Anti-cancer drugs curaxins target the 3D genome organization [HiC]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE117582 | GEO | 2019/02/18
REPOSITORIES: GEO
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Project description:We have recently discovered a class of anti-cancer agents, curaxins, which suppress transcription of oncogenes. Here we demonstrate that curaxins preferentially downregulate expression of genes controlled by enhancers and super-enhancers via interrupting enhancer/promoter spatial communication. Our observations made both on a model of enhancer-regulated transcription of chromatinized template and on cultured cancer cells allow classifying curaxins as a novel type of epigenetic drugs that target the 3D genome organization.
2019-02-18 | GSE122462 | GEO
Project description:Much of mammalian physiology exhibits 24-hour cyclicity due to circadian rhythms of gene expression controlled by transcription factors (TF) that comprise molecular clocks. Core clock TFs bind to the genome at non-coding enhancer sequences to regulate circadian gene expression, but not all binding sites are equally functional. Here we demonstrate that circadian gene expression in mouse liver is controlled by rhythmic chromatin interactions between enhancers and promoters within topologically associating domains (TAD). Rev-erbα-, a core repressive TF of the clock, opposes functional loop formation between Rev-erbα-regulated enhancers and circadian target gene promoters by recruitment of the NCoR-HDAC3 corepressor complex, histone deacetylation, and eviction of the elongation factor BRD4 and the looping factor MED1. These loops are stronger and functionally active in the physiological or genetic absence of Rev-erbα.Thus, a repressive arm of the molecular clock operates by rhythmically interrupting enhancer-promoter loops to control circadian gene transcription.
2018-02-09 | GSE104129 | GEO
Project description:Recent epigenomic studies have predicted thousands of potential enhancers in the human genome. However, there has not been systematic characterization of target promoters for these potential enhancers. Using H3K4me2 as a mark for active enhancers, we identified genome-wide enhancer-promoter interactions in human CD4+ T cells. Among the 6,520 long-distance chromatin interactions, we identify 2,067 enhancers that interact with 1,619 promoters and enhance their expression. These enhancers exist in accessible chromatin regions and are associated with various histone modifications and Pol II binding. The promoters with interacting enhancers are expressed at higher levels than those without interacting enhancers and their expression levels are positively correlated with the number of interacting enhancers. Interestingly, interacting promoters are co-expressed in a tissue-specific manner. We also find that chromosomes are organized into multiple levels of interacting domains. Our results define a global view of enhancer-promoter interactions and provide a dataset to further understand mechanisms of enhancer targeting and long-range chromatin organization. Two biological replicates of ChIA-PET (Chromatin Interaction Analysis by Paired-End Tag Sequencing) experiment in CD4+ T cells
2012-01-24 | E-GEOD-32677 | biostudies-arrayexpress
Project description:Enhancers play key roles in gene regulation. However, comprehensive enhancer discovery is challenging because most enhancers, especially those affected in complex diseases, have weak effects on gene expression. Through gene regulatory network modeling, we identified that dynamic cell state transitions, a critical missing component in prevalent enhancer discovery strategies, can be utilized to improve the cells’ sensitivity to enhancer perturbation. Guided by the modeling results, we performed a mid-transition CRISPRi-based enhancer screen utilizing human embryonic stem cell definitive endoderm differentiation as a dynamic transition system. The screen discovered a comprehensive set of enhancers (4 to 9 per locus) for each of the core lineage-specifying transcription factors (TFs), including many enhancers with weak to moderate effects. Integrating the screening results with enhancer activity measurements (ATAC-seq, H3K27ac ChIP-seq) and three-dimensional enhancer-promoter interaction information (CTCF looping, Hi-C), we were able to develop a CTCF loop-constrained Interaction Activity (CIA) model that can better predict functional enhancers compared to models that rely on Hi-C-based enhancer-promoter contact frequency. Together, our dynamic network-guided enhancer screen and the CIA enhancer prediction model provide generalizable strategies for sensitive and more comprehensive enhancer discovery in both normal and pathological cell state transitions.
2023-06-17 | PXD043070 | Pride
Project description:Cell fate transitions are accompanied by global transcriptional, epigenetic and topological changes driven by transcription factors (TFs), as is strikingly exemplified by reprogramming somatic cells to pluripotent stem cells (PSCs) via expression of OCT4, KLF4, SOX2 and cMYC. How TFs orchestrate the complex molecular changes around their target gene loci in a temporal manner remains incompletely understood. Here, using KLF4 as a paradigm, we provide the first TF-centric view of chromatin reorganization and its association to 3D enhancer rewiring and transcriptional changes of linked genes during reprogramming of mouse embryonic fibroblasts (MEFs) to PSCs. Inducible depletion of KLF factors in PSCs caused a genome-wide decrease in the connectivity of enhancers, while disruption of individual KLF4 binding sites from PSC-specific enhancers was sufficient to impair enhancer-promoter contacts and reduce expression of associated genes. Our study provides an integrative view of the complex activities of a lineage-specifying TF during a controlled cell fate transition and offers novel insights into the order and nature of molecular events that follow TF binding.
2019-09-03 | PXD014631 | Pride
Project description:Metastases cause the majority of cancer-related deaths. Yet, the origins of metastatic cancer phenotypes remain poorly understood. Few metastasis-specific driver mutations have been identified [1-3], raising the possibility that metastatic transcriptional programmes may emerge from perturbations in the oncogenic signalling cascades that support the development of primary tumours. Here, using genome-wide histone modification profiling, high-throughput chromatin conformation capture by Hi-C and functional analysis in human-derived metastasis models of renal and breast cancers, we identify transcriptional enhancers that drive metastatic cancer progression. We demonstrate that specific enhancers and enhancer clusters are activated in metastatic cancer cell populations. The activation status of these enhancers is associated with gene expression patterns predictive of poor patient outcome in clinical samples. CRISPRi-mediated inhibition of enhancer activity and genetic ablation of enhancer sequences demonstrated the requirement of metastasis-associated regulatory elements for metastatic colonization in vivo. We further show that metastatic cancer clones co-opt evolutionarily conserved enhancers that converge on shared metastasis driver genes, such as CXCR4. Thus, we provide functional evidence for the requirement of specific enhancers for metastatic colonization and show that metastatic traits can arise through tissue-specific commissioning of distal gene regulatory elements.
2018-06-12 | GSE99051 | GEO
Project description:Fibroblasts transformed by the proto-oncogene Src form individual invadopodia that can spontaneously self-organize into large matrix-degrading superstructures called rosettes. However, the mechanisms by which the invadopodia can spatiotemporally reorganize their architecture is not well understood. Here, we show that Hic-5, a close relative of the scaffold protein paxillin, is essential for the formation and organization of rosettes in active Src-transfected NIH3T3 fibroblasts and cancer-associated fibroblasts. Live cell imaging, combined with domain-mapping analysis of Hic-5, identified critical motifs as well as phosphorylation sites that are required for the formation and dynamics of rosettes. Using pharmacological inhibition and mutant expression, we show that FAK kinase activity, along with its proximity to and potential interaction with the LD2,3 motifs of Hic-5, is necessary for rosette formation. Invadopodia dynamics and their coalescence into rosettes were also dependent on Rac1, formin, and myosin II activity. Superresolution microscopy revealed the presence of formin FHOD1 and INF2-mediated unbranched radial F-actin fibers emanating from invadopodia and rosettes, which may facilitate rosette formation. Collectively, our data highlight a novel role for Hic-5 in orchestrating the organization of invadopodia into higher-order rosettes, which may promote the localized matrix degradation necessary for tumor cell invasion.
| S-EPMC6724605 | biostudies-literature
Project description:Activation of the p53 tumor suppressor triggers a transcriptional program to control cellular response to stress. However, the molecular mechanisms by which p53 controls gene transcription are not completely understood. Here, using a multi-omics integration framework, we uncover the critical role of spatio-temporal genome architecture in this process. We demonstrate that p53 drives direct and indirect changes in genome compartments, topologically associating domains and DNA loops within minutes of its activation, which escort the p53 transcriptional program along time. Focused on p53-bound enhancers, we report a core transcriptional program of 340 genes directly regulated by p53 over distance, most of these not previously identified. Finally, we showcase that p53 controls transcription of distal genes through newly formed and pre-existing enhancer-promoter loops in a cohesin dependent manner. Taken together, our findings demonstrate a previously unappreciated architectural role of p53 as regulator at distinct topological layers and provide a reliable set of new p53 direct target genes that may help future designs of p53-based cancer therapies.
2024-04-17 | GSE235944 | GEO
Project description:Studying the dynamics of three-dimensional (3D) chromatin structure is essential to the understanding of biological processes in the nucleus. Integrative analysis of multi-omics data in recent publications have provided comprehensive and multilevel insight into 3D genome organization emphasizing its role for transcriptional regulation. While enhancers are regulatory elements that play a central role in the spatiotemporal control of gene expression, chromatin looping has been broadly accepted as a means for enhancer-promoter interactions yieldingcell-type-specific gene expression signatures. On the other hand, G-quadruplexes (G4s) are non-canonical DNA secondary structures that are enriched at promoters and related to increased gene expression, both. A role for G4s in promoter-distal regulatory elements, such as super-enhancers (SE), as well as in 3D genome organization and chromatin looping mediating long-range enhancer-promoter interactions has, however, remained elusive. Here we show that mature microRNA 9 (miR-9) is enriched at promoters and SE of genes that are inducible by tissue growth factor beta 1 (TGFB1) signaling. Further, we find that nuclear miR-9 is required for chromatin features related to increased transcriptional activity, such as broad domains of the euchromatin histone mark H3K4me3 (histone 3 tri-methylated lysine 4) and G4s. Moreover, we show that nuclear miR-9 is required for promoter-super-enhancer looping. Our study places a nuclear microRNA in the same structural and functional context with G4s and promoter-enhancer interactions during 3D genome organization and transcriptional activation induced by TGFB1 signaling, a critical regulator of proliferation programs in cancer and fibrosis.
2024-07-30 | MSV000095480 | MassIVE
Project description:Summary: Cell fate transitions are accompanied by global transcriptional, epigenetic and topological changes driven by transcription factors (TFs), as is strikingly exemplified in somatic cell reprogramming to pluripotent stem cells (PSCs) by OCT4, KLF4, SOX2 and cMYC. How TFs orchestrate the complex molecular changes around their targets in a temporal manner remains largely elusive. Here, using KLF4 as a paradigm, we provide the first TF-centric view of chromatin reorganization and the association to 3D enhancer rewiring and the transcriptional changes of linked genes during reprogramming of mouse embryonic fibroblasts to (MEFs) to PSCs. Inducible depletion of KLF factors in PSC caused a genome-wide decrease in connectivity of enhancers and disruption of KLF4 binding site from PSC-specific enhancers was sufficient to reduce expression of genes within the enhancer hub partly by impairing long-range contacts. Our study provides an integrative view of the intricate activities of a master regulator during a controlled cell fate transition and offers novel insights into the order and nature of molecular events that follow TF binding. Purpose: We captured on a genome-wide scale the binding of KLF4 during iPSC formation and its effects on chromatin state, transcriptional activity and chromatin topology around its targets. Methods: We used a well-characterized reprogramming system to apply genome-wide assays that map KLF4 binding (ChIP-seq), chromatin accessibility (ATAC-seq), enhancer and gene activity (H3K27ac ChIP-seq and RNA-seq), enhancer connectivity (H3K27ac Hi-ChIP) as well as KLF4-centric chromatin looping (KLF4 Hi-ChIP) at different stages during acquisition of pluripotency. Results: Integrative analysis of our results generated a reference map of stage-specific chromatin changes around KLF4 bound loci and established strong links with enhancer. rewiring and concordant transcriptional changes. Genetic manipulation of KLF4 binding from a PSC enhancer further supported the ability of KLF4 to function both as a transcriptional regulator and a chromatin organizer. Conclusions: Our study offers novel insights into the intricate roles of a master regulator during cell fate transition.
2019-09-06 | GSE113339 | GEO