Metformin sensitizes sorafenib to inhibit postoperative recurrence and metastasis of hepatocellular carcinoma in orthotopic mouse models

Combination of metformin and sorafenib suppresses proliferation and induces autophagy of hepatocellular carcinoma via targeting the mTOR pathway

The multi‑kinase inhibitor sorafenib is the only drug for which randomized control trials have shown improved patient survival in advanced hepatocellular carcinoma (HCC). However, life expectancy is extended in these cases by only a few months. The anti‑type II diabetes agent metformin was used in this study in an effort to find a more efficient approach to HCC treatment. Sorafenib effectively reversed the activation status of mTORC2 induced by metformin and enhanced the suppression of the mTORC1 and MAPK pathway by metformin in HCC cells, which may be responsible for reduced proliferation upon combined treatment. The metformin and sorafenib combination led to increased impaired proliferation and tumor inhibition of HCC in vitro and in vivo compared to single agent, which was partially bridged by disrupting the mTORC1/mTORC2 feedback loop. Metformin and sorafenib cooperated to promote apoptosis and autophagy in HCC cells. Pharmacological inhibition of autophagy sensitized HCC cells to metformin and sorefenib‑induced apoptotic cell death. Therefore, the anti‑autophagy treatment should be considered in metformin and sorafenib-based treatments in HCC cells.

TMED3 promotes hepatocellular carcinoma progression via IL-11/STAT3 signaling

Transmembrane p24 trafficking protein 3(TMED3) is a metastatic suppressor in colon cancer, but its function in the progression of hepatocellular carcinoma (HCC) is unknown. Here, we report that TMED3 was up-regulated in HCC and portal vein tumor thrombus. TMED3 up-regulation in HCC was significantly correlated with aggressive characteristics and predicted poor prognosis in HCC patients. TMED3 overexpression in HCC cell lines promoted cell migration and invasion. In contrast, TMED3 knockdown suppressed HCC metastasis both in vitro and in vivo. Gene microarray analysis revealed decreased IL-11 expression in TMED3-knockdown cells. We propose that TMED3 promotes HCC metastasis through IL-11/STAT3 signaling. Taken together, these findings demonstrate that TMED3 promotes HCC metastasis and is a potential prognostic biomarker in HCC.

Metformin Inhibits TGF-β1-Induced Epithelial-to-Mesenchymal Transition via PKM2 Relative-mTOR/p70s6k Signaling Pathway in Cervical Carcinoma Cells

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) plays a prominent role in tumorigenesis. Metformin exerts antitumorigenic effects in various cancers. This study investigated the mechanisms of metformin in TGF-β1-induced Epithelial-to-mesenchymal transition (EMT) in cervical carcinoma cells.

METHODS

cells were cultured with 10 ng/mL TGF-β1 to induce EMT and treated with or without metformin. Cell viability was evaluated by CCK-8 (Cell Counting Kit 8, CCK-8) assay; apoptosis were analyzed by flow cytometry; cell migration was evaluated by wound-healing assay. Western blotting was performed to detect E-cadherin, vimentin, signal transducer and activator of transcription 3 (STAT3), snail family transcriptional repressor 2 (SNAIL2), phosphorylation of p70s6k (p-p70s6k) and -Pyruvate kinase M2 (PKM2) Results: TGF-β1 promoted proliferation and migration, and it attenuated apoptosis compared with cells treated with metformin with or without TGF-β1 in cervical carcinoma cells. Moreover, metformin partially abolished TGF-β1-induced EMT cell proliferation and reversed TGF-β1-induced EMT. In addition, the anti-EMT effects of metformin could be partially in accord with rapamycin, a specific mTOR inhibitor. Metformin decreased the p-p70s6k expression and the blockade of mTOR/p70s6k signaling decreased PKM2 expression.

CONCLUSION

Metformin abolishes TGF-β1-induced EMT in cervical carcinoma cells by inhibiting mTOR/p70s6k signaling to down-regulate PKM2 expression. Our study provides a novel mechanistic insight into the anti-tumor effects of metformin.