Probing a novel signaling complex that sustains AKT activation to support stress survival in cancer

探索维持 AKT 激活以支持癌症应激生存的新型信号复合物

• 批准号: 10536863
• 负责人: Matthew R Zanotelli
• 金额: $ 6.72万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10536863
• 关键词: 1-Phosphatidylinositol 3-Kinase; Aggressive behavior; Anchorage-Independent Growth; Anoikis; Binding; Biochemical; C2 Domain; Cancer cell line; Cell Survival; Cells; Cellular Stress; Characteristics; Complex; Cytokinesis; Dimerization; Docking; Exhibits; Exposure to; FRAP1 gene; Family member; GTP Binding; Genetic; Growth; Growth Factor; Guanine Nucleotide Exchange Factors; Human; Individual; Intervention; Laboratories; Lipid Binding; Location; Lysosomes; Maintenance; Malignant - descriptor; Malignant Neoplasms; Mediating; Membrane; Metabolism; Nutrient; Oncogenic; Outcome; Phenotype; Phospholipids; Phosphorylation; Play; Proteins; Proto-Oncogene Proteins c-akt; Ribosomal Protein S6 Kinase; Role; Serum; Signal Pathway; Signal Transduction; Site; Starvation; Stress; Surface; Therapeutic Intervention; Work; biological adaptation to stress; cancer cell; cancer survival; cancer therapy; cell transformation; insight; new therapeutic target; novel; nutrient deprivation; scaffold; targeted treatment; therapeutic target; tumor metabolism; tumor progression; tumorigenesis

PROJECT SUMMARY Abnormal metabolism is a hallmark of cancer that helps cancer cells to grow, undergo malignant transformation, and survive under stressful conditions such as nutrient deprivation. Cancer cells are exposed to many cellular stresses during tumorigenesis, which must be overcome for the propagation of malignancy. In cancer, the abnormal activation of many signaling networks serves to disconnect the control of growth, metabolism, and survival, and recent efforts have sought to therapeutically target cancer metabolism. The phosphatidylinositol 3- kinase (PI3K)-AKT (protein kinase B) signaling pathway is the most activated in human cancer and has a wide range of effects on cellular metabolism. We have recently identified the Cdc42/Rac guanine nucleotide exchange factor (GEF) dedicator of cytokinesis 7 (Dock7) as a novel signaling node that supports sustained basal AKT activation and mechanistic target of rapamycin (mTOR) activity as determined by its downstream target S6 kinase (S6K) during stressful conditions to maintain signaling activity required for cell survival and transformation. We find that Dock7 is required for multiple cancer cell lines to resist anoikis and exhibit anchorage-independent growth. While we observe relatively low levels of AKT phosphorylation compared to stimulation by growth factors, Dock7-dependent signaling is critical for the survival of cancer cells during nutrient deprivation. I hypothesize that under cellular stress Dock7 serves as a scaffold for AKT, sustaining its phosphorylation and organizing signaling partners for mTOR signaling required for stress survival. This project will investigate the role of this novel Dock7/AKT/mTOR signaling activity in providing a survival benefit to cancer cells under cellular stress. I propose to study the impact of Dock7-dependent signaling activity on AKT/mTOR signaling, cell survival under stress, and critical characteristics of malignant progression and aggression. In Aim 1, I will investigate the functional activities of the Dock-homology region 2 (DHR2) domain of Dock7, which is responsible for GEF activity, in basal AKT phosphorylation for cancer cell stress survival and malignant transformation. In Aim 2, I will next identify the novel role of the DHR1 domain in Dock7-dependent AKT phosphorylation, cancer cell stress survival, and malignant transformation. Then, in Aim 3, I will identify the subcellular location of this Dock7 signaling complex under stress conditions and determine the individual roles of DHR1, DHR2, and activated Cdc42 in Dock7 localization. The work in this proposal will provide biochemical characterization of Dock7 signaling activity that will lead to a mechanistic understanding of Dock7-dependent AKT/mTOR activation in cancer cell stress survival. These findings will not only contribute to the understanding of cancer aggression and metabolism but may also identify new therapeutic targets for cancer treatment.

项目总结 新陈代谢异常是癌症的一个标志，有助于癌细胞生长、恶性转化、 并在营养缺乏等压力条件下生存。癌细胞暴露于许多细胞 在肿瘤形成过程中必须克服的压力，以促进恶性肿瘤的传播。在癌症方面， 许多信号网络的异常激活导致生长、新陈代谢和 存活率，最近的努力试图从治疗上针对癌症新陈代谢。磷脂酰肌醇3- 蛋白激酶B(Protein Kinase B，PI3K)-AKT(Protein Kinase B)信号通路是人类癌症中最活跃的信号通路，具有广泛的 对细胞新陈代谢的影响范围。我们最近发现了cdc42/rac鸟嘌呤核苷酸交换。 胞质分裂因子7(DOCK7)作为新的信号转导节点支持持续的基础AKT 雷帕霉素(MTOR)活性的激活及其机制靶点由其下游靶点S6决定 蛋白激酶(S6K)在应激条件下维持细胞生存和转化所需的信号活性。 我们发现DOCK7是多种癌细胞抵抗失巢凋亡并表现出锚定非依赖性所必需的 成长。虽然我们观察到与生长因子刺激相比，AKT的磷酸化水平相对较低， DOCK7依赖的信号对癌细胞在营养缺乏期间的生存至关重要。我假设 在细胞应激下，DOCK7作为AKT的支架，维持其磷酸化和组织化 应激生存所需的mTOR信号伙伴的信号伙伴。该项目将调查这一角色 新的DOCK7/AKT/mTOR信号活性在细胞应激下为癌细胞提供生存益处。我 建议研究DOCK7依赖的信号活性对AKT/mTOR信号、细胞存活的影响 应激，以及恶性进展和攻击性的关键特征。在目标1中，我将调查 负责全球环境基金的DOCK7的DHR2结构域的功能活性 活性，在基础AKT磷酸化对癌细胞的应激生存和恶变。在目标2中，我 接下来将确定DHR1结构域在DOCK7依赖的AKT磷酸化、癌细胞应激中的新作用 生存和恶变。然后，在目标3中，我将确定DOCK7的亚细胞位置 应激条件下的信号复合体，并确定DHR1、DHR2和激活的单独作用 CDC42在DOCK7定位。本提案中的工作将提供DOCK7的生化特性 信号活动将导致对DOCK7依赖的AKT/mTOR激活的机械性理解 癌细胞应激存活。这些发现不仅有助于理解癌症侵袭性和 这不仅有助于新陈代谢，还可能为癌症治疗确定新的治疗靶点。