Epithelial–mesenchymal transition

Epithelial-mesenchymal transition (EMT) is a developmental program characterized by loss of cell adhesion, repression of E-cadherin expression, and increased cell mobility. EMT is essential for numerous developmental processes such mesoderm formation and neural tube formation.

Several signal transduction pathways, such as Ras-MAPK and Wnt, have been shown to be involved in regulation of EMT. In particular, Ras-MAPK has been shown to activate two related transcription factors known as Snail and Slug. Both of these proteins are transcriptional repressors of E-cadherin and their expression induces EMT. Twist, another transcription factor, has also been shown to induce EMT, and is also implicated in the regulation of metastasis.

Initiation of metastasis involves invasion, which has many phenotypic similarities to EMT, including a loss of cell-cell adhesion mediated by E-cadherin repression and an increase in cell mobility.

Sources

Vernon, A., and LaBonne, C. (2004). Tumor metastasis: a new twist on epithelial-mesenchymal transitions. Current Biology. 14, 719-721.

Yang, J., Mani, S., Donaher, J., Ramaswamy, S., Itzkyson, R., Come, C., Savagner, P., Gitelman, I., Richardson, A., and Weinberg, R. (2004). Twist, a master regulator of morphogenesis, plays an essential role in tumor metastasis. Cell. 117, 927-939.