DNAR-11. CHARACTERIZING THE GENOMIC CONSEQUENCES OF G-QUADRUPLEX STABILIZATION IN ATRX-DEFICIENT HIGH-GRADE GLIOMA

Abstract α-thalassaemia/mental retardation X-linked (ATRX) mutations are a critical molecular marker for high-grade glioma (HGG). These lead to accumulations of abnormal DNA secondary G-quadruplex (G4) structures, thereby inducing replication stress and damage. As G4s arise at GC-rich regions (i.e., pericentromeric telomeric regions), ATRX-deficiency alters genome-wide accessibility chromatin causes transcriptional dysregulation. However, the genomic consequences this in context poorly understood. Our goal is target ATRX deficiency through G4 stabilizers, class novel small molecule compounds that selectively bind stabilize G4s. Using combination functional experiments such as cell viability, western blot, flow cytometry, RNA-sequencing (RNA-seq), immunofluorescence (IF), we evaluated mechanisms drive selective lethality upon stabilization. Patient-derived stem cells (GSCs) were treated with either vehicle (DMSO) or varying doses CX-5461 (G4 stabilizer, Senhwa Biosciences). Excitingly, ATRX-deficient GSCs demonstrate dose-dependent enhanced sensitivity stabilization, compared ATRX-intact controls. Cell viability assays confirmed specificity comparison other commercially used stabilizers. stabilization activated p53-independent apoptosis exhibited G2/M arrest and, interestingly, upregulated expression both ATR ATM pathways, indicating damage, respectively. IF staining induction damage markers 53BP1 gH2AX. preliminary findings suggest activation leads Cyclin D1 degradation inhibition transcription factor NF-κB, driving apoptosis. In fact, RNA-seq analyses revealed positive enrichment apoptosis, repair, NF-κB pathways negative checkpoint CX-5461. work defines action efficacy therapeutic strategy pre-clinical HGG models, strong implications cancers potential translation into clinical practice.