Mansoor Farah, Ali Rashid
Department of Biochemistry, Faculty of Medicine, A.M.U. Aligarh-202002, U.P., India.
Clin Biochem. 2007 Sep;40(13-14):928-35. doi: 10.1016/j.clinbiochem.2006.10.012. Epub 2006 Nov 21.
To study the binding of chromatin modified with reactive oxygen species (ROS) with circulating autoantibodies present in cancer patients.
Chromatin isolated from goat liver was modified by superoxide radical plus singlet oxygen and hydroxyl radicals. Sera from 47 patients with various types of cancers were tested for binding to native and modified chromatin by direct binding and competition ELISA.
Maximum modification of thymine (54%) was found in case of chromatin modified with hydroxyl radical whereas by the combined action of singlet oxygen and superoxide anion radical, guanine was modified most (72%). Autoantibodies in cancer sera recognized modified chromatin in preference to native chromatin. Band shift assay with affinity-purified IgG from sera of cancer patients reiterated the results obtained with serum samples.
Greater recognition of ROS-modified chromatin with the autoantibodies in cancer sera is indicative of reactive-oxygen-species-induced chromatin damage in cancer patients.
研究经活性氧（ROS）修饰的染色质与癌症患者体内循环自身抗体的结合情况。
从山羊肝脏分离的染色质用超氧自由基加单线态氧和羟基自由基进行修饰。通过直接结合和竞争ELISA检测47例不同类型癌症患者血清与天然和修饰染色质的结合情况。
在用羟基自由基修饰的染色质中，胸腺嘧啶的修饰程度最高（54%），而在单线态氧和超氧阴离子自由基的联合作用下，鸟嘌呤的修饰程度最高（72%）。癌症血清中的自身抗体优先识别修饰后的染色质而非天然染色质。用癌症患者血清中亲和纯化的IgG进行的凝胶迁移试验重复了血清样本的结果。
癌症血清中的自身抗体对ROS修饰染色质的识别增加，表明癌症患者存在活性氧诱导的染色质损伤。
