miR-125a对肺癌A549细胞放疗敏感性影响机制的初步研究

Effect of miR-125a on radiosensitivity of lung cancer A549 cells

目的探讨miR-125a对肺癌A549细胞放疗敏感性的作用及其机制。方法将A549细胞分为转染miR-125a细胞组(实验组)和转染miR-125a乱序的细胞组(对照组)。采用MTT法检测其生长率、采用集落形成实验测定不同剂量照射的存活分数、Annexin-V/PI双染测定细胞凋亡情况以及蛋白免疫印迹法检测各组细胞中p53蛋白表达情况。结果 q PCR检测显示,miR-125a能够在A549细胞中成功侵袭,且实验组表达量高于对照组(P<0.05);MTT法检测发现,转染后实验组肺癌A549细胞抑制率明显升高,与对照组比较差异具有统计学意义(P<0.01);集落形成实验发现,采用X线照射后,实验组细胞存活分数低于对照组,其中实验组在2 Gy时细胞存活分数降低更为明显(P<0.01);Annexin-V/PI双染法发现,照射后实验组细胞凋亡率升高(P<0.05);蛋白免疫印迹法检测发现,p53蛋白在实验组中升高,与对照组比较差异有统计学意义(P<0.05)。结论 miR-125a细胞能够在A549细胞中成功转染侵袭,其上调后明显增加细胞的凋亡率,X线照射后细胞凋亡升高。这一作用机制可能与miR-125a细胞上调激活p53蛋白活化有关。

Objective To investigate the effect of miR-125a on the radiosensitivity of lung cancer A549 cells and its mechanism. Methods Human lung cancer A549 cells were transfected with miR-125a. The growth rate, survival fraction, and cell apoptosis of A549 ceils and p53 protein level were determined by MTr assay, colony formation assay after irradiation at different doses, Annexin-V/PI double staining and Western blot, respectively. Results qPCR detection showed that miR-125a was successfully transfected into 3.549 cells, and its expression was significantly higher in transfected cells （ P 〈 0.05 ）. MTT assay found that the growth of transfected A549 cells was significantly inhibited compared with nontransfected cells （ P 〈 0. 01 ）. Colony formation demonstrated that after X-ray irradiation, the surviving fraction of transfected A549 cells was lower than that of non-transfected cells, particularly under 2 Gy irradiation （ P 〈 0.01 ）. Annexin-V/PI double staining revealed that the apoptosis rate of transfected 3.549 cells significantly increased after irradiation （ P 〈 0.05 ）. The expression of p53 protein in transfected cells was significantly higher than that in nontransfected ceils （P 〈 0.05 ） as shown in Western blot. Conclusion miR-125a can be successfully transfected in A549 cells, which enhances cell apoptosis rate after irradiation. This effect may be related to the up-regulation of p53 activation.