Expression of the SS18/SYT-SSX fusion protein is believed to underlie the pathogenesis of synovial sarcoma (SS). Recent evidence suggests that deregulation of the Wnt pathway may play an important role in SS but the mechanisms whereby SS18-SSX might affect Wnt signaling remain to be elucidated. Here, we show that SS18/SSX tightly regulates the elevated expression of the key Wnt target AXIN2 in primary SS. SS18-SSX is shown to interact with TCF/LEF, TLE and HDAC but not -catenin in vivo and to induce Wnt target gene expression by forming a complex containing promoter-bound TCF/LEF and HDAC but lacking -catenin. Our observations provide a tumor-specific mechanistic basis for Wnt target gene induction in SS that can occur in the absence of Wnt ligand stimulation.
The fusion protein SS18-SSX1 employs core Wnt pathway transcription factors to induce a partial Wnt signature in synovial sarcoma.
Cell line
View SamplesLung cancer is a highly malignant tumor and the majority of cancer-related deaths are due to metastasis. The tumor microenvironment (TME) plays a fundamental role in the metastatic spread of tumor cells. Among other stromal cells, mesenchymal stem cells (MSCs) are known to be present within the TME and to be involved in cancer progression. However the majority of previous studies have been performed on bone marrow-derived MSCs. To investigate the role of the TME on the pulmonary MSC phenotype, we compared the expression profile of paired MSCs isolated from lung tumor (T-) and normal adjacent tissues (N-) from lung carcinoma patients.
Reciprocal modulation of mesenchymal stem cells and tumor cells promotes lung cancer metastasis.
Specimen part, Disease stage, Subject
View SamplesBackground
STOX1 overexpression in choriocarcinoma cells mimics transcriptional alterations observed in preeclamptic placentas.
No sample metadata fields
View SamplesThe exposure to and contamination by Persistent Organic Pollutants (POPs), which include pesticides used worldwide and polyaromatic hydrocarbons, is detrimental to human health and diverse ecosystems. Although most mechanistic studies have focused on single compounds, living organisms are exposed to multiple environmental xenobiotics, simultaneously, throughout their lives. The experimental evidence useful for assessing the effects of exposure to pollutant mixtures is scarce. We investigated the effects of exposure to a combination of two POPs, which employ different xenosensors, on global gene expression in a human hepatocyte cell model, HepaRG.
Two persistent organic pollutants which act through different xenosensors (alpha-endosulfan and 2,3,7,8 tetrachlorodibenzo-p-dioxin) interact in a mixture and downregulate multiple genes involved in human hepatocyte lipid and glucose metabolism.
Specimen part
View SamplesX-chromosome inactivation (XCI) provides a dosage compensation mechanism where, in each female cell, one of the two X chromosomes is randomly silenced. However, some genes on the inactive X chromosome and outside the pseudoautosomal regions escape from XCI and are expressed from both alleles (escapees). We investigated XCI at single-cell resolution combining deep single cellRNA sequencing with whole-genome sequencing to examine allelic-specific expression in 935 primary fibroblast and 48 lymphoblastoid single cells from five female individuals. In this framework we integrated an original method to identify and exclude doublets of cells. In fibroblast cells, we have identified 55 genes as escapees including five novel escapee genes. Moreover, we observed that all genes exhibit a variable propensity to escape XCI in each cell and cell type and that each cell displays a distinct expression profile of the escapee genes. A metric, the Inactivation Score—defined as the mean of the allelic expression profiles of the escapees per cell—enables us to discover a heterogeneous and continuous degree of cellular XCI with extremes represented by “inactive” cells, i.e., cells exclusively expressing the escaping genes from the active X chromosome and “escaping” cells expressing the escapees from both alleles. We found that this effect is associated with cell-cycle phases and, independently, with the XIST expression level, which is higher in the quiescent phase (G0). Single-cell allele-specific expression is a powerful tool to identify novel escapees in different tissues and provide evidence of an unexpected cellular heterogeneity of XCI. Overall design: Single-cell RNA seq study on 935 human fibroblasts and 48 lymphoblastoid cells from 5 female individuals, in order to investigate the X chromosome nactivation mechanism on a single cell level and to identify escapee genes
Single cell transcriptome in aneuploidies reveals mechanisms of gene dosage imbalance.
Specimen part, Subject
View SamplesThe intestinal epithelium is continuously renewed by a pool of intestinal stem cells expressing Lgr5. We show that deletion of the key autophagy gene Atg7 affects the survival of Lgr5+ intestinal stem cells. Mechanistically, this involves defective DNA repair, oxidative stress, and altered interactions with the microbiota. This study highlights the importance of autophagy in maintaining the integrity of intestinal stem cells.
Essential role for autophagy protein ATG7 in the maintenance of intestinal stem cell integrity.
Specimen part
View SamplesDown syndrome (trisomy 21) is the most common viable chromosomal disorder with intellectual impairment and several other developmental abnormalities. Here, we report the generation and characterization of induced pluripotent stem cells (iPSCs) derived from monozygotic twins discordant for trisomy 21 in order to eliminate the effects of the variability of genomic background. The alterations observed by genetic analysis at the iPSC level and at first approximation in early development illustrate the developmental disease transcriptional signature of Down syndrome. Moreover, we observed an abnormal neural differentiation of Down syndrome iPSCs in vivo when formed teratoma in NOD-SCID mice, and in vitro when differentiated into neuroprogenitors and neurons. These defects were associated with changes in the architecture and density of neurons, astroglial and oligodendroglial cells together with misexpression of genes involved in neurogenesis, lineage specification and differentiation. Furthermore, we provide novel evidence that dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1A (DYRK1A) on chromosome 21 likely contribute to these defects. Importantly, we found that targeting DYRK1A pharmacologically or by shRNA results in a considerable correction of these defects. Overall design: mRNA-seq profiling of iPS cells (4 euploid and 3 trisomy 21) derived from fibroblasts of monozygotic twins discordant for trisomy 21
Modelling and rescuing neurodevelopmental defect of Down syndrome using induced pluripotent stem cells from monozygotic twins discordant for trisomy 21.
No sample metadata fields
View SamplesDown syndrome (DS) results from trisomy of chromosome 21 (HSA21). Some DS phenotypes may be directly or indirectly related to the increased expression of specific HSA21 genes, in particular those encoding transcription factors. The HSA21 encoded Single-minded 2 (SIM2) transcription factor has key neurological functions and is a good candidate to be involved in the cognitive impairment of DS. ChIP-sequencing was used to map SIM2 binding in mouse embryonic stem cells and has revealed 1229 high-confidence SIM2-binding sites. Analysis of the SIM2 target genes confirmed the importance of SIM2 in developmental and neuronal processes and indicated that SIM2 may be a master transcription regulator. Indeed, SIM2 DNA binding sites share sequence specificity and overlapping domains of occupancy with master transcription factors such as SOX2, OCT4, NANOG or KLF4. The association between SIM2 and these pioneer factors is supported by the finding that SIM2 can be co-immunoprecipitated with SOX2, OCT4, NANOG or KLF4. Furthermore, the binding of SIM2 marks a particular sub-category of enhancers known as super-enhancers. These regions are characterized by typical DNA modifications and Mediator co-occupancy (MED1 and MED12). Altogether, we provide evidence that SIM2 binds a specific set of enhancer elements thus explaining how SIM2 can regulate its gene network in DS neuronal features. Overall design: RNA-Seq analysis in Sim2 expressing cells (3 replicates A6, B8, C4) and EB3 control cells (3 replicates)
HSA21 Single-Minded 2 (Sim2) Binding Sites Co-Localize with Super-Enhancers and Pioneer Transcription Factors in Pluripotent Mouse ES Cells.
No sample metadata fields
View SamplesIn several developmental lineages, an increase in expression of the MYC proto-oncogene drives the transition from quiescent stem cells to transit amplifying cells. The mechanism by which MYC restricts self-renewal of adult stem cells is unknown. Here, we show that MYC activates a stereotypic transcriptional program of genes involved in protein translation and mitochondrial biogenesis in mammary epithelial cells and indirectly inhibits the YAP/TAZ co-activators that are essential for mammary stem cell self-renewal. We identify a phospholipase of the mitochondrial outer membrane, PLD6, as the mediator of MYC activity. PLD6 mediates a change in the mitochondrial fusion/fission balance that promotes nuclear export of YAP/TAZ in a LATS- and RHO-independent manner. Mouse models and human pathological data confirm that MYC suppresses YAP/TAZ activity in mammary tumors. PLD6 is also required for glutaminolysis, arguing that MYC-dependent changes in mitochondrial dynamics balance cellular energy metabolism with the self-renewal potential of adult stem cells. Overall design: RNA-Seq Experiments in 2 different primary breast epithelial cell lines (HMLE, which were sorted according to CD44/CD24 surface markers & unsorted IMEC). Both cell lines expressed a doxycycline-inducible version of MYC. For the HMLE cell line DGE analysis was performed for the uninduced (EtOH) situation, comparing CD44high vs CD44 low and for the induced situation Dox vs. EtOH for the CD44high population. For the IMEC cell line DGE was performed by comparing Dox-treated populations expressing either Dox-inducible MYC or a vector control which allows to filter out potential effects due to doxycycline treatment.
A MYC-Driven Change in Mitochondrial Dynamics Limits YAP/TAZ Function in Mammary Epithelial Cells and Breast Cancer.
No sample metadata fields
View SamplesM9 glucose minimum media were analyzed for RNA expression.
Codon influence on protein expression in E. coli correlates with mRNA levels.
No sample metadata fields
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