Discovery of novel 2-substituted 2, 3-dihydroquinazolin-4(1H)-one derivatives as tubulin polymerization inhibitors for anticancer therapy: The in vitro and in vivo biological evaluation.

A series of novel 2-substituted 2, 3-dihydroquinazolin-4(1H)-one derivatives were designed, synthesized and estimated for their in vitro antiproliferative activities against HepG2, U251, PANC-1, A549 and A375 cell lines. Among them, compound 32 was the most promising candidate, and displayed strong broad-spectrum anticancer activity. The mechanism studies revealed that compound 32 inhibited tubulin polymerization in vitro, disrupted cell microtubule networks, arrested the cell cycle at G2/M phase, and induced apoptosis by up-regulating the expression of cleaved PARP-1 and caspase-3. Furthermore, molecular docking analysis suggested that compound 32 well occupied the binding site of tubulin. In addition, compound 32 exhibited no significant activity against 30 different kinases respectively, indicating considerable selectivity. Moreover, compound 32 significantly inhibited the tumour growth of the HepG2 xenograft in a nude mouse model by oral gavage without apparent toxicity. These results demonstrated that some 2-substituted 2, 3- dihydroquinazolin-4(1H)-one derivatives bearing phenyl, biphenyl, naphthyl or indolyl side chain at C-position might be potentially novel antitumor agents as tubulin polymerization inhibitors.