ABSTRACT: Critical drivers of cancer progression are likely controlled through the actions of transcription factors and cofactors that bind to the genome and form enhancers that stimulate gene expression. We present ChIP-seq analysis of key transcriptional regulators, cofactors and histone modifications that indicate transcriptional activity across a range of different cancer cells. ChIP-seq was performed against the cofactors Med1, Brd4 and CDK7 in MM1.S multiple myeloma cells; Brd4 in Sk-MEL-5 melanoma cells; and H3K9/K14 acetylation in MV4;11 leukemia cells,
Project description:Discovery of the genome-wide location of proteins using ChIP-Seq has allowed global mapping of the key transcription factors and chromatin regulators that control gene expression programs in various cells. Many DNA-associated processes are targeted for disease therapy. This study investigates the functions of small molecule therapeutics that target DNA-associated processes involved of CDK9 and BRD4. Genomic DNA was enriched by chromatin immunoprecipitation (ChIP) and analyzed by Solexa sequencing. ChIP was performed using an antibody against RNAP2, BRD4, CDK9, and CTCF using whole cell extract (WCE) as a background control.
Project description:Chromatin regulators have become highly attractive targets for cancer therapy, yet many of these regulators are expressed in a broad range of healthy cells and contribute generally to gene expression. An important conundrum has thus emerged: how can inhibition of a general regulator of gene expression produce selective effects at specific oncogenes? Here we investigate how inhibition of the transcriptional coactivator BRD4 (Bromodomain containing 4) leads to selective inhibition of disease-critical oncogenes in a highly malignant blood cancer, multiple myeloma (MM). We found that BRD4 generally occupies the promoter elements of active genes together with the Mediator coactivator, but remarkably high levels of these two coactivator proteins were associated with a small set of exceptionally large enhancers. These super-enhancers are associated with genes that feature prominently in MM biology, including the MYC oncogene. Treatment of MM tumor cells with the BET-bromodomain inhibitor JQ1 led to preferential loss of BRD4 at super-enhancers and consequent transcription elongation defects that preferentially impact genes with super-enhancers, including the c-MYC oncogene. Super-enhancers were found at key oncogenic drivers in many other tumor cells. Thus, super-enhancers can regulate oncogenic drivers in tumor cells, which in some cells can be preferentially disrupted by BRD4 inhibition, which in turn contributes to the selective transcriptional effects observed at these oncogenes. These observations have implications for the discovery of novel cancer therapeutics directed at components of super-enhancers in diverse tumor types. ChIP-Seq for chromatin regulators and RNA Polymerase II in multiple myeloma, glioblastoma multiforme, and small cell lung cancer
Project description:An ability to map the global interactions of a chemical entity with chromatin genome-wide could provide new insights into the mechanisms by which a small molecule perturbs cellular functions. we developed a method that uses chemical derivatives and massively parallel DNA sequencing (Chem-Seq) to identify the sites bound by small chemical molecules throughout the human genome. We developed in vivo and in vitro Chem-Seq protocols with a biotinylated derivative of small molecules. In the in vivo protocol, Cells were first treated with biotinylated ligand and cross-linked with formaldehyde at the same time. Cells were then lysed, sonicated to shear the DNA, and streptavidin beads were used to isolate biotinylated ligand and associated chromatin fragments. We then used massively parallel sequencing to identify the enriched DNA fragments, and mapped these sequences to the genome. In in vitrol protocol, MM1.S cells were fixed and the derived sonicated lysate incubated with biotinylated drug to enrich for bound chromatin regions in vitro. We then used massively parallel sequencing to identify the enriched DNA fragments, and mapped these sequences to the genome.
Project description:MM1.S cells are an aggressive dexamethasone sensitive multiple myeloma cell line whose transcritional program is driven by deregulated c-Myc activity. We present ChIP-seq analysis of key transcritional regulators that are implicated the c-Myc transcriptional network in MM1.S cells treated with vehicle or 500nM JQ1. Brd4, Cdk9, cMyc, Max, Med1, RNA Pol II, and the chromatin modifications H3K4me3 and H3K27Ac were profiled in MM1.S cells treated with 500nM JQ1 for 24hr
Project description:Discovery of the genome-wide location of proteins using ChIP-Seq has allowed global mapping of the key transcription factors and chromatin regulators that control gene expression programs in various cells. Many DNA-associated processes are targeted for disease therapy. This study investigates the functions of small molecule therapeutics that target DNA-associated processes involved with CDK9 and BRD4. Genomic DNA was enriched by chromatin immunoprecipitation (ChIP) and analyzed by Solexa sequencing. ChIP was performed using an antibody against Brd4, RNA Polymerase II, Med1, H3K27ac, and CDK8 as well as whole-cell extract (WCE) DNA controls
Project description:P493-6 cells are immortalized human peripheral B cells that carry a conditional, tetracycline-regulated myc gene. We present ChIP-seq analysis of key transcritional regulators in P493-6 cells expressing various levels of c-Myc: 0hr (low c-Myc levels), 1hr (intermediate c-Myc levels), 24hr (very high c-Myc levels) and No Tet (steady-state c-Myc levels). Brd4, c-Myc, Max, Med1, RNAPII, and the chromatin modification H3K27Ac were profiled in P493-6 cells
Project description:Proinflammatory stimuli rapidly and globally remodel chromatin landscape, thereby enabling transcriptional responses. Yet, the mechanisms coupling chromatin regulators to the master regulatory inflammatory transcription factor NF-kB remain poorly understood. We report in human endothelial cells (ECs) that activated NF-kB binds to enhancers, provoking a rapid, global redistribution of BRD4 preferentially at super-enhancers, large enhancer domains highly bound by chromatin regulators. Newly established NF-kB super-enhancers drive nearby canonical inflammatory response genes. In both ECs and macrophages BET bromodomain inhibition prevents super-enhancer formation downstream of NF-kB activation, abrogating proinflammatory transcription. In TNFa-activated endothelium this culminates in functional suppression of leukocyte rolling, adhesion and transmigration. Sustained BET bromodomain inhibitor treatment of LDLr -/- animals suppresses atherogenesis, a disease process rooted in pathological vascular inflammation involving endothelium and macrophages. These data establish BET-bromodomains as key effectors of inflammatory response through their role in the dynamic, global reorganization of super-enhancers during NF-kB activation. ChIP-Seq for various transcription factors, RNA Polymerase II, and histone modifications in human endothelial cells
Project description:H3K27me3 is a chromatin modification depositied by Suz12, a component of the Polycomb Group 2 complex, and is associated with transcriptional repression. In contrast, H3K79me2 is a chromatin modification associated with active gene transcription. It is deposited by the histone methyltransferase Dot1L and generally is localized just downstream of the transcriptional start site and extends down the body of the gene. To gain insight into the transcriptional state of genes in hES cells, chromatin immunoprecipitation coupled with massive parallel sequencing (ChIP-seq) was performed to determine the genome-wide occupancy of the H3K27me3 and H3K79me2 chromatin modifications and genome-wide occupancy of the Suz12. DNA was enriched by chromatin immunoprecipitation (ChIP) and analyzed by Solexa sequencing A sample of whole cell extract was sequenced and used as the background to determine enrichment. ChIP was performed using an antibody against H3K27me3, H3K79me2, and Suz12 (Abcam).
Project description:Condensin molecules are loaded onto the genome to mediate essential changes in chromosome condensation during mitosis, but it is not clear why there are two forms of vertebrate condensin that become differentially distributed on chromosomes. We report here that condensin II, the form of condensin present in the nucleus throughout the cell cycle, functions specifically at active genes. Condensin II is loaded at transcriptionally active promoters in embryonic stem cells (ESCs), migrates through these genes in a transcription-dependent fashion and accumulates in transcription termination regions. Unlike cohesin, which is also loaded at active promoters, condensin II has little influence on transcription. We conclude that condensin II is loaded and distributed across actively transcribed chromatin and thus serves to specifically condense this euchromatic portion of chromosomes during the cell division cycle. ChIP-Seq data for Condensin II and Cohesin in v6.5 ESCs treated or not with the RNA polymerase II elongation inhibitor flavopiridol.
Project description:Multiple protein complexes and histone marks have been implicated and/or associated with gene repression in ES cells. To gain insights into repressive complexes present at repressed genes and their associated chromatin state, we profiled REST, MCAF1, Ring1b and H4K20me3 in mouse ES cells. DNA was enriched by chromatin immunoprecipitation (ChIP) and analyzed by Solexa sequencing. ChIP was performed using an antibody against REST, MCAF1, Ring1b and H4K20me3.