Mitofusin-2 Triggers Cervical Carcinoma Cell Hela Apoptosis via Mitochondrial Pathway in Mouse Model.

BACKGROUND/AIMS: Cervical carcinoma continues to be one of the most dangerous cancer types, and more effective therapies are urgently needed for cervical carcinoma treatment. Mitochondria-associated Mitofusin 2 has influence on the progression of many cancers. In the current study, we aimed to focus on the cell apoptotic effects of Mfn2 on cervical carcinoma HeLa cells in vitro and to try to explore its underlying mechanisms. Moreover, we investigated the anticancer potential of Mfn2 in a cervical carcinoma mouse model.

METHODS

Adenovirus-Mfn2 (Adv-Mfn2) was used to deliver mfn2 into HeLa cells and tumour tissues in a nude mouse model. CCK-8, TUNEL assay, Western blot and immunohistochemical staining were performed to detect the effects of Mfn2. The mRNA level of Mfn2 was determined by quantitative realtime PCR (qRT-PCR) analysis. The effect of Mfn2 on cell apoptosis was investigated by flow cytometry. Flow cytometry was used to assess the change of the mitochondrial membrane potential of the cells treated with JC-1 assay. Mfn2, Bax, Bcl-2, cytochrome c, cleaved caspase-3, and cleaved caspase-9 protein levels were analysed by Western blot.

RESULTS

Data from CCK-8 and flow cytometry showed that Mfn2 could inhibit proliferation and induce apoptosis in a dose- and time-dependent manner in HeLa cells. JC-1 test results revealed that the membrane potential of the mitochondrial decreased in a dose-dependent manner in HeLa cells after Adv-Mfn2 treatment. The data from Western blot confirmed that higher cytosolic amounts of cytochrome c with increasing doses of Adv-Mfn2 signified the onset of the intrinsic apoptotic pathway. Levels of cleaved caspase-3 and cleaved caspase-9 increased in HeLa cells with Adv-Mfn2 treatment. We also found significant increases in the Bax level and a decreased Bcl-2 level with Adv-Mfn2 treatment. We further confirmed that Mfn2 could significantly inhibit the growth of the cervical tumour in the xenografted cervical carcinoma mouse model. After a 9-day-treatment, the tumours of the Adv-mfn2 group were inhibited and induced into apoptosis. The results demonstrated that the overexpression of Mfn2 could not only increase the levels of Bax and Bid in cervical tumour cells but also decrease the phosphorylation of Bad and the expression of Bcl-2.

CONCLUSION

These studies suggested that the overexpression of Mfn2 could trigger cervical tumour apoptosis in vitro and in vivo, which was related to the mitochondrial pathway, and may provide a new treatment target for cervical carcinoma.