The role of the mTOR signaling pathway in ER-positive breast cancer

mTOR信号通路在ER阳性乳腺癌中的作用

• 批准号: 8496631
• 负责人: Marina K Holz
• 金额: $ 54.23万
• 依托单位: YESHIVA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8496631
• 关键词: Address; Affect; Apoptosis; Aromatase Inhibitors; Automobile Driving; Binding; Binding Sites; Biochemical; Biological Assay; Breast; Breast Cancer Cell; CCI-779; Cancer Cell Growth; Cancer Patient; Cell Nucleus; Cell Proliferation; Cells; Clinical; Clinical Trials; Combined Modality Therapy; Complex; Dependence; Development; Dimerization; Disease Progression; Drug Combinations; Endocrine; Enhancers; Ensure; Estrogen Antagonists; Estrogen Receptor 1; Estrogen Receptor Modulators; Estrogen Receptors; Estrogen receptor positive; Estrogens; Genes; Goals; Growth; Knowledge; Laboratories; Ligands; Malignant Neoplasms; Measurement; Mediating; Molecular; Pathogenesis; Pathway interactions; Patients; Pharmaceutical Preparations; Phosphorylation; Phosphotransferases; Promoter Regions; Proteins; RNA Interference; Receptor Activation; Regimen; Reporter; Research Design; Resistance; Resistance development; Ribosomal Protein S6 Kinase; Role; Signal Pathway; Signal Transduction; Students; System; Tamoxifen; Techniques; Therapeutic; Transactivation; Up-Regulation; Work; base; cell growth; chromatin immunoprecipitation; feeding; hormone therapy; improved; inhibitor/antagonist; insight; mTOR protein; malignant breast neoplasm; news; novel; novel therapeutics; prognostic; promoter; public health relevance; receptor; receptor binding; response; therapy development; transcription factor; tumor progression; tumorigenesis; undergraduate student

DESCRIPTION (provided by applicant): Background: Clinically, up to 60% of breast cancers are ER-positive, indicative of estrogen dependence for cancer cell growth. ER-positive breast cancers can be targeted therapeutically by antiestrogens (such as tamoxifen) or aromatase inhibitors (AIs). However, only about half of ER-positive breast cancers respond to endocrine treatments, and resistance frequently develops. An important clinical strategy is to use a combination therapy approach with inhibitors of other pathways in order to enhance the efficacy of endocrine therapy, and suppress the development or induce reversal of resistance. One of the most important pathways in regulating cellular growth and proliferation is the mammalian Target of Rapamycin Complex 1 (mTORC1). Inhibition of the mTORC1 pathway in combination with endocrine therapy has provided encouraging results in early clinical trials. Although great strides have been made in understanding the mechanisms of endocrine therapy sensitivity and emergence of resistance, the details are not fully understood. Objective/hypothesis: Our preliminary studies suggest that a co-regulatory relationship exists between the ER? and mTOR pathways, promoting breast cancer cell proliferation, specifically through estrogenic upregulation of a key mTOR effector, S6 Kinase 1 (S6K1, encoded by the RPS6KB1 gene), and mTORC1- mediated phosphorylation of ER? and 14-3-3?, and a novel protein SPATS2. Therefore, we propose to study the mechanistic, therapeutic and prognostic aspects of the relationship between mTORC1/S6K1 and ER pathways underlying disease progression and therapeutic resistance in breast cancer. Specific aims: We propose to investigate three distinct connections between the mTORC1 and ER pathways. We seek to (1) study mTORC1-mediated phosphorylation of 14-3-3? and SPATS2; (2) elucidate the mechanism of estrogenic expression of RPS6KB1; (3) define the role of mTORC1 signaling in ER? phosphorylation and activation. Study design: We will use Chromatin Immunoprecipitation (ChIP) to perform a comprehensive analysis of direct ER? binding to S6K1 promoter regions, and functional interactions with other transcription factors, such as GATA-3 and ERR?. To address the mode of mTOR-mediated phosphorylation of ER?, and the role of S6K1 target proteins, we will employ biochemical and cell-based measurements of kinase activity, and reporter assays for measurements of ER? transcriptional activity. Finally, we will use pharmacological and RNAi- mediated inhibition of these pathways to assess the phenotypic effects of these proteins on endocrine resistance. We will investigate changes in proliferative rates, growth, survival and apoptosis. Cancer relevance: Our proposal focuses on investigating the molecular mechanism by which ER cooperates with mTORC1 in regulating development and progression of cancer. Specifically, we would determine how this relationship affects sensitivity to endocrine therapy and development of resistance. The long-term goal is to improve therapeutic regiments for breast cancer patients by targeting patients most likely to benefit from a particular drug combination.

描述（由申请人提供）：背景：在临床上，多达60％的乳腺癌是ER阳性的，这表明雌激素对癌细胞生长的依赖性。 ER阳性乳腺癌可以通过抗雌激素（例如他莫昔芬）或芳香酶抑制剂（AIS）对靶向靶向。但是，只有大约一半的ER阳性乳腺癌对内分泌疗法做出反应，并且耐药经常发展。一个重要的临床策略是使用其他途径抑制剂的组合治疗方法，以增强内分泌治疗的功效，并抑制或诱导抗药性逆转。调节细胞生长和增殖的最重要途径之一是雷帕霉素复合物1（MTORC1）的哺乳动物靶标。在早期临床试验中，抑制MTORC1途径与内分泌疗法结合使用了令人鼓舞的结果。尽管在理解内分泌疗法敏感性和抗药性的出现方面取得了长足的进步，但细节尚未完全理解。客观/假设：我们的初步研究表明，ER之间存在共同调节关系？和MTOR途径，促进乳腺癌细胞增殖，特别是通过雌激素上调的MTOR效应子的雌激素上调，S6激酶1（S6K1，由RPS6KB1基因编码）和MTORC1介导的ER磷酸化？和14-3-3？和一种新型的蛋白质Spats2。因此，我们建议研究MTORC1/S6K1与ER途径之间疾病进展和乳腺癌治疗性抗性的机械，治疗和预后方面。具体目的：我们建议研究MTORC1和ER途径之间的三个不同的联系。我们寻求（1）研究MTORC1介导的14-3-3的磷酸化？和spats2; （2）阐明RPS6KB1的雌激素表达的机理； （3）定义MTORC1信号在ER中的作用？磷酸化和激活。研究设计：我们将使用染色质免疫沉淀（CHIP）对直接ER进行全面分析？与S6K1启动子区域的结合，以及与其他转录因子（例如GATA-3和ERR？）的功能相互作用。为了解决MTOR介导的ER磷酸化的模式，以及S6K1靶蛋白的作用，我们将采用生化和基于细胞的激酶活性测量和基于细胞的测量，以及记者测定法进行ER的测量吗？转录活动。最后，我们将使用对这些途径的药理和RNAI-介导的抑制作用来评估这些蛋白质对内分泌耐药性的表型作用。我们将研究增殖率，生长，生存和凋亡的变化。癌症相关性：我们的建议着重于研究ER与MTORC1合作在调节癌症发展和进展方面的分子机制。具体而言，我们将确定这种关系如何影响对内分泌治疗和抗性发展的敏感性。长期目标是通过针对最有可能受益于特定药物组合的患者来改善乳腺癌患者的治疗方案。