Department of Neurosurgery, Jinshan Hospital Affiliated to Fudan University, Shanghai, China.
Bosn J Basic Med Sci. 2022 Apr 1;22(2):205-216. doi: 10.17305/bjbms.2021.6028.
Circular RNA (circRNA) is a key regulator of tumor progression. However, the role of circFOXM1 in glioblastoma (GBM) progression is unclear. The aim of this study was to investigate the role of circFOXM1 in GBM progression. The expression levels of circFOXM1, miR-577, and E2F transcription factor 5 (E2F5) were examined by real-time quantitative polymerase chain reaction. Cell counting kit 8 assay, EdU staining, and transwell assay were used to detect cell proliferation, migration, and invasion. The levels of glutamine, glutamate, and α-ketoglutarate were determined to evaluate the glutaminolysis ability of cells. Protein expression was tested by Western blot analysis. Dual-luciferase reporter assay, RNA pull-down assay, and RNA immunoprecipitation assay were employed to verify the interaction between miR-577 and circFOXM1 or E2F5. Mice xenograft model for GBM was constructed to perform in vivo experiments. Our results showed that circFOXM1 was highly expressed in GBM tumor tissues and cells. Silencing of cir FOXM1 inhibited GBM cell proliferation, migration, invasion, glutaminolysis, as well as tumor growth. MiR-577 could be sponged by circFOXM1, and its inhibitor could reverse the suppressive effect of circFOXM1 downregulation on GBM progression. E2F5 was a target of miR-577, and the effect of its knockdown on GBM progression was consistent with that of circFOXM1 silencing. CircFOXM1 positively regulated E2F5 expression, while miR-577 negatively regulated E2F5 expression. In conclusion, our data confirmed that circFOXM1 could serve as a sponge of miR-577 to enhance the progression of GBM by targeting E2F5, which revealed that circFOXM1 might be a biomarker for GBM treatment.
环状 RNA（circRNA）是肿瘤进展的关键调节因子。然而，circFOXM1 在神经胶质瘤（GBM）进展中的作用尚不清楚。本研究旨在探讨 circFOXM1 在 GBM 进展中的作用。通过实时定量聚合酶链反应检测 circFOXM1、miR-577 和 E2F 转录因子 5（E2F5）的表达水平。使用细胞计数试剂盒 8 检测细胞增殖、迁移和侵袭，使用 EdU 染色和 Transwell 检测。测定谷氨酰胺、谷氨酸和α-酮戊二酸的水平以评估细胞的谷氨酰胺分解能力。通过 Western blot 分析检测蛋白表达。双荧光素酶报告基因检测、RNA 下拉检测和 RNA 免疫沉淀检测用于验证 miR-577 与 circFOXM1 或 E2F5 之间的相互作用。构建 GBM 小鼠异种移植模型进行体内实验。结果显示，circFOXM1 在 GBM 肿瘤组织和细胞中高表达。沉默 circFOXM1 抑制 GBM 细胞增殖、迁移、侵袭、谷氨酰胺分解以及肿瘤生长。miR-577 可以被 circFOXM1 海绵化，其抑制剂可以逆转 circFOXM1 下调对 GBM 进展的抑制作用。E2F5 是 miR-577 的靶标，其敲低对 GBM 进展的影响与 circFOXM1 沉默一致。circFOXM1 正向调节 E2F5 表达，而 miR-577 负向调节 E2F5 表达。总之，我们的数据证实 circFOXM1 可以作为 miR-577 的海绵体，通过靶向 E2F5 增强 GBM 的进展，这表明 circFOXM1 可能是 GBM 治疗的生物标志物。
