miR-10b介导NKG2D调节脑胶质瘤细胞免疫效应的实验研究

Experimental study on regulation of immune effect of brain glioma cells by NKG2D mediated by miR-10b

目的:观察微小核糖核酸-10b(miR-10b)对脑胶质瘤细胞免疫效应的调节作用并探讨其作用机制。方法:取人脑胶质瘤细胞U251进行培养和传代,获得处于对数生长期的细胞。按照1.0×105个/ml浓度制备细胞悬液,并设置对照组、过表达组、低表达组、空白组,每组6个复孔。对照组、过表达组、低表达组分别采用脂质体转染法转染阴性对照、miR-10b模拟物、miR-10b抑制剂,空白组予以等量无菌生理盐水。分离和培养1例健康志愿者外周血自然杀伤(NK)细胞。MTT法检测不同效靶比时NK细胞的杀伤活性;流式细胞仪检测各组NK细胞表面NK细胞激活受体(NKG2D)表达,并检测各组人脑胶质瘤细胞U251表面主要组织相容性复合物Ⅰ链相关基因A(MICA)、UL16结合蛋白2(ULBP2)、UL16结合蛋白3(ULBP3)表达。结果:对照组、过表达组、低表达组转染效率分别为(93.55±2.05)%、(95.67±3.14)%、(94.18±3.26)%;与对照组和空白组相比,过表达组miR-10b表达升高,低表达组miR-10b表达降低,差异均有统计学意义(P<0.05),且对照组和空白组miR-10b表达差异无统计学意义(P>0.05);与对照组和空白组相比,过表达组NK细胞不同效靶比杀伤活性均降低、NKG2D表达降低,低表达组NK细胞不同效靶比杀伤活性均增高、NKG2D表达增高,差异均有统计学意义(P<0.05),各组NK细胞杀伤活性均随效靶比增加而增高,差异均有统计学意义(P<0.05),且对照组与空白组相比,相同效靶比NK细胞杀伤活性、NKG2D表达差异均无统计学意义(P>0.05);与对照组和空白组相比,过表达组人脑胶质瘤细胞U251表面MICA、ULBP2、ULBP3表达均降低,低表达组人脑胶质瘤细胞U251表面MICA、ULBP2、ULBP3表达均增高,差异均有统计学意义(P<0.05),且对照组与空白组人脑胶质瘤细胞U251表面MICA、ULBP2、ULBP3表达差异均无统计学意义(P>0.05)。结论:抑制miR-10b表达能够增加NK细胞表面NKG2D和人脑胶质瘤细胞U251表面MICA、ULBP2、ULBP3表达,增强NK细胞对人脑胶质瘤细胞U251的杀伤活性。

Objective:To observe the regulatory effect of microRNA-10b(miR-10b)on the immune effect of glioma cells and explore its mechanism.Methods:Human glioma cell U251 was cultured to obtain cells in logarithmic growth stage.The cell suspen-sion was prepared according to the concentration of 1.0×105 cells/ml,and the control group,overexpression group,low expression group and blank group were set up,with 6 wells in each group.The negative control,miR-10b mimics and miR-10b inhibitor were transfected by liposome transfection in control group,overexpression group and low expression group,respectively.The blank group was given the same amount of sterile normal saline.Natural killer(NK)cells from peripheral blood of a healthy volunteer was isolated and cultured.The killing activity of NK cells was detected by MTT method.The expression of NK cell activated receptor(NKG2D)on the surface of NK cells in each group were detected by flow cytometry,and the expression of major histocompatibility complex classⅠchain-related gene A(MICA),UL16 binding protein 2(ULBP2)and UL16 binding protein 3(ULBP3)on the surface of U251 hu-man glioma cells in each group were detected.Results:The transfection efficiency of control group,overexpression group and low ex-pression group were(93.55±2.05)%,(95.67±3.14)%,(94.18±3.26)%,respectively.Compared with control group and blank group,the expression of miR-10b increased in overexpression group and decreased in low expression group,and the difference were statisti-cally significant(P<0.05).There was no significant difference in the expression of miR-10b between control group and blank group(P>0.05).Compared with control group and blank group,the killing activity of NK cells with different effect target ratios in overex-pression group decreased,the expression of NKG2D decreased,the killing activity of NK cells with different effect target ratios in low expression group increased,and the expression of NKG2D increased,and the difference were statistically significant(P<0.05).The killing activity of NK cells in each group increased with the increase of effect target ratio,and the difference were statistically signifi-cant(P<0.05),and there was no significant difference in NK cell killing activity and NKG2D expression between control group and blank group(P>0.05).Compared with control group and blank group,the expression of MICA,ULBP2 and ULBP3 on the surface of human glioma cell U251 in overexpression group decreased,and the expression of MICA,ULBP2 and ULBP3 on the surface of human glioma cell U251 in low expression group increased,the difference were statistically significant(P<0.05),and there was no signifi-cant difference in the expression of MICA,ULBP2 and ULBP3 on the surface of U251 glioma cells between control group and blank group(P>0.05).Conclusion:Inhibiting the expression of miR-10b can increase the expression of NKG2D on the surface of NK cells and MICA,ULBP2 and ULBP3 on the surface of human glioma cell U251,and enhance the killing activity of NK cells against human glioma cell U251.