Begg A C, van der Kolk P J, Dewit L, Bartelink H
Int J Radiat Biol Relat Stud Phys Chem Med. 1986 Nov;50(5):871-84. doi: 10.1080/09553008614551291.
The ability of cis-diamminedichloroplatinum (II) (c-DDP) to enhance radiation-induced cell killing was tested on oxic RIF1 tumour cells in monolayer culture. Marked radiosensitization of the survivors of a 1 h drug treatment was found with all c-DDP doses tested, with enhancement ratios increasing from 1.2 to 2.2 with increasing drug dose. Isobologram analyses showed that the interactions of c-DDP with X-rays were supra-additive. To test whether part of the enhancement was due to a selection of subpopulations, the diploid and tetraploid RIF1 cells, which normally coexist in culture, were separated by unit gravity velocity sedimentation, and by developing diploid and tetraploid clones. Both methods showed that there was little difference in either drug sensitivity or radiation sensitivity between diploid and tetraploid cells. DNA histograms obtained by flow cytometry showed little or no cycle progression during the 1 h drug treatment. These data indicate that the radiosensitization was not the result of the drug exposure leaving cells in a radiosensitive phase. The observed radiosensitization, therefore, appears to have resulted from a true drug/X-ray interaction.
在单层培养的有氧RIF1肿瘤细胞上测试了顺二氯二氨铂（II）（c-DDP）增强辐射诱导细胞杀伤的能力。在所测试的所有c-DDP剂量下，均发现1小时药物处理后的存活细胞有明显的放射增敏作用，随着药物剂量增加，增强比从1.2增加到2.2。等效线图分析表明，c-DDP与X射线的相互作用是超相加的。为了测试部分增强作用是否是由于亚群的选择，通过单位重力速度沉降以及通过培养二倍体和四倍体克隆，将通常在培养中共存的二倍体和四倍体RIF1细胞分离。两种方法均表明二倍体细胞和四倍体细胞在药物敏感性或辐射敏感性方面几乎没有差异。通过流式细胞术获得的DNA直方图显示，在1小时药物处理期间几乎没有或没有细胞周期进展。这些数据表明，放射增敏不是药物暴露使细胞处于放射敏感阶段的结果。因此，观察到的放射增敏似乎是由真正的药物/ X射线相互作用导致的。
