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 在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 不太了解。我们克隆了细胞色素P4501 B1（CYP 1B 1），并显示 CYP 1B 1-null小鼠对几种癌症具有抗性，这些癌症是由 正常小鼠体内的多环芳烃。我们将检验CYP 1B 1在细胞内起主要作用的假说， 在PAH诱导的乳腺癌中的作用，并且贡献大于 对于CYP 1A 1，由于以下一个或多个原因：（1）CYP 1B 1是 在乳腺上皮中组成型表达，而CYP 1A 1需要诱导 PAH，通过AhR;（2）CYP 1B 1，也通过AhR， 在多种乳腺细胞类型中表达，包括腔细胞和基底细胞 上皮细胞和高度增殖的祖细胞群， 很容易变形CYP 1A 1主要表达于 （3）多环芳烃优先代谢为 致癌二氢二醇环氧化物（PAHDE）通过CYP 1B 1相对于CYP 1A 1。人类 来自乳房缩小成形术组织的原发性乳房上皮细胞将被解决 转化为不同的细胞类型待检测的多环芳烃为：二苯并[a，l]芘 苯并[a]芘（BP），一种 海湾地区PAH;和7，12-二甲基苯并[a]蒽（DMBA），一种假峡湾PAR。 将在小鼠（野生型）中分析代谢和PAHIDE-DNA加合物形成 和CYP 1B 1-null）与乳腺癌发生的关系 BP、DMBA和diBP暴露。类似的代谢分析将在 用于比较CYP 1B 1和CYP 1A 1的分离的原代人乳腺上皮细胞 表达和AhR激活。CYP 1B 1的作用将进一步定义为 在接近正常的人乳腺中反义抑制或过度表达 上皮细胞系MCF-10 F。这些代谢活化的多环芳烃导致生长 在低浓度下被捕。我们将确定这种反应的标志，我们 将研究CYP 1B 1在PAHDE-DNA加合物形成中的作用。的 将MCF-10 F细胞（包括表达变体）转化为 形式锚定独立殖民地将被用来测试参与 CYP 1B 1在这些变化中的作用，与早期阶段的 致癌作用这项工作将首次检查PAR激活， 良好表征的原代人乳腺细胞被培养以在 体内导管形态学。与CYP 1B 1表达和活性的相关性 将提供深入了解小鼠模型与人类乳房的关系 癌

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.