Diversity in the molecular and cellular strategies of epithelium-to-mesenchyme transitions: Insights from the neural crest

Controlled levels of canonical Wnt signaling are required for neural crest migration

“…NC cells are subdivided into cranial (Graham et al, 2004;Cordero et al, 2011), cardiac (Kirby et al, 1983;Keyte and Hutson, 2012), vagal (Kuo and Erickson, 2011;Peters-Van Der Sanden et al, 1993;Burns and Le Douarin, 1998;Yntema and Hammond, 1954), trunk (Bronner-Fraser and Fraser, 1989;Serbedzija et al, 1994) and sacral (Burns and Le Douarin, 1998;Anderson et al, 2006) NC cells due to their diversity along neuraxis ( Fig.1.1A). Upon closure of the neural plate, NC cells undergo epithelial-to-mesenchymal transition (EMT) (Ahlstrom and Erickson, 2009;Alfandari et al, 2010;Berndt et al, 2008 andDuband, 2010) allowing them to delaminate from prospective neural tube and migrate throughout the embryo ( Fig.1.1B). Many of the genes involved in EMT of NC cells are transcription factors which have been also classified as proto-oncogenes contributing to cancer development (Thiery, 2003).…”

“…The core of EMT is the breakdown of the highly integrated epithelium and formation of the mesenchymal cells causing complex tissue rearrangements common in early embryogenesis and tumor metastasis ( Fig.1.5) (Nieto, 2011;Thiery et al, 2009). During EMT cells can go through the series of transient stages, from typical epithelial tissues with firm cell-cell adhesions, to not fully determined mesenchymal cells with transient contacts and finally to the entirely separated mesenchymal cell without epithelial polarity and cell-cell adhesions Ahlstrom and Erickson, 2009;Baum et al, 2008;Duband, 2010;Theveneau and Mayor, 2012 (Vallin et al, 2001;Yook et al, 2006;Thiery and Sleeman, 2006) and numerous transcription factors belonging to the group of NC-specifires.…”

The neural crest

“…Both NC cells and cancer cells are known to migrate as solitary cells or collective groups, relying on chemotaxis and metalloproteinases, as well as interaction with their surrounding tissues. Furthermore, numerous signalling pathways and transcription factors involved in NC development have been found to be instrumental in cancer progression, suggesting that some tumours might recapitulate part of NC development in a dysregulated manner (Duband, 2010;Kerosuo and Bronner-Fraser, 2012;Lim and Thiery, 2012;Theveneau and Mayor, 2012;Thiery et al, 2009).…”

“…NC cell migration begins with a complete or partial EMT, which allows NC cells to separate from the neuroepithelium and the ectoderm (Duband, 2010;Theveneau and Mayor, 2012). A global switch from E-cadherin (cadherin 1) to N-cadherin (cadherin 2) expression occurs at the time of neural induction (Dady et al, 2012;Nandadasa et al, 2009) and thus neural plate and all pre-migratory NC cells express high levels of N-cadherin, with some residual levels of E-cadherin mostly found in the cephalic region.…”

Transcriptional and Epigenetic Regulation of Neural Crest Induction during Neurulation

“…NCCs separate from neighboring neuroepithelial cells by delamination, which involves a partial or complete EMT [19] . At delamination, the tissue splits into separate populations.…”