中文摘要：

目的观察miR-15b对人胶质瘤细胞株A172细胞增殖和凋亡的影响，并探讨其对RAS／MEK／ERK1／2信号通路的作用。方法合成miR-15b寡聚核甘酸拟似物（miR-15b mimics）转染A172细胞株，应用噻唑蓝细胞增殖试验（MTT）、流式细胞术评价miR-15b对A172细胞增殖和凋亡的作用，以Western blot法检测miR-15b对RAS及其下游信号通路的影响。结果转染miR-15b mimics后，应用实时定量PCR检测空白对照组、阴性对照组、miR-15 bmimics组的△Ct值分别为15．25±1．12、15．92±0．98和10．58±0．87，提示miR-15b在A172细胞中表达水平明显升高。Western blot结果显示，miR-15b mimics可显著抑制RAS、MEK、ERK1／2及pERK1／2蛋白的表达水平（均P〈0．05）。MTT法检测结果显示，miR-15b mimics转染A172细胞24h、48h、72h后，细胞相对存活率分别为（72．28±6．52）％、（61．86±5．79）％和（59．38±5．97）％；miR-15b mimics组的细胞存活率较空白对照组和阴性对照组明显下降（P〈0．05）。细胞周期分析发现，miR-15b mimics组细胞G1／G0期为66．84％，miR-15b mimics诱导A172细胞阻滞在G0／G1期。磷脂结合蛋白／碘化丙啶（Annexin V／PI）双染法检测显示，空白对照组、阴性对照组、miR-15b mimics组的细胞凋亡率分别为（2．7±0．83）％、（2．5±0．81）％和（18．2±1．58）％；miR-15b mimics组A172细胞凋亡率较空白对照组和阴性对照组明显升高（P〈0．05）。结论miR-15b可显著抑制胶质瘤细胞的增殖，并促进细胞凋亡。miR-15b针对RAS／MEK／ERK1／2信号通路的靶向治疗有望成为胶质瘤治疗的新途径。

英文摘要：

Objectives To observe the effect of miR-15b on proliferation and apoptosis of human glioma cell line A172 and to investigate its role in RAS/MEK/ERK1/2 signaling pathway cells. Methods The synthetic miR-15b mimics transfected the A172 cell line. Methylthiazol tetrazoliu （MTT） assay and flow cytometry were used to assess the effects of miR-15b on A172 cell proliferation and apoptosis. Western blotting assay was used to detect the effect of miR-15b on RAS and its downstream signaling pathways. Results After transfecting miR-15b mimics, real-time quantitative PCR was use to detect the ACt values in the blank control group, the negative control group, the miR-15b mimics group, and they were 15.25 ± 1.12, 15.92 ±0. 98, and 10. 58 ± 0. 87, respectively, suggesting the expression level of miR-15b in the A172 cells increased significantly. Western blot results showed that miR-15b mimics significantly inhibited the expression levels of RAS, MEK, ERK1/2, and pERK1/2 protein （all P 〈 0. 05）. The test results of MTT assay showed that relative survival rates of cells were 72.28 ± 6. 52%, 61.86 ±5.79%, and 59. 38± 5.97%, respectively at 24, 4g, and 72 h after the A172 cells being transfected by miR-15b mimics. The cell survival rate of the miR-15b mimics group was decreased significantly compare with the blank control group and the negative group （ P 〈 0. 05 ）. The cell cycle analysis revealed that the cell G1/G0 phase of miR- 15b mimics group was 66. 84%. The miR-15b mimics induced A172 cell block was at G1/G0 phase. The detection of annexin/propidium iodide （ Annexin V/PI） double staining showed that the cell apoptosis rates of the blank control group, the negative control group, and the miR-15b mimics group were 2. 7 ±0. 83% , 2. 5 ±0. 81% , and 18.2 ±1.58% , respectively. The A172 cell apoptosis rate of the miR-15b mimics group increased significantly compare with the blank control group and the negative control group （ P 〈 0. 05 ）. Conclusions miR-15b can inhibit the proliferation of gli