Xin Zhai

Discovery and optimization of novel 4-phenoxy-6,7-disubstituted quinolines possessing semicarbazones as c-Met kinase inhibitors.

A novel series of N(1)-(3-fluoro-4-(6,7-disubstituted-quinolin-4-yloxy)phenyl)-N(4)-arylidenesemicarbazide derivatives were synthesized and evaluated for their c-Met kinase inhibition and cytotoxicity against A549, HT-29, MKN-45 and MDA-MB-231 cancer cell lines in vitro. Several potent compounds were further evaluated against three other cancer cell lines (U87MG, NCI-H460 and SMMC7721). Most of compounds tested exhibited moderate to excellent activity. The studies of SARs identified the most promising compound 28 (c-Met IC50=1.4nM) as a c-Met kinase inhibitor. In this study, a promising compound 28 was identified, which displayed 2.1-, 3.3-, 48.4- and 3.6-fold increase against A549, HT-29, U87MG and NCI-H460 cell lines, respectively, compared with that of Foretinib.

Exploration of (S)-3-aminopyrrolidine as a potentially interesting scaffold for discovery of novel Abl and PI3K dual inhibitors

Based on the literature-reported compensatory effect of PI3K on Abl inhibition and the improved preclinical effect of drug combination of Abl and PI3K inhibitors, a series of compounds bearing novel scaffold of (S)-3-aminopyrrolidine was identified as Abl and PI3K dual inhibitors through support vector machine screening tool, which were subsequently synthesized and tested. Most compounds demonstrated promising cytoxicity against a CML leukemia cell-line K562 and moderate inhibition against Abl and PI3K kinases. These compounds induced no apoptosis in K562 cell-line, suggesting that their cytotoxic activities are unlikely duo to other known anti-CML mechanisms. Molecular docking study further showed that the compound 5k could bind with both Abl and PI3K, but the weaker binding with Abl compared to Imatinib is consistent with its low kinase inhibitory rates. These plus literature-reported evidences suggest that the promising cytotoxic effect of our novel compounds might be due to the collective effect of Abl and PI3K inhibition.

Synthesis and anti-hepatitis B virus evaluation of novel ethyl 6-hydroxyquinoline-3-carboxylates in vitro

A series of non-nucleoside ethyl 6-hydroxyquinoline-3-carboxylate derivatives were prepared and evaluated in HepG2.2.15 cells. Most compounds inhibited the expression of viral antigens HBsAg or HBeAg at low concentration. Six compounds, 9f(3), 12b(6), 12f(6), 13b(2), 13b(6), and 13f(6), displayed excellent intracellular inhibitory activity and selectivity towards the replication of HBV DNA. Of these six initial hits, compound 13b(6) was the most active.

Design, synthesis, biological evaluation and preliminary mechanism study of novel benzothiazole derivatives bearing indole-based moiety as potent antitumor agents.

Through a structure-based molecular hybridization approach, a series of novel benzothiazole derivatives bearing indole-based moiety were designed, synthesized and screened for in vitro antitumor activity against four cancer cell lines (HT29, H460, A549 and MDA-MB-231). Most of them showed moderate to excellent activity against all the tested cell lines. Among them, compounds 20a-w with substituted benzyl-1H-indole moiety showed better selectivity against HT29 cancer cell line than other compounds. Compound 20d exhibited excellent antitumor activity with IC50 values of 0.024, 0.29, 0.84 and 0.88 μM against HT29, H460, A549 and MDA-MB-231, respectively. Further mechanism studies indicated that the marked pharmacological activity of compound 20d might be ascribed to activation of procaspase-3 (apoptosis-inducing) and cell cycle arrest, which had emerged as a lead for further structural modifications. Furthermore, 3D-QSAR model (training set: q(2) = 0.850, r(2) = 0.987, test set: r(2) = 0.811) was built to provide a comprehensive guide for further structural modification and optimization.

Design, synthesis and 3D-QSAR analysis of novel 2-hydrazinyl-4-morpholinothieno[3,2-d]pyrimidine derivatives as potential antitumor agents.

A series of 2-hydrazinyl-4-morpholinothieno[3,2-d]pyrimidine derivatives were synthesized and evaluated for their cytotoxic activities against five cancer cell lines. Most of them exhibited moderate to significant cytotoxic activities and high-selectivity against one or more cell lines, and nearly all of them had higher potency than positive controls against MDA-MB-231 cell line. The most promising compound 15f showed strong cytotoxic activities against H460, HT-29 and MDA-MB-231 cell lines, which were 1.7- to 66.5-folds more active than 2-(1H-Indazol-4-yl)-6-((4-(methylsulfonyl)-1-piperazinyl)methyl)-4-(4-morpholinyl)thieno[3,2-d]pyrimidine(GDC-0941). To investigate the SARs of thieno[3,2-d]pyrimidine derivatives in more details, CoMFA (q(2) = 0.436, r(2) = 0.937) and CoMSIA (q(2) = 0.706, r(2) = 0.947) models on H460 cell line were established. The generated 3D-QSAR models can be used for further rational design of novel thienopyrimidines as highly potent and selective cytotoxic agents.

Design, Synthesis and Evaluation of Novel Rhodanine-containing Sorafenib Analogs as Potential Antitumor Agents

A series of rhodanine‐containing sorafenib analogs was designed, synthesized and evaluated for their in‐vitro antitumor activity against three cancer cell lines (A549, H460 and HT29). Pharmacological data indicated that some of the target compounds possessed marked antiproliferative activity superior to the reference drug sorafenib, especially the most promising compound 7r (with the IC50 value of 0.8, 1.3 and 2.8 µM against A549, H460 and HT29 cell lines, respectively). The activity was found to strongly depend on the substitution pattern of the rhodanine motif at C‐5″ position. Results suggested that this series of compounds could serve as the bases for the development of novel antitumor agents.

Synthesis and anti-HBV activities evaluation of new ethyl 8-imidazolylmethyl-7-hydroxyquinoline-3-carboxylate derivatives in vitro.

Some new ethyl 8‐imidazolylmethyl‐7‐hydroxyquinoline‐3‐carboxylate derivatives have been synthesized and evaluated for their anti‐hepatitis B virus (HBV) activities and cytotoxicities in HepG2.2.15 cells stable transfection with HBV. Compounds 13a, 11b, 11c, 12c, 13c, 11g, and 12g inhibited the expression of the viral antigens HBsAg or HBeAg in a low concentration, of which 11c (IC50 = 12.6 μM, SI = 12.4), 12c (IC50 = 3.5 μM, SI = 37.9), and 12g (IC50 = 2.6 μM, SI = 61.6) showed more active abilities to inhibit the replication of HBV DNA than the positive control lamivudine (3TC, IC50 = 343.2 μM, SI = 7.0).

Discovery of Hybrid Dual N-Acylhydrazone and Diaryl Urea Derivatives as Potent Antitumor Agents: Design, Synthesis and Cytotoxicity Evaluation

Based on the hybrid pharmacophore design concept, a novel series of dual diaryl urea and N-acylhydrazone derivatives were synthesized and evaluated for their in vitro cytotoxicity by the standard MTT assay. The pharmacological results indicated that most compounds exhibited moderate to excellent activity. Moreover, compound 2g showed the most potent cytotoxicity against HL-60, A549 and MDA-MB-231 cell lines, with IC50 values of 0.22, 0.34 and 0.41 μM, respectively, which was 3.8 to 22.5 times more active than the reference compounds sorafenib and PAC-1. The promising compound 2g thus emerges as a lead for further structural modifications.

Design, Synthesis and Antiproliferative Activity of Novel 2-Substituted-4-amino-6-halogenquinolines

Two series of novel 2-substituted-4-amino-6-halogenquinolines 8a–l and 13a–h were designed, synthesized and evaluated for their antiproliferative activity against H-460, HT-29, HepG2 and SGC-7901 cancer cell lines in vitro. The pharmacological results indicated that most compounds with 2-arylvinyl substituents exhibited good to excellent antiproliferative activity. Among them, compound 8e was a considered promising lead for further structural modifications with IC50 values of 0.03 μM, 0.55 μM, 0.33 μM and 1.24 μM, which was 2.5- to 186-fold more active than gefitinib and compound 1.

Synthesis and biological evaluation of novel 2-(2-arylmethylene)hydrazinyl-4-aminoquinazoline derivatives as potent antitumor agents.

Two series of novel 2-(2-arylmethylene)hydrazinyl-4-aminoquinazoline derivatives were synthesized and evaluated for their cytotoxicity against H-460, HT-29, HepG2 and SGC-7901 cancer cell lines in vitro. Most compounds displayed moderate to excellent activity, with IC(50) values ranging from 0.015 to 4.09 μM against all tested cell lines, respectively. The most promising compound 9p (E)-2-(2-((1-(2,3-dichlorobenzyl)-1H-imidazol-2-yl)methylene)hydrazinyl)-N-(1-methylpiperidin-4-yl)quinazolin-4-amine with IC(50) values of 0.031 μM, 0.015 μM, 0.53 μM and 0.58 μM, which was 4- to 224 times more active than references 10 and Iressa, had emerged as a lead for further structural modifications.