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Updated: Jun 4, 2025
A Protocol for Explant Cultures of IDH1-mutant Diffuse Low-grade Gliomas
Published on: May 9, 2025
Multi-omics approaches reveal that diffuse midline gliomas present altered DNA replication and are susceptible to
Anastasia E Hains1, Kashish Chetal2,3, Tsunetoshi Nakatani4
1Department of Pathology, Stanford University, Stanford, CA, 94305, USA.
Background:
The fatal diffuse midline gliomas (DMG) are characterized by an undruggable H3K27M mutation in H3.1 or H3.3. K27M impairs normal development by stalling differentiation. The identification of targetable pathways remains very poorly explored. Toward this goal, we undertake a multi-omics approach to evaluate replication timing profiles, transcriptomics, and cell cycle features in DMG cells from both H3.1K27M and H3.3K27M subgroups and perform a comparative, integrative data analysis with healthy brain tissue.
Results:
DMG cells present differential replication timing in each subgroup, which, in turn, correlates with significant differential gene expression. Differentially expressed genes in S phase are involved in various pathways related to DNA replication. We detect increased expression of DNA replication genes earlier in the cell cycle in DMG cell lines compared to normal brain cells. Furthermore, the distance between origins of replication in DMG cells is smaller than in normal brain cells and their fork speed is slower, a read-out of replication stress. Consistent with these findings, DMG tumors present high replication stress signatures in comparison to normal brain cells. Finally, DMG cells are specifically sensitive to replication stress therapy.
Conclusions:
This whole genome multi-omics approach provides insights into the cell cycle regulation of DMG via the H3K27M mutations and establishes a pharmacologic vulnerability in DNA replication, which resolves a potentially novel therapeutic strategy for this non-curable disease.
Insights
Diffuse midline gliomas (DMG) with H3K27M mutations exhibit altered DNA replication, creating a vulnerability to replication stress therapies. This finding offers a potential new treatment strategy for this fatal brain cancer.
Area of Science:
- Genomics and Molecular Biology
- Cancer Research
- Cell Biology
Background:
- Diffuse midline gliomas (DMG) are fatal brain tumors characterized by the H3K27M mutation, which hinders normal brain development by disrupting cell differentiation.
- Targetable pathways for DMG remain largely unexplored, necessitating novel research approaches.
Purpose of the Study:
- To investigate the cell cycle regulation and identify targetable pathways in DMG by analyzing replication timing, transcriptomics, and cell cycle features.
- To compare multi-omics data from H3.1K27M and H3.3K27M DMG subgroups with healthy brain tissue.
Main Methods:
- A multi-omics approach was employed, integrating replication timing profiles, transcriptomics, and cell cycle analysis.
- Comparative analysis was performed between DMG cells (H3.1K27M and H3.3K27M) and normal brain tissue.
Main Results:
- DMG cells exhibit distinct replication timing patterns and differential gene expression, particularly in S phase genes related to DNA replication.
- DMG cells show earlier expression of DNA replication genes, reduced origin spacing, and slower replication fork speed, indicating replication stress.
- DMG tumors display significant replication stress signatures compared to normal brain cells.
Conclusions:
- The H3K27M mutation in DMG alters cell cycle regulation, leading to increased replication stress.
- DMG cells are specifically sensitive to therapies targeting replication stress, suggesting a novel therapeutic strategy for this incurable disease.
