The exon junction complex (EJC) is a highly conserved ribonucleoprotein complex which binds RNAs at a late stage of the splicing reaction and remains associated following export to the cytoplasm. This complex is involved in several cellular post-transcriptional processes including mRNA localization, translation and degradation. The EJC plays an additional role in the splicing of a subset of genes in Drosophila and in human cells but the underlying mechanism remains to be elucidated. Here, we have found a novel function for the EJC and its splicing subunit RnpS1 in preventing transposon accumulation in both Drosophila germline and surrounding follicular cells. This function is mediated specifically through the control of the splicing of the piwi transcript. In absence of RnpS1 one of the piwi intron is retained. This intron contains a weak 5’ splice site as well as degenerate transposon fragments, reminiscent of heterochromatic introns. In addition, we identified a small A/T rich region, which alters its polypyrimidine tract (PPT) and confers the RnpS1’s dependency. Finally, we showed that the removal of this intron by RnpS1 requires the initial splicing of the flanking introns, suggesting a model in which the EJC facilitates the splicing of challenging introns following its initial deposition to adjacent exon junctions. Overall design: In total there are 4 different conditions. Comparisons were made between piwi mutant vs control piwi and rnps1 KD vs controls RnpS1
The exon junction complex controls transposable element activity by ensuring faithful splicing of the piwi transcript.
Specimen part, Subject
View SamplesGlucocorticoids (GCs) are commonly used to treat patients suffering from lymphoid malignancies i.e. leukemia and multiple myeloma. Although GCs are known to be strong inducers of apoptosis in lymphoid cells, the molecular determinants of GC therapy resistance are poorly understood. Although GC treatment triggers important changes in gene expression, few studies have addressed the regulatory role of small regulatory microRNAs (miRNAs) in GC therapy response. Only recently, aberrant microRNA expression has been linked to the development of haematological malignancies and microRNAs have become master regulators of drug resistance. We identified GC inducible mRNA and microRNA transcription profiles in GC sensitive MM1S as compared to GC resistant MM1R cells. Transcriptome analysis revealed that GCs regulate multiple genes involved in cell cycle control, cell organization and cell death in MM1S, which remain unaffected in MM1R cells. Correspondingly, GCs selectively trigger cell death in MM1S but not in MM1R. Out of 32 microRNAs responsive to GC in MM1S cells but not in MM1R cells, mir-150 was identified as the most persistent GC responsive microRNA. Furthermore, Ingenuity Pathways Analysis (IPA) revealed that ectopic transfection of a synthetic mir-150 mimics GC therapy response in MM1S cells, associated with selective changes in mRNA levels of typical GR transactivated and transrepressed target genes. Although mir-150 largely mirrors GC responsive changes in gene expression of the transcription factor Myb, GR chaperone FKBP5, cell cycle modulator proteins (IL23A, SKP2, CDKN1A), chemokine signaling proteins (CXCR4, CX3CR1, CCL3) and mTOR/UPR stress related proteins (DDIT4, TXNIP), we also observed mir-150 selective effects on transcription factors (NR3C2 (MR), Myb, Fos, Jun, C/EBP-beta, IRF4, NFE2L1, ATF3, ATF4,), chaperone molecules HSPA8, HSP90AB1), the sodium channel SCNN1G and UPR stress proteins (TRIB3, DDIT3). Remarkably, mir-150 overexpression was not able to overcome GC therapy resistance, since we could not detect GC like effects of mir-150 in GR (NR3C1) deficient MM1R cells. Altogether GC-inducible mir-150 adds a novel complex layer of regulation for fine tuning GC specific therapeutic responses in multiple myeloma.
Ectopic microRNA-150-5p transcription sensitizes glucocorticoid therapy response in MM1S multiple myeloma cells but fails to overcome hormone therapy resistance in MM1R cells.
Cell line, Treatment
View SamplesTargeting immunomodulatory pathways has ushered a new era in lung cancer therapy. Further progress requires deeper insights into the nature and dynamics of immune cells in the lung cancer micro-environment. Dendritic cells (DCs) represent a heterogenous and highly plastic immune cell system with a central role in controlling immune responses. The intratumoral infiltration and activation status of DCs emerge as clinically relevant parameters in lung cancer. In this study we used an orthotopic preclinical model of lung cancer to interrogate the transcriptome of lung tumor-infiltrating DCs and extract novel biologically and clinically relevant information. Lung tumor-infiltrating leukocytes expressing generic DC markers were found to predominantly consist of CD11b+ cells which, compared to peritumoral lung DC counterparts, strongly over-express the T cell inhibitory molecule PD-L1 and acquire classic markers of tumor-supporting macrophages (TAM) on their surface. Transcriptome analysis of these CD11b+ tumor-infiltrating DCs (TIDCs) indicates impaired anti-tumoral immunogenicity, confirms the skewing towards TAM-related features, and indicates exposure to a hypoxic environment. In paralled, TIDCs display a specific micro-RNA signature dominated by the prototypical lung cancer oncomir miR-31. Hypoxia was found to drive intrinsic miR-31 expression in CD11b+DCs. Conditioned medium of mir-31-overexpressing CD11b+DCs induces pro-invasive lung cancer cell shape changes and is enriched with the pro-metastatic factors S100A8 and S100A9. Finally, analysis of TCGA datasets reveals that the TIDC-associated miRNA signature has a negative prognostic impact in non-small cell lung cancer. Together, these data suggest a novel mechanism through which lung cancer co-opts the plasticity of the DC system to support tumoral progression. Targeting immunomodulatory pathways has ushered a new era in lung cancer therapy. Further progress requires deeper insights into the nature and dynamics of immune cells in the lung cancer micro-environment. Dendritic cells (DCs) represent a heterogenous and highly plastic immune cell system with a central role in controlling immune responses. The intratumoral infiltration and activation status of DCs emerge as clinically relevant parameters in lung cancer. In this study we used an orthotopic preclinical model of lung cancer to interrogate the transcriptome of lung tumor-infiltrating DCs and extract novel biologically and clinically relevant information. Lung tumor-infiltrating leukocytes expressing generic DC markers were found to predominantly consist of CD11b+ cells which, compared to peritumoral lung DC counterparts, strongly over-express the T cell inhibitory molecule PD-L1 and acquire classic markers of tumor-supporting macrophages (TAM) on their surface. Transcriptome analysis of these CD11b+ tumor-infiltrating DCs (TIDCs) indicates impaired anti-tumoral immunogenicity, confirms the skewing towards TAM-related features, and indicates exposure to a hypoxic environment. In paralled, TIDCs display a specific micro-RNA signature dominated by the prototypical lung cancer oncomir miR-31. Hypoxia was found to drive intrinsic miR-31 expression in CD11b+DCs. Conditioned medium of mir-31-overexpressing CD11b+DCs induces pro-invasive lung cancer cell shape changes and is enriched with the pro-metastatic factors S100A8 and S100A9. Finally, analysis of TCGA datasets reveals that the TIDC-associated miRNA signature has a negative prognostic impact in non-small cell lung cancer. Together, these data suggest a novel mechanism through which lung cancer co-opts the plasticity of the DC system to support tumoral progression.
The transcriptome of lung tumor-infiltrating dendritic cells reveals a tumor-supporting phenotype and a microRNA signature with negative impact on clinical outcome.
Specimen part
View SamplesLong intergenic non-coding RNAs (lincRNAs) are emerging as integral components of signaling pathways in various cancer types. In neuroblastoma, only a handful of lincRNAs are known as upstream regulators or downstream effectors of oncogenes. Here, we exploit RNA sequencing data of primary neuroblastoma tumors, neuroblast precursor cells, neuroblastoma cell lines and various cellular perturbation model systems to define the neuroblastoma lincRNome and map lincRNAs up- and downstream of neuroblastoma driver genes MYCN, ALK and PHOX2B. Each of these driver genes controls the expression of a particular subset of lincRNAs, several of which are associated with poor survival and are differentially expressed in neuroblastoma tumors compared to neuroblasts. By integrating RNA sequencing data from both primary tumor tissue and cancer cell lines, we demonstrate that several of these lincRNAs are expressed in stromal cells. Deconvolution of primary tumor gene expression data revealed a strong association between stromal cell composition and driver gene status, resulting in differential expression of these lincRNAs. We also explored lincRNAs that putatively act upstream of neuroblastoma driver genes, either as presumed modulators of driver gene activity, or as modulators of effectors regulating driver gene expression. This analysis revealed strong associations between the neuroblastoma lincRNAs MIAT and MEG3 and MYCN and PHOX2B activity or expression. Together, our results provide a comprehensive catalogue of the neuroblastoma lincRNome, highlighting lincRNAs up- and downstream of key neuroblastoma driver genes. This catalogue forms a solid basis for further functional validation of candidate neuroblastoma lincRNAs. Overall design: CLB-GA was transduced with control or inducible shPHOX2B. The cells were treated with doxycycline for 5 days.
Integrative analysis identifies lincRNAs up- and downstream of neuroblastoma driver genes.
Cell line, Treatment, Subject
View SamplesThe miR-17-92 microRNA cluster is often activated in cancer cells, but the identity of its targets remains largely elusive. Here we examined the effects of activation of the entire miR-17-92 cluster on global protein expression in neuroblastoma cells.
The miR-17-92 microRNA cluster regulates multiple components of the TGF-β pathway in neuroblastoma.
Specimen part
View SamplesGenetic studies in T-cell acute lymphoblastic leukemia have uncovered a remarkable complexity of oncogenic and loss-of-function mutations. Amongst this plethora of genetic changes, NOTCH1 activating mutations stand out as the most frequently occurring genetic defect, identified in more than 50% of T-cell acute lymphoblastic leukemias, supporting an essential driver role for this gene in T-cell acute lymphoblastic leukemia oncogenesis. In this study, we aimed to establish a comprehensive compendium of the long non-coding RNA transcriptome under control of Notch signaling. For this purpose, we measured the transcriptional response of all protein coding genes and long non-coding RNAs upon pharmacological Notch inhibition in the human T-cell acute lymphoblastic leukemia cell line CUTLL1 using RNA-sequencing. Similar Notch dependent profiles were established for normal human CD34+ thymic T-cell progenitors exposed to Notch signaling activity in vivo. In addition, we generated long non-coding RNA expression profiles (array data) from GSI treated T-ALL cell lines, ex vivo isolated Notch active CD34+ and Notch inactive CD4+CD8+ thymocytes and from a primary cohort of 15 T-cell acute lymphoblastic leukemia patients with known NOTCH1 mutation status. Integration of these expression datasets with publically available Notch1 ChIP-sequencing data resulted in the identification of long non-coding RNAs directly regulated by Notch activity in normal and malignant T-cell context. Given the central role of Notch in T-cell acute lymphoblastic leukemia oncogenesis, these data pave the way towards development of novel therapeutic strategies that target hyperactive Notch1 signaling in human T-cell acute lymphoblastic leukemia. Overall design: CUTLL1 cell lines were treated with Compound E (GSI) or DMSO (solvent control). Cells were collected 12 h and 48 h after treatment. This was performed for 3 replicates. RNA-sequencing was performed on these samples.
The Notch driven long non-coding RNA repertoire in T-cell acute lymphoblastic leukemia.
No sample metadata fields
View SamplesTranslation initiation factor eIF4E is overexpressed early in breast cancers in association with disease progression and reduced survival. Much remains to be understood regarding the role of eIF4E in human cancer. Using immortalized human breast epithelial cells, we report that elevated expression of elF4E translationally activates the TGF pathway, promoting cell invasion, loss of cell polarity, increased cell survival and other hallmarks of early neoplasia. Overexpression of eIF4E is shown to facilitate selective translation of integrin 1 mRNA, which drives the translationally controlled assembly of a TGF receptor signaling complex containing 31 integrins, -catenin, TGF receptor I, E-cadherin and phosphorylated Smads2/3. This receptor complex acutely sensitizes non-malignant breast epithelial cells to activation by typically sub-stimulatory levels of activated TGF. TGF can promote cellular differentiation or invasion and transformation. As a translational coactivator of TGF, eIF4E confers selective mRNA translation, reprogramming non-malignant cells to an invasive phenotype by reducing the set-point for stimulation by activated TGF. Overexpression of eIF4E may be a pro-invasive facilitator of TGF activity.
Eukaryotic Translation Initiation Factor 4E Is a Feed-Forward Translational Coactivator of Transforming Growth Factor β Early Protransforming Events in Breast Epithelial Cells.
Sex, Specimen part, Cell line
View SamplesNeuroblastoma is an embryonal tumor arising from the neural crest. It can be mimicked in mice by neural crest-specific overepxression of oncogenes such as MYCN or mutated ALK.
Targeted expression of mutated ALK induces neuroblastoma in transgenic mice.
Specimen part
View SamplesThis dataset contains gene expression data from the NRC series (Neuroblastoma Research Consortium) for a total of 283 primary neuroblastoma tumors. All tumor samples are fully annotated including patient age at diagnosis, overall and progresison free survival and MYCN amplification status, enabling subgroup analysis, survival analysis and gene expression network analysis.
Cross-Cohort Analysis Identifies a TEAD4-MYCN Positive Feedback Loop as the Core Regulatory Element of High-Risk Neuroblastoma.
No sample metadata fields
View SamplesNetwork-based analysis of neuroblastoma samples from two large cohorts identified master regulator proteins controlling the transcriptional state of three high-risk molecular subtypes. In particular, a TEAD4-MYCN positive feedback loop emerged as the core regulatory motif of a small protein module presiding over implementation and stability of the subtype associated with MYCN amplification. Specifically, MYCN transcriptionally activates TEAD4, which in turn activates MYCN both transcriptionally and post-translationally. The resulting MYCN-TEAD4 positive feedback loop plays a critical role in maintaining aberrant activity of a 10-protein regulatory module that causally regulates the transcriptional state of this subtype. Consistently, loss of TEAD4 activity induces core module activity collapse and abrogates neuroblastoma cell viability in vitro and in vivo, thus suggesting novel therapeutic strategies for this important childhood cancer. Overall design: Study of the transcriptional control by TEAD4 and MYCN positive feedback loop using RNA-seq profiles of TEAD4, WWTR1 and MYCN shRNA knockdowns in neuroblastoma BE2 cells. ChIP-Seq analysis using TEAD4 antibody in BE2 cells.
Cross-Cohort Analysis Identifies a TEAD4-MYCN Positive Feedback Loop as the Core Regulatory Element of High-Risk Neuroblastoma.
No sample metadata fields
View Samples