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

Abstract

Objectives. The cadherin/catenin adhesion complex is fundamentally involved in epithelial cancer invasion and metastasis. Much evidence suggesting that epidermal growth factor (EGF) induced the scattering and invasion of cancer cells, probably by affecting E-cadherin function, has been reported. The present study aimed to confirm the hypothesis that EGF/epidermal growth factor receptor (EGFR) was related with the E-cadherin adhesion system in cervical cancer cells and that EGF might induce tyrosine phosphorylation of β- and γ-catenin. Methods. Cervical cancer cells were treated for different time durations with 30 ng/ml of EGF. Alteration of the cell morphology was examined by light microscopy and the expression of E-cadherin, β-catenin, γ-catenin, EGFR, and activated EGFR was assayed using Western blotting. Tyrosine phosphorylation of β- and γ-catenin was also examined using immunoprecipitation. 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-cadherin and β- and γ-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 activated EGFR and tyrosine phosphorylation of β- and γ-catenin was found. Conclusions. EGF-induced scattering of the E-cadherin-positive cervical cancer cells might be the result of tyrosine phosphorylation of the β- and γ-catenin. Phosphorylation of the β- and γ-catenin may hamper the adhesive function of the E-cadherin-catenin complex, © 2001 Academic Press.