Sensitivity of HepG2 cells with stably expressing HBx via rosiglitazone and its mechanism / 肿瘤

ABSTRACT

Objective: To establish a HepG2 cell line with stable expression of x protein of hepatitis B virus (HBx), detect its sensitivity to rosiglitazone, and explore the mechanism for the role of the interaction of HBx with peroxisome proliferato-activated receptor γ(PPARγ) in hepatocarcinogenesis. Methods: This work constructed pIRES2-HBx eukaryotic expression plasmid, screened HepG2 cell clone with stable expression of HBx. The sensitivity of HBx-expressing HepG2 cells to rosiglitazone was assessed by MTT assay. The change in PPARγ location was detected by immunocytochemistry. The mRNA and protein expressions of PPARγ were determined by RT-PCR and Western blotting respectively. Results: This work successfully constructed pIRES2-HBx eukaryotic expression plasmid and obtained the HepG2 cell line with stable expression of HBx. The inhibitory effect of rosiglitazone on HBx-expressing HepG2 cells decreased obviously, but the inhibitory effect was partly reversed when the cells were pretreated with PD98059, an inhibitor of mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1 (MEK1). The difference in PPARγ expression was not significant. But the location of PPARγ was changed. It moved from nucleus to cytoplasm. Conclusion: HBx reduces the sensitivity of HepG2 cells to rosiglitazone. The possible mechanism is that HBx changes the site-specific location of PPARγ and decreases its binding ability to DNA, thus influence the binding of PPARγ to its ligand and the activity of PPARγ through phosphorylation pathway.