Programmed Cell death in Normal and Malignant T cells

正常和恶性 T 细胞的程序性细胞死亡

• 批准号: 7336324
• 负责人: ASTAR WINOTO
• 金额: $ 31.99万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-12-08 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7336324
• 关键词: Affinity Chromatography; Alleles; Apoptosis; Apoptotic; Binding; Biological Models; Biology; CDK6-associated protein p18; CDKN1A gene; Cell Cycle; Cell Cycle Progression; Cell Maturation; Cell Proliferation; Cell Survival; Cells; Chimeric Proteins; DNA Binding Domain; Data; Dominant-Negative Mutation; Embryo; Equilibrium; Family; Fibroblasts; Gene Targeting; Genes; Genetic Transcription; In Vitro; Knockout Mice; Lead; Literature; MAPK7 gene; MAPK7 gene; Malignant - descriptor; Mediating; Microarray Analysis; Mitochondria; Mitogen-Activated Protein Kinases; Molecular; Molecular Probes; Mus; Organ Culture Techniques; Orphan; PTEN gene; Pathway interactions; Peripheral; Phosphoric Monoester Hydrolases; Process; Proteins; Publishing; Reporting; Research Personnel; Retroviridae; Role; Signal Pathway; Signaling Protein; Small Interfering RNA; Steroid Receptors; System; T-Cell Development; T-Lymphocyte; TNFSF10 gene; Techniques; Testing; Transactivation; Transcriptional Activation; Transgenic Mice; Transgenic Organisms; Tumor Cell Line; Tumor Suppressor Proteins; Up-Regulation; angiogenesis; base; caspase-8; design; human prostaglandin D2 receptor; in vivo; inhibitor/antagonist; member; mutant; neoplastic cell; novel; oncoprotein p21; programs; promoter; thymocyte; transcription factor; tumorigenesis

DESCRIPTION (provided by applicant): Dissecting the molecular mechanisms of how proliferation and apoptosis are controlled is the key to understanding tumorigenesis. T cell development involves a fine balance of apoptosis and cell proliferation and is thus an ideal system to probe the molecular mechanisms of these two fundamental processes. Many aspects of T cell development have been studied extensively but several major questions remain to be answered. In particular, pathways underlying negative selection are yet to be elucidated and it is still not clear why CD4+CD8+ thymocytes are exquisitely sensitive to apoptosis. Nur77 orphan steroid receptor, the Bcl-2 pro-apoptotic member Bim, MAP kinases and PTEN tumor suppressor have all been implicated in negative selection but their mechanisms of action and inter-connection remain unclear. The role of MAP kinases in negative selection is also controversial. Studies of Nur77 upstream signaling proteins have shown PTEN-PI3kinase-AKT pathway as a modulator of Nur77 activity and MEK5-ERK5 kinase-cascade as an activator of Nur77 transcription. Nur77 can initiate apoptosis by transcriptional up-regulation of pro-apoptotic molecules FasL, TRAIL and NDG1, a novel molecule. However, a recent report showed that Nur77 could also interact with Bcl-2 in mitochondria of tumor cell lines and convert Bcl-2 into a pro-apoptotic molecule. In this application, we propose several aims designed to probe the Nur77 pathway and to elucidate the mechanism of thymocyte apoptosis. In aim 1, the role of ERK5 MAP kinase in T cell development will be examined by generating T-cell specific ERK5-/- mice and by expressing dominant active mutants in thymic organ culture. Additional ERK5 target genes will be identified and analyzed. In aim 2, the differential contribution of transcriptional versus mitochondria pathway in Nur77-mediated apoptosis will be assessed using transgenic and knockout mouse approach. We propose that apoptosis of CD4+CD8+ thymocytes is dependent on activation of the cell cycle machinery. This will be tested in aim 3 by examining transgenic mice over-expressing cell cycle inhibitors and by analyzing PTEN downstream target genes in thymocytes of T cell-specific PTEN-deficient mice. Successful completion of these aims should lead to a significant understanding of how apoptosis proceeds in thymocytes and how tumorigenesis might arise.

描述（由申请人提供）：剖析控制增殖和凋亡的分子机制是理解肿瘤发生的关键。 T 细胞发育涉及细胞凋亡和细胞增殖的良好平衡，因此是探索这两个基本过程的分子机制的理想系统。 T 细胞发育的许多方面已得到广泛研究，但几个主要问题仍有待解答。特别是，负选择的途径尚未阐明，并且仍不清楚为什么 CD4+CD8+ 胸腺细胞对细胞凋亡极其敏感。 Nur77 孤儿类固醇受体、Bcl-2 促凋亡成员 Bim、MAP 激酶和 PTEN 肿瘤抑制因子都与负选择有关，但它们的作用机制和相互关系仍不清楚。 MAP 激酶在阴性选择中的作用也存在争议。 Nur77 上游信号蛋白的研究表明，PTEN-PI3kinase-AKT 通路是 Nur77 活性的调节剂，而 MEK5-ERK5 激酶级联是 Nur77 转录的激活剂。 Nur77 可以通过促凋亡分子 FasL、TRAIL 和新分子 NDG1 的转录上调来启动细胞凋亡。然而，最近的一份报告表明，Nur77还可以与肿瘤细胞系线粒体中的Bcl-2相互作用，并将Bcl-2转化为促凋亡分子。在本申请中，我们提出了几个旨在探测 Nur77 通路并阐明胸腺细胞凋亡机制的目标。在目标 1 中，将通过生成 T 细胞特异性 ERK5-/- 小鼠并在胸腺器官培养物中表达显性活性突变体来检查 ERK5 MAP 激酶在 T 细胞发育中的作用。其他 ERK5 靶基因将被鉴定和分析。在目标 2 中，将使用转基因和敲除小鼠方法评估转录途径与线粒体途径在 Nur77 介导的细胞凋亡中的差异贡献。我们认为 CD4+CD8+ 胸腺细胞的凋亡依赖于细胞周期机制的激活。这将在目标 3 中进行测试，方法是检查转基因小鼠过度表达细胞周期抑制剂，并分析 T 细胞特异性 PTEN 缺陷小鼠胸腺细胞中的 PTEN 下游靶基因。成功完成这些目标应该有助于人们对胸腺细胞凋亡如何进行以及肿瘤发生如何发生有重要的了解。