MicroRNA-21与乳腺癌细胞MDA-MB-231放射敏感性之间关系的研究

目的:研究MicroRNA-21与乳腺癌细胞MDA-MB-231放射敏感性之间关系及其表达规律。方法:①对乳腺癌细胞MDA-MB-231分别转染miR-21 mimics、miR-21 mimics Scramble(阴性对照)、miR-21 inhibitor、miR-21 inhibitorScramble(阴性对照),转染后进行集落形成实验,通过存活分数(Surviving Fraction SF)的变化检测其辐射敏感性是否发生变化;②时程实验:3Gy X-Ray照射后,分别于0、4、8、12、24 h后,实时荧光定量PCR检测miR-21的表达;③量效实验:0、1、2、4、6Gy X-Ray分别照射细胞24 h后,实时荧光定量PCR检测miR-21的表达。结果:MDA-MB-231细胞转染miR-21mimics后,SF明显升高,与正常对照组比较有显著性差异(P<0.05);MDA-MB-231细胞转染miR-21 inhibitor后,SF明显降低,与正常对照组比较有显著性差异(P<0.05);3GyX射线照射乳腺癌细胞株MDA-MB-231后,miR-21表达量上调,与对照组比较差异具有显著性(P<0.05),并在12 h时达到峰值,24 h时恢复到照前水平;miR-21的表达量随着照射剂量的增加而发生变化,2Gy时达到峰值,照射剂量进一步加大,miR-21表达量开始下调,与对照组比较具有显著性差异(P<0.05),6Gy时miR-21表达量明显低于未照射组。结论:miR-21对于增加乳腺癌细胞株MDA-MB-231的辐射抗性具有一定作用。

Study on the relationship between microRNA-21 and radiation sensitivity of breast cancer cell line MDA-MB-231

Objective:To research the relationship between microRNA-21 and radiation sensitivity of breast cancer cell line MDA-MB-231 and the expression regularity.Methods:Breast cancer cell line MDA-MB-231 was transfected by miR-21 mimics,miR-21 mimics Scramble(negative control group),miR-21 inhibitor,and miR-21 inhibitor Scramble(negative control group),respectively,then colony-forming assay was performed,the change of surviving fraction(SF) was used to detect whether radiation sensitivity changed,there was statistically significant difference.Time-course experiment: after radiating with 3Gy X-ray,real-time fluorescent quantitative polymerase chain reaction(PCR) was used to detect the expression of miR-21 at 0,4,8,12,and 24 hours,there was statistically significant difference.Dose-effect experiment:after radiating the cells with 0,1,2,4,6Gy X ray for 24 hours,the expression of miR-21 was detect by real-time fluorescent quantitative PCR.Results:After transfecting MDA-MB-231 cells with miR-21 mimics,SF increased statistically significantly,compared with normal control group,there was statistically significant difference(P<0.05);after transfecting MDA-MB-231 cells with miR-21 inhibitor,SF decreased statistically significantly,compared with normal control group,there was statistically significant difference(P<0.05);after radiating breast cancer cell line MDA-MB-231 with 3Gy X ray,the expression level of miR-21 was up-regulated,compared with normal control group,there was statistically significant difference(P<0.05),and the expression level of miR-21 peaked at 12 hours,then it returned to the level before radiation;the expression level of miR-21 changed with the dose of radiation,which peaked at the dose of 2 Gy,while the expression level of miR-21 was down-regulated with further increase of dose of radiation,compared with normal control group,there was statistically significant difference(P<0.05),when the does of radiation was 6 Gy,the expression level of miR-21 in breast cancer cell line MDA-MB-231 was statistically significantly lower than in breast cancer cell line MDA-MB-231 without radiation.Conclusion:miR-21 has a certain effect for improving the radiation resistance of breast cancer cell line MDA-MB-231.