MicroRNA-485 inhibits malignant biological behaviour of glioblastoma cells by directly targeting PAK4.

Glioblastoma (GBM), which is characterised by rapid growth, cellular heterogeneity, angiogenesis, extensive invasion, hypoxia and necrosis, is the most common histological subtype of glioma in adults. MicroRNA (miRNA) dysregulation is a common feature of human cancers, including GBM. Previous studies have suggested that miRNAs are a novel class of regulatory molecules in various human cancers. Therefore, miRNAs may be investigated as a novel candidate and screening tool in the clinical diagnosis, therapy and prognosis of GBM. Recent accumulating evidence has demonstrated that miRNA‑485 (miR‑485) is involved in the development and progression of several types of human cancers. However, the expression level, exact role and underlying mechanisms of miR‑485 in GBM remain unclear. In this study, miR‑485 was downregulated in both GBM tissue specimens and cell lines. miR‑485 overexpression inhibited GBM cell proliferation, colony formation, migration and invasion; increased apoptosis in vitro; and reduced tumour growth in vivo. In addition, p21‑activated kinase 4 (PAK4) was demonstrated to be a direct and functional target of miR‑485 in GBM. Furthermore, PAK4 was upregulated in GBM tissues and negatively correlated with miR‑485 expression. Moreover, PAK4 knockdown exhibited a similar effect to miR‑485 overexpression in GBM cells. Enforced expression of PAK4 rescued miR‑485 tumour‑suppressor functions in GBM cells. miR‑485 inhibited the activation of the AKT and ERK signalling pathways in GBM. These results indicate that miR‑485 acts as a tumour suppressor in GBM by, at least partially, directly targeting PAK4 and regulating the AKT and ERK signalling pathways. Thus, miR‑485 may be a potential target for the treatment of patients with GBM.