ENHANCED E-CADHERIN EXPRESSION IN EPIDERMAL GROWTH-FACTOR RECEPTOR-EXPRESSING CELLS

Expression of the epidermal growth factor receptor (EGFr) and the cell -cell adhesion molecule E-cadherin have individually been implicated i n the biological activity of the most common human malignancies. There is also evidence for colocalization and for a correlation in the expr ession of these two proteins in human cells. To better define the rela tionship between these two gene products, we used immunohistochemistry and Western blot analysis to compare E-cadherin expression in various well characterized cell lines lacking expression of EGFr or expressin g wild type, functional mutant or non functioning mutant EGFr. Parenta l NR6 cells, which lack endogenous EGFr, and a derivative cell line NR 6M721, which expresses EGFr lacking tyrosine kinase activity, showed l ow levels of E-cadherin expression with or without stimulation with EG F. In contrast, the derivative NR6c'973 cell fine, which expresses an active EGFr defective in EGF induced internalization and down-regulati on and NR6 cells expressing wild type EGFr showed strong E-cadherin ex pression. These results suggest that EGFr activation may regulate or e nhance E-cadherin expression. (C) 1995 Academic Press, Inc.