ID #427 Delineating the epigenetic landscape of childhood glioblastoma for targeted therapy

Abstract

Paediatric high-grade glioma (pHGG) represents one of the most lethal childhood brain tumours, with particularly poor outcomes in children under five years of age. Despite advances in molecular classification, effective targeted therapies remain limited. Emerging evidence suggests that epigenetic dysregulation, including aberrant DNA methylation, plays a central role in pHGG tumour progression, invasion, and treatment resistance. This study aimed to identify prognostically relevant differentially methylated genes (DMGs) in pHGG and to evaluate the therapeutic potential of targeting these differentially methylated signalling pathways.

Genome-wide DNA methylation profiling was performed using Illumina EPIC array datasets from paediatric HGG cohorts. Prognostically significant DMGs were identified through computational analyses with over 180 genes significantly different (P < 0.001) between healthy brain tissues and HGG samples. Gene Ontology and pathways analysis revealed upregulated signalling pathways with lipid metabolism, glycolysis, cell cycle and aurora kinanse signalling as highly regulated. Furthermore, computational analyses identified a subset of DMGs strongly associated with patient survival and enriched in epigenetic regulatory pathways, including chromatin modification and transcriptional repression. Functional validation was conducted using in vitro HGG cell models were several repurposed compounds targeting these signalling pathways demonstrated significant anti-tumour activity in both paediatric and adult HGG cell lines, with no detectable toxicity in non-cancerous controls. Treatments resulted in a significant reduction in cell viability (p < 0.05) and a marked inhibition of tumour invasion and metastatic (p < 0.001). Mechanistically, these effects were associated with suppression of EZH2-mediated epigenetic signalling, and tumour inhibition occurred predominantly through reduced invasive capacity rather than induction of apoptosis, highlighting a distinct therapeutic mechanism relevant to inoperable and highly infiltrative disease.

Together, these findings identify prognostic relevance of analysing methylation biomarkers in pHGG and support the repurposing of novel drugs as a promising strategy to limit tumour invasion and progression, offering novel therapeutic avenues for managing aggressive and metastatic paediatric gliomas.