Adducts of mitomycin C with nucleotides.

丝裂霉素C与核苷酸的加合物。

• 批准号: 6888100
• 负责人: MARIA TOMASZ
• 金额: $ 22.77万
• 依托单位: HUNTER COLLEGE
• 依托单位国家: 美国
• 财政年份: 1980
• 资助国家: 美国
• 起止时间: 1980-07-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6888100
• 关键词: DNA repair; adduct; alkylation; antineoplastic antibiotics; binding proteins; cell line; chemical structure; congenital aplastic anemia; cytotoxicity; drug design /synthesis /production; drug hypersensitivity; drug screening /evaluation; free radical oxygen; high performance liquid chromatography; mitomycin C; neoplasm /cancer chemotherapy; neoplasm /cancer pharmacology; nuclear magnetic resonance spectroscopy; nucleic acid sequence; pharmacokinetics; southern blotting; synthetic nucleotide

DESCRIPTION (provided by applicant): Mitomycin C (MC) is a natural antitumor antibiotic used in the clinic for cancer chemotherapy. MC generates six different DNA adducts in tumor cells. One of these is a DNA interstrand cross-link, as a result of bifunctional alkylation of the complementary DNA strands by MC, while the others are adducts of the drug, linked to only one strand of DNA (monoadducts and an intrastrand crosslink). The broad, long-range objective of the present proposal is to elucidate the relationship of each of the six adducts to the cytotoxicity/antitumor activity of MC. In addition, the putative toxic role of reactive oxygen species (ROS), generated by redox cycling of MC, will be examined using Fanconi's Anemia (FA) cells. The first aim of the proposal is to determine whether the known hypersensitivity of FA cells to MC is primarily due to ROS generation or to DNA adduct formation by the drug. These studies will better define the biochemical basis of the unique sensitivities of Faneoni's anemia cells, as well as providing insights into the activities of the mitomycins. The other specific aims serve to detect and characterize biochemical responses unique to the different DNA adducts of MC. In this context we shall investigate differential rates of repair of the adducts in living EMT6 tumor cells in cell culture. Differential modes of nucleotide excision repair of cross-link and monoadducts will be investigated in subcellular systems by constructing 91-mer oligonucleotide duplexes modified site-specifically with the various MC adducts, and using these as substrates for uvrABC excinuclease, or for the repair enzymes present in a mammalian whole cell extract. The same substrates will be used to search for "adduct binding proteins", specific for the cross-link, in cell extracts. Differential inhibition of lesion bypass by DNA polymerases by the different mitomycin monoadducts will also be investigated, using synthetic adduct-template-primer complexes as substrates. These latter experiments are aimed at identifying the basis for the unusually low cytotoxicity of the monoadducts 5 and 6. This research will lead to a better understanding of the molecular and biochemical basis of the antitumor activity and toxicology of MC and, more generally, of other DNA cross-linking agents, a major class of drugs currently used in cancer chemotherapy.

描述（由申请人提供）：丝裂霉素C （Mitomycin C， MC）是临床用于癌症化疗的天然抗肿瘤抗生素。MC在肿瘤细胞中产生六种不同的DNA加合物。其中一种是DNA链间交联，这是MC对互补DNA链进行双功能烷基化的结果，而其他两种是药物的加合物，仅与一条DNA链相连（单加合物和链内交联）。本研究的长远目标是阐明这六种加合物与MC的细胞毒性/抗肿瘤活性之间的关系。此外，MC氧化还原循环产生的活性氧（ROS）的毒性作用将在范可尼贫血（FA）细胞中得到验证。该提案的第一个目的是确定已知的FA细胞对MC的超敏反应主要是由于ROS的产生还是由于药物形成的DNA加合物。这些研究将更好地定义法诺尼贫血细胞独特敏感性的生化基础，并为丝裂霉素的活性提供见解。其他特定目的是检测和表征MC的不同DNA加合物所特有的生化反应。在这种情况下，我们将研究细胞培养中EMT6肿瘤细胞中加合物的不同修复率。我们将在亚细胞系统中研究交联和单加合物的核苷酸切除修复的不同模式，方法是用各种MC加合物构建位点特异性修饰的91聚寡核苷酸双链，并将这些作为uvrABC切酶或哺乳动物全细胞提取物中存在的修复酶的底物。同样的底物将用于在细胞提取物中搜索“加合物结合蛋白”，特异性地用于交联。不同丝裂霉素单加合物对DNA聚合酶损伤绕道的差异抑制也将被研究，使用合成加合物-模板-引物复合物作为底物。这些后一种实验旨在确定单加合物5和6异常低的细胞毒性的基础。这项研究将使人们更好地了解MC的抗肿瘤活性和毒理学的分子和生化基础，更广泛地说，了解其他DNA交联剂，这是目前用于癌症化疗的一类主要药物。