Steroid receptor coactivator-1 facilitates METTL3-mediated m6A modification by coactivating NF-κB and promotes the malignant progression of glioblastoma

Abstract

Glioblastoma (GBM) is an incurable disease with a poor prognosis. However, the potential impact of steroid receptor coactivator-1 (SRC-1) on N6-methyladenosine (m6A) RNA modification and its role in promoting malignant progression in GBM remain unclear. The relationship between SRC-1 and the m6A “writer” protein, methyltransferase 3 (METTL3), was analyzed using data from the CGGA database. Dot blot and MeRIP‒qPCR were performed to evaluate the effects of SRC-1 knockdown or overexpression on the level of m6A modification in GBM. The biological functions of SRC-1 in regulating METTL3 in GBM were evaluated by assessing its effects on proliferation, migration, cell cycle, colony formation, and apoptosis in vitro and the tumor volume/weight of nude mice xenografted with GBM cells in vivo. Co-IP, immunofluorescence, dual-luciferase, and ChIP‒qPCR assays were subsequently conducted. By analyzing the CGGA database, we determined that SRC-1 has a close positive relationship with METTL3 in GBM. SRC-1 significantly increased the m6A RNA modification level in GBM, SRC-1 knockdown markedly inhibited c-Myc m6A methylation and mRNA stability by suppressing METTL3, and SRC-1 overexpression led to hypermethylation by increasing METTL3. SRC-1 knockdown inhibited the proliferation, migration, apoptosis resistance, and S and G2/M phases of GBM cells in vitro. Mechanically, SRC-1 interacted with the heterodimer of NF-κB p50/p65, whereby p65 activated METTL3 by directly binding to a specific region of its promoter (+18 to +27 bp), thereby increasing the m6A modification of c-Myc and ultimately promoting GBM progression. Importantly, both SRC-1 knockdown and treatment with bufalin, an SRC inhibitor, reduced GBM progression. In conclusion, this study provides the first comprehensive evidence that SRC-1 facilitates GBM progression by binding to NF-κB and regulating METTL3-mediated m6A modification of c-Myc, offering new insights into potential therapeutic strategies for GBM.