Interplay of Epigenetic Reprogramming, Mitochondrial Metabolism, and Dopamine Signalling Pathways Uncovers Metabolic Vulnerabilities in Diffuse Midline Glioma.

Diffuse midline glioma (DMG) is one of the most aggressive paediatric brain tumours and remains almost universally fatal despite decades of research. The defining molecular feature of approximately 80% of DMG tumours is H3K27M, which disrupts PRC2 activity and profoundly remodels chromatin architecture. Increasing evidence suggests that this epigenetic alteration not only rewires transcriptional programs but also influences tumour metabolism. Several studies indicate that H3K27M-mutant tumours exhibit altered mitochondrial metabolism, oxidative phosphorylation activity, redox regulation, and cellular stress responses, although the extent of oxidative phosphorylation dependence varies between models, tumour subtypes, and cellular states. In parallel, dopaminergic signalling has been implicated in cancer stem cell maintenance, metabolic regulation, and tumour survival across multiple malignancies, including glioma. The imipridone compound ONC201/dordaviprone, initially described as a dopamine receptor D2/3 antagonist and subsequently characterised as a mitochondrial ClpP agonist, demonstrates clinical activity in H3K27M-mutant DMG and induces mitochondrial stress responses. In this review, we examine emerging connections between epigenetic dysregulation, mitochondrial metabolism, and dopamine signalling in DMG. We propose that H3K27M-driven epigenetic reprogramming may impose metabolic constraints that increase tumour reliance on mitochondrial bioenergetics and stress-buffering pathways. Within this context, dopamine signalling may function as a metabolic rheostat that contributes to mitochondrial homeostasis; however, this remains a hypothesis requiring direct experimental validation in DMG models. Pharmacologic disruption of this axis may destabilise tumour metabolism and expose therapeutically exploitable vulnerabilities in this otherwise treatment-resistant disease.