Metformin reverses bFGF-induced epithelial-mesenchymal transition in HCC cells

Metformin had exerted important inhibitory effects in multiple cancers. However, the correlation between metformin and hepatocellular carcinoma (HCC) metastasis, and the relevant mechanisms are still unclear. By quantitative proteomics analysis technique, we found metformin could suppress FGF signalling significantly. In FGF signalling basic fibroblast growth factor (bFGF) is a crucial member, it initially binds to its receptors, the complex of bFGF and receptors activate FGF signallings, and promote many cancers progressions. When treating HCC cell lines HepG2 and Huh7 with bFGF, we observed the cells exhibited epithelial mesenchymal transition (EMT) and these cells metastasis potential was enhanced dramaticlly. However, when treating with metformin and bFGF together, EMT and metastasis induced by bFGF could be inhibited in these cells. Furthermore, bFGF could activate AKT/GSK-3β signalling, sequentially decrease the interaction between GSK-3β and Twist1 and decrease ubiquitination of Twist1 leading to Twist1 degradation reducing. While metformin could repress the bFGF-mediated activation in AKT/GSK-3β signalling, inhibition on interaction between GSK-3β and Twist1, enhancement of Twist1 stability. Taken together, our findings suggested that metformin had prominent negative effects on bFGF-induced EMT and metastasis in HCC cells.