GENOTOXICITY OF DNA-DIRECTED ANTINEOPLASTIC AGENTS

DNA 定向抗肿瘤药物的基因毒性

• 批准号: 3180855
• 负责人: Lawrence F Povirk
• 金额: $ 11.16万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-08-01 至 1993-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3180855
• 关键词: DNA repair; Escherichia coli; aldehydes; antineoplastics; bacteriophage lambda; bleomycin; chemical carcinogenesis; crosslink; cytotoxicity; drug adverse effect; gene deletion mutation; genetic manipulation; molecular oncology; molecular site; mutagen testing; neocarzinostatin; nitrogen mustard; oxidation reduction reaction; plasmids; protooncogene; tissue /cell culture; transposon /insertion element

DNA-damaging agents constitute an important class of antineoplastic drugs, most of which are mutagenic in vitro systems. It is highly likely that the mutagenic properties of these agents contribute substantially to some of the adverse effects of chemotherapy, such as acquisition of drug resistance in tumors, and development of second cancers in long-term survivors. The ultimate objective of the proposed research is an understanding of the mechanisms by which specific forms of drug-induced DNA damage eventually lead to genetic alterations involved in malignancy and drug resistance. Such an understanding would be useful in the selection and development of potentially less mutagenic and carcinogenic drugs. In pursuit of this objective, a more immediate goal is the determination of the types of mutations produced by certain drugs in model systems, and identification of the initial DNA lesions responsible for those mutations. Mutagenesis by bleomycin and neocarzinostatin has been examined in detail in a prokaryotic system based on the cI gene of lambda phage. Proposed experiments involving enzymatic repair and other in vitro modifications of drug-damaged DNA are designed to test two alternative hypotheses suggested by these studies (i) that a specific class of oxidized apurinic/apyrimidinic sites, i.e., those accompanied by closely opposed breaks in the complementary strand, are primarily responsible for base substitution mutagenesis and (ii) that secondary reactions of the aldehyde moiety in the oxidized apurinic/apyrimidinic sites play a critical role. Other studies will be directed toward determining whether similar mutational mechanisms occur in shuttle vectors replicated in mammalian cells and whether bleomycin specifically induces activation of the c-Ha- ras-1 oncogene at codon 12, as predicted from its mutational specificity in the prokaryotic system. Nitrogen mustard also strongly mutagenic in the lambda cI gene, and similar approaches will be employed to determine mutational specificity and identify mutagenic DNA lesions, in both E. coli and mammalian models. Finally, studies on the mechanisms of drug-induced deletion mutations will begin with the cloning and sequencing of bleomycin- induced deletions in the aprt gene in CHO cells.

DNA损伤剂是一类重要的抗肿瘤药物 药物，其中大部分在体外系统中具有致突变性。 它是高度 这些物质的诱变特性可能有助于 显着减少化疗的一些不良反应，例如 作为肿瘤耐药性的获得，以及 长期幸存者的第二种癌症。 最终目标是 拟议的研究是对机制的理解 药物引起的 DNA 损伤的具体形式最终会导致 涉及恶性肿瘤和耐药性的基因改变。 这种理解对于选择和 开发潜在的致突变性和致癌性较低的药物。 为了实现这一目标，更近期的目标是 确定某些药物产生的突变类型 在模型系统中，以及初始 DNA 损伤的识别 对这些突变负责。 博莱霉素诱变和 新制癌菌素已在原核生物中进行了详细检查 基于 lambda 噬菌体 cI 基因的系统。 提议的实验 涉及酶修复和其他体外修饰 药物损伤的 DNA 旨在测试两种替代假设 这些研究表明 (i) 一类特定的氧化 无嘌呤/无嘧啶位点，即那些密切伴随的位点 互补链中的相反断裂，主要是 负责碱基取代诱变，并且 (ii) 氧化产物中醛基的副反应 无嘌呤/无嘧啶位点起着关键作用。 其他研究 将直接确定是否存在相似的突变 在哺乳动物细胞中复制的穿梭载体中发生的机制 以及博莱霉素是否特异性诱导 c-Ha- 的激活 ras-1 癌基因位于密码子 12，根据其突变预测 原核系统的特异性。 氮芥还有 lambda cI 基因具有强诱变性，以及类似的方法 将用于确定突变特异性并识别 大肠杆菌和哺乳动物模型中的 DNA 突变损伤。 最后，药物诱导缺失的机制研究 突变将从博来霉素的克隆和测序开始 诱导 CHO 细胞中 aprt 基因缺失。