Differential action of polycyclic aromatic hydrocarbons on endogenous estrogen-responsive genes and on a transfected estrogen-responsive reporter in MCF-7 cells
Differential action of polycyclic aromatic hydrocarbons on endogenous estrogen-responsive genes and on a transfected estrogen-responsive reporter in MCF-7 cells
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DOI：
10.1016/j.taap.2003.12.003
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发表时间：
2004-04-01
影响因子：
3.8
通讯作者：
Arcaro, KF
中科院分区：
文献类型：
--
作者：
Gozgit, JM;Nestor, KM;Arcaro, KF
多环芳烃（PAHs）是常见的环境污染物，已被广泛研究的多个毒理学终点在实验室动物和人类。本研究旨在探讨多环芳烃对人乳腺癌细胞MCF-7的雌激素样作用。我们研究了14种多环芳烃结合雌激素受体（ER）或芳烃受体（AhR）和激活靶基因表达的能力。多环芳烃进行了测试，在人类重组雌激素受体（hrER）的竞争性结合试验，并在雌激素反应元件（ERE）和异生素反应元件（XRE）介导的报告基因测定。我们使用定量RT-PCR来检查选定的多环芳烃，其在ERE报告基因测定中显示活性，以上调雌激素响应基因HEM 45、孕酮受体和pS2以及芳香烃响应CYP 1A 1基因的能力。14种多环芳烃均不与hrER结合，但其中5种多环芳烃（蒽、B[a]A、金、B[B]F和B[a]P）诱导ER报告活性。这种活性依赖于MCF-7细胞中多环芳烃通过AhR途径的代谢，这导致形成结合ER的代谢产物。没有五个多环芳烃，诱导ER-报告被发现上调雌激素反应基因，但五个多环芳烃诱导AhR依赖的CYP 1A 1基因表达。相反，B[a]P的代谢物3 'OH-B [a]P和PCB代谢物4' OH-2，4，6-BP对所有三种雌激素应答基因都有微弱的上调作用。来自这些研究的数据表明，单独诱导ER-报告基因活性不一定与内源性基因转录平行，并且报告基因测定法可以检测在体内不起作用的相互作用。(C)2004年爱思唯尔公司All rights reserved.
Polycyclic aromatic hydrocarbons (PAHs) are common environmental pollutants that have been extensively studied for multiple toxicological endpoints in both laboratory animals and humans. The purpose of this study was to investigate the estrogenicity of PAHs in the human breast cancer cell line MCF-7. We investigated 14 PAHs for their ability to bind either the estrogen receptor (ER) or the aryl hydrocarbon receptor (AhR) and to activate target gene expression. PAHs were tested in a human recombinant estrogen receptor (hrER) competitive binding assay, and in both an estrogen response element (ERE)- and xenobiotic response element (XRE)-mediated reporter gene assay. We used quantitative RT-PCR to examine selected PAHs that showed activity in the ERE reporter gene assay for their ability to upregulate estrogen-responsive genes HEM45, progesterone receptor, and pS2, and the aryl hydrocarbon-responsive CYP1A1 gene. None of the 14 PAHs bound the hrER, but five of the PAHs (anthracene, B[a]A, chrysene, B[b]F, and B[a]P) induced ER-reporter activity. This activity was dependent on the metabolism of PAHs in MCF-7 cells via the AhR pathway, which resulted in the formation of metabolites that bound the ER. None of the five PAHs that induced the ER-reporter were found to upregulate estrogen-responsive genes, yet four of the five PAHs induced AhR-dependent CYP1A1 gene expression. In contrast, a metabolite of B[a]P, 3'OH-B[a]P, and a PCB metabolite, 4'OH-2,4,6-BP, did weakly upregulate all three estrogen-responsive genes. Data from these studies indicate that induction of ER-reporter activity alone does not necessarily parallel endogenous gene transcription, and that the reporter gene assay may detect interactions that are not functional in vivo. (C) 2004 Elsevier Inc. All rights reserved.