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: 7163755
• 负责人: ASTAR WINOTO
• 金额: $ 32.03万
• 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/7163755
• 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(申请人提供)：剖析如何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微妙平衡，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经得到了广泛的研究，但仍有几个主要问题有待回答。特别是，负选择的潜在途径尚不清楚，也不清楚为什么CD4+CD8+胸腺细胞对凋亡非常敏感。Nur77孤儿类固醇受体、Bcl-2促凋亡成员Bim、MAP激酶和PTEN肿瘤抑制因子都参与了负选择，但它们的作用机制和相互联系尚不清楚。MAP激酶在负选择中的作用也存在争议。对Nur77上游信号蛋白的研究表明，PTEN-PI3K-AKT通路是Nur77活性的调节者，而MEK5-ERK5激酶-级联通路是Nur77转录的激活剂。Nur77可以通过转录上调促凋亡分子FasL、TRAIL和新分子NDG1来启动细胞凋亡。然而，最近的一份报告显示，Nur77还可以与肿瘤细胞系线粒体中的Bcl2相互作用，将Bcl2转化为促凋亡分子。在这一应用中，我们提出了几个目的，旨在探索Nur77途径，并阐明胸腺细胞凋亡的机制。在目标1中，将通过建立T细胞特异性ERK5-/-小鼠和在胸腺器官培养中表达显性活性突变来研究ERK5 MAP激酶在T细胞发育中的作用。其他ERK5靶基因将被识别和分析。在目标2中，将使用转基因和基因敲除小鼠的方法来评估转录途径和线粒体途径在Nur77介导的细胞凋亡中的不同贡献。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AIM 3中通过检测过度表达细胞周期抑制物的转基因小鼠和分析T细胞特异性PTEN缺陷小鼠胸腺细胞中的PTEN下游靶基因来进行测试。这些目标的成功完成应该会导致对胸腺细胞如何进行凋亡以及肿瘤发生的重要理解。