中华放射医学与防护杂志

陶丹,程晶,伍钢,等.人肺腺癌A549细胞低剂量辐射超敏感性及其机制的研究[J].中华放射医学与防护杂志,2009,29(2):147-148.TAO Dan,CHENG Jing,WU Gang,et al.Low dose hyper-radiosensitivity in human lung cancer cell line A549 and its possible mechanisms[J].Chin J Radiol Med Prot,2009,29(2):147-148

人肺腺癌A549细胞低剂量辐射超敏感性及其机制的研究

Low dose hyper-radiosensitivity in human lung cancer cell line A549 and its possible mechanisms

投稿时间：2008-02-02

DOI：10.3760/cma.j.issn.0254-5098.2009.02.007

中文关键词: 低剂量辐射超敏感性 ATM激酶凋亡细胞周期阻滞 A549细胞

英文关键词:Low dose hyper-radiosensitivity ATM kinase Apoptosis Cell cycle arrest A549 cell line

基金项目:湖北省卫生厅重点资助项目(JX2A11)

作者	单位	E-mail
陶丹	430023 武汉, 华中科技大学同济医学院附属协和医院肿瘤中心
程晶	430023 武汉, 华中科技大学同济医学院附属协和医院肿瘤中心	Chenjin1119@hotmail.com
伍钢	430023 武汉, 华中科技大学同济医学院附属协和医院肿瘤中心
吴红革	430023 武汉, 华中科技大学同济医学院附属协和医院肿瘤中心
薛军	430023 武汉, 华中科技大学同济医学院附属协和医院肿瘤中心

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中文摘要:

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0~2 Gy的⁶⁰Coγ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ATM1981Ser-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量的增加而降低。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,P<0.05);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,P>0.05)。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、0.4和0.5 Gy 组,照射后6和12 h细胞发生G₂/M期阻滞(t＝2.87、2.88、4.92和3.70、3.12、8.11,P<0.05),照射后24 h G₂/M期细胞比例下降(t＝3.87、4.77、3.01,P<0.05)。结论 A549细胞存在HRS/IRR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。

英文摘要:

Objective 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 ⁶⁰Coγ-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. ATM1981Ser-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 killing 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 ATM1981Ser-P protein was first observed at 0.2 Gy, followed by an increase over 0.2 Gy, and reached the peak at 0.5 Gy(compared with 0.2 Gy group, t=7.96,P<0.05), with no further increase as the doses at 1.0 and 2.0 Gy(t＝0.69,0.55, P>0.05). 24 hours after irradiation, part cells presented the characteristic morphological change of apoptosis, and the apoptosis curve was coincident with the dose-survival curve. Compared with the control group, the cell cycle had no change post_irradiation to 0.1 and 0.2 Gy. G₂/M phase arrest was manifested at 6 and 12 hours post_irradiation to 0.3,0.4 and 0.5 Gy (t＝2.87,2.88,4.92 and 3.70,3.12,8.11,P<0.05), and the ratio of G₂/M phase was decreased at 24 hours post_irradiation (t＝3.87,4.77,3.01,P<0.05).Conclusion A549 cells displays the phenomenon of hyper_radiosensitivity(HRS)/induced radioresistance(IRR). The model of cell death induced by low dose irradiation is mainly apoptosis. The activity of ATM and cell cycle change might play an important role in HRS/IRR.

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