[Hepatocyte transformation and tumor development induced by hepatitis C virus NS3 N-terminal protein].
OBJECTIVE
To study the effect of hepatitis C virus nonstructural protein 3 N-terminal protein (HCV NS3-5') on hepatocyte transformation and tumor development.


METHODS
QSG7701 cells were transfected with plasmid pRcHCNS3-5' (expressing HCV NS3 N-terminal protein) by lipofectamine and selected in G418. The expression of HCV NS3 gene and protein was determined by PCR and immunohistochemistry respectively. Biological effect of transfected cells was observed through cell proliferation assay, anchor independent growth, and tumor development in nude mice. The expression of HCV NS3 and c-myc protein in the induced tumor was evaluated by immunohistochemistry.


RESULTS
HCV NS3 was strongly expressed in QSG7701 cells transfected with plasmid pRcHCNS3-5' and the positive signal was located in cytoplasm. The HCV NS3 expression and c-myc protein in the induced cytoplasm. Cell proliferation assay showed that the population doubling time in the pRcHCNS3-5' transfected cells was much shorter than that in the pRcCMV and non-transfected cells (24 h, 26 h, 28 h respectively). The cloning efficiencies of transfected cells with pRcHCNS3-5', pRcCMV and non-transfected cells were 33.0%, 1.5%, 1.1% respectively (P < 0.01). Tumor developed in nude mice inoculated with pRcHCNS3-5'transfected cells 15 days after the inoculation. HE staining showed hepatocarcinoma character and immunohistochemistry confirmed HCV NS3 and c-myc expression in the tumor tissue. The positive control group also showed tumor development, while no tumor mass obtained in the nude mice inoculated with pRcCMV and non-transfected cells even 40 days after the injection.


CONCLUSIONS
HCV NS3 N-terminal protein showed cell transformation and tumorigenic features.
He
Qiong-qion
QQ
Department of Pathology, Xiangya School of Medicine, Central South University, Changsha 410078, China.
Cheng
Rui-xue
RX
Sun
Yi
Y
Feng
De-yun
DY
Zheng
Hui
H
D000818:Animals; D002455:Cell Division; D002471:Cell Transformation, Neoplastic; D005260:Female; D022781:Hepatocytes / Q000473:pathology*; D006801:Humans; D008114:Liver Neoplasms, Experimental / Q000209:etiology*; D051379:Mice; D008819:Mice, Nude; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation; D014162:Transfection; D017361:Viral Nonstructural Proteins / Q000633:toxicity*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D020928:Mitogen-Activated Protein Kinases; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases