Estrogenic activity assessment of environmental chemicals using in vitro assays: identification of two new estrogenic compounds.
Estrogenic activity assessment of environmental chemicals using in vitro assays: identification of two new estrogenic compounds.
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DOI：
10.1289/ehp.00108621
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发表时间：
2000-07
影响因子：
10.4
通讯作者：
Wahli W
中科院分区：
文献类型：
--
作者：
Lascombe I;Beffa D;Rüegg U;Tarradellas J;Wahli W
具有雌激素活性的环境化学物质已被认为与动物和人类的有害影响有关。为了表征雌激素化学物质及其作用机制，我们建立了体外和细胞培养实验，检测人类雌激素受体[α] （hER[α]）介导的雌激素性。首先，我们分析了化学物质，以确定它们调节hER[α]和类固醇受体共激活因子-1 （SRC-1）之间直接相互作用的能力，并在竞争结合试验中取代17ss-雌二醇（E(2)）。其次，我们在酵母雌激素筛选和雌激素反应的MCF-7人类乳腺癌细胞系中测试了这些化学物质的雌激素相关转录活性。本研究研究的化学物质是o，p'- ddt（外消旋混合物和对映体），壬基苯酚混合物（NPm），以及环境中两种分析较少的化合物，即tris-4-（氯苯基）甲烷（Tris-H）和tris-4-（氯苯基）甲醇（Tris-OH）。在酵母和MCF-7细胞中，我们通过雌激素受体（ER）测定了o，p'-DDT， NPm以及Tris-H和Tris-OH的雌激素活性。然而，与雌激素不同的是，这些外源药物似乎都不能诱导ER/SRC-1相互作用，这很可能是因为被激活受体的构象不允许与这种辅激活因子直接接触。然而，这些化合物能够抑制[(3)H]-E(2)与hER的结合，这揭示了与受体的直接相互作用。综上所述，试验化合物是雌激素模拟物，但受体/辅激活物相互作用分析显示其分子作用机制与天然激素不同。
Environmental chemicals with estrogenic activities have been suggested to be associated with deleterious effects in animals and humans. To characterize estrogenic chemicals and their mechanisms of action, we established in vitro and cell culture assays that detect human estrogen receptor [alpha] (hER[alpha])-mediated estrogenicity. First, we assayed chemicals to determine their ability to modulate direct interaction between the hER[alpha] and the steroid receptor coactivator-1 (SRC-1) and in a competition binding assay to displace 17ss-estradiol (E(2)). Second, we tested the chemicals for estrogen-associated transcriptional activity in the yeast estrogen screen and in the estrogen-responsive MCF-7 human breast cancer cell line. The chemicals investigated in this study were o,p'-DDT (racemic mixture and enantiomers), nonylphenol mixture (NPm), and two poorly analyzed compounds in the environment, namely, tris-4-(chlorophenyl)methane (Tris-H) and tris-4-(chlorophenyl)methanol (Tris-OH). In both yeast and MCF-7 cells, we determined estrogenic activity via the estrogen receptor (ER) for o,p'-DDT, NPm, and for the very first time, Tris-H and Tris-OH. However, unlike estrogens, none of these xenobiotics seemed to be able to induce ER/SRC-1 interactions, most likely because the conformation of the activated receptor would not allow direct contacts with this coactivator. However, these compounds were able to inhibit [(3)H]-E(2) binding to hER, which reveals a direct interaction with the receptor. In conclusion, the test compounds are estrogen mimics, but their molecular mechanism of action appears to be different from that of the natural hormone as revealed by the receptor/coactivator interaction analysis.