Assessing the carcinogenic potential of drug candidates is a costly procedure which requires the life-long treatment of rodents at different dose levels. A promising approach, which may to a certain degree reduce the need for animal studies in the future is toxicogenomics. The idea is to employ microarray platforms for the genome-wide expression profiling of compounds, which may facilitate the discovery of biomarker genes and provide insights in molecular mechanisms.
A toxicogenomic approach for the prediction of murine hepatocarcinogenesis using ensemble feature selection.
Sex, Specimen part, Treatment, Time
View SamplesNeurofibromatosis type 1 (NF1) is a multi-system disease caused by mutations in the NF1 gene encoding a Ras-GAP protein, neurofibromin, which negatively regulates Ras signalling. Besides neuroectodermal malformations and tumours, the skeletal system is often affected (e.g. scoliosis and long bone dysplasia), demonstrating the importance of neurofibromin for development and maintenance of the musculoskeletal system. Here we focus on the role of neurofibromin in skeletal muscle development. Nf1 gene inactivation in the early limb bud mesenchyme using Prx1-cre (Nf1Prx1) resulted in muscle dystrophy characterised by fibrosis, reduced number of muscle fibres, and reduced muscle force. To gain insight into the molecular changes of the observed muscle dystrophy and fibrosis and to compare these with other known muscle dystrophies, we performed transcriptional profiling of the entire triceps muscles of threemonth-old wild type (wt) and mutant animals using Affymetrix high-density microrrays.
Neurofibromin (Nf1) is required for skeletal muscle development.
Age, Specimen part
View SamplesBreast cancer is a heterogeneous disease for which prognosis and treatment strategies are largely governed by the receptor status (estrogen, progesterone and Her2-neu) of the tumor cells. Gene expression profiling of whole breast tumors further stratifies breast cancer into several molecular subtypes which also co-segregate with the receptor status of the tumor cells. We postulated that cancer associated fibroblasts (CAFs) within the tumor stroma may exhibit subtype specific gene expression profiles and thus contribute to the biology of the disease in a subtype specific manner. Several studies have reported gene expression profile differences between CAFs and normal breast fibroblasts but in none of these studies were the results stratified based on tumor subtypes. To address whether gene expression in breast cancer associated fibroblasts varies between breast cancer subtypes, we compared the gene expression profiles of early passage primary CAFs isolated from twenty human breast cancer samples representing three main subtypes; seven ER+, seven triple negative (TNBC) and six Her2+. We observed significant expression differences between CAFs derived from Her2+ breast cancer and CAFs from TNBC and ER+ cancers, particularly in pathways associated with cytoskeleton and integrin signaling. In the case of Her2+ breast cancer, the signaling pathways found to be selectively up regulated in CAFs may contribute to the more invasive properties and unfavorable prognosis of Her2+ breast cancer. These data demonstrate that in addition to the distinct molecular profiles that characterize the neoplastic cells, CAF gene expression is also differentially regulated in distinct subtypes of breast cancer.
Human breast cancer associated fibroblasts exhibit subtype specific gene expression profiles.
Specimen part, Subject
View SamplesNCoR and SMRT are two paralogous vertebrate proteins that function as corepressors with unliganded nuclear receptors. Although C. elegans has a large number of nuclear receptors, orthologues of the corepressors NCoR and SMRT have not unambiguously been identified in Drosophila or C. elegans. Here, we identify GEI-8 as the closest homologue of NCoR and SMRT in C. elegans and demonstrate that GEI-8 is expressed as at least two isoforms throughout development in multiple tissues, including neurons, muscle and intestinal cells. We demonstrate that a homozygous deletion within the gei-8 coding region, which is predicted to encode a truncated protein lacking the predicted NR domain, results in severe mutant phenotypes with developmental defects, slow movement and growth, arrested gonadogenesis and defects in cholinergic neurotransmission. Whole genome expression analysis by microarrays identified sets of de-regulated genes consistent with both the observed mutant phenotypes and a role of GEI-8 in regulating transcription. Interestingly, the upregulated transcripts included a predicted mitochondrial sulfide:quinine reductase encoded by Y9C9A.16. This locus also contains non-coding, 21-U RNAs of the piRNA. Inhibition of the expression of the region coding for 21-U RNAs leads to irregular gonadogenesis in the homozygous gei-8 mutants, but not in an otherwise wild-type background, suggesting that GEI-8 may function in concert with the 21-U RNAs to regulate gonadogenesis. Our results confirm that GEI-8 is the orthologue of the vertebrate NCoR/SMRT corepressors and demonstrate important roles for this putative transcriptional corepressor in development and neuronal function.
GEI-8, a homologue of vertebrate nuclear receptor corepressor NCoR/SMRT, regulates gonad development and neuronal functions in Caenorhabditis elegans.
No sample metadata fields
View SamplesCombinatorial actions of relatively few transcription factors control hematopoietic differentiation. To investigate this process in erythro-megakaryopoiesis, we correlated the genome-wide chromatin occupancy signatures of four master hematopoietic transcription factors (GATA1, GATA2, TAL1, and FLI1) and three diagnostic histone modification marks with the gene expression changes that occur during development of primary cultured megakaryocytes (MEG) and primary erythroblasts (ERY) from murine fetal liver hematopoietic stem/progenitor cells. We identified a robust, genome-wide mechanism of MEG-specific lineage priming by a previously described stem/progenitor cell-expressed transcription factor heptad (GATA2, LYL1, TAL1, FLI1, ERG, RUNX1, LMO2) binding to MEG-associated cis-regulatory modules (CRMs) in multipotential progenitors. This is followed by genome-wide GATA factor switching that mediates further induction of MEG-specific genes following lineage commitment. Interaction between GATA and ETS factors appears to be a key determinant of these processes. In contrast, ERY-specific lineage priming is biased toward GATA2-independent mechanisms. In addition to its role in MEG lineage priming, GATA2 plays an extensive role in late megakaryopoiesis as a transcriptional repressor at loci defined by a specific DNA signature. Our findings reveal important new insights into how ERY and MEG lineages arise from a common bipotential progenitor via overlapping and divergent functions of shared hematopoietic transcription factors.
Divergent functions of hematopoietic transcription factors in lineage priming and differentiation during erythro-megakaryopoiesis.
Specimen part
View SamplesCombinatorial actions of relatively few transcription factors control hematopoietic differentiation. To investigate this process in erythro-megakaryopoiesis, we correlated the genome-wide chromatin occupancy signatures of four master hematopoietic transcription factors (GATA1, GATA2, SCL/TAL1 and FLI1) and three diagnostic histone modification marks with the gene expression changes that occur during development of primary megakaryocytes (MEG) and erythroblasts (ERY) from murine fetal liver hematopoietic stem/progenitor cells. We identified a robust, genome-wide mechanism of MEG-specific lineage priming by a previously described stem/progenitor cell-expressed transcription factor heptad (GATA2, LYL1, SCL/TAL1, FLI1, ERG, RUNX1, LMO2) binding to MEG-specific cis-regulatory modules in multipotential hematopoietic progenitors. This is followed by genome-wide GATA factor switching that mediates further induction of MEG-specific genes following lineage commitment. Interaction between GATA and ETS factors appears to be a key determinant of these processes. In contrast, ERY-specific lineage priming occurs is biased toward GATA2-independent mechanisms. In addition to its role in MEG lineage priming, GATA2 plays an extensive role in late megakaryopoiesis as a transcriptional repressor at loci defined by a specific DNA signature. Our findings reveal important new insights into how ERY and MEG lineages arise from a common bipotential precursor via overlapping and divergent functions of shared hematopoietic transcription factors.
Divergent functions of hematopoietic transcription factors in lineage priming and differentiation during erythro-megakaryopoiesis.
Specimen part
View SamplesMitochondria control bioenergetics and cell fate decisions, but whether they also participate in extra-organelle signaling is not understood. Here, we show that interference with cyclophilin D (CypD), a mitochondrial matrix protein and apoptosis regulator, causes accelerated cell proliferation and enhanced cell migration and invasion. These responses are associated with global transcriptional changes in CypD-/- cells, predominantly affecting chemokines and their receptors, and resulting in increased activating phosphorylation of Signal Transduction and Activator of Transcription 3 (STAT3). In turn, STAT3 signaling promotes increased proliferation of CypD-/- cells via accelerated S-phase entry and supports Cxcl12-directed paracrine cell motility. Therefore, mitochondria-to-nuclei transcriptional signaling globally affects cell division and motility. As immunosuppressive therapies often target CypD, this pathway may predispose the tissue microenvironment of these patients to oncogenic transformation.
Cyclophilin D extramitochondrial signaling controls cell cycle progression and chemokine-directed cell motility.
Specimen part
View SamplesIdentifying the functions of proteins, which define specific subnuclear structures and territories, is important for understanding eukaryotic nuclear dynamics. Sp100 is a prototypical protein of ND10/PML bodies and co-localizes with the proto-oncogenic protein PML and Daxx, proteins with critical roles in oncogenic transformation, interferon-mediated viral resistance and response to PML-directed cancer therapeutics. Sp100 isoforms contain PHD, Bromo and HMG domains and are highly sumoylated at ND10/PML bodies, all characteristics suggestive of a role in chromatin mediated gene regulation. However, no clear role for the Sp100 component of PML bodies in oncogenesis has been defined. Using isoform-specific knockdown techniques, we show that most human diploid fibroblasts, which lack Sp100, rapidly senesce and discuss gene expression changes associated with this rapid senescence.
Sp100 as a potent tumor suppressor: accelerated senescence and rapid malignant transformation of human fibroblasts through modulation of an embryonic stem cell program.
Cell line, Treatment
View SamplesThe role of myeloid cells as regulators of tumor progression that significantly impact the efficacy of cancer immunotherapies makes them an attractive target for inhibition. Here we explore the effect of a novel, potent, and selective inhibitor of serine/threonine protein kinase CK2 on modulating myeloid cells in the tumor microenvironment. Although inhibition of CK2 caused only a modest effect on dendritic cells in tumor-bearing mice, it substantially reduced the amount of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC) and tumor-associated macrophages (TAM). This effect was not caused by the induction of apoptosis, but rather by a block of differentiation. Our results implicated downregulation of CCAAT-enhancer binding protein-a (C/EBPa) in this effect. Although CK2 inhibition did not directly affect tumor cells, it dramatically enhanced the antitumor activity of immune checkpoint receptor blockade using anti-CTLA-4 antibody. These results suggest a potential role of CK2 inhibitors in combination therapies against cancer. Overall design: Untreated and CK2 inhibitor treated hematopoietic progenitor cells cells assayed by RNA-seq
Inhibition of Casein Kinase 2 Disrupts Differentiation of Myeloid Cells in Cancer and Enhances the Efficacy of Immunotherapy in Mice.
Specimen part, Cell line, Subject
View SamplesKaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi's sarcoma (KS). In sub-Saharan Africa, the high prevalence of both HIV-1 and KSHV has made KS a leading cancer in the region, associated with poor prognosis and high mortality due to late medical presentation and advanced disease stages. A better understanding of the cellular and viral transcriptome profiles during neoplastic growth will aid in the definition of biomarkers and cellular functions associated with KS tumorigenesis and progression. Our approach is to examine the transcriptome profile in actual KS lesions versus non-cancer tissues from the same individual for a total of four male African epidemic KS patients. These patients have undetectable HIV-1 plasma viral load after successful anti-retroviral therapy. Our results capture the cellular complexity of in vivo lesion environment and provide a marked contrast to those derived from in vitro monoculture models. The findings demonstrate that latency and immune modulation related functions dominate the viral gene expression pattern. Moreover, KSHV significantly affected the cellular transcriptome profile with genes involved in lipid and glucose metabolism disorder pathways being the most substantially dysregulated. Despite the implied infiltration of immune cells into the lesions as predicted by CIBERSORT, KS tumor continued to progress, suggesting immunological dysfunction in these KS patients despite control of HIV-1 viremia. Lastly, there is limited overlap of our in vivo dataset with in vitro studies, suggesting a limitation of in vitro KS models. Overall design: RNA-seq of Kaposi's sarcoma lesions and control tissues
RNA-Seq of Kaposi's sarcoma reveals alterations in glucose and lipid metabolism.
Specimen part, Subject
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