Selective Induction of Estrogen Conjugative Metabolism

描述(申请人提供)：这项建议旨在测试一项新的假设，即能够优先刺激雌二醇(E2)及其羟化代谢物(如4-OH-E2和16pha-OH-E1)代谢转化为非活性、水溶性的偶联物的化学物质将是比雌激素氧化代谢诱导剂更好和更安全的雌二醇诱导癌抑制剂。根据我们最近关于饮食中的二苯甲酰甲烷(DAM)对人乳腺细胞和动物的E2结合代谢的优先刺激作用的数据，我们提出了以下四个具体目标来初步检验这一新假说。目的：通过生化分析和Northern印迹分析，研究膳食DBM及其类似物在人乳腺非肿瘤细胞AG11134中诱导雌激素结合酶(葡萄糖糖醛酸化、硫酸化和O-甲基化)与氧化的活性。目的2：研究目标1中确定的强饮食诱导剂在雌性ACI大鼠肝脏、乳房和子宫中诱导雌激素结合的活性。目的：比较雌激素结合强诱导剂和典型的饮食雌激素氧化诱导剂吲哚-3-甲醇对雌性ACI大鼠血液和靶器官中雌二醇和4-羟基雌二醇代谢的影响。目的：比较雌激素结合代谢诱导剂和吲哚-3-甲醇对雌性大鼠乳腺和子宫中E_2和4-OH-E_2促有丝分裂作用的影响，比较它们对雌激素诱导的雌性ACI大鼠乳腺肿瘤的预防作用。我们预测，在雌激素的激素活性同样受到抑制的情况下，雌激素结合代谢诱导剂将比雌激素氧化代谢诱导剂具有更高的癌症预防效果。这些假设驱动的、基于机制的研究将导致开发一种有效的、新的策略，用于以饮食或植物化学为基础的预防雌激素诱导的人类癌症。这些研究还将检验生物活性雌激素代谢产物(如4-OH-E2和16α-OH-E2)在雌激素诱导的癌症中的重要作用。

DESCRIPTION (provided by applicant): This proposal is aimed at testing a novel hypothesis that chemicals that can preferentially stimulate the metabolic conversion of estradiol (E2) and its hydroxylated metabolites (such as 4-OH-E2 and 16alpha-OH-E1) to inactive, water-soluble conjugates would be better and safer inhibitors of E2-induced cancer than inducers of estrogen oxidative metabolism. On the basis of our recent data on the preferential stimulatory effect of dietary dibenzoylmethane (DAM) on E2 conjugative metabolism in human mammary cells and in animals, we propose the following four Specific Aims for our initial testing of this novel hypothesis. Aim 1: To study dietary DBM and its analogs for their activity in inducing the enzymes for estrogen conjugation (glucuronidation, sulfation, and O-methylation) vs oxidation in non-neoplastic AG11134 human mammary epithelial cells by using biochemical assays and Northern blot analysis. Aim 2: To study strong dietary inducers identified under Aim 1 for their activity in inducing estrogen conjugation in liver, breast, and uterus of female ACI rats. Aim 3: To compare the effects of strong inducers of estrogen conjugation with indole-3-carbinol (a prototypical dietary inducer of estrogen oxidation) on the metabolic fate of E2 and 4-OH-E2 (a representative bioactive hydroxyestrogen metabolite) in blood and target organs of female ACI rats. Aim 4: To compare the effects of an identified inducer of estrogen conjugative metabolism with indole-3-carbinol on the mitogenic actions of E2 and 4-OH-E2 in the breast and uterus of female rats, and to compare their efficacies in the prevention of estrogen-induced mammary tumors in female ACI rats. We predict that an inducer of estrogen conjugative metabolism will have a much higher cancer-preventive efficacy than an inducer of estrogen oxidative metabolism under conditions where estrogen's hormonal activity is equally inhibited. These hypothesis-driven, mechanism-based studies will lead to the development of an effective, novel strategy for dietary or phytochemical-based prevention of estrogen-induced human cancers. These studies will also provide examinations of the important roles of bioactive estrogen metabolites (e.g., 4-OH-E2 and 16alpha-OH-E2) in estrogen-induced cancers.