Development in a dish: an ex-vivo fetal mammary assay for toxicological research

摘要 超过8万种化学品在美国注册用于商业用途，其中许多 是内分泌干扰物，并对人类健康构成重大风险，因此需要 对其发育毒性的有效评估。胎儿器官发生是一个时期 增加对毒物的易感性，特别是对那些干扰激素的毒物 行动。胎儿乳腺被认为特别容易受到荷尔蒙的影响。 乳房破裂；暴露于异种雌激素，如己烯雌酚(DES)可增加乳房 女性的癌症发病率。尽管有这一发现，但没有数据报告 胎儿MG发育过程中的DES(将在S.Aim 1中进行检查)。同样，胎儿 暴露于双酚A(BPA)及其替代物导致Pre-Pre 在出生后很久才表现出来的肿瘤和肿瘤性病变 暴露(对胎儿MG发育的影响将在S.Aim 2中进行研究)。 目前还没有可重现的系统来允许直接观察 激素和内分泌干扰物对乳腺发育的影响 绕过内源性激素的作用和雌激素的捕获作用 甲胎蛋白(AFP)。使用一种体外培养试验，在这种试验中，乳芽 在体外完成胎儿形态发生，使我们能够实时观察这一过程。 体外方法的验证需要比较选定的化学物质的效果 在体外和体内检测中不与甲胎蛋白结合。在这方面，我们观察到 一种不与甲胎蛋白结合的类固醇雌激素--乙炔雌二醇抑制导管 在体外和体内都有生长。相反，低浓度的双酚A增加了导管 在体内和在这种体外培养方法中都有发展。 目的1：研究DES对胎儿乳腺的体内外作用 发展。目的2：比较鸡传染性支气管炎引起的体内外胎儿MG的表型。 暴露于已知可导致增殖性病变和/或癌症的内分泌干扰物 啮齿动物。我们将使用BPA替代品BPS和BPAF。一种有效的体外培养方法 对发育中的MG的检测将极大地促进机制和形态计量研究 并为毒理学家提供了一种可靠、快速的方法 测试化学物质的潜在发育毒性。

Summary More than 80,000 chemicals are registered for commercial use in the U.S. Many of them are endocrine disruptors and pose major risks to human health, hence the need for efficient evaluation of their developmental toxicity. Fetal organogenesis is a period of increased vulnerability to toxicants, in particular to those that interfere with hormone action. The fetal mammary gland is considered particularly vulnerable to hormonal disruption; exposure to xenoestrogens like diethylstilbestrol (DES) increased breast cancer incidence in women. Despite this finding, there is no data reporting the effects of DES during fetal MG development (to be examined in S. Aim 1). Likewise, fetal exposure to bisphenol A (BPA) and its replacements led to the development of pre- neoplastic and neoplastic lesions that manifested postnatally, long after the end of exposure (effect on fetal MG development will be examined in S. Aim 2). There is currently no reproducible system that allows for the observation of the direct effects of hormones and endocrine disruptors on the developing mammary gland while bypassing the effect of endogenous hormones and the estrogen-trapping effect of alphafetoprotein (AFP). Using an ex-vivo culture assay in which the mammary bud completes fetal morphogenesis in-vitro, allowed us to observe this process in real time. Validation of the ex-vivo method requires comparing the effects of selected chemicals that do not bind to AFP in the ex-vivo and in-vivo assays. In this regard, we observed that ethinyl estradiol, a steroidal estrogen that does not bind to AFP inhibited ductal growth both ex-vivo and in-vivo. In contrast, low BPA concentrations increased ductal development both in-vivo and in this ex-vivo explant method. Aim 1: To examine the ex-vivo and in-vivo effects of DES on fetal mammary gland development. Aim 2: To compare the ex-vivo and in-vivo fetal MG phenotype caused by exposure to endocrine disruptors known to induce proliferative lesions and/or cancer in rodents. We will use the BPA replacements BPS and BPAF. A validated ex-vivo culture assay of the developing MG will greatly facilitate mechanistic and morphometric studies of mammary gland development and provide toxicologists with a reliable, faster method to test chemicals for potential developmental toxicity.