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Herein we report the discovery of a series of new small molecule inhibitors of histone lysine demethylase 4D (KDM4D). Molecular docking was first performed to screen for new KDM4D inhibitors from various chemical databases. Two hit compounds were retrieved. Further structural optimization and structure-activity relationship (SAR) analysis were carried out to the more selective one, compound 2 , which led to the discovery of several new KDM4D inhibitors. Among them, compound 10r is the most potent one with an IC 50 value of 0.41 ± 0.03 μM against KDM4D. Overall, compound 10r could be taken as a good lead compound for further studies. [ABSTRACT FROM AUTHOR]

Lysine specific demethylase 1 (LSD1) plays an important role in regulating histone lysine methylation at residues K4 and K9 on histone H3 and is recognized as an attractive therapeutic target in multiple malignancies. In this study, a series of novel ( E )- N ′-(2,3-dihydro-1 H -inden-1-ylidene) benzohydrazides were synthesized and biologically evaluated for their potential LSD1 inhibitory effect. Among them, compounds 5a and 5n showed the most potent LSD1 inhibitory activity with IC 50 values of 1.4 and 1.7 nM, respectively, which were about 10 times more potent compared with ( E )- N -(1-(5-chloro-2-hydroxyphenyl) ethylidene)-3-(morpholinosulf-only) benzohydrazide ( J. Med. Chem. 2013 , 56, 9496–9508; as reference compound). Compounds 5a and 5n also exhibited marked anti-proliferation activities against cancer cell lines that highly expressed LSD1. These results suggest that these optimized compounds might be served as promising LSD1 inhibitors against cancer, which merit further study. [ABSTRACT FROM AUTHOR]

Herein we report the discovery of a series of new KDM5A inhibitors. A three-dimensional (3D) structure model of KDM5A jumonji domain was firstly established based on homology modeling. Molecular docking-based virtual screening was then performed against commercial chemical databases. A number of hit compounds were retrieved. Further structural optimization and structure–activity relationship (SAR) analysis were carried out to the most active hit compound, 9 (IC 50 : 2.3 μM), which led to the discovery of several new KDM5A inhibitors. Among them, compound 15e is the most potent one with an IC 50 value of 0.22 μM against KDM5A. This compound showed good selectivity for KDM5A and considerable ability to suppress the demethylation of H3K4me3 in intact cells. Compound 15e could be taken as a good lead compound for further studies. [ABSTRACT FROM AUTHOR]

Despite a potential application of PRMT1 inhibitors in cancer treatment, very few of PRMT1 inhibitors have been reported. To obtain novel potent PRMT1 inhibitors, structure optimizations towards a hit compound, 4-((6-chloro-5-nitropyrimidin-4-yl)amino)benzimidamide, were carried out. A series of 4-((5-nitropyrimidin-4-yl)amino)benzimidamide derivatives were synthesized. Structure–activity relationship analysis led to the discovery of a number of PRMT1 inhibitors. The most potent compound corresponds to compound 6d , which showed an IC 50 value of 2.0 μM against PRMT1. This compound also displayed a considerable anti-proliferative activity against three tumor cell lines, DLD-1, T24 and SH-SY-5Y, with IC 50 values of 4.4 μM, 13.1 μM and 11.4 μM, respectively. [ABSTRACT FROM AUTHOR]

A potential fluorescence probe for in vivo detection of cerebral β-amyloid fibrils, ( E )-2-(2-(2-(5-(dimethylamino)thiophen-2-yl)vinyl)-6-methyl-4 H -pyran-4-ylidene)malononitrile (PT-1), was synthesized and evaluated. In experiments in vitro, PT-1 exhibited clear labeling of β-amyloid fibrils and significant fluorescence changes upon binding to aggregated β-amyloid fibrils. It also showed favorite kinetics in the brain, which is critical for cerebral imaging. In vivo fluorescence imaging with PT-1 and semi-quantitative analysis of the images further confirmed noninvasive visualization of cerebral β-amyloid fibrils in vivo and obvious distinction between APP/PS1 transgenic mice and wild-type controls. The results demonstrate the potential of PT-1 as a novel fluorescence probe for noninvasive prediction of cerebral β-amyloid fibrils. [ABSTRACT FROM AUTHOR]

In this investigation, a series of 6-phenylimidazo[2,1- b ]thiazole derivatives were synthesized. Structure–activity relationship (SAR) analysis of these compounds based on cellular assays led to the discovery of a number of compounds that showed potent activity against FLT3-dependent human acute myeloid leukemia (AML) cell line MV4-11, but very weak or no activity against FLT3-independent human cervical cancer cell line Hela. FLT3 kinase inhibition assays were then performed on the three most active compounds. Among these compounds, 6-(4-(3-(5-( tert -butyl)isoxazol- 3-yl)ureido)phenyl)- N -(3-(dimethylamino)propyl)imidazo[2,1- b ]thiazole-3-carboxamide ( 19 ) exhibited the highest potency in both cellular (MV4-11, IC 50 : 0.002 μM) and enzymatic (FLT3, IC 50 : 0.022 μM) assays. Further in-depth in vitro anti-AML activity and mechanism of action studies were carried out on compound 19 . [ABSTRACT FROM AUTHOR]

Abstract: Current treatment for hepatitis C is barely satisfactory, there is an urgent need to develop novel agents for combating hepatitis C virus infection. This study discovered a new class of thieno[2,3-b]pyridine derivatives as HCV inhibitors. First, a hit compound characterized by a thienopyridine core was identified in a cell-based screening of our privileged small molecule library. And then, structure activity relationship study of the hit compound led to the discovery of several potent compounds without obvious cytotoxicity in vitro (12c, EC50 =3.3μM, SI >30.3, 12b, EC50 =3.5μM, SI >28.6, 10l, EC50 =3.9μM, SI >25.6, 12o, EC50 =4.5μM, SI >22.2, respectively). Although the mechanism of them had not been clearly elucidated, our preliminary optimization of this class of compounds had provided us a start point to develop new anti-HCV agents. [Copyright &y& Elsevier]

Abstract: Development of glutamate non-competitive antagonists of mGluR1 (Metabotropic glutamate receptor subtype 1) has increasingly attracted much attention in recent years due to their potential therapeutic application for various nervous disorders. Since there is no crystal structure reported for mGluR1, ligand-based virtual screening (VS) methods, typically pharmacophore-based VS (PB-VS), are often used for the discovery of mGluR1 antagonists. Nevertheless, PB-VS usually suffers a lower hit rate and enrichment factor. In this investigation, we established a multistep ligand-based VS approach that is based on a support vector machine (SVM) classification model and a pharmacophore model. Performance evaluation of these methods in virtual screening against a large independent test set, M-MDDR, show that the multistep VS approach significantly increases the hit rate and enrichment factor compared with the individual SB-VS and PB-VS methods. The multistep VS approach was then used to screen several large chemical libraries including PubChem, Specs, and Enamine. Finally a total of 20 compounds were selected from the top ranking compounds, and shifted to the subsequent in vitro and in vivo studies, which results will be reported in the near future. [Copyright &y& Elsevier]

Abstract: A series of novel benzothiazole-2-thiol derivatives were synthesized, and their anti-proliferative activities on HepG2 and MCF-7 cells were investigated. Most compounds had inhibitory effects on cell growth, and some of them were more effective than cisplatin. Compounds 6m and 6t displayed good inhibitory activities against a panel of different types of human cancer cell lines, with IC50 values in the low micromolar range. Further biological evaluation indicated that 6m induced apoptosis in HepG2 cancer cells. Structure–activity relationships were also proposed. [Copyright &y& Elsevier]

Abstract: Novel thienopyridine derivatives 1b–1r were synthesized, based on a hit compound 1a that was found in a previous cell-based screening of anticancer drugs. Compounds 1a–1r have the following features: (1) their anticancer activity in vitro was first reported by our group. (2) The most potent analog 1g possesses hepatocellular carcinoma (HCC)-specific anticancer activity. It can specifically inhibit the proliferation of the human hepatoma HepG2 cells with an IC50 value of 0.016μM (compared with doxorubicin as a positive control, whose IC50 was 0.37μM). It is inactive toward a panel of five different types of human cancer cell lines. (3) Compound 1g remarkably induces G0/G1 arrest and apoptosis in HepG2 cells in vitro at low micromolar concentrations. These results, especially the HCC-specific anticancer activity of 1g, suggest their potential in targeted chemotherapy for HCC. [ABSTRACT FROM AUTHOR]

Abstract: In this investigation, chemical features based 3D pharmacophore models were developed based on the known inhibitors of Spleen tyrosine kinase (Syk) with the aid of hiphop and hyporefine modules within catalyst. The best quantitative pharmacophore model, Hypo1, was used as a 3D structural query for retrieving potential inhibitors from chemical databases including Specs, NCI, MayBridge, and Chinese Nature Product Database (CNPD). The hit compounds were subsequently subjected to filtering by Lipinski’s rule of five and docking studies to refine the retrieved hits. Finally 30 compounds were selected from the top ranked hit compounds and conducted an in vitro kinase inhibitory assay. Six compounds showed a good inhibitory potency against Syk, which have been selected for further investigation. [Copyright &y& Elsevier]

Abstract: Pharmacophore models of Polo-like kinase-1 (PLK1) inhibitors have been established by using the HipHop and HypoGen algorithms implemented in the Catalyst software package. The best quantitative pharmacophore model, Hypo1, which has the highest correlation coefficient (0.9895), consists of one hydrogen bond acceptor, one hydrogen bond donor, one hydrophobic feature, and one hydrophobic aliphatic feature. Hypo1 was further validated by test set and cross validation method. Then Hypo1 was used as a 3D query to screen several databases including Specs, NCI, Maybridge, and Chinese Nature Product Database (CNPD). The hit compounds were subsequently subjected to filtering by Lipinski’s rule of five and docking study to refine the retrieved hits and as a result to reduce the rate of false positive. Finally, a total of 20 compounds were selected and have been shifted to in vitro and in vivo studies. As far as we know, this is the first report on the pharmacophore modeling even the first publicly reported virtual screening study of PLK1 inhibitors. [Copyright &y& Elsevier]

Abstract: Development of fatty acid synthase (FAS) inhibitors has increasingly attracted much attention in recent years due to their potential therapeutic use in obesity and cancers. In this investigation, pharmacophore modeling based on the first crystal structure of human KS domain of FAS was carried out. The established pharmacophore model was taken as a 3D query for retrieving potent FAS inhibitors from the chemical database Specs. Docking study was further carried out to refine the obtained hit compounds. Finally, a total of 28 compounds were selected based on the ranking order and visual examination, which were first evaluated by a cell line-based assay. Seven compounds that have good inhibition activity against two FAS overexpressing cancer cell lines were further evaluated by an enzyme-based assay. One compound with a new chemical scaffold was found to have low micromolar inhibition potency against FAS, which has been subjected to further chemical structural modification. [Copyright &y& Elsevier]

Herein, we report the discovery of a series of thieno[2,3- d ]pyrimidin-4(3 H)-one derivatives as a new class of ROCK inhibitors. Structure-activity relationship studies of these compounds led to the identification of the most potent compound, 3-(3-methoxybenzyl)-6-(1 H -pyrrolo[2,3- b ]pyridin-4-yl)thieno[2,3- d ]pyrimidin-4(3 H)-one (8k), which showed IC 50 values of 0.004 μM and 0.001 μM against ROCK Ⅰ and ROCK Ⅱ, respectively. In vitro , 8k significantly reduced the phosphorylation level of ROCK downstream signaling protein and induce changes in cell morphology and migration. Overall, this study provides a promising lead compound for drug discovery targeting ROCKs. [ABSTRACT FROM AUTHOR]