Suzuki M, Kase Y, Nakano T, Kanai T, Ando K
Space and Particle Radiation Science Research Group, National Institute of Radiological Sciences, Chiba-shi, Japan.
Adv Space Res. 1998;22(12):1663-71. doi: 10.1016/s0273-1177(99)00031-9.
We have studied the relationship between cell killing and the induction of residual chromatin breaks on various human cell lines and primary cultured cells obtained by biopsy from patients irradiated with either X-rays or heavy-ion beams to identify potential bio-marker of radiosensitivity for radiation-induced cell killing. The carbon-ion beams were accelerated with the Heavy Ion Medical Accelerator in Chiba (HIMAC). Six primary cultures obtained by biopsy from 6 patients with carcinoma of the cervix were irradiated with two different mono-LET beams (LET = 13 keV/micrometer, 76 keV/micrometer) and 200kV X rays. Residual chromatin breaks were measured by counting the number of non-rejoining chromatin fragments detected by the premature chromosome condensation (PCC) technique after a 24 hour post-irradiation incubation period. The induction rate of residual chromatin breaks per cell per Gy was the highest for 76 keV/micrometer beams on all of the cells. Our results indicated that cell which was more sensitive to the cell killing was similarly more susceptible to induction of residual chromatin breaks. Furthermore there is a good correlation between these two end points in various cell lines and primary cultured cells. This suggests that the detection of residual chromatin breaks by the PCC technique may be useful as a predictive assay of tumor response to cancer radiotherapy.
我们研究了细胞杀伤与残余染色质断裂诱导之间的关系,研究对象为多种人类细胞系以及通过活检从接受X射线或重离子束照射的患者身上获取的原代培养细胞,目的是确定辐射诱导细胞杀伤的放射敏感性潜在生物标志物。碳离子束由千叶重离子医用加速器(HIMAC)加速。从6名宫颈癌患者身上通过活检获得的6种原代培养细胞,分别用两种不同的单能传能线密度(LET)束(LET = 13 keV/微米,76 keV/微米)和200 kV X射线进行照射。在照射后24小时的孵育期后,通过计数早熟染色体凝集(PCC)技术检测到的未重新连接的染色质片段数量来测量残余染色质断裂。对于所有细胞,每戈瑞每细胞的残余染色质断裂诱导率在76 keV/微米束下最高。我们的结果表明,对细胞杀伤更敏感的细胞同样更容易诱导产生残余染色质断裂。此外,在各种细胞系和原代培养细胞中,这两个终点之间存在良好的相关性。这表明通过PCC技术检测残余染色质断裂可能作为预测肿瘤对癌症放疗反应的一种检测方法。