Ikaros deficient mouse thymic lymphomas
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE23972 | GEO | 2010/09/03
SECONDARY ACCESSION(S): PRJNA130489
REPOSITORIES: GEO
Similar Datasets
Project description:This dataset comprises expression profiles from 3 thymic lymphomas from Ikaros deficient mice (IkL/L model, see Dumortier et al, Mol. Cell. Biol. 26, 209-220, 2006 for a description of the tumor model) and 3 thymic lymphomas from IkL/L mice that harbor a mutation of the Notch1 gene (deletion of floxed sequences comprising the promoter and exon 1 with the CD4-Cre transgene). The results from this experimpent is that the expression of Notch target genes was unexpectedly not altered in the tumors with the Notch1 deletion. This result is explained by the activation of a cryptic 3' Notch1 promoter in the deleted tumors, which leads to constitutive Notch1 activation. These results are described in the following publication: R Jeannet, J Mastio, B Macias-Garcia, A Oravecz, T Ashworth, AS Geimer-Lelay, B Jost, S Le Gras, J Ghysdael, T Gridley, T Honjo, F Radtke, J Aster, S Chan and P Kastner. Oncogenic activation of the Notch1 gene in mouse T-cell leukemia by deletion of its promoter. Blood, in press (2010) Primary thymic tumors from 3 IkL/L Notch1+/+ CD4-Cre+ mice (aged 18-20 weeks) were compared to similar tumors from 3 IkL/L Notch1f/f CD4-Cre+ mice (aged 8-10 weeks).
2010-09-03 | E-GEOD-23972 | biostudies-arrayexpress
Project description:Inactivation of Pten occurs by multiple mechanisms including epigenetic silencing, point mutations, insertion, and deletion, which are tissue dependent. Although frequent loss of heterozygosity around Pten locus and plausible involvement of epigenetic silencing have been reported in radiation-induced thymic lymphomas, the frequency of Pten inactivation and the spectrum of causal aberrations have not yet been extensively characterized. Here, we assessed the principal mode of inactivation by comprehensively analyzing expression and alterations of Pten gene in 23 radiation-induced thymic lymphomas developed in B6C3F1 mice. We found no evidence for methylation-associated silencing of Pten gene. Instead, we found complex structural abnormalities in 8 lymphomas (35%) that included missense and nonsense mutations, 1- and 3-bp insertions, and focal deletions. Sequencing of deletion breakpoints suggested that illegitimate V(D)J recombination and microhomology-mediated rearrangement were responsible for the focal deletions. Seven out of these 8 lymphomas had biallelic alterations, and 4 of them did not express any Pten protein. These aberrations of Pten were well coincided with downstream Akt phosphorylation on Ser473. In conclusion, Pten inactivation, which is frequently biallelic and is caused by a variety of structural abnormalities but not by epigenetic silencing, is involved in radiation-induced lymphomagenesis. Three thymic lymphomas were analyzed by array-CGH method.
2010-05-06 | E-GEOD-17751 | biostudies-arrayexpress
Project description:The HMG-box factor Tcf1 is required during T-cell development in the thymus and mediates the nuclear response to Wnt signals. Tcf1-/- mice have previously been characterized and show developmental blocks at the CD4-CD8- double negative (DN) to CD4+CD8+ double positive transition. Due to the blocks in T-cell development, Tcf1-/- mice normally have a very small thymus. Unexpectedly, a large proportion of Tcf1-/- mice spontaneously develop thymic lymphomas with 50% of mice developing a thymic lymphoma/leukemia at the age of 16 wk. These lymphomas are clonal, highly metastatic, and paradoxically show high Wnt signaling when crossed with Wnt reporter mice and have high expression of Wnt target genes Lef1 and Axin2. In wild-type thymocytes, Tcf1 is higher expressed than Lef1, with a predominance of Wnt inhibitory isoforms. Loss of Tcf1 as repressor of Lef1 leads to high Wnt activity and is the initiating event in lymphoma development, which is exacerbated by activating Notch1 mutations. Thus, Notch1 and loss of Tcf1 functionally act as collaborating oncogenic events. Tcf1 deficiency predisposes to the development of thymic lymphomas by ectopic up-regulation of Lef1 due to lack of Tcf1 repressive isoforms and frequently by cooperating activating mutations in Notch1. Tcf1 therefore functions as a T-cell‚Äìspecific tumor suppressor gene, besides its established role as a Wnt responsive transcription factor. Thus, Tcf1 acts as a molecular switch between proliferative and repressive signals during T-lymphocyte development in the thymus. Using the Tcf1-/- DeltaVII/DeltaVII knockout mouse (Verbeek et al. Nature 1995), thymocytes of 17 mice (5 control Tcf+/-, 4 Tcf-/- and 8 Tcf-/- with thymic lymphoma) were homogenized for RNA isolation using Qiagen RNeasy minicolumns. The quantity and quality of total RNA was determined using spectrophotometry (Nanodrop) and an Agilent Bioanalyzer. One ¬µg of RNA was used to generate cRNA using Affymetrix One cycle cDNA synthesis kit (Affymetrix, Santa Clara, CA, USA), after which the samples were biotinylated using an Affymetrix IVT labeling kit (Affymetrix). The samples were hybridized overnight at 42¬?C to GeneChip mouse genome 430 2.0 Arrays (Affymetrix). Washing and staining steps were performed on a Fluidics station 450, and the Genechips were scanned using a GeneChip scanner 3000 (Affymetrix) at the Department of Immunology, Erasmus Medical Center. Raw data were normalized and summarized using Robust Multichip Average (RMA) method. The experiment consists of 5 control Tcf+/- thymi, 4 Tcf-/- thymi and 8 Tcf-/- thymus samples with thymic lymphoma.
2014-02-14 | E-GEOD-54976 | biostudies-arrayexpress
Project description:Expression profiling of thymic lymphomas derived from HIF1a+/+, p53R270H/R270H; HIF1a+/-, p53R270H/R270H; and HIF1aKI/+, p53R270H/R270H mice. HIF1a and HIF2a share a high degree of sequence homology, but recent work has shown that the two a subunits can have contrasting and tissue-specific effects on tumor growth. To directly compare the role of each HIFa subunit in spontaneous tumorigenesis, we bred a mouse model of expanded HIF2a expression and Hif1a+/- mice to homozygotes for the R270H mutation in p53. Heterozygosity for Hif1a significantly reduced the incidence of thymic lymphomas observed in this model. Moreover, reduced Hif1a levels correlated with decreased stabilization of activated Notch1 and expression of the Notch target genes, Dtx1 and Nrarp. Keywords: genetic modification, disease state analysis Thymic lymphoma tissue was preserved at the time mice were sacrificed. 4-5 samples from each of 3 genotypes (HIF1a+/-, p53R270H/R270H, HIF1aKI/+; p53R270H/R270H; and HIF1a+/+, p53R270H/R270H) were then used for microarray analysis to identify differences in gene expression that could account for changes in tumor onset and incidence.
2009-01-12 | E-GEOD-14336 | biostudies-arrayexpress
Project description:Notch1 signaling is absolutely essential for steady-state thymic lymphopoiesis, but the role of other Notch receptors, and their potential overlap with the function of Notch1, remains unclear. Here we show that like Notch1, Notch3 is differentially expressed by progenitor thymocytes, peaking at the DN3 progenitor stage. Using mice carrying a gene-trapped allele, we show that thymic cellularity is slightly reduced in the absence of Notch3, although progression through the defined sequence of TCR-αβ development is normal, as are NKT and TCRγδ cell production. The absence of a profound effect from Notch3 deletion is not explained by residual function of the gene-trapped allele, since insertion mapping suggests that the targeted allele would not encode functional signaling domains. We also show that although Notch1 and Notch3 are co-expressed on some early intrathymic progenitors, the relatively mild phenotype seen after Notch3 deletion does not result from the compensatory function of Notch1, nor does Notch3 function explain the likewise mild phenotype seen after conditional (intrathymic) deletion of Notch1. Our studies indicate that Notch1 and Notch3 carry out non-overlapping functions during thymocyte differentiation, and that while Notch1 is absolutely required early in the lymphopoietic process, neither receptor is essential at later stages.
2011-08-03 | GSE30631 | GEO
Project description:Expression profiling of thymic lymphomas derived from HIF1a+/+, p53R270H/R270H; HIF1a+/-, p53R270H/R270H; and HIF1aKI/+, p53R270H/R270H mice. HIF1a and HIF2a share a high degree of sequence homology, but recent work has shown that the two a subunits can have contrasting and tissue-specific effects on tumor growth. To directly compare the role of each HIFa subunit in spontaneous tumorigenesis, we bred a mouse model of expanded HIF2a expression and Hif1a+/- mice to homozygotes for the R270H mutation in p53. Heterozygosity for Hif1a significantly reduced the incidence of thymic lymphomas observed in this model. Moreover, reduced Hif1a levels correlated with decreased stabilization of activated Notch1 and expression of the Notch target genes, Dtx1 and Nrarp. Keywords: genetic modification, disease state analysis
2009-01-12 | GSE14336 | GEO
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Project description:Activated phosphoinositide 3-kinase (PI3K)-AKT signaling appears to be an obligate event in the development of cancer. The highly related members of the mammalian FoxO transcription factor family, FoxO1, FoxO3, and FoxO4, represent one of several effector arms of PI3K-AKT signaling, prompting genetic analysis of the role of FoxOs in the neoplastic phenotypes linked to PI3K-AKT activation. While germline or somatic deletion of up to five FoxO alleles produced remarkably modest neoplastic phenotypes, broad somatic deletion of all FoxOs engendered a progressive cancer-prone condition characterized by thymic lymphomas and hemangiomas, demonstrating that the mammalian FoxOs are indeed bona fide tumor suppressors. Transcriptome and promoter analyses of differentially affected endothelium identified direct FoxO targets and revealed that FoxO regulation of these targets in vivo is highly context-specific, even in the same cell type. Functional studies validated Sprouty2 and PBX1, among others, as FoxO-regulated mediators of endothelial cell morphogenesis and vascular homeostasis.
2011-03-16 | GSE27932 | GEO
Project description:The HMG-box factor Tcf1 is required during T-cell development in the thymus and mediates the nuclear response to Wnt signals. Tcf1−/− mice have previously been characterized and show developmental blocks at the CD4−CD8− double negative (DN) to CD4+CD8+ double positive transition. Due to the blocks in T-cell development, Tcf1−/− mice normally have a very small thymus. Unexpectedly, a large proportion of Tcf1−/− mice spontaneously develop thymic lymphomas with 50% of mice developing a thymic lymphoma/leukemia at the age of 16 wk. These lymphomas are clonal, highly metastatic, and paradoxically show high Wnt signaling when crossed with Wnt reporter mice and have high expression of Wnt target genes Lef1 and Axin2. In wild-type thymocytes, Tcf1 is higher expressed than Lef1, with a predominance of Wnt inhibitory isoforms. Loss of Tcf1 as repressor of Lef1 leads to high Wnt activity and is the initiating event in lymphoma development, which is exacerbated by activating Notch1 mutations. Thus, Notch1 and loss of Tcf1 functionally act as collaborating oncogenic events. Tcf1 deficiency predisposes to the development of thymic lymphomas by ectopic up-regulation of Lef1 due to lack of Tcf1 repressive isoforms and frequently by cooperating activating mutations in Notch1. Tcf1 therefore functions as a T-cell–specific tumor suppressor gene, besides its established role as a Wnt responsive transcription factor. Thus, Tcf1 acts as a molecular switch between proliferative and repressive signals during T-lymphocyte development in the thymus. Using the Tcf1−/− ΔVII/ΔVII knockout mouse (Verbeek et al. Nature 1995), thymocytes of 17 mice (5 control Tcf+/-, 4 Tcf-/- and 8 Tcf-/- with thymic lymphoma) were homogenized for RNA isolation using Qiagen RNeasy minicolumns. The quantity and quality of total RNA was determined using spectrophotometry (Nanodrop) and an Agilent Bioanalyzer. One µg of RNA was used to generate cRNA using Affymetrix One cycle cDNA synthesis kit (Affymetrix, Santa Clara, CA, USA), after which the samples were biotinylated using an Affymetrix IVT labeling kit (Affymetrix). The samples were hybridized overnight at 42°C to GeneChip mouse genome 430 2.0 Arrays (Affymetrix). Washing and staining steps were performed on a Fluidics station 450, and the Genechips were scanned using a GeneChip scanner 3000 (Affymetrix) at the Department of Immunology, Erasmus Medical Center. Raw data were normalized and summarized using Robust Multichip Average (RMA) method.
2014-02-14 | GSE54976 | GEO
