Centre for Toxicology, School of Pharmacy, University of London, 29-39 Brunswick Square, London, WC1N 1AX, UK.
Toxicol Appl Pharmacol. 2010 Jun 1;245(2):160-70. doi: 10.1016/j.taap.2010.02.015. Epub 2010 Mar 4.
Estrogen receptor (ER) transcriptional cross-talk after activation by 17beta-estradiol (E2) has been studied in considerable detail, but comparatively little is known about the ways in which synthetic estrogen-like chemicals, so-called xenoestrogens, interfere with these signalling pathways. E2 can stimulate rapid, non-genomic signalling events, such as activation of the Src/Ras/Erk signalling pathway. We investigated how activation of this pathway by E2, the estrogenic environmental contaminants o,p'-DDT, beta-HCH and p,p'-DDE, and epidermal growth factor (EGF) influences the expression of ER target genes, such as TFF1, ER, PR, BRCA1 and CCND1, and the proliferation of breast cancer cells. Despite commonalities in their estrogenicity as judged by cell proliferation assays, the environmental contaminants exhibited striking differences in their non-genomic and genomic signalling. The gene expression profiles of o,p'-DDT and beta-HCH resembled the effects observed with E2. In the case of beta-HCH this is surprising, considering its reported lack of affinity to the "classical" ER. The expression profiles seen with p,p'-DDE showed some similarities with E2, but overall, p,p'-DDE was a fairly weak transcriptional inducer of TFF1, ER, PR, BRCA1 and CCND1. We observed distinct differences in the non-genomic signalling of the tested compounds. p,p'-DDE was unable to stimulate Src and Erk1/Erk2 activations. The effects of E2 on Src and Erk1/Erk2 phosphorylation were transient and weak when compared to EGF, but beta-HCH induced strong and sustained activation of all tested kinases. Transcription of TFF1, ER, PR and BRCA1 by E2, o,p'-DDT and beta-HCH could be suppressed partially by inhibiting the Src/Ras/Erk pathway with PD 98059. However, this was not seen with p,p'-DDE. Our investigations show that the cellular activities of estrogens and xenoestrogens are the result of a combination of extranuclear (non-genomic) and nuclear (genomic) events and highlight the need to take non-genomic effects and signalling cross-talk into consideration, when screening for environmental estrogens. Otherwise, chemicals devoid of ER affinity, such as beta-HCH, but with an effect profile otherwise similar to estrogens might be overlooked in safety testing.
雌激素受体（ER）转录交叉对话后激活 17β-雌二醇（E2）已经进行了相当详细的研究，但比较少的是已知的方式合成雌激素样化学物质，所谓的 xenoestrogens，干扰这些信号通路。E2 可以刺激快速、非基因组信号事件，如激活Src/Ras/Erk 信号通路。我们研究了如何激活这条途径的 E2，雌激素环境污染物 o，p'-DDT，β-六氯环己烷和 p，p'-DDE，表皮生长因子（EGF）的影响表达的 ER 靶基因，如 TFF1，ER，孕激素受体，BRCA1 和 CCND1，和乳腺癌细胞的增殖。尽管有共性在他们的雌激素作为判断通过细胞增殖试验，环境污染物表现出惊人的差异在他们的非基因组和基因组信号。基因表达谱的 o，p'-DDT 和β-六氯环己烷类似于与 E2 观察到的效果。在β-六氯环己烷的情况下这是令人惊讶的，考虑到它的报告缺乏亲和力的“经典”ER。表达谱的 p，p'-DDE 与 E2 有一些相似之处，但总体而言，p，p'-DDE 是一个相当弱的转录诱导 TFF1，ER，孕激素受体，BRCA1 和 CCND1。我们观察到不同的差异在非基因组信号的测试化合物。p，p'-DDE 不能刺激Src 和 Erk1/Erk2 的激活。E2 对 Src 和 Erk1/Erk2 磷酸化的影响是短暂的和微弱的，当与 EGF 相比，但β-六氯环己烷诱导强烈和持续的激活所有测试激酶。转录 TFF1，ER，孕激素受体和 BRCA1 由 E2，o，p'-DDT 和β-六氯环己烷可以被部分抑制通过抑制 Src/Ras/Erk 途径与 PD 98059。然而，这并没有看到与 p，p'-DDE。我们的研究表明，雌激素和 xenoestrogens 的细胞活性是核外（非基因组）和核（基因组）事件的组合的结果，并强调需要考虑非基因组效应和信号交叉对话，在筛选环境雌激素。否则，化学物质缺乏 ER 亲和力，如β-六氯环己烷，但与雌激素的效果谱类似可能会被忽视在安全测试。
