Transforming growth factor-β transiently induces vimentin expression and invasive capacity in a canine mammary gland tumor cell line

The epithelial-mesenchymal transition (EMT) is a crucial event that occurs during cancer metastasis and can be induced by transforming growth factor-beta (TGF-beta) in various tumor cells in vitro. However, little is known about the effects of TGF-beta in canine mammary gland tumors (CMGTs). Here, we investigated the role of TGF-beta in CMGT. We observed that treatment of the CMGT cell line CHMp13a with TGF-beta 1 leads to transient induction of the mesenchymal marker vimentin. Real-time measurements of cellular electrical impedance also showed that CMGT invasiveness is transiently increased by TGF-beta 1 treatment, but is reversed after prolonged stimulation. This phenomenon is similar to the mesenchymal-epithelial transition (MET, the reverse phenomenon of EMT), and a process that is implicated in the establishment of secondary metastatic lesions. (C) 2012 Elsevier Ltd. All rights reserved.