Abstract: OBJECTIVE: To observe the transformation in normal hepatic cell line L02 by the hepatitis B virus X (HBX) protein and the effect of HBX protein on the activity of telomerase. METHODS：PEGFP-N1-HBX plasmids were constructed and transfected into L02 normal liver cells，the expression of EGFP was assessed by fluorescence microscope. The expression of HBX protein in L02 cells was measured by Western blotting analysis. Cellular morphology was studied by electron microscope. The proliferation of L02 cells after stably transfected with plasmids was measured by MTT assay. The expressions of hTERT mRNA was detected by RT-PCR in L02 cells after stably transfected with plasmids. The activity of telomerase was evaluated by TRAP-PCR argentation in L02 cells after stably transfected with plasmids. RESULTS：PEGFP-N1-HBX plasmid was successfully constructed. The expression of HBX protein was observed in normal liver L02 cells. The cell morphology after transfection with PEGFP-N1-HBX plasmid appeared immature and with the trend of malignant transformation. Compared with the L02 cells after transfection with PEGFP-N1 plasmid，PEGFP-N1-HBX transfection promoted the proliferation of L02 cells (P<0.05).The hTERT mRNA expression increased in L02 cells after transfection with PEGFP-N1-HBX plasmid and telomerase was activated. CONCLUSION： HBX protein could induce normal liver L02 cells torword malignant transformation，enhance the expression of hTERT mRNA and activate telomerase.

Key words: hepatitis B virus X protein, hepatocellular carcinoma, telomerase, gene therapy