Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA304006 | ENA |
REPOSITORIES: ENA
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Project description:One critical task in pluripotent reprogramming is to erase the somatic transcriptional program of starting cells. No strategy or theory exists for achieving erasure of somatic gene expression memory. Here, we present a proof-of-principle strategy in which reprogramming to pluripotency is facilitated by small molecules that erase somatic cell transcription memory. We show that mild chemical targeting of the acetyllysine-binding pockets of the BET bromodomains, the transcriptional bookmarking domains, robustly enhances reprogramming. Furthermore, we show that chemical targeting of the transcriptional bookmarking BET bromodomains dramatically downregulates specific somatic gene expression programs in both naïve and reprogramming fibroblasts. Chemical blocking of the BET bromodomains also resulted in loss of fibroblast morphology early in reprograming. In this study, we experimentally demonstrate a concept for cell fate conversion: facilitating the conversion by chemically targeting the transcriptional bookmarking BET bromodomains responsible for transcriptional memory. human BJ cells were treated with JQ1 at 50 nM for 48 hours. Differential expression was compared with DMSO treatment. The same treatments and comparsion were conducted for reprogramming BJ cells, which were transduced with OCT4, SOX2, and KLF4. JQ1iPSC5 is a iPSC (induced pluripotent stem cell) line generated in this study using small molecules JQ1.
2016-08-22 | E-GEOD-75364 | biostudies-arrayexpress
Project description:One critical task in pluripotent reprogramming is to erase the somatic transcriptional program of starting cells. No strategy or theory exists for achieving erasure of somatic gene expression memory. Here, we present a proof-of-principle strategy in which reprogramming to pluripotency is facilitated by small molecules that erase somatic cell transcription memory. We show that mild chemical targeting of the acetyllysine-binding pockets of the BET bromodomains, the transcriptional bookmarking domains, robustly enhances reprogramming. Furthermore, we show that chemical targeting of the transcriptional bookmarking BET bromodomains dramatically downregulates specific somatic gene expression programs in both naïve and reprogramming fibroblasts. Chemical blocking of the BET bromodomains also resulted in loss of fibroblast morphology early in reprograming. In this study, we experimentally demonstrate a concept for cell fate conversion: facilitating the conversion by chemically targeting the transcriptional bookmarking BET bromodomains responsible for transcriptional memory.
2016-08-22 | GSE75364 | GEO
Project description:The MYC transcription factor is a master regulator of diverse cancer pathways and somatic cell reprogramming. MYC is a compelling therapeutic target that exhibits cancer-specific cellular effects. Pharmacologic inhibition of MYC function has proven challenging due to its numerous modes of forced expression and the difficulty of disrupting protein-DNA interactions. Here we demonstrate the rapid and potent abrogation of MYC gene transcription by representative small molecule bromodomain inhibitors of the BET family of chromatin adaptors. This transcriptional suppression of MYC was observed in the context of the natural, chromosomally translocated, and amplified gene locus. Inhibition of BET bromodomain-promoter interactions and subsequent reduction of MYC transcript and protein levels resulted in G1 arrest and extensive apoptosis in a variety of leukemia and lymphoma cell lines. Exogenous expression of MYC from an artificial promoter that is resistant to BET regulation significantly protected cells from growth suppression by BET inhibitors and revealed that MYC exerts a direct and tight control of key pro-growth and anti-apoptotic target genes. Transcriptional profiling of two cells after 4 and 8 hours of treatment with BET inhibitor shows that both MYC and its targets are strongly down-regulated. We thus demonstrate that pharmacologic inhibition of MYC is achievable through targeting BET bromodomains, and suggest that such inhibitors may have broad clinical applicability given the widespread pathogenetic role of MYC in cancer. LP-1, a multiple myeloma cell line, and Raji, a Burkitt lymphoma cell line, were treated with BET inhibitor and an inactive enantiomer for 4 or 8 hours. Two biological replicates of each sample were profiled on exon arrays.
2011-09-18 | E-GEOD-29449 | biostudies-arrayexpress
Project description:Bromodomains have emerged as attractive candidates for the development of inhibitors targeting gene transcription. Inhibitors of the bromo-and-extra-terminal (BET) family recently showed promising activity in diverse disease models. However, the pleiotropic nature of BET proteins regulating tissue specific transcription has raised safety concerns and suggested that attempts should be made for domain-specific targeting. Here we report that RVX-208, a compound currently in phase II clinical trials, is a BET bromodomain inhibitor specific for second bromodomains (BD2). Co-crystal structures revealed binding modes of RVX-208 and its synthetic precursor and fluorescent recovery after photobleaching demonstrated that RVX-208 displaces BET proteins from chromatin. However, gene expression data showed that BD2 inhibition only modestly affects BET-dependent gene transcription. Our data demonstrate the feasibility of specific targeting within the BET family resulting in different transcriptional outcomes and highlight the importance of BD1 in transcriptional regulation
2013-09-24 | GSE51143 | GEO
Project description:Pathologic activation of c-Myc plays a central role in pathogenesis of several neoplasias, including multiple myeloma. However, therapeutic targeting of c-Myc has remained elusive due to its lack of a clear ligand-binding domain. We therefore targeted c-Myc transcriptional function by another means, namely the disruption of chromatin-dependent signal transduction. Members of the bromodomain and extra-terminal (BET) subfamily of human bromodomain proteins (BRD2, BRD3 and BRD4) associate with acetylated chromatin and facilitate transcriptional activation by increasing the effective molarity of recruited transcriptional activators. Notably, BRD4 marks select M/G1 genes in mitotic chromatin for transcriptional memory and direct post-mitotic transcription, via direct interaction with the positive transcription elongation factor complex b (P-TEFb). Because c-Myc is known to regulate promoter-proximal pause release of Pol II, also through the recruitment of P-TEFb, we evaluated the selective small-molecule inhibitor of BET bromodomains, JQ1, as a chemical probe to interrogate the role of BET bromodomains in Myc-dependent transcription and to explore their role as therapeutic targets in c-Myc-driven neoplasias. Duplicate cultures of MM.1S, OPM1 and KMS11 human myeloma cells were treated with either DMSO alone or with JQ1 (500 nM), for 24 hours. Total RNA was extracted and hybridized to Affymetrix human Gene 1.0 ST microarrays (two arrays per treatment per cell line for a total of 12 arrays).
2011-09-01 | E-GEOD-31365 | biostudies-arrayexpress
Project description:Bromodomain inhibition comprises a promising therapeutic strategy in cancer, particularly for hematologic malignancies. To date, however, genomic biomarkers to direct clinical translation have been lacking. We conducted a cell-based screen of genetically-defined cancer cell lines using a prototypical inhibitor of BET bromodomains. Integration of genetic features with chemosensitivity data revealed a robust correlation between MYCN amplification and sensitivity to bromodomain inhibition. We characterized the mechanistic and translational significance of this finding in neuroblastoma, a childhood cancer with frequent amplification of MYCN. Genome-wide expression analysis demonstrated downregulation of the MYCN transcriptional program accompanied by suppression of MYCN transcription. Functionally, bromodomain-mediated inhibition of MYCN impaired growth and induced apoptosis in neuroblastoma. BRD4 knock-down phenocopied these effects, establishing BET bromodomains as transcriptional regulators of MYCN. BET inhibition conferred a significant survival advantage in three in vivo neuroblastoma models, providing a compelling rationale for developing BET bromodomain inhibitors in patients with neuroblastoma. Significance: Biomarkers of response to small-molecule inhibitors of BET bromodomains, a new compound class with promising anti-cancer activity, have been lacking. Here, we reveal MYCN amplification as a strong genetic predictor of sensitivity to BET bromodomain inhibitors, demonstrate a mechanistic rationale for this finding, and provide a translational framework for clinical trial development of BET bromodomain inhibitors for pediatric patients with MYCN-amplified neuroblastoma. JQ1 is a novel thieno-triazolo-1,4-diazepine, which displaces BET bromodomains from chromatin by competitively binding to the acetyl lysine recognition pocket. BE(2)-C and Kelly cells were treated in triplicate with 1 µM JQ1 or DMSO for 24 hours. RNA was extracted and a decrease in MYCN transcript was confirmed by real time RT-PCR as described above. The samples were profiled using the Affymetrix PrimeView Human Gene Expression Array (Affymetrix) at Beth Israel Deaconess Medical Center (Boston, MA, USA).
2013-02-25 | E-GEOD-43392 | biostudies-arrayexpress
Project description:Pathologic activation of c-Myc plays a central role in pathogenesis of several neoplasias, including multiple myeloma. However, therapeutic targeting of c-Myc has remained elusive due to its lack of a clear ligand-binding domain. We therefore targeted c-Myc transcriptional function by another means, namely the disruption of chromatin-dependent signal transduction. Members of the bromodomain and extra-terminal (BET) subfamily of human bromodomain proteins (BRD2, BRD3 and BRD4) associate with acetylated chromatin and facilitate transcriptional activation by increasing the effective molarity of recruited transcriptional activators. Notably, BRD4 marks select M/G1 genes in mitotic chromatin for transcriptional memory and direct post-mitotic transcription, via direct interaction with the positive transcription elongation factor complex b (P-TEFb). Because c-Myc is known to regulate promoter-proximal pause release of Pol II, also through the recruitment of P-TEFb, we evaluated the selective small-molecule inhibitor of BET bromodomains, JQ1, as a chemical probe to interrogate the role of BET bromodomains in Myc-dependent transcription and to explore their role as therapeutic targets in c-Myc-driven neoplasias.
2011-09-02 | GSE31365 | GEO
Project description:The MYC transcription factor is a master regulator of diverse cancer pathways and somatic cell reprogramming. MYC is a compelling therapeutic target that exhibits cancer-specific cellular effects. Pharmacologic inhibition of MYC function has proven challenging due to its numerous modes of forced expression and the difficulty of disrupting protein-DNA interactions. Here we demonstrate the rapid and potent abrogation of MYC gene transcription by representative small molecule bromodomain inhibitors of the BET family of chromatin adaptors. This transcriptional suppression of MYC was observed in the context of the natural, chromosomally translocated, and amplified gene locus. Inhibition of BET bromodomain-promoter interactions and subsequent reduction of MYC transcript and protein levels resulted in G1 arrest and extensive apoptosis in a variety of leukemia and lymphoma cell lines. Exogenous expression of MYC from an artificial promoter that is resistant to BET regulation significantly protected cells from growth suppression by BET inhibitors and revealed that MYC exerts a direct and tight control of key pro-growth and anti-apoptotic target genes. Transcriptional profiling of two cells after 4 and 8 hours of treatment with BET inhibitor shows that both MYC and its targets are strongly down-regulated. We thus demonstrate that pharmacologic inhibition of MYC is achievable through targeting BET bromodomains, and suggest that such inhibitors may have broad clinical applicability given the widespread pathogenetic role of MYC in cancer.
2011-09-19 | GSE29449 | GEO
Project description:Bromodomain inhibition comprises a promising therapeutic strategy in cancer, particularly for hematologic malignancies. To date, however, genomic biomarkers to direct clinical translation have been lacking. We conducted a cell-based screen of genetically-defined cancer cell lines using a prototypical inhibitor of BET bromodomains. Integration of genetic features with chemosensitivity data revealed a robust correlation between MYCN amplification and sensitivity to bromodomain inhibition. We characterized the mechanistic and translational significance of this finding in neuroblastoma, a childhood cancer with frequent amplification of MYCN. Genome-wide expression analysis demonstrated downregulation of the MYCN transcriptional program accompanied by suppression of MYCN transcription. Functionally, bromodomain-mediated inhibition of MYCN impaired growth and induced apoptosis in neuroblastoma. BRD4 knock-down phenocopied these effects, establishing BET bromodomains as transcriptional regulators of MYCN. BET inhibition conferred a significant survival advantage in three in vivo neuroblastoma models, providing a compelling rationale for developing BET bromodomain inhibitors in patients with neuroblastoma. Significance: Biomarkers of response to small-molecule inhibitors of BET bromodomains, a new compound class with promising anti-cancer activity, have been lacking. Here, we reveal MYCN amplification as a strong genetic predictor of sensitivity to BET bromodomain inhibitors, demonstrate a mechanistic rationale for this finding, and provide a translational framework for clinical trial development of BET bromodomain inhibitors for pediatric patients with MYCN-amplified neuroblastoma.
2013-02-25 | GSE43392 | GEO
Project description:Bromodomain and Extra-terminal motif (BET) proteins play a central role in transcription regulation and chromatin signalling pathways. In yeast, Bdf1 and its homologous protein Bdf2 are partially redundant and the deletion of both genes is lethal. Most of Bdf1 functions have been investigated in vegetative cells even if this protein is essential for sporulation. In this study, we explored for the first time the functional role of the Bdf1 bromodomains during the sporulation program. Extensive purification of Bdf1 partners identified two independent complexes with Bdf2 or the Swr1 complex. However, none of them are required for meiotic gene regulation or to complete sporulation. Taken together, our results unveil a new role for Bdf1 as a meiotic-specific gene transcriptional regulator independently of its predominant protein partners.
2017-01-11 | PXD005227 | Pride