Baisch H, Linden W A, Weigert H D
Int J Radiat Biol Relat Stud Phys Chem Med. 1977 Sep;32(3):209-18. doi: 10.1080/09553007714550921.
The combined action of Daunomycin and irradiation was investigated using mouse L-929 cells in culture. Survival of cells was measured with the colony assay. Sedimentation in alkaline sucrose gradients was used to study repair of DNA single-strand breaks (SSB) in the presence of various concentrations of Daunomycin. A small increase in radio-sensitivity, as measured by decreasing Do, was obtained for doses of Daunomycin that are considerably toxic to the cells (0.1 microgram/ml). However, the Dq values remained constant even at high concentrations indicating that Daunomycin does not interfere with recovery processes. The rate of rejoining of SSB remained constant up to 1.0 microgram/ml, whereas concentrations of Daunomycin as high as 10 microgram/ml reduced the velocity of repair by a factor of 13. Our data show that concentrations of Daunomycin similar to those required for other DNA-binding drugs are required to inhibit SSB repair. For clinical purposes, no increase in tumour-killing efficiency may be expected from a combined treatment with Daunomycin and radiation.
利用培养的小鼠L-929细胞研究了柔红霉素与辐射的联合作用。通过集落试验测定细胞存活率。在存在不同浓度柔红霉素的情况下，用碱性蔗糖梯度沉降法研究DNA单链断裂（SSB）的修复情况。对于对细胞有相当大毒性的柔红霉素剂量（0.1微克/毫升），通过降低Do测量，放射敏感性有小幅增加。然而，即使在高浓度下，Dq值仍保持恒定，这表明柔红霉素不干扰修复过程。在高达1.0微克/毫升的浓度下，SSB的重新连接速率保持恒定，而高达10微克/毫升的柔红霉素浓度使修复速度降低了13倍。我们的数据表明，抑制SSB修复需要与其他DNA结合药物所需浓度相似的柔红霉素浓度。就临床而言，柔红霉素与放疗联合治疗预计不会提高肿瘤杀伤效率。
