Super-enhancers (SEs), which are composed of large clusters of enhancers densely loaded with the Mediator complex, transcription factors and chromatin regulators, drive high expression of genes implicated in cell identity and disease, such as lineage-controlling transcription factors and oncogenes. BRD4 and CDK7 are positive regulators of SE-mediated transcription. By contrast, negative regulators of SE-associated genes have not been well described. Here we show that the Mediator-associated kinases cyclin-dependent kinase 8 (CDK8) and CDK19 restrain increased activation of key SE-associated genes in acute myeloid leukaemia (AML) cells. We report that the natural product cortistatin A (CA) selectively inhibits Mediator kinases, has anti-leukaemic activity in vitro and in vivo, and disproportionately induces upregulation of SE-associated genes in CA-sensitive AML cell lines but not in CA-insensitive cell lines. In AML cells, CA upregulated SE-associated genes with tumour suppressor and lineage-controlling functions, including the transcription factors CEBPA, IRF8, IRF1 and ETV6. The BRD4 inhibitor I-BET151 downregulated these SE-associated genes, yet also has anti-leukaemic activity. Individually increasing or decreasing the expression of these transcription factors suppressed AML cell growth, providing evidence that leukaemia cells are sensitive to the dosage of SE-associated genes. Our results demonstrate that Mediator kinases can negatively regulate SE-associated gene expression in specific cell types, and can be pharmacologically targeted as a therapeutic approach to AML.
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Specimen part, Cell line, Treatment
View SamplesWe characterized the marine natural product cortistatin A (CA) as an inhibitor of CDK8 to determine whether pharmacologic inhibition of CDK8 regulates super-enhancer function and inhibits AML proliferation.
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Specimen part, Cell line, Treatment
View SamplesWe characterized the marine natural product cortistatin A (CA) as an inhibitor of CDK8 to determine whether pharmacologic inhibition of CDK8 regulates super-enhancer function and inhibits AML proliferation.
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Specimen part, Cell line, Treatment
View SamplesWe characterized the marine natural product cortistatin A (CA) as an inhibitor of CDK8 to determine whether pharmacologic inhibition of CDK8 regulates super-enhancer function and inhibits AML proliferation.
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Specimen part, Cell line, Treatment
View SamplesWe characterized the marine natural product cortistatin A (CA) as an inhibitor of CDK8 to determine whether pharmacologic inhibition of CDK8 regulates super-enhancer function and inhibits AML proliferation.
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
Specimen part, Cell line, Treatment
View SamplesWe characterized the marine natural product cortistatin A (CA) as an inhibitor of CDK8 to determine whether pharmacologic inhibition of CDK8 regulates super-enhancer function and inhibits AML proliferation. In this series, we examine the transcriptional effect on insensitive HCT116 cells of 3hrs exposure to CA. Overall design: HCT116 cells were treated in triplicate with either DMSO or CA for 3hrs after which RNA was harvested and prepared for RNA sequencing to assess transcriptional changes.
Mediator kinase inhibition further activates super-enhancer-associated genes in AML.
No sample metadata fields
View SamplesIn order to define the transcriptional network functionally regulated by Pax8 as well as infer its direct targets, we performed RNAi to knock-down Pax8 gene in FRTL-5 thyroid cells. Expression data from three independent silencing experiments were analyzed by microarray technology unraveling 2815 genes differentially expressed between silenced cells and controls. Of these, 1421 genes were down-regulated and 1394 genes were up-regulated 72hrs after Pax8 silencing.
Identification of novel Pax8 targets in FRTL-5 thyroid cells by gene silencing and expression microarray analysis.
Cell line
View SamplesIn contrast to the migration of leukocytes from blood vessels into tissues, and the involvement of adhesion molecules and chemokines in this process, the migration of leukocytes from the tissue into lymphatic vessels is much less well understood. This can, in part be explained by the fact that murine lymphatic endothelial cells (LECs) have proven particularly hard to isolate and propagate in culture. Hence, it has been difficult to establish suitable models to study this process in vitro. Combining magnetic bead-based purification and fluorescence-activated cell sorting (FACS), we have isolated LECs (immorto-LECs) from the skin of mice which express a temperature-sensitive SV40 large T antigen (H-2Kb-tsA58 mice; ImmortoMice) in all cell types under the control of the MHC-class-I-promotor, H-2Kb. The isolated cells are viable for more than 30 passages when cultured at 33 C, the temperature at which the large T antigen is stably expressed. Furthermore, immorto-LECs tolerate several days of culture at 37 C, but become senescent if continuously cultured at this temperature. All cells stably express endothelial and lymphatic markers like CD31, podoplanin, Prox-1 and VEGFR-3 up to passage 30. When cultured in presence of tumor necrosis factor-alpha (TNF-a), immorto-LECs upregulate adhesion molecules, such as ICAM-1, VCAM-1 and E-selectin, similarly to what has been reported to occur under inflammatory conditions in vivo. Overall, our findings establish immorto-LECs as a useful and handy tool for the in vitro investigation of immune cell transmigration across lymphatic endothelium.
Tissue inflammation modulates gene expression of lymphatic endothelial cells and dendritic cell migration in a stimulus-dependent manner.
Specimen part
View SamplesThe AIL transcription factor BABY BOOM (BBM) is required together with the related PLETHORA proteins for embryo and root meristem development and its expression is sufficient to confer pluripotency and totipotency to somatic tissues. We show that BBM and other AIL proteins interact with multiple members of the L1/epidermal-expressed HD-ZIP class IV / HOMEODOMAIN GLABROUS (HDG) transcription factor family. Ectopic overexpression of HDG1, HDG11 and HDG12 genes induces a reduced growth phenotype, and analysis of HDG1 overexpression lines shows that this growth reduction is due to both root and shoot meristem arrest. To understand how HDG1 controls cell proliferation, as well as its functional relationship with BBM, we performed microarray experiments to identify candidate genes that are directly regulated by HDG1, and compared these to the set of genes that are directly regulated by BBM expression.
AIL and HDG proteins act antagonistically to control cell proliferation.
Specimen part, Treatment
View SamplesThe transcription factor SRF (serum response factor) mediates epilepsy mediated gene expression
SRF modulates seizure occurrence, activity induced gene transcription and hippocampal circuit reorganization in the mouse pilocarpine epilepsy model.
Specimen part, Treatment
View Samples