Purpose: Transcriptome analysis of ESR1 mutant cells was performed via sequencing total RNA in T47D and MCF7 cell lines containing Y537S and D538G mutations. Overall design: Methods: Individual ESR1 WT and mutant T47D and MCF7 clones were hormone deprived in CSS for three days, pooled, and plated in quadruplicates in 6-well plates. The cells were treated with veh or 1nM E2 for 24 hrs, RNA was isolated and subjected to sequencing. Differential expression analysis was performed by DEseq2 and R was used to conduct statistical analysis tests
Mutation site and context dependent effects of ESR1 mutation in genome-edited breast cancer cell models.
Treatment, Subject
View SamplesCellular senescence is a homeostatic program associated with tumor suppression, wound healing, and certain age related pathologies. Senescent cells display a repressive chromatin configuration thought to stably silence proliferation-promoting genes, while at the same time activate an unusual form of immune surveillance involving a secretory program referred to as the senescence-associated secretory phenotype (SASP). Here we demonstrate that senescence also involves a global remodeling of the enhancer landscape with recruitment of the chromatin reader BRD4 to newly activated super-enhancers adjacent to key SASP genes. Transcriptional profiling and functional studies indicate that BRD4 is required for the SASP and downstream paracrine signaling. Consequently, BRD4 inhibition disrupts immune cell-mediated targeting and elimination of premalignant senescent cells in vitro and in vivo. Our results identify a critical role for BRD4-bound super-enhancers in senescence immune surveillance and in the proper execution of a tumor-suppressive program. Overall design: Analysis of RNA isolated from human fibroblasts (IMR90) in proliferating, quiescent or senescent (HrasV12) conditions upon knockdown of Brd4, p65, p53, p53/RB, p16/21 or Vehicle and JQ1 treatment
BRD4 Connects Enhancer Remodeling to Senescence Immune Surveillance.
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View SamplesAutophagy is a membrane-trafficking process that directs degradation of cytoplasmic material in lysosomes. The process promotes cellular fidelity, and while the core machinery of autophagy is known, the mechanisms that promote and sustain autophagy are less well defined. Here we report that the epigenetic reader BRD4 and the methyltransferase G9a repress a TFEB/TFE3/MITF-independent transcriptional program that promotes autophagy and lysosome biogenesis. We show that BRD4 knockdown induces autophagy in vitro and in vivo in response to some, but not all, situations. In the case of starvation, a signaling cascade involving AMPK and histone deacetylase SIRT1 displaces chromatin-bound BRD4, instigating autophagy gene activation and cell survival. Importantly, this program is directed independently and also reciprocally to the growth-promoting properties of BRD4 and is potently repressed by BRD4-NUT, a driver of NUT midline carcinoma. These findings therefore identify a distinct and selective mechanism of autophagy regulation. Overall design: RNA-Seq of KP-4 pancreatic adenocarcinoma cells transfected with control, BRD4 #1 or BRD4 #2 siRNA for 72hrs (n=3 independent sample preparations)
Bromodomain Protein BRD4 Is a Transcriptional Repressor of Autophagy and Lysosomal Function.
Specimen part, Subject
View SamplesGene fusions arising from chromosomal translocations are key oncogenic drivers in soft tissue sarcomas but little is known about how they exert their oncogenic effects. Our study explores the molecular mechanisms by which the SS18-SSX fusion oncoprotein subverts epigenetic mechanisms of gene regulation to drive synovial sarcoma. Using functional genomics, we identify KDM2B – a histone demethylase and core component of a non-canonical Polycomb Repressive Complex 1 (PRC1.1) – as selectively required for sustaining synovial sarcoma cell transformation. SS18-SSX physically interacts with PRC1.1 and co-associates with SWI/SNF and KDM2B complexes on unmethylated CpG islands genome-wide. Via KDM2B, SS18-SSX binds and aberrantly activates expression of a series of developmentally regulated transcription factors that would otherwise be targets of polycomb-mediated repression, which is restored upon KDM2B depletion leading to irreversible mesenchymal differentiation. Thus, SS18-SSX de-regulates developmental programs to drive transformation by hijacking a transcriptional repressive complex to aberrantly activate gene expression. Overall design: RNA-Seq of human synovial sarcoma cells (HS-SY-II) in control cells (Ren.173) and upon knockdown of SS18-SSX1 (SS18.273 and SSX.1274) or of KDM2B (KDM2B. 4395 and KDM2B.4835) in duplicates.
The SS18-SSX Oncoprotein Hijacks KDM2B-PRC1.1 to Drive Synovial Sarcoma.
Subject
View SamplesThe Drosophila midgut is an ideal model system to study molecular mechanisms that interfere with the intestinal stem cells’ (ISCs) ability to function in tissue homeostasis. Due to the lack of a combination of molecular markers suitable to isolate ISCs from aged intestines, it has been a major challenge to study endogenous molecular changes of ISCs during aging. Our FACS-based approach using the esg-GAL4, UAS-GFP fly line allowed the isolation of a cell population enriched for ISCs from young and old midguts by their small size, little granularity and low GFP intensity. The isolated ISCs were subsequently used for RNA sequencing to identify endogenous changes in the transcriptome of young versus old ISCs. Overall design: Cell populations enriched for ISCs isolated from young (6-8 days old) and old (59-65 days old) midguts were sorted. Cells from three different batches of young and old midguts were subjected to Next Generation Sequencing using Illumina Genome Analyzer IIx.
Nipped-A regulates intestinal stem cell proliferation in <i>Drosophila</i>.
Age, Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The histone chaperone CAF-1 safeguards somatic cell identity.
Specimen part, Time
View SamplesCellular differentiation involves profound changes in the chromatic landscape, yet the mechanisms by which somatic cell identity is subsequently maintained remain incompletely understood. To further elucidate regulatory pathways that safeguard the somatic state, we performed two comprehensive RNAi screens targeting chromatin factors during transcription factor-mediated reprogramming of mouse fibroblasts to induced pluripotent stem cells (iPSCs). Remarkably, subunits of the chromatin assembly factor-1 (CAF-1) complex emerged as the most prominent hits from both screens, followed by modulators of lysine sumoylation and heterochromatin maintenance. Suppression of CAF-1 increased reprogramming efficiency by several orders of magnitude and facilitated iPSC formation in as little as 4 days. Mechanistically, CAF-1 suppression led to a more accessible chromatin structure at enhancer elements early during reprogramming. These changes were accompanied by a decrease in somatic heterochromatin domains, increased binding of Sox2 to pluripotency-specific targets and activation of associated genes. Notably, suppression of CAF-1 also enhanced the direct conversion of B cells into macrophages and fibroblasts into neurons. Together, our findings reveal the histone chaperone CAF-1 as a novel regulator of somatic cell identity during transcription factor-induced cell fate transitions and provide a potential strategy to modulate cellular plasticity in a regenerative setting.
The histone chaperone CAF-1 safeguards somatic cell identity.
Specimen part, Time
View SamplesDifferentially expressed genes along the paraxial mesoderm of 12 somite stage zebrafish embryos are identified
Spatiotemporal compartmentalization of key physiological processes during muscle precursor differentiation.
Specimen part
View SamplesWe previously isolated a subclone, MIN6 clone 4, from the parental MIN6 cells, that shows well-regulated insulin secretion in response to glucose, glybenclamide, and KCl, even after prolonged culture. To investigate the molecular mechanisms responsible for preserving GSIS in this subclone, we compared four groups of MIN6 cells: Pr-LP (parental MIN6, low passage number), Pr-HP (parental MIN6, high passage number), C4-LP (MIN6 clone 4, low passage number), and C4-HP (MIN6 clone 4, high passage number). Based on their capacity for GSIS, we designated the Pr-LP, C4-LP, and C4-HP cells as responder cells. In a DNA microarray analysis, we identified a group of genes with high expression in responder cells (responder genes), but extremely low expression in the Pr-HP cells.
Microarray analysis of novel candidate genes responsible for glucose-stimulated insulin secretion in mouse pancreatic β cell line MIN6.
Cell line
View SamplesThe supraoptic nucleus (SON) of the hypothalamus is an important integrative brain structure that co-ordinates responses to perturbations in water balance and regulates maternal physiology through the release of the neuropeptide hormones vasopressin and oxytocin into the circulation. Both dehydration and lactation evoke a dramatic morphological remodelling of the SON, a process known as function-related plasticity. We hypothesise that some of the changes seen in SON remodelling are mediated by differential gene expression, and have thus used microarrays to document global changes in transcript abundance that accompany chronic dehydration in female rats, and in lactation. In situ hydridisation analysis has confirmed the differential expression of 3 of these genes, namely Tumour necrosis factor induced protein 6, Gonadotrophin inducible transcription factor 1 and Ornithine decarboxylase antizyme inhibitor 1. Comparison of differential gene expression patterns in male and female rats subjected to dehydration and in lactating rats has enabled the identification of common elements that are significantly enriched in gene classes with particular functions. Two of these are related to the requirement for increased protein synthesis and hormone delivery in the physiologically stimulated SON (translation initiation factor activity and endoplasmic reticulum-Golgi intermediate compartment respectively), whilst others are consistent with concept of SON morphological plasticity (collagen fibril organisation, extracellular matrix organization and biogenesis, extracellular structure organization and biogenesis and homophilic cell adhesion). We suggest that the genes co-ordinately regulated in the SON as a consequence of dehydration and lactation form a network that mediates the plastic processes operational in the physiologically activated SON.
Transcriptomic analysis of the osmotic and reproductive remodeling of the female rat supraoptic nucleus.
Sex, Specimen part, Treatment
View Samples