Epigenetic upregulation of FGF2 promotes glioblastoma progression by enhancing the Warburg effect

Abstract

Glioblastoma (GBM), the most common primary intracranial malignancy, remains poorly understood in terms of its underlying etiology. Although fibroblast growth factor 2 (FGF2) is highly expressed in GBM, its epigenetic regulation and functional contributions to disease progression are incompletely defined. Here, through integrated bioinformatics analysis, real-time PCR, and western blot, we demonstrate that FGF2 expression is significantly upregulated in GBM patient-derived tissues and cells. Functional assays revealed that silencing FGF2 markedly suppressed GBM cell proliferation and migration in vitro. Mechanistically, we identified cyclic AMP response element-binding protein 1 (CREB1) as a critical transcription factor regulating FGF2 transcription through binding to cAMP response elements (CREs) within the FGF2 gene's silencer I and core promoter regions. Intriguingly, these CREs exerted opposing regulatory effects: hypermethylation of the silencer I and hypomethylation of the core promoter favored preferential CREB1 binding to the core promoter in GBM cells. CREB1 recruitment of histone acetyltransferase CBP further promoted histone H3K27 acetylation and enhanced chromatin accessibility at the FGF2 core promoter, thereby driving transcriptional activation. Additionally, FGF2 has been shown to significantly enhance glycolysis and lactate production in GBM cells, fueling malignant growth. Collectively, our findings highlight the CREB1/FGF2/lactate axis as a promising therapeutic target for GBM treatment.