Hepatitis C virus core protein induces malignant transformation of biliary epithelial cells by activating nuclear factor-kappaB pathway.
In an earlier study, we found that hepatitis C virus core protein, HCV-C, participated in the malignant transformation of HCV-C transfected normal human biliary epithelial (hBE) cells by activating telomerase. Here we further investigated the signaling of the malignant transformation.


METHODS
Reverse transcription-polymerase chain reaction (RT-PCR), western blotting and immunoprecipitation were used to analyze the expression of HCV-C, human telomerase reverse transcriptase (hTERT), nuclear factor-kappaB (NF-kappaB) and NF-kappaB inhibitor alpha (IkappaBalpha) genes and the phosphorylation level of IkappaBalpha protein. Electrophoretic mobility shift assays (EMSA) and NF-kappaB-linked luciferase reporter assays were carried out to measure NF-kappaB activity.


RESULTS
The expression of HCV-C and hTERT was detected only in HCV-C-transfected hBE (hBE-HCV-C) cells but not in vector-transfected or parental hBE cells. More NF-kappaB protein accumulated in nuclear extracts of hBE-HCV-C cells rather than in those of control cells, though total NF-kappaB protein level showed no difference among these cells. DNA binding activity of NF-kappaB and the NF-kappaB-linked luciferase activity were much higher in HCV-C-transfected hBE cells than those in vector- or non-transfected hBE cells. In addition, the IkappaBalpha phosphorylation level, but not the IkappaBalpha mRNA or protein levels, was increased after HCV-C transfection.


CONCLUSIONS
Hepatitis C virus core protein activates NF-kappaB pathway in hBE cells by increasing the phosphorylation of IkappaBalpha. The pathway may be responsible for HCV-C-induced malignant transformation of hBE cells.
Li
Zhi-Hua
ZH
Department of Oncology, Affiliated Second Hospital, Sun Yat-sen University, Guangzhou, China.
Tang
Qi-Bin
QB
Wang
Jie
J
Zhou
Ling
L
Huang
Wen-Lin
WL
Liu
Ran-Yi
RY
Chen
Ru-Fu
RF
D001659:Biliary Tract / Q000378:metabolism*; D001665:Binding Sites; D015153:Blotting, Western; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism*; D002472:Cell Transformation, Viral / Q000235:genetics; D004247:DNA / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004847:Epithelial Cells / Q000378:metabolism*; D017930:Genes, Reporter; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D047468:Immunoprecipitation; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D019098:Telomerase / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection; D014758:Viral Core Proteins / Q000235:genetics / Q000378:metabolism*
D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D014758:Viral Core Proteins; C069130:nucleocapsid protein, Hepatitis C virus; D000072000:NF-KappaB Inhibitor alpha; D004247:DNA; C509186:TERT protein, human; D019098:Telomerase