中文摘要：

目的：探讨敲低PI3Kp85α表达对人乳腺癌细胞系MCF-7细胞生长的影响和机制。方法：用靶向PI3Kp85α的siRNA转染人乳腺癌细胞系MCF-7，使用Real—time PCR法鉴定转染PI3Kp85α表达水平；MTT法评价PI3Kp85α siRNA对乳腺癌细胞系MCF-7生长的影响；流式细胞术检测转染后细胞周期分布和凋亡；采用免疫荧光染色及Westernblot方法观察IA型PI3K／AKT通路主要成员的表达。结果：Real—time PCR结果显示PI3Kp85α siRNA转染导致PI3Kp85α表达下调；MTT结果显示PI3Kp85αsiRNA转染抑制肿瘤细胞生长；流式细胞术检测可见PI3Kp85αsiRNA转染组细胞周期存在GdG，期阻滞而且凋亡率显著高于对照组与空载体组（F=19．255，P=0．002）。结论：应用PI3Kp85αsiRNA转染人乳腺癌细胞系MCF-7细胞，可抑制其增殖和诱导细胞凋亡，因此PI3Kp85α可以作为人乳腺癌基因治疗的候选靶点。

英文摘要：

Objective： To study the effect of and possible mechanism of knockinng down PI3Kp85α using siRNA in MCF-7 human breast cancer cell line. Methods： Oligofectamine was used to transfect PI3Kp85α siRNA to knock down the PI3Kp85α expression level in MCF-7 human breast cancer cell line in vitro. Real-time PCR was conducted to detect the expression of PI3Kp85α. The effect of PI3Kp85α siRNA on the growth of MCF-7 cells was measured by MTT. The cell cycle distribution and cell apoptosis were detected by cell flow cytometry. Protein expression was evaluated by immunofluorescence staining and Western blot. Results： The expression of PI3Kp85α was knocked down with PI3Kp85α siRNA in MCF-7 cells. Cell growth was delayed in PI3Kp85αsiRNA-treated group. Conclusion： The suppressive effect of PI3Kp85αsiRNA on the growth of MCF-7 human breast cancer cell line is significant and PI3Kp85α could be a candidate for gene therapy for breast cancer.