分类: 生物学 >> 生态学 提交时间: 2017-11-17
摘要: The marketed DPP-IV inhibitors represented by Vildagliptin, Saxagliptin, and Alogliptin trigged the discovery of tens thousands of novel DPP-IV inhibitors. Inspired by the good potency and easily structural modification, we initiated a series of modification of Aloglitpin with classic medicinal chemistry strategies. Herein, we reviewed how we generated diverse and highly potent inhibitors X (IC50= 0.3 nM), Y (IC50= 3.6 nM), Z (IC50= nM), and E (IC50= 1.4 nM) through scaffold hopping triggered optimization, B (IC50= 0.7 nM), C (IC50= 0.4 nM), A (IC50= nM) through pharmacophorehybridization based lead generation, F (IC50= nM) via the extendedcombination of these strategies.In this way, the development of DPP-IV inhibitors will eventually become the classic case in themedicinal chemistry history like COX-2 inhibitors and sulfonamides.
分类: 生物学 >> 生态学 提交时间: 2020-11-24
摘要: A series of 2-aminopyrimidine derivatives were designed and synthesized as highly selective FGFR4 inhibi-tors. One of the most promising compounds 2n tightly bound FGFR4 with a Kd value of 3.3 nM and potently inhibited its enzymatic activity with an IC50 value of 2.6 nM, but completely spared FGFR1/2/3. The compound selectively suppressed proliferation of breast cancer cells harboring dysregulated FGFR4 signaling with an IC50 value of 0.38 μM. Furthermore, 2n exhibited extraordinary target specificity in a Kinome-wide screen against 468 kinases, with S(35) and S(10) selectivity scores of 0.01 and 0.007 at 1.0 μM, respectively.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-11-17
摘要: The structural superposition of DPP-IV complex with Alogliptin and Linagliptin displayed a similar binding mode. The butynyl of Linagliptin and cyanobenzyl of Alogliptin occupy the S1 pocket which therefore could be mutually switched. Thus a pharmacophore hybridization of Alogliptin was initiated and led to a novel DPP-IV inhibitor 61. Though it did not exhibit desired activity (IC50= 0.2 礛), the butynyl compound acts as a lead compound triggered a following structural optimization. A novel series of potent DPP-IV inhibitors represented by compound 77 (IC50= 0.36 nM) were obtained with a robust pharmacokinetic profile and better in vitro and in vivo efficacy than Alogliptin.
分类: 物理学 >> 核物理学 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: The N-terminal domain of heat shock protein 90 (Hsp90N) is responsible for the catalytic activity of Hsp90. The reported inhibitors of Hsp90 bind to this domain and would inhibit tumor growth and progression. Here, we synthesized FS23, a small molecule inhibitor of hsp90 and collected X-ray diffraction data of the complex crystal of Hsp90-FS23. High resolution X-ray crystallography shows that FS23 interacted with Hsp90N at the nucleotide binding cleft, and this suggests that FS23 may complete with nucleotides to bind to Hsp90N. The crystal structure and the interaction between Hsp90N and FS23 suggest a rational basis for the design of novel antitumor drugs.
分类: 生物学 >> 生态学 提交时间: 2017-11-17
摘要: Drug compliance is critical for the patients with chronic diseases like diabetes. In our continuous effort to find better glucose lowering agents, an exploration for long-acting DPP-4 inhibitor had been launched. Based on our previous reported compound 111 bearing a pyrrolopyrimidine scaffold, lead compound 114 (IC50 = 2.3 nM, t1/2(rat) = 5.46 h) was rapidly determined with the pharmacokinetic superiority. Further SAR study indicated that the pyrrole ring was generally tolerable for variation, in which the β-substitution gave a better DPP-4 affinity. In depth evaluation on β position of pyrrole ring brought up with highly potent compound 124 (IC50 = 0.76 nM, t1/2(rat) = 7.89 h). In vivo pharmacodynamics tests demonstrated a similar or even slightly better sustained DPP-4 inhibition of compound 114 and 124 compared with the first marketed once-weekly drug Trelagliptin in this category, indicating that improvement of DPP-4 inhibitory activity or pharmacokinetic profile might be both feasible ways to rapid generation of long-acting DPP-4 inhibitors.
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-11-17
摘要: A new chemical class of potent DPP-IV inhibitors has been structurally derived from our recently disclosed pyrrolopyrimidine scaffold by replacing cyanobenzyl with butynyl group. Systematic variations and structure-activity relationship studies have been conducted on the starting hit 51 (IC50= 0.46 μM). Consequently, compound 78 (IC50= 1.55 nM) was identified to be a potent, selective, and orally available lead, worth further evaluations and optimizations.
分类: 生物学 >> 生态学 提交时间: 2017-11-17
摘要: A novel dipeptidyl peptidase IV inhibitor hit (5, IC50 = 0.86 mu M) was structurally derived from our recently disclosed preclinical candidate 4 by replacing the cyanobenzyl with a butynyl based on pharmacophore hybridization. A hit-to-lead optimization effort was then initiated to improve its potency. Most N-substituted analogs exhibited good in vitro activity, and compound 180 (IC50 = 1.55 nM) was identified to be a potent dipeptidyl peptidase IV inhibitor with a significantly improved pharmacokinetic properties (bioavailablity: 41% vs 82.9%; T-1/2: 2 h vs 4.9 h). (C) 2013 Elsevier Ltd. All rights reserved.
分类: 生物学 >> 生态学 提交时间: 2017-11-17
摘要: We previously reported a highly potent DPP-IV inhibitor 6 with low in vivo efficacy. While trying to maintain consistent in vitro and in vivo biological activity, we initiated a pharmacokinetic property-driven optimization to improve the metabolic stability and permeability of inhibitor 6. A simple scaffold replacement of thienopyrimidine with pyrrolopyrimidine (21a) led to significantly improved metabolic stability (4% vs. 65% remaining). Further modification of the pyrrolopyrimidine scaffold to produce compound 21j resulted in much better oral bioavailability than 6. Importantly, compound 21j exhibits greater in vivo efficacy than does 6 and Alogliptin and is worthy of further development. (C) 2012 Elsevier Masson SAS. All rights reserved.
分类: 生物学 >> 生物物理学 >> 神经科学 提交时间: 2016-05-11
摘要: All neurodegenerative diseases are associated with oxidative stress-induced neuronal death. Forkhead box O3a (FOXO3a) is a key transcription factor involved in neuronal apoptosis. However, how FOXO3a forms complexes and functions in oxidative stress processing remains largely unknown. In the present study, we show that histone deacetylase 2 (HDAC2) forms a physical complex with FOXO3a, which plays an important role in FOXO3a-dependent gene transcription and oxidative stress-induced mouse cerebellar granule neuron (CGN) apoptosis. Interestingly, we also found that HDAC2 became selectively enriched in the promoter region of the p21 gene, but not those of other target genes, and inhibited FOXO3a-mediated p21 transcription. Furthermore, we found that oxidative stress reduced the interaction between FOXO3a and HDAC2, leading to an increased histone H4K16 acetylation level in the p21 promoter region and upregulated p21 expression in a manner independent of p53 or E2F1. Phosphorylation of HDAC2 at Ser 394 is important for the HDAC2-FOXO3a interaction, and we found that cerebral ischemia/reperfusion reduced phosphorylation of HDAC2 at Ser 394 and mitigated the HDAC2-FOXO3a interaction in mouse brain tissue. Our study reveals the novel regulation of FOXO3a-mediated selective gene transcription via epigenetic modification in the process of oxidative stress-induced cell death, which could be exploited therapeutically.
分类: 生物学 >> 生物物理学 >> 肿瘤学 提交时间: 2016-05-11
摘要: Dasatinib-based therapy is often used as a second-line therapeutic strategy for imatinib-resistance gastrointestinal stromal tumors (GISTs); however, acquired aberrant activation of dasatinib target proteins, such as c-KIT and PDGFR13, attenuates the therapeutic efficiency of dasatinib. Combination therapy which inhibits the activation of dasatinib target proteins may enhance the cytotoxicity of dasatinib in GISTs. Bortezomib, a proteasome inhibitor, significantly inhibited cell viability and promoted apoptosis of dasatinib-treated GIST-TI cells, whereas GIST-TI cells showed little dasatinib cytotoxicity when treated with dasatinib alone, as the upregulation of c-KIT caused by dasatinib itself interfered with the inhibition of c-KIT and PDGFRI3 phosphorylation by dasatinib. Bortezomib induced internalization and degradation of c-KIT by binding c-KIT to Cbl, an E3 ubiquitin-protein ligase, and the subsequent release of Apaf-1, which was originally bound to the c-KIT-Hsp903-Apaf-1 complex, induced primary apoptosis in GISTTI cells. Combined treatment with bortezomib plus dasatinib caused cell cycle arrest in the G1 phase through inactivation of PDGFRP and promoted bortezomib-induced apoptosis in GIST-TI cells. Our data suggest that combination therapy exerts better efficiency for eradicating GIST cells and may be a promising strategy for the future treatment of GISTs. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
分类: 生物学 >> 生物医药 提交时间: 2017-05-10
摘要: We recently described the discovery, genome, clinical features, genotypes and evolution of a novel and global human respiratory virus named human coronavirus HKU1 (HCoV-HKU1) which is not yet culturable. We expressed a C-terminal FLAG-tagged CoV-HKU1 spike (S) protein by the Semliki Forest Virus (SFV) system and investigated its maturation profile. Pulse chase labeling revealed that S-FLAG was expressed as high-mannose N-glycans of monomers and trimers. It was predominantly cleaved into subdomains S1 and S2 during maturation. S1 was secreted into the medium. Immunofluorescence analysis visualized S along the secretory pathway from endoplasmic reticulum to plasma membrane. Cleavage of S and release of HCoV-HKU1 S pseudotyped virus were inhibited by furin or furin-like enzyme inhibitors. The cell-based expressed full-length S-FLAG could be recognized by the convalescent serum obtained from a patient with HCoV-HKU1 pneumonia. The data suggest that the native form of HCoV-HKU1 spike expressed in our system can be used in developing serological diagnostic assay and in understanding the role of S in the viral life cycle. Exp Biol Med 233:1527-1536, 2008
分类: 材料科学 >> 材料科学(综合) 提交时间: 2017-05-09
摘要: In order to improve the mechanical durability, polyurethane (PU) needs to be modified to enhance the tribological and anti-corrosion properties. In this work, we fabricated a series of PU composite coatings reinforced with functionalized graphene (FG) and functionalized graphene oxide (FGO). The structural and morphological features of the composite coatings were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The results showed that the dispersion and compatibility of graphene and graphene oxide were improved via chemical modification. Moreover, they effectively enhanced the tribological and anti-corrosion properties of PU composite coatings, whose optimized additive range was between 0.25 wt% and 0.5 wt%. The effect depends on the balance of lubrication and barrier of fillers and cracks generated by them. Finally, in comparison with FG/PU coatings, the FGO/PU coatings exhibited a better tribological property but worse anti-corrosion property owing to the abundant oxygenated groups of GO. They led to stronger interfacial interactions between FGO and the PU matrix, but destroyed the graphene lattice structure to some extent.
分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-12
摘要: Papain-like protease (PLpro) of coronaviruses (CoVs) carries out proteolytic maturation of non-structural proteins that play a role in replication of the virus and performs deubiquitination of host cell factors to scuttle antiviral responses. Avian infectious bronchitis virus (IBV), the causative agent of bronchitis in chicken that results in huge economic losses every year in the poultry industry globally, encodes a PLpro. The substrate specificities of this PLpro are not clearly understood. Here, we show that IBV PLpro can degrade Lys(48)- and Lys(63)-linked polyubiquitin chains to monoubiquitin but not linear polyubiquitin. To explain the substrate specificities, we have solved the crystal structure of PLpro from IBV at 2.15-angstrom resolution. The overall structure is reminiscent of the structure of severe acute respiratory syndrome CoV PLpro. However, unlike the severe acute respiratory syndrome CoV PLpro that lacks blocking loop (BL) 1 of deubiquitinating enzymes, the IBV PLpro has a short BL1-like loop. Access to a conserved catalytic triad consisting of Cys(101), His(264), and Asp(275) is regulated by the flexible BL2. A model of ubiquitin-bound IBV CoV PLpro brings out key differences in substrate binding sites of PLpros. In particular, P3 and P4 subsites as well as residues interacting with the beta-barrel of ubiquitin are different, suggesting different catalytic efficiencies and substrate specificities. We show that IBV PLpro cleaves peptide substrates KKAG-7-amino-4-methylcoumarin and LRGG-7-amino-4-methylcoumarin with different catalytic efficiencies. These results demonstrate that substrate specificities of IBV PLpro are different from other PLpros and that IBV PLpro might target different ubiquitinated host factors to aid the propagation of the virus.
分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-11
摘要: Growing evidence suggests a strong association between cardiovascular risk factors and incidence of Alzheimer disease (AD). Asymmetric dimethylarginine (ADMA), the endogenous nitric oxide synthase inhibitor, has been identified as an independent cardiovascular risk factor and is also increased in plasma of patients with AD. However, whether ADMA is involved in the pathogenesis of AD is unknown. In this study, we found that ADMA content was increased in a transgenic Caenorhabditis elegans beta-amyloid (A beta) overexpression model, strain CL2006, and in human SH-SY5Y cells overexpressing the Swedish mutant form of human A beta precursor protein (APPsw). Moreover, ADMA treatment exacerbated A beta-induced paralysis and oxidative stress in CL2006 worms and further elevated oxidative stress and A beta secretion in APPsw cells. Knockdown of type 1 protein arginine N-methyltransferase to reduce ADMA production failed to show a protective effect against A beta toxicity, but resulted in more paralysis in CL2006 worms as well as increased oxidative stress and A beta secretion in APPsw cells. However, overexpression of dimethylarginine dimethylaminohydrolase 1 (DDAH1) to promote ADMA degradation significantly attenuated oxidative stress and A beta secretion in APPsw cells. Collectively, our data support the hypothesis that elevated ADMA contributes to the pathogenesis of AD. Our findings suggest that strategies to increase DDAH1 activity in neuronal cells may be a novel approach to attenuating AD development. (C) 2014 Elsevier Inc. All rights reserved.
分类: 生物学 >> 生物医药 提交时间: 2017-05-10
摘要: Chronic myeloid leukemia (CML) represents the first human malignancy successfully treated with a tyrosine kinase inhibitor (TKI; imatinib). However, early relapses and the emergence of imatinib-resistant disease are problematic. Evidence suggests that imatinib and other inhibitors may not effectively eradicate leukemic stem/progenitor cells, and that combination therapy directed to complimentary targets may improve treatment. Abelson helper integration site 1 (Ahi-1)/AHI-1 is a novel oncogene that is highly de-regulated in CML stem/progenitor cells where levels of BCR-ABL transcripts are also elevated. Here, we demonstrate that overexpression of Ahi-1/AHI-1 in murine and human hematopoietic cells confer growth advantages in vitro and induce leukemia in vivo, enhancing effects of BCR-ABL. Conversely, RNAi-mediated suppression of AHI-1 in BCR-ABL-transduced lin(-)CD34(+) human cord blood cells and primary CML stem/progenitor cells reduces their growth autonomy in vitro. Interestingly, coexpression of Ahi-1 in BCR-ABL-inducible cells reverses growth deficiencies exhibited by BCR-ABL down-regulation and is associated with sustained phosphorylation of BCR-ABL and enhanced activation of JAK2-STAT5. Moreover, we identified an AHI-1-BCR-ABL-JAK2 interaction complex and found that modulation of AHI-1 expression regulates phosphorylation of BCR-ABL and JAK2-STAT5 in CML cells. Importantly, this complex mediates TKI response/resistance of CML stem/progenitor cells. These studies implicate AHI-1 as a potential therapeutic target downstream of BCR-ABL in CML.
分类: 生物学 >> 生态学 提交时间: 2017-11-17
摘要: 截至目前,已有7个二肽基肽酶IV(DPP-IV)抑制剂成为抗糖尿病新药,它们的结构差异和内在关联性为进一步的结构修饰提供了新的思路。本研究针对阿格列汀和利那列汀的结构特征,采用骨架跃迁及药物拼接的原理,快速得到了新型的DPP-IV抑制剂8g (IC50= 4.9 nM),其活性和选择性均接近于上市新药。因此,运用经典的药物化学策略,对基于同一靶标的上市药物实施分子操作,可以有效地产生新型的活性分子。