Targeting p300/CBP axis in lethal prostate cancer
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE162564 | GEO | 2020/12/03
REPOSITORIES: GEO
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Project description:The acetyltransferases CBP and p300 are multifunctional transcriptional co-activators; however, their acetylation targets, site-specific acetylation kinetics, and function in proteome regulation are incompletely understood. We combined quantitative proteomics with novel CBP/p300-specific catalytic inhibitors, bromodomain inhibitor, and gene knockout to show that CBP/p300 acetylates thousands of sites, including signature histone sites, as well as a multitude of sites on signaling effectors and enhancer-associated transcriptional regulators. Kinetic analysis identified a subset of CBP/p300-regulated sites with very rapid (<30min) acetylation turnover, revealing a dynamic balance between acetylation and deacetylation. Quantification of acetylation, mRNA, and protein abundance after CBP/p300 inhibition reveals a kinetically competent network of gene expression that strictly depends on CBP/p300-catalyzed rapid acetylation. Collectively, our in-depth acetylome analyses reveal systems attributes of CBP/p300 targets, and the resource dataset provides a framework for investigating CBP/p300 functions, as well as for understanding the impact of small molecule inhibitors targeting its catalytic and bromodomain activities.
2018-06-10 | PXD005252 | Pride
Project description:Histone acetylation is important for the activation of gene transcription but little is known about its direct ‘read/write’ mechanisms. Here, we report cryo-electron microscopy structures in which a p300/CBP multidomain monomer recognizes histone H4 N-terminal tail (NT) acetylation (ac) in a nucleosome and acetylates non-H4 histone NTs within the same nucleosome. p300/CBP not only recognized H4NTac via the bromodomain pocket responsible for ‘reading’, but also interacted with the DNA minor grooves via the outside of that pocket. This directed the catalytic center of p300/CBP to one of the non-H4 histone NTs. The primary target that p300 ‘writes’ by ‘reading’ H4NTac was H2BNT, and H2BNTac promoted H2A-H2B dissociation from the nucleosome. We propose a model in which p300/CBP ‘replicates’ histone NT acetylation within the H3-H4 tetramer to inherit epigenetic storage, and ‘transcribes’ it from the H3-H4 tetramer to the H2B-H2A dimers to activate context-dependent gene transcription through local nucleosome destabilization.
2023-05-08 | PXD040835 | Pride
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:Targeting the p300/CBP axis in lethal prostate cancer.
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Project description:Activation of oncogenic gene expression from long-range enhancers is initiated by the assembly of DNA-binding transcription factors (TF), leading to recruitment of co-activators such as CBP/p300 to modify the local genomic context and facilitate RNA-Polymerase 2 (Pol2) binding. Yet, most TF-to-coactivator recruitment relationships remain unmapped. Here, studying the oncogenic fusion TF PAX3-FOXO1 (P3F) from alveolar rhabdomyosarcoma (aRMS), we show that a single cysteine in the activation domain (AD) of PAX3-FOXO1 forms a small alpha helical hook that recruits CBP/p300 to chromatin. P3F driven transcription requires both this single cysteine, and also CBP/p300. Furthermore, we discover a profound dependence on CBP/p300 for clustering of Pol2 loops that connect P3F to its target genes. In the absence of CBP/p300, Pol2 long range enhancer loops collapse, Pol2 accumulates in CpG islands and fails to exit the gene body. These results reveal a potential novel axis for therapeutic interference with P3F in aRMS and clarify the molecular relationship of P3F and CBP/p300 in sustaining active Pol2 clusters essential for oncogenic transcription.
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Project description:Dysregulated gene expression is one of the most prevalent features in human cancers. Here, we show that most subtypes of acute myeloid leukemia (AML) depend on the aberrant assembly of the MYB transcriptional co-activator complex. By rapid and selective peptidomimetic interference with the binding of CBP/P300 to MYB, but not CREB or MLL1, we find that the leukemic functions of MYB are mediated by CBP/P300-mediated co-activation of a distinct set of transcriptional factor complexes that are aberrantly assembled with MYB in AML cells. This therapeutic remodeling is accompanied by dynamic redistribution of CBP/P300 complexes to genes that control cellular differentiation and growth. Thus, aberrantly organized transcription factor complexes control convergent gene expression programs in AML cells. These findings establish a compelling strategy for pharmacologic reprogramming of oncogenic gene expression that supports its targeting for leukemias and other human cancers caused by dysregulated gene control.
2020-12-17 | PXD019708 | Pride
Project description:Reversible epsilon-amino acetylation of lysine residues regulates transcription as well as metabolic flux; however, roles for specific lysine acetyltransferases in skeletal muscle physiology and function remain enigmatic. In this study, we investigated the role of the homologous acetyltransferases p300 and CBP in skeletal muscle transcriptional homeostasis and physiology in adult mice. Mice with skeletal muscle-specific and inducible knockout of p300 and/or CBP were generated by crossing mice with a tamoxifen-inducible Cre recombinase expressed under the human alpha-skeletal actin (HSA) promoter with mice harboring LoxP sites flanking exon 9 of both the Ep300 and Crebbp genes. Knockout was induced at 13-15 weeks of age via oral gavage of tamoxifen. We demonstrate that loss of both p300 and CBP in adult mouse skeletal muscle severely impairs contractile function and results in lethality within one week – a phenotype that is reversed by the presence of a single allele of either p300 or CBP. The loss of muscle function in p300/CBP double knockout mice is paralleled by substantial transcriptional alterations in gene networks central to skeletal muscle contraction and structural integrity. Changes in protein expression patterns, determined by 10-plex TMT labeling, were linked to impaired muscle function also manifest within days (WT mice were compared to day 3 and day 5 knock out mice). Together, these data reveal the requirement of p300 and CBP for the control and maintenance of contractile function and transcriptional homeostasis in skeletal muscle, and ultimately, organism survival. By extension, modulating p300/CBP function holds promise for the treatment of disorders characterized by impaired contractile function in humans.
2020-04-03 | PXD015694 | Pride
Project description:We have performed RNA-seq on mouse islets lacking all p300 (p300 KO), all CBP (CBP-null), and one copy of CBP and all p300 (triallelic). The data revealed that p300 and CBP regulate some distinct but largely overlapping genes in islets. This was further confirmed by GO term and transcription factor target analyses, which suggested that these coactivators regulate genes that function similarly and converge to Hnf1a pathway.
2017-12-11 | GSE101537 | GEO