A facile assay of epithelial-mesenchymal transition based on cooperativity quantification of cellular autonomous motions

Epithelial-mesenchymal transition (EMT), a qualitative change in cell migration behavior during cancer invasion and metastasis, is becoming a new target for anticancer drugs. Therefore, it is crucial to develop in vitro assays for the evaluation of the abilities of drug candidates to control EMT progression. We herein report on a method for the quantification of the EMT based on particle image velocimetry and correlation functions. The exponential fitting of the correlation curve gives an index (λ), which represents transforming growth factor (TGF)-β1-induced EMT progression and its suppression by inhibitors. Moreover, real-time monitoring of the λ value illustrates a time-dependent EMT progressing process, which occurs earlier than the bio-chemical changes in an EMT marker protein expression. The results demonstrate the usefulness of the present method for kinetic studies of EMT progression as well as EMT inhibitor screening.