Involvement of NF-κB Pathway in Multidrug Resistance Induced by HBx in Hepatoma Cell Line

Aim: To investigate the molecular mechanism of the influence of HBx protein on multidrug resistance in hepatoma cells and the potential role of NF-κB pathway in this process.Methods:HBx-expressing cell was established by liposome-mediated transfection of HBx gene into HepG2 cell line. And MTT assay was used for cell viability analysis. AnnexinV-FITC/PI assay was used for the analysis of apoptosis. The expression of MDR-associated genes and proteins were detected by Real time-PCR and Western blot. The NF-κB pathway activation was measured by confocal through immunofluorescence staining of p65. And SQ-Real time-PCR was also applied to analyze the alterations in the expression of Gadd45βand Survivin after treated with the NF-κB pathway inhibitor IMD-0354.Results:We found that HBx expression in HCC cell lines induces drug resistance against multi-drugs. Compared with the control group, the HBx transfected cells showed a higher expression of MDR associated genes and anti-apoptotic gene. And we found a significantly lower apoptosis ratio in HepG2-HBx and HepG2.2.15 cells, compared with HepG2, HepG2-3.1 cells (P<0.05) after treating with 5-FU or ADM. Furthermore, we found that the NF-κB activity was remarkably high in the HBx-expressing cells as measured by p65 nuclear localization. In addition, the upregulated anti-apoptotic gene, Gadd45βand Survivin, in HBx-expressing HCC cell lines was downregulated by IMD-0354 treatment. Conclusions:HBx protein might be one of the causes for the occurrence of MDR in HCC, and NF-κB pathway might be involved in this change.