EFFECT OF CALCIUM ON E-CADHERIN EXPRESSION IN BREAST-TUMOR CELLS

E-cadherins are homophilic adhesion molecules the expression of which is tightly linked to the invasiveness and the differentiated state of the cells. E-cadherin expression seems also inversely related to the e xpression of vimentin, an intermediate filament implicated in the meta static potential of some cells. In breast tumor cells MCF-7, we have p reviously shown that calcium influences cell growth and promotes cell differentiation. In view of the importance of cell adhesion mechanisms in cell growth and invasion, we sought to determine whether calcium a ffects the regulation of E-cadherin expression and modifies the relati onship between E-cadherin and vimentin expression. To address this que stion, cells were grown at low (0.04 mM) or high (2.5 mM) concentratio n of calcium and cadherin and vimentin expression was assessed by flow cytometry analyses. Our results show that calcium enhances cadherin e xpression in cadherin positive cells and decreases vimentin expression in these cells; in cadherin negative cells, calcium only decreases th e expression of vimentin. The modifications of E-cadherin and/or vimen tin expression suggests that drugs that can modify intracellular calci um may contribute to overcoming the progression of breast tumor cells toward increasingly malignant phenotypes.