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Vol. 19, Issue 3, 945-956, March 2008
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University of Montpellier, Centre National de la Recherche Scientifique, Institut de Génétique Moléculaire de Montpellier, 34293 Montpellier Cedex 5, France
Submitted September 25, 2007;
Revised October 31, 2007;
Accepted December 10, 2007
Monitoring Editor: Carl-Henrik Heldin
Transforming growth factor β (TGF-β) has a strong impact on liver development and physiopathology, exercised through its pleiotropic effects on growth, differentiation, survival, and migration. When exposed to TGF-β, the mhAT3F cells, immortalized, highly differentiated hepatocytes, maintained their epithelial morphology and underwent dramatic alterations of adhesion, leading to partial or complete detachment from a culture plate, followed by readhesion and spreading. These alterations of adhesive behavior were caused by sequential changes in expression of the
5β1 integrin and of its ligand, the fibronectin. The altered specificity of anchorage to the extracellular matrix gave rise to changes in cells' collective motility: cohorts adhering to fibronectin maintained a persistent, directional motility, with ezrin-rich pathfinder cells protruding from the tips of the cohorts. The absence of adhesion to fibronectin prevented the appearance of polarized pathfinders and lead to random, oscillatory motility. Our data suggest a novel role for TGF-β in the control of collective migration of epithelial cohorts.
Address correspondence to: Urszula Hibner (ula.hibner{at}igmm.cnrs.fr)