Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA137887 | ENA |
REPOSITORIES: ENA
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Project description:Epigenetic deregulation plays a critical role in the pathogenesis of Acute Myeloid Leukemia. But changes in histone modification patterns at the epigenome level still remain largely unknown. Here, we analyzed alterations of histone H3 acetylation patterns in a large number of patients with AML compared to CD34+ progenitor cells. Using ChIP-Chip assays, we demonstrate that AML blasts exhibit significant changes in Histone H3 acetylation levels at more than 1000 genomic loci. Importantly, at core promoter regions losses of H3 acetlyation levels prevailed which suggested that a large number of genes is epigenetically silenced in AML. The validation of identified genes led to the discovery of Peroxiredoxin 2 (PRDX2) as a potential tumor suppressor gene in AML. Peroxiredoxin-2 (PRDX2) was silenced in most AML patients by decreased Histone H3 acetylation and in almost 20% by promoter DNA hypermethylation. Low protein expression of the antioxidant PRDX2 gene was clinically associated with a poor prognosis in AML patients. Functionally, PRDX2 acted as an inhibitor of myeloid cell growth by reducing levels of reactive oxygen species generated in response to cytokines. A high level of PRDX2 expression inhibited myc-induced murine leukemogenesis whereas loss of PRDX2 increased myeloid cell proliferation and accelerated myc-induced leukemogenesis. Taken together, we identify widespread loss of Histone H3 acetylation at core promoter regions as a signature of AML blasts. Epigenome wide analyses of histone H3 acetylation led to the identification of PRDX2 as an epigenetically silenced growth suppressor that contributed to the malignant phenotype in AML. Blasts from patients with AML (n=72) were obtained at the time of diagnosis (in a few cases at first relapse). CD34+ progenitor cells (n=17) and white blood cells (n=16) were used as control samples. Immunoprecipitations were performed for anti-acetylated Histone H3. Chromatin-IPs were amplified using ligation mediated PCR and labeled using Cy3 coupled to incorporated amino-allyl-UTP. Common reference DNA consisting of a mixture of genomic DNA from AML patients was prepared, amplified and labeled in a similar way with Cy5.
2011-12-16 | E-GEOD-27863 | biostudies-arrayexpress
Project description:Epigenetic deregulation plays a critical role in the pathogenesis of Acute Myeloid Leukemia. But changes in histone modification patterns at the epigenome level still remain largely unknown. Here, we analyzed alterations of histone H3 acetylation patterns in a large number of patients with AML compared to CD34+ progenitor cells. Using ChIP-Chip assays, we demonstrate that AML blasts exhibit significant changes in Histone H3 acetylation levels at more than 1000 genomic loci. Importantly, at core promoter regions losses of H3 acetlyation levels prevailed which suggested that a large number of genes is epigenetically silenced in AML. The validation of identified genes led to the discovery of Peroxiredoxin 2 (PRDX2) as a potential tumor suppressor gene in AML. Peroxiredoxin-2 (PRDX2) was silenced in most AML patients by decreased Histone H3 acetylation and in almost 20% by promoter DNA hypermethylation. Low protein expression of the antioxidant PRDX2 gene was clinically associated with a poor prognosis in AML patients. Functionally, PRDX2 acted as an inhibitor of myeloid cell growth by reducing levels of reactive oxygen species generated in response to cytokines. A high level of PRDX2 expression inhibited myc-induced murine leukemogenesis whereas loss of PRDX2 increased myeloid cell proliferation and accelerated myc-induced leukemogenesis. Taken together, we identify widespread loss of Histone H3 acetylation at core promoter regions as a signature of AML blasts. Epigenome wide analyses of histone H3 acetylation led to the identification of PRDX2 as an epigenetically silenced growth suppressor that contributed to the malignant phenotype in AML.
2011-12-16 | GSE27863 | GEO
Project description:Aberrations in chromatin dynamics play a fundamental role in tumorigenesis, yet relatively little is known of the molecular mechanisms linking histone lysine methylation to neoplastic disease. ING4 (Inhibitor of Growth 4) is a native subunit of an HBO1 histone acetyltransferase (HAT) complex and a tumor suppressor protein. Here we show a critical role for the specific read-out of histone H3 trimethylated at lysine 4 (H3K4me3) by the ING4 PHD finger in mediating ING4 gene expression and tumor suppressor functions. The interaction between ING4 and H3K4me3 augments the acetylation activity of HBO1 on H3 tails, and drives H3 acetylation at ING4 target promoters to effect a DNA damage-dependent gene expression program. Further, ING4 facilitates apoptosis in response to genotoxic stress and inhibits anchorage-independent cell growth, and these functions are dependent on ING4 interactions with H3K4me3. Together, our results demonstrate a mechanism for brokering crosstalk between H3K4 methylation and histone H3 acetylation, and reveal a new molecular link between chromatin modulation and tumor suppressor mechanisms. ING4 ChIP-chip +/- Doxorubicin treatment in HT1080 cells on Nimblegen whole genome promoter array 4 samples: HT1080 cell lines stably expressing Flag-ING4 or Flag-ING4-D213A, +/- doxorubicin
2010-05-17 | E-GEOD-13412 | biostudies-arrayexpress
Project description:Aberrations in chromatin dynamics play a fundamental role in tumorigenesis, yet relatively little is known of the molecular mechanisms linking histone lysine methylation to neoplastic disease. ING4 (Inhibitor of Growth 4) is a native subunit of an HBO1 histone acetyltransferase (HAT) complex and a tumor suppressor protein. Here we show a critical role for the specific read-out of histone H3 trimethylated at lysine 4 (H3K4me3) by the ING4 PHD finger in mediating ING4 gene expression and tumor suppressor functions. The interaction between ING4 and H3K4me3 augments the acetylation activity of HBO1 on H3 tails, and drives H3 acetylation at ING4 target promoters to effect a DNA damage-dependent gene expression program. Further, ING4 facilitates apoptosis in response to genotoxic stress and inhibits anchorage-independent cell growth, and these functions are dependent on ING4 interactions with H3K4me3. Together, our results demonstrate a mechanism for brokering crosstalk between H3K4 methylation and histone H3 acetylation, and reveal a new molecular link between chromatin modulation and tumor suppressor mechanisms.
2008-11-05 | GSE13412 | GEO
Project description:MIR139 is a tumor suppressor and commonly silenced in Acute myeloid leukemia (AML). Reactivating the expression of MIR139 eliminates AML cells. Here, we investigated the mechanism of MIR139 gene inactivation in AML expressing the Mixed-Lineage Leukemia (MLL)-AF9 oncogene. We found that MLL-AF9-mediated repression of MIR139 is a selective event in leukemogenesis. Analyses of Histone marks revealed two well-conserved enhancer regions, which are epigenetically silenced by the Polycomb-Repressive Complex-2 (PRC2) downstream of MLL-AF9. Genomic deletion of these enhancer regions abolished transcriptional regulation of MIR139. Genome-wide knockout screens revealed the transcriptional pausing factor of RNA Polymerase-II, POLR2M, as a critical MIR139 silencing factor. Furthermore, POLR2M-binding to the MIR139 transcriptional start site induces paused transcription, which is abrogated upon PRC2 inhibition. Together, we present evidence for a POLR2M-mediated MIR139 silencing mechanism, downstream of MLL-AF9 and PRC2. The findings in this study highlight the importance of the transcriptional deregulation in malignant transformation.
2021-11-01 | GSE160405 | GEO
Project description:MIR139 is a tumor suppressor and commonly silenced in Acute myeloid leukemia (AML). Reactivating the expression of MIR139 eliminates AML cells. Here, we investigated the mechanism of MIR139 gene inactivation in AML expressing the Mixed-Lineage Leukemia (MLL)-AF9 oncogene. We found that MLL-AF9-mediated repression of MIR139 is a selective event in leukemogenesis. Analyses of Histone marks revealed two well-conserved enhancer regions, which are epigenetically silenced by the Polycomb-Repressive Complex-2 (PRC2) downstream of MLL-AF9. Genomic deletion of these enhancer regions abolished transcriptional regulation of MIR139. Genome-wide knockout screens revealed the transcriptional pausing factor of RNA Polymerase-II, POLR2M, as a critical MIR139 silencing factor. Furthermore, POLR2M-binding to the MIR139 transcriptional start site induces paused transcription, which is abrogated upon PRC2 inhibition. Together, we present evidence for a POLR2M-mediated MIR139 silencing mechanism, downstream of MLL-AF9 and PRC2. The findings in this study highlight the importance of the transcriptional deregulation in malignant transformation.
2021-11-01 | GSE160404 | GEO
Project description:MIR139 is a tumor suppressor and commonly silenced in Acute myeloid leukemia (AML). Reactivating the expression of MIR139 eliminates AML cells. Here, we investigated the mechanism of MIR139 gene inactivation in AML expressing the Mixed-Lineage Leukemia (MLL)-AF9 oncogene. We found that MLL-AF9-mediated repression of MIR139 is a selective event in leukemogenesis. Analyses of Histone marks revealed two well-conserved enhancer regions, which are epigenetically silenced by the Polycomb-Repressive Complex-2 (PRC2) downstream of MLL-AF9. Genomic deletion of these enhancer regions abolished transcriptional regulation of MIR139. Genome-wide knockout screens revealed the transcriptional pausing factor of RNA Polymerase-II, POLR2M, as a critical MIR139 silencing factor. Furthermore, POLR2M-binding to the MIR139 transcriptional start site induces paused transcription, which is abrogated upon PRC2 inhibition. Together, we present evidence for a POLR2M-mediated MIR139 silencing mechanism, downstream of MLL-AF9 and PRC2. The findings in this study highlight the importance of the transcriptional deregulation in malignant transformation.
2021-11-01 | GSE160403 | GEO
Project description:The FLT3-ITD mutation occurs in about 30% of acute myeloid leukemia (AML) and is associated with poor prognosis. However, FLT3 inhibitors are only partially effective and prone to acquired resistance. Here, we identified Yes-associated protein 1 (YAP1) as a tumor suppressor in FLT3-ITD+ AML. YAP1 inactivation conferred FLT3-ITD+ AML cells resistance to chemo- and targeted therapy. Mass spectrometric assay revealed DNA damage repair gene poly (ADP-ribose) polymerase 1 (PARP1) might be the downstream of YAP1, and the pro-proliferative effect by YAP1 knockdown were partly reversed via PARP1 inhibitor. Importantly, histone deacetylase 10 (HDAC10) contributed to decreased YAP1 acetylation levels through histone H3 lysine 27 (H3K27) acetylation, leading to the reduced nuclear accumulation of YAP1. Selective HDAC10 inhibitor chidamide or HDAC10 knockdown activated YAP1, enhanced DNA damage and significantly attenuated FLT3-ITD+ AML cells resistance. Additionally, combination chidamide with FLT3 inhibitors or chemotherapy agents synergistically inhibited growth and increased apoptosis of FLT3-ITD+AML cell lines and acquired resistant cells from the relapse FLT3-ITD+ AML patients. These findings demonstrate that the HDAC10-YAP1-PARP1 axis maintains FLT3-ITD+ AML cells and targeting this axis might improve clinical outcomes in FLT3-ITD+ AML patients._x001F__x001F__x001F__x001F_
2022-02-09 | GSE196258 | GEO
Project description:To uncover novel epigenetic regulators in AML, we performed an in vivo short hairpin RNA (shRNA) screen in the context of Cebpa mutant AML. This led to the identification of the Histone 3 Lysine 4 (H3K4) demethylase, KDM5C, as a novel tumor suppressor in AML. KDM5C potentially functions as a transcriptional repressor via its demethylase activity at promoters, and dysregulation could therefore have widespread consequences. Here, we found that reduced Kdm5c/KDM5C expression is associated with accelerated growth in both human and murine AML cell lines. In vivo, Kdm5c knockdown in a Cebpa mutant AML mouse model resulted in a more aggressive, immature and short-latency phenotype. Mechanistically, we show that knockdown of Kdm5c increased H3K4me3 globally. This translated into the up-regulation of a group of bivalently marked immature genes, resulting in a de-differentiation phenotype which could be reversed by modulating levels of pro-differentiation factors. Finally, we demonstrated that low levels of KDM5C were associated with a decrease in long-term disease-free survival, specifically in female patients. This emphasizes the clinical relevance of our findings and identifies KDM5C as a novel female-biased tumor suppressor in AML.
2023-03-10 | PXD016568 | Pride
Project description:Histone H3 globular domain acetylation identifies new class of enhancers
| PRJNA275703 | ENA