Project description:TET2 is an enzyme for converting methylcytosine (mC) to hydorxymethylcytosine (hmC) and its mutations have been frequently found in myeloid malignancies and T-cell lymphoma in humans. We analyzed Tet2 gene trap mice and found that homozygous mice developed T-cell lymphoma with follicular helper T-cell-like features. To examine comprehensive gene expression patterns of lymphoma cells, We performed gene expression analysis using lymphoma cells in homozygousTet2 gene trap mice and CD4+ control cells.
Project description:FYN-TRAF3IP2 expression in hematopoietic progenitors induces T cell transformation in mice and cooperates with loss of the Tet2 tumor suppressor in PTCL development. To investigate the oncogenic activity of FYN-TRAF3IP2, we analyzed the lymphomagenic effects of expressing this gene fusion alone and in cooperation with loss of the Tet2 tumor suppressor gene in vivo. In these experiments, we first infected hematopoietic progenitors from CD4-specific tamoxifen-inducible Cre Tet2 conditional knockout mice (CD4 Cre-ERT2, Tet2fl/fl) with bicistronic retroviruses expressing wild type TRAF3IP2 and GFP, FYN-TRAF3IP2 and GFP, or GFP alone and injected these intravenously into isogenic recipients. Transplanted mice were then treated with vehicle only, to test the oncogenic effects of TRAF3IP2, FYN-TRAF3IP2 or GFP expression; or with tamoxifen, to evaluate the effects of TRAF3IP2, FYN-TRAF3IP2 or GFP expression in concert with genetic loss of Tet2 in CD4 T cells. In this setting, all animals transplanted with GFP-expressing progenitors remained lymphoma free at the end of follow up and one animal transplanted with wild type TRAF3IP2 GFP expressing cells developed a CD8+ T cell lymphoma. In contrast, 4/10 (40%) vehicle treated mice transplanted with FYN-TRAF3IP2-expressing cells and 5/10 (50%) tamoxifen treated mice transplanted with FYN-TRAF3IP2-expressing cells developed clonal CD4-restricted mature T cell lymphomas. To further analyze the lymphomagenic effect of the fusion gene, we performed transcriptomic profiling of FYN-TRAF3IP2-induced mouse CD4+ GFP+ PTCL tumor lymphocytes compared with normal mouse CD4+ T cells by RNAseq.
Project description:Angioimmunoblastic T-cell lymphoma, a subtype of T-cell lymphoma, is a disease with relative poor outcome. Genetic analysis in human samples showed the co-existence of common mutations in TET2 and RHOA genes. We have made a mouse model resembling the genetic lesions in human AITL. Our mice developed AITL-like lymphoma after 40 weeks old. We analyzed the expression of transcriptomes in WT- and Tet2-/-G17VRHOA-CD4 splenocytes to find out the underlying pathogenesis mechanism of AITL.
Project description:Angioimmunoblastic T cell lymphoma (AITL) represents a distinctive form of peripheral T cell lymphoma with a dismissal prognosis. Recent exome sequencing in AITL patients revealed frequent coexistence of somatic mutations in the RHO GTPase (RHOAG17V) and the 5-methylcytosine oxidase TET2. Here we demonstrated that Tet2 loss and RhoAG17V cooperatively caused abnormal CD4+ T cell proliferation and differentiation by perturbing FoxO1 gene expression and its subcellular localization, an abnormality that is also detected in AITL tumor samples. Re-expression of FoxO1 attenuated aberrant immune responses induced by genetic lesions in both Tet2 and RhoA. Our findings suggest that mutational cooperativity between epigenetic factors and GTPases in adult CD4+ T cells may account for immunoinflammatory responses that are commonly associated with AITL.
Project description:Early events mediated by cancer progression remain relative unknown. Here, we provide analysis of CD4 T cells derived from C57Bl/6 mice transplanted with Eu-Myc lymphoma cells at earlyand late time points versus CD4 T cells derived from non-tumor-bearing control mice. Our data indicate that CD4 T-cell differentiation and fate is not provoked until late in tumor growth. These studies demonstrate when CD4 T-cell gene expression might change in the course of lymphoma progression.
Project description:We studied the effects of loss of TET proteins in regulatory T cells in mice and compared the transcriptional profiles in Treg cells and CD4+ T cells isolated from WT and Tet2/3 DKO mice
Project description:In this study, we investigated the role of Tet2 in regulation of hematopoietic genes by performing transcriptomic analysis of Tet2 WT, Mut, and KO LSK and Lin– cells at 3, 6, 9, and 12 months by RNA-seq, and mapping the DNA methylation landscape of 3-month-old Tet2 WT, Mut, and KO LSK and Lin– cells. (1) We find that loss of Tet2 (Tet2 KO) vs. a loss of Tet2 catalytic function (Tet2 Mut) at different time points and cell types causes distinct gene expression changes when compared to WT samples as assessed by RNA-seq. (2) Additionally, we find that many genes implicated in lymphoma and leukemia are deregulated in Tet2 Mut and KO LSK and Lin– cells, consistent with the phenotypes observed in mice transplanted with Tet2 Mut and KO bone marrow. (3) We also mapped genome-wide DNA methylation levels of WT, Tet2 Mut, and KO LSK and Lin– cells at 3 months by WGBS and establish a role for Tet2 in demethylating genes implicated in lymphoma and leukemia initiation and progression.
Project description:TET1/2/3 are methylcytosine dioxygenases regulating cytosine hydroxymethylation in the genome. Tet1 and Tet2 are abundantly expressed in HSC/HPCs and implicated in the pathogenesis of hematological malignancies. Tet2-deletion in mice causes myeloid malignancies, while Tet1-null mice develop B-cell lymphoma after an extended period of latency. Interestingly, TET1 and TET2 were often concomitantly down-regulated in acute B-lymphocytic leukemia. Here, we investigated the overlapping and non-redundant functions of Tet1/Tet2 in HSC maintenance and development of hematological malignancies using Tet1/2 double knockout (DKO) mice. DKO and Tet2-/- HSC/HPCs had overlapping and unique 5hmC and 5mC profiles and behaved differently. DKO mice exhibited strikingly decreased incidence and delayed onset of myeloid malignancies compared to Tet2-/- mice and in contrast developed lethal B-cell malignancies. Transcriptome analysis of DKO tumors revealed expression changes in many genes dysregulated in human B-cell malignancies, such as LMO2, BCL6 and MYC. These results highlight the critical roles of TET1 or TET2 individually and their cross-talks in the pathogenesis of hematological malignancies. Given the role of Tet proteins in 5mC oxidation, we employed a previously established chemical labeling and affinity purification method coupled with high-throughput sequencing (hMe-Seal) to profile the genome-wide distribution of 5hmC, as well as methylated DNA immunoprecipitation (MeDIP) coupled with high-throughput sequencing (MeDIP-seq) to profile 5mC using BM LK cells purified from young WT, Tet2-/- and DKO mice (6-10 wks old).
Project description:Genome wide DNA methylation profiling of patient samples with TET2 mutations and Wild type TET2 status . The Illumina Infinium HumanMethylation 450_15017482_v.1.1 was used to obtain DNA methylation profiles across approximately 482,421 CpGs in fresh frozen lymphoma samples. Samples include 19 TET2 wild type and 12 TET2 mutant samples.
Project description:Genome wide DNA methylation profiling of patient samples with TET2 mutations and Wild type TET2 status . The Illumina Infinium HumanMethylation 450_15017482_v.1.1 was used to obtain DNA methylation profiles across approximately 482,421 CpGs in fresh frozen lymphoma samples. Samples include 19 TET2 wild type and 12 TET2 mutant samples. Bisulphite converted DNA from the 31 samples were hybridised to the Illumina Infinium HM450K Human Methylation Beadchip v1.2