Loss of epithelial differentiation and gain of invasiveness correlates with tyrosine phosphorylation of the E-cadherin/beta-catenin complex in cells transformed with a temperature-sensitive v-SRC gene.

Abstract

Abstract. Loss of histotypic organization of epithelial cells is a common feature in normal development as well as in the invasion of carcinomas. Here we show that the v-src oncogene is a potent effector of epithelial differentiation and invasiveness. MDCK epithelial cells transformed with a temperature-sensitive mutant of v-src exhibit a strictly epithelial phenotype at the nonpermissive temperature for pp60 .... activity (40.5~ but rapidly loose cell-to-cell contacts and acquire a fibroblast-like morphology after culture at the permissive temperature (35~ Furthermore, the invasiveness of the cells into collagen gels or into chick heart fragments was increased at the permissive temperature. The profound effects of v-src on intercellular adhesion were not linked to changes in the levels of expression of the epithelial cell adhesion molecule E-cadherin. Rather, we observed an increase in tyrosine phosphorylation of E-cadherin and, in particular, of the associated protein ~-catenin. These results suggest a mechanism by which v-src counteracts junctional assembly and thereby promotes invasiveness and dedifferentiation of epithelial cells through phosphorylation of the E-cadherin/catenin complex.

Changes in p53 expression can modify cell shape of ras-transformed fibroblasts and epitheliocytes

“…Rhodamine-phalloidin staining did not reveal actin ®bers in ras-transformed Rat1 derivatives (Figure 2b). These changes were similar to those characteristic of oncogene-induced morphological transformations of other epithelial and ®broblastic cell lines (Schenenberger et al, 1991;Behrens et al, 1993).…”

Induction of the adenoma-carcinoma progression and Cdc25A-B phosphatases by the trefoil factor TFF1 in human colon epithelial cells

“…MCF-7 were also cultured under growth factor-free, estrogen-free and hypoxic conditions using the OXOID incubator chamber (Basingtoke, Hamshire, England). The MDCKts.src cell line established after stable transfection of MDCK cells with a thermosensitive mutant of v-src (Behrens et al, 1993) was maintained in DMEM containing 10% FCS. (Emami et al, 2001) and the lipofectAMINE plus reagent (Invitrogen, Cergy-Pontoise, France).…”

Requirement of both mucins and proteoglycans in cell‐cell dissociation and invasiveness of colon carcinoma HT‐29 cells

“…For confocal microscopy, cells grown on plastic or on collagencoated glass coverslips were fixed with 4% paraformaldehyde, quenched with 50 mM NH 4 Cl in PBS for 30 min, permeabilized in saponin 0.2% for 20 min, and then incubated in blocking solution (PBS, 1% BSA, 0.2% saponine) for 30 min. For single labeling of E-cadherin, MUC1, MUC5AC or the heparan-sulfate moiety of proteoglycans, respectively, HECD1 (1/400), 214D4 (1/3), 21M1 (1/250) and HepSS-1 (1/50) in PBS/1% BSA/0.2% saponin were added overnight.…”

“…2 Studies in cancer cell lines have shown that changes in the structure or in the expression of the components of the E-cadherin/␤-catenin complex result in the suppression of cell-cell adhesion and in the expression of an invasive phenotype. [3][4][5][6][7][8] In cancer, the maintenance of the epithelia is lost and dissociation of cells is associated with metastatic dissemination. This phenomenon can occur through a decrease in the expression level of E-cadherin and, regarding colon cancer, such decrease has been related to the tumor grade and clinical outcome.…”