Specific inhibition of p300-HAT alters Global Gene Expression and Repress HIV replication
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE7818 | GEO | 2007/05/18
SECONDARY ACCESSION(S): PRJNA100047
REPOSITORIES: GEO
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Project description:Reversible acetylation of histone and nonhistone proteins plays pivotal role in cellular homeostasis. Dysfunction of histone acetyltransferases (HATs) leads to several diseases including cancer, neurodegenaration, asthma, diabetes, AIDS and cardiac hypertrophy. We describe the synthesis and characterization of a set of p300-HAT specific small molecule inhibitors from a natural nonspecific HAT inhibitor, garcinol, which is highly toxic to cells. We show that the specific inhibitor selectively represses the p300-mediated acetylation of p53 in vivo. Furthermore, inhibition of p300-HAT down regulates several genes but significantly a few important genes are also upregulated. Remarkably, these inhibitors were found to be nontoxic to T cells, inhibit histone acetylation of HIV infected cells and consequently inhibit the multiplication of HIV. Keywords: Response to Inhibition of p300-HAT The total RNA was isolated from control and treated cells using TRIZOL (Invitrogen) method. The Micromax direct labeling kit, MPS502 (PerkinElmer) was used to synthesize the labeled cDNA from 70 ug of total RNA and further process the hybridized cDNA on the array. All the steps were carried out according to manufacturerâs instructions (www.perkinelmer.com/lifesciences). The array slides were scanned immediately by PerkinElmer Scan array Gx Microarray scanner. The Scan array software (PerkinElmer) was used for grid wise normalization of array images. Four arrays were used with at least two biological treatments of cells and dye swap experiments were included in the final analysis. The data was analysed by GeneSpring GX and Biointerpreter software from Genotypic Technology, Bangalore. The differential expression was considered if the Log 2 mean of at least -1 for the down regulated genes and +1 for the upregulated genes. We considered only the genes that were reproducible from all four replicates.
2010-06-11 | E-GEOD-7818 | biostudies-arrayexpress
Project description:Epigenetic events, including covalent post-translational modification of histones, have frequently been demonstrated to play critical roles in tumor development and progression. The transcriptional coactivator, p300/CBP, possesses both histone acetyltransferase (HAT) activity as well as scaffolding properties that directly influence transcriptional activation of targeted genes. We have used a recently reported small molecule inhibitor of p300 HAT activity, C646, to explore the specific contribution of p300/CBP HAT activity to tumor development and progression. We find that C646 inhibits the growth of lineage-specific tumor cell lines including human melanomas through direct transcriptional regulation of cell cycle regulatory proteins. Further evaluation of the p300 HAT transcriptome in human melanoma cells using comprehensive gene expression profiling reveals that p300 HAT activity globally promotes cell cycle progression, nucleosome assembly, and the DNA damage checkpoint through direct transcriptional regulatory mechanisms. Additionally, C646 promotes sensitivity to DNA damaging agents leading to enhanced apoptosis of melanoma cells following combination treatment with cisplatin. Together our data suggest that p300 HAT activity regulates critical growth regulatory pathways in tumors and may serve as a novel therapeutic target for melanoma and other malignancies by promoting cellular responses to DNA damaging agents. Keywords: p300, small molecule inhibitor, melanoma WM35 cells grown under normal culture conditions were treated for 6 and 24 hours with compound C646 to block p300 HAT activity. A vehicle control (DMSO) was included at each time point. RNA was extracted from all 4 samples using the Qiagen RNeasy kit. RNA quality check, labeling, hybridization, initial data processing and analysis was performed by the JHMI Microarray Core Facility. Affymetrix GeneChip Human Exon 1.0 ST Array was used for this study.
2013-08-01 | E-GEOD-45981 | biostudies-arrayexpress
Project description:Epigenetic events, including covalent post-translational modification of histones, have frequently been demonstrated to play critical roles in tumor development and progression. The transcriptional coactivator, p300/CBP, possesses both histone acetyltransferase (HAT) activity as well as scaffolding properties that directly influence transcriptional activation of targeted genes. We have used a recently reported small molecule inhibitor of p300 HAT activity, C646, to explore the specific contribution of p300/CBP HAT activity to tumor development and progression. We find that C646 inhibits the growth of lineage-specific tumor cell lines including human melanomas through direct transcriptional regulation of cell cycle regulatory proteins. Further evaluation of the p300 HAT transcriptome in human melanoma cells using comprehensive gene expression profiling reveals that p300 HAT activity globally promotes cell cycle progression, nucleosome assembly, and the DNA damage checkpoint through direct transcriptional regulatory mechanisms. Additionally, C646 promotes sensitivity to DNA damaging agents leading to enhanced apoptosis of melanoma cells following combination treatment with cisplatin. Together our data suggest that p300 HAT activity regulates critical growth regulatory pathways in tumors and may serve as a novel therapeutic target for melanoma and other malignancies by promoting cellular responses to DNA damaging agents. Keywords: p300, small molecule inhibitor, melanoma
2013-08-01 | GSE45981 | GEO
Project description:The transcriptional co-activator and acetyltransferase p300 is required for fundamental cellular processes, including differentiation and growth. Here, we report that p300 forms phase separated condensates in the cell nucleus. The phase separation ability of p300 is regulated by autoacetylation and relies on its catalytic core components, including the HAT domain, the autoinhibition loop, and bromodomain. p300 condensates sequester chromatin components, such as histone H3 tail and DNA, and are amplified through binding of p300 to the nucleosome. The catalytic HAT activity of p300 is decreased due to occlusion of the active site in the phase separated droplets, a large portion of which co-localizes with chromatin regions enriched in H3K27me3. Our findings suggest a model in which p300 condensates can act as a storage pool of the protein with reduced HAT activity, allowing p300 to be compartmentalized and concentrated at poised or repressed chromatin regions.
2021-08-26 | PXD026898 | Pride
Project description:The E1A binding protein P300 (EP300, also known as p300, lysine acetyltransferase 3B or KAT3B) and its close paralogue CREB-binding protein (CREBBP, aka CBP or KAT3A) possess intrinsic histone acetyltransferase (HAT) activity that can act on both histone and non-histone proteins. P300 and CBP are composed of multiple conserved protein domains, many of which are in proximity to the HAT domain modulating its catalytic activity. Here we show that the TAZ2 domain regulates the intrinsic catalytic activity of p300 in vitro and histone acetylation and chromatin accessibility in cells. Our study extends the knowledge of p300 self-regulation and provides new therapeutic stratagies for human cancers with corresponding p300/CBP mutations.
2023-08-07 | GSE193647 | GEO
Project description:The E1A binding protein P300 (EP300, also known as p300, lysine acetyltransferase 3B or KAT3B) and its close paralogue CREB-binding protein (CREBBP, aka CBP or KAT3A) possess intrinsic histone acetyltransferase (HAT) activity that can act on both histone and non-histone proteins. P300 and CBP are composed of multiple conserved protein domains, many of which are in proximity to the HAT domain modulating its catalytic activity. Here we show that the TAZ2 domain regulates the intrinsic catalytic activity of p300 in vitro and histone acetylation and chromatin accessibility in cells. Our study extends the knowledge of p300 self-regulation and provides new therapeutic stratagies for human cancers with corresponding p300/CBP mutations.
2023-08-07 | GSE193646 | GEO
Project description:The E1A binding protein P300 (EP300, also known as p300, lysine acetyltransferase 3B or KAT3B) and its close paralogue CREB-binding protein (CREBBP, aka CBP or KAT3A) possess intrinsic histone acetyltransferase (HAT) activity that can act on both histone and non-histone proteins. P300 and CBP are composed of multiple conserved protein domains, many of which are in proximity to the HAT domain modulating its catalytic activity. Here we show that the TAZ2 domain regulates the intrinsic catalytic activity of p300 in vitro and histone acetylation and chromatin accessibility in cells. Our study extends the knowledge of p300 self-regulation and provides new therapeutic stratagies for human cancers with corresponding p300/CBP mutations.
2023-08-07 | GSE193645 | GEO
Project description:The dynamic and reversible acetylation of proteins catalyzed by histone acetyltransferases (HATs) and histone deacetylases (HDACs) was discovered more than 2 decades ago and the enzymatic function of these enzymes are established as a major epigenetic regulatory mechanism of gene transcription. Thus, these epigenetic modifiers are involved in multiple diseases and represent attractive targets for therapeutic intervention. While HDAC inhibitors have been developed and approved by the FDA to treat certain cancers, progress on the development of drug-like HAT inhibitors has lagged. The HAT paralogs p300 and CBP (here called p300/CBP) are key transcriptional co-activators that are essential for a multitude of cellular processes and also implicated in human pathological conditions, including cancer. Current p300/CBP HAT domain inhibitors including natural products and bisubstrate analogs such as Lys-CoA either lack potency and selectivity or suffer from poor cellular permeability. C646 is widely utilized as a tool to inhibit p300/CBP HAT activity, but its off-target activity and reactivity may limit its cellular specificity. Here, we describe A-485 as a potent, selective and drug-like p300/CBP catalytic inhibitor. We show the first high resolution (1.95Å) co-crystal structure of a pharmacologically active small molecule (A-485) bound to the catalytic active site of p300 HAT domain and demonstrate that A-485 is an acetyl-CoA competitive inhibitor of p300/CBP. A-485 selectively inhibited proliferation across lineage-specific tumor types, including several hematological malignancies and androgen receptor-positive prostate cancer. A-485 robustly inhibited the androgen receptor transcriptional program in both androgen sensitive and castrate resistant prostate cancer and inhibited tumor growth in a castration resistant xenograft model. These results demonstrate the feasibility of selectively drugging the catalytic activity of histone acetyltransferases, provide the framework for delineating the enzymatic functions of HATs, and pave the way for the development of novel therapeutics targeting HAT activity.
2017-09-27 | GSE94580 | GEO
Project description:Human p300 is a transcriptional co-activator and a major acetyltransferase that acetylates histones and other proteins facilitating gene transcription. The activity of p300 relies on the fine-tuned interactome that involves a dozen p300 domains and hundreds of binding partners and links p300 to a wide range of vital signaling events. Here, we report on a novel function of the ZZ-type zinc finger (ZZ) of p300 as a reader of histone H3. We show that the ZZ domain and acetyllysine recognizing bromodomain (BD) of p300 play critical roles in modulating p300 enzymatic activity and its association with chromatin. Acetyllysine binding of BD is essential for acetylation of histones H3 and H4, whereas interaction of the ZZ domain with H3 promotes selective acetylation of histone H3K27 and H3K18.
2019-01-01 | GSE109591 | GEO
Project description:Coactivator CREB-binding protein (CBP) regulates the transcription program of p53, which orchestrates cellular responses to a wide-range of stress conditions that cause genomic instability. Given the ability of CBP to regulate transcription by multiple mechanisms, the biological significance of its acetylation-directed functions may not be fully clear. The present study demonstrates the development of a curcumin-derived modulator of CBP histone acetyl-transferase (HAT) activity, CM354, which inhibits acetylation of p53 on lysine 382, acetylation of histone H3K27 and autoacetylation of CBP. These epigenetic changes are concomitant with downregulation of p53 and CBP functions, which facilitate the presence of histone methyl transferase, Enhancer of zeste homolog 2 (EZH2), on CDKNI1A/p21 promoter, thereby, enhancing the level of trimethylation on H3K27. Treatment with CM354 results in the activation of PARP and the abrogation of cellular growth. Genome-wide network analysis depicts that CM354 could alter cell-fate by enrichment of chromatin H3K27 methylation and activation of the polycomb group of proteins. Though previously reported HAT inhibitors act at higher concentrations and lack cell permeability, the present study shows the impact of modulating endogenous CBP HAT activity on chromatin landscape and p53 functions.
2016-11-24 | GSE90460 | GEO