Targeting the Mdm2 oncoprotein by drugs has the potential of re-establishing p53 function and tumor suppression. However, Mdm2-antagonizing drug candidates, e. g. Nutlin-3a, often fail to abolish cancer cell growth sustainably. To overcome these limitations, we inhibited Mdm2 and simultaneously a second negative regulator of p53, the phosphatase Wip1/PPM1D. When combining Nutlin-3a with the Wip1 inhibitor GSK2830371 in the treatment of p53-proficient but not p53-deficient cells, we observed enhanced phosphorylation (Ser 15) and acetylation (Lys 382) of p53, increased expression of p53 target gene products, and synergistic inhibition of cell proliferation. Surprisingly, when testing the two compounds individually, largely distinct sets of genes were induced, as revealed by deep sequencing analysis of RNA. In contrast, the combination of both drugs led to an expression signature that largely comprised that of Nutlin-3a alone. Moreover, the combination of drugs, or the combination of Nutlin-3a with Wip1-depletion by siRNA, activated p53-responsive genes to a greater extent than either of the compounds alone. Simultaneous inhibition of Mdm2 and Wip1 enhanced cell senescence and G2/M accumulation. Taken together, the inhibition of Wip1 might fortify p53-mediated tumor suppression by Mdm2 antagonists. Overall design: Expression profiling by high throughput sequencing
Cooperation of Nutlin-3a and a Wip1 inhibitor to induce p53 activity.
Specimen part, Treatment, Subject
View SamplesWe examined transcriptome-wide effects of 4SC-202 in L3.6, BXPC3 and PANC1 cells as well as its effect on TGFß signaling Overall design: We performed mRNA sequencing from L3.6, BXPC3 and PANC1 cells following following DMSO, 4SC-202 and/or TGFß treatment. The mRNA-Seq includes following conditions: 4SC-202 vs DMSO (for L3.6, BXPC3 and PANC1 cells), TGFß vs DMSO and 4SC-202+TGFß vs TGFß (for PANC1 cells). The libraries were performed in triplicates.
Histone deacetylase class-I inhibition promotes epithelial gene expression in pancreatic cancer cells in a BRD4- and MYC-dependent manner.
Cell line, Subject
View SamplesWe examined context specific function of BRD4 in promoting lineage specific gene expression and show that BRD4 is essential for osteoblast differentiation. Overall design: We performed mRNA sequencing from hFOB cells (undifferentiated and differentiated for 5 days into osteoblastic lineage) following BRD4 inhibition by JQ1 or siRNA mediated depletion. The mRNA-Seq includes namely 7 conditions: undifferentiated hFOBs treated with DMSO or non-targeting control siRNA (siCNTR), differentiated hFOBs with DMSO or siCNTR treatments; differentiated hFOBs treated with JQ1 or two siRNAs against BRD4 (#3 & #4). The libraries were performed in triplicates.
BRD4 localization to lineage-specific enhancers is associated with a distinct transcription factor repertoire.
Specimen part, Treatment, Subject
View SamplesThe Mdm2 oncoprotein ubiquitinates and antagonizes p53 but may also carry out p53-independent functions. Here we report that Mdm2 is required for the efficient generation of induced pluripotent stem cells (iPSCs) from murine embryonic fibroblasts, in the absence of p53. Similarly, Mdm2 depletion in the context of p53 deficiency also promoted the differentiation of human mesenchymal stem cells and diminished clonogenic survival of cancer cells. Most of the Mdm2-controlled genes also responded to the inactivation of the Polycomb Repressor Complex 2 (PRC2) and its catalytic component EZH2. Mdm2 physically associated with EZH2 on chromatin, enhancing the trimethylation of Histone 3 at lysine 27 and the ubiquitination of Histone 2A at lysine 119 (H2AK119) at its target genes. Removing Mdm2 simultaneously with the H2AK119 E3 ligase Ring1B/RNF2 further induced these genes and synthetically arrested cell proliferation. In conclusion, Mdm2 supports the Polycomb-mediated repression of lineage specific genes independent of p53. Overall design: Expression profiling by high throughput sequencing of p53 ko MEFs, p53Mdm2 ko MEFs, p53ko Mdm2 C462A ki MEFs.
MDM2 Associates with Polycomb Repressor Complex 2 and Enhances Stemness-Promoting Chromatin Modifications Independent of p53.
Specimen part, Cell line, Subject
View SamplesThe estrogen receptor-a (ERa) is a transcription factor which plays a critical role in controlling cell proliferation and tumorigenesis by recruiting various cofactors to estrogen response elements (EREs) to induce or repress gene transcription. A deeper understanding of these transcriptional mechanisms may uncover novel therapeutic targets for ERa-dependent cancers. Here we show for the first time that BRD4 regulates ERa-induced gene expression by affecting elongation-associated phosphorylation of RNA Polymerase II (RNAPII P-Ser2) and histone H2B monoubiquitination (H2Bub1). Consistently, BRD4 activity is required for estrogen-induced proliferation of ER+ breast and endometrial cancer cells and uterine growth in mice. Genome-wide occupancy studies revealed an enrichment of BRD4 on transcriptional start sites as well as EREs enriched for H3K27ac and demonstrate a requirement for BRD4 for H2B monoubiquitination in the transcribed region of estrogen-responsive genes. Importantly, we further demonstrate that BRD4 occupancy correlates with active mRNA transcription and is required for the production of ERa-dependent enhancer RNAs (eRNAs). These results uncover BRD4 as a central regulator of ERa function and potential therapeutic target. Overall design: mRNA expression profiles of MCF7 cells treated with +/- estrogen treatment under negative control siRNA, BRD4 siRNA or JQ1 treatment, in duplicates.
Bromodomain protein BRD4 is required for estrogen receptor-dependent enhancer activation and gene transcription.
No sample metadata fields
View SamplesBromodomain-containing protein 4 (BRD4) is an important epigenetic reader which promotes gene transcription to modulate cell-specific functions and is under intensive investigation for its potential as an anti-tumor therapeutic target. However, the role of BRD4 in non-transformed cells remains unclear. Here we demonstrate that BRD4 is required for the expression of epithelial-specific genes and suppression of stem cell-like properties by binding to the distal regions of epithelial-related genes. Moreover, BRD4 occupancy correlates with enhancer activity and enhancer RNA (eRNA) transcription of epithelial differentiation-specific genes. Interestingly, we show that BRD4 perturbation regulates the expression of Grainy Head-like transcription factor, GRHL3, whose depletion partially mimics BRD4 inhibition and blocks differentiated phenotype. By binding to the distal regions of GRHL3, BRD4 promotes RNA polymerase-II occupancy and thus affects eRNA transcription. Altogether, these findings provide evidence that BRD4 promotes a differentiated epithelial phenotype in non-transformed mammary cells at least in part through the activation of GRHL3 expression. Overall design: mRNA expression profiles of MCF10A cells under negative control siRNA, BRD4 siRNA or JQ1 treatment, in duplicates.
BRD4 promotes p63 and GRHL3 expression downstream of FOXO in mammary epithelial cells.
No sample metadata fields
View SamplesEndogenous pancreatic multipotent progenitors (PMPs) are ideal candidates for regenerative approaches to compensate for b-cell loss since their b-cell–producing capacities as well as strategic location would eliminate unnecessary invasive manipulations. However, little is known about the status and potentials of PMPs under diabetic conditions. Here we show that b-cell metabolic stress and hyperglycemia enhance the proliferation capacities of adult PMP cells and bias their production of progeny toward b-cells in mouse and human. These effects are dynamic and correlate with functional b-cell regeneration when conditions allow. Overall design: Insulin-positive Glut2-low cell population of adult pancreatic tissue is enriched for PMP cells. Streptozocin (STZ) can enter beta-cells via Glut2 , induce cell death and consequently diabetes. Insulin-positive cells from two groups (STZ-injected experiment and vehicle-injected control, n=3/group) of MIP-GFP transgenic male mice were sorted to Glut2-low (Glut2L) and Glut2-high (Glut2H) by FACS. Total RNA from these samples were extracted for transcriptome analysis.
Diabetes enhances the proliferation of adult pancreatic multipotent progenitor cells and biases their differentiation to more β-cell production.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Combined chromatin and expression analysis reveals specific regulatory mechanisms within cytokine genes in the macrophage early immune response.
Cell line
View SamplesMacrophages play a critical role in innate immunity, and the expression of early response genes orchestrate much of the initial response of the immune system. Macrophages undergo extensive transcriptional reprogramming in response to inflammatory stimuli such as Lipopolysaccharide (LPS). To identify gene transcription regulation patterns involved in early innate immune responses, we used two genome-wide approaches - gene expression profiling and chromatin immunoprecipitation-sequencing (ChIP-seq) analysis. We examined the effect of 2 hrs LPS stimulation on early gene expression and its relation to chromatin remodeling (H3 acetylation; H3Ac) and promoter binding of Sp1 and RNA polymerase II phosphorylated at serine 5 (S5P RNAPII), which is a marker for transcriptional initiation. Our results indicate novel and alternative gene regulatory mechanisms for certain proinflammatory genes. We identified two groups of up-regulated inflammatory genes with respect to chromatin modification and promoter features. One group, including highly up-regulated genes such as tumor necrosis factor (TNF), was characterized by H3Ac, high CpG content and lack of TATA boxes. The second group, containing inflammatory mediators (interleukins and CCL chemokines), was up-regulated upon LPS stimulation despite lacking H3Ac in their annotated promoters, which were low in CpG content but did contain TATA boxes. Genome-wide analysis showed that few H3Ac peaks were unique to either +/-LPS condition. However, within these, an unpacking/expansion of already existing H3Ac peaks was observed upon LPS stimulation. In contrast, a significant proportion of S5P RNAPII peaks (approx 40%) was unique to either condition. Furthermore, data indicated a large portion of previously unannotated TSSs, particularly in LPS-stimulated macrophages, where only 28% of unique S5P RNAPII peaks overlap annotated promoters. The regulation of the inflammatory response appears to occur in a very specific manner at the chromatin level for specific genes and this study highlights the level of fine-tuning that occurs in the immune response.
Combined chromatin and expression analysis reveals specific regulatory mechanisms within cytokine genes in the macrophage early immune response.
Cell line
View SamplesTacrolimus and Sirolimus are commonly used to maintain immunosuppression in kidney transplantation. However, their effects on immune cells and allograft molecular profiles have not been elucidated.
Cellular and molecular immune profiles in renal transplant recipients after conversion from tacrolimus to sirolimus.
Specimen part, Treatment
View Samples