The Effect And Mechanism Of Hepatitis B Virus X Protein On The Proliferation In HL7702Cells

【Objective】:1. To investigate the effects of HBx on the cell proliferation and the expression ofCOX-2in HL7702cells.2. To analyze the effect of50μmol/L NS-398，a COX-2selective inhibitors, on HBxstably transfected HL7702cells to observe whether HBx enhances proliferation ofliver cells via COX-2．【Methods】:HL7702/HBx，HL7702/Mock and HL7702cell were used. The effects of HBx onliver cell proliferation were examined using cell-counting kit-8(CCK-8) assay andclone formation assay. To test whether expression of HBx influences COX-2, wedetected COX-2mRNA expression by RT-PCR and protein expression by westernbolt. The cell proliferation were measured by CCK-8after treated cells with theselective COX-2inhibitor NS-398(50μmol/L) and DMSO as controls for24h,48h,72h respectively. After treated with selective COX-2inhibitor NS-398(50μmol/L) and DMSO as controls for72h, the expression of COX-2protein wasdected in all cells.【Results】:Cell viability assay and plate colony formation assay displayed that, comparedwith HL7702/Mock and HL7702cells, HL7702/HBx cells increased proliferationrate and formed more colonie（sP<0.05）. COX-2mRNA and protein expressionswere increased in HL7702/HBx cells compared with HL7702/Mock andHL7702cells （P<0.05）. NS-398suppressed the growth of all cells in atime-dependent manner.The growth inhibition rate of HL7702/HBx cells were significantly higher in the three time points respectively（P<0.05）,when comparedwith HL7702/Mock and HL7702. After treatment with50μmol/L selective COX-2inhibitor NS-398for72h,all cells showed decreasing level of COX-2expression,and this is obvious in HL7702/HBx cells（P<0.05）.【Conclusions】:1. HBx can enhance the cell proliferation of HL7702liver cells，while increasedCOX-2mRNA and protein expressions.HBx may promote the proliferation ofHL7702liver cells via upregulating COX-2, which may be involved in the earlystage of hepatocarcinogenesis.2. COX-2selective inhibitor NS-398treatments significantly suppressed the cellularproliferation in all cells in COX-2dependent manner,and HL7702/HBxcells,which overexpressed COX-2protein,was more susceptible to NS-398induced growth inhibition.