Cellular morphologies, motility, and epithelial–mesenchymal transition of breast cancer cells incubated on viscoelastic gel substrates in hypoxia

The induction of epithelial–mesenchymal transition (EMT) is believed to promote tumor cell motility and invasion. Using polymeric gel substrates with different viscoelasticity as microenvironment of cell culture substrates that influences cancer progression and metastatic potential, we have examined the effect of the viscoelasticity on the direct relation between cellular motility and mesenchymal properties with induction of EMT in MDA-MB-231 cells. The MDA-MB-231 cells cultured on gel substrates showed different cellular morphologies, and these morphological differences were robustly correlated with cellular migration speed (S) and damping coefficient (tanδ) of gel substrates (not substrate stiffness). The linkage between the acquisition of the mesenchymal phenotype in the cells through the induction of EMT mediated by a stiffer substrate and the promotion of cellular motility was not observed. Understanding the biology of EMT with or without linkage to cellular motility provides new approaches in development of new therapeutic strategies.