This SuperSeries is composed of the SubSeries listed below.
PRC2 loss amplifies Ras-driven transcription and confers sensitivity to BRD4-based therapies.
Cell line, Treatment
View SamplesThe polycomb repressive complex 2 (PRC2) exerts oncogenic effects in many tumour types1. However, loss-of-function mutations in PRC2 components occur in a subset of haematopoietic malignancies, sug- gesting that this complex plays a dichotomous and poorly understood role in cancer2,3. Here we provide genomic, cellular, and mouse mod- elling data demonstrating that the polycomb group gene SUZ12 func- tions as tumour suppressor in PNS tumours, high-grade gliomas and melanomas by cooperating with mutations in NF1. NF1 encodes a Ras GTPase-activating protein (RasGAP) and its loss drives cancer by activating Ras4. We show that SUZ12 loss potentiates the effects of NF1 mutations by amplifying Ras-driven transcription through effects on chromatin. Importantly, however, SUZ12 inactivation also triggers an epigenetic switch that sensitizes these cancers to bromodomain inhib- itors. Collectively, these studies not only reveal an unexpected con- nection between the PRC2 complex, NF1 and Ras, but also identify a promising epigenetic-based therapeutic strategy that may be exploited for a variety of cancers.
PRC2 loss amplifies Ras-driven transcription and confers sensitivity to BRD4-based therapies.
Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Comparing effects of mTR and mTERT deletion on gene expression and DNA damage response: a critical examination of telomere length maintenance-independent roles of telomerase.
Sex, Specimen part
View SamplesTelomerase, the essential enzyme that maintains telomere length, contains two core components, TERT and TR. While early studies in yeast and mouse both indicated that loss of telomerase leads to phenotypes that arise after an increased number of generations, due to telomere shortening, recent studies claim additional roles for telomerase components in transcription and the response to DNA damage. To test these telomere length maintenance-independent roles of telomerase components, we examined first generation mTR-/- and mTERT-/- mice with long telomeres. We used gene expression profiling and found no genes that were expressed at significantly different levels when independent mTR-/- G1 mice were compared to mTERT-/- G1 mice and to wild-type mice. In addition, we compared the response to DNA damage in mTR-/-G1 and mTERT-/- G1 mouse embryonic fibroblasts, and found no increase in the response to DNA damage in the absence of either telomerase components compared to wild-type. We conclude that in the wild-type physiological telomere length setting, neither mTR nor mTERT act as a transcription factor or have a role in the DNA damage response.
Comparing effects of mTR and mTERT deletion on gene expression and DNA damage response: a critical examination of telomere length maintenance-independent roles of telomerase.
Sex, Specimen part
View SamplesTelomerase, the essential enzyme that maintains telomere length, contains two core components, TERT and TR. While early studies in yeast and mouse both indicated that loss of telomerase leads to phenotypes that arise after an increased number of generations, due to telomere shortening, recent studies claim additional roles for telomerase components in transcription and the response to DNA damage. To test these telomere length maintenance-independent roles of telomerase components, we examined first generation mTR-/- and mTERT-/- mice with long telomeres. We used gene expression profiling and found no genes that were expressed at significantly different levels when independent mTR-/- G1 mice were compared to mTERT-/- G1 mice and to wild-type mice. In addition, we compared the response to DNA damage in mTR-/-G1 and mTERT-/- G1 mouse embryonic fibroblasts, and found no increase in the response to DNA damage in the absence of either telomerase components compared to wild-type. We conclude that in the wild-type physiological telomere length setting, neither mTR nor mTERT act as a transcription factor or have a role in the DNA damage response.
Comparing effects of mTR and mTERT deletion on gene expression and DNA damage response: a critical examination of telomere length maintenance-independent roles of telomerase.
Sex, Specimen part
View SamplesUsing RNA-seq we characterized gene expression changes occuring upon knockout of EZH2, EZH1, EZH1+EZH2 or SUZ12 in a neurofibroma cell line. We also investigated the transcriptional consequences of EZH1+EZH2 double knockout in a SUZ12-mutant MPNST cell line. Overall design: Examination of transcript abundance in wild-type and mutant ipNF05.5 or 88.14 cells. Two biological replicates were performed for wild-type and mutant ipNF05.5 cell lines. Three biological replicates were performed for wild-type and mutant 88.14 cell lines.
EZH1/2 function mostly within canonical PRC2 and exhibit proliferation-dependent redundancy that shapes mutational signatures in cancer.
Cell line, Subject
View SamplesAlterations of chromatin modifiers are frequent in cancer but their functional consequences remain often unclear. Focusing on the Polycomb protein EZH2 that deposits H3K27me3 mark, we showed that its high expression in solid tumors is a consequence, and not a cause, of tumorigenesis. In mouse and human models, EZH2 is dispensable for prostate cancer development and restrains breast tumorigenesis. High EZH2 expression in tumors results from a tight coupling to proliferation to ensure H3K27me3 homeostasis. However, this process is malfunctioning in breast cancer. Low EZH2 expression relative to proliferation and mutations in Polycomb genes are actually of poor prognosis and occur in metastases. We show that while altered EZH2 activity consistently modulates a subset of its target genes, it promotes a wider transcriptional instability. Importantly, transcriptional changes consequent to EZH2 loss are predominantly irreversible. Our study provides an unexpected understanding of EZH2's contribution to solid tumors with important therapeutic implications.
Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis.
Specimen part
View SamplesPolycomb Repressive Complex 2 (PRC2) plays a key role in controlling transcriptional repression. It is thought to act at the level of the chromatin, where its enzymatic subunits Ezh1 and Ezh2 catalyse the di/tri-methylation of histone H3 on its lysine 27 (H3K27me3).
Impaired PRC2 activity promotes transcriptional instability and favors breast tumorigenesis.
Specimen part
View SamplesCCAAT/enhancer binding protein ß (C/EBPß) is a transcription factor that regulates the expression of important pro-inflammatory genes in microglia. Mice deficient for C/EBPß show protection against excitotoxic and ischemic CNS damage but the involvement of the various C/EBPß expressing cell types in this neuroprotective effect is not solved. Since C/EBPß-deficient microglia show attenuated neurotoxicity in culture we hypothesized that specific C/EBPß deficiency in microglia could be neuroprotective in vivo. In this study we have tested this hypothesis by generating mice with myeloid C/EBPß deficiency. Mice with myeloid C/EBPß deficiency were generated by crossing LysMCre and C/EBPßfl/fl mice . Primary microglial cultures from C/EBPßfl/fl (named here as WT) and LysMCre-C/EBPßfl/fl (named here as KO) mice were treated with lipopolysaccharide ± interferon ? (IFN?) for 6 h and gene expression was analyzed by RNA sequencing. LysMCre-C/EBPßfl/fl mice showed an efficiency of C/EBPß deletion of 100% in cultured microglia. Transcriptomic analysis of C/EBPß-deficient primary microglia revealed C/EBPß-dependent expression of 1068 genes, significantly enriched in inflammatory and innate immune responses GO terms. This study provides new data that support a central role for C/EBPß in the biology of activated microglia. Overall design: LysMCre-C/EBPßfl/fl genotype (12 samples): 4 samples treated with LPS, 4 with LPS +IFNg, and 4 vehicle. C/EBPßfl/fl genotype (9 samples): 3 samples treated with LPS, 3 with LPS +IFNg, and 3 vehicle. Design Case (Treatment LPS or LPS +INF) control (No treatment or vehicle) in LysMCre-C/EBPßfl/fl genotype and in C/EBPßfl/fl genotype
RNA-Seq transcriptomic profiling of primary murine microglia treated with LPS or LPS + IFNγ.
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View SamplesAuxin is a key phytohormone regulating central processes in plants that include embryo development, lateral root growth and flower maturation among others. Auxin is sensed by a set of F-Box proteins of the TIR1/AFB3 family triggering auxin dependent responses by a pathway that involves an interplay between the Aux/IAA transcription repressors and the ARF transcription factors. We have previously shown that the AFB3 auxin receptor has a specific role in coordinating primary and lateral root growth to external and internal nitrate availability (Vidal et al., 2010). In this work, we used an integrated genomics, bioinformatics and molecular genetics approach to dissect regulatory networks acting downstream AFB3 that are activated by a transient nitrate treatment in Arabidopsis roots. Our systems approach unraveled key components of the AFB3 regulatory network leading to changes in lateral root growth in response to nitrate.
Systems approaches map regulatory networks downstream of the auxin receptor AFB3 in the nitrate response of Arabidopsis thaliana roots.
Specimen part, Treatment
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