezeršek Novaković, Barbara

    2016-04-01

    Hodgkin's lymphoma is unusual among cancers in that it consists of a small number of malignant Hodgkin/Reed-Sternberg cells in a sea of immune system cells, including T cells. Most of these T cells are reversibly inactivated in different ways and their reactivation may induce a very strong immune response to cancer cells. One way of reactivation of T cells is with antibodies blocking the CTLA-4 and especially with antibodies directed against PD-1 or the PD-L1 ligand thereby reversing the tumor-induced downregulation of T-cell function and augmenting antitumor immune activity at the priming (CTLA-4) or tissue effector (PD-1) phase. Immune checkpoint inhibitors have been evidenced as an additional treatment option with substantial effectiveness and acceptable toxicity in heavily pretreated patients with Hodgkin's lymphoma. Particularly, PD-1 blockade with nivolumab and pembrolizumab has demonstrated significant single-agent activity in this select population.

  17. 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.

  18. 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

  19. 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.

  20. Inhibitors of angiotensin-converting enzyme modulate mitosis and gene expression in pancreatic cancer cells

    SciTech Connect

    Reddy, M.K.; Baskaran, K.; Molteni, A.

    1995-12-01

    The angiotensin-converting enzyme (ACE) inhibitor captopril inhibits mitosis in several cell types that contain ACE and renin activity. In the present study, we evaluated the effect of the ACE inhibitors captopril and CGS 13945 (10{sup {minus}8} to 10{sup {minus}2}M) on proliferation and gene expression in hamster pancreatic duct carcinoma cells in culture. These cells lack renin and ACE activity. Both ACE inhibitors produced a dose-dependent reduction in tumor cell proliferation within 24 hr. Captopril at a concentration of 0.36 mM and CGS 13945 at 150 {mu}M decreased cellular growth rate to approximately half that of the control. Neither drug influenced the viability or the cell cycle distribution of the tumor cells. Slot blot analysis of mRNA for four genes, proliferation associated cell nuclear antigen (PCNA), K-ras, protein kinase C-{Beta} (PKC-{Beta}) and carbonic anhydrase II (CA II) was performed. Both ACE inhibitors increased K-ras expression by a factor of 2, and had no effect on CA II mRNA levels. Captopril also lowered PCNA by 40% and CGS 13945 lowered PKC-{Beta} gene expression to 30% of the control level. The data demonstrate that ACE inhibitors exhibit antimitotic activity and differential gene modulation in hamster pancreatic duct carcinoma cells. The absence of renin and ACE activity in these cells suggests that the antimitotic action of captopril and CGS 13945 is independent of renin-angiotensin regulation. The growth inhibition may occur through downregulation of growth-related gene expression. 27 refs., 5 figs.

  1. A Systems Pharmacology Perspective on the Clinical Development of Fatty Acid Amide Hydrolase Inhibitors for Pain

    PubMed Central

    Benson, N; Metelkin, E; Demin, O; Li, G L; Nichols, D; van der Graaf, P H

    2014-01-01

    The level of the endocannabinoid anandamide is controlled by fatty acid amide hydrolase (FAAH). In 2011, PF-04457845, an irreversible inhibitor of FAAH, was progressed to phase II clinical trials for osteoarthritic pain. This article discusses a prospective, integrated systems pharmacology model evaluation of FAAH as a target for pain in humans, using physiologically based pharmacokinetic and systems biology approaches. The model integrated physiological compartments; endocannabinoid production, degradation, and disposition data; PF-04457845 pharmacokinetics and pharmacodynamics, and cannabinoid receptor CB1-binding kinetics. The modeling identified clear gaps in our understanding and highlighted key risks going forward, in particular relating to whether methods are in place to demonstrate target engagement and pharmacological effect. The value of this modeling exercise will be discussed in detail and in the context of the clinical phase II data, together with recommendations to enable optimal future evaluation of FAAH inhibitors. PMID:24429592

  2. Role of neprilysin inhibitor combinations in hypertension: insights from hypertension and heart failure trials.

    PubMed

    Bavishi, Chirag; Messerli, Franz H; Kadosh, Bernard; Ruilope, Luis M; Kario, Kazuomi

    2015-08-07

    Neprilysin is a neutral endopeptidase and its inhibition increases bioavailability of natriuretic peptides, bradykinin, and substance P, resulting in natriuretic, vasodilatatory, and anti-proliferative effects. In concert, these effects are prone to produce a powerful ventricular unloading and antihypertensive response. LCZ696 (Valsartan/sacubitril) is a first-in-class angiotensin II-receptor neprilysin inhibitor. LCZ696 is a novel drug not only for the treatment of heart failure but it is also likely to be a useful antihypertensive drug and may have a preferential effect on systolic pressure. This review discusses (i) the mechanism of action, pharmacokinetics, and pharmacodynamics of this novel drug, (ii) the efficacy, safety, and tolerability of LCZ696 in treatment of hypertension from the available trials, (iii) evidence from other contemporary trials on combined Neprilysin inhibitors, (iv) future trials and areas of research to identify hypertensive patient populations that would most benefit from LCZ696.

  3. Panobinostat (LBH589): a potent pan-deacetylase inhibitor with promising activity against hematologic and solid tumors.

    PubMed

    Prince, H Miles; Bishton, Mark J; Johnstone, Ricky W

    2009-06-01

    The deacetylase inhibitors are a structurally diverse class of targeted antineoplastic agents that have demonstrated in vitro and in vivo preclinical activity in a wide range of malignancies. Based on this preclinical activity, several deacetylase inhibitors have undergone rapid clinical development in recent years. Among these, the deacetylase inhibitor panobinostat is one of the most widely studied, with extensive pharmacokinetic, pharmacodynamic and dose-finding data available across a wide variety of hematologic and solid tumors. Furthermore, panobinostat has demonstrated favorable clinical activity against various hematologic malignancies, most notably lymphomas and myeloid malignancies in Phase I and II studies. In this article, we discuss the preclinical data on panobinostat and emerging data from Phase I and II studies in cancer patients.

  4. Mechanism-based inhibitors for the inactivation of the bacterial phosphotriesterase.

    PubMed

    Hong, S B; Mullins, L S; Shim, H; Raushel, F M

    1997-07-22

    1-Bromovinyl (I), Z-2-bromovinyl (II), 1,2-dibromoethyl (III), and a series of 4-(halomethyl)-2-nitrophenyl (IVa-c) diethyl phosphate esters were examined as substrates and mechanism-based inhibitors for the bacterial phosphotriesterase. All of these compounds were found to act as substrates for the enzyme. Inhibitor I rapidly inactivated the enzyme within 1 min, giving a partition ratio of 230. The newly formed covalent adduct with inhibitor I was susceptible to hydrolysis at elevated values of pH and dissociation by NH2OH. Azide was not able to protect the enzyme from inactivation with inhibitor I, implying that the reactive species was not released into solution prior to the inactivation event. The reactive species was proposed to be either an acyl bromide or a ketene intermediate formed by the enzymatic hydrolysis of inhibitor I. Compounds II and III were shown to be relatively poor substrates of phosphotriesterase and they did not induce any significant inactivation of the enzyme. The inhibitor, 4-(bromomethyl)-2-nitrophenyl diethyl phosphate (IVa), was found to irreversibly inactivate the enzyme with a KI = 7.9 mM and kinact = 1. 2 min-1 at pH 9.0. There was no effect on the rate of inactivation upon the addition of the exogenous nucleophiles, azide, and NH2OH. The species responsible for the covalent modification of the enzyme by IVa was most likely a quinone methide formed by the elimination of bromide from the phenolic intermediate. NMR experiments demonstrated that the quinone methide did not accumulate in solution. The chloro (IVb) and fluoro (IVc) analogues did not inactivate the enzyme. These results suggest that the elimination of the halide ion from the phenolic intermediate largely determines the partition ratio for inactivation.

  5. Avibactam and Inhibitor-Resistant SHV β-Lactamases

    PubMed Central

    Winkler, Marisa L.; Papp-Wallace, Krisztina M.; Taracila, Magdalena A.

    2015-01-01

    β-Lactamase enzymes (EC 3.5.2.6) are a significant threat to the continued use of β-lactam antibiotics to treat infections. A novel non-β-lactam β-lactamase inhibitor with activity against many class A and C and some class D β-lactamase variants, avibactam, is now available in the clinic in partnership with ceftazidime. Here, we explored the activity of avibactam against a variety of characterized isogenic laboratory constructs of β-lactamase inhibitor-resistant variants of the class A enzyme SHV (M69I/L/V, S130G, K234R, R244S, and N276D). We discovered that the S130G variant of SHV-1 shows the most significant resistance to inhibition by avibactam, based on both microbiological and biochemical characterizations. Using a constant concentration of 4 mg/liter of avibactam as a β-lactamase inhibitor in combination with ampicillin, the MIC increased from 1 mg/liter for blaSHV-1 to 256 mg/liter for blaSHV S130G expressed in Escherichia coli DH10B. At steady state, the k2/K value of the S130G variant when inactivated by avibactam was 1.3 M−1 s−1, versus 60,300 M−1 s−1 for the SHV-1 β-lactamase. Under timed inactivation conditions, we found that an approximately 1,700-fold-higher avibactam concentration was required to inhibit SHV S130G than the concentration that inhibited SHV-1. Molecular modeling suggested that the positioning of amino acids in the active site of SHV may result in an alternative pathway of inactivation when complexed with avibactam, compared to the structure of CTX-M-15–avibactam, and that S130 plays a role in the acylation of avibactam as a general acid/base. In addition, S130 may play a role in recyclization. As a result, we advance that the lack of a hydroxyl group at position 130 in the S130G variant of SHV-1 substantially slows carbamylation of the β-lactamase by avibactam by (i) removing an important proton acceptor and donator in catalysis and (ii) decreasing the number of H bonds. In addition, recyclization is most likely

  6. 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.

  7. Intellectual property issues of immune checkpoint inhibitors

    PubMed Central

    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

  8. Discovery of novel heterocyclic factor VIIa inhibitors.

    PubMed

    Rai, Roopa; Kolesnikov, Aleksandr; Sprengeler, Paul A; Torkelson, Steven; Ton, Tony; Katz, Bradley A; Yu, Christine; Hendrix, John; Shrader, William D; Stephens, Robin; Cabuslay, Ronnell; Sanford, Ellen; Young, Wendy B

    2006-04-15

    Structure-activity relationships and binding mode of novel heterocyclic factor VIIa inhibitors will be described. In these inhibitors, a highly basic 5-amidinoindole moiety has been successfully replaced with a less basic 5-aminopyrrolo[3,2-b]pyridine scaffold.

  9. Rust inhibitor and oil composition containing same

    SciTech Connect

    Bialy, J.J.; Cullen, W.P.; Dorn, P.; Nebzydoski, J.W.; Sung, R.L.

    1981-04-21

    A rust inhibitor comprising the reaction product of a hydrocarbylsuccinic anhydride in which the hydrocarbyl radical has from about 6 to 30 carbon atoms and an aminotriazole is provided. The rust inhibitor is effective in motor fuel and lubricating oil compositions.

  10. Novel tricyclics (e.g., GSK945237) as potent inhibitors of bacterial type IIA topoisomerases.

    PubMed

    Miles, Timothy J; Hennessy, Alan J; Bax, Ben; Brooks, Gerald; Brown, Barry S; Brown, Pamela; Cailleau, Nathalie; Chen, Dongzhao; Dabbs, Steven; Davies, David T; Esken, Joel M; Giordano, Ilaria; Hoover, Jennifer L; Jones, Graham E; Kusalakumari Sukmar, Senthill K; Markwell, Roger E; Minthorn, Elisabeth A; Rittenhouse, Steve; Gwynn, Michael N; Pearson, Neil D

    2016-05-15

    During the course of our research on the lead optimisation of the NBTI (Novel Bacterial Type II Topoisomerase Inhibitors) class of antibacterials, we discovered a series of tricyclic compounds that showed good Gram-positive and Gram-negative potency. Herein we will discuss the various subunits that were investigated in this series and report advanced studies on compound 1 (GSK945237) which demonstrates good PK and in vivo efficacy properties.

  11. The synthesis of ethacrynic acid thiazole derivatives as glutathione S-transferase pi inhibitors.

    PubMed

    Li, Ting; Liu, Guyue; Li, Hongcai; Yang, Xinmei; Jing, Yongkui; Zhao, Guisen

    2012-04-01

    Glutathione S-transferase pi (GSTpi) is a phase II enzyme which protects cells from death and detoxifies chemotherapeutic agents in cancer cells. Ethacrynic acid (EA) is a weak GSTpi inhibitor. Structure modifications were done to improve the ability of EA to inhibit GSTpi activity. Eighteen EA thiazole derivatives were designed and synthesized. Compounds 9a, 9b and 9c with a replacement of carboxyl group of EA by a heterocyclic thiazole exhibited improvement over EA to inhibit GSTpi activity.

  12. Protease inhibitor homologues from mamba venoms: facilitation of acetylcholine release and interactions with prejunctional blocking toxins.

    PubMed

    Harvey, A L; Karlsson, E

    1982-09-01

    1 Five polypeptides, which were isolated from elapid snake venoms and which are structurally related to protease inhibitors, were tested for action on isolated biventer cervicis nerve-muscle preparations of the chick. 2 Dendrotoxin from the Eastern green mamba (Dendroaspis angusticeps) and toxins K and I from the black mamba (Dendroaspis polylepis polylepis) increased to indirect stimulation without affecting responses to exogenous acetylcholine, carbachol of KCl. 3 The two other protease inhibitor homologues, HHV-II from Ringhals cobra (Hemachatus haemachatus) and NNV-II from Cape cobra (Naja nivea) did not increase responses to nerve stimulation. Trypsin inhibitor from bovine pancreas also had no facilitatory effects on neuromuscular transmission. 4 The facilitatory toxins from mamba venoms interacted with the prejunctional blocking toxins, beta-bungarotoxin, crotoxin and notexin, but not with taipoxin. The blocking effects of beta-bungarotoxin were reduced by pretreatment with the mamba toxins, whereas the blocking actions of crotoxin and notexin were enhanced. 5 The results indicate that protease inhibitor homologues from mamba venoms form a new class of neurotoxin, which acts to increase the release of acetylcholine in response to motor nerve stimulation. 6 From the interaction studies it is concluded that the facilitatory toxins bind to motor nerve terminals at sites related to those occupied by the prejunctional blocking toxins. However, differences in interactions with individual toxins suggest that there must be several related binding sites on the nerve terminals.

  13. Induction of autophagy by proteasome inhibitor is associated with proliferative arrest in colon cancer cells

    SciTech Connect

    Wu, William Ka Kei Wu Yachun; Yu Le; Li Zhijie; Sung, Joseph Jao Yiu; Cho, C.H.

    2008-09-19

    The ubiquitin-proteasome system (UPS) and lysosome-dependent macroautophagy (autophagy) are two major intracellular pathways for protein degradation. Blockade of UPS by proteasome inhibitors has been shown to activate autophagy. Recent evidence also suggests that proteasome inhibitors may inhibit cancer growth. In this study, the effect of a proteasome inhibitor MG-132 on the proliferation and autophagy of cultured colon cancer cells (HT-29) was elucidated. Results showed that MG-132 inhibited HT-29 cell proliferation and induced G{sub 2}/M cell cycle arrest which was associated with the formation of LC3{sup +} autophagic vacuoles and the accumulation of acidic vesicular organelles. MG-132 also increased the protein expression of LC3-I and -II in a time-dependent manner. In this connection, 3-methyladenine, a Class III phosphoinositide 3-kinase inhibitor, significantly abolished the formation of LC3{sup +} autophagic vacuoles and the expression of LC3-II but not LC3-I induced by MG-132. Taken together, this study demonstrates that inhibition of proteasome in colon cancer cells lowers cell proliferation and activates autophagy. This discovery may shed a new light on the novel function of proteasome in the regulation of autophagy and proliferation in colon cancer cells.

  14. Exploring the scaffold universe of kinase inhibitors.

    PubMed

    Hu, Ye; Bajorath, Jürgen

    2015-01-08

    The scaffold concept was applied to systematically determine, analyze, and compare core structures of kinase inhibitors. From publicly available inhibitors of the human kinome, scaffolds and cyclic skeletons were systematically extracted and organized taking activity data, structural relationships, and retrosynthetic criteria into account. Scaffold coverage varied greatly across the kinome, and many scaffolds representing compounds with different activity profiles were identified. The majority of kinase inhibitor scaffolds were involved in well-defined yet distinct structural relationships, which had different consequences on compound activity. Scaffolds exclusively representing highly potent compounds were identified as well as structurally analogous scaffolds with very different degrees of promiscuity. Scaffold relationships presented herein suggest a variety of hypotheses for inhibitor design. Our detailed organization of the kinase inhibitor scaffold universe with respect to different activity and structural criteria, all scaffolds, and the original compound data assembled for our analysis are made freely available.

  15. Kinetics of inhibition by 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole on calf thymus casein kinase II.

    PubMed

    Zandomeni, R O

    1989-09-01

    The adenosine analogue 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) is a specific inhibitor for RNA polymerase II transcription in vivo and in vitro [Tamm + Sehgal (1978) Adv. Virus Res. 22, 187-258; Zandomeni & Weinmann (1984) J. Biol. Chem. 259, 14804-14811]. The effect on RNA polymerase II-specific transcription seems to be mediated by its inhibition of nuclear casein kinase II [Zandomeni, Carrera-Zandomeni, Shugar & Weinmann (1986) J. Biol. Chem. 261, 3414-3419]. Inhibition studies indicated that DRB acted as a mixed-type inhibitor with respect to casein and as a competitive inhibitor with respect to the nucleotide phosphate donor substrates. The DRB inhibition constant is 7 microM for the calf thymus casein kinase II, with regard to both ATP and GTP.

  16. Design of the INHIBIT trial: preventing inhibitors by avoiding ‘danger’, prolonging half-life and promoting tolerance

    PubMed Central

    Ragni, Margaret V; Malec, Lynn M

    2015-01-01

    Inhibitor formation is among the most serious complications of hemophilia treatment. With the US FDA licensure of the novel long-lasting recombinant factor VIII (FVIII) Fc fusion protein, Eloctate, which prolongs FVIII half-life, we propose an innovative approach to prevent inhibitor formation. In this paper, we describe a multicenter, Phase II, single-arm, 48-week trial, the INHIBIT trial, to determine if Eloctate, begun before a bleed and continued as once weekly prophylaxis, will reduce inhibitor formation in children with hemophilia A. We hypothesize that avoiding ‘danger,’ that is, immune activation by a bleed at first factor exposure and prolonging FVIII half-life will prevent inhibitors and promote FVIII-specific T-cell tolerance. If successful, this approach will suggest a new paradigm in clinical practice. PMID:25374055

  17. World War II Homefront.

    ERIC Educational Resources Information Center

    Garcia, Rachel

    2002-01-01

    Presents an annotated bibliography that provides Web sites focusing on the U.S. homefront during World War II. Covers various topics such as the homefront, Japanese Americans, women during World War II, posters, and African Americans. Includes lesson plan sources and a list of additional resources. (CMK)

  18. 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

  19. Autoantibodies directed against the protease inhibitor calpastatin in psoriasis

    PubMed Central

    Matsushita, Y; Shimada, Y; Kawara, S; Takehara, K; Sato, S

    2005-01-01

    Psoriasis is believed to be a T cell-mediated autoimmune disease, but also exhibits autoantibody production. Calpastatin is an endogenous inhibitor of calpain, a ubiquitous protease that regulates inflammatory processes. Anti-calpastatin autoantibody was first identified as an autoantibody specific to rheumatoid arthritis, but has been also detected in other autoimmune diseases. In this study, we examined the presence and levels of anti-calpastatin antibody in 77 psoriasis patients by enzyme-linked immunosorbent assay. Compared with normal controls, psoriasis patients exhibited significantly elevated IgG anti-calpastatin antibody levels that were similar to those found in rheumatoid arthritis patients. Remarkably, IgG anti-calpastatin autoantibody in sera from psoriasis patients inhibited calpastatin activity. Calpain II expression was up-regulated in psoriasis skin lesions compared with normal skin while calpastatin expression was normal. The results of this study reveal the presence of anti-calpastatin autoantibody in psoriasis. PMID:15654835

  20. Tivozanib: a novel VGFR inhibitor for kidney cancer.

    PubMed

    Boyle, Helen

    2013-06-01

    Treatment of kidney cancer has changed over the past 10 years with the approval of several targeted agents. These drugs are given on a long term base and toxicity is an issue for most patients. Despite improvement compared to immunotherapy, most patients will progress on these drugs. There is a need for more portent and better tolerated drugs. Tivozanib is a potent pan VEGR specific inhibitor. In this phase II trial it gave interesting results with an overall median PFS throughout the study of 11.7 months (95% CI: 8.3-14.3 months) and an overall objective response rate of 24% (95% CI: 19-30%). "Off"-target toxicity was mild.