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


METHODS
QSG7701 cells were transfected with plasmid pRcHCNS3-5' (expressing HCV NS3 c-terminal deleted protein) by lipofectamine and selected in G418. The expression of HCV NS3 gene and protein was determined by PCR and immunohistochemistry respectively. Biological behavior of transfected cells was observed through cell proliferation assay, anchorage-independent growth and tumor development in nude mice. The expression of HCV NS3 and c-myc proteins 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. Cell proliferation assay showed that the population doubling time in pRcHCNS3-5' transfected cells was much shorter than that in pRcCMV and non-transfected cells (24 h, 26 h, 28 h respectively). The cloning ratio of cells transfected with pRcHCNS3-5', pRcCMV and non-transfected cells was 33 %, 1.46 %, 1.11 %, respectively, the former one was higher than that in the rest two groups (P<0.01). Tumor development was seen in nude mice inoculated with pRcHCNS3-5' transfected cells after 15 days. HE staining showed its feature of hepatocarcinoma, and immunohistochemistry confirmed the expressions of HCV NS3 and c-myc proteins in tumor tissue. The positive control group inoculated with HepG2 also showed tumor development, while no tumor developed in the nude mice injected with pRcCMV and non-transfected cells after 40 days.


CONCLUSIONS
1.HCV NS3 c-terminal deleted protein has transforming and oncogenic potential. 2. Human liver cell line QSG7701 may be used as a good model to study HCV NS3 pathogenesis.
He
Qiong-Qiong
QQ
Department of Pathology, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan Province, China.
Cheng
Rui-Xue
RX
Sun
Yi
Y
Feng
De-Yun
DY
Chen
Zhu-Chu
ZC
Zheng
Hui
H
D000818:Animals; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D017353:Gene Deletion; D022781:Hepatocytes / Q000502:physiology*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000209:etiology*; D010446:Peptide Fragments / Q000235:genetics / Q000502:physiology; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000502:physiology*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D010446:Peptide Fragments; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases