The transcription factor Snail controls epithelial-mesenchymal transitionsby repressing E-cadherin expression

The Snail family of transcription factors has previously been implicated in the differentiation of epithelial cells into mesenchymal cells (epithelial -mesenchymal transitions) during embryonic development. Epithelial-mesenchy mal transitions are also determinants of the progression of carcinomas, occ urring concomitantly with the cellular acquisition of migratory properties following downregulation of expression of the adhesion protein E-cadherin. Here we show that mouse Snail is a strong repressor of transcription of the E-cadherin gene. Epithelial cells that ectopically express Snail adopt a f ibroblastoid phenotype and acquire tumorigenic and invasive properties. End ogenous Snail protein is present in invasive mouse and human carcinoma cell lines and tumours in which E-cadherin expression has been lost. Therefore, the same molecules are used to trigger epithelial-mesenchymal transitions during embryonic development and in tumour progression. Snail may thus be c onsidered as a marker for malignancy, opening up new avenues for the design of specific anti-invasive drugs.