Korean J Pathol.  2003 Apr;37(2):121-128.

Expression of TGF-beta1 and TGF-betatype II Receptor in Chemically Induced Hepatocarcinogenesis of the Rat

• Park DY
• Park KW
• Suh KS

Abstract

BACKGROUND: Transforming growth factor (TGF)-beta1 inhibits hepatocyte proliferation by inducing apoptosis. Expression of TGF-beta1 is tightly associated with the TGF-betatype II receptor (TGR2) expression level, and has been regarded as an important change of TGF-beta1 and TGR2 during hepatocarcinogenesis. We investigated the gene expressions and protein localizations of TGF-beta1 and TGR2 in chemical hepatocarcinogenesis.
METHODS
Solt and Farber's method was used as the chemical hepatocarcinogenesis model of the rat. Northern blot analyses and immunohistochemistry for TGF-beta1 and TGR2 were performed to investigate the gene expressions and protein localizations, respectively.
RESULTS
The Northern blot analyses showed a slight increase of TGF-beta1 transcripts one month after partial hepatectomy, which is more than in sham operated control liver, and a decrease of transcripts for TGR2 two months after partial hepatectomy. The number of TGF-beta-positive preneoplastic hepatocytes was increased and correlated with the increase of the number of TGR2 negative hepatocytes or reduction of expressions of TGR2 in preneoplastic lesions. HCC tissues showed an increase of TGF-beta1 protein expressions and a decrease of TGR2 compared to the adjacent liver parenchyme.
CONCLUSION
Our data suggest that down regulation of TGR2 in preneoplastic lesions and HCC might contribute to the resistance to the growth inhibitory effects of TGF-beta.

MeSH Terms

Animals
Apoptosis
Blotting, Northern
Down-Regulation
Gene Expression
Hepatectomy
Hepatocytes
Immunohistochemistry
Liver
Rats*
Transforming Growth Factor beta
Transforming Growth Factor beta1*
Transforming Growth Factors
Transforming Growth Factor beta
Transforming Growth Factor beta1
Transforming Growth Factors