Histone 3 lysine27-to-methionine (H3-K27M) mutations most frequently occur in diffuse midline gliomas (DMGs) of the childhood pons but are also increasingly recognized in adults. Their potential heterogeneity at different ages and midline locations is vastly understudied. Here, through dissecting the single-cell transcriptomic, epigenomic and spatial architectures of a comprehensive cohort of patient H3-K27M DMGs, we delineate how age and anatomical location shape glioma cell-intrinsic and -extrinsic features in light of the shared driver mutation. We show that stem-like oligodendroglial precursor-like cells, present across all clinico-anatomical groups, display varying levels of maturation dependent on location. We reveal a previously underappreciated relationship between mesenchymal cancer cell states and age, linked to age-dependent differences in the immune microenvironment. Further, we resolve the spatial organization of H3-K27M DMG cell populations and identify a mitotic oligodendroglial-lineage niche. Collectively, our study provides a powerful framework for rational modeling and therapeutic interventions.

• MeSH
• dítě MeSH
• gliom * genetika   MeSH
• histony genetika   MeSH
• lidé MeSH
• methionin MeSH
• mutace MeSH
• nádorové mikroprostředí genetika   MeSH
• Racemethionin MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• histony MeSH
• methionin MeSH
• Racemethionin MeSH

Diffuse midline gliomas (DMGs) bearing driver mutations of histone 3 lysine 27 (H3K27M) are incurable brain tumors with unique epigenomes. Here, we generated a syngeneic H3K27M mouse model to study the amino acid metabolic dependencies of these tumors. H3K27M mutant cells were highly dependent on methionine. Interrogating the methionine cycle dependency through a short-interfering RNA screen identified the enzyme methionine adenosyltransferase 2A (MAT2A) as a critical vulnerability in these tumors. This vulnerability was not mediated through the canonical mechanism of MTAP deletion; instead, DMG cells have lower levels of MAT2A protein, which is mediated by negative feedback induced by the metabolite decarboxylated S-adenosyl methionine. Depletion of residual MAT2A induces global depletion of H3K36me3, a chromatin mark of transcriptional elongation perturbing oncogenic and developmental transcriptional programs. Moreover, methionine-restricted diets extended survival in multiple models of DMG in vivo. Collectively, our results suggest that MAT2A presents an exploitable therapeutic vulnerability in H3K27M gliomas.

• MeSH
• epigenom MeSH
• gliom * genetika   MeSH
• histony genetika   MeSH
• methionin genetika   MeSH
• methioninadenosyltransferasa metabolismus   MeSH
• myši MeSH
• nádory mozku * genetika   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• histony MeSH
• Mat2a protein, mouse MeSH Prohlížeč
• methionin MeSH
• methioninadenosyltransferasa MeSH

Histone H3.3 glycine 34 to arginine/valine (G34R/V) mutations drive deadly gliomas and show exquisite regional and temporal specificity, suggesting a developmental context permissive to their effects. Here we show that 50% of G34R/V tumors (n = 95) bear activating PDGFRA mutations that display strong selection pressure at recurrence. Although considered gliomas, G34R/V tumors actually arise in GSX2/DLX-expressing interneuron progenitors, where G34R/V mutations impair neuronal differentiation. The lineage of origin may facilitate PDGFRA co-option through a chromatin loop connecting PDGFRA to GSX2 regulatory elements, promoting PDGFRA overexpression and mutation. At the single-cell level, G34R/V tumors harbor dual neuronal/astroglial identity and lack oligodendroglial programs, actively repressed by GSX2/DLX-mediated cell fate specification. G34R/V may become dispensable for tumor maintenance, whereas mutant-PDGFRA is potently oncogenic. Collectively, our results open novel research avenues in deadly tumors. G34R/V gliomas are neuronal malignancies where interneuron progenitors are stalled in differentiation by G34R/V mutations and malignant gliogenesis is promoted by co-option of a potentially targetable pathway, PDGFRA signaling.

• Klíčová slova
• GSX2, H3.3 G34R/V, PDGFRA, cell-of-origin, chromatin conformation, gliomas, interneuron progenitors, oncohistones, pediatric cancer, single-cell transcriptome,
• MeSH
• astrocyty metabolismus   patologie   MeSH
• biologické modely MeSH
• buněčný rodokmen MeSH
• chromatin metabolismus   MeSH
• embryo savčí metabolismus   MeSH
• epigeneze genetická MeSH
• genetická transkripce MeSH
• gliom genetika   patologie   MeSH
• histony genetika   metabolismus   MeSH
• interneurony metabolismus   MeSH
• karcinogeneze genetika   patologie   MeSH
• lysin metabolismus   MeSH
• mutace genetika   MeSH
• myši inbrední C57BL MeSH
• nádory mozku genetika   patologie   MeSH
• nervové kmenové buňky metabolismus   MeSH
• oligodendroglie metabolismus   MeSH
• přední mozek embryologie   MeSH
• přeprogramování buněk genetika   MeSH
• promotorové oblasti (genetika) genetika   MeSH
• regulace genové exprese u nádorů MeSH
• růstový faktor odvozený z trombocytů - receptor alfa genetika   metabolismus   MeSH
• stupeň nádoru MeSH
• transkriptom genetika   MeSH
• umlčování genů MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• chromatin MeSH
• histony MeSH
• lysin MeSH
• růstový faktor odvozený z trombocytů - receptor alfa MeSH