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: 10438420
• 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/10438420
• 关键词: Address; 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; 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; 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; 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，并且经常在晚期被诊断出来。 上皮性卵巢癌 (EOC) 是最具侵袭性的卵巢癌类型之一，其 5 年生存率较低 超过20%。近年来，PARP抑制剂（PARPi）显示出令人印象深刻的治疗效果，因为 维持治疗和复发情况。然而，随着PARPi的广泛应用，患者最终 对 PARPi 产生耐药性，这使得他们几乎没有治疗选择。于是，小说的发展 克服 PAPRi 耐药性的疗法代表了迫切的未满足的医疗需求。 PARPi 抗性 患者通常具有丰富的癌症干细胞（CSC），具有增强的促生存和自我更新能力。 有证据表明 EOC CSC 与原发性肿瘤生长、转移和疾病复发有关 和对化疗的耐药性，表明 CSC 是根除 EOC 的一个有吸引力的目标。我们的长期目标 是通过消除这种细胞来确定新的靶标，以开发毒性更小、更有效的疗法 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 DNA 脱氨酶催化单链 D​​NA 上的胞苷转化为尿苷（C-to-U）。这个重要的DNA 修饰在多种癌症类型中大量存在，并且是突变的唯一酶促来源。 我们发现 APOBEC3B (A3B) 是 EOC CSC 中的主要 DNA 突变基因。 C-to-U DNA 突变活性 与非 CSC 相比，EOC CSC 中 A3B 表达降低。重要的是，抑制 A3B 会导致 PARPi 耐药性、CSC 频率升高以及干性因子 SOX2 表达增强。这些 新的见解提出了 A3B 激活可能使 EOC CSC 对 PARPi 敏感的可能性。我们的中心假设 EOC CSCs 维持低水平的 A3B 以避免过度的 DNA 损伤，从而抵消这种影响 PARPi。本研究的总体目标是剖析 A3B 和 DNA 脱氨基作用的机制 调节 CSC 维护并促进 EOC CSC 中 PARPi 的反应。我们将在 两个具体目标：1) 确定修饰的 A3B 活性是否会使 CSC 对 PARPi 联合治疗敏感， 2) 确定 A3B 调节 EOC CSC 中 PARP 抑制剂反应的新机制。我们将 在患者来源的类器官模型中进行 A3B 过度表达研究并综合评估变化 EOC CSC 功能和对 PARPi 的响应。从机制上讲，我们将评估 DNA 损伤途径， 单独和组合过度表达 A3B 的 CSC 中的染色体异常和 ssDNA 断裂水平 用 PARPi 治疗。此外，A3B如何调节CSC对PARPi反应的分子机制 也将受到审查。这项创新研究将加深我们对 A3B 如何使 EOC CSC 敏感的理解 PARPi 通过促进 DNA 损伤并发现有价值的新治疗靶点来预防卵巢癌 复发。这些机制可能广泛适用于其他 CSC 驱动的恶性肿瘤。