Identifying Conserved Genetic Networks for Eukaryotic MMR Genes

鉴定真核 MMR 基因的保守遗传网络

• 批准号: 8095502
• 负责人: WINFRIED EDELMANN
• 金额: $ 20.75万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8095502
• 关键词: Acute Myelocytic Leukemia; Animal Model; Antineoplastic Agents; Apoptosis; Base Pair Mismatch; Biological Assay; Cancer Patient; Cancer cell line; Cell Culture Techniques; Cell Cycle; Cell Cycle Arrest; Cell Line; Cell Survival; Cells; Characteristics; Chemical Agents; Chemosensitization; Cisplatin; Colorectal; Colorectal Cancer; Complex; DNA; DNA Damage; DNA damage checkpoint; Data; Data Analyses; Data Set; Databases; Defect; Development; Disease; Drug Combinations; Dysmyelopoietic Syndromes; Environmental Exposure; Escherichia coli; Eukaryota; Excision; Exposure to; Fission Yeast; Fluorouracil; Genes; Genetic; Genetic Recombination; Genome; Genome Stability; Genomics; Goals; Hematopoietic; Hereditary Nonpolyposis Colorectal Neoplasms; Homologous Gene; Human; Image Analysis; Individual; Knock-out; MLH1 gene; MSH2 gene; MSH3 gene; MSH6 gene; Malignant Neoplasms; Mammalian Cell; Mammals; Measures; Mediating; Microsatellite Instability; Mismatch Repair; Modeling; Molecular; Mouse Cell Line; Mus; Mutagens; Mutation; Orthologous Gene; Outcome; PMS2 gene; Pathway interactions; Pharmaceutical Preparations; Play; Prokaryotic Cells; Proliferating; Proteins; Repair Complex; Replication Error; Research; Resistance; Role; Saccharomyces cerevisiae; Saccharomycetales; Second Primary Cancers; Signal Transduction; Small Interfering RNA; Syndrome; System; Testing; Therapeutic; Xenograft Model; Yeasts; base; cell growth; chemotherapeutic agent; chemotherapy; embryonic stem cell; fitness; interest; leukemia; mammalian genome; mutant; novel; novel therapeutics; precursor cell; prevent; repaired; response; small hairpin RNA; tumor; tumorigenesis

DESCRIPTION (provided by applicant): DNA mismatch repair (MMR) is a conserved repair pathway and is essential for maintaining genomic integrity in prokaryotes and eukaryotes. MMR has been the focus of intensive research efforts because mutations in MMR genes are the underlying cause of Lynch syndrome (HNPCC, hereditary nonpolyposis colorectal cancer) and a significant proportion of sporadic colorectal cancers. The majority of these cancer cases are caused by mutations in the human homologs of the E. Coli mutS and mutL genes. The human MutS and MutL proteins form heterodimeric complexes that mediate the initial steps of MMR, including the recognition of mismatched base(s) arising from errors in replication, and signaling downstream proteins to facilitate mismatch removal. However, MMR complexes also recognize damaged-base mispairs resulting from exposure to environmental genotoxins or treatment with chemotherapeutic agents and mediate cell cycle arrest and apoptosis. As a consequence of their defective MMR, Lynch syndrome tumors and sporadic colorectal cancers display increased instability at short repeat sequences, termed microsatellite instability. In addition, these tumors display resistance to DNA damaging agents, and thus fail to respond to conventional chemotherapy. For example, while the 5-Fluorouracil (5-FU) treatment of MMR-proficient colorectal cancers results in a beneficial outcome, the same is not the case with MMR-deficient sporadic colorectal or Lynch syndrome cancers. Of additional concern, the treatment of cancer patients with conventional chemotherapeutic agents frequently induces secondary therapy-related leukemias (e.g. Acute Myeloid Leukemia / Myelodysplastic Syndrome), which may be caused by selection for hematopoietic precursor cells with MMR-defects. As these cells proliferate they accumulate further mutations and increased resistance to anticancer agents. Thus the development of novel therapeutic strategies that efficiently and selectively target primary cancers and prevent the formation of therapy-induced secondary cancers would be highly desirable. A promising new direction to achieve these goals is the harnessing of synthetic lethality, where the simultaneous loss of two otherwise non- essential factors is fatal for cells. In this application we propose to identify the core genetic networks related to MMR in two highly divergent model eukaryotes, the fission (Schizosaccharomyces pombe; Sp) and budding (Saccharomyces cerevisiae; Sc) yeasts. We will utilize this information to predict (and test) synthetic sick or lethal interactions in defined MMR- deficient mouse and human cancer cell lines. Our proposed studies will not only identify novel interactions and/or functions of the MMR genes, but also have the potential to identify highly effective chemotherapeutic strategies for a prevalent human cancer syndrome. PUBLIC HEALTH RELEVANCE: The DNA mismatch repair system (MMR) is essential for maintaining the integrity of mammalian genomes by correcting mismatched base pairs that result from erroneous replication or environmental damage. Defects in MMR are associated with a significant proportion of sporadic colorectal cancer, and are the underlying cause of the Lynch cancer syndrome (also known as HNPCC: hereditary nonpolyposis colorectal cancer). We are studying yeast and mammalian cell lines with mutations in key MMR genes to identify key conserved genetic networks for MMR. The goal of our studies is not only to determine novel interactions and/or functions of essential MMR genes, but also to identify highly effective chemotherapeutic strategies for a prevalent human cancer syndrome.

描述（由申请人提供）：DNA错配修复（MMR）是一种保守的修复途径，对于维持原核生物和真核生物的基因组完整性至关重要。MMR一直是深入研究的重点，因为MMR基因突变是Lynch综合征（HNPCC，遗传性非息肉病性结直肠癌）和相当比例的散发性结直肠癌的根本原因。这些癌症病例中的大多数是由E.大肠杆菌mutS和mutL基因。人MutS和MutL蛋白形成异二聚体复合物，其介导MMR的初始步骤，包括识别由复制错误引起的错配碱基，并向下游蛋白发出信号以促进错配去除。然而，MMR复合物也识别由暴露于环境遗传毒素或用化疗剂治疗引起的受损碱基错配，并介导细胞周期停滞和凋亡。由于其缺陷的MMR，林奇综合征肿瘤和散发性结直肠癌显示在短重复序列的不稳定性增加，称为微卫星不稳定性。此外，这些肿瘤显示出对DNA损伤剂的抗性，因此对常规化疗没有反应。例如，虽然5-氟尿嘧啶（5-FU）治疗MMR-熟练的结直肠癌导致有益的结果，但MMR-缺陷的散发性结直肠癌或Lynch综合征癌症的情况并非如此。另外值得关注的是，用常规化疗剂治疗癌症患者经常诱导继发性治疗相关的白血病（例如急性髓性白血病/骨髓增生异常综合征），这可能是由选择具有MMR缺陷的造血前体细胞引起的。随着这些细胞增殖，它们积累了进一步的突变并增加了对抗癌剂的抗性。因此，开发有效和选择性地靶向原发性癌症并防止治疗诱导的继发性癌症形成的新的治疗策略将是高度期望的。实现这些目标的一个有希望的新方向是利用合成致死性，其中两个非必需因子的同时丢失对细胞来说是致命的。 在这个应用程序中，我们建议确定的核心遗传网络MMR在两个高度不同的模型真核生物，裂变（裂殖酵母粟酒裂殖酵母; SP）和出芽（酿酒酵母; Sc）酵母。我们将利用这些信息来预测（和测试）合成的病态或致命的相互作用，在确定的MMR缺陷的小鼠和人类癌细胞系。我们提出的研究不仅将确定新的相互作用和/或功能的MMR基因，但也有可能确定一个流行的人类癌症综合征的高效化疗策略。 公共卫生相关性：DNA错配修复系统（MMR）是维持哺乳动物基因组完整性的关键，它可以纠正由于错误复制或环境破坏而导致的错配碱基对。MMR缺陷与相当比例的散发性结直肠癌相关，并且是Lynch癌综合征（也称为HNPCC：遗传性非息肉病性结直肠癌）的根本原因。我们正在研究关键MMR基因突变的酵母和哺乳动物细胞系，以确定MMR的关键保守遗传网络。我们研究的目标不仅是确定新的相互作用和/或基本MMR基因的功能，但也确定一个流行的人类癌症综合征的高效化疗策略。