To evaluate the effect of hepatitis B virus X protein (HBx) on the proliferation and migration of HBV-associated hepatocellular carcinoma (HCC) and the mechanism.

The HCC cell lines (SMMC7721 and Huh7) stably overexpressing HBx were constructed. The effect of HBx upon the proliferation and migration of HCC cells was assessed by CCK-8 assay, plate cloning experiment and Transwell chamber test. The differentially-expressed microRNAs (miRNAs, miR) inHBV-associated HCC were identified by miRNA chip data. The expression levels of lncRNA PTENpg1 and miR-21 were measured by fluorescent quantitative PCR. The expression level of PTEN was detected by Western blot. The HCC cell lines (SMMC7721 and Huh7) overexpressing miR-21 were constructed. The effect of miR-21 on the proliferation and migration of HCC cells was evaluated by CCK-8 assay, plate cloning experiment and Transwell chamber test.

Plate cloning experiment, CCK-8 assay and Transwell chamber test showed that overexpression of HBx promoted the colony formation, proliferation and migration of HCC cells. Analysis of siRNA chip data demonstrated that miR-21 was a differentially-expressed gene of HBV-associated HCC. Fluorescent quantitative PCR revealed that the expression level of lncRNA PTENpg1 was significantly down-regulated, whereas that of miR-21 was significantly up-regulated after HBx overexpression. Western blot showed that the expression level of PTEN protein was down-regulated while the HBx and miR-21 were over expressed. Plate cloning experiment, CCK-8 assay and Transwell chamber test indicated that up-regulation of miR-21 promoted the proliferation and migration of HCC cells.

HBx can promote the incidence and progression of HBV-associated HCC by regulating the lncRNA PTENpg1-miR-21-PTEN molecular signaling pathway.