Project description:To find genes deregulated in the pathogenisis of T-cells in Atm deficient mice, we performed expression profiling of Atm deficient thymic lymphomas, wildtype thymi and Atm deficient thymi without macroscopic enlargement, representing an intermediate stage in the process of tumorigenisis. Keywords: genetic modification, disease state analysis
Project description:Ataxia-telangiectasia mutated (ATM) kinase plays a central role in maintaining genomic integrity. In both humans and mice, ATM deficiency is associated with an increased incidence of lymphoid cancers that are primarily T cell in origin. We demonstrate here that when T cells are removed as targets for lymphomagenesis and as mediators of immune surveillance, ATM-deficient mice exclusively develop early onset IgM+ B cell lymphomas that by histology and gene expression profiling resemble the activated B cell-like (ABC) subset of human diffuse large B cell lymphomas (DLBCL). These ATM-deficient B cell tumors show considerable chromosomal instability and a recurrent genomic amplification of a 4.48 Mb region on chromosome 18 that contains Malt1 and is orthologous to a region similarly amplified in human ABC-DLBCL. Further, the amplification of Malt1 in these lymphomas correlates with their dependence on NF-kB, MALT1, and BCR signaling for survival, paralleling human ABC-DLBCL. This study reveals that ATM protects against development of B cell lymphomas that model human ABC-DLBCL and identifies a role for T cells in preventing the emergence of these tumors.
Project description:Ataxia-telangiectasia mutated (ATM) kinase plays a central role in maintaining genomic integrity. In both humans and mice, ATM deficiency is associated with an increased incidence of lymphoid cancers that are primarily T cell in origin. We demonstrate here that when T cells are removed as targets for lymphomagenesis and as mediators of immune surveillance, ATM-deficient mice exclusively develop early onset IgM+ B cell lymphomas that by histology and gene expression profiling resemble the activated B cell-like (ABC) subset of human diffuse large B cell lymphomas (DLBCL). These ATM-deficient B cell tumors show considerable chromosomal instability and a recurrent genomic amplification of a 4.48 Mb region on chromosome 18 that contains Malt1 and is orthologous to a region similarly amplified in human ABC-DLBCL. Further, the amplification of Malt1 in these lymphomas correlates with their dependence on NF-kB, MALT1, and BCR signaling for survival, paralleling human ABC-DLBCL. This study reveals that ATM protects against development of B cell lymphomas that model human ABC-DLBCL and identifies a role for T cells in preventing the emergence of these tumors. We performed gene expression profiling on nine ATMKO.CD3epsilonKO lymphoma cell lines (n=12, 3 technical repeats). We analyzed gene expression of anti-IgM stimulated primary B cells from both ATMKO.CD3epsilonKO (n=7, 5 technical repeats) and ATMWT.CD3epsilonKO mice (n=2), and GC B cells isolated from SRBC-immunized ATMWT mice (n=3, 1 biological repeat and 2 technical repeats). We analyzed gene expression following treatment of two ATMKO.CD3epsilonKO lymphoma cell lines with the BTK inhibitor, PCI-32765, at time points (1, 3, 6, and 24 hours) as compared to time points with vehicle (DMSO) (n=8).
Project description:We used microarray profiling to document the difference between telomerase+ vs. ALT+ T-cell lymphomas developed on G3 Atm-/-TERT-ER genetic background. T-cell lymphomas were developed in G3 Atm-/-TERT-ER mice with 4-OHT treatment. These cells were either maintained on SCID mice treated with 4-OHT or vehicle. Cells maintained on vehicle eventually developed ALT-dependent resistance. We used microarray to profile telomerase+ tumors vs. ALT+ tumors from the same parental lines.
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).
Project description:We used microarray profiling to document the difference between telomerase+ vs. ALT+ T-cell lymphomas developed on G3 Atm-/-TERT-ER genetic background.
Project description:Lck-MyrAkt2 mice develop spontaneous thymic lymphomas at approximately 100-200 days of age, driven in part by a consitutatively-active AKT (due to myristoylation). mTOR Knock Down mice were crossed with Lck-MyrAkt postive mice to model the affects of decreasing mTOR activity on tumors with an activated PI3K/AKT/MTOR pathway. Lck-Akt/mTOR KD mice had prolonged survival compared to the Lck-Akt/mTOR WT mice. We used microarrays to compare the transcriptome in thymic lymphomas between Lck-Akt positive, mTOR WT and Lck-Akt positive, mTOR KD mice. Four thymic lymphomas from Lck-Akt/mTOR WT mice were compared to three thymic lymphomas from Lck-Akt/mTOR KD mice.