Project description:Comparison of ATG gene family members in MPN pattients with normal controls One-Way ANOVA while contrasting ATG gene family members in 11 Normal (Control) with either 1) 13 PV samples 2) 24 ET samples or 3) 18 PMF samples
Project description:Patients with chronic Myeloproliferative Neoplasms (MPN) including polycythaemia vera (PV) and essential thrombocythemia (ET) exhibit unique clinical features, such as a tendency toward thrombosis and hemorrhage, and risk of disease progression to secondary bone marrow fibrosis and/or acute leukemia. Although an increase in blood cell lineage counts (quantitative features) contribute to these morbid sequelae, the significant qualitative abnormalities of myeloid cells that contribute to vascular risk are not well understood. Here, we address this critical knowledge gap via a comprehensive and untargeted profiling (using label free quantitative mass spectrometry) of the platelet proteome in a large (n= 140) cohort of patients (from two independent sites) with an established diagnosis of PV and ET. We discover distinct MPN platelet protein expression and confirm key molecular impairments associated with proteostasis and thrombosis mechanisms of potential relevance to MPN pathology.
Project description:Myeloproliferative neoplasms (MPN) are clonal hematopoietic diseases that include essential thrombocytosis (ET), polycythemia vera (PV) and primary myelofibrosis (PMF) as well as BCR-ABL+ chronic myelogenous leukemia (CML). In the past several years, studies with cDNA microarrays have defined patterns of gene expression corresponding to specific molecular abnormalities, oncologic phenotypes, and clinical outcomes in hematologic malignancies. This study was aimed at the description of a gene expression signature in MPN which would eventually present a new pathogenetic approaching and also diagnostic as well as prognostic information. Using cDNA microarray analysis, involving 25,100 unique genes, we studied the gene expression profile of the pluripotent hematopoietic CD34+ stem cells and mature granulocytes obtained from peripheral blood of ET, PV, PMF and CML patients compared with healthy individuals. The average number of CD34+ cells (cells/µl) in peripheral blood was approximately 6 in PV and ET, 111 in PMF and 2880 in CML as measured by flow cytometry. A somatic point mutation JAK2V617F was detected in 93% of PV, 73% of PMF and 55% of ET patients within genetically homogenous population. The homozigosity for JAK2V617F mutation was the highest in PV (60%), less prominent in PMF (42%) and low in ET (11%) patients. The JAK2V617F mutation negative patients were also negative for exon 12 mutations. Approximately 420, 680 and 1130 genes had unique expression among CD34+ cells of ET, PV and PMF patients, respectively. In addition comparing to healthy controls, ET, PV, PMF and CML patients showed difference in 840, 1180, 1160 and 2050 expressed genes, respectively. Furthermore, we studied EPO and JAK-STAT signaling pathways related genes expression in MPN. The FOS, RAF1 and JAK2 gene expression, related to EPO signaling pathway, was elevated in ET, PV, PMF and reduced in CML comparing to healthy controls. Related to these genes, the JAK2V617F mutation homozygous and heterozygous patients generally displayed more significant differences comparing to patients with no mutation. STAT5 gene expression was decreased in all MPN patients. CSF3R, STAT1 and STAT3 gene expression, related to JAK-STAT signaling pathway, was elevated in ET, PV, PMF and reduced in CML comparing to healthy controls. CREBBP gene expression was reduced in CD34+ cells of ET, PV and PMF patients, but during maturation it enhanced expression in granulocytes. In conclusion, molecular profiling of CD34+ cells and granulocytes revealed a certain number of genes with changed expression that, beyond their recognized function in disease pathogenesis, can be related to patients’ clinical characteristics and may have an imminent prognostic relevance.
Project description:Myeloproliferative neoplasms (MPN) are a heterogeneous group of clonal disorders characterized by aberrant hematopoietic proliferation and an intrinsic risk of progression to blast phase. The WHO classification 2022 identifies chronic myeloid leukemia and the BCR::ABL1 negative MPNs polycythemia vera, primary myelofibrosis and essential thrombocythemia as individual entities. However, overlaps, borderline findings or transitions between MPN subtypes occur and incomplete clinical data often complicates diagnosis. By conducting a thorough genetic analysis, we've developed a model that relies on 12 genetic markers to accurately stratify MPN patients. The model can be simplified into a decision tree for routine use. Comparing samples at chronic and blast phase revealed, that one third of patients lost their MPN driver-gene mutation, while mutations in splicing and chromatin modifying genes were stable, indicating a shared founder clone of chronic and blast phase with different driver mutations and therefore different progressing capacities. This was further supported by gain of typical de novo AML gene mutations, accompanied by gain of complex karyotypes and RAS pathway gene mutations. Our data suggest to perform a broader genetic screening at diagnosis and also at clinical progression, as driver mutations may change and the MPN driver mutations present at diagnosis may disappear.
Project description:Interferons (IFNs) are cytokines with potent anti-neoplastic properties and significant clinical activity in the treatment of myeloproliferative neoplasms (MPNs). The use of pegylated IFN for the treatment of MPNs has been of particular interest, with several clinical trials establishing clinical responses. Here we demonstrate that chromatin assembly factor 1 subunit B (CHAF1B) is overexpressed in MPN patients. Targeted silencing of CHAF1B enhances transcription of IFN-stimulated genes and promotes IFN-dependent anti-neoplastic effects against MPN patient-derived cells. Our findings suggest that targeting CHAF1B in combination with IFN therapy may offer an avenue for the development of effective combination therapies for the treatment of MPNs.
Project description:The myeloproliferative neoplasms (MPN) frequently progress to blast phase disease, an aggressive form of acute myeloid leukemia. To identify genes that suppress disease progression, we performed a focused CRISPR/Cas9 screen and discovered that depletion of LKB1/Stk11 led to enhanced in vitro self-renewal of murine MPN cells. Deletion of Stk11 in a mouse MPN model caused rapid lethality with enhanced fibrosis, osteosclerosis, and an accumulation of immature cells in the bone marrow, as well as enhanced engraftment of primary human MPN cells in vivo. LKB1 loss was associated with increased mitochondrial reactive oxygen species and stabilization of HIF1α, and downregulation of LKB1 and increased levels of HIF1α were observed in human blast phase MPN specimens. Of note, we observed strong concordance of pathways that were enriched in murine MPN cells with LKB1 loss with those enriched in blast phase MPN patient specimens, supporting the conclusion that STK11 is a tumor suppressor in the MPNs.
Project description:Pre B cell leukemia homeobox 1 (Pbx1) regulates the balance between self-renewal and differentiation of hematopoietic stem cells, and maintains proto-oncogenic transcriptional pathways implicated in several tumors. Its aberrant expression was found in a subset of myeloproliferative neoplasms (MPN) patients bearing the JAK2V617F mutation. To investigate if Pbx1 contributes to MPN, and to explore its potential as therapeutic target, we generated a new mouse strain, that we called JP, by crossing a known JAK2V617F inducible knock-in MPN model with a Pbx1 conditional-ko. In JP mice we can simultaneously activate the human JAK2 mutation and delete Pbx1. Typical MPN features, such as thrombocytemia and granulocytosis, did not develop in the absence of Pbx1. Erythrocytosis, initially displayed by JP mice, gradually resolved over time. Moreover, splenic myeloid metaplasia and in vitro cytokine independent growth were rescued by Pbx1 inactivation. Through RNA-Sequencing we analyzed molecular pathways downstream of Pbx1 and involved in MPN maintenance in stem and progenitor cells. The aberrant transcriptome in the MPN model compared to wild-type was rescued by the absence of Pbx1. Our results demonstrate that inhibition of the Pbx1-driven transcriptional program is beneficial in MPN. Modulation of Pbx1 activity by direct targeting or by targeting its downstream mediators might thus represent a novel therapeutic approach.
Project description:Myeloproliferative neoplasms (MPNs) arise via the acquisition of a driver mutation in a single hematopoietic stem cell (HSC), often decades prior to the development of a clinical phenotype. The most common MPN driver mutation, JAK2V617F, activates aberrant JAK/STAT signaling via cytokine receptors critical for myelopoiesis. Over time, this MPN HSC clone outcompetes its normal counterparts, leading to excessive myeloid cell production and contributes to lymphopenia in patients with MPNs and leades to elevated neutrophil-to-lymphocyte ratio (NLR), which is predictive of disease-related complications including thrombosis and mortality. We conducted this study to learn how hematopoiesis from the JAK2V617F clone affects lymphopoiesis in patients with MPNs. Although myeloid proliferation via aberrant JAK2 signaling is the most apparent mechanistic link between JAK2V617F and MPN phenotypes, our findings demonstrate that impaired lymphoid differentiation is an additional feature of JAK2V617F hematopoiesis, leading to the rarity of JAK2V617F lymphocytes despite the dominance of JAK2V617F HSCs in patients with MPNs. The combination of prolific myelopoiesis and defective lymphopoiesis from the JAK2V617F clone is a potential connection between MPN pathology and the surrogate markers, including NLR and lymphopenia, which hold prognostic significance. Based on our data, we speculate that, defective JAK2V617F lymphopoiesis and the consequent increased burden of lymphopoiesis from residual normal HSC clones drives the appearance of abnormal lymphocyte subsets, lymphoproliferative disease or T cell exhaustion in MPNs. Further study of MPN lymphopoiesis provides an opportunity to define the immune deficits underlying the myriad complications that affect patients with MPNs.
Project description:Low levels of MYB promote the development of myeloproliferative neoplasm (MPN). The cell type identified that can transplant the MPN phenotype has been identified as expressing KIT, CD11b and low levels of lineage markers (K11bL). We sought to identify changes in gene expression between wild type and MYB knockdown K11bL cells to identify potential targets of MYB that play a role in the establishment of MPN.
Project description:Transformation of post-myeloproliferative neoplasms into secondary (s) AML exhibit poor clinical outcome. In addition to increased JAK-STAT and PI3K-AKT signaling, post-MPN sAML blast progenitor cells (BPCs) demonstrate increased nuclear β-catenin levels and TCF7L2 (TCF4) transcriptional activity. Knockdown of β-catenin or treatment with BC2059 that disrupts binding of β-catenin to TBL1X (TBL1) depleted nuclear β-catenin levels. This induced apoptosis of not only JAKi-sensitive but also JAKi-persister/resistant post-MPN sAML BPCs, associated with attenuation of TCF4 transcriptional targets MYC, BCL-2 and Survivin. Co-targeting of β-catenin and JAK1/2 inhibitor ruxolitinib (rux) synergistically induced lethality in post-MPN sAML BPCs and improved survival of mice engrafted with human sAML BPCs. Notably, co-treatment with BET protein degrader ARV-771 and BC2059 also synergistically induced apoptosis and improved survival of mice engrafted with JAKi-sensitive or JAKi-persister/resistant post-MPN sAML cells. These preclinical findings highlight potentially promising anti-post-MPN sAML activity of combination of β-catenin and BETP antagonists against post-MPN sAML BPCs.