HOMOLOGY- DEPENDENT DNA REPAIR, HYPOXIA, AND CANCER THERAPY

同源依赖性 DNA 修复、缺氧和癌症治疗

• 批准号: 7318304
• 负责人: PETER M GLAZER
• 金额: $ 28.43万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7318304
• 关键词: Affect; Alkylation; BRCA1 gene; BRCA2 gene; Base Excision Repairs; Binding; Biological Assay; Biotin; Breast; Cancer Biology; Cells; Co-Immunoprecipitations; Collaborations; Combined Modality Therapy; Complex; DNA Repair; Disruption; Double Strand Break Repair; Down-Regulation; E2F Transcription Factor 1; E2F1 gene; Equilibrium; Excision; Family; Gene Expression; Gene Targeting; Genetic; Genetic Recombination; Genetic Transcription; Genomics; Germ-Line Mutation; Goals; Guanine; Hereditary Breast and Ovarian Cancer Syndrome; Hypoxia; Lesion; Link; Malignant Neoplasms; Malignant neoplasm of ovary; Mass Spectrum Analysis; Mediating; Mutation; Non-Malignant; Nonhomologous DNA End Joining; O(6)-Methylguanine-DNA Methyltransferase; Pathway interactions; Pattern; Poly(ADP-ribose) Polymerases; Polymerase; Positioning Attribute; Post-Translational Protein Processing; Proteins; RBL2 gene; Regulation; Repression; Role; Series; Solid Neoplasm; Source; Stress; Testing; Therapeutic; Work; base; cancer cell; cancer site; cancer therapy; chromatin immunoprecipitation; crosslink; gene repair; human RBL2 protein; inhibitor/antagonist; insight; neoplastic cell; novel; novel strategies; novel therapeutics; promoter; recombinational repair; repaired; response; transcription factor; tumor; tumor progression

Genetic instability is a hallmark of cancer. We have shown in previous work that the hypoxic tumor microenvironment is one cause of this genetic instability, and we have recently found that hypoxia specifically causes decreased expression of the DMArepair factors, RAD51 and BRCA1. These factors maintain genomic integrity by mediating the repair of double-strand breaks and other lesions through the high-fidelity homology-dependent repair (HDR) pathway. Germline mutations in BRCA1 have been linked to hereditary breast and ovarian cancer, and decreased expression of BRCA1 has been seen in many sporadic cancers of these sites. In this project, we propose to investigate the mechanisms and consequences of RAD51 and BRCA1 regulation in response to hypoxia. We will examine key transcription regulatory mechanisms, with a focus on promoter repression by E2Fs and associated pocket proteins, and we will test the hypothesis that RAD51 and BRCA1 are coordinately regulated by these factors. The impact of decreased RAD51 and BRCA1 expression on genetic instability will be assessed using selected DNA recombination and repair assays to test the hypothesis that hypoxia-induced decreases in RAD51 and/or BRCA1 may shift the balance between the high-fidelity HDR and the error-prone non-homologous end-joining repair pathways. We will also test whether the suppression of HDR in hypoxic cells renders them especially vulnerable to novel therapeutic strategies, including inhibition of base excision repair (BER) (in collaboration with Project 3) by either poly(ADP-ribose) polymerase-1 (PARP-1) or polymerase beta inhibitors (to cause accumulation of unrepaired strand breaks) or inhibition of O6-alkylguanine-DNA alkyltransferase (AGT) in combination with agents that target the O-6 position of guanine and give rise to crosslinks (in collaboration with Project 1). These studies will provide further insight into how the hypoxic tumor microenvironment contributes to genetic instability and may offer an explanation for the down-regulation of BRCA1 detected in sporadic cancers. This work may also serve as a basis for novel therapeutic strategies to target hypoxic cells in solid tumors and possibly to treat familial breast and ovarian cancers associated with mutations in BRCA1 or BRCA2.

遗传不稳定性是癌症的一个标志。我们在之前的工作中已经证明，缺氧肿瘤 微环境是造成这种遗传不稳定的原因之一，我们最近发现缺氧 特别会导致 DMA 修复因子 RAD51 和 BRCA1 表达减少。这些因素 通过介导双链断裂和其他损伤的修复来维持基因组完整性 高保真同源依赖性修复（HDR）途径。 BRCA1 的种系突变与 遗传性乳腺癌和卵巢癌，在许多散发性癌症中都发现 BRCA1 表达下降 这些部位的癌症。 在这个项目中，我们建议研究 RAD51 和 BRCA1 的机制和后果 缺氧反应的调节。我们将研究关键的转录调控机制，重点是 E2F 和相关口袋蛋白对启动子的抑制，我们将检验 RAD51 的假设 和BRCA1受这些因素的协调调节。 RAD51 和 BRCA1 减少的影响 将使用选定的 DNA 重组和修复测定来评估遗传不稳定性的表达 检验以下假设：缺氧引起的 RAD51 和/或 BRCA1 减少可能会改变两者之间的平衡 高保真 HDR 和容易出错的非同源末端连接修复途径。我们也会测试 缺氧细胞中 HDR 的抑制是否使它们特别容易受到新疗法的影响 策略，包括抑制碱基切除修复 (BER)（与项目 3 合作） 聚（ADP-核糖）聚合酶-1 (PARP-1) 或聚合酶 β 抑制剂（导致 未修复的链断裂）或结合抑制 O6-烷基鸟嘌呤-DNA 烷基转移酶 (AGT) 针对鸟嘌呤 O-6 位并产生交联的试剂（与项目 1 合作）。 这些研究将进一步深入了解缺氧肿瘤微环境如何促进 遗传不稳定性，可能为散发性病例中检测到的 BRCA1 下调提供解释 癌症。这项工作也可以作为针对固体中缺氧细胞的新治疗策略的基础 肿瘤，并可能治疗与 BRCA1 或突变相关的家族性乳腺癌和卵巢癌 BRCA2。