Synthesis and identification of a novel skeleton of N-(pyridin-3-yl) proline as a selective CDK4/6 inhibitor with anti-breast cancer activities.

CDK4/6 were attractive chemotherapeutic targets for the treatment of malignant tumors, CDK4/6 selective inhibitors have made outstanding contributions in the treatment of breast cancer. However, these inhibitors share a single skeleton of N-(pyridin-2-yl) pyrimidin-2-amine which cannot overcome the side effects in clinical application. In our previous study, an N'- acetylpyrrolidine-1-carbohydrazide was hit as the initial fragment by analyzing the active site characteristics of CDK6. Two series of N-(pyridin-3-yl) proline were obtained by fragment growth method. The QSAR study was carried out according to the in vitro activities data against CDK4/6, and two compounds 7c and 7p with potent inhibitory activities were found to interact with CDK4 in different binding conformation. They showed potential inhibition of cell proliferation against the breast cancer cell, and 7c exhibited promised anti-breast cancer effect in vivo.

Synthesis and biological evaluation of novel (E)-N'-benzylidene hydrazides as novel c-Met inhibitors through fragment based virtual screening.

C-Met plays a crucial role in the development and progression of neoplastic disease. Type II c-Met inhibitors recognise the inactive DFG-out conformation of the kinase, result in better anti-tumour effects due to synergistic effect against the other kinases. According to our previous works, an (E)-N'-benzylidene group was selected as the initial fragment. Two series of (E)-N'-benzylidene hydrazides were designed by fragment growth method. The inhibitory activities were in vitro investigated against c-Met and VEGFR-2. Compound 10b exhibited the most potent inhibitory activity against the c-Met inhibitor (IC50 = 0.37 nM). Compound 11b exhibited multi-target c-Met kinase inhibitory activity as a potential type II c-Met inhibitor (IC50 = 3.41 nM against c-Met; 25.34 nM against VEGFR-2). The two compounds also demonstrate the feasibility of fragment-based virtual screening method for drug discovery.

Identification of novel CDK2 inhibitors by a multistage virtual screening method based on SVM, pharmacophore and docking model.

Cyclin-dependent kinase 2 (CDK2) is the family of Ser/Thr protein kinases that has emerged as a highly selective with low toxic cancer therapy target. A multistage virtual screening method combined by SVM, protein-ligand interaction fingerprints (PLIF) pharmacophore and docking was utilised for screening the CDK2 inhibitors. The evaluation of the validation set indicated that this method can be used to screen large chemical databases because it has a high hit-rate and enrichment factor (80.1% and 332.83 respectively). Six compounds were screened out from NCI, Enamine and Pubchem database. After molecular dynamics and binding free energy calculation, two compounds had great potential as novel CDK2 inhibitors and they also showed selective inhibition against CDK2 in the kinase activity assay.

Identification of Novel PI3Kδ Selective Inhibitors by SVM-Based Multistage Virtual Screening and Molecular Dynamics Simulations.

Phosphoinositide 3 kinase delta (PI3Kδ) is a lipid kinase that has been implicated in a variety of immune mediated disorders. The research on isoform selectivity was crucial for reducing side effects. In the current study, an optimized hierarchical multistage virtual screening method was utilized for screening the PI3Kδ selective inhibitors. The method sequentially applied a support vector machine (SVM), a protein ligand interaction fingerprint (PLIF) pharmacophore, and a molecular docking approach. The evaluation of the validation set showed a high hit rate and a high enrichment factor of 75.1% and 301.66, respectively. This multistage virtual screening method was then utilized to screen the NCI database. From the final hit list, Compound 10 has great potential as the PI3Kδ inhibitor with micromolar inhibition in the PI3Kδ kinase activity assay. This compound also shows selectivity against PI3Kδ kinase. The method combining SVM, pharmacophore, and docking was capable of screening out the compounds with potential PI3Kδ selective inhibitors. Moreover, structural modification of Compound 10 will contribute to investigating the novel scaffold and designing novel PI3Kδ inhibitors.

[Resveratrol reduces inflammatory cytokines via inhibiting nuclear factor-κB and mitogen-activated protein kinase signal pathway in a rabbit atherosclerosis model].

OBJECTIVE: Inflammation serves as the initial pathologic step of cardiovascular diseases including atherosclerosis. Resveratrol possesses many pharmacological properties including antioxidant, cardioprotective and anti-cancer effects. In this study, we investigate the anti-inflammatory effect and mechanisms of resveratrol in an atherosclerotic rabbit model. METHODS: Rabbit were assigned to six groups (n = 10 each): control, high fat diet group, resveratrol low, medium and high dose groups, resveratrol pretreatment group. The serum tumor necrosis factor-α (TNF- α), interleukin-6 (IL-6) and interleukin-1ß (IL-1ß) were analyzed by Enzyme-linked immuno sorbent assay(ELISA). Phosphorylation levels of mitogen-activated protein kinases (MAPKs) cascades and NF-κB were determined by Western blot. RESULTS: Compared with the control group, the expression of serum inflammatory factors IL-1ß, IL-6, TNF-α were increased in high-fat group (all P < 0.05). Compared with high-fat group, the expressions of IL-6, IL-1ß, TNF-α were significantly reduced in resveratrol low, medium, high dose groups and resveratrol pretreatment group (all P < 0.01), and this effect is dose-dependent. In addition, the NF-κB, p38MAPK, JNK, ERK1/2 protein phosphorylation in high-fat group were significantly upregulated compared with control group (P < 0.05), which (except ERK1/2 phosphorylation level) were significantly downregulated in resveratrol treatment group and resveratrol pretreatment group. CONCLUSION: This study indicates that resveratrol reduces serum inflammatory cytokines in this atherosclerotic rabbit model via down-regulation phosphorylation of NF-κB, and MAPKs signaling, which might serve as the anti-inflammatory molecular basis of resveratrol.

[VEGF165-induced angiogenesis by regulating intracellular free Mg2+ in HUVECs].

AIM: The mechanism of vascular endothelial growth factor165 (VEGF165) on intracellular free magnesium ([Mg2+]i) in human umbilical vein endothelial cells (HUVECs) was investigated. METHODS: [Mg2+]i in HUVECs loaded with fluorescent magnesium indicator mag-fura-2 were quantitatively detected the use of intracellular cation measurement system. RESULTS: VEGF165 significantly increased [Mg2+]i in the extracellular Mg2+ and this effect could be blocked by pretreatment with tyrosine kinase inhibitors (tyrphostin A23 and genistein), phosphatidylinositol 3-kinase (PI3K) inhibitors (wortmannin and LY294002) and phospholipase Cgamma (PLCgamma) inhibitor (U73122). In contrast, phospholipase Cgamma (PLCgamma) inhibitor analog (U73343), mitogen-activated protein kinase inhibitors (SB202190 and PD98059) had no effect on the VEGF165-induced [Mg2+]i increase. CONCLUSION: The increase of [Mg2+]i by VEGF165 originates from intracellular Mg2+ pool through tyrosine kinase/ PI3K/PLCgamma-dependent signaling pathways.