Mechanisms of Tumor Promotion Effects of B[a]PDE

B[a]PDE的促癌作用机制

• 批准号: 7072773
• 负责人: CHUANSHU HUANG
• 金额: $ 35.27万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7072773
• 关键词: AP1 protein; JUN kinase; benzopyrenediol epoxide; biological signal transduction; carbopolycyclic compound; chemical carcinogenesis; chemical related neoplasm /cancer; electron spin resonance spectroscopy; gel mobility shift assay; gene induction /repression; genetically modified animals; immunocytochemistry; laboratory mouse; luciferin monooxygenase; pathologic process; phosphatidylinositol 3 kinase; tissue /cell culture; tobacco

DESCRIPTION (provided by applicant): Polycyclic aromatic hydrocarbons (PAHs), such as benzo[a]pyrene (B[a]P), are ubiquitous complete carcinogens that are present in tobacco smoke. The majority of work in previous studies has focused on the mutations that are associated with the tumor initiation effect of these compounds. However, the tumor promotion effect of PAHs, which is thought to be mediated through regulation of signal transduction pathways leading to activation of transcription factors, remains unclear. Our preliminary studies suggest that benzo[a]pyrene diol-epoxide (B[a]PDE), an ultimate carcinogenic metabolite of benzo[a]pyrene (B[a]P), is a major compound responsible for activation of the transcription factor activator protein-1 (AP-1) in non-cytotoxic concentrations. Since growing evidence has shown that activation of AP-1 by carcinogens is required for tumor promotion in both cell culture models and animal experiments, the main hypothesis of this proposal is that signal transduction pathways leading to activation of AP-1 play a critical role in the tumor promotion effect induced by B[a]PDE. The overall aim of this proposal is to elucidate the molecular mechanisms by which PAHs induce tumor promotion. Especially, we will establish the signal transduction pathways leading to AP-1 activation by B[a]PDE in a well-characterized tumor promotion cell culture model, mouse epidermal C141 cells. We will then investigate whether the same pathway occurs in an in vivo model using an AP-1-luciferase reporter transgenic mouse model. Furthermore, we will determine the role of AP-1 activation in B[a]PDE-induced tumor promotion in a two-stage carcinogenesis mouse skin model using dominant negative mutant c-jun (TAM67) transgenic mice. We will investigate these issues in accordance with the following testable hypotheses and specific aims: 1) To elucidate early events involved in initiating the signaling pathways leading to AP-1 activation by B[a]PDE in mouse epidermal C141 cells; 2) To test the hypothesis that the PI-3K/Akt/p7086k pathway is required for B[a]PDE-induced AP-1 activation in mouse epidermal C141 cells; 3) To determine whether B[a]PDE is able to induce AP-1 activation in vivo by using AP-1-luciferase reporter transgenic mice and whether this activation is through the same signal transduction pathways as in vitro; 4) To test the hypothesis that AP-1 activation is essential in the tumor promotion effect of B[a]PDE in a two-stage carcinogenesis mouse model. The significance of the research proposed in this application is that the results derived from the proposed studies will greatly facilitate the understanding of the molecular mechanism of cancer development caused by B[a]P and B[a]PDE. A better understanding of signal transduction pathways leading to AP-1 induction may provide valuable information needed for designing more effective agents for prevention and therapy of cancers caused by cigarette smoke. Such agents could interfere with the signaling pathways leading to AP-1 activation.

描述（由申请人提供）：多环芳烃（PAH），例如苯并[a]芘（B[a]P），是烟草烟雾中普遍存在的完全致癌物。先前研究的大部分工作都集中在与这些化合物的肿瘤引发作用相关的突变上。然而，PAHs 的肿瘤促进作用被认为是通过调节信号转导途径导致转录因子激活来介导的，但目前尚不清楚。我们的初步研究表明，苯并[a]芘二醇环氧化物（B[a]PDE）是苯并[a]芘（B[a]P）的最终致癌代谢物，是负责激活转录因子的主要化合物非细胞毒性浓度的激活蛋白-1 (AP-1)。由于越来越多的证据表明，在细胞培养模型和动物实验中，致癌物激活 AP-1 是促进肿瘤生长所必需的，因此该提议的主要假设是，导致 AP-1 激活的信号转导途径在肿瘤生长过程中发挥着关键作用。 B[a]PDE 诱导的肿瘤促进作用。该提案的总体目标是阐明多环芳烃诱导肿瘤生长的分子机制。特别是，我们将在充分表征的肿瘤促进细胞培养模型（小鼠表皮 C141 细胞）中建立导致 B[a]PDE 激活 AP-1 的信号转导途径。然后，我们将使用 AP-1-荧光素酶报告基因转基因小鼠模型研究相同的途径是否发生在体内模型中。此外，我们将使用显性失活突变体 c-jun (TAM67) 转基因小鼠，在两阶段致癌小鼠皮肤模型中确定 AP-1 激活在 B[a]PDE 诱导的肿瘤促进中的作用。我们将根据以下可检验的假设和具体目标来研究这些问题： 1) 阐明小鼠表皮 C141 细胞中参与 B[a]PDE 激活 AP-1 信号通路的早期事件； 2) 检验 B[a]PDE 诱导小鼠表皮 C141 细胞中 AP-1 激活需要 PI-3K/Akt/p7086k 通路的假设； 3) 利用AP-1-荧光素酶报告基因转基因小鼠，确定B[a]PDE是否能够在体内诱导AP-1激活，以及这种激活是否通过与体外相同的信号转导途径； 4) 在两阶段致癌小鼠模型中检验 AP-1 激活对于 B[a]PDE 的肿瘤促进作用至关重要的假设。本申请提出的研究的意义在于，所提出的研究的结果将极大地促进对B[a]P和B[a]PDE引起的癌症发展的分子机制的理解。更好地了解导致 AP-1 诱导的信号转导途径可能会为设计更有效的药物来预防和治疗由香烟烟雾引起的癌症提供所需的有价值的信息。此类药物可能会干扰导致 AP-1 激活的信号通路。