Induction of the Arf tumor suppressor in response to hyperproliferative stress following oncogene activation activates a p53-dependent transcriptional program that limits the expansion of incipient cancer cells. Although Arf is not expressed in most tissues of fetal or young adult mice, it is physiologically expressed in the fetal yolk sac, a tissue derived from the extraembryonic endoderm. We demonstrate that expression of the mouse p19Arf protein marks late stages of extraembryonic endoderm differentiation in cultured embryoid bodies derived from either embryonic stem cells or induced pluripotent stem cells, and that Arf inactivation specifically delays the differentiation of the extraembryonic endoderm lineage, but not the formation of other germ cell lineages from pluripotent progenitors. Arf is required for the timely induction of extraembryonic endodermal cells in response to Ras/Erk signaling and, in turn, acts through p53 to ensure extraembryonic endoderm lineage development, but not maintenance. Remarkably, a significant temporal delay in extraembryonic endoderm differentiation detected during the maturation of Arf-null embryoid bodies is rescued by enforced expression of miR-205, a micro-RNA up-regulated by p19Arf and p53. Introduction of miR-205 into Arf-null embryonic stem cells rescues defective ExEn formation and elicits a program of gene expression that controls the migration and adhesion of embryonic endodermal cells. This occurs, at least in part, through atypical regulation of genes that control the epithelial-to-mesenchymal transition in cancer cells. Our findings suggest that noncanonical and canonical roles of Arf in extraembryonic endoderm development and tumor suppression, respectively, may be conceptually linked through mechanisms that govern cell-to-cell attachment and migration.
Arf tumor suppressor and miR-205 regulate cell adhesion and formation of extraembryonic endoderm from pluripotent stem cells.
Specimen part, Treatment
View SamplesMyc-driven Group 3 medulloblastoma (MB) is the most aggressive tumor among the four subgroups classified by transcriptome, genomic landscape and clinical outcomes. So far in all available mouse Group 3 models, the constitutive ectopic Myc expression was under control of LTR element or other exogenous promoters within the vectors, which were randomly inserted into the genome with multiple copies. Here we are deploying nuclease deficient CRISPR/dCas9-based transactivator that is targeted to promoter DNA sequences by specific guide RNA to force the transcriptional activation of endogenous Myc in p53-/-;cdkn2c-/- neurospheres cells. A combination of three sgRNAs together with dCas9-VP64 induced the highest expression of endogenous Myc. When the targeted cells were transplanted to the cortex of recipients, tumors arose fully recapitulate the Group 3 MB in human. This novel mouse model should significantly strengthen our understanding and treatment of the Myc-driven Group 3 medulloblastoma.
Mouse medulloblastoma driven by CRISPR activation of cellular Myc.
Specimen part
View SamplesDicer1 loss in the aP2-lineage leads to the development of aggressive and highly penetrant angiosarcomas independent of other oncogenes or tumor suppressor loss
Biallelic <i>Dicer1</i> Loss Mediated by <i>aP2-Cre</i> Drives Angiosarcoma.
Specimen part
View SamplesInvestigation of immune-cell differentiation and function is limited by shortcomings of suitable and scalable experimental systems. Here we show that retroviral delivery of an estrogen-regulated form of Hoxb8 into mouse bone marrow cells can be used along with Flt3 ligand to conditionally immortalize early hematopoietic progenitor cells (Hoxb8-FL cells). Hoxb8-FL cells have lost self-renewal capacity and potential to differentiate into megakaryocytes and erythrocytes but retain the potential to differentiate into myeloid and lymphoid cells. They differentiate in vitro and in vivo into macrophages, granulocytes, dendritic cells, B lymphocytes and T lymphocytes that are phenotypically and functionally indistinguishable from their primary counterparts. Quantitative in vitro assays indicate that myeloid and B-cell potential of Hoxb8-FL cells is comparable to that of primary lymphoid-primed multipotent progenitors, whereas T-cell potential is diminished. The simplicity of this system and the unlimited proliferative capacity of Hoxb8-FL cells will enable studies of immune-cell differentiation and function.
Hematopoietic progenitor cell lines with myeloid and lymphoid potential.
Specimen part
View SamplesThis study set out to identify MLX transcriptional targets in muscle cells. C2C12 Myoblasts were virally transduced to increase MLX activity, by overexpression of the wild-type protein; and to decrease MLX activity by overexpression of a dominant negative MLX protein and by shRNA induced knockdown of MLX. Transcripts that were significantly and consistently regulated by the different modes of MLX modulation were identified. The largest proportion of these were genes encoding secreted proteins including growth factors, cytokines and extracellular proteins. We therefore conclude that MLX can regulate myokine transcripts. Overall design: mRNA profiles from C2C12 muscle cells with increased and decreased MLX activity were examined.
The glucose-sensing transcription factor MLX promotes myogenesis via myokine signaling.
No sample metadata fields
View SamplesGenetic fate mapping was preformed on aP2-Cre;tdTomato and aP2-Cre;tdTomato;SmoM2/+ animals and endothelial progenitor cells identified as the cell of origin of FN-RMS in aP2-Cre;SmoM2/+ animals
Hedgehog Pathway Drives Fusion-Negative Rhabdomyosarcoma Initiated From Non-myogenic Endothelial Progenitors.
Specimen part
View SamplesGenes regulated by miR-206 were identified by microarray analysis in RD cells transfected with a Negative Control (NC) or miR-206 Mimic
PAX7 is a required target for microRNA-206-induced differentiation of fusion-negative rhabdomyosarcoma.
Specimen part, Cell line, Time
View SamplesActivation of Sonic Hedgehog signaling through expression of a constitutively active Smoothened allele under control of an aP2 adipocyte-restricted transgene in mice gives rise to aggressive skeletal muscle tumors that display the histologic and molecular characteristics of human embryonal rhabdomyosarcoma with high penetrance.
A mouse model of rhabdomyosarcoma originating from the adipocyte lineage.
Specimen part
View SamplesRecognition and response to gram-positive bacteria by macrophages and dendritic cells is mediated in part through TLR2. We found that that Streptococcus pneumoniae cell wall fragments, containing primarily peptidoglycan and teichoic acids, induced prodigious secretion of IL-10 from macrophages and dendritic cells and was dependent on TLR2 and NOD2, a cytoplasmic CARD-NACHT-LRR protein encoded by Card15. IL-10 secretion in response to cell walls was also dependent on RICK/RIP2, a kinase associated with NOD2, and MYD88 but independent of the ERK/p38 pathway. The reduction of IL-10 secretion by cell wall-activated NOD2-deficient myeloidderived cells translated into downstream effects on IL-10 target gene expression and elevations in subsets of pro-inflammatory cytokine expression normally restrained by autocrine/paracrine effects of IL-10. Since NOD2 is linked to aberrant immune responses in Crohns Disease patients bearing mutations in CARD15, the temporal and quantitative effects of the TLR2/NOD/RICK pathway on IL-10 secretion may affect homeostatic control of immune responses to gram-positive bacteria.
The TLR2-MyD88-NOD2-RIPK2 signalling axis regulates a balanced pro-inflammatory and IL-10-mediated anti-inflammatory cytokine response to Gram-positive cell walls.
No sample metadata fields
View SamplesMalignant glioblastoma (GBM) is a highly aggressive brain tumor with a dismal prognosis and limited therapeutic options. Genomic profiling of GBM samples in the TCGA database has identified four molecular subtypes (Proneural, Neural, Classical and Mesenchymal), which may arise from different glioblastoma stem-like cell (GSC) populations. In the present study, we identify two GSC populations that produce GBM tumors by subcutaneous and intracranial injection with identical histological features. Gene expression analysis revealed that xenografts of GSCs grown as spheroid cultures had a Classical molecular subtype similar to that of bulk tumor cells. In contrast xenografts of GSCs grown as adherent cultures on laminin-coated plates expressed a Mesenchymal gene signature. Adherent GSC-derived xenografts had high STAT3 and ANGPTL4 expression as well as enrichment for stem cell markers, transcriptional networks and pro-angiogenic markers characteristic of the Mesenchymal subtype. Examination of clinical samples from GBM patients showed that STAT3 expression was directly correlated with ANGPTL4 expression, and that increased expression of these genes correlated with poor patient survival and performance. A pharmacological STAT3 inhibitor abrogated STAT3 binding to the ANGPTL4 promoter and exhibited anticancer activity in vivo. Taken together, we identified two distinct GSC populations that produce histologically identical tumors but with very different gene expression patterns, and a STAT3/ ANGPTL4 pathway in glioblastoma that may serve as a target for therapeutic intervention.
Molecular heterogeneity in a patient-derived glioblastoma xenoline is regulated by different cancer stem cell populations.
Specimen part
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