Long non-coding RNA RP5-833A20.1 inhibits proliferation, metastasis and cell cycle progression by suppressing the expression of NFIA in U251 cells

Early reports suggest that nuclear factor IA (NFIA) is important in the pathogenesis of glioma. Our previous study demonstrated that the long non-coding RNA (lncRNA), RP5-833A20.1, suppressed the expression of NFIA in THP-1 macrophage-derived foam cells. However, the effect and possible mechanism of RP5-833A20.1 on glioma remains to be fully elucidated, and whether the NFIA-dependent pathway is involved in its progression has not been investigated. In the present study, the mechanisms by which RP5-833A20.1 regulates the expression of NFIA in glioma were investigated. The expression levels of RP5-833A20.1 and NFIA were determined in U251 cells and clinical samples using reverse transcription-quantitative polymerase chain reaction (PCR) analysis. The effects of RP5-833A20.1 on cell proliferation, invasion, cell cycle and apoptosis were evaluated using in vitro assays. The potential changes in protein expression were investigated using western blot analysis. The methylation status of the CpG island in the NFIA promoter was determined using bisulfite PCR (BSP) sequencing. It was found that the expression of RP5-833A20.1 was downregulated, whereas the expression of NFIA was upregulated in glioma tissues, compared with corresponding adjacent nontumor tissues from 20 patients with glioma. The overexpression of RP5-833A20.1 inhibited proliferation and cell cycle progression, and induced apoptosis in the U251 cells. The mRNA and protein levels of NFIA were markedly inhibited by overexpression of RP5-833A20.1 in the U251 cells. The overexpression of RP5-833A20.1 increased the expression of microRNA-382-5p in the U251 cells. The BSP assay revealed that the overexpression of RP5-833A20.1 enhanced the methylation level of the NFIA promoter. These results demonstrated that RP5-833A20.1 inhibited tumor cell proliferation, induced apoptosis and inhibited cell-cycle progression by suppressing the expression of NFIA in U251 cells. Collectively, these results indicated RP5-833A20.1 as a novel therapeutic target for glioma.