18β甘草次酸对17β羟基类固醇脱氢酶Ⅲ表达的抑制及诱导前列腺癌细胞LNCaP凋亡的研究

18β-glycyrrhetinic Acid Inhibit Human 17β-hydroxysteroid Dehydrogenase Type Ⅲ and Induce Cell Apoptosis via Activation of eIF2α in Prostate Cancer

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eIF2αmRNA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OD450 nm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。

Objective To study the mechanism of 18β-GA induced 17β-HSD3 expression inhibition and cell apoptosis in androgen-dependence prostate cancer cell line LNCaP.Methods Cell proliferation rate of LNCaP cells exposed to different concentrations of 18β-GA was detected in order to determine the optimum concentration of the reagent and time and dose 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 MTT assay showed that absorbance value at OD450nm was significantly reduced at the 18β-GA concentration of 8 μmol/L,and the difference was statistically significant（P 0.05）;Western blot showed that 18β-GA promoted the expression of ATF4 and eIF2α;real-time qPCR results indicated that 18β-GA inhibited the transcription of 17βHSD3 mRNA via phosphorylation 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.