Elucidating and Leveraging the mTOR Negative Feedback Pathway in Breast Cancer

阐明和利用乳腺癌中的 mTOR 负反馈通路

• 批准号: 10278978
• 负责人: RUTH A. KERI
• 金额: $ 30.49万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2022-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10278978
• 关键词: Address; Antineoplastic Agents; Breast Cancer Cell; Breast Cancer Model; Breast Cancer therapy; Bypass; CCI-779; Cancer Cell Growth; Cell Survival; Cells; Clinical; Clinical Trials; Communication; Complex; Computing Methodologies; Dasatinib; Data; Dose-Limiting; Drug Targeting; Drug usage; ERBB2 gene; Elements; Epidermal Growth Factor Receptor; Estrogen Receptors; Estrogen receptor positive; FRAP1 gene; Feedback; Focal Adhesion Kinase 1; Focal Adhesions; Future; Gene Proteins; Genetic; Goals; Growth; Human; In Vitro; Individual; Integrins; Knowledge; Lead; Malignant Neoplasms; Mediating; Modeling; Molecular; Molecular Evolution; Molecular Profiling; Mouse Strains; Mutation; Outcome; PI3K/AKT; PTPN12 gene; Pathway interactions; Patients; Pharmaceutical Preparations; Phosphoric Monoester Hydrolases; Phosphotransferases; Play; Population; Process; Proteins; Proto-Oncogene Proteins c-akt; Receptor Protein-Tyrosine Kinases; Resistance; Role; Signal Pathway; Signal Transduction; Sirolimus; Source; Tamoxifen; Therapeutic; Toxic effect; Translations; Trastuzumab; Woman; Xenograft Model; Xenograft procedure; cell growth; combat; expectation; improved; improved outcome; in vivo; inhibitor/antagonist; innovation; insight; kinase inhibitor; mTOR Inhibitor; mTOR inhibition; malignant breast neoplasm; mouse model; neoplastic cell; novel; novel strategies; novel therapeutic intervention; phosphoproteomics; pre-clinical; predicting response; receptor; response; src-Family Kinases; targeted treatment; therapy outcome; therapy resistant; tool; transcriptomics; treatment response; triple-negative invasive breast carcinoma; tumor; tumor growth

PROJECT SUMMARY Targeted therapies have considerably improved survival from many cancers, including breast cancer. A major limitation of such therapies is resistance that occurs as a consequence of the extreme molecular evolution and adaptability of tumor cells. For targeted therapies to achieve their full potential of inducing sustained cures, they must be paired with additional agents that preclude activation of alternative growth and survival pathways. Identifying the most appropriate combinations requires a concerted effort to uncover mechanisms underlying activation of compensatory pathways. The PI3K/AKT/mTOR pathway is commonly activated in breast cancer. This proposal focuses on discovering new intermediaries of this signaling loop that can be targeted to improve the efficacy of mTOR inhibitors. Of the two mTOR complexes, rapalogs inhibit mTORC1 and protein translation. As single agents, rapalogs have limited efficacy in breast cancer, primarily due to feedback activation of AKT and induction of survival signals. Inhibitors of both mTORC1 and mTORC2 also cause AKT activation. Lastly, while dual inhibitors of PI3K and mTOR block this feedback pathway, they suffer from dose- limiting toxicities. These outcomes indicate that strictly targeting PI3K/AKT/mTOR is insufficient. We postulate that discerning the key elements within the negative feedback pathway that extends from mTOR to AKT will reveal novel targetable proteins for impeding rebound activation of AKT in response to mTOR inhibition. This should improve therapeutic outcomes without increasing toxicity. We used a computational method to reveal dasatinib, an inhibitor of Src Family Kinases (SFK) and Abl kinase, as a drug that may be highly synergistic with rapalogs. In breast cancer cells, dasatinib completely blocked the rebound activation of AKT that occurred with the rapalog, rapamycin. These two drugs also synergistically inhibited growth of triple negative breast cancer cells in vitro, and elicited tumor regression in multiple mouse models of breast cancer. These and other data revealed that at least one SFK resides within the pathway leading from mTOR to AKT and suggests that dual mTOR/SFK inhibition may be a novel approach to curtail resistance to mTOR inhibitors. Using phospho- proteomics and transcriptomics, we also found that focal adhesion signaling may be a major gateway for mTOR negative feedback signaling to AKT. We propose three aims to address these possibilities. In Aim 1, we will assess whether simultaneous blockade of SFKs and mTOR inhibits growth of patient derived xenografts of breast cancers as well as tumors that are resistant to current targeted therapies for HER2 and estrogen receptor. In Aim 2, we will interrogate the role of focal adhesion signaling in mediating mTOR feedback with the goal of leveraging this pathway for therapeutic benefit. Lastly, Aim 3 will uncover molecular signatures of resistance to mTOR/SFK inhibitors with the goal of revealing additional signaling inputs that control mTOR negative feedback. Together, these aims represent a comprehensive approach to discerning the molecular interplay between mTOR, elements of focal adhesions, and AKT in dictating tumor cell survival and growth.

项目概要 靶向治疗显着提高了包括乳腺癌在内的许多癌症的生存率。一个专业 这种疗法的局限性是由于极端的分子进化而产生的耐药性 肿瘤细胞的适应性。为了使靶向治疗充分发挥持续治愈的潜力， 它们必须与其他药物配合使用，以防止激活替代生长和生存途径。 确定最合适的组合需要共同努力来揭示潜在的机制 补偿途径的激活。 PI3K/AKT/mTOR 通路在乳腺癌中通常被激活。 该提案的重点是发现该信号循环的新中介，可以有针对性地改进 mTOR 抑制剂的功效。在两种 mTOR 复合物中，rapalogs 抑制 mTORC1 和蛋白质 翻译。作为单一药物，rapalogs 对乳腺癌的疗效有限，主要是由于反馈 AKT 的激活和生存信号的诱导。 mTORC1 和 mTORC2 抑制剂也会导致 AKT 激活。最后，虽然 PI3K 和 mTOR 的双重抑制剂阻断了这一反馈途径，但它们会遭受剂量- 限制毒性。这些结果表明严格针对 PI3K/AKT/mTOR 是不够的。我们假设 辨别从 mTOR 延伸到 AKT 的负反馈通路中的关键要素将 揭示了新的靶向蛋白，可阻止 AKT 响应 mTOR 抑制而反弹激活。这 应在不增加毒性的情况下改善治疗结果。我们使用计算方法来揭示 达沙替尼，Src 家族激酶 (SFK) 和 Abl 激酶的抑制剂，作为一种可能具有高度协同作用的药物 与rapalogs。在乳腺癌细胞中，达沙替尼完全阻断了 AKT 的反弹激活 与rapalog，雷帕霉素。这两种药物还协同抑制三阴性乳腺的生长 体外癌细胞，并在多种乳腺癌小鼠模型中引起肿瘤消退。这些和其他 数据显示至少有一个 SFK 存在于从 mTOR 到 AKT 的通路中，并表明 mTOR/SFK 双重抑制可能是减少 mTOR 抑制剂耐药性的新方法。使用磷 蛋白质组学和转录组学，我们还发现粘着斑信号传导可能是 mTOR 向 AKT 发出负反馈信号。我们提出三个目标来解决这些可能性。在目标 1 中，我们 将评估同时阻断 SFK 和 mTOR 是否会抑制患者来源的异种移植物的生长 乳腺癌以及对当前 HER2 和雌激素靶向治疗有耐药性的肿瘤 受体。在目标 2 中，我们将探讨粘着斑信号传导在介导 mTOR 反馈中的作用 利用该途径获得治疗益处的目标。最后，Aim 3 将揭示以下分子特征： 对 mTOR/SFK 抑制剂的耐药性，目的是揭示控制 mTOR 的其他信号输入 负面反馈。总之，这些目标代表了一种识别分子的综合方法。 mTOR、粘着斑元件和 AKT 之间的相互作用决定肿瘤细胞的存活和生长。