Long non-coding RNA NEAT1 regulates glioma cell proliferation and apoptosis by competitively binding to microRNA-324-5p and upregulating KCTD20 expression

Previous studies have demonstrated that long non-coding RNAs (lncRNAs) serve a key role in the development and progression of several types of cancer, including glioma. The lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) contributes to cancer growth through its effects on cell proliferation, migration, invasion and drug resistance. However, the exact regulatory mechanisms via which NEAT1 acts in glioma are unclear. In the present study, the expression levels and function of NEAT1 in glioma tissues and cell lines were examined in vitro and in vivo. By reverse transcription-quantitative PCR and fluorescence in situ hybridization analysis, NEAT1 expression was upregulated in glioma tissues compared with in adjacent normal brain tissues, and elevated NEAT1 levels were associated with poor prognosis. Cell Counting Kit-8, colony formation, ethynyldeoxyuridine, flow cytometry and western blotting assays were performed to detect the effects of NEAT1 on cell biological behavior. Knockdown of NEAT1 in glioma cell lines was associated with cell cycle arrest at the G(0)/G(1) phase, decreased proliferation and elevated apoptosis in vitro, and resulted in reduced tumor growth and increased survival in a mouse xenograft model of glioma. Using bioinformatics analysis, RNA immunoprecipitation experiments and luciferase reporter assays, it was demonstrated that NEAT1 may competitively bind to microRNA (miR)-324-5p, thus blocking its interaction with target mRNAs. Potassium channel tetramerization protein domain containing 20 (KCTD20) was identified as a specific miR-324-5p target. Accordingly, the inhibition of NEAT1 resulted in the downregulation of KCTD20 through competitive binding with miR-324-5p, decreased cell proliferation and increased apoptosis. Concomitant NEAT1 knockdown and inhibition of miR-324-5p partially reversed the effects of NEAT1 knockdown on cell proliferation and apoptosis, and further regulated KCTD20 expression. Collectively, the present findings demonstrated that NEAT1 acted as a competing endogenous RNA for miR-324-5p, and identified the NEAT1/miR-324-5p/KCTD20 axis as a novel regulatory axis and a potential therapeutic target for human glioma.