Cell Fate Control by Integrated E2F, FoxO and PI3K Signaling in Retinoblastoma

视网膜母细胞瘤中集成 E2F、FoxO 和 PI3K 信号传导的细胞命运控制

• 批准号: 8688176
• 负责人: Timothy C. Hallstrom
• 金额: $ 30.59万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2018-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8688176
• 关键词: Address; Affect; Apoptosis; Apoptotic; Bilateral; Binding; Binding Proteins; Biochemical; Biological; Cancerous; Cell Cycle; Cell Death; Cell Fate Control; Cell Proliferation; Cell division; Cells; ChIP-on-chip; ChIP-seq; Chromatin; Clinical Trials; Complex; Coupled; DNA biosynthesis; Data; Development; Disabled Persons; Dominant-Negative Mutation; E2F transcription factors; E2F1 gene; Equilibrium; Feedback; Functional disorder; Gene Expression; Gene Targeting; Genes; Genetic Transcription; Goals; Growth; Human; Induction of Apoptosis; Knowledge; Malignant Neoplasms; Mediating; Medical; Mitotic; Modeling; Molecular; Mus; Mutate; Mutation; Nature; Normal Cell; Oncogenic; PTEN gene; Pathway interactions; Patients; Phosphorylation; Play; Proteins; Public Health; RB1 gene; Regulation; Research; Retina; Retinal; Retinoblastoma; Retinoblastoma Protein; Role; Signal Pathway; Signal Transduction; Solid Neoplasm; Staging; Stress; Structure; Testing; Therapeutic; Treatment Efficacy; Tumor Suppression; Tumor Suppressor Genes; Work; cancer cell; cancer therapy; cell killing; chromatin immunoprecipitation; in vivo; innovation; insight; mouse model; neoplastic cell; novel; novel strategies; programs; promoter; public health relevance; research clinical testing; research study; response; retinoblastoma tumor suppressor; screening; standard of care; transcription factor; transcriptome sequencing; tumor; tumor initiation; tumorigenesis

DESCRIPTION (provided by applicant): The E2F transcription factors induce proliferation but also can promote cell death as an innate anti-cancer mechanism to kill cells with a spontaneous oncogenic mutation that might otherwise go on to form a cancer. Little is known about the molecular circuitry that tips E2F1 balance towards proliferation in some settings (normal growth), apoptosis in others (oncogenic stress/incipient cancers), and which pathways mediate this decision. Lack of such knowledge is an important unmet medical problem, because without it, acquiring the ability to restore latent E2F1 mediated apoptotic activity therapeutically in tumors to accelerate tumor cell death is highly unlikely. We discovered that the PI3K/Akt pathway, which is frequently activated in human cancer, is a key negative regulator of E2F1 induced apoptosis and apoptotic target gene expression. These findings suggest that function of E2F1, a traditionally "undruggable" target molecule (transcription factor) can be modulated towards apoptosis by interfering with PI3K activity. We also show that the FoxO1 transcription factor physically interacts with E2F1 and can bind to the same promoters to regulate gene expression and apoptosis. The major hypothesis tested in this proposal is that E2F1 and FoxO1 transcription factors coordinate a tumor suppressive apoptotic transcriptional program that can be inhibited by Akt activation. Aim 1 will focus on a) identifying domains in E2F1 and FoxO1 required for interaction and function, b) will determine if other E2Fs and FoxOs interact, and c) employ an IP-Mass Spec strategy to determine other E2F1 binding partners that may regulate the function of the E2F1/FoxO1 complex and coordinate its pro-apoptotic function. Aim 2 delves into identification of co-regulated E2F1 and FoxO1 target genes and the mechanisms of gene expression using qPCR, RNA-Seq, ChIP, and ChIP-Seq. Aim 3 tests FoxO and Pten/PI3K/Akt pathway regulation of Rb/E2F apoptosis and tumorigenesis in vivo in the mouse retina. We also propose to use our mouse model, which develops aggressive bilateral retinoblastoma, for pre-clinical testing anti-PI3K therapy with or without current standard of care treatment. Our finding that FoxO and PI3K activity facilitate control of the E2F1 apoptotic and proliferative balance suggest that these studies will provide significant insight into the mechanistic relationship between these proteins in normal and cancerous cells. The experiments outlined in this proposal will provide important information about the function of the E2F1/FoxO complex, its regulation by PI3K signaling, and the extent that inhibiting PI3K in vivo may be a therapeutic option aiming at restoring E2F1/FoxO apoptosis stimulation in tumors. Considering that dysfunction in Rb/E2F and PI3K/Pten pathways feature prominently in numerous human tumors, we expect that our findings may be applicable to other tumor types.

描述（由申请人提供）：E2F转录因子诱导增殖，但也可以作为一种先天抗癌机制促进细胞死亡，以杀死具有自发致癌突变的细胞，否则这些细胞可能会继续形成癌症。对于在某些情况下（正常生长）使 E2F1 趋于增殖、在另一些情况下（致癌应激/初期癌症）细胞凋亡的分子回路以及哪些途径介导这一决定，我们知之甚少。缺乏这样的知识是一个重要的未解决的医学问题，因为如果没有它，就不可能获得在肿瘤中恢复潜在的 E2F1 介导的细胞凋亡活性以加速肿瘤细胞死亡的治疗能力。我们发现，在人类癌症中频繁激活的 PI3K/Akt 通路是 E2F1 诱导细胞凋亡和凋亡靶基因表达的关键负调节因子。这些发现表明，传统上“不可成药”的靶分子（转录因子）E2F1 的功能可以通过干扰 PI3K 活性来调节至细胞凋亡。我们还表明，FoxO1 转录因子与 E2F1 存在物理相互作用，并且可以结合相同的启动子来调节基因表达和细胞凋亡。该提案测试的主要假设是 E2F1 和 FoxO1 转录因子协调肿瘤抑制性细胞凋亡转录程序，该程序可被 Akt 激活抑制。目标 1 将重点关注 a) 识别 E2F1 和 FoxO1 中相互作用和功能所需的结构域，b) 将确定其他 E2F 和 FoxO 是否相互作用，以及 c) 采用 IP-质谱策略来确定可能调节 E2F1/FoxO1 复合物功能并协调其促凋亡功能的其他 E2F1 结合伴侣。目标 2 深入研究使用 qPCR、RNA-Seq、ChIP 和 ChIP-Seq 来鉴定共同调控的 E2F1 和 FoxO1 靶基因以及基因表达机制。 Aim 3 测试 FoxO 和 Pten/PI3K/Akt 通路对小鼠视网膜体内 Rb/E2F 细胞凋亡和肿瘤发生的调节。我们还建议使用我们的小鼠模型（该模型会产生侵袭性双侧视网膜母细胞瘤），在有或没有当前标准护理治疗的情况下进行抗 PI3K 治疗的临床前测试。我们发现 FoxO 和 PI3K 活性有助于控制 E2F1 凋亡和增殖平衡，这表明这些研究将为正常细胞和癌细胞中这些蛋白质之间的机制关系提供重要的见解。该提案中概述的实验将提供有关 E2F1/FoxO 复合物的功能、其通过 PI3K 信号传导的调节以及体内抑制 PI3K 可能成为旨在恢复肿瘤中 E2F1/FoxO 细胞凋亡刺激的治疗选择的程度的重要信息。考虑到 Rb/E2F 和 PI3K/Pten 通路功能障碍在许多人类肿瘤中表现突出，我们预计我们的发现可能适用于其他肿瘤类型。