Additional Inhibition Of Wnt/Beta-Catenin Signaling By Metformin In Daa Treatments As A Novel Therapeutic Strategy For Hcv-Infected Patients

Chronic hepatitis C virus (HCV) infection causes hepatocellular carcinoma (HCC). Although HCV clearance has been improved by the advent of direct-acting antiviral agents (DAA), retrospective studies have shown that the risk of subsequent HCC, while considerably decreased compared with active HCV infection, persists after DAA regimens. However, either the mechanisms of how chronic HCV infection causes HCC or the factors responsible for HCC development after viral eradication in patients with DAA treatments remain elusive. We reported an in vitro model of chronic HCV infection and determined Wnt/beta-catenin signaling activation due to the inhibition of GSK-3 beta activity via serine 9 phosphorylation (p-ser9-GSK-3 beta) leading to stable non-phosphorylated beta-catenin. Immunohistochemical staining demonstrated the upregulation of both beta-catenin and p-Ser9-GSK-3 beta in HCV-induced HCC tissues. Chronic HCV infection increased proliferation and colony-forming ability, but knockdown of beta-catenin decreased proliferation and increased apoptosis. Unexpectedly, Wnt/beta-catenin signaling remained activated in chronic HCV-infected cells after HCV eradication by DAA, but metformin reversed it through PKA/GSK-3 beta-mediated beta-catenin degradation, inhibited colony-forming ability and proliferation, and increased apoptosis, suggesting that DAA therapy in combination with metformin may be a novel therapy to treat HCV-associated HCC where metformin suppresses Wnt/beta-catenin signaling for HCV-infected patients.