E-cadherin but not N-cadherin expression is correlated with the intracellular distribution of catenins in human hepatocellular carcinomas.

Cadherins are Ca2+-dependent cell-cell adhesion molecules, and are involved in the formation and maintenance of the histo-architecture. Using a combination of biochemical and immunohistochemical methods, we analyzed the expression of the cadherin-catenin complex in 34 human hepatocellular carcinomas. Unexpectedly, we found the expression of N (neural)-cadherin in normal hepatocytes and all hepatocellular carcinomas examined. In 18 cases, the decreased expression of E (epithelial)-cadherin was observed. Among them, the decreased expression of alpha-catenin and gamma-catenin (plakoglobin) was also observed in 9 and 6 cases, respectively. Thus the decreased expression of alpha-catenin and gamma-catenin was apparently preceded by the decreased expression of E-cadherin. The decreased expression of beta-catenin was not observed in any of the cases analyzed. beta-Catenin was found to accumulate in the cytoplasm of hepatocellular carcinomas with the decreased expression of E-cadherin, despite the presence of N-cadherin at the cell-cell contacts. These results suggest a pivotal role of E-cadherin in the intracellular distribution of catenins in hepatocellular carcinomas.