二氢青蒿素通过PTEN/PI3K/Akt通路抑制胃癌细胞的增殖

DHA-inhibited proliferation through the PTEN/PI3K/Akt pathway in gastric cancer SGC7901 cells

目的:探讨二氢青蒿素(dihydroartemisinin,DHA)通过PTEN/PI3K/Akt通路对人胃癌细胞株SGC7901细胞周期的影响及其分子机制。方法:不同浓度(6.25、12.5、25、50、100μmol/L)DHA作用SGC7901细胞24、48、72h后,细胞计数法检测SGC7901细胞增殖的情况。不同浓度DHA作用SGC7901细胞24 h后,流式细胞术测定细胞周期的分布;RT-PCR和Western blotting分别测定cyclin D1、P27的mRNA和蛋白的表达水平;Western blotting测定PTEN、PI3K、p-Akt的表达水平。分别以PTEN特异性小干扰RNA(PTEN-siRNA)及无关序列对照siRNA(non-specific siRNA,NS-siRNA)转染细胞,加入100μmol/L DHA,作用SGC7901细胞24 h后,Western blotting测定cyclin D1、P27、PTEN、PI3K、p-Akt的表达水平。结果:DHA剂量和时间依赖性抑制SGC7901细胞的增殖,使细胞周期阻滞于G1期(P<0.05)。RT-PCR和Western blotting分析结果显示,100μmol/L DHA作用SGC7901细胞24 h后,cyclin D1 mRNA和蛋白表达显著下降,P27 mRNA和蛋白表达显著上升(P<0.05)。PTEN的蛋白表达显著增加,PI3K和p-Akt的表达水平逐渐下降(P<0.05)。敲低PTEN表达后,DHA对PI3K和p-Akt的表达水平的影响明显减弱,与此同时,cyclin D1表达水平升高,P27表达有所下降(P<0.05)。结论:DHA通过抑制PTEN/PI3K/Akt信号通路的活化,影响细胞增殖相关基因cyclin D1和P27的表达,进而使细胞阻滞于G0/G1期,抑制人胃癌SGC7901细胞的增殖。

Objective： This study aims to elucidate the mechanism of anti-proliferation induced by dihydroartemisinin （DHA） on human gastric cancer SGC7901 cells through the PTEN/PI3K/Akt pathway. Methods： SGC7901 cells were treated with DHA at various concentrations （6.25, 12.5, 25, 50, and 100 pmol/L） in different lengths of time （24, 48, and 72 h）. We detected the changes in proliferation through cell count. The cell cycles were measured through flow cytometry. The cells were treated with 100 gmol/L DHA and were cultured for 24 h. The expressions of cyclin D 1 and P27 were detected through reverse transcription-polymerase chain reaction and Western blot analysis, respectively. The expressions of PTEN, PI3K, and p - Akt were also detected through Western blot analysis. The PTEN expression was downregulated by the RNAi technology. The cells were subsequently treated with 100 gmoFL DHA for 24 h, followed by a Western blot analysis for the expressions ofPTEN, PI3K, p Akt, cyclin D1, and P27. Results： Results of the cell count showed that DHA greatly inhibited the growth and proliferation of SGC7901 cells in a dose- and time- dependent manner （P〈0.05）. The DHA inhibited the proliferation of SGC7901 cells through the induced cell cycle G1 phrase arrest. The expressions of cyclin D1, PI3K, and p - Akt were downregulated, and the expressions of P27 and PTEN were upregulated after DHA treatment （P〈0.05）. The DHA-elicited decrease in cyclin D1, PI3K, and p-Akt expression was significantly induced, and the DHA-elicited increase in P27 and PTEN expression was significantly reduced （P〈0.05） when the SGC7901 cells were transfected with PTEN-specific siRNA to block the endogenous PTEN expression induced by DHA. Conclusion： DHA induces the cell cycle G0/G, phase arrest through the regulation of cyclin D1 and P27 expression by activating the PTEN/ PI3K/Akt signaling pathway in human gastric cancer SGC7901 cells.