Human myelopoiesis is an exciting biological model for cellular differentiation since it represents a plastic process where pluripotent stem cells gradually limit their differentiation potential, generating different precursor cells which finally evolve into distinct terminally differentiated cells. This study aimed at investigating the genomic expression during myeloid differentiation through a computational approach that integrates gene expression profiles with functional information and genome organization. The genomic distribution of myelopoiesis genes was investigated integrating transcriptional and functional characteristics of genes. The analysis of genomic expression during human myelopoiesis using an integrative computational approach allowed discovering important relationships between genomic position, biological function and expression patterns and highlighting chromatin domains, including genes with coordinated expression and lineage-specific functions.
Motif discovery in promoters of genes co-localized and co-expressed during myeloid cells differentiation.
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View SamplesHuman myelopoiesis is an exciting biological model for cellular differentiation since it represents a plastic process where pluripotent stem cells gradually limit their differentiation potential, generating different precursor cells which finally evolve into distinct terminally differentiated cells. This study aimed at investigating the genomic expression during myeloid differentiation through a computational approach that integrates gene expression profiles with functional information and genome organization. The genomic distribution of myelopoiesis genes was investigated integrating transcriptional and functional characteristics of genes. The analysis of genomic expression during human myelopoiesis using an integrative computational approach allowed discovering important relationships between genomic position, biological function and expression patterns and highlighting chromatin domains, including genes with coordinated expression and lineage-specific functions.
Motif discovery in promoters of genes co-localized and co-expressed during myeloid cells differentiation.
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View SamplesSeveral reports indicate that mesalazine (5-aminosalicylic acid or 5-ASA) is a promising candidate for the chemoprevention of Colo-Rectal Cancer (CRC) due to its ability to reach the purpose, yet avoiding at the same time the side effects that are usually determined by prolonged administrations of Non Steroidal Anti-Inflammatory Drugs. This activity of 5-ASA is probably the consequence of a number of effects determined on colon cancer cells and consisting of reduced proliferation, increased apoptosis and activation of cell cycle checkpoints. A recent observation has suggested that these effects could be mediated by the capacity of 5-ASA to interfere with the nuclear translocation of beta-catenin, in turn responsible for the inhibition of its transcription activity. The aim of our study was to better characterize the molecular mechanism by which 5-ASA inhibits the beta-catenin signaling pathway. To address this issue we assessed, by means of the Affymetrix microarray methodology, the transcriptome changes determined on Caco2 cells by a 96 h treatment with 20 mM mesalazine.
Mesalazine inhibits the beta-catenin signalling pathway acting through the upregulation of mu-protocadherin gene in colo-rectal cancer cells.
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View SamplesChIP-on-chip has emerged as a powerful tool to dissect the complex network of regulatory interactions between transcription factors and their targets. However, most ChIP-on-chip analysis methods use conservative approaches aimed to minimize false-positive transcription factor targets. We present a model with improved sensitivity in detecting binding events from ChIP-on-chip data. Its application to human T-cells, followed by extensive biochemical validation, reveals that three transcription factor oncogenes, NOTCH1, MYC, and HES1, bind to several thousands target gene promoters, up to an order of magnitude increase over conventional analysis methods. Gene expression profiling upon NOTCH1 inhibition shows broad-scale functional regulation across the entire range of predicted target genes, establishing a closer link between occupancy and regulation. Finally, the increased sensitivity reveals a combinatorial regulatory program in which MYC co-binds to virtually all NOTCH1-bound promoters. Overall, these results suggest an unappreciated complexity of transcriptional regulatory networks and highlight the fundamental importance of genome-scale analysis to represent transcriptional programs.
ChIP-on-chip significance analysis reveals large-scale binding and regulation by human transcription factor oncogenes.
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View SamplesReprogramming human somatic cells into induced pluripotent stem cells (iPSC) has been suspected of causing de novo copy number variations (CNVs). To explore this issue, we performed a whole-genome and transcriptome analysis of 20 human iPSC lines derived from primary skin fibroblasts of 7 individuals using next-generation sequencing. We find that, on average, an iPSC line manifests two CNVs not apparent in the fibroblasts from which the iPSC was derived. Using qPCR, PCR, and digital droplet PCR (ddPCR) to amplify across the CNVs'' breakpoints, we show that at least 50% of those CNVs are present as low frequency somatic genomic variants in parental fibroblasts and are manifested in iPSC colonies due to their clonal origin. Hence, reprogramming does not necessarily lead to de novo CNVs in iPSC, since most of line-manifested CNVs reflect somatic mosaicism in the human skin. Moreover, our findings demonstrate that clonal expansion, and iPSC lines in particular, can be used as a discovery tool to reliably detect low frequency CNVs in the tissue of origin. Overall, we estimate that approximately 30% of the fibroblast cells have somatic CNVs, suggesting widespread somatic mosaicism in the human body. Our study paves the way to understanding the fundamental question of the extent to which cells of the human body normally acquire structural alterations in their DNA post-zygotically. Overall design: We have generated and characterized hiPSC lines derived from skin fibroblasts collected from seven members of two families, which were competent to be differentiated into neuronal progenitors and neurons
Somatic copy number mosaicism in human skin revealed by induced pluripotent stem cells.
Specimen part, Subject
View SamplesWe identify perhexiline, a small molecule inhibitor of mitochondrial carnitine palmitoyltransferase-1, as a HES1-signature antagonist drug with robust antileukemic activity against NOTCH1 induced leukemias in vitro and in vivo. Overall design: RNA-Seq from CUTLL1 cell lines treated with Perhexiline or vehicle for 3 days
Therapeutic targeting of HES1 transcriptional programs in T-ALL.
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View SamplesAlthough a considerable number of reports indicate an involvement of the Hox-A10 gene in the molecular control of hematopoiesis, the conclusions of such studies are quite controversial since they support, in some cases, a role in the stimulation of stem cell self-renewal and myeloid progenitor expansion while, in others, implicate this transcription factor in the induction of monocyte - macrophage differentiation. To clarify this issue we analyzed the biological effects and the transcriptome changes determined in human primary CD34+ hematopoietic progenitors by retroviral transduction of a full length Hox-A10 cDNA. The results obtained clearly indicated that this homeogene is an inducer of monocyte differentiation, at least partly acting through the up-regulation of MafB gene, recently identified as master regulator of such maturation pathway. By using a combined approach based on computational analysis, EMSA experiments and luciferase assays, we were able to demonstrate the presence of a Hox-A10 binding site in the promoter region of the MafB gene, which suggested the likely molecular mechanism underlying the observed effect. Interestingly, stimulation of the same cells with the Vitamin D3 monocyte differentiation inducer resulted in a clear increase of Hox-A10 and MafB transcripts, indicating the existence of a precise transactivation cascade involving VDR, Hox-A10 and MafB transcription factors. Altogether these data allow to conclude that the Vitamin D3 / Hox-A10 pathway supports MafB function during the induction of monocyte differentiation.
The vitamin D3/Hox-A10 pathway supports MafB function during the monocyte differentiation of human CD34+ hemopoietic progenitors.
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View SamplesCutaneous squamous cell carcinoma (cSCC) is the second most common malignancy in humans and approximately 5% metastasize, usually to regional lymph nodes. Epigenetic regulation of gene expression may allow tumoral cells to acquire new functions in order to escape from the primary tumor. The aim of this study was to investigate the expression and function of proteins of the Polycomb family of epigenetic regulators in the metastatic process of cSCC. A higher expression of RING1B and EZH2 was detected by immunohistochemistry in a series of primary cSCC tumors that metastasized (MSCC) when compared to non metastasizing cSCC (non MSCC). Stable downregulation of RING1B and EZH2 in cSCC cells results in enhanced expression of inflammatory cytokines and activation of the NFB signaling pathway. Accordingly, non MSCC display higher levels of membranous pS176 IKK and their stroma is enriched in neutrophils and eosinophils when compared to MSCC. In vitro, hematopoietic cells exhibit a substantial migratory response to supernatants from Polycomb depleted cSCC cells. Altogether these data indicate that RING1B and EZH2 repress the innate inflammatory cSCC function and impair tumor immunosurveillance and suggest that patients with high risk cSCC could benefit from clinical therapies addressed to harness the immune response.
The Polycomb proteins RING1B and EZH2 repress the tumoral pro-inflammatory function in metastasizing primary cutaneous squamous cell carcinoma.
Specimen part, Cell line
View SamplesThe TLX1 and TLX3 transcription factor oncogenes play an important role in the pathogenesis of T-cell acute lymphoblastic leukemia (T-ALL)1,2. Here we used reverse engineering of global transcriptional networks to decipher the oncogenic regulatory circuit controlled by TLX1 and TLX3. This Systems Biology analysis defined TLX1 and TLX3 as master regulators of an oncogenic transcriptional circuit governing T-ALL. Notably, network structure analysis of this hierarchical network identified RUNX1 as an important mediator of TLX1 and TLX3 induced T-ALL, and predicted a tumor suppressor role for RUNX1 in T-cell transformation. Consistent with these results, we identified recurrent somatic loss of function mutations in RUNX1 in human T-ALL. Overall, these results place TLX1 and TLX3 atop of an oncogenic transcriptional network controlling leukemia development, demonstrate power of network analysis to identify key elements in the regulatory circuits governing human cancer and identify RUNX1 as a tumor suppressor gene in T-ALL.
Disregulated expression of the transcription factor ThPOK during T-cell development leads to high incidence of T-cell lymphomas.
Specimen part, Cell line
View SamplesTransgenic expression of key transcritpion factors inducing T-cell leukemias in mice.
Disregulated expression of the transcription factor ThPOK during T-cell development leads to high incidence of T-cell lymphomas.
Specimen part
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