Abstract: Objective This study aimed to explore the mechanism of miR-556-3p in the development of hepatocellular carcinogenesis. Methods The miR-556-3p level in cancerous and its adjacent non-cancerous tissues from patients with hepatocellular carcinoma was detected by real-time fluorescence quantitative PCR, and the phosphatase and tensin homolog (PTEN) expression was revealed by immunohistochemistry. The expression patterns of PTEN/ protein kinase B(Akt) signaling pathway-related proteins were detected by Western blotting after transfection of HepG2 cells with miR-556-3p mimic, miR-556-3p NC, PTEN cDNA and PTEN siRNA. The proliferation ability of HepG2 cells was studied by CCK-8 method, the invasion ability of cells was determined by Transwell method, and the apoptosis was detected by flow cytometry. The regulatory roles of miR-556-3p on PTEN/AKT pathway in HepG2 cells were evaluated by bioinformatics. Results The miR-556-3p loads in cancerous tissues was significantly lower than that in para-neoplastic tissues (P<0.05), and the miR-556-3p loads in HepG2 cells was also significantly lower than that in LO2 cells (P<0.05); the luciferase analysis showed that PTEN was a direct target of miR-556-3p; the proliferation rate, invasion rate and apoptosis rate in miR-556-3p-transfected HepG2 cells decreased significantly than in miR NC-transfected cells (P<0.05); the PTEN overexpression reversed the growth inhibition and apoptosis induction of miR-556-3p in HepG2 cells; the miR-556-3p inhibited PTEN/AKT activation by targeting PTEN. Conclusions The miR-556-3p loads decrease in hepatocellular carcinoma tissues, and the miR-556-3p inhibits the proliferation and invasion, and induce apoptosis in HepG2 cells. The PTEN is regulated by miR-556-3p in HepG2 cells. These findings above suggest that miR-556-3p is closely related to the transformation of liver cells, which needs further verification.

Key words: Hepatoma, HepG2 cells, miR-556-3p, Phosphatase and tensin homolog/ protein kinase B, Proliferation, Apoptosis, Metastasis, In vitro