Antagonism of the Ah Receptor in Controlling Breast Cancer Growth and Invasion

Ah 受体在控制乳腺癌生长和侵袭中的拮抗作用

• 批准号: 7738794
• 负责人: Jennifer J Schlezinger
• 金额: $ 21.45万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7738794
• 关键词: Agonist; Aryl Hydrocarbon Receptor; Behavior; Binding; Biological; Biological Factors; Biological Markers; Breast; Breast Cancer Cell; Breast Cancer Model; Breast Cancer Prevention; Breast Cancer Treatment; CYP1B1 gene; Cancer Cell Growth; Cancer Etiology; Carcinogens; Cell Proliferation; Cell model; Cells; Chemicals; Cytochrome P450; DNA; Development; Down-Regulation; Enzymes; Epithelial Cells; Estrogen receptor negative; Exhibits; Exposure to; Flavonoids; Foundations; Gene Expression; Gene Targeting; Genes; Glucosinolates; Growth; Human; In Vitro; Individual; Knock-out; Libraries; Ligands; Malignant - descriptor; Malignant Epithelial Cell; Mammary Neoplasms; Marines; Mediating; Molecular; Morphology; Mus; Mutagenesis; Mutagens; Neoplasm Metastasis; Nuclear; Outcome; Phenotype; Physiological; Plants; Play; Prevention; Proteins; Rattus; Receptor Activation; Resveratrol; Role; Screening procedure; Signal Pathway; Source; Testing; Therapeutic; Therapeutic Agents; Transactivation; Transcriptional Regulation; Translating; Treatment Efficacy; Tumor Cell Invasion; Tumor Cell Line; base; cell growth; cell motility; combinatorial; environmental chemical; high throughput screening; improved; in vivo; malignant breast neoplasm; marine natural product; novel; overexpression; preclinical study; prevent; promoter; public health relevance; receptor; receptor binding; receptor expression; receptor function; repository; slug; tumor; tumor growth; tumor progression

DESCRIPTION (provided by applicant): Historically, the aryl hydrocarbon receptor (AhR) has been studied for its transcriptional regulation of genes encoding cytochrome P450 enzymes, which metabolize environmental and endogenous substrates into toxic and mutagenic intermediates. Accumulating studies support the hypothesis that the AhR also plays an important role in malignant epithelial cell growth and invasion apart from its role in formation of mutagens and in the absence of environmental chemicals. This new paradigm is based on several key observations: 1) AhR expression is increased dramatically in carcinogen-induced rat and mouse mammary tumors and in "spontaneous" human mammary tumor lines. 2) Constitutive AhR activation is indicated by nuclear AhR localization in rat, mouse, and human mammary tumors and by AhR binding to gene promoters in the absence of environmental chemicals. 3) Constitutively active AhR regulates the expression of multiple genes, including CYP1B1, CK21, and Slug, a master regulator of tumor invasion. 4) Recent studies suggest that increased AhR activity in mammary tumors also contributes to cell migration and invasiveness. 5) Molecular downregulation of the AhR suppresses breast cancer cell proliferation and reverts cells to a non-aggressive phenotype. Molecular and biologic strategies have provided significant evidence that the AhR participates, beyond mutagenesis, in multiple mechanisms that contribute to tumor formation, growth and invasion. Therefore, we can exploit our ability to examine effects of constitutively active AhR to determine how chemical antagonism of the AhR may translate into breast cancer prevention or a therapeutic approach to suppress tumor progression. Thus, we propose a new hypothesis: Targeting the constitutively active AhR with naturally occurring, non-toxic antagonists represents a feasible therapeutic approach to inhibit breast tumor growth and invasion. Three specific aims are proposed: 1. Investigate strategies to maximize antagonism of the AhR by examining the potential for synergistic interaction in mixtures of antagonists, performing a high-throughput screen for novel, potent antagonists from natural product extract libraries (NCI Natural Products Repository) and examining the "chemical knockout" approach for improving AhR inactivation. 2. Define the molecular mechanisms of chemical antagonism of the constitutively active AhR in a breast cancer model by establishing antagonist effects on AhR transactivation of endogenous gene expression and examining antagonist-mediated changes in AhR-DNA interactions. 3. Establish the functional consequences of chemically antagonizing the constitutively active AhR using optimal AhR antagonists. The translational impact of these studies lies in the ability of known and newly identified antagonists to suppress tumor growth and invasion. Here, potentially therapeutic AhR antagonists will be evaluated for their ability to block the biological outcomes of constitutive AhR activity in human mammary tumor cell lines. Collectively, these studies will provide the foundation for preclinical studies on the potential for potent AhR antagonists to prevent and/or treat breast cancer in vivo. PUBLIC HEALTH RELEVANCE: We hypothesize that the hyper-expression of a protein, called the aryl hydrocarbon receptor, and its binding to DNA contributes to the growth and progression of breast tumors. Here we propose that chemicals that impede the function of this receptor (i.e. antagonists) will be effective at downregulating this protein's activity and therefore will suppress breast tumor growth and metastasis. Screening of plant and marine natural product libraries will provide a source of novel antagonists that can be tested for their interaction with this receptor and their mechanism of interference with tumor growth, ultimately resulting in the development of therapeutic agents for the treatment of breast cancer.

描述（由申请人提供）：历史上，已研究了芳香烃受体（AhR）对编码细胞色素P450酶的基因的转录调节，细胞色素P450酶将环境和内源性底物代谢为毒性和致突变中间体。越来越多的研究支持这一假设，即AhR除了在形成诱变剂和不存在环境化学物质的情况下发挥作用外，还在恶性上皮细胞生长和侵袭中发挥重要作用。这种新的范例是基于几个关键的观察：1）AhR的表达显着增加，在致癌物诱导的大鼠和小鼠乳腺肿瘤和“自发”的人乳腺肿瘤系。2)组成型AhR激活由大鼠、小鼠和人类乳腺肿瘤中的核AhR定位以及在不存在环境化学物质的情况下AhR与基因启动子结合指示。3)组成型活性AhR调节多个基因的表达，包括CYP 1B 1、CK 21和Slug，Slug是肿瘤侵袭的主要调节因子。4)最近的研究表明，乳腺肿瘤中AhR活性的增加也有助于细胞迁移和侵袭。5)AhR的分子下调抑制乳腺癌细胞增殖并使细胞恢复为非侵袭性表型。分子和生物学策略提供了重要的证据，AhR参与，超越诱变，在多种机制，有助于肿瘤的形成，生长和侵袭。因此，我们可以利用我们的能力来检查组成型活性AhR的作用，以确定AhR的化学拮抗作用如何转化为乳腺癌预防或抑制肿瘤进展的治疗方法。因此，我们提出了一个新的假设：靶向组成性活性AhR与天然存在的，无毒的拮抗剂代表了一种可行的治疗方法，以抑制乳腺肿瘤的生长和侵袭。提出了三个具体目标：1。通过检查拮抗剂混合物中协同相互作用的潜力，从天然产物提取物库（NCI Natural Products Repository）中高通量筛选新型强效拮抗剂，并检查用于改善AhR失活的“化学敲除”方法，研究最大化AhR拮抗作用的策略。2.通过建立对内源性基因表达的AhR反式激活的拮抗剂作用和检查AhR-DNA相互作用中拮抗剂介导的变化，定义乳腺癌模型中组成型活性AhR的化学拮抗作用的分子机制。3.建立使用最佳AhR拮抗剂化学拮抗组成型活性AhR的功能后果。这些研究的转化影响在于已知和新鉴定的拮抗剂抑制肿瘤生长和侵袭的能力。在此，将评价潜在治疗性AhR拮抗剂阻断人乳腺肿瘤细胞系中组成型AhR活性的生物学结果的能力。总的来说，这些研究将为有效的AhR拮抗剂在体内预防和/或治疗乳腺癌的潜力的临床前研究提供基础。公共卫生相关性：我们假设一种称为芳烃受体的蛋白质的超表达及其与DNA的结合有助于乳腺肿瘤的生长和进展。在这里，我们提出，阻碍这种受体功能的化学物质（即拮抗剂）将有效下调这种蛋白质的活性，因此将抑制乳腺肿瘤的生长和转移。植物和海洋天然产物库的筛选将提供新的拮抗剂的来源，可以测试它们与这种受体的相互作用及其干扰肿瘤生长的机制，最终导致开发用于治疗乳腺癌的治疗剂。