Effect of HBX protein on the multidrug resistance of hepatocellular carcinoma

Objective To explore the effects of HBX protein on the formation of multidrug resist- ance of hepatocenular carcinoma (HCC) and identify the relationship between MDR of HCC and HBV in- fectiun.Methods Liposome carrying pcDNA3/HBX plasmid was transfected into HepG2 cells.MTT method was used to determine the viability of the transfected and non-transfected HepG2 cells exposed to ADM or MMC.Apoptosis index (AI) of the transfected HepG2 cells was analyzed by Annexin/PI method using flow eytometry after administration of 5-Fu.The expression of a cohort of the MDR related genes at mRNA and protein levels was detected by RT-PCR and Western blot respectively.Results MTT assay re- vealed that IC50 of the transfected HepG2 cells exposed to ADM or MMC was significantly higher than that in the control group (P0.05 ).AI in the transfection group and control group was (9.83±1.5)% and (17.79±1.7)% respectively after administration of 5-Fu (P0.05).The expression of a cohort of the MDR related gene in HepG2 cells transfected with pcDNA3/HBX plasmid was higher than non-transfected cells,that was,at mRNA level,the copies of mdr1,MRP1,LRP gene in transfected cells were respectively higher 190%,68%,95% than those in non-transfected cells;at protein level,the amounts of p-gp, MRP1,LRP protein in the transfection group were respectively higher 64.3%,87.5% and 90.8% than those in control group.Conclusion HBX protein could up-regulate the expression of a cohort of the MDR related genes in HepG2 ceils and facilitate the development of MDR of HCC.