Project description:Expression of P190 and P210 BCR/ABL1 in normal human CD34(+) cells induces similar gene expression profiles and results in a STAT5-dependent expansion of the erythroid lineage The P190 and P210 BCR/ABL1 fusion genes are mainly associated with different types of hematologic malignancies, but it is presently unclear whether they are functionally different following expression in primitive human hematopoietic cells. We investigated and systematically compared the effects of retroviral P190 BCR/ABL1 and P210 BCR/ABL1 expression on cell proliferation, differentiation, and global gene expression in human CD34(+) cells from cord blood. Expression of either P190 BCR/ABL1 or P210 BCR/ABL1 resulted in expansion of erythroid cells and stimulated erythropoietin-independent burst-forming unit-erythroid colony formation. By using a lentiviral anti-signal transducer and activator of transcription 5 (STAT5) short-hairpin RNA, we found that both P190 BCR/ABL1- and P210 BCR/ABL1-induced erythroid cell expansion were STAT5-dependent. Under in vitro conditions favoring B-cell differentiation, neither P190 nor P210 BCR/ABL1-expressing cells formed detectable levels of CD19-positive cells. Gene expression profiling revealed that P190 BCR/ABL1 and P210 BCR/ABL1 induced almost identical gene expression profiles, and we identified a common set of 222 differentially expressed genes. Our data suggest that the early cellular and transcriptional effects of P190 BCR/ABL1 and P210 BCR/ABL1 expression are very similar when they are expressed in the same human progenitor cell population, and that STAT5 is an important regulator of BCR/ABL1-induced erythroid cell expansion. Keywords: global gene expression profiling, BCR/ABL1, CD34+ cord blood cells, CML, Ph+ ALL
Project description:The 8p11 myeloproliferative syndrome (EMS), also referred to as the stem cell leukemia/lymphoma syndrome, is a chronic myeloproliferative disorder that rapidly progresses into an acute leukemia. Molecularly, EMS is characterized by fusion of various partner genes to the FGFR1 gene, resulting in constitutive activation of the tyrosine kinase activity within FGFR1. The two most common fusion genes in human EMS are ZMYM2/FGFR1 (previously known as ZNF198/FGFR1) and BCR/FGFR1. To study the transcriptional programs becoming deregulated by the FGFR1 fusion genes, global gene expression analysis on human CD34+ cord blood cells expressing either of the fusion oncogenes ZMYM2/FGFR1 and BCR/FGFR1 was performed. As a reference gene we also included the more studied BCR/ABL1 fusion oncogene associated with chronic myeloid leukemia. We found that the 3 different fusion oncogenes had in common the upregulation of several genes involved in the JAK/STAT signalling pathway and also other sets of genes. However, the gene expression profiles were not identical, suggesting that both the tyrosine kinase containing gene and the partner gene would affect the transcription of downstream target genes. Bicistronic retroviral murine stem cell virus (MSCV) vectors expressing ZMYM2/FGFR1, BCR/FGFR1or P210 BCR/ABL1 and GFP were used. The MIG control vector expressed GFP only. Two days post transfection of human CD34+ umbilical cord blood cells, GFP-sorted cells were collected in three biological replicates and RNA was isolated immediately. In total, 12 samples were hybridized and scanned.
Project description:Philadelphia (Ph) chromosome-positive leukemia is characterized by the BCR/ABL1 fusion protein that affects a wide range of signal transduction pathways. The knowledge about its downstream target genes is, however, still quite limited. To identify novel BCR/ABL1-regulated genes we used global gene expression profiling of several Ph-positive and Ph-negative cell lines treated with imatinib. Following imatinib treatment, the Ph-positive cells showed decreased growth, viability, and reduced phosphorylation of BCR/ABL1 and STAT5. In total, 142 genes were identified as being dependent on BCR/ABL1-mediated signaling, mainly including genes involved in signal transduction, e.g. the JAK/STAT, MAPK, TGFB and insulin signaling pathways, and in regulation of metabolism. Interestingly, BCR/ABL1 was found to activate several genes involved in negative feedback regulation (CISH, SOCS2, SOCS3, PIM1, DUSP6, and TNFAIP3), which may act to indirectly suppress the tumor promoting effects exerted by BCR/ABL1. In addition, several genes identified as deregulated upon BCR/ABL1 expression could be assigned to the TGFB and NFkB signaling pathways, as well as to reflect the metabolic adjustments needed for rapidly growing cells. Apart from providing important pathogenetic insights into BCR/ABL1-mediated leukemogenesis, the present study also provides a number of pathways/individual genes that may provide attractive targets for future development of targeted therapies. Keywords: global gene expression profiling, Ph chromosome, BCR/ABL1, imatinib mesylate
Project description:Purpose: We identified a rare instance of the SFPQ-ABL1 in a child with Ph-like ALL. The overall purpose of this study was to compare the structure and function of the SFPQ-ABL1 fusion to the well characterised BCR-ABL1 fusion. We used phosphoproteomics, transcriptomics and functional assays to determine the transforming capacity, subcellular localisation, and signalling networks of these two fusions. Given the known function of SFPQ in mRNA splicing, transcriptomic analysis was performed to analyse the effect of BCR-ABL1 or SFPQ-ABL1 expression on gene splicing. Methods: mRNA profiles of Ba/F3 cells expressing BCR-ABL1, SFPQ-ABL1, and empty vector control (MSCV) were generated by deep sequencing, in four biologically independent cell lines, using Illumina GAIIx. The sequences were aligned by subread and quantified by featureCounts. Results: In contrast to BCR-ABL1, SFPQ-ABL1 localised to the nuclear compartment and was a weaker driver of cellular proliferation. Phosphoproteomics analysis showed upregulation of cell cycle, DNA replication and spliceosome pathways, and downregulation of signal transduction pathways, including ErbB, NF-kappa B, VEGF, and MAPK signalling in SFPQ-ABL1-, compared to BCR-ABL1-expressing cells. SFPQ-ABL1 expression did not activate PI3K/AKT signalling and was associated with phosphorylation of G2/M cell cycle proteins. We identified no difference in overall splicing between cells expressing BCR-ABL1 and SFPQ-ABL1. Conclusions: SFPQ-ABL1 has functionally distinct mechanisms by which it drives ALL, including subcellular localisation, proliferative capacity, and activation of cellular pathways, highlighting the role that fusion partners have in mediating the function of ABL1 fusions.
Project description:Philadelphia-like (Ph-like) acute lymphoblastic leukaemia (ALL) is a high-risk subtype of B-cell ALL characterised by a gene expression profile resembling Philadelphia Chromosome positive ALL (Ph+ ALL) in the absence of BCR-ABL1. Tyrosine kinase activating fusions, some involving ABL1, are recurrent drivers of Ph-like ALL and are targetable with tyrosine kinase inhibitors (TKIs). We identified a rare instance of SFPQ-ABL1 in a child with Ph-like ALL. SFPQ-ABL1 expressed in cytokine-dependent cell lines was sufficient to transform cells which were sensitive to ABL1-targeting TKIs. In contrast to BCR-ABL1, SFPQ-ABL1 localised to the nuclear compartment and was a weaker driver of cellular proliferation. Phosphoproteomics analysis showed upregulation of cell cycle, DNA replication and spliceosome pathways, and downregulation of signal transduction pathways, including ErbB, NF-kappa B, VEGF, and MAPK signalling in SFPQ-ABL1-, compared to BCR-ABL1-expressing cells. SFPQ-ABL1 expression did not activate PI3K/AKT signalling and was associated with phosphorylation of G2/M cell cycle proteins. SFPQ-ABL1 was sensitive to navitoclax and S-63845 and promotes cell survival through upregulation of Mcl-1 and Bcl-xL. SFPQ-ABL1 has functionally distinct mechanisms by which it drives ALL, including subcellular localisation, proliferative capacity, and activation of cellular pathways, highlighting the role that fusion partners have in mediating the function of ABL1 fusions.
Project description:To gain a global view on the impact of the collateral activity on protein expression levels, mass spectrometry was used for proteomics analysis of HEK 293T cells when PspCas13b was co-expressed with non-targeted (NT) crRNA or targeting (T) crRNA, which targets the BCR-ABL1 mRNA breakpoint. There was no evidence of off-target protein degradation by T crRNA compared to the non-targeting crRNA. The only significantly repressed proteins were the target BCR-ABL1 p190 (81% reduction) and eGFP (89% reduction) that are encoded on the same mRNA expression construct and encoded mRNA. Catalytic dead Cas13 (dCas13) and crRNA only were used as negative control.
Project description:Human B cell lineage acute lymphoblastic leukemia (ALL) cells carrying MLL-AF4 (SEM; BEL) and E2A-PBX1 (697) gene rearrangements were transduced with the mouse ecotropic receptor to permit subsequent entry of retroviral BCR-ABL1 GFP and GFP empty vectors (EV) pseudotyped with murine ecotropic envelope. GFP expression was measured by flow cytometry. Transductions with BCR-ABL1 GFP and GFP empty vectors (EV) were performed in the presence and absence of 2 mmol/l Imatinib (TKI). Washout of Imatinib in one series of experiments is indicated with an arrow. To study gene expression changes in MLL-AF4 and E2A-PBX1 B cell lineage ALL cells that were transduced with empty vectors (EV), BCR-ABL1 GFP in the presence of Imatinib (BCR-ABL1 OFF), washout of Imatinib (BCR-ABL1 ON) and subsequent re-addition of Imatinib, microarray analyses were performed.
Project description:In order to investigate the function of MYC in ALL, we isolated bone marrow cells from conditional MYC knockout mice and transformed them with BCR-ABL1. In a second transduction the BCR-ABL1 driven pre-B cells were transformed either with CRE or empty vector control.
Project description:In order to investigate the function of MYC in ALL, we isolated bone marrow cells from conditional MYC knockout mice and transformed them with BCR-ABL1. In a second transduction the BCR-ABL1 driven pre-B cells were transformed either with CRE or empty vector control. Three days post transduction, total RNA of GFP positive sorted cells were extracted and subjected to gene expression analysis.
Project description:In order to investigate the function of PAX5 in ALL, we isolated bone marrow cells from C57Bl6 mice and transformed them with BCR-ABL1. In a second transduction the BCR-ABL1 driven pre-B cells were transformed either with PAX5-GFP or empty vector control (GFP) and subjected to gene expression analysis. Three days post transduction, total RNA of GFP positive sorted cells were extracted and subjected to gene expression analysis.