Analysis of TGF-β1-and drug-induced epithelial-mesenchymal transition in cultured alveolar epithelial cell line RLE/Abca3

In this study, we examined the induction of epithelial-mesenchymal transition (EMT) by transforming growth factor (TGF)-beta 1 and drugs in genetically engineered type II alveolar epithelial cell line RLE/Abca3. Treatment of RLE/Abca3 cells with TGF-beta 1 induced marked changes in cell morphology from epithelial-like to elongated fibroblast-like morphology. With these morphological changes, mRNA expression of epithelial markers such as cytokeratin 19 (CK19) decreased, while that of mesenchymal markers such as alpha-smooth muscle actin (alpha-SMA) increased. TGF-beta 1 treatment also decreased the mRNA expression of Abca3, a type II cell marker, and formation of lamellar body structures. Interestingly, the effect of TGF-beta 1 on Abca3 mRNA expression was observed in RLE/Abca3 cells, but not in wild-type RLE-6TN, A549, and H441 cells. Treatment of RLE/Abca3 cells with bleomycin (BLM) and methotrexate (MTX) induced similar morphological and mRNA expression changes. In addition, the increase in alpha-SMA and the decrease in Abca3 mRNA expression by these drugs were observed only in RLE/Abca3 cells. These findings suggest that, like TGF-beta 1, BLM and MTX induce EMT in RLE/Abca3 cells, and RLE/Abca3 cells would be a good model to study drug-induced EMT. The effect of pirfenidone, an antifibrotic and anti-inflammatory drug, on EMT induced by TGF-beta 1 was also discussed. Copyright (C) 2014, The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.