Project description:In B-cell chronic lymphocytic leukemia (CLL), the non-hematopoietic stromal microenvironment plays a critical role in promoting tumor cell recruitment, activation, survival and expansion. Using the Eμ-TCL1 mouse model, we demonstrate that leukemic cells induce the activation of retinoid acid synthesis and signaling in stromal cells of the lymphoid microenvironment.
Project description:In B-cell chronic lymphocytic leukemia (CLL), the non-hematopoietic stromal microenvironment plays a critical role in promoting tumor cell recruitment, activation, survival and expansion. Using the Eμ-TCL1 mouse model, we demonstrate that leukemic cells induce the activation of retinoid acid synthesis and signaling in stromal cells of the lymphoid microenvironment.
Project description:B cell chronic lymphocytic leukemia (CLL) is often preceded by a benign monoclonal or oligoclonal CD5+ B cell lymphocytosis. We have generated transgenic mice expressing a catalytically inactive, dominant-negative recombination activating gene 1 (dnRAG1 mice) in the periphery. These animals develop an early-onset indolent CD5+ B cell lymphocytosis, caused in part by a defect in secondary V(D)J rearrangements initiated to alter autoreactive B cell receptor specificity. Hypothesizing that the CD5+ B cells accumulating in dnRAG1 mice represent a CLL precursor, we crossed dnRAG1 mice with CLL-prone Eµ-TCL1 mice to determine whether dnRAG1 expression in Eµ-TCL1 mice accelerates the onset of CLL-like disease. We find that CD5+ B cell expansion and CLL progression occurs more rapidly and uniformly in double-transgenic mice (DTG mice) compared to Eµ-TCL1 mice, but with similar phenotypic and leukemogenic features. To gain insight into genes or pathways responsible for CD5+ B cell accumulation in the transgenic mice, we performed comparative gene expression profiling studies using normal and CD5+ B cells isolated from wild-type and transgenic mice at either 12 weeks of age (pre-leukemia) or at CLL onset in DTG mice (using age-matched wild-type and single-transgenic mice as controls). These analyses confirm the upregulation of tolerogenic genes in CD5+ B cells and reveal a possible role for prolactin signaling in the regulation of receptor editing. This study suggests that a failure to remodel B cell antigen receptor genes in response to autoreactivity may promote the benign accumulation of CD5+ B cells, which may then be subjected to secondary genetic lesions that promote CLL progression. dnRAG1 mice were bred to Eµ-TCL1 mice to obtain cohorts of wild-type (WT), single-transgenic (dnRAG1 and Eµ-TCL1), and DTG mice. Splenic CD19+B220hiCD5- B cells from WT mice or CD19+CD5+ B cells from transgenic mice were purified using fluorescence activated cell sorting (FACS). Biotin end-labeled cDNA prepared from the sorted cells was hybridized to Mouse Gene 1.0 ST Arrays. These experiments were performed two independent times: once with a cohort of 12-week-old mice, and once with older mice (>34 weeks old) consisting of two ill DTG mice and their age-matched counterparts. At least two biological replicates were used where possible.
Project description:Approximately 800,000 leukaemia and lymphoma cases are diagnosed worldwide each year. Burkitt’s lymphoma and chronic lymphocytic leukaemia represent contrasting examples of B-cell cancers, modelled by Eμ-myc and Eμ-TCL1 mice, respectively. To better understand B-cell cancers and systemic effects of oncogenesis, tumours and plasma from these models were profiled by mass spectrometry proteomics. 8270 cellular and 2095 plasma proteins were fully quantitated by isobaric labelling, of which 695 and 279 demonstrated overabundance coinciding in both tumour models, respectively. Co-occurring upregulated cellular tumour processes included ribosome biogenesis, translation, cell cycle promotion and chromosome segregation. Tumour plasma overabundance highlighted immunity, inflammation, microenvironment interactions, a prolific tumour lysis signature and putative biomarkers of early-stage cancer. Integrative evaluation of tumours and plasma provided systemic insight not captured in isolation. Overall, these findings provide a detailed characterisation of systemic oncogenesis in two contrasting B-cell tumour models, identifying extensive common profiles in both tumour cells and plasma.
Project description:B cell chronic lymphocytic leukemia (CLL) is often preceded by a benign monoclonal or oligoclonal CD5+ B cell lymphocytosis. We have generated transgenic mice expressing a catalytically inactive, dominant-negative recombination activating gene 1 (dnRAG1 mice) in the periphery. These animals develop an early-onset indolent CD5+ B cell lymphocytosis, caused in part by a defect in secondary V(D)J rearrangements initiated to alter autoreactive B cell receptor specificity. Hypothesizing that the CD5+ B cells accumulating in dnRAG1 mice represent a CLL precursor, we crossed dnRAG1 mice with CLL-prone Eµ-TCL1 mice to determine whether dnRAG1 expression in Eµ-TCL1 mice accelerates the onset of CLL-like disease. We find that CD5+ B cell expansion and CLL progression occurs more rapidly and uniformly in double-transgenic mice (DTG mice) compared to Eµ-TCL1 mice, but with similar phenotypic and leukemogenic features. To gain insight into genes or pathways responsible for CD5+ B cell accumulation in the transgenic mice, we performed comparative gene expression profiling studies using normal and CD5+ B cells isolated from wild-type and transgenic mice at either 12 weeks of age (pre-leukemia) or at CLL onset in DTG mice (using age-matched wild-type and single-transgenic mice as controls). These analyses confirm the upregulation of tolerogenic genes in CD5+ B cells and reveal a possible role for prolactin signaling in the regulation of receptor editing. This study suggests that a failure to remodel B cell antigen receptor genes in response to autoreactivity may promote the benign accumulation of CD5+ B cells, which may then be subjected to secondary genetic lesions that promote CLL progression.
Project description:In human chronic lymphocytic leukemia (CLL) pathogenesis B cell antigen receptor signaling seems important for leukemia B cell ontogeny, whereas the microenvironment influences B cell activation, tumor cell lodging and provision of antigenic stimuli. Using the murine Eμ-Tcl1 CLL model, we demonstrate that CXCR5-controlled access to follicular dendritic cells (FDCs) confers proliferative stimuli to leukemia B cells. Intravital imaging revealed a marginal zone B cell-like leukemia cell trafficking route. Murine and human CLL cells reciprocally stimulated resident mesenchymal stromal cells through lymphotoxin-β-receptor activation, resulting in CXCL13 secretion and stromal compartment remodeling. Inhibition of lymphotoxin/lymphotoxin-β-receptor signaling or of CXCR5 signaling retards leukemia progression. Thus, CXCR5 activity links tumor cell homing, shaping a survival niche, and access to localized proliferation stimuli.
Project description:TCL1 is an an oncogene and transgenic (Tg) mice expressing TCL1 specifically in B-cells are well-characterized models for chronic lymphocytic leukemia. On the contrary, PTPROt is a phosphatase with tumor suppressor characteristics in many cancers including leukemia. Our hypothesis was that transgenic expression of PTPROt in the B-cells of TCL1 Tg mice will alleviate disease phenotype and allow the study of the in vivo mechanism of action of PTPROt. To test this we have generated Tg mice with B-cell specific expression of PTPROt and crossed these mice with the TCL1 Tg mice.
Project description:Tcl1 tg mice develop a chronic lymphocytic leukemia (CLL) -like disease. To investigate the contribution of the adhesion molecule CD44 to CLL pathophysiology, we developed a CD19Cre CD44flox/flox Tcl1 tg mouse with a B cell specific CD44 deficiency (CD44ΔB Tcl1 tg). We used the Clariom S mouse microarray from Affymetrix to investigate transcriptional differeneces between Tcl1 tg and CD44ΔB Tcl1 tg mice
Project description:'The REL gene, encoding the NF-κB subunit c-Rel, is frequently amplified in B-cell lymphoma and functions as a tumour promoting transcription factor. Here we report the surprising result that c-rel -/- mice display significantly earlier lymphomagenesis in the c-Myc driven, Eμ-Myc model of B-cell lymphoma. c-Rel loss also led to earlier onset of disease in a separate TCL1-Tg driven lymphoma model. Tumour reimplantation experiments indicated that this is an effect intrinsic to the Eμ-Myc lymphoma cells but, counter-intuitively, c-rel -/- Eμ-Myc lymphoma cells were more sensitive to apoptotic stimuli. To learn more about why loss of c-Rel led to earlier onset of disease, microarray gene expression analysis was performed on B-cells from 4-week old, wild type and c-rel -/- Eμ-Myc mice. Extensive changes in gene expression were not seen at this age but among those transcripts significantly downregulated by the loss of c-Rel was the B-cell tumour suppressor BTB and CNC homology 2 (Bach2). Q-PCR and western blot analysis confirmed loss of Bach2 in c-Rel mutant Eμ-Myc tumours at both 4 weeks and the terminal stages of disease. Moreover Bach2 expression was also downregulated in c-rel -/- TCL1-Tg mice and RelA Thr505Ala mutant Eμ-Myc mice. Analysis of wild type Eμ-Myc mice demonstrated that the population expressing low levels of Bach2 exhibited the earlier onset of lymphoma seen in c-rel-/- mice. Confirming the relevance of these findings to human disease, analysis of ChIP-Seq data revealed that Bach2 is a c-Rel and NF-κB target gene in transformed human B-cells, while treatment of Burkitt''s lymphoma cells with inhibitors of the NF-κB/IKK pathway or deletion of c-Rel or RelA resulted in loss of Bach2 expression. This data reveals a surprising tumour suppressor role for c-Rel in lymphoma development explained by regulation of Bach2 expression, underlining the context dependent complexity of NF-κB signalling in cancer.'
Project description:The function of ID4 in CLL development was studied in vivo using TCL1 transgenic mouse model that develop leukemia similar to human CLL. TCL1 mice with ID4 single knockout gene have accelerated CLL progression. Results from the animal study suggest ID4 as a tumor suppressor gene that might regulate cell proliferation and apoptosis in B lymphocytes. Gene expression in CD19-positive splenic B cells collected from 1-month old ID4+/-TCL1-tg and ID4+/+TCL1-tg mice was compared by microarray, the goal is to find ID4-regulated genes involved in CLL development.