Overexpression of the Polycomb group protein Enhancer of Zeste Homolog 2 (EZH2) occurs in diverse malignancies, including prostate cancer, breast cancer, and glioblastoma multiforme (GBM) (1). Based on its ability to modulate transcription of key genes implicated in cell cycle control, DNA repair and cell differentiation, EZH2 is believed to play a crucial role in tissue-specific stem cell maintenance and tumor development. Here we show that targeted pharmacologic disruption of EZH2 by the S-adenosylhomocysteine hydrolase inhibitor 3-Deazaneplanocin A (DZNep), or its specific down-regulation by shRNA, strongly impairs GBM cancer stem cell self-renewal in vitro and tumor-initiating capacity in vivo. Using genome-wide expression analysis of DZNep-treated GBM cancer stem cells, we found the expression of c-myc, recently reported to be essential for GBM cancer stem cells, to be strongly repressed upon EZH2 depletion. Specific shRNA-mediated down-regulation of EZH2 in combination with chromatin immunoprecipitation (ChIP) experiments revealed that c-myc is a direct target of EZH2 in GBM cancer stem cells. Taken together, our observations provide evidence that direct transcriptional regulation of c-myc by EZH2 may constitute a novel mechanism underlying GBM cancer stem cell maintenance and suggest that EZH2 may be a valuable new therapeutic target for GBM management.
EZH2 is essential for glioblastoma cancer stem cell maintenance.
Specimen part, Treatment
View SamplesCancer stem cells (CSCs) display plasticity and self-renewal properties reminiscent of normal tissue stem cells, but the events responsible for their emergence remain obscure. We recently identified CSCs in Ewing sarcoma family tumors (ESFTs) and showed that they retain mesenchymal stem cell (MSC) plasticity. In the present study, we addressed the mechanisms that underlie ESFT CSC development. We show that the EWS-FLI-1 fusion gene, associated with 85%-90% of ESFTs and believed to initiate their pathogenesis, induces expression of the embryonic stem cell (ESC) genes OCT4, SOX2, and NANOG in human pediatric MSCs (hpMSCs) but not in their adult counterparts. Moreover, under appropriate culture conditions, hpMSCs expressing EWS-FLI-1 generate a cell subpopulation displaying ESFT CSC features in vitro. We further demonstrate that induction of the ESFT CSC phenotype is the result of the combined effect of EWS-FLI-1 on its target gene expression and repression of microRNA-145 (miRNA145) promoter activity. Finally, we provide evidence that EWS-FLI-1 and miRNA-145 function in a mutually repressive feedback loop and identify their common target gene, SOX2, in addition to miRNA145 itself, as key players in ESFT cell differentiation and tumorigenicity. Our observations provide insight for the first time into the mechanisms whereby a single oncogene can reprogram primary cells to display a CSC phenotype.
EWS-FLI-1 modulates miRNA145 and SOX2 expression to initiate mesenchymal stem cell reprogramming toward Ewing sarcoma cancer stem cells.
Specimen part
View SamplesTriple negative breast cancer (TNBC) is a heterogeneous and clinically aggressive disease for which there is no targeted therapy. Here we report the preferential and high sensitivity of TNBCs to BET bromodomain inhibitors such as JQ1 manifested by cell cycle arrest in early G1, apoptosis, and induction of markers of luminal epithelial differentiation in vitro and in vivo. The sensitivity of TNBC and other tumor types to BET inhibition establishes a rationale for clinical investigation, and a motivation to understand mechanisms of resistance. After engendering acquired resistance to BET inhibition in previously sensitive TNBCs, we utilized integrative approaches to identify a unique mechanism of epigenomic resistance to this epigenetic therapy. Resistant cells remain dependent on BRD4, confirmed by RNA interference. However, TNBC cells adapt to BET bromodomain inhibition by re-recruitment of unmutated BRD4 to super-enhancers, now in a bromodomain-independent manner. Proteomic studies of resistant TNBC identify hyper-phosphorylation of BRD4 and strong association with MED1. Together, these studies provide a rationale for BET inhibition in TNBC and argue for combination strategies to anticipate clinical drug resistance. Overall design: RNA-Seq in parental and JQ1 resistant triple negative breast cancer (TNBC) in response to DMSO or JQ1 treatment over time
Response and resistance to BET bromodomain inhibitors in triple-negative breast cancer.
No sample metadata fields
View SamplesThe aim was to identify transcripts that are poorly translated upon knockdown of DENR. Lysates from control (GFP) and DENR knockdown S2 cells were run on polysome gradients.
DENR-MCT-1 promotes translation re-initiation downstream of uORFs to control tissue growth.
Specimen part, Disease, Treatment
View SamplesBackground: Studies in mice have shown that PPAR is an important regulator of lipid metabolism in liver and a key transcription factor involved in the adaptive response to fasting. However, much less is known about the role of PPAR in human liver. Here we set out to study the function of PPAR in human liver via analysis of whole genome gene regulation in human liver slices treated with the PPAR agonist Wy14643.
The impact of PPARα activation on whole genome gene expression in human precision cut liver slices.
Sex, Specimen part, Treatment, Subject, Time
View SamplesAutism spectrum disorders (ASD) are a group of genetic disorders often overlapping with other neurological conditions. We previously described abnormalities in the branched chain amino acid (BCAA) catabolic pathway as a cause of ASD. Here we show that the solute carrier transporter 7a5 (SLC7A5), a large neutral amino acid transporter localized at the blood brain barrier (BBB), has an essential role in maintaining normal levels of brain BCAAs. In mice, deletion of Slc7a5 from the endothelial cells of the BBB leads to decreased levels of brain BCAAs, abnormal mRNA translation and severe neurological abnormalities. Furthermore, we identified several patients with autistic traits and motor delay carrying deleterious homozygous mutations in the SLC7A5 gene. Finally, we demonstrate that BCAA intracerebroventricular administration ameliorates abnormal behaviors in adult mutant mice. Our data elucidate a neurological syndrome defined by SLC7A5 mutations and support an essential role for the BCAA in human brain function. Overall design: RNA-sequencing of cerebellum from 3 wildtype mice and 3 Slc7a5 KO mice
Impaired Amino Acid Transport at the Blood Brain Barrier Is a Cause of Autism Spectrum Disorder.
Specimen part, Subject
View SamplesLittle is known about the early transcriptional events in innate immune signaling in immature and tolerogenic monocyte-derived dendritic cells (DCs), the professional antigen-presenting cells of our immune system. TLR ligands usually induce a proinflammatory transcriptional response, whereas IL10 and/or dexamethasone induce a more tolerogenic phenotype.
MicroRNA genes preferentially expressed in dendritic cells contain sites for conserved transcription factor binding motifs in their promoters.
Specimen part
View SamplesBACKGROUND: The daily gene expression oscillations that underlie mammalian circadian rhythms show striking differences between tissues and involve post-transcriptional regulation. Both aspects remain poorly understood. We have used ribosome profiling to explore the contribution of translation efficiency to temporal gene expression in kidney, and contrasted our findings with liver data available from the same mice. RESULTS: Rhythmic translation of constantly abundant mRNAs affects largely nonoverlapping transcript sets with distinct phase clustering in the two organs. Moreover, tissue differences in translation efficiency modulate the timing and amount of protein biosynthesis from rhythmic mRNAs, consistent with organ-specificity in clock output gene repertoires and rhythmicity parameters. Our comprehensive datasets provided insights into translational control beyond temporal regulation. Between tissues, many transcripts show differences in translation efficiency, which are, however, of markedly smaller scale than mRNA abundance differences. Tissue-specific changes in translation efficiency are associated with specific transcript features and, intriguingly, globally counteracted and compensated transcript abundance variations, leading to higher similarity at the level of protein biosynthesis between both tissues. CONCLUSIONS: We show that tissue-specificity in rhythmic gene expression extends to the translatome and contributes to define the identities, the phases and the expression levels of rhythmic protein biosynthesis. Moreover, translational compensation of transcript abundance divergence leads to overall higher similarity at the level of protein production across organs. The unique resources provided through our study will serve to address fundamental questions of post-transcriptional control and differential gene expression in vivo. Overall design: A total of 48 mice were entrained under 12hours light:dark conditions for 2 weeks and also collected under 12hours light:dark. Mice were sacrificed every two hours during the 24 hours daily cycle. Two replicates per time point, each replicate is a pool of livers or kidneys from 2 animals.
Translational contributions to tissue specificity in rhythmic and constitutive gene expression.
Sex, Cell line, Subject, Time
View SamplesGENES ASSOCIATED WITH THE CELL CYCLE, LINEAGE COMMITMENT AND IMMUNOMODULATORY POTENTIAL DISCRIMINATE HUMAN POSTNATAL STEM CELLS OF DIFFERENT ORIGIN.
Functional differences between mesenchymal stem cell populations are reflected by their transcriptome.
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View SamplesMutants in the Drosophila gene lethal (3) malignant brain tumor cause malignant growth in the larval brain. This data shows the changes in gene expression profile associated to mutations in l(3)mbt, both in situ in third instar larval brains and in tumors cultured for 1 5 and 10 (T1, T5, T10) rounds of allograft culture
Ectopic expression of germline genes drives malignant brain tumor growth in Drosophila.
No sample metadata fields
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