ABSTRACT
The purpose of this study is to investigate if the EGFR-Stat3 signal pathway contributes to the carcinogenesis of hepatoma in rats. Hepatoma was induced in rats by 3'Me-DAB as a model. EGFR, TGFalpha, Stat3, p-Stat3 in different stages of carcinogenesis were detected by immunohistochemistry and Western blot. In situ hybridization was applied to investigate the expression of Stat3 mRNA. The expressions of signal molecules were assessed by KS400 Image Analysis system. The data were statistically evaluated. EGFR, TGFalpha, Stat3 were highly expressed in the stages of liver necrosis and repairment. All hepatocellular carcinoma cases revealed elevated expression of EGFR, TGFalpha. Elevation of Stat3 mRNA and protein levels were identified, increase of activation of Stat3 was also observed. In HCC, there was positive correlation between p-Stat3 level and the expression of TGFalpha and PCNA. Increased expression of Bcl-2 (P < 0.05) coincided with elevated level of p-Stat3. Therefore, the EGFR-Stat3 signal pathway was related to the development of hepatoma in rats. TGFalpha-EGFR autocrine ring formation may lead to the activation of Stat3 and in turn, promote proliferation and regulate the transcription of genes regulating cell apoptosis and cell cycle.
Subject(s)
Carcinoma, Hepatocellular/metabolism , ErbB Receptors/metabolism , Liver Neoplasms, Experimental/metabolism , Proliferating Cell Nuclear Antigen/metabolism , STAT3 Transcription Factor/metabolism , Signal Transduction , Animals , Apoptosis , Carcinoma, Hepatocellular/chemically induced , Carcinoma, Hepatocellular/pathology , Carcinoma, Hepatocellular/physiopathology , Cell Cycle , Cell Transformation, Neoplastic/metabolism , Disease Models, Animal , Immunohistochemistry , In Situ Hybridization , Liver Cirrhosis/metabolism , Liver Neoplasms, Experimental/chemically induced , Liver Neoplasms, Experimental/pathology , Liver Neoplasms, Experimental/physiopathology , Male , Models, Biological , Phosphorylation , Proto-Oncogene Proteins c-bcl-2/metabolism , RNA, Messenger/genetics , Rats , Rats, Wistar , STAT3 Transcription Factor/genetics , Transforming Growth Factor alpha/metabolism , p-Dimethylaminoazobenzene/analogs & derivativesABSTRACT
AIM: Initial report on the in situ examination of the mRNA expression of transforming growth factor betas (TGFbetas), TGFbeta type II receptor (TbetaRII) and telomerase activity in the experimental rat liver tissue during cholangiocarcinogenesis. METHODS: Rat liver cholangiocarcinogenesis was induced by 3'-methyl 4-dimethylazobenzene (3'Me-DAB). In situ hybridization was used to examine the TGFbetas) and TGFbeta type II receptor (TbetaRII) mRNA, in situ TRAP was used to check the telomerase activity in the tissue samples. RESULTS: There was no TGFbetas, TbetaRII mRNA expression or telomerase activity in the control rat cholangiocytes. The expression of TGFbeta1, TbetaRII was increased in regenerative, hyperplastic, dysplastic cholangiocytes and cholangiocarcinoma (CC) cells. The expression of TGFbeta2 mRNA was observed in only a part of hyperplastic, dysplastic cholangiocytes. TGFbeta3 expression was very weak, only in hyperplastic lesion. There was positive telomerase activity in the regenerative, hyperplastic, dysplastic cholangiocytes, and CC cells. Stroma fibroblasts of these lesions also showed positive TGFbetas, TbetaRII mRNA expression and telomerase activity. CONCLUSION: There were TGFbetas, TbetaRII expression and telomerase activity in hyperplastic, dysplastic cholangiocytes, cholangiocarcinoma cells as well as in stroma fibroblasts during cholangiocarcinogenesis. Their expression or activity is important in cholangiocarcinogenesis andstroma formation.
Subject(s)
Cholangiocarcinoma/metabolism , RNA, Messenger/metabolism , Receptors, Transforming Growth Factor beta/genetics , Telomerase/metabolism , Transforming Growth Factor beta/genetics , Animals , Azo Compounds , Benzene Derivatives , Cholangiocarcinoma/chemically induced , Male , Protein Serine-Threonine Kinases , Rats , Rats, Wistar , Receptor, Transforming Growth Factor-beta Type IIABSTRACT
AIM:To investigate the application of confocal laser scanning microscopy (CLSM) in tumor pathology and three-dimensional (3-D) reconstruction by CLSM in pathologic specimens of hepatocellular carcinoma (HCC).METHODS:The 30&mgr;m thick sections were cut from the paraffin embedded tissues of HCC, hyperplasia and normal liver,stained with DNA fluorescent probe YOYO-1 iodide and examined by CLSM to collect optical sections of nuclei and 3-D images reconstructed.RESULTS:HCC displayed chaotic arrangement of carcinoma cell nuclei, marked pleomorphism, indented and irregular nuclear surface, and irregular and coarse chromatin texture.CONCLUSION:The serial optical tomograms of CLSM can be used to create 3-D reconstruction of cancer cell nuclei. Such 3-D impressions might be helpful or even essential in making an accurate diagnosis.