microRNA‑188 acts as a tumour suppressor in glioma by directly targeting the IGF2BP2 gene.

Glioma is the most common and aggressive human brain tumour and accounts for ~35‑61% of intracranial tumours. Despite considerable advances in treatments for glioma, the prognosis for patients with this disease remains unsatisfactory. MicroRNAs (miRNAs of miRs) are small regulatory RNA molecules that have been identified as being involved in the initiation and progression of human cancers, and represent novel therapeutic targets for anticancer treatments. The dysregulation of miR‑188 has been reported in various kinds of human cancer. However, its expression pattern, biological roles and potential mechanism in glioma remain unknown. Expression levels of miR‑188 in glioma tissues and cell lines were detected through reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). Cell Counting Kit-8 assays and migration and invasion assays were used to explore the effects of miR‑188 on the proliferation, migration and invasion of glioma cells, respectively. Bioinformatics analysis and luciferase reporter assays were performed to examine insulin‑like growth factor 2 mRNA-binding protein 2 (IGF2BP2) as a target gene of miR‑188. RT‑qPCR and Spearman's correlation analysis were then performed to measure IGF2BP2 mRNA expression in clinical glioma tissues and its correlation with miR‑188 expression. The regulatory effect of miR‑188 on IGF2BP2 expression was also investigated through RT‑qPCR and western blotting analysis. Finally, the biological roles of IGF2BP2 in glioma cells were assessed. miR‑188 levels were significantly reduced in glioma tissues and cell lines compared with adjacent normal tissues and normal human astrocytes, respectively. In addition, miR‑188 overexpression suppressed cell proliferation, migration and invasion of glioma. The present study identified IGF2BP2 as a direct target of miR‑188 in glioma, and IGF2BP2 under‑expression served tumour‑suppressive roles in glioma growth and metastasis. Thus, miR‑188 had a similar role in glioma by inhibiting the action of its downstream target, IGF2BP2. Therefore, miR‑188 may be a potential therapeutic target for the prevention and treatment of patients with glioma.