Design, synthesis, molecular modeling, and biological evaluation of pyrazole-naphthalene derivatives as potential anticancer agents on MCF-7 breast cancer cells by inhibiting tubulin polymerization

A new series of pyrazole-naphthalene derivatives (5a-5q) have been synthesized and evaluated for their anticancer activity against human breast cancer cell lines (MCF-7). Most of newly synthesized compounds (except 5i, 5m, and 5p) exhibited potent antiproliferative activity in the range of IC50 = 2.78 +/- 0.24 mu M - 9.13 +/- 0.47 mu M. Among them, compound 5j (IC50 = 2.78 +/- 0.24 mu M), bearing ethoxy at the 4-position of the phenyl ring, was found to be the most active compound in this series of compounds, with five folds more active than the standard drug cisplatin (IC50 = 15.24 +/- 1.27 mu M). In addition, compound 5j and colchicine showed the same ability to inhibit tubulin polymerization with the IC50 values of 4.6 mu M and 6.7 mu M, respectively. Cellular mechanism studies elucidated that compound 5j arrested the cell cycle at G2/M phase and induced apoptosis. Furthermore, molecular docking analysis revealed that compound 5j formed stable interactions in the colchicine-binding site of tubulin.