MITOMYCIN C-DNA ADDUCTS IN TUMOR CELLS

肿瘤细胞中的丝裂霉素 C-DNA 加合物

• 批准号: 2748882
• 负责人: MARIA TOMASZ
• 金额: $ 20.02万
• 依托单位: HUNTER COLLEGE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-17 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2748882
• 关键词: CHO cells; DNA damage; MCF7 cell; NAD(P)H dehydrogenase; NADPH cytochrome c2 reductase; acidity /alkalinity; adduct; bioassay; cell free system; chemical structure function; crosslink; cytochrome b2; cytochrome b5 reductase; cytotoxicity; enzyme mechanism; glutathione; high performance liquid chromatography; mitomycin C; neoplastic cell; tissue /cell culture; xanthine dehydrogenase

The long-term goal of the proposed studies is to elucidate critical cellular mechanisms involved int he antitumor activity of mitomycin C (MC), a natural product widely employed in clinical cancer chemotherapy, and to translate this information into the improved use of MC and its analogs against cancer. Four intracellular variables will be examined with regards to their effects on the cytotoxicity and DNA-adduct-forming ability of MC in tumor cells: (i) The nature of the enzymes that reductively activate MC; (ii) the glutathione level in the cell; (iii) low intracellular pH; and (iv) monofunctional (decarbamoyl mitomycin C) versus bifunctional mitomycin (MC) as the administered agent. All of the variables will be studies in the EMT66 mouse mammary tumor cell line. Complete MC-DNA adduct patterns formed in the cells will be determined using [3H]-labeled MC and analyzing the radiolableed adducts by HPLC, by a method developed previously in our laboratoy. Analogous analyses will be conducted in cell-free system using purified MC-activating enzymes and EMT6DNA, to evaluate intrinsic (cell-independent) effects of the above variables on DNA adduct patterns. The structures of unknown MC-DNA adducts will be determined. Cytotoxicity of MC to cells with enhanced levels of gluthathione as well as the cytotoxicity of the mitomycin metabolie 2, 7-diaminomitosene will be studied in conjunction with the DNA-adduct analyses. This work is expected to result I identifying in intact cells (i) critical MC-activating enzynes and modulation of their activity by cellular microenvironmental conditions and (ii) the relative cytotoxic importance of MC-DNA cross-links versus MC-monoadducts. The knowledge obtained should contribute to improving the use of the mitomycins in the treatment of cancer.

拟议研究的长期目标是阐明关键 细胞机制涉及丝裂霉素C的抗肿瘤活性 （MC），一种在临床癌中广泛使用的天然产品 化学疗法，并将这些信息转化为改进的使用 MC及其对癌症的类似物。 四个细胞内变量将 关于它们对细胞毒性的影响和 MC在肿瘤细胞中的DNA添加能力：（i） 还原激活MC的酶； （ii）谷胱甘肽水平 细胞； （iii）低细胞内pH； （iv）单功能 （Decarbamoyl丝裂霉素C）与双功能丝裂霉素（MC） 管理代理。 所有变量将是研究 EMT66小鼠乳腺肿瘤细胞系。 完整的MC-DNA加合物 细胞中形成的模式将使用[3H]标记的MC确定 并通过方法分析HPLC的可放射性加合物 以前在我们的Laboratoy中开发。 类似分析将是 使用纯化的MC激活酶在无细胞系统中进行 和emt6DNA，以评估固有的（细胞独立）的作用 DNA加合图案上的上述变量。 未知的结构 将确定MC-DNA加合物。 MC对细胞的细胞毒性 具有增强水平的胶质硫酮以及细胞毒性 丝裂霉素代谢2，7-二氨基氨基苯烷将在 与DNA-ADDUCT分析的结合。这项工作有望 结果我在完整的细胞中识别（i）关键的MC激活enzynes和 通过细胞微环境条件调节其活性 （ii）MC-DNA交联的相对细胞毒性重要性 与MC单载合相比。 获得的知识应贡献 改善丝裂霉素在癌症治疗中的使用。