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: 10689065
• 负责人: Matthew R Zanotelli
• 金额: $ 6.95万
• 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/10689065
• 关键词: 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; PIK3CG gene; 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.

项目摘要 异常代谢是癌症的标志，可帮助癌细胞生长，发生恶性转化， 并在压力条件下生存，例如养分剥夺。癌细胞暴露于许多细胞 肿瘤发生过程中的应力，这必须克服恶性肿瘤的传播。在癌症中 许多信号网络的异常激活可以断开对生长，代谢和的控制 生存以及最近的努力试图以治疗靶向癌症代谢。磷脂酰肌醇3- 激酶（PI3K）-akt（蛋白激酶B）信号传导途径在人类癌症中最激活，并且具有广泛的 对细胞代谢的影响范围。我们最近确定了CDC42/RAC鸟嘌呤核苷酸交换 细胞因子7（DOCK7）的因子（GEF）作为支持基础Akt持续的新信号节点 雷帕霉素（MTOR）活性的激活和机械靶标由其下游靶标S6确定 在压力条件下，激酶（S6K）保持细胞存活和转化所需的信号活性。 我们发现多个癌细胞系需要Dock7来抵抗Anoikis并表现出与锚固无关的 生长。虽然我们观察到与生长因子刺激相比，Akt磷酸化水平相对较低，但 DOCK7依赖性信号传导对于养分剥夺过程中癌细胞的存活至关重要。我假设 在细胞应力下，Dock7是Akt的支架，维持其磷酸化并组织 压力存活所需的MTOR信号传导的信号伴侣。该项目将调查此的作用 新型Dock7/Akt/MTOR信号传导活性在细胞应激下为癌细胞提供生存益处。我 建议研究DOCK7依赖性信号传导活性对Akt/mTOR信号传导的影响 压力和恶性进展和攻击的临界特征。在AIM 1中，我将调查 DOCK7的Dock-同源区2（DHR2）域的功能活动，该域负责GEF 活性，用于癌细胞应激存活和恶性转化的基础AKT磷酸化。在AIM 2中，我 接下来，将确定DHR1结构域在DOCK7依赖性AKT磷酸化，癌细胞应激中的新作用 生存和恶性转化。然后，在AIM 3中，我将确定此DOCK7的亚细胞位置 在应力条件下信号传导复合物并确定DHR1，DHR2的各个角色并激活 DOCK7本地化中的Cdc42。该提案中的工作将提供Dock7的生化特征 信号传导活性将导致对DOCK7依赖性AKT/MTOR激活的机械理解 癌细胞应激存活。这些发现不仅有助于理解癌症的侵略和 代谢，但也可能确定用于癌症治疗的新治疗靶标。