The anti-proliferative inhibition of ellipticine in human breast mda-mb-231 cancer cells is through cell cycle arrest and apoptosis induction

Ellipticine, a cytotoxic plant alkaloid, is known to inhibit topoisomerase II. Here we report the mechanism of apoptosis induction and cell cycle arrest by ellipticine in human breast MDA-MB-231 cancer cells. Ellipticine treatment arrested MDA-MB-231 cells at the G(2)/M phase after 6 h of treatment. This effect was strongly associated with a concomitant decrease in the level of cyclin 131, Cdc25 and Cdc2, and increase in phospho-Cdc2 (Tyr15). In addition, ellipticine also induced apoptosis in MDA-MB-231 cells, as determined by using both DNA fragmentation and Annexin-V staining assay. Ellipticine increased the expression of Bax, but decreased the level of Bcl-2, Bcl-X-L and X-linked inhibitor of apoptosis protein (XIAP), and subsequently triggered the mitochondrial apoptotic pathway (release of cytochrome c, and activation of caspase-9 and -3). In addition, pre-treatment of cells with caspase-9 inhibitor inhibited ellipticine-induced cell proliferation and apoptosis, indicating that caspase-9 activation was involved in MDA-MB-231 cell apoptosis induced by ellipticine. Taken together, our study suggests that the inhibition of cell cycle progression signaling xand initiation of the mitochondrial apoptotic system may participate in the anti-proliferative activity of ellipticine in MDA-MB-231 cells.