A new series of novel benzo[c]acridine-diones possessing pharmacophoric elements of antitubulins with central dihydropyridine bridge were designed and synthesized as potential anticancer agents and tubulin polymerization inhibitors. The cytotoxic activity of the synthesized compounds was evaluated against eight cancer cell lines including MCF-7, A2780, HeLa, HepG2, DU145, A549, PC3, and LNCAP cancer cells and normal cells human umbilical vein endothelial cell (HUVEC) through 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay, wherein β-lapachone and combretastatin A-4 were used as positive controls. Some of our compounds (4c and 4g) showed significant cytotoxic activity on cancer cells with IC50 values in the range of 5.23-24.32 μM. None of the synthesized compounds showed significant cytotoxicity on normal HUVEC cells. Among all investigated derivatives, compound 4g showed promising greater antiproliferative activity against all tested cancer cells with the highest sensitivity observed for the PC3 cell line. Results from the flow cytometry analysis of PC3 and MCF-7 cancer cells treated with 4g showed an induced cell-cycle arrest at G2/M, and therefore induced apoptosis which occurred at low concentration of test compound, whereas annexin V-FITC/propidium iodide staining assay in the aforementioned cancer cell lines treated with 4g showed that 4g can cause necrosis in PC3 and MCF-7 cancer cells at higher concentration. Compound 4g proved to be an inhibitor of tubulin polymerization in a mode similar to that of colchicine and in a dose-dependent manner. Molecular docking studies of 4g into the colchicine-binding site of tubulin exhibited a possible mode of interaction between this compound and tubulin.
Keywords: anticancer; apoptosis; benzo[c]acridine-diones; cytotoxic; lapachone; synthesis; tubulin inhibitor.
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