title: Identification of intracellular pathways through which TGF-β1 upregulates URG-4/URGCP gene expression in hepatoma cells.
abstract: OBJECTIVE
  Up-regulated gene 4 (URG-4/URGCP) was strongly expressed in Hepatitis B infected liver and correlated with HBxAG (Hepatitis B x Antigen) protein and found to promote hepatocellular cancer. Transforming growth factor (TGF-β1) is a multifunctional protein that effects cell proliferation, growth inhibition, differentiation and other functions. However, the mechanism of URG-4/URGCP regulation by TGF-β1 and its significance in cancer progression remains largely unknown.
  
  
  METHODS
  The effect of TGF-β1 on URG-4/URGCP gene was determined using REAL TIME PCR at mRNA level and Western blotting/immunofluorescence at protein level. Transient transfection assays were carried out to find out which site of promoter is upregulated by TGF-β1.
  
  
  RESULTS
  We report the upregulation of URG-4/URGCP gene expression by TGF-β1 in hepatoma cells along with prostate cancer cells, PC3. Transient transfection assays showed that the -109 to +63 promoter region contained the minimal TGF-β1 response elements. TGF-β1 markedly stimulated the URG-4/URGCP mRNA and protein that was blocked by MEK1 [MAPK (Mitogen-Activated Protein Kinase)/ERK (extracellular signal-regulated kinase) kinase 1] inhibitor, PD98059 and PI3K inhibitor, wortmannin.
  
  
  CONCLUSIONS
  These studies show for the first time that TGF-β1 upregulates the expression of URG-4/URGCP in human hepatocytes and identifies the signaling pathways underlying this response.
authors.affiliation: Department of Molecular Biology and Genetics, Faculty of Science and Literature, Balikesir University, Balikesir, Turkey.
authors.forename: Esra
authors.initials: E
authors.lastname: Tokay
authors.affiliation: Department of Molecular Biology and Genetics, Faculty of Science and Literature, Balikesir University, Balikesir, Turkey. Electronic address: fkockar@balikesir.edu.tr.
authors.forename: Feray
authors.initials: F
authors.lastname: Kockar
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D018450:Disease Progression; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008297:Male; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D014162:Transfection; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D004791:Enzyme Inhibitors; D005419:Flavonoids; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; C470990:URGCP protein, human; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D000077191:Wortmannin
keywords: MAPK/ERK; PI3K; Promoter; TGF-β; URG-4/URGCP; Upregulation