Epithelial-to-Mesenchymal Transition

Definition

Epithelial-to-mesenchymal transition (EMT) is a biological process where epithelial cells lose their characteristics, such as cell-cell adhesion and polarity, and gain mesenchymal properties, which include increased motility and invasiveness. This transformation is crucial during various developmental processes, such as cell migration during neural crest formation, the early stages of organ development, and the formation of germ layers. EMT allows cells to adapt to new environments, facilitating important transitions in tissue architecture and function.

5 Must Know Facts For Your Next Test

1. EMT is vital during gastrulation, allowing cells to move from the epiblast layer to form the mesoderm and endoderm germ layers.
2. During neurulation, neural crest cells undergo EMT to detach from the neural tube and migrate throughout the embryo, contributing to various structures including craniofacial features.
3. EMT is also involved in wound healing and fibrosis, where it can lead to excessive scarring if not properly regulated.
4. The process of EMT is often regulated by transcription factors like Snail and Twist, which orchestrate the expression changes needed for this transition.
5. Dysregulation of EMT can lead to pathological conditions, including cancer metastasis, where cancer cells exploit this mechanism to invade other tissues.

Review Questions

• How does epithelial-to-mesenchymal transition facilitate neural crest cell migration?
  • Epithelial-to-mesenchymal transition (EMT) is essential for neural crest cell migration because it enables these cells to change from a stationary epithelial state into a more mobile mesenchymal state. During this process, neural crest cells lose their cell-cell adhesion properties and gain the ability to migrate away from the neural tube. This transition allows them to travel significant distances in the embryo, leading to the formation of various structures such as neurons, glia, and craniofacial elements.
• What role does EMT play in the early stages of organogenesis?
  • In the early stages of organogenesis, epithelial-to-mesenchymal transition (EMT) is critical for the development of organs as it allows for the reorganization of cells into different shapes and structures. For example, during kidney development, cells must undergo EMT to form tubules from the epithelial structures. This process helps establish the intricate architectures necessary for organ function by enabling cells to migrate, proliferate, and differentiate into specialized cell types.
• Evaluate how the understanding of EMT can contribute to therapies targeting cancer metastasis.
  • Understanding epithelial-to-mesenchymal transition (EMT) is crucial for developing therapies aimed at cancer metastasis because it reveals how tumor cells acquire invasive properties. By identifying key molecular players involved in EMT, such as specific transcription factors or growth factors that trigger this transition, researchers can create targeted treatments that inhibit these pathways. This approach may prevent cancer cells from transitioning into a mesenchymal state, thereby reducing their ability to invade surrounding tissues and spread throughout the body, ultimately improving patient outcomes.

Related terms

Mesenchymal Cells: Cells that are characterized by their ability to migrate and differentiate into various cell types, playing a key role in tissue repair and development.

Cadherins:

A family of proteins that mediate cell-cell adhesion in epithelial tissues; during EMT, the expression of certain cadherins decreases, contributing to the loss of adhesive properties.

Growth Factors: Signaling molecules that regulate cellular processes like proliferation, differentiation, and migration; they play a critical role in initiating EMT by activating specific signaling pathways.