Alterations 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 SamplesA major impediment to the effective treatment of patients with PDAC (Pancreatic Ductal Adenocarcinoma) is the molecular heterogeneity of the disease, which is reflected in an equally diverse pattern of clinical responses to therapy. We developed an efficient strategy in which PDAC samples from 17 consecutively patients were obtained by EUS-FNA or surgery, their cells maintained as a primary culture and tumors as breathing tumors by xenografting in immunosuppressed mice. For these patients a clinical follow up was obtained. On the breathing tumors we studied the RNA expression profile by an Affymetrix approach. We observed a significant heterogeneity in their RNA expression profile, however, the transcriptome was able to discriminate patients with long- or short-time survival which correspond to moderately- or poorly-differentiated PDAC tumors respectively. Cells allowed us the possibility to analyze their relative sensitivity to several anticancer drugs in vitro by developing a chimiogram, like an antibiogram for microorganisms, with several anticancer drugs for obtaining an individual profile of drug sensitivity and as expected, the response was patient-dependent. Interestingly, using this approach, we also found that the transcriptome analysis could predict the sensitivity to some anticancer drugs of patients with a PDAC. In conclusion, using this approach, we found that the transcriptome analysis could predict the sensitivity to some anticancer drugs and the clinical outcome of patients with a PDAC.
Transcriptomic analysis predicts survival and sensitivity to anticancer drugs of patients with a pancreatic adenocarcinoma.
Sex, Age, Specimen part
View SamplesAnalysis of a SigX knockout mutant of Pseudomonas aeruginosa H103 strain in LB.
The absence of SigX results in impaired carbon metabolism and membrane fluidity in Pseudomonas aeruginosa.
No sample metadata fields
View SamplesA Single Cell Analysis of Myogenic Dedifferentiation Induced by Small Molecules An important direction in chemical biology is the derivation of compounds that affect cellular differentiation or its reversal. The fragmentation of multinucleate myofibers into viable mononucleates (called cellularisation) occurs during limb regeneration in urodele amphibians and the isolation of myoseverin, a tri-substituted purine that could apparently activate this pathway of myogenic dedifferentiation in mammalian cells, generated considerable interest. We have explored the mechanism and outcome of cellularisation at a single cell level, and report findings that significantly extend the previous work with myoseverin. Using a panel of compounds, including a novel triazine compound called 109 with structural similarity and comparable activity to myoseverin, we have identified microtubule disruption as critical for activation of the response. Our analysis has included the related control triazine compound 401, and the microtubule disrupting agent nocodazole. Time-lapse microscopy has enabled us to analyse the fate of identified mononucleate progeny, and directly assess the extent of dedifferentiation.
A single-cell analysis of myogenic dedifferentiation induced by small molecules.
Specimen part, Cell line, Compound, Time
View SamplesNaive spleens as well as naive and LPS-treated dendritic cells from wildtype and GPR34-/- mice were sequenced to integrate expression profiles with protein interaction networks and find functional modules that are affected by GPR34 Overall design: Expression profiles of dendritic cells and whole spleens were generated using Illumina HiSeq 2500/ Illumina HiScan
Dendritic Cells Regulate GPR34 through Mitogenic Signals and Undergo Apoptosis in Its Absence.
No sample metadata fields
View SamplesYears after the discovery that Dicer is a key enzyme in gene-silencing, the role of its helicase domain remains enigmatic. Here we show that this domain is critical for accumulation of certain endogenous small interfering RNAs (endo-siRNAs) in C. elegans. The domain is required for the production of the direct products of Dicer, or primary endo-siRNAs, and consequently, affects levels of downstream intermediates, the secondary endo-siRNAs. Consistent with the role of endo-siRNAs in silencing, their loss correlates with an increase in cognate mRNA levels. We find that the helicase domain of Dicer is not required for microRNA (miRNA) processing, or RNA interference following exposure to exogenous double-stranded RNA. Comparisons of wildtype and helicase-defective strains using deep-sequencing analyses show that the helicase domain is required by a subset of annotated endo-siRNAs, in particular, those associated with the slightly longer 26 nucleotide small RNA species containing a 5' guanosine. Overall design: We reintroduced either wildtype Dicer, or Dicer harboring a mutation (K39A) in it''s helicase domain, into dcr-1(ok247) mutant worms via transgene rescue. We then used high-throughput sequencing to compare levels of small RNAs present in each of these strains.
Dicer's helicase domain is required for accumulation of some, but not all, C. elegans endogenous siRNAs.
Cell line, Subject
View SamplesComparison of the changes in mitochondrial gene expression of cells in which extracellular growth factors and/or mitogens have been added.
Extracellular growth factors and mitogens cooperate to drive mitochondrial biogenesis.
Specimen part
View SamplesWe describe here an interrupted reprogramming strategy to generate "induced Progenitor-Like (iPL) cells" from Alveolar Epithelial Type II (AEC-II) cells. A carefully defined period of transient expression of reprogramming factors (Oct4, Sox2, Klf4 and c-Myc; OSKM) is able to rescue the limited in vitro clonogenic capacity of AEC-II cells, potentially by activation of a bipotential progenitor-like state.
Interrupted reprogramming of alveolar type II cells induces progenitor-like cells that ameliorate pulmonary fibrosis.
Specimen part
View SamplesChickens divergently selected for either high growth (HG genotype) or low growth (LG genotype) at SRA-INRA, France were used to profile abdominal adipose gene expression at 7 wk of age. The HG and LG chickens are different in various phenotypic and metabolic measurements, including growth rate, abdominal fat, plasma glycemia, insulinemia, T4, T3, triglyceride and NEFA. The HG and LG chickens are valuable as a model for biomedical and agricultural traits. Massively parallel RNA sequencing (RNA-Seq) was completed on an Illumina HiSeq 2000 System for transcription analysis of HG and LG abdominal fat. Need information on data processing, statistical analysis, and differential expression. Keywords: abdominal fat, divergently selected chickens, growth, transcriptional profiling, differentially expressed genes Overall design: Abdominal fat mRNA profiles of high growth (HG genotype) or low growth (LG genotype) chickens at 7 weeks of age were generated by deep sequencing (on an Illumina HiSeq 2000 system).
Transcriptional analysis of abdominal fat in chickens divergently selected on bodyweight at two ages reveals novel mechanisms controlling adiposity: validating visceral adipose tissue as a dynamic endocrine and metabolic organ.
Age, Specimen part, Subject
View Samples