TGF-β promotes proliferation and inhibits apoptosis of liver cancer Huh-7 cells by regulating MiR-182/CADM1

Purpose: To investigate the mechanism of liver cancer cell tolerance to the antiproliferative effect of transforming growth factor beta (TGF-β) based on miRNA levels.Methods: MiRNA microarray and quantitative reverse transcription-polymerase chain reaction (qRTPCR) were used to identify differentially expressed miRNAs in liver cancer Huh-7 cells treated with TGF-β. The effect of these miRNAs on patient survival was analyzed using Kaplan-Meier Plotter. Involvement of Smad2/Smad3 in TGF-β-induced miR-182 expression was determined using shRNA knockdown and qRT-PCR. Dose-dependent effect of TGF-β on miR-182 expression was investigated in Huh-7 cells and mouse primary liver cells using qRT-PCR. The effect of miR-182 on Huh-7 cell proliferation and apoptosis was studied using CFSE and Annexin V/PI assay. Direct targets of miR-182 in Huh-7 cells were identified using a luciferase reporter gene assay, while the influence of Recombinant Cell Adhesion Molecule 1 (CADM1) overexpression on Huh-7 cell proliferation and apoptosis treated with miR-182 was examined using lentivirus experiments, and CFSE and Annexin V/PI assays.Results: The expression levels of hsa-miR-181a, hsa-miR-182, hsa-miR-483, and hsa-miR-143 were significantly higher in serum samples from liver cancer patients (p < 0.05). Survival analysis showed that low expression of hsa-miR-182 and high expression of hsa-miR-483 increased the survival rate of liver cancer patients. Furthermore, TGF-β increased miR-182 expression in Huh-7 cells, but not in mouse primary liver cancer cells. The MiR-182 promoted Huh-7 cell proliferation and inhibited apoptosis. It targeted CADM1 mRNA 3'-UTR, decreasing CADM1 expression. Overexpression of MiR-182 significantly reduced cell proliferation and increased apoptosis in Huh-7 cells with CADM1 overexpression (p < 0.05).Conclusion: Transforming growth factor beta (TGF-β) facilitates the proliferation and repression of apoptosis of Huh-7 cells by increasing miR-182 expression and inhibiting CADMI expression.