Metformin synergistically enhances the antitumour activity of Lenvatinib in hepatocellular carcinoma by altering AKT‐FOXO3 signalling pathway

Abstract Background and Aims Lenvatinib is a first‐line drug commonly used in the treatment of advanced hepatocellular carcinoma (HCC). However, its clinical efficacy is very limited due to drug resistance. Therefore, there is a great need to explore its combination with other agents to achieve better therapeutic effects. Metformin has been demonstrated to show an anti‐cancer effect. This study aimed to investigate the combined effect of lenvatinib with metformin in HCC cells both in vitro and in vivo and elucidate the possible molecular mechanisms. Methods Flow cytometry, colony formation, CCK‐8 and transwell assays were used to study the effect of Lenvatinib–Metformin combination on the malignant behaviour of HCC cells in vitro. Constructing an animal model of tumour‐bearing to study the effect of combined drugs on HCC in vivo. Western blot experiments were performed to assess the relationship between AKT and FOXO3 and the cellular translocation of FOXO3. Results Our results suggested that Lenvatinib and Metformin synergistically inhibited HCC growth and motility. Mechanistically, the combination of Lenvatinib and Metformin synergistically suppressed the activation of the AKT signalling pathway, which in turn reduced the phosphorylation level of downstream effector FOXO3 and induced its nuclear aggregation. In vivo studies further confirmed the synergistic suppression of lenvatinib with metformin in HCC growth. Conclusion The Lenvatinib–Metformin combination may provide a potential therapeutic strategy to improve the prognosis of HCC patients.