2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces plasminogen activator inhibitor-1 through an aryl hydrocarbon receptor-mediated pathway in mouse hepatoma cell lines.
2,3,7,8-Tetrachlorodibenzo- p-dioxin (TCDD), a ubiquitous environmental pollutant, elicits a variety of toxicities and is a well-known carcinogen. TCDD alters the expression of many genes including CYP1A1/2, CYP1B1, glutathione S-transferase Ya, aldehyde-3-dehydrogenase, NAD(P)H:quinone oxidoreductase, transforming growth factor (TGF)-alpha and TGF-beta. The present study was aimed at characterization of TCDD to induce plasminogen activator inhibitor-1 (PAI-1) in mouse hepatoma cell lines. A Hepa1c1c7 wild-type cell [H1(wt)], an aryl hydrocarbon receptor (AhR)-deficient mutant [H1(AhR(-))] and an AhR nuclear translocator (Arnt)-deficient mutant [H1(Arnt(-))] were used for this study. TCDD induced PAI-1 in H1(wt) cells, but not in H1(AhR(-)) and H1(Arnt(-)) mutants, indicating a functional role of the AhR-Arnt complex in this effect. Cycloheximide (CHX) treatment resulted in increased PAI-1 mRNA induction, indicating that this response to TCDD is a direct effect on transcription and not a secondary effect mediated by other TCDD-induced proteins. Transfection with PAI-1 promoter led to increased PAI-1 promoter activity in H1(wt) cells treated with TCDD, but no such effect occurred in H1(AhR(-)) or H1(Arnt(-)) cells, implying involvement of the AhR and Arnt. In addition, alpha-naphthoflavone and phenanthroline, two AhR antagonists, each blocked the enhancing effect of TCDD on PAI-1 promoter-coupled luciferase activity in H1(wt) cells. PAI-1 promoter deletion analysis indicated that TCDD-induced PAI-1 transcription was distinctly different from TGF-beta-dependent PAI-1 transcription, particularly in the region between -161 to +73. In summary, TCDD induced the PAI-1 gene directly via an AhR- and Arnt-dependent mechanism, which was distinctly different from TGF-beta-driven PAI-1 transcription.
Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA.
Deok-Soo
DS
Son
Karl K
KK
Rozman
D000818:Animals; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator; D015152:Blotting, Northern; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000633:toxicity*; D051379:Mice; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis*; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis; D018336:Receptors, Aryl Hydrocarbon / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics; D014407:Tumor Cells, Cultured
C497397:Arnt protein, mouse; D004268:DNA-Binding Proteins; D004785:Environmental Pollutants; D017395:Plasminogen Activator Inhibitor 1; D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D051784:Aryl Hydrocarbon Receptor Nuclear Translocator