基础研究·.PDFVIP

主堡墼堑医堂皇堕芝銎查!!鲤生!旦笙望鲞笙!塑垦!也』幽垡丛生里坚!皇四!!Q塑：!塑：丝!塑!：； 人肺腺癌A549细胞低剂量辐射超敏感性 及其机制的研究 陶丹 程晶 伍钢 吴红革 薛军 【摘要】 目的观察A549细胞的低剂量辐射超敏感性现象．探讨其发生的机制。方法A549 细胞接受。一2 GyM60Co 7射线照射后，流式细胞仪对其分选计数，克隆形成法检测细胞存活分数， Western blot法检测ATMl981Ser-P蛋白表达，Hoechst 33258荧光染色法、AnnexinV．FITC／PI双染流式细 胞仪检测细胞凋亡，PI单染流式细胞仪检测细胞周期。结果细胞在0—0．3 Gy表现出单位剂量杀 伤增强，在0．3．0．5 Gy表现出一定的辐射抗性，0．5 Gy后的区域存活分数随辐射剂鼋的增加而降 低。照射后1 h，ATM激酶在0．2 Gy时开始活化，0．5 Gy时活化达高峰(t=7．96，P0．05)；与0．5 Gy相 比1．0和2．0 Gy的活化水平无明显变化(t=0．69、0．55，PO．05)。照射后24 h，部分细胞发生凋亡。 其凋亡曲线与存活曲线相吻合。与未照射组相比，0．1和0．2 Gy组在各时间点(照射后6、12和24 h) 的细胞周期无明显变化，而0．3、O．4和0．5 Gy组，照射后6和12 h细胞发生G2，M期阻滞(t=2．87、 2．船、4．92和3．70、3．12、8．11，P0．05)，照射后24 h G2／M期细胞比例下降(t=3．87、4．77、3．Ol，P 0．05)。结论A549细胞存在HRS／1RR现象，其发生可能与ATM激酶、细胞周期变化有关，凋亡是细 胞死亡的主要方式。 【关键词】低剂量辐射超敏感性； ATM激酶；凋亡；细胞周期阻滞；A549细胞 Low dose hyper-radiosensifivity in human lung canc盯cell line A549 and its possible mechanisms TAO Dan，CHENG Jing，WU Gang。WU Hong-ge，XUE Jun．Cancer Center，Union Hospital，ron面i Medical College of Huazhong University of Science and Technology，Wuhan 430023，China Corresponding author：CHENG以，w，Email：Chenjinlll8@hotma／／．coin 【Abstract】0bjective To study the low dose hyper-radiosensitivity in human lung cancer cell line A549，and its possible mechanisms．Methods Exponentially growing A549 cells were irradiated with”Co弘 rays at doses of 0-2 Gy。Together with flow cytometry for precise cell sorting，cell survival fraction was measured by mean of conventional colony·formation assay．ATMl981Ser-P protein expression was examined by Western blot．Apoptosis was identified by Hoechst 33258 fluorescent staining，and Annexin V·FITC and propidium iodide staining flow cytometry．Cell cycle distribution was observed by flow cytometry．Results There was an excessive cell kifiing per unit dose when the doses were below about 0．3 Gy，and the cells exhibited more resistant response at the doses between 0．3 and 0．5 Gy，the cell survival fraction was decreased as the doses over 0．5 Gy．The expression of ATMl981Ser-P protein wag first observed at 0。2 Gy，fol