Synthesis and Conformational Analysis of Locked Carbocyclic Analogues of 1,3-Diazepinone Riboside, a High-Affinity Cytidine Deaminase Inhibitor

Cytidine deaminase (CDA) catalyzes the deamination of cytidine via a hydrated transition-state intermediate that results from the nucleophilic attack of zinc-bound water at the active site. Nucleoside analogues where the leaving NH3 group is replaced by a proton and prevent conversion of the transition state to product are very potent inhibitors of the enzyme. However, stable carbocyclic versions of these analogues are less effective as the role of the ribose in facilitating formation of hydrated species is abolished. The discovery that a 1,3-diazepinone riboside (4) operated as a tight-binding inhibitor of CDA independent of hydration provided the opportunity to study novel inhibitors built as conformationally locked, carbocyclic 1,3-diazepinone nucleosides to determine the enzyme’s conformational preference for a specific form of sugar pucker. This work describes the synthesis of two target bicyclo[3.1.0]hexane nucleosides, locked as north (5) and south (6) conformers, as well as a flexible analogue (7) built with a cyclopentane ring. The seven-membered 1,3-diazepinone ring in all the three targets was built from the corresponding benzoyl-protected carbocyclic bis-allyl ureas by ring-closing metathesis. The results demonstrate CDA’s binding preference for a south sugar pucker in agreement with the high-resolution crystal structures of other CDA inhibitors bound at the active site

Synthesis and Conformational Analysis of Locked Carbocyclic Analogues of 1,3-Diazepinone Riboside, a High-Affinity Cytidine Deaminase Inhibitor

Cytidine deaminase (CDA) catalyzes the deamination of cytidine via a hydrated transition-state intermediate that results from the nucleophilic attack of zinc-bound water at the active site. Nucleoside analogues where the leaving NH3 group is replaced by a proton and prevent conversion of the transition state to product are very potent inhibitors of the enzyme. However, stable carbocyclic versions of these analogues are less effective as the role of the ribose in facilitating formation of hydrated species is abolished. The discovery that a 1,3-diazepinone riboside (4) operated as a tight-binding inhibitor of CDA independent of hydration provided the opportunity to study novel inhibitors built as conformationally locked, carbocyclic 1,3-diazepinone nucleosides to determine the enzyme’s conformational preference for a specific form of sugar pucker. This work describes the synthesis of two target bicyclo[3.1.0]hexane nucleosides, locked as north (5) and south (6) conformers, as well as a flexible analogue (7) built with a cyclopentane ring. The seven-membered 1,3-diazepinone ring in all the three targets was built from the corresponding benzoyl-protected carbocyclic bis-allyl ureas by ring-closing metathesis. The results demonstrate CDA’s binding preference for a south sugar pucker in agreement with the high-resolution crystal structures of other CDA inhibitors bound at the active site

Structural and functional analyses of minimal phosphopeptides targeting the polo-box domain of polo-like kinase 1

Polo-like kinase-1 (Plk1) has a pivotal role in cell proliferation and is considered a potential target for anticancer therapy. The noncatalytic polo-box domain (PBD) of Plk1 forms a phosphoepitope binding module for protein-protein interaction. Here, we report the identification of minimal phosphopeptides that specifically interact with the PBD of human PLK1, but not those of the closely related PLK2 and PLK3. Comparative binding studies and analyses of crystal structures of the PLK1 PBD in complex with the minimal phosphopeptides revealed that the C-terminal SpT dipeptide functions as a high-affinity anchor, whereas the N-terminal residues are crucial for providing specificity and affinity to the interaction. Inhibition of the PLK1 PBD by phosphothreonine mimetic peptides was sufficient to induce mitotic arrest and apoptotic cell death. The mode of interaction between the minimal peptide and PBD may provide a template for designing therapeutic agents that target PLK1.National Institutes of Health (U.S.) (Grant R01 GM60594)National Cancer Institute (U.S.)National Institutes of Health (U.S.) (Contract N01-CO-12400)National Institutes of Health (U.S.) (HHSN261200800001E

dockingstudyofhdacimplicationforbenzamideinhibitorsbindingmode

通过计算机模拟的对接过程研究，发现了MS-275——一种苯甲酰胺类的组蛋白去乙酰酶(HDAC)抑制剂与酶的可能的全新结合方式．这种结合方式与已经阐明的组蛋白去乙酰酶类似蛋白(HDLP)与曲古柳菌素A(trichostatin A，TSA)和suberoylanilide hydroxamic acid(SAHA)形成的复合物晶体结构中配体与酶的作用方式完全不同．从对接结果看，MS-275的作用靶点在酶活性口袋的最狭窄部位，而不是直接作用于锌离子．这似乎能够解释MS-275的低毒性特点，并且为设计和筛选全新的HDAC抑制剂提供了新思路

Glabridin Ameliorates Alcohol-Caused Liver Damage by Reducing Oxidative Stress and Inflammation via p38 MAPK/Nrf2/NF-κB Pathway

Licorice is a traditional and versatile herbal medicine and food. Glabridin (Gla) is a kind of isoflavone extracted from the licorice root, which has anti-obesity, anti-atherosclerotic, and antioxidative effects. Alcoholic liver disease (ALD) is a widespread liver disease induced by chronic alcohol consumption. However, studies demonstrating the effect of Gla on ALD are rare. The research explored the positive effect of Gla in C57BL/6J mice fed by the Lieber–DeCarli ethanol mice diet and HepG2 cells treated with ethanol. Gla alleviated ethanol-induced liver injury, including reducing liver vacuolation and lipid accumulation. The serum levels of inflammatory cytokines were decreased in the Gla-treated mice. The reactive oxygen species and apoptosis levels were attenuated and antioxidant enzyme activity levels were restored in ethanol-induced mice by Gla treatment. In vitro, Gla reduced ethanol-induced cytotoxicity, nuclear factor kappa B (NF-κB) nuclear translocation, and enhanced nuclear factor (erythroid-derived 2)-like 2 (Nrf2) nuclear translocation. Anisomycin (an agonist of p38 MAPK) eliminated the positive role of Gla on ethanol-caused oxidative stress and inflammation. On the whole, Gla can alleviate alcoholic liver damage via the p38 MAPK/Nrf2/NF-κB pathway and may be used as a novel health product or drug to potentially alleviate ALD

Lycopene inhibits carrageenan-induced thrombi by regulating AKT/FoxO3a and TLR4/NF-κB pathways

Lycopene (LYC) is a natural phytonutrient with various bioactivities, such as anti-oxidative stress and anti-inflammation. In this study, human endothelial cells (HUVECs), macrophages and human platelets, and carrageenan-induced thrombosis mouse model were used to evaluate the antithrombosis effects of LYC. In vitro, LYC reduced reactive oxygen species (ROS) production by activating antioxidant enzymes and inhibiting cellular inflammatory factors. LYC inhibited platelets activation by enhancing antioxidant enzymes expression through reducing AKT/FoxO3a signaling pathway. In vivo, LYC effectively improved carrageenan-induced thrombosis in mouse tail, liver and lung tissues. Additionally, in mouse liver and lung tissues, LYC reduced inflammation by inhibiting toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB) pathway, and inhibited oxidative stress by increasing antioxidant enzymes expression. In conclusion, LYC can inhibit thrombosis in mouse model, which suggesting that LYC could act as a potential functional food for prevention or treatment of thrombus

Discovery of Novel Class I Histone Deacetylase Inhibitors with Promising in Vitro and in Vivo Antitumor Activities

A successful structure-based design of novel cyclic depsipeptides that selectively target class I HDAC isoforms is described. Compound <b>11</b> has an IC₅₀ of 2.78 nM for binding to the HDAC1 protein, and the prodrugs <b>12</b> and <b>13</b> also exhibit promising antiproliferative activities in the nanomolar range against various cancer cell lines. Compounds <b>12</b> and <b>13</b> show more than 20-fold selectivity toward human cancer cells over human normal cells in comparison with romidepsin (FK228), demonstrating low probability of toxic side effects. In addition, compound <b>13</b> exhibits excellent in vivo anticancer activities in a human prostate carcinoma (Du145) xenograft model with no observed toxicity. Thus, prodrug <b>13</b> has therapeutic potential as a new class of anticancer agent for further clinical translation