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，常在晚期确诊。 卵巢癌中最具侵袭性的类型之一是上皮性卵巢癌(EOC)，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 维持治疗和复发期。然而，由于PARPI的广泛应用，患者最终 对PARPI产生抗药性，这让他们几乎没有治疗选择。因此，小说的发展 克服纸巾耐药性的疗法代表着一种紧急的、未得到满足的医疗需求。抗PARPI的 患者通常拥有丰富的肿瘤干细胞(CSCs)，具有增强的促生存和自我更新能力。 证据表明，EoC CSCs与原发肿瘤的生长、转移和疾病复发有关 化疗耐药，提示CSC是根除EOC的有吸引力的靶点。我们的长期目标 是通过消除这种细胞来确定开发毒性更低、更有效的治疗方法的新靶点 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 在单链DNA上催化胞苷生成尿苷(C-to-U)的DNA脱氨酶。这种重要的DNA 修饰在广泛的癌症类型中大量存在，是唯一的突变酶来源。 我们发现APOBEC3B(A3B)是EoC CSC的主要DNA突变子。C-U DNA突变活性的研究 与非CSCs相比，EoC CSCs中A3B的表达降低。重要的是，抑制A3B会导致 PARPI抗性，CSCs频率升高，茎因子SOX2表达增强。这些 新的见解提出了A3B激活可能使EoC CSCs对PARPI敏感的可能性。我们的中心假设 EoC CSCs维持较低的A3B水平，以避免过度的DNA损伤，从而抵消其影响 帕尔皮的。这项研究的总体目标是剖析A3B和DNA脱氨的机制 在EoC CSC中规范CSC的维护并促进对PARPI的响应。我们将在中讨论我们的假设 两个具体目标：1)确定修饰的A3B活性是否会使CSCs对PARPI联合治疗敏感， 2)明确A3B调节EoC CSCs对PARP抑制剂反应的新机制。我们会 在患者衍生的器官模型中进行A3B过度表达研究，并综合评估变化 在EoC中，CSC的职能和对PARPI的回应。从机制上讲，我们将评估DNA损伤途径， 单独和联合过表达A3B的CSCs的染色体异常和单链DNA断裂水平 用PARPI治疗。此外，A3B调节CSC对PARPI反应的分子机制 还将接受检查。这项创新的研究将提高我们对A3B如何使EoC CSCs敏感的理解 PARPI通过促进DNA损伤和发现有价值的新治疗靶点预防卵巢癌 旧病复发。这些机制可能广泛适用于其他由CSC驱动的恶性肿瘤。