Objective: This study aimed to elucidate the molecular mechanism underlying the involvement of abnormal DNA methylation in the development of glioma and identify potential new targets for glioma therapy.
Methods: The GSE79122 chip achieved from the Gene Expression Omnibus (GEO) database containing 69 glioma samples and 9 normal samples was analyzed. Methylation-specific polymerase chain reaction (MS-PCR or MSP), reverse transcription-PCR, and Western blot analysis were used to confirm the methylation level and expression level of the interleukin receptor-associated kinase (IRAK3 ) gene in glioma cells, 36 glioma samples, and the corresponding normal samples. In vitro, the proliferation, apoptosis rate, migration, and invasion abilities of glioma cells were detected by Cell Counting Kit-8 assay, Transwell assay, enzyme-linked immunosorbent assay, and flow cytometry, respectively. Besides, the xenograft assay of nude mice was used to confirm the effect of the IRAK3  on glioma in vivo.
Results: Microarray analysis showed that the IRAK3  was one of the most hypermethylated genes in glioma, and the related mitogen-activated protein kinase (MAPK) signaling pathway was activated. More experiments supported the higher methylation level and lower expression level of the IRAK3  in glioma tissues and cell lines. The viability, migration, and invasion ability of glioma cells significantly reduced and the apoptosis rate increased with the overexpression and demethylation of the IRAK3  in vitro. Besides, treatment with the MAPK signaling pathway inhibitor PD325901 alone or the overexpression or demethylation of the IRAK3  had a similar effect as the overexpression or demethylation of the IRAK3  alone in glioma cells. In vivo, xenotransplantation experiments in nude mice confirmed that the overexpression and demethylation of the IRAK3  and suppression of the MAPK signaling pathway inhibited the development of glioma.
Conclusion: IRAK3  inhibited the development of glioma progression through the MAPK signaling pathway.
Keywords: glioma, IRAK3 , MAPK signaling pathway, methylation