熊果酸对结肠癌细胞作用机制的初步研究

目的:探讨熊果酸对结肠癌细胞株HT-29凋亡的作用机制。方法:不同浓度的熊果酸处理HT-29细胞,采用四甲基偶氮唑蓝(MTT)比色检测熊果酸对HT-29细胞的增殖抑制效应,采用形态学、TUNEL法、流式细胞术检测细胞凋亡的发生,应用免疫组织化学法检测凋亡相关基因caspase-9,bax表达的变化。结果:熊果酸对HT-29细胞有中度增殖抑制效应,HT-29细胞出现显著的细胞凋亡征象:TUNEL显示细胞固缩,核染色质聚集或断裂,形成凋亡小体。流式细胞术检测在G1期之前出现sub-G1峰,凋亡率最高为11.63%,熊果酸的作用具有浓度和时间依赖性。细胞凋亡过程中,凋亡相关基因caspase-9和bax的表达逐渐增强。结论:熊果酸通过促进caspase-9的活化、上调bax的表达,对HT-29细胞具有凋亡的作用。

An Experimental Study on Ursolic Acid Induced Apoptosis in HT-29 Cells

Objective: To determinate whether ursolic acid (UA) could induce apoptosis in human colorectal carcinoma HT-29 cell line and its mechanism. Methods: The human colorectal carcinoma HT-29 cells were treated with ursolic acid. The proliferation inhibitory was examined by MTT method. Morphological study, TUNEL method and flow cytometry were used to detect apoptosis. Immuohistochemical method was assayed to detect the expression of apoptosis related gene caspase-9 and bax. Results: UA inhibited the proliferation of HT-29 cells, and HT-29 cells treated with ursolic acid were induced to apoptosis. The morphologic changes of HT-29 cells were nuclear chromosomal condensation and segmentation. Sub-G_1 peak was found by flow cytometry. The expression of caspase-9 and bax gene was enhanced. Conclusion: Apoptosis of HT-29 cell is the key mechanism for ursolic acid’s killing action in the treatment of cancer. Up-regulation of Bax and acitivation of caspase-9 may contribute to its effects.