Silencing MFN2 Drives WNT/β-catenin Nucleation to Reduce Sorafenib Sensitivity in Hepatocellular Carcinoma Cells.

Objective: Mitofusin-2 (MFN2) is a mitochondrial membrane protein that plays a critical role in regulating mitochondrial fusion and cellular metabolism. To further elucidate the impact of MFN2, this study aimed to investigate its significance on hepatocellular carcinoma (HCC) cell function and its potential role in mediating chemosensitivity.

Methods: This study investigated the effects of silencing and overexpressing MFN2 on the survival, proliferation, invasion and migration abilities, and sorafenib resistance of MHCC97-L HCC cells. Additional experiments were conducted using XAV939 (a β-catenin inhibitor) and HLY78 (a β-catenin activator) to further validate these findings.

Results: Silencing MFN2 significantly promoted the survival and proliferation of MHCC97-L cells, enhanced their invasion and migration capacities, increased the IC₅₀ of sorafenib, reduced the percentage of TUNEL-positive cells, and decreased the expression of proapoptotic proteins. Additionally, silencing MFN2 markedly induced the nuclear translocation of β-catenin, increased β-catenin acetylation levels and enhanced the expression of the downstream regulatory proteins Snail1 and Vimentin while inhibiting E-cadherin expression. Conversely, overexpressing MFN2 reversed the effects observed in MHCC97-L cells mentioned above. The results confirmed that silencing MFN2 activated the β-catenin/epithelial-mesenchymal transition (EMT) pathway and reduced the sensitivity of cells to sorafenib, which could be reversed by XAV939 treatment. Conversely, overexpression of MFN2 inhibited the β-catenin/EMT pathway and increased the sensitivity of cells to sorafenib, which could be altered by HLY78.

Conclusion: Low expression of MFN2 in HCC cells promotes the nuclear translocation of β-catenin, thereby activating the EMT pathway and mediating resistance to sorafenib.