Metformin Inhibits The Prometastatic Effect Of Low-dose Sorafenib In HCC By Upregulating The Expression Of TIP30

ObjectiveAlthough the low dose of sorafenib can inhibit the growth of hepatocellular carcinoma, it can promote the ability of metastasis. Here we want to determine whether metformin could enhance the efficacy and reverse the pro-metastatic effect of the low dose of sorafenib treatment in hepatocellular carcinoma, and explore the potential molecular mechanism.ContentTo investigate the efficacy of the combination of metformin and the low-dose sorafenib on the orthotopic MHCC97 H models, the tumor size, lung metastasis and the survival of nude mice were observed. In vitro experiments, certain concentration of metformin, sorafenib and the combined therapy were applied to the MHCC97 H cell line to detect the changes of the related protein expression and the ability of proliferation and invasiveness.Methods1) Subcutaneous tumor model was established in BALB?c nude mouse by injecting the MHCC97 H cells. Four weeks later, the tumor was removed aseptically and dissected into 1mm3 blocks, then implanted into the mouse liver orthotopically. Metformin(200 mg/kg/day), sorafenib(30 mg/kg/day) and a combination of both two drugs were given daily orally one week later after in situ implantation. Another four weeks later, the orthotopic tumor size and the number of lung metastasis were observed. Another four groups of mice were used to evaluate the overall survival.2) In vitro experiments, the MHCC97 H cells were treated with metformin(5 m M or 10 m M), sorafenib(5?M) or the combination of them. Western blotting, Transwell and CCK-8 were used to observe the expression level of TIP30, p-AMPK and TXN protein, the change of cell proliferation and invasion ability.Results1) In vivo experiments, the data showed that the combination of sorafenib and metformin could prolong the median survival and reduce tumor volume and lung metastasis in orthotopic MHCC97 H models.2) In vitro experiments, metformin upregulated the expression of TIP30 protein in MHCC97 H cell line by activating AMPK pathway, while the combination of sorafenib and metformin reversed the downregulated expression of TIP30 by sorafenib alone. The expression of TXN which plays an important role in tumor metastasis process was reduced by the combined treatment, and this effect was negatively regulated by TIP30. When treated with sorafenib and metformin, the ability of proliferation and invasion of MHCC97 H cells were significantly suppressed.ConclusionsMetformin could enhance the efficacy and reverse the pro-metastatic of the low dose of sorafenib treatment in hepatocellular carcinoma. Activation of AMPK pathway to upregulate the expression of TIP30, which negatively regulates the expression of TXN is mainly responsible for this synergistic anti-HCC effect.