Plk3, A New Player In The Hypoxia Regulatory Networ.

Plk3，缺氧调节网络的新参与者。

基本信息

批准号：
8210839
负责人：
WEI DAI
金额：
$ 33.2万
依托单位：
NEW YORK UNIVERSITY SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-01-01 至 2015-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8210839
关键词：
Ablation Affect Alleles Animal Model Antineoplastic Agents Biochemical Cancer Biology Cell Death Coupled Cytokine-Inducible Kinase Defect Development Ectopic Expression Elderly Embryo Environmental Carcinogens Exposure to Fibroblasts Genes Genetic Genetic Transcription Goals Growth Factor Heterozygote Human Hypoxia In Vitro Knock-in Mouse Knockout Mice Knowledge Laboratories MAP Kinase Gene Malignant Neoplasms Mediating Metals Molecular Mus Neoplasm Metastasis Nickel Nuclear Nuclear Export Organ Oxygen PDPK1 gene PLK3 gene Phosphorylation Phosphorylation Site Phosphotransferases Physiological Play Polo-Box Domain Predisposition Prognostic Factor Proto-Oncogene Proteins c-akt Regulation Reporting Resistance Role Serine Signal Pathway Signal Transduction Signaling Molecule Site Somatotropin System Testing Treatment Failure Tumor Angiogenesis Vascularization base biological adaptation to stress cancer therapy cell growth drug development human PLK1 protein hypoxia inducible factor 1 in vivo mimetics mouse Cre recombinase mutant neoplastic cell nutrition overexpression public health relevance response toxicant tumor tumorigenesis

项目摘要

DESCRIPTION (provided by applicant): HIF-1 controls the transcription of many genes that are involved in key aspects of cancer biology. Overexpression of HIF-11, an inducible subunit of HIF-1 in response to hypoxia, is a prognostic factor in many cancers. The major signaling axis mediated by PI3K, PDK1, and Akt (also referred as protein kinase B) plays a significant role in the regulation of HIF-11 expression. Both GSK32 and MAPKs are also known to directly phosphorylate HIF-11, thereby affecting its stability and/or nuclear localization. To understand the regulatory network that suppresses tumor development and tumor angiogenesis, we have recently identified HIF-11 as a new in vitro substrate of Polo-like kinase 3 (Plk3). Plk3 strongly phosphorylates HIF-11 on serines 576 and 657 in vitro, two residues that lie in the oxygen-dependent degradation domain and near the nuclear export signal, respectively. By studying primary isogenic murine embryonic fibroblasts (MEFs), we have shown that PLK3-/- MEFs are hyper-sensitive to the induction of HIF-11 under hypoxia or treated with nickel, a hypoxia mimetic. Compared with that of wild- type MEFs, PLK3-/- MEFs contain a high level of Akt1/PKB activities, which is tightly associated with the inhibitory phosphorylation of GSK32. Consistent with the potential role of Plk3 in regulating the hypoxia signaling network, PLK3-/- mice develop tumors in various organs at an advanced age and PLK3-/- tumors are large in size and highly vascularized, suggesting active tumor angiogenesis. On the basis of these observations regarding physical and functional interactions between Plk3 and HIF-11, we hypothesize that Plk3 negatively regulates the hypoxia regulatory network and HIF-11-dependent tumor angiogenesis. To test the validity of this hypothesis, we will (i) study functional interaction between Plk3 and known signaling molecules, including GSK32 and MAPKs that phosphorylate HIF-11, and identify additional Plk3 target(s) upstream of Akt1, (ii) determine whether PLK3-/- mice are prone to tumorigenesis under hypoxia, and (iii) investigate whether mice harboring Plk3 phosphorylation-resistant mutant alleles of HIF-11 are more susceptible to tumorigenesis after nickel exposure. The combined in vitro and in vivo studies will greatly facilitate the elucidation of a new mechanism by which HIF-11 is regulated by Plk3 during hypoxic responses or after exposure to environmental carcinogens such as nickel compounds. A detailed understanding of the molecular regulation of HIF-11 will add significantly to the existing knowledge of tumor angiogenesis and tumor cell resistance to anti-cancer therapies. PUBLIC HEALTH RELEVANCE: Polo-like kinases function to regulate various aspects of cell growth and cell death. Our recent biochemical and mouse genetic studies show that Plk3 plays an important role in the regulation of the HIF- 11 signaling pathway, as well as in suppressing tumorigenesis. The major goal of this project is to elucidate what signaling pathways mediate Plk3 function in hypoxic stress responses and how genotoxic metal toxicants usurp cellular mechanisms that regulate HIF-11 during hypoxia.

描述（由申请人提供）：HIF-1 控制涉及癌症生物学关键方面的许多基因的转录。 HIF-11 是缺氧反应的 HIF-1 诱导亚基，其过度表达是许多癌症的预后因素。由 PI3K、PDK1 和 Akt（也称为蛋白激酶 B）介导的主要信号轴在 HIF-11 表达的调节中发挥着重要作用。已知 GSK32 和 MAPK 都会直接磷酸化 HIF-11，从而影响其稳定性和/或核定位。为了了解抑制肿瘤发展和肿瘤血管生成的调控网络，我们最近发现 HIF-11 是 Polo 样激酶 3 (Plk3) 的新体外底物。在体外，Plk3 在丝氨酸 576 和 657 上强烈磷酸化 HIF-11，这两个残基分别位于氧依赖性降解结构域和核输出信号附近。通过研究原代同基因小鼠胚胎成纤维细胞 (MEF)，我们发现 PLK3-/- MEF 在缺氧或用镍（一种缺氧模拟物）处理下对 HIF-11 的诱导高度敏感。与野生型 MEF 相比，PLK3-/- MEF 含有高水平的 Akt1/PKB 活性，这与 GSK32 的抑制性磷酸化密切相关。与 Plk3 在调节缺氧信号网络中的潜在作用一致，PLK3-/- 小鼠在高龄时会在多个器官中形成肿瘤，并且 PLK3-/- 肿瘤体积大且血管化程度高，表明肿瘤血管生成活跃。基于这些关于 Plk3 和 HIF-11 之间的物理和功能相互作用的观察，我们假设 Plk3 负向调节缺氧调节网络和 HIF-11 依赖性肿瘤血管生成。为了测试这一假设的有效性，我们将 (i) 研究 Plk3 与已知信号分子之间的功能相互作用，包括磷酸化 HIF-11 的 GSK32 和 MAPK，并确定 Akt1 上游的其他 Plk3 靶点，(ii) 确定是否PLK3-/-小鼠在缺氧下容易发生肿瘤，并且（iii）研究携带HIF-11的Plk3磷酸化抗性突变等位基因的小鼠是否更容易发生肿瘤镍暴露后。体外和体内联合研究将极大地促进阐明在缺氧反应期间或暴露于镍化合物等环境致癌物后 HIF-11 受 Plk3 调节的新机制。对 HIF-11 分子调控的详细了解将显着增加对肿瘤血管生成和肿瘤细胞抗癌治疗耐药性的现有了解。公共健康相关性：Polo 样激酶的功能是调节细胞生长和细胞死亡的各个方面。我们最近的生化和小鼠遗传学研究表明，Plk3 在 HIF-11 信号通路的调节以及抑制肿瘤发生中发挥着重要作用。该项目的主要目标是阐明哪些信号通路在缺氧应激反应中介导 Plk3 功能，以及基因毒性金属毒物如何篡夺缺氧期间调节 HIF-11 的细胞机制。