Epithelial-mesenchymal transition of breast cancer cells activated by SNAIL1 transcription factor

Abstract

Cancer cells use the program of epithelial-mesenchymal transition for initiation of the invasion-metastasis cascade. Using confocal and video-microscopy, in breast cancer MCF-7 cells undergoing Snail1-induced epithelial-mesenchymal transition reorganization of cytoskeleton was studied. We used the line of MCF-7 cells stably expressing tetOff SNAI1 construct (MCF-7-SNAI1 cells). After tetracycline washing and Snail1 activation MCF-7-SNAI1 cells underwent EMT and acquired a migratory phenotype retaining expression of E-cadherin. We identified five variants of the mesenchymal phenotype, differing in cell morphology and migration rate. Migrating cells had high degree of plasticity which allowed them to quickly change both the phenotype and the speed of movement. The changes of phenotype of MCF-7-SNAI1 cells are based on Arp2/3-mediated branched actin polymerization in lamellipodia, myosin-based contractility in the zone behind the nucleus, redistribution of adhesive proteins from cell-cell contacts to the leading edge and reorganization of intermediate keratin filaments.