ADDUCTS OF MITOMYCIN C WITH NUCLEOTIDES

丝裂霉素C(MC)是一种广泛应用的抗生素和抗肿瘤药物 在临床癌症化疗中。它的行动模式一直是 20多年来深入研究和思索的课题， 自从发现它能引起DNA的共价交联后。 最近我们阐明了MC激活的基本化学。 及其与DNA的最终反应产物，包括MC-DNA 交叉链接。我们的目标是将三大 对MC生物效应的反应产物，即TO 确定(A)在抗肿瘤和细胞毒性方面哪个更有效 活动，(B)--为何更有效；及(C)如何加强 在细胞内形成这种有效的反应。博大精深 长期的目标是了解细胞的分子基础 丝裂霉素类药物的抗肿瘤活性及其意义 适用于癌症的新药设计和治疗方案 化疗。 首先，将检查MC和DNA的三个加合物的 使用足迹技术在特定DNA序列上定位 以及将Ba131作为消化的工具。每种加合物对人体的影响 DNA构象将通过检查构象进行评估 在单个位置由三个人中的每一个修饰的寡核苷酸 加成物，作为模型。对细胞培养中形成的加合物的分析将 用作(I)胞内02对交联剂的影响的探针 MC的效率，(Ii)三种加合物的相对细胞毒性， (3)通过细胞修复去除加合物的动力学。切除 加合物DNA的修复将在体外系统中进行研究，使用 单位点加成的DNA片段。两个MC模拟，更有效 然后将检查亲本MC的分子基础 通过比较它们的激活和DNA，它们的效率更高 与MC的反应性。

Mitomycin C (MC) is an antibiotic and antitumor agent widely used in clinical cancer chemotherapy. Its mode of action has been the subject of intensive study and speculation for more than 20 years, since the discovery that it induced covalent crosslinking of DNA. Recently we elucidated the basic chemistry of the activation of MC and its ultimate reaction products with DNA including the MC-DNA crosslink. Our objective is to relate each of the three major reaction products to the biological effects of MC, i.e. to determine (a) which is more effective for antitumor and cytotoxic activities, (b)-why is it more effective and (c) how to enhance the formation of such effective reactions in the cell. The broad and long-term objective is to understand the molecular basis of the antitumor activity of the mitomycins and make this knowledge applicable to new drug design and treatment protocols in cancer chemotherapy. First, the three adducts of MC and DNA will be examined for their location at specific DNA sequences, using footprinting techniques as well as Ba131 digestion as a tool. Effects of each adduct on DNA conformation will be assessed by examining the conformations of oligonucleotides modified at a single site by each of the three adducts, as models. Assay of adducts formed in cell cultures will be used as probe for (i) effect of intracellular 02 on crosslinking efficiency of MC, (ii) relative cytotoxicity of the three adducts, (iii) kinetics of removal of adducts by cellular repair. Excision repair of adducted DNA will be studied in an in vitro system, using single-site adducted DNA fragments. Two MC analogs, more effective than the parent MC will be examined for the molecular basis of their greater effectiveness by comparing their activation and DNA- reactivity with those of MC.