摘要
目的观察miR-18a对A549肺腺癌细胞放射敏感性的影响。方法 qRT-PCR检测2 Gy X线照射A549细胞后miR-18a的变化;将人工合成的miR-18a模拟物(mimics)转染A549细胞,测定不同剂量照射后A549细胞的克隆形成能力,描记细胞存活曲线,测算2 Gy时存活分数(SF2)等指标,判断miR-18a对A549细胞放射敏感性的影响;同时检测过表达miR-18a的A549细胞中共济失调-毛细血管扩张症突变基因(ataxia-telangiectasia mutated,ATM)蛋白,探讨miR-18a对A549细胞放射敏感性影响的分子机制。结果与照射前(1.00±0.04)相比,2 Gy剂量照射后A549细胞miR-18a水平[(0.18±0.04)～(0.31±0.09)]显著降低(P<0.05)。miR-18a过表达后A549细胞放射敏感性增强,miR-18a过表达组、空白对照组SF2分别为0.34,0.48;同时miR-18a过表达的A549细胞中ATM、磷酸化ATM(ATM phospho S1981)水平下降。结论 miR-18a上调A549细胞放疗敏感性,可能与miR-18a下调ATM有关。
Objective To determine the effect of miR-18a on the radiosensitivity of A549 cells and investigate the underlying molecular mechanisms. Methods After A549 cells were treated with 2 Gy X-ray, miR-18a was determined by qRT-PCR. And then miR-18a mimics were transfected into A549 cells, after exposure to X-ray radiation at different doses, surrival fraction was assessed by clonogenie assay. Survival fraction at 2 Gy （SF2） and sensitive enhancement ration （SER） were calculated. The protein levels of ataxia telangieetasia mutated （ATM） kinase and ATM （phospho S1981 ） were determined by Western blotting after up-regulating miR-18a. Results miR-18a was decreased from 1.00 ~0.04 to 0.18 ~0.04 -0.31 ＋_0.09 in A549 cells after exposure to 2 Gy X-ray （P 〈0.05）. miR-18a over-expression increased the radiosensitivity in A549 cells. The SF2 in miR-18a over-expression cells and normal A549 cells was 0.34 and 0.48, respectively. Moreover, the expression levels of ATM and ATM （ phospho S1981 ） were down-regulated in miR-18a over- expressed A549 cells. Conclusion In A549 cells, miR-18a enhances radiosensitivity by inhibiting ATM and ATM （phospho S1981 ）.
出处
《第三军医大学学报》
CAS
CSCD
北大核心
2013年第9期870-873,共4页
Journal of Third Military Medical University
基金
国家自然科学基金(81272496)
重庆市自然科学基金(CSTC2012 jjB0076)~~
