Project description:The transcription factor E2A is essential for lymphocyte development. In this study, we describe a recurrent E2A gene deletion in at least 70% of patients with Sézary syndrome (SS), a subtype of T cell lymphoma. Loss of E2A results in enhanced proliferation and cell cycle progression via derepression of the proto-oncogene MYC and the cell cycle regulator CDK6. Furthermore, by examining the gene expression profile of SS cells following restoration of E2A expression, we identify a number of E2A-regulated genes that interfere with oncogenic signaling pathways including the Ras pathway. Several of these genes are down-regulated or lost in primary SS tumor cells. These data demonstrate a tumor suppressor function of E2A in human lymphoid cells and could help to develop new treatment strategies for human lymphomas with altered E2A activity.
Project description:The transcription factor E2A is essential for lymphocyte development. In this study, we describe a recurrent E2A gene deletion in at least 70% of patients with Sézary syndrome (SS), a subtype of T cell lymphoma. Loss of E2A results in enhanced proliferation and cell cycle progression via derepression of the proto-oncogene MYC and the cell cycle regulator CDK6. Furthermore, by examining the gene expression profile of SS cells following restoration of E2A expression, we identify a number of E2A-regulated genes that interfere with oncogenic signaling pathways including the Ras pathway. Several of these genes are down-regulated or lost in primary SS tumor cells. These data demonstrate a tumor suppressor function of E2A in human lymphoid cells and could help to develop new treatment strategies for human lymphomas with altered E2A activity.
Project description:The transcription factor E2A is essential for lymphocyte development. In this study, we describe a recurrent E2A gene deletion in at least 70% of patients with Sézary syndrome (SS), a subtype of T cell lymphoma. Loss of E2A results in enhanced proliferation and cell cycle progression via derepression of the proto-oncogene MYC and the cell cycle regulator CDK6. Furthermore, by examining the gene expression profile of SS cells following restoration of E2A expression, we identify a number of E2A-regulated genes that interfere with oncogenic signaling pathways including the Ras pathway. Several of these genes are down-regulated or lost in primary SS tumor cells. These data demonstrate a tumor suppressor function of E2A in human lymphoid cells and could help to develop new treatment strategies for human lymphomas with altered E2A activity. The E2A-deficient Sézary cell line Seax was transiently transfected with the E2A-expression constructs E47myc (a myc-tagged E47 construct) or E47-forced dimer (a construct coding for two covalently linked E47 molecules), respectively. Every experiment was performed as two replicates accompanied by control transfections with a Mock plasmid.
Project description:Runt-related transcription factor 3 (RUNX3) has been described as a tumor suppressor for gastric cancer and other solid malignancies. Despite its key role in physiological T-cell differentiation, there is rare information on its relevance for the development of human T-cell lymphoma or leukemia. Here we show that alterations of RUNX3 by either heterozygous deletion or methylation of its distal promoter can be observed in the tumor cells of 15/21 (71%) patients suffering from Sézary Syndrome (SS), an aggressive variant of cutaneous T-cell lymphoma. In consequence, mRNA levels of RUNX3/p46, the long isoform of RUNX3 – controlled by the proximal promoter – are significantly lower in SS tumor cells. Re-expression of RUNX3/p46 promotes apoptosis and slows down proliferation in a RUNX3/p46low cell line of cutaneous T-cell lymphoma. By this we present the first evidence that RUNX3 can act as a tumor suppressor in a human T-cell malignancy and suggest that this effect is predominantly mediated through the long isoform of this transcription factor, which has not been in the focus of previous studies.
Project description:Two major genetic pathways leading to colorectal carcinoma can well be distinguished; the ‘suppressor pathway’, which is characterized by inactivation of tumor-suppressor genes and the ‘mutator pathway’, which is characterized by microsatellite instability. The purpose of this study is to explore a third putative pathway; microsatellite and chromosome stable colorectal cancer where an alternative cancer-causative mechanism might play a role.
Project description:Anaplastic Large Cell Lymphoma (ALCL) is a mature T-cell lymphoma that can present as a systemic or primary cutaneous disease. Systemic ALCL represents 2-5% of adult lymphoma but up to 30% of all pediatric cases. Two subtypes of systemic ALCL are currently recognized on the basis of the presence of a translocation involving the Anaplastic Lymphoma Kinase ALK gene. Despite considerable progress, several questions remain open regarding the pathogenesis of both ALCL subtypes. To investigate the molecular pathogenesis and to assess the relationship between the ALK(+) and ALK(-)ALCL subtypes, we performed a genome-wide DNA profiling using high density, single nucleotide polymorphism (SNP) arrays (SNP-array) on a series of 63 cases and seven cell lines. The commonest lesions were losses at 17p13 and at 6q21, encompassing the TP53 and PRDM1 genes respectively. The latter gene, coding for BLIMP1, was inactivated by multiple mechanisms, more frequently, but not exclusively, in ALK(-)ALCL. In vitro and in vivo experiments showed that that PRDM1 is a tumor suppressor gene in ALCL models, likely acting as an anti-apoptotic agent. Losses of TP53 and/or PRDM1 were present in 52% of ALK(-)ALCL, and in 29% of all ALCL cases with a clinical implication. Genomic profiling of Anaplastic Large Cell Lymphoma
Project description:This SuperSeries is composed of the following subset Series: GSE33474: Tristetraprolin is a tumor suppressor that impairs Myc-induced lymphoma and abolishes the malignant state [bone marrow B cells]. GSE37790: Tristetraprolin is a tumor suppressor that impairs Myc-induced lymphoma and abolishes the malignant state [Lymphoma]. GSE37791: Tristetraprolin is a tumor suppressor that impairs Myc-induced lymphoma and abolishes the malignant state [retrovirally infected ex vivo lymphoma] Refer to individual Series
Project description:The cutaneous T-cell lymphoma Hut78 was treated with ribavirin for 120 h, and the gene expression of the treated cells was compared with respect to the expression of the cells without treatment. We evaluated the effect of treatment with ribavirin upon gene expression in a cutaneous T-cell lymphoma model, Hut78. Ribavirin treatment decreased approximately 90% of the viability of Hut78 cells. A complete genomic analysis of transcriptomic status after treatment with ribavirin of cutaneous T cell lymphoma Hut78 revealed an impact on the overall expression of transcripts.