Examine the function of APOBEC3B in epithelial ovarian cancer stem cells

检查 APOBEC3B 在上皮性卵巢癌干细胞中的功能

• 批准号: 10580076
• 负责人: Qingfei Jiang
• 金额: $ 7.9万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10580076
• 关键词: Adoption; Apoptosis; Area; Cancer Patient; Cancer Relapse; Cell Cycle; Cell Cycle Arrest; Cell Cycle Regulation; Cell Maintenance; Cells; Chromosome abnormality; Combined Modality Therapy; Cytidine; DNA; DNA Damage; DNA Double Strand Break; DNA Modification Process; DNA Repair; DNA Sequence Alteration; DNA Single Strand Break; Data; Deaminase; Deamination; Development; Diagnosis; Disease; Drug resistance; Enzymes; Epithelial ovarian cancer; Family; Frequencies; Goals; Induced Mutation; Inherited; Innate Immune Response; L1 Elements; Lead; Maintenance Therapy; Malignant Female Reproductive System Neoplasm; Malignant Neoplasms; Malignant neoplasm of ovary; Medical; Mission; Modeling; Molecular; Monitor; Mutation; Neoplasm Metastasis; Organism; Organoids; Pathway interactions; Patients; Phase; Play; Point Mutation; Poly(ADP-ribose) Polymerase Inhibitor; Population; Prevalence; Primary Neoplasm; Progression-Free Survivals; Proteins; Recurrence; Recurrent disease; Research; Resistance; Resistance development; Role; Single-Stranded DNA; Source; Survival Rate; Testing; Treatment Efficacy; United States National Institutes of Health; Uridine; Viral; Virus Replication; Work; apolipoprotein B mRNA editing enzyme; brca gene; cancer stem cell; cancer type; chemotherapy; drug resistance development; effective therapy; gene repair; improved; inhibitor; innovation; insight; mutant; new therapeutic target; novel; novel therapeutics; overexpression; particle; patient subsets; polypeptide; prevent; rare cancer; response; self-renewal; stem cell biology; stem cell function; stem cells; stemness; synergism; therapy resistant; tumor; tumor growth

SUMMARY/ABSTRACT Ovarian cancer is the most lethal gynecologic malignancy and is frequently diagnosed at an advanced-stage. One of the most aggressive types of ovarian cancer is epithelial ovarian cancer (EOC) and 5-year survival is less than 20%. In recent years, PARP inhibitors (PARPi) has shown impressive therapeutic efficacy as both maintenance therapy and in recurrent setting. However, since the wide application of PARPi, patients ultimately develop drug resistance to PARPi which leaves them with few treatment options. Thus, the development of novel therapies to overcome PAPRi resistance represents an urgent unmet medical need. The PARPi-resistant patients often have enriched cancer stem cells (CSCs) with enhanced pro-survival and self-renewal capacity. Evidence demonstrations that EOC CSCs are responsible for primary tumor growth, metastasis, disease relapse and resistance to chemotherapy, suggesting CSC is an attractive target for eradicating EOC. Our long-term goal is to identify new targets for development of less toxic and more effective therapies by eliminating this cell population. Apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3 (APOBEC3) proteins are a family of DNA deaminase that catalyze cytidine to uridine (C-to-U) on single-strand DNA. This important DNA modification is abundant in a wide array of cancer types and represent the only enzymatic source of mutations. We discovered that APOBEC3B (A3B) is the main DNA mutators in EOC CSC. The C-to-U DNA mutation activity and A3B expression is reduced in EOC CSCs compared to non-CSCs. Importantly, inhibition of A3B leads to PARPi resistance, elevated frequency of CSCs, and enhanced expression of stemness factor SOX2. These novel insights raise the possibility that A3B activation may sensitize EOC CSCs to PARPi. Our central hypothesis is that EOC CSCs maintain low level of A3B in order to avoid excess DNA damage thereby counters the effect of PARPi. The overall goal of this study is to dissect the mechanism through which A3B and DNA deamination regulates CSC maintenance and promote response to PARPi in EOC CSC. We will address our hypothesis in two specific aims: 1) Determine if modified A3B activity will sensitize CSCs to combination therapy with PARPi, 2) Identify the novel mechanisms by which A3B regulates response to PARP inhibitor in EOC CSCs. We will perform A3B overexpression studies in patient-derived organoid models and comprehensively evaluate changes in EOC CSC functions and the response to PARPi. Mechanistically, we will assess DNA damage pathways, chromosomal abnormalities, and ssDNA break levels in CSCs that overexpress A3B alone and in combination treatment with PARPi. In addition, the molecular mechanism of how A3B regulates CSC’s response to PARPi will also be examined. This innovative study will improve our understanding of how A3B sensitize EOC CSCs to PARPi by promoting DNA damage and uncover valuable novel therapeutic targets to preventing ovarian cancer relapse. These mechanisms may be broadly applicable to other CSC-driven malignancies.

摘要/摘要 卵巢癌是最致命的妇科恶性肿瘤，经常在晚期被诊断出。 卵巢癌最具侵略性的类型之一是上皮卵巢癌（EOC），5年生存率较小 超过20％。近年来，PARP抑制剂（PARPI）表现出令人印象深刻的治疗效率 维护疗法和经常性环境。但是，由于PARPI的广泛应用，患者最终 发展对PARPI的耐药性，这使他们几乎没有治疗选择。那，小说的发展 克服帕普里抗性的疗法是紧迫的未满足医疗需求。抗parpi 患者经常具有增强的促生存和自我更新能力的富集癌症干细胞（CSC）。 证据表明EOC CSC负责原发性肿瘤生长，转移，疾病缓解 对化学疗法的耐药性，表明CSC是消除EOC的有吸引力的目标。我们的长期目标 是通过消除该细胞来确定开发毒性较小和更有效疗法的新目标 人口。载脂蛋白B mRNA编辑酶催化多肽样3（APOBEC3）蛋白是一个家族 单链DNA上将胞苷催化为尿苷（C-TO-U）的DNA脱氨酶这个重要的DNA 在多种癌症类型中，修饰很丰富，代表了突变的唯一酶促来源。 我们发现APOBEC3B（A3B）是EOC CSC中的主要DNA突变器。 C-TO-U DNA突变活性 与非CSC相比，EOC CSC中的A3b表达降低。重要的是，抑制A3B导致 PARPI抗性，CSC的频率升高以及Stemness因子SOX2的表达增强。这些 新颖的见解提出了A3B激活可能会使PARPI感知EOC CSC的可能性。我们的中心假设 是，EOC CSC维持低水平的A3B以避免超过DNA损伤，从而抵消了效果 Parpi。这项研究的总体目标是剖析A3B和DNA死亡的机制 调节CSC维护并促进EOC CSC中对PARPI的反应。我们将解决我们的假设 两个具体的目的：1）确定修改的A3B活动是否会感知CSC与PARPI组合疗法， 2）确定A3B调节EOC CSC中对PARP抑制剂的反应的新机制。我们将 在患者衍生的器官模型中进行A3B过表达研究，并全面评估变化 在EOC CSC函数和对PARPI的响应中。从机械上讲，我们将评估DNA损伤途径， 染色体异常和单独表达A3b和组合过表达A3B的CSC中的ssDNA断裂水平 用parpi治疗。另外，A3B如何调节CSC对PARPI的反应的分子机制 也将被检查。这项创新的研究将提高我们对A3B敏感性EOC CSC的理解 通过促进DNA损伤并发现有价值的新型治疗靶标，以防止卵巢癌 复发。这些机制可能广泛适用于其他CSC驱动的恶性肿瘤。