[Ursolic acid induces apoptosis in colon cancer HT-29 cells]

Abstract

Objective: To study the antitumor effects of ursolic acid and mechanisms of its action.

Methods: The cells of human colorectal carcinoma cell line HT-29 were treated with ursolic acid at different concentration. The proliferation inhibition was examined by MTT assay. Morphological examination, TUNEL method and flow cytometry were used to detect apoptosis. Immunohistochemical method was used to detect the expression of apoptosis related genes caspase-9 and bcl-2. The semi-quantification of protein expression was analyzed by pathological image-analysis.

Results: UA inhibited the proliferation of HT-29 cells moderately. Apoptosis of HT-29 cells was induced by ursolic acid treatment. The morphology of HT-29 showed changes such as nuclear chromatin condensation and fragmentation. Sub-G(1) peak was found by flow cytometry. The maximal apoptosis rate was 11.63%. The expression of caspase-9 gene was enhanced. The expression of bcl-2 gene was decreased. All these effects were in a dose-dependent and time-depend manner.

Conclusion: Apoptosis in colon cancer HT-29 cells is one of the key mechanisms of ursolic acid action and its antitumor activity may be applicable for the treatment of cancers.