Mechanisms Underlying Replication Stress And Genome Instability Upon BRCA2 Deficiency

BRCA2 缺陷引起的复制压力和基因组不稳定的潜在机制

• 批准号: 10504242
• 负责人: Shailja Pathania
• 金额: $ 34.88万
• 依托单位: UNIVERSITY OF MASSACHUSETTS BOSTON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2027-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10504242
• 关键词: Address; Affect; Applications Grants; Automobile Driving; BRCA2 Mutation; BRCA2 gene; Biological Markers; Breast Cancer Risk Factor; Cells; Chemoresistance; Climacteric; Combination Drug Therapy; Cytosine; Cytosine deaminase; DNA; DNA Damage; DNA Sequence Alteration; DNA replication fork; Data; Deaminase; Deamination; Defect; Down-Regulation; Enzymes; Event; Family; Genome; Genome Stability; Genomic Instability; Genomics; Germ-Line Mutation; Goals; Incidence; Individual; Knowledge; Lead; Learning; Location; Malignant Neoplasms; Malignant neoplasm of ovary; Malignant neoplasm of prostate; Mammary Gland Parenchyma; Molecular; Normal Cell; Nucleotide Excision Repair; Operative Surgical Procedures; Ovarian Tissue; Pancreas; Pathogenicity; Pathway interactions; Patients; Pharmaceutical Preparations; Prevention strategy; Process; Prostate; Publishing; Risk; Role; Single-Stranded DNA; Site; Somatic Mutation; Source; Testing; Therapeutic; Time; Tissues; Treatment Efficacy; Uracil; Woman; Work; Xenograft Model; base; cancer prevention; chemotherapy; design; efficacy evaluation; exhaustion; experimental study; high risk; insight; lifetime risk; malignant breast neoplasm; mutant; mutation carrier; neoplastic cell; novel; novel therapeutic intervention; potential biomarker; prophylactic; repaired; replication factor A; replication stress; tool; tumor; tumorigenesis; variant of unknown significance

PROJECT SUMMARY BRCA2 mutation carriers are highly predisposed to breast and ovarian cancer (60% risk for breast cancer and 30-40% for ovarian cancer), and also have increased risk for other cancers like prostate and pancreatic. However, the mechanisms underlying these phenomena are still poorly understood. The molecular pathogenic steps, especially the earliest ones that drive the transition of normal cells (BRCA2mut/+) in a BRCA2 mutation carrier to tumor cells are largely unknown. Experiments detailed in this proposal will provide valuable clues to what those early steps could be. The knowledge and understanding of the way a normal, presumably healthy cell in BRCA2 mutation carrying individual starts becoming a tumor cell, will give us a much-needed early advantage to help design preventive strategies and contribute towards decreasing B2 mutant cancer incidence. The experimental strategy described in this proposal is based on our recently published work that shows increased single stranded DNA (ssDNA) accumulation in BRCA2 deficient cells, and on our preliminary data that shows high abasic site and uracil accumulation in BRCA2 deficient cells. Our preliminary data also shows defective nucleotide excision repair (NER) pathway in BRCA2 deficient cells. Based on our strong preliminary data, we propose to study the role of APOBEC/AID family of cytosine deaminases in generating abasic sites in BRCA2 deficient cells. We will also use BRCA2 patient derived tissue to design new ways to classify variants of unknown significance and also learn how increased abasic site and uracil in B2 heterozygous cells could contribute to genomic instability and tumorigenesis. Finally, we will also study whether BRCA2 deficient cells are defective in NER when undergoing replication stress, and if this weakness in BRCA2 mutant tumors could be targeted by combination drug therapy. This study provides an opportunity to address the question of early DNA damaging events that drive BRCA2 mutant tumorigenesis, and has the potential to provide the much needed, critical information that will help with the design of effective cancer prevention and therapeutic strategies for BRCA2 mutation bearing women.

项目摘要 BRCA 2突变携带者极易患乳腺癌和卵巢癌（60%的乳腺癌风险， 30-40%的卵巢癌），也增加了患前列腺癌和胰腺癌等其他癌症的风险。 然而，这些现象背后的机制仍然知之甚少。分子致病性 步骤，特别是在BRCA 2突变中驱动正常细胞（BRCA 2 mut/+）转变的最早步骤 携带者对肿瘤细胞的作用在很大程度上是未知的。本提案中详细介绍的实验将为以下方面提供有价值的线索： 这些早期的步骤可能是什么。知识和理解的方式一个正常的，大概是健康的 携带BRCA 2突变的个体中的细胞开始成为肿瘤细胞，将给我们一个急需的早期 这一优势有助于设计预防策略，并有助于降低B2突变型癌症的发病率。 本提案中描述的实验策略是基于我们最近发表的工作， BRCA 2缺陷细胞中单链DNA（ssDNA）积累增加，根据我们的初步数据， 显示BRCA 2缺陷细胞中的高脱碱基位点和尿嘧啶积累。我们的初步数据还显示 BRCA 2缺陷细胞中的核苷酸切除修复（NER）途径缺陷。根据我们初步的证据 数据，我们建议研究胞嘧啶脱氨酶的APOBEC/AID家族在产生脱碱基位点中的作用， BRCA 2缺陷细胞。我们还将使用BRCA 2患者来源的组织来设计新的方法来分类BRCA 2的变体。 未知的意义，并了解如何增加无碱基位点和尿嘧啶在B2杂合子细胞， 导致基因组不稳定和肿瘤发生。最后，我们还将研究BRCA 2缺陷细胞是否 在经历复制应激时，NER有缺陷，如果BRCA 2突变肿瘤中的这种弱点可能是 通过联合药物治疗靶向。 这项研究提供了一个机会来解决早期DNA损伤事件的问题， BRCA 2突变肿瘤发生，并有可能提供急需的，关键的信息， 帮助设计有效的癌症预防和BRCA 2突变携带者的治疗策略 妇女