熊果酸诱导结肠癌HT-29细胞株凋亡的实验研究

目的探讨熊果酸诱导结肠癌HT-29细胞株凋亡的作用机制.方法用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SP法检测凋亡相关基因caspase-9, bax表达的变化.结果熊果酸在体外对HT-29细胞有中度增殖抑制效应,在熊果酸作用下,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.在HT-29细胞凋亡过程中,凋亡相关基因caspase-9和bax的表达依次增强.结论熊果酸在体外对HT-29细胞有诱导凋亡的作用.其作用机制可能是通过促进caspase-9的活化和bax的表达上调来实现.

Ursolic acid induced apoptosis in colorectal carcinoma HT-29 cells

Objective To study the antitumor effect of ursolic acid and its mechanism. Methods The human colorectal carcinoma HT-29 cells were treated with ursolic acid(UA). The inhibition of cells proliferation was examined by MTT method. Morphological study, TUNEL method and flow cytometry were used to detect apoptosis. The expression of apoptosis related gene caspase-9 and bax was detected using immunohistochemical method. Results UA inhibited the proliferation of HT-29 cells. HT-29 cells treated with UA were induced to apoptosis. The morphology of HT-29 cells were changed such as nuclear chromosomal condensation and segmentation. Sub-G_1 peak was found by flow cytometry. The expressions of caspase-9 and bax genes were enhanced. Conclusion Apoptosis of HT-29 cell is the key mechanism for ursolic acid's killing action in the treatment of up-regulation of bax and acitivation of caspase-9 may contribute to its effects.