Objective To study the mechanism of 18β-GA induced 17(i-HSD3 expression inhibition and cell apoptosis in androgen-de-pendence prostate cancer cell line LNCaP. Methods Cell proliferation rate of LNCaP cells exposed to different concentrations of 18p-GA was detected in order to determine the optimum concentration of the reagent and time and (lose dependency; the expression of ATF4 and eIF2α was detected by Western blot;the level of 17βHSD3 mRNA was evaluated by Real-time qPCR;the function of eIF2α was determined by knock-down with siRNA. Results MIT assay showed that absorbanee value at 0D4sllll was significantly reduced at the 18β-GA concentration of 8 μmol/L,and the difference was statistically significant (F< 0.05);Western blot showed that 18β-GA promoted the expression of ATF4 and elF2α;real-time qPCR results indicated that 18β-GA inhibited the transcription of l7βHSD3 mRNA via phosphoryla-tion of eIF2α. Conclusion 18β-GA inhibited the expression of 17βHSD3 mRNA and induced the apoptosis in androgen-dependence of prostate cancer cell line LNCaP, resulting in suppressing tumor growth.%目的 探讨18β甘草次酸(18β-GA)对17β羟基类固醇脱氢酶Ⅲ(17βHSD3)表达的抑制作用及诱导雄性激素依靠性前列腺癌细胞株LNCaP凋亡的作用机制.方法 采用MTT法检测给予不同浓度18β-GA的LNCaP细胞的增殖率以确定其最佳作用浓度、时间及与剂量的依赖关系；采用Western blot检测真核启动因子2α(p-eIF2α)及活化转录因子4(ATF4)蛋白的表达；采用Real-time qPCR方法检测17βHSD3 mRNA的变化情况；用siRNA干扰eIF2α mRNA的表达从而确定eIF2α的作用.结果 MTT结果显示:18β-GA浓度为8μmol/L时OD45nm处吸光值明显减低,与对照组相比差异有统计学意义(P＜0.05). Westernblot结果显示:18β-GA对p-eIF2α及ATF4的表达具有促进作用.Real-time qPCR结果显示:18β-GA对17βHSD3 mRNA的转录具有抑制作用.结论 18β-GA通过激活eIF2α抑制17βHSD3的表达,并诱导LNCaP细胞株的凋亡,从而抑制肿瘤生长.
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