The Transcription Factor Snail Controls Epithelial–mesenchymal Transitions by 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–mesenchymal transitions are also determinants of the progression of carcinomas, occurring 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 fibroblastoid phenotype and acquire tumorigenic and invasive properties. Endogenous 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 considered as a marker for malignancy, opening up new avenues for the design of specific anti-invasive drugs.