吉西他滨对人鼻咽癌细胞系CNE-1的放射增敏作用

Radiosensitive effect of gemcitabine on nasopharyngeal carcinoma CNE-1 cell line

目的:观察吉西他滨对鼻咽癌细胞CNE-1的放射增敏作用并探讨其作用机理。方法:用克隆形成法制作不同处理条件的细胞存活曲线,用流式细胞仪分析测定细胞周期分布。结果:单纯用药0.1μmol/L和2μmol/L吉西他滨短时间作用时(12小时)未见到肿瘤细胞毒性作用。两个浓度的吉西他滨处理CNE-1鼻咽癌细胞12小时和24小时后均见到放射增敏作用,放射增敏比(SERD0)及2Gy时的放射增敏比(SERSF2)分别为1.36,1.83;1.56,2.16及1.55,1.36,1.43,1.40。0.1μmol/L和2μmol/L的吉西他滨作用24小时后照射均见到G1期细胞阻滞。准阈剂量(Dq)值在2μmol/L中比较低,特别是在作用24小时后照射组。结论:吉西他滨对CNE-1鼻咽癌细胞具有明显的放射增敏作用,并且在高剂量照射时(Gy)随着剂量的增加及作用时间的延长增敏作用愈加明显,其作用机制可能与该药能阻止细胞由G1期进入S期及在高浓度、长时间作用时亚致死性损伤修复比较少有关。

Objective：To observe the effect and mechanism of gemcitabine-induced radiosensitization on CNE-1 nasopharyngeal carcinoma cell line.Methods：The cell survival curves were obtained by clonogenic assay.The cell cycle phases were measured with flow cytometric analysis.Results：No cytotoxic effect was observed in the groups treated with 0.1μmol/L and 2μmol/L gemcitabine lonely.The radiosensitivities were observed in groups treated with both radiation and gemcitabine（0.1μmol/L and 2μmol/L） after exposed 12hours and 24hours,respectively.The SERD0 were 1.36,1.83 and 1.56,2.16 respectively.The G1 cell cycle phase block was observed in two consistency groups after exposing for 24 hours.Dq were rather lower in 2μmol/L groups especially that exposed for 24 hours.Conclusion：The radiosensitivity was obviously observed in radiation groups treated with both 0.1μmol/L（lower dose）and 2μmol/L（higher dose） gemcitabine.The effect was more obviously as the consistency and the exposing time increased.The block of cell cycle from G1 to S and decrease of sublethal damage repair might be contributed to the mechanism.