Design, synthesis and molecular modeling of pyrazoline based coumarin derivatives as tubulin polymerization inhibitors

A series of coumarin-pyrazoline hybrids was synthesized by cyclization of the coumarin chalcones with hydrazine hydrate and phenyl hydrazine through 1,4-addition on alpha,(3-unsaturated carbonyl system. The synthesized derivatives were evaluated for their cytotoxicity against HCT116, MCF7 and BJ-1 cell lines. Among them, compounds 5d and 5f showed the best selectivity indices (IC50= 13.2 and 12.3 mu M (HCT116), 5.0 and 5.5 mu M (MCF7) and 26.2 and 26.5 mu M (BJ-1), respectively). Derivative 5d revealed an inhibitory effect on tubulin assembly (IC50= 6.53 mu M), and CDK2 activity (IC50= 0.47 mu M). Induction of apoptosis was observed in MCF-7 cells after treatment with derivative 5d which was associated with a significant decrease in Bcl-2 level and 3-fold increase in Bax level. Moreover, derivative 5d revealed an anti-migration activity as detected by wound healing assay. The active compound 5d was docked within the (3 tubulin active site to investigate the protein-ligand interactions illustrating a unique binding mode with better score than colchicine (-8.5 kcal/mol). Those studies, along with pharmacokinetics predictions, provided a base for further optimization of compound 5d as a potential anti-tubulin agent.