[The role of beta-catenin in rat embryonic development and tumorigenesis].

ABSTRACT

OBJECTIVE: To investigate the role of beta-catenin as a key element of Wnt/beta-catenin signaling pathway in the development of embryonic liver and liver tumorigenesis. METHODS: Immunohistochemical method was used to examined beta-catenin proteins in 12-day (E12), 16-day (E16) embryonic rat liver, neonate rat liver, and in adult rat liver as well as in rat hepatoma. Beta-catenin mRNA was amplified in the above-mentioned samples by means of semiquantitative RT-PCR. RESULTS: Beta-catenin proteins were found in cytoplasm of E12 and E16 embryonic liver as well as in hepatoma. The expression level of beta-catenin protein in E12 embryonic liver was higher than that in E16. There were much more positive cells in E12 embryonic liver than in E16. However, no positive cell was observed expressing beta-catenin proteins in neonate rat liver and adult rat liver. The quantity of beta-catenin mRNA was the same in all samples. CONCLUSION: Wnt/beta-catenin signaling pathway was open during the development of embryonic liver and hepatic tumorigenesis. The accumulation of beta-catenin proteins in cytoplasm of embryonic liver and rat hepatic carcinoma cells might be caused not by the elevation of transcription of beta-catenin gene but by the avoidance of degeneration of beta-catenin protein.