PAC1 in Signaling Apoptosis and Tumor Suppression

PAC1 在信号凋亡和肿瘤抑制中的作用

基本信息

批准号：
7426827
负责人：
YUXIN YIN
金额：
$ 31.48万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-08-01 至 2010-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7426827
关键词：
Acetylation Achievement Address Animal Model Apoptosis Apoptotic Applications Grants Binding Cell Cycle Arrest Cell Cycle Regulation Cell Death Cell Survival Complement component C1s Condition DNA Repair Development E2F1 gene Gene Targeting Genes Genetic Transcription Genotoxic Stress Goals Grant Homologous Gene Human Lead Luciferases MAP Kinase Gene Malignant Neoplasms Mammalian Cell Mediating Mediator of activation protein Mitogen-Activated Protein Kinases Modification Molecular Mutation Normal Cell Numbers Oxidative Stress P1 Bacteriophage Artificial Chromosomes Pathway interactions Phosphoric Monoester Hydrolases Phosphorylation Play Post-Translational Protein Processing Predisposition Principal Investigator Protein Dephosphorylation Protein Overexpression Protein Tyrosine Phosphatase Regulation Reporter Reporting Role Series Signal Transduction Signal Transduction Pathway Stress Substrate Specificity System TP53 gene Testing Threonine Time Transcription Coactivator Transcriptional Regulation Tumor Suppression Tumor Suppressor Proteins Tumorigenicity Yin base cancer therapy cell growth cell injury cell suicide cisplatin/cyclophosphamide/doxorubicin protocol gene therapy inhibitor/antagonist irradiation mitogen-activated protein kinase phosphatase MKP6 paralogous gene programs promoter response transcription factor tumor tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): Transcription factors p53 and E2F-1 coordinate and mediate apoptosis in response to genotoxic stress. However, the mechanism whereby p53 and E2F-1 mediate apoptosis is unclear. We have recently reported that p53 is a direct transcriptional regulator of PAC1, a dual-specific threonine and tyrosine phosphatase with stringent substrate specificity for MAP kinase. We also found that E2F-1 regulates PAC1 at the transcriptional level. PAC1 has been shown as a potent inhibitor of MAP kinase activity through dephosphorylation of MAPK, In our p53 inducible system, PAC1 is greatly upregulated upon activation of p53 that leads to apoptosis. The expression of PAC1 in normal cells is significant increased following oxidative stress in a p53-dependent manner. We show that p53 binds to a palindromic motif in the PAC1 promoter and activates the PAC1 promoter, leading to the expression of PAC1. Importantly, PAC1 is induced only under the stress conditions that cause apoptosis but not the conditions that lead to cell cycle arrest, suggesting that p53 may be modified following apoptotic stresses. E2F-1 also stimulates the activity of the PAC1 promoter luciferase reporter. We further demonstrate that overexpression of E2F-1 elevates the levels of PAC1 transcription and that E2F-1 is required for full induction of PAC1 in response to oxidative stress. Finally, overexpression of PAC1 greatly increases cellular susceptibility to apoptosis. Our findings indicate that p53 and E2F-1 are transcriptional regulators of PAC1 and that PAC1 is a cell death mediator in the p53 and E2F-1 pathways. This is the first evidence that p53 and E2F-1 share a common target gene in signaling apoptosis. In this grant application, we propose a series of experimental approaches to demonstrate how p53 modifications influence its choice of binding to the palindromic motif and of selectively regulating PAC1. We will determine how PAC1 is regulated by E2F1. We will also determine whether and how p73, a p53 paralog tumor suppressor, regulates PAC1 and we will demonstrate the importance of PAC1 in tumorigenesis. Successful achievement of our specific aims will provide strong evidence for how p53, p73 and E2F-1 cooperatively regulate a dual-specific phosphatase that in turn inactivates MAP kinase, a signal transduction pathway for cell growth and proliferation. This grant may reveal a new target for gene therapy or lead to effective chemotherapeutical strategies in cancer treatment.

描述（由申请人提供）：转录因子P53和E2F-1响应遗传毒性应激，介导并介导凋亡。但是，p53和E2F-1介导凋亡的机制尚不清楚。我们最近报告说，p53是PAC1的直接转录调节剂，PAC1是一种双特异性苏氨酸和酪氨酸磷酸酶，对MAP激酶的底物特异性严格。我们还发现E2F-1在转录级别调节PAC1。 PAC1已通过MAPK的去磷酸化显示为MAP激酶活性的有效抑制剂，在我们的p53诱导系统中，PAC1在激活p53的激活后极大地上调，这会导致凋亡。氧化应激以p53依赖性方式在正常细胞中的PAC1表达显着增加。我们表明，p53与PAC1启动子中的全滴虫基序结合并激活PAC1启动子，从而导致PAC1的表达。重要的是，仅在引起凋亡的应力条件下诱导PAC1而不是导致细胞周期停滞的条件，这表明p53可以在凋亡应激后修饰。 E2F-1还刺激PAC1启动子荧光素酶报告基因的活性。我们进一步证明，E2F-1的过表达提高了PAC1转录水平，并且需要E2F-1才能完全诱导PAC1响应氧化应激。最后，PAC1的过表达大大增加了细胞对凋亡的敏感性。我们的发现表明，p53和E2F-1是PAC1的转录调节剂，PAC1是p53和E2F-1途径中的细胞死亡介质。这是p53和E2F-1在信号凋亡中具有共同靶基因的第一个证据。在此赠款应用中，我们提出了一系列实验方法，以证明p53修改如何影响其与alindromic基序的结合和选择性调节PAC1的选择。我们将确定如何通过E2F1调节PAC1。我们还将确定p73（p53旁系同源肿瘤抑制剂）是否调节PAC1的p73以及如何证明PAC1在肿瘤发生中的重要性。成功实现我们的特定目标将为p53，p73和e2f-1如何合作调节双特异性磷酸酶，这反过来又使MAP激酶（一种信号转导途径）灭活。该赠款可能揭示了基因治疗的新靶标或导致癌症治疗中有效的化学治疗策略。