Co-ordination of epithelial junctional systems, and its disturbance during the development of a malignant phenotype

Abstract

Tissues are dynamic groups of cells with specific functions for each cell type. A disturbed communication between the cells of the same or different type can lead to a variety of diseases, for example cancer. This thesis describes the fading border between adhesion molecules and adhesion receptors. The characteristics of a relatively novel epithelial morphoregulating molecule, Ep-CAM, are presented, as well as its role in tumor biology are reviewed. E-cadherin mediated adhesion complex is abrogated by introduction of Ep-CAM, without involvement of key regulator beta-catenin. The signaling transduction pathway includes activation of Pi3K. Iimmunohistochemistry studies of EpCAM expression in tumors showed that Ep-CAM is a useful diagnostic marker for the identification of neoplastic epithelial changes and tumors of epithelial origin. Furthermore, the effect of Ep-CAM on cadherin mediated adhesions is reversible. The restauration of cadherin mediated adhesions by suppressing the Ep-CAM expression, is of great importance in the quest for new modalities for curing cancer.