Hepatitis B virus X protein activates expression of IGF-IR and VEGF in hepatocellular carcinoma cells.
OBJECTIVE
The expression of insulin-like growth factor I receptor (IGF-IR) and the vascular endothelial growth factor (VEGF) in HepG(2) cells transfected with a hepatitis B virus X (HBx) expression vector was investigated in an attempt to study their possible relationship to the growth of HBx-induced hepatocellular carcinoma (HCC).


METHODS
The eucaryotic expression vector of HBx gene was constructed and introduced into HepG(2) cells. The modified cell HepaG(2)-X was synchronized in a quiescent state by culture of serum deprivation. The IGF-IR and VEGF were analyzed by immunohistochemical and Western blot technique.


RESULTS
The positive rate of IGF-IR expression was 84%A3% in the transfected HBx gene cells, 26%A4% in X(0) control cells. The positive rate of VEGF expressed x cells was 83%A5%, X(0) cells was 28%A6% (P<0.001). The level of IGF-IR and VEGF in serum-starved x modified cells was 1.5 times higher than that of synchronized X(0) modified cells.


CONCLUSIONS
Since the IGF-IR is a very important growth factor in sustaining the tumor abnormal growth and the VEGF has a crucial role in inducting tumor angiogenesis, our findings indicate that HBx may play an important role in the processes of HCC by activating IGF-IR and VEGF gene expression.
Tao
X
X
Chongqing University of Medical Sciences, Chongqing 400016, China.
Shen
D
D
Ren
H
H
Zhang
X
X
Zhang
D
D
Ye
J
J
Gu
B
B
D006528:Carcinoma, Hepatocellular / Q000209:etiology*; D016228:Endothelial Growth Factors / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000209:etiology*; D008222:Lymphokines / Q000032:analysis*; D017526:Receptor, IGF Type 1 / Q000032:analysis*; D015534:Trans-Activators / Q000502:physiology*; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D054334:Viral Regulatory and Accessory Proteins
D016228:Endothelial Growth Factors; D008222:Lymphokines; D015534:Trans-Activators; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D017526:Receptor, IGF Type 1