线粒体融合素基因-2对人乳腺癌MCF-7细胞株增殖与化疗敏感性的影响

背景与目的:线粒体融合素基因-2(mitofusin-2 gene,mfn2)是作用于线粒体外膜的一种增殖抑制基因,mfn2过表达可抑制血管平滑肌细胞的增殖.本研究探讨外源性mfn2对人乳腺癌细胞MCF-7增殖以及化疗敏感性的影响.方法:将含有mfn2 cDNA的质粒在阳离子聚合物的介导下体外转染MCF-7细胞,Western blot法检测绿色荧光蛋白(green fluorescent protein,GFP)的表达,细胞计数及MTT法检测mfn2对MCF-7细胞增殖的影响,流式细胞术检测MCF-7细胞周期分布及喜树碱处理前后细胞凋亡的变化.结果:转染mfn2基因的MCF-7细胞可以稳定高表达GFP.MTT实验提示转染mfn2 cDNA后,MCF-7细胞增殖明显受到抑制,DNA直方图显示细胞停滞于S期,转染mfn2 cDNA组S期细胞比率为(42.7±1.3)%,高于转染空质粒组的(17.2 2.0)%和空白对照组的(19.6±1.7)%(P＜0.05).mfn2基因转染后诱导的细胞凋亡率从(3.6±0.6)%升高到(16.0±0.3)%;加入喜树碱4 h后转染mfn2基因的细胞凋亡率为(69.6 4.3)%,高于转染空质粒组的(31.0±1.8)%和空白对照组的(23.4 2.8)%(P＜0.05).结论:转染mfn2基因可以明显抑制MCF-7细胞的增殖,增强MCF-7细胞对喜树碱的敏感性.

Effects of mitofusin-2 gene on proliferation and chemosensitivity of human breast carcinoma cell line MCF-7

BACKGROUND & OBJECTIVE: Mitofusin-2(mfn2), a proliferation-inhibiting gene, targets to the outer membrane of mitochondria. Its overexpression suppresses the proliferation of vascular smooth muscle cells. This study was to explore the effects of mfn2 gene on the proliferation and chemosensitivity of human breast carcinoma cell line MCF-7. METHODS: Plasmid pEGFP-mfn2 containing mfn2 cDNA was constructed and transfected into MCF-7 cells by sofast. The expression of green fluorescent protein (GFP) in MCF-7 cells was detected by Western blot. Cell proliferation was measured by MTT assay and cell counting. Cell cycle and chemosensitivity of MCF-7 cells to camptothecin (CAM) was observed by flow cytometry (FCM). RESULTS: After transfection of pEGFP-mfn2, the stable expression of GFP protein was detected in MCF-7 cells, and cell cycle was arrested: the S phase proportion was significantly higher in pEGFP-mfn2-transfected cells than in pEGFP-transfected and untransfected cells [(42.7+/-1.3)% vs. (17.2+/-2.0)% and (19.6+/-1.7)%, P<0.05]. The apoptosis rate were significantly higher in pEGFP-mfn2-transfected cells than in pEGFP-transfected and untransfected cells [(16.0+/-0.3)% vs. (4.5+/-0.9)% and (3.6+/-0.6)% before treatment of CAM, P<0.05; (69.6+/-4.3)% vs. (31.0+/-1.8)% and (23.4+/-2.8)% after 4-hour treatment of CAM, P<0.05]. CONCLUSION: mfn2 gene can inhibit the proliferation of MCF-7 cells and increase their chemosensitivity to CAM.