目的探讨熊果酸(urso lic ac id,UA)体外抑制胃癌细胞SGC 7901生长的作用机制。方法体外培养人胃癌细胞株SGC 7901,M TT法观察不同浓度UA作用不同时间对细胞生长的影响;不同浓度UA(0~40μmol/L)处理SGC 7901细胞24 h后,倒置显微镜观察细胞形态变化;荧光染料Hoechst 33258染色和流式细胞仪检测细胞凋亡情况;W estern B lotting法检测凋亡相关蛋白Bcl-2和Bax的表达。结果20~40μmol/L UA可抑制SGC 7901的生长,并呈浓度和时间依赖性,其作用12、24、36、48 h的IC₅₀分别为(57. 50±1. 18)、(34. 28±2. 05)、(27. 54±1. 11)、(24. 83±1. 02)μm o l/L。20~40μmol/L UA作用24 h后,SGC 7901细胞变圆,出现不同程度的漂浮;同时细胞被阻滞于G₀/G₁期并发生凋亡,随药物浓度升高,凋亡率增加,凋亡相关蛋白B cl-2表达减少,Bax无明显变化。结论熊果酸对SGC 7901细胞具有较强的抗肿瘤活性,其机制可能与细胞毒作用、增殖抑制作用以及下调凋亡相关蛋白Bcl-2表达而促进凋亡有关。

Objective To investigate the potential mechanism of inhibition of ursolic acid(UA)on growth of human gastric cancer cell Iines SGC7901 in vitro. Methods SGC7901 cells were cultured in vitro, MTT assay was used to observe the effect of UA on growth of SGC7901 cells in various concentrations for different times. After SGC7901 cells were treated by 0-40 μmol/L UA for 24 h. morphological changes were observed by inverted microscope. Apoptotic changes were detected by fluorescence microscopy and flow cytometry(FCM). Protein expressions of Bcl-2 and Bax were determined by Western blotting. Results UA(20-40 μmol/L)could significantly inhibit the growth of SGC7901 cells in a dose-and time-dependent manner,the IC₅₀ value of UA for SGC7901 c,ells for 12,24,36,and 48 h were(57. 50±1. 18),(34. 28土2. 05),(27. 54±1. 11),and(24. 83土1. 02)μmol/L,respectively. After UA(20-40μmol/L)treatment for 24 h,SGC7901 cells turned round and floated at different levels;SGC7901 cells were arrested at G₀/G_l phase and apoptosis was induced,and the apoptotic rate was increased along with the increase of UA concentration. Meanwhile Bcl-2 protein expression decreased,whereas Bax prorein expression unchanged. Conclusion UA has a stronger antitumor effect on SGC7901 cells. Cytotoxic effect,proliferation inhibition,and apoptosis may be involoved in the mechanism of UA,and the apoptosis caused bv UA may be enhanced by decrease of Bcl-2 protein expression.

湖北省教育厅基金资助项目(2001A14012)