ABSTRACT
@#Abstract: Objective To construct HepG2, Huh7 cell lines stably express hepatitis B virus X (HBx) mutant (C1653T, T1753C), and explore their effect on the biological behavior of hepatocellular carcinoma cells. Methods The lentivirus plasmid of pLVX-HBxC1653T-IRES-tdTomato, pLVX-HBxT1753C-IRES-tdTomato were obtained by PCR site mutagenesis according to wild type ayr HBx. Double enzyme digestion and Sanger sequencing were performed for accuracy of plasmid. Blank HepG2 and Huh7 cells were used as the control group, HepG2, Huh7 cells were infected by pLVX-HBx-IRES-tdTomato, pLVX-HBxC1653T-IRES-tdTomato, and pLVX-HBxT1753C-IRES-tdTomato lentivirus solution, then monoclonal cell was selected by 0.6 μg/mL puromycin. Immunostaining and Western Blot were performed for the verification of stable strains. CCK8 assay was performed for the proliferation capacity of stable strains. Western Blot was performed for expression of EMT-related signal molecules in cells. The independent samples t-test was used for comparison between two groups. Results Double enzyme digestion and Sanger sequencing showed that that the size of the cut fragments of recombinant lentiviral plasmids was correct, and the point mutation location and base substitution were correct, suggesting that the plasmid of pLVX-HBx-IRES-tdTomato, pLVX-HBxC1653T-IRES-tdTomato, pLVX-HBxT1753C-IRES-tdTomato were constructed successfully. Immunostaining and Western blot showed that HBX were expressed in stable strains, while there was no HBX expression in the blank control group, indicating that the HepG2 and Huh7 cell lines stably expressing HBx, HBxC1653T, HBxT1753C were successfully constructed. CCK8 assay showed that the proliferation capacity of HBx and mutant were enhanced compared to the control group (P<0.01), HBx C1653T displayed further additive the effect compared to HBx (P<0.05). Moreover, HBxC1653T mutation also significantly upregulated N-cadherin expression and downregulated E-cadherin expression, thus promoting the occurrence of EMT. Conclusions HepG2 and Huh7 cell lines stably expressing HBx, HBxC1653T, HBxT1753C were successfully constructed, HBxC1653T mutation significantly enhanced the proliferation of HCC cells and epithelial to mesenchymal transition occurrence.