3‐ O ‐Acetyloleanolic Acid Induces Apoptosis in Human Colon Carcinoma Hct‐116 Cells

The cytotoxic effect of 3‐ O ‐acetyloleanolic acid, an oleanolic acid derivative isolated from the seeds of Vigna sinensis K., was investigated in human colon carcinoma HCT‐116 cells. 3‐ O ‐acetyloleanolic acid dose‐dependently inhibited the viability of HCT‐116 cells. Apoptosis was characterized by detection of cell surface annexin V and sub‐G1 apoptotic cell populations. The number of immunostained cells with annexin V‐FITC was increased after treatment with 3‐ O ‐acetyloleanolic acid. The sub‐G1 cell population was also increased. Expression of TRAIL‐mediated apoptosis signaling‐related death receptor DR5 was increased in 3‐ O ‐acetyloleanolic acid‐treated HCT‐116 cells. Activation of caspase‐8 and caspase‐3, critical mediators of extrinsic apoptosis signaling, was also increased by 3‐ O ‐acetyloleanolic acid. The results indicate that 3‐ O ‐acetyloleanolic acid induces apoptosis in HCT‐116 cells mediated by an extrinsic apoptosis signaling cascade via up‐regulation of DR5. Copyright © 2012 John Wiley & Sons, Ltd.