Slug is required for cell survival during partial epithelial-mesenchymal transition of HGF-induced tubulogenesis

Transcription factors of the Snail family are key regulators of epithelial-mesenchymal transition (EMT). In many processes during development or disease, cells do not acquire all the characteristics associated with EMT, leading to what we refer to as partial EMT (p-EMT). However, little is known of the implications of the Snail transcription factors in processes that only involve a p-EMT. To assess this, we used the hepatocyte growth factor (HGF)-induced Madin-Darby canine kidney tubulogenesis system, which provides a three-dimensional culture model of a morphogenetic process including a p-EMT. We found that although Slug (Snail2) is highly and transitory up-regulated during the p-EMT phase of tubulogenesis, it is not a repressor of E-cadherin during this process. Using inducible knockdown of Slug, we demonstrate that Slug is not an inducer of cell movement and instead is required for survival during p-EMT. We conclude that in epithelial cells, promoting cell survival can be a primary function of Slug, rather than being acquired concomitantly with EMT.