Relation between DNA repair enzyme and anti-cancer agents

恶性血液病是一种对化疗有反应的疾病，是可望治愈的疾病。然而，复现情况和原阻力的存在是一个重要的问题。多药耐药和获得性耐药是临床上的重要问题，本研究从DNA修复基因(Ref-1/APE和拓扑异构酶I)与抗癌药物耐药性的关系出发，采用RT-PCR方法克隆了DNA损伤修复基因Ref-1/APE。将此DNA克隆到载体中，并将其导入人白血病细胞系K562。该过表达的Ref-1与荧光蛋白GFP结合。因此，在共聚焦显微镜下观察到，GFP-ref1融合蛋白主要存在于K562细胞的胞核中。此外，它也是…更重要的是，用Western blotting方法检测到融合蛋白过度表达。检测了多种抗肿瘤药物的敏感性，其中已知的拓扑异构酶I抑制剂喜树碱对药物敏感性有增强作用。拓扑异构酶I与DNA的可分离复合体的增加是其易感性增加的机制之一。以抑制拓扑异构酶I为靶酶的喜树碱在拓扑异构酶I缺失和突变的细胞系中与三氧化二砷表现出交叉耐药。在拓扑异构酶正常和突变的细胞系中，三氧化二砷对氧自由基的增加作用没有差异，提示拓扑异构酶I参与了三氧化二砷的抗癌作用。三氧化二砷的敏感性与解毒酶GSH的量成反比关系。研究还表明，拓扑异构酶I参与了抗肿瘤药物诱导细胞凋亡时DNA舵的形成。较少

The hematological malignancy is has been changed as a disease which reacts to the chemotherapy and can be expected to be cure. However the existence of the recurrence case and the primary resistance is the important problem. We have so far made the examinations about the resistance mechanisms and its conquest by establishing various drug resistance cell lines.The multi-drug resistance and acquisition resistance are important problems clinically, and we are considering relation by the DNA repair gene (Ref-1/APE and topoisomerase I) and anti-cancer agent resistance in this study.The cloning of DNA damage repair gene Ref-1/APE was performed using the rtPCR method. This DNA was included in the vector and transfected into the human leukemia cell line K562. This over-expressed Ref-1 is combined with the fluorescence protein GFP. Therefore it was detected under the confocal microscope that GFP-ref1 fusion protein was mainly discovered in the nucleus of K562 after transfection. Moreover, it al … More so detected that fusion protein was over-expressed using Western blotting methods. The susceptibility of various anti-neoplasm agents was examined, and the susceptibility enhancement effect was seen in the camptothecin which is known topoisomerase I inhibitor. The increase of deavable complexes of topoisomerase I and DNA was existed, and it was considered as one of the mechanism of susceptibility increase. Camptothecin which inhibit topoisomerase I as target enzyme showed cross-resistance with arsenic trioxide in a topoisomerase I deficit and mutation cell lines. There is no difference in the increase of the oxygen radical by arsenic trioxide in topoisomerase normal and mutation cell lines, and it was suggested that topoisomerase I was involving in the anticancer action of arsenic trioxide. The inverse proportion relation between the susceptibility of arsenic trioxide and the quantity of detoxification enzyme GSH was detected. It was also showed that topoisomerase I participated in generating of the DNA rudder at the time of the apotosis by the anti-neoplasm agent. Less