title: Epithelial-mesenchymal transition and FOXA genes during tobacco smoke carcinogen induced transformation of human bronchial epithelial cells.
abstract: Lung cancer is largely an environmentally caused disease with poor prognosis. An in vitro transformation model of human bronchial epithelial cells (HBEC) was used to study long-term effects of tobacco smoke carcinogens on epithelial-mesenchymal transition (EMT) and the forkhead box transcription factors FOXA1 and FOXA2. CDK4 and hTERT immortalized HBEC2 and HBEC12 cell lines were exposed weekly to either cigarette smoke condensate (CSC), benzo[a]pyrene, or methylnitrosourea. Transformed cell lines were established from soft-agar colonies after 12weeks of exposure. HBEC12 was transformed by all exposures while HBEC2 was only transformed by CSC. Untransformed HBEC2 showed little invasive capacity, whereas transformed cell lines completely closed the gap in a matrigel scratch wound assay. CDH1 was down-regulated in all of the transformed cell lines. In contrast, CDH2 was up-regulated in both HBEC2 and one of the HBEC12 transformed cell lines. Furthermore, transformed cells showed activation of EMT markers including SNAI1, ZEB1, VIM, and MMP2. All transformed cell lines had significant down-regulation of FOXA1 and FOXA2, indicating a possible role in cell transformation and EMT. ChIP analysis showed increased binding of Histone-H3 and macroH2A in FOXA1 and FOXA2 in the transformed HBEC2 cell lines, indicating a compact chromatin. In conclusion, long-term carcinogen exposure lead to down-regulation of FOXA1 and FOXA2 concomitantly with the occurrence of EMT and in vitro transformation in HBEC cells.
authors.affiliation: Section for Toxicology and Biological Working Environment, Department of Biological and Chemical Working Environment, National Institute of Occupational Health, N-0033 Oslo, Norway.
authors.forename: Audun
authors.initials: A
authors.lastname: Bersaas
authors.affiliation: Section for Toxicology and Biological Working Environment, Department of Biological and Chemical Working Environment, National Institute of Occupational Health, N-0033 Oslo, Norway.
authors.forename: Yke Jildouw
authors.initials: YJ
authors.lastname: Arnoldussen
authors.affiliation: Section for Toxicology and Biological Working Environment, Department of Biological and Chemical Working Environment, National Institute of Occupational Health, N-0033 Oslo, Norway.
authors.forename: Mari
authors.initials: M
authors.lastname: Sjøberg
authors.affiliation: Section for Toxicology and Biological Working Environment, Department of Biological and Chemical Working Environment, National Institute of Occupational Health, N-0033 Oslo, Norway.
authors.forename: Aage
authors.initials: A
authors.lastname: Haugen
authors.affiliation: Section for Toxicology and Biological Working Environment, Department of Biological and Chemical Working Environment, National Institute of Occupational Health, N-0033 Oslo, Norway. Electronic address: steen.mollerup@stami.no.
authors.forename: Steen
authors.initials: S
authors.lastname: Mollerup
mesh_terms: D001980:Bronchi / Q000166:cytology; D002273:Carcinogens / Q000633:toxicity*; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000187:drug effects; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D051541:Hepatocyte Nuclear Factor 3-alpha / Q000235:genetics*; D051542:Hepatocyte Nuclear Factor 3-beta / Q000235:genetics*; D006801:Humans; D012906:Smoke / Q000009:adverse effects*
chemical_list: D002273:Carcinogens; C496499:FOXA1 protein, human; C496502:FOXA2 protein, human; D051541:Hepatocyte Nuclear Factor 3-alpha; D012906:Smoke; D051542:Hepatocyte Nuclear Factor 3-beta
keywords: Benzo[a]pyrene; Cigarette smoke condensate; EMT; Gene expression; In vitro transformation; Lung carcinogenesis