鼻咽癌细胞株CNE1、HONE1、C666-1和CNE2的亚致死性损伤修复速度测定

Determination of the repair half-time of human nasopharyngeal carcinoma cell lines CNE1,CNE2,HONE1 and C666-1

目的测定CNE1、HONE1、C666-1和CNE2的亚致死性损伤修复速度参数-半修复时间(repair half-time,T1/2)。方法设0s、15s、30s、1h、2h、4h及6h共7个间隔时间,将8Gy照射剂量分为平分为两个4Gy间断照射4株细胞。采用集落形成法得到4株细胞在不同间隔时间两个4Gy照射后的存活分数。拟合细胞存活分数随间隔时间延长的变化曲线,并测算出T1/2。结果CNE1、HONE1、C666-1和CNE2的T1/2分别为18、22、29和27s。结论鼻咽癌细胞的亚致死性损伤修复速度较快。提示调强放疗中被延长的分次照射时间(15～45s)可能导致鼻咽癌细胞的辐射死灭效应降低。

Objective To determine the repair half-time （T1/2）,a speed parameter of sub-lethal damage repair （SLDR）,of human nasopharyngeal carcinoma （NPC） cell lines CNE1,HONE1,C666-1 and CNE2.Methods A total radiation dose of 8 Gy divided into 4＋4 Gy was delivered to the cell lines at the interval of 0 s,15 s,30 s,1 h,2 h,4 h or 6 h.The cell survival fractions were determined using the standard cell clonogenic assay.The curves of the changes in the surviving cell fraction after a total dose of 8 Gy,as a function of the interval between the two doses of 4 Gy,were fitted manually,and the T1/2 of each cell line was calculated according to the curves.Results The T1/2 of CNE1,HONE1,C666-1 and CNE2 were 18 s,22 s,29 s and 27 s,respectively.Conclusion The speed of SLDR of NPC cells is quite rapid,indicating that the fraction delivery time longer than 20 s might decrease the effect of radiotherapy.