Mechanism of Apoptosis Induced by Ursolic Acid in Human Colon Carcinoma HT29 Cells

Ruan Honggang; Jiang Hua; Zhang Qiuping

Abstract：Objective To investigate mechanism of apoptosis induced by ursolic acid in human colon carcinoma HT29 cells. Methods The inhibitory effects of UA on proliferation and apoptosis of HT29 were evaluated by MTT and double dye experiment. Effects of UA on cell cycle and apoptosis rate were detected by flow cytometry(FCM). The expressions of cyt - c,caspase - 3 and Livin were assessed by Western blot(WB)after exposure to UA. Results UA inhibited HT29 proliferation in a time - and dose - dependent manner. Apoptosis characteristics changed after expo-sure to UA by fluorescence microscope after treated with UA. UA could block HT29 cycle in G1 phase by FCM analy-sis. Apoptosis rate and peak value raised gradually with increasing concentration of UA. The expression of Livin and caspase - 3 decreased,active fragments of caspase - 3 as well as expression of cyt - c increased gradually with increas-ing concentration of UA. Conclusion UA can inhibit the proliferation and induce apoptosis of HT29,the mechanisms of which are associated with activating apoptosis pathway of mitochondria and reduce the expression of Livin.