Project description:T-cell prolymphocytic leukemia (T-PLL) is a rare post-thymic T-cell neoplasm with aggressive clinical course and short overall survival. So far, due to the rareness of this disease, genetic data is available only from individual cases or small cohorts. In our study, we aimed at performing a comprehensive cytogenetic and molecular genetic characterization of T-PLL comprising the largest cohort of patients with T-PLL analyzed so far, including correlations between the respective markers and their impact on prognosis. Genetic abnormalities were found in all 51 cases with T-PLL, most frequently involving the TCRA/D locus (86%). Deletions were detected for ATM (69%) and TP53 (31%), whereas i(8)(q10) was observed in 61% of cases. Mutations in ATM, TP53, JAK1 and JAK3 were detected in 73%, 14%, 6%, and 21% of patients, respectively. Additionally, BCOR mutations were observed for the first time in a lymphoid malignancy (8%). Two distinct genetic subgroups of T-PLL were identified: A large subset (86% of patients) showed abnormalities involving the TCRA/D locus activating the proto-oncogenes TCL1 or MTCP1, while the second group was characterized by a high frequency of TP53 mutations (4/7 cases). Further, analyses of overall survival identified JAK3 mutations as important prognostic marker, showing a significant negative impact.
Project description:Prior studies using DNA microarray platforms have shown alterations of gene expression profiles (GEPs) of marrow cells in myelodysplastic syndromes (MDS). Using the increased sensitivity and accuracy of high-throughput RNA sequencing (RNA-Seq) for detecting and quantifying mRNA transcripts, our study has demonstrated novel significant differences in GEPs between MDS and normal CD34+ marrow cells with 41 genes identified as disease classifiers. Additionally, two main clusters of GEPs distinguished patients based on their major clinical features, particularly between those whose disease remained stable (sMDS) vs patients whose illness transformed to acute myeloid leukemia within 12 months (tMDS). The genes whose expression was associated with disease outcome were involved in functional pathways and biologic processes highly relevant for MDS. Exomic analysis identified MDS-associated pathogenic mutations in virtually all patients tested. MDS subgroups with spliceosome mutations demonstrated distinct differential isoform usage and expression and consequent dysregulation of distinct biological functions. This combination of clinical, transcriptomic and exomic findings provides valuable molecular insights into the mechanisms underlying MDS and its progression to a more aggressive stage and also facilitates prognostic characterization of MDS patients.
Project description:T cell prolymphocytic leukemia (T-PLL) is mostly characterized by aberrant expansion of small to medium sized pro-lymphocytes with a mature post-thymic phenotype, high aggressiveness of the disease and poor prognosis. However, T-PLL is more heterogeneous with a wide-range of clinical, morphological, and molecular features, which occasionally impedes the diagnosis. We hypothesized that T-PLL consists of phenotypic and genotypic subgroups that may explain the heterogeneity of the disease. We found that T-PLL does not show a clear skewing in T cell receptor alpha (TRA), TRB gene usage and CDR3 stereotypy. In addition, multi-dimensional immuno-phenotyping and gene expression profiling did not reveal clear T-PLL subgroups. However, based on miRNA expression profiles, T-PLL samples did clearly cluster in subgroups. We identified 35 miRNAs that were aberrantly expressed in T-PLL with miR-200c/141 as the most differentially expressed cluster. High miR-200c/141 expression was significantly correlated with increased white blood cell counts and poor survival. Furthermore, we found that overexpression of miR-200c/141 in T-PLL correlated with downregulation of their targets ZEB2 and TGFβR3, indicating that the TGFβ pathway is affected. Our results thus highlight the emerging role for aberrantly expressed oncogenic miRNAs in T-PLL, thereby paving the way for new therapeutic targets in this disease.
Project description:T cell prolymphocytic leukemia (T-PLL) is mostly characterized by aberrant expansion of small to medium sized pro-lymphocytes with a mature post-thymic phenotype, high aggressiveness of the disease and poor prognosis. However, T-PLL is more heterogeneous with a wide-range of clinical, morphological, and molecular features, which occasionally impedes the diagnosis. We hypothesized that T-PLL consists of phenotypic and genotypic subgroups that may explain the heterogeneity of the disease. We found that T-PLL does not show a clear skewing in T cell receptor alpha (TRA), TRB gene usage and CDR3 stereotypy. In addition, multi-dimensional immuno-phenotyping and gene expression profiling did not reveal clear T-PLL subgroups. However, based on miRNA expression profiles, T-PLL samples did clearly cluster in subgroups. We identified 35 miRNAs that were aberrantly expressed in T-PLL with miR-200c/141 as the most differentially expressed cluster. High miR-200c/141 expression was significantly correlated with increased white blood cell counts and poor survival. Furthermore, we found that overexpression of miR-200c/141 in T-PLL correlated with downregulation of their targets ZEB2 and TGFβR3, indicating that the TGFβ pathway is affected. Our results thus highlight the emerging role for aberrantly expressed oncogenic miRNAs in T-PLL, thereby paving the way for new therapeutic targets in this disease.
Project description:T cell prolymphocytic leukemia (T-PLL) is mostly characterized by aberrant expansion of small to medium sized pro-lymphocytes with a mature post-thymic phenotype, high aggressiveness of the disease and poor prognosis. However, T-PLL is more heterogeneous with a wide-range of clinical, morphological, and molecular features, which occasionally impedes the diagnosis. We hypothesized that T-PLL consists of phenotypic and genotypic subgroups that may explain the heterogeneity of the disease. We found that T-PLL does not show a clear skewing in T cell receptor alpha (TRA), TRB gene usage and CDR3 stereotypy. In addition, multi-dimensional immuno-phenotyping and gene expression profiling did not reveal clear T-PLL subgroups. However, based on miRNA expression profiles, T-PLL samples did clearly cluster in subgroups. We identified 35 miRNAs that were aberrantly expressed in T-PLL with miR-200c/141 as the most differentially expressed cluster. High miR-200c/141 expression was significantly correlated with increased white blood cell counts and poor survival. Furthermore, we found that overexpression of miR-200c/141 in T-PLL correlated with downregulation of their targets ZEB2 and TGFβR3, indicating that the TGFβ pathway is affected. Our results thus highlight the emerging role for aberrantly expressed oncogenic miRNAs in T-PLL, thereby paving the way for new therapeutic targets in this disease. We used gene expression profiling by microarray to determine gene expression differences between T-PLL samples and normal T-cell subets.
Project description:Midbrain dopamine (mDA) neurons constitute a heterogenous group of cells that have been intensely studied, not least because mDA neuron degeneration causes major symptoms in Parkinson’s disease. Diversity of mDA neurons has previously been well characterized anatomically but understanding diversity at a more complete molecular level has not previously been achieved. Here, we used single cell RNA sequencing of isolated mouse neurons expressing the transcription factor Pitx3, a marker for all types of mDA neurons. Analyses included cells isolated during development up until adulthood and was validated by histological characterization of newly identified markers. This characterization identified seven neuron subgroups divided in two major branches of developing Pitx3-expressing neurons. Five of these groups were dopaminergic, one glutamatergic and one GABAergic. Analyses also indicated evolutionary conservation of diversity in humans. This comprehensive molecular characterization will provide a molecular framework for further studies of the developing and mature mDA neuron subgroups in the mammalian brain.
Project description:Mutations in the interleukin-7 receptor (IL7R) or the JAK3 kinase occur frequently in T-cell acute lymphoblastic leukemia (T-ALL) and both are able to drive cellular transformation and the development of T-ALL in mouse models. However, the signal transduction pathways downstream of JAK3 mutations remain poorly characterized. Here, we describe the phosphoproteome downstream of the JAK3(L857Q)/(M511I) activating mutations in transformed Ba/F3 lymphocyte cells and human JAK3 mutated T-ALL samples. Novel peptides shown to be downstream of mutant JAK3 regulating RNA metabolism as well as epigenetic and apoptotic processes were validated using targeted PRM proteomics.
Project description:Medulloblastoma (MB) is the most common malignant brain tumor occurring in childhood and rarely found in adult. Based on transcriptome profile MB are currently classified into four major molecular groups reflecting a considerable biological heterogeneity: WNT-activated, SHH-activated, group 3 and group 4. Recently, DNA methylation profiling allowed the identification of additional subgroups within the four major molecular groups associated with different clinic-pathological and molecular features. Isocitrate Dehydrogenase-1 (IDH1) mutations have been described in several tumours, including gliomas, while in MB are exceptionally reported and not routinely investigated. By mean of magnetic resonance spectroscopy (MRS) we unequivocally assessed the presence the oncometabolite D-2-Hydroxyglutarate (2HG), a marker of IDH1 and IDH2 mutation, in a case of adult MB. Immunophenotypical work-up and methylation profiling assigned the diagnosis of MB, subclass SHH-A, and molecular testing revealed the presence of the non-canonical somatic IDH1(p.R132C) mutation and an additional GNAS mutation, also exceptionally described in MB. To our knowledge this is the first reported case of MB harboring both mutations together. Of note, tumour exhibited a heterogeneous phenotype with a tumour component displaying glial differentiation, with robust GFAP expression, and a component with conventional MB features and selective presence of GNAS mutation, suggesting coexistence of two different major tumour clones. These findings draw attention to the need of a deeper genetic characterization of MB in order to get insights into their biology and improve stratification and clinical management of the patients. Moreover, reported data underling the importance of performing MRS for the identification of IDH mutations in non-glial tumours. The use of throughput molecular profiling analysis and advanced medical imaging technology will certainly increase the frequency with which rare tumour entities will be identified. Whether they have any particular therapeutic implications or prognostic relevance requires further investigations.