title: Species-specific antagonism of Ah receptor action by 2,2',5,5'-tetrachloro- and 2,2',3,3'4,4'-hexachlorobiphenyl.
abstract: Using recombinant cell lines showing Ah receptor-controlled expression of a luciferase reporter gene, the interaction of di-ortho-substitute polychlorinated biphenyls (PCBs) with Ah receptor agonists was studied. In the recombinant Hepa1c1c7 mouse hepatoma (H1L1.1c7) cells strong antagonistic interaction of 2,2',5,5'-tetrachlorobiphenyl (PCB52) with luciferase expression induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or 3,3',4,4'-tetrachlorobiphenyl (PCB77) was observed, and similarly, between 2,2',3,3',4,4'-hexachlorobiphenyl (PCB128) and PCB77. Accordingly, PCB52 was found to inhibit ethoxyresorufin-O-deethylase (EROD) induction by PCB77 in wild-type Hepa1c1c7 cells. In contrast, the antagonistic effect of PCB52 on TCDD-induced luciferase expression was only minor in recombinant guinea pig GPC16 colon adenocarcinoma (G16L1.1c8) and human HepG2 hepatoma (HG2L1.1c3) cells, and intermediate in recombinant H4IIE rat hepatoma (H4L1.1c4) cells. Gel retardation studies using a 32 P-labelled dioxin responsive element (DRE)-containing oligonucleotide, and ligand binding studies using [3H]TCDD, demonstrated that the species-specific antagonistic activity of PCB52 on Ah receptor-controlled luciferase expression is due to inhibition of Ah receptor ligand and DNA binding. We conclude, that Ah-mediated luciferase expression provides a useful tool to study the species specificity of Ah receptor (ant)agonists.
authors: Department of Toxicology, Agricultural University, Wageningen, Netherlands.
authors: J M
authors: JM
authors: Aarts
authors: M S
authors: MS
authors: Denison
authors: M A
authors: MA
authors: Cox
authors: M A
authors: MA
authors: Schalk
authors: P M
authors: PM
authors: Garrison
authors: K
authors: K
authors: Tullis
authors: L H
authors: LH
authors: de Haan
authors: A
authors: A
authors: Brouwer
mesh_terms: D000818:Animals; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular; D019363:Cytochrome P-450 CYP1A1; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis; D004790:Enzyme Induction; D006168:Guinea Pigs; D006801:Humans; D008156:Luciferases / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000096:biosynthesis; D011078:Polychlorinated Biphenyls / Q000494:pharmacology*; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018336:Receptors, Aryl Hydrocarbon / Q000037:antagonists & inhibitors*; D014407:Tumor Cells, Cultured
chemical_list: D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; C009407:2,5,2',5'-tetrachlorobiphenyl; D003577:Cytochrome P-450 Enzyme System; D011078:Polychlorinated Biphenyls; D010088:Oxidoreductases; D008156:Luciferases; D019363:Cytochrome P-450 CYP1A1; C014218:2,3,4,2',3',4'-hexachlorobiphenyl; C028451:3,4,3',4'-tetrachlorobiphenyl