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  • Epigenetic Modification of ...
    Ghasemi, Asghar; Mohammadi, Asghar; Fallah, Soudabeh

    Biochemistry (Moscow), 04/2021, Letnik: 86, Številka: 4
    Journal Article

    MicroRNA-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 lower 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 proliferative activity of the U87MG cell line was reduced ( p < 0.01). These findings suggested that DNA methylation has a crucial role in the regulation of miR-219-1 gene expression and that hypermethylated miR-219-1 may be involved in GBM pathogenesis.