Aarts J M, Denison M S, Cox M A, Schalk M A, Garrison P M, Tullis K, de Haan L H, Brouwer A
Department of Toxicology, Agricultural University, Wageningen, Netherlands.
Eur J Pharmacol. 1995 Dec 7;293(4):463-74. doi: 10.1016/0926-6917(95)90067-5.
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.
利用显示荧光素酶报告基因受芳烃受体（Ah受体）控制表达的重组细胞系，研究了二邻位取代多氯联苯（PCBs）与Ah受体激动剂的相互作用。在重组的Hepa1c1c7小鼠肝癌（H1L1.1c7）细胞中，观察到2,2',5,5'-四氯联苯（PCB52）与2,3,7,8-四氯二苯并-p-二恶英（TCDD）或3,3',4,4'-四氯联苯（PCB77）诱导的荧光素酶表达之间存在强烈的拮抗相互作用，同样，2,2',3,3',4,4'-六氯联苯（PCB128）与PCB77之间也存在这种相互作用。因此，发现PCB52在野生型Hepa1c1c7细胞中可抑制PCB77诱导的乙氧基异吩恶唑酮-O-脱乙基酶（EROD）活性。相反，PCB52对TCDD诱导的荧光素酶表达的拮抗作用在重组豚鼠GPC16结肠腺癌（G16L1.1c8）细胞和人HepG2肝癌（HG2L1.1c3）细胞中较小，在重组H4IIE大鼠肝癌（H4L1.1c4）细胞中处于中等水平。使用含32P标记的二恶英反应元件（DRE）的寡核苷酸进行凝胶阻滞研究，以及使用[3H]TCDD进行配体结合研究，结果表明PCB52对Ah受体控制的荧光素酶表达具有物种特异性拮抗活性，这是由于其抑制了Ah受体与配体及DNA的结合。我们得出结论，Ah介导的荧光素酶表达为研究Ah受体（抗）激动剂的物种特异性提供了一个有用的工具。
