Effectors of p53 Pro-survival and Pro-apoptotic Signaling Pathways

众所周知，P53是基因组的守护者，因为它能够激活细胞周期停滞或 对DNA损伤作出反应的细胞凋亡。该项目发现了P53细胞应激反应在 通过转录上调I型干扰素的核心成分IRF9增强天然免疫 (干扰素)反应。来自我们的研究和其他研究的最新证据表明，P53还直接上调了几个 在先天性免疫中发挥重要作用的靶基因，包括Toll样受体(TLRs)，IFN调节 因子(IRF)、干扰素刺激基因(ISGs)和肿瘤坏死因子-α(TNF-a)。在这个范围内 项目期间，我们发现了一个新的P53靶基因CDIP(细胞死亡涉及P53靶基因)，它显著地 上调P53依赖的肿瘤坏死因子-α的表达，促进肿瘤坏死因子-α的凋亡而不是存活细胞的命运 决定。我们计划继续我们的研究，解决这些在p53生物学中的新方向。目标1 建议调查这些新发现的P53依赖表达的贡献 先天抗病毒免疫反应的靶基因，包括该反应的miRNA成分，经鉴定 我们也要发挥作用。我们将通过项目2和项目3探索我们的发现，即I型干扰素可以增强蛋白质。 水平通过非转录机制以及涉及的翻译后修饰。我们还将 确定MDM2抑制剂在蛋白质水平上增加P53以增强P53依赖的能力 体内和体外的先天抗病毒反应。在目标2中，我们将调查CDIP执行的机制 肿瘤坏死因子-α诱导肿瘤细胞存活过程中的凋亡及其在肿瘤细胞生长抑制中的作用我们 还将利用串联亲和纯化策略来鉴定CDIP相互作用蛋白并与 项目2解决了该分子的新结构。我们有证据证明生成CDIP的可行性 应该有助于阐明CDIP组织表达和任何发育障碍的基因敲除小鼠 与发育功能丧失以及CDIP功能丧失对化疗/放疗和肿瘤坏死因子-a的影响 敏感度。在目标3中，我们计划整合这些研究，以阐明p53是如何先天免疫的。 在化学致癌模型中，细胞因子信号转导功能影响肿瘤发生 已知内源性干扰素和肿瘤坏死因子-α可抑制肿瘤的形成。MDM2小分子拮抗剂将 应用于剖析P53抑癌基因在肿瘤发生发展中的作用。这些调查将是 通过持续的每月会议和由经验丰富的调查人员参与的协作互动提供帮助 他们每个人都专注于研究P53调控和效应器的新方面。

p53 is widely known as 'the guardian of the genome' due to its ability to activate either cell cycle arrest or apoptosis in response to DNA damage. This project has uncovered a novel role of p53 cell stress responses in enforcing innate immunity by transcriptional upregulation of IRF9, a central component of the type I interferon (IFN) response. Recent evidence from our studies and others indicates that p53 also directly upregulates several target genes in pathways that play a major role in innate immunity including toll-like receptors (TLRs), IFNregulatory factors (IRFs), IFN-stimulated genes (ISGs) and tumor necrosis factor alpha (TNF-a). Within this project, we discovered a novel p53 target gene, CDIP (Cell Death Involved p53 target), which markedly upregulates p53 dependent expression of TNF-a, and promotes TNF-a apoptosis over survival cell fate decisions. We plan to continue our investigations addressing these novel directions in p53 biology. Aim 1 of this proposal is directed toward investigating the contribution of p53 dependent expression of these newly identified target genes to the innate antiviral immune response including a miRNA component of this response identified by us to play a role as well. We will explore with Projects 2 and 3, our findings that type I IFNs enhance protein levels by a non-transcriptional mechanism as well as the posttranslational modifications involved. We will also determine the ability of MDM2 inhibitors, which increase p53 at the protein level to enhance p53-dependent innate antiviral responses in vitro and in vivo. In Aim 2 we will investigate mechanisms by which CDIP enforces TNF-a induced apoptosis over survival and its specific role in TNF-a growth inhibition of human tumor cells. We will also utilize a tandem affinity purification strategy to identify CDIP Interacting proteins and collaborate with Project 2 to solve the novel structure of this molecule. We have evidence for feasibility of generating a CDIP knockout mouse that should help to elucidate CDIP tissue expression and any developmental perturbations due to loss of function on development, as well as how loss of CDIP function affects chemo/irradiation and TNF-a sensitivity. In Aim 3, we plan to integrate these investigations toward elucidating how p53 innate immune functions through cytokine signaling impact tumorigenesis in chemical carcinogenesis models in which endogenous IFNs and TNF-a are known to inhibit tumor formation. MDM2 small molecule antagonists will be applied to dissect p53 tumor suppressor functions in tumor initiation and progression. These investigations will be aided by continuing monthly meetings and collaborative interactions involving experienced investigators within the Program, each of whom is focused on studying novel aspects of p53 regulation and effectors.