Badie C, Iliakis G, Foray N, Alsbeih G, Cedervall B, Chavaudra N, Pantelias G, Arlett C, Malaise E P
Laboratoire de Radiobiologie Cellulaire, Institut Gustave-Roussy, Villejuif, France.
Radiat Res. 1995 Oct;144(1):26-35.
The aim of this work was to measure simultaneously and in a quantitative manner double-strand breaks (DSBs), interphase chromosome breaks and cell lethality either immediately after irradiation, or at various times thereafter (up to 24 h), in cells of three nontransformed human fibroblast cell lines of widely different intrinsic radiosensitivity. We wished to assess initial damage, repair kinetics and residual damage at the DNA and the chromosome level, and to correlate these parameters with cell killing. We employed HF19 cells, a normal fibroblast cell line, AT2 cells, a radiosensitive cell line from a patient suffering from ataxia telangiectasia (AT), and 180BR cells, a radiosensitive cell line from a patient with no clinical symptoms of AT. AT2 and 180BR cells, in addition to being radiosensitive, also display a reduced ability to repair potentially lethal damage compared to HF19 cells. The yield of DSBs, as measured by pulsed-field gel electrophoresis, is similar in all three cell lines (slopes correspond to 1.6-1.7% Gy-1 of DNA-associated radioactivity released from the gel well into the lane). In contrast, residual DSBs measured 24 h after irradiation are almost zero for HF19 cells (0.1% confidence interval = 0-1.4%), but are 12.5% (+/- 2.3%) and 43.8% (+/- 1.2%) of those measured immediately after irradiation in AT2 and 180BR cells, respectively. Residual interphase chromosome breaks are 11.6% (+/- 1.6%), 29.7% (+/- 5.7%) and 41.4% (+/- 2.2%) of those measured immediately after irradiation in HF19, AT2 and 180BR cells, respectively. Neither the initial yield of DSBs nor that of excess interphase chromosome breaks can explain the differences in radiosensitivity between the three cell lines; however, there is a correlation between residual DSBs, rate of DSB rejoining at 24 h, residual interphase chromosome breaks on the one hand and cell survival on the other hand.
这项工作的目的是，对三种内在放射敏感性差异很大的未转化人成纤维细胞系的细胞，在照射后即刻或之后不同时间点（长达24小时），同时以定量方式测量双链断裂（DSB）、间期染色体断裂和细胞致死率。我们希望评估DNA和染色体水平的初始损伤、修复动力学及残留损伤，并将这些参数与细胞杀伤相关联。我们使用了HF19细胞（一种正常成纤维细胞系）、AT2细胞（来自一名患有共济失调毛细血管扩张症（AT）患者的放射敏感细胞系）和180BR细胞（来自一名无AT临床症状患者的放射敏感细胞系）。与HF19细胞相比，AT2和180BR细胞除了具有放射敏感性外，修复潜在致死损伤的能力也降低。通过脉冲场凝胶电泳测量，所有三种细胞系中DSB的产量相似（斜率对应于从凝胶孔释放到泳道中的与DNA相关的放射性的1.6 - 1.7% Gy-1）。相比之下，照射后24小时测量的残留DSB，HF19细胞几乎为零（0.1%置信区间 = 0 - 1.4%），但在AT2和180BR细胞中分别为照射后即刻测量值的12.5%（±2.3%）和43.8%（±1.2%）。残留间期染色体断裂分别为HF19、AT2和180BR细胞照射后即刻测量值的11.6%（±1.6%）、29.7%（±5.7%）和41.4%（±2.2%）。DSB的初始产量和额外间期染色体断裂的产量均无法解释这三种细胞系之间放射敏感性的差异；然而，一方面残留DSB、24小时时DSB重新连接的速率、残留间期染色体断裂与另一方面细胞存活之间存在相关性。
