Pervasive H3K27 acetylation and ERV expression in H3.3K27M gliomas present a therapeutic vulnerability
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PROVIDER: EGAS00001003572 | EGA |
REPOSITORIES: EGA
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Project description:Epigenetic alterations are recurrently observed in cancer and are the subject of active therapeutic investigations. Midline high-grade gliomas (HGGs) are deadly brain tumors characterized by lysine-to-methionine substitutions at position 27 in histone 3 (H3) variants (denoted H3K27M), which are core components of the nucleosome. H3K27M, the first event in midline HGG development, results in a drastic loss of the repressive histone mark H3K27 tri-methylation (H3K27me3), and a notable increase in H3K27 acetylation (H3K27ac), a mark associated with active chromatin and cellular identity. H3K27ac gain was suggested to promote tumorigenesis in H3K27M-HGGs, but how these opposing marks shape oncogenesis remains controversial. We therefore characterized the active regulatory chromatin states in H3.3K27M and H3K27 wild-type HGGs and in H3.3K27M CRISPR/Cas9 knockout tumor-derived cell lines, as an isogenic tumor model of the mutation. We show that H3.3K27M-HGGs have distinct promoter, enhancer, super-enhancer, and core transcription factor circuitries from wild-type HGGs. However, while removal of H3.3K27M restores gross H3K27ac levels to those of wild-type HGGs, we observe minimal disruption of H3K27ac deposition at these active transcriptional elements, suggesting that they are a function of the cell of origin and independent of direct H3K27M mutagenesis and active regulation. Using quantitative ChIP-seq, we show that in H3.3K27M-HGGs, H3K27ac is pervasively deposited across the genome, including at normally silent repeat elements, leading to their increased baseline expression. H3.3K27M cells respond to DNA demethylating agents and histone deacetylase inhibitors, which further increase repeat element expression, including that of specific endogenous retroviral (ERVs) families. Our findings decouple cell lineage programs from H3K27M-dependent pervasive deposition of H3K27 acetylation. De-repression of ERVs may enhance the triggering of innate immune pathways, representing a therapeutic vulnerability in H3.3K27M HGGs.
2019-05-13 | GSE117446 | GEO
Project description:Epigenetic alterations are recurrently observed in cancer and are the subject of active therapeutic investigations. Midline high-grade gliomas (HGGs) are deadly brain tumors characterized by lysine-to-methionine substitutions at position 27 in histone 3 (H3) variants (denoted H3K27M), which are core components of the nucleosome. H3K27M, the first event in midline HGG development, results in a drastic loss of the repressive histone mark H3K27 tri-methylation (H3K27me3), and a notable increase in H3K27 acetylation (H3K27ac), a mark associated with active chromatin and cellular identity. H3K27ac gain was suggested to promote tumorigenesis in H3K27M-HGGs, but how these opposing marks shape oncogenesis remains controversial. We therefore characterized the active regulatory chromatin states in H3.3K27M and H3K27 wild-type HGGs and in H3.3K27M CRISPR/Cas9 knockout tumor-derived cell lines, as an isogenic tumor model of the mutation. We show that H3.3K27M-HGGs have distinct promoter, enhancer, super-enhancer, and core transcription factor circuitries from wild-type HGGs. However, while removal of H3.3K27M restores gross H3K27ac levels to those of wild-type HGGs, we observe minimal disruption of H3K27ac deposition at these active transcriptional elements, suggesting that they are a function of the cell of origin and independent of direct H3K27M mutagenesis and active regulation. Using quantitative ChIP-seq, we show that in H3.3K27M-HGGs, H3K27ac is pervasively deposited across the genome, including at normally silent repeat elements, leading to their increased baseline expression. H3.3K27M cells respond to DNA demethylating agents and histone deacetylase inhibitors, which further increase repeat element expression, including that of specific endogenous retroviral (ERVs) families. Our findings decouple cell lineage programs from H3K27M-dependent pervasive deposition of H3K27 acetylation. De-repression of ERVs may enhance the triggering of innate immune pathways, representing a therapeutic vulnerability in H3.3K27M HGGs.
2019-05-13 | GSE129135 | GEO
Project description:Epigenetic alterations are recurrently observed in cancer and are the subject of active therapeutic investigations. Midline high-grade gliomas (HGGs) are deadly brain tumors characterized by lysine-to-methionine substitutions at position 27 in histone 3 (H3) variants (denoted H3K27M), which are core components of the nucleosome. H3K27M, the first event in midline HGG development, results in a drastic loss of the repressive histone mark H3K27 tri-methylation (H3K27me3), and a notable increase in H3K27 acetylation (H3K27ac), a mark associated with active chromatin and cellular identity. H3K27ac gain was suggested to promote tumorigenesis in H3K27M-HGGs, but how these opposing marks shape oncogenesis remains controversial. We therefore characterized the active regulatory chromatin states in H3.3K27M and H3K27 wild-type HGGs and in H3.3K27M CRISPR/Cas9 knockout tumor-derived cell lines, as an isogenic tumor model of the mutation. We show that H3.3K27M-HGGs have distinct promoter, enhancer, super-enhancer, and core transcription factor circuitries from wild-type HGGs. However, while removal of H3.3K27M restores gross H3K27ac levels to those of wild-type HGGs, we observe minimal disruption of H3K27ac deposition at these active transcriptional elements, suggesting that they are a function of the cell of origin and independent of direct H3K27M mutagenesis and active regulation. Using quantitative ChIP-seq, we show that in H3.3K27M-HGGs, H3K27ac is pervasively deposited across the genome, including at normally silent repeat elements, leading to their increased baseline expression. H3.3K27M cells respond to DNA demethylating agents and histone deacetylase inhibitors, which further increase repeat element expression, including that of specific endogenous retroviral (ERVs) families. Our findings decouple cell lineage programs from H3K27M-dependent pervasive deposition of H3K27 acetylation. De-repression of ERVs may enhance the triggering of innate immune pathways, representing a therapeutic vulnerability in H3.3K27M HGGs.
2019-05-13 | GSE128744 | GEO
Project description:Epigenetic alterations are recurrently observed in cancer and are the subject of active therapeutic investigations. Midline high-grade gliomas (HGGs) are deadly brain tumors characterized by lysine-to-methionine substitutions at position 27 in histone 3 (H3) variants (denoted H3K27M), which are core components of the nucleosome. H3K27M, the first event in midline HGG development, results in a drastic loss of the repressive histone mark H3K27 tri-methylation (H3K27me3), and a notable increase in H3K27 acetylation (H3K27ac), a mark associated with active chromatin and cellular identity. H3K27ac gain was suggested to promote tumorigenesis in H3K27M-HGGs, but how these opposing marks shape oncogenesis remains controversial. We therefore characterized the active regulatory chromatin states in H3.3K27M and H3K27 wild-type HGGs and in H3.3K27M CRISPR/Cas9 knockout tumor-derived cell lines, as an isogenic tumor model of the mutation. We show that H3.3K27M-HGGs have distinct promoter, enhancer, super-enhancer, and core transcription factor circuitries from wild-type HGGs. However, while removal of H3.3K27M restores gross H3K27ac levels to those of wild-type HGGs, we observe minimal disruption of H3K27ac deposition at these active transcriptional elements, suggesting that they are a function of the cell of origin and independent of direct H3K27M mutagenesis and active regulation. Using quantitative ChIP-seq, we show that in H3.3K27M-HGGs, H3K27ac is pervasively deposited across the genome, including at normally silent repeat elements, leading to their increased baseline expression. H3.3K27M cells respond to DNA demethylating agents and histone deacetylase inhibitors, which further increase repeat element expression, including that of specific endogenous retroviral (ERVs) families. Our findings decouple cell lineage programs from H3K27M-dependent pervasive deposition of H3K27 acetylation. De-repression of ERVs may enhance the triggering of innate immune pathways, representing a therapeutic vulnerability in H3.3K27M HGGs.
2019-05-13 | GSE129136 | GEO
Project description:Enhancer activation is a critical step for gene activation. Here we report a novel epigenetic crosstalk at enhancers between the UTX (H3K27 demethylase)-MLL4 (H3K4 methyltransferase) complex and the histone acetyltransferase p300. We demonstrate that UTX, in a demethylase activity-independent manner, facilitates conversion of naïve (unmarked) enhancers in embryonic stem cells to an active (H3K4me1+/H3K27ac+) state by recruiting and coupling the enzymatic functions of MLL4 and p300. Loss of UTX leads to attenuated enhancer activity, characterized by reduced levels of H3K4me1 and H3K27ac as well as impaired transcription. The UTX-MLL4 complex enhances p300-dependent H3K27 acetylation through UTX-dependent stimulation of p300 recruitment while MLL4-mediated H3K4 monomethylation, reciprocally, requires p300 function. Importantly, MLL4-generated H3K4me1 further enhances p300-dependent transcription. This work reveals a previously unrecognized cooperativity among enhancer-associated chromatin modulators, including a unique function for UTX, in establishing an “active enhancer landscape” and defines a mechanism for the joint deposition of H3K4me1 and H3K27ac.
2017-07-06 | GSE97702 | GEO
Project description:Enhancer activation is a critical step for gene activation. Here we report a novel epigenetic crosstalk at enhancers between the UTX (H3K27 demethylase)-MLL4 (H3K4 methyltransferase) complex and the histone acetyltransferase p300. We demonstrate that UTX, in a demethylase activity-independent manner, facilitates conversion of naïve (unmarked) enhancers in embryonic stem cells to an active (H3K4me1+/H3K27ac+) state by recruiting and coupling the enzymatic functions of MLL4 and p300. Loss of UTX leads to attenuated enhancer activity, characterized by reduced levels of H3K4me1 and H3K27ac as well as impaired transcription. The UTX-MLL4 complex enhances p300-dependent H3K27 acetylation through UTX-dependent stimulation of p300 recruitment while MLL4-mediated H3K4 monomethylation, reciprocally, requires p300 function. Importantly, MLL4-generated H3K4me1 further enhances p300-dependent transcription. This work reveals a previously unrecognized cooperativity among enhancer-associated chromatin modulators, including a unique function for UTX, in establishing an “active enhancer landscape” and defines a mechanism for the joint deposition of H3K4me1 and H3K27ac.
2017-07-06 | GSE97701 | GEO
Project description:We analyzed the active H3K27 acetylation (H3K27ac) histone marker in hiPSC-Heps and hiHeps.The genome-wide H3K27ac occupancy analysis exhibited different patterns among these 4 types of cells. In accordance with the RNA-seq clustering results, the H3K27ac modifications of genes in seven clusters matched well with the active gene expressions in different cell types.
2017-11-23 | GSE103077 | GEO
Project description:Epigenetics, especially histone marks, functions beyond the DNA sequences to regulate gene expression. Depletion of NSD1, which catalyzes H3K36me2, led to both up- and down-regulation of gene expression, indicating NSD1 is associated with both active and repressed gene expression. It’s known that NSD1 regulates the deposition and expansion of H3K27me3, a repressive mark for gene expression, to keep active gene transcription. However, how NSD1 functions to repress gene expression is largely unknown. Here, we found that, when NSD1 was knocked out in mouse embryonic stem cells (mESCs), H3K27ac increased correlatively with the decrease of H3K36me2 at active enhancers, which is associated with mesoderm differentiation genes, leading to elevated gene expression. Mechanistically, NSD1 recruits HDAC1, the deacetylase of H3K27ac, to chromatin. Moreover, HDAC1 knockout (KO) recapitulates the increase of H3K27ac at active enhancers as the NSD1 depletion. Together, we propose that NSD1 deposits H3K36me2 and recruits HDAC1 at active enhancers to serve as a ‘safeguard’, preventing further activation of active enhancer-associated genes.
2021-06-15 | GSE169049 | GEO
Project description:Primed enhancers are marked by histone H3K4 mono-methylation (H3K4me1), and the conversion to active enhancers involves acetylation of histone H3K27 (H3K27Ac). However, whether active enhancers are regulated remains unclear. Here we report a biochemical complex consisting of a potential chromatin reader (RACK7) and a histone demethylase (KDM5C) that occupies many active enhancers in a breast cancer cell line. Loss of RACK7 or KDM5C results in hyperactive enhancers marked by H3K4me3 and H3K27Ac, and characterized by an increased eRNA transcription and elevated expression of nearby genes. Loss of RACK7 or KDM5C also leads to increased cell invasion and migration, and enhanced tumor growth. We propose that RACK7/KDM5C functions as an enhancer âbrakeâ to ensure appropriate enhancer activities in the cell. Our findings provide important insight into histone H3K4 methylation dynamics at enhancers and reveal a molecular mechanism that controls the activities of active enhancers, which when compromised, can contribute to tumorigenesis. mRNA-seq of parental and RACK7-KO ZR-75-30 cells
2016-04-07 | E-GEOD-71325 | biostudies-arrayexpress
Project description:Primed enhancers are marked by histone H3K4 mono-methylation (H3K4me1), and the conversion to active enhancers involves acetylation of histone H3K27 (H3K27Ac). However, whether active enhancers are regulated remains unclear. Here we report a biochemical complex consisting of a potential chromatin reader (RACK7) and a histone demethylase (KDM5C) that occupies many active enhancers in a breast cancer cell line. Loss of RACK7 or KDM5C results in hyperactive enhancers marked by H3K4me3 and H3K27Ac, and characterized by an increased eRNA transcription and elevated expression of nearby genes. Loss of RACK7 or KDM5C also leads to increased cell invasion and migration, and enhanced tumor growth. We propose that RACK7/KDM5C functions as an enhancer âbrakeâ to ensure appropriate enhancer activities in the cell. Our findings provide important insight into histone H3K4 methylation dynamics at enhancers and reveal a molecular mechanism that controls the activities of active enhancers, which when compromised, can contribute to tumorigenesis. nascent RNA-seq of parental and RACK7-KO cells
2016-04-07 | E-GEOD-71326 | biostudies-arrayexpress