FH535 Potentiation of Cigarette Smoke Condensate Cytotoxicity is Associated With Changes in β-Catenin and EGR-1 Signaling

Cigarette smoke condensate (CSC) has been reported to elicit morphological and transcriptional changes that suggest epithelial-to-mesenchymal transition (EMT) in cultured bronchial epithelial cells. The transdifferentiation potential of acute and prolonged CSC exposure alone or in combination with the b-catenin inhibitor, FH535, was investigated in the bronchial epithelial cell line, BEAS-2B, through assessment of cell morphology, transcript expression, protein expression, and protein localization. Changes in morphology, b-catenin translocation, E-cadherin expression, metalloproteinase expression, and fibronectin could be demonstrated independent of molecular or physiological evidence of EMT. FH535 was shown to increase CSC-induced cytotoxicity and depress b-catenin expression. However, FH535 effects were not limited to the b-catenin pathway as it also blocked the expression of early growth responsive protein 1 (EGR-1) target genes, fibronectin and phosphatase and tensin homologue, without affecting EGR-1 nuclear accumulation