[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.