Akt联合电离辐射对人乳腺癌MCF-7细胞凋亡、自噬和增殖的影响

目的: 通过检测Akt联合电离辐射对乳腺癌MCF-7细胞凋亡、自噬和增殖的影响,探讨以Akt为靶点的乳腺癌放射治疗作用。方法: 选择人乳腺癌MCF-7细胞、Akt过表达MCF-7(Akt-MCF-7)细胞和Akt低表达(Akt-RNAi-MCF-7) 细胞,实验分为MCF-7组、MCF-7+4 Gy组、Akt-MCF-7+4 Gy组和Akt-RNAi-MCF-7+ 4 Gy组 。3种细胞经4 Gy照射后,Western blotting法检测Akt蛋白表达,AnnexinⅤ-FITC和PI染色流式细胞术检测细胞凋亡率,MDC染色荧光显微镜观察细胞自噬百分比,MTT法检测细胞增殖活性。结果: 与MCF-7 细胞比较,Akt-MCF-7细胞中Akt蛋白表达强度增加,Akt-RNAi-MCF-7细胞中Akt蛋白表达强度降低。与MCF-7组比较,MCF-7+4 Gy、Akt-MCF-7+4 Gy和Akt-RNAi-MCF-7+4 Gy组细胞凋亡率和自噬百分比均明显增加(P<0.05或P<0.01),且以Akt-RNAi-MCF-7+4 Gy组增加最明显;与MCF-7+4 Gy组比较,Akt-MCF-7+4 Gy组细胞凋亡率和自噬百分比明显降低(P<0.05或P<0.01),而Akt-RNAi-MCF-7+4 Gy组细胞凋亡率和自噬百分比明显增加(P<0.05或P<0.01)。与MCF-7组比较,MCF-7+4 Gy组、Akt-MCF-7+4 Gy组和Akt-RNAi-MCF-7+4 Gy组细胞增殖活性在不同时间点均明显降低(P<0.05或P<0.01),Akt-RNAi-MCF-7+4 Gy组细胞增殖活性降至最低。与MCF-7+4 Gy组比较,Akt-MCF-7+4 Gy组细胞增殖活性在24 h时明显升高(P<0.05),而Akt-RNAi-MCF-7+4 Gy组细胞增殖活性在不同时间点均明显降低(P<0.01)。结论: Akt过表达可以显著降低电离辐射诱导的MCF-7细胞凋亡、自噬和增殖,而Akt低表达作用则相反。

Effects of Akt combined with ionizing radiation on apoptosis,autophagy and proliferation in breast cancer MCF-7 cells

Objective To measure the effects of Akt combined with ionizing radiation on the apoptosis, autophagy and proliferation in the breast cancer MCF-7 cells, and to explore the role of radiotherapy of breast cancer using Akt as a target. Methods The Akt protein expressions in MCF-7, Akt-MCF-7 (Akt over-expression) and Akt-RNAi-MCF-7 (Akt low-expression) cells were detected by Western blotting method after irradiated by 4 Gy X-rays, the apoptotic rates were measured by FCM with AnnexinⅤ-FITC and PI staining, the autopahgic cell percentages were measured by fluorescence microscope with MDC staining, and the cell proliferation activities were detected by MTT assay. Results Compared with MCF-7 cells, the Akt protein expression in Akt-MCF-7 cells was increased, but it was decreased in Akt-RNAi-MCF-7 cells. Compared with MCF-7 group, the apoptotic rates and autophagic percentages in MCF-7+4 Gy, Akt-MCF-7+4 Gy and Akt-RNAi-MCF-7+4 Gy groups were increased significantly (P<0.05 or P<0.01), especially in Akt-RNAi-MCF-7+4 Gy group; compared with MCF-7+4 Gy group, the apoptotic rate and autophagic percentage in Akt-MCF-7+4 Gy group were decreased significantly (P<0.05 or P<0.01), but they were increased significantly in Akt-RNAi-MCF-7+4 Gy group (P<0.05 or P<0.01).Compared with MCF-7 group, the cell proliferation activities in MCF-7+4 Gy group, Akt-MCF-7+4 Gy group and Akt-RNAi-MCF-7+4 Gy group were significantly decreased at different time points(P<0.05 or P<0.01), especially in Akt-RNAi-MCF-7+4 Gy group.Compared decreased with MCF-7+4 Gy group, the cell proliferation activity in Akt-MCF-7+4 Gy group was significantly increased at 24 h (P<0.05), while the cell proliferation activities in Akt-RNAi-MCF-7+4 Gy group were significantly decreased at different time points (P<0.01). Conclusion Akt over-expression can significantly reduce the apoptosis, autophagy and proliferation in MCF-7 cells induced by ionizing radiation, but Akt low-expression has opposite role.