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损害剂构成一类重要的抗肿瘤 药物，其中大多数是诱变的体外系统。 这是高度的 这些药物的诱变特性可能有助于 基本上是化学疗法的某些不良反应，例如 随着肿瘤中耐药性的获取和发展 长期幸存者的第二癌。 最终目标 拟议的研究是对机制的理解 哪种特定形式的药物诱导的DNA损伤最终导致 恶性和耐药性涉及的遗传改变。 这样的理解将在选择中有用，并且 发展潜在的诱变和致癌药。 为了追求这个目标，一个更直接的目标是 确定某些药物产生的突变类型 在模型系统中，并识别初始DNA病变 负责这些突变。 博来霉素的诱变和 Neocarzinototin已在原核生物中进行了详细检查 基于lambda噬菌体的CI基因的系统。 提出的实验 涉及酶促修复和其他体外修饰 药物损坏的DNA旨在检验两个替代假设 这些研究建议（i），特定类别的氧化 昆虫/肾上腺素的位点，即伴随的位点 互补链中相反的断裂主要是 负责基础取代诱变和（ii） 醛中氧化中醛部分的次要反应 肾上腺素/肾上腺素的位点起着至关重要的作用。 其他研究 将针对确定是否类似突变 机理发生在哺乳动物细胞中复制的穿梭载体中 以及博来霉素是否专门诱导C-HA-激活 正如其突变所预测的，在密码子12处的RAS-1癌基因 核系统的特异性。 氮芥末也 Lambda CI基因中强诱变，类似的方法 将被用来确定突变特异性并确定 大肠杆菌和哺乳动物模型中的诱变DNA病变。 最后，研究药物诱导的缺失的机制 突变将从博来霉素的克隆和测序开始 CHO细胞中APRT基因的诱导缺失。