[The effects of hepatitis C virus core protein on biological behaviors of human hepatocytes].
OBJECTIVE
To investigate the effects of hepatitis C virus (HCV) core protein on the biological behaviors of human hepatocytes and their underlying mechanism.


METHODS
A cell line expressing stably HCV core protein-QSG7701/core was constructed by transfecting the plasmid pcDNA3.1-core (expressing HCV core protein) into the human immortalized hepatocytes of the line QSG7701. The biological behaviors of these transfected cells were observed through plating-efficiency test, growth curve and flow cytometry (FCM). The association between HCV core protein and the expression of activated caspase-3 protein was evaluated by immunocytochemistry. The phosphorylation of mitogen-activate protein kinases (MAPKs) was detected with Western blotting. The activation of nuclear transcriptors AP-1, important effector molecule of MAPKs, and nuclear factor-kappa binding (NF-kappaB) were evaluated with luciferase assays and electrophoretic mobility shift assay (EMSA).


RESULTS
HCV core protein was expressed in the QSG7701/core cells and not in the QSG7701/pcDNA3.1 cells and untransfected QSG7701 cells. There were no significant differences in the expression levels of total P44/42(MAPK), p38(MAPK) and JNK among the QSG7701/core cells, QSG7701/pcDNA3.1 cells and untransfected QSG7701 cells. The expression levels of phophorylated P44/42(MAPK), p38(MAPK) and JNK in the QSG7701/core cells were significantly weaker than those in the QSG7701/pcDNA3.1 cells and untransfected QSG7701 cells. Plating efficiency test showed that the clone formation rate of the QSG7701/core cells was 32.25%, significantly lower than those of QSG7701/pcDNA3.1 and untransfected QSG7701 cells (47.5% and 42.5% respectively, both P < 0.01). The growth curve showed that the multiplication time of the QSG7701/core cells was 36 hours, significantly longer than those of the QSG7701/pcDNA3.1 and untransfected QSG7701 cells (27 and 28 hours respectively). FCM showed that the apoptotic rate of the QSG770/1core was 1.04%, lower than those of the QSG7701/pcDNA3.1 and untransfected QSG7701 cells (1.68% and 3.7% respectively), and that the percentage of theQSG770/1core cells at the G(0)/G(1) stage increased and those in the S stage decreased. Immunocytochemistry showed that the expression intensity of caspase-3 in the QSG7701/core cells was significantly weaker than those of the QSG7701/pcDNA3.1 cells and untransfected QSG7701 cells.


CONCLUSIONS
HCV core protein suppresses cell proliferation and apoptosis by downregmicrolating the phosphorylation of MAPKs and activating the transcriptors AP-1 and NF-kappaB, thus promoting the persistency of HCV infection which leads to chronic hepatitis C and hepatocellular cancer.
Li
Bo
B
Department of Pathology, Xiangya Medical School, Central South University, Changsha 410013, China.
Feng
De-yun
DY
Cheng
Rui-xue
RX
He
Qiong-qiong
QQ
Hu
Zhong-liang
ZL
Zheng
Hui
H
Wen
Ji-fang
JF
D017209:Apoptosis / Q000502:physiology*; D002455:Cell Division; D002460:Cell Line; D016174:Hepacivirus / Q000737:chemistry*; D022781:Hepatocytes / Q000166:cytology* / Q000821:virology*; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D014758:Viral Core Proteins / Q000494:pharmacology*
D016328:NF-kappa B; D014758:Viral Core Proteins; D020929:Mitogen-Activated Protein Kinase Kinases