Serum-and-glucocorticoid-inducible-kinase-2 is overexpressed and mediates glycogen synthase kinase-3β/ β-catenin signal transduction in hepatocellular carcinoma

Abstract

Objective: To investigate the differential expression of serum-and-glucocorticoid-inducible-kinase-2 (SGK2) in hepatocellular carcinoma (HCC) and normal liver tissues and the related mechanism mediating signal transduction of GSK-3 β / β catenin in HCC cells. Methods: Twenty pairs of matched HCC and normal tissues were collected and the situation of expression of SGK2 mRNA was detected by real-time fluorescence quantitative PCR. Western blot was used to detect the levels of SGK2 protein in human HCC cell lines (Huh-7, SMMC-7721) and normal human liver cell line (L02). SGK2 siRNA was used to transfect human HCC cell lines (SMMC-7721 and Huh-7), and then the protein expression levels of GSK-3 β/ β - catenin was successfully detected with the above-mentioned transfected cell line by western blot. Measurement data were expressed as mean ± standard deviation (x±s), and the Student t -test was used as the statistical method. Results: SGK2 mRNA expression was up-regulated in all 20 HCC samples than that of the expression of matched normal liver tissues. SGK2 protein levels were significantly higher in Huh-7 and SMMC-7721 than normal human liver cell lines (P < 0.01). The downregulation of SGK2 expression in human HCC cell lines (SMMC-7721 and Huh-7) had inhibited the expression of unphosphorylated GSK-3 β. In addition, the downregulation of SGK2 expression in HCC cell lines had decreased the dephosphorylation of β - catenin to prevent degradation of the β - catenin proteasome. Conclusion: SGK2 is overexpressed in HCC and mediates GSK-3β/β- catenin signaling in HCC cells.