| TAO Dan,CHENG Jing,WU Gang,XUE Jun.Low dose hyper-radiosensitivity in human lung cancer cell line A549 and its possible mechanisms[J].Chinese Journal of Radiological Medicine and Protection,2009,29(2):147-148 |
| Low dose hyper-radiosensitivity in human lung cancer cell line A549 and its possible mechanisms |
| Received:February 02, 2008 |
| DOI：10.3760/cma.j.issn.0254-5098.2009.02.007 |
| KeyWords:Low dose hyper-radiosensitivity ATM kinase Apoptosis Cell cycle arrest A549 cell line |
| FundProject:湖北省卫生厅重点资助项目(JX2A11) |
| Author Name | Affiliation | E-mail | | TAO Dan | Cancer Center, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430023, China | | | CHENG Jing | Cancer Center, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430023, China | Chenjin1119@hotmail.com | | WU Gang | Cancer Center, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430023, China | | | XUE Jun | Cancer Center, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430023, China | | | 薛军 | Cancer Center, Union Hospital, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430023, China | |
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| Abstract:: |
| 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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