The Role of miRNAs in Gliomas in Response to Hypoxia

AIMS Identifying significant miRNAs that are either under or overexpressed in hypoxia compared to normoxia in glioma cells. Further exploring the effect and role of hypoxia on miR-92a-3p and miR-149-5p in gliomas in apoptotic and cellular senescence pathways. METHOD A range of glioma cells were used for screening, including primary cell lines: GIN28 and GIN31; low-grade cell lines: LGG19 and LGG24; a paediatric cell line: SF188 and a commercially available glioblastoma cell line U87. These cells were cultured at both 1% (hypoxia) and 20% (normoxia) oxygen levels. Screening of miRNAs was achieved by quantitative polymerase chain reaction (qPCR) using miRNA specific primers. Knockdowns/in were achieved by transfecting with miR-92a-3p and miR-149-5p mimics and inhibitors. Caspase-glo assay was used to assess the effect of hypoxia on apoptosis. RESULTS A range of miRNAs were differentially expressed in hypoxia in a range of glioma cell lines. miRNA 92a-3p and miR-149-5p were found to be downregulated and upregulated respectively in primary gliomablastoma cells in hypoxia compared to normoxia. These particular miRNAs are also found to have multiple targets in apoptosis and cellular senescence. CONCLUSION The screening of 90 miRNAs among the different categories of gliomas highlighted multiple miRNAs that were significant in hypoxia compared to normoxia. Using primary cell lines have identified hypoxia-affected miRNAs in glioblastomas. This discovery will increase our knowledge and understanding of the hypoxia effect on miRNAs which may aid and direct targeted therapy to conquer hypoxia in glioblastomas.