miR-15a诱导人乳腺癌细胞MCF-7凋亡的作用机制

Effect of miR-15a on induction of apoptosis in breast cancer MCF-7 cells

目的探讨miR-15a在诱导乳腺癌细胞凋亡中的作用及机制。方法采用定量聚合酶链反应检测人乳腺上皮细胞株MCF-10A和乳腺癌细胞株MCF-7中miR-15a的表达水平。采用软件预测miR．15a的靶点，并通过荧光素酶报告基因系统验证。将miR-15a经脂质体法转染MCF-7细胞，采用Westernblot法检测Bcl-2蛋白的表达，并采用流式细胞术检测MCF-7细胞的凋亡率。结果miR-15a在乳腺癌细胞株MCF-7中的表达明显低于乳腺上皮细胞株MCF-10A（0．253：1，P〈0．0001）。miR-15a可显著抑制抗凋亡基因Bcl-23＇-UTR荧光素酶报告基因的表达（P〈0．05）。与未转染组（对照组）相比，miR-15a转染组MCF-7细胞中Bcl-2的表达水平显著下降，凋亡明显增加（P〈0．05）。结论miR-15a作为一个潜在的抑癌基因，可通过靶向于Bcl-2诱导乳腺癌细胞MCF-7发生凋亡，其可为乳腺癌的临床治疗提供新的靶点和理论依据。

Objective To investigate the effect and mechanism of miR-15a on the induction of apoptosis in breast cancer cells. Methods To detect the expression level of miR-15a in breast cancer cell line MCF-7 cells and human mammary gland epithelial cell line MCF-10A cells by quantitative PCR. The target point of MCF-7 was predicted by software and was validated by luciferase report gene system. MiR-15a was transfected into MCF-7 cells with liposomes. The expression of Bel-2 in MCF-7 cells was detected by Western blotting and the apoptosis rate of MCF-7 cells was detected by flow cytometry. Results The expression level of miR-15a in MCF-7 cells was lower than that in the MCF-IOA cells （ 0. 253 ： 1, P 〈 O. 0001 ）. The expression of MiR-15a was significantly inhibited by Bcl-2 （ P 〈 0.05 ）. Compared with the control, Bcl-2 expression was significantly decreased in the MCF-7 cells. The results of flow cytometry showed that the apoptosis rate was 13.4% in non-transfected MCF-7 cells, 15.9% in MCF-7 cells transfected with control RNA, and 31.5% in MCF-7 cells transfeeted with miR-15a （P 〈 0.05 ）, indicating an evident induction of apoptosis in the MCF-7 cells. Conclusion miR-15a may have a potential application value in breast carcinoma biotherapy.