中文摘要：

目的 探讨2、4 Gy X线照射后人肺腺癌细胞株A549以及非小细胞肺癌（NSCLC）患者血清中miR-520d-3p的表达变化及其意义.方法 用2、4 Gy X线分别照射体外培养的A549细胞,以实时定量聚合酶链反应（RT-qPCR）检测A549细胞中miR-520d-3p表达水平;分别将0、2、4 Gy X线照射后的A549细胞经尾静脉注射制备裸鼠肺转移动物模型,检测裸鼠肺组织及血清中miR-520d-3p的表达水平;收集NSCLC患者血清样本,检测miR-520d-3p表达水平.结果 对照组（0 Gy）、2、4 Gy X线照射A549细胞48 h后,miR-520d-3p相对表达水平分别为1.00±0.03、1.47±0.10和1.84±0.09,差异有统计学意义（F=94.350,P=0.000）;在裸鼠肺组织中,注射10周后与空白对照组相比,0、2与4 Gy照射组miR-520d-3p表达水平升高,分别为2.33±0.13、8.24±0.25、3.46±0.14,差异无统计学意义（F=1.787,P=0.227）,在血清中表达水平升高,分别为11.43±2.30、10.22±4.42、8.99±3.67,差异无统计学意义（F=1.547,P=0.246）;20例NSCLC患者（腺癌10例,鳞状细胞癌10例）血清中有11例（55%）高表达miR-520d-3p.结论 2、4 Gy X线照射可提高A549细胞miR-520d-3p的体内、外表达水平,可能与增强A549细胞体内、外侵袭转移能力相关;NSCLC患者50%以上的血清样本中miR-520d-3p表达显著升高,可能作为NSCLC诊断的新的血清标志物.

英文摘要：

Objective To investigate the expression of miR-520d-3p in 2 and 4 Gy X-ray irradiated A549 cells, serum samples of non-small cell lung cancer （NSCLC） patients and its significance. Methods Real time quantitative PCR （RT-qPCR） was employed to detect the expression miR-520d-3p in 2 and 4 Gy X-ray irradiated A549 cells in vitro. Besides, 0, 2 and 4 Gy X-ray irradiated A549 cells were used to prepare animal model of nude mice lung metastasis through mainline. The expressions of miR-520d-3p and lung tissue of nude mice were detected, and the serum samples of NSCLC patients were collected to test the expression of miR-520d-3p . Results Compared with the control group （ 0 Gy ） , the expression of miR-520d-3p was up-regulated significantly in 2 and 4 Gy X-ray irradiated A549 cells after 48 hours （1.00±0.03, 1.47±0.10, 1.84 ±0.09 respectively）, and there was a significant difference （F= 94.350, P= 0.000）. Furthermore, compared the control group with injection after 10 weeks, the expressions of miR-520d-3p in nude mice lung tissue in 0, 2 and 4 Gy X-ray irradiated groups were increased （2.33 ±0.13, 8.24 ±0.25, 3.46 ±0.14, respectively） （F=1.787, P= 0.227）, and the expressions in serum were increased （11.43±2.30, 10.22±4.62, 8.99 ±3.67, respectively） （F= 1.547, P= 0.246）. Out of 20 serum samples of NSCLC patients （including 10 cases of adenocarcinoma, 10 cases of squamous carcinoma ）, 11 cases （55%） were detected with up-regulated miR-520d-3p expression. Conclusions 2 and 4 Gy X-ray could increase the expression of miR-520d-3p of A549 cells in vitro and in vivo, which might be correlated with the enhanced invasion and metastasis of A549 cells induced by X-ray in vitro and in vivo. Furthermore, the expressions of miR-520d-3p were increased significantly in over 50%serum samples of NSCLC patients, which might be a new marker for the diagnosis of NSCLC.