Expression and tyrosine phosphorylation of E-cadherin, beta- and gamma-catenin, and epidermal growth factor receptor in cervical cancer cells

Objectives. The cadherin/catenin adhesion complex is fundamentally involved in epithelial cancer invasion and metastasis. Much evidence suggesting tha t epidermal growth factor (EGF) induced the scattering and invasion of canc er cells, probably by affecting E-cadherin function, has been reported. The present study aimed to confirm the hypothesis that EGF/epidermal growth fa ctor receptor (EGFR) was related with the E-cadherin adhesion system in cer vical cancer cells and that EGF might induce tyrosine phosphorylation of be ta- and gamma -catenin. Methods. Cervical cancer cells were treated for different time durations wi th 30 ng/ml of EGF, Alteration of the cell morphology was examined by light microscopy and the expression of E-cadherin, beta -catenin, gamma -catenin , EGFR, and activated EGFR was assayed using Western blotting, Tyrosine pho sphorylation of beta and gamma -catenin was also examined using immunopreci pitation. Results. E-cadherin and EGFR were expressed in CaSki, HT-3, and ME-180 cell lines, which showed epithelial contact growth. The expression of E-cadheri n and beta- and gamma -catenin did not change after treatment with EGF, The expression of EGFR decreased and activated EGFR expression increased in 30 min and then decreased subsequently, The simultaneous expression of activa ted EGFR and tyrosine phosphorylation of beta- and gamma -catenin was found . Conclusions. EGF-induced scattering of the E-cadherin-positive cervical can cer cells might be the result of tyrosine phosphorylation of the beta- and gamma -catenin. Phosphorylation of the beta- and gamma -catenin may hamper the adhesive function of the E-cadherin-catenin complex, (C) 2001 Academic Press.