下调miR-183靶向肿瘤抑制因子CPEB1增强脑胶质瘤细胞的 放射敏感性

目的：探讨 miR-183 对脑胶质瘤细胞放射敏感性的影响。方法：2020 年 10 月至 2021 年 6 月，收集秦皇岛市第一医院 40 例脑胶质瘤组织标本，对 T98G 细胞进行梯度剂量 X 射线（0、2、4、6 Gy）照射。采用 qPCR 检测 miR-183、细胞质多腺苷酸化元件结合蛋白 1（cytoplasmic polyadenylation element-binding protein 1，CPEB1）在脑胶质瘤组织、T98G 细胞和经 X 射线照射的 T98G 细胞中的表达量。将 miR-183 inhibitor 转染 T98G 细胞后下调 miR-183 表达，经 6 Gy X 射线垂直照射，CCK-8 法、流式细胞术和 WB 法，分别检测 T98G 细胞增殖能力、细胞凋亡率及 BAX 和 Bcl2 蛋白表达量。Targetscan 软件预测和双荧光素酶报告基因实验检测 miR-183 与 CPEB1 的靶向关系。下调 CPEB1 表达后，经 6 Gy X 射线照射，分别用 CCK-8 法、流式细胞术和 WB 法检测 T98G 细胞增殖能力、细胞凋亡率及 BAX 和 Bcl2 蛋白表达量。将 pcDNA-CPEB1 或 CPEB1 siRNA 质粒转染T98G 细胞，分别下调或过表达 CPEB1 后，检测 miR-183 通过 CPEB1 对 T98G 细胞放射敏感性的影响。结果：脑胶质瘤组织和细胞中 miR-183 呈高表达，CPEB1 mRNA 呈低表达。T98G 细胞中 miR-183 的表达量随着 X 射线放射剂量增加而降低（P<0.05），CPEB1 表达量随着 X 射线放射剂量增加而升高（P<0.05）。6 Gy X 射线照射 T98G 细胞后，下调 miR-183 可降低细胞增殖能力、增加细胞凋亡率，而过表达 miR-183 则起到相反作用（P<0.05）。miR-183 靶向 CPEB1 mRNA 且负调控 CPEB1 表达。下调 CPEB1 表达后，经 6 Gy X 射线照射可显著提高 T98G 细胞增殖能力（P<0.05）、降低细胞凋亡率（P<0.05），miR-183 可逆转 CPEB1 过表达对细胞 T98G 放射敏感性的促进作用（P<0.05）。结论：下调 miR-183 的表达能够负调控 CPEB1，从而增强脑胶质瘤细胞的放射敏感性。

Down-regulation of miR-183 targeted tumor suppressor CPEB1 enhances radiosensitivity of glioma cells

Objective: To investigate the effect of miR-183 on radiosensitivity of glioma cells.Methods: From October 2020 to June 2021, tissue samples of 40 cases of brain glioma from the First Hospital of Qinhuangdao were collected. T98G cells were irradiated with gradient dose X-ray (0, 2, 4, 6 Gy). The expression of miR-183 and CPEB1 in glioma tissues, T98G cells and X-ray irradiated T98G cells were detected by qPCR. After transfection of T98G cells with miR-183 inhibitor, the expression of miR-183 was down-regulated. The proliferation ability, apoptosis rate, BAX and Bcl2 protein expression of T98G cells were detected by CCK-8 assay, flow cytometry and WB, respectively, after 6 Gy X-ray vertical irradiation. The targeting relationship between miR-183 and CPEB1 was detected by Targetscan software prediction and dual luciferase reporter gene assay. After down regulating the expression of CPEB1, after 6 Gy X-ray irradiation, the proliferation ability, apoptosis rate, BAX and Bcl2 protein expression of T98G cells were detected by CCK-8 assay, flow cytometry and WB, respectively. T98G cells were transfected with pcDNA-CPEB1 or CPEB1 siRNA plasmid, and after CPEB1 was down-regulated or overexpressed, respectively, the effect of miR-183 on radiosensitivity of T98G cells through CPEB1 was detected.Results: The expression of miR-183 in glioma tissues and cells increased significantly, and the expression of CPEB1 mRNA decreased significantly. The expression of miR-183 in T98G cells decreased with the increase of X-ray radiation dose (P<0.05), and the expression of CPEB1 increased with the increase of X-ray radiation dose (P<0.05). After 6 Gy X-ray irradiation of T98G cells, down-regulation of miR-183 could reduce cell proliferation and increase apoptosis rate, while overexpression of miR-183 had the opposite effect (P<0.05).MiR-183 targeted mRNA CPEB1 and negatively regulated CPEB1 expression. After down-regulation of CPEB1, 6 Gy X-ray irradiation could significantly improve the proliferation of T98G cells (P<0.05) and reduce the apoptosis rate (P<0.05). MiR-183 could reverse the promoting effect of CPEB1 overexpression on radiosensitivity of T98G cells (P<0.05). Conclusion: Down-regulation of miR-183 expression can negatively regulate CPEB1, which might enhance the radiosensitivity of glioma cells.