In Situ Detection of Cellular DNA Strand Breaks Induced by Antitumor Drugs Using Nick Translation

在体外和小鼠肉瘤细胞中检测到烷化剂卡波昆(CQ)和热(43ﾟC)诱导的细胞DNA链断裂。在大肠杆菌DNA聚合酶I和[~(3 H)]-1标记的dTTP存在下，人工翻译DNA中的断裂位点，并通过放射自显影观察细胞核中的颗粒。与对照细胞的研究结果相比，这些断裂以剂量和时间依赖的方式增加。我们的发现表明，暴露于CQ或高温后，细胞的存活反应降低，而DNA链断裂水平增加。缺口转移法是一种在体内外条件下半定量检测药物和热诱导的肿瘤细胞DNA损伤的快速原位检测方法。

Cellular DNA strand breaks induced by an alkylating agent : Carboquone (CQ), and heat (43^ﾟC) was detected in HeLa cells in vitro and mouse sarcoma-180 cells in vivo. The breaks sites in the DNA were translated artificially in the presence of Escherichia coli DNA polymerase I and [ ^3H] -1 abeled dTTp and sites in the DNA were visualized byautoradiographic observation of grains in the nuclei. These breaks increased in a dose and time dependent manner, compared to findings in the control cells.Our findings show that the surviving response of cells decreases while the level of DNA strand breaks increases following exposure to CQ or heat. The nick translation method is a rapid in situ assay fordetermining drug and heat induced DNA damage of tumor cells, under in vitro and in vivo conditions and in a semi-quantitative manner.