Epigenetic Modification of MicroRNA-219-1 and Its Association with Glioblastoma Multiforme

AbstractMicroRNA-219-1 (miR-219-1) acts as a tumor suppressor in a variety of cancers but, the regulatory epigenetic mechanism involved in its gene expression level has not been studied. Using real-time polymerase chain reaction (real-time PCR) and bisulfite genomic sequencing technology, promoter methylation level of miR-219-1 and gene expression levels of miR-219-5p and miR-219-1-3p were determined respectively, in glioblastoma multiforme (GBM) (n = 31), their adjacent normal tissues (n = 31), and GBM U87 cell line. Following treatment of GBM U87 cells with 5-aza-2 ′-deoxycitidine (5-aza-dC), miR-219-1 promoter methylation, their target mRNA, and protein levels were determined by genomic bisulfite modification, real-time-PCR, and ELISA techniques, respectively. Our results showed that gene expression levels of miR-219-5p and miR-219-1-3p were significantly l ower in GBM patients relative to their adjacent normal tissues (p< 0.01). MiR-219-1 promoter had a high level of methylation in GBM tissues (p< 0.01) and a negative correlation was observed between the miRNAs gene expression and methylation levels in GBM tissues (p< 0.01). Treatment of GBM U87 cells by 5-aza-dC decreased the level of miR-219-1 methylation, amount of target mRNA, and levels of cyclin A2 and mucin 4 (MUC4) proteins, and increased the expression levels of miR-219-5p and miR-219-1-3p (p< 0.01). Using external miR-219-5p and miR-219-1-3p, the expression of cyclin A2 and MUC4 were suppressed and...
Source: Biochemistry (Moscow) - Category: Biochemistry Source Type: research