Radiotherapy Reshapes the 3D Genome in Medulloblastoma Cells

Radiotherapy is central to medulloblastoma treatment, yet the molecular and three-dimensional (3D) genome responses to irradiation remain poorly understood. Here, we integrated RNA sequencing, proteomics, and Micro-C to characterise the response of ONS-76 medulloblastoma cells to clinically relevant radiation exposures. A single 2 Gy dose induced widespread transcriptional and proteomic changes, including altered cell adhesion, migration, DNA replication, and ribosome biogenesis pathways. Integrated analysis identified LAMB3 and AKR1B10 as candidate mediators of radioresponse that remained elevated following fractionated irradiation. Micro-C profiling following single and repeated 2 Gy exposures revealed radiation-induced 3D genome remodelling. While global genome organisation remained largely stable, irradiation promoted shifts towards active A compartments, new TAD boundary formation, and transient boundary strengthening. Together, these findings provide the first genome-wide characterisation of radiation-induced 3D chromatin reorganisation in a medulloblastoma model and identify molecular and structural features associated with radioresponse.