Regulators of ubiquitin signaling in malignant hematopoiesis

恶性造血中泛素信号传导的调节因子

• 批准号: 10321308
• 负责人: Madeline Niederkorn
• 金额: $ 8.74万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10321308
• 关键词: AML/MDS; Acute Myelocytic Leukemia; Affect; Allogenic; Binding Proteins; Biochemical; Biological Assay; Biology; Cancer Biology; Case Study; Catalytic Domain; Cell Line; Cell physiology; Cells; Chemicals; Chromosome abnormality; Chromosomes; Clone Cells; Complex; DNA Damage; Data; Development; Disease; Disease Progression; Drug Targeting; Drug Utilization; Dysmyelopoietic Syndromes; Dysplasia; Event; Exhibits; FHA Domain; Familiarity; Family member; Foundations; Genes; Genetic study; Genotoxic Stress; Goals; Hematopoiesis; Hematopoietic Neoplasms; Hematopoietic stem cells; Human; Hypersensitivity; Immune; Immune signaling; Impairment; In Vitro; Individual; Investigation; MDM2 gene; MLL-AF9; Malignant - descriptor; Malignant Neoplasms; Modeling; Molecular; Mus; Myelogenous; Oncogenes; Oncogenic; Pathogenesis; Patients; Peptide Hydrolases; Phase; Phenotype; Positioning Attribute; Postdoctoral Fellow; Preleukemia; Prognosis; Proteomics; RUNX3 gene; Regulation; Reporting; Repression; Research; Research Personnel; Signal Transduction; Stem cell transplant; Stress; Structure; TP53 gene; TRAF-Interacting Protein; TRAF6 gene; Testing; Therapeutic; Toll-like receptors; Training; Ubiquitin; Work; Xenograft procedure; acute myeloid leukemia cell; base; chromosome 5q loss; curative treatments; cytopenia; drug development; drug discovery; druggable target; genotoxicity; high risk; in vivo; ineffective therapies; innate immune pathways; lead candidate; leukemia; leukemic transformation; member; mouse genetics; mouse model; novel; novel drug class; novel therapeutics; pressure; prevent; progenitor; programs; response; screening; small molecule inhibitor; stem cell function; stressor; therapeutic target; therapy development; transcriptome sequencing

Project Summary / Abstract Myelodysplastic syndromes (MDS) are heterogeneous clonal hematopoietic stem and progenitor cell (HSPC) disorders with frequent transformation to acute myeloid leukemia (AML). Molecular events leading to AML transformation are poorly defined and the only curative therapy is allogeneic stem cell transplantations, for which few patients are eligible. One of the reasons for ineffective treatments is the lack of understanding of the mechanisms of disease. Therefore, investigations into the cellular and molecular basis of genetically- defined MDS and AML subtypes are crucial to the development of novel therapies. Deletions on chromosome (chr) 5q (del5q) are the most frequent cytogenetic abnormality in MDS and are indicative of poor prognosis in AML. However, the functions of individual genes within del(5q) are largely unexplored. We recently reported that TRAF-interacting protein with forkhead-associated (FHA) domain B (TIFAB) is deleted in all reported cases of del(5q) MDS/AML and its deletion in mice results in phenotypes reminiscent of human MDS, due partly to aberrant innate immune signaling via TRAF6 activation; but, we also observed increases in p53 activity. To fully elucidate the mechanism of TIFAB-dependent regulation of p53, we performed a proteomics screen for TIFAB-binding proteins. Ubiquitin-specific peptidase 15 (USP15), a deubiquitinase that stabilizes MDM2 and enforces p53 degradation, emerged as the lead candidate. Therefore, we devised a multi-pronged approach in which we first, characterized the TIFAB-dependent p53 activity in our Tifab-deficient MDS model (Aim 1A), and second, uncovered the molecular mechanism of the TIFAB-USP15 complex in regulating p53 (Aim 1B). Our findings garnered rationale for defining the function of USP15 in established malignant hematopoiesis, which is well underway and which we propose to complete during the F99 phase of this research program (Aim 1C). Our preliminary data indicate that USP15 is highly expressed in AML and is important for leukemic progenitor function, but not normal HSPCs. We will employ a combination of in vivo and in vitro approaches using our Usp15-/- model, MLL-AF9 leukemia models, and AML cell lines to elucidate the function of USP15 in AML. In completing my dissertation research, I have acquired a strong foundation in mouse genetics, murine models, hematopoietic malignancies including MDS and AML, cancer biology, and cellular mechanisms. I have learned biochemical assays, structure-function studies, and genetic studies, while gaining familiarity with screening approaches including RNA-sequencing and proteomics. With my comprehensive training, I am positioned and highly motivated to pursue a post-doctoral research direction elucidating the determinants of USP15 activity, while utilizing drug discovery platforms to develop small- molecule inhibitors against this druggable target (Aim 2).

项目摘要 /摘要 骨髓增生综合征（MDS）是异质克隆造血茎和祖细胞（HSPC） 经常转化为急性髓样白血病（AML）的疾病。导致AML的分子事件 转化的定义很差，唯一的治疗疗法是同种异体干细胞移植，因为 哪些患者符合条件。无效治疗的原因之一是缺乏理解 疾病机制。因此，研究遗传学的细胞和分子基础 定义的MDS和AML亚型对于新型疗法的发展至关重要。染色体上的缺失 （chr）5q（del5q）是MDS中最常见的细胞遗传学异常，表明预后不良 AML。但是，在DEL（5Q）中单个基因的功能在很大程度上没有探索。我们最近报道 在所有报道的 DEL（5Q）MDS/AML及其在小鼠中的缺失的病例导致表型让人联想到人类MDS 通过TRAF6激活部分到异常的先天免疫信号传导；但是，我们还观察到p53的增加 活动。为了完全阐明p53的TIFAB依赖性调节机制，我们进行了蛋白质组学 筛选TIFAB结合蛋白。泛素特异性肽酶15（USP15），一种稳定的去泛素酶 MDM2并强制执行p53降解，成为主要候选人。因此，我们设计了一个多管齐下的 我们首先表征了TIFAB依赖性p53活性的方法 （AIM 1A），其次，发现了调节p53的TIFAB-USP15复合物的分子机制 （AIM 1B）。我们的发现获得了基本原理，以定义USP15在已建立的恶性中的功能 造血，这是良好的，我们建议在F99阶段完成 研究计划（AIM 1C）。我们的初步数据表明USP15在AML中高度表达，并且是 对于白血病祖细胞功能很重要，但不是正常的HSPC。我们将结合体内和 使用USP15 - / - 模型，MLL-AF9白血病模型和AML细胞系的体外方法来阐明 USP15在AML中的功能。在完成论文研究时，我为 小鼠遗传学，鼠模型，包括MDS和AML，癌症生物学以及 细胞机制。我学到了生化测定，结构功能研究和遗传研究，而 熟悉包括RNA测序和蛋白质组学在内的筛选方法。和我的 全面的培训，我的位置和高度动机去追求博士后研究方向 阐明USP15活性的决定因素，同时利用药物发现平台来发展小型 针对该毒靶标的分子抑制剂（AIM 2）。