Snail family regulation and epithelial mesenchymal transitions in breast cancer progression.

Since its initial description, the interconversion between epithelial and mesenchymal cells (designed as epithelial-mesenchymal or mesenchymal-epithelial transition, EMT or MET, respectively) has received special attention since it provides epithelial cells with migratory features. Different studies using cell lines have identified cytokines, intercellular signaling elements and transcriptional factors capable of regulating this process. Particularly, the identification of Snail family members as key effectors of EMT has opened new ways for the study of this cellular process.

Erk5 controls Slug expression and keratinocyte activation during wound healing.

Reepithelialization during cutaneous wound healing involves numerous signals that result in basal keratinocyte activation, spreading, and migration, all linked to a loosening of cell-cell adhesion structures. The transcription factor Slug is required for this process, and EGF treatment of human keratinocytes induced activating phosphorylation of Erk5 that coincides with slug transcription. Accordingly, ectopic activation of Erk5 led to increased Slug mRNA levels and faster wound healing, whereas keratinocyte migration was totally blocked by Erk5 pathway inhibition.