ИСТИНА

Cancer cells use the program of epithelial-mesenchymal transition (EMT) for initiation of the invasion-metastasis cascade. Using confocal and video-microscopy, reorganization of the cytoskeleton was studied in the MCF-7 breast cancer cells undergoing Snail1- induced EMT. We used the line of MCF-7 cells stably expressing tetoff SNAI1 construct (MCF-7-SNAI1 cells). After tetracycline washout and Snail1 activation MCF-7-SNAI1 cells underwent EMT and acquired a migratory phenotype while retaining expression of E-cadherin. We identified five variants of the mesenchymal phenotype, differing in cell morphology and migration velocity. The changes of the phenotype of MCF-7-SNAI1 cells are based on the Arp2/3-mediated actin network polymerization in lamellipodia, formation of actin-myosin bundles, their rearward flow and contractility, redistribution of adhesive proteins from cell-cell contacts to the leading edge, and reorganization of intermediate keratin filaments. Migrating cells possessed a high degree of plasticity quickly changing both the phenotype and the migration velocity driven by reorganization of the actin cytoskeleton. The study was financially supported by the RSF grant # 22-15-00347.