Sample records for formation inhibitors synthesis
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Vasileiou, Zoe; Barlos, Kostas K; Gatos, Dimitrios; Adermann, Knut; Deraison, Celine; Barlos, Kleomenis
2010-01-01
Proteinase inhibitors are of high pharmaceutical interest and are drug candidates for a variety of indications. Specific kallikrein inhibitors are important for their antitumor activity and their potential application to the treatment of skin diseases. In this study we describe the synthesis of domain 6 of the kallikrein inhibitor Lympho-Epithilial Kazal-Type Inhibitor (LEKTI) by the fragment condensation method and site-directed cystine bridge formation. To obtain the linear LEKTI precursor, the condensation was best performed in solution, coupling the protected fragment 1-22 to 23-68. This method yielded LEKTI domain 6 of high purity and equipotent to the recombinantly produced peptide. (c) 2010 Wiley Periodicals, Inc.
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Benzoylurea Chitin Synthesis Inhibitors.
Sun, Ranfeng; Liu, Chunjuan; Zhang, Hao; Wang, Qingmin
2015-08-12
Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure-activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs.
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DNA synthesis inhibitors for the treatment of gastrointestinal cancer.
Yasui, Hiroshi; Tsurita, Giichiro; Imai, Kohzoh
2014-11-01
Intensive laboratory, preclinical and clinical studies have identified and validated molecular targets in cancers, leading to a shift toward the development of novel, rationally designed and specific therapeutic agents. However, gastrointestinal cancers continue to have a poor prognosis, largely due to drug resistance. Here, we discuss the current understanding of DNA synthesis inhibitors and their mechanisms of action for the treatment of gastrointestinal malignancies. Conventional agents, including DNA synthesis inhibitors such as fluoropyrimidines and platinum analogs, remain the most effective therapeutics and are the standards against which new drugs are compared. Novel DNA synthesis inhibitors for the treatment of gastrointestinal malignancies include a combination of the antimetabolite TAS-102, which consists of trifluorothymidine with a thymidine phosphorylase inhibitor, and a novel micellar formulation of cisplatin NC-6004 that uses a nanotechnology-based drug delivery system. The challenges of translational cancer research using DNA synthesis inhibitors include the identification of drugs that are specific to tumor cells to reduce toxicity and increase antitumor efficacy, biomarkers to predict pharmacological responses to chemotherapeutic drugs, identification of ways to overcome drug resistance and development of novel combination therapies with DNA synthesis inhibitors and other cancer therapies, such as targeted molecular therapeutics. Here, we discuss the current understanding of DNA synthesis inhibitors and their mechanisms of action for the treatment of gastrointestinal malignancies.
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Synthesis and Application of Pyrrolidone-containing Shale Inhibitors
NASA Astrophysics Data System (ADS)
Liu, Yonggui; Hou, Jie; Zhang, Yang; Yan, Jing; Song, Tao; Xu, Yongjun
2018-03-01
New generation polyamine inhibitors are amino-terminated polyethers with excellent inhibiting capabilities; they play a key role in borehole stabilization and reservoir protection. However, polyamine inhibitors are limited by their poor thermal stability, which can be attributed to the presence of ether bonds in their molecular structures. We propose a three-step synthesis approach fora novel pyrrolidone-containing polyamine inhibitor (DYNP) by introducing N-vinyl-2-pyrrolidone (NVP) on divinyloxyethane. This polyamine inhibitor exhibits an optimized molecular structure and has enhanced heat resistance. Characterizations by infrared (IR) spectroscopy and evaluation tests demonstrate several advantages of DYNP inhibitors, including excellent inhibiting capability (superior to similar materials such as polyamines), improved heat resistance (reasonable stability at temperatures up to 240°C), and good compatibility with both fresh water and salt water drilling fluids. These can be attributed to the presence of considerable amounts of amino groups in the repeating unit of DYNP molecules. The DYNP inhibitor was applied in over 20 boreholes in tight oil blocks in Daqing Oilfield to relieve hydration of formations with high shale contents. For instance, drilling in the 2033.5m horizontal section of Dragon 2 borehole was smooth, with a borehole diameter expansion ratio below 10%.
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The differential role of cortical protein synthesis in taste memory formation and persistence
NASA Astrophysics Data System (ADS)
Levitan, David; Gal-Ben-Ari, Shunit; Heise, Christopher; Rosenberg, Tali; Elkobi, Alina; Inberg, Sharon; Sala, Carlo; Rosenblum, Kobi
2016-05-01
The current dogma suggests that the formation of long-term memory (LTM) is dependent on protein synthesis but persistence of the memory trace is not. However, many of the studies examining the effect of protein synthesis inhibitors (PSIs) on LTM persistence were performed in the hippocampus, which is known to have a time-dependent role in memory storage, rather than the cortex, which is considered to be the main structure to store long-term memories. Here we studied the effect of PSIs on LTM formation and persistence in male Wistar Hola (n⩾5) rats by infusing the protein synthesis inhibitor, anisomycin (100 μg, 1 μl), into the gustatory cortex (GC) during LTM formation and persistence in conditioned taste aversion (CTA). We found that local anisomycin infusion to the GC before memory acquisition impaired LTM formation (P=8.9E-5), but had no effect on LTM persistence when infused 3 days post acquisition (P=0.94). However, when we extended the time interval between treatment with anisomycin and testing from 3 days to 14 days, LTM persistence was enhanced (P=0.01). The enhancement was on the background of stable and non-declining memory, and was not recapitulated by another amnesic agent, APV (10 μg, 1 μl), an N-methyl-D-aspartate receptor antagonist (P=0.54). In conclusion, CTA LTM remains sensitive to the action of PSIs in the GC even 3 days following memory acquisition. This sensitivity is differentially expressed between the formation and persistence of LTM, suggesting that increased cortical protein synthesis promotes LTM formation, whereas decreased protein synthesis promotes LTM persistence.
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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.
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VCP and ATL1 regulate endoplasmic reticulum and protein synthesis for dendritic spine formation
Shih, Yu-Tzu; Hsueh, Yi-Ping
2016-01-01
Imbalanced protein homeostasis, such as excessive protein synthesis and protein aggregation, is a pathogenic hallmark of a range of neurological disorders. Here, using expression of mutant proteins, a knockdown approach and disease mutation knockin mice, we show that VCP (valosin-containing protein), together with its cofactor P47 and the endoplasmic reticulum (ER) morphology regulator ATL1 (Atlastin-1), regulates tubular ER formation and influences the efficiency of protein synthesis to control dendritic spine formation in neurons. Strengthening the significance of protein synthesis in dendritic spinogenesis, the translation blocker cyclohexamide and the mTOR inhibitor rapamycin reduce dendritic spine density, while a leucine supplement that increases protein synthesis ameliorates the dendritic spine defects caused by Vcp and Atl1 deficiencies. Because VCP and ATL1 are the causative genes of several neurodegenerative and neurodevelopmental disorders, we suggest that impaired ER formation and inefficient protein synthesis are significant in the pathogenesis of multiple neurological disorders. PMID:26984393
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VCP and ATL1 regulate endoplasmic reticulum and protein synthesis for dendritic spine formation.
Shih, Yu-Tzu; Hsueh, Yi-Ping
2016-03-17
Imbalanced protein homeostasis, such as excessive protein synthesis and protein aggregation, is a pathogenic hallmark of a range of neurological disorders. Here, using expression of mutant proteins, a knockdown approach and disease mutation knockin mice, we show that VCP (valosin-containing protein), together with its cofactor P47 and the endoplasmic reticulum (ER) morphology regulator ATL1 (Atlastin-1), regulates tubular ER formation and influences the efficiency of protein synthesis to control dendritic spine formation in neurons. Strengthening the significance of protein synthesis in dendritic spinogenesis, the translation blocker cyclohexamide and the mTOR inhibitor rapamycin reduce dendritic spine density, while a leucine supplement that increases protein synthesis ameliorates the dendritic spine defects caused by Vcp and Atl1 deficiencies. Because VCP and ATL1 are the causative genes of several neurodegenerative and neurodevelopmental disorders, we suggest that impaired ER formation and inefficient protein synthesis are significant in the pathogenesis of multiple neurological disorders.
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Lamb, Rebecca; Harrison, Hannah; Smith, Duncan L.; Townsend, Paul A.; Jackson, Thomas; Ozsvari, Bela; Martinez-Outschoorn, Ubaldo E.; Pestell, Richard G.; Howell, Anthony; Lisanti, Michael P.; Sotgia, Federica
2015-01-01
We have used an unbiased proteomic profiling strategy to identify new potential therapeutic targets in tumor-initiating cells (TICs), a.k.a., cancer stem cells (CSCs). Towards this end, the proteomes of mammospheres from two breast cancer cell lines were directly compared to attached monolayer cells. This allowed us to identify proteins that were highly over-expressed in CSCs and/or progenitor cells. We focused on ribosomal proteins and protein folding chaperones, since they were markedly over-expressed in mammospheres. Overall, we identified >80 molecules specifically associated with protein synthesis that were commonly upregulated in mammospheres. Most of these proteins were also transcriptionally upregulated in human breast cancer cells in vivo, providing evidence for their potential clinical relevance. As such, increased mRNA translation could provide a novel mechanism for enhancing the proliferative clonal expansion of TICs. The proteomic findings were functionally validated using known inhibitors of protein synthesis, via three independent approaches. For example, puromycin (which mimics the structure of tRNAs and competitively inhibits protein synthesis) preferentially targeted CSCs in both mammospheres and monolayer cultures, and was ~10-fold more potent for eradicating TICs, than “bulk” cancer cells. In addition, rapamycin, which inhibits mTOR and hence protein synthesis, was very effective at reducing mammosphere formation, at nanomolar concentrations. Finally, mammosphere formation was also markedly inhibited by methionine restriction, which mimics the positive effects of caloric restriction in cultured cells. Remarkably, mammosphere formation was >18-fold more sensitive to methionine restriction and replacement, as directly compared to monolayer cell proliferation. Methionine is absolutely required for protein synthesis, since every protein sequence starts with a methionine residue. Thus, the proliferation and survival of CSCs is very sensitive to
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PROTEASOME INHIBITOR TREATMENT REDUCED FATTY ACID, TRIACYLGLYCEROL AND CHOLESTEROL SYNTHESIS
Oliva, Joan; French, Samuel W.; Li, Jun; Bardag-Gorce, Fawzia
2014-01-01
In the present study, the beneficial effects of proteasome inhibitor treatment in reducing ethanol-induced steatosis were investigated. A microarray analysis was performed on the liver of rats injected with PS-341 (Bortezomib, Velcade®), and the results showed that proteasome inhibitor treatment significantly reduced the mRNA expression of SREBP-1c, and the downstream lipogenic enzymes, such as fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC), which catalyzes the carboxylation of acetyl-CoA to malonyl-CoA, the rate-limiting step in fatty acid synthesis. ELOVL6, which is responsible for fatty acids long chain elongation, was also significantly down regulated by proteasome inhibitor treatment. Moreover, PS-341 administration significantly reduced the expression of acyl-glycerol-3-phosphate acyltransferase (AGPAT), and diacylglycerol acyltransferase (DGAT), enzyme involved in triacylglycerol (TAG) synthesis. Finally, PS-341 was found to down regulate the enzymes 3-hydroxy-3-methylglutaryl-CoenzymeA synthase (HMG-CoA synthase) that is responsible for cholesterol synthesis. Proteasome inhibitor was also found to play a role in intestinal lipid adsorption because apolipoproteins A (apoA-I, apoAII, apoA-IV and ApoCIII) were down regulated by proteasome inhibitor treatment, especially ApoA-II that is known to be a marker of alcohol consumption. Proteasome inhibitor treatment also decreased apobec-1 complementation factor (ACF) leading to lower level of editing and production of ApoB protein. Moreover apolipoprotein C-III, a major component of chylomicrons was significantly down regulated. However, lipoprotein lipase (Lpl) and High density lipoprotein binding protein (Hdlbp) mRNA levels were increased by proteasome inhibitor treatment. These results suggested that proteasome inhibitor treatment could be used to reduce the alcohol-enhanced lipogenesis and alcohol-induced liver steatosis. A morphologic analysis, performed on the liver of rats fed ethanol for one
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Design and Synthesis of 4-Heteroaryl 1,2,3,4-Tetrahydroisoquinolines as Triple Reuptake Inhibitors
2014-01-01
A series of 4-bicyclic heteroaryl 1,2,3,4-tetrahydroisoquinoline inhibitors of the serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT) was discovered. The synthesis and structure–activity relationship (SAR) of these triple reuptake inhibitors (TRIs) will be discussed. Compound 10i (AMR-2), a very potent inhibitor of SERT, NET, and DAT, showed efficacy in the rat forced-swim and mouse tail suspension models with minimum effective doses of 0.3 and 1 mg/kg (po), respectively. At efficacious doses in these assays, 10i exhibited substantial occupancy levels at the three transporters in both rat and mouse brain. The study of the metabolism of 10i revealed the formation of a significant active metabolite, compound 13. PMID:25050161
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Design and synthesis of 4-heteroaryl 1,2,3,4-tetrahydroisoquinolines as triple reuptake inhibitors.
Liu, Shuang; Zha, Congxiang; Nacro, Kassoum; Hu, Min; Cui, Wenge; Yang, Yuh-Lin; Bhatt, Ulhas; Sambandam, Aruna; Isherwood, Matthew; Yet, Larry; Herr, Michael T; Ebeltoft, Sarah; Hassler, Carla; Fleming, Linda; Pechulis, Anthony D; Payen-Fornicola, Anne; Holman, Nicholas; Milanowski, Dennis; Cotterill, Ian; Mozhaev, Vadim; Khmelnitsky, Yuri; Guzzo, Peter R; Sargent, Bruce J; Molino, Bruce F; Olson, Richard; King, Dalton; Lelas, Snjezana; Li, Yu-Wen; Johnson, Kim; Molski, Thaddeus; Orie, Anitra; Ng, Alicia; Haskell, Roy; Clarke, Wendy; Bertekap, Robert; O'Connell, Jonathan; Lodge, Nicholas; Sinz, Michael; Adams, Stephen; Zaczek, Robert; Macor, John E
2014-07-10
A series of 4-bicyclic heteroaryl 1,2,3,4-tetrahydroisoquinoline inhibitors of the serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT) was discovered. The synthesis and structure-activity relationship (SAR) of these triple reuptake inhibitors (TRIs) will be discussed. Compound 10i (AMR-2), a very potent inhibitor of SERT, NET, and DAT, showed efficacy in the rat forced-swim and mouse tail suspension models with minimum effective doses of 0.3 and 1 mg/kg (po), respectively. At efficacious doses in these assays, 10i exhibited substantial occupancy levels at the three transporters in both rat and mouse brain. The study of the metabolism of 10i revealed the formation of a significant active metabolite, compound 13.
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Lee, Kyeong; Lee, Jee-Hyun; Boovanahalli, Shanthaveerappa K; Choi, Yongseok; Choo, Soo-Jin; Yoo, Ick-dong; Kim, Dong Hee; Yun, Mi Young; Lee, Gye Won; Song, Gyu-Yong
2010-12-01
We report the synthesis of a novel series of highly potent melanin inhibitors which were obtained through structural modification of an anticancer compound S-(+)-decursinol. The in vitro inhibitory potencies of the newly synthesized compounds were evaluated against α-MSH induced melanin production in B16 murine melanoma cells. Among the compounds evaluated, compounds 2, 3, 6b, 7a, 7b, 8a and 8b emerged as highly potent inhibitors of melanin production. Besides, these compounds demonstrated significantly low cytotoxicity. Copyright © 2010 Elsevier Masson SAS. All rights reserved.
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Synthesis and Evaluation of Novel RSK Inhibitors in a Living Human Breast Model
2015-09-01
the n- propyl carbamate analogue 9, and the sec-butyl carbamate analogue 10. The modified synthetic route could also be applied to the synthesis of...AWARD NUMBER: W81XWH-11-1-0068 TITLE: Synthesis and Evaluation of Novel RSK Inhibitors in a Living Human Breast Model PRINCIPAL INVESTIGATOR...DATES COVERED 01 Jul 2011 – 30 Jun 2015 4. TITLE AND SUBTITLE Synthesis and Evaluation of Novel RSK Inhibitors in a Living Human Breast Model 5a
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Synthesis of the Pitstop family of clathrin inhibitors.
Robertson, Mark J; Deane, Fiona M; Stahlschmidt, Wiebke; von Kleist, Lisa; Haucke, Volker; Robinson, Phillip J; McCluskey, Adam
2014-07-01
This protocol describes the synthesis of two classes of clathrin inhibitors, Pitstop 1 and Pitstop 2, along with two inactive analogs that can be used as negative controls (Pitstop inactive controls, Pitnot-2 and Pitnot-2-100). Pitstop-induced inhibition of clathrin TD function acutely interferes with clathrin-mediated endocytosis (CME), synaptic vesicle recycling and cellular entry of HIV, whereas clathrin-independent internalization pathways and secretory traffic proceed unperturbed; these reagents can, therefore, be used to investigate clathrin function, and they have potential pharmacological applications. Pitstop 1 is synthesized in two steps: sulfonation of 1,8-naphthalic anhydride and subsequent reaction with 4-amino(methyl)aniline. Pitnot-1 results from the reaction of 4-amino(methyl)aniline with commercially available 4-sulfo-1,8-naphthalic anhydride potassium salt. Reaction of 1-naphthalene sulfonyl chloride with pseudothiohydantoin followed by condensation with 4-bromobenzaldehyde yields Pitstop 2. The synthesis of the inactive control commences with the condensation of 4-bromobenzaldehyde with the rhodanine core. Thioketone methylation and displacement with 1-napthylamine affords the target compound. Although Pitstop 1-series compounds are not cell permeable, they can be used in biochemical assays or be introduced into cells via microinjection. The Pitstop 2-series compounds are cell permeable. The synthesis of these compounds does not require specialist equipment and can be completed in 3-4 d. Microwave irradiation can be used to reduce the synthesis time. The synthesis of the Pitstop 2 family is easily adaptable to enable the synthesis of related compounds such as Pitstop 2-100 and Pitnot-2-100. The procedures are also simple, efficient and amenable to scale-up, enabling cost-effective in-house synthesis for users of these inhibitor classes.
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Najumudeen, Arafath K; Posada, Itziar M D; Lectez, Benoit; Zhou, Yong; Landor, Sebastian K-J; Fallarero, Adyary; Vuorela, Pia; Hancock, John; Abankwa, Daniel
2015-12-15
Ras isoforms H-, N-, and K-ras are each mutated in specific cancer types at varying frequencies and have different activities in cell fate control. On the plasma membrane, Ras proteins are laterally segregated into isoform-specific nanoscale signaling hubs, termed nanoclusters. As Ras nanoclusters are required for Ras signaling, chemical modulators of nanoclusters represent ideal candidates for the specific modulation of Ras activity in cancer drug development. We therefore conducted a chemical screen with commercial and in-house natural product libraries using a cell-based H-ras-nanoclustering FRET assay. Next to established Ras inhibitors, such as a statin and farnesyl-transferase inhibitor, we surprisingly identified five protein synthesis inhibitors as positive regulators. Using commonly employed cycloheximide as a representative compound, we show that protein synthesis inhibition increased nanoclustering and effector recruitment specifically of active H-ras but not of K-ras. Consistent with these data, cycloheximide treatment activated both Erk and Akt kinases and specifically promoted H-rasG12V-induced, but not K-rasG12V-induced, PC12 cell differentiation. Intriguingly, cycloheximide increased the number of mammospheres, which are enriched for cancer stem cells. Depletion of H-ras in combination with cycloheximide significantly reduced mammosphere formation, suggesting an exquisite synthetic lethality. The potential of cycloheximide to promote tumor cell growth was also reflected in its ability to increase breast cancer cell tumors grown in ovo. These results illustrate the possibility of identifying Ras-isoform-specific modulators using nanocluster-directed screening. They also suggest an unexpected feedback from protein synthesis inhibition to Ras signaling, which might present a vulnerability in certain tumor cell types.
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Rapid synthesis of triazine inhibitors of inosine monophosphate dehydrogenase.
Pitts, William J; Guo, Junqing; Dhar, T G Murali; Shen, Zhongqi; Gu, Henry H; Watterson, Scott H; Bednarz, Mark S; Chen, Bang Chi; Barrish, Joel C; Bassolino, Donna; Cheney, Daniel; Fleener, Catherine A; Rouleau, Katherine A; Hollenbaugh, Diane L; Iwanowicz, Edwin J
2002-08-19
A series of novel triazine-based small molecule inhibitors (IV) of inosine monophosphate dehydrogenase was prepared. The synthesis and the structure-activity relationships (SAR) derived from in vitro studies are described.
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Ingersoll, E P; Wilt, F H
1998-04-01
The primary mesenchyme cells of the sea urchin embryo construct an elaborate calcareous endoskeletal spicule beginning at gastrulation. This process begins by ingression of prospective primary mesenchyme cells into the blastocoel, after which they migrate and then fuse to form a syncytium. Skeleton deposition occurs in spaces enclosed by the cytoplasmic cables between the cell bodies. Experiments are described which probe the role of proteases in these early events of spicule formation and their role in the continued elaboration of the spicule during later stages of embryogenesis. We find that several inhibitors of metalloproteinases inhibit the continuation of spiculogenesis, an effect first reported by Roe et al. (Exp. Cell Res. 181, 542-550, 1989). A detailed study of one of these inhibitors, BB-94, shows that fusion of primary mesenchyme cells still occurs in the presence of the inhibitor and the formation of the first calcite granule is not impeded. Continued elaboration of the spicule, however, is completely stopped; addition of the inhibitor during the active elongation of the spicule stops further elongation immediately. Removal of the inhibitor allows resumption of spicule growth. The inhibition is accompanied by almost complete cessation of massive Ca ion transport via the primary mesenchyme cells to the spicule. The inhibitor does not prevent the continued synthesis of several spicule matrix proteins. Electron microscopic examination of inhibited primary mesenchyme cells shows an accumulation of characteristic vesicles in the cytoplasm. Gel zymography demonstrates that although most proteases in homogenates of primary mesenchyme cells are not sensitive to the inhibitor in vitro, a protease of low abundance detectable in the medium of cultured primary mesenchyme cells is inhibited by BB-94. We propose that the inhibitor is interfering with the delivery of precipitated calcium carbonate and matrix proteins to the site(s) of spicule growth. Copyright 1998
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Bagley, Mark C.; Baashen, Mohammed; Chuckowree, Irina; Dwyer, Jessica E.; Kipling, David; Davis, Terence
2015-01-01
Microwave-assisted Suzuki-Miyaura cross-coupling reactions have been employed towards the synthesis of three different MAPKAPK2 (MK2) inhibitors to study accelerated aging in Werner syndrome (WS) cells, including the cross-coupling of a 2-chloroquinoline with a 3-pyridinylboronic acid, the coupling of an aryl bromide with an indolylboronic acid and the reaction of a 3-amino-4-bromopyrazole with 4-carbamoylphenylboronic acid. In all of these processes, the Suzuki-Miyaura reaction was fast and relatively efficient using a palladium catalyst under microwave irradiation. The process was incorporated into a rapid 3-step microwave-assisted method for the synthesis of a MK2 inhibitor involving 3-aminopyrazole formation, pyrazole C-4 bromination using N-bromosuccinimide (NBS), and Suzuki-Miyaura cross-coupling of the pyrazolyl bromide with 4-carbamoylphenylboronic acid to give the target 4-arylpyrazole in 35% overall yield, suitable for study in WS cells. PMID:26046488
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Bagley, Mark C; Baashen, Mohammed; Chuckowree, Irina; Dwyer, Jessica E; Kipling, David; Davis, Terence
2015-06-03
Microwave-assisted Suzuki-Miyaura cross-coupling reactions have been employed towards the synthesis of three different MAPKAPK2 (MK2) inhibitors to study accelerated aging in Werner syndrome (WS) cells, including the cross-coupling of a 2-chloroquinoline with a 3-pyridinylboronic acid, the coupling of an aryl bromide with an indolylboronic acid and the reaction of a 3-amino-4-bromopyrazole with 4-carbamoylphenylboronic acid. In all of these processes, the Suzuki-Miyaura reaction was fast and relatively efficient using a palladium catalyst under microwave irradiation. The process was incorporated into a rapid 3-step microwave-assisted method for the synthesis of a MK2 inhibitor involving 3-aminopyrazole formation, pyrazole C-4 bromination using N-bromosuccinimide (NBS), and Suzuki-Miyaura cross-coupling of the pyrazolyl bromide with 4-carbamoylphenylboronic acid to give the target 4-arylpyrazole in 35% overall yield, suitable for study in WS cells.
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Xu, Feng; Corley, Edward; Zacuto, Michael; Conlon, David A; Pipik, Brenda; Humphrey, Guy; Murry, Jerry; Tschaen, David
2010-03-05
A practical asymmetric synthesis of a novel aminopiperidine-fused imidazopyridine dipeptidyl peptidase IV (DPP-4) inhibitor 1 has been developed. Application of a unique three-component cascade coupling with chiral nitro diester 7, which is easily accessed via a highly enantioselective Michael addition of dimethyl malonate to a nitrostyrene, allows for the assembly of the functionalized piperidinone skeleton in one pot. Through a base-catalyzed, dynamic crystallization-driven process, the cis-piperidionone 16a is epimerized to the desired trans isomer 16b, which is directly crystallized from the crude reaction stream in high yield and purity. Isomerization of the allylamide 16b in the presence of RhCl(3) is achieved without any epimerization of the acid/base labile stereogenic center adjacent to the nitro group on the piperidinone ring, while the undesired enamine intermediate is consumed to <0.5% by utilizing a trace amount of HCl generated from RhCl(3). The amino lactam 4, obtained through hydrogenation and hydrolysis, is isolated as its crystalline pTSA salt from the reaction solution directly, as such intramolecular transamidation has been dramatically suppressed via kinetic control. Finally, a Cu(I) catalyzed coupling-cyclization allows for the formation of the tricyclic structure of the potent DPP-4 inhibitor 1. The synthesis, which is suitable for large scale preparation, is accomplished in 23% overall yield.
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Keller, Samantha M; Schreiber, William B; Stanfield, Briana R; Knox, Dayan
2015-01-01
Using the single prolonged stress (SPS) animal model of post-traumatic stress disorder (PTSD), previous studies suggest that enhanced glucocorticoid receptor (GR) expression leads to cued fear extinction retention deficits. However, it is unknown how the endogenous ligand of GRs, corticosterone (CORT), may contribute to extinction retention deficits in the SPS model. Given that CORT synthesis during fear learning is critical for fear memory consolidation and SPS enhances GR expression, CORT synthesis during fear memory formation could strengthen fear memory in SPS rats by enhancing GR activation during fear learning. In turn, this could lead to cued fear extinction retention deficits. We tested the hypothesis that CORT synthesis during fear learning leads to cued fear extinction retention deficits in SPS rats by administering the CORT synthesis inhibitor metyrapone to SPS and control rats prior to fear conditioning, and observed the effect this had on extinction memory. Inhibiting CORT synthesis during fear memory formation in control rats tended to decrease cued freezing, though this effect never reached statistical significance. Contrary to our hypothesis, inhibiting CORT synthesis during fear memory formation disrupted extinction retention in SPS rats. This finding suggests that even though SPS exposure leads to cued fear extinction memory deficits, CORT synthesis during fear memory formation enhances extinction retention in SPS rats. This suggests that stress-induced CORT synthesis in previously stressed rats can be beneficial. Copyright © 2015 Elsevier B.V. All rights reserved.
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Garbaccio, Robert M; Tasber, Edward S; Neilson, Lou Anne; Coleman, Paul J; Fraley, Mark E; Olson, Christy; Bergman, Jeff; Torrent, Maricel; Buser, Carolyn A; Rickert, Keith; Walsh, Eileen S; Hamilton, Kelly; Lobell, Robert B; Tao, Weikang; South, Vicki J; Diehl, Ronald E; Davide, Joseph P; Yan, Youwei; Kuo, Lawrence C; Li, Chunze; Prueksaritanont, Thomayant; Fernandez-Metzler, Carmen; Mahan, Elizabeth A; Slaughter, Donald E; Salata, Joseph J; Kohl, Nancy E; Huber, Hans E; Hartman, George D
2007-10-15
Observations from two structurally related series of KSP inhibitors led to the proposal and discovery of dihydropyrazolobenzoxazines that possess ideal properties for cancer drug development. The synthesis and characterization of this class of inhibitors along with relevant pharmacokinetic and in vivo data are presented. The synthesis is highlighted by a key [3+2] cycloaddition to form the pyrazolobenzoxazine core followed by diastereospecific installation of a quaternary center.
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NASA Astrophysics Data System (ADS)
Ahmed, Mohammed H. Othman; Al-Amiery, Ahmed A.; Al-Majedy, Yasmin K.; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar; Gaaz, Tayser Sumer
2018-03-01
The synthesis and characterization of a novel organic corrosion inhibitor (4-(3-mercapto-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazin-6-yl)phenol), for mild steel in 1 M hydrochloric acid (HCl) has been successfully reported for the first time. The inhibitor evaluated as corrosion inhibitor for mild steel in 1 M of Hydrochloric acid solution using electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) measurement techniques. Changes in the impedance parameters suggested an adsorption of the inhibitor onto the mild steel surface, leading to the formation of protective films. The results show that the inhibition efficiencies increased with increasing the concentrations of the inhibitors and decreased with increasing temperature. The maximum inhibition efficiency up to 67% at the maximum concentration 0.5 mM. This shows that those inhibitors are effective in helping to reduce and slowing down the corrosion process that occurs to mild steel with a hydrochloric acid solution by providing an organic inhibitor for the mild steel that can be weakened by increasing the temperature. The adsorption process of the synthesized organic inhibitor depends on its electronic characteristics in addition to steric effects and the nature of metal surface, temperature degree and the varying degrees of surface-site activity. The synthesized inhibitor molecules were absorbed by metal surface and follow Langmuir isotherms.
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Improved synthesis of ADAM10 inhibitor GI254023X.
Hoettecke, Nicole; Ludwig, Andreas; Foro, Sabine; Schmidt, Boris
2010-01-01
The metalloproteinases ADAM10 and ADAM17 are involved in various diseases: neurodegeneration, cancer and inflammation. The inhibition of these proteases is a promising target in the treatment of inflammation and cancer. In this study, we present an improved synthesis of the ADAM10 reference inhibitor GI254023X with a higher overall yield, enhanced detection ability and increased acid stability, providing easier handling. This upscaled synthesis, free of diastereomeric intermediates, ensures single-batch identity, thus warranting its reproducibility in further biological investigations. 2010 S. Karger AG, Basel.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Minor, P.D.; Dimmock, N.J.
1977-05-15
Various known inhibitors of cellular DNA function were shown to inhibit cellular RNA synthesis and influenza (fowl plague) virus multiplication. The drugs were investigated for their effect upon the synthesis of influenza virus proteins. According to this effect they could be classified with previously studied compounds as follows: Group I (ethidium bromide, proflavine, and N-nitroquinoline-N-oxide) inhibited both viral and cellular protein synthesis; Group II (nogalomycin, daunomycin and ..cap alpha..-amanitin) inhibited viral but not cellular protein synthesis, and all viral proteins were inhibited coordinately; Group III (mithramycin, echinomycin, and actinomycin D) inhibited all viral but not cellular protein synthesis at highmore » concentrations, but at a lower critical concentration inhibited the synthesis of viral haemagglutinin, neuraminidase, and M protein preferentially; Group IV(uv irradiation and camptothecin) inhibited the synthesis of viral haemagglutinin, neuraminidase, and M protein, but not other viral proteins, even at high doses. The mode of action of these inhibitors is discussed in relation to the mechanism of the nuclear events upon which influenza virus multiplication is dependent.« less
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A PHGDH inhibitor reveals coordination of serine synthesis and 1-carbon unit fate
Pacold, Michael E.; Brimacombe, Kyle R.; Chan, Sze Ham; Rohde, Jason M.; Lewis, Caroline A.; Swier, Lotteke J.Y.M.; Possemato, Richard; Chen, Walter W.; Sullivan, Lucas B.; Fiske, Brian P.; Cho, Sung Won; Freinkman, Elizaveta; Birsoy, Kıvanç; Abu-Remaileh, Monther; Shaul, Yoav D.; Liu, Chieh Min; Zhou, Minerva; Koh, Min Jung; Chung, Haeyoon; Davidson, Shawn M.; Luengo, Alba; Wang, Amy Q.; Xu, Xin; Yasgar, Adam; Liu, Li; Rai, Ganesha; Westover, Kenneth D.; Vander Heiden, Matthew G.; Shen, Min; Gray, Nathanael S.; Boxer, Matthew B.; Sabatini, David M.
2016-01-01
Serine is a both a proteinogenic amino acid and the source of one-carbon units essential for de novo purine and deoxythymidine synthesis. In the canonical glucose-derived serine synthesis pathway, Homo sapiens phosphoglycerate dehydrogenase (PHGDH) catalyzes the first, rate-limiting step. Genetic loss of PHGDH is toxic towards PHGDH-overexpressing breast cancer cell lines even in the presence of exogenous serine. Here, we use a quantitative high-throughput screen to identify small molecule PHGDH inhibitors. These compounds reduce the production of glucose-derived serine in cells and suppress the growth of PHGDH-dependent cancer cells in culture and in orthotopic xenograft tumors. Surprisingly, PHGDH inhibition reduced the incorporation into nucleotides of one-carbon units from glucose-derived and exogenous serine. We conclude that glycolytic serine synthesis coordinates the use of one-carbon units from endogenous and exogenous serine in nucleotide synthesis, and suggest that one-carbon unit wasting may contribute to the efficacy of PHGDH inhibitors in vitro and in vivo. PMID:27110680
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Dhar, T G Murali; Shen, Zhongqi; Fleener, Catherine A; Rouleau, Katherine A; Barrish, Joel C; Hollenbaugh, Diane L; Iwanowicz, Edwin J
2002-11-18
A modified approach to the synthesis of 3-(oxazolyl-5-yl) indoles is reported. This method was applied to the synthesis of series of novel indole based inhibitors of inosine monophosphate dehydrogenase (IMPDH). The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for this new series of inhibitors is given.
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Design, Synthesis, and Evaluation of New Tripeptides as COX-2 Inhibitors.
Vernieri, Ermelinda; Gomez-Monterrey, Isabel; Milite, Ciro; Grieco, Paolo; Musella, Simona; Bertamino, Alessia; Scognamiglio, Ilaria; Alcaro, Stefano; Artese, Anna; Ortuso, Francesco; Novellino, Ettore; Sala, Marina; Campiglia, Pietro
2013-01-01
Cyclooxygenase (COX) is a key enzyme in the biosynthetic pathway leading to the formation of prostaglandins, which are mediators of inflammation. It exists mainly in two isoforms COX-1 and COX-2. The conventional nonsteroidal anti-inflammatory drugs (NSAIDs) have gastrointestinal side effects because they inhibit both isoforms. Recent data demonstrate that the overexpression of these enzymes, and in particular of cyclooxygenases-2, promotes multiple events involved in tumorigenesis; in addition, numerous studies show that the inhibition of cyclooxygenases-2 can delay or prevent certain forms of cancer. Agents that inhibit COX-2 while sparing COX-1 represent a new attractive therapeutic development and offer a new perspective for a further use of COX-2 inhibitors. The present study extends the evaluation of the COX activity to all 20(3) possible natural tripeptide sequences following a rational approach consisting in molecular modeling, synthesis, and biological tests. Based on data obtained from virtual screening, only those peptides with better profile of affinity have been selected and classified into two groups called S and E. Our results suggest that these novel compounds may have potential as structural templates for the design and subsequent development of the new selective COX-2 inhibitors drugs.
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Arabinosylthymine: inhibitor of splenic lymphocyte macromolecular synthesis in vitro.
Barnett, J M; McGowan, J J; Gentry, G A
1979-01-01
The effect of arabinosylthymine on lymphocyte transformation was investigated. Arabinosylthymine was demonstrated not to be cytotoxic for hamster spleen lymphocytes but was found to inhibit the increase in deoxyribonucleic acid and protein synthesis usually observed as a result of mitogen stimulation. These findings suggest that, in addition to being a potent anti-herpesvirus inhibitor, arabinosylthymine is also an immunosuppressive agent. PMID:500206
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Metabolic approaches to enhance transdermal drug delivery. 1. Effect of lipid synthesis inhibitors.
Tsai, J C; Guy, R H; Thornfeldt, C R; Gao, W N; Feingold, K R; Elias, P M
1996-06-01
The intercellular domains of the stratum corneum, which contain a mixture of cholesterol, free fatty acids, and ceramides, mediate both the epidermal permeability barrier and the transdermal delivery of both lipophilic and hydrophilic molecules. Prior studies have shown that each of the three key lipid classes is required for normal barrier function. For example, selective inhibition of either cholesterol, fatty acid, or ceramide synthesis in the epidermis delays barrier recovery rates after barrier perturbation of hairless mouse skin in vivo. In this study, we investigated the potential of certain inhibitors of lipid synthesis to enhance the transdermal delivery of lidocaine or caffeine as a result of their capacity to perturb barrier homeostasis. After acetone disruption of the barrier, the extent of lidocaine delivery and the degree of altered barrier function paralleled each other. Moreover, the further alteration in barrier function produced by either the fatty acid synthesis inhibitor 5-(tetradecyloxy)-2-furancarboxylic acid (TOFA), the cholesterol synthesis inhibitor fluvastatin (FLU), or cholesterol sulfate (CS) resulted in a further increase in lidocaine absorption. Furthermore, coapplications of TOFA and CS together caused an additive increase in lidocaine uptake. Finally, a comparable increase in drug delivery occurred when the barrier was disrupted initially with DMSO instead of acetone; coapplications of TOFA and FLU together again delayed barrier recovery and increased drug delivery by about 8-fold vs delivery from a standard enhancing vehicle. Whereas these metabolic inhibitors also variably increased the octanol/water partitioning of the drugs studied (perhaps via complexion or pH alterations), physicochemical effects of the inhibitors alone did not alter drug uptake in intact skin; i.e., passive mechanisms alone cannot account for the net increase in drug delivery. Our results show that modulations of epidermal lipid biosynthesis, following
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Design and Synthesis of New Peptidomimetics as Potential Inhibitors of MurE.
Zivec, Matej; Turk, Samo; Blanot, Didier; Gobec, Stanislav
2011-03-01
With the continuing emergence and spread of multidrug-resistant bacteria, there is an urgent need for the development of new antimicrobial agents. One possible source of new antibacterial targets is the biosynthesis of the bacterial cell-wall peptidoglycan. The assembly of the peptide stem is carried out by four essential enzymes, known as the Mur ligases (MurC, D, E and F). We have designed and synthesised a focused library of compounds as potential inhibitors of UDP-N-acetylmuramoyl-L-alanyl-D-glutamate:L-lysine ligase (MurE) from Staphylococcus aureus. This was achieved using two approaches: (i) synthesis of transition-state analogues based on the methyleneamino core; and (ii) synthesis of MurE reaction product analogues. Two methyleneamino-based compounds are identified as initial hits for inhibitors of MurE.
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New peptide deformylase inhibitors design, synthesis and pharmacokinetic assessment.
Lv, Fengping; Chen, Chen; Tang, Yang; Wei, Jianhai; Zhu, Tong; Hu, Wenhao
2016-08-01
The docking approach for the screening of designed small molecule ligands, led to the identification of a critical arginine residue in peptide deformylase for spiro cyclopropyl PDF inhibitor's extra hydrophobic binding, providing us a useful tool for searching more efficient PDF inhibitors to fight for horrifying antibiotics resistance. Further synthetic modification was undertaken to optimize the potency of amide compounds. To lower metabolic susceptibility and in turn reduce unwanted metabolic toxicity that was observed clinically, while retaining desired antibacterial activity, the use of azoles as amide bioisosteres had also been investigated. After the completion of chemical synthesis, all the compounds were evaluated through in vitro antibacterial activity assay, some of which were further subject to in vivo rat pharmacokinetic assessment. Those findings in this letter showed that spiro cyclopropyl proline N-formyl hydroxylamines, and especially the bioisosteric azoles, can represent a promising class of PDF inhibitors. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Risk Factors for Inhibitor Formation in Hemophilia: A Prevalent Case-Control Study
Ragni, Margaret V.; Ojeifo, Oluseyi; Feng, Jinong; Yan, Jin; Hill, Kathleen A.; Sommer, Steve S.; Trucco, Massimo N.; Brambilla, Donald J.
2009-01-01
Background Inhibitor formation is a major complication of hemophilia treatment. Aim In a prevalent case-control study, we evaluated blood product exposure, genotype, and HLA type on hemophilia A inhibitor formation. Methods Product exposure was extracted from medical records. Genotype was determined on stored DNA samples by detection of virtually all mutations-SSCP (DOVAM-S) and subcycling PCR. HLA typing was performed by PCR amplification and exonuclease-released fluorescence. Results Cases experienced higher intensity factor, 455 vs. 200 U per exposure, p<0.005, more frequent central nervous system (CNS) bleeding, 7 of 20 (35.0%) vs. 1 of 57 (1.7%), p=0.001, and more commonly from inhibitor families, 7 of 20 (35.0%) vs. 0 of 57 (0%), p<0.001, and African-American, 12 of 63 (19.0%) vs. 6 of 117 (5.1%), p=0.015. Among the latter, CNS bleeding was more commonly the initial bleed, 60% vs. 0%, p<0.001, and survival was shorter, 14 vs. 38 yr, p=0.025. Inhibitor formation was uncommon in those with missense mutations, 2 of 65 (3.1%) vs. 31 of 119 (26.0%), p=0.008, and unrelated to factor VIII immunogenic epitope, p=0.388, or HLA type, p>0.100. Genotype was not associated with race. Time to immune tolerance was shorter for titers < 120 vs. ≥ 120 BU/ml, 6 vs. 16 months, p<0.01, but unaffected by tolerizing dose regimen, p>0.50. Conclusions Inhibitor formation is associated with high intensity product exposure, CNS bleeding, African-American race, and low frequency of missense mutations. The ideal time to initiate prophylaxis to reduce CNS bleeding and inhibitor formation will require prospective studies. PMID:19563499
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Dhar, T G Murali; Shen, Zhongqi; Gu, Henry H; Chen, Ping; Norris, Derek; Watterson, Scott H; Ballentine, Shelley K; Fleener, Catherine A; Rouleau, Katherine A; Barrish, Joel C; Townsend, Robert; Hollenbaugh, Diane L; Iwanowicz, Edwin J
2003-10-20
A series of novel small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH), based upon a 3-cyanoindole core, were explored. IMPDH catalyzes the rate determining step in guanine nucleotide biosynthesis and is a target for anticancer, immunosuppressive and antiviral therapy. The synthesis and the structure-activity relationships (SAR), derived from in vitro studies, for this new series of inhibitors is given.
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Wyatt, Emma E; Galloway, Warren R J D; Thomas, Gemma L; Welch, Martin; Loiseleur, Olivier; Plowright, Alleyn T; Spring, David R
2008-10-28
The screening of a diversity-oriented synthesis library followed by structure-activity relationship investigations have led to the discovery of an anti-MRSA agent which operates as an inhibitor of Staphylococcus aureus dihydrofolate reductase.
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Miki, Takashi; Kori, Masakuni; Mabuchi, Hiroshi; Tozawa, Ryu-ichi; Nishimoto, Tomoyuki; Sugiyama, Yasuo; Teshima, Koichiro; Yukimasa, Hidefumi
2002-09-26
Modification of the carboxyl group at the 3-position and introduction of protective groups to the hydroxy group of the 4,1-benzoxazepine derivative 2 (metabolite of 1) were carried out, and the inhibitory activity for squalene synthase and cholesterol synthesis in the liver was investigated. Among these compounds, the glycine derivative 3a and beta-alanine derivative 3f exhibited the most potent inhibition of squalene synthase prepared from HepG2 cells (IC(50) = 15 nM). On the other hand, the piperidine-4-acetic acid derivative 4a, which was prepared by acetylation of 3j, was the most effective inhibitor of cholesterol synthesis in rat liver (ED(50) = 2.9 mg/kg, po). After oral administration, 4a was absorbed and rapidly hydrolyzed to deacylated 3j. Compound 3j was detected mainly in the liver, but the plasma level of 3j was found to be low. Compounds 3j and 4a were found to be competitive inhibitors with respect to farnesyl pyrophosphate. Further evaluation of 4a as a cholesterol-lowering and antiatherosclerotic agent is underway.
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Gram-scale synthesis of the p38α MAPK-inhibitor VX-745 for preclinical studies into Werner syndrome.
Bagley, Mark C; Davis, Terence; Dix, Matthew C; Fusillo, Vincenzo; Pigeaux, Morgane; Rokicki, Michal J; Kipling, David
2010-09-01
The ATP-competitive p38α MAPK inhibitor VX-745 exhibits an exquisite kinase selectivity profile, is effective in blocking p38 stress signaling in Werner syndrome dermal fibroblasts, has efficacy in clinical trials and may have therapeutic value against Werner syndrome. Previous synthetic routes, however, have only resulted in milligram quantities suitable for cell-based studies, whereas gram quantities would be required for in vivo use. Microwave irradiation using a stop-flow monomodal microwave reactor has been found to facilitate scale-up of the synthesis of VX-745. Ullmann-type C-S bond formation using thiophenol, chloropyridazine, copper(I) catalyst and diol ligand proceeds rapidly and efficiently in this apparatus for elaboration to the pyrimido[1,6-b]pyridazinone core of VX-745 on gram scale and with good overall yield. This method delivers the p38 inhibitor VX-745 in sufficient quantities for preclinical studies to rescue the aging phenotype in Werner syndrome.
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Parsons, Joshua B.; Frank, Matthew W.; Subramanian, Chitra; Saenkham, Panatda; Rock, Charles O.
2011-01-01
The rationale for the pursuit of bacterial type 2 fatty acid synthesis (FASII) as a target for antibacterial drug discovery in Gram-positive organisms is being debated vigorously based on their ability to incorporate extracellular fatty acids. The regulation of FASII by extracellular fatty acids was examined in Staphylococcus aureus and Streptococcus pneumoniae, representing two important groups of pathogens. Both bacteria use the same enzymatic tool kit for the conversion of extracellular fatty acids to acyl-acyl carrier protein, elongation, and incorporation into phospholipids. Exogenous fatty acids completely replace the endogenous fatty acids in S. pneumoniae but support only 50% of phospholipid synthesis in S. aureus. Fatty acids overcame FASII inhibition in S. pneumoniae but not in S. aureus. Extracellular fatty acids strongly suppress malonyl-CoA levels in S. pneumoniae but not in S. aureus, showing a feedback regulatory system in S. pneumoniae that is absent in S. aureus. Fatty acids overcame either a biochemical or a genetic block at acetyl-CoA carboxylase (ACC) in S. aureus, confirming that regulation at the ACC step is the key difference between these two species. Bacteria that possess a stringent biochemical feedback inhibition of ACC and malonyl-CoA formation triggered by environmental fatty acids are able to circumvent FASII inhibition. However, if exogenous fatty acids do not suppress malonyl-CoA formation, FASII inhibitors remain effective in the presence of fatty acid supplements. PMID:21876172
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2012-01-01
A series of 36 thiosemicarbazone analogues containing the thiochromanone molecular scaffold functionalized primarily at the C-6 position were prepared by chemical synthesis and evaluated as inhibitors of cathepsins L and B. The most promising inhibitors from this group are selective for cathepsin L and demonstrate IC50 values in the low nanomolar range. In nearly all cases, the thiochromanone sulfide analogues show superior inhibition of cathepsin L as compared to their corresponding thiochromanone sulfone derivatives. Without exception, the compounds evaluated were inactive (IC50 > 10000 nM) against cathepsin B. The most potent inhibitor (IC50 = 46 nM) of cathepsin L proved to be the 6,7-difluoro analogue 4. This small library of compounds significantly expands the structure–activity relationship known for small molecule, nonpeptidic inhibitors of cathepsin L. PMID:24900494
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Evitt, Andrew S; Cox, Russell J
2011-05-01
Inhibitors of the enzyme aspartate semialdehyde dehydrogenase, a key biological target for the generation of a new class of antibiotic compounds, have been developed. To investigate improvements to binding within an inhibitor series, the lowering of the entropic barrier to binding through conformational restriction was investigated. A library of linear and cyclic substrate analogues was generated and computational docking used to aid in structure selection. The cyclic phosphonate inhibitor 18 was thus identified as complimentary to the enzyme active-site. Synthesis and in vitro inhibition assay revealed a K(i) of 3.8 mM against natural substrate, where the linear analogue of 18, compound 15, had previously shown no inhibitory activity. Two further inhibitors, phosphate analogue diastereoisomers 17a and 17b, were synthesised and also found to have low millimolar K(i) values. As a result of the computational docking investigations, a novel substrate binding interaction was discovered: hydrogen bonding between the substrate (phosphate hydroxy-group as the hydrogen bond donor) and the NADPH cofactor (2'-oxygen as the hydrogen bond acceptor).
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Discovery and gram-scale synthesis of BMS-593214, a potent, selective FVIIa inhibitor
DOE Office of Scientific and Technical Information (OSTI.GOV)
Priestley, E. Scott; De Lucca, Indawati; Zhou, Jinglan
A 6-amidinotetrahydroquinoline screening hit was driven to a structurally novel, potent, and selective FVIIa inhibitor through a combination of library synthesis and rational design. An efficient gram-scale synthesis of the active enantiomer BMS-593214 was developed, which required significant optimization of the key Povarov annulation. Importantly, BMS-593214 showed antithrombotic efficacy in a rabbit arterial thrombosis model. A crystal structure of BMS-593214 bound to FVIIa highlights key contacts with Asp 189, Lys 192, and the S2 pocket.
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Selective inhibitors of the osteoblast proteasome stimulate bone formation in vivo and in vitro
Garrett, I.R.; Chen, D.; Gutierrez, G.; Zhao, M.; Escobedo, A.; Rossini, G.; Harris, S.E.; Gallwitz, W.; Kim, K.B.; Hu, S.; Crews, C.M.; Mundy, G.R.
2003-01-01
We have found that the ubiquitin-proteasome pathway exerts exquisite control of osteoblast differentiation and bone formation in vitro and in vivo in rodents. Structurally different inhibitors that bind to specific catalytic β subunits of the 20S proteasome stimulated bone formation in bone organ cultures in concentrations as low as 10 nM. When administered systemically to mice, the proteasome inhibitors epoxomicin and proteasome inhibitor–1 increased bone volume and bone formation rates over 70% after only 5 days of treatment. Since the ubiquitin-proteasome pathway has been shown to modulate expression of the Drosophila homologue of the bone morphogenetic protein-2 and -4 (BMP-2 and BMP-4) genes, we examined the effects of noggin, an endogenous inhibitor of BMP-2 and BMP-4 on bone formation stimulated by these compounds and found that it was abrogated. These compounds increased BMP-2 but not BMP-4 or BMP-6 mRNA expression in osteoblastic cells, suggesting that BMP-2 was responsible for the observed bone formation that was inhibited by noggin. We show proteasome inhibitors regulate BMP-2 gene expression at least in part through inhibiting the proteolytic processing of Gli3 protein. Our results suggest that the ubiquitin-proteasome machinery regulates osteoblast differentiation and bone formation and that inhibition of specific components of this system may be useful therapeutically in common diseases of bone loss. PMID:12782679
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NASA Astrophysics Data System (ADS)
Frei, Reto
biofilm inhibitors and dispersers in the opportunistic pathogen Pseudomonas aeruginosa. Studies of second-generation 2-aminobenzimidazoles revealed important structure-activity relationships that guided the design of yet more potent analogs. These compounds are amongst the most potent inhibitors of biofilm formation in wild-type P. aeruginosa to be reported. Mechanistic studies of the most active compounds suggest that QS inhibition is one pathway by which 2-aminobenzimidazoles modulate biofilm growth.
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Kaminski, Rafal M.; Rogawski, Michael A.
2011-01-01
Steroid 11β-hydroxylase (CYP11B1; EC 1.14.15.4) is a mitochondrial enzyme located in the zona fasciculata of the adrenal cortex and also in the brain that mediates the conversion of 11-deoxycortisol to cortisol and 11-deoxycorticosterone (DOC) to corticosterone. Inhibitors of CYP11B1, such as metyrapone and etomidate, reduce glucocorticoid synthesis and raise levels of DOC providing greater availability for metabolic conversion to the GABAA receptor modulating neurosteroid allotetrahydrodeoxycorticosterone (THDOC). Because THDOC is a potent anticonvulsant, it is plausible that CYP11B1 inhibitors could protect against seizures. Here we demonstrate that metyrapone affords dose-dependent protection against 6-Hz seizures 30 min after injection (ED50, 191 mg/kg), but is markedly more potent at 6 h (ED50, 30 mg/kg). Similarly, etomidate is also protective at 30 min and 6 h (ED50 values, 4.5 and 1.7 mg/kg). Finasteride, an inhibitor of neurosteroid synthesis, attenuated the anticonvulsant effects of both CYP11B1 inhibitors at 6 h, but not 30 min following their injection. Plasma THDOC levels measured by liquid chromatography-mass spectrometry were markedly increased 6 h after injection of both CYP11B1 inhibitors and this increase was attenuated by finasteride pretreatment. We conclude that inhibition of CYP11B1 causes delayed seizure protection due to slow build-up of neurosteroids. Early seizure protection is independent of neurosteroids. PMID:21458468
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Bagley, Mark C; Dwyer, Jessica E; Molina, Maria D Beltran; Rand, Alexander W; Rand, Hayley L; Tomkinson, Nicholas C O
2015-06-28
Microwave irradiation of 2-halobenzonitriles and methyl thioglycolate in the presence of triethylamine in DMSO at 130 °C provides rapid access to 3-aminobenzo[b]thiophenes in 58-96% yield. This transformation has been applied in the synthesis of the thieno[2,3-b]pyridine core motif of LIMK1 inhibitors, the benzo[4,5]thieno[3,2-e][1,4]diazepin-5(2H)-one scaffold of MK2 inhibitors and a benzo[4,5]thieno[3,2-d]pyrimidin-4-one inhibitor of the PIM kinases.
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Structure-based Design and In-Parallel Synthesis of Inhibitors of AmpC b-lactamase
DOE Office of Scientific and Technical Information (OSTI.GOV)
Tondi, D.; Powers, R.A.; Negri, M.C.
2010-03-08
Group I {beta}-lactamases are a major cause of antibiotic resistance to {beta}-lactams such as penicillins and cephalosporins. These enzymes are only modestly affected by classic {beta}-lactam-based inhibitors, such as clavulanic acid. Conversely, small arylboronic acids inhibit these enzymes at sub-micromolar concentrations. Structural studies suggest these inhibitors bind to a well-defined cleft in the group I {beta}-lactamase AmpC; this cleft binds the ubiquitous R1 side chain of {beta}-lactams. Intriguingly, much of this cleft is left unoccupied by the small arylboronic acids. To investigate if larger boronic acids might take advantage of this cleft, structure-guided in-parallel synthesis was used to explore newmore » inhibitors of AmpC. Twenty-eight derivatives of the lead compound, 3-aminophenylboronic acid, led to an inhibitor with 80-fold better binding (2; K{sub i} 83 nM). Molecular docking suggested orientations for this compound in the R1 cleft. Based on the docking results, 12 derivatives of 2 were synthesized, leading to inhibitors with K{sub i} values of 60 nM and with improved solubility. Several of these inhibitors reversed the resistance of nosocomial Gram-positive bacteria, though they showed little activity against Gram-negative bacteria. The X-ray crystal structure of compound 2 in complex with AmpC was subsequently determined to 2.1 {angstrom} resolution. The placement of the proximal two-thirds of the inhibitor in the experimental structure corresponds with the docked structure, but a bond rotation leads to a distinctly different placement of the distal part of the inhibitor. In the experimental structure, the inhibitor interacts with conserved residues in the R1 cleft whose role in recognition has not been previously explored. Combining structure-based design with in-parallel synthesis allowed for the rapid exploration of inhibitor functionality in the R1 cleft of AmpC. The resulting inhibitors differ considerably from {beta}-lactams but
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Increased sensitivity to protein synthesis inhibitors in cells lacking tmRNA.
de la Cruz, J; Vioque, A
2001-01-01
tmRNA (also known as SsrA or 10Sa RNA) is involved in a trans-translation reaction that contributes to the recycling of stalled ribosomes at the 3' end of an mRNA lacking a stop codon or at an internal mRNA cluster of rare codons. Inactivation of the ssrA gene in most bacteria results in viable cells bearing subtle phenotypes, such as temperature-sensitive growth. Herein, we report on the functional characterization of the ssrA gene in the cyanobacterium Synechocystis sp. strain PCC6803. Deletion of the ssrA gene in Synechocystis resulted in viable cells with a growth rate identical to wild-type cells. However, null ssrA cells (deltassrA) were not viable in the presence of the protein synthesis inhibitors chloramphenicol, lincomycin, spiramycin, tylosin, erythromycin, and spectinomycin at low doses that do not significantly affect the growth of wild-type cells. Sensitivity of deltassrA cells similar to wild-type cells was observed with kasugamycin, fusidic acid, thiostrepton, and puromycin. Antibiotics unrelated to protein synthesis, such as ampicillin or rifampicin, had no differential effect on the deltassrA strain. Furthermore, deletion of the ssrA gene is sufficient to impair global protein synthesis when chloramphenicol is added at sublethal concentrations for the wild-type strain. These results indicate that ribosomes stalled by some protein synthesis inhibitors can be recycled by tmRNA. In addition, this suggests that the first elongation cycle with tmRNA, which incorporates a noncoded alanine on the growing peptide chain, may have mechanistic differences with the normal elongation cycles that bypasses the block produced by these specific antibiotics. tmRNA inactivation could be an useful therapeutic target to increase the sensitivity of pathogenic bacteria against antibiotics. PMID:11780628
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Direct modulation of T-box riboswitch-controlled transcription by protein synthesis inhibitors
Stamatopoulou, Vassiliki; Apostolidi, Maria; Li, Shuang; Lamprinou, Katerina; Papakyriakou, Athanasios
2017-01-01
Abstract Recently, it was discovered that exposure to mainstream antibiotics activate numerous bacterial riboregulators that control antibiotic resistance genes including metabolite-binding riboswitches and other transcription attenuators. However, the effects of commonly used antibiotics, many of which exhibit RNA-binding properties, on the widespread T-box riboswitches, remain unknown. In Staphylococcus aureus, a species-specific glyS T-box controls the supply of glycine for both ribosomal translation and cell wall synthesis, making it a promising target for next-generation antimicrobials. Here, we report that specific protein synthesis inhibitors could either significantly increase T-box-mediated transcription antitermination, while other compounds could suppress it, both in vitro and in vivo. In-line probing of the full-length T-box combined with molecular modelling and docking analyses suggest that the antibiotics that promote transcription antitermination stabilize the T-box:tRNA complex through binding specific positions on stem I and the Staphylococcal-specific stem Sa. By contrast, the antibiotics that attenuate T-box transcription bind to other positions on stem I and do not interact with stem Sa. Taken together, our results reveal that the transcription of essential genes controlled by T-box riboswitches can be directly modulated by commonly used protein synthesis inhibitors. These findings accentuate the regulatory complexities of bacterial response to antimicrobials that involve multiple riboregulators. PMID:28973457
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Karlström, Åsa; Boyd, Kelli L.; English, B. Keith; McCullers, Jonathan A.
2008-01-01
Pneumonia as a secondary infection after influenza is a major cause of excess morbidity and mortality despite the availability and use of antibiotics active against Streptococcus pneumoniae. We hypothesized that use of a bacteriostatic protein synthesis inhibitor would improve outcomes by reducing the inflammatory response. BALB/c mice infected with influenza virus and super-infected with Streptococcus pneumoniae were treated with either the cell wall active antibiotic ampicillin or protein synthesis inhibitors clindamycin or azithromycin. Ampicillin therapy performed significantly worse (56% survival) in the model compared to clindamycin therapy either alone (82%) or in combination with ampicillin (80%) and to azithromycin (92%). Improved survival appeared to be mediated by decreased inflammation manifested as lower levels of inflammatory cells and pro-inflammatory cytokines in the lungs, and less severe histopathology. These data suggest that beta-lactam therapy may not be optimal as first line treatment of community acquired pneumonia when it follows influenza. PMID:19113989
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NASA Astrophysics Data System (ADS)
Negmeldin, Ahmed Thabet
HDAC proteins have emerged as interesting targets for anti-cancer drugs due to their involvement in cancers, as well as several other diseases. Several HDAC inhibitors have been approved by the FDA as anti-cancer drugs, including SAHA (suberoylanilide hydroxamic acid, Vorinostat). Unfortunately, SAHA inhibits most HDAC isoforms, which limit its use as a pharmacological tool and may lead to side effects in the clinic. In this work we were interested in developing isoform selective HDAC inhibitors, which may decrease or eliminate the side effects associated with non-selective inhibitors treatment. In addition, isoform selective HDAC inhibitors can be used as biological tools to help understand the HDAC-related cancer biology. Our strategy was based on synthesis and screening of several derivatives of the non-selective FDA approved drug SAHA substituted at different positions of the linker region. Several SAHA analogs modified at the C4 and C5 positions of the linker were synthesized. The new C4- and C5-modified SAHA libraries, along with the previously synthesized C2-modified SAHA analogs were screened in vitro and in cellulo for HDAC isoform selectivity. Interestingly, several analogs exhibited dual HDAC6/HDAC8 selectivity. Enantioselective syntheses of the pure enantiomers of some of the interesting analogs were performed and the enantiomers were screened in vitro. Among the most interesting analogs, ( R)-C4-benzyl SAHA displayed 520- to 1300-fold selectivity for HDAC6 and HDAC8 over HDAC1, 2, and 3, with IC50 values of 48 and 27 nM with HDAC6 and 8, respectively. Docking studies were performed to provide structural rationale for the observed selectivity of the new analogs. In addition, rational design, synthesis, and screening of several other biaryl indolyl benzamide HDAC inhibitors is discussed, and some showed modest HDAC1 selectivity. The new biaryl indolyl benzamides can be useful to further develop HDAC1 selective inhibitors. The dual HDAC6/8 selective
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Design and synthesis of chalcone derivatives as potential non-purine xanthine oxidase inhibitors.
Bui, Trung Huu; Nguyen, Nhan Trung; Dang, Phu Hoang; Nguyen, Hai Xuan; Nguyen, Mai Thanh Thi
2016-01-01
Based on some previous research, the chalcone derivatives exhibited potent xanthine oxidase inhibitory activity, e.g. sappanchalcone ( 7 ), with IC 50 value of 3.9 μM, was isolated from Caesalpinia sappan . Therefore, objectives of this research are design and synthesis of 7 and other chalcone derivatives by Claisen-Schmidt condensation and then evaluate their XO inhibitory activity. Fifteen chalcone derivatives were synthesized by Claisen-Schmidt condensation, and were evaluated for XO inhibitory activity. Nine out of 15 synthetic chalcones showed inhibitory activity ( 3 ; 5 - 8 ; 10 - 13 ). Sappanchalcone derivatives ( 11 ) (IC 50 , 2.5 μM) and a novel chalcone ( 13 ) (IC 50 , 2.4 μM) displayed strong xanthine oxidase inhibitory activity that is comparable to allopurinol (IC 50 , 2.5 μM). The structure-activity relationship of these chalcone derivatives was also presented. It is the first research on synthesis sappanchalcone ( 7 ) by Claisen-Schmidt condensation. The overall yield of this procedure was 6.6 %, higher than that of reported procedure (4 %). Design, synthesis, and evaluation of chalcone derivatives were carried out. This result suggests that the chalcone derivative can be used as potential non-purine XO inhibitors.Graphical abstractThe chalcone derivatives as potential non-purine xanthine oxidase inhibitors.
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Synthesis and Characterization of Novel Acyl-Glycine Inhibitors of GlyT2.
Mostyn, Shannon N; Carland, Jane E; Shimmon, Susan; Ryan, Renae M; Rawling, Tristan; Vandenberg, Robert J
2017-09-20
It has been demonstrated previously that the endogenous compound N-arachidonyl-glycine inhibits the glycine transporter GlyT2, stimulates glycinergic neurotransmission, and provides analgesia in animal models of neuropathic and inflammatory pain. However, it is a relatively weak inhibitor with an IC 50 of 9 μM and is subject to oxidation via cyclooxygenase, limiting its therapeutic value. In this paper we describe the synthesis and testing of a novel series of monounsaturated C18 and C16 acyl-glycine molecules as inhibitors of the glycine transporter GlyT2. We demonstrate that they are up to 28 fold more potent that N-arachidonyl-glycine with no activity at the closely related GlyT1 transporter at concentrations up to 30 μM. This novel class of compounds show considerable promise as a first generation of GlyT2 transport inhibitors.
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Fyvie, W. Sean; Brindisi, Margherita; Steffey, Melinda; Agniswamy, Johnson; Wang, Yuan-Fang; Aoki, Manabu; Amano, Masayuki; Weber, Irene T.; Mitsuya, Hiroaki
2018-01-01
The structure-based design, synthesis, and biological evaluation of a series of nonpeptidic HIV-1 protease inhibitors with rationally designed P2′ ligands are described. The inhibitors are designed to enhance backbone binding interactions, particularly at the S2′ subsite. Synthesis of inhibitors was carried out efficiently. The stereochemistry of alcohol functionalities of the P2′ ligands was set by asymmetric reduction of the corresponding ketone using (R,R)- or (S,S)-Noyori catalysts. A number of inhibitors displayed very potent enzyme inhibitory and antiviral activity. Inhibitors 3g and 3h showed enzyme Ki values of 27.9 and 49.7 pM and antiviral activity of 6.2 and 3.9 nM, respectively. These inhibitors also remained quite potent against darunavir-resistant HIV-1 variants. An X-ray structure of inhibitor 3g in complex with HIV-1 protease revealed key interactions in the S2′ subsite. PMID:29110408
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Thromboxane synthesis inhibitors and postprandial jejunal capillary exchange capacity.
Mangino, M J; Chou, C C
1988-05-01
The effects of thromboxane synthesis inhibitors (imidazole and U 63557A; Upjohn) and the cyclooxygenase inhibitor, mefenamic acid, on jejunal capillary filtration coefficients (Kfc) were determined in dogs before and during the presence of predigested food in the jejunal lumen. The jejunal Kfc increased significantly soon after the placement of a predigested test food containing all major constituents of diet. The Kfc remained elevated as long as the food was present in the lumen (15 min). Mefenamic acid (10 mg/kg iv) did not significantly alter resting jejunal Kfc or alter the food-induced increase in Kfc. Imidazole (5.0 mg/min ia) or U 63557A (5.0 mg/kg iv) per se significantly increased jejunal Kfc. Placement of digested food further increased the Kfc to levels significantly higher than those observed before administration of the two thromboxane synthase inhibitors. Production of thromboxane B2 by jejunal tissue was significantly reduced and 6-ketoprostaglandin F1 alpha (the stable hydrolysis product of prostacyclin) production was significantly increased after administration of U 63557A. Our study indicates that the relative production of endogenous thromboxanes and other prostanoids modulates jejunal capillary exchange capacity in the absence or presence of digested food in the jejunal lumen.
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Murár, Miroslav; Addová, Gabriela
2013-01-01
Summary Background: 5-(Ethylsulfonyl)-2-methoxyaniline (5) is part of the structure in 131 compounds possessing different biological activities. In most cases, they have antitumor properties (112 compounds). Other compounds are described as cardiovascular agents, ion-channel blockers, nervous-system blockers, anti-inflammatory agents, or antidiabetic, antiosteoporotic and hypolipemic species. Compound 5 is a precursor of different protein-kinase inhibitors or enzyme modulators (EGFR, PDGFR, ckit, CDK 2 and 4, MMPs 2, 3, 9 and 13, etc.). The structure of 5 represents a fragment for several powerful inhibitors of VEGFR2, a key angiogenic receptor. Antiangiogenic inhibitors slow down or stop new blood-vessel formation from pre-existing vasculature. Some antiangiogenic drugs inhibiting the VEGFR2 receptor are successfully used in clinics for the treatment of several types of tumours in synergy with chemotherapy (e.g., Nexavar® from Bayer, Sutent® from Pfizer and Votrient® from GlaxoSmithKline, approved by the FDA in 2005, 2006 and 2009, respectively). The structure of 5 is an important pharmacophoric fragment of potent VEGFR2 inhibitors (e.g., AAZ from PDB complex 1Y6A, enzymatic IC50 = 22 nM). Up to now, 25 VEGFR2 inhibitors possessing a fragment of 5 can be found in the literature. Despite the high significance of 5-(ethylsulfonyl)-2-methoxyaniline (5) its preparation has not yet been described. Results: Here we have developed a convenient synthesis of important polyheterosubstituted aniline 5 starting from commercially available 4-methoxybenzene-1-sulfonyl chloride (1) in four steps and 59% overall yield. The target 5-(ethylsulfonyl)-2-methoxyaniline (5) and its synthetic intermediates 2–4 together with a new compound 5-(ethylsulfonyl)-2-methoxy-1,3-dinitrobenzene (4a) have been precisely physicochemically characterised. PMID:23399884
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Synthesis and evaluation of thiophenyl derivatives as inhibitors of alkaline phosphatase.
Chang, Lei; Duy, Do Le; Mébarek, Saida; Popowycz, Florence; Pellet-Rostaing, Stéphane; Lemaire, Marc; Buchet, René
2011-04-15
Pathological calcifications induced by deposition of basic phosphate crystals or hydroxyapatite (HA) on soft tissues are a large family of diseases comprising of ankylosing spondylitis (AS), end-stage osteoarthritis (OA) and vascular calcification. High activity of tissue non-specific alkaline phosphatase (TNAP) is a hallmark of pathological calcifications induced by HA deposition. The use of TNAP inhibitor is a possible therapeutic option to address calcific diseases produced by HA deposition on soft tissues. We report the synthesis of a series of thiopheno-imidazo[2,1-b]thiazole derivatives which were evaluated as potential inhibitors of TNAP displaying a large range of IC(50) at pH 10.4 (from 42±13 μM to more than 800 μM). Copyright © 2011. Published by Elsevier Ltd.
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Design and Synthesis of Novel Small-molecule Inhibitors of the Hypoxia Inducible Factor Pathway
Mooring, Suazette Reid; Jin, Hui; Devi, Narra S.; Jabbar, Adnan A.; Kaluz, Stefan; Liu, Yuan; Van Meir, Erwin G.; Wang, Binghe
2012-01-01
Hypoxia, a reduction in partial oxygen pressure, is a salient property of solid tumors. Hypoxia drives malignant progression and metastasis in tumors and participates in tumor resistance to radio- and chemotherapies. Hypoxia activates the hypoxia-inducible factor (HIF) family of transcription factors, which induce target genes that regulate adaptive biological processes such as anaerobic metabolism, cell motility and angiogenesis. Clinical evidence has demonstrated that expression of HIF-1 is strongly associated with poor patient prognosis and activation of HIF-1 contributes to malignant behavior and therapeutic resistance. Consequently, HIF-1 has become an important therapeutic target for inhibition by small molecules. Herein, we describe the design and synthesis of small molecules that inhibit the HIF-1 signaling pathway. Many of these compounds exhibit inhibitory activity in the nanomolar range. Separate mechanistic studies indicate that these inhibitors do not alter HIF-1 levels, but interfere with the HIF-1α/HIF-1β/p300/CBP complex formation by interacting with p300 and CBP. PMID:22032632
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Dow, Robert L; Andrews, Melissa; Aspnes, Gary E; Balan, Gayatri; Michael Gibbs, E; Guzman-Perez, Angel; Karki, Kapil; Laperle, Jennifer L; Li, Jian-Cheng; Litchfield, John; Munchhof, Michael J; Perreault, Christian; Patel, Leena
2011-10-15
A novel series of potent DGAT-1 inhibitors was developed originating from the lactam-based clinical candidate PF-04620110. Incorporation of a dioxino[2,3-d]pyrimidine-based core afforded good alignment of pharmacophore features and resulted in improved passive permeability. Development of an efficient, homochiral synthesis of these targets facilitated confirmation of predictions regarding the stereochemical-dependence of DGAT-1 inhibition for this series. Compound 10 was shown to be a potent inhibitor of human DGAT-1 (10 nM) and to suppress triglyceride synthesis at oral doses of <3mg/kg. Copyright © 2011 Elsevier Ltd. All rights reserved.
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Synthesis of Novel Compounds as New Potent Tyrosinase Inhibitors
Hamidian, Hooshang
2013-01-01
In the present paper, we report the synthesis and pharmacological evaluation of a new series of azo compounds with different groups (1-naphthol, 2-naphthol, and N,N-dimethylaniline) and trifluoromethoxy and fluoro substituents in the scaffold. All synthesized compounds (5a–5f) showed the most potent mushroom tyrosinase inhibition (IC50 values in the range of 4.39 ± 0.76–1.71 ± 0.49 µM), comparable to the kojic acid, as reference standard inhibitor. All the novel compounds were characterized by FT-IR, 1H NMR, 13C NMR, and elemental analysis. PMID:24260737
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Direct modulation of T-box riboswitch-controlled transcription by protein synthesis inhibitors.
Stamatopoulou, Vassiliki; Apostolidi, Maria; Li, Shuang; Lamprinou, Katerina; Papakyriakou, Athanasios; Zhang, Jinwei; Stathopoulos, Constantinos
2017-09-29
Recently, it was discovered that exposure to mainstream antibiotics activate numerous bacterial riboregulators that control antibiotic resistance genes including metabolite-binding riboswitches and other transcription attenuators. However, the effects of commonly used antibiotics, many of which exhibit RNA-binding properties, on the widespread T-box riboswitches, remain unknown. In Staphylococcus aureus, a species-specific glyS T-box controls the supply of glycine for both ribosomal translation and cell wall synthesis, making it a promising target for next-generation antimicrobials. Here, we report that specific protein synthesis inhibitors could either significantly increase T-box-mediated transcription antitermination, while other compounds could suppress it, both in vitro and in vivo. In-line probing of the full-length T-box combined with molecular modelling and docking analyses suggest that the antibiotics that promote transcription antitermination stabilize the T-box:tRNA complex through binding specific positions on stem I and the Staphylococcal-specific stem Sa. By contrast, the antibiotics that attenuate T-box transcription bind to other positions on stem I and do not interact with stem Sa. Taken together, our results reveal that the transcription of essential genes controlled by T-box riboswitches can be directly modulated by commonly used protein synthesis inhibitors. These findings accentuate the regulatory complexities of bacterial response to antimicrobials that involve multiple riboregulators. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.
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Synthesis of HIV-Maturation Inhibitor BMS-955176 from Betulin by an Enabling Oxidation Strategy.
Ortiz, Adrian; Soumeillant, Maxime; Savage, Scott A; Strotman, Neil A; Haley, Matthew; Benkovics, Tamas; Nye, Jeffrey; Xu, Zhongmin; Tan, Yichen; Ayers, Sloan; Gao, Qi; Kiau, Susanne
2017-05-05
A concise and scalable second generation synthesis of HIV maturation inhibitor BMS-955176 is described. The synthesis is framed by an oxidation strategy highlighted by a Cu I mediated aerobic oxidation of betulin, a highly selective PIFA mediated dehydrogenation of an oxime, and a subsequent Lossen rearrangement which occurs through a unique reaction mechanism for the installation of the C17 amino functionality. The synthetic route proceeds in 7 steps with 47% overall yield and begins from the abundant and inexpensive natural product betulin.
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Chiral-catalyst-based convergent synthesis of HIV protease inhibitor GRL-06579A.
Mihara, Hisashi; Sohtome, Yoshihiro; Matsunaga, Shigeki; Shibasaki, Masakatsu
2008-02-01
Catalytic asymmetric synthesis of GRL-06579A (1), an HIV-1 protease inhibitor effective against multi-protease-inhibitor-resistant viruses, is described. A convergent strategy that utilizes heterobimetallic multifunctional catalysts developed in our group is a key feature of the synthesis. The chirality of the bicyclic tetrahydrofuran unit of 1 was introduced through Al-Li-bis(binaphthoxide) (ALB) catalyst-controlled Michael addition of dimethyl malonate to racemic 4-O-protected cyclopentenone. ALB afforded not only the trans adduct with up to 96% ee from a matched substrate through kinetic resolution, but also the cis adduct with 99% ee through a catalyst-controlled Michael addition to a mismatched substrate. The Michael addition to produce the unusual cis adduct is described in detail. The framework of the bicyclic tetrahydrofuran was constructed by an intramolecular oxy-Michael reaction. The amino alcohol unit was constructed by an La-Li3-tris(binaphthoxide) (LLB)-catalyzed diastereoselective nitroaldol reaction of N-Boc aldehyde (Boc = tert-butoxycarbonyl) derived from L-phenylalanine. LLB promoted the nitroaldol reaction without racemization of the chiral aldehyde to give the nitroaldol adduct in 85% yield and with 93:7 diastereoselectivity and over 99% ee.
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Gerritz, Samuel W; Zhai, Weixu; Shi, Shuhao; Zhu, Shirong; Toyn, Jeremy H; Meredith, Jere E; Iben, Lawrence G; Burton, Catherine R; Albright, Charles F; Good, Andrew C; Tebben, Andrew J; Muckelbauer, Jodi K; Camac, Daniel M; Metzler, William; Cook, Lynda S; Padmanabha, Ramesh; Lentz, Kimberley A; Sofia, Michael J; Poss, Michael A; Macor, John E; Thompson, Lorin A
2012-11-08
This report describes the discovery and optimization of a BACE-1 inhibitor series containing an unusual acyl guanidine chemotype that was originally synthesized as part of a 6041-membered solid-phase library. The synthesis of multiple follow-up solid- and solution-phase libraries facilitated the optimization of the original micromolar hit into a single-digit nanomolar BACE-1 inhibitor in both radioligand binding and cell-based functional assay formats. The X-ray structure of representative inhibitors bound to BACE-1 revealed a number of key ligand:protein interactions, including a hydrogen bond between the side chain amide of flap residue Gln73 and the acyl guanidine carbonyl group, and a cation-π interaction between Arg235 and the isothiazole 4-methoxyphenyl substituent. Following subcutaneous administration in rats, an acyl guanidine inhibitor with single-digit nanomolar activity in cells afforded good plasma exposures and a dose-dependent reduction in plasma Aβ levels, but poor brain exposure was observed (likely due to Pgp-mediated efflux), and significant reductions in brain Aβ levels were not obtained.
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Vontzalidou, Argyro; Zoidis, Grigoris; Chaita, Eliza; Makropoulou, Maria; Aligiannis, Nektarios; Lambrinidis, George; Mikros, Emmanuel; Skaltsounis, Alexios-Leandros
2012-09-01
The synthesis, molecular modeling and biological evaluation of substituted deoxybenzoins and optimized dihydrostilbenes are reported. Preliminary structure-activity relationship data were elucidated and lead compounds suitable for further optimization were discovered. Dihydrostilbene 7 is a particularly potent inhibitor (IC(50)=8.44 μM, more potent than kojic acid). Copyright © 2012 Elsevier Ltd. All rights reserved.
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Synthetic (p)ppGpp Analogue Is an Inhibitor of Stringent Response in Mycobacteria
Syal, Kirtimaan; Flentie, Kelly; Bhardwaj, Neerupma; Maiti, Krishnagopal; Jayaraman, Narayanaswamy; Stallings, Christina L.
2017-01-01
ABSTRACT Bacteria elicit an adaptive response against hostile conditions such as starvation and other kinds of stresses. Their ability to survive such conditions depends, in part, on stringent response pathways. (p)ppGpp, considered to be the master regulator of the stringent response, is a novel target for inhibiting the survival of bacteria. In mycobacteria, the (p)ppGpp synthetase activity of bifunctional Rel is critical for stress response and persistence inside a host. Our aim was to design an inhibitor of (p)ppGpp synthesis, monitor its efficiency using enzyme kinetics, and assess its phenotypic effects in mycobacteria. As such, new sets of inhibitors targeting (p)ppGpp synthesis were synthesized and characterized by mass spectrometry and nuclear magnetic resonance spectroscopy. We observed significant inhibition of (p)ppGpp synthesis by RelMsm in the presence of designed inhibitors in a dose-dependent manner, which we further confirmed by monitoring the enzyme kinetics. The Rel enzyme inhibitor binding kinetics were investigated by isothermal titration calorimetry. Subsequently, the effects of the compounds on long-term persistence, biofilm formation, and biofilm disruption were assayed in Mycobacterium smegmatis, where inhibition in each case was observed. In vivo, (p)ppGpp levels were found to be downregulated in M. smegmatis treated with the synthetic inhibitors. The compounds reported here also inhibited biofilm formation by the pathogen Mycobacterium tuberculosis. The compounds were tested for toxicity by using an MTT assay with H460 cells and a hemolysis assay with human red blood cells, for which they were found to be nontoxic. The permeability of compounds across the cell membrane of human lung epithelial cells was also confirmed by mass spectrometry. PMID:28396544
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Sharp, Phillip P; Garnier, Jean-Marc; Hatfaludi, Tamas; Xu, Zhen; Segal, David; Jarman, Kate E; Jousset, Hélène; Garnham, Alexandra; Feutrill, John T; Cuzzupe, Anthony; Hall, Peter; Taylor, Scott; Walkley, Carl R; Tyler, Dean; Dawson, Mark A; Czabotar, Peter; Wilks, Andrew F; Glaser, Stefan; Huang, David C S; Burns, Christopher J
2017-12-14
A number of diazepines are known to inhibit bromo- and extra-terminal domain (BET) proteins. Their BET inhibitory activity derives from the fusion of an acetyl-lysine mimetic heterocycle onto the diazepine framework. Herein we describe a straightforward, modular synthesis of novel 1,2,3-triazolobenzodiazepines and show that the 1,2,3-triazole acts as an effective acetyl-lysine mimetic heterocycle. Structure-based optimization of this series of compounds led to the development of potent BET bromodomain inhibitors with excellent activity against leukemic cells, concomitant with a reduction in c- MYC expression. These novel benzodiazepines therefore represent a promising class of therapeutic BET inhibitors.
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Structure-Based Design and Synthesis of Potent and Selective Matrix Metalloproteinase 13 Inhibitors.
Choi, Jun Yong; Fuerst, Rita; Knapinska, Anna M; Taylor, Alexander B; Smith, Lyndsay; Cao, Xiaohang; Hart, P John; Fields, Gregg B; Roush, William R
2017-07-13
We describe the use of comparative structural analysis and structure-guided molecular design to develop potent and selective inhibitors (10d and (S)-17b) of matrix metalloproteinase 13 (MMP-13). We applied a three-step process, starting with a comparative analysis of the X-ray crystallographic structure of compound 5 in complex with MMP-13 with published structures of known MMP-13·inhibitor complexes followed by molecular design and synthesis of potent but nonselective zinc-chelating MMP inhibitors (e.g., 10a and 10b). After demonstrating that the pharmacophores of the chelating inhibitors (S)-10a, (R)-10a, and 10b were binding within the MMP-13 active site, the Zn 2+ chelating unit was replaced with nonchelating polar residues that bridged over the Zn 2+ binding site and reached into a solvent accessible area. After two rounds of structural optimization, these design approaches led to small molecule MMP-13 inhibitors 10d and (S)-17b, which bind within the substrate-binding site of MMP-13 and surround the catalytically active Zn 2+ ion without chelating to the metal. These compounds exhibit at least 500-fold selectivity versus other MMPs.
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Yu, Wen; Hallinen, Kelsey M.
2017-01-01
ABSTRACT Subinhibitory concentrations of antibiotics have been shown to enhance biofilm formation in multiple bacterial species. While antibiotic exposure has been associated with modulated expression of many biofilm-related genes, the mechanisms of drug-induced biofilm formation remain a focus of ongoing research efforts and may vary significantly across species. In this work, we investigate antibiotic-induced biofilm formation in Enterococcus faecalis, a leading cause of nosocomial infections. We show that biofilm formation is enhanced by subinhibitory concentrations of cell wall synthesis inhibitors but not by inhibitors of protein, DNA, folic acid, or RNA synthesis. Furthermore, enhanced biofilm is associated with increased cell lysis, increases in extracellular DNA (eDNA) levels, and increases in the density of living cells in the biofilm. In addition, we observe similar enhancement of biofilm formation when cells are treated with nonantibiotic surfactants that induce cell lysis. These findings suggest that antibiotic-induced biofilm formation is governed by a trade-off between drug toxicity and the beneficial effects of cell lysis. To understand this trade-off, we developed a simple mathematical model that predicts changes in antibiotic-induced biofilm formation due to external perturbations, and we verified these predictions experimentally. Specifically, we demonstrate that perturbations that reduce eDNA (DNase treatment) or decrease the number of living cells in the planktonic phase (a second antibiotic) decrease biofilm induction, while chemical inhibitors of cell lysis increase relative biofilm induction and shift the peak to higher antibiotic concentrations. Overall, our results offer experimental evidence linking cell wall synthesis inhibitors, cell lysis, increased eDNA levels, and biofilm formation in E. faecalis while also providing a predictive quantitative model that sheds light on the interplay between cell lysis and antibiotic efficacy in
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A role for autophagy in long-term spatial memory formation in male rodents.
Hylin, Michael J; Zhao, Jing; Tangavelou, Karthikeyan; Rozas, Natalia S; Hood, Kimberly N; MacGowan, Jacalyn S; Moore, Anthony N; Dash, Pramod K
2018-03-01
A hallmark of long-term memory formation is the requirement for protein synthesis. Administration of protein synthesis inhibitors impairs long-term memory formation without influencing short-term memory. Rapamycin is a specific inhibitor of target of rapamycin complex 1 (TORC1) that has been shown to block protein synthesis and impair long-term memory. In addition to regulating protein synthesis, TORC1 also phosphorylates Unc-51-like autophagy activating kinase-1 (Ulk-1) to suppress autophagy. As autophagy can be activated by rapamycin (and rapamycin inhibits long-term memory), our aim was to test the hypothesis that autophagy inhibitors would enhance long-term memory. To examine if learning alters autophagosome number, we used male reporter mice carrying the GFP-LC3 transgene. Using these mice, we observed that training in the Morris water maze task increases the number of autophagosomes, a finding contrary to our expectations. For learning and memory studies, male Long Evans rats were used due to their relatively larger size (compared to mice), making it easier to perform intrahippocampal infusions in awake, moving animals. When the autophagy inhibitors 3-methyladenine (3-MA) or Spautin-1 were administered bilaterally into the hippocampii prior to training in the Morris water maze task, the drugs did not alter learning. In contrast, when memory was tested 24 hours later by a probe trial, significant impairments were observed. In addition, intrahippocampal infusion of an autophagy activator peptide (TAT-Beclin-1) improved long-term memory. These results indicate that autophagy is not necessary for learning, but is required for long-term memory formation. © 2017 Wiley Periodicals, Inc.
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Design, Synthesis, and Evaluation of Novel Tyrosine-Based DNA Gyrase B Inhibitors.
Cotman, Andrej E; Trampuž, Marko; Brvar, Matjaž; Kikelj, Danijel; Ilaš, Janez; Peterlin-Mašič, Lucija; Montalvão, Sofia; Tammela, Päivi; Frlan, Rok
2017-08-01
The discovery and synthesis of new tyrosine-based inhibitors of DNA gyrase B (GyrB), which target its ATPase subunit, is reported. Twenty-four compounds were synthesized and evaluated for activity against DNA gyrase and DNA topoisomerase IV. The antibacterial properties of selected GyrB inhibitors were demonstrated by their activity against Staphylococcus aureus and Enterococcus faecalis in the low micromolar range. The most promising compounds, 8a and 13e, inhibited Escherichia coli and S. aureus GyrB with IC 50 values of 40 and 30 µM. The same compound also inhibited the growth of S. aureus and E. faecalis with minimal inhibitory concentrations (MIC 90 ) of 14 and 28 µg/mL, respectively. © 2017 Deutsche Pharmazeutische Gesellschaft.
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De, Surya K.; Chen, Vida; Stebbins, John L.; Chen, Li-Hsing; Cellitti, Jason F.; Machleidt, Thomas; Barile, Elisa; Riel-Mehan, Megan; Dahl, Russell; Yang, Li; Emdadi, Aras; Murphy, Ria; Pellecchia, Maurizio
2009-01-01
A series of thiadiazole derivatives has been designed as potential allosteric, substrate competitive inhibitors of the protein kinase JNK. We report on the synthesis, characterization and evaluation of a series of compounds that resulted in the identification of potent and selective JNK inhibitors targeting its JIP-1 docking site. PMID:20045647
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De Savi, Chris; Pape, Andrew; Cumming, John G; Ting, Attilla; Smith, Peter D; Burrows, Jeremy N; Mills, Mark; Davies, Chris; Lamont, Scott; Milne, David; Cook, Calum; Moore, Peter; Sawyer, Yvonne; Gerhardt, Stefan
2011-03-01
Two series of N-hydroxyformamide inhibitors of ADAM-TS4 were identified from screening compounds previously synthesised as inhibitors of matrix metalloproteinase-13 (collagenase-3). Understanding of the binding mode of this class of compound using ADAM-TS1 as a structural surrogate has led to the discovery of potent and very selective inhibitors with favourable DMPK properties. Synthesis, structure-activity relationships, and strategies to improve selectivity and lower in vivo metabolic clearance are described. Copyright © 2011 Elsevier Ltd. All rights reserved.
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ROLE OF NEUROTRANSMITTERS AND PROTEIN SYNTHESIS IN SHORT- AND LONG-TERM MEMORY
DOE Office of Scientific and Technical Information (OSTI.GOV)
Bennett, E.L.; Rosenzweig, M.R.; Flood, J.F.
1978-10-01
Anisomycin is an effective inhibitor of cerebral protein synthesis in mice and is also an effective amnestic agent for both passive and active behavioral tasks. From use of anisomycin in combination with a variety of stimulant and depressant drugs, we conclude that the level of arousal following acquisition plays an important role in determining the duration and the rate of the biosynthetic phase of memory formation. While we have interpreted the experiments with anisomycin as evidence for an essential role of protein in memory storage, others have suggested that side effects of inhibitors of protein synthesis on catecholamine metabolism aremore » the main cause of amnesia. Several experiments were therefore done to compare the effects of anisemycin and catecholamine inhibitors on memory. We conclude that anisomycin's principal amnestic mechanism does not involve inhibition of the catecholamine system. The results strengthen our conclusion that protein synthesis is an essential component for longterm memory trace formation. Also, it is suggested that proteins synthesized in the neuronal cell body are used, in conjunction with other molecules, to produce permanent and semi-permanent anatomical changes.« less
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Tran, Mai L; McCarthy, Thomas W; Sun, Hao; Wu, Shu-Zon; Norris, Joanna H; Bezanilla, Magdalena; Vidali, Luis; Anderson, Charles T; Roberts, Alison W
2018-01-15
Results from live cell imaging of fluorescently tagged Cellulose Synthase (CESA) proteins in Cellulose Synthesis Complexes (CSCs) have enhanced our understanding of cellulose biosynthesis, including the mechanisms of action of cellulose synthesis inhibitors. However, this method has been applied only in Arabidopsis thaliana and Brachypodium distachyon thus far. Results from freeze fracture electron microscopy of protonemal filaments of the moss Funaria hygrometrica indicate that a cellulose synthesis inhibitor, 2,6-dichlorobenzonitrile (DCB), fragments CSCs and clears them from the plasma membrane. This differs from Arabidopsis, in which DCB causes CSC accumulation in the plasma membrane and a different cellulose synthesis inhibitor, isoxaben, clears CSCs from the plasma membrane. In this study, live cell imaging of the moss Physcomitrella patens indicated that DCB and isoxaben have little effect on protonemal growth rates, and that only DCB causes tip rupture. Live cell imaging of mEGFP-PpCESA5 and mEGFP-PpCESA8 showed that DCB and isoxaben substantially reduced CSC movement, but had no measureable effect on CSC density in the plasma membrane. These results suggest that DCB and isoxaben have similar effects on CSC movement in P. patens and Arabidopsis, but have different effects on CSC intracellular trafficking, cell growth and cell integrity in these divergent plant lineages.
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The synthesis of a tritium, carbon-14, and stable isotope-labeled cathepsin C inhibitors.
Allen, Paul; Bragg, Ryan A; Caffrey, Moya; Ericsson, Cecilia; Hickey, Michael J; Kingston, Lee P; Elmore, Charles S
2017-02-01
As part of a medicinal chemistry program aimed at developing a highly potent and selective cathepsin C inhibitor, tritium, carbon-14, and stable isotope-labeled materials were required. The synthesis of tritium-labeled methanesulfonate 5 was achieved via catalytic tritiolysis of a chloro precursor, albeit at a low radiochemical purity of 67%. Tritium-labeled AZD5248 was prepared via a 3-stage synthesis, utilizing amide-directed hydrogen isotope exchange. Carbon-14 and stable isotope-labeled AZD5248 were successfully prepared through modifications of the medicinal chemistry synthetic route, enabling the use of available labeled intermediates. Copyright © 2016 John Wiley & Sons, Ltd.
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Hille, Ulrike E; Hu, Qingzhong; Vock, Carsten; Negri, Matthias; Bartels, Marc; Müller-Vieira, Ursula; Lauterbach, Thomas; Hartmann, Rolf W
2009-07-01
Recently, the steroidal CYP17 inhibitor Abiraterone entered phase II clinical trial for the treatment of androgen-dependent prostate cancer. As 17alpha-hydroxylase-17,20-lyase (CYP17) catalyzes the last step in androgen biosynthesis, inhibition of this target should affect not only testicular but also adrenal androgen formation. Therefore CYP17 inhibitors should be advantageous over existing therapies, for example with GnRH analogues. However, steroidal drugs are known for side effects which are due to affinities for steroid receptors. Therefore we decided to synthesize non-steroidal compounds mimicking the natural CYP17 substrates pregnenolone and progesterone. The synthesis and biological evaluation of a series of 15 novel and highly active non-steroidal CYP17 inhibitors are reported. The compounds were prepared via Suzuki-cross-coupling, Grignard reaction and CDI-assisted S(N)t-reaction with imidazole and their inhibitory activity was examined with recombinant human CYP17 expressed in Escherichia coli. Promising compounds were further tested for their selectivity against the hepatic enzyme CYP3A4 and the glucocorticoid-forming enzyme CYP11B1. All compounds turned out to be potent CYP17 inhibitors. The most active compounds 7 and 8 were much more active than Ketoconazole showing activity comparable to Abiraterone (IC(50) values of 90 and 52nM vs. 72nM). Most compounds also showed higher selectivities than Ketoconazole, but turned out to be less selective than Abiraterone. Docking studies using our CYP17 protein model were performed with selected compounds to study the interactions between the inhibitors and the amino acid residues of the active site.
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Enantioselective Synthesis and Profiling of Two Novel Diazabicyclooctanone β-Lactamase Inhibitors
2014-01-01
The enantioselective synthesis of two novel cyclopropane-fused diazabicyclooctanones is reported here. Starting from butadiene monoxide, the key enone intermediate 7 was prepared in six steps. Subsequent stereoselective introduction of the cyclopropane group and further transformation led to compounds 1a and 1b as their corresponding sodium salt. The great disparity regarding their hydrolytic stability was rationalized by the steric interaction between the cyclopropyl methylene and urea carbonyl. These two novel β-lactamase inhibitors were active against class A, C, and D enzymes. PMID:25313328
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Bukhari, S N A; Butt, A M; Amjad, M W B; Ahmad, W; Shah, V H; Trivedi, A R
2013-11-01
Hypertension is a widespread and frequently progressive ailment that imparts a foremost threat for cardiovascular and renal disorders. Mammoth efforts are needed for the synthesis of innovative antihypertensive agents to combat this lethal disease. Chalcones have shown antihypertensive activity through inhibition of Angiotensin Converting Enzyme (ACE). Hence, a series of chalcone analogues is synthesized and used as precursor for the synthesis of novel series of pyrimidines. Precursor chalcones were prepared by reacting aldehydes and ketones in presence of sodium hydroxide followed by synthesis of corresponding pyrimidines by reaction with urea in presence of potassium hydroxide. Both groups were then evaluated for their effects on ACE. The results depicted that pyrimidines were more active than chalcones with methoxy (C5 and P5) substitution showing best results to inhibit ACE. Given that chalcone analogues and pyrimidines show a potential as the angiotensin converting enzyme inhibitors.
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Zawadzke, Laura E; Norcia, Michael; Desbonnet, Charlene R; Wang, Hong; Freeman-Cook, Kevin; Dougherty, Thomas J
2008-02-01
The pathway for synthesis of the peptidoglycan precursor UDP-N-acetylmuramyl pentapeptide is essential in Gram-positive and Gram-negative bacteria. This pathway has been exploited in the recent past to identify potential new antibiotics as inhibitors of one or more of the Mur enzymes. In the present study, a high-throughput screen was employed to identify potential inhibitors of the Escherichia coli MurC (UDP-N-acetylmuramic acid:L-alanine ligase), the first of four paralogous amino acid-adding enzymes. Inhibition of ATP consumed during the MurC reaction, using an adaptation of a kinase assay format, identified a number of potential inhibitory chemotypes. After nonspecific inhibition testing and chemical attractiveness were assessed, C-1 emerged as a compound for further characterization. The inhibition of MurC by this compound was confirmed in both a kinetic-coupled enzyme assay and a direct nuclear magnetic resonance product detection assay. C-1 was found to be a low micromolar inhibitor of the E. coli MurC reaction, with preferential inhibition by one of two enantiomeric forms. Experiments indicated that it was a competitive inhibitor of ATP binding to the MurC enzyme. Further work with MurC enzymes from several bacterial sources revealed that while the compound was equally effective at inhibiting MurC from genera (Proteus mirabilis and Klebsiella pneumoniae) closely related to E. coli, MurC enzymes from more distant Gram-negative species such as Haemophilus influenzae, Acinetobacter baylyi, and Pseudomonas aeruginosa were not inhibited.
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Synthetic (p)ppGpp Analogue Is an Inhibitor of Stringent Response in Mycobacteria.
Syal, Kirtimaan; Flentie, Kelly; Bhardwaj, Neerupma; Maiti, Krishnagopal; Jayaraman, Narayanaswamy; Stallings, Christina L; Chatterji, Dipankar
2017-06-01
Bacteria elicit an adaptive response against hostile conditions such as starvation and other kinds of stresses. Their ability to survive such conditions depends, in part, on stringent response pathways. (p)ppGpp, considered to be the master regulator of the stringent response, is a novel target for inhibiting the survival of bacteria. In mycobacteria, the (p)ppGpp synthetase activity of bifunctional Rel is critical for stress response and persistence inside a host. Our aim was to design an inhibitor of (p)ppGpp synthesis, monitor its efficiency using enzyme kinetics, and assess its phenotypic effects in mycobacteria. As such, new sets of inhibitors targeting (p)ppGpp synthesis were synthesized and characterized by mass spectrometry and nuclear magnetic resonance spectroscopy. We observed significant inhibition of (p)ppGpp synthesis by Rel Msm in the presence of designed inhibitors in a dose-dependent manner, which we further confirmed by monitoring the enzyme kinetics. The Rel enzyme inhibitor binding kinetics were investigated by isothermal titration calorimetry. Subsequently, the effects of the compounds on long-term persistence, biofilm formation, and biofilm disruption were assayed in Mycobacterium smegmatis , where inhibition in each case was observed. In vivo , (p)ppGpp levels were found to be downregulated in M. smegmatis treated with the synthetic inhibitors. The compounds reported here also inhibited biofilm formation by the pathogen Mycobacterium tuberculosis The compounds were tested for toxicity by using an MTT assay with H460 cells and a hemolysis assay with human red blood cells, for which they were found to be nontoxic. The permeability of compounds across the cell membrane of human lung epithelial cells was also confirmed by mass spectrometry. Copyright © 2017 American Society for Microbiology.
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Frackowiak, Anna; Skibiński, Przemysław; Gaweł, Wiesław; Zaczyńska, Ewa; Czarny, Anna; Gancarz, Roman
2010-03-01
Synthesis of glycosyl derivatives of hydroxyanthraquinones (6-10) potentially useful for kidney stone therapy is presented. These compounds were analyzed as inhibitors of calcium oxalate crystals formation as well as substances with the ability of dissolving crystalline calcium oxalate. In addition, the effect of the compounds obtained on real kidney stones was analyzed by ex vivo tests. The tests on L929 and A545 cell lines have shown that the compounds obtained were not cytotoxic. Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.
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Dhar, T G Murali; Guo, Junqing; Shen, Zhongqi; Pitts, William J; Gu, Henry H; Chen, Bang-Chi; Zhao, Rulin; Bednarz, Mark S; Iwanowicz, Edwin J
2002-06-13
[structure: see text] A modified approach to the synthesis of 2-(N-aryl)-1,3-oxazoles, employing an optimized iminophosphorane/heterocumulene-mediated methodology, and its application to the synthesis of BMS-337197, a potent inhibitor of IMPDH, are described.
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Syal, Kirtimaan; Bhardwaj, Neerupma; Chatterji, Dipankar
2017-01-01
Earlier, vitamin C was demonstrated to sterilize Mycobacterium tuberculosis culture via Fenton's reaction at high concentration. It alters the regulatory pathways associated with stress response and dormancy. Since (p)ppGpp is considered to be the master regulator of stress response and is responsible for bacterial survival under stress, we tested the effect of vitamin C on the formation of (p)ppGpp. In vivo estimation of (p)ppGpp showed a decrease in (p)ppGpp levels in vitamin C-treated M. smegmatis cells in comparison to the untreated cells. Furthermore, in vitro (p)ppGpp synthesis using Rel MSM enzyme was conducted in order to confirm the specificity of the inhibition in the presence of variable concentrations of vitamin C. We observed that vitamin C at high concentration can inhibit the synthesis of (p)ppGpp. We illustrated binding of vitamin C to Rel MSM by isothermal titration calorimetry. Enzyme kinetics was followed where K 0.5 was found to be increased with the concomitant reduction of V max value suggesting mixed inhibition. Both long-term survival and biofilm formation were inhibited by vitamin C. The experiments suggest that vitamin C has the potential to be developed as the inhibitor of (p)ppGpp synthesis and stress response, at least in the concentration range used here. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
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Patterson, Stephen; Alphey, Magnus S; Jones, Deuan C; Shanks, Emma J; Street, Ian P; Frearson, Julie A; Wyatt, Paul G; Gilbert, Ian H; Fairlamb, Alan H
2011-10-13
Trypanothione reductase (TryR) is a genetically validated drug target in the parasite Trypanosoma brucei , the causative agent of human African trypanosomiasis. Here we report the discovery, synthesis, and development of a novel series of TryR inhibitors based on a 3,4-dihydroquinazoline scaffold. In addition, a high resolution crystal structure of TryR, alone and in complex with substrates and inhibitors from this series, is presented. This represents the first report of a high resolution complex between a noncovalent ligand and this enzyme. Structural studies revealed that upon ligand binding the enzyme undergoes a conformational change to create a new subpocket which is occupied by an aryl group on the ligand. Therefore, the inhibitor, in effect, creates its own small binding pocket within the otherwise large, solvent exposed active site. The TryR-ligand structure was subsequently used to guide the synthesis of inhibitors, including analogues that challenged the induced subpocket. This resulted in the development of inhibitors with improved potency against both TryR and T. brucei parasites in a whole cell assay.
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Konno, Hiroyuki; Wakabayashi, Masaki; Takanuma, Daiki; Saito, Yota; Akaji, Kenichi
2016-03-15
Synthesis of serine derivatives having the essential functional groups for the inhibitor of SARS 3CL protease and evaluation of their inhibitory activities using SARS 3CL R188I mutant protease are described. The lead compounds, functionalized serine derivatives, were designed based on the tetrapeptide aldehyde and Bai's cinnamoly inhibitor, and additionally performed with simulation on GOLD softwear. Structure activity relationship studies of the candidate compounds were given reasonable inhibitors ent-3 and ent-7k against SARS 3CL R188I mutant protease. These inhibitors showed protease selectivity and no cytotoxicity. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Blass, Benjamin E; Iyer, Pravin; Abou-Gharbia, Magid; Childers, Wayne E; Gordon, John C; Ramanjulu, Mercy; Morton, George; Arumugam, Premkumar; Boruwa, Joshodeep; Ellingboe, John; Mitra, Sayan; Reddy Nimmareddy, Rajashekar; Paliwal, Shalini; Rajasekhar, Jamallamudi; Shivakumar, Savithiri; Srivastava, Pratima; Tangirala, Raghuram S; Venkataramanaiah, Konda; Bobbala, Ramreddy; Yanamandra, Mahesh; Krishnakanth Reddy, L
2018-07-15
The synthesis of steroid hormones is critical to human physiology and improper regulation of either the synthesis of these key molecules or activation of the associated receptors can lead to disease states. This has led to intense interest in developing compounds capable of modulating the synthesis of steroid hormones. Compounds capable of inhibiting Cyp19 (Aromatase), a key enzyme in the synthesis of estrogens, have been successfully employed as breast cancer therapies, while inhibitors of Cyp17 (17α-hydroxylase-17,20-lyase), a key enzyme in the synthesis of glucocorticoids, mineralocorticoids and steroidal sex hormones, are a key component of prostate cancer therapy. Inhibition of CYP17 has also been suggested as a possible target for the treatment of Cushing Syndrome and Metabolic Syndrome. We have identified two novel series of stilbene based CYP17 inhibitors and demonstrated that exemplary compounds in these series have pharmacokinetic properties consistent with orally delivered drugs. These findings suggest that compounds in these classes may be useful for the treatment of diseases and conditions associated with improper regulation of glucocorticoids synthesis and glucocorticoids receptor activation. Copyright © 2018. Published by Elsevier Ltd.
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Beyer, Lydia; Doberenz, Claudia; Falke, Dörte; Hunger, Doreen; Suppmann, Bernhard
2013-01-01
Enterobacteria such as Escherichia coli generate formate, lactate, acetate, and succinate as major acidic fermentation products. Accumulation of these products in the cytoplasm would lead to uncoupling of the membrane potential, and therefore they must be either metabolized rapidly or exported from the cell. E. coli has three membrane-localized formate dehydrogenases (FDHs) that oxidize formate. Two of these have their respective active sites facing the periplasm, and the other is in the cytoplasm. The bidirectional FocA channel translocates formate across the membrane delivering substrate to these FDHs. FocA synthesis is tightly coupled to synthesis of pyruvate formate-lyase (PflB), which generates formate. In this study, we analyze the consequences on the fermentation product spectrum of altering FocA levels, uncoupling FocA from PflB synthesis or blocking formate metabolism. Changing the focA translation initiation codon from GUG to AUG resulted in a 20-fold increase in FocA during fermentation and an ∼3-fold increase in PflB. Nevertheless, the fermentation product spectrum throughout the growth phase remained similar to that of the wild type. Formate, acetate, and succinate were exported, but only formate was reimported by these cells. Lactate accumulated in the growth medium only in mutants lacking FocA, despite retaining active PflB, or when formate could not be metabolized intracellularly. Together, these results indicate that FocA has a strong preference for formate as a substrate in vivo and not other acidic fermentation products. The tight coupling between FocA and PflB synthesis ensures adequate substrate delivery to the appropriate FDH. PMID:23335413
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Yang, Bin; Lamb, Michelle L; Zhang, Tao; Hennessy, Edward J; Grewal, Gurmit; Sha, Li; Zambrowski, Mark; Block, Michael H; Dowling, James E; Su, Nancy; Wu, Jiaquan; Deegan, Tracy; Mikule, Keith; Wang, Wenxian; Kaspera, Rüdiger; Chuaqui, Claudio; Chen, Huawei
2014-12-11
KIFC1 (HSET), a member of the kinesin-14 family of motor proteins, plays an essential role in centrosomal bundling in cancer cells, but its function is not required for normal diploid cell division. To explore the potential of KIFC1 as a therapeutic target for human cancers, a series of potent KIFC1 inhibitors featuring a phenylalanine scaffold was developed from hits identified through high-throughput screening (HTS). Optimization of the initial hits combined both design-synthesis-test cycles and an integrated high-throughput synthesis and biochemical screening method. An important aspect of this integrated method was the utilization of DMSO stock solutions of compounds registered in the corporate compound collection as synthetic reactants. Using this method, over 1500 compounds selected for structural diversity were quickly assembled in assay-ready 384-well plates and were directly tested after the necessary dilutions. Our efforts led to the discovery of a potent KIFC1 inhibitor, AZ82, which demonstrated the desired centrosome declustering mode of action in cell studies.
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Sagar, Sneha R; Agarwal, Jessica K; Pandya, Dhaivat H; Dash, Ranjeet Prasad; Nivsarkar, Manish; Vasu, Kamala K
2015-10-15
We report the design, synthesis, biological activity and docking studies of series of novel pyrazolo[3,4-d]pyrimidinones as DPP-IV inhibitors in diabetes. Molecules were synthesized and evaluated for their DPP-IV inhibition activity. Compounds 5e, 5k, 5o and 6a were found to be potent inhibitors of DPP-IV enzyme. Amongst all the synthesized compounds, 6-methyl-5-(4-methylpyridin-2-yl)-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one (5k) was found to be the most active based on in vitro DPP-IV studies and also exhibited promising in vivo blood glucose lowering activity in male Wistar rats. Copyright © 2015. Published by Elsevier Ltd.
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Rashid, Davood; Panda, B P; Vohora, Divya
2015-11-01
Neurosteroids, such as testosterone and their metabolites, are known to modulate neuronal excitability. The enzymes regulating the metabolism of these neurosteroids, thus, may be targeted as a noval strategy for the development of new antiepileptic drugs. The present work targeted two such enzymes i,e aromatase and 5α-reductase in order to explore the potential of letrozole (an aromatase inhibitor) on pentylenetetrazole (PTZ)-induced kindling in mice and the ability of finasteride (a 5α-reductase inhibitor) to modulate any such effects. PTZ (30 mg/kg, i.p.), when administered once every two days (for a total of 24 doses) induced kindling in Swiss albino mice. Letrozole (1 mg/kg, p.o.), administered prior to PTZ, significantly reduced the % incidence of kindling, delayed mean onset time of seizures and reduced seizure severity score. Letrozole reduced the levels of plasma 17β-estradiol after induction of kindling. The concurrent administration of finasteride and letrozole produced effects similar to letrozole on PTZ-kindling and on estradiol levels. This implies that the ability of letrozole to redirect the synthesis of dihydrotestosterone (DHT) and 5α-androstanediol from testosterone doesn't appear to play a significant role in the protective effects of letrozole against PTZ kindling. Letrozole, however, increased the levels of 5α-DHT in mice plasma. The aromatase inhibitors, thus, may be exploited for inhibiting the synthesis of proconvulsant (17β-estradiol) and/or redirecting the synthesis of anticonvulsant (DHT and 5α-androstanediol) neurosteroids. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Scheppokat, Angela M; Gerber, Agnes; Schroven, Andreas; Meinke, Sebastian; Kopitzki, Sebastian; Beketow, Eugen; Thimm, Julian; Thiem, Joachim
2010-01-01
Glycosyltransferases from the albumen gland of Helix pomatia could be used in tandem mode for the chemoenzymatic synthesis of beta,1-3/beta,1-6-linked oligogalactans. By employing recombinant trans-sialidase of Trypanosoma cruzi (TcTS) the formation of a range of modified Galbeta,1-3GalNAc derivatives could be terminally alpha,2-3 sialylated. Biacore studies indicated the binding of these modified trisaccharides to myelin-associated glycoprotein (MAG). Using an eight-step synthetic route N-acyl-modified sialyl donor structures could be obtained. TcTS was used to transfer these structures to an isolactoside, and Michaelis constants of the donors indicated the kind and size of modifications allowed at the 5-nitrogen site. A number of sialic acid C-glycosides could be obtained via the C-allyl sialoside and subsequent metathesis. Biacore measurements showed derivatives substituted with aromatic residues to give K(D) values in the mM range. Benzaldehyde-functionalized glycosides of mono and disaccharides were synthesized by metathesis and could be used for the formation of novel glyco-self assembled monolayers (glyco-SAMs) employing various tether structures and attached to gold surfaces. Initial experiments were performed with concanavalin A and manno-SAMs. By atomic force microscopic measurements of tethered glycosides attached to gold-coated tips and surfaces weak forces in the nN range could be detected. Structure activity correlation of forces suggested rationales for complex interactions of various glycosides including minor stereochemical variations. Copyright (c) 2009 Elsevier GmbH. All rights reserved.
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Acetobixan, an Inhibitor of Cellulose Synthesis Identified by Microbial Bioprospecting
Xia, Ye; Lei, Lei; Brabham, Chad; Stork, Jozsef; Strickland, James; Ladak, Adam; Gu, Ying; Wallace, Ian; DeBolt, Seth
2014-01-01
In plants, cellulose biosynthesis is an essential process for anisotropic growth and therefore is an ideal target for inhibition. Based on the documented utility of small-molecule inhibitors to dissect complex cellular processes we identified a cellulose biosynthesis inhibitor (CBI), named acetobixan, by bio-prospecting among compounds secreted by endophytic microorganisms. Acetobixan was identified using a drug-gene interaction screen to sift through hundreds of endophytic microbial secretions for one that caused synergistic reduction in root expansion of the leaky AtcesA6prc1-1 mutant. We then mined this microbial secretion for compounds that were differentially abundant compared with Bacilli that failed to mimic CBI action to isolate a lead pharmacophore. Analogs of this lead compound were screened for CBI activity, and the most potent analog was named acetobixan. In living Arabidopsis cells visualized by confocal microscopy, acetobixan treatment caused CESA particles localized at the plasma membrane (PM) to rapidly re-localize to cytoplasmic vesicles. Acetobixan inhibited 14C-Glc uptake into crystalline cellulose. Moreover, cortical microtubule dynamics were not disrupted by acetobixan, suggesting specific activity towards cellulose synthesis. Previous CBI resistant mutants such as ixr1-2, ixr2-1 or aegeus were not cross resistant to acetobixan indicating that acetobixan targets a different aspect of cellulose biosynthesis. PMID:24748166
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Grolla, Ambra A; Podestà, Valeria; Chini, Maria Giovanna; Di Micco, Simone; Vallario, Antonella; Genazzani, Armando A; Canonico, Pier Luigi; Bifulco, Giuseppe; Tron, Gian Cesare; Sorba, Giovanni; Pirali, Tracey
2009-05-14
HDAC inhibitors show great promise for the treatment of cancer. As part of a broader effort to explore the SAR of HDAC inhibitors, synthesis, biological evaluation, and molecular docking of novel Ugi products containing a zinc-chelating moiety are presented. One compound shows improved inhibitory potencies compared to SAHA, demonstrating that hindered lipophilic residues grafted on the peptide scaffold of the alpha-aminoacylamides can be favorable in the interaction with the enzyme.
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Inhibitors Selective for Mycobacterial Versus Human Proteasomes
DOE Office of Scientific and Technical Information (OSTI.GOV)
Lin, G.; Li, D; Sorio de Carvalho, L
Many anti-infectives inhibit the synthesis of bacterial proteins, but none selectively inhibits their degradation. Most anti-infectives kill replicating pathogens, but few preferentially kill pathogens that have been forced into a non-replicating state by conditions in the host. To explore these alternative approaches we sought selective inhibitors of the proteasome of Mycobacterium tuberculosis. Given that the proteasome structure is extensively conserved, it is not surprising that inhibitors of all chemical classes tested have blocked both eukaryotic and prokaryotic proteasomes, and no inhibitor has proved substantially more potent on proteasomes of pathogens than of their hosts. Here we show that certain oxathiazol-2-onemore » compounds kill non-replicating M.?tuberculosis and act as selective suicide-substrate inhibitors of the M.?tuberculosis proteasome by cyclocarbonylating its active site threonine. Major conformational changes protect the inhibitor-enzyme intermediate from hydrolysis, allowing formation of an oxazolidin-2-one and preventing regeneration of active protease. Residues outside the active site whose hydrogen bonds stabilize the critical loop before and after it moves are extensively non-conserved. This may account for the ability of oxathiazol-2-one compounds to inhibit the mycobacterial proteasome potently and irreversibly while largely sparing the human homologue.« less
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An inhibitor of eIF2 activity in the sRNA pool of eukaryotic cells.
Centrella, Michael; Porter, David L; McCarthy, Thomas L
2011-08-15
Eukaryotic protein synthesis is a multi-step and highly controlled process that includes an early initiation complex containing eukaryotic initiation factor 2 (eIF2), GTP, and methionine-charged initiator methionyl-tRNA (met-tRNAi). During studies to reconstruct formation of the ternary complex containing these molecules, we detected a potent inhibitor in low molecular mass RNA (sRNA) preparations of eukaryotic tRNA. The ternary complex inhibitor (TCI) was retained in the total sRNA pool after met-tRNAi was charged by aminoacyl tRNA synthetase, co-eluted with sRNA by size exclusion chromatography, but resolved from met-tRNAi by ion exchange chromatography. The adverse effect of TCI was not overcome by high GTP or magnesium omission and was independent of GTP regeneration. Rather, TCI suppressed the rate of ternary complex formation, and disrupted protein synthesis and the accumulation of heavy polymeric ribosomes in reticulocyte lysates in vitro. Lastly, a component or components in ribosome depleted cell lysate significantly reversed TCI activity. Since assembly of the met-tRNAi/eIF2/GTP ternary complex is integral to protein synthesis, awareness of TCI is important to avoid confusion in studies of translation initiation. A clear definition of TCI may also allow a better appreciation of physiologic or pathologic situations, factors, and events that control protein synthesis in vivo. Copyright © 2011 Elsevier B.V. All rights reserved.
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Saeed, Aamer; Mahesar, Parvez Ali; Zaib, Sumera; Khan, Muhammad Siraj; Matin, Abdul; Shahid, Mohammad; Iqbal, Jamshed
2014-05-06
The present study reports the synthesis of cinnamide derivatives and their biological activity as inhibitors of both cholinesterases and anticancer agents. Controlled inhibition of brain acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) may slow neurodegeneration in Alzheimer's diseases (AD). The anticholinesterase activity of phenylcinnamide derivatives was determined against Electric Eel acetylcholinesterase (EeAChE) and horse serum butyrylcholinesterase (hBChE) and some of the compounds appeared as moderately potent inhibitors of EeAChE and hBChE. The compound 3-(2-(Benzyloxy)phenyl)-N-(3,4,5-trimethoxyphenyl)acrylamide (3i) showed maximum activity against EeAChE with an IC50 0.29 ± 0.21 μM whereas 3-(2-chloro-6-nitrophenyl)-N-(3,4,5-trimethoxyphenyl)acrylamide (3k) was proved to be the most potent inhibitor of hBChE having IC50 1.18 ± 1.31 μM. To better understand the enzyme-inhibitor interaction of the most active compounds toward cholinesterases, molecular modelling studies were carried out on high-resolution crystallographic structures. The anticancer effects of synthesized compounds were also evaluated against cancer cell line (lung carcinoma). The compounds may be useful leads for the design of a new class of anticancer drugs for the treatment of cancer and cholinesterase inhibitors for Alzheimer's disease (AD). Copyright © 2014 Elsevier Masson SAS. All rights reserved.
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Target-induced formation of neuraminidase inhibitors from in vitro virtual combinatorial libraries
Hochgürtel, Matthias; Kroth, Heiko; Piecha, Dorothea; Hofmann, Michael W.; Nicolau, Claude; Krause, Sonja; Schaaf, Otmar; Sonnenmoser, Gabriele; Eliseev, Alexey V.
2002-01-01
Neuraminidase, a key enzyme responsible for influenza virus propagation, has been used as a template for selective synthesis of small subsets of its own inhibitors from theoretically highly diverse dynamic combinatorial libraries. We show that the library building blocks, aldehydes and amines, form significant amounts of the library components resulting from their coupling by reductive amination only in the presence of the enzyme. The target amplifies the best hits at least 120-fold. The dynamic libraries synthesized and screened in such an in vitro virtual mode form the components that possess high inhibitory activity, as confirmed by enzyme assays with independently synthesized individual compounds. PMID:11891312
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Peters, Godefridus J
2018-05-03
The pyrimidine de novo nucleotide synthesis consists of 6 sequential steps. Various inhibitors against these enzymes have been developed and evaluated in the clinic for their potential anticancer activity: acivicin inhibits carbamoyl-phosphate-synthase-II, N-(phosphonacetyl)-L- aspartate (PALA) inhibits aspartate-transcarbamylase, Brequinar sodium and dichloroallyl-lawsone (DCL) inhibit dihydroorotate-dehydrogenase, and pyrazofurin (PF) inhibits orotate-phosphoribosyltransferase. We compared their growth inhibition against 3 cell lines from head-and-neck-cancer (HEP-2, UMSCC-14B and UMSCC-14C) and related the sensitivity to their effects on nucleotide pools. In all cell lines Brequinar and PF were the most active compounds with IC50 (50% growth inhibition) values between 0.06-0.37 µM, Acivicin was as potent (IC50s 0.26-1 µM), but DCL was 20-31-fold less active. PALA was most inactive (24-128 µM). At equitoxic concentrations, all pure antipyrimidine de novo inhibitors depleted UTP and CTP after 24 hr exposure, which was most pronounced for Brequinar (between 6-10% of UTP left, and 12-36% CTP), followed by DCL and PF, which were almost similar (6-16% UTP and 12-27% CTP), while PALA was the least active compound (10-70% UTP and 13-68% CTP). Acivicin is a multi-target inhibitor of more glutamine requiring enzymes (including GMP synthetase) and no decrease of UTP was found, but a pronounced decrease in GTP (31-72% left). In conclusion, these 5 inhibitors of the pyrimidine de novo nucleotide synthesis varied considerably in their efficacy and effect on pyrimidine nucleotide pools. Inhibitors of DHO-DH were most effective suggesting a primary role of this enzyme in controlling pyrimidine nucleotide pools.
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Efficient Synthesis and Discovery of Schiff Bases as Potent Cholinesterase Inhibitors.
Razik, Basma M Abd; Osman, Hasnah; Ezzat, Mohammed O; Basiri, Alireza; Salhin, Abdussalam; Kia, Yalda; Murugaiyah, Vikneswaran
2016-01-01
The search for new cholinesterase inhibitors is still a promising approach for management of Alzheimer`s disease. Schiff bases are considered as important class of organic compounds, which have wide range of applications including as enzyme inhibitors. In the present study, a new green ionic liquid mediated strategy was developed for convenient synthesis of two series of Schiff bases 3(a-j) and 5(a-j) as potential cholinesterase inhibitors using aromatic aldehydes and primary amines in [bmim]Br. The synthesized compounds were evaluated for their acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory potential by modified Ellman's method. The molecular interactions between the most active compound and the enzyme were analyzed by molecular docking. Among them, 3j displayed higher inhibitory activities than reference drug, galanthamine, with IC50 values of 2.05 and 5.77 µM, for AChE and BChE, respectively. Interestingly, all the compounds except 3b displayed higher BChE inhibitions than galanthamine with IC50 values ranging from 5.77 to 18.52 µM. Molecular docking of compound 3j inside the TcAChE and hBChE completely coincided with the inhibitory activities observed. The compound forms strong hydrogen bonding at the peripheral anionic site of AChE whereas on BChE, it had hydrophobic and mild polar interactions. An efficient and eco-friendly synthetic methodology has been developed to synthesize Schiff bases in a very short reaction time and excellent yields in ionic solvent, whereby the compounds from series 3 showed promising cholinesterase inhibitory activity.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Ghosh, Arun K.; Sean Fyvie, W.; Brindisi, Margherita
Design, synthesis, and evaluation of a new class of HIV-1 protease inhibitors containing diverse flexible macrocyclic P1'-P2' tethers are reported. Inhibitor 5a with a pyrrolidinone-derived macrocycle exhibited favorable enzyme inhibitory and antiviral activity (Ki = 13.2 nM, IC50 = 22 nM). Further incorporation of heteroatoms in the macrocyclic skeleton provided macrocyclic inhibitors 5m and 5o. These compounds showed excellent HIV-1 protease inhibitory (Ki = 62 pM and 14 pM, respectively) and antiviral activity (IC50 = 5.3 nM and 2.0 nM, respectively). Inhibitor 5o also remained highly potent against a DRV-resistant HIV-1 variant.
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Aitken, H; Poyser, N L
2001-01-01
The outputs of PGF(2 alpha), PGE2 and 6-keto-PGF(1 alpha)were similar from the day 22 guinea-pig placenta and sub-placenta in culture, except for PGE2 output from the sub-placenta which was lower. Between days 22 and 29 of pregnancy, the outputs of PGF(2 alpha), PGE2 and 6-keto-PGF(1 alpha)during the initial 2 h culture period increased 6.9-, 1.1- and 3.2-fold, respectively, from the placenta, and 2.1-, 1.4- and 2.2-fold, respectively, from the sub-placenta. Therefore, there was a relatively specific increase in PGF(2 alpha)production by the guinea-pig placenta between days 22 and 29 of pregnancy. The output of PGFM from the cultured placenta also increased between days 22 and 29, indicating that the increase in PGF(2 alpha)output was due to increased synthesis rather than to decreased metabolism. By comparing the amounts of prostaglandins produced by tissue homogenates during a 1 h incubation period, it appears that there is approximately a 2-fold increase in the amount of prostaglandin H synthase (PGHS) present in the guinea-pig placenta between days 22 and 29. NS-398 (a specific inhibitor of PGHS-2) and indomethacin (an inhibitor of both PGHS-1 and PGHS-2) both inhibited prostaglandin production by homogenates of day 22 and day 29 placenta. Indomethacin was more effective than NS-398, except for their actions on PGF(2 alpha)production by the day 29 placenta where indomethacin and NS-398 were equiactive. Indomethacin and NS-398 were both very effective at inhibiting the outputs of PGF(2 alpha), PGE2 and 6-keto-PGF(1 alpha)from the day 22 and day 29 placenta and sub-placenta in culture, indicating that prostaglandin production by the guinea-pig placenta and sub-placenta in culture is largely dependent upon the activity of PGHS-2. The high production of PGF(2 alpha)by the day 29 placenta is not dependent on the continual synthesis of fresh protein(s), as inhibitors of protein synthesis did not reduce PGF(2 alpha)output from the day 29 guinea-pig placenta in culture
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de Oliveira Lopes, Raquel; Romeiro, Nelilma Correia; de Lima, Cleverton Kleiton F; Louback da Silva, Leandro; de Miranda, Ana Luisa Palhares; Nascimento, Paulo Gustavo B D; Cunha, Fernando Q; Barreiro, Eliezer J; Lima, Lídia Moreira
2012-08-01
p38 mitogen-activated protein kinase (p38 MAPK) is an important signal transducing enzyme involved in many cellular regulations, including signaling pathways, pain and inflammation. Several p38 MAPK inhibitors have been developed as drug candidates to treatment of autoimmune disorders, such as rheumatoid arthritis. In this paper we reported the docking, synthesis and pharmacological activity of novel urea-derivatives (4a-e) designed as p38 MAPK inhibitors. These derivatives presented good theoretical affinity to the target p38 MAPK, standing out compound 4e (LASSBio-998), which showed a better score value compared to the prototype GK-00687. This compound was able to reduce in vitro TNF-α production and was orally active in a hypernociceptive murine model sensible to p38 MAPK inhibitors. Otherwise, compound 4e presented a dose-dependent analgesic effect in a model of antigen (mBSA)-induced arthritis and anti-inflammatory profile in carrageenan induced paw edema, indicating its potential as a new antiarthritis prototype. Copyright © 2012 Elsevier Masson SAS. All rights reserved.
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Formation of sodium bismuth titanate-barium titanate during solid-state synthesis
Hou, Dong; Aksel, Elena; Fancher, Chris M.; ...
2017-01-12
Phase formation of sodium bismuth titanate (Na 0.5Bi 0.5TiO 3 or NBT) and its solid solution with barium titanate (BaTiO 3 or BT) during the calcination process is studied using in situ high-temperature diffraction. The reactant powders were mixed and heated to 1000°C, while X-ray diffraction patterns were recorded continuously. Phase evolutions from starting materials to final perovskite products are observed, and different transient phases are identified. The formation mechanism of NBT and NBT–xBT perovskite structures is discussed, and a reaction sequence is suggested based on the observations. The in situ study leads to a new processing approach, which ismore » the use of nano-TiO 2, and gives insights to the particle size effect for solid-state synthesis products. Lastly, it was found that the use of nano-TiO 2 as reactant powder accelerates the synthesis process, decreases the formation of transient phases, and helps to obtain phase-pure products using a lower thermal budget.« less
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NASA Astrophysics Data System (ADS)
Boreyko, A. V.; Chausov, V. N.; Krasavin, E. A.; Ravnachka, I.; Stukova, S. I.
2011-07-01
The influence that inhibitors of repair and replicative DNA synthesis, 1-β-D-arabinofuranosyl-cytosine and hydroxyurea, have on the formation and repair kinetics of double-strand breaks (DSBs) in peripheral human blood lymphocytes under the influence of radiation with a different linear energy transfer (LET) (gamma quanta and accelerated heavy ions) is studied. It is demonstrated that lithium and boron ions with LETs of 20 and 40 keV/μm, respectively, possess higher biological effectiveness with respect to the DNA DSB induction criterion. The value of the relative biological effectiveness of accelerated lithium and boron ions is 1.5 ± 0.1 and 1.6 ± 0.1, respectively. It is found that, upon cell irradiation by gamma quanta in the absence of inhibitors, efficient DNA DSB repair is observed during incubation. Under the conditions of cell incubation and in the presence of inhibitors, some growth in the number of DNA DSBs, rather than a reduction, is observed after 5-h incubation. In the case of the action of accelerated boron ions (as well as gamma quanta), under normal conditions, the efficient repair of induced DNA lesions takes place. Unlike the action of gamma quanta, in the case of cell incubation in the presence of radiomodifiers, the number of induced DNA DSBs falls. These results may testify to the fact that the repair of double-strand DNS breaks takes place under the action of ionizing radiation with a different LET on mammalian cells in the presence of DNA synthesis inhibitors Ara-C and HU. It is concluded that, for cells subject to gamma irradiation, no DNA DSB repair is observed due to the large contribution of single-strand incision DNA breaks formed in the postradiation period in the course of excision nucleotide repair.
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Ahmaditaba, Mohammad Ali; Houshdar Tehrani, Mohammad Hassan; Zarghi, Afshin; Shahosseini, Sorayya; Daraei, Bahram
2018-01-01
A new series of peptide-like derivatives containing different aromatic amino acids and possessing pharmacophores of COX-2 inhibitors as SO2Me or N3 attached to the para position of an end phenyl ring was synthesized for evaluation as selective cyclooxygenase-2 (COX-2) inhibitors. The synthetic reactions were based on the solid phase peptide synthesis method using Wang resin. One of the analogues, i.e., compound 2d, as the representative of these series was recognized as the most effective and the highest selective COX-2 inhibitor with IC50 value of 0.08 μM and COX-2 selectivity index of 351.2, among the other synthesized compounds. Molecular docking study was operated to determine possible binding models of compound 2d to COX-2 enzyme. The study showed that the p-azido-phenyl fragment of 2d occupied inside the secondary COX-2 binding site (Arg513, and His90). The structure-activity relationships acquired disclosed that compound 2d with 4-(azido phenyl) group as pharmacophore and histidine as amino acid gives the essential geometry to provide inhibition of the COX-2 enzyme with high selectivity. Compound 2d can be a good candidate for the development of new hits of COX-2 inhibitors.
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Jinsmaa, Yunden; Sullivan, Patti; Holmes, Courtney; Kopin, Irwin J.; Sharabi, Yehonatan
2016-01-01
According to the catecholaldehyde hypothesis, the toxic dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL) contributes to the loss of nigrostriatal dopaminergic neurons in Parkinson’s disease. Monoamine oxidase-A (MAO-A) catalyzes the conversion of intraneuronal dopamine to DOPAL and may serve as a therapeutic target. The “cheese effect”—paroxysmal hypertension evoked by tyramine-containing foodstuffs—limits clinical use of irreversible MAO-A inhibitors. Combined MAO-A/B inhibition decreases DOPAL production in rat pheochromocytoma PC12 cells, but whether reversible MAO-A inhibitors or MAO-B inhibitors decrease endogenous DOPAL production is unknown. We compared the potencies of MAO inhibitors in attenuating DOPAL production and examined possible secondary effects on dopamine storage, constitutive release, synthesis, and auto-oxidation. Catechol concentrations were measured in cells and medium after incubation with the irreversible MAO-A inhibitor clorgyline, three reversible MAO-A inhibitors, or the MAO-B inhibitors selegiline or rasagiline for 180 minutes. Reversible MAO-A inhibitors were generally ineffective, whereas clorgyline (1 nM), rasagiline (500 nM), and selegiline (500 nM) decreased DOPAL levels in the cells and medium. All three drugs also increased dopamine and norepinephrine, decreased 3,4-dihydroxyphenylalanine, and increased cysteinyl-dopamine concentrations in the medium, suggesting increased vesicular uptake and constitutive release, decreased dopamine synthesis, and increased dopamine spontaneous oxidation. In conclusion, clorgyline, rasagiline, and selegiline decrease production of endogenous DOPAL. At relatively high concentrations, the latter drugs probably lose their selectivity for MAO-B. Possibly offsetting increased formation of potentially toxic oxidation products and decreased formation of DOPAL might account for the failure of large clinical trials of MAO-B inhibitors to demonstrate slowing of neurodegeneration in
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Formation Mechanism of Spherical TiC in Ni-Ti-C System during Combustion Synthesis.
Zhu, Guoliang; Wang, Wei; Wang, Rui; Zhao, Chuanbao; Pan, Weitao; Huang, Haijun; Du, Dafan; Wang, Donghong; Shu, Da; Dong, Anping; Sun, Baode; Jiang, Sheng; Pu, Yilong
2017-08-29
The formation mechanism of TiC particles in a Ni-Ti-C system were revealed by using differential thermal analysis (DTA), XRD, and SEM to identify the reaction products in different temperature ranges. The results indicated that the synthesis mechanism of TiC in Ni-Ti-C system was complex; several reactions were involved in the combustion synthesis of TiC-Ni composite. The Ni-Ti intermediate phases play important roles during the formation of TiC. Moreover, the influence of heating rate on the size range of TiC was also discussed.
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Formation Mechanism of Spherical TiC in Ni-Ti-C System during Combustion Synthesis
Zhu, Guoliang; Wang, Wei; Wang, Rui; Zhao, Chuanbao; Pan, Weitao; Huang, Haijun; Du, Dafan; Wang, Donghong; Shu, Da; Dong, Anping; Sun, Baode; Jiang, Sheng; Pu, Yilong
2017-01-01
The formation mechanism of TiC particles in a Ni-Ti-C system were revealed by using differential thermal analysis (DTA), XRD, and SEM to identify the reaction products in different temperature ranges. The results indicated that the synthesis mechanism of TiC in Ni-Ti-C system was complex; several reactions were involved in the combustion synthesis of TiC-Ni composite. The Ni-Ti intermediate phases play important roles during the formation of TiC. Moreover, the influence of heating rate on the size range of TiC was also discussed. PMID:28850088
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Ogura, Hirotsugu; Tsukumo, Yoshinori; Department of Bioengineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501
2008-04-01
The transcription factor nuclear factor {kappa}B (NF-{kappa}B) plays a major role in the inducible resistance to death receptor-mediated apoptosis. It has been established that the protein synthesis inhibitor cycloheximide (CHX) sensitizes many types of cells to tumor necrosis factor (TNF)-{alpha}-induced apoptosis, mainly due to its ability to block de novo synthesis of cellular FLICE-inhibitory protein (c-FLIP). Nevertheless, we have surprisingly found that CHX, as well as its structural analogue acetoxycycloheximide (Ac-CHX), prevents TNF-{alpha}-mediated activation of NF-{kappa}B and caspase-8 in human lung carcinoma A549 cells. Both CHX and Ac-CHX reduced the expression of cell surface TNF receptor 1 (TNF-R1) in amore » dose-dependent manner, while Ac-CHX was approximately 100-fold more effective than CHX. Consistent with this observation, Ac-CHX induced the proteolytic cleavage of TNF-R1 and its release into the culture medium. CHX and Ac-CHX profoundly decreased constitutive and inducible expression of c-FLIP, whereas these compounds potentiated TNF-{alpha}-induced caspase-8 activation only when metalloprotease inhibitors were present. Thus, our results indicate that ectodomain shedding of TNF-R1 induced by protein synthesis inhibitors regulates TNF-{alpha}-mediated activation of NF-{kappa}B and caspase-8.« less
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Engelhart, Curtis A.; Aldrich, Courtney C.
2013-01-01
MbtA catalyzes the first committed step of mycobactin biosynthesis in Mycobacterium tuberculosis (Mtb) and is responsible for the incorporation of salicylic acid into the mycobactin siderophores. 5′-O-[N-(Salicyl)sulfamoyl]adenosine (Sal-AMS) is an extremely potent nucleoside inhibitor of MbtA that possesses excellent activity against whole-cell Mtb, but suffers from poor bioavailability. In an effort to improve the bioavailability, we have designed four conformationally constrained analogues of Sal-AMS that remove two rotatable bonds and the ionized sulfamate group based on computational and structural studies. Herein we describe the synthesis, biochemical, and microbiological evaluation of chromone-, quinolone-, and benzoxazinone-3-sulfonamide derivatives of Sal-AMS. We developed new chemistry to assemble these three heterocycles from common β-ketosulfonamide intermediates. The synthesis of the chromone- and quinolone-3-sulfonamide intermediates features formylation of a β-ketosulfonamide employing dimethylformamide dimethyl acetal to afford an enaminone that can react intramolecularly with a phenol or intermolecularly with a primary amine via addition-elimination reaction(s). The benzoxazinone-3-sulfonamide was prepared by nitrosation of a β-ketosulfonamide followed by intramolecular nucleophilic aromatic substitution. Mitsunobu coupling of these bicyclic sulfonamides with a protected adenosine derivative followed by global deprotection provides a concise synthesis of the respective inhibitors. PMID:23805993
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Hajbi, Youssef; Neagoie, Cléopatra; Biannic, Bérenger; Chilloux, Aurélie; Vedrenne, Emeline; Baldeyrou, Brigitte; Bailly, Christian; Mérour, Jean-Yves; Rosca, Sorin; Routier, Sylvain; Lansiaux, Amélie
2010-11-01
New 1,5-dihydro-4-(substituted phenyl)-3H-furo[3,4-b]carbazol-3-ones were synthesised via a key step Diels-Alder reaction under microwave irradiation. 3-Formylindole was successfully used in a 6-step synthesis to obtain those complex heterocycles. The Diels-Alder reaction generating the carbazole ring was optimised under thermal conditions or microwave irradiation. After cleavage of functional groups, DNA binding, topoisomerase inhibition and cytotoxic properties of the new-formed furocarbazoles were investigated. These carbazoles do not present a strong interaction with the DNA, and do not modify the relaxation of the DNA in the presence of topoisomerase I or II except for one promising compound. This compound is a potent topoisomerase II inhibitor, and its cellular activity is not moderated compared to etoposide. The synthesis of these molecules allowed the generalisation of the method using indole and 5-OBn indole and several benzaldehydes. The synthesis of these molecules produced chemical structures endowed with promising cytotoxic and topoisomerase II inhibition activities. Copyright © 2010 Elsevier Masson SAS. All rights reserved.
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Microwave-assisted synthesis of novel purine nucleosides as selective cholinesterase inhibitors.
Schwarz, S; Csuk, R; Rauter, A P
2014-04-21
Alzheimer's disease (AD), the most common form of senile dementia, is characterized by high butyrylcholinesterase (BChE) levels in the brain in later AD stages, for which no treatment is available. Pursuing our studies on selective BChE inhibitors, that may contribute to understand the role of this enzyme in disease progression, we present now microwave-assisted synthesis and anticholinesterase activity of a new nucleoside series embodying 6-chloropurine or 2-acetamido-6-chloropurine linked to D-glucosyl, D-galactosyl and D-mannosyl residues. It was designed to assess the contribution of sugar stereochemistry, purine structure and linkage to the sugar for cholinesterase inhibition efficiency and selectivity. Compounds were subjected to Ellman's assay and their inhibition constants determined. The α-anomers were the most active compounds, while selectivity for BChE or acetylcholinesterase (AChE) inhibition could be tuned by the purine base, by the glycosyl moiety and by N(7)-ligation. Some of the nucleosides were far more potent than the drug galantamine, and the most promising competitive and selective BChE inhibitor, the N(7)-linked 2-acetamido-α-D-mannosylpurine, showed a Ki of 50 nM and a selectivity factor of 340 fold for BChE over AChE.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
R Daher; M Coincon; M Fonvielle
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 highmore » 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.« less
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Discovery and Structure Enabled Synthesis of 2,6-Diaminopyrimidin-4-one IRAK4 Inhibitors
DOE Office of Scientific and Technical Information (OSTI.GOV)
Seganish, W. Michael; Fischmann, Thierry O.; Sherborne, Brad
2015-08-13
We report the identification and synthesis of a series of aminopyrimidin-4-one IRAK4 inhibitors. Through high throughput screening, an aminopyrimidine hit was identified and modified via structure enabled design to generate a new, potent, and kinase selective pyrimidin-4-one chemotype. This chemotype is exemplified by compound 16, which has potent IRAK4 inhibition activity (IC50 = 27 nM) and excellent kinase selectivity (>100-fold against 99% of 111 tested kinases), and compound 31, which displays potent IRAK4 activity (IC50 = 93 nM) and good rat bioavailability (F = 42%).
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Design, Synthesis and Evaluation of 2,5-Diketopiperazines as Inhibitors of the MDM2-p53 Interaction.
Pettersson, Mariell; Quant, Maria; Min, Jaeki; Iconaru, Luigi; Kriwacki, Richard W; Waddell, M Brett; Guy, R Kiplin; Luthman, Kristina; Grøtli, Morten
2015-01-01
The transcription factor p53 is the main tumour suppressor in cells and many cancer types have p53 mutations resulting in a loss of its function. In tumours that retain wild-type p53 function, p53 activity is down-regulated by MDM2 (human murine double minute 2) via a direct protein-protein interaction. We have designed and synthesised two series of 2,5-diketopiperazines as inhibitors of the MDM2-p53 interaction. The first set was designed to directly mimic the α-helical region of the p53 peptide, containing key residues in the i, i+4 and i+7 positions of a natural α-helix. Conformational analysis indicated that 1,3,6-trisubstituted 2,5-diketopiperazines were able to place substituents in the same spatial orientation as an α-helix template. The key step of the synthesis involved the cyclisation of substituted dipeptides. The other set of tetrasubstituted 2,5-diketopiperazines were designed based on structure-based docking studies and the Ugi multicomponent reaction was used for the synthesis. This latter set comprised the most potent inhibitors which displayed micromolar IC50-values in a biochemical fluorescence polarisation assay.
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Design, Synthesis and Evaluation of 2,5-Diketopiperazines as Inhibitors of the MDM2-p53 Interaction
Pettersson, Mariell; Quant, Maria; Min, Jaeki; Iconaru, Luigi; Kriwacki, Richard W.; Waddell, M. Brett; Guy, R. Kiplin; Luthman, Kristina; Grøtli, Morten
2015-01-01
The transcription factor p53 is the main tumour suppressor in cells and many cancer types have p53 mutations resulting in a loss of its function. In tumours that retain wild-type p53 function, p53 activity is down-regulated by MDM2 (human murine double minute 2) via a direct protein—protein interaction. We have designed and synthesised two series of 2,5-diketopiperazines as inhibitors of the MDM2-p53 interaction. The first set was designed to directly mimic the α-helical region of the p53 peptide, containing key residues in the i, i+4 and i+7 positions of a natural α-helix. Conformational analysis indicated that 1,3,6-trisubstituted 2,5-diketopiperazines were able to place substituents in the same spatial orientation as an α-helix template. The key step of the synthesis involved the cyclisation of substituted dipeptides. The other set of tetrasubstituted 2,5-diketopiperazines were designed based on structure-based docking studies and the Ugi multicomponent reaction was used for the synthesis. This latter set comprised the most potent inhibitors which displayed micromolar IC50-values in a biochemical fluorescence polarisation assay. PMID:26427060
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NASA Astrophysics Data System (ADS)
Hu, Xiuqin; Wang, Disha; Tong, Yi; Tong, Linjiang; Wang, Xia; Zhu, Lili; Xie, Hua; Li, Shiliang; Yang, You; Xu, Yufang
2017-11-01
The synthesis of a series of ribose-modified anilinopyrimidine derivatives was efficiently achieved by utilizing DBU or tBuOLi-promoted coupling of ribosyl alcohols with 2,4,5-trichloropyrimidine as key step. Preliminary biological evaluation of this type of compounds as new EGFR tyrosine kinase inhibitors for combating EGFR L858R/T790M mutant associated with drug resistance in the treatment of non-small cell lung cancer revealed that 3-N-acryloyl-5-O-anilinopyrimidine ribose derivative 1a possessed potent and specific inhibitory activity against EGFR L858R/T790M over WT EGFR. Based upon molecular docking studies of the binding mode between compound 1a and EGFR, the distance between the Michael receptor and the pyrimidine scaffold is considered as an important factor for the inhibitory potency and future design of selective EGFR tyrosine kinase inhibitors against EGFR L858R/T790M mutants.
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Synthesis and biological evaluation of di-aryl urea derivatives as c-Kit inhibitors.
Ravez, Séverine; Arsenlis, Stéphane; Barczyk, Amélie; Dupont, Anthony; Frédérick, Raphaël; Hesse, Stéphanie; Kirsch, Gilbert; Depreux, Patrick; Goossens, Laurence
2015-11-15
Inhibition of receptor tyrosine kinases (RTKs) continued to be a successful approach for the treatment of many types of human cancers and many potent small molecules kinase inhibitors have been discovered the last decade. In the present study, we describe the synthesis of thienopyrimidine derivatives and their pharmacological evaluation against nine kinases (EGFR, PDGFR-ß, c-Kit, c-Met, Src, Raf, VEGFR-1, -2 and -3). Most of the synthesized compounds showed from moderate to potent activities against c-Kit with IC50 values in the nanomolar range. Among them, 4-anilino(urea)thienopyrimidine analogs showed selectivity and potent c-Kit inhibition with IC50 values less than 6 nM. Docking simulation was performed for the most promising compound 9 into the c-Kit active site to determine the potential binding mode. This study reveal that the 4-anilino(urea)thienopyrimidine is an interesting scaffold to design novel potent and selective c-Kit inhibitors which may make promising candidates for cancers where c-Kit receptors are overexpressed. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Li, Hailan; Yun, Hye-Young; Baek, Kwang Jin; Kwon, Nyoun Soo; Park, Kyoung-Chan; Kim, Dong-Seok
2014-03-01
The purpose of this study was to investigate effects of myriocin, an inhibitor of serine palmitoyltransferase, on melanogenesis. It was found that myriocin increased melanin synthesis in a concentration-dependent manner. Moreover, myriocin up-regulated microphthalmia-associated transcription factor (MITF) and tyrosinase expression via phosphorylation of CREB, but it did not directly activate tyrosinase, a rate-limiting melanogenic enzyme. Furthermore, we demonstrated increased melanin synthesis with myriocin on a pigmented skin equivalent model established using Cervi cornus Colla (deer antler glue). One and 5 microM of myriocin darkened the color of the skin equivalent. These results suggest that myriocin may have potential effects for the treatment of hypopigmentary skin diseases like vitiligo or for sunless tanning.
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Hydrothermal Synthesis of Analcime from Kutingkeng Formation Mudstone
NASA Astrophysics Data System (ADS)
Hsiao, Yin-Hsiu; Chen, Kuan-Ting; Ray, Dah-Tong
2015-04-01
In southwest of Taiwan, the foothill located in Tainan-Kaohsiung city is the exposed area of Pliocene strata to early Pleistocene strata. The strata are about a depth of five thousand, named as Kutigkeng Formation. The outcrop of Kutigkeng Formation is typical badlands, specifically called 'Moon World.' It is commonly known as no important economic applications of agricultural land. The mineral compositions of Kutingkeng Formation are quartz, clay minerals and feldspar. The clay minerals consist of illite, clinochlore and swelling clays. To study how the phase and morphology of analcime formed by hydrothermal synthesis were affected, analcime was synthesized from the mudstone of Kutinkeng Formation with microwave hydrothermal reaction was investigated. The parameters of the experiment were the reaction temperature, the concentration of mineralizer, solids/liquid ratio and time. The sodium silicate (Na2SiO3) were used as mineralizer. The results showed that the analcime could be synthesized by hydrothermal reaction above 180° from Kutinkeng Formation mudstone samples. At the highest temperature (240°) of this study, the high purity analcime could be produced. When the concentration of Na2SiO3=3~6M, analcime could be synthesized at 240°. The best solids/liquid ratio was approximate 1 to 5. The hydrothermal reaction almost was completed after 4 hours.
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Nguyen, Trung Xuan; Morrell, Andrew; Conda-Sheridan, Martin; Marchand, Christophe; Agama, Keli; Bermingam, Alun; Stephen, Andrew G.; Chergui, Adel; Naumova, Alena; Fisher, Robert; O’Keefe, Barry R.; Pommier, Yves; Cushman, Mark
2012-01-01
Substances with dual tyrosyl-DNA phosphodiesterase I - topoisomerase I inhibitory activity in one low molecular weight compound would constitute a unique class of anticancer agents that could potentially have significant advantages over drugs that work against the individual enzymes. The present study demonstrates the successful synthesis and evaluation of the first dual Top1-Tdp1 inhibitors, which are based on the indenoisoquinoline chemotype. One bis(indenoisoquinoline) had significant activity against human Tdp1 (IC50 = 1.52 ± 0.05 μM), and it was also equipotent to camptothecin as a Top1 inhibitor. Significant insights into enzyme-drug interactions were gained via structure-activity relationship studies of the series. The present results also document the failure of the previously reported sulfonyl ester pharmacophore to confer Tdp1 inhibition in this indenoisoquinoline class of inhibitors, even though it was demonstrated to work well for the steroid NSC 88915 (7). The current study will facilitate future efforts to optimize dual Top1-Tdp1 inhibitors. PMID:22536944
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Ryu, Victor; McClements, David J; Corradini, Maria G; McLandsborough, Lynne
2018-04-15
The objective of this research was to study the impact of ripening inhibitor level and type on the formation, stability, and activity of antimicrobial thyme oil nanoemulsions formed by spontaneous emulsification. Oil-in-water antimicrobial nanoemulsions (10 wt%) were formed by titrating a mixture of essential oil, ripening inhibitor, and surfactant (Tween 80) into 5 mM sodium citrate buffer (pH 3.5). Stable nanoemulsions containing small droplets (d < 70 nm) were formed. The antimicrobial activity of the nanoemulsions decreased with increasing ripening inhibitor concentration which was attributed to a reduction in the amount of hydrophobic antimicrobial constituents transferred to the separated hydrophobic domain, mimicking bacterial cell membranes, by using dialysis and chromatography. The antimicrobial activity of the nanoemulsions also depended on the nature of the ripening inhibitor used: palm ≈ corn > canola > coconut which also depended on their ability to transfer hydrophobic antimicrobial constituents to the separated hydrophobic domain. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Grijalvo, Santiago; Bedia, Carmen; Triola, Gemma; Casas, Josefina; Llebaria, Amadeu; Teixidó, Jordi; Rabal, Obdulia; Levade, Thierry; Delgado, Antonio; Fabriàs, Gemma
2006-10-01
The synthesis of novel N-acylethanolamines and their use as inhibitors of the aCDase is reported here. The compounds are either 2-oxooctanamides or oleamides of sphingosine analogs featuring a 3-hydroxy-4,5-hexadecenyl tail replaced by ether or thioether moieties. It appears that, within the 2-oxooctanamide family, the C3-OH group of the sphingosine molecule is required for inhibition both in vitro and in cultured cells. Furthermore, although the (E)-4 double bond is not essential for inhibitory activity, the (E) configuration is required, since the analogue with a (Z)-4 unsaturation was not inhibitory. None of the oleamides inhibited the aCDase in vitro. Conversely, with the exception of N-oleoylethanolamine and its analogs with S-decyl and S-hexadecyl substituents, all the synthesized oleamides inhibited the aCDase in cultured cells, although with a relatively low potency. We conclude that novel aCDase inhibitors can evolve from N-acylation of sphingoid bases with electron deficient-acyl groups. In contrast, chemical modification of the N-oleoylsphingosine backbone does not seem to offer an appropriate strategy to obtain aCDase inhibitors.
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Mipomersen, an antisense apolipoprotein B synthesis inhibitor.
Bell, Damon A; Hooper, Amanda J; Burnett, John R
2011-02-01
mipomersen is a second-generation antisense oligonucleotide (ASO) targeted to human apolipoprotein (apo) B-100, a large protein synthesized by the liver that plays a fundamental role in human lipoprotein metabolism. Mipomersen predominantly distributes to the liver and decreases the production of apoB-100, the primary structural protein of the atherogenic lipoproteins including low density lipoprotein (LDL), thereby reducing plasma LDL-cholesterol and apoB-100 concentrations. the mode of action, preclinical development and clinical trials of mipomersen, an antisense apoB synthesis inhibitor. The paper provides an understanding of the pharmacokinetic and pharmacodynamic characteristics of mipomersen and insight into its clinical efficacy and safety. In clinical trials, mipomersen produced dose-dependent and prolonged reductions in LDL-cholesterol and other apoB-containing lipoproteins, including lipoprotein (a) [Lp(a)] in healthy volunteers and in patients with mild to moderate hypercholesterolemia. Mipomersen has been shown to decrease apoB, LDL-cholesterol and Lp(a) in patients with heterozygous and homozygous familial hypercholesterolemia on maximally tolerated lipid-lowering therapy. mipomersen shows promise as an adjunctive agent by reducing apoB-containing lipoproteins in patients at high risk of atherosclerotic cardiovascular disease who are not at target or are intolerant of statins. Although the short-term efficacy and safety of mipomersen has been established, concern exists regarding the long-term potential for hepatic steatosis with this ASO.
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Dgachi, Youssef; Bautista-Aguilera, Oscar M; Benchekroun, Mohamed; Martin, Hélène; Bonet, Alexandre; Knez, Damijan; Godyń, Justyna; Malawska, Barbara; Gobec, Stanislav; Chioua, Mourad; Janockova, Jana; Soukup, Ondrej; Chabchoub, Fakher; Marco-Contelles, José; Ismaili, Lhassane
2016-05-14
We report herein the straightforward two-step synthesis and biological assessment of novel racemic benzochromenopyrimidinones as non-hepatotoxic, acetylcholinesterase inhibitors with antioxidative properties. Among them, compound 3Bb displayed a mixed-type inhibition of human acetylcholinesterase (IC50 = 1.28 ± 0.03 μM), good antioxidant activity, and also proved to be non-hepatotoxic on human HepG2 cell line.
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Ghosh, Arun K.; Parham, Garth L.; Martyr, Cuthbert D.; Nyalapatla, Prasanth R.; Osswald, Heather L.; Agniswamy, Johnson; Wang, Yuan-Fang; Amano, Masayuki; Weber, Irene T.; Mitsuya, Hiroaki
2013-01-01
The design, synthesis, and biological evaluation of a series of HIV-1 protease inhibitors incorporating stereochemically defined fused tricyclic P2-ligands are described. Various substituent effects were investigated in order to maximize the ligand-binding site interactions in the protease active site. Inhibitors 16a and 16f showed excellent enzyme inhibitory and antiviral activity while incorporation of sulfone functionality resulted in a decrease in potency. Both inhibitors 16a and 16f have maintained activity against a panel of multidrug resistant HIV-1 variants. A high-resolution X-ray crystal structure of 16a-bound HIV-1 protease revealed important molecular insights into the ligand-binding site interactions which may account for the inhibitor’s potent antiviral activity and excellent resistance profiles. PMID:23947685
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Bongard, Robert D; Lepley, Michael; Thakur, Khushabu; Talipov, Marat R; Nayak, Jaladhi; Lipinski, Rachel A Jones; Bohl, Chris; Sweeney, Noreena; Ramchandran, Ramani; Rathore, Rajendra; Sem, Daniel S
2017-05-31
Protein tyrosine phosphatases (PTPs) like dual specificity phosphatase 5 (DUSP5) and protein tyrosine phosphatase 1B (PTP1B) are drug targets for diseases that include cancer, diabetes, and vascular disorders such as hemangiomas. The PTPs are also known to be notoriously difficult targets for designing inihibitors that become viable drug leads. Therefore, the pipeline for approved drugs in this class is minimal. Furthermore, drug screening for targets like PTPs often produce false positive and false negative results. Studies presented herein provide important insights into: (a) how to detect such artifacts, (b) the importance of compound re-synthesis and verification, and (c) how in situ chemical reactivity of compounds, when diagnosed and characterized, can actually lead to serendipitous discovery of valuable new lead molecules. Initial docking of compounds from the National Cancer Institute (NCI), followed by experimental testing in enzyme inhibition assays, identified an inhibitor of DUSP5. Subsequent control experiments revealed that this compound demonstrated time-dependent inhibition, and also a time-dependent change in color of the inhibitor that correlated with potency of inhibition. In addition, the compound activity varied depending on vendor source. We hypothesized, and then confirmed by synthesis of the compound, that the actual inhibitor of DUSP5 was a dimeric form of the original inhibitor compound, formed upon exposure to light and oxygen. This compound has an IC 50 of 36 μM for DUSP5, and is a competitive inhibitor. Testing against PTP1B, for selectivity, demonstrated the dimeric compound was actually a more potent inhibitor of PTP1B, with an IC 50 of 2.1 μM. The compound, an azo-bridged dimer of sulfonated naphthol rings, resembles previously reported PTP inhibitors, but with 18-fold selectivity for PTP1B versus DUSP5. We report the identification of a potent PTP1B inhibitor that was initially identified in a screen for DUSP5, implying common
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Liu, Xiao-Wei; Guo, Ya; Tao, Andi; Fischer, Michael; Sun, Tian-Jun; Moghadam, Peyman Z; Fairen-Jimenez, David; Wang, Shu-Dong
2017-10-17
In this work, we show a solvent-free "explosive" synthesis (SFES) method for the ultrafast and low-cost synthesis of metal-formate frameworks (MFFs). A combination of experiments and in-depth molecular modelling analysis - using grand canonical Monte Carlo (GCMC) simulations - of the adsorption performance of the synthesized nickel-formate framework (Ni-FA) revealed extremely high quality products with permanent porosity, prominent CH 4 /N 2 selectivity (ca. 6.0), and good CH 4 adsorption capacity (ca. 0.80 mmol g -1 or 33.97 cm 3 cm -3 ) at 1 bar and 298 K. This performance is superior to those of many other state-of-the-art porous materials.
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Amino Compounds as Inhibitors of De Novo Synthesis of Chlorobenzenes
NASA Astrophysics Data System (ADS)
Wang, Si-Jia; He, Pin-Jing; Lu, Wen-Tao; Shao, Li-Ming; Zhang, Hua
2016-04-01
The inhibitory effects of four amino compounds on the formation of chlorobenzenes (CBzs) - dioxin precursors and indicators, and the inhibitory mechanisms were explored. The results show NH4H2PO4 can decrease the total yields of CBzs (1,2di-CBz, 1,3di-CBz, 1,4di-CBz, penta-CBz and hexa-CBz) by 98.1%±1.6% and 96.1%±0.7% under air and nitrogen flow. The inhibitory effects indicated by the total yields of CBzs follow the order NH4H2PO4 > NH4HF2 > (NH4)2SO4 > NH4Br under air flow and NH4H2PO4 ≈ (NH4)2SO4 ≈ NH4HF2 >NH4Br under nitrogen flow. The inhibition mechanism revealed by thermal analysis that CuCl2 was converted to CuPO3 by reacting with NH4H2PO4 below 200 °C, which can block the transfer of chlorine and formation of C-Cl bonds at 350 °C. The effects of the other three inhibitors were weaker because their reactions with CuCl2, which form other copper compounds, and the reaction of CuCl2 with carbon, which forms C-Cl bonds, were almost simultaneous and competitive. Oxygen influenced the yield of CBzs obviously, and the total yield of five CBzs sharply increased with oxygen. Because of their high efficiency, low environmental impact, low cost, and availability, amino compounds - especially NH4H2PO4 - can be utilized as inhibitors of CBzs during incineration.
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Salgueiro, Daniela A L; Sousa, Cristina E A; Fortes, A Gil; Alves, M José
2012-12-01
This comprehensive review deals with the synthesis of 1-azafagomine, analogs, and derivatives having the Diels-Alder cycloaddition as the key step. Most of the compounds referred are racemic or have been resolved by lipase transesterification. There are two asymmetric cycloadditions leading to 1-azafagomine or to an analog. In one case both enantiomers of 1-azafagomine were prepared together with a pair of derivatives. The study comprises glycosidase inhibition studies of the target compounds to a set of glycosidic enzymes, and evidenced molecular features that enhance or diminish their activity as glycosidase inhibitors.
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Miura, Shin-Ichiro; Suematsu, Yasunori; Matsuo, Yoshino; Tomita, Sayo; Nakayama, Asuka; Goto, Masaki; Arimura, Tadaaki; Kuwano, Takashi; Yahiro, Eiji; Saku, Keijiro
2016-11-01
A recent clinical study indicated that an angiotensin II (Ang II) type 1 (AT 1 ) receptor-neprilysin inhibitor (ARNi) designated LCZ696 (sacubitril/valsartan, as combined sodium complex) was superior to enalapril at reducing the risks of death and hospitalization due to heart failure. Therefore, we investigated the possible mechanisms of the beneficial effect of LCZ696, in which the inhibition of neprilysin enhances atrial natriuretic peptide (NP) or brain NP (ANP or BNP)-evoked signals that can block Ang II/AT 1 receptor-induced aldosterone (Ald) synthesis in human adrenocortical cells. The binding affinity of valsartan+LBQ657 (active moiety of sacubitril) to the AT 1 receptor was greater than that of valsartan alone in an AT 1 receptor-expressing human embryonic kidney cell-based assay. There was no difference in the dissociation from the AT 1 receptor between valsartan+LBQ657 and valsartan alone. In Ang II-sensitized human adrenocortical cells, ANP or BNP alone, but not LBQ657 or valsartan alone, significantly decreased Ald synthesis. The level of suppression of Ald synthesis by ANP or BNP with LBQ657 was greater than that by ANP or BNP without LBQ657. The suppression of ANP was blocked by inhibitors of regulator of G-protein signaling proteins and cyclic GMP-dependent protein kinase. The inhibition of neprilysin did not change the mRNA levels of the AT 1 receptor, ANP receptor A, regulator of G-protein signaling protein, renin or 3β-hydroxysteroid dehydrogenases. In conclusion, the inhibition of neprilysin by LBQ657 enhances the NP-evoked signals that can block Ang II/AT 1 receptor-induced Ald synthesis in human adrenocortical cells.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Kozlkowski, A.P.; Campiani, G.; Saxena, A.
1995-12-31
Synthesis of four new pyrimidone analogues of the acetyicholinesterase (AChE) inhibitor huperzine A are reported together with the inhibitory potendes of these compounds for foetal bovine calf serum AChE; t3-lactone formation followed by a thermal cycloreversion reaction serves as the key step for introduction of the ethylidene appendage of analogue 12 in the stereochemically correct form.
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Protein synthesis in geostimulated root caps
NASA Technical Reports Server (NTRS)
Feldman, L. J.
1982-01-01
A study is presented of the processes occurring in the root cap of corn which are requisite for the formation of root cap inhibitor and which can be triggered or modulated by both light and gravity. The results of this study indicate the importance of protein synthesis for light-induced gravitropic bending in roots. Root caps in which protein synthesis is prevented are unable to induce downward bending. This suggests that light acts by stimulating proteins which are necessary for the translation of the gravitropic stimulus into a growth response (downward bending). The turnover of protein with time was also examined in order to determine whether light acts by stimulating the synthesis of unique proteins required for downward growth. It is found that auxin in combination with light allows for the translation of the gravitropic stimulus into a growth response at least in part through the modification of protein synthesis. It is concluded that unique proteins are stimulated by light and are involved in promoting the downward growth in roots which are responding to gravity.
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Rota, Paola; Cirillo, Federica; Piccoli, Marco; Gregorio, Antonio; Tettamanti, Guido; Allevi, Pietro; Anastasia, Luigi
2015-10-05
Previous studies demonstrated that reducing the GM3 content in myoblasts increased the cell resistance to hypoxic stress, suggesting that a pharmacological inhibition of the GM3 synthesis could be instrumental for the development of new treatments for ischemic diseases. Herein, the synthesis of several dephosphonated CMP-Neu5Ac congeners and their anti-GM3-synthase activity is reported. Biological activity testes revealed that some inhibitors almost completely blocked the GM3-synthase activity in vitro and reduced the GM3 content in living embryonic kidney 293A cells, eventually activating the epidermal growth factor receptor (EGFR) signaling cascade. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Receptor-mediated activation of nitric oxide synthesis by arginine in endothelial cells
Joshi, Mahesh S.; Ferguson, T. Bruce; Johnson, Fruzsina K.; Johnson, Robert A.; Parthasarathy, Sampath; Lancaster, Jack R.
2007-01-01
Arginine contains the guanidinium group and thus has structural similarity to ligands of imidazoline and α-2 adrenoceptors (α-2 AR). Therefore, we investigated the possibility that exogenous arginine may act as a ligand for these receptors in human umbilical vein endothelial cells and activate intracellular nitric oxide (NO) synthesis. Idazoxan, a mixed antagonist of imidazoline and α-2 adrenoceptors, partly inhibited l-arginine-initiated NO formation as measured by a Griess reaction. Rauwolscine, a highly specific antagonist of α-2 AR, at very low concentrations completely inhibited NO formation. Like l-arginine, agmatine (decarboxylated arginine) also activated NO synthesis, however, at much lower concentrations. We found that dexmedetomidine, a specific agonist of α-2 AR was very potent in activating cellular NO, thus indicating a possible role for α-2 AR in l-arginine-mediated NO synthesis. d-arginine also activated NO production and could be inhibited by imidazoline and α-2 AR antagonists, thus indicating nonsubstrate actions of arginine. Pertussis toxin, an inhibitor of G proteins, attenuated l-arginine-mediated NO synthesis, thus indicating mediation via G proteins. l-type Ca2+ channel blocker nifedipine and phospholipase C inhibitor U73122 inhibited NO formation and thus implicated participation of a second messenger pathway. Finally, in isolated rat gracilis vessels, rauwolscine completely inhibited the l-arginine-initiated vessel relaxation. Taken together, these data provide evidence for binding of arginine to membrane receptor(s), leading to the activation of endothelial NO synthase (eNOS) NO production through a second messenger pathway. These findings provide a previously unrecognized mechanistic explanation for the beneficial effects of l-arginine in the cardiovascular system and thus provide new potential avenues for therapeutic development. PMID:17535904
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Iftikhar, Fatima; Ali, Yousaf; Ahmad Kiani, Farooq; Fahad Hassan, Syed; Fatima, Tabeer; Khan, Ajmal; Niaz, Basit; Hassan, Abbas; Latif Ansari, Farzana; Rashid, Umer
2017-10-01
In our previous report, we have identified 3,4-dihydropyrimidine scaffold as promising class of urease inhibitor in a structure based virtual screen (SBVS) experiment. In present study, we attempted to optimize the scaffold by varying C-5 substituent. The elongation of the C-5 chain was achieved by the reaction of C-5 ester with hydrazine leading to C-5 carbohydrazides which were further used as building blocks for the synthesis of fifteen new compounds having diverse moieties. A significantly higher in vitro urease inhibitory activity with IC 50 values in submicromolar range was observed for semithiocarbazide derivatives (4a-c, 0.58-0.79µM) and isatin Schiff base derivative 5a (0.23µM). Docking analysis suggests that the synthesized compounds were anchored well in the catalytic site and extending to the entrance of binding pocket and thus restrict the mobility of the flap by interacting with its key amino acid residues. The overall results of urease inhibition have shown that these compounds can be further optimized and developed as lead urease inhibitors. Copyright © 2017 Elsevier Inc. All rights reserved.
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Farrow, Blake; Wong, Michelle; Malette, Jacquie; Lai, Bert; Deyle, Kaycie M; Das, Samir; Nag, Arundhati; Agnew, Heather D; Heath, James R
2015-06-08
Botulinum neurotoxin (BoNT) serotype A is the most lethal known toxin and has an occluded structure, which prevents direct inhibition of its active site before it enters the cytosol. Target-guided synthesis by in situ click chemistry is combined with synthetic epitope targeting to exploit the tertiary structure of the BoNT protein as a landscape for assembling a competitive inhibitor. A substrate-mimicking peptide macrocycle is used as a direct inhibitor of BoNT. An epitope-targeting in situ click screen is utilized to identify a second peptide macrocycle ligand that binds to an epitope that, in the folded BoNT structure, is active-site-adjacent. A second in situ click screen identifies a molecular bridge between the two macrocycles. The resulting divalent inhibitor exhibits an in vitro inhibition constant of 165 pM against the BoNT/A catalytic chain. The inhibitor is carried into cells by the intact holotoxin, and demonstrates protection and rescue of BoNT intoxication in a human neuron model. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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NASA Astrophysics Data System (ADS)
Adhikari, Arijit A.
was applied towards the synthesis of natural products and their analogs. The pyrroloindoline ring system is found in many alkaloids and cyclic peptides which mainly differ in the substitution at the C3a position. To provide rapid access to these natural products a diversity-oriented strategy was established via displacement of C3a-trichloroacetimidate pyrroloindoline. Carbon, oxygen, sulfur and nitrogen nucleophiles were all shown to undergo substitution reactions with these trichloroacetimidates in the presence of a Lewis acid catalyst. In order to demonstrate the utility of this new method it was applied towards the synthesis of arundinine and a formal synthesis of psychotriasine. Current investigations involve the application of this method towards the synthesis of a complex pyrroloindoline natural product kapakahine C and the progress made therein has been discussed. The reactivity of trichloroacetimidates was also investigated for the selective C3-alkylation of 2,3-disubstituted indoles to provide indolenines. Indolenines serve as useful intermediates in the synthesis of many complex alkaloids. Different benzylic and allylic trichloroacetimidates were shown to provide 3,3'-disubstituted indolenines with high yields in the presence of catalytic amounts of Lewis acids. Various substituted indoles were evaluated under these reaction conditions. This methodology was also applied towards the synthesis of the core tetracyclic ring system found in communesin natural products. In addition to the above work, synthesis of small molecule inhibitors of Src Homology 2 Domain-Containing Inositol Phosphatase (SHIP) has also been described. Aberrations in the phosphoinositide 3-kinase (PI3K) cellular signaling pathway can lead to diseased cellular states like cancer. Herein we have reported stereoselective synthesis of two quinoline based small molecule SHIP inhibitors. The lead compounds and their analogs were tested for their activities against SHIP by Malachite green assay
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Luisi, Grazia; Mollica, Adriano; Carradori, Simone; Lenoci, Alessia; De Luca, Anastasia; Caccuri, Anna Maria
2016-12-01
The inhibition of glutathione S-transferase P1-1 (GSTP1-1) is a sound strategy to overcome drug resistance in oncology practice. The nitrobenzoxadiazolyl (NBD) S-conjugate of glutathione and the corresponding γ-oxa-glutamyl isostere (compounds 1 and 5, respectively) have been disclosed as GST inhibitors. The rationale of their design is discussed in juxtaposition to non-peptide NBD thioethers. Synthesis of derivatives 1 and 5 and in vitro evaluation on human GSTP1-1 and M2-2 are reported. Conjugates 1 and 5 were found to be low micromolar inhibitors of both isoforms. Furthermore, they display a threefold reduction in selectivity for GSTM2-2 over the P1-1 isozyme in comparison with the potent non-peptide inhibitor nitrobenzoxadiazolyl-thiohexanol (NBDHEX). Spectroscopic data are congruent with the formation of a stable sigma-complex between GSH and the inhibitors in the protein active site. Conjugate 5 is suitable for in vivo modulation of GST activity in cancer treatment.
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Wodtke, Robert; Hauser, Christoph; Ruiz-Gómez, Gloria; Jäckel, Elisabeth; Bauer, David; Lohse, Martin; Wong, Alan; Pufe, Johanna; Ludwig, Friedrich-Alexander; Fischer, Steffen; Hauser, Sandra; Greif, Dieter; Pisabarro, M Teresa; Pietzsch, Jens; Pietsch, Markus; Löser, Reik
2018-05-24
Transglutaminase 2 (TGase 2)-catalyzed transamidation represents an important post-translational mechanism for protein modification with implications in physiological and pathophysiological conditions, including fibrotic and neoplastic processes. Consequently, this enzyme is considered a promising target for the diagnosis of and therapy for these diseases. In this study, we report on the synthesis and kinetic characterization of N ε -acryloyllysine piperazides as irreversible inhibitors of TGase 2. Systematic structural modifications on 54 new compounds were performed with a major focus on fluorine-bearing substituents due to the potential of such compounds to serve as radiotracer candidates for positron emission tomography. The determined inhibitory activities ranged from 100 to 10 000 M -1 s -1 , which resulted in comprehensive structure-activity relationships. Structure-activity correlations using various substituent parameters accompanied by covalent docking studies provide an advanced understanding of the molecular recognition for this inhibitor class within the active site of TGase 2. Selectivity profiling of selected compounds for other transglutaminases demonstrated an excellent selectivity toward transglutaminase 2. Furthermore, an initial pharmacokinetic profiling of selected inhibitors was performed, including the assessment of potential membrane permeability and liver microsomal stability.
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Berti, Federico; Frecer, Vladimir; Miertus, Stanislav
2014-01-01
Despite the fact that HIV-Protease is an over 20 years old target, computational approaches to rational design of its inhibitors still have a great potential to stimulate the synthesis of new compounds and the discovery of new, potent derivatives, ever capable to overcome the problem of drug resistance. This review deals with successful examples of inhibitors identified by computational approaches, rather than by knowledge-based design. Such methodologies include the development of energy and scoring functions, docking protocols, statistical models, virtual combinatorial chemistry. Computations addressing drug resistance, and the development of related models as the substrate envelope hypothesis are also reviewed. In some cases, the identified structures required the development of synthetic approaches in order to obtain the desired target molecules; several examples are reported.
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Chlamydia spp. development is differentially altered by treatment with the LpxC inhibitor LPC-011.
Cram, Erik D; Rockey, Daniel D; Dolan, Brian P
2017-04-24
Chlamydia species are obligate intracellular bacteria that infect a broad range of mammalian hosts. Members of related genera are pathogens of a variety of vertebrate and invertebrate species. Despite the diversity of Chlamydia, all species contain an outer membrane lipooligosaccharide (LOS) that is comprised of a genus-conserved, and genus-defining, trisaccharide 3-deoxy-D-manno-oct-2-ulosonic acid Kdo region. Recent studies with lipopolysaccharide inhibitors demonstrate that LOS is important for the C. trachomatis developmental cycle during RB- > EB differentiation. Here, we explore the effects of one of these inhibitors, LPC-011, on the developmental cycle of five chlamydial species. Sensitivity to the drug varied in some of the species and was conserved between others. We observed that inhibition of LOS biosynthesis in some chlamydial species induced formation of aberrant reticulate bodies, while in other species, no change was observed to the reticulate body. However, loss of LOS production prevented completion of the chlamydial reproductive cycle in all species tested. In previous studies we found that C. trachomatis and C. caviae infection enhances MHC class I antigen presentation of a model self-peptide. We find that treatment with LPC-011 prevents enhanced host-peptide presentation induced by infection with all chlamydial-species tested. The data demonstrate that LOS synthesis is necessary for production of infectious progeny and inhibition of LOS synthesis induces aberrancy in certain chlamydial species, which has important implications for the use of LOS synthesis inhibitors as potential antibiotics.
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Forcellini, Elsa; Boutin, Sophie; Lefebvre, Carole-Anne; Shayhidin, Elnur Elyar; Boulanger, Marie-Chloé; Rhéaume, Gabrielle; Barbeau, Xavier; Lagüe, Patrick; Mathieu, Patrick; Paquin, Jean-François
2018-03-10
The ecto-nucleotide pyrophosphatase/phosphodiesterase-1 (NPP1) was recently shown to promote mineralization of the aortic valve, hence, its inhibition represents a significant target. A quinazoline-4-piperidine sulfamide compound (QPS1) has been described as a specific and non-competitive inhibitor of NPP1. We report herein the synthesis and in vitro inhibition studies of novel quinazoline-4-piperidine sulfamide analogues using QPS1 as the lead compound. Of the 26 derivatives prepared, four compounds were found to have K i < 105 nM against human NPP1. Copyright © 2018 Elsevier Masson SAS. All rights reserved.
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Kaneko, Toshihiko; Clark, Richard S J; Ohi, Norihito; Kawahara, Tetsuya; Akamatsu, Hiroshi; Ozaki, Fumihiro; Kamada, Atsushi; Okano, Kazuo; Yokohama, Hiromitsu; Muramoto, Kenzo; Ohkuro, Masayoshi; Takenaka, Osamu; Kobayashi, Seiichi
2002-07-01
During a search for novel, orally-active inhibitors of upregulation of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1), we found a new series of 10H-pyrazino[2,3-b][1,4]benzothiazine derivatives to be potent ICAM-1 inhibitors. Of these compounds, N-[1-(10H-Pyrazino[2,3-b][1,4]benzothiazin-8-ylmethyl)piperidin-4-yl]-N',N'-dimethylsulfamide 7p showed the potent oral inhibitory activities against neutrophil migration in a murine interleukin-1 (IL-1) induced paw inflammation model. The synthesis and structure-activity relationships of these amide derivatives are described.
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Salim, Angela A; Rae, James; Fontaine, Frank; Conte, Melissa M; Khalil, Zeinab; Martin, Sally; Parton, Robert G; Capon, Robert J
2010-07-21
A bioassay-guided search for inhibitors of lipid droplet formation in a deep-water southern Australian marine sponge, Spongia (Heterofibria) sp., yielded six new compounds, fatty acids heterofibrins A1 (1) and B1 (4), along with related monolactyl and dilactyl esters, heterofibrins A2 (2), B2 (5), A3 (3) and B3 (6). Heterofibrin structures were assigned on the basis of detailed spectroscopic analysis, with comparison to chiral synthetic model compounds. All heterofibrins possess a diyne-ene moiety, while the monolactyl and dilactyl moiety featured in selected heterofibrins is unprecedented in the natural products literature. SAR by co-metabolite studies on the heterofibrins confirmed them to be non-cytotoxic, with the carboxylic acids 1 and 4 inhibiting lipid droplet formation in A431 fibroblast cell lines. Such inhibitors have potential application in the management of obesity, diabetes and atherosclerosis
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Uehara, Eriko; Hokazono, Hideki; Hida, Mariko; Sasaki, Takako; Yoshioka, Hidekatsu; Matsuo, Noritaka
2017-06-01
The multiple physiological effects of γ-aminobutyric acid (GABA) as a functional food component have been recently reported. We previously reported that GABA upregulated the expression of type I collagen in human dermal fibroblasts (HDFs), and that oral administration of GABA significantly increased skin elasticity. However, details of the regulatory mechanism still remain unknown. In this study, we further examined the effects of GABA on elastin synthesis and elastin fiber formation in HDFs. Real-time PCR indicated that GABA significantly increased the expression of tropoelastin transcript in a dose-dependent manner. Additionally, the expression of fibrillin-1, fibrillin-2, and fibulin-5/DANCE, but not lysyl oxidase and latent transforming factor-β-binding protein 4, were also significantly increased in HDFs. Finally, immunohistochemical analysis confirmed that treatment with GABA dramatically increased the formation of elastic fibers in HDFs. Taken together, our results showed that GABA improves skin elasticity in HDFs by upregulating elastin synthesis and elastin fiber formation.
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Lai, Yu-Chiang; Liu, Yang; Jacobs, Roxane; Rider, Mark H
2012-10-01
PKB (protein kinase B), also known as Akt, is a key component of insulin signalling. Defects in PKB activation lead to insulin resistance and metabolic disorders, whereas PKB overactivation has been linked to tumour growth. Small-molecule PKB inhibitors have thus been developed for cancer treatment, but also represent useful tools to probe the roles of PKB in insulin action. In the present study, we examined the acute effects of two allosteric PKB inhibitors, MK-2206 and Akti 1/2 (Akti) on PKB signalling in incubated rat soleus muscles. We also assessed the effects of the compounds on insulin-stimulated glucose uptake, glycogen and protein synthesis. MK-2206 dose-dependently inhibited insulin-stimulated PKB phosphorylation, PKBβ activity and phosphorylation of PKB downstream targets (including glycogen synthase kinase-3α/β, proline-rich Akt substrate of 40 kDa and Akt substrate of 160 kDa). Insulin-stimulated glucose uptake, glycogen synthesis and glycogen synthase activity were also decreased by MK-2206 in a dose-dependent manner. Incubation with high doses of MK-2206 (10 μM) inhibited insulin-induced p70 ribosomal protein S6 kinase and 4E-BP1 (eukaryotic initiation factor 4E-binding protein-1) phosphorylation associated with increased eEF2 (eukaryotic elongation factor 2) phosphorylation. In contrast, Akti only modestly inhibited insulin-induced PKB and mTOR (mammalian target of rapamycin) signalling, with little or no effect on glucose uptake and protein synthesis. MK-2206, rather than Akti, would thus be the tool of choice for studying the role of PKB in insulin action in skeletal muscle. The results point to a key role for PKB in mediating insulin-stimulated glucose uptake, glycogen synthesis and protein synthesis in skeletal muscle.
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The Potential Role of Formate for Synthesis and Life in Serpentinization Systems
NASA Astrophysics Data System (ADS)
Lang, S. Q.; Frueh-Green, G. L.; Bernasconi, S. M.; Brazelton, W. J.; McGonigle, J. M.
2016-12-01
The high hydrogen concentrations produced during water-rock serpentinization reactions provide abundant thermodynamic energy that can drive the synthesis of organic compounds both biotically and abiotically. We investigated the synthesis of abiotic carbon and the metabolic pathways of the microbial inhabitants of the high energy but low diversity serpentinite-hosted Lost City Hydrothermal Field. High concentrations of the organic acid formate can be attributed to two sources. In some locations formate lacks detectable 14C, demonstrating it was formed abiotically from mantle-derived CO2. In other locations there is an additional modern contribution to the formate pool, potentially indicating active cycling with modern seawater dissolved inorganic carbon by microorganisms. The presence of this carbon source is likely critical for the survival of the subsurface microbial communities that inhabit alkaline serpentinization environments, where inorganic carbon is severely limited. Archaeal lipids produced by the Lost City Methanosarcinales (LCMS) also largely lack 14C, requiring their carbon source to be similarly 14C-free. Metagenomic evidence suggests that the LCMS could use formate for methanogenesis and, altogether, the data suggests that these organisms cannot rely on inorganic carbon as their carbon source and substrate for methanogenesis. Considering the lack of dissolved inorganic carbon in this system, the ability to utilize formate may have been a key evolutionary adaptation for survival in serpentinite-hosted environments. In the Lost City system, the LCMS apparently rely upon an abiotically produced organic carbon source, which may enable the Lost City microbial ecosystem to survive in the absence of photosynthesis or its byproducts.
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Bicarbonate dependency of betaine synthesis in cultured LLC-PK1 cells.
Moeckel, G W; Lien, Y H
1994-03-01
Betaine, one of the major renal organic osmolytes, is synthesized from choline by choline dehydrogenase (EC 1.1.99.1) and betaine-aldehyde dehydrogenase (EC 1.2.1.8) in the kidney. A recent in vitro study has shown that betaine synthesis by renal cortical homogenate is dependent on millimolar amounts of bicarbonate. The present study was aimed to investigate the bicarbonate dependency of betaine formation in cultured LLC-PK1 cells. The data show that betaine formation increases in accordance with a rise in extracellular bicarbonate levels. The measured quantities of [14C]betaine synthesis ranged from 13.4 +/- 1.5 (4.6 mM HCO3-) to 38.0 +/- 1.4 pmol.micrograms protein-1.h-1 (24 mM HCO3-). The carbonic anhydrase inhibitor acetazolamide, added to the incubation medium to block bicarbonate transport, reduced betaine synthesis from choline by 41-49%. We conclude that betaine synthesis in LLC-PK1 cells is dependent on extracellular bicarbonate levels and is reduced by the inhibition of carbonic anhydrase. Because betaine accumulates in renal medulla during antidiuresis, our observations suggest a possible link between acid-base homeostasis and concentration mechanisms in the kidney.
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Frlan, Rok; Kovac, Andreja; Blanot, Didier; Gobec, Stanislav; Pecar, Slavko; Obreza, Ales
2008-01-11
A series of novel N-benzylidenesulfonohydrazide compounds were designed and synthesized as inhibitors of UDP-N-acetylmuramic acid: L-alanine ligase (MurC) and UDP-N-acetylmuramoyl-L-alanine: D-glutamate ligase (MurD) from E. coli, involved in the biosynthesis of bacterial cell-walls. Some compounds possessed inhibitory activity against both enzymes with IC(50) values as low as 30 microM. In addition, a new, one-pot synthesis of amidobenzaldehydes is reported.
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Huang, Huan; McIntosh, Avery L.; Martin, Gregory G.; Petrescu, Anca D.; Landrock, Kerstin K.; Landrock, Danilo; Kier, Ann B.; Schroeder, Friedhelm
2013-01-01
While TOFA (acetyl CoA carboxylase inhibitor) and C75 (fatty acid synthase inhibitor) prevent lipid accumulation by inhibiting fatty acid synthesis, the mechanism of action is not simply accounted for by inhibition of the enzymes alone. Liver fatty acid binding protein (L-FABP), a mediator of long chain fatty acid signaling to peroxisome proliferator-activated receptor-α (PPARα) in the nucleus, was found to bind TOFA and its activated CoA thioester, TOFyl-CoA, with high affinity while binding C75 and C75-CoA with lower affinity. Binding of TOFA and C75-CoA significantly altered L-FABP secondary structure. High (20 mM) but not physiological (6 mM) glucose conferred on both TOFA and C75 the ability to induce PPARα transcription of the fatty acid β-oxidative enzymes CPT1A, CPT2, and ACOX1 in cultured primary hepatocytes from wild-type (WT) mice. However, L-FABP gene ablation abolished the effects of TOFA and C75 in the context of high glucose. These effects were not associated with an increased cellular level of unesterified fatty acids but rather by increased intracellular glucose. These findings suggested that L-FABP may function as an intracellular fatty acid synthesis inhibitor binding protein facilitating TOFA and C75-mediated induction of PPARα in the context of high glucose at levels similar to those in uncontrolled diabetes. PMID:23533380
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Tu, Ling-Hsien; Young, Lydia M; Wong, Amy G; Ashcroft, Alison E; Radford, Sheena E; Raleigh, Daniel P
2015-01-27
The process of amyloid formation by the normally soluble hormone islet amyloid polypeptide (IAPP) contributes to β-cell death in type 2 diabetes and in islet transplants. There are no clinically approved inhibitors of islet amyloidosis, and the mode of action of existing inhibitors is not well-understood. Resveratrol, a natural polyphenol, has been reported to inhibit amyloid formation by IAPP and by the Alzheimer's disease Aβ peptide. The mechanism of action of this compound is not known, nor is its mode of interaction with IAPP. In this study, we use a series of IAPP variants to examine possible interactions between resveratrol and IAPP. Fluorescence assays, transmission electron microscopy, and mass spectrometry demonstrate that resveratrol is much less effective as an inhibitor of IAPP amyloid formation than the polyphenol (-)-epigallocatechin 3-gallate (EGCG) and, unlike EGCG, does not significantly disaggregate preformed IAPP amyloid fibrils. Resveratrol is also shown to interfere with thioflavin-T assays. His-18 mutants, a truncation mutant, mutants of each of the aromatic residues, and mutants of Arg-11 of IAPP were examined. Mutation of His to Gln or Leu weakens the ability of resveratrol to inhibit amyloid formation by IAPP, as do mutations of Arg-11, Phe-15, or Tyr-37 to Leu, and truncation to form the variant Ac 8-37-IAPP, which removes the first seven residues to eliminate Lys-1 and the N-terminal amino group. In contrast, replacement of Phe-23 with Leu has a smaller effect. The data highlight Phe-15, His-18, and Tyr-37 as being important for IAPP-resveratrol interactions and are consistent with a potential role of the N-terminus and Arg-11 in polypeptide-resveratrol interactions.
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Synthesis and evaluation of 3,4-dihydropyrimidin-2(1H)-ones as sodium iodide symporter inhibitors.
Lacotte, Pierre; Puente, Celine; Ambroise, Yves
2013-01-01
The sodium iodide symporter (NIS) is responsible for the accumulation of iodide in the thyroid gland. This transport process is involved in numerous thyroid dysfunctions and is the basis for human contamination in the case of exposure to radioactive iodine species. 4-Aryl-3,4-dihydropyrimidin-2(1H)-ones were recently discovered by high-throughput screening as the first NIS inhibitors. Described herein are the synthesis and evaluation of 115 derivatives with structural modifications at five key positions on the pyrimidone core. This study provides extensive structure-activity relationships for this new class of inhibitors that will serve as a basis for further development of compounds with in vivo efficacy and adequate pharmacokinetic properties. In addition, the SAR investigation provided a more potent compound, which exhibits an IC(50) value of 3.2 nM in a rat thyroid cell line (FRTL5). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Sova, Matej; Kovac, Andreja; Turk, Samo; Hrast, Martina; Blanot, Didier; Gobec, Stanislav
2009-12-01
Enzymes involved in the biosynthesis of bacterial peptidoglycan represent important targets for development of new antibacterial drugs. Among them, Mur ligases (MurC to MurF) catalyze the formation of the final cytoplasmic precursor UDP-N-acetylmuramyl-pentapeptide from UDP-N-acetylmuramic acid. We present the design, synthesis and biological evaluation of a series of phosphorylated hydroxyethylamines as new type of small-molecule inhibitors of Mur ligases. We show that the phosphate group attached to the hydroxyl moiety of the hydroxyethylamine core is essential for good inhibitory activity. The IC(50) values of these inhibitors were in the micromolar range, which makes them a promising starting point for the development of multiple inhibitors of Mur ligases as potential antibacterial agents. In addition, 1-(4-methoxyphenylsulfonamido)-3-morpholinopropan-2-yl dihydrogen phosphate 7a was discovered as one of the best inhibitors of MurE described so far.
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The NADPH oxidase inhibitor apocynin induces nitric oxide synthesis via oxidative stress
DOE Office of Scientific and Technical Information (OSTI.GOV)
Riganti, Chiara; Costamagna, Costanzo; Doublier, Sophie
We have recently shown that apocynin elicits an oxidative stress in N11 mouse glial cells and other cell types. Here we report that apocynin increased the accumulation of nitrite, the stable derivative of nitric oxide (NO), in the extracellular medium of N11 cell cultures, and the NO synthase (NOS) activity in cell lysates. The increased synthesis of NO was associated with increased expression of inducible NOS (iNOS) mRNA, increased nuclear translocation of the redox-sensitive transcription factor NF-{kappa}B and decreased intracellular level of its inhibitor IkB{alpha}. These effects, accompanied by increased production of H{sub 2}O{sub 2}, were very similar to thosemore » observed after incubation with bacterial lipopolysaccharide (LPS) and were inhibited by catalase. These results suggest that apocynin, similarly to LPS, induces increased NO synthesis by eliciting a generation of reactive oxygen species (ROS), which in turn causes NF-{kappa}B activation and increased expression of iNOS. Therefore, the increased bioavailability of NO reported in the literature after in vivo or in vitro treatments with apocynin might depend, at least partly, on the drug-elicited induction of iNOS, and not only on the inhibition of NADPH oxidase and the subsequent decreased scavenging of NO by oxidase-derived ROS, as it is often supposed.« less
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Precursor soot synthesis of fullerenes and nanotubes without formation of carbonaceous soot
Reilly, Peter T. A.
2007-03-20
The present invention is a method for the synthesis of fullerenes and/or nanotubes from precursor soot without the formation of carbonaceous soot. The method comprises the pyrolysis of a hydrocarbon fuel source by heating the fuel source at a sufficient temperature to transform the fuel source to a condensed hydrocarbon. The condensed hydrocarbon is a reaction medium comprising precursor soot wherein hydrogen exchange occurs within the reaction medium to form reactive radicals which cause continuous rearrangement of the carbon skeletal structure of the condensed hydrocarbon. Then, inducing dehydrogenation of the precursor soot to form fullerenes and/or nanotubes free from the formation of carbonaceous soot by continued heating at the sufficient temperature and by regulating the carbon to hydrogen ratio within the reaction medium. The dehydrogenation process produces hydrogen gas as a by-product. The method of the present invention in another embodiment is also a continuous synthesis process having a continuous supply of the fuel source. The method of the present invention can also be a continuous cyclic synthesis process wherein the reaction medium is fed back into the system as a fuel source after extraction of the fullerenes and/or nanotube products. The method of the present invention is also a method for producing precursor soot in bulk quantity, then forming fullerenes and/or nanotubes from the precursor bulk.
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Bhatti, Huma Aslam; Khatoon, Memoona; Al-Rashida, Mariya; Bano, Huma; Iqbal, Nafees; Zaib-Un-Nisa; Yousuf, Sammer; Khan, Khalid Mohammed; Hameed, Abdul; Iqbal, Jamshed
2017-04-01
Owing to the biological importance of cyclic sulfonamides (sultams), herein we report a new, facile and cost-effective method for the synthesis of sultams that makes use of a reaction between dansyl amide and easily accessible benzaldehydes under mildly acidic conditions. All compounds were obtained in good yields (69-96%). Consequently a series of cyclic sulfonamides (7a-7n) was synthesized and characterized using FTIR, MS and NMR spectroscopy, crystal structure of compound 7b has also been determined. All compounds were evaluated for their potential to inhibit alkaline phosphatase (bTNAP and bIAP). All compounds were found to be excellent inhibitors of bTNAP with IC 50 values in lower micro-molar range (0.11-6.63μM). Most of the compounds were selective inhibitors of bTNAP over bIAP. Only six compounds were found to be active against bIAP (IC 50 values in the range 0.38-3.48μM). Molecular docking studies were carried out to identify and rationalize the structural elements necessary for efficient AP inhibition. Copyright © 2017 Elsevier Inc. All rights reserved.
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Dziedzic, Pawel; Cisneros, José A; Robertson, Michael J; Hare, Alissa A; Danford, Nadia E; Baxter, Richard H G; Jorgensen, William L
2015-03-04
Optimization is reported for biaryltriazoles as inhibitors of the tautomerase activity of human macrophage migration inhibitory factor (MIF), a proinflammatory cytokine associated with numerous inflammatory diseases and cancer. A combined approach was taken featuring organic synthesis, enzymatic assaying, crystallography, and modeling including free-energy perturbation (FEP) calculations. X-ray crystal structures for 3a and 3b bound to MIF are reported and provided a basis for the modeling efforts. The accommodation of the inhibitors in the binding site is striking with multiple hydrogen bonds and aryl-aryl interactions. Additional modeling encouraged pursuit of 5-phenoxyquinolinyl analogues, which led to the very potent compound 3s. Activity was further enhanced by addition of a fluorine atom adjacent to the phenolic hydroxyl group as in 3w, 3z, 3aa, and 3bb to strengthen a key hydrogen bond. It is also shown that physical properties of the compounds can be modulated by variation of solvent-exposed substituents. Several of the compounds are likely the most potent known MIF tautomerase inhibitors; the most active ones are more than 1000-fold more active than the well-studied (R)-ISO-1 and more than 200-fold more active than the chromen-4-one Orita-13.
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Dziedzic, Pawel; Cisneros, José A.; Robertson, Michael J.; ...
2015-02-20
Optimization is reported for biaryltriazoles as inhibitors of the tautomerase activity of human macrophage migration inhibitory factor (MIF), a proinflammatory cytokine associated with numerous inflammatory diseases and cancer. A combined approach was taken featuring organic synthesis, enzymatic assaying, crystallography, and modeling including free-energy perturbation (FEP) calculations. X-ray crystal structures for 3a and 3b bound to MIF are reported and provided a basis for the modeling efforts. The accommodation of the inhibitors in the binding site is striking with multiple hydrogen bonds and aryl–aryl interactions. Additional modeling encouraged pursuit of 5-phenoxyquinolinyl analogues, which led to the very potent compound 3s. Activitymore » was further enhanced by addition of a fluorine atom adjacent to the phenolic hydroxyl group as in 3w, 3z, 3aa, and 3bb to strengthen a key hydrogen bond. We also show that physical properties of the compounds can be modulated by variation of solvent-exposed substituents. Several of the compounds are likely the most potent known MIF tautomerase inhibitors; the most active ones are more than 1000-fold more active than the well-studied (R)-ISO-1 and more than 200-fold more active than the chromen-4-one Orita-13.« less
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Yngve, Ulrika; Söderman, Peter; Svensson, Mats; Rosqvist, Susanne; Arvidsson, Per I
2012-11-01
In this study, we explored the effect of bioisostere replacement in a series of glycogen synthase kinase 3 (GSK3) inhibitors based on the imidazopyridine core. The synthesis and biological evaluation of a number of novel sulfonamide, 1,2,4-oxadiazole, and thiazole derivates as amide bioisosteres, as well as a computational rationalization of the obtained results are reported. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.
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Yang, You; Li, Yao; Yu, Biao
2009-09-02
TMG-chitotriomycin, a potent and selective inhibitor of the beta-N-acetylglucosaminidases that possesses an unique N,N,N-trimethyl-d-glucosamine (TMG) residue, is revised to be the TMG-beta-(1-->4)-chitotriose instead of the originally proposed alpha-anomer via its total synthesis, for which a highly convergent approach was developed in which the sterically demanding (1-->4)-glycosidic linkages are efficiently constructed by the Au(I)-catalyzed glycosylation protocol with glycosyl o-hexynylbenzoates as donors.
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New MKLP-2 inhibitors in the paprotrain series: Design, synthesis and biological evaluations.
Labrière, Christophe; Talapatra, Sandeep K; Thoret, Sylviane; Bougeret, Cécile; Kozielski, Frank; Guillou, Catherine
2016-02-15
Members of the kinesin superfamily are involved in key functions during intracellular transport and cell division. Their involvement in cell division makes certain kinesins potential targets for drug development in cancer chemotherapy. The two most advanced kinesin targets are Eg5 and CENP-E with inhibitors in clinical trials. Other mitotic kinesins are also being investigated for their potential as prospective drug targets. One recently identified novel potential cancer therapeutic target is the Mitotic kinesin-like protein 2 (MKLP-2), a member of the kinesin-6 family, which plays an essential role during cytokinesis. Previous studies have shown that inhibition of MKLP-2 leads to binucleated cells due to failure of cytokinesis. We have previously identified compound 1 (paprotrain) as the first selective inhibitor of MKLP-2. Herein we describe the synthesis and biological evaluation of new analogs of 1. Our structure-activity relationship (SAR) study reveals the key chemical elements in the paprotrain family necessary for MKLP-2 inhibition. We have successfully identified one MKLP-2 inhibitor 9a that is more potent than paprotrain. In addition, in vitro analysis of a panel of kinesins revealed that this compound is selective for MKLP-2 compared to other kinesins tested and also does not have an effect on microtubule dynamics. Upon testing in different cancer cell lines, we find that the more potent paprotrain analog is also more active than paprotrain in 10 different cancer cell lines. Increased selectivity and higher potency is therefore a step forward toward establishing MKLP-2 as a potential cancer drug target. Copyright © 2015 Elsevier Ltd. All rights reserved.
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Wang, Yali; Sun, Yang; Guo, Yueyan; Wang, Zechen; Huang, Ling; Li, Xingshu
2016-01-01
Because of the complexity of Alzheimer's disease (AD), the multi-target-directed ligand (MTDL) strategy is expected to provide superior effects for the treatment of AD, instead of the classic one-drug-one-target strategy. In this context, we focused on the design, synthesis and evaluation of homoisoflavonoid derivatives as dual acetyl cholinesterase (AChE) and monoamine oxidase (MAO-B) inhibitors. Among all the synthesized compounds, compound 10 provided a desired balance of AChE and hMAO-B inhibition activities, with IC50 value of 3.94 and 3.44 μM, respectively. Further studies revealed that compound 10 was a mixed-type inhibitor of AChE and an irreversible inhibitor of hMAO-B, which was also confirmed by molecular modeling studies. Taken together, the data indicated that 10 was a promising dual functional agent for the treatment of AD.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Ghosh, Arun K.; Martyr, Cuthbert D.; Osswald, Heather L.
Structure-based design, synthesis, and biological evaluation of a series of very potent HIV-1 protease inhibitors are described. In an effort to improve backbone ligand–binding site interactions, we have incorporated basic-amines at the C4 position of the bis-tetrahydrofuran (bis-THF) ring. We speculated that these substituents would make hydrogen bonding interactions in the flap region of HIV-1 protease. Synthesis of these inhibitors was performed diastereoselectively. A number of inhibitors displayed very potent enzyme inhibitory and antiviral activity. Inhibitors 25f, 25i, and 25j were evaluated against a number of highly-PI-resistant HIV-1 strains, and they exhibited improved antiviral activity over darunavir. Two high resolutionmore » X-ray structures of 25f- and 25g-bound HIV-1 protease revealed unique hydrogen bonding interactions with the backbone carbonyl group of Gly48 as well as with the backbone NH of Gly48 in the flap region of the enzyme active site. These ligand–binding site interactions are possibly responsible for their potent activity.« less
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Beilby, J P
1983-05-01
The incorporation of isotopically labelled precursors, [1-14C]leucine, [2-14C]uracil and [1-14C]acetate, by germinating spores of the vesicular-arbuscular mycorrhizal fungus Glomus caledonium was investigated after prior incubation with several metabolic inhibitors. Inhibition of isotope incorporation was greatest with ethidium bromide and cycloheximide and least with chloramphenicol and actinomycin D. The incorporation of [1-14C]leucine into protein was reduced by 92% within 60 min of incubation in either ethidium bromide at 5 micrograms/mL or cycloheximide at 100 micrograms/mL. For these studies time zero was coincident with dry quiescent spores being first wet. Lipid synthesis during germination of the spores was detected at 120 min by following the incorporation of [1-14C]acetate. At 51 h, incorporation was greater in the triacylglycerides and diacylglycerides than in the free sterols, phospholipids, or free fatty acid. Spores exposed to cycloheximide for 60 min after imbibition showed very little phospholipid synthesis and no free fatty acid synthesis. The synthesis of RNA after spore imbibition is also discussed.
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Potts, Barbara C.; Lam, Kin S.
2010-01-01
The salinosporamides are potent proteasome inhibitors among which the parent marine-derived natural product salinosporamide A (marizomib; NPI-0052; 1) is currently in clinical trials for the treatment of various cancers. Methods to generate this class of compounds include fermentation and natural products chemistry, precursor-directed biosynthesis, mutasynthesis, semi-synthesis, and total synthesis. The end products range from biochemical tools for probing mechanism of action to clinical trials materials; in turn, the considerable efforts to produce the target molecules have expanded the technologies used to generate them. Here, the full complement of methods is reviewed, reflecting remarkable contributions from scientists of various disciplines over a period of 7 years since the first publication of the structure of 1. PMID:20479958
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Design and synthesis of aminocoumarin derivatives as DPP-IV inhibitors and anticancer agents.
Soni, Rina; Soman, Shubhangi S
2018-09-01
DPP-IV "a moonlighting protein" has immerged as promising pathway to control Type 2 diabetes as well as found to play key role in earlier stages of cancer. Here we have reported design, synthesis and applications of aminocoumarin derivatives as DPP-IV inhibitors. Compounds have been synthesized and studied for their DPP-IV inhibition activity. Three compounds have shown moderate inhibition at 100 µM concentration. All compounds were also screened for their anticancer activity against A549 (Lung cancer cell line), MCF-7 (Breast cancer cell line) using MTT assay. One of the compounds has shown very good anticancer activity with IC 50 value 24 ± 0.1 nM against A549 cell line. Copyright © 2018 Elsevier Inc. All rights reserved.
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Xing, Lin; Chouvenc, Thomas; Su, Nan-Yao
2014-04-01
This study describes the behavioral and histological changes of the molting process in Coptotermes formosanus Shiraki caused by the chitin synthesis inhibitor noviflumuron. Termites exposed to noviflumuron initiated ecdysis as untreated individuals did; however, peristalsis contractions were weak and the expansion of the dorsal breach of the exoskeleton did not occur. Treated termites could not complete their molting process and died after the initiation of the ecdysis. Histological observations showed that the process of voiding the gut protozoa during premolting was not affected by the noviflumuron treatment. However, the formation of the new cuticle was disrupted resulting in the loss of integrity of the cuticle. The alteration of the cuticle was visible in the gizzard (foregut), the thoracic pleurons, and most of the exoskeleton. Muscles were partially able to reattach to the incompletely formed new cuticle, and muscle contractions resulted in tearing off the cuticle. Because the integrity of the newly formed cuticle was compromised by the noviflumuron treatment, we concluded that termites' death was caused primarily by the loss of hemolymph as a result of the damage done by the muscle contractions on the exoskeleton during the peristalsis. As the physiological homeostasis was disrupted, termites were too weak to shed their old cuticle, ultimately resulting in termite dying during the molting process.
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Synthesis of Barbiturate-Based Methionine Aminopeptidase-1 Inhibitors
Haldar, Manas K.; Scott, Michael D.; Sule, Nitesh; Srivastava, D. K.; Mallik, Sanku
2008-01-01
The syntheses of a new class of barbiturate-based inhibitors for human and E. Coli Methionine Aminopeptidase -1 (MetAP-1) are described. Some of the synthesized inhibitors show selective inhibition of the human enzyme with high potency. PMID:18343108
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Filone, Claire Marie; Hodges, Erin N.; Honeyman, Brian; Bushkin, G. Guy; Boyd, Karla; Platt, Andrew; Ni, Feng; Strom, Kyle; Hensley, Lisa; Snyder, John K.; Connor, John H.
2013-01-01
There are no approved therapeutics for the most deadly nonsegmented negative-strand (NNS) RNA viruses, including Ebola (EBOV). To identify new chemical scaffolds for development of broad-spectrum antivirals, we undertook a prototype-based lead identification screen. Using the prototype NNS virus, vesicular stomatitis virus (VSV), multiple inhibitory compounds were identified. Three compounds were investigated for broad-spectrum activity, and inhibited EBOV infection. The most potent, CMLDBU3402, was selected for further study. CMLDBU3402 did not show significant activity against segmented negative-strand RNA viruses suggesting proscribed broad-spectrum activity. Mechanistic analysis indicated that CMLDBU3402 blocked VSV viral RNA synthesis and inhibited EBOV RNA transcription, demonstrating a consistent mechanism of action against genetically distinct viruses. The identification of this chemical backbone as a broad-spectrum inhibitor of viral RNA synthesis offers significant potential for the development of new therapies for highly pathogenic viruses. PMID:23521799
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Frlan, Rok; Kovač, Andreja; Blanot, Didier; Gobec, Stanislav; Pečar, Slavko; Obreza, Aleš
2011-06-01
Mur ligases are essential enzymes involved in the cytoplasmic steps of peptidoglycan synthesis which remain attractive, yet unexploited targets. In order to develop new antibacterial agents, we have designed a series of new MurC and MurD inhibitors bearing amino acid sulfonohydrazide moiety. The L-Leu series of this class displayed the highest enzyme inhibition with IC50 in the concentration range between 100 and 500 µM, with L-Thr, L-Pro and L-Ala derivatives being inactive. The most promising compound of the series also expressed weak antibacterial activity against S. aureus with MIC = 128 µg/mL.
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Demarcus, M; Ganadu, M L; Mura, G M; Porcheddu, A; Quaranta, L; Reginato, G; Taddei, M
2001-02-09
Different dipeptide analogues containing an oxirane ring in the place of the peptidic bond were prepared starting from naturally occurring amino acids. N-Fmoc-amino aldehydes were transformed into the corresponding methoxyvinyl derivatives through a Wittig reaction, and the addition of PhSeCl gave a series of different alpha-phenylselenyl aldehydes. Mukajiama reaction with silylketene acetals gave an intermediate product that was finally transformed into the desired oxiranyl peptidomimetics. Following this strategy we were able to control three new contiguous stereocenters starting from the enantiomerically pure amino acid. The dipeptide analogues could be used in SPPS on a SASRIN resin as the final epoxides were relatively unstable under acidic conditions. Moreover the synthesis of the single dipeptide mimetics was carried out on solid phase to generate a small library of epoxy peptidomimetics. Some of the products prepared in this work resulted as time-dependent reversible inhibitors of cysteine protease.
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Chowdhury, S F; Villamor, V B; Guerrero, R H; Leal, I; Brun, R; Croft, S L; Goodman, J M; Maes, L; Ruiz-Perez, L M; Pacanowska, D G; Gilbert, I H
1999-10-21
This paper concerns the design, synthesis, and evaluation of inhibitors of leishmanial and trypanosomal dihydrofolate reductase. Initially study was made of the structures of the leishmanial and human enzyme active sites to see if there were significant differences which could be exploited for selective drug design. Then a series of compounds were synthesized based on 5-benzyl-2, 4-diaminopyrimidines. These compounds were assayed against the protozoan and human enzymes and showed selectivity for the protozoan enzymes. The structural data was then used to rationalize the enzyme assay data. Compounds were also tested against the clinically relevant forms of the intact parasite. Activity was seen against the trypanosomes for a number of compounds. The compounds were in general less active against Leishmania. This latter result may be due to uptake problems. Two of the compounds also showed some in vivo activity in a model of African trypanosomiasis.
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Huang, Huan; McIntosh, Avery L; Martin, Gregory G; Petrescu, Anca D; Landrock, Kerstin K; Landrock, Danilo; Kier, Ann B; Schroeder, Friedhelm
2013-01-01
While TOFA (acetyl CoA carboxylase inhibitor) and C75 (fatty acid synthase inhibitor) prevent lipid accumulation by inhibiting fatty acid synthesis, the mechanism of action is not simply accounted for by inhibition of the enzymes alone. Liver fatty acid binding protein (L-FABP), a mediator of long chain fatty acid signaling to peroxisome proliferator-activated receptor- α (PPAR α ) in the nucleus, was found to bind TOFA and its activated CoA thioester, TOFyl-CoA, with high affinity while binding C75 and C75-CoA with lower affinity. Binding of TOFA and C75-CoA significantly altered L-FABP secondary structure. High (20 mM) but not physiological (6 mM) glucose conferred on both TOFA and C75 the ability to induce PPAR α transcription of the fatty acid β -oxidative enzymes CPT1A, CPT2, and ACOX1 in cultured primary hepatocytes from wild-type (WT) mice. However, L-FABP gene ablation abolished the effects of TOFA and C75 in the context of high glucose. These effects were not associated with an increased cellular level of unesterified fatty acids but rather by increased intracellular glucose. These findings suggested that L-FABP may function as an intracellular fatty acid synthesis inhibitor binding protein facilitating TOFA and C75-mediated induction of PPAR α in the context of high glucose at levels similar to those in uncontrolled diabetes.
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Effect of inhibitors of prostaglandin synthesis on gonadotropin release in the rat.
Ojeda, S R; Harms, P G; McCann, S M
1975-10-01
To study the effect of blockade of prostaglandin (PG) synthesis on gonadotropin release in the rat, inhibitors of PG synthesis were injected by various routes in various experimental conditions. The injection of 5-, 8-, 11-, 14-eicosatetraynoic acid (TYA) into the third ventricle (3rd V) significantly decreased plasma LH of ovariectomized (OVX) rats 1, 2, and 4 h following its injection; however, TYA failed to alter plasma LH in OVX rats when administered as a single sc injection and also failed to prevent the post-castration rise in plasma LH when administered sc once daily for 4 days to short-term OVX rats. None of these treatments altered plasma FSH concentrations. Indomethacin (Id) injected into the 3rd V or implanted into the medial basal hypothalamus (MBH) of OVX rats depressed plasma LH 1--6 h later. This effect was no longer observed 24--72 h following its implantation in the MBH. When different doses of Id were administered as single sc injections to OVX rats, plasma LH titers were depressed 24--32 h later, whereas plasma FSH remained either unaltered or was slightly increased. Similarly, the post-castration rise of plasma LH but not that of FSH in male rats was suppressed by a single sc injection of Id given 6 h before orchidectomy. Id administered acutely iv failed to modify the pulsatile release of LH in OVX rats, but it effectively inhibited this release when injected sc 20--30 h before the initiation of blood collection. Moreover, Id blocked the progesterone-induced LH and FSH release in OVX estrogen-primed rats when given sc 24 h before progesterone, but not when it was injected either sc or iv shortly (2 h) before or shortly after (1--3 h) progesterone treatment. Rats treated with Id showed a decrease in BW 24--32 h afters its sc injection. However, the effects of Id on LH release could not be explained by lack of food intake since fasted controls showed LH titers similar to fed rats. Id did not significantly inhibit the LH release in response to
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Faul, Margaret; Larsen, Rob; Levinson, Adam; Tedrow, Jason; Vounatsos, Filisaty
2013-02-15
Aldehyde-bisulfite adducts dervied from unstable parent aldehydes were reductively alkylated in a direct fashion with a variety of amines. This approach features the use of 2-picoline borane as the reducing agent and a protic solvent for the reaction media and has been successfully applied to the synthesis of a DPP-IV inhibitor and a variety of other amines.
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Larkin, Emily; Hager, Christopher; Chandra, Jyotsna; Mukherjee, Pranab K; Retuerto, Mauricio; Salem, Iman; Long, Lisa; Isham, Nancy; Kovanda, Laura; Borroto-Esoda, Katyna; Wring, Steve; Angulo, David; Ghannoum, Mahmoud
2017-05-01
Candida auris , a new multidrug-resistant Candida spp. which is associated with invasive infection and high rates of mortality, has recently emerged. Here, we determined the virulence factors (germination, adherence, biofilm formation, phospholipase and proteinase production) of 16 C. auris isolates and their susceptibilities to 11 drugs belonging to different antifungal classes, including a novel orally bioavailable 1,3-β-d-glucan synthesis inhibitor (SCY-078). We also examined the effect of SCY-078 on the growth, ultrastructure, and biofilm-forming abilities of C. auris Our data showed that while the tested strains did not germinate, they did produce phospholipase and proteinase in a strain-dependent manner and had a significantly reduced ability to adhere and form biofilms compared to that of Candida albicans ( P = 0.01). C. auris isolates demonstrated reduced susceptibility to fluconazole and amphotericin B, while, in general, they were susceptible to the remaining drugs tested. SCY-078 had an MIC 90 of 1 mg/liter against C. auris and caused complete inhibition of the growth of C. auris and C. albicans Scanning electron microscopy analysis showed that SCY-078 interrupted C. auris cell division, with the organism forming abnormal fused fungal cells. Additionally, SCY-078 possessed potent antibiofilm activity, wherein treated biofilms demonstrated significantly reduced metabolic activity and a significantly reduced thickness compared to the untreated control ( P < 0.05 for both comparisons). Our study shows that C. auris expresses several virulence determinants (albeit to a lesser extent than C. albicans ) and is resistant to fluconazole and amphotericin B. SCY-078, the new orally bioavailable antifungal, had potent antifungal/antibiofilm activity against C. auris , indicating that further evaluation of this antifungal is warranted. Copyright © 2017 Larkin et al.
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Soraphen A, an inhibitor of acetyl CoA carboxylase activity, interferes with fatty acid elongation
Jump, Donald B.; Torres-Gonzalez, Moises; Olson, L. Karl
2010-01-01
Acetyl CoA carboxylase (ACC1 & ACC2) generates malonyl CoA, a substrate for de novo lipogenesis (DNL) and an inhibitor of mitochondrial fatty acid β-oxidation (FAO). Malonyl CoA is also a substrate for microsomal fatty acid elongation, an important pathway for saturated (SFA), mono- (MUFA) and polyunsaturated fatty acid (PUFA) synthesis. Despite the interest in ACC as a target for obesity and cancer therapy, little attention has been given to the role ACC plays in long chain fatty acid synthesis. This report examines the effect of pharmacological inhibition of ACC on DNL & palmitate (16:0) and linoleate (18:2,n-6) metabolism in HepG2 and LnCap cells. The ACC inhibitor, soraphen A, lowers cellular malonyl CoA, attenuates DNL and the formation of fatty acid elongation products derived from exogenous fatty acids, i.e., 16:0 & 18:2,n-6; IC50 ~ 5 nM. Elevated expression of fatty acid elongases (Elovl5, Elovl6) or desaturases (FADS1, FADS2) failed to override the soraphen A effect on SFA, MUFA or PUFA synthesis. Inhibition of fatty acid elongation leads to the accumulation of 16- and 18-carbon unsaturated fatty acids derived from 16:0 and 18:2,n-6, respectively. Pharmacological inhibition of ACC activity will not only attenuate DNL and induce FAO, but will also attenuate the synthesis of very long chain saturated, mono- and polyunsaturated fatty acids. PMID:21184748
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Rutenber, E E; McPhee, F; Kaplan, A P; Gallion, S L; Hogan, J C; Craik, C S; Stroud, R M
1996-09-01
The essential role of HIV-1 protease (HIV-1 PR) in the viral life cycle makes it an attractive target for the development of substrate-based inhibitors that may find efficacy as anti-AIDS drugs. However, resistance has arisen to potent peptidomimetic drugs necessitating the further development of novel chemical backbones for diversity based chemistry focused on probing the active site for inhibitor interactions and binding modes that evade protease resistance. AQ148 is a potent inhibitor of HIV-1 PR and represents a new class of transition state analogues incorporating an aminimide peptide isostere. A 3-D crystallographic structure of AQ148, a tetrapeptide isostere, has been determined in complex with its target HIV-1 PR to a resolution of 2.5 A and used to evaluate the specific structural determinants of AQ148 potency and to correlate structure-activity relationships within the class of related compounds. AQ148 is a competitive inhibitor of HIV-1 PR with a Ki value of 137 nM. Twenty-nine derivatives have been synthesized and chemical modifications have been made at the P1, P2, P1', and P2' sites. The atomic resolution structure of AQ148 bound to HIV-1 PR reveals both an inhibitor binding mode that closely resembles that of other peptidomimetic inhibitors and specific protein/inhibitor interactions that correlate with structure-activity relationships. The structure provides the basis for the design, synthesis and evaluation of the next generation of hydroxyethyl aminimide inhibitors. The aminimide peptide isostere is a scaffold with favorable biological properties well suited to both the combinatorial methods of peptidomimesis and the rational design of potent and specific substrate-based analogues.
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NASA Astrophysics Data System (ADS)
Nandiyanto, Asep Bayu Dani
2016-02-01
When synthesizing particles using a liquid-phase synthesis method, reactant components show interaction with the reaction system itself. However, current reports described successful synthesis of material with only partial information on the component-component interaction and possible self-assembly mechanism occurring during the material synthesis process. Here, self-assembly concepts in the formation of nanostructured particles are presented. Influences of self-assembly parameters (i.e., surface charge, size, and concentration of components involving the reaction) on self-organized material fabrication are described. Because understanding the interaction of the component provides significant information in regard to practical uses, this report can be relevant to further material development and fabrication.
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Gooyit, Major; Lee, Mijoon; Hesek, Dusan; Boggess, Bill; Oliver, Allen G; Fridman, Rafael; Mobashery, Shahriar; Chang, Mayland
2009-12-01
Gelatinases (MMP-2 and MMP-9) have been implicated in a number of pathological conditions, including cancer and cardiovascular disease. Hence, small molecule inhibitors of these enzymes are highly sought for use as potential therapeutic agents. 2-(4-Phenoxyphenylsulfonylmethyl)thiirane (SB-3CT) has previously been demonstrated to be a potent and selective inhibitor of gelatinases, however, it is rapidly metabolized because of oxidation at the para position of the phenoxy ring and at the alpha-position to the sulfonyl group. alpha-Methyl variants of SB-3CT were conceived to improve metabolic stability and as mechanistic probes. We describe herein the synthesis and evaluation of these structural variants as potent inhibitors of gelatinases. Two (compounds 5b and 5d) among the four synthetic stereoisomers were found to exhibit slow-binding inhibition of gelatinases and MMP-14 (MT1-MMP), which is a hallmark of the mechanism of this class of inhibitors. The ability of these compounds to inhibit MMP-2, MMP-9, and MMP-14 could target cancer tissues more effectively. Metabolism of the newly synthesized inhibitors showed that both oxidation at the alpha-position to the sulfonyl group and oxidation at the para position of the terminal phenyl ring were prevented. Instead oxidation on the thiirane sulfur is the only biotransformation pathway observed for these gelatinase inhibitors.
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Bagley, Mark C; Davis, Terence; Rokicki, Michal J; Widdowson, Caroline S; Kipling, David
2010-02-01
UR-13756 is a potent and selective p38 mitogen-activated protein kinase (MAPK) inhibitor, reported to have good bioavailability and pharmacokinetic properties and, thus, is of potential use in the treatment of accelerated aging in Werner syndrome. Irradiation of 2-chloroacrylonitrile and methylhydrazine in ethanol at 100 °C gives 1-methyl-3-aminopyrazole, which reacts with 4-fluorobenzaldehyde and a ketone, obtained by Claisen condensation of 4-picoline, in a Hantzsch-type 3-component hereocyclocondensation, to give the pyrazolopyridine UR-13756. UR-13756 shows p38 MAPK inhibitory activity in human telomerase reverse transcriptase-immortalized HCA2 dermal fibroblasts, with an IC(50) of 80 nm, as shown by ELISA, is 100% efficacious for up to 24 h at 1.0 μm and displays excellent kinase selectivity over the related stress-activated c-Jun kinases. In addition, UR-13756 is an effective p38 inhibitor at 1.0 μm in Werner syndrome cells, as shown by immunoblot. The convergent synthesis of UR-13756 is realized using microwave dielectric heating and provides a highly selective inhibitor that shows excellent selectivity for p38 MAPK over c-Jun N-terminal kinase.
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Synthesis and evaluation of benzo[b]thiophene derivatives as inhibitors of alkaline phosphatases.
Li, Lina; Chang, Lei; Pellet-Rostaing, Stéphane; Liger, François; Lemaire, Marc; Buchet, René; Wu, Yuqing
2009-10-15
Presence of basic calcium phosphate in knee joints of osteoarthritis patients could be prevented by inhibiting tissue non-specific alkaline phosphatase (TNAP) activity. Levamisole or the L stereoisomer of tetramisole (a known TNAP inhibitor) has been used as a treatment for curing rheumatoid arthritis but its therapeutical use is limited due to side effects. We report the synthesis and the TNAP inhibition property of benzo[b]thiophene derivatives, among which benzothiopheno-tetramisole and benzothiopheno-2,3-dehydrotetramisole, which could be involved in a drug therapy for osteoarthritis. Two water soluble racemic benzothiopheno-tetramisole and -2,3-dehydrotetramisole with apparent inhibition constants K(i)=85+/-6 microM and 135+/-3 microM (n=3) comparable to that of enantiomeric levamisole 93+/-4 microM were found. Several novel derivatives showed more pronounced inhibition properties towards intestinal alkaline phosphatase than TNAP.
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Nelson, Kathryn M.; Viswanathan, Kishore; Dawadi, Surendra; Duckworth, Benjamin P.; Boshoff, Helena I.; Barry, Clifton E.; Aldrich, Courtney C.
2015-01-01
MbtA catalyzes the first committed biosynthetic step of the mycobactins, which are important virulence factors associated with iron acquisition in Mycobacterium tuberculosis. MbtA is a validated therapeutic target for antitubercular drug development. 5′-O-[N-(salicyl)sulfamoyl]adenosine (1) is a bisubstrate inhibitor of MbtA and exhibits exceptionally potent biochemical and antitubercular activity. However, 1 suffers from sub-optimal drug disposition properties resulting in a short half-life (t1/2), low exposure (AUC), and low bioavailability (F). Four strategies were pursued to address these liabilities including the synthesis of prodrugs, increasing the pKa of the acyl-sulfonyl moiety, modulation of the lipophilicity, and strategic introduction of fluorine into 1. Complete pharmacokinetic (PK) analysis of all compounds was performed. The most successful modifications involved fluorination of the nucleoside that provided substantial improvements in t1/2 and AUC. Increasing the pKa of the acyl-sulfonyl linker yielded incremental enhancements while modulation of the lipophilicity and prodrug approaches led to substantially poorer PK parameters. PMID:26110337
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Tang, Jun; Jones, Stacey A; Jeffery, Jerry L; Miranda, Sonia R; Galardi, Cristin M; Irlbeck, David M; Brown, Kevin W; McDanal, Charlene B; Han, Nianhe; Gao, Daxin; Wu, Yongyong; Shen, Bin; Liu, Chunyu; Xi, Caiming; Yang, Heping; Li, Rui; Yu, Yajun; Sun, Yufei; Jin, Zhimin; Wang, Erjuan; Johns, Brian A
2014-01-01
A macrocycle provides diverse functionality and stereochemical complexity in a conformationally preorganized ring structure, and it occupies a unique chemical space in drug discovery. However, the synthetic challenge to access this structural class is high and hinders the exploration of macrocycles. In this study, efficient synthetic routes to macrocyclized betulin derivatives have been established. The macrocycle containing compounds showed equal potency compared to bevirimat in multiple HIV-1 antiviral assays. The synthesis and biological evaluation of this novel series of HIV-1 maturation inhibitors will be discussed.
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Zidar, Nace; Tomašić, Tihomir; Šink, Roman; Kovač, Andreja; Patin, Delphine; Blanot, Didier; Contreras-Martel, Carlos; Dessen, Andréa; Premru, Manica Müller; Zega, Anamarija; Gobec, Stanislav; Mašič, Lucija Peterlin; Kikelj, Danijel
2011-11-01
Mur ligases (MurC-MurF), a group of bacterial enzymes that catalyze four consecutive steps in the formation of cytoplasmic peptidoglycan precursor, are becoming increasingly adopted as targets in antibacterial drug design. Based on the crystal structure of MurD cocrystallized with thiazolidine-2,4-dione inhibitor I, we have designed, synthesized, and evaluated a series of improved glutamic acid containing 5-benzylidenerhodanine and 5-benzylidenethiazolidine-2,4-dione inhibitors of MurD with IC(50) values up to 28 μM. Inhibitor 37, with an IC(50) of 34 μM, displays a weak antibacterial activity against S. aureus ATCC 29213 and E. faecalis ATCC 29212 with minimal inhibitory concentrations of 128 μg/mL. High-resolution crystal structures of MurD in complex with two new inhibitors (compounds 23 and 51) reveal details of their binding modes within the active site and provide valuable information for further structure-based optimization. Copyright © 2011 Elsevier Masson SAS. All rights reserved.
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Green synthesis of ZnO nanoparticles via complex formation by using Curcuma longa extract
NASA Astrophysics Data System (ADS)
Fatimah, Is; Yudha, Septian P.; Mutiara, Nur Afisa Lintang
2016-02-01
Synthesis of ZnO nanoparticles(NPs) were conducted via Zn(II) complex formation by using Curcuma longa extract as template. Curcuma longa extract has the ability to form zinc ions complex with curcumin as ligating agent. Study on synthesis was conducted by monitoring thermal degradation of the material. Successful formation of zinc oxide nanoparticles was confirmed by employing x-ray diffraction, surface area analysis and transmission electron microscopy(TEM) studies. From the XRD analysis it is denoted that ZnO in hexagonal wurtzite phase was formed and particle size was varied as varied temperature. The data are also confirmed by TEM analysis which shows the particle sie at the range 20-80nm. The NPs exhibited excelent photocatalytic activity for methylene blue degradation and also significant antibacterial activity for Eschericia coli. The activity in methylene blue degradation was also confirmed from fast chemical oxygen demand (COD) reduction.
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Synthesis of galabiose-chitosan conjugate as potent inhibitor of Streptococcus suis adhesion.
Xu, Yaozu; Fan, Hongjie; Lu, Chengping; Gao, George F; Li, Xuebing
2010-07-12
The aim of this work is to construct a safe and effective drug candidate against Streptococcus suis infection. A panel of chitosan-based polymer conjugates with branched galabiose (Galalpha1-4Gal) side chains was synthesized as inhibitors of S. suis adhesion. The synthesis was achieved by using an aldehyde-functionalized galabiose derivative to graft it onto chitosan amino groups. Structural compositions of the conjugates were verified by 1H NMR spectroscopy and CHN elemental analyses. Potent inhibitory activities of the conjugates against S. suis adhesion to human erythrocytes were determined at low nanomolar concentration by HAI assay. An SPR study revealed a high affinity binding (Kd=39.6 nM) of the conjugate with BSI-B4 lectin. By using biocompatible chitosan as the scaffold for presenting S. suis -specific galabiose units, as well as the concise route tailored for the conjugate syntheses, the present study provides a practical way for explorations of new anti- S. suis therapies.
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Synthesis and evaluation of carbocyanine dyes as PRMT inhibitors and imaging agents.
Sinha, Sarmistha Halder; Owens, Eric A; Feng, You; Yang, Yutao; Xie, Yan; Tu, Yaping; Henary, Maged; Zheng, Yujun George
2012-08-01
Protein arginine methylation regulates multiple biological processes. Deregulation of protein arginine methyltransferase (PRMT) activities has been observed in many disease phenotypes. Small molecule probes that target PRMTs with strong affinity and selectivity can be used as valuable tools to dissect biological mechanisms of arginine methylation and establish the role of PRMT proteins in a disease process. In this work, we report synthesis and evaluation of a class of carbocyanine compounds containing indolium, benz[e]indolium or benz[c,d]indolium heterocyclic moieties that bind to the predominant arginine methyltransferase PRMT1 and inhibit its methyltransferase activity at low micromolar potencies. In particular, the developed molecules have long wavelength colorimetric and fluorometric photoactivities, which can be used for optical and near-infrared fluorescence imaging in cells or biological tissues. Together, these new chemical probes have potential application in PRMT studies both as enzyme inhibitors and as fluorescent dyes for microscope imaging. Copyright © 2012 Elsevier Masson SAS. All rights reserved.
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Novel diamide-based inhibitors of IMPDH.
Gu, Henry H; Iwanowicz, Edwin J; Guo, Junqing; Watterson, Scott H; Shen, Zhongqi; Pitts, William J; Dhar, T G Murali; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Witmer, Mark; Tredup, Jeffrey; Hollenbaugh, Diane
2002-05-06
A series of novel amide-based small molecule inhibitors of inosine monophosphate dehydrogenase is described. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are presented.
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Inside HDAC with HDAC inhibitors.
Bertrand, Philippe
2010-06-01
Histone deacetylase inhibitors are a large group of diverse molecules intrinsically able to inhibit cell proliferation in various cancer cell lines. Their apoptotic effects have been linked to the modulation in the expression of several regulatory tumor suppressor genes caused by the modified status of histone acetylation, a key event in chromatin remodelling. As the initial histone deacetylase activity of HDAC has been extended to other proteins, the possible other biological mechanisms modified by HDAC inhibitor treatments are still to be clarified. The need for HDAC isoform selective inhibitors is an important issue to serve this goal. This review discusses the approaches proposed by several research groups working on the synthesis of HDAC inhibitors, based on modelling studies and the way these findings were used to obtain new HDAC inhibitors with possible isoform selectivity. Copyright (c) 2010 Elsevier Masson SAS. All rights reserved.
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Tang, Yong; Dou, Xiaoli; Hu, Jinguang; Jiang, Jianxin; Saddler, Jack N
2018-01-01
The merit of deacetylation of corn stover prior to pretreatment is decreasing the formation of inhibitors and improving enzyme hydrolysis, proved in dilute acid pretreatment. However, few studies are done on how deacetylation would affect bioconversion process containing steam explosion. In this study, the effect of deacetylation on steam explosion was conducted using poplar as substrate. About 57 to 90% of acetyl group in poplar, depending on alkaline types and concentration, was removed by dilute alkaline deacetylation in 6 h. Deacetylation eliminated over 85% of inhibitor formation during downstream steam explosion. However, deacetylation prior to steam explosion decreased the dissolution of hemicellulose, thus reducing the cellulose accessibility of pretreated poplar, finally resulting in 5-20% decrease in glucose yield and 20-35% decrease in xylose yield. The addition of 5% SO 2 during steam explosion significantly improved the hydrolysis of deacetylated and pretreated poplar without significantly increasing the concentration of inhibitors. Incorporating 45 mmol/kg sulfoacid group in lignin fraction of deacetylated and then pretreated poplar dramatically improved the xylose yield to about 100% and increased the glucose yield by 30%.
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Molecular pharmacological profile of the nonredox-type 5-lipoxygenase inhibitor CJ-13,610.
Fischer, Lutz; Steinhilber, Dieter; Werz, Oliver
2004-07-01
5-Lipoxygenase (5-LO) is a crucial enzyme in the synthesis of the bioactive leukotrienes (LTs) from arachidonic acid (AA), and inhibitors of 5-LO are thought to prevent the untowarded pathophysiological effects of LTs. In this study, we present the molecular pharmacological profile of the novel nonredox-type 5-LO inhibitor CJ-13,610 that was evaluated in various in vitro assays. In intact human polymorphonuclear leukocytes (PMNL), challenged with the Ca(2+)-ionophore A23187, CJ-13,610 potently suppressed 5-LO product formation with an IC(50)=0.07 microm. Supplementation of exogenous AA impaired the efficacy of CJ-13,610, implying a competitive mode of action. In analogy to ZM230487 and L-739.010, two closely related nonredox-type 5-LO inhibitors, CJ-13,610 up to 30 microm failed to inhibit 5-LO in cell-free assay systems under nonreducing conditions, but inclusion of peroxidase activity restored the efficacy of CJ-13,610 (IC(50)=0.3 microm). In contrast to ZM230487 and L-739.010, the potency of CJ-13,610 does not depend on the cell stimulus or the activation pathway of 5-LO. Thus, 5-LO product formation in PMNL induced by phosphorylation events was equally suppressed by CJ-13,610 as compared to Ca(2+)-mediated 5-LO activation. In transfected HeLa cells, CJ-13,610 only slightly discriminated between phosphorylatable wild-type 5-LO and a 5-LO mutant that lacks phosphorylation sites. In summary, CJ-13,610 may possess considerable potential as a potent orally active nonredox-type 5-LO inhibitor that lacks certain disadvantages of former representatives of this class of 5-LO inhibitors.
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2015-01-01
Design of small-molecule inhibitors (MDM2 inhibitors) to block the MDM2–p53 protein–protein interaction has been pursued as a new cancer therapeutic strategy. In recent years, potent, selective, and efficacious MDM2 inhibitors have been successfully obtained and seven such compounds have been advanced into early phase clinical trials for the treatment of human cancers. Here, we review the design, synthesis, properties, preclinical, and clinical studies of these clinical-stage MDM2 inhibitors. PMID:25396320
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Origins of the Mechanochemical Coupling of Peptide Bond Formation to Protein Synthesis.
Fritch, Benjamin; Kosolapov, Andrey; Hudson, Phillip; Nissley, Daniel A; Woodcock, H Lee; Deutsch, Carol; O'Brien, Edward P
2018-04-18
Mechanical forces acting on the ribosome can alter the speed of protein synthesis, indicating that mechanochemistry can contribute to translation control of gene expression. The naturally occurring sources of these mechanical forces, the mechanism by which they are transmitted 10 nm to the ribosome's catalytic core, and how they influence peptide bond formation rates are largely unknown. Here, we identify a new source of mechanical force acting on the ribosome by using in situ experimental measurements of changes in nascent-chain extension in the exit tunnel in conjunction with all-atom and coarse-grained computer simulations. We demonstrate that when the number of residues composing a nascent chain increases, its unstructured segments outside the ribosome exit tunnel generate piconewtons of force that are fully transmitted to the ribosome's P-site. The route of force transmission is shown to be through the nascent polypetide's backbone, not through the wall of the ribosome's exit tunnel. Utilizing quantum mechanical calculations we find that a consequence of such a pulling force is to decrease the transition state free energy barrier to peptide bond formation, indicating that the elongation of a nascent chain can accelerate translation. Since nascent protein segments can start out as largely unfolded structural ensembles, these results suggest a pulling force is present during protein synthesis that can modulate translation speed. The mechanism of force transmission we have identified and its consequences for peptide bond formation should be relevant regardless of the source of the pulling force.
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NASA Astrophysics Data System (ADS)
Yu, Wen; Hallinen, Kelsey; Wood, Kevin
Enterococcus faecalis are commonly associated with hospital acquired infections, because they readily form biofilms on instruments and medical devices. Biofilms are inherently more resistant to killing by antibiotics compared to planktonic bacteria, in part because of their heterogeneous spatial structure. Surprisingly, however, subminimal inhibitory concentrations (sub-MICs) of some antibiotics can actually promote biofilm formation. Unfortunately, much is still unknown about how low drug doses affect the composition and spatial structure of the biofilm. In this work, we investigate the effects of sub-MICs of ampicillin on the formation of E. faecalis biofilms. First, we quantified biofilm mass using crystal violet staining in polystyrene microtiter plates. We found that total biofilm mass is increased over a narrow range of ampicillin concentrations before ultimately declining at higher concentrations. Second, we show that sub-MICs of ampicillin can increase mass of E. faecalis biofilms while simultaneously increasing extracellular DNA/RNA and changing total number of viable cells under confocal microscopy. Further, we use RNA-seq to identify genes differentially expressed under sub-MICs of ampicillin. Finally, we show a mathematical model to explain this phenomenon. This work was funded by The Hartwell Foundation Individual Biomedical Research Award and NSF CAREER 1553208 to KBW.
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Discovery of novel selenium derivatives as Pin1 inhibitors by high-throughput screening
DOE Office of Scientific and Technical Information (OSTI.GOV)
Subedi, Amit; Graduate School of Science and Engineering, Saitama University, Saitama, 338-8570; Shimizu, Takeshi
2016-06-03
Peptidyl prolyl cis/trans isomerization by Pin1 regulates various oncogenic signals during cancer progression, and its inhibition through multiple approaches has established Pin1 as a therapeutic target. However, lack of simplified screening systems has limited the discovery of potent Pin1 inhibitors. We utilized phosphorylation-dependent binding of Pin1 to its specific substrate to develop a screening system for Pin1 inhibitors. Using this system, we screened a chemical library, and identified a novel selenium derivative as Pin1 inhibitor. Based on structure-activity guided chemical synthesis, we developed more potent Pin1 inhibitors that inhibited cancer cell proliferation. -- Highlights: •Novel screening for Pin1 inhibitors basedmore » on Pin1 binding is developed. •A novel selenium compound is discovered as Pin1 inhibitor. •Activity guided chemical synthesis of selenium derivatives resulted potent Pin1 inhibitors.« less
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Synthesis of ST7612AA1, a Novel Oral HDAC Inhibitor, via Radical Thioacetic Acid Addition.
Battistuzzi, Gianfranco; Giannini, Giuseppe
2016-12-01
In the expanding field of anticancer drugs, HDAC inhibitors are playing an increasingly important role. To date, four/five HDAC inhibitors have been approved by FDA. All these compounds fit the widely accepted HDAC inhibitors pharmacophore model characterized by a cap group, a linker chain and a zinc binding group (ZBG), able to bind the Zn 2+ ion in a pocket of the HDAC active site. Romidepsin, a natural compound, is the only thiol derivative. We have selected a new class of synthetic HDAC inhibitors, the thio-ω(lactam-carboxamide) derivatives, with ST7612AA1 as drug candidate, pan-inhibitor active in the range of single- to two-digit nanomolar concentrations. Preliminary results of a synthetic optimization attempt towards a fast scale-up process are here proposed. In the four steps of synthesis, from unsaturated amino acid intermediate to the final product, we explored different synthetic conditions in order to have a transferable process for a scale-up synthetic laboratory. In the first step, isobutyl chloroformate was used and, after a simple work up with 1M HCl, 2 (96% yield) was obtained as a white solid, which was used directly in the next step. For thioacetic acid addition to the double bond of intermediate 2 , two different routes were possible, with addition reaction in the first (D') or last step (D). Reactions of 2 to give 5 or of 4 to give ST7612AA1 were both performed in dioxane. Reactions were fast and did not need the usually advised radical quenching with cyclohexene. The corresponding products were obtained in good yields (step D', 89%; step D, 81%) after a flash chromatography. , a thiol derivative prodrug of ST7464AA1 , is the first of a new generation of HDAC inhibitors, very potent, orally administered, and well tolerated. Here, we have identified a synthetic route, competitive, versatile and easily transferable to industrial processes.
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Berube, Bryan J.; Murphy, Katherine R.; Torhan, Matthew C.; Bowlin, Nicholas O.; Williams, John D.; Bowlin, Terry L.; Moir, Donald T.
2017-01-01
ABSTRACT Pseudomonas aeruginosa is a leading cause of intra-abdominal infections, wound infections, and community-acquired folliculitis, each of which may involve macro- or microabscess formation. The rising incidence of multidrug resistance among P. aeruginosa isolates has increased both the economic burden and the morbidity and mortality associated with P. aeruginosa disease and necessitates a search for novel therapeutics. Previous work from our group detailed novel phenoxyacetamide inhibitors that block type III secretion and injection into host cells in vitro. In this study, we used a mouse model of P. aeruginosa abscess formation to test the in vivo efficacy of these compounds against the P. aeruginosa type III secretion system (T3SS). Bacteria used the T3SS to intoxicate infiltrating neutrophils to establish abscesses. Despite this antagonism, sufficient numbers of functioning neutrophils remained for proper containment of the abscesses, as neutrophil depletion resulted in an increased abscess size, the formation of dermonecrotic lesions on the skin, and the dissemination of P. aeruginosa to internal organs. Consistent with the specificity of the T3SS-neutrophil interaction, P. aeruginosa bacteria lacking a functional T3SS were fully capable of causing abscesses in a neutropenic host. Phenoxyacetamide inhibitors attenuated abscess formation and aided in the immune clearance of the bacteria. Finally, a P. aeruginosa strain resistant to the phenoxyacetamide compound was fully capable of causing abscess formation even in the presence of the T3SS inhibitors. Together, our results further define the role of type III secretion in murine abscess formation and demonstrate the in vivo efficacy of phenoxyacetamide inhibitors in P. aeruginosa infection. PMID:28807906
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Green synthesis of ZnO nanoparticles via complex formation by using Curcuma longa extract
DOE Office of Scientific and Technical Information (OSTI.GOV)
Fatimah, Is, E-mail: isfatimah@uii.ac.id; Yudha, Septian P.; Mutiara, Nur Afisa Lintang
Synthesis of ZnO nanoparticles(NPs) were conducted via Zn(II) complex formation by using Curcuma longa extract as template. Curcuma longa extract has the ability to form zinc ions complex with curcumin as ligating agent. Study on synthesis was conducted by monitoring thermal degradation of the material. Successful formation of zinc oxide nanoparticles was confirmed by employing x-ray diffraction, surface area analysis and transmission electron microscopy(TEM) studies. From the XRD analysis it is denoted that ZnO in hexagonal wurtzite phase was formed and particle size was varied as varied temperature. The data are also confirmed by TEM analysis which shows the particlemore » sie at the range 20-80nm. The NPs exhibited excelent photocatalytic activity for methylene blue degradation and also significant antibacterial activity for Eschericia coli. The activity in methylene blue degradation was also confirmed from fast chemical oxygen demand (COD) reduction.« less
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Therapeutic potential of monoacylglycerol lipase inhibitors.
Mulvihill, Melinda M; Nomura, Daniel K
2013-03-19
Marijuana and aspirin have been used for millennia to treat a wide range of maladies including pain and inflammation. Both cannabinoids, like marijuana, that exert anti-inflammatory action through stimulating cannabinoid receptors, and cyclooxygenase (COX) inhibitors, like aspirin, that suppress pro-inflammatory eicosanoid production have shown beneficial outcomes in mouse models of neurodegenerative diseases and cancer. Both cannabinoids and COX inhibitors, however, have untoward effects that discourage their chronic usage, including cognitive deficits and gastrointestinal toxicity, respectively. Recent studies have uncovered that the serine hydrolase monoacylglycerol lipase (MAGL) links the endocannabinoid and eicosanoid systems together through hydrolysis of the endocannabinoid 2-arachidonoylglycerol (2-AG) to provide the major arachidonic acid (AA) precursor pools for pro-inflammatory eicosanoid synthesis in specific tissues. Studies in recent years have shown that MAGL inhibitors elicit anti-nociceptive, anxiolytic, and anti-emetic responses and attenuate precipitated withdrawal symptoms in addiction paradigms through enhancing endocannabinoid signaling. MAGL inhibitors have also been shown to exert anti-inflammatory action in the brain and protect against neurodegeneration through lowering eicosanoid production. In cancer, MAGL inhibitors have been shown to have anti-cancer properties not only through modulating the endocannabinoid-eicosanoid network, but also by controlling fatty acid release for the synthesis of protumorigenic signaling lipids. Thus, MAGL serves as a critical node in simultaneously coordinating multiple lipid signaling pathways in both physiological and disease contexts. This review will discuss the diverse (patho)physiological roles of MAGL and the therapeutic potential of MAGL inhibitors in treating a vast array of complex human diseases. Copyright © 2012 Elsevier Inc. All rights reserved.
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Longshaw, Alistair I.; Adanitsch, Florian; Gutierrez, Jemy A.; Evans, Gary B.; Tyler, Peter C.; Schramm, Vern L.
2013-01-01
5′-Methylthioadenosine/S-adenosylhomocysteine nucleosidase (MTAN) is a dual substrate bacterial enzyme involved in S-adenosylmethionine (SAM)-related quorum sensing pathways that regulates virulence in many bacterial species. MTANs from many bacteria are directly involved in the quorum sensing mechanism by regulating the synthesis of autoinducer molecules that are used by bacterial communities to communicate. In humans, 5′-methylthioadenosine phosphorylase (MTAP) is involved in polyamine biosynthesis as well as in purine and SAM salvage pathways and thus has been identified as an anticancer target. Previously we have described the synthesis and biological activity of several aza-C-nucleoside mimics with a sulfur atom at the 5′ position that are potent E. coli MTAN and human MTAP inhibitors. Because of the possibility that the sulfur may affect bioavailability we were interested in synthesizing “sulfur-free” analogues. Herein we describe the preparation of a series of “sulfur-free” transition state analogues inhibitors, of E. coli MTAN and human MTAP that have low nano- to pico-molar dissociation constants and are potentially novel bacterial anti-infective and anti-cancer drug candidates. PMID:20718423
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Fierro-Monti, Ivo; Racle, Julien; Hernandez, Celine; Waridel, Patrice; Hatzimanikatis, Vassily; Quadroni, Manfredo
2013-01-01
Standard proteomics methods allow the relative quantitation of levels of thousands of proteins in two or more samples. While such methods are invaluable for defining the variations in protein concentrations which follow the perturbation of a biological system, they do not offer information on the mechanisms underlying such changes. Expanding on previous work [1], we developed a pulse-chase (pc) variant of SILAC (stable isotope labeling by amino acids in cell culture). pcSILAC can quantitate in one experiment and for two conditions the relative levels of proteins newly synthesized in a given time as well as the relative levels of remaining preexisting proteins. We validated the method studying the drug-mediated inhibition of the Hsp90 molecular chaperone, which is known to lead to increased synthesis of stress response proteins as well as the increased decay of Hsp90 “clients”. We showed that pcSILAC can give information on changes in global cellular proteostasis induced by treatment with the inhibitor, which are normally not captured by standard relative quantitation techniques. Furthermore, we have developed a mathematical model and computational framework that uses pcSILAC data to determine degradation constants kd and synthesis rates Vs for proteins in both control and drug-treated cells. The results show that Hsp90 inhibition induced a generalized slowdown of protein synthesis and an increase in protein decay. Treatment with the inhibitor also resulted in widespread protein-specific changes in relative synthesis rates, together with variations in protein decay rates. The latter were more restricted to individual proteins or protein families than the variations in synthesis. Our results establish pcSILAC as a viable workflow for the mechanistic dissection of changes in the proteome which follow perturbations. Data are available via ProteomeXchange with identifier PXD000538. PMID:24312217
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Meyer, Andrew C; Neugebauer, Nichole M; Zheng, Guangrong; Crooks, Peter A; Dwoskin, Linda P; Bardo, Michael T
2013-10-01
Vesicular monoamine transporter-2 (VMAT2) inhibitors reduce methamphetamine (METH) reward in rats. The current study determined the effects of VMAT2 inhibitors lobeline (LOB; 1 or 3 mg/kg) and N-(1,2R-dihydroxylpropyl)-2,6-cis-di(4-methoxyphenethyl)piperidine hydrochloride (GZ-793A; 15 or 30 mg/kg) on METH-induced (0.5 mg/kg, SC) changes in extracellular dopamine (DA) and its metabolite dihydroxyphenylacetic acid (DOPAC) in the reward-relevant nucleus accumbens (NAc) shell using in vivo microdialysis. The effect of GZ-793A (15 mg/kg) on DA synthesis in tissue also was investigated in NAc, striatum, medial prefrontal cortex and orbitofrontal cortex. In NAc shell, METH produced a time-dependent increase in extracellular DA and decrease in DOPAC. Neither LOB nor GZ-793A alone altered extracellular DA; however, both drugs increased extracellular DOPAC. In combination with METH, LOB did not alter the effects of METH on DA; however, GZ-793A, which has greater selectivity than LOB for inhibiting VMAT2, reduced the duration of the METH-induced increase in extracellular DA. Both LOB and GZ-793A enhanced the duration of the METH-induced decrease in extracellular DOPAC. METH also increased tissue DA synthesis in NAc and striatum, whereas GZ-793A decreased synthesis; no effect of METH or GZ-793A on DA synthesis was found in medial prefrontal cortex or orbitofrontal cortex. These results suggest that selective inhibition of VMAT2 produces a time-dependent decrease in DA release in NAc shell as a result of alterations in tyrosine hydroxylase activity, which may play a role in the ability of GZ-793A to decrease METH reward. © 2013 International Society for Neurochemistry.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Benzine, Tiffany; Brandt, Ryan; Lovell, William C.
We synthesized the Hepatitis C virus (HCV) RNA by the replicase complex (RC), a macromolecular assembly composed of viral non-structural proteins and cellular co-factors. Inhibitors of the HCV NS5A protein block formation of new RCs but do not affect RNA synthesis by preformed RCs. Without new RC formation, existing RCs turn over and are eventually lost from the cell. We aimed to use NS5A inhibitors to estimate the half-life of the functional RC of HCV. We compared different cell culture-infectious strains of HCV that may be grouped based on their sensitivity to lipid peroxidation: robustly replicating, lipid peroxidation resistant (LPOmore » R) viruses (e.g. JFH-1 or H77D) and more slowly replicating, lipid peroxidation sensitive (LPO S) viruses (e.g. H77S.3 and N.2). Furthermore, in luciferase assays, LPO S HCV strains declined under NS5A inhibitor therapy with much slower kinetics compared to LPO R HCV strains. This difference in rate of decline was not observed for inhibitors of the NS5B RNAdependent RNA polymerase suggesting that the difference was not simply a consequence of differences in RNA stability. In further analyses, we compared two isoclonal HCV variants: the LPO S H77S.3 and the LPO R H77D that differ only by 12 amino acids. Differences in rate of decline between H77S.3 and H77D following NS5A inhibitor addition were not due to amino acid sequences in NS5A but rather due to a combination of amino acid differences in the non-structural proteins that make up the HCV RC. The mathematical modeling of intracellular HCV RNA dynamics suggested that differences in RC stability (half-lives of 3.5 and 9.9 hours, for H77D and H77S.3, respectively) are responsible for the different kinetics of antiviral suppression between LPO S and LPO R viruses. In nascent RNA capture assays, the rate of RNA synthesis decline following NS5A inhibitor addition was significantly faster for H77D compared to H77S.3 indicating different half-lives of functional RCs.« less
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Benzine, Tiffany; Brandt, Ryan; Lovell, William C.; ...
2017-06-08
We synthesized the Hepatitis C virus (HCV) RNA by the replicase complex (RC), a macromolecular assembly composed of viral non-structural proteins and cellular co-factors. Inhibitors of the HCV NS5A protein block formation of new RCs but do not affect RNA synthesis by preformed RCs. Without new RC formation, existing RCs turn over and are eventually lost from the cell. We aimed to use NS5A inhibitors to estimate the half-life of the functional RC of HCV. We compared different cell culture-infectious strains of HCV that may be grouped based on their sensitivity to lipid peroxidation: robustly replicating, lipid peroxidation resistant (LPOmore » R) viruses (e.g. JFH-1 or H77D) and more slowly replicating, lipid peroxidation sensitive (LPO S) viruses (e.g. H77S.3 and N.2). Furthermore, in luciferase assays, LPO S HCV strains declined under NS5A inhibitor therapy with much slower kinetics compared to LPO R HCV strains. This difference in rate of decline was not observed for inhibitors of the NS5B RNAdependent RNA polymerase suggesting that the difference was not simply a consequence of differences in RNA stability. In further analyses, we compared two isoclonal HCV variants: the LPO S H77S.3 and the LPO R H77D that differ only by 12 amino acids. Differences in rate of decline between H77S.3 and H77D following NS5A inhibitor addition were not due to amino acid sequences in NS5A but rather due to a combination of amino acid differences in the non-structural proteins that make up the HCV RC. The mathematical modeling of intracellular HCV RNA dynamics suggested that differences in RC stability (half-lives of 3.5 and 9.9 hours, for H77D and H77S.3, respectively) are responsible for the different kinetics of antiviral suppression between LPO S and LPO R viruses. In nascent RNA capture assays, the rate of RNA synthesis decline following NS5A inhibitor addition was significantly faster for H77D compared to H77S.3 indicating different half-lives of functional RCs.« less
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Ionothermal Synthesis and Magnetic Studies of Novel Two-Dimensional Metal-Formate Frameworks
DOE Office of Scientific and Technical Information (OSTI.GOV)
Calderone, P.; Feygenson, M.; Forster, P.M.
2011-03-21
Five novel two-dimensional frameworks containing formate-bridged metal-centered octahedra are synthesized ionothermally from two ionic liquids previously unused as solvents in hybrid synthesis, 2-hydroxyethylammonium (HEA) formate, and 1-hydroxy-3-proplyammonium (HPA) formate. Templating effects of the cation from each ionic liquid drive the formation of different structures. [NH{sub 3}C{sub 2}H{sub 4}OH]{sub 2}[M(CHO{sub 2}){sub 4}] (1: M = Co, 2: M = Ni) exhibit the same stoichiometry and connectivity as their manganese analogue (3: M = Mn), but the manganese form exhibits a different topology from 1 and 2. [NH{sub 3}C{sub 3}H6OH][M(CHO{sub 2}){sub 3}(H{sub 2}O)] (4: M = Co, 5: M = Mn) weremore » synthesized using the HPA formate ionic liquid with a metal-formate connectivity related to those of 1-3. Canted antiferromagnetic ordering occurs at low temperatures (1: T{sub N} = 7.0 K, 2: T{sub N} = 4.6 K, 3: T{sub N} = 8.0 K, 4: T{sub N} = 7.0 K, 5: T{sub N} = 9.2 K), similar to the magnetic properties previously reported for other metal-formate hybrid materials.« less
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Properties of inhibitors of methane hydrate formation via molecular dynamics simulations.
Anderson, Brian J; Tester, Jefferson W; Borghi, Gian Paolo; Trout, Bernhardt L
2005-12-21
Within the framework of a proposed two-step mechanism for hydrate inhibition, the energy of binding of four inhibitor molecules (PEO, PVP, PVCap, and VIMA) to a hydrate surface is estimated with molecular dynamic simulations. One key feature of this proposed mechanism is that the binding of an inhibitor molecule to the surface of an ensuing hydrate crystal disrupts growth and therein crystallization. It is found through the molecular dynamic simulations that inhibitor molecules that experimentally exhibit better inhibition strength also have higher free energies of binding, an indirect confirmation of our proposed mechanism. Inhibitors increasing in effectiveness, PEO < PVP < PVCap < VIMA, have increasingly negative (exothermic) binding energies of -0.2 < -20.6 < -37.5 < -45.8 kcal/mol and binding free energies of increasing favorability (+0.4 approximately = +0.5 < -9.4 < -15.1 kcal/mol). Furthermore, the effect of an inhibitor molecule on the local liquid water structure under hydrate-forming conditions was examined and correlated to the experimental effectiveness of the inhibitors. Two molecular characteristics that lead to strongly binding inhibitors were found: (1) a charge distribution on the edge of the inhibitor that mimics the charge separation in the water molecules on the surface of the hydrate and (2) the congruence of the size of the inhibitor with respect to the available space at the hydrate-surface binding site. Equipped with this molecular-level understanding of the process of hydrate inhibition via low-dosage kinetic hydrate inhibitors we can design new, more effective inhibitor molecules.
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Novel guanidine-based inhibitors of inosine monophosphate dehydrogenase.
Iwanowicz, Edwin J; Watterson, Scott H; Liu, Chunjian; Gu, Henry H; Mitt, Toomas; Leftheris, Katerina; Barrish, Joel C; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Hollenbaugh, Diane L
2002-10-21
A series of novel guanidine-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. IMPDH catalyzes the rate determining step in guanine nucleotide biosynthesis and is a target for anticancer, immunosuppressive and antiviral therapy. The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for this new series of inhibitors is given.
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Thioredoxin Inhibitors Attenuate Platelet Function and Thrombus Formation
Metcalfe, Clive; Ramasubramoni, Anjana; Pula, Giordano; Harper, Matthew T.; Mundell, Stuart J.; Coxon, Carmen H.
2016-01-01
Thioredoxin (Trx) is an oxidoreductase with important physiological function. Imbalances in the NADPH/thioredoxin reductase/thioredoxin system are associated with a number of pathologies, particularly cancer, and a number of clinical trials for thioredoxin and thioredoxin reductase inhibitors have been carried out or are underway. Due to the emerging role and importance of oxidoreductases for haemostasis and the current interest in developing inhibitors for clinical use, we thought it pertinent to assess whether inhibition of the NADPH/thioredoxin reductase/thioredoxin system affects platelet function and thrombosis. We used small molecule inhibitors of Trx (PMX 464 and PX-12) to determine whether Trx activity influences platelet function, as well as an unbiased proteomics approach to identify potential Trx substrates on the surface of platelets that might contribute to platelet reactivity and function. Using LC-MS/MS we found that PMX 464 and PX-12 affected the oxidation state of thiols in a number of cell surface proteins. Key surface receptors for platelet adhesion and activation were affected, including the collagen receptor GPVI and the von Willebrand factor receptor, GPIb. To experimentally validate these findings we assessed platelet function in the presence of PMX 464, PX-12, and rutin (a selective inhibitor of the related protein disulphide isomerase). In agreement with the proteomics data, small molecule inhibitors of thioredoxin selectively inhibited GPVI-mediated platelet activation, and attenuated ristocetin-induced GPIb-vWF-mediated platelet agglutination, thus validating the findings of the proteomics study. These data reveal a novel role for thioredoxin in regulating platelet reactivity via proteins required for early platelet responses at sites of vessel injury (GPVI and GPIb). This work also highlights a potential opportunity for repurposing of PMX 464 and PX-12 as antiplatelet agents. PMID:27716777
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Thioredoxin Inhibitors Attenuate Platelet Function and Thrombus Formation.
Metcalfe, Clive; Ramasubramoni, Anjana; Pula, Giordano; Harper, Matthew T; Mundell, Stuart J; Coxon, Carmen H
2016-01-01
Thioredoxin (Trx) is an oxidoreductase with important physiological function. Imbalances in the NADPH/thioredoxin reductase/thioredoxin system are associated with a number of pathologies, particularly cancer, and a number of clinical trials for thioredoxin and thioredoxin reductase inhibitors have been carried out or are underway. Due to the emerging role and importance of oxidoreductases for haemostasis and the current interest in developing inhibitors for clinical use, we thought it pertinent to assess whether inhibition of the NADPH/thioredoxin reductase/thioredoxin system affects platelet function and thrombosis. We used small molecule inhibitors of Trx (PMX 464 and PX-12) to determine whether Trx activity influences platelet function, as well as an unbiased proteomics approach to identify potential Trx substrates on the surface of platelets that might contribute to platelet reactivity and function. Using LC-MS/MS we found that PMX 464 and PX-12 affected the oxidation state of thiols in a number of cell surface proteins. Key surface receptors for platelet adhesion and activation were affected, including the collagen receptor GPVI and the von Willebrand factor receptor, GPIb. To experimentally validate these findings we assessed platelet function in the presence of PMX 464, PX-12, and rutin (a selective inhibitor of the related protein disulphide isomerase). In agreement with the proteomics data, small molecule inhibitors of thioredoxin selectively inhibited GPVI-mediated platelet activation, and attenuated ristocetin-induced GPIb-vWF-mediated platelet agglutination, thus validating the findings of the proteomics study. These data reveal a novel role for thioredoxin in regulating platelet reactivity via proteins required for early platelet responses at sites of vessel injury (GPVI and GPIb). This work also highlights a potential opportunity for repurposing of PMX 464 and PX-12 as antiplatelet agents.
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Dao, Pascal; Jarray, Rafika; Le Coq, Johanne; Lietha, Daniel; Loukaci, Ali; Lepelletier, Yves; Hadj-Slimane, Réda; Garbay, Christiane; Raynaud, Françoise; Chen, Huixiong
2013-08-15
We report herein the synthesis of novel diarylamino-1,3,5-triazine derivatives as FAK (focal adhesion kinase) inhibitors and the evaluation of their anti-angiogenic activity on HUVEC cells. Generally, the effects of these compounds on endothelial cells could be correlated with their kinase inhibitory activity. The most efficient compounds displayed inhibition of viability against HUVEC cells in the micromolar range, as observed with TAE-226, which was designed by Novartis Pharma AG. X-ray crystallographic analysis of the co-crystal structure for compound 34 revealed that the mode of interaction with the FAK kinase domain is highly similar to that observed in the complex of TAE-226. Copyright © 2013 Elsevier Ltd. All rights reserved.
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NASA Technical Reports Server (NTRS)
Varma, Arvind; Mukasyan, Alexander; Pelekh, Aleksey
1997-01-01
There have been relatively few publications examining the role of gravity during combustion synthesis (CS), mostly involving thermite systems. The main goal of this research was to study the influence of gravity on the combustion characteristics of heterogeneous gasless systems. In addition, some aspects of microstructure formation processes which occur during gasless CS were also studied. Four directions for experimental investigation have been explored: (1) the influence of gravity force on the characteristic features of heterogeneous combustion wave propagation (average velocity, instantaneous velocities, shape of combustion front); (2) the combustion of highly porous mixtures (with porosity greater than that for loose powders), which cannot be obtained in normal gravity; (3) the effect of gravity on sample expansion during combustion, in order to produce highly porous materials under microgravity conditions; and (4) the effect of gravity on the structure formation mechanism during the combustion synthesis of poreless composite materials.
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Arias, D G; Herrera, F E; Garay, A S; Rodrigues, D; Forastieri, P S; Luna, L E; Bürgi, M D L M; Prieto, C; Iglesias, A A; Cravero, R M; Guerrero, S A
2017-01-05
The rational design and synthesis of a series of 5-nitro-2-furoic acid analogues are presented. The trypanocidal activity against epimastigote forms of Trypanosoma cruzi and the toxic effects on human HeLa cells were tested. Between all synthetic compounds, three of thirteen had an IC 50 value in the range of Nfx, but compound 13 exhibited an improved effect with an IC 50 of 1.0 ± 0.1 μM and a selective index of 70 in its toxicity against HeLa cells. We analyzed the activity of compounds 8, 12 and 13 to interfere in the central redox metabolic pathway in trypanosomatids, which is dependent of reduced trypanothione as the major pivotal thiol. The three compounds behaved as better inhibitors of trypanothione reductase than Nfx (Ki values of 118 μM, 61 μM and 68 μM for 8, 12 and 13, respectively, compared with 245 μM for Nfx), all following an uncompetitive enzyme inhibition pattern. Docking analysis predicted a binding of inhibitors to the enzyme-substrate complex with binding energy calculated in-silico that supports such molecular interaction. Copyright © 2016 Elsevier Masson SAS. All rights reserved.
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Design, Synthesis, and Properties of a Potent Inhibitor of Pseudomonas aeruginosa Deacetylase LpxC.
Piizzi, Grazia; Parker, David T; Peng, Yunshan; Dobler, Markus; Patnaik, Anup; Wattanasin, Som; Liu, Eugene; Lenoir, Francois; Nunez, Jill; Kerrigan, John; McKenney, David; Osborne, Colin; Yu, Donghui; Lanieri, Leanne; Bojkovic, Jade; Dzink-Fox, JoAnn; Lilly, Maria-Dawn; Sprague, Elizabeth R; Lu, Yipin; Wang, Hongming; Ranjitkar, Srijan; Xie, Lili; Wang, Bing; Glick, Meir; Hamann, Lawrence G; Tommasi, Ruben; Yang, Xia; Dean, Charles R
2017-06-22
Over the past several decades, the frequency of antibacterial resistance in hospitals, including multidrug resistance (MDR) and its association with serious infectious diseases, has increased at alarming rates. Pseudomonas aeruginosa is a leading cause of nosocomial infections, and resistance to virtually all approved antibacterial agents is emerging in this pathogen. To address the need for new agents to treat MDR P. aeruginosa, we focused on inhibiting the first committed step in the biosynthesis of lipid A, the deacetylation of uridyldiphospho-3-O-(R-hydroxydecanoyl)-N-acetylglucosamine by the enzyme LpxC. We approached this through the design, synthesis, and biological evaluation of novel hydroxamic acid LpxC inhibitors, exemplified by 1, where cytotoxicity against mammalian cell lines was reduced, solubility and plasma-protein binding were improved while retaining potent anti-pseudomonal activity in vitro and in vivo.
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Baas-Espinola, Fray M; Castro-Concha, Lizbeth A; Vázquez-Flota, Felipe A; Miranda-Ham, María L
2016-06-21
Capsaicinoids (CAP) are nitrogenous metabolites formed from valine (Val) and phenylalanine (Phe) in the placentas of hot Capsicum genotypes. Placentas of Habanero peppers can incorporate inorganic nitrogen into amino acids and have the ability to secure the availability of the required amino acids for CAP biosynthesis. In order to determine the participation of the placental tissue as a supplier of these amino acids, the effects of blocking the synthesis of Val and Phe by using specific enzyme inhibitors were analyzed. Isolated placentas maintained in vitro were used to rule out external sources' participation. Blocking Phe synthesis, through the inhibition of arogenate dehydratase, significantly decreased CAP accumulation suggesting that at least part of Phe required in this process has to be produced in situ. Chlorsulfuron inhibition of acetolactate synthase, involved in Val synthesis, decreased not only Val accumulation but also that of CAP, pointing out that the requirement for this amino acid can also be fulfilled by this tissue. The presented data demonstrates that CAP accumulation in in vitro maintained placentas can be accomplished through the in situ availability of Val and Phe and suggests that the synthesis of the fatty acid chain moiety may be a limiting factor in the biosynthesis of these alkaloids.
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Bhatia, M; Landolfi, C; Basta, F; Bovi, G; Ramnath, R Devi; de Joannon, A Capezzone; Guglielmotti, A
2008-10-01
Chemokines play a fundamental role in trafficking and activation of leukocytes in colonic inflammation. We investigated the ability of bindarit, an inhibitor of monocyte chemoattractant protein-1 (MCP-1/CCL2) synthesis, to inhibit chemokine production by human intestinal epithelial cells (HT-29) and its effect in trinitro-benzene sulfonic acid (TNBS)-induced colitis in mice. HT-29 cells were incubated with bindarit in the presence of TNF-alpha/IFN-gamma and 24 h later supernatants were collected for MCP-1, IL-8 and RANTES measurement. A 1 mg enema of TNBS was given to BALB/c mice, and bindarit (100 mg/kg) was orally administered twice daily starting from two days before colitis induction. Weight loss, histology, and MCP-1 level and myeloperoxidase (MPO) activity in colon extracts were assessed. In HT-29 cells, bindarit concentration-dependently and selectively inhibited MCP-1 secretion (as well as mRNA expression) primed by TNF-alpha/IFN-gamma. Moreover treatment with bindarit reduced clinical and histopathological severity of TNBS-induced colitis. These effects were associated with significant inhibition of MCP-1 and MPO in colon extracts. Bindarit exhibits a potent bioactivity in reducing leukocyte infiltration, down-regulating MCP-1 synthesis, and preventing the development of severe colitis in a mice model of TNBS-induced colitis. These observations suggest a potential use of MCP-1 synthesis blockers in intestinal inflammation in humans.
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A novel high-throughput screening format to identify inhibitors of secreted acid sphingomyelinase.
Mintzer, Robert J; Appell, Kenneth C; Cole, Andrew; Johns, Anthony; Pagila, Rene; Polokoff, Mark A; Tabas, Ira; Snider, R Michael; Meurer-Ogden, Janet A
2005-04-01
Secreted extracellular acid sphingomyelinase (sASM) activity has been suggested to promote atherosclerosis by enhancing subendothelial aggregation and retention of low-density lipoprotein (LDL) with resultant foam cell formation. Compounds that inhibit sASM activity, at neutral pH, may prevent lipid retention and thus would be expected to be anti-atherosclerotic. With the goal of identifying novel compounds that inhibit sASM at pH 7.4, a high-throughput screen was performed. Initial screening was run using a modification of a proven system that measures the hydrolysis of radiolabeled sphingomyelin presented in detergent micelles in a 96-well format. Separation of the radiolabeled aqueous phosphorylcholine reaction product from uncleaved sphingomyelin lipid substrate was achieved by chloroform/methanol extraction. During the screening campaign, a novel extraction procedure was developed to eliminate the use of the hazardous organic reagents. This new procedure exploited the ability of uncleaved, radiolabeled lipid substrate to interact with hydrophobic phenyl-sepharose beads. A comparison of the organic-based and the bead-based extraction sASM screening assays revealed Z' factor values ranging from 0.7 to 0.95 for both formats. In addition, both assay formats led to the identification of sub- to low micromolar inhibitors of sASM at pH 7.4 with similar IC(50) values. Subsequent studies demonstrated that both methods were also adaptable to run in a 384-well format. In contrast to the results observed at neutral pH, however, only the organic extraction assay was capable of accurately measuring sASM activity at its pH optimum of 5.0. The advantages and disadvantages of both sASM assay formats are discussed.
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de Aquino, Roney Anderson Nascimento; Modolo, Luzia Valentina; Alves, Rosemeire Brondi; de Fátima, Ângelo
2013-12-28
This study presents the synthesis of 15 new tacrine dimers as well as the Ki and IC50 results, studies of the kinetic mechanism, and molecular docking analysis of the dimers in relation to the cholinesterases hAChE, hBChE, EeAChE and eqBChE. In addition to spectroscopic characterization, X-ray structure determination was performed for two of the new compounds. These new dimers were found to be mixed nanomolar inhibitors of the evaluated targets with a broad and significant selectivity profile, and these properties are dependent on both the type of the linker and the volume of the hydroacridine alicyclic ring. The results indicate that the aromatic linkers play a significant role in generating specific interactions with the half-gorge region of the catalytic center. Thus, these types of linkers can positively modulate the electronic properties of the tacrine dimers studied with an improvement of their cholinesterase inhibition activity.
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Pardo, Beatriz; Rodrigues, Tiago B; Contreras, Laura; Garzón, Miguel; Llorente-Folch, Irene; Kobayashi, Keiko; Saheki, Takeyori; Cerdan, Sebastian; Satrústegui, Jorgina
2011-01-01
The glutamate-glutamine cycle faces a drain of glutamate by oxidation, which is balanced by the anaplerotic synthesis of glutamate and glutamine in astrocytes. De novo synthesis of glutamate by astrocytes requires an amino group whose origin is unknown. The deficiency in Aralar/AGC1, the main mitochondrial carrier for aspartate-glutamate expressed in brain, results in a drastic fall in brain glutamine production but a modest decrease in brain glutamate levels, which is not due to decreases in neuronal or synaptosomal glutamate content. In vivo (13)C nuclear magnetic resonance labeling with (13)C(2)acetate or (1-(13)C) glucose showed that the drop in brain glutamine is due to a failure in glial glutamate synthesis. Aralar deficiency induces a decrease in aspartate content, an increase in lactate production, and lactate-to-pyruvate ratio in cultured neurons but not in cultured astrocytes, indicating that Aralar is only functional in neurons. We find that aspartate, but not other amino acids, increases glutamate synthesis in both control and aralar-deficient astrocytes, mainly by serving as amino donor. These findings suggest the existence of a neuron-to-astrocyte aspartate transcellular pathway required for astrocyte glutamate synthesis and subsequent glutamine formation. This pathway may provide a mechanism to transfer neuronal-born redox equivalents to mitochondria in astrocytes.
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Matsuda, Daisuke; Tomoda, Hiroshi
2007-10-01
Obesity is characterized by the accumulation of triacylglycerol in adipocytes. Diacylglycerol acyltransferase (DGAT) catalyzes the final reaction of triacylgycerol synthesis. Two isozymes of DGAT, DGAT1 and DGAT2, have been reported. Increased DGAT2 activity has a role in steatosis, while DGAT1 plays a role in very (V)LDL synthesis; increased plasma VLDL concentrations may promote obesity and thus DGAT1 is considered a potential therapeutic target of inhibition for obesity control. Several DGAT inhibitors of natural and synthetic origin have been reported, and their future prospect as anti-obesity drugs is discussed in this review.
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Guo, Cheng; Hu, Min; DeOrazio, Russell J; Usyatinsky, Alexander; Fitzpatrick, Kevin; Zhang, Zhenjun; Maeng, Jun-Ho; Kitchen, Douglas B; Tom, Susan; Luche, Michele; Khmelnitsky, Yuri; Mhyre, Andrew J; Guzzo, Peter R; Liu, Shuang
2014-07-01
The sodium glucose co-transporter 2 (SGLT2) has received considerable attention in recent years as a target for the treatment of type 2 diabetes mellitus. This report describes the design, synthesis and structure-activity relationship (SAR) of C-glycosides with benzyltriazolopyridinone and phenylhydantoin as the aglycone moieties as novel SGLT2 inhibitors. Compounds 5p and 33b demonstrated high potency in inhibiting SGLT2 and high selectivity against SGLT1. The in vitro ADMET properties of these compounds will also be discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Zhang, Zhen; Zhao, Dongmei; Dai, Yang; Cheng, Maosheng; Geng, Meiyu; Shen, Jingkang; Ma, Yuchi; Ai, Jing; Xiong, Bing
2016-10-23
Tyrosine kinase fibroblast growth factor receptor (FGFR), which is aberrant in various cancer types, is a promising target for cancer therapy. Here we reported the design, synthesis, and biological evaluation of a new series of 6-(2,6-dichloro-3,5-dimethoxyphenyl)-4-substituted-1 H -indazole derivatives as potent FGFR inhibitors. The compound 6-(2,6-dichloro-3,5-dimethoxyphenyl)- N -phenyl-1 H -indazole-4-carboxamide ( 10a ) was identified as a potent FGFR1 inhibitor, with good enzymatic inhibition. Further structure-based optimization revealed that 6-(2,6-dichloro-3,5-dimethoxyphenyl)- N -(3-(4-methylpiperazin-1-yl)phenyl)-1 H -indazole-4-carboxamide ( 13a ) is the most potent FGFR1 inhibitor in this series, with an enzyme inhibitory activity IC 50 value of about 30.2 nM.
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Hasegawa, Hirohiko; Muraoka, Masami; Ohmori, Mikiko; Matsui, Kazuki; Kojima, Atsuyuki
2005-10-01
Design, synthesis, and structure-activity relationships for 3,4-dihydropyridopyrimidin-2(1H)-one derivatives, which are aza-3,4-dihydro-2(1H)-quinazolinone derivatives, as the sodium/calcium (Na+/Ca2+) exchanger inhibitors are discussed. These studies based on 3,4-dihydro-2(1H)-quinazolinone derivatives led to the discovery of a structurally novel and potent Na+/Ca2+ exchanger inhibitor, 3,4-dihydropyridopyrimidin-2(1H)-one derivative (26), with an IC30 value of 0.02 microM. Compound 26 directly inhibited the Na+-dependent Ca2+ influx via the Na+/Ca2+ exchanger after Na+-free treatment in cardiomyocytes.
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Thanigaimalai, Pillaiyar; Konno, Sho; Yamamoto, Takehito; Koiwai, Yuji; Taguchi, Akihiro; Takayama, Kentaro; Yakushiji, Fumika; Akaji, Kenichi; Kiso, Yoshiaki; Kawasaki, Yuko; Chen, Shen-En; Naser-Tavakolian, Aurash; Schön, Arne; Freire, Ernesto; Hayashi, Yoshio
2013-07-01
This work describes the design, synthesis, and evaluation of low-molecular weight peptidic SARS-CoV 3CL protease inhibitors. The inhibitors were designed based on the potent tripeptidic Z-Val-Leu-Ala(pyrrolidone-3-yl)-2-benzothiazole (8; Ki = 4.1 nM), in which the P3 valine unit was substituted with a variety of distinct moieties. The resulting series of dipeptide-type inhibitors displayed moderate to good inhibitory activities against 3CL(pro). In particular, compounds 26m and 26n exhibited good inhibitory activities with Ki values of 0.39 and 0.33 μM, respectively. These low-molecular weight compounds are attractive leads for the further development of potent peptidomimetic inhibitors with pharmaceutical profiles. Docking studies were performed to model the binding interaction of the compound 26m with the SARS-CoV 3CL protease. The preliminary SAR study of the peptidomimetic compounds with potent inhibitory activities revealed several structural features that boosted the inhibitory activity: (i) a benzothiazole warhead at the S1' position, (ii) a γ-lactam unit at the S1-position, (iii) an appropriately hydrophobic leucine moiety at the S2-position, and (iv) a hydrogen bond between the N-arylglycine unit and a backbone hydrogen bond donor at the S3-position. Copyright © 2013 Elsevier Masson SAS. All rights reserved.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Osterman, Ilya A.; Khabibullina, Nelli F.; Komarova, Ekaterina S.
The emergence of multi-drug resistant bacteria is limiting the effectiveness of commonly used antibiotics, which spurs a renewed interest in revisiting older and poorly studied drugs. Streptogramins A is a class of protein synthesis inhibitors that target the peptidyl transferase center (PTC) on the large subunit of the ribosome. In this work, we have revealed the mode of action of the PTC inhibitor madumycin II, an alanine-containing streptogramin A antibiotic, in the context of a functional 70S ribosome containing tRNA substrates. Madumycin II inhibits the ribosome prior to the first cycle of peptide bond formation. It allows binding of themore » tRNAs to the ribosomal A and P sites, but prevents correct positioning of their CCA-ends into the PTC thus making peptide bond formation impossible. We also revealed a previously unseen drug-induced rearrangement of nucleotides U2506 and U2585 of the 23S rRNA resulting in the formation of the U2506•G2583 wobble pair that was attributed to a catalytically inactive state of the PTC. The structural and biochemical data reported here expand our knowledge on the fundamental mechanisms by which peptidyl transferase inhibitors modulate the catalytic activity of the ribosome.« less
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Liu, J.; Bolstad, D; Smith, A
2009-01-01
Candida glabrata, a fungal strain resistant to many commonly administered antifungal agents, has become an emerging threat to human health. In previous work, we validated that the essential enzyme, dihydrofolate reductase, is a drug target in C. glabrata. Using a crystal structure of dihydrofolate reductase from C. glabrata bound to an initial lead compound, we designed a class of biphenyl antifolates that potently and selectively inhibit both the enzyme and the growth of the fungal culture. In this work, we explore the structure-activity relationships of this class of antifolates with four new high resolution crystal structures of enzyme:inhibitor complexes andmore » the synthesis of four new inhibitors. The designed inhibitors are intended to probe key hydrophobic pockets visible in the crystal structure. The crystal structures and an evaluation of the new compounds reveal that methyl groups at the meta and para positions of the distal phenyl ring achieve the greatest number of interactions with the pathogenic enzyme and the greatest degree of selectivity over the human enzyme. Additionally, antifungal activity can be tuned with substitution patterns at the propargyl and para-phenyl positions.« less
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Franchetti, Palmarisa; Cappellacci, Loredana; Pasqualini, Michela; Petrelli, Riccardo; Jayaprakasan, Vetrichelvan; Jayaram, Hiremagalur N; Boyd, Donald B; Jain, Manojkumar D; Grifantini, Mario
2005-03-15
Thiazole-4-carboxamide adenine dinucleotide (TAD) analogues T-2'-MeAD (1) and T-3'-MeAD (2) containing, respectively, a methyl group at the ribose 2'-C-, and 3'-C-position of the adenosine moiety, were prepared as potential selective human inosine monophosphate dehydrogenase (IMPDH) type II inhibitors. The synthesis of heterodinucleotides was carried out by CDI-catalyzed coupling reaction of unprotected 2'-C-methyl- or 3'-C-methyl-adenosine 5'-monophosphate with 2',3'-O-isopropylidene-tiazofurin 5'-monophosphate, and then deisopropylidenation. Biological evaluation of dinucleotides 1 and 2 as inhibitors of recombinant human IMPDH type I and type II resulted in a good activity. Inhibition of both isoenzymes by T-2'-MeAD and T-3'-MeAD was noncompetitive with respect to NAD substrate. Binding of T-3'-MeAD was comparable to that of parent compound TAD, while T-2'-MeAD proved to be a weaker inhibitor. However, no significant difference was found in inhibition of the IMPDH isoenzymes. T-2'-MeAD and T-3'-MeAD were found to inhibit the growth of K562 cells (IC(50) 30.7 and 65.0muM, respectively).
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dell'Erba, Ignacio E; Martínez, Francisco D; Hoppe, Cristina E; Eliçabe, Guillermo E; Ceolín, Marcelo; Zucchi, Ileana A; Schroeder, Walter F
2017-10-03
A detailed understanding of the processes taking place during the in situ synthesis of metal/polymer nanocomposites is crucial to manipulate the shape and size of nanoparticles (NPs) with a high level of control. In this paper, we report an in-depth time-resolved analysis of the particle formation process in silver/epoxy nanocomposites obtained through a visible-light-assisted in situ synthesis. The selected epoxy monomer was based on diglycidyl ether of bisphenol A, which undergoes relatively slow cationic ring-opening polymerization. This feature allowed us to access a full description of the formation process of silver NPs before this was arrested by the curing of the epoxy matrix. In situ time-resolved small-angle X-ray scattering investigation was carried out to follow the evolution of the number and size of the silver NPs as a function of irradiation time, whereas rheological experiments combined with near-infrared and ultraviolet-visible spectroscopies were performed to interpret how changes in the rheological properties of the matrix affect the nucleation and growth of particles. The analysis of the obtained results allowed us to propose consistent mechanisms for the formation of metal/polymer nanocomposites obtained by light-assisted one-pot synthesis. Finally, the effect of a thermal postcuring treatment of the epoxy matrix on the particle size in the nanocomposite was investigated.
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1975-01-01
A wide variety of inhibitors (drugs, antibiotics, and antimetabolites) will block cell division within an ongoing cell cycle in autotrophic cultures of Chlamydomonas reinhardtii. To determine when during the cell cycle a given inhibitor is effective in preventing cell division, a technique is described which does not rely on the use of synchronous cultures. The technique permits the measurement of transition points, the cell cycle stage at which the subsequent cell division becomes insensitive to the effects of an inhibitor. A map of transition points in the cell cycle reveals that they are grouped into two broad periods, the second and fourth quarters. In general, inhibitors which block organellar DNA, RNA, and protein synthesis have second-quarter transition points, while those which inhibit nuclear cytoplasmic macromolecular synthesis have fourth-quarter transition points. The specific grouping of these transition points into two periods suggests that the synthesis of organellar components is completed midway through the cell cycle and that the synthesis of nonorganellar components required for cell division is not completed until late in the cell cycle. PMID:1176526
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Inhibitors of biofilm formation by biofuel fermentation contaminants.
Leathers, Timothy D; Bischoff, Kenneth M; Rich, Joseph O; Price, Neil P J; Manitchotpisit, Pennapa; Nunnally, Melinda S; Anderson, Amber M
2014-10-01
Biofuel fermentation contaminants such as Lactobacillus sp. may persist in production facilities by forming recalcitrant biofilms. In this study, biofilm-forming strains of Lactobacillus brevis, Lactobacillus fermentum, and Lactobacillus plantarum were isolated and characterized from a dry-grind fuel ethanol plant. A variety of potential biofilm inhibitors were tested, including microbial polysaccharides, commercial enzymes, ferric ammonium citrate, liamocins, phage endolysin, xylitol, and culture supernatants from Bacillus sp. A commercial enzyme mixture (Novozyme 188) and culture supernatants from Bacillus subtilis strains ALT3A and RPT-82412 were identified as the most promising biofilm inhibitors. In biofilm flow cells, these inhibitors reduced the density of viable biofilm cells by 0.8-0.9 log cfu/cm(2). Unlike B. subtilis strain RPT-82412, B. subtilis strain ALT3A and Novozyme 188 did not inhibit planktonic growth of Lactobacillus sp. MALDI-TOF mass spectra showed the production of surfactin-like molecules by both B. subtilis strains, and the coproduction of iturin-like molecules by strain RPT-82412. Published by Elsevier Ltd.
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NASA Astrophysics Data System (ADS)
Ronco, M. P.; Guilera, O. M.; de Elía, G. C.
2017-11-01
Population synthesis models of planetary systems developed during the last ˜15 yr could reproduce several of the observables of the exoplanet population, and also allowed us to constrain planetary formation models. We present our planet formation model, which calculates the evolution of a planetary system during the gaseous phase. The code incorporates relevant physical phenomena for the formation of a planetary system, like photoevaporation, planet migration, gas accretion, water delivery in embryos and planetesimals, a detailed study of the orbital evolution of the planetesimal population, and the treatment of the fusion between embryos, considering their atmospheres. The main goal of this work, unlike other works of planetary population synthesis, is to find suitable scenarios and physical parameters of the disc to form Solar system analogues. We are specially interested in the final planet distributions, and in the final surface density, eccentricity and inclination profiles for the planetesimal population. These final distributions will be used as initial conditions for N-body simulations to study the post-oligarchic formation in a second work. We then consider different formation scenarios, with different planetesimal sizes and different type I migration rates. We find that Solar system analogues are favoured in massive discs, with low type I migration rates, and small planetesimal sizes. Besides, those rocky planets within their habitables zones are dry when discs dissipate. At last, the final configurations of Solar system analogues include information about the mass and semimajor axis of the planets, water contents, and the properties of the planetesimal remnants.
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Phytochelatin synthesis and glutathione levels in response to heavy metals in tomato cells.
Scheller, H V; Huang, B; Hatch, E; Goldsbrough, P B
1987-12-01
Cell suspension cultures of tomato, Lycopersicon esculentum Mill. cv VFNT-Cherry, produce phytochelatins (poly[gamma-glutamylcysteinyl]glycines) when exposed to cadmium. The synthesis of these peptides is accompanied by a decline in cellular levels of glutathione. Buthionine sulfoximine, an inhibitor of glutathione synthesis, inhibits the sustained production of phytochelatins. However, phytochelatin synthesis can occur in the presence of buthionine sulfoximine provided that sufficient glutathione is available. These results indicate that glutathione is a substrate for phytochelatin synthesis. The protein synthesis inhibitor cycloheximide does not affect the initial production of phytochelatin.
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Suthar, Sharad Kumar; Bansal, Sumit; Narkhede, Niteen; Guleria, Manju; Alex, Angel Treasa; Joseph, Alex
2017-01-01
The enzyme tyrosinase regulates melanogenesis and skin hyperpigmentation by converting L-3,4-dihydroxyphenylalanine (L-DOPA) into dopaquinone, a key step in the melanin biosynthesis. The present work deals with design and synthesis of various oxindole-based chalcones as monophenolase and diphenolase activity inhibitors of tyrosinase. Among the screened compounds, 4-hydroxy-3-methoxybenzylidene moiety bearing chalcone (7) prepared by one pot reaction of oxindole and vanillin displayed the highest activity against tyrosinase with IC 50 s of 63.37 and 59.71 µM in monophenolase and diphenolase activity assays, respectively. In molecular docking studies, chalcone 7 also showed the highest binding affinity towards the enzyme tyrosinase while exhibiting the lowest estimated free energy of binding, among all the ligands docked.
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Kim, MunJu; Reed, Damon; Rejniak, Katarzyna A.
2014-01-01
Cyclin-dependent kinases (CDKs) are vital in regulating cell cycle progression, and, thus, in highly proliferating tumor cells CDK inhibitors are gaining interest as potential anticancer agents. Clonogenic assay experiments are frequently used to determine drug efficacy against the survival and proliferation of cancer cells. While the anticancer mechanisms of drugs are usually described at the intracellular single-cell level, the experimental measurements are sampled from the entire cancer cell population. This approach may lead to discrepancies between the experimental observations and theoretical explanations of anticipated drug mechanisms. To determine how individual cell responses to drugs that inhibit CDKs affect the growth of cancer cell populations, we developed a spatially explicit hybrid agent-based model. In this model, each cell is equipped with internal cell cycle regulation mechanisms, but it is also able to interact physically with its neighbors. We model cell cycle progression, focusing on the G1 and G2/M cell cycle checkpoints, as well as on related essential components, such as CDK1, CDK2, cell size, and DNA damage. We present detailed studies of how the emergent properties (e.g., cluster formation) of an entire cell population depend on altered physical and physiological parameters. We analyze the effects of CDK1 and CKD2 inhibitors on population growth, time-dependent changes in cell cycle distributions, and the dynamic evolution of spatial cell patterns. We show that cell cycle inhibitors that cause cell arrest at different cell cycle phases are not necessarily synergistically super-additive. Finally, we demonstrate that the physical aspects of cell population growth, such as the formation of tight cell clusters versus dispersed colonies, alter the efficacy of cell cycle inhibitors, both in 2D and 3D simulations. This finding may have implications for interpreting the treatment efficacy results of in vitro experiments, in which treatment is
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Brefeldin A Inhibits Cell-Free, De Novo Synthesis of Poliovirus
Cuconati, Andrea; Molla, Akhteruzzaman; Wimmer, Eckard
1998-01-01
Brefeldin A (BFA), an inhibitor of intracellular vesicle-dependent secretory transport, is a potent inhibitor of poliovirus RNA replication in infected cells. We have determined that the unknown mechanism of BFA inhibition of replication is reproduced in the cell-free poliovirus translation, replication, and encapsidation system. Furthermore, we provide evidence suggesting that the cellular mechanism targeted by BFA, the GTP-dependent synthesis of secretory transport vesicles, may be involved in viral RNA replication in the system via a soluble cellular GTP-binding and -hydrolyzing activity. This activity is related to the ARF (ADP-ribosylation factor) family of GTP-binding proteins. ARFs are required for the formation of several classes of secretory vesicles, and some family members are indirectly inactivated by BFA. Peptides that function as competitive inhibitors of ARF activity in cell-free transport systems also inhibit poliovirus RNA replication, and this inhibitory effect can be countered by the addition of exogenous ARF. We suggest that BFA inhibition of replication is diagnostic of a requirement for ARF activity in the cell-free system. PMID:9658088
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Formation of organoclays by a one step synthesis
NASA Astrophysics Data System (ADS)
Jaber, Maguy; Miéhé-Brendlé, Jocelyne; Delmotte, Luc; Le Dred, Ronan
2005-05-01
Different lamellar hybrid inorganic-organic materials having as inorganic parent 2:1 (T.O.T.) phyllosilicates such as talc, saponite, pyrophyllite, beidellite and montmorillonite were prepared by a one step synthesis. The solids were characterized by X-ray diffraction, solid state 29Si, 27Al, and 19F nuclear magnetic resonance and transmission electron microscopy. XRD patterns show that solids with inorganic parents having octahedral sheet based on aluminium exhibit a lamellar structure similar to MCM-50, whereas those with magnesium have an organophyllosilicate structure. In the first case, the absence of hexacoordinated aluminium was confirmed by 27Al NMR and an ordered stacking of the layers is observed on TEM micrographs. In opposite, a disorder is observed on the TEM images of organophyllosilicates. The formation of the 2:1 structure was found to be controlled mainly by the insertion of silicic species in the interlamellar space of brucite like layers.
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2016-01-01
MCC950 is an orally bioavailable small molecule inhibitor of the NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome that exhibits remarkable activity in multiple models of inflammatory disease. Incubation of MCC950 with human liver microsomes, and subsequent analysis by HPLC–MS/MS, revealed a major metabolite, where hydroxylation of MCC950 had occurred on the 1,2,3,5,6,7-hexahydro-s-indacene moiety. Three possible regioisomers were synthesized, and coelution using HPLC–MS/MS confirmed the structure of the metabolite. Further synthesis of individual enantiomers and coelution studies using a chiral column in HPLC–MS/MS showed the metabolite was R-(+)- N-((1-hydroxy-1,2,3,5,6,7-hexahydro-s-indacen-4-yl)carbamoyl)-4-(2-hydroxypropan-2-yl)furan-2-sulfonamide (2a). Incubation of MCC950 with a panel of cytochrome P450 enzymes showed P450s 2A6, 2C9, 2C18, 2C19, 2J2, and 3A4 catalyze the formation of the major metabolite 2a, with a lower level of activity shown by P450s 1A2 and 2B6. All of the synthesized compounds were tested for inhibition of NLRP3-induced production of the pro-inflammatory cytokine IL-1β from human monocyte derived macrophages. The identified metabolite 2a was 170-fold less potent than MCC950, while one regioisomer had nanomolar inhibitory activity. These findings also give first insight into the SAR of the hexahydroindacene moiety. PMID:27994733
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Salla, Manohar; Butler, Mark S; Pelingon, Ruby; Kaeslin, Geraldine; Croker, Daniel E; Reid, Janet C; Baek, Jong Min; Bernhardt, Paul V; Gillam, Elizabeth M J; Cooper, Matthew A; Robertson, Avril A B
2016-12-08
MCC950 is an orally bioavailable small molecule inhibitor of the NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome that exhibits remarkable activity in multiple models of inflammatory disease. Incubation of MCC950 with human liver microsomes, and subsequent analysis by HPLC-MS/MS, revealed a major metabolite, where hydroxylation of MCC950 had occurred on the 1,2,3,5,6,7-hexahydro- s -indacene moiety. Three possible regioisomers were synthesized, and coelution using HPLC-MS/MS confirmed the structure of the metabolite. Further synthesis of individual enantiomers and coelution studies using a chiral column in HPLC-MS/MS showed the metabolite was R -(+)- N -((1-hydroxy-1,2,3,5,6,7-hexahydro- s -indacen-4-yl)carbamoyl)-4-(2-hydroxypropan-2-yl)furan-2-sulfonamide ( 2a ). Incubation of MCC950 with a panel of cytochrome P450 enzymes showed P450s 2A6, 2C9, 2C18, 2C19, 2J2, and 3A4 catalyze the formation of the major metabolite 2a , with a lower level of activity shown by P450s 1A2 and 2B6. All of the synthesized compounds were tested for inhibition of NLRP3-induced production of the pro-inflammatory cytokine IL-1β from human monocyte derived macrophages. The identified metabolite 2a was 170-fold less potent than MCC950, while one regioisomer had nanomolar inhibitory activity. These findings also give first insight into the SAR of the hexahydroindacene moiety.
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NASA Technical Reports Server (NTRS)
Pedrozo, H. A.; Schwartz, Z.; Dean, D. D.; Harrison, J. L.; Campbell, J. W.; Wiederhold, M. L.; Boyan, B. D.
1997-01-01
To better understand the mechanisms that could modulate the formation of otoconia, calcium carbonate granules in the inner ear of vertebrate species, we examined statoconia formation in the gravity-sensing organ, the statocyst, of the gastropod mollusk Aplysia californica using an in vitro organ culture model. We determined the type of calcium carbonate present in the statoconia and investigated the role of carbonic anhydrase (CA) and urease in regulating statocyst pH as well as the role of protein synthesis and urease in statoconia production and homeostasis in vitro. The type of mineral present in statoconia was found to be aragonitic calcium carbonate. When the CA inhibitor, acetazolamide (AZ), was added to cultures of statocysts, the pH initially (30 min) increased and then decreased. The urease inhibitor, acetohydroxamic acid (AHA), decreased statocyst pH. Simultaneous addition of AZ and AHA caused a decrease in pH. Inhibition of urease activity also reduced total statoconia number, but had no effect on statoconia volume. Inhibition of protein synthesis reduced statoconia production and increased statoconia volume. In a previous study, inhibition of CA was shown to decrease statoconia production. Taken together, these data show that urease and CA play a role in regulating statocyst pH and the formation and maintenance of statoconia. CA produces carbonate ion for calcium carbonate formation and urease neutralizes the acid formed due to CA action, by production of ammonia.
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Tantry, Subramanyam J; Markad, Shankar D; Shinde, Vikas; Bhat, Jyothi; Balakrishnan, Gayathri; Gupta, Amit K; Ambady, Anisha; Raichurkar, Anandkumar; Kedari, Chaitanyakumar; Sharma, Sreevalli; Mudugal, Naina V; Narayan, Ashwini; Naveen Kumar, C N; Nanduri, Robert; Bharath, Sowmya; Reddy, Jitendar; Panduga, Vijender; Prabhakar, K R; Kandaswamy, Karthikeyan; Saralaya, Ramanatha; Kaur, Parvinder; Dinesh, Neela; Guptha, Supreeth; Rich, Kirsty; Murray, David; Plant, Helen; Preston, Marian; Ashton, Helen; Plant, Darren; Walsh, Jarrod; Alcock, Peter; Naylor, Kathryn; Collier, Matthew; Whiteaker, James; McLaughlin, Robert E; Mallya, Meenakshi; Panda, Manoranjan; Rudrapatna, Suresh; Ramachandran, Vasanthi; Shandil, Radha; Sambandamurthy, Vasan K; Mdluli, Khisi; Cooper, Christopher B; Rubin, Harvey; Yano, Takahiro; Iyer, Pravin; Narayanan, Shridhar; Kavanagh, Stefan; Mukherjee, Kakoli; Balasubramanian, V; Hosagrahara, Vinayak P; Solapure, Suresh; Ravishankar, Sudha; Hameed P, Shahul
2017-02-23
The approval of bedaquiline to treat tuberculosis has validated adenosine triphosphate (ATP) synthase as an attractive target to kill Mycobacterium tuberculosis (Mtb). Herein, we report the discovery of two diverse lead series imidazo[1,2-a]pyridine ethers (IPE) and squaramides (SQA) as inhibitors of mycobacterial ATP synthesis. Through medicinal chemistry exploration, we established a robust structure-activity relationship of these two scaffolds, resulting in nanomolar potencies in an ATP synthesis inhibition assay. A biochemical deconvolution cascade suggested cytochrome c oxidase as the potential target of IPE class of molecules, whereas characterization of spontaneous resistant mutants of SQAs unambiguously identified ATP synthase as its molecular target. Absence of cross resistance against bedaquiline resistant mutants suggested a different binding site for SQAs on ATP synthase. Furthermore, SQAs were found to be noncytotoxic and demonstrated efficacy in a mouse model of tuberculosis infection.
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Kun, Sándor; Begum, Jaida; Kyriakis, Efthimios; Stamati, Evgenia C V; Barkas, Thomas A; Szennyes, Eszter; Bokor, Éva; Szabó, Katalin E; Stravodimos, George A; Sipos, Ádám; Docsa, Tibor; Gergely, Pál; Moffatt, Colin; Patraskaki, Myrto S; Kokolaki, Maria C; Gkerdi, Alkistis; Skamnaki, Vassiliki T; Leonidas, Demetres D; Somsák, László; Hayes, Joseph M
2018-03-10
3-(β-d-Glucopyranosyl)-5-substituted-1,2,4-triazoles have been revealed as an effective scaffold for the development of potent glycogen phosphorylase (GP) inhibitors but with the potency very sensitive to the nature of the alkyl/aryl 5-substituent (Kun et al., Eur. J. Med. Chem. 2014, 76, 567). For a training set of these ligands, quantum mechanics-polarized ligand docking (QM-PLD) demonstrated good potential to identify larger differences in potencies (predictive index PI = 0.82) and potent inhibitors with K i 's < 10 μM (AU-ROC = 0.86). Accordingly, in silico screening of 2335 new analogues exploiting the ZINC docking database was performed and nine predicted candidates selected for synthesis. The compounds were prepared in O-perbenzoylated forms by either ring transformation of 5-β-d-glucopyranosyl tetrazole by N-benzyl-arenecarboximidoyl chlorides, ring closure of C-(β-d-glucopyranosyl)formamidrazone with aroyl chlorides, or that of N-(β-d-glucopyranosylcarbonyl)arenethiocarboxamides by hydrazine, followed by deprotections. Kinetics experiments against rabbit muscle GPb (rmGPb) and human liver GPa (hlGPa) revealed five compounds as potent low μM inhibitors with three of these on the submicromolar range for rmGPa. X-ray crystallographic analysis sourced the potency to a combination of favorable interactions from the 1,2,4-triazole and suitable aryl substituents in the GP catalytic site. The compounds also revealed promising calculated pharmacokinetic profiles. Copyright © 2018 Elsevier Masson SAS. All rights reserved.
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Yun, Young Sung; Kim, Kwan Hyun; Tschida, Barbara; Sachs, Zohar; Noble-Orcutt, Klara E; Moriarity, Branden S; Ai, Teng; Ding, Rui; Williams, Jessica; Chen, Liqiang; Largaespada, David; Kim, Do-Hyung
2016-02-18
Reduction of translational fidelity often occurs in cells with high rates of protein synthesis, generating defective ribosomal products. If not removed, such aberrant proteins can be a major source of cellular stress causing human diseases. Here, we demonstrate that mTORC1 promotes the formation of immunoproteasomes for efficient turnover of defective proteins and cell survival. mTORC1 sequesters precursors of immunoproteasome β subunits via PRAS40. When activated, mTORC1 phosphorylates PRAS40 to enhance protein synthesis and simultaneously to facilitate the assembly of the β subunits for forming immunoproteasomes. Consequently, the PRAS40 phosphorylations play crucial roles in clearing aberrant proteins that accumulate due to mTORC1 activation. Mutations of RAS, PTEN, and TSC1, which cause mTORC1 hyperactivation, enhance immunoproteasome formation in cells and tissues. Those mutations increase cellular dependence on immunoproteasomes for stress response and survival. These results define a mechanism by which mTORC1 couples elevated protein synthesis with immunoproteasome biogenesis to protect cells against protein stress. Copyright © 2016 Elsevier Inc. All rights reserved.
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Thermoresponsive Microcarriers for Smart Release of Hydrate Inhibitors under Shear Flow.
Lee, Sang Seok; Park, Juwoon; Seo, Yutaek; Kim, Shin-Hyun
2017-05-24
The hydrate formation in subsea pipelines can cause oil and gas well blowout. To avoid disasters, various chemical inhibitors have been developed to prevent or delay the hydrate formation and growth. Nevertheless, direct injection of the inhibitors results in environmental contamination and cross-suppression of inhibition performance in the presence of other inhibitors against corrosion and/or formation of scale, paraffin, and asphaltene. Here, we suggest a new class of microcarriers that encapsulate hydrate inhibitors at high concentration and release them on demand without active external triggering. The key to the success in microcarrier design lies in the temperature dependence of polymer brittleness. The microcarriers are microfluidically created to have an inhibitor-laden water core and polymer shell by employing water-in-oil-in-water (W/O/W) double-emulsion drops as a template. As the polymeric shell becomes more brittle at a lower temperature, there is an optimum range of shell thickness that renders the shell unstable at temperature responsible for hydrate formation under a constant shear flow. We precisely control the shell thickness relative to the radius by microfluidics and figure out the optimum range. The microcarriers with the optimum shell thickness are selectively ruptured by shear flow only at hydrate formation temperature and release the hydrate inhibitors. We prove that the released inhibitors effectively retard the hydrate formation without reduction of their performance. The microcarriers that do not experience the hydration formation temperature retain the inhibitors, which can be easily separated from ruptured ones for recycling by exploiting the density difference. Therefore, the use of microcarriers potentially minimizes the environmental damages.
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Ning, Xia; Wang, Yue; Yan, Wei; Li, Guangke; Sang, Nan
2018-05-03
Chitin synthesis inhibitors (CSIs), as alternatives to conventional insecticides, have been in worldwide demand in recent years. However, little attention has been paid to the potential ecological safety and health risks of CSIs, especially their abilities to interfere with nonsexual hormone receptors such as hypoxia-inducible factor 1α (HIF-1α). In this work, we conducted a systematic study regarding the influence of CSIs on HIF-1α-related liver cancer cell metastasis. The dual-luciferase reporter gene assay revealed that two of fourteen CSIs exhibited dose-response HIF-1α agonistic activities at noncytotoxic concentrations with relative luciferase activity (RLA) values of 25.6% for diflubenzuron (DFB) and 20.9% for triflumuron (TFM). Following this result, in vitro bioassays demonstrated that both DFB and TFM stimulated HepG2 cell migration and invasion. This action was associated with the varied expression levels of genes involved in epithelial-to-mesenchymal transition (EMT) activation and extracellular matrix (ECM) degradation, such as the upregulation of fibronectin (FN1) and matrix metalloproteinase-2 (MMP-2) and the suppression of E-cadherin (E-cad) and tissue inhibitor of metalloproteinases-2 (TIMP-2). Moreover, changes in these EMT and ECM phenotype markers were dramatically blocked by a HIF-1α inhibitor (KC7F2), which further verified the involvement of HIF-1α in CSI-induced HepG2 cell metastasis. For the first time, our findings reveal that CSIs play crucial roles in promoting the metastasis of human liver cancer cells and that HIF-1α is potentially responsible for these changes. Copyright © 2018 Elsevier Ltd. All rights reserved.
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NASA Astrophysics Data System (ADS)
Hariono, Maywan; Abdullah, Nurshariza; Damodaran, K. V.; Kamarulzaman, Ezatul E.; Mohamed, Nornisah; Hassan, Sharifah Syed; Shamsuddin, Shaharum; Wahab, Habibah A.
2016-12-01
We report the computational and experimental efforts in the design and synthesis of novel neuraminidase (NA) inhibitors from ferulic acid and vanillin. Two proposed ferulic acid analogues, MY7 and MY8 were predicted to inhibit H1N1 NA using molecular docking. From these two analogues, we designed, synthesised and evaluated the biological activities of a series of ferulic acid and vanillin derivatives. The enzymatic H1N1 NA inhibition assay showed MY21 (a vanillin derivative) has the lowest IC50 of 50 μM. In contrast, the virus inhibition assay showed MY15, a ferulic acid derivative has the best activity with the EC50 of ~0.95 μM. Modelling studies further suggest that these predicted activities might be due to the interactions with conserved and essential residues of NA with ΔGbind values comparable to those of oseltamivir and zanamivir, the two commercial NA inhibitors.
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Synthesis of three bromophenols from red algae as PTP1B inhibitors
NASA Astrophysics Data System (ADS)
Guo, Shuju; Li, Jing; Li, Ting; Shi, Dayong; Han, Lijun
2011-01-01
Bromophenols are a set of natural products widely distributed in seaweed, most of which exhibit interesting and useful biological activities. To develop a reliable and efficient synthetic route to these natural bromophenols, three of them, 3,4-dibromo-5-(2'-bromo-3',4'-dihydroxy-6'-methoxymethyl-benzyl)-benzene-1,2-diol (compound 9), 3,4-dibromo-5-(2'-bromo-6'-ethoxy methyl-3',4'-dihydroxybenzyl)-benzene-1,2-diol (compound 10), and 3-bromo-4-(3'-bromo-4',5'-dihydroxy benzyl)-5-(ethoxymethyl)-benzene-1,2-diol (compound 14), isolated from red marine algae, have been synthesized in eight steps with an overall yield of 14.4%, 14.4%, and 18.2% respectively, via a practical approach employing bromination, Wolff-Kishner-Huang reduction and a Friedel-Crafts reaction as key steps. The protein tyrosine phosphatase 1B (PTP1B) inhibitory activities of the synthetic compounds were evaluated by the colorimetric assay. The results show that these compounds are moderate PTP1B inhibitors. The synthesis of these bromophenol derivatives makes in vivo studies of their structure-activity relationships and inhibition activity against PTP1B possible.
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Bar-Peled, Maor; Urbanowicz, Breeanna R.; O’Neill, Malcolm A.
2012-01-01
There is compelling evidence showing that the structurally complex pectic polysaccharide rhamnogalacturonan II (RG-II) exists in the primary cell wall as a borate cross-linked dimer and that this dimer is required for the assembly of a functional wall and for normal plant growth and development. The results of several studies have also established that RG-II structure and cross-linking is conserved in vascular plants and that RG-II likely appeared early in the evolution of land plants. Two features that distinguish RG-II from other plant polysaccharides are that RG-II is composed of 13 different glycoses linked to each other by up to 22 different glycosidic linkages and that RG-II is the only polysaccharide known to contain both apiose and aceric acid. Thus, one key event in land plant evolution was the emergence of genes encoding nucleotide sugar biosynthetic enzymes that generate the activated forms of apiose and aceric acid required for RG-II synthesis. Many of the genes involved in the generation of the nucleotide sugars used for RG-II synthesis have been functionally characterized. By contrast, only one glycosyltransferase involved in the assembly of RG-II has been identified. Here we provide an overview of the formation of the activated sugars required for RG-II synthesis and point to the possible cellular and metabolic processes that could be involved in assembling and controlling the formation of a borate cross-linked RG-II molecule. We discuss how nucleotide sugar synthesis is compartmentalized and how this may control the flux of precursors to facilitate and regulate the formation of RG-II. PMID:22639675
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Moroni, Flavio; Carpenedo, Raffaella; Cozzi, Andrea; Meli, Elena; Chiarugi, Alberto; Pellegrini-Giampietro, Domenico E
2003-01-01
Kynurenine 3-mono-oxygenase (KMO) inhibitors facilitate kynurenic acid (KYNA) neosynthesis and reduce the formation of 3OH-kynurenine (3-HK) and quinolinic acid (QUIN). They also attenuate post-ischemic brain damage and decrease glutamate (Glu) content in brain extracellular spaces. To investigate KMO mechanism(s) of neuroprotection, we performed experiments in gerbils subjected to bilateral carotid occlusion and in organotypic rat hippocampal slice cultures exposed to oxygen and glucose deprivation (OGD). In gerbils, direct application of KYNA (100 nM, through reverse microdialysis in the hippocampus) completely prevented the increase in Glu output induced by transient (5 min) occlusion of the carotids. In rat hippocampal slices exposed for 30 min to OGD, KMO inhibitors (m-nitrobenzoyl)-alanine (mNBA, 30-100 microM) or 3,4-dimethoxy-[-N-4-(nitrophenyl)thiazol-2yl]-benzenesulfonamide (Ro 61-8048, 1-10 microM) reduced post-ischemic neuronal death and increased KYNA concentrations in the incubation medium. KYNA may antagonize glycineb or alpha7 nicotinic acetylcholine receptors but the concentrations in the incubation medium never reached values that could efficiently antagonize receptor function. On the contrary, 3-HK (1-10 microM) added to slices exposed to OGD in the presence of KMO inhibitors completely prevented the neuroprotective effects of the inhibitors. Our findings suggest that KMO inhibitors reduce OGD-induced pyramidal cell death by decreasing 3-HK (and possibly QUIN) synthesis.
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Cosgrove, J W; Brown, I R
1984-05-01
An initiating cell-free protein synthesis system derived from brain was utilized to demonstrate that the intravenous injection of D-lysergic acid diethylamide (LSD) to rabbits resulted in a lesion at the initiation stage of brain protein synthesis. Three inhibitors of initiation, edeine, poly(I), and aurintricarboxylic acid were used to demonstrate a reduction in initiation-dependent amino acid incorporation in the brain cell-free system. One hour after LSD injection, there was also a measurable decrease in the formation of 40S and 80S initiation complexes in vitro, using either [35S]methionine or [35S]Met-tRNAf. Analysis of the methionine pool size after LSD administration indicated there was no change in methionine levels. Analysis of the formation of initiation complexes in the brain cell-free protein synthesis system prepared 6 h after LSD administration indicated that there was a return to control levels at this time. The effects of LSD on steps in the initiation process are thus reversible.
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Mechanism of Formation of Li 7 P 3 S 11 Solid Electrolytes through Liquid Phase Synthesis
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wang, Yuxing; Lu, Dongping; Bowden, Mark
Crystalline Li7P3S11 is a promising solid electrolyte for all solid state lithium/lithium ion batteries. A controllable liquid phase synthesis of Li7P3S11 is more desirable compared to conventional mechanochemical synthesis, but recent attempts suffer from reduced ionic conductivities. Here we elucidate the formation mechanism of crystalline Li7P3S11 synthesized in the liquid phase (acetonitrile, or ACN). We conclude that the crystalline Li7P3S11 forms through a two-step reaction: 1) formation of solid Li3PS4∙ACN and amorphous Li2S∙P2S5 phases in the liquid phase; 2) solid-state conversion of the two phases. The implication of this two-step reaction mechanism to the morphology control and the transport propertiesmore » of liquid phase synthesized Li7P3S11 is identified and discussed.« less
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New halogenated phenylcoumarins as tyrosinase inhibitors.
Matos, Maria João; Santana, Lourdes; Uriarte, Eugenio; Delogu, Giovanna; Corda, Marcella; Fadda, Maria Benedetta; Era, Benedetta; Fais, Antonella
2011-06-01
With the aim to find out structural features for the tyrosinase inhibitory activity, in the present communication we report the synthesis and pharmacological evaluation of a new series of phenylcoumarin derivatives with different number of hydroxyl or ether groups and bromo substituent in the scaffold. The synthesized compounds 5-12 were evaluated as mushroom tyrosinase inhibitors showing, two of them, lower IC(50) than the umbelliferone. Compound 12 (IC(50)=215 μM) is the best tyrosinase inhibitor of this series. Copyright © 2011 Elsevier Ltd. All rights reserved.
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Cyclooxygenase inhibitors are potent sensitizers of prostate tumours to hyperthermia and radiation.
Asea, A; Mallick, R; Lechpammer, S; Ara, G; Teicher, B A; Fiorentino, S; Stevenson, M A; Calderwood, S K
2001-01-01
It has previously been demonstrated that hyperthermia can activate prostaglandin synthesis and that prostaglandins are protective against hyperthermia. This study examined the use of inhibitors of prostaglandin synthesis on the response of prostate tumours to hyperthermia. The non-steroidal anti-inflammatory drugs (NSAID) ibuprofen and sulindac, known cyclooxygenase inhibitors that inhibit prostaglandin production, were effective hyperthermia sensitizers and augmented growth delay of DU-145 and PC-3 prostate tumours to combined radiation and hyperthermia treatment protocols. Pre-treatment of mice with ibuprofen and sulindac at hyperthermia sensitizing doses resulted in significant (p < 0.01) inhibition of hyperthemia-induced serum prostaglandin E2. These findings indicate that NSAID may have both sensitizing effects on prostate tumour growth and may function by inhibiting prostaglandin synthesis.
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Gautam, Raju; Jachak, Sanjay M; Kumar, Vivek; Mohan, C Gopi
2011-03-15
Stellatin (4), isolated from Dysophylla stellata is a cyclooxygenase (COX) inhibitor. The present study reports the synthesis and biological evaluation of new stellatin derivatives for COX-1, COX-2 inhibitory and anti-inflammatory activities. Eight derivatives showed more pronounced COX-2 inhibition than stellatin and, 17 and 21 exhibited the highest COX-2 inhibition. They also exhibited the significant anti-inflammatory activity in TPA-induced mouse ear edema assay and their anti-inflammatory effects were more than that of stellatin and indomethacin at 0.5mg/ear. The derivatives were further evaluated for antioxidant activity wherein 16 and 17 showed potent free radical scavenging activity against DPPH and ABTS radicals. Molecular docking study revealed the binding orientations of stellatin and its derivatives into the active sites of COX-1 and COX-2 and thereby helps to design the potent inhibitors. Copyright © 2011 Elsevier Ltd. All rights reserved.
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Hofmann, Sarah; Cherkasova, Valeria; Bankhead, Peter; Bukau, Bernd; Stoecklin, Georg
2012-01-01
Cells respond to different types of stress by inhibition of protein synthesis and subsequent assembly of stress granules (SGs), cytoplasmic aggregates that contain stalled translation preinitiation complexes. Global translation is regulated through the translation initiation factor eukaryotic initiation factor 2α (eIF2α) and the mTOR pathway. Here we identify cold shock as a novel trigger of SG assembly in yeast and mammals. Whereas cold shock–induced SGs take hours to form, they dissolve within minutes when cells are returned to optimal growth temperatures. Cold shock causes eIF2α phosphorylation through the kinase PERK in mammalian cells, yet this pathway is not alone responsible for translation arrest and SG formation. In addition, cold shock leads to reduced mitochondrial function, energy depletion, concomitant activation of AMP-activated protein kinase (AMPK), and inhibition of mTOR signaling. Compound C, a pharmacological inhibitor of AMPK, prevents the formation of SGs and strongly reduces cellular survival in a translation-dependent manner. Our results demonstrate that cells actively suppress protein synthesis by parallel pathways, which induce SG formation and ensure cellular survival during hypothermia. PMID:22875991
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Preparation of ubiquitin-conjugated proteins using an insect cell-free protein synthesis system.
Suzuki, Takashi; Ezure, Toru; Ando, Eiji; Nishimura, Osamu; Utsumi, Toshihiko; Tsunasawa, Susumu
2010-01-01
Ubiquitination is one of the most significant posttranslational modifications (PTMs). To evaluate the ability of an insect cell-free protein synthesis system to carry out ubiquitin (Ub) conjugation to in vitro translated proteins, poly-Ub chain formation was studied in an insect cell-free protein synthesis system. Poly-Ub was generated in the presence of Ub aldehyde (UA), a de-ubiquitinating enzyme inhibitor. In vitro ubiquitination of the p53 tumor suppressor protein was also analyzed, and p53 was poly-ubiquitinated when Ub, UA, and Mdm2, an E3 Ub ligase (E3) for p53, were added to the in vitro reaction mixture. These results suggest that the insect cell-free protein synthesis system contains enzymatic activities capable of carrying out ubiquitination. CBB-detectable ubiquitinated p53 was easily purified from the insect cell-free protein synthesis system, allowing analysis of the Ub-conjugated proteins by mass spectrometry (MS). Lys 305 of p53 was identified as one of the Ub acceptor sites using this strategy. Thus, we conclude that the insect cell-free protein synthesis system is a powerful tool for studying various PTMs of eukaryotic proteins including ubiqutination presented here.
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Aurintricarboxylic acid is a potent inhibitor of phosphofructokinase.
McCune, S A; Foe, L G; Kemp, R G; Jurin, R R
1989-01-01
Aurintricarboxylic acid (ATA) was found to be a very potent inhibitor of purified rabbit liver phosphofructokinase (PFK), giving 50% inhibition at 0.2 microM. The inhibition was in a manner consistent with interaction at the citrate-inhibitory site of the enzyme. The data suggest that inhibition of PFK by ATA was not due to denaturation of the enzyme or the irreversible binding of inhibitor, since the inhibition could be reversed by addition of allosteric activators of PFK, i.e. fructose 2,6-bisphosphate or AMP. Two other tricarboxylic acids, agaric acid and (-)-hydroxycitrate, were found to inhibit PFK. ATA at much higher concentrations (500 microM) was shown to inhibit fatty acid synthesis from endogenous glycogen in rat hepatocytes; however, protein synthesis was not altered. PMID:2525029
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Krieger, Viktoria; Hamacher, Alexandra; Gertzen, Christoph G W; Senger, Johanna; Zwinderman, Martijn R H; Marek, Martin; Romier, Christophe; Dekker, Frank J; Kurz, Thomas; Jung, Manfred; Gohlke, Holger; Kassack, Matthias U; Hansen, Finn K
2017-07-13
In this work, we report the multicomponent synthesis of a focused histone deacetylase (HDAC) inhibitor library with peptoid-based cap groups and different zinc-binding groups. All synthesized compounds were tested in a cellular HDAC inhibition assay and an MTT assay for cytotoxicity. On the basis of their noteworthy activity in the cellular HDAC assays, four compounds were further screened for their inhibitory activity against recombinant HDAC1-3, HDAC6, and HDAC8. All four compounds showed potent inhibition of HDAC1-3 as well as significant inhibition of HDAC6 with IC 50 values in the submicromolar concentration range. Compound 4j, the most potent HDAC inhibitor in the cellular HDAC assay, revealed remarkable chemosensitizing properties and enhanced the cisplatin sensitivity of the cisplatin-resistant head-neck cancer cell line Cal27CisR by almost 7-fold. Furthermore, 4j almost completely reversed the cisplatin resistance in Cal27CisR. This effect is related to a synergistic induction of apoptosis as seen in the combination of 4j with cisplatin.
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Modulation of Platelet Activation and Thrombus Formation Using a Pan-PI3K Inhibitor S14161
Ren, Lijie; Liu, Xiaohui; Wang, Qi; He, Sudan; Wu, Qingyu; Hu, Hu; Mao, Xinliang; Zhu, Li
2014-01-01
The phosphatidylinositol 3–kinase (PI3K) signaling pathway is critical in modulating platelet functions. In the present study, we evaluated the effect of S14161, a recently identified pan-class I PI3K inhibitor, on platelet activation and thrombus formation. Results showed that S14161 inhibited human platelet aggregation induced by collagen, thrombin, U46619, and ADP in a dose-dependent manner. Flow cytometric studies showed that S14161 inhibited convulxin- or thrombin-induced P-selectin expression and fibrinogen binding of single platelet. S14161 also inhibited platelet spreading on fibrinogen and clot retraction, processes mediated by outside-in signaling. Using a microfluidic chamber we demonstrated that S14161 decreased platelet adhesion on collagen-coated surface by about 80%. Western blot showed that S14161 inhibited phosphorylation of Akt at both Ser473 and Thr308 sites, and GSK3β at Ser9 in response to collagen, thrombin, or U46619. Comparable studies showed that S14161 has a higher potential bioavailability than LY294002, a prototypical inhibitor of pan-class I PI3K. Finally, the effects of S14161 on thrombus formation in vivo were measured using a ferric chloride-induced carotid artery injury model in mice. The intraperitoneal injection of S14161 (2 mg/kg) to male C57BL/6 mice significantly extended the first occlusion time (5.05±0.99 min, n = 9) compared to the vehicle controls (3.72±0.95 min, n = 8) (P<0.05), but did not prolong the bleeding time (P>0.05). Taken together, our data showed that S14161 inhibits platelet activation and thrombus formation without significant bleeding tendency and toxicity, and considering its potential higher bioavailability, it may be developed as a novel therapeutic agent for the prevention of thrombotic disorders. PMID:25115838
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NASA Astrophysics Data System (ADS)
Mohammadi, Ali A.; Taheri, Salman; Amouzegar, Ali; Ahdenov, Reza; Halvagar, Mohammad Reza; Sadr, Ahmad Shahir
2017-07-01
An efficient one-pot, catalyst-free, and four-components procedure for the synthesis of novel 10b-hydroxy-4-nitro-5-phenyl-2,3,5,5a-tetrahydro-1H-imidazo[1,2-a]indeno[2,1-e]pyridin-6(10bH)-one derivatives from corresponding diamine, nitro ketene dithioacetal, aldehydes and 1,3-indandione in ethanol has been achieved upon a Knoevenagel condensation-Michael addition-tautomerism-cyclisation sequence. All the newly synthesized compounds were screened for molecular docking studies. Molecular docking studies were carried out using the crystal structure of HIV protease enzyme. Some of the compounds obtain minimum binding energy and good affinity toward the active pocket of HIV protease enzyme in compare with Saquinavir as a standard HIV protease inhibitor.
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PROFLAVINE INHIBITION OF VACCINIA VIRUS SYNTHESIS.
BUBEL, H C; WOLFF, D A
1965-04-01
Bubel, H. Curt (University of Cincinnati College of Medicine, Cincinnati, Ohio), and David A. Wolff. Proflavine inhibition of vaccinia virus synthesis. J. Bacteriol. 89:977-983. 1965.-The synthesis of vaccinia virus, hemagglutinin, and blocking antigen, as well as the development of cytopathic effects, were inhibited by low concentrations of proflavine. This inhibitor did not exert a selective effect on any particular portion of the virus synthetic cycle. Proflavine added to infected KB cells during the eclipse period or later stages of virus maturation rapidly arrested further production of infectious virus and virus-related products. Suppression of virus synthesis was completely reversible, indicating that permanent damage to the virus synthetic mechanism did not result from a transient exposure to proflavine. Photosensitization of maturating vaccinia virus by subinhibiting concentrations of proflavine suggested an interaction of the inhibitor with viral nucleic acid.
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Davis, Tyler A.
2012-01-01
The first highly diastereo- and enantioselective additions of aryl nitromethane pronucleophiles to aryl aldimines are described. Identification of an electron rich chiral Bis(Amidine) catalyst for this aza-Henry variant was key to this development, leading ultimately to differentially protected cis-stilbene diamines in two steps. This method then became the lynchpin for an enantioselective synthesis of (–)-Nutlin-3 (Hoffmann-LaRoche), a potent cis-imidazoline small molecule inhibitor of p53-MDM2 used extensively as a probe of cell biology and currently in drug development. PMID:22708054
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NASA Astrophysics Data System (ADS)
Nazar, Muhammad Faizan; Abdullah, Muhammad Imran; Badshah, Amir; Mahmood, Asif; Rana, Usman Ali; Khan, Salah Ud-Din
2015-04-01
The chalcones core in compounds is advantageously chosen effective synthons, which offer exciting perspectives in biological and pharmacological research. The present study reports the successful development of eight new cyclohexenone based anti-reverse transcriptase analogous using rational drug design synthesis principles. These new cyclohexenone derivatives (CDs) were synthesized by following a convenient route of Robinson annulation, and the molecular structure of these CDs were later confirmed by various analytical techniques such as 1H NMR, 13C NMR, FT-IR, UV-Vis spectroscopy and mass spectrometry. All the synthesized compounds were screened theoretically and experimentally against reverse transcriptase (RT) and found potentially active reverse transcriptase (RT) inhibitors. Of the compounds studied, the compound 2FC4 showed high interaction with RT at non-nucleoside binding site, contributing high free binding energy (ΔG -8.01 Kcal) and IC50 (0.207 μg/ml), respectively. Further results revealed that the compounds bearing more halogen groups, with additional hydrophobic character, offered superior anti-reverse transcriptase activity as compared to rest of compounds. It is anticipate that the present study would be very useful for the selection of potential reverse transcriptase inhibitors featuring inclusive pharmacological profiles.
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Muzaffar, Saima; Shukla, Nilima; Srivastava, Amit; Angelini, Gianni D; Jeremy, Jamie Y
2005-09-01
Acute respiratory distress syndrome (ARDS) is associated with increased superoxide (O(2)(*-)) formation in the pulmonary vasculature and negation of the bioavailability of nitric oxide (NO). Since NO inhibits NADPH oxidase expression through a cyclic GMP-mediated mechanism, sildenafil, a type V phosphodiesterase inhibitor, may be therapeutically effective in ARDS through an augmentation of NO-mediated inhibition of NADPH oxidase. Therefore, the effect of sildenafil citrate and NO-donating sildenafil (NCX 911) on O(2)(*-) formation and gp91(phox) (active catalytic subunit of NADPH oxidase) expression was investigated in cultured porcine pulmonary artery endothelial cells (PAECs). PAECs were incubated with 10 nM TXA(2) analogue, 9,11-dideoxy-9alpha,11alpha-methanoepoxy-prostaglandin F(2alpha) (U46619) (+/-sildenafil or NCX 911), for 16 h and O(2)(*-) formation measured spectrophometrically and gp91(phox) using Western blotting. The role of the NO-cGMP axis was studied using morpholinosydnonimine hydrochloride (SIN-1), the diethylamine/NO complex (DETA-NONOate), the guanylyl cyclase inhibitor, 1H-{1,2,4}oxadiazolo{4,3-a}quinoxalin-1-one (ODQ), and the protein kinase G inhibitor, 8-bromoguanosine-3',5'-cyclic monophosphorothioate, Rp-isomer (Rp-8-Br-cGMPS). NO release was studied using a fluorescence assay and O(2)(*-)-NO interactions by measuring nitrites. After a 16-h incubation with 10 nM U46619, both NCX 911 and sildenafil elicited a concentration-dependent inhibition of O(2)(*-) formation and gp91(phox) expression, NCX 911 being more potent (IC(50); 0.26 nM) than sildenafil citrate (IC(50); 1.85 nM). These inhibitory effects were reversed by 1 microM ODQ and 10 microM Rp-8-Br-cGMPS. NCX 911 stimulated the formation of cGMP in PAECs and generated NO in a cell-free system to a greater degree than sildenafil citrate. The inhibitory effect of sildenafil was augmented by 1 muM SIN-1 and blocked partially by the eNOS inhibitor 10 microM N(5)-(1-iminoethyl)-ornithine (L
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Novel amide-based inhibitors of inosine 5'-monophosphate dehydrogenase.
Watterson, Scott H; Liu, Chunjian; Dhar, T G Murali; Gu, Henry H; Pitts, William J; Barrish, Joel C; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Hollenbaugh, Diane L; Iwanowicz, Edwin J
2002-10-21
A series of novel amide-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are described.
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Fakas, Stylianos; Konstantinou, Chrysanthos; Carman, George M.
2011-01-01
In the yeast Saccharomyces cerevisiae, triacylglycerol mobilization for phospholipid synthesis occurs during growth resumption from stationary phase, and this metabolism is essential in the absence of de novo fatty acid synthesis. In this work, we provide evidence that DGK1-encoded diacylglycerol kinase activity is required to convert triacylglycerol-derived diacylglycerol to phosphatidate for phospholipid synthesis. Cells lacking diacylglycerol kinase activity (e.g. dgk1Δ mutation) failed to resume growth in the presence of the fatty acid synthesis inhibitor cerulenin. Lipid analysis data showed that dgk1Δ mutant cells did not mobilize triacylglycerol for membrane phospholipid synthesis and accumulated diacylglycerol. The dgk1Δ phenotypes were partially complemented by preventing the formation of diacylglycerol by the PAH1-encoded phosphatidate phosphatase and by channeling diacylglycerol to phosphatidylcholine via the Kennedy pathway. These observations, coupled to an inhibitory effect of dioctanoyl-diacylglycerol on the growth of wild type cells, indicated that diacylglycerol kinase also functions to alleviate diacylglycerol toxicity. PMID:21071438
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Context-Dependent Antagonism between Akt Inhibitors and Topoisomerase Poisons
Gálvez-Peralta, Marina; Flatten, Karen S.; Loegering, David A.; Peterson, Kevin L.; Schneider, Paula A.; Erlichman, Charles
2014-01-01
Signaling through the phosphatidylinositol-3 kinase (PI3K)/Akt pathway, which is aberrantly activated in >50% of carcinomas, inhibits apoptosis and contributes to drug resistance. Accordingly, several Akt inhibitors are currently undergoing preclinical or early clinical testing. To examine the effect of Akt inhibition on the activity of multiple widely used classes of antineoplastic agents, human cancer cell lines were treated with the Akt inhibitor A-443654 [(2S)-1-(1H-indol-3-yl)-3-[5-(3-methyl-2H-indazol-5-yl)pyridin-3-yl]oxypropan-2-amine; ATP-competitive] or MK-2206 (8-[4-(1-aminocyclobutyl)phenyl]-9-phenyl-2H-[1,2,4]triazolo[3,4-f][1,6]naphthyridin-3-one;dihydrochloride; allosteric inhibitor) or with small interfering RNA (siRNA) targeting phosphoinositide-dependent kinase 1 (PDK1) along with cisplatin, melphalan, camptothecin, or etoposide and assayed for colony formation. Surprisingly different results were observed when Akt inhibitors were combined with different drugs. Synergistic effects were observed in multiple cell lines independent of PI3K pathway status when A-443654 or MK-2206 was combined with the DNA cross-linking agents cisplatin or melphalan. In contrast, effects of the Akt inhibitors in combination with camptothecin or etoposide were more complicated. In HCT116 and DLD1 cells, which harbor activating PI3KCA mutations, A-443654 over a broad concentration range enhanced the effects of camptothecin or etoposide. In contrast, in cell lines lacking activating PI3KCA mutations, partial inhibition of Akt signaling synergized with camptothecin or etoposide, but higher A-443654 or MK-2206 concentrations (>80% inhibition of Akt signaling) or PDK1 siRNA antagonized the topoisomerase poisons by diminishing DNA synthesis, a process that contributes to effective DNA damage and killing by these agents. These results indicate that the effects of combining inhibitors of the PI3K/Akt pathway with certain classes of chemotherapeutic agents might be more
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Context-dependent antagonism between Akt inhibitors and topoisomerase poisons.
Gálvez-Peralta, Marina; Flatten, Karen S; Loegering, David A; Peterson, Kevin L; Schneider, Paula A; Erlichman, Charles; Kaufmann, Scott H
2014-05-01
Signaling through the phosphatidylinositol-3 kinase (PI3K)/Akt pathway, which is aberrantly activated in >50% of carcinomas, inhibits apoptosis and contributes to drug resistance. Accordingly, several Akt inhibitors are currently undergoing preclinical or early clinical testing. To examine the effect of Akt inhibition on the activity of multiple widely used classes of antineoplastic agents, human cancer cell lines were treated with the Akt inhibitor A-443654 [(2S)-1-(1H-indol-3-yl)-3-[5-(3-methyl-2H-indazol-5-yl)pyridin-3-yl]oxypropan-2-amine; ATP-competitive] or MK-2206 (8-[4-(1-aminocyclobutyl)phenyl]-9-phenyl-2H-[1,2,4]triazolo[3,4-f][1,6]naphthyridin-3-one;dihydrochloride; allosteric inhibitor) or with small interfering RNA (siRNA) targeting phosphoinositide-dependent kinase 1 (PDK1) along with cisplatin, melphalan, camptothecin, or etoposide and assayed for colony formation. Surprisingly different results were observed when Akt inhibitors were combined with different drugs. Synergistic effects were observed in multiple cell lines independent of PI3K pathway status when A-443654 or MK-2206 was combined with the DNA cross-linking agents cisplatin or melphalan. In contrast, effects of the Akt inhibitors in combination with camptothecin or etoposide were more complicated. In HCT116 and DLD1 cells, which harbor activating PI3KCA mutations, A-443654 over a broad concentration range enhanced the effects of camptothecin or etoposide. In contrast, in cell lines lacking activating PI3KCA mutations, partial inhibition of Akt signaling synergized with camptothecin or etoposide, but higher A-443654 or MK-2206 concentrations (>80% inhibition of Akt signaling) or PDK1 siRNA antagonized the topoisomerase poisons by diminishing DNA synthesis, a process that contributes to effective DNA damage and killing by these agents. These results indicate that the effects of combining inhibitors of the PI3K/Akt pathway with certain classes of chemotherapeutic agents might be more
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Storm, Mie Møller, E-mail: mmst@dtu.dk; Johnsen, Rune E.; Norby, Poul
2016-08-15
Graphene oxide (GO) and reduced graphene oxide (rGO) are important materials in a wide range of fields. The modified Hummers methods, for synthesizing GO, and subsequent thermal reduction to rGO, are often employed for production of rGO. However, the mechanism behinds these syntheses methods are still unclear. We present an in situ X-ray diffraction study of the synthesis of GO and thermal reduction of GO. The X-ray diffraction revealed that the Hummers method includes an intercalation state and finally formation of additional crystalline material. The formation of GO is observed during both the intercalation and the crystallization stage. During thermalmore » reduction of GO three stages were observed: GO, a disordered stage, and the rGO stage. The appearance of these stages depends on the heating ramp. The aim of this study is to provide deeper insight into the chemical and physical processes during the syntheses. - Graphical abstract: In situ X-ray diffraction results for of the modified Hummers synthesis and the thermal reduction of graphene oxide, revealing three stages for both syntheses as well as new GO diffraction peaks and unidentified crystalline material for the Hummers synthesis and a disordered stage for the thermal reduction of graphene oxide. Display Omitted - Highlights: • Hummers synthesis consists of three stages: dissolution, intercalation and crystal. • GO is produced early on during the synthesis and display new diffraction peaks. • An unidentified triclinic phase is observed for the Hummers synthesis. • Thermal reduction of GO display three stages: GO, a disordered stage and rGO. • In situ XRD indicate reformation of rGO even for fast heated thermal reduction.« less
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The existence of imidazoline corrosion inhibitors
DOE Office of Scientific and Technical Information (OSTI.GOV)
Martin, J.A.; Valone, F.W.
1985-05-01
Spectroscopic methods, i.e., Fourier transform infrared (FT-IR), carbon-13 nuclear magnetic reasonance (/sup 13/C NMR), and ultraviolet (UV) spectroscopy, were used to investigate the actual chemical composition of oilfield corrosion inhibitors. Inhibitor formulations consisting of an amide or imidazoline reacted with a dimer-trimer acid, along with an ethoxylated surfactant and an aromatic solvent, were used for these studies. /sup 13/C NMR and FT-IR spectra of these inhibitors, as well as spectra of pure imidazolines, showed that the imidazoline functional group was fairly rapidly hydrolyzed to the amide form. For instance, in FT-IR studies, the imine functional group decreased in intensity asmore » a function of time. Coincident with this was an increase in the intensities of the vibrational resonances attributed to the amide functionality. The relative molar ratio of imidazoline to amide in a corrosion inhibitor could be calculated via UV spectroscopy. Within a 20 day interval after inhibitor synthesis, this ratio decreased by a factor greater than 20. These results, as well as a discussion of their economic impact on oilfield corrosion inhibitor formulation, are presented in this paper.« less
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Design, Synthesis and Inhibitory Activity of Photoswitchable RET Kinase Inhibitors
NASA Astrophysics Data System (ADS)
Ferreira, Rubén; Nilsson, Jesper R.; Solano, Carlos; Andréasson, Joakim; Grøtli, Morten
2015-05-01
REarranged during Transfection (RET) is a transmembrane receptor tyrosine kinase required for normal development and maintenance of neurons of the central and peripheral nervous systems. Deregulation of RET and hyperactivity of the RET kinase is intimately connected to several types of human cancers, most notably thyroid cancers, making it an attractive therapeutic target for small-molecule kinase inhibitors. Novel approaches, allowing external control of the activity of RET, would be key additions to the signal transduction toolbox. In this work, photoswitchable RET kinase inhibitors based on azo-functionalized pyrazolopyrimidines were developed, enabling photonic control of RET activity. The most promising compound displays excellent switching properties and stability with good inhibitory effect towards RET in cell-free as well as live-cell assays and a significant difference in inhibitory activity between its two photoisomeric forms. As the first reported photoswitchable small-molecule kinase inhibitor, we consider the herein presented effector to be a significant step forward in the development of tools for kinase signal transduction studies with spatiotemporal control over inhibitor concentration in situ.
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Synthesis of the 2-methylene analogue of the HRV 3C protease inhibitor thysanone (2-carbathysanone).
Schünemann, Katrin; Furkert, Daniel P; Choi, Eun Cho; Connelly, Stephen; Fraser, John D; Sperry, Jonathan; Brimble, Margaret A
2014-02-14
The Human Rhinovirus (HRV) is the major aetiological agent for the common cold, for which only symptomatic treatment is available. HRV maturation and replication is entirely dependent on the activity of a virally encoded 3C protease that represents an attractive target for the development of therapeutics to treat the common cold. Herein we report the synthesis and biological evaluation of the 2-methylene analogue of the HRV 3C protease inhibitor (-)-thysanone (1) namely 2-carbathysanone (2), in an attempt to decipher the structural features in the natural product that are responsible for the 3C protease activity. 2-Carbathysanone (2) (and related analogues (±)-cis-23, (±)-cis-30, (±)-31) did not inhibit HRV 3C protease, indicating that the lactol functionality present in (-)-thysanone (1) is a critical structural feature required for inhibition.
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Karbowski, M; Kurono, C; Wozniak, M; Ostrowski, M; Teranishi, M; Soji, T; Wakabayashi, T
1999-02-04
Toxic effects of chloramphenicol, an antibiotic inhibitor of mitochondrial protein synthesis, on rat liver derived RL-34 cell line were completely blocked by a combined treatment with substances endowed with direct or indirect antioxidant properties. A stable, nitroxide free radical scavenger, 4-hydroxy-2,2,6, 6-tetramethylpiperidine-1-oxyl, and a protein synthesis inhibitor, cycloheximide, suppressed in a similar manner the following manifestations of the chloramphenicol cytotoxicity: (1) Oxidative stress state as evidenced by FACS analysis of cells loaded with carboxy-dichlorodihydrofluorescein diacetate and Mito Tracker CMTH2MRos; (2) megamitochondria formation detected by staining of mitochondria with MitoTracker CMXRos under a laser confocal microscopy and electron microscopy; (3) apoptotic changes of the cell detected by the phase contrast microscopy, DNA laddering analysis and cell cycle analysis. Since increases of ROS generation in chloramphenicol-treated cells were the first sign of the chloramphenicol toxicity, we assume that oxidative stress state is a mediator of above described alternations of RL-34 cells including MG formation. Pretreatment of cells with cycloheximide or 4-hydroxy-2,2, 6,6-tetramethylpiperidine-1-oxyl, which is known to be localized into mitochondria, inhibited the megamitochondria formation and succeeding apoptotic changes of the cell. Protective effects of cycloheximide, which enhances the expression of Bcl-2 protein, may further confirm our hypothesis that the megamitochondria formation is a cellular response to an increased ROS generation and raise a possibility that antiapoptotic action of the drug is exerted via the protection of the mitochondria functions.
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Nie, Rong-Zu; Zhu, Wei; Peng, Jin-Ming; Ge, Zhen-Zhen; Li, Chun-Mei
2016-06-01
Because fibrillary protein aggregates is regarded to be closely associated with many diseases such as Alzheimer's disease, diabetes, and Parkinson's disease, growing interest and researches have been focused on finding potential fibrillation inhibitors. In the present study, the inhibitory effects of epigallocatechin-3-gallate (EGCG) and A-type dimeric epigallocatechin-3-gallate (A-type EGCG dimer) on the formation of insulin fibrillation were compared by multi-dimensional approaches including thioflavin-T (ThT) fluorescence assay, 1-anilinonaphthalene-8-sulfonic (ANS) fluorescence assay, dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and circular dichroism (CD) spectroscopy. Our results confirmed that A-type EGCG dimer is a more potent inhibitor against the formation of bovine insulin amyloid fibril than EGCG. In addition, A-type EGCG dimer could not only inhibit insulin amyloid fibril formation, but also change the aggregation pathway and induce bovine insulin into amorphous aggregates. The results of the present study may provide a new guide on finding novel anti-amyloidogenic agents. Copyright © 2016 Elsevier B.V. and Société française de biochimie et biologie Moléculaire (SFBBM). All rights reserved.
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Gálvez, Jaime; Polo, Stivens; Insuasty, Braulio; Gutiérrez, Margarita; Cáceres, Daniela; Alzate-Morales, Jans H; De-la-Torre, Pedro; Quiroga, Jairo
2018-03-07
Given the wide spectrum of biological uses of pyrazolo[1,5-c]quinazoline and spiro-quinazoline derivatives as anticancer, anti-inflammatory analgesic agents, and their therapeutic applications in neurodegenerative disorders, it is compulsory to find easy, efficient, and simple methods to obtain and chemically diversify these families of compounds, thereby improving their biological applications. In this paper, we report the design and eco-friendly two-step synthesis of novel, fused spiro-pyrazolo[1,5-c]quinazoline derivatives as cholinesterase inhibitors. In addition, we studied their protein-ligand interactions via molecular docking and MM/GBSA calculations for a further rational design of more potent inhibitors. In first step, 2-(1H-pyrazol-5-yl)anilines were obtained through microwave (MW) assisted solvent-free/catalyst-free conditions and the second step involved the synthesis of the spiro-pyrazolo[1,5-c]quinazolines by a cyclocondensation reaction between 2-(1H-pyrazol-5-yl)anilines and cyclic ketones, or acetophenones, using stirring at room temperature. The compounds were obtained in high purity, good yields (50-97%), and at varying reaction times. The spiro-compounds were evaluated as acetylcholinesterase and butyrylcholinesterase inhibitors (AChEIs/BuChEIs) respectively, and the most potent compound exhibited a moderate AChE inhibitory activity (5f: IC 50 = 84 μM). Molecular docking studies indicated that the binding mode of the compound 5f share common characteristics with the galantamine/donepezil-AChE complexes. Moreover, free binding energy (ΔG) calculations showed a good agreement with the experimental biological activity values. Our theoretical results indicated that halogen bond interactions could be involved with differential potency of these compounds and provide a new starting point to design novel pyrazolo[1,5-c]quinazolines as new anti-Alzheimer agents. Copyright © 2018. Published by Elsevier Ltd.
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Proflavine Inhibition of Vaccinia Virus Synthesis
Bubel, H. Curt; Wolff, David A.
1965-01-01
Bubel, H. Curt (University of Cincinnati College of Medicine, Cincinnati, Ohio), and David A. Wolff. Proflavine inhibition of vaccinia virus synthesis. J. Bacteriol. 89:977–983. 1965.—The synthesis of vaccinia virus, hemagglutinin, and blocking antigen, as well as the development of cytopathic effects, were inhibited by low concentrations of proflavine. This inhibitor did not exert a selective effect on any particular portion of the virus synthetic cycle. Proflavine added to infected KB cells during the eclipse period or later stages of virus maturation rapidly arrested further production of infectious virus and virus-related products. Suppression of virus synthesis was completely reversible, indicating that permanent damage to the virus synthetic mechanism did not result from a transient exposure to proflavine. Photosensitization of maturating vaccinia virus by subinhibiting concentrations of proflavine suggested an interaction of the inhibitor with viral nucleic acid. PMID:14276124
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Tomassoli, Isabelle; Ismaili, Lhassane; Pudlo, Marc; de Los Ríos, Cristóbal; Soriano, Elena; Colmena, Inés; Gandía, Luis; Rivas, Luis; Samadi, Abdelouahid; Marco-Contelles, José; Refouvelet, Bernard
2011-01-01
The synthesis, biological evaluation, and molecular modeling of new 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxamides(4), 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carbohydrazide (6), and some hexahydropyrimido[5,4-c]quinoline-2,5-diones (9) produced earlier by our laboratory, as AChE/BuChE inhibitors, is described. From these analyses compound 4c resulted equipotent regarding the inhibition of cholinesterases'; inhibitors 6k, 9a, 9b were selective for AChE, whereas product 4d proved selective for BuChE. Docking analysis has been carry out in order to identify the binding mode in the active site, and to explain the observed selectivities. Only compound 9a has been shown to decrease K(+)-induced calcium signals in bovine chromaffin cells. Copyright © 2010 Elsevier Masson SAS. All rights reserved.
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Du, Guohui; Cao, Dongmei; Meng, Lingzheng
2017-05-01
The present study aimed to investigate the role and the molecular mechanisms underlying the effects of microRNA-21 (miR-21) on the proliferation, apoptosis and colony formation of cervical cancer cells, and to examine the role of miR-21 in mediating the sensitivity of cervical cancer cells to paclitaxel (PTX). Reverse transcription‑quantitative polymerase chain reaction was employed to determine the level of miR‑21 in various cervical cancer and normal cervical cells. The results revealed that the expression levels of miR-21 in cervical cancer cells were markedly higher when compared with normal cervical cells. Subsequently, a miR‑21 inhibitor or negative control (NC) was transfected into cervical cancer cells. Cell viability, colony formation and apoptosis were then analyzed using an MTT assay, crystal violet and Annexin V-fluorescein isothiocyanate/propidium iodide staining, respectively. The protein expression level of B-cell lymphoma‑2 (Bcl‑2), Bcl‑2‑associated X (Bax), programmed cell death 4 (PDCD4), survivin, c‑myc, phosphatase and tensin homolog (PTEN) and phosphorylated (p)‑AKT were determined by western blot analysis. The sensitivity of cervical cancer cells to PTX (25, 50 and 100 µg/ml) was characterized using an MTT assay. The results demonstrated that the miR-21 inhibitor promoted apoptosis of cervical cancer cells and suppressed their proliferation and colony formation when compared with the NC. In addition, the expression levels of Bcl‑2, survivin, c‑myc and p‑AKT were significantly downregulated in cells transfected with the miR‑21 inhibitor, whilst the expression levels of Bax, PDCD4 and PTEN were significantly upregulated. Furthermore, the miR‑21 inhibitor significantly enhanced the inhibition efficacy of PTX at a range of concentrations in cervical cancer cells. It was concluded that inhibition of miR‑21 suppressed cell proliferation and colony formation through regulating the PTEN/AKT pathway, and improved PTX
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Zha, Chuantao; Deng, Wenjia; Fu, Yan; Tang, Shuai; Lan, Xiaojing; Ye, Yan; Su, Yi; Jiang, Lei; Chen, Yi; Huang, Ying; Ding, Jian; Geng, Meiyu; Huang, Min; Wan, Huixin
2018-03-25
CDK4/6 pathway is an attractive chemotherapeutic target for antitumor drug discovery and development. Herein, we reported the structure-based design and synthesis of a series of novel tetrahydronaphthyridine analogues as selective CDK4/6 inhibitors. Compound 5 was identified as a hit and then systematically structure optimization study was conducted. These efforts led to compound 28, which exhibited excellent in vitro potencies against CDK4/6 enzymatic activity with high selectivity over CDK1, and against Colo-205 cell growth. The compound demonstrated favorable in vitro metabolic and robust mice pharmacokinetic properties. In Colo-205 xenograft models, compound 28 showed potent tumor growth inhibition with acceptable toxic effects, which could serve as a novel anticancer agent for further preclinical study. Copyright © 2018 Elsevier Masson SAS. All rights reserved.
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Chen, Yao; Zhu, Jie; Mo, Jun; Yang, Hongyu; Jiang, Xueyang; Lin, Hongzhi; Gu, Kai; Pei, Yuqiong; Wu, Liang; Tan, Renxiang; Hou, Jing; Chen, Jingyi; Lv, Yang; Bian, Yaoyao; Sun, Haopeng
2018-12-01
Small molecule cholinesterases inhibitor (ChEI) provides an effective therapeutic strategy to treat Alzheimer's disease (AD). Currently, the discovery of new ChEI with multi-target effect is still of great importance. Herein, we report the synthesis, structure-activity relationship study and biological evaluation of a series of tacrine-cinnamic acid hybrids as new ChEIs. All target compounds are evaluated for their in vitro cholinesterase inhibitory activities. The representatives which show potent activity on cholinesterase, are evaluated for the amyloid β-protein self-aggregation inhibition and in vivo assays. The optimal compound 19, 27, and 30 (human AChE IC 50 = 10.2 ± 1.2, 16.5 ± 1.7, and 15.3 ± 1.8 nM, respectively) show good performance in ameliorating the scopolamine-induced cognition impairment and preliminary safety in hepatotoxicity evaluation. These compounds deserve further evaluation for the development of new therapeutic agents against AD.
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Carpenedo, Raffaella; Meli, Elena; Peruginelli, Fiamma; Pellegrini-Giampietro, Domenico E; Moroni, Flavio
2002-09-01
Kynurenine 3-mono-oxygenase (KMO) inhibitors reduce 3-hydroxykynurenine (3-HK) and quinolinic acid (QUIN) neosynthesis and facilitate kynurenine metabolism towards kynurenic acid (KYNA) formation. They also reduce tissue damage in models of focal or transient global cerebral ischemia in vivo. We used organotypic hippocampal slice cultures exposed to oxygen and glucose deprivation (OGD) to investigate KMO mechanism(s) of neuroprotective activity. Exposure of the slices to 30 min of OGD caused CA1 pyramidal cell death and significantly decreased the amount of KYNA released in the incubation medium. The KMO inhibitors (m-nitrobenzoyl)-alanine (30-100 micro m) or 3,4-dimethoxy-[-N-4-(nitrophenyl)thiazol-2yl]-benzenesulfonamide (1-10 micro m) reduced post-ischemic neuronal death and increased KYNA concentrations in slice incubation media. The maximal concentration of KYNA detected in the incubation media of slices treated with KMO inhibitors was approximately 50 nm and was too low to efficiently interact with alpha7 nicotinic acetylcholine receptors or with the glycineb site of N-methyl-d-aspartate (NMDA) receptors. On the other hand, the addition of either 3-HK or QUIN (1-10 micro m) to OGD-exposed hippocampal slices prevented the neuroprotective activity of KMO inhibitors. Our results suggest that KMO inhibitors reduce the neuronal death found in the CA1 region of organotypic hippocampal slices exposed to 30 min of OGD by decreasing the local synthesis of 3-HK and QUIN.
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Design of Monoamine Reuptake Inhibitors: SSRIs, SNRIs and NRIs
NASA Astrophysics Data System (ADS)
Whitlock, Gavin A.; Andrews, Mark D.; Brown, Alan D.; Fish, Paul V.; Stobie, Alan; Wakenhut, Florian
This review will detail the medicinal chemistry involved in the design, synthesis and discovery of selective serotonin, noradrenaline reuptake inhibitors and dual serotonin/noradrenaline reuptake inhibitors. In particular, this review will focus exclusively on series and compounds which have been disclosed within the medicinal chemistry literature between January 2000 and June 2008. Background information on previously disclosed clinical agents, such as atomoxetine, milnacipran and reboxetine, is included for comparison purposes with more recently disclosed agents.
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Biosynthetic pathway of the phytohormone auxin in insects and screening of its inhibitors.
Suzuki, Hiroyoshi; Yokokura, Junpei; Ito, Tsukasa; Arai, Ryoma; Yokoyama, Chiaki; Toshima, Hiroaki; Nagata, Shinji; Asami, Tadao; Suzuki, Yoshihito
2014-10-01
Insect galls are abnormal plant tissues induced by galling insects. The galls are used for food and habitation, and the phytohormone auxin, produced by the insects, may be involved in their formation. We found that the silkworm, a non-galling insect, also produces an active form of auxin, indole-3-acetic acid (IAA), by de novo synthesis from tryptophan (Trp). A detailed metabolic analysis of IAA using IAA synthetic enzymes from silkworms indicated an IAA biosynthetic pathway composed of a three-step conversion: Trp → indole-3-acetaldoxime → indole-3-acetaldehyde (IAAld) → IAA, of which the first step is limiting IAA production. This pathway was shown to also operate in gall-inducing sawfly. Screening of a chemical library identified two compounds that showed strong inhibitory activities on the conversion step IAAld → IAA. The inhibitors can be efficiently used to demonstrate the importance of insect-synthesized auxin in gall formation in the future. Copyright © 2014 Elsevier Ltd. All rights reserved.
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Ertan-Bolelli, Tuğba; Musdal, Yaman; Bolelli, Kayhan; Yilmaz, Serap; Aksoy, Yasemin; Yildiz, Ilkay; Aki-Yalcin, Esin; Yalcin, Ismail
2014-05-01
Glutathione-S-transferases (GSTs) are enzymes involved in cellular detoxification by catalyzing the nucleophilic attack of glutathione (GSH) on the electrophilic center of numerous of toxic compounds and xenobiotics, including chemotherapeutic drugs. Human GST P1-1, which is known as the most prevalent isoform of the mammalian cytosolic GSTs, is overexpressed in many cancers and contributes to multidrug resistance by directly conjugating to chemotherapeutics. It is suggested that this resistance is related to the high expression of GST P1-1 in cancers, thereby contributing to resistance to chemotherapy. In addition, GSTs exhibit sulfonamidase activity, thereby catalyzing the GSH-mediated hydrolysis of sulfonamide bonds. Such reactions are of interest as potential tumor-directed prodrug activation strategies. Herein we report the design and synthesis of some novel sulfonamide-containing benzoxazoles, which are able to inhibit human GST P1-1. Among the tested compounds, 2-(4-chlorobenzyl)-5-(4-nitrophenylsulfonamido)benzoxazole (5 f) was found as the most active hGST P1-1 inhibitor, with an IC50 value of 10.2 μM, showing potency similar to that of the reference drug ethacrynic acid. Molecular docking studies performed with CDocker revealed that the newly synthesized 2-substituted-5-(4-nitrophenylsulfonamido)benzoxazoles act as catalytic inhibitors of hGST P1-1 by binding to the H-site and generating conjugates with GSH to form S-(4-nitrophenyl)GSH (GS-BN complex) via nucleophilic aromatic substitution reaction. The 4-nitrobenzenesulfonamido moiety at position 5 of the benzoxazole ring is essential for binding to the H-site and for the formation of the GST-mediated GSH conjugate. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Kehls, N E; Herrmann, K; Berking, S
1999-01-01
The polyps of Cassiopea andromeda produce spindle shaped, freely swimming buds which do not develop a head (a mouth opening surrounded by tentacles) and a foot (a sticky plate at the opposite end) until settlement to a suited substrate. The buds, therewith, look very similar to the planula larvae produced in sexual reproduction. With respect to both, buds and planulae, several peptides and the phorbolester TPA have been found to induce the transformation into a polyp. Here it is shown that cantharidin, a serine/threonine protein phosphatase inhibitor, induces head and foot formation in buds very efficiently in a 30 min treatment, the shortest yet known efficient treatment. Some resultant polyps show malformations which indicate that a bud is ordinary polyp tissue in which preparatory steps of head and foot formation mutually block each other from proceeding. Various compounds related to the transfer of methyl groups have been shown to affect head and foot formation in larvae of the hydrozoon Hydractinia echinata. These compounds including methionine, homocysteine, trigonelline, nicotinic acid and cycloleucine are shown to also interfere with the initiation of the processes which finally lead to head and foot formation in buds of Cassiopea andromeda.
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2015-01-01
Quantifying glycogen synthase kinase-3 (GSK-3) activity in vivo using positron emission tomography (PET) imaging is of interest because dysregulation of GSK-3 is implicated in numerous diseases and neurological disorders for which GSK-3 inhibitors are being considered as therapeutic strategies. Previous PET radiotracers for GSK-3 have been reported, but none of the published examples cross the blood–brain barrier. Therefore, we have an ongoing interest in developing a brain penetrating radiotracer for GSK-3. To this end, we were interested in synthesis and preclinical evaluation of [11C]SB-216763, a high-affinity inhibitor of GSK-3 (Ki = 9 nM; IC50 = 34 nM). Initial radiosyntheses of [11C]SB-216763 proved ineffective in our hands because of competing [3 + 3] sigmatropic shifts. Therefore, we have developed a novel one-pot two-step synthesis of [11C]SB-216763 from a 2,4-dimethoxybenzyl-protected maleimide precursor, which provided high specific activity [11C]SB-216763 in 1% noncorrected radiochemical yield (based upon [11C]CH3I) and 97–100% radiochemical purity (n = 7). Initial preclinical evaluation in rodent and nonhuman primate PET imaging studies revealed high initial brain uptake (peak rodent SUV = 2.5 @ 3 min postinjection; peak nonhuman primate SUV = 1.9 @ 5 min postinjection) followed by washout. Brain uptake was highest in thalamus, striatum, cortex, and cerebellum, areas known to be rich in GSK-3. These results make the arylindolemaleimide skeleton our lead scaffold for developing a PET radiotracer for quantification of GSK-3 density in vivo and ultimately translating it into clinical use. PMID:26005531
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Muzaffar, Saima; Shukla, Nilima; Srivastava, Amit; Angelini, Gianni D; Jeremy, Jamie Y
2005-01-01
Acute respiratory distress syndrome (ARDS) is associated with increased superoxide (O2•−) formation in the pulmonary vasculature and negation of the bioavailability of nitric oxide (NO). Since NO inhibits NADPH oxidase expression through a cyclic GMP-mediated mechanism, sildenafil, a type V phosphodiesterase inhibitor, may be therapeutically effective in ARDS through an augmentation of NO-mediated inhibition of NADPH oxidase. Therefore, the effect of sildenafil citrate and NO-donating sildenafil (NCX 911) on O2•− formation and gp91phox (active catalytic subunit of NADPH oxidase) expression was investigated in cultured porcine pulmonary artery endothelial cells (PAECs). PAECs were incubated with 10 nM TXA2 analogue, 9,11-dideoxy-9α,11α-methanoepoxy-prostaglandin F2α (U46619) (±sildenafil or NCX 911), for 16 h and O2•− formation measured spectrophometrically and gp91phox using Western blotting. The role of the NO-cGMP axis was studied using morpholinosydnonimine hydrochloride (SIN-1), the diethylamine/NO complex (DETA-NONOate), the guanylyl cyclase inhibitor, 1H-{1,2,4}oxadiazolo{4,3-a}quinoxalin-1-one (ODQ), and the protein kinase G inhibitor, 8-bromoguanosine-3′,5′-cyclic monophosphorothioate, Rp-isomer (Rp-8-Br-cGMPS). NO release was studied using a fluorescence assay and O2•−–NO interactions by measuring nitrites. After a 16-h incubation with 10 nM U46619, both NCX 911 and sildenafil elicited a concentration-dependent inhibition of O2•− formation and gp91phox expression, NCX 911 being more potent (IC50; 0.26 nM) than sildenafil citrate (IC50; 1.85 nM). These inhibitory effects were reversed by 1 μM ODQ and 10 μM Rp-8-Br-cGMPS. NCX 911 stimulated the formation of cGMP in PAECs and generated NO in a cell-free system to a greater degree than sildenafil citrate. The inhibitory effect of sildenafil was augmented by 1 μM SIN-1 and blocked partially by the eNOS inhibitor 10 μM N5-(1-iminoethyl)-ornithine (L
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Mechanistic Studies of Combustion and Structure Formation During Synthesis of Advanced Materials
NASA Technical Reports Server (NTRS)
Varma, A.; Lau, C.; Mukasyan, A. S.
2001-01-01
Combustion in a variety of heterogeneous systems, leading to the synthesis of advanced materials, is characterized by high temperatures (2000-3500 K) and heating rates (up to 10(exp 6) K/s) at and ahead of the reaction front. These high temperatures generate liquids and gases which are subject to gravity-driven flow. The removal of such gravitational effects is likely to provide increased control of the reaction front, with a consequent improvement in control of the microstructure of the synthesized products. Thus, microgravity (mu-g) experiments lead to major advances in the understanding of fundamental aspects of combustion and structure formation under the extreme conditions of the combustion synthesis (CS) wave. In addition, the specific features of microgravity environment allow one to produce unique materials, which cannot be obtained under terrestrial conditions. The current research is a logic continuation of our previous work on investigations of the fundamental phenomena of combustion and structure formation that occur at the high temperatures achieved in a CS wave. Our research is being conducted in three main directions: 1) Microstructural Transformations during Combustion Synthesis of Metal-Ceramic Composites. The studies are devoted to the investigation of particle growth during CS of intermetallic-ceramic composites, synthesized from nickel, aluminum, titanium, and boron metal reactants. To determine the mechanisms of particle growth, the investigation varies the relative amount of components in the initial mixture to yield combustion wave products with different ratios of solid and liquid phases, under 1g and mu-g conditions; 2) Mechanisms of Heat Transfer during Reactions in Heterogeneous Media. Specifically, new phenomena of gasless combustion wave propagation in heterogeneous media with porosity higher than that achievable in normal gravity conditions, are being studied. Two types of mixtures are investigated: clad powders, where contact between
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Paganelli, Fernanda L; van de Kamer, Tim; Brouwer, Ellen C; Leavis, Helen L; Woodford, Neil; Bonten, Marc J M; Willems, Rob J L; Hendrickx, Antoni P A
2017-03-01
Enterococcus faecium is a multidrug-resistant (MDR) nosocomial pathogen causing significant morbidity in debilitated patients. New antimicrobials are needed to treat antibiotic-resistant E. faecium infections in hospitalised patients. E. faecium incorporates lipoteichoic acid (LTA) (1,3-polyglycerol-phosphate linked to glycolipid) in its cell wall. The small-molecule inhibitor 1771 [2-oxo-2-(5-phenyl-1,3,4-oxadiazol-2-ylamino)ethyl 2-naphtho[2,1-b]furan-1-ylacetate] specifically blocks the activity of Staphylococcus aureus LtaS synthase, which polymerises 1,3-glycerolphosphate into LTA polymers. Here we characterised the effects of the small-molecule inhibitor 1771 on the growth of E. faecium isolates, alone (28 strains) or in combination with the antibiotics vancomycin, daptomycin, ampicillin, gentamicin or linezolid (15 strains), and on biofilm formation (16 strains). Inhibition of LTA synthesis at the surface of the cell by compound 1771 in combination with current antibiotic therapy abrogates enterococcal growth in vitro but does not affect mature E. faecium biofilms. Targeting LTA synthesis may provide new possibilities to treat MDR E. faecium infections. Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.
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Manjulatha, Khanapur; Srinivas, S; Mulakayala, Naveen; Rambabu, D; Prabhakar, M; Arunasree, Kalle M; Alvala, Mallika; Basaveswara Rao, M V; Pal, Manojit
2012-10-01
An improved synthesis of functionalized aurones has been accomplished via the reaction of benzofuran-3(2H)-one with a range of benzaldehydes in the presence of a mild base EDDA under ultrasound. A number of aurones were synthesized (within 5-30min) and the molecular structure of a representative compound determined by single crystal X-ray diffraction study confirmed Z-geometry of the C-C double bond present within the molecule. Some of the compounds synthesized have shown SIRT1 inhibiting as well as anti proliferative properties against two cancer cell lines in vitro. Compound 3a [(Z)-2-(5-bromo-2-hydroxybenzylidene) benzofuran-3(2H)-one] was identified as a potent inhibitor of SIRT1 (IC(50)=1μM) which showed a dose dependent increase in the acetylation of p53 resulting in induction of apoptosis. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Law, Jason M; Stark, Sebastian C; Liu, Ke; Liang, Norah E; Hussain, Mahmud M; Leiendecker, Matthias; Ito, Daisuke; Verho, Oscar; Stern, Andrew M; Johnston, Stephen E; Zhang, Yan-Ling; Dunn, Gavin P; Shamji, Alykhan F; Schreiber, Stuart L
2016-10-13
Evidence suggests that specific mutations of isocitrate dehydrogenases 1 and 2 (IDH1/2) are critical for the initiation and maintenance of certain tumor types and that inhibiting these mutant enzymes with small molecules may be therapeutically beneficial. In order to discover mutant allele-selective IDH1 inhibitors with chemical features distinct from existing probes, we screened a collection of small molecules derived from diversity-oriented synthesis. The assay identified compounds that inhibit the IDH1-R132H mutant allele commonly found in glioma. Here, we report the discovery of a potent (IC 50 = 50 nM) series of IDH1-R132H inhibitors having 8-membered ring sulfonamides as exemplified by the compound BRD2879. The inhibitors suppress ( R )-2-hydroxyglutarate production in cells without apparent toxicity. Although the solubility and pharmacokinetic properties of the specific inhibitor BRD2879 prevent its use in vivo , the scaffold presents a validated starting point for the synthesis of future IDH1-R132H inhibitors having improved pharmacological properties.
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Vanini, Giancarlo; Watson, Christopher J.; Lydic, Ralph; Baghdoyan, Helen A.
2009-01-01
Background Many general anesthetics are thought to produce a loss of wakefulness, in part, by enhancing gamma-aminobutyric acid (GABA) neurotransmission. However, GABAergic neurotransmission in the pontine reticular formation promotes wakefulness. This study tested the hypotheses that: 1) relative to wakefulness, isoflurane decreases GABA levels in the pontine reticular formation; and 2) pontine reticular formation administration of drugs that increase or decrease GABA levels increases or decreases, respectively, isoflurane induction time. Methods To test hypothesis 1, cats (n = 5) received a craniotomy and permanent electrodes for recording the electroencephalogram and electromyogram. Dialysis samples were collected from the pontine reticular formation during isoflurane anesthesia and wakefulness. GABA levels were quantified using high performance liquid chromatography. For hypothesis 2, rats (n = 10) were implanted with a guide cannula aimed for the pontine reticular formation. Each rat received microinjections of Ringer’s (vehicle control), the GABA uptake inhibitor nipecotic acid, and the GABA synthesis inhibitor 3-mercaptopropionic acid. Rats were then anesthetized with isoflurane and induction time was quantified as loss of righting reflex. Breathing rate was also measured. Results Relative to wakefulness, GABA levels were significantly decreased by isoflurane. Increased power in the electroencephalogram and decreased activity in the electromyogram caused by isoflurane co-varied with pontine reticular formation GABA levels. Nipecotic acid and 3-mercaptopropionic acid significantly increased and decreased, respectively, isoflurane induction time. Nipecotic acid also increased breathing rate. Conclusion Decreasing pontine reticular formation GABA levels comprises one mechanism by which isoflurane causes loss of consciousness, altered cortical excitability, muscular hypotonia, and decreased respiratory rate. PMID:19034094
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Rupiani, Sebastiano; Guidotti, Laura; Manerba, Marcella; Di Ianni, Lorenza; Giacomini, Elisa; Falchi, Federico; Di Stefano, Giuseppina; Roberti, Marinella; Recanatini, Maurizio
2016-11-22
Glycolysis is the main route for energy production in tumors. LDH-A is a key enzyme of this process and its inhibition represents an attractive strategy to hamper cancer cell metabolism. Galloflavin is a reliable LDH-A inhibitor as previously identified by us; however, its poor physicochemical properties and chemical tractability render it unsuitable for further development. Therefore, a rational design was undertaken with the aim to reproduce the pharmacophore of galloflavin on simpler, potentially more soluble and synthetic accessible scaffolds. Following a process of structural simplification, natural urolithin M6 (UM6), which is an ellagitannin metabolite produced by gut microbiota, was identified as a putative galloflavin mimetic. In the present study, the synthesis of UM6 is described for the first time. An efficient synthetic pathway has been developed, which involved five steps from readily accessible starting materials. The key reaction steps, a Suzuki coupling and an intramolecular C-H oxygenation, have been optimized to improve the synthetic feasibility and provide the best conditions in terms of reaction time and yield. Moreover, this route would be suitable to obtain other analogs for SAR studies. Preliminary biological tests revealed that UM6 was able to smoothly reproduce the behavior of galloflavin, confirming that our approach was successful in providing a new and accessible structure in the search for new LDH-A inhibitors.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Gilmour, Peter S., E-mail: Peter.Gilmour@astrazeneca.com; O'Shea, Patrick J.; Fagura, Malbinder
Wnt activation by inhibiting glycogen synthase kinase 3 (GSK-3) causes bone anabolism in rodents making GSK-3 a potential therapeutic target for osteoporotic and osteolytic metastatic bone disease. To understand the wnt pathway related to human disease translation, the ability of 3 potent inhibitors of GSK-3 (AZD2858, AR79, AZ13282107) to 1) drive osteoblast differentiation and mineralisation using human adipose-derived stem cells (hADSC) in vitro; and 2) stimulate rat bone formation in vivo was investigated. Bone anabolism/resorption was determined using clinically relevant serum biomarkers as indicators of bone turnover and bone formation assessed in femurs by histopathology and pQCT/μCT imaging. GSK-3 inhibitorsmore » caused β-catenin stabilisation in human and rat mesenchymal stem cells, stimulated hADSC commitment towards osteoblasts and osteogenic mineralisation in vitro. AZD2858 produced time-dependent changes in serum bone turnover biomarkers and increased bone mass over 28 days exposure in rats. After 7 days, AZD2858, AR79 or AZ13282107 exposure increased the bone formation biomarker P1NP, and reduced the resorption biomarker TRAcP-5b, indicating increased bone anabolism and reduced resorption in rats. This biomarker profile was differentiated from anabolic agent PTH{sub 1–34} or the anti-resorptive Alendronate-induced changes. Increased bone formation in cortical and cancellous bone as assessed by femur histopathology supported biomarker changes. 14 day AR79 treatment increased bone mineral density and trabecular thickness, and decreased trabecular number and connectivity assessed by pQCT/μCT. GSK-3 inhibition caused hADSC osteoblastogenesis and mineralisation in vitro. Increased femur bone mass associated with changes in bone turnover biomarkers confirmed in vivo bone formation and indicated uncoupling of bone formation and resorption. - Highlights: • Wnt modulation with 3 novel GSK-3 inhibitors alters bone growth. • Human stem cell
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Torres, Pablo S; Malamud, Florencia; Rigano, Luciano A; Russo, Daniela M; Marano, María Rosa; Castagnaro, Atilio P; Zorreguieta, Angeles; Bouarab, Kamal; Dow, John Maxwell; Vojnov, Adrián A
2007-01-01
Virulence of the black rot pathogen Xanthomonas campestris pv. campestris (Xcc) is regulated by cell–cell signalling involving the diffusible signal factor DSF. Synthesis and perception of DSF require products of genes within the rpf cluster (for regulation of pathogenicity factors). RpfF directs DSF synthesis whereas RpfC and RpfG are involved in DSF perception. Here we have examined the role of the rpf/DSF system in biofilm formation in minimal medium using confocal laser-scanning microscopy of GFP-labelled bacteria. Wild-type Xcc formed microcolonies that developed into a structured biofilm. In contrast, an rpfF mutant (DSF-minus) and an rpfC mutant (DSF overproducer) formed only unstructured arrangements of bacteria. A gumB mutant, defective in xanthan biosynthesis, was also unable to develop the typical wild-type biofilm. Mixed cultures of gumB and rpfF mutants formed a typical biofilm in vitro. In contrast, in mixed cultures the rpfC mutant prevented the formation of the structured biofilm by the wild-type and did not restore wild-type biofilm phenotypes to gumB or rpfF mutants. These effects on structured biofilm formation were correlated with growth and disease development by Xcc strains in Nicotiana benthamiana leaves. These findings suggest that DSF signalling is finely balanced during both biofilm formation and virulence. PMID:17635553
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Kwon, Soon Gu; Hyeon, Taeghwan
2008-12-01
Nanocrystals exhibit interesting electrical, optical, magnetic, and chemical properties not achieved by their bulk counterparts. Consequently, to fully exploit the potential of nanocrystals, the synthesis of nanocrystals must focus on producing materials with uniform size and shape. Top-down physical processes can produce large quantities of nanocrystals, but controlling the size is difficult with these methods. On the other hand, colloidal chemical synthetic methods can produce uniform nanocrystals with a controlled particle size. In this Account, we present our synthesis of uniform nanocrystals of various shapes and materials, and we discuss the kinetics of nanocrystal formation. We employed four different synthetic approaches including thermal decomposition, nonhydrolytic sol-gel reactions, thermal reduction, and use of reactive chalcogen reagents. We synthesized uniform oxide nanocrystals via heat-up methods. This method involved slowly heat-up reaction mixtures composed of metal precursors, surfactants, and solvents from room temperature to high temperature. We then held reaction mixtures at an aging temperature for a few minutes to a few hours. Kinetics studies revealed a three-step mechanism for the synthesis of nanocrystals through the heat-up method with size distribution control. First, as metal precursors thermally decompose, monomers accumulate. At the aging temperature, burst nucleation occurs rapidly; at the end of this second phase, nucleation stops, but continued diffusion-controlled growth leads to size focusing to produce uniform nanocrystals. We used nonhydrolytic sol-gel reactions to synthesize various transition metal oxide nanocrystals. We employed ester elimination reactions for the synthesis of ZnO and TiO(2) nanocrystals. Uniform Pd nanoparticles were synthesized via a thermal reduction reaction induced by heating up a mixture of Pd(acac)(2), tri-n-octylphosphine, and oleylamine to the aging temperature. Similarly, we synthesized
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Cell proliferation and progesterone synthesis depend on lipid metabolism in bovine granulosa cells.
Elis, Sebastien; Desmarchais, Alice; Maillard, Virginie; Uzbekova, Svetlana; Monget, Philippe; Dupont, Joëlle
2015-03-15
In dairy cows, lipids are essential to support energy supplies for all biological functions, especially during early lactation. Lipid metabolism is crucial for sustaining proper reproductive function. Alteration of lipid metabolism impacts follicular development and affects oocyte developmental competence. Indeed, nonesterified fatty acids are able to decrease granulosa cell (GC) proliferation and affect estradiol synthesis, thus potentially affecting follicular growth and viability. The objective of this study was to assess the impact of lipid metabolism on bovine GCs, through the use of the lipid metabolism inhibitors etomoxir, an inhibitor of fatty acid (FA) oxidation through inhibition of carnitine palmitoyl transferase 1 (CPT1), and C75, an inhibitor of FA synthesis through inhibition of fatty acid synthase. We showed that etomoxir and C75 significantly inhibited DNA synthesis in vitro; C75 also significantly decreased progesterone synthesis. Both inhibitors significantly reduced AMPK (5' adenosine monophosphate-activated protein kinase) and acetyl-CoA carboxylase phosphorylation. Etomoxir also affected the AKT (protein kinase B) signaling pathway. Combined, these data suggest that both FA oxidation and synthesis are important for the bovine GCs to express a proliferative and steroidogenic phenotype and, thus, for sustaining follicular growth. Despite these findings, it is important to note that the changes caused by the inhibitors of FA metabolism on GCs in vitro are globally mild, suggesting that lipid metabolism is not as critical in GCs as was observed in the oocyte-cumulus complex. Further studies are needed to investigate the detailed mechanisms by which lipid metabolism interacts with GC functions. Copyright © 2015 Elsevier Inc. All rights reserved.
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HDAC inhibitors: a 2013-2017 patent survey.
Faria Freitas, Micaela; Cuendet, Muriel; Bertrand, Philippe
2018-04-19
Zinc-dependent histone deacetylases (HDAC) inhibitors represent an important class of biologically active compounds with four of them approved by the FDA. A wide range of molecules has been reported for applications in several human diseases.Area covered: This review covers recent efforts in the synthesis and applications of HDAC inhibitors from 2013-2017.Expert opinion: HDAC inhibitors represent an important class of biologically active compounds for single or combination therapies. The current synthetic methodologies are oriented towards selective HDAC isoforms to achieve better therapeutic effects. Among the recent patents available, most of them focus on HDAC6 selective inhibitors. Beside this search for isoform selectivity, the quest for zinc binding groups with better pharmacokinetic properties and high potency against HDACs only motivates medicinal chemists, as well as the design of inhibitors targeting HDACs and at the same time another biological target. If the major applications are for anticancer activity, one can note the emerging applications in neurological or metabolic disorders or for the stimulation of the immune system.
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Parish, E J; Honda, H; Chitrakorn, S; Taylor, F R
1988-10-01
A facile chemical synthesis of lanost-8-en-3 beta-ol-24-one (24-ketolanosterol) is described. This compound was found to be a potent inhibitor of 3-hydroxy-3-methylglutaryl (HMG) CoA reductase activity in cultured mouse L cells. The synthetic scheme developed in this study utilizes commercial lanosterol as a starting material and involves selective hydroboration of the C-24 double bond followed by oxidation of the carbon-boron bond at C-24 by pyridinium chlorochromate (PCC).
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Inhibition of fatty acid synthesis in isolated adipocytes by 5-(tetradecyloxy)-2-furoic acid.
Halvorson, D L; McCune, S A
1984-11-01
The compound 5-(tetradecyloxy)-2-furoic acid (TOFA), a hypolipidemic agent, inhibits fatty acid synthesis, lactate and pyruvate accumulation and CO2 release in isolated rat adipocytes. TOFA stimulates the accumulation of citrate. ATP levels are not lowered by TOFA. In comparison with the natural fatty acid, oleate, TOFA exhibited a much greater inhibitory effect on lipogenesis. TOFyl-CoA formation within intact adipocytes was demonstrated. Although not inhibited by TOFA, acetyl-CoA carboxylase is inhibited by TOFyl-CoA. It is proposed that many of the metabolic effects of TOFA in isolated adipocytes can be explained by TOFyl-CoA inhibition of acetyl-CoA carboxylase. TOFA inhibits glycolysis as a secondary event with the primary event of inhibition of fatty acid synthesis causing an accumulation of citrate which is an inhibitor of phosphofructokinase.
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Cardozo, Suzana Vanessa S.; Carvalho, Vinicius de Frias; Romeiro, Nelilma Correia; Silva, Patrícia Machado Rodrigues e; Martins, Marco Aurélio; Barreiro, Eliezer J.; Lima, Lídia Moreira
2016-01-01
Prior investigations showed that increased levels of cyclic AMP down-regulate lung inflammatory changes, stimulating the interest in phosphodiesterase (PDE)4 as therapeutic target. Here, we described the synthesis, pharmacological profile and docking properties of a novel sulfonamide series (5 and 6a-k) designed as PDE4 inhibitors. Compounds were screened for their selectivity against the four isoforms of human PDE4 using an IMAP fluorescence polarized protocol. The effect on allergen- or LPS-induced lung inflammation and airway hyper-reactivity (AHR) was studied in A/J mice, while the xylazine/ketamine-induced anesthesia test was employed as a behavioral correlate of emesis in rodents. As compared to rolipram, the most promising screened compound, 6a (LASSBio-448) presented a better inhibitory index concerning PDE4D/PDE4A or PDE4D/PDE4B. Accordingly, docking analyses of the putative interactions of LASSBio-448 revealed similar poses in the active site of PDE4A and PDE4C, but slight unlike orientations in PDE4B and PDE4D. LASSBio-448 (100 mg/kg, oral), 1 h before provocation, inhibited allergen-induced eosinophil accumulation in BAL fluid and lung tissue samples. Under an interventional approach, LASSBio-448 reversed ongoing lung eosinophilic infiltration, mucus exacerbation, peribronchiolar fibrosis and AHR by allergen provocation, in a mechanism clearly associated with blockade of pro-inflammatory mediators such as IL-4, IL-5, IL-13 and eotaxin-2. LASSBio-448 (2.5 and 10 mg/kg) also prevented inflammation and AHR induced by LPS. Finally, the sulfonamide derivative was shown to be less pro-emetic than rolipram and cilomilast in the assay employed. These findings suggest that LASSBio-448 is a new PDE4 inhibitor with marked potential to prevent and reverse pivotal pathological features of diseases characterized by lung inflammation, such as asthma. PMID:27695125
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Tsimafeyeu, Ilya; Daeyaert, Frits; Joos, Jean-Baptiste; Aken, Koen V; Ludes-Meyers, John; Byakhov, Mikhail; Tjulandin, Sergei
2016-01-01
Fibroblast growth factor (FGF) receptors (FGFRs) play a key role in tumor growth and angiogenesis. The present report describes our search for an extracellularly binding FGFR inhibitor using a combined molecular modeling and de novo design strategy. Based upon crystal structures of the receptor with its native ligand and knowledge of inhibiting peptides, we have developed a computational protocol that predicts the putative binding of a molecule to the extracellular domains of the receptor. This protocol, or scoring function, was used in combination with the de novo synthesis program 'SYNOPSIS' to generate high scoring and synthetically accessible compounds. Eight compounds belonging to 3 separate chemical classes were synthesized. One of these compounds, alofanib (RPT835), was found to be an effective inhibitor of the FGF/FGFR2 pathway. The preclinical in vitro data support an allosteric inhibition mechanism of RPT835. RPT835 potently inhibited growth of KATO III gastric cancer cells expressing FGFR2, with GI50 value of 10 nmol/L. These results provide strong rationale for the evaluation of compound in advanced cancers.
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Ghosh, Arun K; R Nyalapatla, Prasanth; Kovela, Satish; Rao, Kalapala Venkateswara; Brindisi, Margherita; Osswald, Heather L; Amano, Masayuki; Aoki, Manabu; Agniswamy, Johnson; Wang, Yuan-Fang; Weber, Irene T; Mitsuya, Hiroaki
2018-05-24
The design, synthesis, and biological evaluation of a new class of HIV-1 protease inhibitors containing stereochemically defined fused tricyclic polyethers as the P2 ligands and a variety of sulfonamide derivatives as the P2' ligands are described. A number of ring sizes and various substituent effects were investigated to enhance the ligand-backbone interactions in the protease active site. Inhibitors 5c and 5d containing this unprecedented fused 6-5-5 ring system as the P2 ligand, an aminobenzothiazole as the P2' ligand, and a difluorophenylmethyl as the P1 ligand exhibited exceptional enzyme inhibitory potency and maintained excellent antiviral activity against a panel of highly multidrug-resistant HIV-1 variants. The umbrella-like P2 ligand for these inhibitors has been synthesized efficiently in an optically active form using a Pauson-Khand cyclization reaction as the key step. The racemic alcohols were resolved efficiently using a lipase catalyzed enzymatic resolution. Two high resolution X-ray structures of inhibitor-bound HIV-1 protease revealed extensive interactions with the backbone atoms of HIV-1 protease and provided molecular insight into the binding properties of these new inhibitors.
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Lawson, Marie; Rodrigo, Jordi; Baratte, Blandine; Robert, Thomas; Delehouzé, Claire; Lozach, Olivier; Ruchaud, Sandrine; Bach, Stéphane; Brion, Jean-Daniel; Alami, Mouad; Hamze, Abdallah
2016-11-10
We report here the synthesis, the biological evaluation and the molecular modeling studies of new imidazo[1,2-a]pyridines derivatives designed as potent kinase inhibitors. This collection was obtained from 2-aminopyridines and 2-bromoacetophenone which afforded final compound in only one step. The bioactivity of this family of new compounds was tested using protein kinase and ATP competition assays. The structure-activity relationship (SAR) revealed that six compounds inhibit DYRK1A and CLK1 at a micromolar range. Docking studies provided possible explanations that correlate with the SAR data. The most active compound 4c inhibits CLK1 (IC50 of 0.7 μM) and DYRK1A (IC50 of 2.6 μM). Copyright © 2016 Elsevier Masson SAS. All rights reserved.
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Gene therapy for haemophilia: prospects and challenges to prevent or reverse inhibitor formation.
Scott, David W; Lozier, Jay N
2012-02-01
Monogenic hereditary diseases, such as haemophilia A and B, are ideal targets for gene therapeutic approaches. While these diseases can be treated with protein therapeutics, such as factor VIII (FVIII) or IX (FIX), the notion that permanent transfer of the genes encoding these factors can cure haemophilia is very attractive. An underlying problem with a gene therapy approach, however, is the patient's immune response to the therapeutic protein (as well as to the transmission vector), leading to the formation of inhibitory antibodies. Even more daunting is reversing an existing immune response in patients with pre-existing inhibitors. In this review, we will describe the laboratory and clinical progress, and the challenges met thus far, in achieving the goal of gene therapy efficacy, with a focus on the goal of tolerance induction. Published 2011. This article is a US Government work and is in the public domain in the USA.
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Cathcart, George R; Gilmore, Brendan F; Greer, Brett; Harriott, Pat; Walker, Brian
2009-11-01
We report on the synthesis and biological evaluation of a focussed library of N-alpha mercaptoamide containing dipeptides as inhibitors of the zinc metallopeptidase Pseudomonas aeruginosa elastase (LasB, EC 3.4.24.26). The aim of the study was to derive an inhibitor profile for LasB with regard to mapping the S'1 binding site of the enzyme. Consequently, a focussed library of 160 members has been synthesised, using standard Fmoc-solid phase methods (on a Rink-amide resin), in which a subset of amino acids including examples of those with basic (Lys, Arg), aromatic (Phe, Trp), large aliphatic (Val, Leu) and acidic (Asp, Glu) side-chains populated the P'2 position of the inhibitor sequence and all 20 natural amino acids were incorporated, in turn, at the P'1 position. The study has revealed a preference for aromatic and/or large aliphatic amino acids at P'1 and a distinct bias against acidic residues at P'2. Ten inhibitor sequences were discovered that exhibited sub to low micromolar Ki values.
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Ohta, Kazumasa; Takahashi, Chifumi; Tosuji, Hiroaki
2009-08-01
The activity of acetylcholinesterase (AchE) increases rapidly after the gastrula stage of sea urchin development. In this report, changes in activity and in the molecular differentiation of AchE were investigated. AchE activity increased slightly during gastrulation and rose sharply thereafter, and was dependent on new RNA synthesis. No activity of butyrylcholinesterase was found. Morphogenesis in sea urchin embryos was inhibited by the AchE inhibitor eserine, which specifically inhibited arm rod formation but not body rod formation. Spicule formation and enzyme activity in cultured micromeres were inhibited by eserine in a dose-dependent manner. During gastrulation, two molecular forms of AchE were detected with polyacrylamide gel electrophoresis. The appearance of an additional band on the gel was consistent with the occurrence of a remarkable increase in the enzyme activity. This additional band appeared as a larger molecular form in Anthocidaris crassispina, Hemicentrotus pulcherrimus, Stomopneustes variolaris, and Strongylocentrotus nudus, and as a smaller form in Clypeaster japonicus and Temnopleurus hardwicki. These results suggest that the change in the molecular form of AchE induced a change in enzymatic activity that in turn may play a role in spicule elongation in sea urchin embryos.
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Samadi, Abdelouahid; de los Ríos, Cristóbal; Bolea, Irene; Chioua, Mourad; Iriepa, Isabel; Moraleda, Ignacio; Bartolini, Manuela; Andrisano, Vincenza; Gálvez, Enrique; Valderas, Carolina; Unzeta, Mercedes; Marco-Contelles, José
2012-06-01
The synthesis, pharmacological evaluation and molecular modeling of heterocyclic substituted alkyl and cycloalkyl propargyl amines 1-7 of type I, and 9-12 of type II, designed as multipotent inhibitors able to simultaneously inhibit monoamine oxidases (MAO-A/B) as well as cholinesterase (AChE/BuChE) enzymes, as potential drugs for the treatment of Alzheimer's disease, are described. Indole derivatives 1-7 of type I are well known MAO inhibitors whose capacity to inhibit AChE and BuChE was here investigated for the first time. As a result, compound 7 was identified as a MAO-B inhibitor (IC(50) = 31 ± 2 nM) and a moderately selective eqBuChE inhibitor (IC(50) = 4.7 ± 0.2 μM). Conversely, the new and readily available 5-amino-7-(prop-2-yn-1-yl)-6,7,8,9-tetrahydropyrido[2,3-b][1,6]naphthyridine derivatives 9-13 of type II are poor MAO inhibitors, but showed AChE selective inhibition, compound 12 being the most attractive as it acts as a non-competitive inhibitor on EeAChE (IC(50) = 25 ± 3 nM, K(i) = 65 nM). The ability of this compound to interact with the AChE peripheral binding site was confirmed by kinetic studies and by molecular modeling investigation. Studies on human ChEs confirmed that 12 is a selective AChE inhibitor with inhibitory potency in the submicromolar range. Moreover, in agreement with its mode of action, 12 was shown to be able to inhibit Aβ aggregation induced by hAChE by 30.6%. Copyright © 2012 Elsevier Masson SAS. All rights reserved.
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Latli, Bachir; Hrapchak, Matt; Chevliakov, Maxim; Li, Guisheng; Campbell, Scot; Busacca, Carl A; Senanayake, Chris H
2015-05-30
Deleobuvir, (2E)-3-(2-{1-[2-(5-bromopyrimidin-2-yl)-3-cyclopentyl-1-methyl-1H-indole-6-carboxamido]cyclobutyl}-1-methyl-1H-benzimidazol-6-yl)prop-2-enoic acid (1), is a non-nucleoside, potent, and selective inhibitor of hepatitis C virus NS5B polymerase. Herein, we describe the detailed synthesis of this compound labeled with carbon-13 and carbon-14. The synthesis of its three major metabolites, namely, the reduced double bond metabolite (2) and the acyl glucuronide derivatives of (1) and (2), is also reported. Aniline-(13) C6 was the starting material to prepare butyl (E)-3-(3-methylamino-4-nitrophenyl-(13) C6 )acrylate [(13) C6 ]-(11) in six steps. This intermediate was then used to obtain [(13) C6 ]-(1) and [(13) C6 ]-(2) in five and four more steps, respectively. For the radioactive synthesis, potassium cyanide-(14) C was used to prepare 1-cylobutylaminoacid [(14) C]-(23) via Buchrer-Bergs reaction. The carbonyl chloride of this acid was then used to access both [(14) C]-(1) and [(14) C]-(2) in four steps. The acyl glucuronide derivatives [(13) C6 ]-(3), [(13) C6 ]-(4) and [(14) C]-(3) were synthesized in three steps from the acids [(13) C6 ]-(1), [(13) C6 ]-(2) and [(14) C]-(1) using known procedures. Copyright © 2015 John Wiley & Sons, Ltd.
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Dgachi, Youssef; Ismaili, Lhassane; Knez, Damijan; Benchekroun, Mohamed; Martin, Hélène; Szałaj, Natalia; Wehle, Sarah; Bautista-Aguilera, Oscar M; Luzet, Vincent; Bonnet, Alexandre; Malawska, Barbara; Gobec, Stanislav; Chioua, Mourad; Decker, Michael; Chabchoub, Fakher; Marco-Contelles, José
2016-06-20
Given the complex nature of Alzheimer's disease (AD), compounds that are able to simultaneously address two or more AD-associated targets show greater promise for development into drugs for AD therapy. Herein we report an efficient two-step synthesis and biological evaluation of new racemic benzochromene derivatives as antioxidants, inhibitors of cholinesterase and β-amyloid (Aβ1-42 ) aggregation. Based on the results of the primary screening, we identified 15-(3-methoxyphenyl)-9,11,12,15-tetrahydro-10H,14H-benzo[5,6]chromeno[2,3-d]pyrido[1,2-a]pyrimidin-14-imine (3 e) and 16-(3-methoxyphenyl)-9,10,11,12,13,16-hexahydro-15H-benzo[5',6']chromeno[2',3':4,5]pyrimido[1,2-a]azepin-15-imine (3 f) as new potential multitarget-directed ligands for AD therapy. Further in-depth biological analysis showed that compound 3 f is a good human acetylcholinesterase inhibitor [IC50 =(0.36±0.02) μm], has strong antioxidant activity (3.61 μmol Trolox equivalents), and moderate Aβ1-42 antiaggregating power (40.3 %). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Qian, Keduo; Kuo, Reen-Yun; Chen, Chin-Ho; Huang, Li; Morris-Natschke, Susan L; Lee, Kuo-Hsiung
2010-04-22
In our continuing study of triterpene derivatives as potent anti-HIV agents, different C-3 conformationally restricted betulinic acid (BA, 1) derivatives were designed and synthesized in order to explore the conformational space of the C-3 pharmacophore. 3-O-Monomethylsuccinyl-betulinic acid (MSB) analogues were also designed to better understand the contribution of the C-3' dimethyl group of bevirimat (2), the first-in-class HIV maturation inhibitor, which is currently in phase IIb clinical trials. In addition, another triterpene skeleton, moronic acid (MA, 3), was also employed to study the influence of the backbone and the C-3 modification toward the anti-HIV activity of this compound class. This study enabled us to better understand the structure-activity relationships (SAR) of triterpene-derived anti-HIV agents and led to the design and synthesis of compound 12 (EC(50): 0.0006 microM), which displayed slightly better activity than 2 as a HIV-1 maturation inhibitor.
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Monte, Fabio Lo; Kramer, Thomas; Boländer, Alexander; Plotkin, Batya; Eldar-Finkelman, Hagit; Fuertes, Ana; Dominguez, Juan; Schmidt, Boris
2011-09-15
The glycogen synthase kinase 3 (GSK-3) is implicated in multiple cellular processes and has been linked to the pathogenesis of Alzheimer's disease (AD). In the course of our research topic we synthesized a library of potent GSK-3 inhibitors. We utilized the urea scaffold present in the potent and highly selective GSK-3 inhibitor AR-A014418 (AstraZeneca). This moiety suits both (a) a convergent approach utilizing readily accessible building blocks and (b) a divergent approach based on a microwave heating assisted Suzuki coupling. We established a chromatography-free purification method to generate products with sufficient purity for the biological assays. The structure-activity relationship of the library provided the rationale for the synthesis of the benzothiazolylurea 66 (IC(50)=140 nM) and the pyridylurea 62 (IC(50)=98 nM), which displayed two to threefold enhanced activity versus the reference compound 18 (AR-A014418: IC(50)=330 nM) in our assays. Copyright © 2011. Published by Elsevier Ltd.
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Chung, Thomas D Y; Sergienko, Eduard; Millán, José Luis
2010-04-27
The tissue-nonspecific alkaline phosphatase (TNAP) isozyme is centrally involved in the control of normal skeletal mineralization and pathophysiological abnormalities that lead to disease states such as hypophosphatasia, osteoarthritis, ankylosis and vascular calcification. TNAP acts in concert with the nucleoside triphosphate pyrophosphohydrolase-1 (NPP1) and the Ankylosis protein to regulate the extracellular concentrations of inorganic pyrophosphate (PP(i)), a potent inhibitor of mineralization. In this review we describe the serial development of two miniaturized high-throughput screens (HTS) for TNAP inhibitors that differ in both signal generation and detection formats, but more critically in the concentrations of a terminal alcohol acceptor used. These assay improvements allowed the rescue of the initially unsuccessful screening campaign against a large small molecule chemical library, but moreover enabled the discovery of several unique classes of molecules with distinct mechanisms of action and selectivity against the related placental (PLAP) and intestinal (IAP) alkaline phosphatase isozymes. This illustrates the underappreciated impact of the underlying fundamental assay configuration on screening success, beyond mere signal generation and detection formats.
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ATP Synthesis in the Extremely Halophilic Bacteria
NASA Technical Reports Server (NTRS)
Hochstein, Lawrence I.; Morrison, David (Technical Monitor)
1994-01-01
The proton-translocating ATPases are multimeric enzymes that carry out a multitude of essential functions. Their origin and evolution represent a seminal event in the early evolution of life. Amino acid sequences of the two largest subunits from archaeal ATPases (A-ATPases), vacuolar ATPases (V-ATPases), and FOF1-ATP syntheses (FATPases) suggest these ATPases evolved from an ancestral vacuolar-like ATP syntheses. A necessary consequence of this notion is that the A-ATPases are ATP syntheses. With the possible exception of the A-ATPase from Halobacterium salinarium. no A-ATPase has been demonstrated to synthesize ATP. The evidence for this case is dubious since ATP synthesis occurs only when conditions are distinctively unphysiological. We demonstrated that ATP synthesis in H.saccharovorum is inconsistent with the operation of an A-type ATPase. In order to determine if this phenomenon was unique to H. saccharovorum, ATP synthesis was examined in various extremely halophilic bacteria with the goal of ascertaining if it resembled what occurred in a. saccharovorum, or was consistent with the operation of an A-type ATPase. A-, V-, and F-type ATPases respond singularly to certain inhibitors. Therefore, the effect of these inhibitors on ATP synthesis in several extreme halophiles was determined. Inhibitors that either blocked or collapsed proton-gradients inhibited the steady state synthesis of ATP thus verifying that synthesis took place at the expense of a proton gradient. Azide, an inhibitor of F-ATPases inhibited ATP synthesis. Since the arginine-dependent synthesis of ATP, which occurs by way of substrate-level phosphorylation, was unaffected by azide, it was unlikely that azide acted as an "uncoupler." N -ethylmaleimide and nitrate, which inhibit V- and A-ATPases, either did not inhibit ATP synthesis or resulted in higher steady-state levels of ATP. These results suggest there are two types of proton-motive ATPases in the extreme halophiles (and presumably in other
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Characterization of Encapsulated Corrosion Inhibitors for Environmentally Friendly Smart Coatings
NASA Technical Reports Server (NTRS)
Pearman, Benjamin Pieter; Li, Wenyan; Buhrow, Jerry; Zhang, Xuejun; Surma, Jan; Fitzpatrick, Lilly; Montgomery, Eliza; Calle, Luz Marina
2014-01-01
Research efforts are under way to replace current corrosion inhibitors with more environmentally friendly alternatives. However, problems with corrosion inhibition efficiency, coating compatibility and solubility have hindered the use of many of these materials as simple pigment additives.This paper will present technical details on how the Corrosion Technology Lab at NASAs Kennedy Space Center (KSC) has addressed these issues by encapsulating environmentally friendly inhibitors into organic and inorganic microparticles and microcapsules. The synthetic process for polymer particles was characterized and post-synthesis analysis was performed to determine the interactions between the inhibitors and the encapsulation material. The pH-controlled release of inhibitors from various particle formulations in aqueous base was monitored and compared to both electrochemical and salt immersion accelerated corrosion experiment. Furthermore, synergistic corrosion inhibition effects observed during the corrosion testing of several inhibitor combinations will be presented.
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Channar, Pervaiz Ali; Saeed, Aamer; Larik, Fayaz Ali; Rafiq, Muhammad; Ashraf, Zaman; Jabeen, Farukh; Fattah, Tanzeela Abdul
2017-11-01
The present article describes the synthesis and enzyme inhibitory kinetics of methyl[2-(arylmethylene-hydrazono)-4-oxo-thiazolidin-5-ylidene]acetates 5a-j as mushroom tyrosinase inhibitors. The title compounds were synthesized via cyclocondensation of thiosemicarbazones 3a-j with dimethyl but-2-ynedioate (DMAD) 4 in good yields under solvent-free conditions. The synthesized compounds were evaluated for their potential to inhibit the activity of mushroom tyrosinase. It was unveiled that compounds 5i showed excellent enzyme inhibitory activity with IC 50 3.17µM while IC 50 of standard kojic acid is 15.91µM. The presence of heterocyclic pyridine ring in compound 5i play important role in enzyme inhibitory activity as rest of the functional groups are common in all synthesized compounds. The enzyme inhibitory kinetics of the most potent derivative 5i determined by Lineweaver-Burk plots and Dixon plots showed that it is non-competitive inhibitor with Ki value 1.5µM. It was further investigated that the wet lab results are in good agreement with the computational results. The molecular docking of the synthesized compounds was performed against tyrosinase protein (PDBID 2Y9X) to delineate ligand-protein interactions at molecular level. The docking results showed that the major interacting residues are His244, His85, His263, Val 283, His 296, Asn260, Val248, His260, His261 and Phe264 which are located in active binding site of the protein. The molecular modeling demonstrates that the oxygen atom of the compound 5i coordinated with the key residues in the active site of mushroom tyrosinase contribute significantly against inhibitory ability and diminishing the human melanin synthesis. These results evident that compound 5i is a lead structure in developing most potent mushroom tyrosinase inhibitors. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Jafari, Behzad; Ospanov, Meirambek; Ejaz, Syeda Abida; Yelibayeva, Nazym; Khan, Shafi Ullah; Amjad, Sayyeda Tayyeba; Safarov, Sayfidin; Abilov, Zharylkasyn A; Turmukhanova, Mirgul Zh; Kalugin, Sergey N; Ehlers, Peter; Lecka, Joanna; Sévigny, Jean; Iqbal, Jamshed; Langer, Peter
2018-01-20
Alkaline Phosphatases (APs) play a key role in maintaining a ratio of phosphate to inorganic pyrophosphate (P i /PP i ) and thus regulate extracellular matrix calcification during bone formation and growth. Among different isozymes of AP, aberrant increase in the level of tissue non-specific alkaline phosphatase (TNAP) is strongly associated with vascular calcification and end-stage renal diseases. In this context, we synthesized a novel series of fluorinated pyrimidone derivatives, i.e., 2-bromo-7-trifluoromethyl-5-oxo-5H-1,3,4-thiadiazolepyrimidones. The bromine functionality was further used for derivatisation by nucleophilic aromatic substitution using amines as nucleophiles as well as by Palladium catalysed Suzuki-Miyaura reactions. The synthesized derivatives were found potent but non-selective inhibitors of both isozymes of AP. Arylated thiadiazolopyrimidones exhibited stronger inhibitory activities than 2-amino-thiadiazolopyrimidones. The binding modes and possible interactions of the most active inhibitor within the active site of the enzyme were observed by molecular docking studies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
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Cao, Yu; Chen, Min; Tang, Dehua; Yan, Hongli; Ding, Xiwei; Zhou, Fan; Zhang, Mingming; Xu, Guifang; Zhang, Weijie; Zhang, Shu; Zhuge, Yuzheng; Wang, Lei; Zou, Xiaoping
2018-05-22
Proton pump inhibitors (PPIs) play a role in antitumor activity, with studies showing specialized impacts of PPIs on cancer cell apoptosis, metastasis, and autophagy. In this study, we demonstrated that pantoprazole (PPI) increased autophagosomes formation and affected autophagic flux depending on the pH conditions. PPI specifically elevated SQSTM1 protein levels by increasing SQSTM1 transcription via NFE2L2 activation independent of the specific effect of PPI on autophagic flux. Via decreasing proteasome subunits expression, PPI significantly impaired the function of the proteasome, accompanied by the accumulation of undegraded poly-ubiquitinated proteins. Notably, PPI-induced autophagy functioned as a downstream response of proteasome inhibition by PPI, while suppressing protein synthesis abrogated autophagy. Blocking autophagic flux in neutral pH condition or further impairing proteasome function with proteasome inhibitors, significantly aggravated PPI cytotoxicity by worsening protein degradation ability. Interestingly, under conditions of mitochondrial stress, PPI showed significant synergism when combined with Bcl-2 inhibitors. Taken together, these findings provide a new understanding of the impact of PPIs on cancer cells' biological processes and highlight the potential to develop more efficient and effective combination therapies.
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Xie, Xiaolei; Le, Li; Fan, Yanxin; Lv, Lin; Zhang, Junjie
2012-07-01
Mitoribosome in mammalian cells is responsible for synthesis of 13 mtDNA-encoded proteins, which are integral parts of four mitochondrial respiratory chain complexes (I, III, IV and V). ERAL1 is a nuclear-encoded GTPase important for the formation of the 28S small mitoribosomal subunit. Here, we demonstrate that knockdown of ERAL1 by RNA interference inhibits mitochondrial protein synthesis and promotes reactive oxygen species (ROS) generation, leading to autophagic vacuolization in HeLa cells. Cells that lack ERAL1 expression showed a significant conversion of LC3-I to LC3-II and an enhanced accumulation of autophagic vacuoles carrying the LC3 marker, all of which were blocked by the autophagy inhibitor 3-MA as well as by the ROS scavenger NAC. Inhibition of mitochondrial protein synthesis either by ERAL1 siRNA or chloramphenicol (CAP), a specific inhibitor of mitoribosomes, induced autophagy in HTC-116 TP53 (+/+) cells, but not in HTC-116 TP53 (-/-) cells, indicating that tumor protein 53 (TP53) is essential for the autophagy induction. The ROS elevation resulting from mitochondrial protein synthesis inhibition induced TP53 expression at transcriptional levels by enhancing TP53 promoter activity, and increased TP53 protein stability by suppressing TP53 ubiquitination through MAPK14/p38 MAPK-mediated TP53 phosphorylation. Upregulation of TP53 and its downstream target gene DRAM1, but not CDKN1A/p21, was required for the autophagy induction in ERAL1 siRNA or CAP-treated cells. Altogether, these data indicate that autophagy is induced through the ROS-TP53-DRAM1 pathway in response to mitochondrial protein synthesis inhibition.
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Graeve, Olivia A; Fathi, Hoorshad; Kelly, James P; Saterlie, Michael S; Sinha, Kaustav; Rojas-George, Gabriel; Kanakala, Raghunath; Brown, David R; Lopez, Enrique A
2013-10-01
We present an analysis of reverse micelle stability in four model systems. The first two systems, composed of unstable microemulsions of isooctane, water, and Na-AOT with additions of either iron sulfate or yttrium nitrate, were used for the synthesis of iron oxide or yttrium oxide powders. These oxide powders were of nanocrystalline character, but with some level of agglomeration that was dependent on calcination temperature and cleaning procedures. Results show that even though the reverse micellar solutions were unstable, nanocrystalline powders with very low levels of agglomeration could be obtained. This effect can be attributed to the protective action of the surfactant on the surfaces of the powders that prevents neck formation until after all the surfactant has volatilized. A striking feature of the IR spectra collected on the iron oxide powders is the absence of peaks in the ~1715 cm(-1) to 1750 cm(-1) region, where absorption due to the symmetric C=O (carbonyl) stretching occurs. The lack of such peaks strongly suggests the carbonyl group is no longer free, but is actively participating in the surfactant-precipitate interaction. The final two microemulsion systems, containing CTAB as the surfactant, showed that loss of control of the reverse micelle synthesis process can easily occur when the amount of salt in the water domains exceeds a critical concentration. Both model systems eventually resulted in agglomerated powders of broad size distributions or particles that were large compared to the sizes of the reverse micelles, consistent with the notion that the microemulsions were not stable and the powders were precipitated in an uncontrolled fashion. This has implications for the synthesis of nanopowders by reverse micelle synthesis and provides a benchmark for process control if powders of the highest quality are desired. Copyright © 2013 Elsevier Inc. All rights reserved.
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Ejaz, Syeda Abida; Saeed, Aamer; Siddique, Muhammad Nasir; Nisa, Zaib Un; Khan, Samiullah; Lecka, Joanna; Sévigny, Jean; Iqbal, Jamshed
2017-02-01
Alkaline phosphatase (AP) and ecto-5'-nucleotidase (e5'NT) belong to same family that hydrolyze the extracellular nucleotides and ensure the bioavailability of nucleotides and nucleosides at purinergic receptors. During pathophysiological conditions, the over expression of AP and e5'NT lead to an increased production of adenosine that enhance tumor proliferation, invasiveness, neoangiogenesis and disrupts the body antitumor response. As both enzymes are abundantly expressed in above mentioned conditions, therefore it is of great interest to synthesize and develop potent inhibitors of these enzymes that augment the antitumor therapy. Herein we reported the synthesis and biological activity of a new series of chalcone-sulfonamide hybrids (4a-j). These derivatives were then evaluated for their inhibitory potential against two members of ecto-nucleotidase family, e5'NT (human and rat) and APs isozyme (intestinal and tissue nonspecific). Only six derivatives were found to inhibit both human and rat e5'NT enzymes. Compounds 4e and 4d showed maximum inhibition of human and rat e5'NT with an IC 50 ±SEM=0.26±0.01 and 0.33±0.004μM, respectively. Moreover, on APs, these derivatives were identified as the selective inhibitors of calf intestinal AP (c-IAP). The derivative 4a exhibited maximum inhibition of c-IAP with an IC 50 ±SEM=0.12±0.02μM. In conclusion, these chalcone-sulfonamide hybrids exhibited dual inhibition of both family of isozymes but was more selective towards c-IAP enzyme. Copyright © 2017 Elsevier Inc. All rights reserved.
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Effect of a hepatitis B virus inhibitor, NZ-4, on capsid formation.
Yang, Li; Wang, Ya-Juan; Chen, Hai-Jun; Shi, Li-Ping; Tong, Xian-Kun; Zhang, Yang-Ming; Wang, Gui-Feng; Wang, Wen-Long; Feng, Chun-Lan; He, Pei-Lan; Xu, Yi-Bin; Lu, Meng-Ji; Tang, Wei; Nan, Fa-Jun; Zuo, Jian-Ping
2016-01-01
During the hepatitis B virus (HBV) life cycle, nucleocapsid assembly is essential for HBV replication. Both RNA reverse transcription and DNA replication occur within the HBV nucleocapsid. HBV nucleocapsid is consisted of core protein (HBcAg), whose carboxy-terminal domain (CTD) contains an Arg-rich domain (ARD). The ARD of HBcAg does contribute to the encapsidation of pregenomic RNA (pgRNA). Previously, we reported a small-molecule, NZ-4, which dramatically reduced the HBV DNA level in an in vitro cell setting. Here, we explore the possible mechanisms by which NZ-4 inhibits HBV function. As an HBV inhibitor, NZ-4 leads to the formation of genome-free capsids, including a new population of capsid that runs faster on agarose gels. NZ-4's activity was dependent on the presence of the ARD I, containing at least one positively charged amino acid. NZ-4 might provide a new option for further development of HBV therapeutics for the treatment of chronic hepatitis B. Copyright © 2015. Published by Elsevier B.V.
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Lindenmayer, A; Schoen, H F
1967-08-01
The initiation of perithecia in the homothallic ascomycete Sordaria fimicola was completely suppressed, without seriously inhibiting vegetative growth, by growing the fungus on an agar medium containing one of the following additions: 1) 1 mum 5-fluorouracil, 2) 10 to 100 mum 6-azauracil, 8-azaguanine or 8-azaadenine, 3) 50 to 500 mum cyanide or azide, 4) 5% (w/v) casein hydrolysate. In contrast to the selective activity of the analogues of 3 RNA bases, whose inhibition could be reversed by the appropriate normal bases only, none of the analogues of thymine were active, neither were the thio-derivatives of RNA bases. Other inhibitors of RNA and protein synthesis, like actinomycin D, puromycin and cycloheximide, were also without selective activity, although the last of these inhibited perithecial maturation at 0.1 mum concentration but not initiation. Amino acid analogues were inactive, as were the metabolic inhibitors thiourea, 2,4-dinitrophenol and fluoride. The compounds which inhibited the formation of perithecia also lowered the branching frequency of leading hyphae, but not their linear growth rates. Consequently, the branch densities were diminished in their presence. Hypotheses to account for these findings are discussed in terms of inhibition of growth in general, of the synthesis of some specific messenger RNAs, and of RNA-mediated transport across membranes, the last of which seeming the most fruitful for further work.
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Dhar, T G Murali; Liu, Chunjian; Pitts, William J; Guo, Junquing; Watterson, Scott H; Gu, Henry; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Barrish, Joel C; Hollenbaugh, Diane; Iwanowicz, Edwin J
2002-11-04
A series of heterocyclic replacements for the central diamide moiety of 1, a potent small molecule inhibitor of inosine monophosphate dehydrogenase (IMPDH) were explored The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for these new series of inhibitors is given.
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[The specific enzyme inhibitors for potential therapeutic use].
Bretner, Maria
2015-01-01
Therapy for hepatitis C virus (HCV) initially consisted on administering ribavirin - having a broad spectrum of action - and pegylated interferon, and was only effective in 40-50% of patients. Appropriate was to find effective inhibitors of viral replication e.g. by inhibition of a viral enzyme, NTPase/helicase required in the process of translation and RNA replication of the HCV. We developed methods of synthesis of many compounds belonging to different groups - derivatives of nucleosides, benzotriazole, benzimidazole, tropolone and epirubicine. Some of the derivatives inhibit HCV helicase activity at low concentrations and reduces replication of the viral RNA in subgenomic replicon system. In the process of HCV replication casein kinase CK2 plays an important role. It regulates the level of phosphorylation of HCV protein NS5A, which affects the production of infectious virions of HCV. Effective and selective inhibitors of kinase CK2 could be of use in the treatment of HCV in combination with other drugs. CK2 kinase phosphorylates approximately 300 proteins that affect the growth, differentiation, proliferation or apoptosis. Elevated CK2 kinase activity has been observed in several types of cancer and other diseases, therefore, inhibitors of this enzyme are potential therapeutic importance, particularly for anti-cancer treatment. Research carried out in collaboration with prof. Shugar led to the synthesis of one of the most selective inhibitors of this enzyme which is 4,5,6,7-tetrabromo-1H-benzotriazole, used for the study of the role of kinase CK2 in a number of metabolic processes in tumor cells.
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Context memory formation requires activity-dependent protein degradation in the hippocampus.
Cullen, Patrick K; Ferrara, Nicole C; Pullins, Shane E; Helmstetter, Fred J
2017-11-01
Numerous studies have indicated that the consolidation of contextual fear memories supported by an aversive outcome like footshock requires de novo protein synthesis as well as protein degradation mediated by the ubiquitin-proteasome system (UPS). Context memory formed in the absence of an aversive stimulus by simple exposure to a novel environment requires de novo protein synthesis in both the dorsal (dHPC) and ventral (vHPC) hippocampus. However, the role of UPS-mediated protein degradation in the consolidation of context memory in the absence of a strong aversive stimulus has not been investigated. In the present study, we used the context preexposure facilitation effect (CPFE) procedure, which allows for the dissociation of context learning from context-shock learning, to investigate the role of activity-dependent protein degradation in the dHPC and vHPC during the formation of a context memory. We report that blocking protein degradation with the proteasome inhibitor clasto-lactacystin β-lactone (βLac) or blocking protein synthesis with anisomycin (ANI) immediately after context preexposure significantly impaired context memory formation. Additionally, we examined 20S proteasome activity at different time points following context exposure and saw that the activity of proteasomes in the dHPC increases immediately after stimulus exposure while the vHPC exhibits a biphasic pattern of proteolytic activity. Taken together, these data suggest that the requirement of increased proteolysis during memory consolidation is not driven by processes triggered by the strong aversive outcome (i.e., shock) normally used to support fear conditioning. © 2017 Cullen et al.; Published by Cold Spring Harbor Laboratory Press.
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Discovery of highly selective inhibitors of p38alpha.
Popa-Burke, Ioana; Birkos, Steve; Blackwell, Leonard; Cheatham, Lynn; Clark, Jennifer; Dickson, John K; Galasinski, Scott; Janzen, William P; Mendoza, Jose; Miller, Jennifer L; Mohney, Robert P; Steed, Paul M; Hodge, C Nicholas
2005-01-01
The p38 MAP kinases are a family of serine/threonine protein kinases that play a key role in cellular pathways leading to pro-inflammatory responses. We have developed and implemented a method for rapidly identifying and optimizing potent and selective p38alpha inhibitors, which is amenable to other targets and target classes. A diverse library of druggable, purified and quantitated molecules was assembled and standardized enzymatic assays were performed in a microfluidic format that provided very accurate and precise inhibition data allowing for development of SAR directly from the primary HTS. All compounds were screened against a collection of more than 60 enzymes (kinases, proteases and phosphatases), allowing for removal of promiscuous and non-selective inhibitors very early in the discovery process. Follow-up enzymological studies included measurement of concentration of compound in buffer, yielding accurate determination of K(i) and IC50 values, as well as mechanism of action. In addition, active compounds were screened against less desirable properties such as inhibition of the enzyme activity by aggregation, irreversible binding, and time-dependence. Screening of an 88,634-compound library through the above-described process led to the rapid identification of multiple scaffolds (>5 active compounds per scaffold) of potential drug leads for p38alpha that are highly selective against all other enzymes tested, including the three other p38 isoforms. Potency and selectivity data allowed prioritization of the identified scaffolds for optimization. Herein we present results around our 3-thio-1,2,4-triazole lead series of p38- selective inhibitors, including identification, SAR, synthesis, selectivity profile, enzymatic and cellular data in their progression towards drug candidates.
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Glucocorticoids and Polyamine Inhibitors Synergize to Kill Human Leukemic CEM Cells1
Miller, Aaron L; Johnson, Betty H; Medh, Rheem D; Townsend, Courtney M; Thompson, E Brad
2002-01-01
Abstract Glucocorticoids are well-known apoptotic agents in certain classes of lymphoid cell malignancies. Reduction of intracellular polyamine levels by use of inhibitors that block polyamine synthesis slows or inhibits growth of many cells in vitro. Several such inhibitors have shown efficacy in clinical trials, though the toxicity of some compounds has limited their usefulness. We have tested the effects of combinations of the glucocorticoid dexamethasone (Dex) and two polyamine inhibitors, difluoromethylornithine (DFMO) and methyl glyoxal bis guanylhydrazone (MGBG), on the clonal line of human acute lymphoblastic leukemia cells, CEM-C7-14. Dex alone kills these cells, though only after a delay of at least 24 hours. We also evaluated a partially glucocorticoid-resistant c-Myc-expressing CEM-C7-14 clone. We show that Dex downregulates ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine synthesis. Pretreatment with the ODC inhibitor DFMO, followed by addition of Dex, enhances steroid-evoked kill slightly. The combination of pretreatment with sublethal concentrations of both DFMO and the inhibitor of S-adenosylmethionine decarboxylase, MGBG, followed by addition of Dex, results in strong synergistic cell kill. Both the rapidity and extent of cell kill are enhanced compared to the effects of Dex alone. These results suggest that use of such combinations in vivo may result in apoptosis of malignant cells with lower overall toxicity. PMID:11922393
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Marco, José L; de los Ríos, Cristóbal; García, Antonio G; Villarroya, Mercedes; Carreiras, M Carmo; Martins, Carla; Eleutério, Ana; Morreale, Antonio; Orozco, M; Luque, F Javier
2004-05-01
The synthesis and the biological activity of compounds 5-40 as inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), as well as modulators of voltage-dependent Ca(2+) channels and nicotinic receptors, are described. These molecules are tacrine analogues, which have been prepared from polyfunctionalized 6-amino-5-cyano-4H-pyrans, 6-amino-5-cyano-pyridines and 5-amino-2-aryl-3-cyano-1,3-oxazoles via Friedländer reaction with selected cycloalkanones. These compounds are moderate acetylcholinesterase and butyrylcholinesterase inhibitors, the BuChE/AChE selectivity of the most active molecules ranges from 10.0 (compound 29) to 76.9 (compound 16). Interestingly, the 'oxazolo-tacrine' derivatives are devoid of any activity. All compounds showed an important inhibitory effect on the nicotinic acetylcholine receptor. Most of them also blocked L-type Ca(2+) channels, and three of them, 64, 19 and 67, the non-L type of Ca(2+) channels. Molecular modelling studies suggest that these compounds might bind at the peripheral binding site of AChE, which opens the possibility to design inhibitors able to bind at both, the catalytic and peripheral binding sites of the enzyme.
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BACTERIOPHAGE FORMATION WITHOUT BACTERIAL GROWTH
Price, Winston H.
1947-01-01
1. Iodoacetate, fluoride, and azide have been found to prevent the formation of phage and to inhibit the synthesis of ATP by Staphylococcus muscae. It is suggested that energy-rich phosphate is needed for the synthesis of phage. 2. Gramicidin prevented the formation of phage. 3. No differences were found between normal bacteria and phage-infected bacteria in the inorganic phosphate, adenosinetriphosphate, ribonucleic acid, and desoxyribonucleic acid content of the cells. 4. The mechanism of phage formation is discussed. PMID:18896936
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Monosaccharides as Scaffolds for the Synthesis of Novel Compounds
NASA Astrophysics Data System (ADS)
Murphy, Paul V.; Velasco-Torrijos, Trinidad
This chapter focuses on monosaccharides and scaffolds their derivatives as scaffolds for the synthesis of primarily bioactive compounds. Such carbohydrate derivatives have been designed to modulate mainly protein-protein and peptide-protein interactions although modulators of carbohydrate-protein and carbohydrate-nucleic acid interactions have also been of interest. The multiple hydroxyl groups that are present on saccharides have made pyranose, furanose and iminosugars ideal templates or scaffolds to which recognition or pharmacophoric groups can be grafted to generate novel compounds for medicinal chemistry. The synthesis of compounds for evaluations require strategies for regioselective reactions of saccharide hydroxyl groups and use of orthogonally stable protecting groups. Syntheses have been carried out on the solid phase and in solution. Also the use of uronic acids, amino sugars and sugar amino acids has facilitated the synthesis of peptidomimetics and prospecting libraries as they enable, through presence of amino or carboxylic acid groups, chemoselective approaches to be employed in solution and on solid phase. Sugar amino acids are readily incorporated, as peptide isosteres, to generate sugar-peptide hybrids or for the synthesis of novel carbopeptoids . The synthesis of new cyclic compounds, derived in part from saccharides, and their application as scaffolds is an emerging area and recent examples include spirocyclic compounds, benzodiazepine-saccharide hybrids and macrolide-saccharide hybrids. Potent bioactive saccharide derivatives have been identified that include enzyme inhibitors , somatostatin receptor ligands, integrin ligands, anti-viral compounds, shiga toxin inhibitors and cell growth inhibitors. Some saccharide derivatives have demonstrated improved cellular permeability when compared with peptides and are in clinical trials.
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Thach, Oscar; Mielczarek, Marcin; Ma, Cong; Kutty, Samuel K; Yang, Xiao; Black, David StC; Griffith, Renate; Lewis, Peter J; Kumar, Naresh
2016-03-15
The search for small molecules capable of inhibiting transcription initiation in bacteria has resulted in the synthesis of N,N'-disubstituted hydrazines and imine-carbohydrazides comprised of indole, pyridine, pyrrole, furan and thiophene using the respective trichloroacetyl derivatives, carbohydrazides and aldehydes. Replacement of the indole moiety by smaller heterocycles linked by CONHNC linkers afforded a broad variety of compounds efficiently targeting the RNA polymerase-σ(70)/σ(A) interaction as determined by ELISA and exhibiting increased inhibition of the growth of Escherichia coli compared to Bacillus subtilis in culture. The structural features of the synthesized transcription initiation inhibitors needed for antibacterial activity were identified employing molecular modelling and structure-activity relationship (SAR) studies. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Novel inhibitors of IMPDH: a highly potent and selective quinolone-based series.
Watterson, Scott H; Carlsen, Marianne; Dhar, T G Murali; Shen, Zhongqi; Pitts, William J; Guo, Junqing; Gu, Henry H; Norris, Derek; Chorba, John; Chen, Ping; Cheney, Daniel; Witmer, Mark; Fleener, Catherine A; Rouleau, Katherine; Townsend, Robert; Hollenbaugh, Diane L; Iwanowicz, Edwin J
2003-02-10
A series of novel quinolone-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are described.
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Inhibition of Dengue Virus RNA Synthesis by an Adenosine Nucleoside ▿ †
Chen, Yen-Liang; Yin, Zheng; Duraiswamy, Jeyaraj; Schul, Wouter; Lim, Chin Chin; Liu, Boping; Xu, Hao Ying; Qing, Min; Yip, Andy; Wang, Gang; Chan, Wai Ling; Tan, Hui Pen; Lo, Melissa; Liung, Sarah; Kondreddi, Ravinder Reddy; Rao, Ranga; Gu, Helen; He, Handan; Keller, Thomas H.; Shi, Pei-Yong
2010-01-01
We recently reported that (2R,3R,4R,5R)-2-(4-amino-pyrrolo[2,3-d]pyrimidin-7-yl)-3-ethynyl-5-hydroxy-methyl-tetrahydro-furan-3,4-diol is a potent inhibitor of dengue virus (DENV), with 50% effective concentration (EC50) and cytotoxic concentration (CC50) values of 0.7 μM and >100 μM, respectively. Here we describe the synthesis, structure-activity relationship, and antiviral characterization of the inhibitor. In an AG129 mouse model, a single-dose treatment of DENV-infected mice with the compound suppressed peak viremia and completely prevented death. Mode-of-action analysis using a DENV replicon indicated that the compound blocks viral RNA synthesis. Recombinant adenosine kinase could convert the compound to a monophosphate form. Suppression of host adenosine kinase, using a specific inhibitor (iodotubercidin) or small interfering RNA (siRNA), abolished or reduced the compound's antiviral activity in cell culture. Studies of rats showed that 14C-labeled compound was converted to mono-, di-, and triphosphate metabolites in vivo. Collectively, the results suggest that this adenosine inhibitor is phosphorylated to an active (triphosphate) form which functions as a chain terminator for viral RNA synthesis. PMID:20457821
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Sawdy, R J; Slater, D M; Dennes, W J; Sullivan, M H; Bennett, P R
2000-01-01
The aim of this study was to determine the relative contributions of cyclo-oxygenase (COX) types 1 and 2 to prostaglandin synthesis at term. Fetal membranes were collected from 6 pregnancies after elective caesarean section at term, prior to labour. The presence of COX-1 and COX-2 protein was determined using Western analysis. The relative contributions of the two isoforms of COX to prostaglandin synthesis were determined by incubation of fetal membrane discs with either a COX-2 selective inhibitor, SC236, or a COX-1 selective inhibitor, SC560, and measurement of prostaglandin release during 24 h using enzyme-linked immuno-sorbent assay (ELISA). Both COX-1 and COX-2 protein were demonstrated in amnion and chorion-decidua. The COX-2 selective inhibitor, SC-236, significantly reduced prostaglandin synthesis, both in its COX-2 specific and higher, non-specific concentration ranges. The COX-1 selective inhibitor, SC-560, had no effect upon prostaglandin synthesis in its COX-1 specific concentration range, but did significantly reduce prostaglandin synthesis at higher, non-selective concentrations. Fetal membranes contain both COX-1 and COX-2 at term, but only COX-2 contributes towards prostaglandin synthesis. COX-2 selective NSAI drugs will be as effective as non-selective agents in inhibition of fetal membrane prostaglandin synthesis and may represent a new strategy for tocolysis. Copyright 2000 Harcourt Publishers Ltd.
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NASA Astrophysics Data System (ADS)
Do, Bao Phuong Huu; Dung Nguyen, Ba; Duy Nguyen, Hoang; Nguyen, Phuong Tung
2013-12-01
We report the synthesis of magnetic iron oxide nanoparticles encapsulated in maleic acid-2-acrylamido-2-methyl-1-propanesulfonate based polymer. This composite nanoparticle is specified for the high-pressure/high-temperature (HPHT) oilfield scale inhibition application. The process includes a facile-ultrasound-supported addition reaction to obtain iron oxide nanoparticles with surface coated by oleic acid. Then via inverse microemulsion polymerization with selected monomers, the specifically designed copolymers have been formatted in nanoscale. The structure and morphology of obtained materials were characterized by transmission electron microscopy (TEM), x-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and the thermal stability. The effectiveness of synthesized compounds as a carbonate scale inhibitor was investigated by testing method NACE standard TM 03-074-95 at aging temperature of 70, 90 and 120 °C. The magnetic nanocomposite particles can be easily collected and detected demonstrating their superior monitoring ability, which is absent in the case of conventional copolymer-based scale inhibitor.
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In vitro screening for potential chemical inhibitors of ...
Control of thyroid hormone (TH) signaling in vertebrates is dependent upon multiple key events including iodide uptake, hormone synthesis, metabolism and elimination, to maintain proper homeostasis of the hormones. Deiodinase enzymes interconvert THs between less active and more active forms via release of iodide from the substrate hormones. The activity of deiodinases has been identified as an important endpoint to include in the context of screening chemicals for thyroid hormone disruption. To address the lack of data regarding the potential for chemicals to inhibit these enzymes a research effort was initially focused on human deiodinase type 1 (D1). We utilized an adenovirus expression system for production of D1 enzyme, established robust assay parameters for non-radioactive determination of iodide release by the Sandell-Kolthoff method, and employed a 96-well plate format for screening chemical libraries. An initial set of 19 chemicals was used to establish the assay. Included in this set was the known D1 inhibitor 6-propylthiouracil (used as a positive control). Over 1800 unique chemicals primarily from the EPA’s ToxCast phase 1_v2, phase 2, and e1K chemical libraries were tested in the screening assay. Chemicals were initially screened at a single high concentration of 200 µM to identify potential D1 inhibitors. The majority of the chemicals did not inhibit D1 activity in this initial screen as defined as a response of less than 20% inhibition c
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Vanini, Giancarlo; Watson, Christopher J; Lydic, Ralph; Baghdoyan, Helen A
2008-12-01
Many general anesthetics are thought to produce a loss of wakefulness, in part, by enhancing gamma-aminobutyric acid (GABA) neurotransmission. However, GABAergic neurotransmission in the pontine reticular formation promotes wakefulness. This study tested the hypotheses that (1) relative to wakefulness, isoflurane decreases GABA levels in the pontine reticular formation; and (2) pontine reticular formation administration of drugs that increase or decrease GABA levels increases or decreases, respectively, isoflurane induction time. To test hypothesis 1, cats (n = 5) received a craniotomy and permanent electrodes for recording the electroencephalogram and electromyogram. Dialysis samples were collected from the pontine reticular formation during isoflurane anesthesia and wakefulness. GABA levels were quantified using high-performance liquid chromatography. For hypothesis 2, rats (n = 10) were implanted with a guide cannula aimed for the pontine reticular formation. Each rat received microinjections of Ringer's (vehicle control), the GABA uptake inhibitor nipecotic acid, and the GABA synthesis inhibitor 3-mercaptopropionic acid. Rats were then anesthetized with isoflurane, and induction time was quantified as loss of righting reflex. Breathing rate was also measured. Relative to wakefulness, GABA levels were significantly decreased by isoflurane. Increased power in the electroencephalogram and decreased activity in the electromyogram caused by isoflurane covaried with pontine reticular formation GABA levels. Nipecotic acid and 3-mercaptopropionic acid significantly increased and decreased, respectively, isoflurane induction time. Nipecotic acid also increased breathing rate. Decreasing pontine reticular formation GABA levels comprises one mechanism by which isoflurane causes loss of consciousness, altered cortical excitability, muscular hypotonia, and decreased respiratory rate.
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Synthesis, antimalarial properties, and SAR studies of alkoxyurea-based HDAC inhibitors.
Hansen, Finn K; Skinner-Adams, Tina S; Duffy, Sandra; Marek, Linda; Sumanadasa, Subathdrage D M; Kuna, Krystina; Held, Jana; Avery, Vicky M; Andrews, Katherine T; Kurz, Thomas
2014-03-01
Histone deacetylase (HDAC) inhibitors are an emerging class of potential antimalarial drugs. We investigated the antiplasmodial properties of 16 alkoxyurea-based HDAC inhibitors containing various cap and zinc binding groups (ZBGs). Ten compounds displayed sub-micromolar activity against the 3D7 line of Plasmodium falciparum. Structure-activity relationship studies revealed that a hydroxamic acid ZBG is crucial for antiplasmodial activity, and that the introduction of bulky alkyl substituents to cap groups increases potency against asexual blood-stage parasites. We also demonstrate that selected compounds cause hyperacetylation of P. falciparum histone H4, indicating inhibition of one or more PfHDACs. To assess the selectivity of alkoxyurea-based HDAC inhibitors for parasite over normal mammalian cells, the cytotoxicity of representative compounds was evaluated against neonatal foreskin fibroblast (NFF) cells. The most active compound, 6-((3-(4-(tert-butyl)phenyl)ureido)oxy)-N-hydroxyhexanamide (1 e, Pf3D7 IC50 : 0.16 μM) was 31-fold more toxic against the asexual blood stages than towards normal mammalian cells. Moreover, a subset of four structurally diverse HDAC inhibitors revealed moderate activity against late-stage (IV-V) gametocytes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Synthesis, biological evaluation, and docking studies of gigantol analogs as calmodulin inhibitors.
Reyes-Ramírez, Adelfo; Leyte-Lugo, Martha; Figueroa, Mario; Serrano-Alba, Trinidad; González-Andrade, Martín; Mata, Rachel
2011-07-01
Several analogs of gigantol (1) were synthesized to evaluate their effect on the complexes Ca(2+)-calmodulin (CaM) and Ca(2+)-CaM-CaM sensitive phosphodiesterase 1 (PDE1). The compounds belong to four structural groups including, 1,2-diphenylethanes (2-11), diphenylmethanes (13-15), 1,3-diphenylpropenones (16-18), and 1,3-diphenylpropanes (20-22). In vitro enzymatic studies showed that all compounds except 11 inhibited the complex Ca(2+)-CaM-PDE1 with IC(50) values ranging from 9 to 146 μM. On the other hand, all analogs but 11, 12 and 15 quenched the extrinsic fluorescence of the CaM biosensor hCaM-M124C-mBBr to different extent, then revealing different affinities to CaM; their affinity constants (K(m)) values were in the range of 3-80 μM. Molecular modeling studies indicated that all these compounds bound to CaM at the same site that the classical inhibitors trifluoperazine (TFP) and chlorpromazine (CPZ). Some of these analogs could be worthy candidates for developing new anti-tumor, local anesthetics, antidepressants, antipsychotic, or smooth muscle relaxant drugs, with anti-CaM properties due to their good affinity to CaM and the straightforwardness of their synthesis. In addition they could be valuable tools for the study of Ca(2+)-CaM functions. Copyright © 2011 Elsevier Masson SAS. All rights reserved.
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Indanones as high-potency reversible inhibitors of monoamine oxidase.
Mostert, Samantha; Petzer, Anél; Petzer, Jacobus P
2015-05-01
Recent reports document that α-tetralone (3,4-dihydro-2H-naphthalen-1-one) is an appropriate scaffold for the design of high-potency monoamine oxidase (MAO) inhibitors. Based on the structural similarity between α-tetralone and 1-indanone, the present study involved synthesis of 34 1-indanone and related indane derivatives as potential inhibitors of recombinant human MAO-A and MAO-B. The results show that C6-substituted indanones are particularly potent and selective MAO-B inhibitors, with IC50 values ranging from 0.001 to 0.030 μM. C5-Substituted indanone and indane derivatives are comparatively weaker MAO-B inhibitors. Although the 1-indanone and indane derivatives are selective inhibitors of the MAO-B isoform, a number of homologues are also potent MAO-A inhibitors, with three homologues possessing IC50 values <0.1 μM. Dialysis of enzyme-inhibitor mixtures further established a selected 1-indanone as a reversible MAO inhibitor with a competitive mode of inhibition. It may be concluded that 1-indanones are promising leads for the design of therapies for neurodegenerative and neuropsychiatric disorders such as Parkinson's disease and depression. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Iwata, Y; Arisawa, M; Hamada, R; Kita, Y; Mizutani, M Y; Tomioka, N; Itai, A; Miyamoto, S
2001-05-24
Aldose reductase (AR) has been implicated in the etiology of diabetic complications. Due to the limited number of currently available drugs for the treatment of diabetic complications, we have carried out structure-based drug design and synthesis in an attempt to find new types of AR inhibitors. With the ADAM&EVE program, a three-dimensional database (ACD3D) was searched using the ligand binding site of the AR crystal structure. Out of 179 compounds selected through this search followed by visual inspection, 36 compounds were purchased and subjected to a biological assay. Ten compounds showed more than 40% inhibition of AR at a 15 microg/mL concentration. In a subsequent lead optimization, a series of analogues of the most active compound were synthesized based on the docking mode derived by ADAM&EVE. Many of these congeners exhibited higher activities compared to the mother compound. Indeed, the most potent, synthesized compound showed an approximately 20-fold increase in inhibitory activity (IC(50) = 0.21 vs 4.3 microM). Furthermore, a hydrophobic subsite was newly inferred, which would be useful for the design of inhibitors with improved affinity for AR.
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INVITED REVIEW: Inhibitors of myostatin as methods of enhancing muscle growth and development.
Chen, P R; Lee, K
2016-08-01
With the increasing demand for affordable, high-quality meat, livestock and poultry producers must continually find ways to maximize muscle growth in their animals without compromising palatability of the meat products. Muscle mass relies on myoblast proliferation during prenatal or prehatch stages and fiber hypertrophy through protein synthesis and nuclei donation by satellite cells after birth or hatch. Therefore, understanding the cellular and molecular mechanisms of myogenesis and muscle development is of great interest. Myostatin is a well-known negative regulator of muscle growth and development that inhibits proliferation and differentiation in myogenic cells as well as protein synthesis in existing muscle fibers. In this review, various inhibitors of myostatin activity or signaling are examined that may be used in animal agriculture for enhancing muscle growth. Myostatin inhibitors are relevant as potential therapies for muscle-wasting diseases and muscle weakness in humans and animals. Currently, there are no commercial myostatin inhibitors for agriculture or biomedical purposes because the safest and most effective option has yet to be identified. Further investigation of myostatin inhibitors and administration strategies may revolutionize animal production and the medical field.
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Roles of calcium/calmodulin-dependent kinase II in long-term memory formation in crickets.
Mizunami, Makoto; Nemoto, Yuko; Terao, Kanta; Hamanaka, Yoshitaka; Matsumoto, Yukihisa
2014-01-01
Ca(2+)/calmodulin (CaM)-dependent protein kinase II (CaMKII) is a key molecule in many systems of learning and memory in vertebrates, but roles of CaMKII in invertebrates have not been characterized in detail. We have suggested that serial activation of NO/cGMP signaling, cyclic nucleotide-gated channel, Ca(2+)/CaM and cAMP signaling participates in long-term memory (LTM) formation in olfactory conditioning in crickets, and here we show participation of CaMKII in LTM formation and propose its site of action in the biochemical cascades. Crickets subjected to 3-trial conditioning to associate an odor with reward exhibited memory that lasts for a few days, which is characterized as protein synthesis-dependent LTM. In contrast, animals subjected to 1-trial conditioning exhibited memory that lasts for only several hours (mid-term memory, MTM). Injection of a CaMKII inhibitor prior to 3-trial conditioning impaired 1-day memory retention but not 1-hour memory retention, suggesting that CaMKII participates in LTM formation but not in MTM formation. Animals injected with a cGMP analogue, calcium ionophore or cAMP analogue prior to 1-trial conditioning exhibited 1-day retention, and co-injection of a CaMKII inhibitor impaired induction of LTM by the cGMP analogue or that by the calcium ionophore but not that by the cAMP analogue, suggesting that CaMKII is downstream of cGMP production and Ca(2+) influx and upstream of cAMP production in biochemical cascades for LTM formation. Animals injected with an adenylyl cyclase (AC) activator prior to 1-trial conditioning exhibited 1-day retention. Interestingly, a CaMKII inhibitor impaired LTM induction by the AC activator, although AC is expected to be a downstream target of CaMKII. The results suggest that CaMKII interacts with AC to facilitate cAMP production for LTM formation. We propose that CaMKII serves as a key molecule for interplay between Ca(2+) signaling and cAMP signaling for LTM formation, a new role of CaMKII in
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Li, Sanfeng; Wei, Xiangjin; Ren, Yulong; Qiu, Jiehua; Jiao, Guiai; Guo, Xiuping; Tang, Shaoqing; Wan, Jianmin; Hu, Peisong
2017-01-01
Starch is the main storage carbohydrate in higher plants. Although several enzymes and regulators for starch biosynthesis have been characterized, a complete regulatory network for starch synthesis in cereal seeds remains elusive. Here, we report the identification and characterization of the rice Brittle1 (OsBT1) gene, which is expressed specifically in the developing endosperm. The osbt1 mutant showed a white-core endosperm and a significantly lower grain weight than the wild-type. The formation and development of compound starch granules in osbt1 was obviously defective: the amyloplast was disintegrated at early developmental stages and the starch granules were disperse and not compound in the endosperm cells in the centre region of osbt1 seeds. The total starch content and amylose content was decreased and the physicochemical properties of starch were altered. Moreover, the degree of polymerization (DP) of amylopectin in osbt1 was remarkably different from that of wild-type. Map-based cloning of OsBT1 indicated that it encodes a putatively ADP-glucose transporter. OsBT1 coded protein localizes in the amyloplast envelope membrane. Furthermore, the expression of starch synthesis related genes was also altered in the osbt1 mutant. These findings indicate that OsBT1 plays an important role in starch synthesis and the formation of compound starch granules. PMID:28054650
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Beaulieu, Pierre L; Gillard, James; Bailey, Murray D; Boucher, Colette; Duceppe, Jean-Simon; Simoneau, Bruno; Wang, Xiao-Jun; Zhang, Li; Grozinger, Karl; Houpis, Ioannis; Farina, Vittorio; Heimroth, Heidi; Krueger, Thomas; Schnaubelt, Jürgen
2005-07-22
(1R,2S)-1-Amino-2-vinylcyclopropanecarboxylic acid (vinyl-ACCA) is a key building block in the synthesis of potent inhibitors of the hepatitis C virus NS3 protease such as BILN 2061, which was recently shown to dramatically reduce viral load after administration to patients infected with HCV genotype 1. We have developed a scalable process that delivers derivatives of this unusual amino acid in >99% ee. The strategy was based on the dialkylation of a glycine Schiff base using trans-1,4-dibromo-2-butene as an electrophile to produce racemic vinyl-ACCA, which was subsequently resolved using a readily available, inexpensive esterase enzyme (Alcalase 2.4L). Factors that affect diastereoselection in the initial dialkylation steps were examined and the conditions optimized to deliver the desired diastereomer selectively. Product inhibition, which was encountered during the enzymatic resolution step, initially resulted in prolonged cycle times. Enrichment of racemic vinyl-ACCA through a chemical resolution via diastereomeric salt formation or the use of forcing conditions in the enzymatic reaction both led to improvements in throughput and the development of a viable process. The chemistry described herein was scaled up to produce multikilogram quantities of this building block.
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Structure–Activity Relationships and Molecular Modeling of Sphingosine Kinase Inhibitors
2013-01-01
The design, synthesis, and evaluation of the potency of new isoform-selective inhibitors of sphingosine kinases 1 and 2 (SK1 and SK2), the enzyme that catalyzes the phosphorylation of d-erythro-sphingosine to produce the key signaling lipid, sphingosine 1-phosphate, are described. Recently, we reported that 1-(4-octylphenethyl)piperidin-4-ol (RB-005) is a selective inhibitor of SK1. Here we report the synthesis of 43 new analogues of RB-005, in which the lipophilic tail, polar headgroup, and linker region were modified to extend the structure–activity relationship profile for this lead compound, which we explain using modeling studies with the recently published crystal structure of SK1. We provide a basis for the key residues targeted by our profiled series and provide further evidence for the ability to discriminate between the two isoforms using pharmacological intervention. PMID:24164513
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Structure-based optimization of Cephalothin-analogue boronic acids as β-lactamase inhibitors
Morandi, Stefania; Morandi, Federica; Caselli, Emilia; Shoichet, Brian K.; Prati, Fabio
2008-01-01
Boronic acids have proved to be promising selective inhibitors of β-lactamases, acting as transition state analogues. Starting from a previously described nanomolar inhibitor of AmpC β-lactamase, three new inhibitors were designed to gain interactions with highly conserved residues, such as Asn343, and to bind more tightly to the enzyme. Among these, one was obtained by stereoselective synthesis and succeeded in placing its anionic group into the carboxylate binding site of the enzyme, as revealed by X-ray crystallography of the complex inhibitor/AmpC. Nevertheless, it failed at improving affinity, when compared to the lead from which it was derived. The origins of this structural and energetic discrepancy are discussed. PMID:17997318
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Aptamer antagonists of myelin-derived inhibitors promote axon growth.
Wang, Yuxuan; Khaing, Zin Z; Li, Na; Hall, Brad; Schmidt, Christine E; Ellington, Andrew D
2010-03-16
Myelin of the adult central nervous system (CNS) is one of the major sources of inhibitors of axon regeneration following injury. The three known myelin-derived inhibitors (Nogo, MAG, and OMgp) bind with high affinity to the Nogo-66 receptor (NgR) on axons and limit neurite outgrowth. Here we show that RNA aptamers can be generated that bind with high affinity to NgR, compete with myelin-derived inhibitors for binding to NgR, and promote axon elongation of neurons in vitro even in the presence of these inhibitors. Aptamers may have key advantages over protein antagonists, including low immunogenicity and the possibility of ready modification during chemical synthesis for stability, signaling, or immobilization. This first demonstration that aptamers can directly influence neuronal function suggests that aptamers may prove useful for not only healing spinal cord and other neuronal damage, but may be more generally useful as neuromodulators.
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Aptamer Antagonists of Myelin-Derived Inhibitors Promote Axon Growth
Wang, Yuxuan; Khaing, Zin Z.; Li, Na; Hall, Brad; Schmidt, Christine E.; Ellington, Andrew D.
2010-01-01
Myelin of the adult central nervous system (CNS) is one of the major sources of inhibitors of axon regeneration following injury. The three known myelin-derived inhibitors (Nogo, MAG, and OMgp) bind with high affinity to the Nogo-66 receptor (NgR) on axons and limit neurite outgrowth. Here we show that RNA aptamers can be generated that bind with high affinity to NgR, compete with myelin-derived inhibitors for binding to NgR, and promote axon elongation of neurons in vitro even in the presence of these inhibitors. Aptamers may have key advantages over protein antagonists, including low immunogenicity and the possibility of ready modification during chemical synthesis for stability, signaling, or immobilization. This first demonstration that aptamers can directly influence neuronal function suggests that aptamers may prove useful for not only healing spinal cord and other neuronal damage, but may be more generally useful as neuromodulators. PMID:20300533
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Design and synthesis of 3,3'-biscoumarin-based c-Met inhibitors.
Xu, Jimin; Ai, Jing; Liu, Sheng; Peng, Xia; Yu, Linqian; Geng, Meiyu; Nan, Fajun
2014-06-14
A library of biscoumarin-based c-Met inhibitors was synthesized, based on optimization of 3,3'-biscoumarin hit 3, which was identified as a non-ATP competitive inhibitor of c-Met from a diverse library of coumarin derivatives. Among these compounds, 38 and 40 not only showed potent enzyme activities with IC50 values of 107 nM and 30 nM, respectively, but also inhibited c-Met phosphorylation in BaF3/TPR-Met and EBC-1 cells.
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Nishi, Kyoko; Mück-Seler, Dorotea; Hasegawa, Shu; Watanabe, Arata; Diksic, Mirko
2006-10-16
Serotonin (5-HT), norepinephrine (NE) and dopamine (DA) released from nerve terminals in the brain are primarily removed from the synaptic cleft by a reuptake mechanism. In part, the homeostasis is maintained by monoamine oxidase (MAO) deamination achieved primarily intracellularly. The present study's aim was to examine the effect of the acute administration of the MAO inhibitors, moclobemide (a MAO-A inhibitor) and deprenyl (a MAO-B inhibitor), on 5-HT synthesis rates, measured in discrete regions of the rat brain by an autoradiographic method, using alpha-[14C]methyl-l-tryptophan as a tracer. MAO inhibitors have different effects on 5-HT synthesis rates in the cell bodies and areas of the nerve terminals. Moclobemide (10 mg/kg, i.p. 30 min before the tracer injection) and deprenyl (3 mg/kg, i.p. 2 h before the tracer injection) decreased the 5-HT synthesis rates in the dorsal (-18% and -22%) and median (-22% and -33%) raphe, respectively. Moclobemide also significantly decreased 5-HT synthesis in the entire nerve terminal areas investigated. The reductions were between 23% (cingulate cortex) and 50% (locus coeruleus). Deprenyl did not significantly affect 5-HT synthesis in the nerve terminals. The present results suggest that MAO-A, and to a lesser extent, MAO-B, are involved in the regulation of 5-HT synthesis in the rat brain. The mechanism(s) of MAO inhibitors' action on 5-HT synthesis in the raphe nuclei are probably related to an increase in the extraneuronal 5-HT concentration and also to the interaction between the serotonergic and catecholaminergic neurons. The reduction of 5-HT synthesis in the raphe nuclei likely occurs by an action of extracellular 5-HT via the dendritic autoreceptors with a possible contribution from the action of extracellular DA and NE. In the terminal regions, the most likely mechanism is via the presynaptic autoreceptors through which elevated extraneuronal 5-HT acts on synthesis control. However, there is also a possibility that
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NASA Technical Reports Server (NTRS)
Fanelli, Michael N.; O'Connell, Robert W.; Thuan, Trinh X.
1988-01-01
An initial attempt to apply optimizing spectral synthesis techniques to the far-UV spectra of blue compact galaxies (BCGs) is presented. The far-UV absorption-line spectra of the galaxies are clearly composite, with the signatures of the main-sequence types between O3 and mid-A. Most of the low-ionization absorption lines have a stellar origin. The Si IV and C IV features in several objects have P Cygni profiles. In Haro I the strength of Si IV indicates a significant blue supergiant population. The metal-poor blue compact dwarf Mrk 209 displays weak absorption lines, evidence that the stellar component has the same low metallicity as observed in the ionized gas. Good fits to the data are obtained the technique of optimizing population synthesis. The solutions yield stellar luminosity functions which display large discontinuities, indicative of discrete star formation episodes or bursts. The amount of UV extinction is low.
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Richter, Beatrice; Haller, Jacqueline; Haffner, Dieter; Leifheit-Nestler, Maren
2016-09-01
Chronic kidney disease (CKD) is a state of Klotho deficiency and excess of the phosphaturic hormone fibroblast growth factor 23 (FGF23). Both dysregulations were shown to be associated with endothelial dysfunction in humans, but direct vascular effects of FGF23 remain largely elusive. In vitro experiments were performed to assess the effects of FGF23 (10 ng/mL) in relation to its co-receptor Klotho on nitric oxide (NO) synthesis and reactive oxygen species (ROS) formation and detoxification in human coronary artery endothelial cells (HCAEC). Membrane-bound Klotho is expressed in HCAEC, and FGF23 increases the expression of the Klotho shedding protease ADAM17, and consequently the secretion of soluble Klotho. FGF23 activates FGF receptor 1 and stimulates NO release via Akt-dependent activation of endothelial NO synthase (eNOS). Both FGF receptor (FGFR)-dependent ROS formation via activation of NADPH oxidase 2 (Nox2) as well as ROS degradation via superoxide dismutase 2 (SOD2) and catalase (CAT) is stimulated by FGF23. Pre-incubation with a Klotho inhibitor blunts the FGF23-stimulated Akt-eNOS activation and NO synthesis, and decreases ROS degradation by blocking SOD2 and CAT enzymes, whereas FGF23-stimulated ROS synthesis via Nox2 is unaffected, resulting in low NO bioavailability and increased oxidative stress. Our data indicate that in the presence of Klotho, FGF23 induces NO release in HCAEC and its stimulating effects on ROS production are counterbalanced by increased ROS degradation. In states of Klotho deficiency, e.g., CKD, FGF23-mediated NO synthesis is blunted and ROS formation overrules ROS degradation. Thus, FGF23 excess may primarily promote oxidative stress and thus endothelial dysfunction.
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Synthesis and evaluation of phosphorus containing, specific CDK9/CycT1 inhibitors.
Németh, Gábor; Greff, Zoltán; Sipos, Anna; Varga, Zoltán; Székely, Rita; Sebestyén, Mónika; Jászay, Zsuzsa; Béni, Szabolcs; Nemes, Zoltán; Pirat, Jean-Luc; Volle, Jean-Noël; Virieux, David; Gyuris, Ágnes; Kelemenics, Katalin; Ay, Eva; Minarovits, Janos; Szathmary, Susan; Kéri, György; Orfi, László
2014-05-22
Although there is a significant effort in the design of a selective CDK9/CycT1 inhibitor, no compound has been proven to be a specific inhibitor of this kinase so far. The aim of this research was to develop novel and selective phosphorus containing CDK9/CycT1 inhibitors. Molecules bearing phosphonamidate, phosphonate, and phosphinate moieties were synthesized. Prepared compounds were evaluated in an enzymatic CDK9/CycT1 assay. The most potent molecules were tested in cell-based toxicity and HIV proliferation assays. Selectivity of shortlisted compounds against CDKs and other kinases was tested. The best compound was shown to be a highly specific, ATP-competitive inhibitor of CDK9/CycT1 with antiviral activity.
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Wang, Ling; Wang, Yu; Tian, Yiguang; Shang, Jinling; Sun, Xiaoou; Chen, Hongzhuan; Wang, Hao; Tan, Wen
2017-01-01
A series of novel chalcone-rivastigmine hybrids were designed, synthesized, and tested in vitro for their ability to inhibit human acetylcholinesterase and butyrylcholinesterase. Most of the target compounds showed hBChE selective activity in the micro- and submicromolar ranges. The most potent compound 3 exhibited comparable IC 50 to the commercially available drug (rivastigmine). To better understand their structure activity relationships (SAR) and mechanisms of enzyme-inhibitor interactions, kinetic and molecular modeling studies including molecular docking and molecular dynamics (MD) simulations were carried out. Furthermore, compound 3 blocks the formation of reactive oxygen species (ROS) in SH-SY5Y cells and shows the required druggability and low cytotoxicity, suggesting this hybrid is a promising multifunctional drug candidate for Alzheimer's disease (AD) treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Gehringer, Heike; Von der Helm, Klaus; Seelmeir, Sigrid; Weissbrich, Benedikt; Eberle, Josef; Nitschko, Hans
2003-05-01
A novel phenotypic assay, based on recombinant expression of the HIV-1-protease was developed and evaluated; it monitors the formation of resistance to protease inhibitors. The HIV-1 protease-encoding region from the blood sample of patients was amplified, ligated into the expression vector pBD2, and recombinantly expressed in Escherichia coli TG1 cells. The resulting recombinant enzyme was purified by a newly developed one-step acid extraction protocol. The protease activity was determined in presence of five selected HIV protease inhibitors and the 50% inhibitory concentration (IC(50)) to the respective protease inhibitors determined. The degree of resistance was expressed in terms of x-fold increase in IC(50) compared to the IC(50) value of an HIV-1 wild type protease preparation. The established test system showed a reproducible recombinant expression of each individual patients' HIV-1 protease population. Samples of nine clinically well characterised HIV-1-infected patients with varying degrees of resistance were analysed. There was a good correlation between clinical parameters and the results obtained by this phenotypic assay. For the majority of patients a blind genotypic analysis of the patients' protease domain revealed a fair correlation to the results of the phenotypic assay. In a minority of patients our phenotypic results diverged from the genotypic ones. This novel phenotypic assay can be carried out within 8-10 days, and offers a significant advantage in time to the current employed phenotypic tests.
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Synthesis of gallinamide A analogues as potent falcipain inhibitors and antimalarials.
Conroy, Trent; Guo, Jin T; Elias, Nabiha; Cergol, Katie M; Gut, Jiri; Legac, Jennifer; Khatoon, Lubna; Liu, Yang; McGowan, Sheena; Rosenthal, Philip J; Hunt, Nicholas H; Payne, Richard J
2014-12-26
Analogues of the natural product gallinamide A were prepared to elucidate novel inhibitors of the falcipain cysteine proteases. Analogues exhibited potent inhibition of falcipain-2 (FP-2) and falcipain-3 (FP-3) and of the development of Plasmodium falciparum in vitro. Several compounds were equipotent to chloroquine as inhibitors of the 3D7 strain of P. falciparum and maintained potent activity against the chloroquine-resistant Dd2 parasite. These compounds serve as promising leads for the development of novel antimalarial agents.
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Stereoselective synthesis of an active metabolite of the potent PI3 kinase inhibitor PKI-179.
Chen, Zecheng; Venkatesan, Aranapakam M; Dos Santos, Osvaldo; Delos Santos, Efren; Dehnhardt, Christoph M; Ayral-Kaloustian, Semiramis; Ashcroft, Joseph; McDonald, Leonard A; Mansour, Tarek S
2010-03-05
The synthesis and stereochemical determination of 1-(4-(4-((1R,5R,6R)-6-hydroxy-3-oxa-8-azabicyclo[3.2.1]octan-8-yl)-6-morpholino-1,3,5-triazin-2-yl)phenyl)-3-(pyridin-4-yl)urea (2), an active metabolite of the potent PI3 kinase inhibitor PKI-179 (1), is described. Stereospecific hydroboration of the double bond of 2,5-dihydro-1H-pyrrole 8 gave the 2,3-trans alcohol 9 exclusively. The configuration of the 3-hydroxyl group in 9 was inverted by an oxidation and stereoselective reduction sequence to give the corresponding 2,3-cis isomer 23. Both exo (21) and endo (27) isomers of the metabolite 2 were prepared via a practical synthetic route from 9 and 23, respectively, and the stereochemistry of 2 was determined to be endo. The endo isomer (27) was separated into two enantiomers 28 and 29 by chiral HPLC. Compound 2 was found to be enantiomerically pure and identical to the enantiomer 28. The absolute stereochemistry of the enantiomer 28 was determined by Mosher's method, thus establishing the stereochemistry of the active metabolite 2.
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Structure-based design, synthesis and biological evaluation of β-glucuronidase inhibitors
NASA Astrophysics Data System (ADS)
Khan, Khalid M.; Ambreen, Nida; Taha, Muhammad; Halim, Sobia A.; Zaheer-ul-Haq; Naureen, Shagufta; Rasheed, Saima; Perveen, Shahnaz; Ali, Sajjad; Choudhary, Mohammad Iqbal
2014-05-01
Using structure-based virtual screening approach, a coumarin derivative ( 1) was identified as β-glucuronidase inhibitor. A focused library of coumarin derivatives was synthesized by eco-benign version of chemical reaction, and all synthetic compounds were characterized by using spectroscopy. These compounds were found to be inhibitor of β-glucuronidase with IC50 values in a micromolar range. All synthetic compounds exhibited interesting inhibitory activity against β-glucuronidase, however, their potency varied substantially from IC50 = 9.9-352.6 µM. Of twenty-one compounds, four exhibited a better inhibitory profile than the initial hit 1. Interestingly, compounds 1e, 1k, 1n and 1p exhibited more potency than the standard inhibitor with IC50 values 34.2, 21.4, 11.7, and 9.9 µM, respectively. We further studied their dose responses and also checked our results by using detergent Triton ×-100. We found that our results are true and not affected by detergent.
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Structure-based design, synthesis and biological evaluation of β-glucuronidase inhibitors.
Khan, Khalid M; Ambreen, Nida; Taha, Muhammad; Halim, Sobia A; Zaheer-ul-Haq; Naureen, Shagufta; Rasheed, Saima; Perveen, Shahnaz; Ali, Sajjad; Choudhary, Mohammad Iqbal
2014-05-01
Using structure-based virtual screening approach, a coumarin derivative (1) was identified as β-glucuronidase inhibitor. A focused library of coumarin derivatives was synthesized by eco-benign version of chemical reaction, and all synthetic compounds were characterized by using spectroscopy. These compounds were found to be inhibitor of β-glucuronidase with IC50 values in a micromolar range. All synthetic compounds exhibited interesting inhibitory activity against β-glucuronidase, however, their potency varied substantially from IC50 = 9.9-352.6 µM. Of twenty-one compounds, four exhibited a better inhibitory profile than the initial hit 1. Interestingly, compounds 1e, 1k, 1n and 1p exhibited more potency than the standard inhibitor with IC50 values 34.2, 21.4, 11.7, and 9.9 µM, respectively. We further studied their dose responses and also checked our results by using detergent Triton ×-100. We found that our results are true and not affected by detergent.
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NASA Astrophysics Data System (ADS)
Peng, Jiaoyu; Bian, Shaoju; Lin, Feng; Wang, Liping; Dong, Yaping; Li, Wu
2017-10-01
The synthesis of pinnoite (MgB2O(OH)6) in boron-containing brine was established with a novel dilution method. Effects of temperature, precipitation time, boron concentration and mass dilution ratio on the formation of pinnoite were investigated. The products obtained were characterized by X-ray diffraction (XRD), Raman, thermogravimetric and differential scanning calorimeter (TG-DSC), and scanning electron microscopy. The transformation mechanism of pinnoite with different dilution ratios was assumed by studying the crystal growth of pinnoite. The results showed that pinnoite was synthesized above 60 °C in the diluted brine. There were two reaction steps - precipitation of amorphous solid and the formation of pinnoite crystals - during the whole reaction process of pinnoite when the dilution ratio is more than 1.0 at 80 °C. While in the 0.5 diluted brine, only one reaction step of pinnoite crystal formation was observed and its transformation mechanism was discussed based on dissociation of polyborates in brine. Besides, the origin of pinnoite mineral deposited on salt lake bottom was proposed.
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Swenson, P. A.; Setlow, R. B.
1970-01-01
Induced formation of tryptophanase in Escherichia coli B/r is temporarily inhibited by near-ultraviolet (UV) irradiation. The inhibition is greater when irradiation is at 5 C than when at room temperature. Hence, the inhibition is the result of a photochemical, rather than photoenzymatic, alteration of some cellular component. The action spectrum has a peak in the region of 334 nm and is similar to that for growth delay. However, inhibition of tryptophanase formation is more sensitive to near-UV irradiation than are growth, respiration, and the induced formation of β-galactosidase. Thus, for tryptophanase the lack of formation cannot be due to general inhibition of metabolism. Pyridoxal phosphate absorbs in the near-UV region of the spectrum and is a cofactor for tryptophanase, but this enzyme in induced cells is not inactivated by near UV-radiations. An experiment in which toluene-treated suspensions from irradiated and unirradiated cells were mixed showed that irradiation does not cause the formation of an inhibitor of tryptophanase activity. The possibility remains that the absorption of radiant energy by pyridoxal phosphate interferes with the synthesis of tryptophanase. PMID:4914082
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Synthesis of pyrimidin-2-one nucleosides as acid-stable inhibitors of cytidine deaminase.
Kim, C H; Marquez, V E; Mao, D T; Haines, D R; McCormack, J J
1986-08-01
One of the problems encountered in the use of tetrahydrouridine (THU, 2) and saturated 2-oxo-1,3-diazepine nucleosides as orally administered cytidine deaminase (CDA) inhibitors is their acid instability. Under acid conditions these compounds are rapidly converted into inactive ribopyranoside forms. A solution this problem was sought by functionalizing the acid-stable but less potent CDA inhibitor 1-beta-D-ribofuranosyl-2(1H)-pyrimidinone (1) with the hope of increasing its potency to the level achieved with THU. The selection of the hydroxymethyl substituent at C-4, which led to the synthesis of 4-(hydroxymethyl)-1-beta-D-ribofuranosyl-2(1H)-pyrimidinone (10), 3,4-dihydro-4-(hydroxymethyl)-1-beta-D-ribofuranosyl-2(1H)-pyrimidinone (7), and 3,4,5,6-tetrahydro-4-(dihydroxymethyl)-1-beta-D-ribofuranosyl-2(1H)-p yrimidinone (28) was based on the transition-state (TS) concept. The key intermediate precursor, 4-[(benzoyloxy)methyl]-1-(2,3,5-tri-O-benzoyl-beta-D-ribofuranosyl)-2(H) -pyrimidinone (24), was obtained via the classical Hilbert-Johnson reaction between 2-methoxy-4-[(benzoyloxy)methyl]pyrimidine (20) and 2,3,5-tri-O-benzoyl-1-D-ribofuranosyl bromide (21). Deprotection of 24 afforded compound 10, while its sodium borohydride reduction products afforded compounds 7 and 28 after removal of the blocking groups. Syntheses of 3,4-dihydro-1-beta-D-ribofuranosyl-2(1H)-pyrimidinone (9) and 3,6-dihydro-1-beta-D-ribofuranosyl-2(1H)-pyrimidinone (8), which lack the hydroxymethyl substituent, was accomplished in a similar fashion. The new compounds bearing the hydroxymethyl substituent were more acid stable than THU, and their CDA inhibitory potency, expressed in terms of Ki values, spanned from 10(-4) to 10(-7) M in a manner consistent with the TS theory. Compound 7, in particular, was superior to its parent 1 and equipotent to THU (Ki = 4 X 10(-7) M) when examined against mouse kidney CDA. The superior acid stability of this compound coupled to its potent inhibitory
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FAITH – Fast Assembly Inhibitor Test for HIV
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hadravová, Romana; Rumlová, Michaela, E-mail: michaela.rumlova@vscht.cz; Department of Biotechnology, University of Chemistry and Technology, Prague, Technická 5, 166 28 Prague
Due to the high number of drug-resistant HIV-1 mutants generated by highly active antiretroviral therapy (HAART), there is continuing demand for new types of inhibitors. Both the assembly of the Gag polyprotein into immature and mature HIV-1 particles are attractive candidates for the blocking of the retroviral life cycle. Currently, no therapeutically-used assembly inhibitor is available. One possible explanation is the lack of a reliable and simple assembly inhibitor screening method. To identify compounds potentially inhibiting the formation of both types of HIV-1 particles, we developed a new fluorescent high-throughput screening assay. This assay is based on the quantification ofmore » the assembly efficiency in vitro in a 96-well plate format. The key components of the assay are HIV-1 Gag-derived proteins and a dual-labelled oligonucleotide, which emits fluorescence only when the assembly of retroviral particles is inhibited. The method was validated using three (CAI, BM2, PF74) reported assembly inhibitors. - Highlights: • Allows screening of assembly inhibitors of both mature and immature HIV-1 particles. • Based on Gag-derived proteins with CA in mature or immature conformation. • Simple and sensitive method suitable for high-throughput screening of inhibitors. • Unlike in other HIV assembly methods, works under physiological conditions. • No washing steps are necessary.« less
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Baquero-Pérez, Belinda; Whitehouse, Adrian
2015-01-01
Kaposi’s sarcoma-associated herpesvirus (KSHV) is an oncogenic herpesvirus associated with various AIDS-related malignancies. Like other herpesviruses, multiple processes required for KSHV lytic replication, including viral transcription, viral DNA synthesis and capsid assembly occur in virus-induced intranuclear structures, termed replication and transcription compartments (RTCs). Here we utilised a novel methodology, combining subcellular fractionation and quantitative proteomics, to identify cellular proteins which are recruited to KSHV-induced RTCs and thus play a key role in KSHV lytic replication. We show that several isoforms of the HSP70 chaperone family, Hsc70 and iHsp70, are redistributed from the cytoplasm into the nucleus coinciding with the initial formation of KSHV-induced RTCs. We demonstrate that nuclear chaperone foci are dynamic, initially forming adjacent to newly formed KSHV RTCs, however during later time points the chaperones move within KSHV RTCs and completely co-localise with actively replicating viral DNA. The functional significance of Hsp70 isoforms recruitment into KSHV RTCs was also examined using the specific Hsp70 isoform small molecule inhibitor, VER-155008. Intriguingly, results highlight an essential role of Hsp70 isoforms in the KSHV replication cycle independent of protein stability and maturation. Notably, inhibition of Hsp70 isoforms precluded KSHV RTC formation and RNA polymerase II (RNAPII) relocalisation to the viral genome leading to the abolishment of global KSHV transcription and subsequent viral protein synthesis and DNA replication. These new findings have revealed novel mechanisms that regulate KSHV lytic replication and highlight the potential of HSP70 inhibitors as novel antiviral agents. PMID:26587836
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Zaware, Nilesh; Kisliuk, Roy; Bastian, Anja; Ihnat, Michael A; Gangjee, Aleem
2017-04-01
In an effort to optimize the structural requirements for combined cytostatic and cytotoxic effects in single agents, a series of 5-(arylthio)-9H-pyrimido[4,5-b]indole-2,4-diamines 3-7 were synthesized and evaluated as inhibitors of receptor tyrosine kinases (RTKs) as well as thymidylate synthase (TS). The synthesis of these compounds involved the nucleophilic displacement of the common intermediate 5-bromo/5-chloro-9H-pyrimido[4,5-b]indole-2,4-diamine with appropriate aryl thiols. A novel four step synthetic scheme to the common intermediate was developed which is more efficient relative to the previously reported six-step sequence. Biological evaluation of these compounds indicated dual activity in RTKs and human TS (hTS). In the VEGFR-2 assay, compound 5 was equipotent to the standard compound semaxanib and was better than standard TS inhibitor pemetrexed, in the hTS assay. Compounds 3, 6 and 7 were nanomolar inhibitors of hTS and were several fold better than pemetrexed. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Busot, Grethel Yanet; McClure, Bruce; Ibarra-Sánchez, Claudia Patricia; Jiménez-Durán, Karina; Vázquez-Santana, Sonia; Cruz-García, Felipe
2008-01-01
After landing on a wet stigma, pollen grains hydrate and germination generally occurs. However, there is no certainty of the pollen tube growth through the style to reach the ovary. The pistil is a gatekeeper that evolved in many species to recognize and reject the self-pollen, avoiding endogamy and encouraging cross-pollination. However, recognition is a complex process, and specific factors are needed. Here the isolation and characterization of a stigma-specific protein from N. alata, NaStEP (N. alata Stigma Expressed Protein), that is homologous to Kunitz-type proteinase inhibitors, are reported. Activity gel assays showed that NaStEP is not a functional serine proteinase inhibitor. Immunohistochemical and protein blot analyses revealed that NaStEP is detectable in stigmas of self-incompatible (SI) species N. alata, N. forgetiana, and N. bonariensis, but not in self-compatible (SC) species N. tabacum, N. plumbaginifolia, N. benthamiana, N. longiflora, and N. glauca. NaStEP contains the vacuolar targeting sequence NPIVL, and immunocytochemistry experiments showed vacuolar localization in unpollinated stigmas. After self-pollination or pollination with pollen from the SC species N. tabacum or N. plumbaginifolia, NaStEP was also found in the stigmatic exudate. The synthesis and presence in the stigmatic exudate of this protein was strongly induced in N. alata following incompatible pollination with N. tabacum pollen. The transfer of NaStEP to the stigmatic exudate was accompanied by perforation of the stigmatic cell wall, which appeared to release the vacuolar contents to the apoplastic space. The increase in NaStEP synthesis after pollination and its presence in the stigmatic exudates suggest that this protein may play a role in the early pollen–stigma interactions that regulate pollen tube growth in Nicotiana. PMID:18689443
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Busot, Grethel Yanet; McClure, Bruce; Ibarra-Sánchez, Claudia Patricia; Jiménez-Durán, Karina; Vázquez-Santana, Sonia; Cruz-García, Felipe
2008-01-01
After landing on a wet stigma, pollen grains hydrate and germination generally occurs. However, there is no certainty of the pollen tube growth through the style to reach the ovary. The pistil is a gatekeeper that evolved in many species to recognize and reject the self-pollen, avoiding endogamy and encouraging cross-pollination. However, recognition is a complex process, and specific factors are needed. Here the isolation and characterization of a stigma-specific protein from N. alata, NaStEP (N. alata Stigma Expressed Protein), that is homologous to Kunitz-type proteinase inhibitors, are reported. Activity gel assays showed that NaStEP is not a functional serine proteinase inhibitor. Immunohistochemical and protein blot analyses revealed that NaStEP is detectable in stigmas of self-incompatible (SI) species N. alata, N. forgetiana, and N. bonariensis, but not in self-compatible (SC) species N. tabacum, N. plumbaginifolia, N. benthamiana, N. longiflora, and N. glauca. NaStEP contains the vacuolar targeting sequence NPIVL, and immunocytochemistry experiments showed vacuolar localization in unpollinated stigmas. After self-pollination or pollination with pollen from the SC species N. tabacum or N. plumbaginifolia, NaStEP was also found in the stigmatic exudate. The synthesis and presence in the stigmatic exudate of this protein was strongly induced in N. alata following incompatible pollination with N. tabacum pollen. The transfer of NaStEP to the stigmatic exudate was accompanied by perforation of the stigmatic cell wall, which appeared to release the vacuolar contents to the apoplastic space. The increase in NaStEP synthesis after pollination and its presence in the stigmatic exudates suggest that this protein may play a role in the early pollen-stigma interactions that regulate pollen tube growth in Nicotiana.
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Kharel, Yugesh; Raje, Mithun R.; Gao, Ming; Tomsig, Jose L.; Lynch, Kevin R.; Santos, Webster L.
2015-01-01
Sphingosine 1-phosphate (S1P) is a pleiotropic signaling molecule that acts as a ligand for five G-protein coupled receptors (S1P1–5) whose downstream effects are implicated in a variety of important pathologies including sickle cell disease, cancer, inflammation, and fibrosis. The synthesis of S1P is catalyzed by sphingosine kinase (SphK) isoforms 1 and 2, and hence, inhibitors of this phosphorylation step are pivotal in understanding the physiological functions of SphKs. To date, SphK1 and 2 inhibitors with the potency, selectivity, and in vivo stability necessary to determine the potential of these kinases as therapeutic targets are lacking. Herein, we report the design, synthesis, and structure–activity relationship studies of guanidine-based SphK inhibitors bearing an oxadiazole ring in the scaffold. Our studies demonstrate that SLP120701, a SphK2-selective inhibitor (Ki = 1 μM), decreases S1P levels in histiocytic lymphoma (U937) cells. Surprisingly, homologation with a single methylene unit between the oxadiazole and heterocyclic ring afforded a SphK1-selective inhibitor in SLP7111228 (Ki = 48 nM), which also decreased S1P levels in cultured U937 cells. In vivo application of both compounds, however, resulted in contrasting effect in circulating levels of S1P. Administration of SLP7111228 depressed blood S1P levels while SLP120701 increased levels of S1P. Taken together, these compounds provide an in vivo chemical toolkit to interrogate the effect of increasing or decreasing S1P levels and whether such a maneuver can have implications in disease states. PMID:25643074
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Inhibition of Fatty Acid Synthesis Induces Apoptosis of Human Pancreatic Cancer Cells.
Nishi, Koji; Suzuki, Kenta; Sawamoto, Junpei; Tokizawa, Yuma; Iwase, Yumiko; Yumita, Nagahiko; Ikeda, Toshihiko
2016-09-01
Cancer cells tend to have a high requirement for lipids, including fatty acids, cholesterol and triglyceride, because of their rapid proliferative rate compared to normal cells. In this study, we investigated the effects of inhibition of lipid synthesis on the proliferation and viability of human pancreatic cancer cells. Of the inhibitors of lipid synthesis that were tested, 5-(tetradecyloxy)-2-furoic acid (TOFA), which is an inhibitor of acetyl-CoA carboxylase, and the fatty acid synthase (FAS) inhibitors cerulenin and irgasan, significantly suppressed the proliferation of MiaPaCa-2 and AsPC-1 cells. Treatment of MiaPaCa-2 cells with these inhibitors significantly increased the number of apoptotic cells. In addition, TOFA increased caspase-3 activity and induced cleavage of poly (ADP-ribose) polymerase in MiaPaCa-2 cells. Moreover, addition of palmitate to MiaPaCa-2 cells treated with TOFA rescued cells from apoptotic cell death. These results suggest that TOFA induces apoptosis via depletion of fatty acids and that, among the various aspects of lipid metabolism, inhibition of fatty acid synthesis may be a notable target for the treatment of human pancreatic cancer cells. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.
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Discovery of Ecopladib, an indole inhibitor of cytosolic phospholipase A2alpha.
Lee, Katherine L; Foley, Megan A; Chen, Lihren; Behnke, Mark L; Lovering, Frank E; Kirincich, Steven J; Wang, Weiheng; Shim, Jaechul; Tam, Steve; Shen, Marina W H; Khor, Soopeang; Xu, Xin; Goodwin, Debra G; Ramarao, Manjunath K; Nickerson-Nutter, Cheryl; Donahue, Frances; Ku, M Sherry; Clark, James D; McKew, John C
2007-03-22
The synthesis and structure-activity relationship of a series of indole inhibitors of cytosolic phospholipase A2alpha (cPLA2alpha, type IVA phospholipase) are described. Inhibitors of cPLA2alpha are predicted to be efficacious in treating asthma as well as the signs and symptoms of osteoarthritis, rheumatoid arthritis, and pain. The introduction of a benzyl sulfonamide substituent at C2 was found to impart improved potency of these inhibitors, and the SAR of these sulfonamide analogues is disclosed. Compound 123 (Ecopladib) is a sub-micromolar inhibitor of cPLA2alpha in the GLU micelle and rat whole blood assays. Compound 123 displayed oral efficacy in the rat carrageenan air pouch and rat carrageenan-induced paw edema models.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Bou, G.; Santillana, E; Sheri, A
Class D {beta}-lactamases represent a growing and diverse class of penicillin-inactivating enzymes that are usually resistant to commercial {beta}-lactamase inhibitors. As many such enzymes are found in multi-drug resistant (MDR) Acinetobacter baumannii and Pseudomonas aeruginosa, novel {beta}-lactamase inhibitors are urgently needed. Five unique 6-alkylidene-2{prime}-substituted penicillanic acid sulfones (1-5) were synthesized and tested against OXA-24, a clinically important {beta}-lactamase that inactivates carbapenems and is found in A. baumannii. Based upon the roles Tyr112 and Met223 play in the OXA-24 {beta}-lactamase, we also engineered two variants (Tyr112Ala and Tyr112Ala,Met223Ala) to test the hypothesis that the hydrophobic tunnel formed by these residues influencesmore » inhibitor recognition. IC{sub 50} values against OXA-24 and two OXA-24 {beta}-lactamase variants ranged from 10 {+-} 1 (4 vs WT) to 338 {+-} 20 nM (5 vs Tyr112Ala, Met223Ala). Compound 4 possessed the lowest K{sub i} (500 {+-} 80 nM vs WT), and 1 possessed the highest inactivation efficiency (k{sub inact}/K{sub i} = 0.21 {+-} 0.02 {micro}M{sup -1}s{sup -1}). Electrospray ionization mass spectrometry revealed a single covalent adduct, suggesting the formation of an acyl-enzyme intermediate. X-ray structures of OXA-24 complexed to four inhibitors (2.0-2.6 {angstrom}) reveal the formation of stable bicyclic aromatic intermediates with their carbonyl oxygen in the oxyanion hole. These data provide the first structural evidence that 6-alkylidene-2{prime}-substituted penicillin sulfones are effective mechanism-based inactivators of class D {beta}-lactamases. Their unique chemistry makes them developmental candidates. Mechanisms for class D hydrolysis and inhibition are discussed, and a pathway for the evolution of the BlaR1 sensor of Staphylococcus aureus to the class D {beta}-lactamases is proposed.« less
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Activity-dependent rapid local RhoA synthesis is required for hippocampal synaptic plasticity.
Briz, Victor; Zhu, Guoqi; Wang, Yubin; Liu, Yan; Avetisyan, Mariam; Bi, Xiaoning; Baudry, Michel
2015-02-04
Dendritic protein synthesis and actin cytoskeleton reorganization are important events required for the consolidation of hippocampal LTP and memory. However, the temporal and spatial relationships between these two processes remain unclear. Here, we report that treatment of adult rat hippocampal slices with BDNF or with tetraethylammonium (TEA), which induces a chemical form of LTP, produces a rapid and transient increase in RhoA protein levels. Changes in RhoA were restricted to dendritic spines of CA3 and CA1 and require de novo protein synthesis regulated by mammalian target of rapamycin (mTOR). BDNF-mediated stimulation of RhoA activity, cofilin phosphorylation, and actin polymerization were completely suppressed by protein synthesis inhibitors. Furthermore, intrahippocampal injections of RhoA antisense oligodeoxynucleotides inhibited theta burst stimulation (TBS)-induced RhoA upregulation in dendritic spines and prevented LTP consolidation. Addition of calpain inhibitors after BDNF or TEA treatment maintained RhoA levels elevated and prolonged the effects of BDNF and TEA on actin polymerization. Finally, the use of isoform-selective calpain inhibitors revealed that calpain-2 was involved in RhoA synthesis, whereas calpain-1 mediated RhoA degradation. Overall, this mechanism provides a novel link between dendritic protein synthesis and reorganization of the actin cytoskeleton in hippocampal dendritic spines during LTP consolidation. Copyright © 2015 the authors 0270-6474/15/352269-14$15.00/0.
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Hydrophobic amino acids as a new class of kinetic inhibitors for gas hydrate formation
Sa, Jeong-Hoon; Kwak, Gye-Hoon; Lee, Bo Ram; Park, Da-Hye; Han, Kunwoo; Lee, Kun-Hong
2013-01-01
As the foundation of energy industry moves towards gas, flow assurance technology preventing pipelines from hydrate blockages becomes increasingly significant. However, the principle of hydrate inhibition is still poorly understood. Here, we examined natural hydrophobic amino acids as novel kinetic hydrate inhibitors (KHIs), and investigated hydrate inhibition phenomena by using them as a model system. Amino acids with lower hydrophobicity were found to be better KHIs to delay nucleation and retard growth, working by disrupting the water hydrogen bond network, while those with higher hydrophobicity strengthened the local water structure. It was found that perturbation of the water structure around KHIs plays a critical role in hydrate inhibition. This suggestion of a new class of KHIs will aid development of KHIs with enhanced biodegradability, and the present findings will accelerate the improved control of hydrate formation for natural gas exploitation and the utilization of hydrates as next-generation gas capture media. PMID:23938301
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Margolis, Henry C.; Kwak, Seo-Young; Yamazaki, Hajime
2014-01-01
Vertebrate mineralized tissues, i.e., enamel, dentin, cementum, and bone, have unique hierarchical structures and chemical compositions. Although these tissues are similarly comprised of a crystalline calcium apatite mineral phase and a protein component, they differ with respect to crystal size and shape, level and distribution of trace mineral ions, the nature of the proteins present, and their relative proportions of mineral and protein components. Despite apparent differences, mineralized tissues are similarly derived by highly concerted extracellular processes involving matrix proteins, proteases, and mineral ion fluxes that collectively regulate the nucleation, growth and organization of forming mineral crystals. Nature, however, provides multiple ways to control the onset, rate, location, and organization of mineral deposits in developing mineralized tissues. Although our knowledge is quite limited in some of these areas, recent evidence suggests that hard tissue formation is, in part, controlled through the regulation of specific molecules that inhibit the mineralization process. This paper addresses the role of mineralization inhibitors in the regulation of biological mineralization with emphasis on the relevance of current findings to the process of amelogenesis. Mineralization inhibitors can also serve to maintain driving forces for calcium phosphate precipitation and prevent unwanted mineralization. Recent evidence shows that native phosphorylated amelogenins have the capacity to prevent mineralization through the stabilization of an amorphous calcium phosphate precursor phase, as observed in vitro and in developing teeth. Based on present findings, the authors propose that the transformation of initially formed amorphous mineral deposits to enamel crystals is an active process associated with the enzymatic processing of amelogenins. Such processing may serve to control both initial enamel crystal formation and subsequent maturation. PMID:25309443
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Ormerod, J G; Nesbakken, T; Beale, S I
1990-01-01
The green sulfur bacterium Chlorobium vibrioforme contains two types of bacteriochlorophyll (Bchl). The minor pigment, Bchl a, is associated primarily with the cell membrane and its reaction centers; and the major light-harvesting antenna pigment, Bchl d, is found primarily in the chlorosomes, which are attached to the inner surface of the cell membrane. Anesthetic gases, such as N2O, ethylene, and acetylene, were found to inhibit the synthesis of Bchl d, but not of Bchl a, thus allowing the cells to grow at high light intensities with a greatly diminished content of antenna pigment. Chlorosomes were absent or sparse in inhibited cells. Porphyrins accumulated in the inhibited cells. The major one was identified as the Bchl precursor magnesium-protoporphyrin IX monomethyl ester (Mg-PPME) by comparative absorption and fluorescence spectroscopy and thin-layer chromatography of the porphyrin and its derivatives with those of authentic protoporphyrin IX. Small amounts of Mg-PPME were present in control cells, but the addition of inhibitor caused a rapid increase in the Mg-PPME concentration, accompanying the inhibition of Bchl d synthesis. Cells grown in the presence of ethephon (as a source of ethylene) and allowed to stand in dim light for long periods accumulated large amounts of PPME and other porphyrins and excreted or released porphyrins, which accumulated as a brown precipitate in the culture. Inhibition of Bchl d synthesis was relieved upon removal of the inhibitor. These results suggest that the gases act at a step in pigment biosynthesis that affects the utilization of Mg-PPME for isocyclic ring formation. Synthesis of Bchl d and Bchl a may be differentially affected by the gases because of compartmentation of their biosynthetic apparatus or because competition for precursors favors Bchl a synthesis. An ethephon-resistant mutant strain was isolated by selection for growth in dim, long-wavelength light. The mutant cells were also resistant to acetylene, but not
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Qian,J.; Cuerrier, D.; Davies, P.
Calpains are intracellular cysteine proteases that catalyze the cleavage of target proteins in response to Ca2+ signaling. When Ca2+ homeostasis is disrupted, calpain overactivation causes unregulated proteolysis, which can contribute to diseases such as postischemic injury and cataract formation. Potent calpain inhibitors exist, but of these many cross-react with other cysteine proteases and will need modification to specifically target calpain. Here, we present crystal structures of rat calpain 1 protease core ({mu}I-II) bound to two a-ketoamide-based calpain inhibitors containing adenyl and piperazyl primed-side extensions. An unexpected aromatic-stacking interaction is observed between the primed-side adenine moiety and the Trp298 side chain.more » This interaction increased the potency of the inhibitor toward {mu}I-II and heterodimeric m-calpain. Moreover, stacking orients the adenine such that it can be used as a scaffold for designing novel primed-side address regions, which could be incorporated into future inhibitors to enhance their calpain specificity.« less
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Chemoproteomics-Aided Medicinal Chemistry for the Discovery of EPHA2 Inhibitors.
Heinzlmeir, Stephanie; Lohse, Jonas; Treiber, Tobias; Kudlinzki, Denis; Linhard, Verena; Gande, Santosh Lakshmi; Sreeramulu, Sridhar; Saxena, Krishna; Liu, Xiaofeng; Wilhelm, Mathias; Schwalbe, Harald; Kuster, Bernhard; Médard, Guillaume
2017-06-21
The receptor tyrosine kinase EPHA2 has gained attention as a therapeutic drug target for cancer and infectious diseases. However, EPHA2 research and EPHA2-based therapies have been hampered by the lack of selective small-molecule inhibitors. Herein we report the synthesis and evaluation of dedicated EPHA2 inhibitors based on the clinical BCR-ABL/SRC inhibitor dasatinib as a lead structure. We designed hybrid structures of dasatinib and the previously known EPHA2 binders CHEMBL249097, PD-173955, and a known EPHB4 inhibitor in order to exploit both the ATP pocket entrance as well as the ribose pocket as binding epitopes in the kinase EPHA2. Medicinal chemistry and inhibitor design were guided by a chemical proteomics approach, allowing early selectivity profiling of the newly synthesized inhibitor candidates. Concomitant protein crystallography of 17 inhibitor co-crystals delivered detailed insight into the atomic interactions that underlie the structure-affinity relationship. Finally, the anti-proliferative effect of the inhibitor candidates was confirmed in the glioblastoma cell line SF-268. In this work, we thus discovered a novel EPHA2 inhibitor candidate that features an improved selectivity profile while maintaining potency against EPHA2 and anticancer activity in SF-268 cells. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Recent developments in the synthesis of acetylcholinesterase inhibitors.
Marco, José L; Carreiras, M Carmo
2003-09-01
The acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activities of a series of pyrano[2,3-b]quinolines (2, 3), [1,8]naphthyridines (5, 6), 4-amino-2,3-diaryl-5,6,7,8-tetrahydrofuro[2,3-b]quinolines (11-13)/ 4-amino-6,7,8,9-tetrahydro-2,3-diphenyl-5H-cyclohepta[e]furo[2,3-b]pyridine (14), 4-amino-5,6,7,8-tetrahydro-2,3-diphenylthieno[2,3-b]quinoline (15)/ 4-amino-6,7,8,9-tetrahydro-2,3-diphenyl-5H-cyclohepta[e]thieno[2,3-b]pyridine (16) are described. These compounds are tacrine analogues that have been prepared from readily available polyfunctionalized ethyl [6-amino-5-cyano-4H-pyran]-3-carboxylates (9, 10), ethyl [6-amino-5-cyanopyridine]-3-carboxylates (7, 8), 2-amino-3-cyano-4,5-diarylfurans (17-19) and 2-amino-3-cyano-4,5-diphenylthiophene (20) via Friedländer condensation with selected ketones. These compounds are competitive and, in a few cases, non-competitive inhibitors for AChE, the most potent being compound (14), though three-fold less active than tacrine. The BuChE inhibitory activity is only significant in compounds 11 and 14, ten-fold less active than tacrine. Furthermore, the products 12 and 13 are selective and moderate AChE inhibitors.
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Emanuelsson, H; Heby, O
1978-01-01
Development eggs of the polychete Ophryotrocha labronica were analyzed for polyamines during the first 6 days after fertilization. The spermine content dominated initially, but gradually decreased. It was surpassed by putrescine, which rapidly increased to a maximum on the 3rd day, i.e., at the inception of grastrulation. The spermidine content was low during the entire period. Treatment of eggs with the putrescine synthesis inhibitor alpha-methylornithine from the onset of development led to developmental arrest at gastrulation and to an abnormally low content of putrescine in the treated embryos. Methylglyoxal bis(guanylhydrazone), an inhibitor of spermine and spermidine synthesis, had no visible effect of development. Our observations strongly suggest that putrescine synthesis is indispensable in early embryonic development of Ophryotrocha. Images PMID:273215
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Tabackman, Alexa A.; Frankson, Rochelle; Marsan, Eric S.
Histone deacetylases (HDACs) catalyze the hydrolysis of acetylated lysine side chains in histone and non-histone proteins, and play a critical role in the regulation of many biological processes, including cell differentiation, proliferation, senescence, and apoptosis. Aberrant HDAC activity is associated with cancer, making these enzymes important targets for drug design. In general, HDAC inhibitors (HDACi) block the proliferation of tumor cells by inducing cell differentiation, cell cycle arrest, and/or apoptosis, and comprise some of the leading therapies in cancer treatments. To date, four HDACi have been FDA approved for the treatment of cancers: suberoylanilide hydroxamic acid (SAHA, Vorinostat, Zolinza®), romidepsinmore » (FK228, Istodax®), belinostat (Beleodaq®), and panobinostat (Farydak®). Most current inhibitors are pan-HDACi, and non-selectively target a number of HDAC isoforms. Six previously reported HDACi were rationally designed, however, to target a unique sub-pocket found only in HDAC8. While these inhibitors were indeed potent against HDAC8, and even demonstrated specificity for HDAC8 over HDACs 1 and 6, there were no structural data to confirm the mode of binding. Here we report the X-ray crystal structure of Compound 6 complexed with HDAC8 to 1.98 Å resolution. We also describe the use of molecular docking studies to explore the binding interactions of the other 5 related HDACi. Our studies confirm that the HDACi induce the formation of and bind in the HDAC8-specific subpocket, offering insights into isoform-specific inhibition.« less
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Göring, Stefan; Bensinger, Dennis; Naumann, Eva C; Schmidt, Boris
2015-03-01
Activating mutations of FMS-like tyrosine kinase 3 (FLT3) are present in ∼30 % of patients with acute myeloid leukemia (AML) and are associated with poor prognosis. Point mutations in the tyrosine kinase domain (TKD) are observed as primary mutations or are acquired as secondary mutations in FLT3 with internal tandem duplications (ITDs) after treatment with tyrosine kinase inhibitors (TKIs). Although dozens of potent inhibitors against FLT3 ITD have been reported, activating TKD point mutations, especially at residues F691 and D835, remain the leading cause for therapy resistance, highlighting the consistent need for new potent inhibitors. Herein we report the identification and characterization of novel quinoxaline-based FLT3 inhibitors. We used the pharmacophore features of diverse known inhibitors as a starting point for a new optimization algorithm for type II TKIs, starting from an in silico library pharmacophore search and induced-fit docking in the known FLT3 structure. This led to the design of a set of diverse quinoxalinebisarylureas, which were profiled in an FLT3 kinase activity assay. The most promising compounds were further evaluated in a zebrafish embryo phenotype assay. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Torron, Susana; Semlitsch, Stefan; Martinelle, Mats; Johansson, Mats
2016-12-12
The work herein presented describes the synthesis and polymerization of series of bio-based epoxy resins prepared through lipase catalyzed transesterification. The epoxy-functional polyester resins with various architectures (linear, tri-branched, and tetra-branched) were synthesized through condensation of fatty acids derived from epoxidized soybean oil and linseed oil with three different hydroxyl cores under bulk conditions. The selectivity of the lipases toward esterification/transesterification reactions allowed the formation of macromers with up to 12 epoxides in the backbone. The high degree of functionality of the resins resulted in polymer thermosets with T g values ranging from -25 to over 100 °C prepared through cationic polymerization. The determining parameters of the synthesis and the mechanism for the formation of the species were determined through kinetic studies by 1 H NMR, SEC, and molecular modeling studies. The correlation between macromer structure and thermoset properties was studied through real-time FTIR measurements, DSC, and DMA.
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Shi, Yuguang; Cheng, Dong
2009-07-01
Monoacyglycerol acyltransferases (MGATs) and diacylglycerol acyltransferases (DGATs) catalyze two consecutive steps of enzyme reactions in the synthesis of triacylglycerols (TAGs). The metabolic complexity of TAG synthesis is reflected by the presence of multiple isoforms of MGAT and DGAT enzymes that differ in catalytic properties, subcellular localization, tissue distribution, and physiological functions. MGAT and DGAT enzymes play fundamental roles in the metabolism of monoacylglycerol (MAG), diacylglycerol (DAG), and triacylglycerol (TAG) that are involved in many aspects of physiological functions, such as intestinal fat absorption, lipoprotein assembly, adipose tissue formation, signal transduction, satiety, and lactation. The recent progress in the phenotypic characterization of mice deficient in MGAT and DGAT enzymes and the development of chemical inhibitors have revealed important roles of these enzymes in the regulation of energy homeostasis and insulin sensitivity. Consequently, selective inhibition of MGAT or DGAT enzymes by synthetic compounds may provide novel treatment for obesity and its related metabolic complications.
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Shi, Yuguang; Cheng, Dong
2009-01-01
Monoacyglycerol acyltransferases (MGATs) and diacylglycerol acyltransferases (DGATs) catalyze two consecutive steps of enzyme reactions in the synthesis of triacylglycerols (TAGs). The metabolic complexity of TAG synthesis is reflected by the presence of multiple isoforms of MGAT and DGAT enzymes that differ in catalytic properties, subcellular localization, tissue distribution, and physiological functions. MGAT and DGAT enzymes play fundamental roles in the metabolism of monoacylglycerol (MAG), diacylglycerol (DAG), and triacylglycerol (TAG) that are involved in many aspects of physiological functions, such as intestinal fat absorption, lipoprotein assembly, adipose tissue formation, signal transduction, satiety, and lactation. The recent progress in the phenotypic characterization of mice deficient in MGAT and DGAT enzymes and the development of chemical inhibitors have revealed important roles of these enzymes in the regulation of energy homeostasis and insulin sensitivity. Consequently, selective inhibition of MGAT or DGAT enzymes by synthetic compounds may provide novel treatment for obesity and its related metabolic complications. PMID:19116371
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Social Recognition Memory Requires Two Stages of Protein Synthesis in Mice
ERIC Educational Resources Information Center
Wolf, Gerald; Engelmann, Mario; Richter, Karin
2005-01-01
Olfactory recognition memory was tested in adult male mice using a social discrimination task. The testing was conducted to begin to characterize the role of protein synthesis and the specific brain regions associated with activity in this task. Long-term olfactory recognition memory was blocked when the protein synthesis inhibitor anisomycin was…
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2015-01-01
Recently, a feedback inhibition of the chloroplastic 1-deoxy-d-xylulose 5-phosphate (DXP)/2-C-methyl-d-erythritol 4-phosphate (MEP) pathway of isoprenoid synthesis by end products dimethylallyl diphosphate (DMADP) and isopentenyl diphosphate (IDP) was postulated, but the extent to which DMADP and IDP can build up is not known. We used bisphosphonate inhibitors, alendronate and zoledronate, that inhibit the consumption of DMADP and IDP by prenyltransferases to gain insight into the extent of end product accumulation and possible feedback inhibition in isoprene-emitting hybrid aspen (Populus tremula × Populus tremuloides). A kinetic method based on dark release of isoprene emission at the expense of substrate pools accumulated in light was used to estimate the in vivo pool sizes of DMADP and upstream metabolites. Feeding with fosmidomycin, an inhibitor of DXP reductoisomerase, alone or in combination with bisphosphonates was used to inhibit carbon input into DXP/MEP pathway or both input and output. We observed a major increase in pathway intermediates, 3- to 4-fold, upstream of DMADP in bisphosphonate-inhibited leaves, but the DMADP pool was enhanced much less, 1.3- to 1.5-fold. In combined fosmidomycin/bisphosphonate treatment, pathway intermediates accumulated, reflecting cytosolic flux of intermediates that can be important under strong metabolic pull in physiological conditions. The data suggested that metabolites accumulated upstream of DMADP consist of phosphorylated intermediates and IDP. Slow conversion of the huge pools of intermediates to DMADP was limited by reductive energy supply. These data indicate that the DXP/MEP pathway is extremely elastic, and the presence of a significant pool of phosphorylated intermediates provides an important valve for fine tuning the pathway flux. PMID:25926480
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Sail, Vibhavari; Rizzo, Alessandro A; Chatterjee, Nimrat; Dash, Radha C; Ozen, Zuleyha; Walker, Graham C; Korzhnev, Dmitry M; Hadden, M Kyle
2017-07-21
Translesion synthesis (TLS) is an important mechanism through which proliferating cells tolerate DNA damage during replication. The mutagenic Rev1/Polζ-dependent branch of TLS helps cancer cells survive first-line genotoxic chemotherapy and introduces mutations that can contribute to the acquired resistance so often observed with standard anticancer regimens. As such, inhibition of Rev1/Polζ-dependent TLS has recently emerged as a strategy to enhance the efficacy of first-line chemotherapy and reduce the acquisition of chemoresistance by decreasing tumor mutation rate. The TLS DNA polymerase Rev1 serves as an integral scaffolding protein that mediates the assembly of the active multiprotein TLS complexes. Protein-protein interactions (PPIs) between the C-terminal domain of Rev1 (Rev1-CT) and the Rev1-interacting region (RIR) of other TLS DNA polymerases play an essential role in regulating TLS activity. To probe whether disrupting the Rev1-CT/RIR PPI is a valid approach for developing a new class of targeted anticancer agents, we designed a fluorescence polarization-based assay that was utilized in a pilot screen for small molecule inhibitors of this PPI. Two small molecule scaffolds that disrupt this interaction were identified, and secondary validation assays confirmed that compound 5 binds to Rev1-CT at the RIR interface. Finally, survival and mutagenesis assays in mouse embryonic fibroblasts and human fibrosarcoma HT1080 cells treated with cisplatin and ultraviolet light indicate that these compounds inhibit mutagenic Rev1/Polζ-dependent TLS in cells, validating the Rev1-CT/RIR PPI for future anticancer drug discovery and identifying the first small molecule inhibitors of TLS that target Rev1-CT.
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Cyclooxygenase (COX) inhibition is of concern in fish because COX inhibitors (e.g., ibuprofen) are ubiquitous in aquatic systems/fish tissues, and can disrupt synthesis of prostaglandins that modulate a variety of essential biological functions (e.g., reproduction). This study ut...
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Synthesis of sphingosine is essential for oxidative stress-induced apoptosis of photoreceptors.
Abrahan, Carolina E; Miranda, Gisela E; Agnolazza, Daniela L; Politi, Luis E; Rotstein, Nora P
2010-02-01
Oxidative stress is involved in inducing apoptosis of photoreceptors in many retinal neurodegenerative diseases. It has been shown that oxidative stress increases in photoreceptors the synthesis of ceramide, a sphingolipid precursor that then activates apoptosis. In several cell types, ceramide is converted by ceramidases to sphingosine (Sph), another apoptosis mediator; hence, this study was undertaken to determine whether Sph participates in triggering photoreceptor apoptosis. Rat retina neurons were incubated with [(3)H]palmitic acid and treated with the oxidant paraquat (PQ) to evaluate Sph synthesis. Sph was added to cultures with or without docosahexaenoic acid (DHA), the major retina polyunsaturated fatty acid and a photoreceptor survival factor, to evaluate apoptosis. Synthesis of Sph and sphingosine-1-phosphate (S1P), a prosurvival signal, were inhibited with alkaline ceramidase or sphingosine kinase inhibitors, respectively, before adding PQ, C(2)-ceramide, or Sph. Apoptosis, mitochondrial membrane polarization, cytochrome c localization, and reactive oxygen species (ROS) production were determined. PQ increased [(3)H]Sph synthesis in photoreceptors and blocking this synthesis by inhibiting alkaline ceramidase decreased PQ-induced apoptosis. Addition of Sph induced photoreceptor apoptosis, increased ROS production, and promoted cytochrome c release from mitochondria. Although DHA prevented this apoptosis, inhibiting Sph conversion to S1P blocked DHA protection. These results suggest that oxidative stress enhances formation of ceramide and its subsequent breakdown to Sph; ceramide and/or Sph would then trigger photoreceptor apoptosis. Preventing Sph synthesis or promoting its phosphorylation to S1P rescued photoreceptors, suggesting that Sph is a mediator of their apoptosis and modulation of Sph metabolism may be crucial for promoting photoreceptor survival.
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Effectively delivering a unique hsp90 inhibitor using star polymers.
Kim, Seong Jong; Ramsey, Deborah M; Boyer, Cyrille; Davis, Thomas P; McAlpine, Shelli R
2013-07-25
We report the synthesis of a novel heat shock protein 90 (hsp90) inhibitor conjugated to a star polymer. Using reversible addition-fragmentation chain-transfer (RAFT) polymerization, we prepared star polymers comprised of PEG attached to a predesigned functional core. The stars were cross-linked using disulfide linkers, and a tagged version of our hsp90 inhibitor was conjugated to the polymer core to generate nanoparticles (14 nM). Dynamic light scattering showed that the nanoparticles were stable in cell growth media for 5 days, and HPLC analysis of compound-release at 3 different pH values showed that release was pH dependent. Cell cytotoxicity studies and confocal microscopy verify that our hsp90 inhibitor was delivered to cells using this nanoparticle delivery system. Further, delivery of our hsp90 inhibitor using star polymer induces apoptosis by a caspase 3-dependent pathway. These studies show that we can deliver our hsp90 inhibitor effectively using star polymers, and induce apoptosis by the same pathway as the parent compound.
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Fontoura, Nathalia Giglio; Bellinato, Diogo Fernandes; Valle, Denise; Lima, José Bento Pereira
2012-05-01
The mosquito Aedes aegypti is the main focus of dengue control campaigns. Because of widespread resistance against conventional chemical insecticides, chitin synthesis inhibitors (CSIs) are considered control alternatives. We evaluated the resistance status of four Brazilian Ae. aegypti populations to both the organophosphate temephos and the pyrethroid deltamethrin, which are used in Brazil to control larvae and adults, respectively. All vector populations exhibited high levels of temephos resistance and varying rates of alterations in their susceptibility to pyrethroids. The effect of the CSI novaluron on these populations was also investigated. Novaluron was effective against all populations under laboratory conditions. Field-simulated assays with partial water replacement were conducted to evaluate novaluron persistence. Bioassays were continued until an adult emergence inhibition of at least 70% was attained. We found a residual effect of eight weeks under indoor conditions and novaluron persisted for five-six weeks in assays conducted in an external area. Our data show that novaluron is effective against the Ae. aegypti populations tested, regardless of their resistance to conventional chemical insecticides.
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Lindenmayer, Aristid; Schoen, Howard F.
1967-01-01
The initiation of perithecia in the homothallic ascomycete Sordaria fimicola was completely suppressed, without seriously inhibiting vegetative growth, by growing the fungus on an agar medium containing one of the following additions: 1) 1 μm 5-fluorouracil, 2) 10 to 100 μm 6-azauracil, 8-azaguanine or 8-azaadenine, 3) 50 to 500 μm cyanide or azide, 4) 5% (w/v) casein hydrolysate. In contrast to the selective activity of the analogues of 3 RNA bases, whose inhibition could be reversed by the appropriate normal bases only, none of the analogues of thymine were active, neither were the thio-derivatives of RNA bases. Other inhibitors of RNA and protein synthesis, like actinomycin D, puromycin and cycloheximide, were also without selective activity, although the last of these inhibited perithecial maturation at 0.1 μm concentration but not initiation. Amino acid analogues were inactive, as were the metabolic inhibitors thiourea, 2,4-dinitrophenol and fluoride. The compounds which inhibited the formation of perithecia also lowered the branching frequency of leading hyphae, but not their linear growth rates. Consequently, the branch densities were diminished in their presence. Hypotheses to account for these findings are discussed in terms of inhibition of growth in general, of the synthesis of some specific messenger RNAs, and of RNA-mediated transport across membranes, the last of which seeming the most fruitful for further work. PMID:16656614
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Insect P450 inhibitors and insecticides: challenges and opportunities.
Feyereisen, René
2015-06-01
P450 enzymes are encoded by a large number of genes in insects, often over a hundred. They play important roles in insecticide metabolism and resistance, and growing numbers of P450 enzymes are now known to catalyse important physiological reactions, such as hormone metabolism or cuticular hydrocarbon synthesis. Ways to inhibit P450 enzymes specifically or less specifically are well understood, as P450 inhibitors are found as drugs, as fungicides, as plant growth regulators and as insecticide synergists. Yet there are no P450 inhibitors as insecticides on the market. As new modes of action are constantly needed to support insecticide resistance management, P450 inhibitors should be considered because of their high potential for insect selectivity, their well-known mechanisms of action and the increasing ease of rational design and testing. © 2014 Society of Chemical Industry.
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Walker, Louise A.; Lee, Keunsook K.; Munro, Carol A.
2015-01-01
Treatment of Aspergillus fumigatus with echinocandins such as caspofungin inhibits the synthesis of cell wall β-1,3-glucan, which triggers a compensatory stimulation of chitin synthesis. Activation of chitin synthesis can occur in response to sub-MICs of caspofungin and to CaCl2 and calcofluor white (CFW), agonists of the protein kinase C (PKC), and Ca2+-calcineurin signaling pathways. A. fumigatus mutants with the chs gene (encoding chitin synthase) deleted (ΔAfchs) were tested for their response to these agonists to determine the chitin synthase enzymes that were required for the compensatory upregulation of chitin synthesis. Only the ΔAfchsG mutant was hypersensitive to caspofungin, and all other ΔAfchs mutants tested remained capable of increasing their chitin content in response to treatment with CaCl2 and CFW and caspofungin. The resulting increase in cell wall chitin content correlated with reduced susceptibility to caspofungin in the wild type and all ΔAfchs mutants tested, with the exception of the ΔAfchsG mutant, which remained sensitive to caspofungin. In vitro exposure to the chitin synthase inhibitor, nikkomycin Z, along with caspofungin demonstrated synergistic efficacy that was again AfChsG dependent. Dynamic imaging using microfluidic perfusion chambers demonstrated that treatment with sub-MIC caspofungin resulted initially in hyphal tip lysis. However, thickened hyphae emerged that formed aberrant microcolonies in the continued presence of caspofungin. In addition, intrahyphal hyphae were formed in response to echinocandin treatment. These in vitro data demonstrate that A. fumigatus has the potential to survive echinocandin treatment in vivo by AfChsG-dependent upregulation of chitin synthesis. Chitin-rich cells may, therefore, persist in human tissues and act as the focus for breakthrough infections. PMID:26169407
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Hung, Hui-Chi; Hsiao, Ya-Hsin
2015-01-01
Background: It is known that neurogenesis occurs throughout the life mostly in the subgranular zone of the hippocampus and the subventricular zone of the lateral ventricle. We investigated whether neurogenesis occurred in the amygdala and its function in fear memory formation. Methods: For detection of newborn neurons, mice were injected intraperitoneally with 5-bromo-2’-deoxyuridine (BrdU) 2h before receiving 15 tone–footshock pairings, and newborn neurons were analyzed 14 and 42 days after training. To determine the relationship between neurogenesis and memory formation, mice were given a proliferation inhibitor methylazoxymethanol (MAM) or a DNA synthesis inhibitor cytosine arabinoside (Ara-C). To test whether sonic hedgehog (Shh) signaling was required for neurogenesis, Shh-small hairpin–interfering RNA (shRNA) was inserted into a retroviral vector (Retro-Shh-shRNA). Results: The number of BrdU+/Neuronal nuclei (NeuN)+ cells was significantly higher in the conditioned mice, suggesting that association of tone with footshock induced neurogenesis. MAM and Ara-C markedly reduced neurogenesis and impaired fear memory formation. Shh, its receptor patched 1 (Ptc1), and transcription factor Gli1 protein levels increased at 1 day and returned to baseline at 7 days after fear conditioning. Retro-Shh-shRNA, which knocked down Shh specifically in the mitotic neurons, reduced the number of BrdU+/NeuN+ cells and decreased freezing responses. Conclusions: These results suggest that fear learning induces Shh signaling activation in the amygdala, which promotes neurogenesis and fear memory formation. PMID:25522410
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Khrimian, Ashot; Lance, David R; Mastro, Victor C; Elkinton, Joseph S
2010-02-10
The winter moth, Operophtera brumata (Lepidoptera: Geometridae), is an early-season defoliator that attacks a wide variety of hardwoods and, in some cases, conifers. The insect is native to Europe but has become established in at least three areas of North America including southeastern New England. The female-produced sex attractant pheromone of the winter moth was identified as (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene (1), which also attracts a native congener, the Bruce spanworm, Operophtera bruceata . Dissection, or (for certainty) DNA molecular testing, is required to differentiate between males of the two species. Thus, a trapping method that is selective for winter moth would be desirable. A geometric isomer of the pheromone, (3E,6Z,9Z)-1,3,6,9-nonadecatetraene (2), can reportedly inhibit attraction of Bruce spanworm to traps without affecting winter moth catch, but use of the pheromone and inhibitor together has not been optimized, nor has the synthesis of the inhibitor. This paper presents two new syntheses of the inhibitor (3E,6Z,9Z)-1,3,6,9-nonadecatetraene based on the intermediate (3Z,6Z)-3,6-hexadecadien-1-ol (4), which has also been utilized in the synthesis of the pheromone. The syntheses combine traditional acetylenic chemistry and Wittig olefination reactions. In one approach, 2 was synthesized in 80% purity (20% being pheromone 1), and in the second, tetraene 2 of 96% purity (and free of 1) was produced in 25% overall yield from dienol 4. The last method benefitted from a refined TEMPO-mediated PhI(OAc)(2) oxidation of 4 and a two-carbon homologation of the corresponding aldehyde 7.
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Two-dimensional infrared spectroscopy reveals the complex behaviour of an amyloid fibril inhibitor
NASA Astrophysics Data System (ADS)
Middleton, Chris T.; Marek, Peter; Cao, Ping; Chiu, Chi-Cheng; Singh, Sadanand; Woys, Ann Marie; de Pablo, Juan J.; Raleigh, Daniel P.; Zanni, Martin T.
2012-05-01
Amyloid formation has been implicated in the pathology of over 20 human diseases, but the rational design of amyloid inhibitors is hampered by a lack of structural information about amyloid-inhibitor complexes. We use isotope labelling and two-dimensional infrared spectroscopy to obtain a residue-specific structure for the complex of human amylin (the peptide responsible for islet amyloid formation in type 2 diabetes) with a known inhibitor (rat amylin). Based on its sequence, rat amylin should block formation of the C-terminal β-sheet, but at 8 h after mixing, rat amylin blocks the N-terminal β-sheet instead. At 24 h after mixing, rat amylin blocks neither β-sheet and forms its own β-sheet, most probably on the outside of the human fibrils. This is striking, because rat amylin is natively disordered and not previously known to form amyloid β-sheets. The results show that even seemingly intuitive inhibitors may function by unforeseen and complex structural processes.
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N-acetylcysteine stimulates protein synthesis in enterocytes independently of glutathione synthesis.
Yi, Dan; Hou, Yongqing; Wang, Lei; Long, Minhui; Hu, Shengdi; Mei, Huimin; Yan, Liqiong; Hu, Chien-An Andy; Wu, Guoyao
2016-02-01
Dietary supplementation with N-acetylcysteine (NAC) has been reported to improve intestinal health and treat gastrointestinal diseases. However, the underlying mechanisms are not fully understood. According to previous reports, NAC was thought to exert its effect through glutathione synthesis. This study tested the hypothesis that NAC enhances enterocyte growth and protein synthesis independently of cellular glutathione synthesis. Intestinal porcine epithelial cells were cultured for 3 days in Dulbecco's modified Eagle medium containing 0 or 100 μM NAC. To determine a possible role for GSH (the reduced form of glutathione) in mediating the effect of NAC on cell growth and protein synthesis, additional experiments were conducted using culture medium containing 100 μM GSH, 100 μM GSH ethyl ester (GSHee), diethylmaleate (a GSH-depletion agent; 10 μM), or a GSH-synthesis inhibitor (buthionine sulfoximine, BSO; 20 μM). NAC increased cell proliferation, GSH concentration, and protein synthesis, while inhibiting proteolysis. GSHee enhanced cell proliferation and GSH concentration without affecting protein synthesis but inhibited proteolysis. Conversely, BSO or diethylmaleate reduced cell proliferation and GSH concentration without affecting protein synthesis, while promoting protein degradation. At the signaling level, NAC augmented the protein abundance of total mTOR, phosphorylated mTOR, and phosphorylated 70S6 kinase as well as mRNA levels for mTOR and p70S6 kinase in IPEC-1 cells. Collectively, these results indicate that NAC upregulates expression of mTOR signaling proteins to stimulate protein synthesis in enterocytes independently of GSH generation. Our findings provide a hitherto unrecognized biochemical mechanism for beneficial effects of NAC in intestinal cells.
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Chung, Christine C; Ohwaki, Kenji; Schneeweis, Jonathan E; Stec, Erica; Varnerin, Jeffrey P; Goudreau, Paul N; Chang, Amy; Cassaday, Jason; Yang, Lihu; Yamakawa, Takeru; Kornienko, Oleg; Hodder, Peter; Inglese, James; Ferrer, Marc; Strulovici, Berta; Kusunoki, Jun; Tota, Michael R; Takagi, Toshimitsu
2008-06-01
Here we report the development and miniaturization of a cell-free enzyme assay for ultra-high-throughput screening (uHTS) for inhibitors of two potential drug targets for obesity and cancer: fatty acid synthase (FAS) and acetyl-coenzyme A (CoA) carboxylase (ACC) 2. This assay detects CoA, a product of the FAS-catalyzed condensation of malonyl-CoA and acetyl-CoA. The free thiol of CoA can react with 7-diethylamino-3-(4'-maleimidylphenyl)-4-methylcoumarin (CPM), a profluorescent coumarin maleimide derivative that becomes fluorescent upon reaction with thiols. FAS produces long-chain fatty acid and CoA from the condensation of malonyl-CoA and acetyl-CoA. In our FAS assay, CoA released in the FAS reaction forms a fluorescence adduct with CPM that emits at 530 nm when excited at 405 nm. Using this detection method for CoA, we measured the activity of sequential enzymes in the fatty acid synthesis pathway to develop an ACC2/FAS-coupled assay where ACC2 produces malonyl-CoA from acetyl-CoA. We miniaturized the FAS and ACC2/FAS assays to 3,456- and 1,536-well plate format, respectively, and completed uHTSs for small molecule inhibitors of this enzyme system. This report shows the results of assay development, miniaturization, and inhibitor screening for these potential drug targets.
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Chen, Wei; Zhang, Guoxian; Guo, Liang; Fan, Wenxi; Ma, Qin; Zhang, Xiaodong; Du, Runlei; Cao, Rihui
2016-11-29
We have synthesized and evaluated a series of novel alkyl diamine linked bivalent β-carbolines as potent angiogenesis inhibitors. The results demonstrated that most bivalent β-carbolines exhibited significant antiproliferative effects against human umbilical vein cell lines EA.HY926. Compound 4m was found to be the most potent antiproliferative agent with IC 50 value of 2.16 μM against EA.HY926 cell lines. Mechanism investigations revealed that compound 4m could significantly inhibit EA.HY926 cells migration and tube formation in a dose-dependent manner. Moreover, compound 4m also showed obvious angiogenesis inhibitory effects in CAM assay, and the antiangiogenetic potency was more potent than the reference drug Endostar. The bivalent β-carbolines might be served as candidates for the development of vascular targeting antitumor drugs. Copyright © 2016 Elsevier Masson SAS. All rights reserved.
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Guo, Jingsheng; Li, Dongye; Bai, Shiru; Xu, Tongda; Zhou, Zhongmin; Zhang, Yanbin
2012-12-13
Neointimal formation plays an important role in the pathogenesis of coronary restenosis after percutaneous coronary intervention (PCI), especially in patients with diabetes mellitus. Recently, some studies have shown that 5-ethynyl-2'-deoxyuridine (EdU) incorporation can serve as a novel alternative to the 5-bromo-2'-deoxyuridine (BrdU) antibody detection method for detection of DNA synthesis in regenerating avian cochlea, chick embryo and the adult nervous system. However, few studies have been performed to assess the suitability of EdU for detecting DNA synthesis in vascular neointima. The carotid artery balloon injury model was established in Goto-Kakizaki (GK) and Wistar rats. A Cell-LightTM EdU Kit was used to detect EdU-labeled cell nuclei of common carotid arteries at day 7 after catheter balloon injury. Different methods of injecting EdU were tested. The protein levels of proliferating cell nuclear antigen (PCNA) and p-Akt (Ser473), as well as the mRNA levels of PCNA were evaluated by Western blotting and quantitative real-time PCR (qRT-PCR), respectively. Immunohistochemical staining was also employed to visualize PCNA-positive cells. At day 7 after catheter balloon injury, far more EdU-positive and PCNA-positive cells were observed in GK rats. When comparing groups that received different EdU doses, it was found that the percentage of EdU-positive cells at a dose of 100 mg/kg body weight was than at doses of 25 mg/kg and 50 mg/kg. The number of positive cells was significantly higher in the repeated injection group compared to the single injection group. Further, after balloon injury DNA synthesis in GK rats was more notable than in Wistar rats. Neointimal formation in GK rats was more obvious than in Wistar rats. The protein levels of PCNA and p-Akt (Ser473) and the mRNA levels of PCNA were increased in injured rats as compared to uninjured rats, and were significantly higher in GK rats than in Wistar rats. By intraperitoneal injections of EdU at a dose
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Zulueta, Aida; Caretti, Anna; Campisi, Giuseppe Matteo; Brizzolari, Andrea; Abad, Jose Luis; Paroni, Rita; Signorelli, Paola; Ghidoni, Riccardo
2017-07-01
Exposure to cigarette smoke represents the most important risk factor for the development of chronic obstructive pulmonary disease (COPD). COPD is characterized by chronic inflammation of the airways, imbalance of proteolytic activity resulting in the destruction of lung parenchyma, alveolar hypoxia, oxidative stress, and apoptosis. Sphingolipids are structural membrane components whose metabolism is altered during stress. Known as apoptosis and inflammation inducer, the sphingolipid ceramide was found to accumulate in COPD airways and its plasma concentration increased as well. The present study investigates the role of sphingolipids in the cigarette smoke-induced damage of human airway epithelial cells. Lung epithelial cells were pre-treated with sphingolipid synthesis inhibitors (myriocin or XM462) and then exposed to a mixture of nicotine, acrolein, formaldehyde, and acetaldehyde, the major toxic cigarette smoke components. The inflammatory and proteolytic responses were investigated by analysis of the mRNA expression (RT-PCR) of cytokines IL-1β and IL-8, and matrix metalloproteinase-9 and of the protein expression (ELISA) of IL-8. Ceramide intracellular amounts were measured by LC-MS technique. Ferric-reducing antioxidant power test and superoxide anion radical scavenging activity assay were used to assess the antioxidant power of the inhibitors of ceramide synthesis. We here show that ceramide synthesis is enhanced under treatment with a cigarette smoke mixture correlating with increased expression of inflammatory cytokines and matrix metalloproteinase 9. The use of inhibitors of ceramide synthesis protected from smoke induced damages such as inflammation, oxidative stress, and proteolytic imbalance in airways epithelia.
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Lin, Hong; Erhard, Karl; Hardwicke, Mary Ann; Luengo, Juan I; Mack, James F; McSurdy-Freed, Jeanelle; Plant, Ramona; Raha, Kaushik; Rominger, Cynthia M; Sanchez, Robert M; Schaber, Michael D; Schulz, Mark J; Spengler, Michael D; Tedesco, Rosanna; Xie, Ren; Zeng, Jin J; Rivero, Ralph A
2012-03-15
A series of PI3K-beta selective inhibitors, imidazo[1,2-a]-pyrimidin-5(1H)-ones, has been rationally designed based on the docking model of the more potent R enantiomer of TGX-221, identified by a chiral separation, in a PI3K-beta homology model. Synthesis and SAR of this novel chemotype are described. Several compounds in the series demonstrated potent growth inhibition in a PTEN-deficient breast cancer cell line MDA-MB-468 under anchorage independent conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.
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Formate and its role in hydrogen production in Escherichia coli.
Sawers, R G
2005-02-01
The production of dihydrogen by Escherichia coli and other members of the Enterobacteriaceae is one of the classic features of mixed-acid fermentation. Synthesis of the multicomponent, membrane-associated FHL (formate hydrogenlyase) enzyme complex, which disproportionates formate into CO(2) and H(2), has an absolute requirement for formate. Formate, therefore, represents a signature molecule in the fermenting E. coli cell and factors that determine formate metabolism control FHL synthesis and consequently dihydrogen evolution.
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Contribution of exopeptidases to formation of nonprotein nitrogen during ensiling of alfalfa.
Tao, L; Zhou, H; Guo, X S; Long, R J; Zhu, Y; Cheng, W
2011-08-01
The experiment was conducted to investigate the exopeptidase classes in alfalfa (Medicago sativa L.) leaves, and to determine their contribution to the formation of nonprotein nitrogen (NPN) components during ensiling. Six classes of inhibitors that included bestatin (aminopeptidase inhibitor), potato carboxypeptidase inhibitor (PCI, carboxypeptidase inhibitor), 1,10-phenanthroline (dipeptidase inhibitor), diprotin A (dipeptidyl-peptidase inhibitor), butabindide (tripeptidyl-peptidase inhibitor), and dipeptide Phe-Arg (peptidyl-dipeptidase inhibitor) were used. To determine the contribution of each exopeptidase to the formation of NPN products, aqueous extracts of fresh alfalfa were fermented to imitate the proteolytic process of ensiled alfalfa and to ensure that each class of exopeptidase inhibitor would have immediate contact with the proteases in the alfalfa extract. Five classes of exopeptidases; namely, aminopeptidase, carboxypeptidase, dipeptidase, dipeptidyl-peptidase, and tripeptidyl-peptidase, were shown to be present in alfalfa leaves, each playing a different role in alfalfa protein degradation. Aminopeptidase, carboxypeptidase, and dipeptidase were the main exopeptidases contributing to the formation of NH(3)-N. Among the 5 exopeptidases, tripeptidyl-peptidase appeared to be the principal exopeptidase in hydrolyzing forage protein into peptides, whereas carboxypeptidase and dipeptidase appeared to be more important in contributing to the formation of amino acid-N. Dipeptidyl-peptidase and tripeptidyl-peptidase did not play a role in the formation of NH(3)-N or amino acid-N. Dipeptidase, carboxypeptidase, and tripeptidyl-peptidase were the principal exopeptidases for hydrolyzing forage protein into NPN during ensilage, and treatment with a mixture of the 5 inhibitors reduced the total NPN concentration in the fermented alfalfa extract to about 45% of that in the control after 21 d of fermentation. Copyright © 2011 American Dairy Science Association
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Laminin peptide YIGSR induces collagen synthesis in Hs27 human dermal fibroblasts
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yoon, Jong Hyuk; Kim, Jaeyoon; Lee, Hyeongjoo
Highlights: Black-Right-Pointing-Pointer We identify a function of the YIGSR peptide to enhance collagen synthesis in Hs27. Black-Right-Pointing-Pointer YIGSR peptide enhanced collagen type 1 synthesis both of gene and protein levels. Black-Right-Pointing-Pointer There were no changes in cell proliferation and MMP-1 level in YIGSR treatment. Black-Right-Pointing-Pointer The YIGSR effect on collagen synthesis mediated activation of FAK, pyk2 and ERK. Black-Right-Pointing-Pointer The YIGSR-induced FAK and ERK activation was modulated by FAK and MEK inhibitors. -- Abstract: The dermal ECM is synthesized from fibroblasts and is primarily compromised of fibrillar collagen and elastic fibers, which support the mechanical strength and resiliency of skin,more » respectively. Laminin, a major glycoprotein located in the basement membrane, promotes cell adhesion, cell growth, differentiation, and migration. The laminin tyrosine-isoleucine-glycine-serine-arginine (YIGSR) peptide, corresponding to the 929-933 sequence of the {beta}1 chain, is known to be a functional motif with effects on the inhibition of tumor metastasis, the regulation of sensory axonal response and the inhibition of angiogenesis through high affinity to the 67 kDa laminin receptor. In this study, we identified a novel function of the YIGSR peptide to enhance collagen synthesis in human dermal fibroblasts. To elucidate this novel function regarding collagen synthesis, we treated human dermal fibroblasts with YIGSR peptide in both a time- and dose-dependent manner. According to subsequent experiments, we found that the YIGSR peptide strongly enhanced collagen type 1 synthesis without changing cell proliferation or cellular MMP-1 level. This YIGSR peptide-mediated collagen type 1 synthesis was modulated by FAK inhibitor and MEK inhibitor. This study clearly reveals that YIGSR peptide plays a novel function on the collagen type 1 synthesis of dermal fibroblasts and also suggests that YIGSR is a strong
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Bulk synthesis of silver nanorods employing poly (ethylene glycol) (PEG) under microwave irradiation is reported. The formation of nanorods or particulate morphology is dependent on the PEG concentration. This greener method uses no surfactants or reducing agents and employs a b...
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NASA Astrophysics Data System (ADS)
Fuse, Shinichiro; Mifune, Yuto; Nakamura, Hiroyuki; Tanaka, Hiroshi
2016-11-01
Feglymycin is a naturally occurring, anti-HIV and antimicrobial 13-mer peptide that includes highly racemizable 3,5-dihydroxyphenylglycines (Dpgs). Here we describe the total synthesis of feglymycin based on a linear/convergent hybrid approach. Our originally developed micro-flow amide bond formation enabled highly racemizable peptide chain elongation based on a linear approach that was previously considered impossible. Our developed approach will enable the practical preparation of biologically active oligopeptides that contain highly racemizable amino acids, which are attractive drug candidates.
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Synthesis and investigation of dihydroxychalcones as calpain and cathepsin inhibitors.
Baek, Kyung Hye; Karki, Radha; Lee, Eung-Seok; Na, Younghwa; Kwon, Youngjoo
2013-12-01
In order to identify potential calpain and cathepsin inhibitors we prepared 12 dihydroxychalcone analogues and tested their ability to inhibit μ-calpain, m-calpain, cathepsins B and L. In the calpain inhibition test, compound 10 exhibited the most active inhibitory activity against m-calpain with an IC50 value of 25.25±0.901μM. With respect to inhibition of cathepsins B and L, compound 13 exhibited the most potent inhibitory activity on cathepsin L and moderate inhibitory activity on cathepsin B with IC50 values of 2.80±0.100 and 11.47±0.087μM, respectively. Our results suggest the possibility of developing dual calpain and cathepsin inhibitors by properly modulating structures and/or combining the essential aspects of the functional group effective for specific calpain and cathepsin inhibition. Copyright © 2013 Elsevier Inc. All rights reserved.
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Discovery of DF-461, a Potent Squalene Synthase Inhibitor
2013-01-01
We report the development of a new trifluoromethyltriazolobenzoxazepine series of squalene synthase inhibitors. Structure–activity studies and pharmacokinetics optimization on this series led to the identification of compound 23 (DF-461), which exhibited potent squalene synthase inhibitory activity, high hepatic selectivity, excellent rat hepatic cholesterol synthesis inhibitory activity, and plasma lipid lowering efficacy in nonrodent repeated dose studies. PMID:24900587
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Pecic, Stevan; Pakhomova, Svetlana; Newcomer, Marcia E.
2013-09-27
A series of potent amide non-urea inhibitors of soluble epoxide hydrolase (sEH) is disclosed. The inhibition of soluble epoxide hydrolase leads to elevated levels of epoxyeicosatrienoic acids (EETs), and thus inhibitors of sEH represent one of a novel approach to the development of vasodilatory and anti-inflammatory drugs. Structure–activities studies guided optimization of a lead compound, identified through high-throughput screening, gave rise to sub-nanomolar inhibitors of human sEH with stability in human liver microsomal assay suitable for preclinical development.
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Wang, Yijin; Wang, Wenshi; Xu, Lei; Zhou, Xinying; Shokrollahi, Ehsan; Felczak, Krzysztof; van der Laan, Luc J. W.; Pankiewicz, Krzysztof W.; Sprengers, Dave; Raat, Nicolaas J. H.; Metselaar, Herold J.; Peppelenbosch, Maikel P.
2016-01-01
Viruses are solely dependent on host cells to propagate; therefore, understanding virus-host interaction is important for antiviral drug development. Since de novo nucleotide biosynthesis is essentially required for both host cell metabolism and viral replication, specific catalytic enzymes of these pathways have been explored as potential antiviral targets. In this study, we investigated the role of different enzymatic cascades of nucleotide biosynthesis in hepatitis E virus (HEV) replication. By profiling various pharmacological inhibitors of nucleotide biosynthesis, we found that targeting the early steps of the purine biosynthesis pathway led to the enhancement of HEV replication, whereas targeting the later step resulted in potent antiviral activity via the depletion of purine nucleotide. Furthermore, the inhibition of the pyrimidine pathway resulted in potent anti-HEV activity. Interestingly, all of these inhibitors with anti-HEV activity concurrently triggered the induction of antiviral interferon-stimulated genes (ISGs). Although ISGs are commonly induced by interferons via the JAK-STAT pathway, their induction by nucleotide synthesis inhibitors is completely independent of this classical mechanism. In conclusion, this study revealed an unconventional novel mechanism of cross talk between nucleotide biosynthesis pathways and cellular antiviral immunity in constraining HEV infection. Targeting particular enzymes in nucleotide biosynthesis represents a viable option for antiviral drug development against HEV. HEV is the most common cause of acute viral hepatitis worldwide and is also associated with chronic hepatitis, especially in immunocompromised patients. Although often an acute and self-limiting infection in the general population, HEV can cause severe morbidity and mortality in certain patients, a problem compounded by the lack of FDA-approved anti-HEV medication available. In this study, we have investigated the role of the nucleotide synthesis pathway
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Protein Phosphatase-1 Inhibitor-2 Is a Novel Memory Suppressor.
Yang, Hongtian; Hou, Hailong; Pahng, Amanda; Gu, Hua; Nairn, Angus C; Tang, Ya-Ping; Colombo, Paul J; Xia, Houhui
2015-11-11
Reversible phosphorylation, a fundamental regulatory mechanism required for many biological processes including memory formation, is coordinated by the opposing actions of protein kinases and phosphatases. Type I protein phosphatase (PP1), in particular, has been shown to constrain learning and memory formation. However, how PP1 might be regulated in memory is still not clear. Our previous work has elucidated that PP1 inhibitor-2 (I-2) is an endogenous regulator of PP1 in hippocampal and cortical neurons (Hou et al., 2013). Contrary to expectation, our studies of contextual fear conditioning and novel object recognition in I-2 heterozygous mice suggest that I-2 is a memory suppressor. In addition, lentiviral knock-down of I-2 in the rat dorsal hippocampus facilitated memory for tasks dependent on the hippocampus. Our data indicate that I-2 suppresses memory formation, probably via negatively regulating the phosphorylation of cAMP/calcium response element-binding protein (CREB) at serine 133 and CREB-mediated gene expression in dorsal hippocampus. Surprisingly, the data from both biochemical and behavioral studies suggest that I-2, despite its assumed action as a PP1 inhibitor, is a positive regulator of PP1 function in memory formation. We found that inhibitor-2 acts as a memory suppressor through its positive functional influence on type I protein phosphatase (PP1), likely resulting in negative regulation of cAMP/calcium response element-binding protein (CREB) and CREB-activated gene expression. Our studies thus provide an interesting example of a molecule with an in vivo function that is opposite to its in vitro function. PP1 plays critical roles in many essential physiological functions such as cell mitosis and glucose metabolism in addition to its known role in memory formation. PP1 pharmacological inhibitors would thus not be able to serve as good therapeutic reagents because of its many targets. However, identification of PP1 inhibitor-2 as a critical
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Bergström, Tomas; Kann, Nina; Adamiak, Beata; Hannoun, Charles; Kindler, Eveline; Jónsdóttir, Hulda R.; Muth, Doreen; Kint, Joeri; Forlenza, Maria; Müller, Marcel A.; Drosten, Christian; Thiel, Volker; Trybala, Edward
2014-01-01
Coronaviruses raise serious concerns as emerging zoonotic viruses without specific antiviral drugs available. Here we screened a collection of 16671 diverse compounds for anti-human coronavirus 229E activity and identified an inhibitor, designated K22, that specifically targets membrane-bound coronaviral RNA synthesis. K22 exerts most potent antiviral activity after virus entry during an early step of the viral life cycle. Specifically, the formation of double membrane vesicles (DMVs), a hallmark of coronavirus replication, was greatly impaired upon K22 treatment accompanied by near-complete inhibition of viral RNA synthesis. K22-resistant viruses contained substitutions in non-structural protein 6 (nsp6), a membrane-spanning integral component of the viral replication complex implicated in DMV formation, corroborating that K22 targets membrane bound viral RNA synthesis. Besides K22 resistance, the nsp6 mutants induced a reduced number of DMVs, displayed decreased specific infectivity, while RNA synthesis was not affected. Importantly, K22 inhibits a broad range of coronaviruses, including Middle East respiratory syndrome coronavirus (MERS–CoV), and efficient inhibition was achieved in primary human epithelia cultures representing the entry port of human coronavirus infection. Collectively, this study proposes an evolutionary conserved step in the life cycle of positive-stranded RNA viruses, the recruitment of cellular membranes for viral replication, as vulnerable and, most importantly, druggable target for antiviral intervention. We expect this mode of action to serve as a paradigm for the development of potent antiviral drugs to combat many animal and human virus infections. PMID:24874215
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Structure-Based Design of Novel HIV-1 Protease Inhibitors to Combat Drug Resistance
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ghosh,A.; Sridhar, P.; Leshchenko, S.
2006-01-01
Structure-based design and synthesis of novel HIV protease inhibitors are described. The inhibitors are designed specifically to interact with the backbone of HIV protease active site to combat drug resistance. Inhibitor 3 has exhibited exceedingly potent enzyme inhibitory and antiviral potency. Furthermore, this inhibitor maintains impressive potency against a wide spectrum of HIV including a variety of multi-PI-resistant clinical strains. The inhibitors incorporated a stereochemically defined 5-hexahydrocyclopenta[b]furanyl urethane as the P2-ligand into the (R)-(hydroxyethylamino)sulfonamide isostere. Optically active (3aS,5R,6aR)-5-hydroxy-hexahydrocyclopenta[b]furan was prepared by an enzymatic asymmetrization of meso-diacetate with acetyl cholinesterase, radical cyclization, and Lewis acid-catalyzed anomeric reduction as the key steps.more » A protein-ligand X-ray crystal structure of inhibitor 3-bound HIV-1 protease (1.35 Angstroms resolution) revealed extensive interactions in the HIV protease active site including strong hydrogen bonding interactions with the backbone. This design strategy may lead to novel inhibitors that can combat drug resistance.« less
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Synthesis and Characterization of Compounds Related to Lisinopril
Raghava Reddy, Ambati V.; Garaga, Srinivas; Takshinamoorthy, Chandiran; Naidu, Andra; Dandala, Ramesh
2016-01-01
Lisinopril is a drug of the angiotensin-converting enzyme (ACE) inhibitor class that is primarily used in the treatment of hypertension. During the scale-up of the lisinopril process, one unknown impurity was observed and is identified. The present work describes the origin, synthesis, characterization, and control of this impurity. This paper also describes the synthesis and characterization of three other impurities listed in the European Pharmacopoeia 8.4 (Impurity C, D, and F). PMID:27222603
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How polyamine synthesis inhibitors and cinnamic acid affect tropane alkaloid production.
Marconi, Patricia L; Alvarez, María A; Pitta-Alvarez, Sandra I
2007-01-01
Hairy roots of Brugmansia candida produce the tropane alkaloids scopolamine and hyoscyamine. In an attempt to divert the carbon flux from competing pathways and thus enhance productivity, the polyamine biosynthesis inhibitors cyclohexylamine (CHA) and methylglyoxal-bis-guanylhydrazone (MGBG) and the phenylalanine-ammonia-lyase inhibitor cinnamic acid were used. CHA decreased the specific productivity of both alkaloids but increased significantly the release of scopolamine (approx 500%) when it was added in the mid-exponential phase. However, when CHA was added for only 48 h during the exponential phase, the specific productivity of both alkaloids increased (approx 200%), favoring scopolamine. Treatment with MGBG was detrimental to growth but promoted release into the medium of both alkaloids. However, when it was added for 48 h during the exponential phase, MGBG increased the specific productivity (approx 200%) and release (250- 1800%) of both alkaloids. Cinnamic acid alone also favored release but not specific productivity. When a combination of CHA or MGBG with cinnamic acid was used, the results obtained were approximately the same as with each polyamine biosynthesis inhibitor alone, although to a lesser extent. Regarding root morphology, CHA inhibited growth of primary roots and ramification. However, it had a positive effect on elongation of lateral roots.
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Synthesis and PET studies of [(11)C-cyano]letrozole (Femara), an aromatase inhibitor drug.
Kil, Kun-Eek; Biegon, Anat; Ding, Yu-Shin; Fischer, Andre; Ferrieri, Richard A; Kim, Sung Won; Pareto, Deborah; Schueller, Michael J; Fowler, Joanna S
2009-02-01
Aromatase, a member of the cytochrome P450 family, converts androgens such as androstenedione and testosterone into estrone and estradiol, respectively. Letrozole (1-[bis-(4-cyanophenyl)methyl]-1H-1,2,4-triazole; Femara) is a high-affinity aromatase inhibitor (K(i)=11.5 nM) that has Food and Drug Administration approval for breast cancer treatment. Here we report the synthesis of carbon-11-labeled letrozole and its assessment as a radiotracer for brain aromatase in the baboon. Letrozole and its precursor (4-[(4-bromophenyl)-1H-1,2,4-triazol-1-ylmethyl]benzonitrile) were prepared in a two-step synthesis from 4-cyanobenzyl bromide and 4-bromobenzyl bromide, respectively. The [(11)C]cyano group was introduced via tetrakis(triphenylphosphine)palladium(0)-catalyzed coupling of [(11)C]cyanide with the bromo precursor. Positron emission tomography (PET) studies in the baboon brain were carried out to assess regional distribution and kinetics, reproducibility of repeated measures and saturability. Log D, the free fraction of letrozole in plasma and the [(11)C-cyano]letrozole fraction in arterial plasma were also measured. [(11)C-cyano]Letrozole was synthesized in 60 min with a radiochemical yield of 79-80%, with a radiochemical purity greater than 98% and a specific activity of 4.16+/-2.21 Ci/mumol at the end of bombardment (n=4). PET studies in the baboon revealed initial rapid and high uptake and initial rapid clearance, followed by slow clearance of carbon-11 from the brain, with no difference between brain regions. Brain kinetics was not affected by coinjection of unlabeled letrozole (0.1 mg/kg). The free fraction of letrozole in plasma was 48.9%, and log D was 1.84. [(11)C-cyano]Letrozole is readily synthesized via a palladium-catalyzed coupling reaction with [(11)C]cyanide. Although it is unsuitable as a PET radiotracer for brain aromatase, as revealed by the absence of regional specificity and saturability in brain regions such as amygdala, which are known to
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Luthra, Priya; Liang, Jue; Pietzsch, Colette A; Khadka, Sudip; Edwards, Megan R; Wei, Shuguang; De, Sampriti; Posner, Bruce; Bukreyev, Alexander; Ready, Joseph M; Basler, Christopher F
2018-02-01
Ebola virus (EBOV) is an enveloped negative-sense, single-stranded RNA virus of the filovirus family that causes severe disease in humans. Approved therapies for EBOV disease are lacking. EBOV RNA synthesis is carried out by a virus-encoded complex with RNA-dependent RNA polymerase activity that is required for viral propagation. This complex and its activities are therefore potential antiviral targets. To identify potential lead inhibitors of EBOV RNA synthesis, a library of small molecule compounds was screened against a previously established assay of EBOV RNA synthesis, the EBOV minigenome assay (MGA), in 384 well microplate format. The screen identified 56 hits that inhibited EBOV MGA activity by more than 70% while exhibiting less than 20% cell cytotoxicity. Inhibitory chemical scaffolds included angelicin derivatives, derivatives of the antiviral compound GSK983 and benzoquinolines. Structure-activity relationship (SAR) studies of the benzoquinoline scaffold produced ∼50 analogs and led to identification of an optimized compound, SW456, with a submicromolar IC 50 in the EBOV MGA and antiviral activity against infectious EBOV in cell culture. The compound was also active against a MGA for another deadly filovirus, Marburg virus. It also exhibited antiviral activity towards a negative-sense RNA virus from the rhabdovirus family, vesicular stomatitis virus, and a positive-sense RNA virus, Zika virus. Overall, these data demonstrate the potential of the EBOV MGA to identify anti-EBOV compounds and identifies the benzoquinoline series as a broad-spectrum antiviral lead. Copyright © 2017. Published by Elsevier B.V.
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Plaga, W; Frank, R; Knappe, J
1988-12-15
Pyruvate formate-lyase of Escherichia coli cells, a homodimeric protein of 2 x 85 kDa, is distinguished by the property of containing a stable organic free radical (g = 2.0037) in its resting state. The enzyme (E-SH) achieves pyruvate conversion to acetyl-CoA via two distinct half-reactions (E-SH + pyruvate in equilibrium E-S-acetyl + formate; E-S-acetyl + CoA in equilibrium E-SH + acetyl-CoA), the first of which has been proposed to involve reversible homolytic carbon-carbon bond cleavage [J. Knappe et al. (1984) Proc. Natl Acad. Sci. USA 81, 1332-1335]. Present studies identified Cys-419 as the covalent-catalytic cysteinyl residue via CNBr fragmentation of E-S-[14C]acetyl and radio-sequencing of the isolated peptide CB-Ac (amino acid residues 406-423). Reaction of the formate analogue hypophosphite with E-S-acetyl was investigated and found to produce 1-hydroxyethylphosphonate with a thioester linkage to the adjacent Cys-418. The structure was determined from the chymotryptic peptide CH-P (amino acid residues 415-425), using 31P-NMR spectroscopy (delta = 44 ppm) and by chemical characterisation through degradation into 1-hydroxyethylphosphonate with phosphodiesterase or bromine. This novel P-C-bond synthesis involves the enzyme-based free radical and is proposed to resemble the physiological C-C-bond synthesis (pyruvate production) from formate and E-S-acetyl. These findings are interpreted as proof of a radical mechanism for the action of pyruvate formate-lyase. The central Cys-418/Cys-419 pair of the active site shows a distinctive thiolate property even in the inactive (nonradical) form of the enzyme, as determined using an iodoacetate probe.
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Synthesis and Biological Evaluation of Botulinum Neurotoxin A Protease Inhibitors
Li, Bing; Pai, Ramdas; Cardinale, Steven C.; Butler, Michelle M.; Peet, Norton P.; Moir, Donald T.; Bavari, Sina; Bowlin, Terry L.
2010-01-01
NSC 240898 was previously identified as a botulinum neurotoxin A light chain (BoNT/A LC) endopeptidase inhibitor by screening the National Cancer Institute Open Repository diversity set. Two types of analogs have been synthesized and shown to inhibit BoNT/A LC in a FRET-based enzyme assay, with confirmation in an HPLC-based assay. These two series of compounds have also been evaluated for inhibition of anthrax lethal factor (LF), an unrelated metalloprotease, to examine enzyme specificity of the BoNT/A LC inhibition. The most potent inhibitor against BoNT/A LC in these two series is compound 12 (IC50 = 2.5 µM, FRET assay), which is 4.4-fold more potent than the lead structure, and 11.2-fold more selective for BoNT/A LC versus the anthrax LF metalloproteinase. Structure-activity relationship studies have revealed structural features important to potency and enzyme specificity. PMID:20155918
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Combination of Pim kinase inhibitor SGI-1776 and bendamustine in B-cell lymphoma.
Yang, Qingshan; Chen, Lisa S; Neelapu, Sattva S; Gandhi, Varsha
2013-09-01
SGI-1776 is a small-molecule Pim kinase inhibitor that primarily targets c-MYC-driven transcription and cap-dependent translation in mantle cell lymphoma (MCL) cells. Bendamustine is an alkylating chemotherapeutic agent approved for use in B-cell lymphoma that is known to induce DNA damage and initiate response to repair. Our studies were conducted in MCL cell lines JeKo-1 and Mino, as well as primary B-cell lymphoma samples of MCL and splenic marginal zone lymphoma (SMZL), where we treated cells with SGI-1776 and bendamustine. We measured levels of cellular apoptosis, macromolecule synthesis inhibition, and DNA damage induced by drug treatments. Both SGI-1776 and bendamustine effectively induced apoptosis as single agents, and when used in combination, an additive effect in cell killing was observed in MCL cell lines JeKo-1 and Mino, as well as in MCL and SMZL primary cells. As expected, SGI-1776 was effective in inducing a decrease of global RNA and protein synthesis, and bendamustine significantly inhibited DNA synthesis and generated a DNA damage response. When used in combination, the effects were intensified in DNA, RNA, and protein synthesis inhibition compared with single-agent treatments. These data provide a foundation and suggest the feasibility of using Pim kinase inhibitors in combination with chemotherapeutic agents such as bendamustine in B-cell lymphoma. Copyright © 2013 Elsevier Inc. All rights reserved.
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Developing Inhibitors of Translesion DNA Synthesis as Therapeutic Agents against Lung Cancer
2015-12-01
normal DNA synthesis. In contrast, pol eta shows a combination of high efficiency and low fidelity when replicating 8-oxo-G. These combined properties...are consistent with a pro- mutagenic role for pol eta when replicating this DNA lesion under cellular conditions. Studies with modified nucleotide...analogs indicate that pol eta relies heavily on hydrogen-bonding interactions during normal and translesion synthesis. However, some nucleobase
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Morizot, Arnaud P; Neville, Anne
2002-01-01
Polycarboxylic acid (PAA), a common scale inhibitor has demonstrated adsorption properties on stainless steel surfaces. An electrochemically based technique has been used to assess the extent of film formation. The presence of calcium and magnesium ions in the solution and the cathodic electrochemical activity at the metal surface have been shown to enhance the inhibitor film formation by promoting the transport of the inhibitor from the solution to the metal surface. The effect of the inhibitor film in retarding scale deposition is assessed using measurement of the deposition onto metal electrodes immersed in a supersaturated solution of CaCO(3). The practical implications of these findings are discussed.
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Cell-Free, De Nova Synthesis of Poliovirus
NASA Astrophysics Data System (ADS)
Molla, Akhteruzzaman; Paul, Aniko V.; Wimmer, Eckard
1991-12-01
Cell-free translation of poliovirus RNA in an extract of uninfected human (HeLa) cells yielded viral proteins through proteolysis of the polyprotein. In the extract, newly synthesized proteins catalyzed poliovirus-specific RNA synthesis, and formed infectious poliovirus de novo. Newly formed virions were neutralized by type-specific antiserum, and infection of human cells with them was prevented by poliovirus receptor-specific antibodies. Poliovirus synthesis was increased nearly 70-fold when nucleoside triphosphates were added, but it was abolished in the presence of inhibitors of translation or viral genome replication. The ability to conduct cell-free synthesis of poliovirus will aid in the study of picornavirus proliferation and in the search for the control of picornaviral disease.
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Erkel, G; Anke, T; Velten, R; Steglich, W
1991-01-01
A novel enzyme inhibitor of RNA-directed DNA-polymerases of avian myeloblastosis and murine leukemia virus was isolated from fermentations of an tasmanian Podoscypha species. Its structure was elucidated by spectroscopic methods and oxidative degradation as (E)-4,5-dioxo-2-hexadecenoic acid (1). The enzyme inhibitor, which was named podoscyphic acid, did not inhibit DNA and RNA synthesis in permeabilized L 1210 cells nor did it affect RNA synthesis in isolated nuclei of L 1210 cells. 1 inhibits protein synthesis in whole L 1210 cells and rabbit reticulocyte lysate and shows very weak antimicrobial and cytotoxic properties. The testing of ethyl (E)-4,5-dioxo-2-hexadecenoate (2) and (E)-4-oxo-2-tetradecenoic acid (11) revealed the importance of the free gamma-oxoacrylic acid unit for the biological activities of 1.
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Effects of proteasome inhibitors MG132, ZL3VS and AdaAhx3L3VS on protein metabolism in septic rats
Kadlčíková, Jana; Holeček, Milan; Šafránek, Roman; Tilšer, Ivan; Kessler, Benedikt M
2004-01-01
Proteasome inhibitors are novel therapeutic agents for the treatment of cancer and other severe disorders. One of the possible side effects is influencing the metabolism of proteins. The aim of our study was to evaluate the influence of three proteasome inhibitors MG132, ZL3VS and AdaAhx3L3VS on protein metabolism and leucine oxidation in incubated skeletal muscle of control and septic rats. Total proteolysis was determined according to the rates of tyrosine release into the medium during incubation. The rates of protein synthesis and leucine oxidation were measured in a medium containing L-[1-14C]leucine. Protein synthesis was determined as the amount of L-[1-14C]leucine incorporated into proteins, and leucine oxidation was evaluated according to the release of 14CO2 during incubation. Sepsis was induced in rats by means of caecal ligation and puncture. MG132 reduced proteolysis by more than 50% and protein synthesis by 10–20% in the muscles of healthy rats. In septic rats, proteasome inhibitors, except ZL3VS, decreased proteolysis in both soleus and extensor digitorum longus (EDL) muscles, although none of the inhibitors had any effect on protein synthesis. Leucine oxidation was increased by AdaAhx3L3VS in the septic EDL muscle and decreased by MG132 in intact EDL muscle. We conclude that MG132 and AdaAhx3L3VS reversed protein catabolism in septic rat muscles. PMID:15566433
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Fredrick, Chase M; Lin, Guangyun; Johnson, Eric A
2017-07-01
Botulinum neurotoxin (BoNT), produced by neurotoxigenic clostridia, is the most potent biological toxin known and the causative agent of the paralytic disease botulism. The nutritional, environmental, and genetic regulation of BoNT synthesis, activation, stability, and toxin complex (TC) formation is not well studied. Previous studies indicated that growth and BoNT formation were affected by arginine and glucose in Clostridium botulinum types A and B. In the present study, C. botulinum ATCC 3502 was grown in toxin production medium (TPM) with different levels of arginine and glucose and of three products of arginine metabolism, citrulline, proline, and ornithine. Cultures were analyzed for growth (optical density at 600 nm [OD 600 ]), spore formation, and BoNT and TC formation by Western blotting and immunoprecipitation and for BoNT activity by mouse bioassay. A high level of arginine (20 g/liter) repressed BoNT production approximately 1,000-fold, enhanced growth, slowed lysis, and reduced endospore production by greater than 1,000-fold. Similar effects on toxin production were seen with equivalent levels of citrulline but not ornithine or proline. In TPM lacking glucose, levels of formation of BoNT/A1 and TC were significantly decreased, and extracellular BoNT and TC proteins were partially inactivated after the first day of culture. An understanding of the regulation of C. botulinum growth and BoNT and TC formation should be valuable in defining requirements for BoNT formation in foods and clinical samples, improving the quality of BoNT for pharmaceutical preparations, and elucidating the biological functions of BoNTs for the bacterium. IMPORTANCE Botulinum neurotoxin (BoNT) is a major food safety and bioterrorism concern and is also an important pharmaceutical, and yet the regulation of its synthesis, activation, and stability in culture media, foods, and clinical samples is not well understood. This paper provides insights into the effects of critical
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Zhang, Ruilan; Wang, Lei; Zhang, Li; Chen, Jieli; Zhu, Zhenping; Zhang, Zhenggang; Chopp, Michael
2003-02-21
We investigated the effects of NO on angiogenesis and the synthesis of vascular endothelial growth factor (VEGF) in a model of focal embolic cerebral ischemia in the rat. Compared with control rats, systemic administration of an NO donor, DETANONOate, to rats 24 hours after stroke significantly enlarged vascular perimeters and increased the number of proliferated cerebral endothelial cells and the numbers of newly generated vessels in the ischemic boundary regions, as evaluated by 3-dimensional laser scanning confocal microscopy. Treatment with DETANONOate significantly increased VEGF levels in the ischemic boundary regions as measured by ELISA. A capillary-like tube formation assay was used to investigate whether DETANONOate increases angiogenesis in ischemic brain via activation of soluble guanylate cyclase. DETANONOate-induced capillary-like tube formation was completely inhibited by a soluble guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ). Blocking VEGF activity by a neutralized antibody against VEGF receptor 2 significantly attenuated DETANONOate-induced capillary-like tube formation. Moreover, systemic administration of a phosphodiesterase type 5 inhibitor (Sildenafil) to rats 24 hours after stroke significantly increased angiogenesis in the ischemic boundary regions. Sildenafil and an analog of cyclic guanosine monophosphate (cGMP) also induced capillary-like tube formation. These findings suggest that exogenous NO enhances angiogenesis in ischemic brain, which is mediated by the NO/cGMP pathway. Furthermore, our data suggest that NO, in part via VEGF, may enhance angiogenesis in ischemic brain.
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Soragni, Elisabetta; Chou, C. James; Rusche, James R.; Gottesfeld, Joel M.
2015-01-01
The genetic defect in Friedreich’s ataxia (FRDA) is the hyperexpansion of a GAA•TTC triplet in the first intron of the FXN gene, encoding the essential mitochondrial protein frataxin. Histone post-translational modifications near the expanded repeats are consistent with heterochromatin formation and consequent FXN gene silencing. Using a newly developed human neuronal cell model, derived from patient-induced pluripotent stem cells, we find that 2-aminobenzamide histone deacetylase (HDAC) inhibitors increase FXN mRNA levels and frataxin protein in FRDA neuronal cells. However, only compounds targeting the class I HDACs 1 and 3 are active in increasing FXN mRNA in these cells. Structural analogs of the active HDAC inhibitors that selectively target either HDAC1 or HDAC3 do not show similar increases in FXN mRNA levels. To understand the mechanism of action of these compounds, we probed the kinetic properties of the active and inactive inhibitors, and found that only compounds that target HDACs 1 and 3 exhibited a slow-on/slow-off mechanism of action for the HDAC enzymes. HDAC1- and HDAC3-selective compounds did not show this activity. Using siRNA methods in the FRDA neuronal cells, we show increases in FXN mRNA upon silencing of either HDACs 1 or 3, suggesting the possibility that inhibition of each of these class I HDACs is necessary for activation of FXN mRNA synthesis, as there appears to be redundancy in the silencing mechanism caused by the GAA•TTC repeats. Moreover, inhibitors must have a long residence time on their target enzymes for this activity. By interrogating microarray data from neuronal cells treated with inhibitors of different specificity, we selected two genes encoding histone macroH2A (H2AFY2) and Polycomb group ring finger 2 (PCGF2) that were specifically down-regulated by the inhibitors targeting HDACs1 and 3 versus the more selective inhibitors for further investigation. Both genes are involved in transcriptional repression and we
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Synthesis of [{sup 18}F]Ro41-0960, a potent COMT inhibitor, for use in vivo mapping with PET
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ding, Y.S.; Sugano, Y.; Gatley, S.J.
1995-05-01
Catechol-O-methyltransferase (COMPT; EC 2.1.1.6) is one of the two major enzymes which metabolize the catecholamine neurotransmitters. It is distributed throughout the body and brain and is elevated in breast cancer tissue when it plays a role in estrogen metabolism. It is also an important molecular target in the development of drugs to treat Parkinson`s disease (PD). Because COMT regulates the concentration of important neurotransmitter amines such as dopamine, there is speculation that abnormalities in its activity may be associated with neurological, and psychiatric disorders. Ro41-9060(3,4-dihydroxy-5-nitro-2{prime}-fluorobenzophenone) is a potent, fluorine containing COMT inhibitor which has been reported to cross the bloodmore » brain barrier. It is structurally similar to Ro40-7592 which is currently undergoing clinical trials in PD. We report the synthesis of [{sup 18}F]Ro41-0960, for investigation for mapping COMT and for studies of COMT drugs. [{sup 18}F]Ro41-0960 was synthesized by the nucleophilic aromatic substitution reaction with NCA [{sup 18}F] fluoride on a protected precursor (prepared via a five-step synthesis) followed by hydrolysis with HBr (synthesis time of 100 min; radiochemical yield of 5-7% (EOB)). Though Ro41-0960 has been reported to cross the blood brain barrier, PET studies in baboon demonstrated that an almost complete absence of the drug from the brain both at tracer doses and with the addition of unlabeled drug (1.5 mg/kg) at all times through a 90 min experimental interval. The plasma to brain ratios of F-18 average about 40:1. However, high uptake was observed in the kidneys and in other organs which are known to have high COMT. Studies in mice showed that at 30 min after injection of tracer, F-18 in kidneys was largely as [{sup 18}F]Ro-41-0960 and that it could be displaced with unlabeled Ro41-0960. These studies provide the first example of a positron emitter labeled COMT radiotracer.« less
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Igarashi, K; Morris, D R
1984-11-01
Previous results have suggested that ethylglyoxal bis(guanylhydrazone) is a more specific inhibitor of polyamine biosynthesis than the widely used methylglyoxal bis(guanylhydrazone). The physiological effects on mitogenically activated lymphocytes of polyamine depletion with ethylglyoxal bis(guanylhydrazone) were examined. In the presence of ethylglyoxal bis(guanylhydrazone) and the ornithine decarboxylase inhibitor alpha-difluoromethylornithine, the cellular contents of putrescine, spermidine, and spermine were decreased by 75 to 90, 65 to 80, and 40 to 60%, respectively, compared with control cultures. Inhibition of DNA synthesis in these polyamine-deficient cells was always greater than that of protein synthesis. Upon addition of spermidine to the deficient cells, the cellular spermidine content was restored within 4 hr, but the complete recovery of macromolecular synthesis took 10 to 20 hr. Thymidine kinase and DNA polymerase alpha activities in polyamine-deficient cells were lower than those in normal cells, whereas RNA polymerase II and leucyl transfer RNA synthase activities were nearly equal to those in normal cells. These results and studies with 2-dimensional gel electrophoresis raise the possibility that polyamines may regulate the synthesis of specific proteins. Decreased synthesis of replication proteins in polyamine-deficient cells may be one reason for the reduced synthesis of DNA.
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Detonation Synthesis of Alpha-Variant Silicon Carbide
NASA Astrophysics Data System (ADS)
Langenderfer, Martin; Johnson, Catherine; Fahrenholtz, William; Mochalin, Vadym
2017-06-01
A recent research study has been undertaken to develop facilities for conducting detonation synthesis of nanomaterials. This process involves a familiar technique that has been utilized for the industrial synthesis of nanodiamonds. Developments through this study have allowed for experimentation with the concept of modifying explosive compositions to induce synthesis of new nanomaterials. Initial experimentation has been conducted with the end goal being synthesis of alpha variant silicon carbide (α-SiC) in the nano-scale. The α-SiC that can be produced through detonation synthesis methods is critical to the ceramics industry because of a number of unique properties of the material. Conventional synthesis of α-SiC results in formation of crystals greater than 100 nm in diameter, outside nano-scale. It has been theorized that the high temperature and pressure of an explosive detonation can be used for the formation of α-SiC in the sub 100 nm range. This paper will discuss in detail the process development for detonation nanomaterial synthesis facilities, optimization of explosive charge parameters to maximize nanomaterial yield, and introduction of silicon to the detonation reaction environment to achieve first synthesis of nano-sized alpha variant silicon carbide.
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Herman, Andrzej P.; Krawczyńska, Agata; Antushevich, Hanna
2014-01-01
The study was designed to determine the effects of peripheral injection of SB203580 on the synthesis of interleukin- (IL-) 1β, IL-6, and tumor necrosis factor (TNF) α in the hypothalamus of ewes during prolonged inflammation. Inflammation was induced by the administration of lipopolysaccharide (LPS) (400 ng/kg) over 7 days. SB203580 is a selective ATP-competitive inhibitor of the p38 mitogen-activated protein kinase (MAPK), which is involved in the regulation of proinflammatory cytokines IL-1β, IL-6 and TNFα synthesis. Intravenous injection of SB203580 successfully inhibited (P < 0.01) synthesis of IL-1β and reduced (P < 0.01) the production of IL-6 in the hypothalamus. The p38 MAPK inhibitor decreased (P < 0.01) gene expression of TNFα but its effect was not observed at the level of TNFα protein synthesis. SB203580 also reduced (P < 0.01) LPS-stimulated IL-1 receptor type 1 gene expression. The conclusion that inhibition of p38 MAPK blocks LPS-induced proinflammatory cytokine synthesis seems to initiate new perspectives in the treatment of chronic inflammatory diseases also within the central nervous system. However, potential proinflammatory effects of SB203580 treatment suggest that all therapies using p38 MAPK inhibitors should be introduced very carefully with analysis of all expected and unexpected consequences of treatment. PMID:24995301
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do Nascimento, Antonio Rogério Bezerra; Farias, Juliano Ricardo; Bernardi, Daniel; Horikoshi, Renato Jun; Omoto, Celso
2016-04-01
An understanding of the genetic basis of insect resistance to insecticides is important for the establishment of insect resistance management (IRM) strategies. In this study we evaluated the inheritance pattern of resistance to the chitin synthesis inhibitor lufenuron in Spodoptera frugiperda. The LC50 values (95% CI) were 0.23 µg lufenuron mL(-1) water (ppm) (0.18-0.28) for the susceptible strain (SUS) and 210.6 µg mL(-1) (175.90-258.10) for the lufenuron-resistant strain (LUF-R), based on diet-overlay bioassay. The resistance ratio was ≈ 915-fold. The LC50 values for reciprocal crosses were 4.89 µg mL(-1) (3.79-5.97) for female LUF-R and male SUS and 5.74 µg mL(-1) (4.70-6.91) for female SUS and male LUF-R, indicating that the inheritance of S. frugiperda resistance to lufenuron is an autosomal, incompletely recessive trait. Backcrosses of the progeny of reciprocal crosses with the parental LUF-R showed a polygenic effect. The estimated minimum number of independent segregations was in the 11.02 range, indicating that resistance to lufenuron is associated with multiple genes in S. frugiperda. Based on genetic crosses, the inheritance pattern of lufenuron resistance in S. frugiperda was autosomal, incompletely recessive and polygenic. Implications of this finding to IRM are discussed in this paper. © 2015 Society of Chemical Industry.
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Bahta, Medhanit; Liu, Fa; Kim, Sung-Eun; Stephen, Andrew G.; Fisher, Robert J.; Burke, Terrence R.
2013-01-01
The described oxime-based library protocol provides detailed procedures for the linkage of aminooxy functionality with aldehyde building blocks that result in the generation of libraries of multidentate inhibitors. Synthesis of inhibitors for protein tyrosine phosphatases (PTPs) and antagonists directed against the human tumor susceptibility gene 101 (Tsg101) are shown as examples. Three steps are involved: a) the design and synthesis of aminooxy platforms; b) tethering with aldehydes to form oxime-based linkages with sufficient purity; and c) direct in vitro biological evaluation of oxime products without purification. Each coupling reaction is a) performed in capped microtubes at room temperature; b) diluted for inhibitory evaluation and c) screened with targets in microplates to provide IC50 or Kd values. The synthesis of the aminooxy platforms takes 3–5 days; tethering with the aldehydes takes 24 h; and inhibition assay of enzymes and protein-protein interactions (PPIs) takes 30 min and 2 h respectively. PMID:22422315
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Statins inhibit blastocyst formation by preventing geranylgeranylation
Alarcon, Vernadeth B.; Marikawa, Yusuke
2016-01-01
STUDY HYPOTHESIS Statins, inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase of the mevalonate pathway and prescription drugs that treat hypercholesterolemia, compromise preimplantation mouse development via modulation of HIPPO signaling. STUDY FINDING HMG-CoA reductase activity is required for trophectoderm specification, namely blastocyst cavity formation and Yes-associated protein (YAP) nuclear localization, through the production of isoprenoid geranylgeranyl pyrophosphate (GGPP) and the action of geranylgeranyl transferase. WHAT IS KNOWN ALREADY Previous studies have shown that treatment of mouse embryos with mevastatin prevents blastocyst formation, but how HMG-CoA reductase is involved in preimplantation development is unknown. HIPPO signaling regulates specification of the trophectoderm lineage of the mouse blastocyst by controlling the nuclear localization of YAP. In human cell lines, the mevalonate pathway regulates YAP to mediate self-renewal and survival through geranylgeranylation of RHO proteins. These studies suggest that in preimplantation development, statins may act through HIPPO pathway to interfere with trophectoderm specification and thereby inhibit blastocyst formation. STUDY DESIGN, SAMPLES/MATERIALS, METHODS Eight-cell stage (E2.5) mouse embryos were treated in hanging drop culture with chemical agents, namely statins (lovastatin, atorvastatin, cerivastatin and pravastatin), mevalonic acid (MVA), cholesterol, squalene, farnesyl pyrophosphate (FPP), geranylgeranyl pyrophosphate (GGPP), geranylgeranyltransferase inhibitor GGTI-298, RHO inhibitor I, and squalene synthase inhibitor YM-53601, up to the late blastocyst stage (E4.5). Efficiency of blastocyst formation was assessed based on gross morphology and the measurement of the cavity size using an image analysis software. Effects on cell lineages and HIPPO signaling were analyzed using immunohistochemistry with confocal microscopy based on the expression patterns of the
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Tissue Inhibitor of Metalloproteinase-2 Suppresses Collagen Synthesis in Cultured Keloid Fibroblasts
Dohi, Teruyuki; Aoki, Masayo; Ogawa, Rei; Akaishi, Satoshi; Shimada, Takashi; Okada, Takashi; Hyakusoku, Hiko
2015-01-01
Background: Keloids are defined as a kind of dermal fibroproliferative disorder resulting from the accumulation of collagen. In the remodeling of extracellular matrix, the balance between matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) is as critical as the proper production of extracellular matrix. We investigate the role of TIMPs and MMPs in the pathogenesis of keloids and examine the therapeutic potential of TIMP-2. Methods: The expression of TIMPs and MMPs in most inflamed parts of cultured keloid fibroblasts (KFs) and peripheral normal skin fibroblasts (PNFs) in the same individuals and the reactivity of KFs to cyclic mechanical stretch were analyzed by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay (n = 7). To evaluate the effect of treating KFs with TIMP-2, collagen synthesis was investigated by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay, and microscopic analysis was used to examine the treatment effects of TIMP-2 on ex vivo cultures of keloid tissue (n = 6). Results: TIMP-2 was downregulated in cultured KFs compared with PNFs in the same individuals, and the reduction in TIMP-2 was exacerbated by cyclic mechanical stretch. Administration of TIMP-2 (200 or 300 ng/mL) significantly suppressed expression of Col1A2 and Col3A1 mRNA and collagen type I protein in KFs. TIMP-2 also significantly reduced the skin dermal and collagen bundle thickness in ex vivo cultures of keloid tissue. Conclusion: These results indicated that downregulation of TIMP-2 in KFs is a crucial event in the pathogenesis of keloids, and the TIMP-2 would be a promising candidate for the treatment of keloids. PMID:26495233
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Maheshwari, Neelesh; Karthikeyan, Chandrabose; Bhadada, Shraddha V; Sahi, Chandan; Verma, Amit K; Hari Narayana Moorthy, N S; Trivedi, Piyush
2018-06-08
Described herein is the synthesis and biological evaluation of a series of non-carboxylic inhibitors of Protein Tyrosine Phosphatase 1B designed using bioisosteric replacement strategy. Six N-(3-(1H-tetrazol-5-yl)phenyl)acetamide derivatives designed employing the aforementioned strategy were synthesized and screened for PTP1B inhibitory activity. Among the synthesized compounds, compound NM-03 exhibited the most potent inhibitory activity with IC 50 value of 4.48 µM. Docking studies with NM-03 revealed the key interactions with desired amino acids in the binding site of PTP1B. Furthermore, compound NM-03 also elicited good in vivo activity. Taken together, the results of this study establish N-(3-(1H-tetrazole-5-yl)phenyl)-2-(benzo[d]oxazol-2-ylthio)acetamide (NM-03) as a valuable lead molecule with great potential for PTP1B inhibitor development targeting diabetes. Copyright © 2018 Elsevier Inc. All rights reserved.
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Singh, Samsher; Kalia, Nitin P; Joshi, Prashant; Kumar, Ajay; Sharma, Parduman R; Kumar, Ashok; Bharate, Sandip B; Khan, Inshad A
2017-01-01
This study elucidated the role of boeravinone B, a NorA multidrug efflux pump inhibitor, in biofilm inhibition. The effects of boeravinone B plus ciprofloxacin, a NorA substrate, were evaluated in NorA-overexpressing, wild-type, and knocked-out Staphylococcus aureus (SA-1199B, SA-1199, and SA-K1758, respectively). The mechanism of action was confirmed using the ethidium bromide accumulation and efflux assay. The role of boeravinone B as a human P -glycoprotein ( P -gp) inhibitor was examined in the LS-180 (colon cancer) cell line. Moreover, its role in the inhibition of biofilm formation and intracellular invasion of S. aureus in macrophages was studied. Boeravinone B reduced the minimum inhibitory concentration (MIC) of ciprofloxacin against S. aureus and its methicillin-resistant strains; the effect was stronger in SA-1199B. Furthermore, time-kill kinetics revealed that boeravinone B plus ciprofloxacin, at subinhibitory concentration (0.25 × MIC), is as equipotent as that at the MIC level. This combination also had a reduced mutation prevention concentration. Boeravinone B reduced the efflux of ethidium bromide and increased the accumulation, thus strengthening the role as a NorA inhibitor. Biofilm formation was reduced by four-eightfold of the minimal biofilm inhibitory concentration of ciprofloxacin, effectively preventing bacterial entry into macrophages. Boeravinone B effectively inhibited P -gp with half maximal inhibitory concentration (IC 50 ) of 64.85 μM. The study concluded that boeravinone B not only inhibits the NorA-mediated efflux of fluoroquinolones but also considerably inhibits the biofilm formation of S. aureus. Its P -gp inhibition activity demonstrates its potential as a bioavailability and bioefficacy enhancer.
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Singh, Samsher; Kalia, Nitin P.; Joshi, Prashant; Kumar, Ajay; Sharma, Parduman R.; Kumar, Ashok; Bharate, Sandip B.; Khan, Inshad A.
2017-01-01
This study elucidated the role of boeravinone B, a NorA multidrug efflux pump inhibitor, in biofilm inhibition. The effects of boeravinone B plus ciprofloxacin, a NorA substrate, were evaluated in NorA-overexpressing, wild-type, and knocked-out Staphylococcus aureus (SA-1199B, SA-1199, and SA-K1758, respectively). The mechanism of action was confirmed using the ethidium bromide accumulation and efflux assay. The role of boeravinone B as a human P-glycoprotein (P-gp) inhibitor was examined in the LS-180 (colon cancer) cell line. Moreover, its role in the inhibition of biofilm formation and intracellular invasion of S. aureus in macrophages was studied. Boeravinone B reduced the minimum inhibitory concentration (MIC) of ciprofloxacin against S. aureus and its methicillin-resistant strains; the effect was stronger in SA-1199B. Furthermore, time–kill kinetics revealed that boeravinone B plus ciprofloxacin, at subinhibitory concentration (0.25 × MIC), is as equipotent as that at the MIC level. This combination also had a reduced mutation prevention concentration. Boeravinone B reduced the efflux of ethidium bromide and increased the accumulation, thus strengthening the role as a NorA inhibitor. Biofilm formation was reduced by four–eightfold of the minimal biofilm inhibitory concentration of ciprofloxacin, effectively preventing bacterial entry into macrophages. Boeravinone B effectively inhibited P-gp with half maximal inhibitory concentration (IC50) of 64.85 μM. The study concluded that boeravinone B not only inhibits the NorA-mediated efflux of fluoroquinolones but also considerably inhibits the biofilm formation of S. aureus. Its P-gp inhibition activity demonstrates its potential as a bioavailability and bioefficacy enhancer. PMID:29046665
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Novel Triazole-Quinoline Derivatives as Selective Dual Binding Site Acetylcholinesterase Inhibitors.
Mantoani, Susimaire P; Chierrito, Talita P C; Vilela, Adriana F L; Cardoso, Carmen L; Martínez, Ana; Carvalho, Ivone
2016-02-05
Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder worldwide. Currently, the only strategy for palliative treatment of AD is to inhibit acetylcholinesterase (AChE) in order to increase the concentration of acetylcholine in the synaptic cleft. Evidence indicates that AChE also interacts with the β-amyloid (Aβ) protein, acting as a chaperone and increasing the number and neurotoxicity of Aβ fibrils. It is known that AChE has two binding sites: the peripheral site, responsible for the interactions with Aβ, and the catalytic site, related with acetylcholine hydrolysis. In this work, we reported the synthesis and biological evaluation of a library of new tacrine-donepezil hybrids, as a potential dual binding site AChE inhibitor, containing a triazole-quinoline system. The synthesis of hybrids was performed in four steps using the click chemistry strategy. These compounds were evaluated as hAChE and hBChE inhibitors, and some derivatives showed IC50 values in the micro-molar range and were remarkably selective towards hAChE. Kinetic assays and molecular modeling studies confirm that these compounds block both catalytic and peripheral AChE sites. These results are quite interesting since the triazole-quinoline system is a new structural scaffold for AChE inhibitors. Furthermore, the synthetic approach is very efficient for the preparation of target compounds, allowing a further fruitful new chemical library optimization.
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NASA Technical Reports Server (NTRS)
Hochstein, L. I.
1992-01-01
Halobacterium saccharovorum synthesized ATP in response to a pH shift from 8 to 6.2. Synthesis was inhibited by carbonyl cyanide m-chloro-phenylhydrazone, dicyclohexylcarbodiimide, and azide. Nitrate, an inhibitor of the membrane-bound ATPase previously isolated from this organism, did not inhibit ATP synthesis. N-Ethymaleimide, which also inhibited this ATPase, stimulated the production of ATP. These observations suggested that H. saccharovorum synthesized and hydrolysed ATP using different enzymes and that the vacuolar-like ATPase activity previously described in H. saccharovorum was an ATPase whose function is yet to be identified.
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Synthesis and Biological Evaluation of Analogues of AKT (Protein Kinase B) Inhibitor-IV
Sun, Qi; Wu, Runzhi; Cai, Sutang; Lin, Yuan; Sellers, Llewlyn; Sakamoto, Kaori; He, Biao; Peterson, Blake R.
2011-01-01
Inhibitors of the PI3-kinase/AKT (protein kinase B) pathway are under investigation as anticancer and antiviral agents. The benzimidazole derivative AKT inhibitor-IV (ChemBridge 5233705) affects this pathway and exhibits potent anticancer and antiviral activity. To probe its biological activity, we synthesized AKT inhibitor-IV and 21 analogues using a novel six-step route based on ZrCl4-catalyzed cyclization of 1,2-arylenediamines with α,β-unsaturated aldehydes. We examined effects on viability of HeLa carcinoma cells, viability of normal human cells (NHBE), replication of recombinant parainfluenza virus 5 (PIV5) in HeLa cells, and replication of the intracellular bacterium Mycobacterium fortuitum in HeLa cells. Replacement of the benzimidazole N-ethyl substitutent of AKT inhibitor-IV with N-hexyl and N-dodecyl groups enhanced antiviral activity and cytotoxicity against the cancer cell line, but these compounds showed substantially lower toxicity (from 6-fold to >20-fold) against NHBE cells, and no effect on M. fortuitum, suggesting inhibition of one or more host protein(s) required for proliferation of cancer cells and PIV5. The key structural elements identified here may facilitate identification of targets of this highly biologically active scaffold. PMID:21319800
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Bourdel, E; Doulut, S; Jarretou, G; Labbe-Jullie, C; Fehrentz, J A; Doumbia, O; Kitabgi, P; Martinez, J
1996-08-01
Selective and mixed inhibitors of the three zinc metallopeptidases that degrade neurotensin (NT), e.g. endopeptidase 24-16 (EC 3.4.24.16), endopeptidase 24-11 (EC 3.4.24.11 or neutral endopeptidase, NEP) and endopeptidase 24-15 (EC 3.4.24.15), and leucine-aminopeptidase (type IV-S), that degrades the NT-related peptides, Neuromedin N (NN), are of great interest. On the structural basis of compound JMV 390-1 (N-[3-[(hydroxyamino)carbonyl]-1-oxo-2(R)-benzylpropyl]-L- isoleucyl-L-leucine), which was a full inhibitor of the major NT degrading enzymes, several hydroxamate inhibitors corresponding to the general formula HONHCO-CH2-CH(CH2-C6H5)CO-X-Y-OH (with X-Y = dipeptide) have been synthesized. Compound 7a (X-Y = Ile-Ala) was nearly 40-times more potent in inhibiting EC 24-16 than NEP and more than 800-times more potent than EC 24-15, with an IC50 (12 nM) almost equivalent to that of compound JMV 390-1. Therefore, this compound is an interesting selective inhibitor of EC 24-16, and should be an interesting probe to explore the physiological involvement of EC 24-16 in the metabolism of neurotensin.
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THE INTRACELLULAR SITE OF SYNTHESIS OF MITOCHONDRIAL RIBOSOMAL PROTEINS IN NEUROSPORA CRASSA
Lizardi, Paul M.; Luck, David J. L.
1972-01-01
The intracellular site of synthesis of mitochondrial ribosomal proteins (MRP) in Neurospora crassa has been investigated using three complementary approaches. (a) Mitochondrial protein synthesis in vitro: Tritium-labeled proteins made by isolated mitochondria were compared to 14C-labeled marker MRP by cofractionation in a two-step procedure involving isoelectric focusing and polyacrylamide gel electrophoresis. Examination of the electrophoretic profiles showed that essentially none of the peaks of in vitro product corresponded exactly to any of the MRP marker peaks. (b) Sensitivity of in vivo MRP synthesis to chloramphenicol: Cells were labeled with leucine-3H in the presence of chloramphenicol, mitochondrial ribosomal subunits were subsequently isolated, and their proteins fractionated by isoelectric focusing followed by gel electrophoresis. The labeling of every single MRP was found to be insensitive to chloramphenicol, a selective inhibitor of mitochondrial protein synthesis. (c) Sensitivity of in vivo MRP synthesis to anisomycin: We have found this antibiotic to be a good selective inhibitor of cytoplasmic protein synthesis in Neurospora. In the presence of anisomycin the labeling of virtually all MRP is inhibited to the same extent as the labeling of cytoplasmic ribosomal proteins. On the basis of these three types of studies we conclude that most if not all 53 structural proteins of mitochondrial ribosomal subunits in Neurospora are synthesized by cytoplasmic ribosomes. PMID:4261038
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[Pharmacogenic osteoporosis beyond cortisone. Proton pump inhibitors, glitazones and diuretics].
Kann, P H; Hadji, P; Bergmann, R S
2014-05-01
[corrected] There are many drugs which can cause osteoporosis or at least favor its initiation. The effect of hormones and drugs with antihormonal activity, such as glucocorticoids and aromatase inhibitors, on initiation of osteoporosis is well known. In addition, proton pump inhibitors, glitazones and diuretics also influence the formation of osteoporosis. The results of currently available studies on the correlation between proton pump inhibitors, glitazones and diuretics on formation of osteoporosis were evaluated and summarized. Proton pump inhibitors and glitazones increase the risk for osteoporotic fractures. Loop diuretics may slightly increase fracture risk, whereas thiazides were shown to be osteoprotective by reducing fracture probability on a relevant scale. Proton pump inhibitors should not be prescribed without serious consideration and then only as long as necessary. Alternatively, the administration of the less effective H2 antagonists should be considered when possible due to the reduction of acid secretion. Because the long-term intake of thiazides is associated with a clinically relevant reduction in the risk of fractures and they are economic and well-tolerated, prescription can be thoroughly recommended within the framework of differential diagnostic considerations in an appropriate clinical context. The briefly increased risk of falling immediately after starting diuretic therapy is the only point which needs to be considered.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Nagai, Rhoji; Murray, David B.; Metz, Thomas O.
2012-03-01
Advanced glycation or glycoxidation end-products (AGE) increase in tissue proteins with age, and their rate of accumulation is increased in diabetes, nephropathy and inflammatory diseases. AGE inhibitors include a range of compounds that are proposed to act by trapping carbonyl and dicarbonyl intermediates in AGE formation. However, some among the newer generation of AGE inhibitors lack reactive functional groups that would trap reaction intermediates, indicating an alternative mechanism of action. We propose that AGE inhibitors function primarily as chelators, inhibiting metal-catalyzed oxidation reactions. The AGE-inhibitory activity of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers is also consistent with their chelatingmore » activity. Finally, compounds described as AGE breakers, or their hydrolysis products, also have strong chelating activity, suggesting that these compounds also act through their chelating activity. We conclude that chelation is the common, and perhaps the primary, mechanism of action of AGE inhibitors and breakers, and that chronic, mild chelation therapy should prove useful in treatment of diabetes and age-related diseases characterized by oxidative stress, inflammation and increased chemical modification of tissue proteins by advanced glycoxidation and lipoxidation end-products.« less
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Chemoprevention of Prostate Cancer by Phenethyl Isothiocyanate
2007-03-01
AD cells were exposed to PEITC, protein synthesis inhibitor cycloheximide (CHX), or proteasome inhibitor MG-132 alone, or to the combination of...The results indicated that down-regulation of Sp1 may require protein synthesis for a proteasome activity, thereby enhancing Sp1 protein degradation...carcinogen N- methyl-N- nitrosourea (MNU) for the formation of prostate tumors. The experimental group of rats was provided with PEITC, to evaluate the
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Yang, Zhimin; Liu, Hui; Pan, Botao; He, Fengli; Pan, Zhengying
2018-05-21
As an important kinase in multiple signal transduction pathways, GSK-3β has been an attractive target for chemical probe discovery and drug development. Compared to numerous reversible inhibitors that have been developed, covalent inhibitors of GSK-3β are noticeably lacking. Here, we report the discovery of a series of covalent GSK-3β inhibitors by optimizing both non-covalent interactions and reactive groups. Among these covalent inhibitors, compound 38b with a mild α-fluoromethyl amide reactive group emerges as a selective and covalent inhibitor against GSK-3β, effectively inhibits the phosphorylation of glycogen synthase and tau protein, and increases β-catenin's levels in living cells. In addition, compound 38b is highly permeable and not a substrate of P-glycoprotein.
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Zhang, Yuanbao; Wei, Chao; Jiang, Wendi; Wang, Lei; Li, Churui; Wang, Yunyue; Dow, John Maxwell; Sun, Wenxian
2013-01-01
Bacterial leaf streak caused by Xanthomonas oryzae pv. oryzicola (Xoc) is one of the most important diseases in rice. However, little is known about the pathogenicity mechanisms of Xoc. Here we have investigated the function of three HD-GYP domain regulatory proteins in biofilm formation, the synthesis of virulence factors and virulence of Xoc. Deletion of rpfG resulted in altered production of extracellular polysaccharides (EPS), abolished virulence on rice and enhanced biofilm formation, but had little effect on the secretion of proteases and motility. In contrast, mutational analysis showed that the other two HD-GYP domain proteins had no effect on virulence factor synthesis and tested phenotypes. Mutation of rpfG led to up-regulation of the type III secretion system and altered expression of three putative glycosyltransferase genes gumD, pgaC and xagB, which are part of operons directing the synthesis of different extracellular polysaccharides. The pgaABCD and xagABCD operons were greatly up-regulated in the Xoc ΔrpfG mutant, whereas the expression of the gum genes was unaltered or slightly enhanced. The elevated biofilm formation of the Xoc ΔrpfG mutant was dramatically reduced upon deletion of gumD, xagA and xagB, but not when pgaA and pgaC were deleted. Interestingly, only the ΔgumD mutant, among these single gene mutants, exhibits multiple phenotype alterations including reduced biofilm and EPS production and attenuated virulence on rice. These data indicate that RpfG is a global regulator that controls biofilm formation, EPS production and bacterial virulence in Xoc and that both gumD- and xagB-dependent EPS contribute to biofilm formation under different conditions. PMID:23544067
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Adipocyte fatty acid binding protein 4 (FABP4) inhibitors. A comprehensive systematic review.
Floresta, Giuseppe; Pistarà, Venerando; Amata, Emanuele; Dichiara, Maria; Marrazzo, Agostino; Prezzavento, Orazio; Rescifina, Antonio
2017-09-29
Small molecule inhibitors of adipocyte fatty acid binding protein 4 (FABP4) have attracted interest following the recent publications of beneficial pharmacological effects of these compounds. FABP4 is predominantly expressed in macrophages and adipose tissue where it regulates fatty acids (FAs) storage and lipolysis and is an important mediator of inflammation. In the past years, hundreds FABP4 inhibitors have been synthesized for effective atherosclerosis and diabetes treatments, including derivatives of niacin, quinoxaline, aryl-quinoline, bicyclic pyridine, urea, aromatic compounds and other novel heterocyclic compounds. This review provides an overview of the synthesized and discovered molecules as adipocyte fatty acid binding protein 4 inhibitors (FABP4is) since the synthesis of the putative FABP4i, BMS309403, highlighting the interactions of the different classes of inhibitors with the targets. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
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Inhibitors for human glutaminyl cyclase by structure based design and bioisosteric replacement.
Buchholz, Mirko; Hamann, Antje; Aust, Susanne; Brandt, Wolfgang; Böhme, Livia; Hoffmann, Torsten; Schilling, Stephan; Demuth, Hans-Ulrich; Heiser, Ulrich
2009-11-26
The inhibition of human glutaminyl cyclase (hQC) has come into focus as a new potential approach for the treatment of Alzheimer's disease. The hallmark of this principle is the prevention of the formation of Abeta(3,11(pE)-40,42), as these Abeta-species were shown to be of elevated neurotoxicity and likely to act as a seeding core leading to an accelerated formation of Abeta-oligomers and fibrils. Starting from 1-(3-(1H-imidazol-1-yl)propyl)-3-(3,4-dimethoxyphenyl)thiourea, bioisosteric replacements led to the development of new classes of inhibitors. The optimization of the metal-binding group was achieved by homology modeling and afforded a first insight into the probable binding mode of the inhibitors in the hQC active site. The efficacy assessment of the hQC inhibitors was performed in cell culture, directly monitoring the inhibition of Abeta(3,11(pE)-40,42) formation.
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Recombinant factor concentrates may increase inhibitor development: a single centre cohort study.
Strauss, T; Lubetsky, A; Ravid, B; Bashari, D; Luboshitz, J; Lalezari, S; Misgav, M; Martinowitz, U; Kenet, G
2011-07-01
Recent reports have raised concerns regarding potential risk factors for inhibitor development. In Israel, all haemophilia patients (n = 479) are followed by the National Hemophilia Center. Most children are neonatally exposed to factor concentrate (due to circumcision performed at the age of 8 days). The impact of early exposure and recombinant FVIII products (rFVIII) administration (approved in Israel since 1996) upon inhibitor occurrence in our cohort of haemophilia A (HA) patients was analysed. Two hundred ninety-two consecutive paediatric cases with a first symptomatic onset of HA were enrolled and followed over a median time of 7 years [min-max: 9 months to 17 years]. Study endpoint was inhibitor development against factor VIII. In addition, the treatment regimens applied, i.e. bolus administration or 'continuous infusion' and the family history of inhibitor development were investigated. During the follow-up period 31/292 children (10.6%) developed high titre inhibitors. Inhibitors occurred in 14/43 (32.5%) HA patients neonatally exposed to rFVIII, as compared to 22/249 previously treated with Plasma Derived (PD) products (8.8%). The odds ratio for inhibitor formation in rFVIII treated HA patients was 3.43 (95% CI: 1.36-8.65). Transient inhibitor evolved among 2/43 paediatric HA patients, only among those treated with rFVIII. The risk of inhibitor detection significantly increased among HA children treated by continuous infusion (P = 0.025). Our experience shows that the risk of inhibitor formation may be increased by early exposure to recombinant concentrates. The multiple variables affecting inhibitor incidence deserve further attention by larger prospective studies. © 2011 Blackwell Publishing Ltd.
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Acute inhibition of neurosteroid estrogen synthesis suppresses status epilepticus in an animal model
Sato, Satoru M; Woolley, Catherine S
2016-01-01
Status epilepticus (SE) is a common neurological emergency for which new treatments are needed. In vitro studies suggest a novel approach to controlling seizures in SE: acute inhibition of estrogen synthesis in the brain. Here, we show in rats that systemic administration of an aromatase (estrogen synthase) inhibitor after seizure onset strongly suppresses both electrographic and behavioral seizures induced by kainic acid (KA). We found that KA-induced SE stimulates synthesis of estradiol (E2) in the hippocampus, a brain region commonly involved in seizures and where E2 is known to acutely promote neural activity. Hippocampal E2 levels were higher in rats experiencing more severe seizures. Consistent with a seizure-promoting effect of hippocampal estrogen synthesis, intra-hippocampal aromatase inhibition also suppressed seizures. These results reveal neurosteroid estrogen synthesis as a previously unknown factor in the escalation of seizures and suggest that acute administration of aromatase inhibitors may be an effective treatment for SE. DOI: http://dx.doi.org/10.7554/eLife.12917.001 PMID:27083045
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Gu, X.; Kim, Y. S.; Kaiser, R. I.; Mebel, A. M.; Liang, M. C.; Yung, Y. L.
2009-01-01
For the last four decades, the role of polyynes such as diacetylene (HCCCCH) and triacetylene (HCCCCCCH) in the chemical evolution of the atmosphere of Saturn's moon Titan has been a subject of vigorous research. These polyacetylenes are thought to serve as an UV radiation shield in planetary environments; thus, acting as prebiotic ozone, and are considered as important constituents of the visible haze layers on Titan. However, the underlying chemical processes that initiate the formation and control the growth of polyynes have been the least understood to date. Here, we present a combined experimental, theoretical, and modeling study on the synthesis of the polyyne triacetylene (HCCCCCCH) via the bimolecular gas phase reaction of the ethynyl radical (CCH) with diacetylene (HCCCCH). This elementary reaction is rapid, has no entrance barrier, and yields the triacetylene molecule via indirect scattering dynamics through complex formation in a single collision event. Photochemical models of Titan's atmosphere imply that triacetylene may serve as a building block to synthesize even more complex polyynes such as tetraacetylene (HCCCCCCCCH). PMID:19805262
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Gu, X; Kim, Y S; Kaiser, R I; Mebel, A M; Liang, M C; Yung, Y L
2009-09-22
For the last four decades, the role of polyynes such as diacetylene (HCCCCH) and triacetylene (HCCCCCCH) in the chemical evolution of the atmosphere of Saturn's moon Titan has been a subject of vigorous research. These polyacetylenes are thought to serve as an UV radiation shield in planetary environments; thus, acting as prebiotic ozone, and are considered as important constituents of the visible haze layers on Titan. However, the underlying chemical processes that initiate the formation and control the growth of polyynes have been the least understood to date. Here, we present a combined experimental, theoretical, and modeling study on the synthesis of the polyyne triacetylene (HCCCCCCH) via the bimolecular gas phase reaction of the ethynyl radical (CCH) with diacetylene (HCCCCH). This elementary reaction is rapid, has no entrance barrier, and yields the triacetylene molecule via indirect scattering dynamics through complex formation in a single collision event. Photochemical models of Titan's atmosphere imply that triacetylene may serve as a building block to synthesize even more complex polyynes such as tetraacetylene (HCCCCCCCCH).
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Inoue, Shinjiro; Okita, Yoichi; de Toledo, Andreia; Miyazaki, Hiroyuki; Hirano, Eiichi; Morinaga, Tetsuo
2015-01-01
We purified pyroglutamic acid from human placental extract and identified it as a potent stimulator of rat primary hepatocyte DNA synthesis. Pyroglutamic acid dose-dependently stimulated DNA synthesis, and this effect was inhibited by PD98059, a dual specificity mitogen-activated protein kinase kinase 1 (MAP2K1) inhibitor. Therefore, pyroglutamic acid stimulated DNA synthesis in rat primary hepatocytes via MAPK signaling.
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Hallstrand, Teal S; Lai, Ying; Hooper, Kathryn A; Oslund, Rob C; Altemeier, William A; Matute-Bello, Gustavo; Gelb, Michael H
2016-01-01
Phospholipase A2s mediate the rate-limiting step in the formation of eicosanoids such as cysteinyl leukotrienes (CysLTs). Group IVA cytosolic PLA2α (cPLA2α) is thought to be the dominant PLA2 in eosinophils; however, eosinophils also have secreted PLA2 (sPLA2) activity that has not been fully defined. To examine the expression of sPLA2 group X (sPLA2-X) in eosinophils, the participation of sPLA2-X in the formation of CysLTs, and the mechanism by which sPLA2-X initiates the synthesis of CysLTs in eosinophils. Peripheral blood eosinophils were obtained from volunteers with asthma and/or allergy. A rabbit polyclonal anti-sPLA2-X antibody identified sPLA2-X by Western blot. We used confocal microscopy to colocalize the sPLA2-X to intracellular structures. An inhibitor of sPLA2-X (ROC-0929) that does not inhibit other mammalian sPLA2s, as well as inhibitors of the mitogen-activated kinase cascade (MAPK) and cPLA2α, was used to examine the mechanism of N-formyl-methionyl-leucyl-phenylalanine (fMLP)-mediated formation of CysLT. Eosinophils express the mammalian sPLA2-X gene (PLA2G10). The sPLA2-X protein is located in the endoplasmic reticulum, golgi, and granules of eosinophils and moves to the granules and lipid bodies during fMLP-mediated activation. Selective sPLA2-X inhibition attenuated the fMLP-mediated release of arachidonic acid and CysLT formation by eosinophils. Inhibitors of p38, extracellular-signal-regulated kinases 1/2 (p44/42 MAPK), c-Jun N-terminal kinase, and cPLA2α also attenuated the fMLP-mediated formation of CysLT. The sPLA2-X inhibitor reduced the phosphorylation of p38 and extracellular-signal-regulated kinases 1/2 (p44/42 MAPK) as well as cPLA2α during cellular activation, indicating that sPLA2-X is involved in activating the MAPK cascade leading to the formation of CysLT via cPLA2α. We further demonstrate that sPLA2-X is activated before secretion from the cell during activation. Short-term priming with IL-13 and TNF/IL-1β increased the
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Ma, Kun; Kwon, Sun Hyung; Padmanabhan, Jagannath; Duscher, Dominik; Trotsyuk, Artem A; Dong, Yixiao; Inayathullah, Mohammed; Rajadas, Jayakumar; Gurtner, Geoffrey C
2018-05-15
Formation of scars following wounding or trauma represents a significant healthcare burden costing the economy billions of dollars every year. Activation of focal adhesion kinase (FAK) has been shown to play a pivotal role in transducing mechanical signals to elicit fibrotic responses and scar formation during wound repair. We have previously shown that inhibition of FAK using local injections of a small molecule FAK inhibitor (FAKI) can attenuate scar development in a hypertrophic scar model. Clinical translation of FAKI therapy has been challenging, however, due to the lack of an effective drug delivery system for extensive burn injuries, blast injuries, and large excisional injuries. To address this issue, we have developed a pullulan collagen-based hydrogel to deliver FAKI to excisional and burn wounds in mice. Specifically, two distinct drug-laden hydrogels were developed for rapid or sustained release of FAKI for treatment of burn wounds and excisional wounds, respectively. Controlled delivery of FAKI via pullulan collagen hydrogels accelerated wound healing, reduced collagen deposition and activation of scar forming myofibroblasts in both wound healing models. Our study highlights a biomaterial-based drug delivery approach for wound and scar management that has significant translational implications. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.
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Boyle, N A; Talesa, V; Giovannini, E; Rosi, G; Norton, S J
1997-09-12
Fourteen alkyl and aryl thiocarbonate derivatives of choline were synthesized and studied as potential inhibitors of acetylcholinesterase (AChE). Twelve of the compounds inhibited AChEs derived from calf forebrain, human red blood cells, and octopus brain ranging from low to moderately high inhibition potency. The concentration of each inhibitory compound giving 50% inhibition of enzyme activity (IC50 values, which ranged from 1 x 10(-2) to 8 x 10(-7) M) was determined and is reported; inhibitor constants (Ki values) for the most inhibitory compounds, (1-pentylthiocarbonyl)choline chloride and (1-heptylthiocarbonyl)choline chloride, were calculated from kinetic data and are also reported. The inhibitors are competitive with substrate, and they are not hydrolyzed by the AChE activities. Certain of these new compounds may provide direction for the development of new drugs that have anticholinesterase activity and may be used for the treatment of Alzheimer's disease.
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Studies on the Role of RNA Synthesis in Auxin Induction of Cell Enlargement 1
Nooden, Larry D.
1968-01-01
Selective inhibitors were used to study the connection between nucleic acid synthesis and indoleacetic acid (IAA) induction of cell enlargement. Actinomycin D (act D) and azaguanine (azaG) almost completely inhibit IAA-induced growth in aged artichoke tuber disks when they are added simultaneously with IAA. In contrast, when they are added 24 hours after the hormone, these inhibitors have little or no effect on the induced growth which continues for 48 hours or more with little or no inhibition. Inhibitors of protein synthesis still stop growth when applied 24 hours after the IAA, thus protein synthesis and presumably supporting metabolism are still essential. In corn coleoptile sections auxin-induced growth did not show any pronounced tendency to become less sensitive to act D as the IAA treatment progressed. Act D did not completely inhibit the response to IAA unless the sections were pretreated with act D for 6 hours. In contrast to act D, cordycepin produced almost complete inhibition of IAA-induced growth when added with the IAA. Although IAA has a very large and very rapid stimulatory effect (within 10 min) on incorporation of 32P-orthophosphate into RNA in disks, it did not cause a detectable change in the base composition of the RNA synthesized. Furthermore, the promotive effect could be accounted for through increased uptake of the 32P. That much of the RNA synthesis in these tissues is not necessary for auxin action is indicated by the results with fluorouracil (FU). FU strongly inhibits RNA synthesis, probably acting preferentially on ribosomal RNA synthesis, without inhibiting auxin-induced growth in the disks or coleoptile sections. FU also strongly inhibited respiration in auxin-treated disks indicating that the large promotion of respiration by auxin likewise may not be entirely necessary for growth. At least in the artichoke disks, RNA synthesis is required for auxin induction of cell enlargement and not for cell enlargement itself. The possible
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Identification of Small Molecule Inhibitors of Phosphatidylinositol 3-Kinase and Autophagy*
Farkas, Thomas; Daugaard, Mads; Jäättelä, Marja
2011-01-01
Macroautophagy (hereafter autophagy) is a lysosomal catabolic pathway that controls cellular homeostasis and survival. It has recently emerged as an attractive target for the treatment of a variety of degenerative diseases and cancer. The targeting of autophagy has, however, been hampered by the lack of specific small molecule inhibitors. Thus, we screened two small molecule kinase inhibitor libraries for inhibitors of rapamycin-induced autophagic flux. The three most potent inhibitors identified conferred profound inhibition of autophagic flux by inhibiting the formation of autophagosomes. Notably, the autophagy inhibitory effects of all three compounds were independent of their established kinase targets, i.e. ataxia telangiectasia mutated for KU55933, protein kinase C for Gö6976, and Janus kinase 3 for Jak3 inhibitor VI. Instead, we identified phosphatidylinositol 3-kinase (PtdIns3K) as a direct target of KU55933 and Gö6976. Importantly, and in contrast to the currently available inhibitors of autophagosome formation (e.g. 3-methyladenine), none of the three compounds inhibited the cell survival promoting class I phosphoinositide 3-kinase-Akt signaling at the concentrations required for effective autophagy inhibition. Accordingly, they proved to be valuable tools for investigations of autophagy-associated cell death and survival. Employing KU55399, we demonstrated that autophagy protects amino acid-starved cells against both apoptosis and necroptosis. Taken together, our data introduce new possibilities for the experimental study of autophagy and can form a basis for the development of clinically relevant autophagy inhibitors. PMID:21930714
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Maga, Giovanni; Radi, Marco; Gerard, Marie-Aline; Botta, Maurizio; Ennifar, Eric
2010-01-01
HIV-1 reverse transcriptase (RT) inhibitors currently used in antiretroviral therapy can be divided into two classes: (i) nucleoside analog RT inhibitors (NRTIs), which compete with natural nucleoside substrates and act as terminators of proviral DNA synthesis, and (ii) non-nucleoside RT inhibitors (NNRTIs), which bind to a hydrophobic pocket close to the RT active site. In spite of the efficiency of NRTIs and NNRTIs, the rapid emergence of multidrug-resistant mutations requires the development of new RT inhibitors with an alternative mechanism of action. Recently, several studies reported the discovery of novel non-nucleoside inhibitors with a distinct mechanism of action. Unlike classical NNRTIs, they compete with the nucleotide substrate, thus forming a new class of RT inhibitors: nucleotide-competing RT inhibitors (NcRTIs). In this review, we discuss current progress in the understanding of the peculiar behavior of these compounds. PMID:21994659
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Chen, Yan; Sit, Sing-Yuen; Chen, Jie; Swidorski, Jacob J; Liu, Zheng; Sin, Ny; Venables, Brian L; Parker, Dawn D; Nowicka-Sans, Beata; Lin, Zeyu; Li, Zhufang; Terry, Brian J; Protack, Tricia; Rahematpura, Sandhya; Hanumegowda, Umesh; Jenkins, Susan; Krystal, Mark; Dicker, Ira D; Meanwell, Nicholas A; Regueiro-Ren, Alicia
2018-05-15
The design and synthesis of a series of C28 amine-based betulinic acid derivatives as HIV-1 maturation inhibitors is described. This series represents a continuation of efforts following on from previous studies of C-3 benzoic acid-substituted betulinic acid derivatives as HIV-1 maturation inhibitors (MIs) that were explored in the context of C-28 amide substituents. Compared to the C-28 amide series, the C-28 amine derivatives exhibited further improvements in HIV-1 inhibitory activity toward polymorphisms in the Gag polyprotein as well as improved activity in the presence of human serum. However, plasma exposure of basic amines following oral administration to rats was generally low, leading to a focus on moderating the basicity of the amine moiety distal from the triterpene core. The thiomorpholine dioxide (TMD) 20 emerged from this study as a compound with the optimal antiviral activity and an acceptable pharmacokinetic profile in the C-28 amine series. Compared to the C-28 amide 3, 20 offers a 2- to 4-fold improvement in potency towards the screening viruses, exhibits low shifts in the EC 50 values toward the V370A and ΔV370 viruses in the presence of human serum or human serum albumin, and demonstrates improved potency towards the polymorphic T371A and V362I virus variants. Copyright © 2018 Elsevier Ltd. All rights reserved.
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NASA Astrophysics Data System (ADS)
Pautus, Stéphane; Alami, Mouad; Adam, Fréderic; Bernadat, Guillaume; Lawrence, Daniel A.; de Carvalho, Allan; Ferry, Gilles; Rupin, Alain; Hamze, Abdallah; Champy, Pierre; Bonneau, Natacha; Gloanec, Philippe; Peglion, Jean-Louis; Brion, Jean-Daniel; Bianchini, Elsa P.; Borgel, Delphine
2016-11-01
Plasminogen activator inhibitor-1 (PAI-1) is the main inhibitor of the tissue type and urokinase type plasminogen activators. High levels of PAI-1 are correlated with an increased risk of thrombotic events and several other pathologies. Despite several compounds with in vitro activity being developed, none of them are currently in clinical use. In this study, we evaluated a novel PAI-1 inhibitor, annonacinone, a natural product from the Annonaceous acetogenins group. Annonacinone was identified in a chromogenic screening assay and was more potent than tiplaxtinin. Annonacinone showed high potency ex vivo on thromboelastography and was able to potentiate the thrombolytic effect of tPA in vivo in a murine model. SDS-PAGE showed that annonacinone inhibited formation of PAI-1/tPA complex via enhancement of the substrate pathway. Mutagenesis and molecular dynamics allowed us to identify annonacinone binding site close to helix D and E and β-sheets 2A.
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The effect of ethionine on ribonucleic acid synthesis in rat liver.
Swann, P F
1975-01-01
1. By 1h after administration of ethionine to the female rat the appearance of newly synthesized 18SrRNA in the cytoplasm is completely inhibited. This is not caused by inhibition of RNA synthesis, for the synthesis of the large ribosomal precursor RNA (45S) and of tRNA continues. Cleavage of 45S RNA to 32S RNA also occurs, but there was no evidence for the accumulation of mature or immature rRNA in the nucleus. 2. The effect of ethionine on the maturation of rRNA was not mimicked by an inhibitor of protein synthesis (cycloheximide) or an inhibitor of polyamine synthesis [methylglyoxal bis(guanylhydrazone)]. 3. Unlike the ethionine-induced inhibition of protein synthesis, this effect was not prevented by concurrent administration of inosine. A similar effect could be induced in HeLa cells by incubation for 1h in a medium lacking methionine. The ATP concentration in these cells was normal. From these two observations it was concluded that the effect of etionine on rRNA maturation is not caused by an ethionine-induced lack of ATP. It is suggested that ethionine, by lowering the hepatic concentration of S-adenosylmethionine, prevents methylation of the ribosomal precursor. The methylation is essential for the correct maturation of the molecule; without methylation complete degradation occurs. PMID:1212195
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Struvite scale formation and control.
Parsons, S A; Doyle, J D
2004-01-01
Struvite scale formation is a major operational issue at both conventional and biological nutrient removal wastewater treatment plants. Factors affecting the formation of struvite scales were investigated including supersaturation, pH and pipe material and roughness. A range of control methods have been investigated including low fouling materials, pH control, inhibitor and chemical dosing. Control methods exist to reduce scale formation although each has its advantages and disadvantages.
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Binding of ACE-inhibitors to in vitro and patient-derived amyloid-β fibril models.
Bhavaraju, Manikanthan; Phillips, Malachi; Bowman, Deborah; Aceves-Hernandez, Juan M; Hansmann, Ulrich H E
2016-01-07
Currently, no drugs exist that can prevent or reverse Alzheimer's disease, a neurodegenerative disease associated with the presence, in the brain, of plaques that are composed of β-amyloid (Aβ) peptides. Recent studies suggest that angiotensin-converting enzyme (ACE) inhibitors, a set of drugs used to treat hypertension, may inhibit amyloid formation in vitro. In the present study, we investigate through computer simulations the binding of ACE inhibitors to patient-derived Aβ fibrils and contrast it with that of ACE inhibitors binding to in vitro generated fibrils. The binding affinities of the ACE inhibitors are compared with that of Congo red, a dye that is used to identify amyloid structures and that is known to be a weak inhibitor of Aβ aggregation. We find that ACE inhibitors have a lower binding affinity to the patient-derived fibrils than to in vitro generated ones. For patient-derived fibrils, their binding affinities are even lower than that of Congo red. Our observations raise doubts on the hypothesis that these drugs inhibit fibril formation in Alzheimer patients by interacting directly with the amyloids.
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Structural studies of a bifunctional inhibitor of neprilysin and DPP-IV.
Oefner, Christian; Pierau, Sabine; Schulz, Henk; Dale, Glenn E
2007-09-01
Neutral endopeptidase (NEP) is the major enzyme involved in the metabolic inactivation of a number of bioactive peptides including the enkephalins, substance P, endothelin, bradykinin and atrial natriuretic factor, as well as the incretin hormone glucagon-like peptide 1 (GLP-1), which is a potent stimulator of insulin secretion. The activity of GLP-1 is also rapidly abolished by the serine protease dipeptidyl peptidase IV (DPP-IV), which led to an elevated interest in inhibitors of this enzyme for the treatment of type II diabetes. A dual NEP/DPP-IV inhibitor concept is proposed, offering an alternative strategy for the treatment of type 2 diabetes. Here, the synthesis and crystal structures of the soluble extracellular domain of human NEP (residues 52-749) complexed with the NEP, competitive and potent dual NEP/DPP-IV inhibitor MCB3937 are described.
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Mayr, Christian; Wagner, Andrej; Loeffelberger, Magdalena; Bruckner, Daniela; Jakab, Martin; Berr, Frieder; Di Fazio, Pietro; Ocker, Matthias; Neureiter, Daniel; Pichler, Martin; Kiesslich, Tobias
2016-01-01
BMI1 is a core component of the polycomb repressive complex 1 (PRC1) and is up-regulated in biliary tract cancer (BTC), contributing to aggressive clinical features. In this study we investigated the cytotoxic effects of PTC-209, a recently developed inhibitor of BMI1, in BTC cells. PTC-209 reduced overall viability in BTC cell lines in a dose-dependent fashion (0.04 - 20 μM). Treatment with PTC-209 led to slightly enhanced caspase activity and stop of cell proliferation. Cell cycle analysis revealed that PTC-209 caused cell cycle arrest at the G1/S checkpoint. A comprehensive investigation of expression changes of cell cycle-related genes showed that PTC-209 caused significant down-regulation of cell cycle-promoting genes as well as of genes that contribute to DNA synthesis initiation and DNA repair, respectively. This was accompanied by significantly elevated mRNA levels of cell cycle inhibitors. In addition, PTC-209 reduced sphere formation and, in a cell line-dependent manner, aldehyde dehydrogease-1 positive cells. We conclude that PTC-209 might be a promising drug for future in vitro and in vivo studies in BTC. PMID:26623561
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Liu, Gai; Gaines, Jennifer C; Robbins, Kevin J; Lazo, Noel D
2012-10-11
The self-assembly of amyloid proteins into β-sheet rich assemblies is associated with human amyloidoses including Alzheimer's disease, Parkinson's disease, and type 2 diabetes. An attractive therapeutic strategy therefore is to develop small molecules that would inhibit protein self-assembly. Natural polyphenols are potential inhibitors of β-sheet formation. How these compounds affect the kinetics of self-assembly studied by thioflavin T (ThT) fluorescence is not understood primarily because their presence interferes with ThT fluorescence. Here, we show that by plotting peak intensities from nuclear magnetic resonance (NMR) against incubation time, kinetic profiles in the presence of the polyphenol can be obtained from which kinetic parameters of self-assembly can be easily determined. In applying this technique to the self-assembly of the islet amyloid polypeptide in the presence of curcumin, a biphenolic compound found in turmeric, we show that the kinetic profile is atypical in that it shows a prenucleation period during which there is no observable decrease in NMR peak intensities.
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Dhar, T G Murali; Watterson, Scott H; Chen, Ping; Shen, Zhongqi; Gu, Henry H; Norris, Derek; Carlsen, Marianne; Haslow, Kristin D; Pitts, William J; Guo, Junqing; Chorba, John; Fleener, Catherine A; Rouleau, Katherine A; Townsend, Robert; Hollenbaugh, Diane; Iwanowicz, Edwin J
2003-02-10
The synthesis and the structure-activity relationships (SAR) of analogues derived from the introduction of basic residues on ring D of quinolone-based inhibitors of IMPDH are described. This led to the identification of compound 27 as a potent inhibitor of IMPDH with significantly improved aqueous solubility over the lead compound 1.
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Functional screening of selective mitochondrial inhibitors of Plasmodium.
Gomez-Lorenzo, Maria G; Rodríguez-Alejandre, Ane; Moliner-Cubel, Sonia; Martínez-Hoyos, María; Bahamontes-Rosa, Noemí; Gonzalez Del Rio, Rubén; Ródenas, Carolina; Fuente, Jesús de la; Lavandera, Jose Luis; García-Bustos, Jose F; Mendoza-Losana, Alfonso
2018-05-09
Phenotypic screening has produced most of the new chemical entities currently in clinical development for malaria, plus many lead compounds active against Plasmodium falciparum asexual stages. However, lack of knowledge about the mode of action of these compounds delays and may even hamper their future development. Identifying the mode of action of the inhibitors greatly helps to prioritise compounds for further development as novel antimalarials. Here we describe a whole-cell method to detect inhibitors of the mitochondrial electron transport chain, using oxygen consumption as high throughput readout in 384-well plate format. The usefulness of the method has been confirmed with the Tres Cantos Antimalarial Compound Set (TCAMS). The assay identified 124 respiratory inhibitors in TCAMS, seven of which were novel anti-plasmodial chemical structures never before described as mitochondrial inhibitors. Copyright © 2018. Published by Elsevier Ltd.
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Pettinato, Giuseppe; Vanden Berg-Foels, Wendy S; Zhang, Ning; Wen, Xuejun
2014-01-01
We report a technology to form human embryoid bodies (hEBs) from singularized human embryonic stem cells (hESCs) without the use of the p160 rho-associated coiled-coil kinase inhibitor (ROCKi) or centrifugation (spin). hEB formation was tested under four conditions: +ROCKi/+spin, +ROCKi/-spin, -ROCKi/+spin, and -ROCKi/-spin. Cell suspensions of BG01V/hOG and H9 hESC lines were pipetted into non-adherent hydrogel substrates containing defined microwell arrays. hEBs of consistent size and spherical geometry can be formed in each of the four conditions, including the -ROCKi/-spin condition. The hEBs formed under the -ROCKi/-spin condition differentiated to develop the three embryonic germ layers and tissues derived from each of the germ layers. This simplified hEB production technique offers homogeneity in hEB size and shape to support synchronous differentiation, elimination of the ROCKi xeno-factor and rate-limiting centrifugation treatment, and low-cost scalability, which will directly support automated, large-scale production of hEBs and hESC-derived cells needed for clinical, research, or therapeutic applications.
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Design, synthesis and optimization of bis-amide derivatives as CSF1R inhibitors.
Ramachandran, Sreekanth A; Jadhavar, Pradeep S; Miglani, Sandeep K; Singh, Manvendra P; Kalane, Deepak P; Agarwal, Anil K; Sathe, Balaji D; Mukherjee, Kakoli; Gupta, Ashu; Haldar, Srijan; Raja, Mohd; Singh, Siddhartha; Pham, Son M; Chakravarty, Sarvajit; Quinn, Kevin; Belmar, Sebastian; Alfaro, Ivan E; Higgs, Christopher; Bernales, Sebastian; Herrera, Francisco J; Rai, Roopa
2017-05-15
Signaling via the receptor tyrosine kinase CSF1R is thought to play an important role in recruitment and differentiation of tumor-associated macrophages (TAMs). TAMs play pro-tumorigenic roles, including the suppression of anti-tumor immune response, promotion of angiogenesis and tumor cell metastasis. Because of the role of this signaling pathway in the tumor microenvironment, several small molecule CSF1R kinase inhibitors are undergoing clinical evaluation for cancer therapy, either as a single agent or in combination with other cancer therapies, including immune checkpoint inhibitors. Herein we describe our lead optimization effort that resulted in the identification of a potent, cellular active and orally bioavailable bis-amide CSF1R inhibitor. Docking and biochemical analysis allowed the removal of a metabolically labile and poorly permeable methyl piperazine group from an early lead compound. Optimization led to improved metabolic stability and Caco2 permeability, which in turn resulted in good oral bioavailability in mice. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Hameed, Abdul; Khan, Khalid Mohammed; Zehra, Syeda Tazeen; Ahmed, Ramasa; Shafiq, Zahid; Bakht, Syeda Mahwish; Yaqub, Muhammad; Hussain, Mazhar; de la Vega de León, Antonio; Furtmann, Norbert; Bajorath, Jürgen; Shad, Hazoor Ahmad; Tahir, Muhammad Nawaz; Iqbal, Jamshed
2015-08-01
Urease is an important enzyme which breaks urea into ammonia and carbon dioxide during metabolic processes. However, an elevated activity of urease causes various complications of clinical importance. The inhibition of urease activity with small molecules as inhibitors is an effective strategy for therapeutic intervention. Herein, we have synthesized a series of 19 benzofurane linked N-phenyl semithiocarbazones (3a-3s). All the compounds were screened for enzyme inhibitor activity against Jack bean urease. The synthesized N-phenyl thiosemicarbazones had varying activity levels with IC50 values between 0.077 ± 0.001 and 24.04 ± 0.14 μM compared to standard inhibitor, thiourea (IC50 = 21 ± 0.11 μM). The activities of these compounds may be due to their close resemblance of thiourea. A docking study with Jack bean urease (PDB ID: 4H9M) revealed possible binding modes of N-phenyl thiosemicarbazones. Copyright © 2015 Elsevier Inc. All rights reserved.
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Design, synthesis and biological evaluation of novel FGFR inhibitors bearing an indazole scaffold.
Liu, Jian; Peng, Xia; Dai, Yang; Zhang, Wei; Ren, Sumei; Ai, Jing; Geng, Meiyu; Li, Yingxia
2015-07-28
Fibroblast growth factor receptor (FGFR) is a potential target for cancer therapy. Based on the structure of AZD4547 and NVPBGJ-398, we designed novel 1H-indazol-3-amine scaffold derivatives by utilizing scaffold hopping and molecular hybridization strategies. Consequently, twenty-eight new compounds were synthesized and evaluated for their inhibitory activity against FGFR1. Compound 7n bearing a 6-(3-methoxyphenyl)-1H-indazol-3-amine scaffold was first identified as a potent FGFR1 inhibitor, with good enzymatic inhibition (IC50 = 15.0 nM) and modest cellular inhibition (IC50 = 642.1 nM). The crystal structure of 7n bound to FGFR1 was obtained, which might provide a new basis for potent inhibitor design. Further structural optimization revealed that compound 7r stood out as the most potent FGFR1 inhibitor with the best enzyme inhibitory (IC50 = 2.9 nM) and cellular activity (IC50 = 40.5 nM).
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Antitumor activity of a novel and orally available inhibitor of serine palmitoyltransferase
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yaguchi, Masahiro; Shibata, Sachio; Satomi, Yoshinori
Metabolic reprogramming is an essential hallmark of neoplasia. Therefore, targeting cancer metabolism, including lipid synthesis, has attracted much interest in recent years. Serine palmitoyltransferase (SPT) plays a key role in the initial and rate-limiting step of de novo sphingolipid biosynthesis, and inhibiting SPT activity prevents the proliferation of certain cancer cells. Here, we identified a novel and orally available SPT inhibitor, compound-2. Compound-2 showed an anti-proliferative effect in several cancer cell models, reducing the levels of the sphingolipids ceramide and sphingomyelin. In the presence of compound-2, exogenously added S1P partially compensated the intracellular sphingolipid levels through the salvage pathway bymore » partially rescuing compound-2-induced cytotoxicity. This suggested that the mechanism underlying the anti-proliferative effect of compound-2 involved the reduction of sphingolipid levels. Indeed, compound-2 promoted multinuclear formation with reduced endogenous sphingomyelin levels specifically in a compound-2-sensitive cell line, indicating that the effect was induced by sphingolipid reduction. Furthermore, compound-2 showed potent antitumor activity without causing significant body weight loss in the PL-21 acute myeloid leukemia mouse xenograft model. Therefore, SPT may be an attractive therapeutic anti-cancer drug target for which compound-2 may be a promising new drug. - Highlights: • We discovered compound-2, a novel and orally available SPT inhibitor. • Compound-2 was cytotoxic against PL-21 acute myeloid leukemia cells. • Compound-2 showed antitumor activity in the PL-21 mouse xenograft model.« less
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Clues on the Milky Way disc formation from population synthesis simulations
NASA Astrophysics Data System (ADS)
Robin, A. C.; Reylé, C.; Bienaymé, O.; Fernandez-Trincado, J. G.; Amôres, E. B.
2016-09-01
In recent years the stellar populations of the Milky Way have been investigated from large scale surveys in different ways, from pure star count analysis to detailed studies based on spectroscopic surveys. While in the former case the data can constrain the scale height and scale length thanks to completeness, they suffer from high correlation between these two values. On the other hand, spectroscopic surveys suffer from complex selection functions which hardly allow to derive accurate density distributions. The scale length in particular has been difficult to be constrained, resulting in discrepant values in the literature. Here, we investigate the thick disc characteristics by comparing model simulations with large scale data sets. The simulations are done from the population synthesis model of Besançon. We explore the parameters of the thick disc (shape, local density, age, metallicity) using a Monte Carlo Markov Chain method to constrain the model free parameters (Robin et al. 2014). Correlations between parameters are limited due to the vast spatial coverage of the used surveys (SDSS + 2MASS). We show that the thick disc was created during a long phase of formation, starting about 12 Gyr ago and finishing about 10 Gyr ago, during which gravitational contraction occurred, both vertically and radially. Moreover, in its early phase the thick disc was flaring in the outskirts. We conclude that the thick disc has been created prior to the thin disc during a gravitational collapse phase, slowed down by turbulence related to a high star formation rate, as explained for example in Bournaud et al. (2009) or Lehnert et al. (2009). Our result does not favor a formation from an initial thin disc thickened later by merger events or by secular evolution of the thin disc. We then study the in-plane distribution of stars in the thin disc from 2MASS and show that the thin disc scale length varies as a function of age, indicating an inside out formation. Moreover, we
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Heude, M; Chanet, R; Moustacchi, E
1975-04-01
The contribution of nuclear-directed protein synthesis in the repair of lethal and mitochondrial genetic damage after UV-irradiation of exponential and stationary phage haploid yeast cells was examined. This was carried out using cycloheximide (CH), a specific inhibitor of nuclear protein synthesis. It appears that nuclear protein synthesis is required for the increase in survival seen after the liquid holding of cells at both stages, as well as for the "petite" recovery seen after the liquid holding of exponential phase cells. The characteristic negative liquid holding effect observed for the UV induction of "petites" in stationary phase cells (increase of the frequency of "petites" during storage) remained following all the treatments which inhibited nuclear protein synthesis. However, the application of photoreactivating light following dark holding with cycloheximide indicates that some steps of the repair of both nuclear and mitochondrial damage are performed in the absence of a synthesis of proteins.
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White, R; Ram, S
1996-01-01
In the mesenteric microcirculation, inhibition of nitric oxide (NO) synthesis results in an inflammatory response through increased leukocyte adherence to the microvascular postcapillary venular endothelium. Recent studies have demonstrated that elevated concentrations of endogenous NO synthesis inhibitors are present in renal failure. How peritoneal dialysis solutions may affect leukocyte-endothelial interactions during inflammation induced by NO synthesis inhibition has been previously unknown. Using in vivo intravital microscopy of the rat mesenteric postcapillary venules, microvascular leukocyte adherence was quantitated during baseline conditions in which the mesentery was superfused with a buffer solution, followed by the superfusion of a NO synthesis inhibitor NG-nitro-L-ARGININE methyl ester (L-NAME) added to the buffer, followed by 4.25% Dianeal (4.25% D). When compared to baseline, L-NAME increased the mean number of adherent leukocytes by fivefold (2.2 +/- 0.9 vs 11.6 +/- 3.6 leukocytes/100 microns venule/10 min, p < 0.05), while 4.25% D quickly reversed the L-NAME-induced inflammatory response, returning the number of adherent leukocytes back to baseline values (11.6 +/- 3.6 vs 2.4 +/- 1.3 leukocytes/100 microns venule/ 10 min, p < 0.05). These results confirm that NO synthesis inhibition induces inflammation in mesenteric postcapillary venules. Superfusion of 4.25% D reverses leukocyte adhesion induced by NO synthesis inhibition. Thus, a standard peritoneal dialysis solution (4.25% D) reverses the leukocyte-adhesive effects of NO synthesis inhibition in the mesenteric microcirculation.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Krishna, M.; Generoso, W.M.
1977-11-01
Timing of development of naturally ovulated mouse eggs from sperm penetration to first cleavage, including that of DNA synthesis, was established. In an attempt to limit variability, partial synchronization of ovulation was accomplished by shortening the length of the dark period to five hours, and partial synchronization of sperm entry was attempted by mating the females soon after the ovulated eggs reached the ampulla and by limiting the period at which mating could occur to only 20 minutes. Evidence of sperm penetration (presence of one or more sperm in perivitelline space or inside the vitellus) was found beginning 1.75 hoursmore » after the end of the mating period. Pronuclei were formed three to four hours after sperm entry. Pronuclear DNA synthesis began about eight hours postmating, 3.25 to 4.5 hours after pronuclear formation, or about 6.25 to 8.5 hours after sperm entry; it was completed in almost all zygotes by 16 hours postmating. The first completed cleavage division was found 17 to 18 hours postmating, and almost all eggs had cleaved by 20 hours.« less
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Gibberellin–Abscisic Acid Balances during Arbuscular Mycorrhiza Formation in Tomato
Martín-Rodríguez, José A.; Huertas, Raúl; Ho-Plágaro, Tania; Ocampo, Juan A.; Turečková, Veronika; Tarkowská, Danuše; Ludwig-Müller, Jutta; García-Garrido, José M.
2016-01-01
Plant hormones have become appropriate candidates for driving functional plant mycorrhization programs, including the processes that regulate the formation of arbuscules in arbuscular mycorrhizal (AM) symbiosis. Here, we examine the role played by ABA/GA interactions regulating the formation of AM in tomato. We report differences in ABA and GA metabolism between control and mycorrhizal roots. Active synthesis and catabolism of ABA occur in AM roots. GAs level increases as a consequence of a symbiosis-induced mechanism that requires functional arbuscules which in turn is dependent on a functional ABA pathway. A negative interaction in their metabolism has been demonstrated. ABA attenuates GA-biosynthetic and increases GA-catabolic gene expression leading to a reduction in bioactive GAs. Vice versa, GA activated ABA catabolism mainly in mycorrhizal roots. The negative impact of GA3 on arbuscule abundance in wild-type plants is partially offset by treatment with ABA and the application of a GA biosynthesis inhibitor rescued the arbuscule abundance in the ABA-deficient sitiens mutant. These findings, coupled with the evidence that ABA application leads to reduce bioactive GA1, support the hypothesis that ABA could act modifying bioactive GA level to regulate AM. Taken together, our results suggest that these hormones perform essential functions and antagonize each other by oppositely regulating AM formation in tomato roots. PMID:27602046
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Sarfraz, Muhammad; Sultana, Nargis; Rashid, Umer; Akram, Muhammad Safwan; Sadiq, Abdul; Tariq, Muhammad Ilyas
2017-02-01
In search of potent inhibitors of cholinesterases, we have synthesized and evaluate a number of 2,3-dihydroquinazolin-4(1H)-one derivatives. The synthetic approach provided an efficient synthesis of the target molecules with excellent yield. All the tested compounds showed activity against both the enzymes in micromolar range. In many case, the inhibition of both enzymes are higher than or comparable to the standard drug galatamine. With the selectivity index of 2.3 for AChE, compound 5f can be considered as a potential lead compound with a feature of dual AChE/BChE inhibition with IC 50 =1.6±0.10μM (AChE) and 3.7±0.18μM (BChE). Binding modes of the synthesized compounds were explored by using GOLD (Genetic Optimization for Ligand Docking) suit v5.4.1. The computed binding modes of these compounds in the active site of AChE and BChE provide an insight into the mechanism of inhibition of these two enzyme. Copyright © 2017 Elsevier Inc. All rights reserved.
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Cheng, Chien-shan; Wang, Zhiyu; Chen, Jianping
2014-01-01
Molecular targeted therapy has been developed for cancer chemoprevention and treatment. Cancer cells process a fundamental change in its bioenergetic metabolism from normal cells on an altered lipid metabolism, also known as the de novo fatty acid synthesis, for sustaining their high proliferation rates. Fatty acid synthesis is now associated with clinically aggressive tumor behavior and tumor cell growth and has become a novel target pathway for chemotherapy development. Although the underlying mechanisms of the altered de novo fatty acid synthesis still remains unclear, recent progress has shown that by targeting Fatty acid synthase (FASN), a key enzyme that catalyzes the synthesis of endogenous long chain fatty acid could be a critical target for drug discovery. However, relatively few FASN inhibitors have been discovered. With the long history of clinical practices and numerous histological case study reports, traditional Chinese medicine enjoys an important role in seeking bioactive anticancer natural compounds. Herein, we will give an overall picture of the current progress of molecular targeted therapy in cancer fatty acid synthesis, describe the advances in the research on natural products-derived FASN inhibitors and their potential for enhancing our understanding of fatty acids in tumor biology, and may provide new therapeutic moieties for breast cancer patient care. PMID:24778702
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Treatment of Plants with Gaseous Ethylene and Gaseous Inhibitors of Ethylene Action.
Tucker, Mark L; Kim, Joonyup; Wen, Chi-Kuang
2017-01-01
The gaseous nature of ethylene affects not only its role in plant biology but also how you treat plants with the hormone. In many ways, it simplifies the treatment problem. Other hormones have to be made up in solution and applied to some part of the plant hoping the hormone will be taken up into the plant and translocated throughout the plant at the desired concentration. Because all plant cells are connected by an intercellular gas space the ethylene concentration you treat with is relatively quickly reached throughout the plant. In some instances, like mature fruit, treatment with ethylene initiates autocatalytic synthesis of ethylene. However, in most experiments, the exogenous ethylene concentration is saturating, usually >1 μL L -1 , and the synthesis of additional ethylene is inconsequential. Also facilitating ethylene research compared with other hormones is that there are inhibitors of ethylene action 1-MCP (1-methylcyclopropene) and 2,5-NBD (2,5-norbornadiene) that are also gases wherein you can achieve nearly 100% inhibition of ethylene action quickly and with few side effects. Inhibitors for other plant hormones are applied as a solution and their transport and concentration at the desired site is not always known and difficult to measure. Here, our focus is on how to treat plants and plant parts with the ethylene gas and the gaseous inhibitors of ethylene action.
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Hussein, H; Dulin, J; Smanik, L; Drost, W T; Russell, D; Wellman, M; Bertone, A
2017-08-01
Our investigations evaluated the effect of VEL-0230, a highly specific irreversible inhibitor of cathepsin K (CatK). The objectives of our study were to determine whether repeated dosing of a CatK inhibitor (CatKI) produced a desired inhibition of the bone resorption biomarker (CTX-1), and document the effect of repeated dosing on bone homeostasis, structure, and dynamics of bone resorption and formation in horses. Twelve young exercising horses were randomized in a prospective, controlled clinical trial and received 4 weekly doses of a CatKI or vehicle. Baseline and poststudy nuclear scintigraphy, blood sampling and analysis of plasma bone biomarkers (CTX-1 and osteocalcin), poststudy bone fluorescent labeling, and bone biopsy were performed. Bone specimens were further processed for microcomputed tomography and bone histomorphometry. Each dose of this CatKI transiently inhibited plasma CTX-1 (reflecting inhibition of bone collagen resorption) and increased bone plasma osteocalcin concentrations, with no detectable adverse effect on normal bone turnover in the face of exercise. Bone morphology, density, and formation rate were not different between control and treated group. Further investigation of CatK inhibition in abnormal bone turnover is required in animals with bone diseases. © 2016 John Wiley & Sons Ltd.
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[Cytotoxicity of chimera peptides incorporating sequences of cyclin kinases inhibitors].
Kharchenko, V P; Kulinich, V G; Lunin, V G; Filiasova, E I; Shishkin, A M; Sergeenko, O V; Riazanova, E M; Voronina, O L; Bozhenko, V K
2007-01-01
The study is concerned with proapoptotic properties of chimera peptides which incorporate sequences of inhibitors of cyclin kinases p161NK4a and p21CIP/WAF1 as well as internalized sequences (Antp and tat). Sequences of the p16 type appeared to be more cytotoxic than the p21 one. Cytotoxic effect proved dependent on orientation with respect to the C or N terminal point of a polypeptide chain rather than on chimera sequence extent. Although p16 endogenous synthesis did not influence chimera peptide levels, apoptosis did not take place in certain cellular lines. Due to the rather unsophisticated nature of such synthesis, it might be used in designing individually-tailored chemotherapeutic drugs.
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NASA Technical Reports Server (NTRS)
Peretyazhko, T. S.; Fox, A.; Sutter, B.; Niles, P. B.; Adams, M.; Morris, R. V.; Ming, D. W.
2016-01-01
Akaganeite (beta-FeOOH) is an Fe(III) (hydr)oxide with a tunnel structure usually occupied by chloride. Akaganeite has been recently discovered in a mudstone on the surface of Mars by the Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars (SAM) instruments onboard the Mars Science Laboratory (MSL) Curiosity Rover in Gale crater [1, 2]. Akaganeite was detected together with sulfate minerals [anhydrite (CaSO4) and basanite (2CaSO4·2H2O)] in the drilled Cumberland and John Clein mudstone samples at Yellowknife Bay [2]. Discovery of akaganeite and sulfates in the same samples suggests that sulfate ions could be present in aqueous solution during akaganeite formation. However, mechanism and aqueous environmental conditions of akaganeite formation (e.g., pH and range of sulfate concentration) in Yellowknife Bay remain unknown. The objective of our work was to perform synthesis of akaganeite without or with sulfate addition at variable pHs in order to constrain formation conditions of akaganeite in Yellowknife Bay, Gale crater on Mars.
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Ganellin, C R; Bishop, P B; Bambal, R B; Chan, S M; Law, J K; Marabout, B; Luthra, P M; Moore, A N; Peschard, O; Bourgeat, P; Rose, C; Vargas, F; Schwartz, J C
2000-02-24
The cholecystokinin-8 (CCK-8)-inactivating peptidase is a serine peptidase which has been shown to be a membrane-bound isoform of tripeptidyl peptidase II (EC 3.4.14.10). It cleaves the neurotransmitter CCK-8 sulfate at the Met-Gly bond to give Asp-Tyr(SO(3)H)-Met-OH + Gly-Trp-Met-Asp-Phe-NH(2). In seeking a reversible inhibitor of this peptidase, the enzymatic binding subsites were characterized using a fluorimetric assay based on the hydrolysis of the artificial substrate Ala-Ala-Phe-amidomethylcoumarin. A series of di- and tripeptides having various alkyl or aryl side chains was studied to determine the accessible volume for binding and to probe the potential for hydrophobic interactions. From this initial study the tripeptides Ile-Pro-Ile-OH (K(i) = 1 microM) and Ala-Pro-Ala-OH (K(i) = 3 microM) and dipeptide amide Val-Nvl-NHBu (K(i) = 3 microM) emerged as leads. Comparison of these structures led to the synthesis of Val-Pro-NHBu (K(i) = 0.57 microM) which served for later optimization in the design of butabindide, a potent reversible competitive and selective inhibitor of the CCK-8-inactivating peptidase. The strategy for this work is explicitly described since it illustrates a possible general approach for peptidase inhibitor design.
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Harris, Lawrence D; Harijan, Rajesh K; Ducati, Rodrigo G; Evans, Gary B; Hirsch, Brett M; Schramm, Vern L
2018-01-19
Phosphoribosyl transferases (PRTs) are essential in nucleotide synthesis and salvage, amino acid, and vitamin synthesis. Transition state analysis of several PRTs has demonstrated ribocation-like transition states with a partial positive charge residing on the pentose ring. Core chemistry for synthesis of transition state analogues related to the 5-phospho-α-d-ribosyl 1-pyrophosphate (PRPP) reactant of these enzymes could be developed by stereospecific placement of bis-phosphate groups on an iminoaltritol ring. Cationic character is provided by the imino group and the bis-phosphates anchor both the 1- and 5-phosphate binding sites. We provide a facile synthetic path to these molecules. Cyclic-nitrone redox methodology was applied to the stereocontrolled synthesis of three stereoisomers of a selectively monoprotected diol relevant to the synthesis of transition-state analogue inhibitors. These polyhydroxylated pyrrolidine natural product analogues were bis-phosphorylated to generate analogues of the ribocationic form of 5-phosphoribosyl 1-phosphate. A safe, high yielding synthesis of the key intermediate represents a new route to these transition state mimics. An enantiomeric pair of iminoaltritol bis-phosphates (L-DIAB and D-DIAB) was prepared and shown to display inhibition of Plasmodium falciparum orotate phosphoribosyltransferase and Saccharomyces cerevisiae adenine phosphoribosyltransferase (ScAPRT). Crystallographic inhibitor binding analysis of L- and D-DIAB bound to the catalytic sites of ScAPRT demonstrates accommodation of both enantiomers by altered ring geometry and bis-phosphate catalytic site contacts.
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Design, Synthesis, and Evaluation of Dihydrobenzo[cd]indole-6-sulfonamide as TNF-α Inhibitors.
Deng, Xiaobing; Zhang, Xiaoling; Tang, Bo; Liu, Hongbo; Shen, Qi; Liu, Ying; Lai, Luhua
2018-01-01
Tumor necrosis factor-α (TNF-α) plays a pivotal role in inflammatory response. Dysregulation of TNF can lead to a variety of disastrous pathological effects, including auto-inflammatory diseases. Antibodies that directly targeting TNF-α have been proven effective in suppressing symptoms of these disorders. Compared to protein drugs, small molecule drugs are normally orally available and less expensive. Till now, peptide and small molecule TNF-α inhibitors are still in the early stage of development, and much more efforts should be made. In a previously study, we reported a TNF-α inhibitor, EJMC-1 with modest activity. Here, we optimized this compound by shape screen and rational design. In the first round, we screened commercial compound library for EJMC-1 analogs based on shape similarity. Out of the 68 compounds tested, 20 compounds showed better binding affinity than EJMC-1 in the SPR competitive binding assay. These 20 compounds were tested in cell assay and the most potent compound was 2-oxo-N-phenyl-1,2-dihydrobenzo[ cd ]indole-6-sulfonamide ( S10 ) with an IC 50 of 14 μM, which was 2.2-fold stronger than EJMC-1 . Based on the docking analysis of S10 and EJMC-1 binding with TNF-α, in the second round, we designed S10 analogs, purchased seven of them, and synthesized seven new compounds. The best compound, 4e showed an IC 50 -value of 3 μM in cell assay, which was 14-fold stronger than EJMC-1 . 4e was among the most potent TNF-α organic compound inhibitors reported so far. Our study demonstrated that 2-oxo-N-phenyl-1,2-dihydrobenzo[ cd ]indole-6-sulfonamide analogs could be developed as potent TNF-α inhibitors. 4e can be further optimized for its activity and properties. Our study provides insights into designing small molecule inhibitors directly targeting TNF-α and for protein-protein interaction inhibitor design.
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Design, Synthesis, and Evaluation of Dihydrobenzo[cd]indole-6-sulfonamide as TNF-alpha Inhibitors
NASA Astrophysics Data System (ADS)
Deng, Xiaobing; Zhang, Xiaoling; Tang, Bo; Liu, Hongbo; Shen, Qi; Liu, Ying; Lai, Luhua
2018-04-01
Tumor necrosis factor-α (TNF-α) plays a pivotal role in inflammatory response. Dysregulation of TNF can lead to a variety of disastrous pathological effects, including auto-inflammatory diseases. Antibodies that directly targeting TNF-α have been proven effective in suppressing symptoms of these disorders. Compared to protein drugs, small molecule drugs are normally orally available and less expensive. Till now, peptide and small molecule TNF-α inhibitors are still in the early stage of development, and much more efforts should be made. In a previously study, we reported a TNF-α inhibitor, EJMC-1 with modest activity. Here, we optimized this compound by shape screen and rational design. In the first round, we screened commercial compound library for EJMC-1 analogs based on shape similarity. Out of the 68 compounds tested, 20 compounds showed better binding affinity than EJMC-1 in the SPR competitive binding assay. These 20 compounds were tested in cell assay and the most potent compound was 2-oxo-N-phenyl-1,2-dihydrobenzo[cd]indole-6-sulfonamide (S10) with an IC50 of 14 M, which was 2.2-fold stronger than EJMC-1. Based on the docking analysis of S10 and EJMC-1 binding with TNF-α, in the second round, we designed S10 analogues, purchased 7 of them and synthesized 7 new compounds. The best compound, 4e showed an IC50 value of 3 M in cell assay, which was 14-fold stronger than EJMC-1. 4e was among the most potent TNF-α organic compound inhibitors reported so far. Our study demonstrated that 2-oxo-N-phenyl-1,2-dihydrobenzo[cd]indole-6-sulfonamide analogues could be developed as potent TNF-α inhibitors. 4e can be further optimized for its activity and properties. Our study provides insights into designing small molecule inhibitors directly targeting TNF-α and for protein-protein interaction inhibitor design.
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Hideshima, Teru; Paranal, Ronald M.; Tang, Weiping; Greenberg, Edward; West, Nathan; Colling, Meaghan E.; Estiu, Guillermina; Mazitschek, Ralph; Perry, Jennifer A.; Ohguchi, Hiroto; Cottini, Francesca; Mimura, Naoya; Görgün, Güllü; Tai, Yu-Tzu; Richardson, Paul G.; Carrasco, Ruben D.; Wiest, Olaf; Schreiber, Stuart L.; Anderson, Kenneth C.; Bradner, James E.
2016-01-01
Multiple myeloma (MM) has proven clinically susceptible to modulation of pathways of protein homeostasis. Blockade of proteasomal degradation of polyubiquitinated misfolded proteins by the proteasome inhibitor bortezomib (BTZ) achieves responses and prolongs survival in MM, but long-term treatment with BTZ leads to drug-resistant relapse in most patients. In a proof-of-concept study, we previously demonstrated that blocking aggresomal breakdown of polyubiquitinated misfolded proteins with the histone deacetylase 6 (HDAC6) inhibitor tubacin enhances BTZ-induced cytotoxicity in MM cells in vitro. However, these foundational studies were limited by the pharmacologic liabilities of tubacin as a chemical probe with only in vitro utility. Emerging from a focused library synthesis, a potent, selective, and bioavailable HDAC6 inhibitor, WT161, was created to study the mechanism of action of HDAC6 inhibition in MM alone and in combination with BTZ. WT161 in combination with BTZ triggers significant accumulation of polyubiquitinated proteins and cell stress, followed by caspase activation and apoptosis. More importantly, this combination treatment was effective in BTZ-resistant cells and in the presence of bone marrow stromal cells, which have been shown to mediate MM cell drug resistance. The activity of WT161 was confirmed in our human MM cell xenograft mouse model and established the framework for clinical trials of the combination treatment to improve patient outcomes in MM. PMID:27799547
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Microarray-based screening of heat shock protein inhibitors.
Schax, Emilia; Walter, Johanna-Gabriela; Märzhäuser, Helene; Stahl, Frank; Scheper, Thomas; Agard, David A; Eichner, Simone; Kirschning, Andreas; Zeilinger, Carsten
2014-06-20
Based on the importance of heat shock proteins (HSPs) in diseases such as cancer, Alzheimer's disease or malaria, inhibitors of these chaperons are needed. Today's state-of-the-art techniques to identify HSP inhibitors are performed in microplate format, requiring large amounts of proteins and potential inhibitors. In contrast, we have developed a miniaturized protein microarray-based assay to identify novel inhibitors, allowing analysis with 300 pmol of protein. The assay is based on competitive binding of fluorescence-labeled ATP and potential inhibitors to the ATP-binding site of HSP. Therefore, the developed microarray enables the parallel analysis of different ATP-binding proteins on a single microarray. We have demonstrated the possibility of multiplexing by immobilizing full-length human HSP90α and HtpG of Helicobacter pylori on microarrays. Fluorescence-labeled ATP was competed by novel geldanamycin/reblastatin derivatives with IC50 values in the range of 0.5 nM to 4 μM and Z(*)-factors between 0.60 and 0.96. Our results demonstrate the potential of a target-oriented multiplexed protein microarray to identify novel inhibitors for different members of the HSP90 family. Copyright © 2014 Elsevier B.V. All rights reserved.
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Nobusawa, Takashi; Okushima, Yoko; Nagata, Noriko; Kojima, Mikiko; Sakakibara, Hitoshi; Umeda, Masaaki
2013-01-01
Plant organ growth is controlled by inter-cell-layer communication, which thus determines the overall size of the organism. The epidermal layer interfaces with the environment and participates in both driving and restricting growth via inter-cell-layer communication. However, it remains unknown whether the epidermis can send signals to internal tissue to limit cell proliferation in determinate growth. Very-long-chain fatty acids (VLCFAs) are synthesized in the epidermis and used in the formation of cuticular wax. Here we found that VLCFA synthesis in the epidermis is essential for proper development of Arabidopsis thaliana. Wild-type plants treated with a VLCFA synthesis inhibitor and pasticcino mutants with defects in VLCFA synthesis exhibited overproliferation of cells in the vasculature or in the rib zone of shoot apices. The decrease of VLCFA content increased the expression of IPT3, a key determinant of cytokinin biosynthesis in the vasculature, and, indeed, elevated cytokinin levels. These phenotypes were suppressed in ipt3;5;7 triple mutants, and also by vasculature-specific expression of cytokinin oxidase, which degrades active forms of cytokinin. Our results imply that VLCFA synthesis in the epidermis is required to suppress cytokinin biosynthesis in the vasculature, thus fine-tuning cell division activity in internal tissue, and therefore that shoot growth is controlled by the interaction between the surface (epidermis) and the axis (vasculature) of the plant body. PMID:23585732