Project description:CTLA4-CD28 gene fusion has been reported to occur in diverse types of T-cell lymphoma. The fusion event is expected to convert inhibitory signals to activating signals promoting proliferation and potentially transformation of T-cells. To test the function of the CTLA4-CD28 fusion gene in vivo, we generated a murine model that expresses the gene in a T-cell specific manner. The transgenic mice show shorter life spans and inflammatory responses including lymphadenopathy and splenomegaly. T-cells show higher levels of activation and infiltrate various organs including skin and lung. T-cells, in particular CD4+ helper T-cells, were also readily transplanted to immunocompromised mice. Transcriptomic profiling revealed that the gene expression pattern in CD4+ cells most closely resembles that of adult T cell leukemia/lymphoma (ATLL). Consistently, we detected supernumerary Foxp3+ cells in transgenic and transplanted mice. This is the first report demonstrating the transforming activity of the CTLA4-CD28 fusion gene in vivo, and this murine model should be useful in dissecting the molecular events subsequent to the mutation in ATLL.
Project description:Matching molecularly targeted therapies with cancer subtype-specific gene mutations is revolutionizing oncology care. However, for rare cancers this approach is problematic due to the often poor understanding of the disease's natural history and phenotypic heterogeneity, making treatment of these cancers a particularly unmet medical need in clinical oncology. Advanced Sézary syndrome (SS), an aggressive, exceedingly rare variant of cutaneous T-cell lymphoma (CTCL) is a prototypical example of a rare cancer. Through whole genome and RNA sequencing (RNA-seq) of a SS patient's tumor we discovered a highly expressed gene fusion between CTLA4 (cytotoxic T lymphocyte antigen 4) and CD28 (cluster of differentiation 28), predicting a novel stimulatory molecule on the surface of tumor T cells. Treatment with the CTLA4 inhibitor ipilimumab resulted in a rapid clinical response. Our findings suggest a novel driver mechanism for SS, and cancer in general, and exemplify an emerging model of cancer treatment using exploratory genomic analysis to identify a personally targeted treatment option when conventional therapies are exhausted.
Project description:During activation, T cells integrate multiple signals from APCs and cytokine milieu. The blockade of these signals can have clinical benefits as exemplified by CTLA4-Ig, which blocks interaction of B7 co-stimulatory molecules on APCs with CD28 on T cells. Variants of CTLA4-Ig, abatacept and belatacept are FDA approved as immunosuppressive agents in arthritis and transplantation whereas murine studies suggested that CTLA4-Ig can be beneficial in a number of other diseases. However, detailed analysis of human CD4 cell hyporesponsivness induced by CTLA4-Ig has not been performed. Herein, we established a model to study effect of CTLA4-Ig on the activation of human naM-CM-/ve T cells in a human mixed lymphocytes system. Comparison of human CD4 cells activated in the presence or absence of CTLA4-Ig, showed that co-stimulation blockade during TCR activation does not affect NFAT signaling but results in decreased activation of NF-kB and AP-1 transcription factors followed by profound decrease in proliferation and cytokine production. The resulting T cells become hyporesponsive to secondary activation and, although capable of receiving TCR signals, fail to proliferate or produce cytokines, demonstrating properties of anergic cells. However, unlike some models of T cell anergy, these cells did not possess increased levels of TCR signaling inhibitor CBLB. Rather, the CTLA4-Ig induced hyporesponsiveness was associated with an elevated level of p27kip1 cyclin-dependent kinase inhibitor. Time series. Human resting and activated T cell dUTP mRNA-Seq profiles were generated on Illumina HiSeq2500
Project description:During activation, T cells integrate multiple signals from APCs and cytokine milieu. The blockade of these signals can have clinical benefits as exemplified by CTLA4-Ig, which blocks interaction of B7 co-stimulatory molecules on APCs with CD28 on T cells. Variants of CTLA4-Ig, abatacept and belatacept are FDA approved as immunosuppressive agents in arthritis and transplantation whereas murine studies suggested that CTLA4-Ig can be beneficial in a number of other diseases. However, detailed analysis of human CD4 cell hyporesponsivness induced by CTLA4-Ig has not been performed. Herein, we established a model to study effect of CTLA4-Ig on the activation of human naïve T cells in a human mixed lymphocytes system. Comparison of human CD4 cells activated in the presence or absence of CTLA4-Ig, showed that co-stimulation blockade during TCR activation does not affect NFAT signaling but results in decreased activation of NF-kB and AP-1 transcription factors followed by profound decrease in proliferation and cytokine production. The resulting T cells become hyporesponsive to secondary activation and, although capable of receiving TCR signals, fail to proliferate or produce cytokines, demonstrating properties of anergic cells. However, unlike some models of T cell anergy, these cells did not possess increased levels of TCR signaling inhibitor CBLB. Rather, the CTLA4-Ig induced hyporesponsiveness was associated with an elevated level of p27kip1 cyclin-dependent kinase inhibitor.
Project description:Ctla4-/- mice suffer from a severe autoimmunity characterized by indiscriminate self-reactive T cell activation. Itk-/-Ctla4-/- (DKO) mice are protected from lethal autoimmunity despite a fulminant autoimmune process in the LNs as self-reative T cells fail to migrate to destroy tissues. We used microarray to identify underlying differences in gene expression that could account for lack of migration of DKO T cells into tissues. CD4+CD25neg T cells from 3 weeks old male Ctla4-/- or DKO mice were sorted in duplicates, RNA was extracted using TRIzol reagent and microarray analysis performed with the Affymetrix MoGene 1.0 ST array
Project description:Cutaneous T-cell lymphomas (CTCL) are a group of rare hematological malignancies characterized by infiltration of malignant T-cells into the skin. Two main types of CTCL constitute of Mycosis Fungoides (MF), a more indolent form of the disease, and Sézary Syndrome (SS), the aggressive and leukemic variant with blood involvement. Sézary syndrome presents a significant clinical challenge due to its very aggressive nature, poor prognosis, and treatment resistance, and to date, the disease is known to be uncurable. Histone deacetylase inhibitors have gained attention in CTCL treatment with promising results, but they expose limited specificity and strong side effects. Recent genomic studies underscore the role of epigenetic modifiers in CTCL pathogenesis, prompting an investigation into HDAC10, a member of Class IIb HDACs, in SS. HDAC10 was investigated in different cancers, revealing its involvement in the cell cycle regulation, apoptosis, and autophagy, but its role in CTCL is unknown. In this study we aimed to determine the role of HDAC10 in Sezary Syndrome, focusing on its cellular localization, role in cell growth, and potential therapeutic target. We indicated that HDAC10 is overexpressed in SS patients and located mainly in the cytoplasm. Its overexpression leads to an inhibitory effect on apoptosis progression when exposed to the pro-apoptotic compound Camptothecin (CPT). Knockdown of HDAC10 resulted in reduced cell growth and induction of apoptosis and autophagy, highlighting its potential importance in CTCL pathogenesis. Whole transcriptome analysis indicated that HDAC10 is associated with crucial cancer-related pathways for example hematopoietic cell lineage, PI3K-Akt signaling pathway, pathways in cancer, Ras signaling pathway, MAPK signaling pathway or JAK-STAT signaling pathway, which are critical for the survival and proliferation of malignant T cells. Inhibition of HDAC10 with selective HDAC10i increased the sensitivity of Sézary cells to the pro-apoptotic compound camptothecin (CPT). Our findings demonstrate that HDAC10 plays a key role in the molecular background of Sézary syndrome, highlighting its importance in the cellular mechanisms of the disease
Project description:This study used tumour and paired normal samples from 28 Sézary Syndrome (SS) patients to define recurrent regions of chromosomal aberrations. Our data identified recurrent losses of 17p13.2-p11.2 and 10p12.1-q26.3 occurring in 71 and 68% of cases respectively; common gains were detected for 17p11.2-q25.3 (64%) and chromosome 8/8q (50%). Moreover, we identified novel genomic lesions recurring in more than 30% of tumours: loss of 9q13-q21.33 and gain of 10p15.3-10p12.2. In the Sézary Syndrome cases analysed, we could find several small and few large Uniparental Disomies involving interstitial or telomeric regions of LOH occurring mainly for chromosome 10 and to a lesser extent for chromosome 9 and 17. In the attempt to correlate Copy Number data and clinical parameters we find a relationship between complex pattern of chromosomal aberrations, involving at least three recurrent Copy Number alterations, and shorter survival. Integrating mapping and transcriptional data we were able to identify a total of 113 deregulated transcripts in aberrant chromosomal regions that included cancer related genes such as members of the NF-kB pathway (BAG4, BTRC, NKIRAS2, PSMD3, TRAF2) that might explain its constitutive activation in CTCL. Matching this list of genes with those discriminating patients with different survival times we identify several common candidates that might exert critical roles in Sézary Syndrome, like BUB3 and PIP5K1B.