Senescence induced by BMI1 inhibition is a therapeutic vulnerability in H3K27M-mutant DIPG
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PROVIDER: PRJNA590880 | ENA |
REPOSITORIES: ENA
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Project description:We studied the effect of BMI1 inhibition in diffuse intrinsic pontine glioma cells (DIPG). We reported the application of chromatin immunoprecipitation sequencing for high-thoughput profiling of BMI1 and H2AK119ub in diffuse intrinsic pontine glioma cells (DIPG) in response to BMI1 inhibition. We also performed bulk RNA sequencing of DIPG cells in response to pharmacological inhibition or knockdown of BMI1.
2020-10-22 | GSE140768 | GEO
Project description:The lysine-to-methionine mutation at residue 27 of histone H3 (H3K27M) is a driving mutation in Diffuse Intrinsic Pontine Glioma (DIPG), a highly aggressive form of pediatric brain tumor with no effective treatment and little chance of survival. H3K27M reshapes the epigenome through a global inhibition of PRC2 catalytic activity, displacement of methylation at lysine 27 of histone H3 (H3K27me2/3), and thus promoting oncogenesis of DIPG. As a consequence, a histone modification H3K36me2, antagonistic to H3K27me2/3, is aberrantly elevated. Here, we investigate the role of H3K36me2 in H3K27M-DIPG by tackling its upstream catalyzing enzymes (writers) and downstream binding factors (readers). We determine that NSD1 and NSD2 are the key writers for H3K36me2. Loss of NSD1/2 in H3K27M-DIPG impedes cellular proliferation in vitro and tumorigenesis in vivo, and disrupts tumor-promoting gene expression programs. Further, we demonstrate that LEDGF and HDGF2 are the main readers that mediate the pro-tumorigenic effects downstream of NSD1/2-H3K36me2. Treatment with a chemically modified peptide mimicking endogenous H3K36me2 dislodges LEDGF/HDGF2 from chromatin and specifically inhibits the proliferation of H3K27M-DIPG. Together, our results indicate a functional pathway of NSD1/2-H3K36me2-LEDGF/HDGF2 as an acquired dependency in H3K27M-DIPG and suggest a possibility to target this pathway for therapeutic interventions.
2021-07-21 | GSE174006 | GEO
Project description:Diffuse intrinsic pontine glioma (DIPG) is an incurable brain tumor of childhood characterized by histone mutations at lysine 27, which results in epigenomic dysregulation. There has been a failure to develop effective treatment for this tumor. Using a combined RNAi and chemical screen targeting epigenomic regulators, we identify the polycomb repressive complex 1 (PRC1) component BMI1 as a critical factor for DIPG tumor maintenance in vivo. BMI1 chromatin occupancy is enriched at genes associated with differentiation and tumor suppressors in DIPG cells. Inhibition of BMI1 decreases cell self-renewal and attenuates tumor growth due to induction of senescence. Prolonged BMI1 inhibition induces a senescence-associated secretory phenotype, which promotes tumor recurrence. Clearance of senescent cells using BH3 protein mimetics co-operates with BMI1 inhibition to enhance tumor cell killing in vivo.
| S-EPMC7574900 | biostudies-literature
Project description:Diffuse intrinsic pontine gliomas (DIPG) are characterized by a heterozygous lysine-to-methionine mutation of histone H3 (H3K27M) that potently reduces Polycomb Repressive Complex 2 (PRC2) methylation of wild-type histone H3K27 (H3K27wt). The role of H3K27M and reduced H3K27wt methylation in DIPG pathogenesis has yet to be determined. Here, we have performed epigenomic profiling of patient-derived H3K27M mutant DIPG cells and demonstrate that H3K27M resides in nucleosomes with H3K27wt acetylation (H3K27ac), and H3K27M-H3K27ac containing nucleosomes co-localize with bromodomain proteins at actively transcribed genes and that PRC2 is excluded from H3K27M occupied regions. With respect to therapeutic implications of these observations, we demonstrate that pharmacologic bromodomain protein inhibition suppresses tumor growth in vivo. In total, our results indicate that H3K27M promotes H3K27ac at the expense of H3K27 methylation, and points to bromodomain protein inhibition as a clinical strategy for treating DIPG.
2017-02-27 | GSE78801 | GEO
Project description:The H3K36me2 writer-reader dependency in H3K27M-DIPG
| PRJNA727843 | ENA
Project description:Lysine 27 to methionine mutation (H3K27M) of the H3F3A gene, which encodes the variant histone H3.3, is found in the majority of Diffuse Intrinsic Pontine Gliomas (DIPGs). DIPGs are the most aggressive form of pediatric gliomas and have a median survival of <1 year from diagnosis. As H3K27M mutation is necessary but not sufficient to cause DIPGs, it is accompanied by several other mutations in tumors. However, the mechanisms by which H3K27M increases vulnerability to DIPG tumorigenesis, while expected to involve altered epigenetic regulation is unclear. Thus, in this work we built pairs of isogenic human embryonic stem cell lines with versus without this mutation, in the absence of other DIPG contributory mutations, to investigate mechanisms by which H3K27M mutation could affect cellular proliferation and differentiation and how these were related to alterations in the transcriptome, H3K27me3, and the DNA methylome. We found that H3K27M increased stem cell proliferation and interfered with differentiation, resulting in loss of most H3K27me3 and resulting in anomalous onset of expression of developmental genes during multilineage or directed differentiation. This work suggests mechanisms by which H3K27M mutation influences stem cell properties, contributing to DIPG tumorigenesis.
2021-12-31 | GSE158143 | GEO
Project description:Lysine 27 to methionine mutation (H3K27M) of the H3F3A gene, which encodes the variant histone H3.3, is found in the majority of Diffuse Intrinsic Pontine Gliomas (DIPGs). DIPGs are the most aggressive form of pediatric gliomas and have a median survival of <1 year from diagnosis. As H3K27M mutation is necessary but not sufficient to cause DIPGs, it is accompanied by several other mutations in tumors. However, the mechanisms by which H3K27M increases vulnerability to DIPG tumorigenesis, while expected to involve altered epigenetic regulation is unclear. Thus, in this work we built pairs of isogenic human embryonic stem cell lines with versus without this mutation, in the absence of other DIPG contributory mutations, to investigate mechanisms by which H3K27M mutation could affect cellular proliferation and differentiation and how these were related to alterations in the transcriptome, H3K27me3, and the DNA methylome. We found that H3K27M increased stem cell proliferation and interfered with differentiation, resulting in loss of most H3K27me3 and resulting in anomalous onset of expression of developmental genes during multilineage or directed differentiation. This work suggests mechanisms by which H3K27M mutation influences stem cell properties, contributing to DIPG tumorigenesis.
2021-12-31 | GSE159465 | GEO
Project description:Lysine 27 to methionine mutation (H3K27M) of the H3F3A gene, which encodes the variant histone H3.3, is found in the majority of Diffuse Intrinsic Pontine Gliomas (DIPGs). DIPGs are the most aggressive form of pediatric gliomas and have a median survival of <1 year from diagnosis. As H3K27M mutation is necessary but not sufficient to cause DIPGs, it is accompanied by several other mutations in tumors. However, the mechanisms by which H3K27M increases vulnerability to DIPG tumorigenesis, while expected to involve altered epigenetic regulation is unclear. Thus, in this work we built pairs of isogenic human embryonic stem cell lines with versus without this mutation, in the absence of other DIPG contributory mutations, to investigate mechanisms by which H3K27M mutation could affect cellular proliferation and differentiation and how these were related to alterations in the transcriptome, H3K27me3, and the DNA methylome. We found that H3K27M increased stem cell proliferation and interfered with differentiation, resulting in loss of most H3K27me3 and resulting in anomalous onset of expression of developmental genes during multilineage or directed differentiation. This work suggests mechanisms by which H3K27M mutation influences stem cell properties, contributing to DIPG tumorigenesis.
2021-12-31 | GSE159070 | GEO
Project description:Diffuse intrinsic pontine glioma (DIPG) is a rare pediatric brain tumor with a median survival of 10-15 months. Histone H3 is mutated in 80% of DIPGs, dictating tumor location, onset, and outcome. Therapeutic resistance remains a major obstacle to preventing tumor recurrence and is in part driven by cancer stem cells (CSCs), which exhibit self-renewal properties and tumorigenic potential. In previous studies, we have identified these proliferative and tumorigenic features in aldehyde dehydrogenase positive (ALDH+) CSCs in H3K27M mutant DIPG. We hypothesize that ALDH-mediated cancer stemness and resistance may in part be driven by H3K27M. ALDH1A3 expression was reduced in CRISPR-edited DIPG cells (SU-DIPG-XIII) where the H3K27M mutation had been removed (H3K27M-KO). Furthermore, these gained differentiation characteristics and lost their neurosphere-forming potential. The parental (H3K27M) and H3K27M-KO cells were also subjected to ionizing radiation to identify genes responsible for radioresistance in histone-mutated DIPG radioresistance. Nascent transcriptomes were obtained from these cells using bromouridine labeling and capture followed by sequencing (Bru-seq).
2023-08-30 | GSE211833 | GEO
Project description:Diffuse intrinsic pontine glioma (DIPG) is a fatal malignancy of the childhood pons characterized by a unique lysine-to-methionine substitution in histone-3 at lysine 27 (H3K27M). We show here that the specific Polycomb targets disrupted by H3K27M and resultant oncogenic state is dependent on both the variant of histone-3 and the cell- context in which the mutation occurs. Through primary DIPG tumor characterization and isogenic expression, we show that the same H3K27M mutation displays distinct modes of oncogenic reprogramming and establishes distinct enhancer architecture depending on whether it occurs in genes encoding H3.3 or H3.1. By comparison to non-malignant pediatric pontine tissue, we create a molecular map for DIPG, identifying and functionally validating both shared and subgroup-specific pathophysiology. Directly comparing the earliest events of H3K27M tumor initiation in putative cells-of-origin demonstrates that DIPG arises only from an oligodendrocyte precursor cell state.
2019-10-03 | GSE126319 | GEO