Abstract

Background: Abnormal expression of microRNAs (miRNAs) is closely related to glioma, which is one of the most common malignant brain tumors. The current study is to identify the key miRNAs involved in the pathogenesis of glioma and to discover novel therapeutic targets for this disease.

Materials and Methods: Total RNA was extracted from glioma tissues of 100 patients. The microRNA microarray and the northern blot were used to detect the changes of miRNAs expression in 7 pairs of glioma specimens. Relative expressions of miR-23a were validated by real-time reverse transcription polymerase chain reaction (RT-PCR) with specific Taqman probes. In order to evaluate the role of miR-23a, the miR-23a mimics and anti-miR-23a oligonucleotides were transfected to glioma cell lines; the cell proliferation, apoptosis, cell cycle percentage, cell migration and invasion abilities were evaluated in vitro. The target genes of miR-23a were also investigated using the bioinformatics tools. The expression of the apoptotic protease activating factor-1 (APAF1), which might be one of the direct targets of miR-23a, was also analyzed using the luciferase reporter assay and western blot analysis in 293T cells and glioma cell line, respectively.

Results: The microRNA microarray and the northern blot results showed that the expressions of miR-23a in glioma tissues were significantly upregulated. The miR-23a expression levels identified using real time RT-PCR in tumor tissues of 79 samples were higher than in the matched adjacent tissues. By transfection of anti-miR-23a oligonucleotide, the results showed that the proliferation, migration, and invasion of glioma cell lines were significantly suppressed. The bioinformatics searching results showed that APAF1 might be a direct target gene of miR-23a, and it was supported by the luciferase reporter gene assay and western blot analysis results. Finally, experiments showed that overexpression of APAF1 suppressed glioma cell growth and promoted cell apoptosis.

Conclusions: Our findings characterized the expression properties of miR-23a, contributed to the function and molecular mechanism of miR-23a in glioma and implied that miR-23a might be employed as novel prognostic markers and therapeutic targets of glioma.

Keywords: Glioma, miR-23a, apoptotic protease activating factor-1 (APAF1).