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标志。我们在以前的工作中表明缺氧性肿瘤 微环境是这种遗传不稳定性的原因之一，我们最近发现缺氧 特异性导致DMAREPAIR因子RAD51和BRCA1的表达降低。这些因素 通过介导双链断裂和其他病变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中的种系突变已与 在许多零星 这些网站的癌症。 在这个项目中，我们建议研究RAD51和BRCA1的机制和后果 响应缺氧的调节。我们将检查关键转录调节机制，重点 E2F和相关的口袋蛋白抑制剂抑制剂，我们将测试RAD51的假设 和BRCA1受这些因素的协调调节。降低RAD51和BRCA1的影响 将使用选定的DNA重组和修复分析评估遗传不稳定性的表达 测试假设缺氧引起的RAD51和/或BRCA1的降低可能会改变 高保真HDR和容易出错的非同源最终连接修复途径。我们还将测试 缺氧细胞中HDR的抑制是否使它们特别容易受到新的治疗 策略，包括抑制基础切除修复（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（引起积累 未修复的链断裂）或抑制O6-烷基鸟嘌呤-DNA烷基转移酶（AGT） 针对鸟嘌呤位置并引起交联的代理（与项目1合作）。 这些研究将为低氧肿瘤微环境如何促进 遗传不稳定性，可能会为零星检测到的BRCA1下调提供解释 癌症。这项工作还可以作为靶向固体缺氧细胞的新型治疗策略的基础 肿瘤，可能治疗与BRCA1突变相关的家族性乳房和卵巢癌 BRCA2。