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.

项目概要 代谢异常是癌症的标志，有助于癌细胞生长、恶性转化、 并在营养匮乏等压力条件下生存。癌细胞暴露于多种细胞 肿瘤发生过程中的应激，必须克服这些应激才能促进恶性肿瘤的传播。在癌症中， 许多信号网络的异常激活会断开对生长、代谢和生长的控制。 生存率，最近的努力试图以癌症代谢为目标进行治疗。磷脂酰肌醇3- 激酶 (PI3K)-AKT（蛋白激酶 B）信号通路是人类癌症中最活跃的信号通路，具有广泛的应用前景。 对细胞代谢的一系列影响。我们最近鉴定了 Cdc42/Rac 鸟嘌呤核苷酸交换 胞质分裂 7 (Dock7) 因子 (GEF) 奉献者作为支持持续基础 AKT 的新型信号传导节点 雷帕霉素 (mTOR) 活性的激活和机制目标由其下游靶标 S6 决定 激酶 (S6K) 在应激条件下维持细胞生存和转化所需的信号活动。 我们发现多种癌细胞系需要 Dock7 来抵抗失巢凋亡并表现出锚定依赖性 生长。虽然我们观察到与生长因子的刺激相比 AKT 磷酸化水平相对较低， Dock7 依赖性信号传导对于营养剥夺期间癌细胞的生存至关重要。我假设 在细胞应激下，Dock7 充当 AKT 的支架，维持其磷酸化并组织 应激生存所需的 mTOR 信号传导合作伙伴。该项目将调查该项目的作用 新颖的 Dock7/AKT/mTOR 信号传导活性可为癌细胞在细胞应激下提供生存益处。我 提议研究 Dock7 依赖性信号传导活性对 AKT/mTOR 信号传导、细胞存活的影响 压力以及恶性进展和攻击的关键特征。在目标 1 中，我将调查 Dock7 的 Dock 同源区 2 (DHR2) 结构域的功能活动，负责 GEF 基础 AKT 磷酸化对癌细胞应激存活和恶性转化的活性。在目标 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 生存和恶变。然后，在目标 3 中，我将识别这个 Dock7 的亚细胞位置 压力条件下的信号复合体并确定 DHR1、DHR2 和激活的个体作用 Dock7 本地化中的 Cdc42。本提案中的工作将提供 Dock7 的生化特征 信号活动将导致对 Dock7 依赖性 AKT/mTOR 激活的机制的理解 癌细胞应激生存。这些发现不仅有助于了解癌症的侵袭性， 代谢，但也可能确定癌症治疗的新治疗靶点。