Epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT) is a biological process that allows a polarized epithelial cell, which normally functions to form the lining of certain body cavities and structures, to undergo biochemical changes that enable it to assume a mesenchymal cell phenotype. This transformation involves enhanced migratory capacity, invasiveness, elevated resistance to apoptosis, and greatly increased production of extracellular matrix components. The completion of EMT is signaled by the degradation of underlying basement membrane and the formation of a mesenchymal cell that can migrate away from the epithelial layer in which it originated.

Overview

EMT is crucial for numerous developmental processes including mesoderm formation and neural tube formation. In adults, EMT is implicated in the pathogenesis of various disease processes, such as fibrosis, wound healing, and the progression of cancer to invasive metastatic disease.

Mechanism

The process of EMT is regulated by a number of signaling pathways and transcription factors including transforming growth factor beta (TGF-β), Wnt, and Notch. These pathways induce the expression of specific transcription factors such as Snail, Slug, and Twist, which in turn repress epithelial markers like E-cadherin, a critical molecule for cell-cell adhesion in epithelial cells, and promote the expression of mesenchymal markers like N-cadherin and vimentin.

Clinical Significance

In the context of cancer, EMT is associated with the acquisition of metastatic capabilities, resistance to chemotherapy, and the generation of cancer stem cells. This has made EMT a target of interest for developing novel therapeutic strategies aimed at preventing cancer progression and metastasis.

Research

Research in the field of EMT continues to evolve, focusing not only on its implications in cancer but also on its reversible counterpart, mesenchymal-epithelial transition (MET), which is critical for the formation of organ structures during embryonic development and in tissue regeneration.

See Also

• Cancer metastasis
• Cell migration
• Developmental biology