Project description:Methylation data from normal thymocytes, 24 day pre-tumor Dnmt3b-deficient thymocytes, Wild-Type Tumors, and Dnmt3b-deficient Tumors
Project description:The TAL1/SCL and LMO1 oncogenic transcription factors establish a pre-leukemic state by reprogramming thymocytes into self-renewing pre-leukemic stem cells (pre-LSCs). Pre-TCR signaling accelerates the progression to T-cell acute lymphoblastic leukemia (T-ALL). To directly address the importance of pre-TCR signaling in driving progression to T-ALL, we leverage on Cd3-deficient mice in which pre-TCR signaling and progression through β-selection is abrogated. In the absence of pre-TCR signaling in Cd3ε-deficient SCL-LMO1 transgenic mice, T-ALL onset is delayed by 150 days. Despite the absence of pre-TCR/CD3 signaling in these mice, we show that leukemic thymocytes exhibit the gene expression profiles of thymocytes that have undergone β-selection, i.e. exhibiting a re-activation of pre-TCR-driven proliferation signature, and a down regulation of HEB/TCF12 target genes. Lastly, monoallelic deletion of Heb is sufficient to accelerate T-ALL onset in Cd3ε-deficient SCL-LMO1 transgenic mice. Together, these results underscore the role of HEB/TCF12 as a tumor suppressor in T-ALL.
Project description:Aberrant DNA methylation is a hallmark of cancer but mechanisms contributing to the abnormality remain elusive. Here, we report that most of lung cancer cell lines tested expressed predominantly ∆DNMT3B-del whereas normal bronchial epithelial cells expressed equal quantities of ∆DNMT3B and ∆DNMT3B-del. We demonstrate biological impacts of ∆DNMT3B4-del, a ∆DNMT3B-del isoform, in a transgenic mouse model. Expression of ∆DNMT3B4-del in the mouse lungs resulted in an increased global DNA hypomethylation, focal DNA hypermethylation, epithelial hyperplastia and tumor formation when challenged with a tobacco carcinogen. In patients with non-small cell lung cancer, 83% of the primary tumors expressed predominantly ∆DNMT3B-del. Our results demonstrate ∆DNMT3B4-del as a critical factor in developing aberrant DNA methylation during lung tumorigenesis.
Project description:Here we utilized a conditional knock-out mouse model to investigate the role of Smarca5, an ISWI subfamily chromatin remodeling ATPase, during thymocyte development using hCD2-iCre transgene. We did transcriptional profiling of FACS-sorted CD4/CD8 double-positive thymocytes as this thymic population was persistent yet strongly underrepresented in adult 6-week mutant thymi. Controls included age-matched CD4/CD8 double-positive thymocytes from wild-type and tumor suppressor protein Trp53-null mice. For comparison, the Smarca5/Trp53-double-deficient thymocytes included in the experiment were partially rescued upon loss of Trp53.
Project description:Dnmt3b is a tumor suppressor in oncogene-driven lymphoid and myeloid malignancies in mice. However, it is poorly understood whether reduced Dnmt3b activities can initiate malignant hematopoiesis. We modulated Dnmt3b activity in vivo by generating Dnmt3b+/− mice expressing one wild-type allele. Here, we analyzed methylation and gene expression in Dnmt3b+/- peripheral T-cell lymphomas (PTCLs).
Project description:comparative genome hybridisation of Hdac1/2 cKO lymphomas and matched normal tissue Histone deacetylases (HDACs) are epigenetic erasers of lysine-acetyl marks. Inhibition of HDACs using small molecule inhibitors (HDACi) is a potential strategy in the treatment of various diseases and is approved for treating hematological malignancies. Harnessing the therapeutic potential of HDACi requires knowledge of HDAC-function in vivo. Here, we generated a thymocyte-specific gradient of HDAC-activity using compound conditional knockout mice for Hdac1 and Hdac2. Unexpectedly, gradual loss of HDAC-activity engendered a dosage dependent accumulation of immature thymocytes and correlated with the incidence and latency of monoclonal lymphoblastic thymic lymphomas. Strikingly, complete ablation of Hdac1 and Hdac2 abrogated lymphomagenesis due to a block in early thymic development. Genomic, biochemical and functional analyses of pre-leukemic thymocytes and tumors revealed a critical role for Hdac1/Hdac2-governed HDAC-activity in regulating a p53-dependent barrier to constrain Myc-overexpressing thymocytes from progressing into lymphomas by regulating Myc-collaborating genes. One Myc-collaborating and p53-suppressing gene, Jdp2, was derepressed in an Hdac1/2-dependent manner and critical for the survival of Jdp2-overexpressing lymphoma cells. Although reduced HDAC-activity facilitates oncogenic transformation in normal cells, resulting tumor cells remain highly dependent on HDAC-activity, indicating that a critical level of Hdac1 and Hdac2 governed HDAC-activity is required for tumor maintenance. genomic DNA from LckCre+;Hdac1/2 cKO lymphomas and matched normal genomic DNA was hybridized onto a Nimblegen whole genome array
Project description:Purpose: The goal of this study was to identify the gene expression profile of mouse retina which carries deletions in Dnmt1, Dnmt3a and Dnmt3b genes. Method: Retinal mRNA profiles of Postnatal day 15 wild type mice and Dnmt1, Dnmt3a and Dnmt3b mutant mice were generated by deep-sequencing
Project description:<p>Germline or somatic loss-of-function of fumarate hydratase (FH) predisposes patients to an aggressive form of renal cell carcinoma (RCC). Since other than tumor resection, there is no effective therapy for FH-deficient RCC, a competent method for early diagnosis and for early detection of recurrent and metastatic disease is an unmet clinical need. Currently, at best, an annual MRI scan is offered, though typically, MRI is used for symptomatic patients only. Therefore, finding specific and sensitive biomarkers suitable for routine and simple screens is crucial for improving the clinical outcome of these patients. Taking advantage of the robust metabolic rewiring that occurs in FH-deficient cells, we performed a large-scale study of plasma metabolomics comparing FH-deficient RCC patients to no-tumor control individuals or to wildtype FH RCC patients. Our results indicated two fumarate-derived metabolites, succinyl-adenosine and succinic-cysteine, to be outstanding plasma biomarkers for early diagnosis, with a positive predictive value of more than 90%. Furthermore, using pre-clinical and biochemical studies, we identified the enzymatic mechanisms by which these biomarkers are produced in and around the tumors. </p>
