Polycyclic Hydrocarbons and CYP1B1 in Breast Cancer

描述：(改编自申请人的摘要)：许多多环芳烃是有效的 啮齿动物模型中的乳腺癌致癌物，但它们在人类乳腺癌中的作用是 人们对此知之甚少。我们克隆了细胞色素P4501B1(CyP1B1)，并展示了 CYP1B1缺失的小鼠对几种癌症具有抵抗力，这些癌症是由 正常小鼠体内的多环芳烃。我们将检验这一假设，即细胞色素P1B1是主要的 在多环芳烃诱导的乳腺癌中的作用，并且其贡献大于 由于以下一个或多个原因：(1) 在乳腺上皮细胞中组成性表达，而CYP1A1需要诱导 通过PAH，通过AH受体(AhR)；(2)也通过AhR的CYP1B1， 在多种类型的乳腺细胞中表达，包括腔细胞和基底细胞 上皮细胞和高增殖的前体细胞群可能是 非常容易变形的。CYP1A1主要在更多的 分化的腔上皮；(3)多环芳烃优先代谢为 致癌的二氢二醇环氧化物(PAHDE)由CYP1B1相对于CYP1A1。人类 乳房缩小整形组织的原代乳房上皮将被解决 转化为各自的细胞类型。待检测的多环芳烃为：二苯并[a，L]芘 (DIBP)，代表最有效的峡湾类；苯并[a]芘(BP)，a 湾区多环芳烃和7，12-二甲基苯并[a]菲(DMBA)，一种拟峡湾PAR。 将分析小鼠(野生型)的代谢和PAHIDE-DNA加合物的形成 和CYP1B1-空)在体内与下列乳腺癌的发生有关 BP、DMBA和DIBP暴露。类似的代谢分析将于#年完成。 分离的原代人乳腺上皮细胞色素P4501B1和细胞色素P1A1的比较 表达和AhR激活。CYP1B 1的作用将进一步定义为 在接近正常的人乳房中反义抑制或过度表达 上皮细胞系MCF-10F。这些新陈代谢激活的多环芳烃会导致生长 在低浓度下被逮捕。我们将确定这种反应的标志，我们 将研究CYP1B1在PAHDE-DNA加合物形成中的作用。这个 MCF-10F细胞(包括表达变异体)转化为 形式锚定独立的殖民地将被用来测试参与 细胞色素P1B1在这些变化中，这与早期阶段相关 致癌。这项工作将在年首次研究PAR激活 具有良好特性的原代人类乳房细胞，培养后在 活体导管形态。细胞色素P1B_1表达与活性的相关性 将深入了解小鼠模型与人类乳房的关系 癌症。

DESCRIPTION: (Adapted from the Applicant's Abstract): Many PAHs are potent mammary carcinogens in rodent models, but their role in human breast cancer is poorly understood. We have cloned cytochrome P4501B1 (CYP1B1) and have shown that CYP1B 1-null mice are resistant to several cancers, which are induced by PAHs in normal mice. We will test the hypothesis that CYP1B 1 plays a major role in PAH-induced breast cancer, and that the contribution is greater than for CYP1A1 for one or more of the following reasons: (1) CYP1B1 is constitutively expressed in breast epithelia, whereas CYP1A1 requires induction by the PAH, via the Ah-receptor (AhR); (2) CYP1B1, which is also via the AhR, is expressed in multiple breast cell types, including luminal and basal epithelia and a highly proliferative progenitor cell population that may be very susceptible to transformation. CYP1A1 is primarily expressed in more differentiated luminal epithelia; (3) PAHs are preferentially metabolized to carcinogenic dihydrodiol epoxides (PAHDE) by CYP1B1 relative to CYP1A1. Human primary breast epithelia from reduction mammoplasty tissues will be resolved into the respective cell types. The PAHs to be examined are: dibenzo[a,l]pyrene (diBP), representative of the most potent fjord class; benzo[a]pyrene (BP), a bay-region PAH; and 7,12-dimethylbenz[a]anthracene (DMBA), a pseudo-fjord PAR. Metabolism and PAHIDE-DNA adduct formation will be analyzed in mice (wild type and CYP1B 1-null) in vivo in relation to mammary cancer development following BP, DMBA, and diBP exposure. Similar metabolic analyses will be completed in separated primary human breast epithelia for comparison of CYP1B1 and CYP1A1 expression and AhR activation. The role of CYP1B 1 will be further defined by anti-sense suppression or over-expression in the near normal human breast epithelial cell line, MCF-10F. These metabolically activated PAHs cause growth arrest at low concentrations. We will identify markers of this response, and we will examine the role of CYP1B1 in PAHDE-DNA adduct formation. The transformation of MCF-10F cells (including expression variants) to cells that form anchorage-independent colonies will be used to test the involvement of CYP1B 1 in these changes, which correlate with the early stages of carcinogenesis. This work will examine PAR activation for the first time in well characterized primary human breast cells that are cultured to replicate in vivo ductal morphology. The correlation with CYP1B 1 expression and activity will provide insight into the relationship of the mouse model to human breast cancer.