Ophiopogonin D inhibits cell proliferation, causes cell cycle arrest at G(2)/M, and induces apoptosis in human breast carcinoma MCF-7 cells

OBJECTIVE: To investigate the effects of ophiopogonin D on human breast cancer MCF-7 cells. METHODS: Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and colony formation experiments. Cell cycle was measured with cell cycle flow cytometry and a living cell assay. Apoptosis and terminal deoxynucleoitidyl transferase-mediated dUTP nick end labeling assays were performed to detect the apoptosis of MCF-7 cells induced by ophiopogonin D. Finally, Western blotting was used to explore the mechanism. RESULTS: Exposure of cells to ophiopogonin D resulted in marked decreases in viable cells and colony formation with a dose-dependent manner. Treatment of these cells with ophiopogonin D also resulted in cell cycle arrest at the G(2)/M phase, and increased apoptosis. Mechanistically, ophiopogonin D-induced G(2)/M cell cycle arrest was associated with down-regulation of cyclin B1. Furthermore, activation of caspase-8 and caspase-9 was involved in ophiopogonin D-induced apoptosis. CONCLUSION: The data suggested that ophiopogonin D inhibits MCF-7 cell growth via the induction of cell cycle arrest at the G(2)/M phase.