Abstract
Background Mitofusin 2 (MFN2) is localized on the outer membrane of mitochondria and is closely related to the migration of malignant tumor cells. Estrogen receptor β (ERβ) plays an anticancer role in breast cancer. Our previous experiments showed that ERβ can induce MFN2 expression, which then inhibits breast cancer cell migration. However, the exact mechanism by which ERβ-induced MFN2 inhibits breast cancer cell migration is unknown. Methods In this study, immunohistochemistry was first used to detect the expression of MFN2 in breast cancer tissues, and its relationship with the clinicopathological characteristics and prognosis of breast cancer patients was analyzed. MCF-7 and MDA-MB-231 cells were transfected with ERβ and MFN2 knockdown or expression plasmids. Western blot was used to detect the effects of ERβ on MFN2 and MFN2 on P-AKT473 and MMP2; the P-AKT pathway inhibitor LY294002 was administered to cells transfected with MFN2 knockdown plasmids, Western blot, immunocytofluorescence, and a wound healing assay revealed the effect of MFN2 on its downstream signaling pathway and the migration of breast cancer cells. Results This study found that the expression of MFN2 is related to the molecular type and prognosis of breast cancer patients ( P <0.05). The positive expression rate of MFN2 in triple-negative breast cancer was significantly lower than that in the HER2 + and luminal types. However, MFN2 expression was unrelated to age, tumor size, lymph node metastasis, TNM stage, histological type and grade ( P >0.05); ERβ positively regulated MFN2 expression and reduced the migration of both MCF-7 and MDA-MB-231 cells, while MFN2 knockdown increased the expression of P-AKT473 and MMP2. In contrast, the overexpression of MFN2 inhibited the expression of P-AKT473 and MMP2. These results showed that in MFN2 knockdown cells treated with LY294002, P-AKT473 and MMP2 expression levels were reversed. The reversal of P-AKT473 and MMP2 expression levels inhibits the invasiveness of human breast cancer cells. Conclusion MFN2 is related to the molecular subtype and prognosis of breast cancer. In human breast cancer MCF-7 and MDA-MB-231 cells, ERβ-induced MFN2 can inhibit the P-AKT pathway, which inhibits the invasiveness and migration of both breast cancer cell lines.
α-Actinin-4 confers radioresistance coupled invasiveness in breast cancer cells through AKT pathway
