Circadian regulation of PAH metabolism

 描述(申请人提供)：生物钟在协调从行为到细胞新陈代谢和有丝分裂的许多生物过程中起着关键作用。最近的研究表明，昼夜节律的紊乱与乳腺癌风险的增加有关，这表明轮班工作的女性患乳腺癌的风险可能更高。我们最近的结果表明，分子计时的中断对决定多芳烃(PAH)代谢结果的几个过程产生了负面影响，导致DNA损伤增加。我们发现，在小鼠乳腺和乳腺癌细胞系中，一天中的时间以及单个生物钟成分独特地调控苯并[a-芘](BaP)激活的芳香烃受体(AHR)和雌激素受体(ER)介导的内分泌干扰物(EDC)信号转导过程。这一新的认识使我们假设生物钟影响BaP介导的新陈代谢和DNA损伤和修复，而一天中的时间或生物钟的中断影响PAH暴露和EDC活性的结果。为了检验这一假设，我们提出了两个具体目标。在目标1中，我们将通过分析BaP诱导的AHR和ER信号的差异，BaP-DNA加合物和DNA损伤反应的形成和持续，以及BaP清除的时间过程，来定义小鼠乳腺组织和MCF7乳腺癌细胞的昼夜“敏感性窗口”，利用一种新的多光子成像方法来实时测量体内外BaP代谢的昼夜相关性差异。在目标2中，我们将利用一种新的乳腺移植方法，首次在活体内识别中枢和外周影响，通过昼夜节律和AHR和Era基因敲除小鼠模型，以及体内AHR和ER结合的芯片-序列分析，在乳腺组织中识别Circadia时钟对BaP急性毒性和雌激素作用的影响。这项研究的预期结果将是确定多环芳烃在促进DNA损伤和乳腺癌方面与生物钟相互作用的关键作用部位和代谢途径。

 DESCRIPTION (provided by applicant): The circadian clock plays a key role in coordinating many biological processes from behaviors to cellular metabolism and mitosis. Recent studies have linked disruption of circadian rhythms with increased breast cancer risk, suggesting women working alternative shifts may have a higher risk of breast cancer. Our recent results indicate that disruption of molecular timing negatively impacts several processes that determine the outcome of polyaromatic hydrocarbon (PAH) metabolism, resulting in increased DNA damage. We have found that time of day, as well as individual circadian clock components, uniquely regulate processes governing benzo-a-pyrene (BaP) activated aryl hydrocarbon receptor (AHR) and estrogen receptor (ER) mediated endocrine disruptor (EDC) signaling in the mouse mammary gland and breast cancer cell lines. This new knowledge led us to hypothesize that the circadian clock influences BaP-mediated metabolism and DNA damage and repair, and that time of day, or disruption of the circadian clock, impacts the outcome of PAH exposure and EDC activity. To test this hypothesis we propose two Specific Aims. In Aim 1, we will define the circadian "windows of susceptibility" in mouse mammary tissues and MCF7 breast cancer cells by analyzing differences in BaP-induced AHR- and ER- signaling, formation and persistence of BaP-DNA adducts and DNA damage responses and the time course of BaP clearance using a novel multiphoton imaging approach to measure real time circadian-dependent differences in BaP metabolism in vitro and in vivo. In Aim 2, we will utilize a novel mammary gland transplant approach to discern for the first time in vivo central versus peripheral affects mediating circadia clock influences on acute BaP-induced toxicity and estrogen action in mammary tissues using circadian and AHR and ERa knockout mouse models and binding of AHR and ER in vivo by ChIP-Seq analysis. The expected outcomes of this research will be identification of the key sites of action and metabolic pathways by which PAHs interact with circadian clocks in promoting DNA damage and breast cancer.