Effect Of HBV X Gene Transfection On Apoptosis Of QBC939 And Its Mechanism

we transfected eukaryotic expression vector containing entire HBx gene coding region, pcDNA3-x, into human CC cell QBC939 using Lipofectamine. Successful transfection was confirmed by RT-PCR and Western blot. The results of DAPI and cytometry flow showed that transfection of pcDNA3-x into QBC939 cells induced apoptosis. We then investigated the precise mechanisms of this apoptotic process. Our results showed that overexpression of HBx in QBC939 cells induced increase of ratio between Bax and Bcl-XL, loss of mitochondrial transmembrane potential (Δψm) and release of cytochrome c from mitochondria into cytosol, indicating that mitochondrial apoptotic pathway is involved in HBx-induced cell death in QBC939 cells. As a important regulator of apoptosis, NF-κB play pro-apoptotic or anti-apoptotic role according to diverse stimuli. In our study, p65, a important subunit of NF-κB, accumulated in nuclei, and reporter gene assay showed that transcriptional activity of NF-κB increase after overexpression of HBx in QBC939 cells. As target genes of NF-κB, Fas and c-myc, which are pro-apoptotic genes, were upregulated at mRNA level, indicating that NF-κB plays a pro-apoptotic role in HBx-induced cell death in QBC939 cells. Taken together, our study gives a new view angle to the research of correlation of HBV infection and cholangiocarcinogenesis.