RESUMO
<p><b>OBJECTIVE</b>Malignant transformation of epithelial cell frequently coincides with loss of E-cadherin. Here we study the expression of Snail and E-cadherin and correlate their expression with cell differentiation and in vitro invasion.</p><p><b>METHODS</b>The expression and localization of Snail and E-cadherin were studied by Northern blot and laser confocal microscopy in two normal cell lines (MDCK, NIH 3T3) and six carcinoma cell lines (A431, MCF-7, MDA-MB-453, HepG2, MDA-MB-435s, MDA-MB-231). Boyden chamber assay was done to detect the invasive ability of cells in vitro.</p><p><b>RESULTS</b>Snail mRNA and protein were detected in fibroblasts NIH 3T3 and poorly differentiated carcinoma cell lines HepG2, MDA-MB-435s and MDA-MB-231. On the contrary, E-cadherin mRNA and protein were detected in normal epithelial cell line MDCK and well differentiated carcinoma cell lines A431 and MDA-MB-453. In MCF-7 cells, Snail and E-cadherin expressions were revealed both at mRNA and protein levels. The cells with higher expression of Snail had stronger ability of invasion than those with lower expression of Snail.</p><p><b>CONCLUSION</b>There is an inverse correlation between Snail and E-cadherin expressions and their expressions are correlated with cell differentiation and tumor invasiveness.</p>