中文摘要：

目的 放疗后残存癌细胞重新克隆是鼻咽癌放疗复发的主要原因，本实验旨在分析照射残存癌细胞的生物学特征。方法 MTT法测定6MV-X射线照射人鼻咽高分化鳞癌细胞株CNE1的近致死剂量，用近致死量照射获得残存癌细胞存活克隆，然后用流式细胞仪检测存活克隆与亲本细胞株的细胞周期分布，应用二维电泳和质谱技术分析两者的蛋白质表达改变。结果 用15Gy近致死量照射CNE1得到了照射存活克隆，并命名为CNEI-15GyR。CNE1-15GyR与亲本细胞株相比：G1／G0期比例增高而G2／M期比例降低；有98个蛋白质表达差异点，其中76个蛋白质斑点上调，22个蛋白质斑点下调；对其中上调的20个蛋白质斑点进行了质谱鉴定，发现细胞间叶来源的中间丝蛋白Vimentin在存活克隆CNE1—15GyR中表达增高。结论照射筛选的存活克隆CNE1—15GyR与亲本细胞株CNE1相比生物学性状发生了改变，细胞间叶来源的中间丝波形蛋白Vimentin在CNE1-15GyR克隆中表达增高，可能与G1／G0期比例增高有关。

英文摘要：

Objective To analyze the biological characteristics of the survival clones from nasopharyngeal carcinoma（ NPC） cell line CNE1 cells irradiated with approximately-lethal dose. Methods The approximately-lethal dose of 6MV-X-ray for CNE1 was determined by MTT assay, and the cells were exposed to this dose. The survival and the parent CNE1 cells were tested for the cell cycle distribution by the flow cytometry, and the changes of their proteins were analyzed by two-dimensional gel electrophoresis and MALDI-TOF-MS. Results The CNEl-15GyR survival cell clones were attained after CNE1 cells were irradiated with 6MV-X-ray of 15 Gy. Compared with the parent CNE1, higher G1/G0 and lower G2/M and 98 different protein spots （up-regulation at 76 spots and down- regulation in 22） were found in the CNE1-15GyR. The 20 up-regulated spots were identified by MALDI-TOF-MS. The expressions of intermediate filaments Vimentin from cell intermediate matrix were enhanced in CNE1-15GyR. Conclusion The biological characteristics of CNE1-15GyR have been changed compared with the parent cell lines. The enhanced expression of Vimentin in the CNE1-15GyR may be related to the higher ratio of G1/G0 in the cell cycle.