Identification of β-1,4-galactosyltransferase I as a target gene of HBx-induced cell cycle progression of hepatoma cell

Background/Aims The hepatitis B virus-encoded HBx protein contributes to hepatocarcinogenesis with largely unknown mechanisms. It is widely known that N-linked oligosaccharides on glycoproteins are structurally altered during malignant transformation and these alterations are often associated with malignant transformation of cells. β-1,4-galactosyltransferase I (GalT I) contributes to the biosynthesis of Galβ → 4GlcNAc structure in the outer chain moieties of N-glycans. Methods The difference of GalT I expression between normal liver and hepatoma tissues were investigated; the effect of HBx on GalT I expression was investigated; the role of GalT I in hepatoma cell growth and HBx-induced hepatoma cell growth were investigated. Results GalT I was highly expressed in hepatocellular carcinoma and transcriptionally up-regulated by HBx, and functioned as a positive growth regulator in hepatoma cells. Furthermore, decreasing the expression of GalT I in hepatoma cells reduced the ability of tumor formation in vivo and inhibited HBx-induced cell cycle progression. Conclusions HBx-induced GalT I expression might contribute to HBx-mediated HCC development and progression.