Role of NRF-1 in Estrogen-Induced Breast Cancer Pathogenesis

NRF-1 在雌激素诱导的乳腺癌发病机制中的作用

• 批准号: 8332969
• 负责人: DEODUTTA ROY
• 金额: --
• 依托单位: MIAMI VA HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-10-01 至 2016-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8332969
• 关键词: 3-Dimensional; Acetylation; Acetyltransferase; Address; Affect; Antioxidants; Binding; Biochemical; Biological Assay; Biological Markers; Breast; Breast Cancer Cell; Breast Cancer Prevention; Breast Cancer Risk Factor; Breast Cancer Treatment; CXCR4 gene; Cancer Prognosis; Cell Culture Techniques; Cell model; Chemicals; Chronic; Clinical; DNA; Deacetylase; Development; Disease; Dominant-Negative Mutation; Enzymes; Estrogen Receptor Status; Estrogens; Exposure to; Foundations; Gene Silencing; Gene Targeting; Genetic; Genetic Transcription; Goals; Growth; Histone Acetylation; Human; Hydrogen Peroxide; Hysterectomy; Image; Immunoprecipitation; In Vitro; Incidence; Individual; Knowledge; Lesion; Malignant - descriptor; Mammary Gland Parenchyma; Mammary Neoplasms; Manganese Superoxide Dismutase; Mediating; Military Personnel; Modeling; Molecular; Molecular Target; Nude Mice; Oral Contraceptives; Oxidation-Reduction; PCAF gene; PI3K/AKT; PTEN gene; Pathogenesis; Pathway interactions; Phosphorylation; Population; Predisposition; Prevalence; Prevention; Prevention strategy; Procedures; Proteins; Reactive Oxygen Species; Recruitment Activity; Research; Reverse Transcriptase Polymerase Chain Reaction; Risk; Risk Factors; Role; SMYD3 gene; Services; Signal Transduction; Signal Transduction Pathway; Signaling Molecule; Specimen; Staging; Techniques; Testing; Time; Translating; Veterans; Western Blotting; Woman; Xenograft Model; Xenograft procedure; arm; base; breast cancer diagnosis; breast lesion; cancer initiation; carcinogenesis; catalase; cell transformation; chromatin modification; clinically significant; ebselen; high risk; hormone therapy; in vivo; inhibitor/antagonist; malignant breast neoplasm; malignant phenotype; member; mouse model; novel; nuclear respiratory factor; overexpression; oxidation; prevent; promoter; therapeutic target; tool; transcription factor; tumor; tumor progression

DESCRIPTION (provided by applicant): Exposure to exogenous estrogen used in oral contraceptives (OCs) and hormone therapy (HT) is a major risk factor for breast cancer initiation and progression in women including veteran population. The signaling mechanisms by which estrogen contributes in the initiation or the progression of breast cancer are not fully understood. Understanding the exact molecular mechanisms by which breast cancer lesions arise upon chronic estrogen exposure could have major clinical implications for preventing or circumventing the disease. The overall goal of this proposal is to test a new paradigm that reactive oxygen species (ROS)-mediated activation of NRF-1 may contribute to predisposing veteran and civilian women to estrogen-induced breast cancer. This paradigm will be tested using: state of the art molecular tools, in vitro 2-D/3-D cell models, [human breast tissue specimens] and in vivo xenograft model. We and others have found that ROS are important signaling molecules, which contribute in the development of estrogen-induced malignant breast lesions. However, the molecular signaling mechanism by which ROS contribute to breast cancer susceptibility is not clear. Recent findings suggest the existence of other mechanism(s) independent of ER status that mediate estrogen- induced cell signaling leading to malignant transformation and growth of breast cancer cells. One such mechanism being investigated by us is the role of estrogen-induced ROS in breast carcinogenesis. Recently, we have observed that (i) estrogen-induced breast tumor formation in the xenograft model was inhibited by overexpression of the antioxidant enzyme, catalase, that lowers the level of H2O2 or by co- treatment with a chemical antioxidant, ebselen, that scavenges ROS; and (ii) NRF-1 overexpression supported tumor formation while NRF-1 knockdown reduced tumor formation. These findings suggest that ROS-induced NRF-1 activation may be a determinant of susceptibility to estrogen-induced breast cancer. Hypothesis: The above observations form the foundation of our hypothesis that ROS promotes susceptibility to estrogen-induced breast carcinogenesis by affecting the redox sensitive protein NRF-1 because modulation of NRF-1 affects breast tumor formation. Objectives: To address the above hypothesis, we propose three Specific Aims: (1) To determine that estrogen-induced ROS are essential for phosphorylation and acetylation of NRF-1. (2) To determine that estrogen-induced ROS control the transcription of target genes by (i) phosphorylation and acetylation of the NRF-1 transcription factor, and (ii) chromatin modifications via DNA oxidation and histone acetylation. (3) To determine whether pharmacological or genetic disruption of ROS and/or NRF-1 prevents the development of estrogen-induced mammary tumors. Procedures to be used: The study will be conducted using in vitro 2-D and 3-D cell culture models and findings will be further validated [in human breast tissue specimens] and in vivo by the xenograft nude mice model. This study will employ state of the art biochemical and molecular techniques, including gene silencing, immunoprecipitation, Western blotting, confocal imaging, ChIP, Real-Time RT-PCR, and cell transformation assays. Significance of potential new findings: The results of our proposed studies will elucidate, for the first time, the molecular mechanism by which estrogen-induced ROS regulates phosphorylation and acetylation of the transcription factor NRF-1 and define the role of NRF-1 signaling in estrogen-induced breast cancer pathogenesis that may prove useful therapeutic targets for the prevention and treatment of breast cancer. Furthermore, the findings from our study may set the stage to assess if phosphorylated and/or acetylated NRF-1 can serve as a valuable biomarker for breast cancer diagnosis and prognosis.

描述（由申请人提供）： 暴露于口服避孕药（OC）和激素治疗（HT）中使用的外源性雌激素是女性（包括退伍军人）乳腺癌发生和进展的主要危险因素。雌激素促进乳腺癌发生或进展的信号传导机制尚不完全清楚。了解长期接触雌激素后乳腺癌病变发生的确切分子机制可能对预防或规避该疾病具有重大的临床意义。该提案的总体目标是测试一种新的范例，即活性氧 (ROS) 介导的 NRF-1 激活可能有助于退伍军人和平民妇女罹患雌激素诱发的乳腺癌。该范例将使用最先进的分子工具、体外 2-D/3-D 细胞模型、[人类乳腺组织标本]和体内异种移植模型进行测试。我们和其他人发现，ROS 是重要的信号分子，有助于雌激素诱导的恶性乳腺病变的发展。然而，ROS 导致乳腺癌易感性的分子信号机制尚不清楚。最近的研究结果表明，存在与 ER 状态无关的其他机制，介导雌激素诱导的细胞信号传导，导致乳腺癌细胞的恶性转化和生长。我们正在研究的一种机制是雌激素诱导的 ROS 在乳腺癌发生中的作用。最近，我们观察到，（i）异种移植模型中雌激素诱导的乳腺肿瘤形成受到抗氧化酶过氧化氢酶过度表达的抑制，过氧化氢酶可降低 H2O2 水平，或与化学抗氧化剂依布硒啉共同治疗，可清除 H2O2活性氧； (ii) NRF-1 过表达支持肿瘤形成，而 NRF-1 敲低则减少肿瘤形成。这些发现表明，ROS 诱导的 NRF-1 激活可能是雌激素诱导的乳腺癌易感性的决定因素。 假设：上述观察结果构成了我们假设的基础，即ROS通过影响氧化还原敏感蛋白NRF-1来促进雌激素诱导的乳腺癌发生的易感性，因为NRF-1的调节会影响乳腺肿瘤的形成。 目的：为了解决上述假设，我们提出了三个具体目标：（1）确定雌激素诱导的 ROS 对于 NRF-1 的磷酸化和乙酰化至关重要。 (2) 确定雌激素诱导的 ROS 通过 (i) NRF-1 转录因子的磷酸化和乙酰化，以及 (ii) 通过 DNA 氧化和组蛋白乙酰化进行染色质修饰来控制靶基因的转录。 (3) 确定 ROS 和/或 NRF-1 的药理学或遗传破坏是否可以预防雌激素诱导的乳腺肿瘤的发展。 使用程序：该研究将使用体外 2-D 和 3-D 细胞培养模型进行，研究结果将在[人类乳腺组织标本]和体内通过异种移植裸鼠模型进一步验证。这项研究将采用最先进的生化和分子技术，包括基因沉默、免疫沉淀、蛋白质印迹、共聚焦成像、ChIP、实时 RT-PCR 和细胞转化测定。 潜在新发现的意义：我们提出的研究结果将首次阐明雌激素诱导的 ROS 调节转录因子 NRF-1 磷酸化和乙酰化的分子机制，并定义 NRF-1 信号在雌激素诱导的乳腺癌发病机制可能被证明是预防和治疗乳腺癌的有用治疗靶点。此外，我们的研究结果可能为评估磷酸化和/或乙酰化 NRF-1 是否可以作为乳腺癌诊断和预后的有价值的生物标志物奠定基础。