Abstract Discovering novel drugs for epithelial tumors remains a challenge since cellular events underlying the onset of carcinoma progression are largely unknown. We previously reported the therapeutic effects of oral 5′-methylthioadenosine in the Abcb4−/− mouse (Latasa et al, PLoS ONE 2010: e15690), a clinically relevant model of chronic liver disease leading to carcinoma development. Aiming to gain insight into malignant cellular traits, we then generated primary cultures of intrahepatic bile duct cells from this Abcb4−/− mouse model. We found that Abcb4−/−-cholangiocytes exhibit a fibroblastoid-like appearance which is accompanied by diminished expression of epithelial hallmarks (CK19), and a concomitant up-regulation of mesenchymal markers such as Snail1. The trans-epithelial-electrical-resistance analyses indicated that whereas confluent monolayers of normal cholangiocytes retained the epithelial polarity, Abcb4−/−-cholangiocytes fail to repolarize. Abcb4−/−-cholangiocytes proliferated at reduced growth rates (p<0.05), formed a higher number of colonies in soft agar (p<0.01) and were less sensitive to antiproliferative effect of TGFβ1 (p<0.05). Consistent with EMT characteristics, Abcb4−/−-cholangiocytes induced TGFβ isoforms and were more sensitive to TGFβ1-signaling. Collectively, this data suggests that Abcb4−/− cholangiocytes acquire EMT features that may be largely regulated in vivo by TGFβ1. This original bile ductular cell line of Abcb4−/−-cholangiocytes will be useful for testing compounds that may interfere with metastatic malignancy of EMT. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2422. doi:1538-7445.AM2012-2422