Holmes A, McMillan T J, Peacock J H, Steel G G
Radiotherapy Research Unit, Institute of Cancer Research, Sutton, Surrey, UK.
Br J Cancer. 1990 Nov;62(5):791-5. doi: 10.1038/bjc.1990.381.
The current use of targeted radiotherapy in the treatment of neuroblastoma has generated a requirement for further information on the radiobiology of these cells. Here we report on studies of the dose-rate effect in two human neuroblastoma cell lines (HX138 and HX142) and the recovery that they demonstrate in split-dose experiments. The sensitivity of the two cell lines to high dose-rate irradiation was confirmed. Surviving fractions at 2 Gy were 0.083 for HX138 and 0.11 for HX142. There was little evidence of a dose-rate effect above 2 cGy min-1 but significant sparing was seen at lower dose rates. Substantial recovery was seen in split-dose experiments on both cell lines, to an extent that was consistent with the linear quadratic equation. The data were used to derive values for the beta parameter of the linear-quadratic equation; the values for the neuroblastomas were higher than for any of the other human tumour cell lines that we have investigated to date. Thus, despite their high sensitivity to ionising radiation HX138 and HX142 do exhibit substantial levels of cellular recovery, suggesting that they may have a significant capacity for repair of radiation-induced lesions.
目前在神经母细胞瘤治疗中使用靶向放疗产生了对这些细胞放射生物学进一步信息的需求。在此，我们报告关于两种人类神经母细胞瘤细胞系（HX138和HX142）剂量率效应及其在分次剂量实验中所表现出的恢复情况的研究。证实了这两种细胞系对高剂量率照射的敏感性。HX138在2 Gy时的存活分数为0.083，HX142为0.11。在剂量率高于2 cGy min-1时几乎没有剂量率效应的证据，但在较低剂量率时可见明显的剂量节省。在两种细胞系的分次剂量实验中均观察到显著的恢复，恢复程度与线性二次方程一致。这些数据被用于推导线性二次方程的β参数值；神经母细胞瘤的值高于我们迄今研究过的任何其他人类肿瘤细胞系。因此，尽管HX138和HX142对电离辐射高度敏感，但它们确实表现出相当程度的细胞恢复，表明它们可能具有修复辐射诱导损伤的显著能力。
