Role of Akt isoforms in PTEN-deficient breast cancer

Akt 亚型在 PTEN 缺陷乳腺癌中的作用

• 批准号: 9115910
• 负责人: Abbe Rose Clark
• 金额: $ 3.61万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9115910
• 关键词: Alpha Cell; Automobile Driving; Breast Cancer Cell; Breast Cancer Patient; Breast Cancer Treatment; Cancer Patient; Cell physiology; Cellular Assay; Chimera organism; Complex; Data; Development; Disease; Functional disorder; Goals; Growth; Human; In Vitro; Knowledge; Malignant Neoplasms; Mammary Neoplasms; Mass Spectrum Analysis; Mediating; Molecular; Mutation; Oncogenes; Oncogenic; PTEN Gene Inactivation; PTEN gene; Pathway interactions; Phenotype; Phosphatidylinositols; Phosphorylation; Phosphotransferases; Physiological; Process; Protein Isoforms; Publishing; Regulation; Research; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Specificity; Substrate Specificity; Therapeutic; Tumor Suppressor Proteins; Tumorigenicity; Work; clinical development; clinically relevant; experimental study; human disease; in vivo; inhibitor/antagonist; insight; malignant breast neoplasm; migration; mouse model; mutational status; new therapeutic target; novel; phosphoproteomics; prostate cancer cell; public health relevance; research clinical testing; therapeutic target; tool; tumor initiation; tumor progression; tumorigenesis; tumorigenic

 DESCRIPTION (provided by applicant): A complex network of signaling pathways controls the fundamental physiological activities of a cell, such as growth, migration and survival. Hence, perturbations of these pathways serve as the molecular basis underlying a wide range of human diseases, including cancer. A thorough understanding of the molecular mechanisms by which altered cellular signaling processes drive these diseases will greatly facilitate our ability to trat these conditions. In breast cancer, one of the most frequently dysregulated signaling pathways is the phosphoinositide 3-kinase (PI3K)/Akt cascade. Frequent mutation of the oncogene PI3K or inactivation of the tumor suppressor PTEN leads to hyperactivation of Akt, which promotes tumorigenesis through its downstream effectors. There are three isoforms of Akt (Akt1, Akt2 and Akt3). Our lab, among others, has demonstrated that Akt isoforms have non-redundant functions in the regulation of tumor progression. However, there is a paucity of knowledge regarding the mechanisms by which specific Akt isoforms signal to control these phenotypes. Newly published data from our lab supports an exclusive role for Akt2 in breast cancer cells with inactive PTEN. The main objective of this proposal is to determine the mechanism by which Akt2 isoform-specificity is conferred in PTEN-inactive breast cancer. The central hypothesis driving this proposal is that Akt2 isoform-specificity in PTEN-inactivate breast cancer is conferred by intrinsic molecular determinants that regulate phosphorylation of isoform-specific substrates controlling tumorigenesis. The outlined experiments will: (i) determine the oncogenic phenotypes of PTEN-inactive breast cancer cells exclusively regulated by Akt2 using in vitro cellular assays to assess the effect of Akt2-specific silencing on proliferation, growth, survival and invasive migration; (ii) identify and characterize novel Akt2-specific substrates in PTEN-inactive breast cancer cells using a SILAC global mass spectrometry phospho-proteomic screen; and (iii)determine whether molecular determinants on Akt2 define Akt2 isoform-specificity in the context of PTEN-inactivation using chimeras of swapped domains of Akt1 and Akt2 and performing in vitro cellular assays to rescue phenotypes associated with Akt2-silencing in PTEN-inactive breast cancer cells. The proposed research is novel given our poor mechanistic understanding of Akt isoform-specific signaling, particularly in the context of specifi PI3K-pathway mutations. The results of this work will fill a critical gap in our understanding of Akt isoform-specificity and have important implications for the development of clinically-relevant, isoform-specific inhibitors. Such inhibitors would provide a potential therapeutic opportunity to regulate the pro-tumorigenic activities of Akt2 in PTEN-inactivate breast cancer. Furthermore, identification of Akt isoform-specific substrates that regulate tumor progression will provide a se of novel targets with therapeutic potential. Collectively, these approaches will contribute to our long-term goal of tailoring therapeutic strategies to treat breast cancer patients with hyperactivated PI3K/Akt signaling.

 描述（由申请人提供）：信号通路的复杂网络控制细胞的基本生理活动，如生长、迁移和存活。因此，这些途径的扰动是包括癌症在内的多种人类疾病的分子基础。彻底了解改变的细胞信号传导过程驱动这些疾病的分子机制将大大促进我们治疗这些疾病的能力。在乳腺癌中，最常见的失调信号通路之一是磷酸肌醇3-激酶（PI 3 K）/Akt级联。癌基因PI 3 K的频繁突变或肿瘤抑制因子PTEN的失活导致Akt的过度活化，其通过其下游效应物促进肿瘤发生。Akt有三种亚型（Akt 1、Akt 2和Akt 3）。我们的实验室，除其他外，已经证明Akt亚型在调节肿瘤进展中具有非冗余功能。然而，关于特定Akt亚型信号控制这些表型的机制的知识很少。 我们实验室新发表的数据支持Akt 2在具有失活PTEN的乳腺癌细胞中的独特作用。该提案的主要目的是确定Akt 2亚型特异性在PTEN失活乳腺癌中被赋予的机制。推动这一提议的中心假设是，PTEN-B1乳腺癌中的Akt 2亚型特异性由调节控制肿瘤发生的亚型特异性底物的磷酸化的内在分子决定簇赋予。概述的实验将：（i）使用体外细胞测定确定仅由Akt 2调节的PTEN失活乳腺癌细胞的致癌表型，以评估Akt 2特异性沉默对增殖、生长、存活和侵入性迁移的影响;和（iii）使用Akt 1和Akt 2交换结构域的嵌合体并进行体外细胞测定以拯救与PTEN失活乳腺癌细胞中Akt 2沉默相关的表型，确定Akt 2上的分子决定簇是否在PTEN失活的情况下定义Akt 2同种型特异性。 鉴于我们对Akt亚型特异性信号传导的机制理解不佳，特别是在特定PI 3 K通路突变的背景下，所提出的研究是新颖的。这项工作的结果将填补我们对Akt亚型特异性理解的关键空白，并对临床相关， 异构体特异性抑制剂。这种抑制剂将提供一个潜在的治疗机会，以调节Akt 2在PTEN-β乳腺癌中的促肿瘤发生活性。此外，Akt亚型特异性底物的鉴定，调节肿瘤的进展将提供一系列新的治疗潜力的目标。总的来说，这些方法将有助于我们的长期目标，定制治疗策略，以治疗PI 3 K/Akt信号过度激活的乳腺癌患者。