LncRNA MIR17HG promotes the proliferation, migration, and invasion of retinoblastoma cells by up-regulating HIF-1α expression via sponging miR-155-5p

Long non-coding RNA (lncRNA) miR-17-92a-1 cluster host gene (MIR17HG) is oncogenic in several cancers. This study was aimed to probe into its expression characteristics and biological functions in retinoblastoma (RB) and to explore its role in regulating microRNA-155-5p (miR-155-5p) and hypoxia-inducible factor-1 alpha (HIF-1 alpha). In this study, paired RB samples were collected, and expression levels of MIR17HG, miR-155-5p, and HIF-1 alpha were examined by quantitative real-time polymerase chain reaction (qRT-PCR); the proliferation, migration, and invasion of RB cells were detected by cell counting kit-8 (CCK8) and transwell assays; qRT-PCR and Western blot were used to analyze the changes of miR-155-5p expression and HIF-1 alpha expression. We found that MIR17HG expression was significantly up-regulated in RB samples, which was negatively correlated with miR-155-5p expression. The proliferation, migration, and invasion of RB cells were promoted by MIR17HG overexpression but inhibited by MIR17HG knockdown. MiR-155-5p suppressed the proliferation, migration, and invasion of RB cells. MIR17HG positively regulated the expression of HIF-1 alpha on both mRNA and protein levels in RB cells. Additionally, miR-155-5p was identified as a target of MIR17HG. The data in this study suggest that MIR17HG exerts oncogenic effects in RB via the miR-155-5p/HIF-1 alpha axis.