title: Bile acids activate EGF receptor via a TGF-alpha-dependent mechanism in human cholangiocyte cell lines.
abstract: Bile acids transactivate the EGF receptor (EGFR) in cholangiocytes. However, the mechanisms by which bile acids transactivate the EGFR remain unknown. Our aims were to examine the effects of bile acids on EGFR activation in human cholangiocyte cell lines KMBC and H-69. Bile acids stimulated cell growth and induced EGFR phosphorylation in a ligand-dependent manner. Although cells constitutively expressed several EGFR ligands, only transforming growth factor-alpha (TGF-alpha) antisera effectively blocked bile acid-induced EGFR phosphorylation. Consistent with the concept that matrix metalloproteinase (MMP) activity is requisite for TGF-alpha membrane release and ligand function, bile acid transactivation of EGFR and cell growth was blocked by an MMP inhibitor. In conclusion, bile acids activate EGFR via a TGF-alpha-dependent mechanism, and this EGFR activation promotes cellular growth.
authors.affiliation: Mayo Medical School, Clinic, and Foundation, 200 First Street SW, Rochester, MN 55905, USA. gores.gregory@mayo.edu
authors.forename: Nathan W
authors.initials: NW
authors.lastname: Werneburg
authors.forename: Jung-Hwan
authors.initials: JH
authors.lastname: Yoon
authors.forename: Hajime
authors.initials: H
authors.lastname: Higuchi
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Gores
mesh_terms: D001647:Bile Acids and Salts / Q000378:metabolism / Q000494:pharmacology*; D001650:Bile Duct Neoplasms; D001653:Bile Ducts, Intrahepatic / Q000166:cytology* / Q000201:enzymology; D000081247:CSK Tyrosine-Protein Kinase; D002461:Cell Line, Transformed; D018281:Cholangiocarcinoma; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D008024:Ligands; D020782:Matrix Metalloproteinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D016211:Transforming Growth Factor alpha / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D019061:src-Family Kinases
chemical_list: D001647:Bile Acids and Salts; D008024:Ligands; D016211:Transforming Growth Factor alpha; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; D020782:Matrix Metalloproteinases